Composition comprising a semi-aromatic polyamide and a crosslinked
polyolefin
The present invention relates to a composition comprising at least one
5 semiaromatic polyamide and at least one crosslinked polyolefin, to a process for
preparing it, and to its uses, especially in the manufacture of various objects, such
as current consumer goods as for instance electrical, electronic, or automotive
equipment, surgical apparatus, packaging, or else sports articles.
10 [The prior art and the technical problem]
In the automotive industry, for example, compositions based on one or
more semiaromatic polyamides are seeing increasing use, owing to the noteworthy
thermomechanical properties that such compositions confer on components
produced from them.
15 In order to enhance simultaneously the preparation of these compositions
and their conversion, especially through the use of an extrusion, coextrusion, or
extrusion blow molding step, document WO 20111015790 describes compositions
comprising from 45% to 95% by weight of a semi-aromatic polyamide and from 5%
to 55% by weight of at least one crosslinked polyolefin, the proportions by weight
20 being given relative to the total weight of the composition.
The crosslinked polyolefin, which takes the form of a phase dispersed in
the matrix formed by the semi-aromatic polyamide, originates from the reaction:
- of a product (A) comprising an unsaturated epoxide,
- of a product (B) comprising an unsaturated carboxylic anhydride or a
25 polycarboxylic acid, and optionally
- of a product (C) comprising an unsaturated carboxylic acid or an
alpha,omega-aminocarboxylic acid.
Although such compositions can effectively be converted by extrusion,
coextrusion or extrusion blow molding, it is found that the inner and outer surfaces
30 of the tubes extruded from these compositions do not always have a homogeneous
appearance, and may carry surface defects which gives them a matt or even rough
appearance, rather than a smooth appearance. An irregular appearance to these
outer surfaces of the extruded tubes may thus have detrimental consequences for
the mechanical properties of these tubes.
It is also possible to observe the formation of deposits on the screw andlor
on the extrusion die, these deposits also being referred to as "die drooi" during this
conversion step. The formation of this die drool is not without effect on the
production of the tubes and on the maintenance of the extrusion equipment.
5 There is therefore a genuine need to find new compositions formed from a
dispersed, crosslinked polyolefin phase in a matrix of semi-aromatic polyamide(s)
that allows not only conversion without formation of die drool, but also ensures that
the extruded components obtained have smooth outer surfaces, with such
components obviously retaining all of the advantages - in terms of mechanical
10 strength, ageing resistance, and high-temperature stability - of the components
formed from the prior-art compositions based on semi-aromatic polyamide(s).
[Brief description of the invention]
Surprisingly, the applicant has found that this need is achieved with a
15 composition of the aforementioned type, namely a composition comprising at least
one semiaromatic polyamide and at least one crosslinked polyolefin, the crosslinked
polyolefin being obtained from at least one product (A) comprising an unsaturated
epoxide and from at least one product (B) comprising an unsaturated carboxylic
anhydride.
20 According to the invention, the composition has weight amounts of (A) and
(B), written respectively as [A] and [B], such that the ratio [B]I[A] is between 3 and
14.
By virtue of this specific selection of the weight amounts of (A) and (B), the
composition according to the invention can be converted by extrusion, coextrusion,
25 or extrusion blow molding, and produces components, the outersurfaces of which ~ .
are smooth, and does so without formation of die drool.
The experimental results show that improving the surface condition of
extruded components, such as tubes, is linked directly to improving the morphology
of the composition of the invention, relative to that of the composition described in
30 document WO 2011/015790. Indeed, a study of the composition of the invention by
scanning electron microscopy (SEM) shows that the composition of the invention
exhibits a nodular morphology which is particularly fine and regular, with the nodules
of crosslinked polyolefin being dispersed homogeneously within the semi-aromatic
polyamide matrix.
This enhanced morphology endows the composition of the invention with a
viscosity which is ideally suited to conversion by extrusion, especially since this
viscosity exhibits only moderate change under heat. Accordingly, it is possible to
produce components whose sizing, particularly thickness, is also optimized.
5 The invention also relates to a process for preparing the composition, and
to its uses, particularly as a constituent layer of a structure which may be singlelayer
or multilayer.
[Detailed description of the invention]
Further features, aspects, objectives, and advantages of the present
10 invention will emerge more clearly from a reading of the description and examples
which follow.
The nomenclature used in defining the polyamides is described in standard
IS0 1874-1 : 1992 "Plastics - Polyamide (PA) molding and extrusion materials -
Part 1: Designation", particularly on page 3 (tables 1 and 2), and is well known to
15 the skilled person.
It should also be noted that the expressions "between ... and ..." and "From
... to ..." that are used in the present description should be understood as including
each of the stated endpoints.
The semiaromatic uolvamide .-
20 The composition of the invention comprises at least one semiaromatic
polyamide.
This semiaromatic polyamide comprises at least one first repeating
.~ , - . semiaromatic unit which is obtained from the polycondensation ofa diamine and an
aromatic dicarboxylic acid.
25 The diamine comprises advantageously between 4 and 36 carbon atoms.
The diamine may be selected from aliphatic diamines, cycloaliphatic
diamines, and alkylaromatic diamines. These diamines may be linear. They may
also be branched and may comprise at least one alkyl branch on the main chain,
and this alkyl branch may itself be linear or branched.
30 When the diamine is aliphatic and linear, it conforms to the formula
H2N-(CH&NH2. It may therefore be selected from butanediamine (x = 4), pentanediamine
(x = 5), hexanediamine, also called hexamethylenediamine (x = 6),
heptanediamine (x = 7), octanediamine (x = 8), norlanediamine (x = 9),
decanediamine (x = lo), undecanediamine (x = l l ) , dodecanediamine (x = 12),
tridecanediamine (x=13), tetradecanediamine (x=14), hexadecanediamine
(x = 16), octadecanediamine (x = 18), octadecenediamine (x = 18), eicosanediamine
(x = 20), docosanediamine (x = 22), and the diarnines obtained from fatty acids.
Diamines of these kinds all have the advantage that they may be biobased and
include organic carbon from biomass, as may be determined in accordance with
standard ASTM D6866. . ,
When the diamine is cycloaliphatic, it may be selected from bis(3,Sdialkyldiaikyl-
4-aminocyclohexyl)propane. bis(3,5dialkyl-4-amino-cyclohexyl)butane bis(3-
methyl-4-aminocyclohexyl)methane (BMACM or MACM), p-bis(aminocyclohexyI)-
methane (PACM) and isopropylidenedi(cyclohexylamine) (PACP): The cycloaliphatic
diamine may also include the following carbon skeletons: norbornylmethane,
cyclohexylmethane, dicyclohexylpropane, di(methylcyclohexyl),
di(methylcyclohexyl)propane. A nonexhaustive list of these cycloaliphatic diamines
is given in the publication "Cycloaliphatic Amines" (Encyclopaedia of Chemical
Technology, Kirk-Othrner, 4th Edition (1992), pp. 386-405).
When the diamine is alkylaromatic, it may be selected from l,&xylylene
diarnine and I ,4-xylylene diamine. ... ~- ~
Advantageously, the diamine is an aliphatic diamine.
Preferedly, the diamine is a linear aliphatic diamine.
The aromatic dicarboxylic acid may be selected from terephthalic acid
(coded T), isophthalic acid (coded I), phthalic acid, and naphthalene acids. The
aromatic dicarboxylic acids which have just been cited may also include one or more
alkyl branches, and these alkyl branches may themselves be linear or branched.
Included accordingly is 2-methylterephtalic acid.
Advantageously, the semiaromatic polyamide has a melting temperature of
greater than 240QC, advantageously of between 240°C and 31O0C, and more
particularly of belween 260°C and 280°C.
More particularly preferedly, the aromatic dicarboxylic acid is terephthalic
acid (T).
According to one particular version of the invention, the semiaromatic
polyamide may comprise more than 50mol% of first repeating unit(s),
advantageously more than 60 mol%.
It is possible more particularly to consider the use of a semiaromatic
5 polyamide composed of 100 mol% of one or more first repeating units.
More particularly, according to a first aspect of the invention, this
semiaromatic polyamide may be a homopolymer composed only of first repeating
units obtained from the polycondensation reaction of a diamine and an aromatic
dicarboxylic acid.
10 Accordingly, the semiaromatic polyamide may be selected from the
homopolyamides6.T, 9.T, 10.T, 11.T, 12.T, 14.T, 18.T, 6.1, 9.1, 10.1, 11.1, 12.1, 14.1,
and 18.1.
According to a second aspect of the invention, this semiaromatic polyamide
may be a copolymer composed of first repeating units obtained from the
15 polycondensation reaction of a diamine and two aromatic dicarboxylic acids, or from
the polycondensation reaction of two diamines and an aromatic dicarboxylic acid.
Accordingly, in the first case, the semiaromatic polyamide may be selected
from the copolyamides 6.Tl6.1, 9.T19.1, 10.TIlO.l, 11.Tl11.l, and 12.Tl12.1. In the
second case, the semiaromatic polyamide may be selected from the copolyamides
20 . 6. .Tl9.T. 6.TllO.T, 6.T/ll.T, 6.T/12.T, 9.Tl10.T, 9.T/11.T, 9.Tl12.T, 10.Tl1. 1. .T,
10.TlI2.T, and 11.Tl12.T. A similar list may be drawn up by replacing the
terephthalic acid (T) with isophthalic acid (I).
According to a third aspect of the invention, this semiaromatic polyamide
may be a copolymer comprising first repeating units obtained from the, . .
25 polycondensation reaction of at least two diamines and at least two aromatic
dicarboxylic acids.
In addition to this at least one first, semiaromatic repeating unit, which has
just been detailed and which is obtained from the polycondensation of a diamine
and an aromatic dicarboxylic acid, the semiaromatic polyamide in the composition of
30 the invention may also comprise at least one second repeating unit, this second
repeating unit being necessarily other than the first repeating unit or units.
This second repeating unit may be selected from the group consisting of a
unit obtained from an aminocarboxylic acid, a unit obtained from a lactam, and a unit
conforming to the formula (Ca diamine).(Cb difunctional acid), where "a" represents
the number of carbon atoms in the diamine and " b represents the number of carbon
atoms in the difunctional acid.
Advantageously, a and b areeach between 4 and 36.
When this second repeating unit is obtained from an aminocarboxylic acid,
5 this aminocarboxylic acid may be selected from 9-aminononanoic acid (9)'
10-aminodecanoic acid (lo), 10-aminoundecanoic acid (I?), 12-qminododecanoic
acid (12), and I I-aminoundecanoic acid (1 1). The aminocarboxylic acid may also be
branched. A possible example is N-heptyl-I I-aminoundecanoic acid.
When this second repeating unit is obtained ~ ~ from a lactam, this lactam may
10 be selected from pyrrolidinone, 2-piperidinone, enantholactam, caprylolactam,
pelargolactam, decanolactam (lo), undecanolactam (1 I), and lauryllactam (12).
When this second repeating unit is a unit conforming to the formula (Ca
diamine).(Cb difunctional acid), it is obtained from the polycondensation of a
diamine, the Ca diamine, and a dicarboxylic acid, the Cb difunctional acid, with the
15 proviso that this dicarboxylic acid is not an aromatic dicarboxylic acid.
This Ca diamine may be selected from aliphatic diamines, cycloaliphatic
diamines, and alkylaromatic diamines. These Ca diamines may be linear. They may
also be branched and may include at least one alkyl branch on the main chain, and
this alkyl branch may itself be lirlear or branched.
20 T. he diamines described above for preparing the first repeating unit may . .
also be used as Ca diamine for obtaining the second repeating unit. Reference is
therefore made to the paragraphs above relating to the diamines that may be used
to obtain the first repeating unit for examples of Ca diamines which may be used for
producing thesecond repeating unit. . .
25 The dicarboxylic acid (Cb difunctional acid) employed for obtaining the
second repeating unit may be selected from aliphatic dicarboxylic acids and
cycloaliphatic dicarboxylic acids. These dicarboxylic acids may be linear. They may
also be branched and may comprise at least one alkyl branch on the main chain,
and this alkyl branch may itself be linear or branched.
30 When the dicarboxylic acid (Cb difunctional acid) is aliphatic and linear, it
may be selected from succinic acid (4), pentanedioic acid (5), adipic acid (G),
heptanedioic acid (7), octanedioic acid (8), azelaic acid (9), sebacic acid (lo),
undecanedioic acid (I?), dodecanedioic acid (12), brassylic acid (13),
tetradecanedioic acid (14), hexadecanedioic (16), octadecanedioic acid (18),
octadecenedioc acid (18), eicosanedioic acid (20), docosanedioic acid (22), and
fatty acid dimers containing 36 carbons.
The fatty acid dimers referred to above are dimerized fatty acids obtained
by oligomerization or polymerization of unsaturated monobasic fatty acids with a
5 long hydrocarbon chain (such as linoleic acid and oleic acid), as described in
particular in document EP 0 471 566.
When the dicarboxylic acid (Cb difunctional acid) is cycloaliphatic, it may
comprise the following carbon skeletons: norbornyl methane, cyclohexane,
cyclohexylmethane, dicyclohexylmethane, dicyclohexylpropane, di(methylcyclo-
10 hexyl), di(methylcyclohexyl)propane.
Accordingly, the second repeating unit of the semiaromatic polyamide may
denote, in particular, the following Units: 6, 11, 12, 6.10, 6.12, 6.14, 6.18, 10.10,
10.12, 10.14, 10.18, and 12.12.
According to a fourth aspect of the invention, this semiaromatic polyamide
15 may be a copolymer composed of first repeating units obtained from the
polycondensation reaction of a diamine and an aromatic dicarboxylic acid, and
second repeating units obtained alternatively from an aminocarboxylic acid, or from
a lactam, or from the polycondensation of a Ca diamine and a Cb difunctional acid
as described above.
20 Among the combinations to which consideration may be given, the
following copolyamides are of particularly marked interest: these are copolyamides
conforming to one of the formulae selected from 11/6.T, 12/6.T, 6.10/6.T, 6.12/6.T,
10.1016.T, 10.12/6.T, 12.12/6.T, 11/9.T, 12/9.T, 6.10/9.T, 6.12/9.T, 10.1019.T,
10.12/9.T, 12.12/9.T, / O T 12/lOT 6.10110.T, 6.12/10.T, 10.10/10.T,
25 10.12/10.T, and 12.12/10.T.
According to a fifth aspect of the invention, this semiaromatic polyamide
may be a copolymer comprising first repeating units obtained from the
polycondensation reaction of at least one diamine and at least one aromatic
dicarboxylic acid, and second repeating units obtained from at least one amino-
30 carboxylic acid, at least one lactam, and/or from the polycondensation of a Ca
diamine and a Cb difunctional acid as described above.
Among the multiplicity of combinations to which consideration may be
given, mention may be made in particular of the copolyamides conforming to one of
the formulae selected from:
- 6/11110.T, 6112110.T, 11112/10.T, 11/6.10110.T, 12/6.10110.T, 11/10.6110.T,
12/10.6/10.T, these copolyamides all comprising a first repeating 10.T unit
and two second repeating units,
- 6/6.T/IO.T. 11/6.Tl10.T, 12/6.TIlO.T, these copolyamides all comprising
two flrst repeating 6.T and 10.T units, and a second repeating unit,
- 1119.Tl9.1, 1219.Tl9.1, 11110.T110.l, 12110.T110.1, these copolyamides all
comprising two first repeating units and a second repeating unit,
- 6/11/6.TllO.T, 11/12/6.T/10.T, these copolyamides both comprising first
repeating 6.T and 10.T units, and two second repeating units.
10 In the context of the present invention, it is possible advantageously to use
first and, where appropriate, second repeating units which are or will be obtained,
entirely or partially, from diamines, dicarboxylic acids, aminocarboxylic acids andlor
lactams which are biobased, in other words containing organic carbon originating
from biomass, as may be determined in accordance with standard ASTM D6866.
15 The crosslinked polvolefin
The composition according to the invention comprises at least one
crosslinked polyolefin, said crosslinked polyolefin being present as a phase
dispersed in the matrix formed by the semiaromatic polyamide(s).
This crosslinked polyolefin originates from the reaction of two or of at least
20 two products having groups which are reactive with one another.
More particularly, the crosslinked polyolefln is obtained from at least one
product (A) comprising an unsaturated epoxide and from at least one product (B)
comprising an unsaturated carboxylic anhydride.
Product (A) is advantageously a polymer comprising an unsaturated
25 epoxide, this unsaturated epoxide being introduced into said polymer either by
grafting or by copolymerization.
The unsaturated epoxide may in particular be selected from the following
epoxides:
- aliphatic glycidyl ethers and esters such as allyl glycidyl ether, vinyl glycidyl
ether, glycidyl maleate and itaconate, glycidyl acrylate and methacrylate,
and
alicyclic glycidyl ethers and esters such as 2-cyclohexen-I-yl glycidyl ether,
diglycidyl cyclohexene-4,5-dicarbohlate, glycidyl cyclohexene-4-
carboxylate, glycidyl 5-norbornene-2-methyl-2-carboxylate, and diglycidyl
endo-cis-bicyclo[2.2.l]hept-5-ene-2,3dicarboxylate.
According to a first form, the product (A) is a polyolefin grafted with an
unsaturated epoxide. By polyolefin is meant a homopolymer or copolymer
5 comprising one or more olefin units such as ethylene, probylene, but-I-ene, or any
other alpha-olefin units. Examples of polyolefin include the following:
- polyethylene and, in particular, low density polyethylene (LDPE), high
density polyethylene (HDPE), linear low density polyethylene (LLDPE), and
very low density polyethylene (VLDPE); polypropylene;
ethylenelpropylene copolymers; elastomeric polyolefins such as ethylenepropylene
(EPR or EPM) or ethylene-propylenediene monomer (EPDM);
or else metallocene polyethylenes obtained by single-site catalysis;
- styrenelethylene-butenelstyrene block copolymers (SEBS);
styrenelbutadienelstyrene block copolymers (SBS);
styrenelisoprenelstyrene block copolymers (SIS); or else styrene/ethylenepropylenelstyrene
block copolymers;
- copolymers of ethylene and at least one product selected from salts of
unsaturated carboxylic acids, esters of unsaturated carboxylic acids, and
vinyl esters of saturated carboxylic acids. The polyolefin may in particular
be a copolymer of ethylene and ~alk.yl (meth)acrylate or a copolymer of
ethylene and vinyl acetate.
According to a second form, product (A) is a copolymer of alpha-olefin and
an unsaturated epoxide and, advantageously, a copolymer of ethylene and an
unsaturated epoxide. Advantageously, the amount of unsaturated epoxide.may
25 represent up to 15% by weight of the copolymer (A), with the amount of ethylene in
turn representing at least 50% by weight of the copolymer (A).
Mention may be made more particularly of copolymers of ethylene, a
saturated carboxylic acid vinyl ester, and an unsaturated epoxide, and also
copolymers of ethylene, an alkyl (meth)acrylate, and an unsaturated epoxide.
30 Preferably, the alkyl (meth)acrylate comprises from 2 to 10 carbon atoms. Examples
of alkyl acrylates or methacrylates which can be used are, in particular, methyl
acrylate, methyl methacrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, and
2-ethylhexyl acrylate.
According to one advantageous version of the invention, product (A) is a
copolymer of ethylene, methyl acrylate, and glycidyl methacrylate, or a copolymer of
ethylene, n-butyl acrylate, and glycidyl methacrylate. It will be possible in particular
to use the product sold by Arkema under the name Lotadere AX89OO.
5 According to another form of the invention, product (A) is a product having
two epoxide functions, such as, for example, the diglycidyl ether of bisphenol A
(DGEBA).
Product (€31 is advantageously a polymer comprising an unsaturated
carboxylic anhydride, this unsaturated carboxylic anhydride being introduced into
10 said polymer either by grafting or by copolymerization.
Examples of unsaturated dicarboxylic anhydrides which can be used as
constituents of product (8) are, in particular, maleic anhydride, itaconic anhydride,
citraconic anhydride, and tetrahydrophthalic anhydride.
According to a first form, product (B) is a polyolefin grafted with an
15 unsaturated carboxylic anhydride. As was seen above, a polyolefin is a
homopolymer or copolymer comprising one or more olefin units such as ethylene,
propylene, but-I-ene, or any other alpha-olefin units. This polyolefin may in
particular be selected from the examples of polyolefins listed above for product (A),
when the latter is a polyolefin grafted with an unsaturated epoxide.
20 According to a second form, product (B) is a. .co polymer of alpha-olefin and
of an unsaturated carboxylic anhydride, and, advantageously, a copolymer of
ethylene and an unsaturated carboxylic anhydride. Advantageously, the amount of
unsaturated carboxylic anhydride may represent up to 15% by weight of the
. . . . . copolymer (B), with the amount of ethylene itself representing at-least 50% by
25 weight of the copolymer (B).
Mention may be made more particularly of copolymers of ethylene, a
saturated carboxylic acid vinyl ester, and an unsaturated carboxylic anhydride, and
also of copolymers of ethylene, an alkyl (meth)acrylate, and an unsaturated
carboxylic anhydride. Preferably, the alkyl (meth)acrylate comprises from 2 to 10
30 carbon atoms. The alkyl acrylate or methacrylate may be selected from those cited
above for product (A).
According to one advantageous version of the invention, product (B) is a
copolymer of ethylene, an alkyl (meth)acrylate, and an unsaturated carboxylic
anhydride. Preferably, product (6) is a copolymer of ethylene, ethyl acrylate, and
maleic anhydride, or a copolymer of ethylene, butyl acrylate, and maleic anhydride.
It will in particular be possible to use the products sold by Arkema under the names
~otader"4700 and Lotader 3410.
It would not be a departure from the scope of the invention if a part of the
maleic anhydride in the product (B), according to the first and second forms
described above, was partly hydrolyzed.
According to the invention, the weight amounts of product (A) and of
product (B), which are written respectively as [A] and [B], are such that the ratio
[B]I[A] is between 3 and 14 and, advantageously, between 4 and 9.
In the composition according to the invention, the crosslinked polyolefin
may also be obtained from products (A) and (8) as described above and from at
least one product (C), this product (C) comprising an unsaturated carboxylic acid or
an alpha,omega-aminocarboxylic acid.
Product (C) is advantageously a polymer comprising an unsaturated
carboxylic acid or an alphanomega-aminocarboxylic acid, with one or other of these
acids being introduced into said polymer by copolymerization.
Examples of unsaturated carboxylic acids which can be used as
constituents of product (C) are, in particular, acrylic acid, methacrylic acid, and the
carboxylic anhydrides cited above as constituents of product (B), these anhydrides
being completely hydrolyzed.
Examples of alpha,omega-aminocarboxylic acids which can be used as
constituents of product (C) are, in particular, 6-aminohexanoic acid, ll-aminoundecanoic
acid, and 12-aminododecanoic acid.
. . . , Product (C) may be a copolymer of alpha-olefin and an unsaturated
carboxylic acid, and, advantageously, a copolymer of ethylene and an unsaturated
carboxylic acid. Included in particular are the completely hydrolyzed copolymers of
product (6).
According to one advantageous version of the invention, product (C) is a
copolymer of ethylene and (meth)acrylic acid, or a copolymer of ethylene, an alkyl
(meth)acrylate, and (rneth)acrylic acid. The amount of (meth)acrylic acid may
represent up to 10% by weight and, preferably, from 0.5 to 5% by weight of the
copolymer (C). The amount of alkyl (meth)acrylate is generally between 5 and 40%
by weight of the copolymer (C).
Preferably, product (C) is a copolymer of ethylene, butyl acrylate, and
acrylic acid. It will be possible in particular to use the product sold by BASF under
the name Lucalenem 31 10.
According to the invention, the weight amounts of product (A), of product
5 (B), and of product (C), which are written respectively as [A], [B] and [C], are such
that the ratio [BY([A]+[C]) is between 1.5 and 8, the weight amounts of products (A)
and (B) being such that [C] 5 [A].
Advantageously, the ratio [B]I([A]+[C]) is between 2 and 7.
The dispersed crosslinked polyolefin phase may of course come from the
10 reaction of one or more products (A) with one or more products (B) and, where
appropriate, with one or more products (C).
As already described in document WO 2011/015790, it is possible to use
catalysts which accelerate the reaction between the reactive functions of the
products (A) and (5). Reference will therefore be made to the teaching of said
15 document with regard to examples of catalysts, which may be used in a weight
amount of between 0.1 and 3% and, advantageously, between 0.5 and 1% of the
total weight of the products (A), (5) and, where appropriate, (C).
The composition according to the invention comprises, relative to the total
weight of the composition:
20 - from 45 to 95% by weight, advantageously from 55 to 90% by weight, of
semiaromatic polyamide(s), and
- from 5 to 55% by weight, advantageously from 10 to 45% by weight, of
crosslinked polyolefin(s).
.. , .. . This composition may' besolely composed of these two.classesof- -"~
25 compounds, namely at least one semiaromatic polyamide, and at least one
crosslinked polyolefin.
However, the composition may also comprise other compounds in addition
to those which have just been cited. The composition of the invention may, in
particular, further comprise at least one additive andlor at least one further polymer.
The additives
The composition of the invention may further comprise at least one additive
as well.
This additive may in particular be selected from processing aids,
plasticizers, fillers, stabilizers (UV andlor heat), dyes, mold release agents, flame
retardants, surfactants, optical brighteners, antioxidants, and mixtures thereof.
Among the processing aids, mention may be made of stearates, such as
5 calcium or zinc stearates, natural waxes, and polymers comprising
tetrafluoroethylene (TFE).
The weight proportion of processing aids is conventionally between 0.01
and 0.3% by weight, advantageously between 0.02 and 0.1% by weight, relative to
the total weight of the composition.
10 Among the plasticizers, use may be made in particular of
benzenesulfonamide derivatives, among them n-butylbenzenesulfonamide (BBSA).
The weight proportion of plasticizer may represent up to 25% by weight and
is advantageously between 3 and 20% by weight, relative to the total weight of the
composition.
15 The fillers include silica, graphite, expanded graphite, carbon black, carbon
fibers, glass beads, kaolin, magnesia, slags, talc, nanofillers (carbon nanotubes),
pigments, metal oxides (titanium oxide), metals, and fibers (aramids, glass, carbon).
Depending on the nature of the fillers, the amount thereof may represent up
to 50% by weight, advantageously, up to 30% by weight, of the total weight of the
20 composition.
The further ~olvmers
A composition in accordance with the invention may further comprise one
or more further polymers, and in particular at least one third polymer, such a
.polymer'being different from the semiaromatic polyamide(s) 'and from' the , .. , ,
25 crosslinked polyolefin(s) referred to above.
Advantageously, this further polymer may in particular be selected from a
polyamide, a polyamide-block-ether, a polyetheramide, a polyesteramide, a
polyphenylene sulfide (PPS), a polyphenylene oxide (PPO), a noncrosslinked
polyolefin (in contrast to the crosslinked polyolefin considered above), a
30 fluoropolymer, and mixtures thereof. With regard to the noncrosslinked polyolefins,
mention may be made of the polyolefins described in the section on "the crosslinked
polyolefin", in other words products (A), (B), or (C), which are in that case used
alone so as not to crosslink, it being noted that these noncrosslinked polyolefins are
known, moreover, as impact modifiers.
The further polymer may likewise be selected from starch, which may be
modified andlor formulated, cellulose or its derivatives, such as cellulose acetate or
5 cellulose ethers, polylactic acid, polyglycolic acid, and polyhydroxyalkanoates.
Preferably, the further polymer is selected from aliphatic polyamides and
polyamide-block-ethers.
The composition may contain up to 20% by weight, relative to the total
weight of the composition, of at least one further polymer.
10 The invention also relates to a process for preparing a composition as
defined above. According to this process, the composition may be prepared by any
method allowing a homogeneous mixture to be obtained, such as extrusion in the
melt state, compacting, or else roll milling.
More particularly, the composition of the invention may be prepared by
15 mixing in the melt state the semiaromatic polyamide(s) and the products (A), (B),
and optionally (C) for producing the crosslinked polyolefin(s).
The optional additives andlor further polymers may for their part be
introduced either at the same time as the semiaromatic polyamide(s) and products
(A), (B), and, where appropriate, (C), or in a subsequent step.
20 Advantageously, the composition may be obtained in pellet form by
compounding, in particular by means of a twin-screw extruder, a co-kneading
apparatus, or an internal mixer. These pellets of the composition according to the
invention obtained by the above-described preparation process may subsequently
be converted using tools known=to the skilled person-(such as an injection molding
25 machine or an extruder) to the form of filaments, tubes, films andlor moldings.
The process for preparing the composition of the invention may also use a
twin-screw extruder which, without intermediate pelletizing, feeds an injection
molding machine or an extruder for the production of filaments, tubes, films andlor
moldings.
30 The invention therefore also relates to a material or article obtained from a
composition as defined above by a known conversion process such as injection
molding, extrusion, extrusion blow molding, coextrusion, or multiple injection.
The invention likewise relates to the use of a composition as described
above for forming a structure. This structure may be single-layer when formed only
from the composition of the invention. This structure may also be multilayer, when it
comprises at least two layers and when at least one of these different layers is
5 composed of the composition of the invention.
The invention likewise relates to a component formed wholly or partly from
the composition of the invention. This component may comprise the immediately
aforementioned single-layer or multilayer structure. Such a component may in
particular be an injection molded component and, more particularly, an extruded,
10 coextruded, or extrusion-blow molded component. It may in particular take the form
of a tube, a pipe, a reservoir, fibers, a film, a sheet, or a plate.
The invention relates, lastly, to the use of such a component for storing or
conveying a fluid. A fluid of this kind may in particular be selected from a fuel, a
refrigerant, a cooling liquid, a brake fluid, an oil, a lubricant, a hydraulic fluid, a liquid
15 based on urea solution, a chemical product, water, or else a gas or gaseous
emanations or vapors, which gas may be at overpressure or at underpressure.
The component formed wholly or partly from the composition of the
invention may in particular be used for producing all or part of components of
surgical equipment, packaging, sports or leisure articles. This component may also
20 be used for producing all"or part of elements of electrical and electronic goods,
industrial equipment for the storage, transport, or transfer of fluids such as those
listed above, or else automobile or truck equipment.
Other objectives and advantages of the present invention will emerge from
~ ~
a reading of the examples which follow, which are given as an indication and in no
25 way as a limitation, and from an examination of the figures, it being specified that:
- figure 1 is a scanning electron micrograph (SEM) of a sample of
composition 9, following dissolution of the dispersed, crosslinked
polyolefin phase by treatment with xylene at 150°C for 30 minutes, and
- figure 2 is a scanning electron micrograph (SEM) of a sample of
composition 1, following dissolution of the dispersed, crosslinked
polyolefin phase by treatment with xylene at 150°C for 30 minutes,
these two'micrographs being on the same scale.
[Examples]
Formulation of the compositions
The compositions tested were prepared from the following products:
11110.T: semiaromatic polyamide, with a molar 11110.T ratio of 0.7, obtained by
polycondensation of 11-aminocarboxylic acid, 1,lO-decanediamine, and
terephthalic acid, having a glass transition temperature Tg of 88"C, a
melting temperature Tf of 260°C, an intrinsic viscosity of 1.22
(measured according to standard IS0 307), and an enthalpy of fusion of
47 Jlg
10 Lotader AX8900: copolymer of ethylene, methyl acrylate, and glycidyl methacrylate
(EVMNGMA - 6812418 by weight), corresponding to product (A)
Lotader 4700: copolymer of ethylene, ethyl acrylate, and maleic anhydride
(EtlENMAH - 6913011 by weight), corresponding to product (8)
Lotader 3410: copolymer of ethylene, butyl acrylate, and maleic anhydride
15 (EtlBNMAH - 8111613 by weight), corresponding to product (B)
Lucalene 3110: copolymer of ethylene, butyl acrylate, and acrylic acid (EVBNAA
- 881814 by weight), corresponding to product (C)
Iodine 201: antioxidant additive based on KI and Cul
Compositions 1 to 9 were all prepared on a twin-screw extruder, according
20 to the formulations set out in detail in table I below, the amount of crosslinked
polyolefin being equal to 30% by weight of the total weight of each of compositions 1
to 9.
Compositions 4, 5, and 7 to 9 are compositions in accordance with the
invention, whereas compositions 1, 2, 3,. and 6 are compositions outside the
25 invention. In particular, composition 2 corresponds to the composition E described in
document WO 201 11015790.
Tests conducted
The morphology of compositions 1 to 9 was studied by scanning electron
microscopy (SEM). The volume-average diameters of the nodules of crosslinked
30 polyolefin, denoted Dv, were measured and reported in table 1.
The index of flow in the melt state, also called fluidity index or Melt Flow .
Index (MFI), was measured in accordance with standard ASTM Dl238 at 300°C,
under a weight of 5 kg, and the values reported in table 1.
Platelplate viscosity measurements were carried out at 300°C (10 radls).
The initial values and values after 30 minutes as well as the difference between the
values at 30 minutes and initial values are reported in table 1.
Compositions 1 to 9 were then extruded in the form of tubes with a
diameter of 8 mm and a thickness of 1 mm (8 * 1 mm). During this extrusion
conversion, deposits ("drool") was observed to form on the extrusion die. The
appearance of the inner and outer surfaces of the extruded tubes was also
examined. The observations are reported in table 1 below, in which the following
abbreviations each has the following meanings:
- "-": the surfaces of the tubes are rough and there is die drool;
- "ithse su:rfa ces of the tubes are smooth but matt and there is little die
drool; and
- "++": the surfaces of the tubes are smooth and shiny and there is very
little die drool, or none at all.
It is observed that, in contrast to comparative compositions 1 and 2,
inventive compositions 4, 5, and 7 to 9 all have a fine morphology, with nodules of
crosslinked polyolefin that have a volume-average diameter Dv whose value is less
than 1 pm. Reference may be made in particular to figure 1, which clearly shows
the particularly fine dispersion of the nodules in composition 9, relative to that of the
nodules in composition 1 as illustrated in figure 2.
In the case of compositions 1 to 5 on the one hand and of compositions 6
to 9 on the other, it is seen that the greater [B]l[A] or [B]I([A]+[C]), the finer the
morphology (Dv). Similarly, the higher [B]I[A] or [B]I([A]+[C]), the better the
rheology, the reason is that the composition is more fluid and more stable (meaning
5 that it does not change very much under heat); its conversion by extrusion is easier.
Furthermore it is observed that in the extrusion conversion of inventive
compositions 4, 5, and 7 to 9, there was no (or very little) development of drool on
the extrusion die, and that the tubes extruded from these compositions 4, 5, and 7
to 9 all had an inner surface and an outer surface that were smooth and shiny.
1. A composition comprising at least one semiaromatic polyamide and at least
5 one crosslinked polyolefin, the crosslinked polyolefin being obtained from:
- at least one product (A) comprising an unsaturated epoxide, and
- at least one product (6) comprising an unsaturated carboxylic anhydride,
characterized in that the weight amounts of (A) and (B), written respectively as [A]
and [B], are such that the ratio [B]I[A] is between 3 and 14, advantageously between
10 4 and 9.
2. The composition as claimed in claim 1, characterized in that the crosslinked
polyolefin is obtained from the products (A), (B), and from at least one product (C)
comprising an unsaturated carboxylic acid or an alpha,omega-aminocarboxylic acid,
the weight amounts of (A), (B) and (C), written respectively as [A], [B] and [C]b,e ing
15 such that [C] <[A] and the ratio [B]I([A]+[C]) being between 1.5 and 8,
advantageously between 2 and 7.
3. The composition as claimed in claim 1 or 2, characterized in that the product
(A) is a polyolefin grafted with an unsaturated epoxide or a copolymer of alpha-olefin
and an unsaturated epoxide. . .
20 4. The composit~ona s claimed in claim 3, characterized in that the product (A)
is a copolymer of ethylene, a saturated carboxylic acid v~nyl ester, and an
unsatucated epoxide, or a copolymer of ethylene, an alkyl (meth)acrylate, and an
unsaturated epoxide.
5. The composition as claimed In any one of claims 1 to 4, characterized in that
25 the product (8) is a polyolefin grafted with a carboxylic acid anhydride or a
copolymer of alpha-olefin and a carboxylic acid anhydride.
6. The composition as claimed in claim 5, characterized in that the product (B)
is a copolymer of ethylene, a saturated carboxylic acid vinyl ester, and an
unsaturated carboxylic anhydride, or a copolymer of ethylene, an alkyl
30 (meth)acrylate, and an unsaturated carboxylic anhydride.
7. The composition as claimed in any one of claims 2 to 6, characterized in that
the product (C) is a copolymer of alpha-olefin and an unsaturated carboxylic acid.
8. The composition as claimed in claim 7, characterized in that the product (C)
is a copolymer of ethylene and (meth)aclylic acid, or a copolymer of ethylene, an
5 alkyl (meth)acrylate, and (meth)acrylic acid.
9. The composition as claimed in any one of claims 1 to 8, characterized in that
the semiaromatic polyamide comprises at least one first semiaromatic repeating unit
obtained from the polycondensation of a diamine and an aromatic dicarboxylic acid.
10. The composition as claimed in claim9, characterized in that the
10 semiaromatic polyamide comprises at least one second repeating unit selected from
the group consisting of a unit obtained from an aminocarboxylic acid, a unit obtained
from a lactam, and a unit conforming to the formula (Ca diamine).(Cb difunctional
acid), where a represents the number of carbon atoms in the diamine and b
represents the number of carbon atoms in the difunctional acid.
15 11. The composition as claimed in claim 9 or 10, characterized in that the
semiaromatic polyamide comprises more than 50 mol% of first repeating unit,
advantageously more than 60 mol%.
12. The composition as claimed in any one of claims 1 to 11, characterized in
that it comprises at least one additive selected from processing aids, plasticizers,
20 fillers, stabilizers, dyes, mold release agents, flame retardants, surfactants, optical
brighteners, antioxidants, and mixtures thereof.
13. The composition as claimed in any one of claims 1 to 12, characterized in
that the composition comprises at least one additional polymer selected from the
group consisting of a polyamide, a polyamide-block-ether, a polyetheramide, a
25 polyesteramide, a polyphenyiene sulfide, a polyphenylene oxide, a noncrosslinked
polyolefin, and a fluoropolymer.
14. A process for preparing the composition as defined in any one of claims 1 to
11, characterized in that the composition is prepared by melt-state mixing the
semiaromatic polyamide(s) and the products (A), (B), and optionally (C) for obtaining
.
the crosslinked polyolefin(s).
15. The use of a composition as defined in any one of claims 1 to 13 for making
a single-layer structure or at least one layer of a multilayer structure.