Semi-aromatic-polyamide-based flexible composition, process for preparing
same and uses thereof
The present invention relates to a flexible composition comprising at least
5 one semiaromatic polyamide, at least one crosslinked polyoiefin, and at least one
plasticizer, 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.
r h e 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
15 produced from them.
For optimum adaptation of the thermomechanical properties of these
components, the semiaromatic polyamide-based compositions from which these
components are manufactured may comprise one or more other polymers andlor
additives.
20 Document EPI 505099A2 describes, in particular, a polyamide
composition comprising from 60 to 99.5% by weight of at least one copolyamide and
from 0.5 to 40% by weight of at least one product selected from plasticizers.
nanofillers, polyolefins, crosslinked polyolefins, and additives, the weight amounts
being given relative to the total weight of the composition. This composition is
25 described as being a flexible composition with low water uptake, which has a
superior thermomechanical performance and is easy to convert.
More particularly, looking at the tables in said document EP 1 505 099 A2,
it is observed that the flexural modulus of a test specimen produced from a
semiaromatic polyamide composition can be lowered by adding a plasticizer andlor
30 a crosslinked polyolefin.
The addition of a plasticizer to a semiaromatic polyamide allows the flexural
modulus to be lowered significantly. However, it is observed that, while the flexural
modulus reduces in line with increased weight plasticizer content of the
semiaromatic polyamide composition, there is also a proportional reduction in the
low-temperature impact strength properties (as evaluated by the measurement of
the Charpy impact at -40°C). It is found, furthermore, that the higher the plasticizer
content, the greater the formation of fumes during extrusion of a composition of this
5 kind comprising a semiaromatic polyamide and a plasticizer.
The addition of a crosslinked polyolefin to a semiaromatic polyamide also
allows the flexural modulus to be lowered. However, in order to reach flexural
modulus values of the order of 600 to 700 MPa, it is necessary to add at minimum
from 40 to 45% by weight of the total weight of the composition formed by the
10 semiaromatic polyamide and the crosslinked polyolefin. With weight proportions of
this kind, a non-nodular alloy morphology (phase inversion) is obtained which rules
out the conversion of such a composition by extrusion. Obtaining an extruded tube
is therefore impossible.
The addition of a crosslinked polyolefin and of a plasticizer to a
15 semiaromatic polyamide is an alternative route which also permits a very significant
lowering of the flexural modulus. There again, however, it is observed that the lowtemperature
impact strength properties are not satisfactory. Moreover, in order to
enhance these low-temperature mechanical properties, an aliphatic polyamide is
added, the effect of which is to stiffen the material.
20 Accordingly there is a genuine need to find new compositions that allow the
production of components exhibiting in combination:
- a very good high-temperature strength, particularly at service temperatures
of at least l6O0C,
- a very good aging resistance, which may in particular be evaluated by
thermooxidative measurements to determine the time taken for the
elongation at break of samples to reduce by half,
- very good mechanical properties, more particularly a low-temperature
impact strength as manifested by a Charpy impact value at -40°C of at least
greater than or equal to 7 kJIm, this value being measured in accordance
with standard IS0 179-leA, and
- a flexural modulus of less than or equal to 800 MPa, advantageously less
than or equal to 700 MPa, and, preferably, less than or equal to 600 MPa,
this modulus being measured in accordance with standard IS0 178-93.
Furthermore, all of the properties which have just been listed must not be
achieved at the expense of a conversion process by extrusion, coextrusion, or
extrusion-blow molding. In other words, the aim is to obtain extruded (coextruded or
extrusion-blow molded) components, more particularly tubes, whose inner and outer
5 surfaces have a uniform and smooth appearance. The reason is that an irregular
appearance to these outer surfaces of the extruded tubes may have detrimental
consequences for the mechanical properties of the tubes.
A further aim is to prevent the formation of fumes during this conversion
step.
10 [Brief description of the invention]
Surprisingly, the applicant has found that this dual need, in terms of
properties and of conversion, is achieved by a composition of the aforementioned
type, namely a composition comprising at least one semiaromatic polyamide, at
least one plasticizer, and at least one crosslinked polyolefin, the crosslinked
15 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.
According to the invention, the composition comprises the following
respective weight proportions of the compounds which have just been cited, the
20 weight percentages being given relative to the total weight of the composition:
- from 33 to 40% by weight of at least one crosslinked polyolefin as defined
above,
- from 3 to 10% by weight of at least one plasticizer, and
- the rest being made up of at least one semiaromatic polyamide,
25 with weight amounts of (A) and (B), written respectively as [A] and [B], such that the
ratio [B]/[A] is between 3 and 14.
By virtue of this specific selection of respective weight proportions of
crosslinked polyolefin(s), plasticizer(s), and semiaromatic polyamide(s), on the one
hand, and of weight amounts of (A) and (B), on the other hand, the composition
30 according to the invention produces components which exhibit noteworthy
thermomechanical and flexibility properties. Such components, when obtained by
extrusion, have the advantage, moreover, of having smooth outer surfaces. During
this conversion step, there is little or no deposition on the screw andlor on the
extrusion die, also referred to as "die drool", and this represents an advantage for
the production of the tubes and the upkeep of the extrusion equipment.
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 single-
5 layer or multilayer.
The invention relates, lastly, to a component formed entirely or partly from
a composition of the invention, and also to the uses of such a component.
[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-?:I992 "Plastics - Polyamide (PA) molding and extrusion materiais -
Pad I: 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 polvamide
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 of a diamine and an
aromatic dicarboxylic acid.
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-(CH2),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), nonanediamine (x = 9),
decanediamine (x = lo), undecanediamine (x = I I), dodecanediamine (x = 12),
tridecanediamine (x = 13), tetradecanediamine (x = 14), hexadecanediamine
(x = 16), octadecanediamine (x = 18), octadecenediamine (x = 18), eicosanediamine
5 (x = 20), docosanediamine (x = 22), and the diamines 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(3,5-dialkyldialkyl-
4-aminocyclohexyl)propane, bis(3,5-dialkyl-4-amino-cyclohexyl)butane bis(3-
methyl-4-aminocyclohexyl)methane (BMACM or MACM), p-bis(aminocyclohexy1)-
methane (PACM) and isopropylidenedi(cyclohexylamine) (PACP). The cycloaliphatic
diamine may also include the following carbon skeletons: norbornylmethane,
15 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-Othmer, 4th Edition (1992), pp. 386-405).
When the diamine is alkylaromatic, it may be selected from 1,3-xylylene
20 diamine and 1,4-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
25 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 230°C, advantageously of between 230°C and 310°C, and more
30 particularly of between 240°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
homopolyamides 6.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.Tl9.1, IO.T/lO.I, 11.T/11.1, and 12.Tl12.1. In the
second case, the semiaromatic polyamide may be selected from the copolyamides
20 6.T/9.T, 6.T/IO.T, 6.Tlll.T, 6.Tl12.T, 9.TllO.T, 9.Tlll.T, 9.T/12.T, 10.T/Il.T,
10.Tl12.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 bare each 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 (TI), 12-aminododecanoic
acid (12), and 11-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 (IT), 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 linear or branched.
20 The 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 the second repeating unit.
25 The dicarboxylic acid (Cb difunctional acid) employed for obtaining the
second repeating unit may be selected from allphatic dicarboxylic acids and
cycloaliphatic dicarboxylic acids. These dicarboxylic aclds 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 (6),
heptanedioic acid (7), octanedioic acid (8), azelaic acid (9), sebacic acid (lo),
undecanedioic acid (II), 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(methylcyc1ohexyl)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, 1216.T, 6.1016.T, 6.1216.T,
10.1016.T, 10.12/6.T, 12.1216.T, 11/9.T, 12/9.T, 6.1019.T, 6.1219.T, 10.10/9.T,
10.12/9.T, 12.1219.T, 11110.T 12/'10.T, 6.10110.T, 6.12/10.T, 10.10110.T,
25 10.12/10.T, and 12.12110.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:
- 6111110.T, 6112110.T, 11112110.T, 11/6.10110.T, 1216.10/10.T, 11110.6110.T,
12/10.6/10.T, these copolyamides all comprising a first repeating 10.T unit
and two second repeating units,
- 616.T/IO.T, 11/6.TllO.T, 12/6.TllO.T, these copolyamides all comprising
two first repeating 6.T and 10.T units, and a second repeating unit,
- 1119.T19.1, 1219.T19.1, 11/10.Tl10.~, 12110.TIlO.I, these copolyamides all
comprising two first repeating units and a second repeating unit,
- 611 1/6.T/10.T, 11/12/6.T/10.T, these copolyamides both comprising first
repeating 6.T and 10.T units, and two second repeating units.
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 polyolefin
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 polyolefin is obtained from at least one
product (A) comprising an unsaturated epoxide and from at least one product (8)
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-dicarboxylate, glycidyl cyclohexene-4-
carboxylate, glycidyl 5-norbornene-2-methyl-2-carboxylate, and diglycidyl
endo-cis-bicyclo[2.2. Ilhept-5-ene-2,3-dicarboxylate.
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, propylene, 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-propylene-diene monomer (EPDM);
or else metallocene polyethylenes obtained by single-site catalysis;
- styrenelethylene-butenelstyrene block copolymers (SEBS);
styrenelbutadienelstyrene block copolymers (SBS);
styrenel~soprenelstyreneb lock copolymers (SIS); or else styrenelethylenepropylenelstyrene
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 alkyl (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 AX8900.
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 (B) 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 (B) 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 copolymer 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 (B) 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
Lotader"4700 and Lotader' 3410.
It would not be a departure from the scope of the invention if a part of the
5 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.
10 In the composition according to the invention, the crosslinked polyolefin
may also be obtained from products (A) and (B) 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
15 carboxylic acid or an alpha,omega-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
20 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
25 carboxylic acid, and, advantageously, a copolymer of ethylene and an unsaturated
carboxylic acid. Included in particular are the completely hydrolyzed copolymers of
product (B).
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
30 (meth)acrylate, and (meth)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 Lucalene" 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 [B]/([A]+[C]) is between 1.5 and 8, the weight amounts of products (A)
and (B) being such that [C] 2 [A].
Advantageously, the ratio [B]l([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).
It is possible to use catalysts which accelerate the reaction between the
reactive functions of the products (A) and (B). Reference may be made, in particular,
to the teaching of document WO 20111015790 with regard to examples of catalysts,
15 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), (6)
and, where appropriate, (C).
The ulasticizer
The composition according to the invention comprises at least one
20 plasticizer.
This plasticizer may be a plasticizer commonly used in polyamide-based
compositions.
Advantageously, a plasticizer is used which exhibits high thermal stability
so as not to form fumes during steps of mixing of the various polymers and of
25 converting of the resulting composition.
More particularly, this plasticizer may be selected from:
- benzenesulfonamide derivatives such as n-butylbenzenesulfonamide
(BBSA), the ortho and para isomers of ethyltoluenesulfonamide (ETSA),
N-cyclohexyltoluenesulfonamide, and N-(2-hydroxypropyl)benzenesulfonamide
(HP-BSA),
- esters of hydroxybenzoic acids, such as 2-ethylhexyl parahydroxybenzoate
(EHPB) and 2-decylhexyl para-hydroxybenzoate
(HDPB),
- esters or ethers of tetrahydrofurfuryl alcohol, such as oligoethyleneoxytetrahydrofurfuryl
alcohol, and
- esters of citric acid or of hydroxymalonic acid, such as oligoethyleneoxy
malonate.
5 A plasticizer which is preferred on account of its common use is n-butylbenzenesulfonamide
(BBSA).
Another, more particularly preferred plasticizer is N-(2-hydroxypropy1)-
benzenesulfonamide (HP-BSA). The reason is that the latter has the advantage of
preventing the formation of deposits at the screw andlor the extrusion die ("die
10 drool"), during a step of conversion by extrusion.
It is, of course, possible to use a mixture of plasticizers.
The composition according to the invention comprises, relative to the total
weight of the composition:
- from 33 to 40%, advantageously from 35 to 37%, by weight of at least one
crosslinked polyolefin as described above,
- from 3 to lo%, advantageously from 4 to 8%, by weight of at least one
plasticizer, and
- the rest being made up of at least one semiaromatic polyamide.
This composition may be solely composed of these three classes of
20 compounds, namely at least one crosslinked polyolefin, at least one plasticizer, and
at least one semiaromatic polyamide.
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.
25 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, fillers,
stabilizers (UV andlor heat), dyes, mold release agents, flame retardants,
30 surfactants, optical brighteners, antioxidants, and mixtures thereof.
Among the processing aids, mention may be made of stearates, such as
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.
The fillers include silica, graphite, expanded graphite, carbon black, carbon
5 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
composition.
10 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
crosslinked polyolefin(s) referred to above.
15 Advantageously, this furtherpolymer 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
fluoropolymer, and mixtures thereof. With regard to the noncrosslinked polyolefins,
20 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 pol$t6r may likewise be selected from starch, which may be
25 modified andlor formulated, cellulose or its derivatives, such as cellulose acetate or
cellulose ethers, polylactic acid, polyglycolic acid, and polyhydroxyalkanoates.
Preferably, the further polymer is selected from aliphatic polyamides and
polyamide-block-ethers. The aliphatic polyamides include, in particular, long-chain
polyamides such as PA11, PA12, PA6.10, PA6.12, PA6.14, PA1O.lO, PA10.12, and
30 PA12.12.
The composition may therefore contain up to 20% by weight, relative to the
total weight of the composition, of at least one further polymer.
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.
5 More particularly, the composition of the invention may be prepared by
mixing in the melt state the semiaromatic polyamide(s), the plasticizer(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), plasticizer(s),
10 and products (A), (B), and, where appropriate, (C), or in a subsequent step.
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
15 be converted using tools known to the skilled person (such as an injection molding
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
20 moldings.
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
25 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 composed of the composition of
30 the invention. According to one advantageous variant, this multilayer structure may
be reinforced and may comprise at least one layer composed of a braid or of fibers.
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,
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.
5 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 (such
as gasoline, without or without alcohol, or diesel or biodiesel), a refrigerant or
refrigerating fluid (such as, for example, GO2 or a fluorocarbon fluid such as
1, I1,,2 -tetrafluoroethane or 2,3,3,3-tetrafluoropropene, respectively, as commonly
10 designated by the name R-134a or R-1234yf, used in particular in air conditioning
circuits, conditioned-air circuits, or refrigeration circuits), a cooling liquid (such as a
solution based on alcohol andlor water that may be used in the cooling circuit of
engines), a brake fluid, an oil, a lubricant, a hydraulic fluid, a liquid based on urea
solution, a chemical product, water, or else a gas (such as air, alkanes, hydrogen, or
15 carbon dioxide) or gaseous emanations or vapors (originating, for example, from the
engine), 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, or sports or leisure articles. This component may
20 also be used for producing all or part of elements of electrical and electronic goods,
such as solar panels, encapsulated solenoids, roll cages, pumps, multimedia
systems, cables, and wires. More particularly, the cables and wires may be covered
with a layer formed from the composition of the invention, which thus constitutes a
thermal protection sheath.
25 This component comprising the composition of the invention may
advantageously be used for producing some or all of industrial equipment items for
the storage, transport, or transfer of fluids such as those listed above, more
particularly of hot fluids such as air, oil, lubricants, hydraulic fluids, or else petroleum
and compounds thereof. Such equipment may be intended for use in the field of
30 industry in general (for example, for pneumatic or hydraulic lines) and in the field of
the exploitation of petroleum and gas deposits beneath the sea (offshore field).
This component comprising the composition according to the invention may
very advantageously be used for producing all or part of automobile or truck
equipment items. Such items may in particular be tubes, tube connectors, pumps, or
under-hood injection molded components.
More particularly, these automobile or truck equipment items, especially
when present in the form of tubes andlor connectors, may be used in particular:
- in a device for circulating gas, at overpressure or underpressure, such as
an air intake device or engine gas ventilation device, or a braking
assistance device,
- in a device for circulating oil or lubricant, such as an oil cooling device, a
hydraulic device, or a braking device,
- in a device for circulating aqueous or nonaqueous liquid, such as an engine
cooling device or a selective catalytic reduction device,
- in a device for circulating refrigerant or refrigerating fluid, such as an air
conditioning circuit,
- in a device for storage, transport, or transfer (or circulation) of fluids, more
particularly of fuels.
Such items may of course be made antistatic or conducting, by prior
addition of appropriate amounts of conductive fillers (such as carbon black, carbon
fibers, carbon nanotubes, etc.) to the composition of the invention.
This component comprising the composition of the invention may also be
20 used for storing or conveying a fluid as described above, and typically used in a
stationary air conditioning circuit.
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
way as a limitation.
25 [Examples]
Formulation of the compositions
The compositions tested were prepared from the following products:
11110.T: semiaromatic polyamide, with a molar 11/10.T ratio of 0.7, obtained by
polycondensation of I I-aminocarboxylic acid, I,10 -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
PA1 1: homopolyamide obtained by the poiycondensation of I l-aminoundecanedioic
acid, comprising 100% biobased carbon, having a
melting temperature of 185"C, an intrinsic viscosity of 1.0 to 1.6 dllg
(measured in accordance with standard IS0 307), and an enthalpy of
fusion of 60 Jlg
Lotader AX8900: copolymer of ethylene, methyl acrylate, and glycidyl methacryiate
~EUMNGMA - 6812418 by weight), corresponding to product (A)
10 Lotader 4700: copolymer of ethylene, ethyl acrylate, and maleic anhydride
(EVEAIMAH - 6913011 by weight), corresponding to product (B)
Lucal6ne 31 10: copolymer of ethylene, butyl acrylate, and acrylic acid (EtIBAIAA
- 881814 by weight), corresponding to product (C)
BBSA: n-butylbenzenesulfonamide (BBSA)
15 HP-BSA N-(2-hydroxypropyl)benzenesulfonamide (HP-BSA) sold by Proviron
Iodine 201: antioxidant additive based on KI and Cul
Naugard 445: 4,4'-bis(alpha,alpha-dimethylbenzyl)diphenylamine, which is an
antioxidant additive
Compositions 1 to 12 were all prepared on a twin-screw extruder, according
20 to the formulations set out in detail in table 1 below.
Compositions I , 2, and 4 to 12 are compositions in accordance with the
invention, whereas composition 3 is a composition outside the invention.
Tests conducted
The index of flow in the melt state, also called fluidity index or Melt Flow
25 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.
Compositions 1 to 12 were extruded in the form of tubes with a diameter of
8 mm and a thickness of 1 mm (8 * 1 mm). The tubes thus extruded were subjected
to the following tests:
30 - tubes were subjected to tensile tests in accordance with standard
IS0 527 for determining the elongations at break;
- tubes were subjected to the impact test at -40°C in accordance with the
VW protocol drawn up by Volkswagen in accordance with standard
TL 524 35. The percentage breakage is shown accordingly in table 1;
- tubes were aged in air at 170°C, then subjected to impact at -40°C in
accordance with standard DIN 74324. The half-life (in hours) was
recorded accordingly, and corresponds to the time after which 50% of
the tubes tested suffered breakage (see table 1).
Compositions 1 to 12 were injection molded in the form of bars, in
accordance with standard IS0 179. These resulting bars were subsequently
10 conditioned and kept for two weeks at 50% humidity. The bars were then subjected
to the following tests:
- the flexural modulus of these bars was measured in accordance with
standard IS0 178, and the values obtained have been reported in
table 1.
- bars were notched and then tested in Charpy pendula impact in
accordance with standard IS0 179-leA. The energy absorbed by the
bars, expressed in kJ/m2, was measured at 23°C and -40"C,
respectively, and the corresponding values have been reported in
table 1 below.
The appearance of the inner and outer surfaces of the tubes extruded from
compositions 1 to 12 was examined, and it was observed that the surfaces of all of
the extruded tubes are smooth and glossy. Moreover, during the extrusion step, no
fumes could be obse~ved to form. Examination of the extrusion die, moreover,
Charpy impact
+23"C
(kJ/m2)
Charpy impact -40°C
(kJ/m2)
showed very little formation of die drool during the extrusion of the tubes obtained
from compositions 1 to 4, 7, and 8 (which comprise BBSA), and no die drool for the
extrusion of the tubes obtained from compositions 5, 6, and 9 to 12 (which comprise
HP-BSA).
The selection of HP-BSA also allows improvement in the rheological
properties of the compositions of the invention for conversion by extrusion.
It is observed, moreover, that all of the bars have a flexural modulus of
less than 800 MPa, which characterizes high flexibility of the material.
More particularly, compositions 4 to 12 in accordance with the invention
give materials which exhibit in combination:
- flexural mod~~luvsa lues of less than 600 MPA, therefore manifesting
very great flexibility on the part of these materials,
- Charpy impact and VW impact values at -40°C which are also very high,
manifesting very high low-temperature impact strength of these
materials,
70
- thermooxidative aging values of more than 850 hours, manifesting
excellent aging resistance on the part of these materials.
Composition 3, which contains only 32% by weight of crosslinked
polyolefin, relative to the total weight of the composition, does not perform as well as
the compositions of the invention in terms of low-temperature impact strength (20%
breakage in the VW impact test and 6 kJlm2 in Charpy impact, at -40°C).
A comparison of examples 5 and 6 demonstrates the fact that an only
slightly greater proportion of plasticizer, which, admittedly, allows a reduction in the
flexural modulus of the corresponding materials, has a not insignificant effect on the
low-temperature impact strength properties: the percentage breakage in the VW
79
9
66
8
82
10
86
8
72
6
86
9.5
88
7.5
78
7
76
9
81
12
82
12
impact test at -40°C, accordingly, goes from 3 to 13, and the Charpy impact at -40°C
goes from 9 to 7.5 kJ/mZ.
The presence of PA11 in the compositions of the invention also allows
improvement of the flexibility and low-temperature impact strength properties of
5 materials obtained from said compositions (see compositions 4 and 8 on the one
hand and compositions 5 and 12 on the other).
The component formed wholly or partly from the composition of the
invention may more particularly be used for storing or conveying a fluid, said fluid
being a refrigerant or refrigerating fluid such as CO, or a fluorocarbon fluid such as
10 1,1,1,2-tetrafluoroethane or 2,3,3,3-tetrafluoropropene. More particularly, it may be
used in an air conditioning circuit, especially an automobile or truck air conditioning
circuit, or else a stationary air conditioning circuit.
1. A composition comprising - the weight percentages being given relative to
5 the total weight of the composition -:
- from 33 to 40%, advantageously from 35 to 37%, by weight of at least one
crosslinked polyolefin, the crosslinked polyolefin being obtained from:
at least one product (A) comprising an unsaturated epoxide, and
at least one product (8) comprising an unsaturated carboxylic anhydride,
- from 3 to lo%, advantageously from 4 to 8%, by weight of at least one
plasticizer,
- the rest being made up of at least one semiaromatic polyamide,
the weight amounts of (A) and (B), written respectively as [A] and [B], being such
that the ratio [B]I[A] is between 3 and 14, advantageously between 4 and 9.
15 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], being
such that [C]5[A] and the ratio [B]/([A]+[C]) being between 1.5 and 8,
20 advantageously between 2 and 7.
3. The composition as claimed in claim 1 or 2, characterized in that the product
(A) is a copolymer of ethylene, a saturated carboxylic acid vinyl ester, and an
unsaturated epoxide, or a copolymer of ethylene, an alkyl (meth)acrylate, and an
unsaturated epoxide.
25 4. The composition as claimed in any one of claims 1 to 3, 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
(meth)acrylate, and an unsaturated carboxylic anhydride.
5. The composition as claimed in any one of claims 2 to 4, characterized in that
30 the product (C) is a copolymer of ethylene and (meth)acrylic acid, or a copolymer of
ethylene, an alkyl (meth)acrylate, and (meth)acrylic acid.
6. The composition as claimed in any one of claims I to 5, 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.
7. The composition as claimed in claim6, characterized in that the
5 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 difonctional
acid), where a represents the number of carbon atoms in the diamine and b
represents the number of carbon atoms in the difunctional acid.
10 8. The composition as claimed in claim7, characterized in that the
semiaromatic polyamide comprises more than 50 mol% of first repeating unit(s),
advantageously more than 60 mol%.
9. The composition as clain~edin any one of claims 1 to 8, characterized in that
the plasticizer is selected from n-butylbenzenesulfonamide (BBSA) and
15 N-(2-hydroxypropyl)benzenesulfonamide (HP-BSA), and is preferably
N-(2-hydroxypropyl)benzenesulfonamide (HP-BSA).
10. The composition as claimed in any one of claims 1 to 9, characterized in that
it comprises at least one additive selected from processing aids, fillers, stabilizers,
dyes, mold release agents, flame retardants, surfactants, optical brighteners,
20 antioxidants, and mixtures thereof.
11. The composition as claimed in any one of claims 1 to 10, 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
polyesteramide, a polyphenylene sulfide, a polyphenylene oxide, a noncrosslinked
25 polyolefin, a fluoropolymer, and mixtures thereof.
12. 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), the plasticizer(s), the products (A), (B), and optionally
(C) for obtaining the crosslinked polyolefin(s).
13. The use of the composition as defined in any one of claims 1 to 11 for
making a single-layer structure or at least one layer of a multilayer structure.
14. A compon.ent, more particularly an extruded, coextruded or extrusion-blow
molded component, formed entirely or partly from the composition as defined in any ,
5 one of claims 1 to 11.
15. The use of the component as claimed in claim 14 for storing or conveying a
fluid, said fluid being selected from a fuel, a refrigerant or refrigerating fluid, a
cooling liquid, a brake fluid, an oil, a lubricant, a hydraulic fluid, a liquid based on
urea solution, a gas or gaseous emanations, a chemical product, and water.
10 16. The use of the component as claimed in claim 14 for storing or conveying a
fluid, said fluid being a refrigerant or refrigerating fluid such as CO, or a fluorocarbon
fluid such as I,,?1,2- tetrafluoroethane or 2,3,3,3-tetrafluoropropene.
17. The use as claimed in claim 15 in an air intake device or engine gas
ventilation device, in a braking assistance device, in an oil cooling device, in a
15 hydraulic device, in a braking device, in an engine cooling device, in a selective
catalytic reduction device, in an air conditioning circuit, or in a device for storage,
transport, or transfer of fuels.
-
18. The use as claimed in claim 17 in a stationary, automobile, or truck air
conditioning circuit.