FIELD OF THE INVENTION:
The present disclosure generally relates to a heat resistant polymer
compositions and improved performance thereof. More particularly, it
relates to a process for the preparation of polyethylene terephthalate
(PET) polyester composition with improved thermal, optical, mechanical
and rheological properties which can withstand high temperature without
any deformation in its original shape.
BACKGROUND OF THE INVENTION:
For food packaging, gas/moisture barrier property is one of the key
elements to provide longer shelf life of products. Aluminum foils,
4
aluminum-metalized films, PVDC-coated films, or coextruded EVOH
films have played major roles in barrier packaging. However, there are
increasing demands for more sophisticated packaging, such as
transparency, metal detector capability, microwaveability, and
environmental friendliness as well as barrier properties. Polyester films
are capable of meeting such demands and have become very popular
recently.
PET polyester is a homopolymer made from one part dibasic acid or ester
thereof i.e., TPA or DMT), and one part diol, e.g. MEG. Whereas
copolymer is made from more than one dibasic acid or ester thereof and
dioL Copolymers have some advantages over homopolymers as the
2
copolymers remove processing limitations and provide increased
physical properties at elevated temperature. In addition to DMT or TP A,
isophthalic acid (IP A) can be used as a comonomer to reduce the rate and
degree of crystallization to an extent that depends on its dosage. This
broadens the processing parameters of food-container manufacturing
machines. Glycols offer several opportunities for modification. During
polycondensation, EG reacts with itself to some extent to form diethylene
glycol (DEG). Higher amounts of DEG affect many polymer properties.
There are other glycols available as partial substitutes for EG (e.g.,
neopentyl glycol, cyclohexane dimethanol). All these modifications lead
to desired polymer property changes, i.e., reduction of the crystallization
rate, melting point, etc... Cyclohexane dimethanol (CHDM) can react
I
with a mixture of terephthalic and isophthalic acids in order to increase
the melt strength of the polymer for extrusion processes.
On the other hand, some injection-molding and thermoforming
applications can lead to improved heat resistance by accelerated
crystallization rates in the article, which prevents physical deformation at
elevated temperatures. This objective can be achieved by nucleation,
which involves the addition of other ingredients to the polymer. Inert,
insoluble substances (e.g., mica, talc), organic substances (e.g., aromatic
alcohols), and certain polymers (e.g., PP, PE) can be used as nucleation
ingredients to increase crystallization rates without compromising in
transparency.
3
Such homopolymers are used to manufacture containers (i.e., bottles), by
injection blow molding or hljection-stretch blow molding. PET is also
used for "ovenable" trays for frozen food and prepared meals. These
trays are thermoformed from cast PET film and crystallized.
Crystallization heat-sets the article to prevent deformation during
cooking and serving. The main advantages of PET for this application
include suitability for both conventional and microwave ovens.
US 3755251 A relates to a process for the direct esterification of
terephthalic acid with an alkylene glycol which comprises esterifying
terephthalic acid with an alkylene glycol containing 2 to about 1 0 carbon
4
atoms per molecule under direct esterification~ conditions wherein the
glycol and acid are reacted in the presence of about 0.005 to about 0.100
weight percent based on the glycol, of a halogenated phenol employed as
a catalyst therefor, selected from the group consisting of 4-iodophenol,
2,4,6-triiodophenol, 2,4,6-triiodo-m-cresOl, tetrabromocatechol and
2, 4, 6-trii doresorcino 1.
US7199210 B2 relates to a process for the preparation of polyethylene
terephthalate by making use of non antimony catalysts. The Ti complex
catalyst is pre-dispersed in the polymer matrix selected from PET, PBT,
PCTG, PETG, PCT, PEN, PPT, PIT or any other related polyesters and
prepared as a master batch. The key feature of the process is that the
4
..
polyester obtained is having good whiteness, as against the yellowness
normally encountered with Ti based catalysts, and also the polyester has
very good clarity with minimum haze.
Similarly, EP 1413593 (CA 2451994) uses a product of tetra alkyl
titanium compounds along with a phosphorous based compound and an
aromatic carboxylic acid and claims a polyester having high 'L' and low
'b' values with reduced acetaldehyde.
CN 201410483490 discloses a heat-resisting polyethylene terephthalate
resin composition and a preparation method thereof. The heat-resisting
polyethylene terephthalate resin composition comprises the following · -
4
raw materials in parts by mass: 66-72 parts of polyethylene terephthalate,
15-18 parts of carbon fibers, 5-10 parts ofpolyetherketone, 1-3 parts of
di(3,5-tertiary butyl-4-hydroxyphenyl) sulfide and 4-6 parts of styreneacrylonitrile-
maleic anhydride copolymers. The resin obtained by
reasonably compounding the polyethylene terephthalate, the carbon
fibers, the polyetherketone, the di(3,5-tertiary butyl-4-hydroxyphenyl)
sulfide and the styrene-acrylonitrile-maleic anhydride copolymers not
only has relatively good comprehensive property, but also has good heat
resistance, and is capable of resisting high temperature of200 DEG C.
US3696071 A provides a process for the preparation of a linear high
molecular weight, film and fiber forming polyester, which comprise
5
reacting an aromatic dicarboxylic acid with a polyol containing 2 to
about 10 carbon atoms per molecule under direct esterification conditions
in the presence of an equimolar mixture of cuprous and cupric inorganic
chloride salts in an amount sufficient to catalyze said reaction and to
improve the thermal and aminolytic stabilization of said polyester, and
then further polycondensing said polyester until the desired viscosity is
obtained.
To become dual-ovenable, the PET must be crystallized during the
thermoforming process. The PET, e.g. Crystallized (Polyethylene
Terephthalate) (CPET), contains nucleating agents that assist in the
molecular crystallization. A key factor to consider, while the1moforming
CPET, is the intrinsic viscosity (LV.) of the material. The amount of
crystallization and the LV. determines the balance between the
container's stiffness at low and high temperatures. Generally the
crystallinity of the finished container is 28-32% and the LV. ranges from
0.85 to 0.95. The transparency, however, is affected due to high
crystallinity and the finished articleshas some haze effect leading to
lower transparency.
During the polymer manufacturing, the polymer, due to fast
crystallization nature of PET, gets some crystallization on cooling from
polymer melt under water cutter which leads to some crystallinity in the
6
polymer chips. Thus, the polymer gets crystallized while granulating
polymer chips from the molten polymer.
It is therefore desired to control the crystallinity of the polyester or of
articles manufactured thereof up to 45%. It is also desired to control
shape and size of the crystallites up to 0.5 micron in such a manner that
finished article can have improved heat resistance so that it can withstand
to microwave temperature without any deformation in its original shape.
OBJECTS OF THE INVENTION:
An object of the present invention, is to obtain heat resistant and
microwaveable polyethylene terephthalate polyester with improved
processability and molding properties and products made thereof.
Another object of the present invention, is to provide a process to
manufacture modified polyester with improved heat resistance properties
suitable for making articles which can withstand high temperature.
Another object of the present invention, is to control the growth and
propagation of crystallites of the modified polyester so as to achieve .
good transparency and clarity.
7
Further object of the present invention, is to provide a process for
preparing polyethylene terephthalate polyester with improved thermal,
optical, mechanical and rheological properties.
Further object of the present invention, is to provide a process to promote
both nucleation and propagation of crystallization of the polyethylene
terephthalate polyester simultaneously.
Still further object of the present invention, is to provide transparent rigid
packaging containers, films including other polymeric articles which are
capable of withstanding microwave temperature without undergoing any
deformation.
Still another object of the present invention, is to achieve the crystalized
polyester with improved impact strength.
Further object of the present invention, is to prepare articles made of the
modified polyester through Injection Blow Moulding (IBM), Injection
Stretch Blow Moulding (ISBM), and Extrusion Blow Moulding (EBM)
and the like methods.
Other objects and advantages of the present disclosure will be more
apparent from the following description which is not intended to limit the
scope of the present disclosure.
8
SUMMARY OF THE INVENTION
The present invention provides a novel composition of the copolyester
and improved process for manufacturing thereof The process of the
present invention becomes distinct over the prior art when it incorporates
both steps nucleation for initiating the crystallization and suppression to
control the size of the crystallites during the crystallization, in melt
polymerization phase.
The crystallization of the polyester can be achleved by additional of
nucleating agents e.g. PBT etc. whlch are responsible to increase the rate
of crystallization on the other hand the suppression of the crystallization
is achieve by adding slow crystallizing additives to the reaction mixture
during esterification. Thus, the extent of crystallinity and size and shape
of the crystallites can be controlled by the process of the present
disclosure to a level sufficient to maintain the required thermal,
mechanical and optical properties of the PET polyester. Thus, the process
of the present invention helps to achieve the crystallinity up to 4 %;
crystals of spherules size up to 0. 5 micron and I. V. up to .94 dl/g.
The crystallization rate and growth of crystallites can be controlled by
slightly retarding the rate of crystallization. The slight retardation in the
9
0 •
rate of crystallization helps limiting the shape and size of the crystallites
and ensures transparency along with increase crystallinity.
Thus, the crystallized polyester of the present disclosure is suitable for
rigid packaging or containers by application for transparent containers in
both monolayer as well as multilayer containers.
In accordance with one aspect of the present invention, there is provided
a heat resistance, preferably microwaveable, polyethylene terephthalate
(PET) polyester composition that includes but is not limited to:
a. at least one dicarboxylic acid;
b. at least one diol;
c. at least one nucleating agent;
d. at least one or more crystallization suppressing agents;
e. at least one or more additives;
wherein the composition is characterized by at least one of the
following properties:
• Intrinsic Viscosity> 0.56 dL/g;
• Glass transition temperature (Tg) < 60 °C; and
• Crystallization exothermic peak temperature (Tch) < 60 °C.
In accordance with one of other aspect of the invention, there is provided
a process for the preparation of the polyethylene terephthalate (PET)
composition comprising:
10
(a) esterification of dicarboxylic acid and diol under atmospheric
pressure and temperature between 170°C to 225°C for 3 to 4
hours;
(b) melt polymerization using DMT or MEG (DMT route process)
or PTA and MEG (PTA route process) in presence of one or
more catalysts or combinations thereof to extrude copolyester
having intrinsic viscosity about 0.50 dL/g;
(c) addition of at least one nucleating agent in the esterification or
polymerization;
(d) preparing amorphous granules from extrude obtained in step
(b);
(e) crystallization of said amorphous granules obtained in step (d)
in rotary or fluid bed crystallizer at temperature of about l20°C
to about 150°C for about 2 to about 6 hours to obtain surface
crystallization granules;
(f) Solid state polymerization of the crystallized granules at
temperature of about 150°C and below melting temperature for
about 4 to about 16 hours resulting in intrinsic viscosity (IV)
about 0.95 dl/g or higher, and oligomer contents < 105
meq/gm.
DETAILED DESCRIPTION OF INVENTION:
The present invention, provides modified polyethylene terephthalate
polyester composition that can be used to produce transparent articles
11
with improved thermal, optical, mechanical and rheological properties. In
one aspect of the present invention, the modified polyethylene
terephthalate can be processed to make transparent containers by
extrusion and thermoforming and i11jection blow moulding techniques.
The containers made from the modified polyethylene terephthalate (PET)
have sufficient crystallinity so as to resist hot filling at up to 90°C
temperature. The containers comprising the modified PET can also be
heated in microwave at temperature about l20°C without shrinkage or
shape deformation.
In accordance with one aspect of the present disclosure, there is provided
a heat resistance, preferably microwaveable, polyethylene terephthalate
I
(PET) polyester composition suitable for manufacturing heat resistant
and/or microwaveable transparent containers that includes, but not
limited to:
• at least one dicarboxylic acid;
• at least one diol;
• at least one nucleating agent for initiating crystallization;
• at least one crystallization suppressing agent for retarding the
crystallization;
• at least one or more additives.
Wherein, the polyester is characterized by at least one of the
following properties:
• Intrinsic Viscosity> 0.50 dl/g;
12
• Glass transition temperature (Tg) < 60 °C; and
• Crystallization exothermic peak temperature (Tch) < 60 °C.
Post-consumer recycled (PCR) PET flakes instead ofPTA/DMT & MEG
can be used as starting raw material. The recycling route can be
mechanical extrusion or glycolysis with required filtration scheme.
Typically, the dicarboxylic acid is aliphatic and/ or aromatic acid and is
at least one selected from the group that includes but is not limited to
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),
l
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
acid, 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-! ,4-cyclohexanedicarboxylate,
1 ,3-cyclohexanedicarboxylic acid, dimethyl-1,3-
cyclohexanedicarboxylate, 1,1-cyclohexanediacetic acid, metal salts of5-
sulfo-dimethylisophalate, fumaric acid, maleic anhydride, ·maleic acid,
hexahydrophthalic acid and phthalic acid. In one embodiment, 90-98
mol% of dicarboxylic acid is present.
The dicarboxylic acid of this embodiment preferably 1s purified
terephthalic acid (PTA) or dimethyl terephthalate (DMT).
In another embodiment, 2-10 mol% of dicarboxylic acid is present. The
dicarboxylic acid of some embodiment is selected from the group
consisting of isophthalic acid (IP A), 2, 6-napthalene dicarboxylic acid
(NDA), adipic acid, sebacic acid succinic acid, azelic acid and/or
combination thereof.
Typically, the dial is at least one selected from the group that includes
but is not limited to mono ethylene glycol (MEp), diethylene glycol ,
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 dial, 1 ,4-cyclohexanedimethanol, di( ethylene
glycol), tri( ethylene glycol), poly( ethylene ether) glycols, poly(butylene
ether) glycols, branched dials, isosorbide, (cis, trans) 1,3-
cyclohexanedimethanol and (cis, trans) 1,4 cyclohexanedimethanol.
Typically, the branched dial includes C4-C16 aliphatic branched dials
and is at least one selected from the group that includes but is not limited
to 2-methyl-1, 3-propanediol, 2, 2-dimethyl-1, 3-propanediol, 2-butyl-2-
ethyl-1, 3-propanediol and trimethylpentanediol. In the embodiment
where a cycloaliphatic dial moiety is included as a dial, it is
supplemented with at least one additional cyclic or branched dial. In one
14
embodiment 80-99 mol% of mono ethylene glycol (MEG) is used as the
diol.
The liquid plasticizer of the present disclosure includes, but 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-methyl-N-butyl benzene sulfonamide, Nmethyl-
N-ethyl benzene sulfonamide, N-methyl-N-propyl benzene
sulfonamide, N-ethyl-N-propyl benzene sulfonamide, N-ethyl pethylbenzene
sulfonamide, N-ethyl p(t-butyl)benzene sulfonamide, Nbutyl
p-butyl benzene sulfonamide, N-butyl (mixed) toluene
sulfonamide, N-t-octyl (mixed) toluene sulfonamide, N-ethyl-N-2-
ethylhexyl (mixed) toluene sulfonamide and N-ethyl-N-t-octyl1 (mixed)
l
toluene sulfonamide and tri octyl trimellitate. The aforementioned term
'mixed' may be defmed as a mixture of the ortho and para isomers of
toluene.
A nucleating agent is included in the composition of the present
disclosure to improve its crystallinity and heat deformation temperature.
The nucleating agent is inorganic and/ or organic nucleating agent and is
present in an amount ranging between 5 ppm and 2000 ppm with respect
to the total mass of the composition. The inorganic nucleating agent is at
least one selected from the group that includes but is not limited to
. calcium silicate, nano silica powder, talc, Microtalc, Aclyn, kaolinite,
montmorillonite, synthetic mica, calcium sulfide, boron nitride, barium
15
sulfate, aluminum oxide, neodymium oxide and a metal salt of phenyl
phosphate.
In some embodiments of the present invention, the inorganic nucleating
agent is modified by an organic material to improve its dispersibility in
the composition of the present invention.
The organic nucleating agent of the present invention is at least one
selected from the group that includes but is 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 p-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(t-butylamide)
trimesate; phosphoric compound metal salts such as benzylidene sorbitol
and derivatives thereof, and sodium-2,2'-methylenebis(4,6-di-t-
16
butylphenyl)phosphate; and 2,2-methylbis( 4,6-di-t-butylphenyl)sodium
and polymers.
In one aspect of the present invention, the nucleating agent is a polymeric
material. The polymeric material used in the present method is selected
from the group that includes, but not limited to, end-capped oligomers,
low I.V. Polymers of PET, PBT, PTT, PTN, PBN etc. In some
embodiments of the present invention the polymeric materials can be
added in chips form. In some of the embodiments the nucleating agent
can be manufactured in-situ nucleating agents. In some embodiments
portion of fast crystallizing agent, e.g. polybutylene terephthalate (PBT)
can be replaced by alternative polymers, e.g. polyolefin. Thus the use of
PBT can be reduced up to 5 wt. %. The polyolefin are used in an amount
about 2 wt. % to 5 wt. %.
A suppressing agent is added during the process of the present invention,
to retard the crystallization so that the growth and propagation of
crystallites can be controlled as per requirement. The suppressing agent is
selected from the group that includes but is not limited to dicarboxylic
acids, dial, and slow crystallized polymers, e.g. polyesters, polyolefin,
etc. In one embodiment the suppressing agents are used in an amount up
to20 wt. %.
In accordance to one embodiment, the dicarboxylic acids used as
suppressing agents are selected from the group that includes but is not
17
limited to isophthalic acid (IPA), 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 acid, 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. In one
embodiment the diacid used as suppressing agent preferably is
isophthalic acid (IPA).
In one of the embodiments, the diol used as suppressing agent is at least
one selected from the group that includes but is not limited to mono
ethylene glycol (MEG), diethylene 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,
18
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. Typically, the branched diol includes C4-
C16 aliphatic branched diols and is at least one selected from the group
that includes but is not limited to 2-methyl-1, 3-propanediol, 2, 2-
dimethyl-1, 3-propanediol, 2-butyl-2-ethyl-1, 3-propanediol and
trimethylpentanediol. In the embodiment where a cycloaliphatic diol
moiety is included as a diol, it is supplemented with at least one
additional cyclic or branched diol. In one embodiment the diol used as
suppressing agent preferably is diethylene glycol (DEG) or propylene
glycol (PEG).
The composition may also have other additives such as polycondenzation
catalysts and other additives. Catalysts that may be used include salts of
Li, Ca, Mg, Mn, Zn, Pb, Sb, Sn, Ge, and Ti, such as acetate salts and
oxides, including glycol adducts, and Ti alkoxides. These are generally
known in the art, and the specific catalyst or combination or sequence of
catalysts used may be readily selected by a skilled practitioner. The
preferred catalyst and preferred conditions differ depending on, for
example, whether the diacid monomer is polymerized as the free diacid
or as a dimethyl ester and the exact chemical identity of the other diol
component.
19
' I
The other additives include but are not limited to pigments; flame
retardant additives, particularly, decabromodiphenyl ether and
triarylphosphates, such as triphenylphosphate; reinforcing agents, such as
glass fibers; thermal stabilizers; ultraviolet light stabilizers processing
aids, impact modifiers, flow enhancing additives. Other possible
additives include polymeric additives including ionomers, liquid crystal
polymers, fluoropolymers, olefms including cyclic olefms, polyamides,
ethylene vinyl acetate copolymers and the like.With the help of melt
phase polymerization polymer granules of I. V. of 0. 73 dl/g to 0.95 dl!g
can be manufactured on cooling the molten polymer under water and
further cut it into chips .Thus, the amorphous polymer chips obtained
from the above process are further upgraded in solid state polymerization
(SSP) to achieve the required LV. level. The co polymer produced in this
manner have improved heat resistance, good color (L* > 60%, a* of -2.2
& b* of >2.5) and good transparency, improved melt flow characteristic
and can be used to manufacture articles by normal ISBM, IBM, IM,
EBM processes (without heat set blow molding process) for applications
in rigid packaging containers and films. The articles of the modified
polyester can be manufactured by any process known in the art.
In case of 4/5 gallon water containers, the containers can be washed at
elevated temperature above 60°C. (72 to 85 degree Celsius or even
higher temperature if required).
In accordance with another aspect, there is provided a process for the
preparation of modified polyethylene terephthalate composition. The
20
process involves melt polymerization and subsequent solid state
polymerization process. The melt polymerization process can be carried
out either using DMT or MEG (DMT route process) or PTA and MEG
(PTA route process) or using PCR PET flakes by employing glycolysis
and repolymerization process to yield amorphous granules of I.V. range
0.73 dl/g to 0.95 dllg. During the process catalyst and additives are
incorporated at appropriate stages. Catalyst like antimony trioxide,
antimony triacetate, Ti compounds, germanium dioxide, tin compounds,
cobalt acetate etc. can be used as catalysts. Phosphorous compounds such
as phosphoric acid may be used as stabilizers. Food grade di stuffs/tonors
or cobalt acetate are used as a color moderators.
1 The amorphous polymer granules manufactured by melt phase
polymerization are crystallized in any convention crystallizer and
subsequently processed in batch or continuous solid state polymerization
(SSP) to get the desired intrinsic viscosity (I.V.). The batch SSP may be
pursed with nitrogen to expedite the reaction. In continuous SSP the
circulating nitrogen gas is used as a carrier ofbyproducts.
The melt polymerization process is a process for making the polymer and
is described in detail below. The melt polymerization processes may be
based on DMT route or PTA route or PCR PET flakes based route.
The present disclosure can also be carried out by using batch process or
continuous process in both melt polymerization and solid state
polymerization.
21
Melt Polymerization:
The melt polymerization process can be carried out in either batch, semicontinuous
or continuous mode. The process 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 diethylene glycol (DEG). Melt polycondensation can be
carried out in conventional processes like PTA, DMT and PCR PET
glycolysis. When terephthalic acid is used in the polymerization process,
the volatile r~action product will be water; when an ester such as
l
dimethyl terephthalate is used, the volatile reaction product will be the
corresponding alkanol (such as methanol), together with smaller amounts
of water.
Solid state polymerization:
The copolyester can be made by the melt condensation process described
above having an inherent viscosity of at least about 0.750 dllg, and often
as high as about 0.95 dl/g or greater, without further treatment. For
microwaveable Co-PET articles, a copolyester having an inherent
viscosity of at least about 0.750 dllg, and preferably about 0.95 dllg, is
generally desirable to obtain articles having good thermal and optical
properties. The product made by melt polymerization, after extruding,
22
cooling, and pelletizing, is in amorphous state (crystallinity\~:-._.<-<:,_:_-.:.:·_. ·_._:- _.. .- :-·:: ·__ ,·. __ :;_:.,. <_,·,-_._-::>;~:,,;_.:·.-:~\~:,:::·._:_;·_: .. ;_ ... _,-. -
inorganic; ()rganic; or a polymeric material. .
In accordance 'Xith,yetanoth.eraspect, ~he at least one nucleating agent is
present.in an a~ount ranging bl(tW'e~n 5 ppm and 2000 ppm with respect
to the tqfuLmass ofthe compo!!ition.
In accotdatice with biJ,e al1other aspect, the iiiorganic nucleating agent is
at least one selept~d·from the group qonsisting of calcium silicate, nano
silica powder,jtalc,· • Microtalc, ,Aclyn, kaolinite, montmorillonite, -,._ ' -· . - ' -
synthetic mica,· qalcium sulfide, borim nitride, barium sulfate, aluminum
oxide, ne<;>gymium oxide and a )11etal ~altofphenyl phosphonate.
-_- - ---~'::·:_i:LSif~;?~~:-:·{_i:{:_--_:_r_:_:·,- _--·_ -. _.:: -: :_-__ , :-_.-: --~-:~- ;_y~--:_·- _... ,>·:~.; -- -~~·:.Y::·:- --_ - -
l.n ~c<:c)t<.l.~<:~ w~th 11po't#er aspect,the !)rganic h~cleating agent is at least .
One selected froW .. the group consistil}g of carboxylic acid metal salts such
as sodium beuioate, potassium he~oate, lithium benzoate, calcium
benzoate, magne~ium benzoate, bar~urri benzo ate, lithium terephthalate,
sodium terephth~la~e, p()tassiurnterephthalate; calcium oxalate, sodium
laurate, . potassium ' laurate, ·.. ~~diu.m. , ·.. myrlstate, potassium myristate, '- '- .
calcium myrisfate, sodium· oCtacosimoate, calcium octacosanoate, sodium
stearate, potassium. stearate, • ·lithi~m stearate, calcium stearate,
magnesium stearate, barium stearate, .:sodium montanate, calcium
montanate, sodium: tolljo)'late, ~()(li~m sillicylat~, potassium salicylate,
·,;
24.
zinc salicylate, aluminum dibenzoate, potassium dibenzoate, lithium
dibenzoate, sodium p"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(t"butylamide) trimesate, phosphoric
compound metal salts such as benzylidene sorbitol and derivatives
thereof, and sodium"2,2'"methylenebis( 4,6"di"t"butylphenyl) phosphate;
and 2,2"methylbis(4,6"di"t"butylphenyl) sodium and polymers.
In accordance with yet another aspect, the polymeric material is selected
from the group of PET, PBT, PIT, PTN, PBN, end"cap oligomers, etc.
In accordance with one another aspect, the polymeric material used in
chips .form or can be manufactured in-situ during the esterification or
polymerization reaction.
In accordance ·with another aspect, the polymeric material is in an
amount up to 70 wt% based on the weight of the polyester composition.
In accordance with yet another aspect, the polymer granules are
processed into containers by extrusion and thermoforming, or injection
stretch blow moulding (ISBM) process to achieve sufficient crystallinity.
In . orie another aspect, the containers are transparent and can withstand
high temperatUre during hot filling up to 95°C, and during heating in
microwave up to l20°C.
The products manufactured from the crystallizable and microwaveable
PET polyester of the present disclosure by normal ISBMIIBMIIM /EBM
processes has improved heat resistance and can withstand elevated
temperature above 60 °C without any deformation and with minimum
shrinkage. The other advantages of the PET composition of the present
25
i '
disclosure are good proces.sability at lower temperature, transparency and
microwaveable, HoW'ever, the articles manufactured by all above-stated
processes have good impact strength. This is significant considering the
fact that normally PET articles prepared by conventional processes and
designs cannot withstand microwave temperature. The articles prepared
by the method of the ·present disclosure are able to sustain during
microwave heating without any deformation due to high concentration of
spherical crystallites with size of less than 0.5 micro without affecting the
transparency of the article. As small size and spherical shape of the
crystallites leads to minimum reflection of the light thus articles remain
transparent with good clarity.
The present disclosure provides a modified crystallizable polyester or
!
copolyester for the manufacture of packaging articles by
ISBM(IBMIEBM processes which has heat resistant properties including
good .mechanical and optical properties. The present disclosure provides
a co polyester which has good color (L * > 75 a* of -2.2 & b* of 5.5±2.5)
and good clarity .. The present disclosure provides a polyester which has
good in1,pact strength, transparency and glass transition temperature (T g)
< 60 °C. The present disclosure provides a polyester which has improved
rheological properties which further enables manufacture of transparent
articles by ISBMIIBMIIM and EBM processes without need of heat set
blow molding and these containers have improved heat resistance and
they can be heated at elevated temperature more than 60 °C & these
articles when heated in microwave oven do not display any abnormal
26
..
shrinkage/deformation. When the articles are manufactured by heat set
blow molding using by the method known in the art, the resultant
modifi~d copolyester demonstrates further improved heat resistance and
can be heated at microwave temperature about 120 °C. The present
disclosure provides a process for the preparation of a polyester (also can
be referred to as "copolyester") composition which gives consistent
properties. The manufacturing process can be based on DMT route, PTA
route or by using PCR PET flakes in batch polymerization plant also in a
continuous polymerization plant. The up gradation can be done either in
a batch SSP plant or continuous SSP plant to achieve the required I.V.
level. The present disclosure provides a copolyester for manufacturing
transparent packaging containers well known molding process.
j
!
The present disclosure provides a copolyester resin composition suitable
for making rigid package containers by injection molding and these
containers will have good transparency, good color, good impact strength
and improved heat resistance so that they can withstand high temperature
above 60°C. The present disclosure provides a copolyester composition
with improved melt flow properties and also improved flowability to
enable manufacture of microwavable containers by injection molding
process. The present disclosure provides a copolyester resin composition
with enhanced thennal properties and optical properties.
The present disclosure is further described in light of the following
examples which are set forth for illustration purpose only and not to be
construed for limiting the scope of the disclosure.
27
Quality Parameters
Intrinsic Viscosity
Intrinsic viscosity (LV.) 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 ands-tetrachloroethane with 0.5 %concentration. The flow time
of solvent and solution are checked under LV. water bath maintained at
temperature bout 25 °C. The LV., l], was obtained from the measurement
of relative viscosity, 1Jr, for a single polymer concentration by using the
Billmeyer equation: ·
IV= [lJ] = 0.25[(RV-1) + 3 1n RV] I c
4
Wherein 11 is the intrinsic viscosity,lRV is the relative viscosity; and cis
the cpncentration of the polymeric solution (in g/dL). The relative
viscosity (RV) is obtained from the ratio between the flow times of the
solution (t) and the flow time of the pure solvent mixture (to).
RV =nrc!= Flow time of solution (t) I Flow time of solvant (to)
LV. must be controlled so that process 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. D65 illuminant and 10° angle is being used for color
measurement. Both Amorphous and Solid State Polymerized (SSP) were
2~
'·
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 light.
• 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
l
indicates yellow and a negative number indicates blue.
The L * values after SSP are higher because of whitening caused by
spherulitic crystalization of the polymer.
DEG/EG/IP AIBDO content:
To determine the Diethylene Glycol (DEG), Ethylene Glycol (EG),
Isophthalic Acid (IPA) and Butanediol (BDO) in sulfonated copolyesters,
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
29
liquid is filter through Whatman 42 filter paper. After filtration, 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 IP A/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 fmal end point is at the color
4
change from blue from yellow. COOH groups are calculated based on the
below calculation and the results are expressed in meq of COOH!kg. 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 for sample solution.
[(TR- Blank) x N x 1000] = 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 (Tg), crystallization
exothermic peak temperatures (Tch), peak endotherm temperatures (Tm),
30
heats of crystallization (11H) 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 °C 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 ((11H) 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 oligomer content in the polymer samples was determined by Soxhlet
reflux methods. Polymer samples were reflux with 1, 4-dioxane for 2
hours in aJl}!mtle heater .. After2 hours, the refluxed sample is filtered
through Wh!\!mann 42 filter paper and the filtrate was transferred to a
clean, dry, pre-weighed 100 ml glass beaker. The filtrate was th(m heated
to dryness on a hot plate at 180°C. After drying, the beaker was kept in
an air oven at 140°C for 30 minutes. Finally, the oligomer content wt.
%) was calculated according to the following:
31
•... i
'·•,
{[(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 defmed 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 defmed by the scope of the claims will occur
to those skilled in the art.
In one example, to a 20 L liter volume reactor equipped with a
mechanical stirrer, a packed reflexing column, a nitrogen inlet and a heat
source were added 2.6 kg of 1, 4 butane diol (BDO), 10.5 kg of
32
polybutylene terephthalate (PBT) chips, 4.5 kg of isophthalic acid (IP A),
1.9 g of cobalt acetate (30 ppm as cobalt), 3 gm of nyacol dp5480 (200
ppm), 0.150 gm of micro talc. The esterification was carried out at
temperature of 220-225 °C under pressure up to atmospheric pressure for
3-4 hours. The reaction byproduct, i.e., butanol was collected before
addition of IP A. After completion of the esterification, the monomers,
oligomers, were transferred into polycondenzation reactor.
Polycondenzation reaction was carried out at temperature of 225 - 260
°C under pressure of 760 torr. After completion of the polymerization
and sufficient melt viscosity is achieved, polymerization was stopped.
The molten copolymer was cooled in the cold water and then chopped to
form pellets. The intrinsic viscosity of the amorphous copolymer is
0.0.72 dl/g. The amorphous chips obtained from the above said process
were further subjected to solid state polymerization to increase the LV.
up to 0.95 dl/g. The reaction conditions particularly, temperature,
pressure and time mentioned in the above example are varying and may
be decided the process conditions of the esterification and polymerization -· reaction.
In one example, initially 13.75kg ofBDO were charged in a esterification
reactor under atmospheric pressure and at temperature ranging from
170°C to 220 °C, then 56 kg of polybutylene terephthalate (PBT) chips
and 30 PPM of cobalt acetate (CoAc) were added to the BDO solution,
then the mixture were reacted under atmospheric pressure at temperature
ranging from 170°C to 225 °C with peak temperature 224 °C. The molar
33
ratio of the PBT and BDO is 1:0.60. Esterification reaction were
conducted for next 2 to 3 hours and the reaction byproduct, i.e.,
butanediol (BDO), were removed before addition ofiPA. After removing
the IP A, 24.0 kg of polyethylene terephthalate (PET) chips, 200 PPM of
micro talc and 0.150 gm of nyacol dp5480 were added to the
esterification reactor and were reacted under atmospheric pressure and
temperature about 225 °C to complete the esterification reaction. After
the esterification reaction is complete, the monomer were transferred via
a 20 micron filter into the polycondensation reactor. Thereafter, the
polymerization reaction were conducted under vacuum and temperature
ranging from 225 °C to 255 °C with a peak for245°C for two hours. The
molten polymer, after achieving the required LV. up to 0.72 dVg was
extruded and cut into chips under water cutter to obtain amorphous chips
of the polyester. The amorphous chips obtained from the above said
process were further subjected to solid state polymerization to increase
the LV. up to 0.94 dVg. The reaction conditions particularly, temperature,
pressure and time mentioned in the above example are varying and may
be decided by the person skilled in the art based on his knowledge of on
the process conditions of esterification and polymerization.
In one working example, up to about 24 wt% of polyethylene
terephthalate, up to 10 wt% of isophthalic acid (IP A), and up to 70 wt%
of polybutylene terephthalate or polybutylene naphthalate were reacted in
the reactor as per the methods disclosed in the present invention to obtain
the crystallized heat resistant polyester. Wherein the wt% is calculated
34
I,
based on the total weight of the fmal polyester. The heat resistant
polyester was further processed to obtain transparent containers through
extrusion and thermoforming techniques.
In an example containers can be manufactured through injection stretch
blow moulding (ISMB) process, the modified heat resistant polyethylene
terephthalate obtained from the above methods is used to manufacture 38
g*130 mm long on 4 caring injection molding machine of 130 tonnage.
Prior to that the resin was dried at 170°C for 5 hours. The molding
temperature was 280-285°C. The preforms were conditioned for 24 hours
before starting blowing into bottles on blowing machine with single
caring. The pre-forms were heated to ll2°C. The blowing cycles time
was 4.13 sec. Preblow pressure was 8 bar. Blow pressure was 30 bar. The
bottles thus produced could be filled at 82±2°C without any deformation.
i
In one another working example, the polyester obtained from the above
examples was used on injection moulding machine to manufacture
containers. Prior to that the chips were dried at 160°C for 7 hours. The
mold was cooled with chilled water of 6°C. The melt flow was
satisfactory. The containers of 350Jl wall thickness were manufactured.
The containers were of good color & transparency and could be filled at
82°C temperature.
35
In a preferred example the polyester chips obtained from the methods of
the present invention are first converted into polyester sheets by
extrusion process, then the sheet was heated to a pliable temperature
using electric heaters. Once the sheets are heated, the soften sheet is
placed on the mold and the desired shape is obtained by applying an
external pressure. Finally finishing processes such as trimming, drilling,
etc. are carried out when the shape is cooled and hardened. The fmished
container obtained can be used for various applications such as food
packaging.
The embodiments herein and the various features and advantageous
d~tails 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.
The foregoing description of the specific embodiments will so fully
reveal 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
36
genenc concept, and, therefore, such adaptations and modifications
should and are intended to be comprehended within the meaning and
range of equivalents ofthe 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" suggests the use of
one or more elements or ingredients or quantities, as the use may be in
the embodiment gf the disclosure to achieve one or more of the desired
l
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. It 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
37
.. .· i
disclosure. 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 polyethylene terephthalate (PET) composition suitable for manufacturing heat
resistant and/or microwaveable containers comprising:
a. at least one dicarboxylic acid;
b. at least one diol;
c. at least one nucleating agent;
d. at least one or more crystallization suppressing agents;
e. at least one or more additives;
wherein the composition is characterized by at least one of the following
properties:
• Intrinsic Viscosity> 0.56 dL/g;
• Glass transition temperature (Tg) < 60 ot; and
• Crystallization exothermic peak temperature (Tch) < 60 °C.
2. The composition as claimed in claim 1, wherein the at least one dicarboxylic acid is
aliphatic and/or aromatic acid.
3. The composition as claimed in claim 1, wherein the at least one dicarboxylic acid is 1
selected from the group consisting of terephthalic acid, dimethyl terephthalate, l
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 acid,
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!
,4-cyclohexanedicarboxylate, 1 ,3-cyclohexanedicarboxylic acid, dimethyl-! ,3-
cyclohexanedicarboxylate, 1, 1-cyclohexanediacetic acid, metal salts of 5-sulfodimethylisophalate,
fumaric acid, maleic anhydride, maleic acid,
hexahydrophthalic acid and phthalic acid.
4. The composition as claimed in claim 1, wherein the at least one diol is selected from
the group consisting of mono ethylene glycol, diethylene 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 (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 composition as claimed in claim 4, wherein the branched diol includes C4-C16
aliphatic branched diols.
6. The composition as claimed in claim 5, wherein the branched diol is at least one
selected from the group consisting of 2-methyl-1,3-propanediol, 2,2-dimethyl-1,3-
propanediol, 2-butyl-2-ethyl-1,3-propanediol and trimethylpentanediol.
7. The composition as claimed in claim 1, wherein the at least one diol is a
cycloaliphatic diol moiety.
8. The composition as claimed in claim 7, wherein the cycloaliphatic diol moiety is
supplemented with at least one additional cyclic or branched diol.
9. The composition as claimed in claim 1, wherein the at least one nucleating agent is an
inorganic or organic nucleating agent.
10. The composition as claimed in claim 1, wherein the at least one nucleating agent is a
polymeric material.
11. The composition as claimed in claim 1, 9 and 10, wherein the at least one nucleating
agent is present in an amount ranging between 5 ppm and 2000 ppm with respect to
the total mass of the composition.
12. The composition as claimed in claim 9, 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.
13. The composition as claimed in claim 9, 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 benzo ate, 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 P-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(t-butylamide) trimesate, phosphoric compound metal salts
such as benzylidene sorbitol and derivatives thereof, and sodium-2,2'methylenebis(
4,6-di-t-butylphenyl) phosphate; and 2,2-methylbis( 4,6-di-tbutylphenyl)
sodium and polymers.
14. The composition as claimed in claim 10, wherein the polymeric material is selected
from the group of PET, PBT, PIT, PIN, PBN, end-cap oligomers, etc.
15. The composition as claimed in claim 14, wherein the polymeric material used in chips
form or can be manufactured in-situ during the esterification or polymerization
reaction.
16. The composition as claimed in claim 10, wherein the polymeric material is in an
amount up to 70 wt% based on the weight of the polyester composition.
17. The composition as claimed in claim 1, wherein the crystallization suppressing agent
is selected from the group consisting of dicarboxylic acids, diol, polyesters and
polyolefm.
18. The composition as claimed in claim 1, wherein the crystallization suppressing agent
is selected from the group consisting of isophthalaic acid, 2,6-napthalene
dicarboxylic acid (NDA), dimethyl-2,6-naphthalate (NDC), or mono ethylene glycol.
19. The composition as claimed in claim 1 and 17, wherein the suppressing agent is in an
amount up to 20 wt. %.
20. The composition as claimed in claim 17, wherein the dicarboxylic acid is selected
from the group consisting of isophthalic acid (IP A), 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 acid, 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-! ,4-cyclohexanedicarboxylate, 1,3-
cyclohexanedicarboxylic acid, dimethyl-! ,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 1 and 18, wherein the suppressing agent is
isopthalic acid (IPA).
22. The composition as claimed in claim 1 and 17, wherein the diol is selected from the
group consisting of mono ethylene glycol (MEG), ethylene glycol (EG), 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.
23. The composition as claimed in claim 22, wherein the branched diol includes C4-C16
aliphatic branched diols and is at least one selected from the group consisting of
2-methyl-1 ,3-propanediol, 2,2-dimethyl-1 ,3-propanediol, 2-butyl-2-ethyl-1 ,3-
propanediol and trimethylpentanediol.
24. The composition as claimed in claim 1 and 17, wherein the diol is diethylene glycol
(DEG) or propylene glycol (PEG).
25. The composition as claimed in claim 1, wherein the at least one or more additives is
selected from the group consisting of polycondensation catalyst, flame retardant
additives, reinforcing agents, thermal stabilizers, ultraviolet light stabilizers,
processing aids, impact modifiers, flow enhancing additives, polymeric additives
liquid crystal polymers, fluoropolymers and olefms.
26. The composition as claimed in claim 25, wherein the catalysts include salts of Li,
Ca, Mg, Mn, Zn, Ph, Sb, Co, Sn, Ge, P and Ti including glycol adducts and Ti
alkoxides.
27. The composition as claimed in claim 25, wherein the flame retardant additive is
decabromodiphenyl ether and triarylphosphates.
28. The composition as claimed in claim 25, wherein the reinforcing agents, is glass
fibers.
29. The composition as claimed in claim 25, wherein the olefins is cyclic olefins,
polyamides, ethylene vinyl acetate copolymers.
30. The composition as claimed in claim 25, wherein the catalyst is selected from the
group consisting of antimony trioxide, Cobalt Acetate, Germanium Oxide, Phosphoric
Acid, Titanium Oxide or combination thereof.
·'·
31. A process for the preparation of a heat resistant polyethylene terephthalate (PET)
composition comprising:
(a) esterification of dicarboxylic acid and diol under atmospheric pressure and
temperature between 170°C to 225°C for 3 to 4 hours;
(b) melt polymerization using DMT or MEG (DMT route process) or PTA and MEG
(PTA route process) in presence of one or more catalysts or combinations thereof
to extrude copolyester having intrinsic viscosity about 0.50 dL/g;
(c) addition of at least one nucleating agent in the esterification or polymerization;
(d) preparing amorphous granules from extrude obtained in step (b);
(e) crystallization of said amorphous granules obtained in step (d) in rotary or fluid
bed crystallizer at temperature of about 120°C to about 150°C for about 2 to
about 6 hours to obtain surface crystallization granules;
(f) Solid state polymerization of the crystallized granules at temperature of about
150°C and below melting temperature for about 4 to about 16 hours resulting in
intrinsic viscosity (IV) about 0.95 dl/g or higher, and oligomer contents < 105
meq/gm.
32. The process as claimed in claim 31, wherein the at least one nucleating agent is an
inorganic, organic, or a polymeric material.
33. The process as claimed in claim 31 and 32, wherein the at least one nucleating agent
is present in an amount ranging between 5 ppm and 2000 ppm with respect to the total
mass of the composition.
34. The process as claimed in claim 32, 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.
35. The process as claimed in claim 32, 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 benzo ate, lithium terephthalate, sodium terephthalate, potassium
terephthalate, calciuin 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
~:..._._·_•c·o..~· ----------- •
_.-.·-:~:_______: '·
toluoylate, sodilJID salicylate, potassilJID salicylate, zinc salicylate, aluminum
dibenzoate, potassium dibenzoate, lithium dibenzoate, sodium P-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(t-butylamide) trimesate, phosphoric compound metal salts
such as benzylidene sorbitol and derivatives thereof, and sodium-2,2'methylenebis(
4,6-di-t-butylphenyl) phosphate; and 2,2-methylbis( 4,6-di-tbutylphenyl)
sodium and polymers.
.. -_r __
36. The process as claimed in claim 32, wherein the polymeric material is selected fr~!ll .•
the group of PET, PBT, PIT, P'IN, PBN, end-cap oligomers, etc.
37. The process as claimed in claim 36, wherein the polymeric material used in chips
form or can be manufactured in-situ during the esterification or polymerization
reaction.
38. The process as claimed in claim 36, wherein the polymeric material is in an amount
up to 70 wt% based on the weight of the polyester composition.
39. The process as claimed in claim 31, wherein the polymer granules are processed into
containers by extrusipn and thermoforming, or injection stretch blow moulding
(ISBM) process to achieve sufficient crystallinity.
40. The process as claimed in claim 39, wherein the containers are transparent and can
withstand high temperature· during hot filling up to 95°C, and during heating in
microwave up to l20°C.