FIELD OF THE INVENTION
The present invention relates to a flame retardant polymer composition
and a process of making thereof. More particularly, the invention relates to
a polyethylene terephthalate (PET) masterbatch with improved flame
retardant properties and a process of manufacturing thereof.
BACKGROUND OF THE INVENTION
Generally, the flammability of polymers can be decreased either by
altering the products of thermal decomposition in such a way that the
amount of nonflammable combustion products is increased at the expense
of flammable volatiles (solid-phase retardation), or by inhibiting oxidation
reactions in the gas phase through trapping of free-radical species (gasphase
retardation), or by a combination of these mechanisms.
The technology related to various aspects of polymer flammability, of
flame-retardant compounds for polymers, and of possible improvements in
the fire safety of our environment has undergone explosive growth in last
few decades .
Retardant is defined as a material that has been chemically treated to selfextinguish.
There are many textiles that can be "treated". For example,
treated cotton is sometimes used on garments since it will self-extinguish
and will typically not melt or drip. Polyester is a textile that is frequently
used and potentially causes the greatest harm. Polyester will also melt
and drip molten polymers which is also hazardous. It is the melting and
dripping that also causes safety concern.
Flame retardant material has been used to reduce the flammability in
polymeric materials. Flame retardants play a vital role in a system in:
generation of non-combustible gases, which dilutes the oxygen supply at
the surface of the burning polymer; endothermic reactions of degradation
2
products from the flame retardants with species present in the flame or
substrate; endothermic decomposition of the flame retardant; formation of
nonvolatile char or glassy film barrier, which minimizes diffusion of oxygen
to the polymer substrate and also reduces heat transfer from flame to
polymer
Flame-retardant compounds, in order to be useful, must fulfill complex
sets of requirements, many of which are specific for each product. A flame
retardants added to a polymer should, reduce flammability as compared to
unmodified polymer to a level specified for the products in terms of product
performance in a specific flammability test; reduce smoke generation
under specified condition of testing, reduce smoke generation, under
specified conditions of testing: not increase the toxicity of combustion
products from the modified polymer as compared to the unmodified
polymer; be retained in the product through normal use (including
exposure, cleaning, aging, etc.); and have acceptable or minimal effect
on other performance properties of the product in use.
Polyesters have considerable potential utility as molded components in the
automotive field, in appliance manufacture, and in the electrical industry.
Additionally, fibers and yarns of polyesters have been very popular in
carpeting and upholstery applications. In view of the nature of the
applications in which this polymer is usually employed, must have good
flame resistance and flame retardancy.
Considerable research efforts have been extended toward the goal of
improving the flame retardancy of the polyesters. To be acceptable in
commercial formulations, flame retardancy additives must be effective at
low concentrations, must be stable at polymer processing temperatures
and must not contribute excessively to polymer degradation at processing
temperatures. Furthermore, such flame retardant polyesters should be
3
developed in cost effective and environment friendly approach to reduce
their flammability and to improve their physical properties.
US 2005/0154099 relates to flame resistant polyester resin compositions
comprising 30 to 90 weight percent thermoplastic polyester; 1 to 30 weight
percent oligomeric aromatic phosphate ester; 1 to 25 weight percent
phenolic polymer; 1 to 35 weight percent of at least one melamine flame
retardant selected from melamine pyrophosphate, melamine phosphate,
melamine polyphosphate, melamine cyan urate, and mixtures thereof; and
optionally inorganic reinforcing agents.
Likewise, EP 1578856 discloses flame resistant, laser weldable polyester
resin compositions comprising melt-mixed blends of polyester, phosphorus
containing flame retardant, phenolic polymer, and acrylic polymer and
articles made therefrom.
In last few years, a significant progress has been made in the
development of halogen-free flame retardant polyester in textile and
packaging industry. The polymers or reactive monomers that are
inherently flame retarding usually contain phosphorous (P), silicon (Si),
Boron (B), Nitrogen (N) and other miscellaneous elements. Such flame
retardants can be used on their own or added to current bulk commercial
polymers to enhance flame retardancy of the base polymer.
EP 1425340 discloses a polyester composition that includes a poly
(butylene terephthalate), a nitrogen-containing flame retardant, and a
phosphorus-containing flame retardant, such that the weight ratio of the
total of the nitrogen-containing flame retardant and the phosphoruscontaining
flame retardant to poly (butylene terephthalate) is at least about
0.70, and the weight ratio of the phosphorus-containing flame retardant to
the nitrogen-containing flame retardant is at least about 1.0.
I
4
Many types of fire-retardants are used in poly(ethylene terephthalate),
PET, formulations, but the most common are additive phosphorus species
like ammonium polyphosphate which enhances charring, or halogenated
products used for their gas-phase action, inhibiting the ignition of the
volatile pyrolysis products. Halogenated species are amongst the most
effective fire-retardant species known, but they are gradually being
abandoned for environmental and safety reasons. Attention is therefore
turned to phosphorus compounds, mostly under the form of reactive fireretardants
copolymerised with the polymer.
EP 2588531 discloses a thermoplastic polyester composition comprising,
based on the total weight of the composition, a chlorine- and bromine-free
combination of: from 40 to 60 wt% of a polyester; from 25 to 35 wt% of a
reinforcing filler; from 2 to 8 wt% of a flame retardant synergist selected
from the group consisting; of melamine polyphosphate, melamine
cyanurate, melamine pyrophosphate, melamine phosphate, and
combinations thereof; from 5 to 15 wt% of a phosphinate salt flame
retardant; from more than 0 to less than 5 wt% of an impact modifier
component comprising a poly( ether-ester) elastomer and a (meth)acrylate
impact modifier; from more than 0 to 5 wt% poly(tetrafluoroethylene)
encapsulated by a styreneacrylonitrile copolymer; from more than 0 to 2
wt% of a stabilizer; wherein the thermoplastic polyester composition
contains less than 5 wt% of a polyetherimide.
However, a masterbatch of such halogen free flame-retardant polyester
has not been developed in the industry so far. The process of the present
invention incorporates one or more phosphorous based flame retardant
additives or combination of long chain molecules containing phosphorous
atom in polyethylene terephthalate during the melt phase polymerization
reaction. The flame retardant additive reacts with unreacted monomers or
I
5
other reactive end groups of monomers, oligomers, or pre-polymers during
esterification in the reactor. Thus the FR additive is uniformly distributed in
the polymer chain rendering permanent flame retardancy and enables
better processing of polymers by extrusion blow moulding process.
The polyester modified from such phosphorous based additives shows
the improved properties, e.g. high crystallinity, low moisture contents, low
oligomer contents, high glass transition temperature (T9) and high melting
point (T m). Such masterbatch gives flexibility of inventory management
whereby-it can be incorporated in any PET chips (super-bright, semi-dull,
full dull, etc.) and RPET; it can also be used in film & sheets. The contents
of phosphorous used in the PET can be varied as per the requirement.
The oxygen index, or limiting oxygen index (LOI), is the minimum
percentage of oxygen that is required to maintain flaming combustion of a
specimen under specified laboratory conqitions. Highly flammable
materials are likely to have a low LOI. The FR polyester disclosed in the
present disclosure has high LOI and because of that the polyesters have
very low tendency to burn. The LOI of the polyester is geneally at a level>
22. The content of the phosphorous in the finished polyester can be
adjusted to achieve the required LOI of the polyester. The masterbatch
can further be blended with the normal polyester to prepare homogeneous
flame-retardant polyester as per the requirement of the industry and
application in prevailing countries.
The flame-retardant polyester obtained in accordance to the process of
the present disclosure also meets the health, safety and recycling
standards in textile and packaging industry. Moreover, the polyester
composition contains reactive flame retardants which makes the polyester
thermally stable due to permanent bonding between the flame-retardant
6
comonomer and the polyester. Such modified flame-retardant PET grades
have permanent FR properties which are not lost on washing.
OBJECTIVE OF THE INVENTION
Some of the objects of the present invention which at least one
embodiment is adapted to provide, are described herein below:
It is an object of the present invention to provide a modified polyethylene
terephthalate (PET) polyester masterbatch in crystallized form which can
be blended with PET/RPET to get polyester with improved flame retardant
properties.
It is another object of the present invention to provide a process of
modified polyethylene· terephthalate (PET) polyester masterbatch
composition.
It is yet another object of the present invention to provide a halogen-free
and phosphorous based flame retardant polyethylene terphthalate
polyester masterbatch.
It is yet another object of the present invention to provide a flame retardant
PET masterbatch composition for textile and packaging applications.
It is yet another object of the present invention to provide a flame retardant
polyethylene polyester masterbatch with improved flame retardancy in
crystallized form so that it can be dried and processed like normal PET.
It is still another object of the present invention to provide a polyethylene
terephthalate (PET) polyester masterbatch for extrusion or molding
applications to obtain flame retardant finished products.
7
Other objects and advantages of the present invention will be more
apparent from the following description when read in conjunction with the
accompanying figures, if any, which are not intended to limit the scope of
the present invention.
SUMMARY OF THE INVENTION
In one aspect methods of making flame retardant polyester masterbatch
are provided. The methods provide a phosphorus based flame retardant
polyester that is capable of imparting permanent flame retardance in
normal polyethylene terephthalate and the masterbatch can also be melt
blended in required quantity with other polyesters and nylon to impart the
flame retardance to them. The methods includes polymerizing monomers,
oligomers or pre-polymers obtained from esterification of one or more
dicarboxylic acids and at least one diol with one or more additives and at
least one phosphorus based flame retardant additive to obtain the
amorphous polyester, and cry~talizing the amorphous polyethylene
terephthalate to form the FR masterbatch of the polyester.
In some embodiments, the methods for the preparation of a flame
retardant polyester include, preparing slurry of pure terephthalic acid
(PTA) and ethylene glycol (MEG) along with sodium acetate anhydrous
and pentaerythritol in presence of catalyst; preparing oligomers, prepolymers
along with low molecular weight oligomers by esterification of
slurry at inert atmosphere; polymerizing the oligomers, pre-polymers in
presence of phosphorus based flame retardant additive and one or more
catalysts or combinations thereof to extrude strands of molten polymer;
preparing amorphous chips from strands obtained; crystallizing the
amorphous chips obtained so obtained at temperature of about 120 oc to
150 oc for 2 to 6 hours to obtain crystalline polymer; solid state
polymerization at temperature of about 190 oc to 210 oc of said
crystallized polymer until the required intrinsic viscosity (IV) is achieved.
I
8
In yet another aspect, provided is a flame retardant polyester composition
for use in fiber and yarn manufacturing, said polyester product
characterized by low limiting oxygen index (LOI) having value greater than
22.
In some embodiments, a melt blend of the FR polyester with polyethylene
terephthalate exhibits a greater flame retardance of the target polymer
than a non-blended polyethylene terephthalate and the required LOI of the
target polymer can be achieved by adding requisite phosphorus content in
the target polymer. In other embodiments, a blend of the FR PET with
other polyesters and nylon exhibits improved flame retardant properties
compared to non-blended polyesters and nylon.
DETAILED DESCRIPTION OF THE INVENTION
Various embodiments are described hereinafter. 1} should be noted that
the specific embodiments are not intended as an exhaustive description or
as a limitation to the broader aspects discussed herein. One aspect
described in conjunction with a particular embodiment is not necessarily
limited to that embodiment and can be practiced with any other
embodiment(s).
As used herein, "about" will be understood by persons of ordinary skill in
the art and will vary to some extent depending upon the context in which it
is used. If there are uses of the term which are not clear to persons of
ordinary skill in the art, given the context in which it is used, "about" will
mean up to plus or minus 10% of the particular term.
The use of the terms "a" and "an" and "the" and similar referents in the
.. context of describing the elements (especially in the context of the
following claims) are to be construed to cover both the singular and the
. I
9
plural, unless otherwise indicated herein or clearly contradicted by context.
Recitation of ranges of values herein are merely intended to serve as a
shorthand method of referring individually to each separate value falling
within the range, unless otherwise indicated herein, and each separate
value is incorporated into the specification as if it were individually recited
herein. All methods described herein can be performed in any suitable
order unless otherwise indicated herein or otherwise clearly contradicted
by context. The use of any and all examples, or exemplary language
(e.g., "such as") provided herein, is intended merely to better illuminate the
embodiments and does not pose a limitation on the scope of the claims
unless otherwise stated. No language in the specification should be
construed as indicating any non-claimed element as essential.
In general, "substituted" refers to an alkyl, alkenyl, alkynyl, aryl, or ether
group, as defined below (e.g., an alkyl group) in which one or more bonds
to a hydrogen atom contained therein are replaced by a bond to: nonhydrogen
or non-carbon atoms. Substituted groups also include groups in
which one or more bonds to a carbon(s) or hydrogen(s) atom are replaced
by one or more bonds, including double or triple bonds, to a heteroatom.
Thus, a substituted group will be substituted with one or more
substituents, unless otherwise specified. In some embodiments, a
substituted group is substituted with 1, 2, 3, 4, 5, or 6 substituents.
Examples of substituent groups include: halogens (i.e., F, Cl, Br, and I);
hydroxyls; alkoxy, alkenoxy, alkynoxy, aryloxy, aralkyloxy, heterocyclyloxy,
and heterocyclylalkoxy groups; carbonyls (oxo); carboxyls; esters;
urethanes; oximes; hydroxylamines; alkoxyamines; aralkoxyamines; thiols;
sulfides; sulfoxides; sulfones; sulfonyls; sulfonamides; amines; N-oxides;
hydrazines; hydrazides; hydrazones; azides; amides; ureas; amidines;
guanidines; enamines; imides; isocyanates; isothiocyanates; cyanates;
thiocyanates; imines; nitro groups; nitriles (i.e., CN); and the like.
10
As used herein, Cm-Cn, such as C1-C12, C1-C8, or C1-C6 when used
before a group refers to that group containing m to n carbon atoms.
As used herein, "alkyl" groups include straight chain and branched alkyl
groups having from 1 to about 20 carbon atoms (i.e., C1-C20 alkyl), and
typically from 1 to 12 carbon atoms (i.e., C1-C12 alkyl) or, in some
embodiments, from 1 to 8 carbon atoms (i.e., C1-C8 alkyl). As employed
herein, "alkyl groups" include cycloalkyl groups as defined below. Alkyl
groups may be substituted or unsubstituted. This term includes, by way of
example, linear and branched hydrocarbyl groups such as methyl (CH3-),
ethyl (CH3CH2-), n-propyl (CH3CH2CH2-), isopropyl ({CH3)2CH-), n-butyl
(CH3CH2CH2CH2-), isobutyl ((CH3)2CHCH2-), sec-butyl
((CH3)(CH3CH2)CH-), !-butyl ({CH3)3C-), n-pentyl
(CH3CH2CH2CH2CH2-), and neopentyl ((CH3)3CCH2-).
Representative substituted alkyl groups may be substituted one or more
times with, for example, amino, thio, hydroxy, cyano, alkoxy, and/or halo
groups such as F, Cl, Br, and I groups. As used herein the term haloalkyl
is an alkyl group having one or more halo groups. In some embodiments,
haloalkyl refers to a per-haloalkyl group.
Cycloalkyl groups are cyclic alkyl groups such as, but not limited to,
cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, and cyclooctyl
groups. In some embodiments, the cycloalkyl group has 3 to 8 ring
members, whereas in other embodiments the number of ring carbon
atoms range from 3 to 5, 6, or 7. Cycloalkyl groups may be substituted or
unsubstituted. Cycloalkyl groups further include polycyclic cycloalkyl
groups such as, but not limited to, norbornyl, adamantyl, bornyl,
camphenyl, isocamphenyl, and carenyl groups, and fused rings such as,
but not limited to, decalinyl, and the like. Cycloalkyl groups also include
rings that are substituted with straight or branched chain alkyl groups as
II
defined above. Representative substituted cycloalkyl groups may be
mono-substituted or substituted more than once, such as, but not limited
to: 2,2-; 2,3-; 2,4-; 2,5-; or 2,6-disubstituted cyclohexyl groups or mono-,
di-, or tri-substituted norbornyl or cycloheptyl groups, which may be
substituted with, for example, alkyl, alkoxy, amino, thio, hydroxy, cyano,
and/or halo groups.
As used herein, "aryl", or "aromatic," groups are cyclic aromatic
hydrocarbons that do not contain heteroatoms. Aryl groups include
monocyclic, bicyclic and polycyclic ring systems. Thus, aryl groups
include, but are not limited to, phenyl, azulenyl, heptalenyl, biphenylenyl,
indacenyl, fluorenyl, phenanthrenyl, triphenylenyl, pyrenyl, naphthacenyl,
chrysenyl, biphenyl, anthracenyl, indenyl, indanyl, pentalenyl, and
naphthyl groups. In some embodiments, aryl groups contain 6-14 carbons,
and in others from 6 to 12 or even 6-10 carbon atoms in the ring portions
of the groups. The phrase "aryl groups" includes groups containing fused
rings, such as fused aromatic-aliphatic ring systems (e.g., indanyl,
tetrahydronaphthyl, and the like). Aryl groups may be substituted or
unsubstituted.
The term "includes" is used to mean "includes but not limited to", "include"
and "include but not limited to", "Including" and "including but not limited
to" are used interchangeably.
The polyester obtained in accordance with the method of the present
invention is herein also referred to as "Flame Retardant Polyester" or "FR
Polyester" or "FR PET" or "Modified Polyester'' and are used
interchangeably.
The terms "Flame Retardant Polyester'' and "Flame Retardant Polyester
Masterbatch" or "FR Polyester'' and "FR Polyester Masterbatch" or "FR
12
PET" and "FR PET Masterbatch" or "Modified Polyester'' and "Modified
Polyester Masterbatch", "Polyester'' and "Flame Retardant Polyester'' are
used interchangeably.
The term "flame retardant additive" refers to additives used to impart flame
retardant properties in polymers
The term "target polymer'' is a polymer in which FR polyester masterbatch
is blended to achieve the required LOI of the polymer.
Ratios, concentrations, amounts, and other numerical data may be
presented herein in a range format. It is to be understood that such range
format is used merely for convenience and brevity and should be
interpreted flexibly to include not only the numerical values explicitly
recited as the limits of the range, but also to include all the individual
numerical values or sub-ranges encompassed within that range as if each
numerical value and sub-range is explicitly recited. For example, 5 to 40
mole % should be interpreted to include not only the explicitly recited limits
of 5 to 40 mole %, but also to include sub-ranges, such as 10 mole% to
30 mole %, 7 mole % to 25 mole %, and so forth, as well as individual
amounts, including fractional amounts, within the specified ranges, such
as 15.5 mole %, 29.1 mole %, and 12.9 mole %, for example.
The term "intrinsic viscosity" (I.V.) as used herein is a measure of the
molecular mass of the polymer and is measured by dilute solution
viscosimetry (DSV) in a 3:2 mixture of phenol, 1,2 dichlorobenzene
solution, at 25 °C.
The term "Limiting Oxygen Index (LOI)" is the minimum concentration of
oxygen, expressed as a percentage that will support combustion of a
polymer.
13
In one aspect, methods are provided preparing flame retardant polyesters
and a masterbatch thereof for industrial applications such as textile,
apparel, carpet, plastics etc. which can impart improved permanent flame
retardancy. In one aspect methods of making flame retardant polyester
masterbatch are provided. The methods provide a halogen free flame
retardant polyester that is capable of imparting permanent flame
retardance in normal polyethylene terephthalate and the masterbatch
thereof can also be melt blended in required quantity with other polyesters
and nylon to impart the flame retardance to them. The methods includes
polymerizing monomers, oligomers or pre-polymers obtained from
esterification of one or more dicarboxylic acids and at least one diol with at
least one phosphorus based flame retardant additive to obtain the
amorphous polyester, and crystalizing the amorphous polyethylene
terephthalate to form the FR masterbatch of the polyester.
In some embodiments, the methods for the preparation of a flame
retardant polyester include, preparing slurry of pure terephthalic acid
(PTA) and ethylene glycol (MEG) along with sodium acetate anhydrous
and pentaerythritol in presence of catalyst; preparing oligomers, prepolymers
along with low molecular weight by esterification of slurry at inert
atmosphere; polymerizing the oligomers, pre-polymers in presence of at
one or more flame retardant additive, wherein at least one flame retardant
additive contains phosphorus atom and one or more catalysts or
combinations thereof to extrude strands of molten polymer; preparing
amorphous chips from strands obtained; crystallizing the amorphous chips
obtained so obtained at temperature of about 120 oc to 150 oc for 2 to 6
hours to obtain crystalline polymer; solid state polymerization at
temperature of about 190 oc to 210 oc of said crystallized polymer until
the required intrinsic viscosity (IV) is achieved.
14
In one aspect, a method of preparing a crystallized flame retardant
polyester is provided wherein the crystallized FR polyester exhibits an
intrinsic viscosity greater than about 0.75 dl/g, greater than about 0.5
dl/g, greater than about 0.3 dl/g, greater than about 0.25 dl/g, greater
than about 0.2 dllg, greater than about 0.15 dllg, or greater than about
0.10 dl/g. In some embodiments, the crystallized FR polyester exhibits an
intrinsic viscosity from about 0.1 dllg to about 10 dllg, about 0.2 dl/g to
about 1 dl/g, about 0.3 dllg to about 0.75 dl/g, about 0.4 dllg to about
0.5 dl/g, and ranges between and including any two of these values. In
some embodiments, the crystallized FR polyester exhibits an intrinsic
viscosity greater than 0.25 dl/g.
In one aspect, a method of preparing a crystallized flame retardant
polyester is provided wherein the crystallized FR polyester can be blended
with target polymer to achieve higher Limiting Oxygen Index (LOI) of the
target polymer. In some embodiments the LOI of the target polymers can
be achieved greater than 22, greater than 25, greater than 28, greater
than 31, greater than 35, greater than 38. In some embodiments, the
target polymer exhibits LOI from about 21 to 24, about 23 to 27, about 26
to 30, about 29 to 34, about 33 to 40, and ranges between and including
any two of these values. In some embodiments, the target polymer
exhibits an LOI greater than 25.
Examples of the target polymer is, but not limited to, polyesters and
polyamides. In some embodiments the, the target polyesters is, but not
limited to, PET, PBT, PTT, PEN, PCDT, or combination thereof. In some
embodiments the target polyamide is, but not limited to nylon 6, nylon 66,
-~"'C>r combination thereof.
15
The method further includes subjecting the crystallized FR polyester to
solid state polymerization (SSP). The SSP leads to an increase in the
molecular weight and/or intrinsic viscosity of the polyester product.
In another aspect, the amorphous polyester can be pre-crystallized using
known methods, e.g. using fluid bed crystallizer. The amorphous polyester
can be further crystallized to form a crystallized and further upgraded by
solid state polymerization. The crystallized FR polyester can then be used
as a masterbatch sample to produce polymer compositions such as
polyesters and polyamides.
In one aspect, the method includes preparation of the oligomer, prepolymer
in the esterification reaction and then polymerizing the oligomers
with at least one phosphorus based flame retardant additive. In one
embodiment, the pre-polymer or oligomer is produced by the esterification
pf a dicarboxylic acid, or an ester thereof, with an alkylene diol. Suitable
dicarboxylic acids or esters thereof are disclosed herein and include, but
are not limited to an aliphatic dicarboxylic acid, aliphatic dicarboxylate, a
cycloaliphatic dicarboxylic acid, cycloaliphatic dicarboxylate, an aromatic
dicarboxylic acid, aromatic dicarboxylate, or a combination thereof.
The FR polyester can be prepared from two or more dicarboxylic acid
residues. The dicarboxylic acid residue is selected .from the group as
consisting of aliphatic dicarboxylic acid, an aliphatic dicarboxylate, a
cycloaliphatic dicarboxylic acid, a cycloaliphatic dicarboxylate, an aromatic
dicarboxylic acid, or an aromatic dicarboxylate and combinations thereof.
Examples of aromatic dicarboxylic diacids include terephthalic acid,
isophthalic acid, 2, 6-napthalene dicarboxylic acid, and ester derivatives
thereof. Examples of aliphatic diacids include adipic acid, glutaric acid,
succinic acid, azelaic acid, and ester derivatives thereof.
16
In one embodiments, the dicarboxylic acid residue is selected from the
group consisting of terephthalic acid, dimethyl terephthalate, dimethyl
isophthalate, dimethyl-2,6-naphthalate, 2, 7 -naphthalenedicarboxylic acid,
dimethyl-2, 7 -naphthalate, 3,4'-diphenyl ether dicarboxylic acid, dimethyl-
3,4'diphenyl ether dicarboxylate, 4,4'-diphenyl ether dicarboxylic acid,
dimethyl-4,4'-diphenyl ether dicarboxylate, 3,4'-diphenyl sulfide
dicarboxylic acid, dimethyl-3,4'-diphenyl sulfide dicarboxylate, 4,4'diphenyl
sulfide dicarboxylic acid, dimethyl-4,4'-diphenyl sulfide
dicarboxylate, 3,4'-diphenyl sulfone dicarboxylic acid, dimethyl-3,4'diphenyl
sulfone dicarboxylate, 4,4'-diphenyl sulfone dicarboxylic acid,
dimethyl-4,4'-diphenyl sulfone dicarboxylate, 3,4'-
benzophenonedicarboxylic acid, dimethyl-3,4'-
benzophenonedicarboxylate, 4,4'-benzophenonedicarboxylic acid,
dimethyl-4,4'-benzophenonedicarboxylate, 1 ,4-naphthalene dicarboxylic
acid, dimethyl-1 ,4-naphthalate, 4,4'-methylene bis(benzoic acid), dimethyl-
4,4'-methylenebi~(benzoate), dimethyl oxalate, malonic acid, dimethyl
malonate, dimethyl succinate, methylsuccinic acid, 2-methylglutaric acid,
3-methylglutaric acid, dimethyl adipate, 3-methyladipic acid, dimethyl
azelate, sebacic acid, 1, 11-undecanedicarboxylic acid, 1,10-
decanedicarboxylic acid, undecanedioic acid, 1, 12-dodecanedicarboxylic
acid, hexadecanedioic acid, docosanedioic acid, tetracosanedioic acid,
dimer acid, dimethyl-1 ,4-cyclohexanedicarboxylate, dimethyl-1 ,3-
cyclohexanedicarboxylate, 1, 1-cyclohexanediacetic acid, metal salts of 5-
sulfo-dimethylisophalate, maleic anhydride, and combinations thereof.
Some non-limiting examples of dicarboxylic acid residue are isophthalic
acid, 2,6-napthalene dicarboxylic acid, oxalic acid, maleic acid, succinic
acid, glutaric acid, dimethyl glutarate, adipic acid, 2,2,5,5-
tetramethylhexahedioic acid, pimelic acid, suberic acid, azelaic acid, 1,4-
cyclohexanedicarboxylic acid, 1 ,3-cyclohexanedicarboxylic acid, 1,1-
17
cyclohexanediacetic acid, fumaric acid, maleic acid, hexahydrophthalic
acid, and phthalic acid.
The flame retardant polyester can be prepared using suitable methods
known in the art. For example, the dicarboxylic acid or ester thereof can
be reacted with an alkylene diol at a suitable temperature and pressure for
a sufficient amount of time to obtain the oligomers or pre-polymer having
end groups. Suitable esterification conditions can be employed for the
preparation of the FR polyester. For example, the reaction can be
conducted at a temperature of about 300 oc or below, about 200 oc or
below, about 100 oc or below, at about 80 oc or below, at about 50 oc or
below, at about 45 oc or below, at about 40 oc or below, at about 35 oc or
below, at about 30 oc or below, at about 25 oc or below or at about 20 oc
or below, and ranges between and including any two of these values. The
reaction can be conducted for a pressure of about 1 bar to about 30 bars,
about 2 bars to about 20 bars, abo~! 3 bars to about 10 bars, about 4 bars
to about 5 bars, and ranges between and including any two of these
values.
In some embodiments, the reaction pressure is up to about 20 bars, up to
about 10 bars, up to about 5 bars, up to about 3 bars, up to about 2 bars,
up to about 1 bar, and ranges between and including any two of these
values. The reaction can be conducted for a period of about 1 min to about
60 min, about 1 h to about 5 h, about 5 h to about 8 h, about 8 h to about
15 h, about 15 h to about 25 h, about 25 h to about 40 h, and ranges
between and including any two of these values. In some embodiments, the
reaction of dicarboxylic acid or ester thereof with an alkylene diol is
conducted at a temperature of about 240 •c to about 260 •c and at a
pressure of up to about 4 bars for about 2 h to about 3 h.
18
The phosphorus based flame retardant additive is selected from the group
consisting of 2-Carboxyethyl(phenyl) phosphinic acid or 3-
hydroxyphenylphosphinyl-propanoic acid), 9,1 0-dihydro-1 0-[2,3-
di(hydroxyl carbonyl) propyl] 1 0-phosphaphenanthrene-10-oxid, 2,2-
Bis(chloromethyl)trimethylene bis[bis (2-chloroethyl) Phosphate,
Chlorendic acid, tetrakis (2-chloroethyl) dichloroisopentyldiphosphate,
Tris(2-chloroethyl) phosphate, tris(1-chloro-2-propyl)phosphate, tris(2,3-
dichloro-1-propyl)phosphate, hexachlorocyclopentadienyldibromocyclooctane,
tetrakis(2-chloroethyl)dichloroisopentyldiphosphate,
tris(2-chloroethyl) phosphate, Poly(2,6-dibromo-phenylene oxide), tetradecabromo-
diphenoxy-benzene, 1 ,2-Bis(2,4,6-tribromo-phenoxy) ethane,
3,5,3,5-Tetrabromo-bisphenol A (TBBA),TBBA, unspecified, TBBAepichlorhydrin
oligomer, TBBA-TBBA-diglycidyl-ether oligomer, TBBA
carbonate oligomer, TBBA carbonate oligomer, phenoxy end capped,
TBBA carbonate oligomer, 2,4,6-tribromo-phenol terminated, TBBAbisphenol
A-phosgene polymer, brominated epoxy :resin end-capped with
tribromophenol, TBBA-(2,3-dibromo-propyl-ether), TBBA bis-(2-hydroxyethyl-
ether), TBBA-bis-(allyl-ether), TBBA-dimethyl-ether, Tetrabromobisphenol
S, TBBS-bis-(2,3-dibromo-propyl-ether), 2,4-dibromo-phenol,
2,4,6-tribromo-phenol, pentabromo-phenol, 2,4,6-Tribromo-phenyl-allylether,
tribromo-phenyl-allyl-ether, bis(methyl)tetrabromo-phtalate, Bis(2-
ethylhexyl)tetrabromo-phtalate, 2-Hydroxy-propyl-2-(2-hydroxy-ethoxy)ethyi-
TBP, TBPA, glycol-and propylene-oxide esters, N,N-Ethylene -bis-
(tetrabromo-phthalimide), ethylene-bis(5,6-dibromo-norbornane-2,3-
dicarboximide), 2,3-Dibromo-2-butene-1 ,4-diol, Dibromo-neopentyl-glycol,
Dibromo-propanol, tribromo-neopentyl-alcohol, poly tribromo-styrene and
combination thereof.
Examples of the phosphorus based flame retardant additive used in the
method include, but are not limited to, 2-carboxyethyl (phenyl) phosphinic
acid [also known as 3-(hydroxyphenylphosphinyl) propanoic acid], and/or
I
19
9,1 0-dihydro-1 0-[2,3-di(hydroxylcarbonyl)propyl]1 0-
phosphaphenanthrene-1 0-oxide, or combination thereof.
In some embodiments, the alkylene diols include C4-C5 branched
aliphatic diols. Examples of branched diols include, but are not limited to,
2-methyl-1, 3-propanediol, 2, 2-dimethyl-1, 3-propanediol, 2-butyl-2-ethyl-
1, 3-propanediol, trimethylpentanediol, and the like. The diol may be a
cycloaliphatic diol having between 6-20 carbon atoms, with the proviso
that if a cyclohexane diol is used, it is included with at least one-additional
cyclic or branched diol. For example, isosorbide or a mixture of (cis, trans)
1, 3-cyclohexanedimethanol and (cis, trans) 1, 4 cyclohexanedimethanol
may be used. Examples of aromatic diol may include xylene glycol, and
hydroquinone. In one embodiment the diol may be 1 ,3-propanediol, 1,4-
butanediol, 1 ,6-hexanediol, 1 ,8-octanediol, 1,1 0-decanediol, 1,12-
dodecanediol, 1, 14-tetradecanediol, 1, 16-hexadecanediol, dimer diol, 1,4-
cyclohexanedimethanol, di(ethylene ~lycol), tri(ethylene gl~col),
poly( ethylene ether) glycols, poly(butylene ether) glycols, 2-methyl-1 ,3-
propanediol, 2,2-dimethyl-1 ,3-propanediol, 2-butyl-2-ethyl-1 ,3-propanediol,
trimethylpentanediol, isosorbide or a mixture of (cis, trans) 1,3-
cyclohexanedimethanol and (cis, trans) 1,4 cyclohexanedimethanol,
xylene glycol, and hydroquinone.
The alkylene diol can be a straight chain or a branched diol having 2 to 12
carbon atoms per molecule. Examples of suitable diols include, but are not
limited to, ethylene glycol, propanediol, butanediol,
cyclohexanedimethanol, hexane diol, octanediol, decanediol,
dodecanediol, and combinations thereof. In some embodiments, the
preferred alkylene diol is ethylene glycol.
The FR polyester masterbatch may be produced by suitable
polymerization techniques known in the art. In some embodiments! the
20
flame retardant polyester is produced by any of the conventional melt or
solid state polycondensation techniques. The melt polycondensation
method can be carried out in either batch, semi-continuous or continuous
mode. In another embodiment, the melt polycondensation method can be
carried out in either batch reaction, or continous polymerization line. The
method is best carried out in a reactor equipped with a distillation column
and a stirrer or other means for agitation. The distillation column separates
the volatile product of reaction (water and/or alkanol) from volatile
reactants (e.g., ethylene glycol). Use of a distillation column allows for
operation at a lower molar ratio of ethylene glycol to terephthalic acid,
which serves to suppress the formation of DEG. Melt polycondensation
can be carried out in conventional method like PTA, DMT and PCR PET
glycolysis. When terephthalic acid is used in the polymerization method,
the volatile reaction product will be water; when an ester such as dimethyl
terephthalate is used, the volatile reaction product will be the
corresponding alkanol (such as methanol), together with smaller amounts
~£-~70-.c-~_ • .,_,:-- -
of water. Continuous polymerization method may be used to prepare
polyesters.
In one aspect, the method further includes crystallizing the amorphous
polyester to form a crystallized FR polyester. Suitable crystallization
techniques known in the art may be used to produce the crystallized FR
polyester. The crystallization reaction can be conducted by heating the
amorphous FR polyester at a suitable temperature for a suitable period of
time. For example, the crystallization can be conducted at a temperature
of about 10 octo about 300 oc, about 30 octo about 200 oc, about 50 oc
to about 250 oc about 80 oc to about 200 oc and about 100 oc to about
150 oc, and ranges between and including any two of these values. In
some embodiments, the amorphous FR polyester is crystallized at a
temperature in the range of about 110 oc to about 150 oc to produce a
crystallized FR polyester.
21
The reaction of producing of flame retardant polyester may further include
addition of one or more additives. In some embodiments, the additive is
selected from the group consisting of a nucleating agent, branching agent,
chain extender, antioxidant, plasticizers, stabilizing agent, a coloring agent
and other additives. Additives may also be added before or during or after
the polymerization reaction to impart requisite property to the resulting copolyester.
Such additives include but are not limited to dyes; pigments;
flame retardant additives such as decabromodiphenyl ether and
triarylphosphates, such as triphenylphosphate; reinforcing agents such as
glass fibers; thermal stabilizers; ultraviolet light stabilizers methoding aids,
impact modifiers, flow enhancing additives, ionomers, liquid crystal
polymers, fluoropolymers, olefins including cyclic olefins, polyamides and
ethylene vinyl acetate copolymers.
The additives described herein, for example, the plasticizer, anti-oxidizing
agent, stabilizing agent, and end-capped oligomer, if present, can be
incorporated for example, at a concentration in the range of about 0.001
wt%, about 0.01 wt%, about 0.02 wt%, about 0.05 wt%, about 0.1 wt%,
about 0.5 wt%, about 1.0 wt%, about 2 wt%, about 5 wt%, about 10.0
wt%, about 15.0 wt%, about 20.0 wt%, about 30.0 wt%, and ranges
betw.een any two of these values or less than any one of these values.
Other additives, such as for example, nucleating agent and the branching
agent, if present, can be incorporated for example, at a concentration in
the range of about 0.1 ppm to about 10,000 ppm, about 2 ppm to about
5000 ppm, about 5 ppm to about 7500 ppm, about 10 ppm to about 2000.
ppm, about 20 ppm to about 1000 ppm, or about 50 ppm to about 500
ppm, and ranges between any two of these values or less than any one of
these values.
22
In one aspect, the flame retardant polyester obtained by the methods
described herein is provided, wherein the polyester includes up to about
30 to about 90 wt% of the dicarboxylic acid, up to about 10 wt% to 70% of
the alkylene diol, up to about 0.01 wt% to about 10 wt% of one or more
flame retardant additives, and one or more reagents selected from the
group consisting of a liquid plasticizer, a nucleating agent, a branching
agent, an anti-oxidizing agent, and a stabilizing agent.
Examples of additives useful for the purpose of the present disclosure is at
least one selected from the group consisting of a liquid plasticizer, a
nucleating agent, a branching agent, an anti-oxidizing agent, a stabilizing
agent and an end-capped oligomer. In some embodiments, the additives
useful for the purpose of the present disclosure is at least one selected
from the group consisting of branching agent in an amount of 10 ppm to
2000 ppm, nucleating agent in an amount of 10 ppm to 2000 ppm and
liquid plasticizer in an amount, of 0.5 to 2 wt%, at least one stabilizing
agent and at least one anti-oxidizing agent in an amount ranging from 0.1
to 5 wt%. Other agents useful for the purpose of the present disclosure
include at least one end-capped oligomer in an amount from 1 to 20 wt%.
The branching agent useful for the purpose of the present disclosure
includes but is not limited to 1 ,2,4-benzenetricarboxylic acid (trimellitic
acid); trimethyl-1 ,2,4-benzenetricarboxylate; 1 ,2,4-benzenetricarboxylic
anhydride (trimellitic anhydride); 1 ,3,5-benzenetricarboxylic acid; 1 ,2,4, 5-
benzenetetracarboxylic acid (pyromellitic acid); 1 ,2,4,5-
benzenetetracarboxylic dianhydride (pyromellitic anhydride); 3,3',4,4'benzophenonetetracarboxylic
dian hydride; 1 ,4,5,8-
naphthalenetetracarboxylic dianhydride; citric acid; tetrahydrofuran-2,3,
4,5-tetracarboxylic
acid;pentaerythritol,
acid; 1 ,3,5-cyclohexanetricarboxylic
2-(hydroxymethyl)-1 ,3-propanediol; 2,2-
bis(hydroxymethyl) propionic acid; sorbitol; glycerol and combinations
23
thereof. Particularly, branching agents such aspentaerythritol, trimellitic
acid, trimellitic anhydride, pyromellitic acid,· pyromellitic anhydride and
sorbitol are used.
The nucleating agent improves the crystallinity and increases heat
deformation temperature of the polyester product. The nucleating agent
can be organic or inorganic. Examples of inorganic nucleating agent
include, but are not limited to, calcium silicate, nano silica powder, talc,
microtalc, aclyn, kaolinite, montmorillonite, synthetic mica, calcium sulfide,
boron nitride, barium sulfate, aluminum oxide, neodymium oxide and a
metal salt of phenyl phosphonate. The inorganic nucleating agent can be
modified by an organic material to improve its dispersibility in the polyester
product of the present disclosure.
Examples of organic nucleating agent include, but are not limited to,
carboxylic acid metal salts such as sodium benzoate, potassium benzoate,
lithium benzoate, calcium benzoate, magnesium benzoate, barium
benzoate, lithium · terephthalate, sodium terephthalate, potassium
terephthalate, calcium oxalate, sodium laurate, potassium laurate, sodium
myristate, potassium myristate, calcium myristate, sodium octacosanoate,
calcium octacosanoate, sodium stearate, potassium stearate, lithium
stearate, calcium stearate, magnesium stearate, barium stearate, sodium
montanate, calcium montanate, sodium toluoylate, sodium salicylate,
potassium salicylate, zinc salicylate, aluminum dibenzoate, potassium
dibenzoate, lithium dibenzoate, sodium j3-naphthalate and sodium
cyclohexane carboxylate; organic sulfonates such as sodium p-toluene
sulfonate and sodium sulfoisophthalate; carboxylic acid amides such as
stearic acid amide, ethylene bis-lauric acid amide, palmitic acid amide,
hydroxystearic acid amide, erucic acid amide and tris(t-butylamide)
trimesate; phosphoric compound metal salts such as benzylidene sorbitol
and derivatives thereof, sodium-2,2'-methylenebis(4,6-di-t-
24
butylphenyl)phosphate, and 2,2-methylbis(4,6-di-t-butylphenyl)sodium,
and the like, or combinations thereof.
Examples of liquid plasticizer useful for the purpose of the present
disclosure include, but are not limited to, N-isopropyl benzene
sulfonamide, N-tert-butyl benzene sulfonamide, N-pentyl benzene
sulfonamide, N-hexyl benzene sulfonamide, N-n-octyl benzene
sulfonamide, N-methyi-N-butyl benzene sulfonamide, N-methyi-N-ethyl
benzene sulfonamide, N-methyi-N-propyl benzene sulfonamide, N-ethyiN-
propyl benzene sulfonamide, N-ethyl p-ethylbenzenesulfonamide, Nethyl
p-(t-butyl)benzene sulfonamide, N-butyl p-butyl benzene
sulfonamide, N-butyl toluene sulfonamide, N-t-octyl toluene sulfonamide,
N-ethyi-N-2-ethylhexyl toluene sulfonamide, N-ethyi-N-t-octyl toluene
sulfonamide and tri-octyltrimellitate, and the like, or combinations thereof.
Examples of anti-oxidizing agent include, but are not limited to, irganox
1010, irganox 1076, irgafos 126 and irgafos 168. Similarly, copper nitrate
(up to 150 ppm) along with Potassium Iodide &/or Potssium bromides (up
to 1000 ppm ) or any other Light & UV Stabilizers which can be added to
enhance weatherability of the polymers.
Examples of stabilizing agent include, but are not limited to, orthophosphoric
acid, trimethylphosphate (TMP), triphynylphosphate (TPP) and
triethylphosphono · acetate (TEPA). In some embodiments, orthophosphoric
acid is used as stabilizing agent.
Examples of end-capped oligomer include, but are not limited to,
oligomers of polyethylene terephthalate, polybutylene terephthalate,
polytrimethylene terephthalate, polytreimethylenenaphthalate and
polybutylenenaphthalate, and the like, or combinations thereof.
25
The methods and products described herein may include other suitable
additives known in the art, which include but are not limited to, pigments
such as decabromodiphenyl ether and triarylphosphales, such as
triphenylphosphate, reinforcing agents such as glass fibers, thermal
stabilizers, ultraviolet light stabilizers methoding aids, impact modifiers,
flow enhancing additives, ionomers, liquid crystal polymers,
fluoropolymers, olefins including cyclic olefins, polyamides and ethylene
vinyl acetate copolymers.
In an embodiment of the invention, the catalysts may be selected from the
group consisting of antimony trioxide, antimony triacetate, Ti compounds,
germanium dioxide, tin compounds or combinations thereof.
In one embodiment, the method further includes subjecting the crystallized
FR polyester to solid state polymerization conditions. This will increase the
1 molecular weight and the intrinsic viscosity of the polyester. The solid stale
l polymerization is conducted under a vacuum or in the presence of a
stream of an inert gas. Suitable inert gases include, but are not limited to,
nitrogen, carbon dioxide, helium, argon, neon, krypton, xenon, and the
like. Suitable solid state polymerization temperatures can range from a
temperature at or above the polymerization reaction temperature up to a
temperature below their melting point. For example, the solid state
polymerization reaction can be conducted at a temperature of about 400
·cor below, about 300 ·cor below, about 200 ·cor below, about 100 ·c
or below, at about 80 •c or below, at about 50 ·cor below, at about 45 •c
or below, at about 40 ·c or below, at about 35 ·c or below, at about 30 ·c
or below, at about 25 •c or below or at about 20 •c or below, and ranges
between and including any two of these values. In some embodiments, the
solid state polymerization is conducted at a temperature of about 50 •c to
about 400 ·c. about 80 ·c to about 350 •c, about 100 ·c to about 300 ·c,
about 150 ·c to about 250 •c, about 180 ·c to about 200 •c, and ranges
I
26
between and including any two of these values. The FR polyester can be
solid state polymerized for a time sufficient to increase its molecular
weight or IV to the desired value. For example, the solid state
polymerization reaction can be conducted for a period of about 1 min to
about 60 min, about 1 h to about 5 h, about 5 h to about 8 h, about 8 h to
about 15 h, about 15 h to about 25 h, about 25 h to about 40 h, and
ranges between and including any two of these values.
In some embodiments, dicarboxylic acid used in the methods of the
present invention are used in an amount ranging from about 0.01% to
about 99% by weight of the total weight of the flame retardant polyester.
This includes embodiments in which the amount ranges from about 10%
to about 99%, from about 20% to about 95%, from about 30% to about
92%, from about 40% to about 90 %, from about 50 % to about 80% and
from about 60% to about 75% of the total weight of the FR polyester
composition, and;ranges between any two of these values or less than any
one of these values. In some embodiments, the alkylene diol may
constitute from about 0.01 wt%, about 10 wt%, about 20 wt%, about 30
wt%, about 40 wt%, about 50 wt%, about 60 wt%, about 70 wt%, and
ranges between any two of these values or less than any one of these
values. In some embodiments, the flame retardant additives used is
ranging from about 0.01 wt%, about 4 wt%, about 8 wt%, about 10 wt%,
about 12 wt%, about 15 wt%, about 20 wt%, about 30 wt%, about 40 wt%,
about 50 wt%, about 60 wt%, about 70 wt%, about 80 wt%, and ranges
between any two of these values or less than any one of these values.
However, other amounts are possible. The particular amount depends
upon the desired properties of the polyester composition. In some
embodiments, the organic phosphonic acid includes about 0.01 wt% to
about 15 wt% of the flame retardant polyester masterbatch.
27
In one embodiment, the crystallized co-polyester is subjected to solid state
polymerization by placing the pelletized or pulverized polymer into a
tumble drier of an inert gas, such as nitrogen, or under a vacuum of 1 torr,
at an elevated temperature, above 150 •c but below the melting
temperature, for a period of about 4 to about 16 h. In some embodiments,
the solid state polymerization is carried out at a temperature of about 180
·c to about 200 ·c which results in an increase in inherent viscosity to
about 1 dl/g.
In another aspect, provided is a flame retardant polyethylene terephthalate
(FR PET) polyester masterbatch obtained by the method described herein.
The FR PET includes 30 to 90 wt% of one or more aromatic dicarboxylic
acid or ester thereof; and 10 to 70 wt% of one or more alkylene diol; 0 to
10 wt% of at least one phosphorus based flame retardant additive; one or
more reagents selected from the group consisting of liquid plasticizer in an
amount of 0.5 to 2 wt%; at least on~ nucleating agent in an amount of 10
ppm to 2000 ppm; at least one branching agent in an amount of 10 ppm to
2000 ppm; at least one anti-oxidizing agent in an amount ranging from 0.1
to 5 wt%; at least one stabilizing agent; at least one additive and
optionally, at least one end-capped oligomer in an amount of 1 to 20 wt%,
wherein the polyester has characterized by LOI having value greater than
25 (LOI>25).
In one aspect, the method further includes melt blending the FR polyester
masterbatch with normal polyamide or normal polyester, extruding a
filament, and spinning the filament into a fiber or yarn. In some
embodiments the FR polyester masterbatch can be melt blended with
normal nylon ('Target Polymer") or normal polyethylene terephthalate
("Target Polymer") in suitable amounts to adjust the Phosphorus content
of the polyester or polyamide composition with desired limiting oxygen
index (LOI). Suitable melt blending conditions are known in the art.
I
28
The FR polyester has an inherent viscosity of at least 0.250 dUg and
lower oligomer content less than 1.2 wt% after up gradation of intrinsic
viscosity in solid state polymerization. In one embodiment, the inherent
viscosity of the FR polyester is in the range of 0.30 to 0.50 dL!g. The FR
PET masterbatch can be blended with polyester or polyamides to extruded
and/or molded to fibers and other articles. The fibers obtained from
blending polyester (PET) have superior flame retardant property. The
fibers obtained from blending of FR polyester and nylons have improved
flame retardancy of the fiber.
In one aspect, provided are flame retardant polyesters which can be used
in fiber or yarn applications. The FR polyester includes at least one
polyester; and at least one flame retardant additive and optionally one or
more additives. The FR polyester is obtained from the polymerization
reaction of at least one dicarboxylic acid or ester fhereof, alkylene diol,
and phosphinic acid. The phosphorus based FR additive is preferably
added to the esterification reactor, after formation of oligomers or prepolymers,
for uniform distribution of the FR additive in the polyester chain.
The phosphinic acid is useful for obtaining the flame retardant polymer
include, but are not limited to, 2-Carboxyethyl(phenyl) phosphinic acid or
3-hydroxyphenylphosphinyl-propanoic acid), 9,1 0-dihydro-1 0-(2,3-
di(hydroxyl carbonyl) propyl] 1 0-phosphaphenanthrene-1 0-oxid, 2,2-
Bis(chloromethyl)trimethylene bis[bis (2-chloroethyl) Phosphate,
Chlorendic acid, tetrakis (2-chloroethyl) dichloroisopentyldiphosphate, Tris
(2-chloroethyl) phosphate, tris (1-chloro-2-propyl) phosphate, tris (2, 3-
dichloro-1-propyl) phosphate, hexachlorocyclopentadienyldibromocyclooctane,
tetrakis(2-chloroethyl)dichloroisopentyldiphosphate,
tris(2-chloroethyl) phosphate, Poly(2,6-dibromo-phenylene oxide), tetra-
1
29
decabromo-diphenoxy-benzene, 1 ,2-Bis(2,4,6-tribromo-phenoxy) ethane,
3,5,3,5-Tetrabromo-bisphenol A (TBBA),TBBA, unspecified, TBBAepichlorhydrin
oligomer, TBBA-TBBA-diglycidyl-ether oligomer, TBBA
carbonate oligomer, TBBA carbonate oligomer, phenoxy end capped,
TBBA carbonate oligomer, 2,4,6-tribromo-phenol terminated, TBBAbisphenol
A-phosgene polymer, brominated epoxy resin end-capped with
tribromophenol, TBBA-(2,3-dibromo-propyl-ether), TBBA bis-(2-hydroxyethyl-
ether), TBBA-bis-(allyl-ether), TBBA-dimethyl-ether, Tetrabromobisphenol
S, TBBS-bis-(2,3-dibromo-propyl-ether), 2,4-dibromo-phenol,
2,4,6-tribromo-phenol, pentabromo-phenol, 2,4,6-Tribromo-phenyl-allylether,
tribromo-phenyl-allyl-ether, bis(methyl)tetrabromo-phtalate, Bis(2-
ethylhexyl)tetrabromo-phtalate, 2-Hydroxy-propyl-2-(2-hydroxy-ethoxy)ethyi-
TBP, TBPA, glycol-and propylene-oxide esters, N,N-Ethylene -bis-
(tetrabromo-phthalimide), ethylene-bis(5,6-dibromo-norbornane-2,3-
dicarboximide), 2,3-Dibromo-2-butene-1 ,4-diol, Dibromo-neopentyl-glycol,
Dibromo-propanol, tribromocneopentyl-alcohol, poly tribromo-styrene, :and
combination thereof.
The alkylenediol used for obtaining the phosphorus containing polymer
include, but are not limited to, ethylene glycol, propanediol, butanediol,
cyclohexanedimethanol, hexane diol and combinations thereof. Suitable
additives useful for obtaining the FR polyester include, but are not limited
to, nucleating agent, branching agent, chain extender, antioxidant,
plasticizers, stabilizing agent etc.
In one aspect, provided is a crystallizable FR polyester masterbatch
containing greater than about 10 wt% phosphorus so that it can be
upgraded in solid state polymerization to required I.V. level and lower
oligomer contents.
30
In some embodiments, the polyester exhibits superior flame retardant
properties to polyester (PET). The FR polyester can be made by the melt
condensation method described above to have an inherent viscosity of at
least about 0.25 dl/g, and often as high as about 0.35 dl/g or greater,
without further treatment. The product made by melt polymerization, after
extruding, cooling, and pelletizing, is in amorphous state (non- crystalline).
The product can be made semi-crystalline by heating it to a temperature in
the range of about 110 oc to about 150 oc for an extended period of time
(about 4h to about 8 h). This induces crystallization so that the product can
then be heated up to below melting temperature of polyester to raise the
molecular weight and obtain the desired intrinsic viscosity.
Suitable coloring agents for use in fibers are known in the art and may
include, but are not limited to dyes, inorganic or organic pigments, or
mixtures of these. In some embodiments, the coloring agents include dyes
selected from the group consisting of azo, azomethine, methine,
anthraquinone, phthalocyanine, dioxazine, flavanthrone, indanthrone,
anthrapyrimidine and metal complex dyes. In one embodiment the coloring
agent is selected from the group consisting of metal oxides, mixed metal
oxides, metal sulfides, zinc ferrites, sodium alumino sulfo-silicate
pigments, carbon blacks, phthalocyanines, quinacridones, nickel azo
compounds, mono azo coloring agents, anthraquinones and perylenes. In
some embodiments, the coloring agent is selected from the group
consisting of Solvent Blue 132, Solvent Yellow 21, Solvent Red 225,
Solvent Red 214 and Solvent Violet 46, Carbon Black, Titanium Dioxide,
Zinc Sulfide, Zinc Oxide, Ultramarine Blue, Cobalt Aluminate, Iron Oxides,
Pigment Blue 15, Pigment Blue 60, Pigment Brown 24, Pigment Red 122,
Pigment Red 147, Pigment Red 149, Pigment Red 177, Pigment Red 178,
Pigment Red 179, Pigment Red 202, Pigment Red 272, Pigment Violet 19,
Pigment Violet 29, Pigment Green 7, Pigment Yellow 119, Pigment Yellow
147 and Pigment Yellow 150, or a combination thereof.
31
Depending on the desired color, any number of different coloring agents in
varying proportions may be used. In some embodiments, the coloring
agent may constitute from about 0.001 wt%, about 0.01 wt%, about 0.1
wt%, about 0.5 wt%, about 1 wt%, about 2 wt%, about 5 wt%, about 8
wt%, about 10 wt%, about 15 wt%, about 20 wt%, about 25 wt%, about 30
wt%, about 40 wt%, about 50 wt% of the total composition, and ranges
between any two of these values or less than any one of these values.
However, other amounts are possible. The particular amount depends
upon the desired color of the fiber composition. In some embodiments, the
composition includes about 0.01 wt% to about 10 wt% of the coloring
agent.
The flame retardant polyester and polymer compositions described herein
can be utilized for various applications. Typical end-use applications
include, but are not limited to, extruded and non-extruded fibers and yarns
for various applications such as for example, apparel fabric, drapery,
upholstery, wall coverings, heavy industrial fabrics, ropes, cords, shoe
laces, nettings, carpets and rugs.
In one aspect, there is provided a flame retardant polyester masterbatch
composition comprising: at least one dicarboxylic acid; at least one diol; up
to 10 wt.% of one or more flame-retardant additives or combination
thereof containing phosphorous atom, wherein the flame-retardant
additives is, but not limited to, 2-Carboxyethyl(phenyl) phosphinic acid or
3-(Hydroxyphenylphosphinyl) propanoic acid), 9,1 0-dihydro-1 0-[2,3-
di(hydroxyl carbonyl) propyl] 1 0-phosphaphenanthrene-1 0-oxide, or
combination thereof.
In some embodiments, 60-98 mol% of dicarboxylic acid is used in the
methods of the present invention. The dicarboxylic acid of this
32
embodiment is purified terephthalic acid (PTA) or dimethyl terephthalate
(DMT). In another embodiment, 2-40 mol% of dicarboxylic acid other than
the terephthalic acid can also be used. The dicarboxylic acid of this
embodiment is selected from the group consisting of isophthalic acid
(IPA), 2, 6-napthalene dicarboxylic acid (NDA), adipic acid, sebacic acid,
succinic acid, azelic acid etc.
In some embodiments, the diol used in the methods of the present
invention is mono ethylene glycol (MEG). Preferably, about 80 mol% to
about 99 mol% of mono ethylene glycol (MEG) is used as a glycol.
In one another aspect of the present invention, Post-Consumer Recycled
(PCR) PET flakes can be used as starting raw material instead using
PTA/DMT. In some embodiments, the recycling route can be mechanical
extrusion or glycolysis with required filtration scheme.
In some embodiments, the flame retardant used in the methods of the
present invention are 2-carboxyethyl (phenyl) phosphinic acid [also known
as 3-(hydroxyphenylphosphinyl) propanoic acid] and/or 9, 1 0-dihydro-1 0-
[2, 3-di (hydroxyl carbonyl) propyl] 1 0-phosphaphenanthrene-1 0-oxide or
combination thereof.
In some embodiments of the present invention, 2-carboxyethyl(phenyl)
phosphinic acid is used in an amount ranging from about 0:01 wt% to
about 10 wt%, about 5 wt% to 30 wt%, about 8 wt% to 50 wt%, about 12
wt% to 70 wt%, and ranges between and includes any two of these
values. The weight percent (wt%) is calculated based on the total weight
of the flame retardant polyester.
In some embodiments of the present invention, the flame retardant
polyester comprises up to about 60 wt. % of the flame retardant additive.
33
In a preferred embodiment the flame retardant is selected from the group
consisting of 2-carboxyethyl (phenyl) phosphinic in an amount from about
2 wt% to about 10 wt%, preferably up to 5 wt%, more preferably 2.5 wt%.
The weight percent is calculated based on the total weight of the flame
retardant polyester.
In some embodiments, 9,1 0-dihydro-1 0-[2,3-di(hydroxyl carbonyl) propyl]
10-phosphaphenanthrene-10-oxide is used in an amount up to 1 wt% to 5
wt%, preferably in amount of 2 wt%, more preferably in amount of 1.5
wt%.
The flame retardant additive reacts with monomer or other reactive end
groups of monomers, oligomers, or pre-polymers during esterification
process in the reactor. Thus the FR additive is uniformly distributed in the
polymer chain rendering permanent flame retardancy and enables better
processing of the polymer by extrusion blow moulding process. The other
polymeric properties will remain unaffected due to incorporation of the
flame retardant additive. The presence of additional functional group in the
phosphoric acid encourage reaction with oligomer, pre-polymers, and
unreacted monomers.
In some embodiments, there can be incorporated some co-monomers e.g.
isophthalic acid, or plasticizers for easy dispersibilty of masterbatch. In
some embodiments, there can be added multifunctional additive e.g.
maleic anhydride.
In some embodiments, the phosphorous content in the flame retardant
polyester masterbatch can be achieved up to about 60,000 ppm, up to
about 45,000 ppm, up to about 30,000 ppm up to about 15,000 ppm,
preferably up to about 10,000 ppm, preferably about up to 5,000 ppm,
34
preferably up to about 1000 ppm, or in any range falling between above
value.
In some embodiments, the flame retardant polyester can be melt blended,
in required proportion, with target polymers e.g. PET, PEN, PBT, PTT,
PBN, Nylon, or polypropylene for further extrusion or spinning purposes.
The phosphorus content in the target polymer can be adjusted by
controlled use of FR PET masterbatch in a manner so as to achieve the
required level of Low Limiting Oxygen Index (LOI).
In some embodiments of the present invention there can be incorporated
some compatibilizers e.g. SIP A, DMSIP.
In some embodiments the flame retardant additive can be added before,
during or after esterification reaction in the reactor. In some embodiments
the flame retardant additive can be added before, during or after
polymerization reaction. In a preferred embodiment the flame retardant
additive is added after esterification and before polymerization reaction in
the esterification reactor. In some embodiments the flame retardant
additive reacts with monomers, oligomers or pre-polymers in the
esterification reactor.
In some embodiments the FR polyethylene terephthalate masterbatch is
preferably used to impart permanent flame retarding properties in carpet,
textiles, fibers, yarns, and sheets comprising polyester or nylon.
In melt phase polymerization polymer granules of I.V. up to 0.40 to 0.50
dUgm can be manufactured that further can be upgraded solid state
polymerization to get the required intrinsic viscosity (I.V.). The polyester
masterbatch produced in this manner have improved flame retardant
35
properties, good color (L * > 55%, a* of -1.0 & b* of -1.0), transparency and
good processability.
The polyester masterbatch obtained from use of such phosphorous based
additives shows the improved properties, e.g. high crystallinity, low
moisture contents, low oligomer contents, high glass transition
temperature (T9) and high melting point (T ml· Such masterbatch gives
flexibility of inventory management whereby-it can be incorporated in any
PET chips (super bright, semi-dull, full-dull, etc.) and RPET; it can also be
used in film & sheets. The contents of phosphorous used in the PET can
be varied as per the requirement.
The flame-retardant polyester obtained in accordance to the process of
the present disclosure also meets the health, safety and recycling
standards in textile and packaging industry. Moreover, the polyester
cpmposition contains reactive flame retardants which makes the polyester
thermally stable due to permanent bonding between the flame-retardant
comonomer and the polyester. Such modified flame-retardant PET grades
have permanent FR properties which are not lost on washing.
The products manufactured from the flame retardant polyester
masterbatch can be blended with PET or RPET including other polymers
in textile, wires, cables, consumer electronic housings, office electronics
housing, printed circuit boards, appliances, applications, vehicle seats, in
electrical engineering and electronics, carpet, flooring, thermal insulation
for roofs, facades, walls, dueling and conduit etc. The polyester
masterbatch is preferably used in textile applications.
The present invention, thus generally described, will be understood more
readily by reference to the following examples, which are provided by way
of. illustration and are not intended to be limiting of the present invention.
I . . . .
36
Quality Parameters
In the examples below as well as throughout the application, the following
abbreviations have the following meanings. If not defined, the terms have
their generally accepted meanings.
PET: Polyethylene terephthalate,
PTA: Purified terephthalic acid,
PCR: Post-consumer recycled,
MEG: Mono ethylene glycol,
DEG: Diethylene glycol,
N.A.: Nucleating Agent,
PBT: Polybutylene terephthalate,
PTN: Polytrimethylene terephthalate,
SSP: ;solid state polymerization,
dUgm: deciliters per gram,
megfkg: mill equivalentsfkilogram,
wt %: weight percentage,
I.V.: intrinsic viscosity,
T9: glass transition temperature,
Tch: crystallization temperature,
T m: melting temperature
LOI: Limiting Oxygen Index
FR: Flame Retardant
FR PET: Flame retardant polyester
FR Polyester: Flame retardant polyester
Intrinsic Viscosity
37
Intrinsic viscosity (I.V.) is a measure of the molecular mass of the polymer
and is measured by dilute solution using an Ubbelohde viscometer. All
intrinsic viscosities are measured in a 60:40 mixture of phenol and stetrachloroethane
with 0.5 % concentration. The flow time of solvent and
solution are checked under I.V. water bath maintained at temperature bout
25 oc. The I.V., 1'], was obtained from the measurement of relative
viscosity, 11r, for a single polymer concentration by using the Billmeyer
equation:
IV= I'll= 0.25[(RV-1) + 3 In RV] I c
Wherein 11 is the intrinsic viscosity, RV is the relative viscosity; and c is the
concentration of the polymeric solution (in g/dl). The relative viscosity
(RV) is obtained from the ratio between the flow times of the solution (!)
and the flow time of the pure solvent mixture (10).
RV = n,.1 = Flow time of solution (!) I Flow time of solvent (10)
I.V. must be controlled so that pro~ss ability and end properties of a
polymer remain in the desired range.' Class 'A' certified burette being used
for IV measurement for more accuracy.
Color
The color parameters were measured with a Hunter Lab Ultrascan VIS
instrument. 065 illuminant and 1 oo angle is being used for color
measurement. Both Amorphous and Solid State Polymerized (SSP) were
used to check by reflectance mode of Hunter Color Scan. Generally, the
changes measured could also be seen by eyes. The color of the
transparent amorphous/SSP chips was categorized using the Hunter
Scale (L I a I b) & CIE Scale (L *I a* I b*) values which are based on the
Opponent-Color Theory. This theory assumes that the receptors in the
human eyes perceive color as the following pairs of opposites.
• L I L *scale: Light vs. Dark where a low number (0-50) indicates
dark and a high number (51~100) indicates li~ht.
38
• a I a* scale: Red vs. Green where a positive number indicates
red and a negative number indicates green.
• bib* scale: Yellow vs. Blue where a positive number indicates
yellow and a negative number indicates blue.
The L * values after SSP are higher because of whitening caused by
spherulitic crystallization of the polymer.
DEGIEGIIPA/800 content:
To determine the diethylene glycol (DEG), ethylene glycol (EG),
isophthalic acid (IPA) and butanediol (BOO) in the modified polyester,
polymer sample is trans-esterified with methanol in an autoclave at 200 •c
temperature for 2.5 hours with zinc acetate as a catalyst.
During methanolysis, the polymer sample is depolymerized and the liquid
I
is filter through Whatman 42 filter paper. After filtratiofl\ 1 micro liter of the
liquid was injected in Agilent Gas Chromatography (GC) under.controlled
GC configuration. Based on the RT (Retention Time), DEG I EG I
IPA/BDO are calculated with Internal Standard ISTD (tetraethylene glycol
dimethyl ether) and results are declared as wt. %.
COOH End groups:
The Polymer was dissolved in a mixture of phenol and chloroform (50: 50 wlv)
under reflux conditions. After cooling to room temperature, the COOH end
groups were determined using titration against 0.025 N Benzyl alcoholic KOH
solution with bromophenol blue as an indicator. Run a blank simultaneously
along with sample and the final end point is at the color change from blue from
yellow. COOH groups are calculated based on the below calculation and the
results are expressed in meq of COOHikg. In the equation, TR is the volume
of benzyl alcoholic KOH consumed for the sample, N is the normality of benzyl
alcoholic KOH, and the blank is the volume of benzyl alcoholic KOH consumed
I
39
for sample solution.
[(TR- Blank) x N x 1 000] = COOH end groups (meq/kg)
DSC analysis
The Differential Scanning Calorimeter (DSC) is a thermal analyzer which
can accurately and quickly determine the thermal behavior of Polymers
such as glass transition temperatures (T9), crystallization exothermic peak
temperatures (Tch). peak endotherm temperatures (T m). heats of
crystallization (LI.H) and heats of fusion for all materials. A Perkin-Elmer
model Jade DSC was used to monitor thermal properties of all polymer
samples at heating and cooling rates of 10 oc per minute. A nitrogen
purge was utilized to prevent oxidation degradation.
Crystallinity by DSC and DGC:
The Differential Scanning Calorimeter · (DSC) and Density Gradient
Column (DGC) are used to calculate the crystallinity of polymer samples. :
By DSC, the crystallinity is calculated by heat of fusion ((LI.H) of Tm1 (Heat
1 cycle) with specific heat of polymer.
By DGC (Density Gradient Column), the crystallinity is calculated with the
help of known standard balls floating at the Lloyds densitometer.
Oligomer Content:
The ol~gomer content in the polymer samples was determined by Soxhlet
reflux methods. Polymer samples were refluxed with 1, 4-dioxane for 2
hours in a mantle heater. After 2 hours, the refluxed sample is filtered
through Whatmann 42 filter paper and the filtrate was transferred to a
clean, dry, pre-weighed 100 ml glass beaker. The filtrate was then heated
to dryness on a hot plate at 180°C. After drying, the beaker was kept in an
40
air oven at 140oc for 30 minutes. Finally, the oligomer content wt. %) was
calculated according to the following:
{[(Beaker with Residue (g))- (Empty Beaker (g))]/ sample weight (g)} x
100.
The following examples are given for the purpose of illustrating various
embodiments of the invention and are not meant to limit the present
invention in any fashion. The present examples, along with the methods
described herein are presently representative of preferred embodiments,
are exemplary, and are not intended as limitations on the scope of the
invention. Changes therein and other uses which are encompassed within
the spirit of the invention as defined by the scope of the claims will occur
to those skilled in the art.
Examples
The following examples are given for the purpose of illustrating various
embodiments of the invention and are not meant to limit the present
invention in any fashion. The present examples, along with the methods
described herein are presently representative of preferred embodiments,
are exemplary, and are not intended as limitations on the scope of the
invention. Changes therein and other uses which are encompassed within
the spirit of the invention as defined by the scope of the claims will occur
to those skilled in the art. The flame retardant polyester is generally
prepared from a process comprising following four steps.
Step 1: Preparation of Raw Material Slurry: A slurry of pure terephthalic
acid {PTA) and ethylene glycol (MEG) in the ratio of about 70:30 wt. %
was prepared in a- paste preparation vessel along with the required
concentration of sodium acetate anhydrous and of pentaerythritol. The
polymerization catalysts, e.g. antimony trioxide (Sb20 3), germanium oxide
(Ge02), was added to the paste preparation vessel along with Cobalt
Acetate (CoAc) as a color toner along with additional red and/or blue
toners if required in the range up to 40 ppm.
41
Step 2: Esterification Process: An esterification reactor equipped with
agitator, internal heating coils, and external heating limpet coils. The
esterification reaction is maintained under the inert atmosphere by
nitrogen supplied through a separate system attached to the reactor. The
reaction is, as known in the art, carried out under pressure in the range of
2 to 3.5 kgfcm2 and at the temperature ranging from 260 °C to 285 °C for
4 to 5 hours.
The slurry made in step 1 was transferred into the esterification reactor
and the esterification reaction was carried out at temperature between 240
to 260 °C, under 3 kg nitrogen pressures. The esterification reaction
results to the formation of diester, e. g. bis (2-hydroxyethyl) terephthalate
including other low molecular weight esters. The low molecular
compounds, e.g. low oligomers, have the degree of polymerization (DP)
between 5 to 10.
Byproducts, e.g. water or alkanol, formed during the esterification reaction
was separated so as to push forward the reaction.
Step 3: Polycondensation Reaction: Like the esterification reactor, the
polycondensation reactor used in the process is also equipped with an
agitator, external heating, limpet coils, condenser and fine vacuum
system. Polymerization was processed by gradually reducing the pressure
from 5 to 20 mbar and increasing the temperature from 260 °C to 285 °C.
The polymerization takes place in the presence of one more catalysts or
combination thereof. During the polymerization reaction various oligomers
react each other leading to larger molecules with increased degree of
polymerisation (DP) of 150-170 under low pressure up to 0.2 mbar and at
temperature about 245 °C to 288 °C. The polycondensation reaction was
monitored based on agitator's power consumption, and subsequently the
42
1- •.• -·
reaction was terminated once the intrinsic viscosity (I.V.) is achieved about
0.62 dUgm. eventually, the molten polymer was extruded out as strands
and cut under the cold water and collected as amorphous chips.
Step 4: Solid state polymerization: The amorphous chips obtained from
the above step 3, were crystallized to obtain the crystallized polymer at a
temperature about 120 °C to 150 °C for an extended period of time (about
2 to about 6 hours) in tumble drier. The crystallized polymer was further
subjected to solid state polymerization (SSP) in the same tumble drier
against the inert gas current, usually nitrogen, or under a vacuum of 1
Torr, at an elevated temperature about 150 °C, but below the melting
temperature, for a period of about 4 to about 16 hours. The solid state
polymerization was preferably carried out at temperature about 190 °C to
about 210 °C. The SSP, in results, increases the inherent viscosity level of
the polymer up to about 0.95 dUg or higher.
Example 1: preparation of flame retardant polyethylene terephthalate
polyester
In an esterification reactor equipped with a stirrer, condenser, pressurizing
and vacuum system, 8.66 kg of PTA and 3.75 kg of MEG in molar ratio
1:1.16 for a 15 kg batch size were made into a paste and fed into the
esterification reactor for charging. In addition, 60 ppm of sodium acetate
anhydrous, 700 ppm of pentaerythritol, 7.17 gm (400ppm as Sb) of
antimony trioxide catalyst, 0.65 gm (30 ppm as Ge) Ge02 catalyst, 2.53
gm (40 ppm as Co) of Cobalt Acetate powder were added to the
esterification reactor. Esterification was carried out at temperature ranging
from about 240°C to 260°C. Subsequently, 2.69 gm (50 ppm as P) of
orthophosphoric acid and 2.60 gm (2.5 wt %) of 2-Carboxyethyl(phenyl)
phosphinic acid were added to the esterified resin, and the reaction
mixture was kept on hold for half an hours at a temperature between 252
43
to 255 oc and then 4.59 gm (1.5 wt. %) of 9,1 0-dihydro-1 0-[2,3-di(hydroxyl
carbonyl) propyl] 1 0-phosphaphenanthrene-1 0-oxide to obtain prepolymers.
The pre-polymers formed along with all the additives was
transferred to the polycondensation reactor through 10 micron filter, and
the polymerization of the pre-polymers was conducted at temperature
ranging from about 270 oc and 285°C with a peak temperature of 284° C.
The polycondensation reaction was monitored based on reactor agitator
power consumption and the reaction was terminated to get I.V. of about
0.62 dUgm, the melt polyester resin was extruded out as strands,
quenched under cold water, and cut into amorphous chips. These
amorphous chips were then dried and pre-crystallized before subjecting to
solid state polymerization (SSP) for increasing the I.V. up to 0.95 dl/gm.
Example 2: preparation of flame retardant polyethylene terephthalate
polyester
A paste of 9.75 kg of PTA and 4.23 kg of MEG, in molar ratio 1:1.16, was
fed into an esterification reactor equipped with a stirrer, condenser,
pressurizing and vacuum system. Then, 60 ppm of sodium acetate
anhydrous, 700 ppm of pentaerythritol, 7.17 gm (400ppm as Sb) of
antimony trioxide catalyst, 0.65 gm (30 ppm as Ge) Ge02 catalyst, 2.53
gm (40 ppm as Co) of Cobalt Acetate powder were added to the
esterification reactor. Subsequently the esterification was carried out at
temperature ranging from about 240 oc and 260 °C. After esterification
when some oligomers, pre-polymers are formed, 2.69 gm (50 ppm as P)
of orthophosphoric acid and 4.17 gm (4 wt %) of 2-Carboxyethyl(phenyl)
phosphinic acid was added to the esterified resin and kept the reaction
mixture on hold for half an hours at a temperature between 252 to 255 °C,
thereafter the pre-polymers including the additives was transferred to the
polycoridensation reactor through 10 micron filter for polymerization
conducted at temperature between 270 and 285°C with a peak
44
temperature of 284° C. The polycondensation reaction was monitored
based on reactor agitator power consumption and reaction was terminated
to get I.V of about 0.62 dUgm, the amorphous polyester resin melt was
extruded out as strands, quenched under cold water and cut under water
into chips. These amorphous chips were further dried and pre-crystallized
before subjecting them to solid state polymerization (SSP) for increasing
the I.V up to 0.95 dl/gm.
Example 3: preparation of flame retardant polyethylene terephthalate
polyester
To an esterification reactor equipped with a stirrer, condenser,
pressurizing and vacuum system, 7.85 kg of pure terephthalic acid (PTA)
and 3.40 kg of monoethylene glycol (MEG) for a 15 kg of FR PET batch
were made into a paste and then fed into the esterification reactor. The
molar ratio of PTA: MEG is 1:1.16. Further, 7.17 gm (400ppm as Sb) of
antimony trioxide catalyst, 0.65 gm (30 ppm as Ge) Ge02 catalyst, 2.53
gm (40 ppm as Co) of Cobalt Acetate powder, 60 ppm of sodium acetate
anhydrous and 700 ppm of pentaerythritol calculated on the basis of 15kg
FR PET, were added to the esterification reactor. Thereafter esterification
was carried out at temperature between about 240 to 260° C to obtain the
low molecular weight pre-polymers/oligomers. The prepolymers/
oligomers then, reacted with 2.69 gm (50 ppm as P) of
orthophosphoric acid and 3.65 gm (3.5 wt %) of 2-Carboxyethyl(phenyl)
phosphinic acid in the esterification reactor to obtain the esterified resin,
then the reaction mixture was kept on hold for about half an hours at a
temperature between about 252 to 255 oc and then 4.59 gm (1.5 wt%) of
9,1 0-dihydro-1 0-[2,3-di(hydroxyl carbonyl) propyl] 10-
phosphaphenanthrene-1 0-oxide added to the reaction mixture. The
reaction mixture comprising pre-polymers was transferred via a 10 micron
filter to the polycondensation reactor for polymerization thereof. The
45
polymerization was conducted at temperature about 270 oc to about
285°C. with a peak temperature of 284° C. The polycondensation reaction
was monitored based on reactor agitator power consumption and reaction
was terminated as the IV reaches about 0.6 dl/gm, the amorphous melt
polyester resin so obtained was extruded out as strands and cut under
cold water to get amorphous chips. These amorphous chips were then
dried and pre-crystallized before subjecting to solid state polymerization
(SSP) for increasing the I.V up to 0.95 dUgm.
Example 4: preparation of flame retardant polyethylene terephthalate
polyester
In an esterification reactor equipped with a stirrer, condenser, pressurizing
and vacuum system, 154.5 kg of PTA, 50 kg of IPA, and 80.5 kg of MEG
in molar ratio 1:1.16 for a 15 kg batch size were made into a paste and fed
illto the esterification reactor for charging. In addition, 60 ppm of sodium
icetate anhydrous, 700 ppm of pentaerythritol, 7.17 gm (400ppm as Sb)
of antimony trioxide catalyst, 0.65 gm (30 ppm as Ge) Ge02 catalyst, 2.53
gm (40 ppm as Co) of Cobalt Acetate powder were added to the
esterification reactor. Esterification was carried out at temperature ranging
from about 240°C to 260°C. Subsequently, 2.69 gm (50 ppm as P) of
orthophosphoric acid and 57.5 kg of 2-Carboxyethyl(phenyl) phosphinic
acid were added to the esterified resin, and the reaction mixture was kept
on hold for half an hours at a temperature between 252 to 255 oc and then
383.3 kg of 9,10-dihydro-10-[2,3-di(hydroxyl carbonyl) propyl] 10-
phosphaphenanthrene-1 0-oxide to obtain pre-polymers. The pre-polymers
formed along with all the additives was transferred to the
polycondensation reactor through 10 micron filter, and the polymerization
of the pre-polymers was conducted at temperature ranging from about 270
oc and 285°C with a peak temperature of 284° C. The polycondensation
reaction was monitored based on reactor agitator power consumption and
I
46
the reaction was terminated to get I.V. of about 0.58 dllgm, the melt
polyester resin was extruded out as strands, quenched under cold water,
and cut into amorphous chips. These amorphous chips were then dried
and pre-crystallized before subjecting to solid state polymerization (SSP)
for increasing the I.V. up to 0.95 dllgm.
Example 5: preparation of flame retardant polyethylene terephthalate
In an esterification reactor equipped with a stirrer, condenser, pressurizing
and vacuum system, 76.75 kg of PTA, 25 kg of IPA, and 40 kg of MEG in
molar ratio 1 :1.16 for a 15 kg batch size were made into a paste and fed
into the esterification reactor for charging. In addition, 60 ppm of sodium
acetate anhydrous, 700 ppm of pentaerythritol, 7.17 gm (400ppm as Sb)
of antimony trioxide catalyst, 0.65 gm (30 ppm as Ge) Ge02 catalyst, 2.53
gm (40 ppm as Co) of Cobalt Acetate powder were added to the
esterification reactqr. Esterification was carried out at temperature ranging
I from about 24o•c to 26o·c. Subsequently, 2.69 gm (50 ppm as P) of
orthophosphoric acid and 28.75 kg of 2-Carboxyethyl(phenyl) phosphinic
acid were added to the esterified resin, and the reaction mixture was kept
on hold for half an hours at a temperature between 252 to 255 •c and then
191 kg of 9,1 0-dihydro-1 0-[2,3-di(hydroxyl carbonyl) propyl] 10-
phosphaphenanthrene-1 0-oxide to obtain pre-polymers. The pre-polymers
formed along with all the additives was transferred to the
polycondensation reactor through 10 micron filter, and the polymerization
of the pre-polymers was conducted at temperature ranging from about 270
•c and 285°C with a peak temperature of 284• C. The polycondensation
reaction was monitored based on reactor agitator power consumption and
the reaction was terminated to get I.V. of about 0.59 dllgm, the melt
polyester resin was extruded out as strands, quenched under cold water,
and cut into amorphous chips. These amorphous chips were then dried
47
and pre-crystallized before subjecting to solid state polymerization (SSP)
for increasing the I.V. up to 0.95 dl/gm.
Raw Material (s) Example 1 Example 2 Example 3 Example4 Example 5
PTA (kgs) 8.66 9.75 7.85 153.5 76.75
IPA ( kgs) Nil Nil Nil 50/9.5% 25/9.5%
EG(kgs) 3.75 4.23 3.4 80.5 40
Sb (ppm) 400 400 400 400 400
Co(ppm) 40 40 40 40 40
Ge (ppm) 30 30 30 30 30
P (ppm) 50 50 50 50 50
Sodium acetate
60 60 60 anhydrous (ppm) 60 60
Pentaerythritol 700 700 700 700 700
AD01* 2.60 kg 4.17 kg 3.65 57.5 28.75
ADOZ* 4.59 kg - 4.59 kg 383.3 191
Physical Properties of Amorphous Polyester
I.V.(dUgm) 0.663 0.558 0.468 0.586 0.595
Ecooh (meqlkg) 60 112 115 36 33
Color L* 47.7 54 ' 42.4 33.5 34.1
Color a* -3.3 -1.3 2 -1.3 -1.6
Color b* 18 22.9 22 6.5 6.8
DEGwt% 2.85 5.85 4.22 5.82 5.32
IPAwt% Nil Nil Nil 9.46 9.48
rg c·c) 55.3 - - 52.3 53.1
P Content (ppm) 38557 39,176 50,104 51,035 50,918
The embodiments herein and the various features and advantageous
details thereof are explained with reference to the non-limiting
embodiments in the description. Descriptions of well-known components
and processing techniques are omitted so as to not unnecessarily obscure
the embodiments herein. The examples used herein are intended merely
to facilitate an understanding of ways in which the embodiments herein
may be practiced and to further enable those of skill in the art to practice
the embodiments herein. Accordingly, the examples should not be
construed as limiting the scope of the embodiments herein.
I
48
The foregoing de~:;.cription pf the specific embodiments will so fully reveal
~f.:~~..,,_~--~~-:-~--.:·~-,--;..--_---. . . . .
the general nature of the embodiments herein that others can, by applying
current knowledge, readily modify and/or adapt for various applications
such specific embodiments without departing from the generic concept,
and, therefore, such adaptations and modifications should and are
intended to be comprehended within the meaning and range of
equivalents of the disclosed embodiments. It is to be understood that the
phraseology or terminology employed herein is for the purpose of
description and not of limitation. Therefore, while the embodiments herein
have been described in terms of preferred embodiments, those skilled in
the art will recognize that the embodiments herein can be practiced with
modification within the spirit and scope of the embodiments as described
herein.
The use of the expression "at least" or "at least one" s:uggests the use of
one or more elements or ingredients or quantities, as the use may be in
the embodiment of the disclosure to achieve one or more of the desired
objects or results.
Any discussion of documents, acts, materials, devices, articles and the like
that has been included in this specification is solely for the purpose of
providing a context for the disclosure. li is not to be taken as an admission
that any or all of these matters form a part of the prior art base or were
common general knowledge in the field relevant to the disclosure as it
existed anywhere before the priority date of this application.
While considerable emphasis has been placed herein on the particular
features of this disclosure, it will be appreciated that various modifications
can be made, and that many changes can be made in the preferred
embodiments without departing from the principles of the disclosure.
I
49
These and other modifications in the nature of the disclosure or the
preferred embodiments will be apparent to those skilled in the art from the
disclosure herein, whereby it is to be distinctly understood that the
foregoing descriptive matter is to be interpreted merely as illustrative of the
disclosure and not as a limitation.

We Claim:
1. A method of preparing a polyester masterbatch composition with reactive
phosphorus based additive comprising:
a. preparing oligomers or pre-polymers comprising one or more
monomers;
b. reacting the said oligomers, the said pre-polymers, and unreacted
monomers with one or more additives and one or more phosphorus
(P) based flame retardant additive so as to achieve up to 60,000 PPM
phosphorus (P) in final reaction product, wherein the at least one
phosphorus based flame retardant additive is Carboxyalkyl(phenyl)
phosphinic acid;
c. melt polymerizing the said reaction product to obtain amorphous
polyester, and further crystallizing the said amorphous polyester in a
rotary or fluid bed crystalizer;
d. subsequently, subjecting the said crystalized amorphous polyester
chips of lower I.V. to solid state polymerization in batch or continuous
solid state polymerizer to obtain the said polyester masterbatch of high
intrinsic viscosity
2. The method as claimed in claim 1, wherein the said monomers are aliphatic or
aromatic dicarboxylic acids or ester thereof, and diols.
3. The method as claimed in claim 2, wherein the said dicarboxylic acid is
selected from the group consisting of terephthalic acid, dimethyl
terephthalate, isophthalic acid, dimethyl isophthalate, 2,6-napthalene
dicarboxylic acid, dimethyl-2,6-naphthalate, 2, 7 -naphthalenedicarboxylic
acid, dimethyl-2, 7-naphthalate, 3,4'-diphenyl ether dicarboxylic acid,
dimethyl-4,4'-methylenebis(benzoate), oxalic acid, dimethyl oxalate,
malonic acid, dimethyl malonate, succipic acid, dimethyl succinate,
methylsuccinic acid, glutaric acid, dimethyl glutarate, 2-methylglutaric
acid, 3-methylglutaric acid, adipic acid, dimjthyl adipate, 3-methyladipic
_;{I
acid, 2,2,5,5-tetramethylhexanedioic acid, pimelic acid, suberic acid,
azelaic acid, dimethyl azelate, sebacic acid, 1,11-
undecanedicarboxylic acid, 1,1 0-decanedicarboxylic acid,
undecanedioic acid, 1, 12-dodecanedicarboxylic acid, hexadecanedioic acid,
docosanedioic acid, tetracosanedioic acid, dimer acid, 1,4-
cyclohexanedicarboxylic acid, dimethyl-1 ,4-cyclohexanedicarboxylate,
1 ,3-cyclohexanedicarboxylic acid, dimethyl-1 ,3-
cyclohexanedicarboxylate, 1, 1-cyclohexanediacetic acid, metal salts of 5-
sulfo-dimethylisophalate, fumaric acid, maleic anhydride, maleic acid,
hexahydrophthalic acid and phthalic acid.
4. The method as claimed in claim 2, wherein the diol is selected from the
group consisting of ethylene glycol (MEG), diethylene glycol (DEG), 1,3-
propanediol, 1,4- butanediol, 1 ,6-hexanediol, 1 ,8-octanediol, 1,10-
decanediol, 1, 12-dodecanediol, 1, 14-tetradecanediol, 1, 16-hexadecanediol,
dimer diol, 1 ,4-cyclohexanedimethanol, di (ethylene glycol), tri (ethylene
glycol), poly (ethylene ether) glycols, poly (butylene ether) glycols,
branched diols, isosorbide, (cis, trans)1 ,3-cyclohexanedimethanol and (cis,
trans) 1,4 cyclohexanedimethanol.
5. The method as claimed in claim 4, wherein said branched diol is selected
from C4-C16 aliphatic branched diols from the group consisting of 2-
methyl-1 ,3-propanediol, 2,2-dimethyl-1 ,3-propanediol, 2-butyr-2-ethyl-1 ,3-
propanediol arid trimethylpentanediol. l
6. The method as claimed in claim 1, wherein the said additive is a nucleating
agent comprising inorganic or organic nucleating agent.
7. The method as claimed in claim 6, wherein the said inorganic nucleating
agent is at least one selected from the group consisting of calcium silicate,
nano silica powder, talc, Microtalc, Aclyn, kaolinite, montmorillonite, synthetic
mica, calcium sulfide, boron nitride, barium sulfate, aluminum oxide,
neodymium oxide and a metal salt of phenyl phosphonate.
8. The method as claimed in claim 6, wherein the said organic nucleating agent
is at least one selected from the group consisting of carboxylic acid metal
salts such as sodium benzoate, potassium benzoate, lithium benzoate,
calcium benzoate, magnesium benzoate, barium benzoate, lithium
terephthalate, sodium terephthalate, potassium terephthalate, calcium
oxalate, sodium laurate, potassium laurate, sodium myristate, potassium
myristate, calcium myristate, sodium octacosanoate, calcium octacosanoate,
sodium stearate, potassium stearate, lithium stearate, calcium stearate,
magnesium stearate, barium stearate, sodium montanate, calcium montanate,
sodium toluoylate, sodium salicylate, potassium salicylate, zin9 salicylate,
aluminum dibenzoate, potassium dibenzoate, lithium dibenzoate, sodium 13-
naphthalate and sodium cyclohexane carboxylate, organic sulfonates such as
sodium p-toluene sulfonate and sodium sulfoisophthalate, carboxylic acid
amides such as stearic acid amide, ethylene bislauric acid amide, palmitic
acid amide, hydroxystearic acid amide, erucic acid amide and tris(tbutylamide)
trimesate, phosphoric compound metal salts such as benzylidene
sorbitol and derivatives thereof, and sodium-2,2'-methylenebis(4,6-di-tbutylphenyl)
phosphate; and 2,2-methylbis(4,6-di+
butylphenyl) sodium.
9. The method as claimed in claim 6, wherein the said nucleating agent is
selected from the group consisting of oligomers such as PET, PBT, PIT,
PTN, PBN or PEl.
10. The method as claimed in claim 1, wherein the said flame retardant is
selected from the group consisting of 2-Carboxyethyl(phenyl) phosphinic
acid or 3- hydroxyphenylphosphinyl-propanoic acid), 9, 10-dihydro-1 0-[2,3-
di(hydroxylcarbonyl)propyl]1 0-phosphaphenanthrene-1 0-oxide, 2,2-
Bis(chloromethyl)trimethylene bis[bis(2-chloroethyl)] Phosphate, Chlorendic
acid, tetrakis(2-chloroethyl)dichloroisopentyldiphosphate, Tris(2-
chloroethyl)phosphate, tris(1-chloro-2-propyl)phosphate, tris(2,3-dichloro-1-
propyl)phosphate,
hexachlorocyclopentadienyl-dibromocyclooctane,
tetrakis(2-chloroethyl)dichloroisopentyldiphosphate, tris(2-
chloroethyl)phosphate, Poly(2,6-dibromo-phenylene oxide), tetra-decabromodiphenoxy-
benzene, 1 ,2-Bis(2,4,6-tribroryio-phenoxy) ethane, 3,5,3,5-
Tetrabromo-bisphenol A (TBBA), TBBA unspecified, TBBA-epichlorhydrin
oligomer, TBBA-TBBA-diglycidyl-ether oligomer, TBBA carbonate oligomer,
TBBA carbonate oligomer, phenoxy end capped, TBBA carbonate oligomer,
2,4,6-tribromo-phenol terminated, TBBA-bisphenol A-phosgene polymer,
brominated epoxy resin end-capped with tribromophenol, TBBA-(2,3-
dibromo-propyl-ether), TBBA bis-(2-hydroxy-ethyl-ether), TBBA-bis(
allyl-ether), TBBA-dimethyl-ether, Tetrabromo-bisphenol S, TBBS-bis-(2,3-
dibromo-propyl-ether), 2,4-dibromo-phenol, 2,4,6-tribromo-phenol,
pentabromo-phenol, 2,4,6-Tribromo-phenyl-allyl-ether, tribromo-phenyl-allylether,
bis(methyl)tetrabromo-phthalate, Bis(2-ethylhexyl)tetrabromo-phtalate,
2-Hydroxy-propyl-2-(2-hydroxy-ethoxy)-ethyl-TBP, TBPA, glycol and
propylene-oxide esters, N,N-Ethylene-bis-(tetrabromo-phthalimide),
ethylene-bis(5,6-dibromo-norbornane-2,3-dicarboximide), 2,3-Dibromo-2-
butene-1 ,4-diol, Dibromo-neopentyl-glycol,
Dibromo-propanol, tribromo-neopentyl-alcohol, poly tribromo-styrene and
combination thereof.
11. The method as claimed in claim 10, wherein the flame retardant preferably is
2-carboxyethyl (phenyl) phosphinic acid or 9,1 0-dihydro-1 0-[2,3-di (hydroxyl
carbonyl) propyl]1 0-phosphaphenanthrene-1 0-oxide or combination thereof.
12. The method as claimed in claim 1, wherein the said one or more additives,
other than FR additives, is sodium acetate anhydrous in an amount up to 100
ppm and preferably 60 ppm.
13. The method as claimed in claim 1, wherein one or more additives, other than
FR additives, is preferably pentaerythritol in an amount up to 1000 ppm and
preferably 700 ppm.
14. The method as claimed in claim 1, wherein the said polyester masterbatch
optionally comprising miscellaneous excipients such as polycondensation
catalysts or other additives.
15. The method as claimed in claim 1, wherein the polyester can be blended with
normal polymers subsequently extruded to yarns or fibers.
16. The method as claimed in claim 1, wherein the polyester is selected from the
group consisting of PET, PBT, PTI, PTN, PBN, PEl.
17.A flame retardant polymer composition comprising:
a. at least one dicarboxylic acid;
b. at least one diol;
c. one or more flame-retardant additives or combination thereof in an
amount sufficient to get up to 60;000 ppm phosphorus in the said
polymer;
d. one or more additives or mixture other than flame-retardant
additives thereof in an amount up to about 2000 ppm
18. The composition as claimed in claim 17, wherein the said composition is
phosphorus based polyethylene terephthalate (PET) polyester composition.
19. The composition as claimed in claim 17, wherein the said dicarboxylic acid is
aliphatic or aromatic acid.
20. The composition as claimed in claim 17, wherein the said dicarboxylic acid is
selected from the group consisting of terephthalic acid, dimethyl
terephthalate, isophthalic acid, dimethyl isophthalate, 2,6-napthalene
dicarboxylic acid, dimethyl-2,6-naphthalate, 2, 7 -naphthalenedicarboxylic
acid, dimethyl-2, 7-naphthalate, 3,4'-diphenyl ether dicarboxylic acid,
dimethyl-4,4'-methylenebis(benzoate), oxalic acid, dimethyl oxalate, malonic
acid, dimethyl malonate, succinic acid, dimethyl succinate, methylsuccinic
acid, glutaric acid, dimethyl glutarate, 2-methylglutaric acid, 3-methylglutaric
acid, adipic acid, dimethyl adipate, 3-methyladipic acid, 2,2,5,5-
tetramethylhexanedioic add, pimelic acid, suberic acid, azelaic acid,
dimethyl azelate, sebacic acid, 1,11-undecanedicarboxylic acid, 1,10-
decanedicarboxylic acid, undecanedioic acid, 1, 12-dodecanedicarboxylic
acid, hexadecanedioic acid, docosanedioic acid, tetracosanedioic acid,
dimer acid, 1 ,4-cyclohexanedicarboxylic acid, dimethyl-1 ,4-
cyclohexanedicarboxylate, 1 ,3-cyclohexanedicarboxylic acid, dimethyl-
1 ,3-cyclohexanedicarboxylate, 1, 1-cyclohexanediacetic acid, metal salts of
5-sulfo-dimethylisophalate, fumaric acid, maleic anhydride, maleic acid,
hexahydrophthalic acid and phthalic acid.
21. The composition as claimed in claim 17, wherein the diol is selected from the
group consisting of mono ethylene glycol, ethylene glycol, 1 ,3-propanediol,
1 ,4- butanediol, 1 ,6-hexanediol, 1 ,8-octanediol, 1,1 0-decanediol, 1,12-
dodecanediol, 1, 14-tetradecanediol, 1, 16-hexadecanediol, dimer diol, 1 ,4-
cyclohexanedimethanol, di (ethyiene glycol), tri (ethylene glycol), poly
(ethylene ether) glycols, poly (butylene ether) glycols, branched diols,
isosorbide, (cis, trans)1 ,3-cyclohexanedimethanol and (cis, trans) 1,4
cyclohexanedimethanol.
22. The composition as claimed in claim 21, wherein the said branched diol is
selected from C4-C16 aliphatic branched diols from the group consisting of
2-methyl-1 ,3-propanediol, 2,2-dimethyl-1 ,3-propanediol, 2-butyl-2-ethyl-1 ,3-
propanediol arid trimethylpentanediol.
23. The composition as claimed in claim 17, wherein said flame retardant is
selected from the group consisting of 2-Carboxyethyl(phenyl) phosphinic
acid or 3- hydroxyphenylphosphinyl-propanoic acid), 9,1 0-dihydro-1 0-[2,3-
di(hydroxylcarbonyl)propyl]1 0-phosphaphenanthrene-1 0-oxide, 2,2-
Bis(chloromethyl)trimethylene bis[bis(2-chloroethyl)] Phosphate, Chlorendic
acid, tetrakis(2-chloroethyl)dichloroisopentyldiphosphate, Tris(2-
ch loroethyl)phosphate, tris(1-chloro-2-propyl)phosphate, tris(2,3-dichloro-1-
propyl)phosphate,
hexachlorocyclopentadienyl-dibromocyclooctane,
tetrakis(2-chloroethyl)dichloroisopentyldiphosphate, tris(2-
chloroethyl)phosphate, Poly(2,6-dibromo-phenylene oxide), tetra-decabromodiphenoxy-
benzene, 1 ,2-Bis{2,4,6-tribroryio-phenoxy) ethane, 3,5,3,5-
Tetrabromo-bisphenol A (TBBA), TBBA unspecified, TBBA-epichlorhydrin
oligomer, TBBA-TBBA-diglycidyl-ether oligomer, TBBA carbonate oligomer,
TBBA carbonate oligomer, phenoxy end capped, TBBA carbonate oligomer,
2,4,6-tribromo-phenol terminated, TBBA-bisphenol A-phosgene polymer,
brominated epoxy resin end-capped with tribromophenol, TBBA-(2,3-
dibromo-propyl-ether), TBBA bis-(2-hydroxy-ethyl-ether), TBBA-bis(
allyl-ether), TBBA-dimethyl-ether, Tetrabromo-bisphenol S, TBBS-bis-(2,3-
dibromo-propyl-ether), 2,4-dibromo-phenol, 2,4,6-tribromo-phenol,
pentabromo-phenol, 2,4,6-Tribromo-phenyl-allyl-ether, tribromo-phenyl-allylether,
bis(methyl)tetrabromo-phthalate, Bis(2-ethylhexyl)tetrabromo-phtalate,
2-Hydroxy-propyl-2-(2-hydroxy-ethoxy)-ethyi-TBP, TBPA, glycol and
propylene-oxide esters, N,N-Ethylene-bis-(tetrabromo-phthalimide),
ethylene-bis(5,6-dibromo-norbornane-2,3-dicarboximide), 2,3-Dibromo-2-
butene-1 ,4-diol, Dibromo-neopentyl-glycol,
Dibromo-propanol, tribromo-neopentyl-alcohol, poly tribromo-styrene and
combination thereof.
24. The composition as claimed in claim 23, wherein preferably the flame
retardant is 2-carboxyethyl (phenyl) phosphinic acid [also known as 3-
(hydroxyphenylphosphinyl) propanoic acid] or 9,1 0-dihydro-1 0-[2,3-di
(hydroxyl carbonyl) propyl]1 0-phosphaphenanthrene-1 0-oxide or combination
thereof.
25. The composition as claimed in claim 17, wherein said one or more additives,
other than FR additives, is sodium acetate anhydrous in an amount up to 100
ppm and preferably 60 ppm.
26. The composition as claimed in claim 17, wherein one or more additives, other
than FR additives, is preferably pentaerythritol in an amount up to 1000 ppm
and preferably 700 ppm.
27. The composition as claimed in claim 17, wherein the said composition
comprises a nucleating agent in an amount up to 5000 ppm.
28. The composition as claimed in claim 27, wherein the nucleating agent is an
inorganic or organic nucleating agent in an amount ranging between 5 ppm
and 2000 ppm of total mass of the said composition.
29. The composition as claimed in claim 27, wherein the inorganic nucleating
agent is at least one selected from the group consisting of calcium silicate,
nano silica powder, talc, Microtalc, Aclyn, kaolinite, montmorillonite, synthetic
mica, calcium sulfide, boron nitride, barium sulfate, aluminum oxide,
neodymium oxide and a metal salt of phenyl phosphonate.
30. The composition as claimed in claim 27, wherein the organic nucleating agent
is at least one selected from the group consisting of carboxylic acid metal
salts such as sodium benzoate, potassium benzoate, lithium benzoate,
'
calcium benzoate, magnesium benzoate, barium benzoate, lithium
terephthalate, sodium terephthalate, potassium terephthalate, calcium
oxalate, sodium laurate, potassium laurate, sodium myristate, potassium
myristate, calcium myristate, sodium octacosanoate, calcium octacosanoate,
sodium stearate, potassium stearate, lithium stearate, calcium stearate,
magnesium stearate, barium stearate, sodium montanate, calcium montanate,
sodium toluoylate, sodium salicylate, potassium salicylate, zinc salicylate,
aluminum dibenzoate, potassium dibenzoate, lithium dibenzoate, sodium 13-
naphthalate and sodium cyclohexane carboxylate, organic sulfonates such as
sodium p-toluene sulfonate and sodium sulfoisophthalate, carboxylic acid
amides such as stearic acid amide, ethylene bislauric acid amide, palmitic
acid amide, hydroxystearic acid amide, erucic acid amide and tris(tbutylamide}
trimesate, phosphoric compound metal salts such as benzylidene
sorbitol and derivatives thereof, and sodium-2,2'-methylenebis(4,6-di-tbutylphenyl)
phosphate; and 2,2-methylbis(4,6-di-tbutylphenyl)
sodium.
31. The composition as claimed in claim 27, wherein said composition optionally
comprising miscellaneous excipients such as polycondensation catalysts or
other additives.
32. The composition as claimed in claim 17, wherein the nucleating agent is
selected from the group consisting of oligomers such as PET, PBT, PTT,
PTN, PBN or PEl.
33. The composition as claimed in claim 17, wherein the said composition can be
melt blended with normal polyester and subsequently extruded to yarns or
fibers.
34. A method for the preparation of a flame retardant polymer composition
comprising:
(a) Preparing slurry of pure terephthalic acid (PTA) and ethylene glycol
(MEG) in ratio of about 70:30 wt% along with sodium acetate
anhydrous and petaerythritol in presence of catalyst;
(b) Preparing diester along with low molecular weight esters by
esterification of slurry at inert atmosphere;
(c) Adding phosphorus based flame retardant additive and doing further
polymerization;
(d) Melt Polymerizing the said diester in presence of one or more
catalysts or combinations thereof to extrude strands of molten
polymer;
(e) Preparing amorphous chips from strands obtained in step (c);
(f) Crystallizing said amorphous chips obtained in step ·(d) at
temperature of about 12o•c to 1so•c for 2 to 6 hours to obtain
crystalline polymer;
(g) Solid state polymerization at temperature of about 19o•c to 21 o·c of
said crystallized polymer.
35.The method as Claimed in claim 34, wherein the melt polymerization can be
carried out in either batch reaction, or continuous polymerization line.
36. The method as claim__ed in claim 34, wherein the melt polymerization can be
carried out in either batch or continuous mode.
37. The method as claimed in claim 34, wherein the catalysts may be selected
from the group consisting of antimony trioxide, antimony triacetate, Ti
compounds, gennanium dioxide, tin compounds or c.ombinations thereof.