wo 2009/138692 1 PCT/FR2009/050788
Method for increasing the difference between the
melting temperature and the crystallization temperature
of a polyamide powder
5 Description
Field of the invention
The present invention relates to polyarnides, such as
10 copolyarnides and copolyesterarnides, which have an
increased difference between their melting temperature
and their crystallization temperature
present invention also relates to
manufacturing powders of such
(Tf Tc). The
a process for
copolyarnides or
15 copolyesterarnides, irrespective of the type of
polymerization used during the process: hydrolytic
polycondensation, anionic or cationic polymerization.
A large difference between the Tf and the Tc of a
20 polyamide-based powder is particularly useful in many
uses, and especially in powder aggregation technology
by radiation-mediated melting or sintering, for
instance using a laser beam (laser sintering), infrared
radiation or UV radiation or any source of
25 electromagnetic radiation that makes it possible to
melt the powder in order to manufacture articles.
Prior art
30 The technology of aggregation of polyamide powders via
a laser beam serves to manufacture three-dimensional
articles such as prototypes and models, especially in
the motor vehicle, nautical, aeronautics, aerospace,
medical (prostheses, auditive systems, .cell tissues,
35 etc.), textile, clothing, fashion, decorative,
electronic casing, telephony, horne automation,
wo 2009/138692 2 PCT/FR2009/050788
information technology and lighting sectors.
A thin layer of polyamide powder is deposited on a
horizontal plate maintained in a chamber heated to a
5 temperature between the crystallization temperature Tc
and the melting temperature Tf of the polyamide powder.
The laser aggregates the powder particles at different
points in the powder layer according to a geometry
corresponding to the article, for example with the aid
10 of a computer which has in its memory the shape of the
article and which resti tutes this article in the form
of slices. Next, the horizontal plate is lowered by a
value corresponding to the thickness of the powder
layer (for example between 0.05 and 2 mm and generally
15 about 0.1 mm), then a new powder layer is deposited and
the laser aggregates powder particles according to a
geometry corresponding to this new slice of the
article, and so on. The procedure is repeated until the
entire article has been manufactured. An article
20 surrounded by powder is obtained inside the chamber.
The parts that have not been aggregated thus remain in
powder form. Next, the assembly is cooled gently and
the article solidifies as soon as its temperature falls
below the crystallization temperature Tc. After
25 complete cooling, the article is separated from the
powder, which may be reused for another operation.
Immediately after the action of the laser beam, the
temperature of the sample is higher than the
30 crystallization temperature (Tc) of the powder.
However, it arises that the introduction of a new layer
of colder powder causes the temperature of the part to
drop rapidly, which, when it passes below said Tc,
results in deformations (phenomenon known as curling).
35 Similarly, when the temperature of the powder in the
machine comes too close to the melting temperature (Tf)
wo 2009/138692 3 PCT/FR2009/050788
of the powder, this results in setting to a solid
around the parts (phenomenon known as caking), which is
manifested by the presence of lumps or clumps of powder
at certain regions on the surface of the article,
5 instead of having a good definition of the final
article.
To avoid these phenomena, it is therefore important to
keep the Tc as far away as possible from the Tf of the
10 powder. The difference Tf - Tc of the powder determines
the working-temperature window of the device that
serves to aggregate the powder particles via radiationmediated
melting. This working window is defined by its
upper temperature limit and its lower temperature
15 limit. The upper limit of the working window
corresponds to the temperature at which aggregation or
caking takes place. The lower limit of the working
window corresponds to the temperature at which
distortion or deformation or "curling" takes place.
20 This working window of the device is generally
estimated as about 10°C by a person skilled in the art
for use of the powder in the machine under good
conditions, i.e. without appearance of the phenomena
described above, which are the cause of defects on the
25 parts obtained.
Moreover, the highest possible heat of fusion (~Hf) is
required in order to obtain a good geometrical
definition of the manufactured parts. Specifically, if
30 this heat of fusion is too low, the energy provided by
the laser is sufficient to sinter by heat conduction
the powder particles close to the walls under
construction, and thus the geometrical precision of the
part is no longer satisfactori.
35
It is clear that everything that has just been
wo 2009/138692
explained
powders by
regarding the
laser beam is
radiation
4 PCT/FR2009/050788
aggregation of polyamide
valid irrespective of the
electromagnetic that causes the melting,
whether the melting process is selective or
5 unselective.
Patent US 6 245 281 (EP 0 911 142) describes the use,
for selective laser sintering, of polyamide 12 ( PA 12)
powders with an increased melting point and heat of
10 fusion. Their Tf is within the range from 185 to 189°C,
their Tc is within the range from 138 to 143°C (and so
42°C < Tf-Tc < 51 °C) and their .0.Hf is 112 ± 17 J/g.
These powders are obtained by precipitation of a
polyamide 12 prepared via ring opening and then
15 polycondensation of lauryllactam, according to the
process described in patent DE 2906647 (= US 4 334
056). This process requires several steps, in which PA
12 is first manufactured by condensation and is then
dissolved in ethanol between 130 and 150°C, and the
20 ethanol solution is cooled slowly to below 125 °C with
stirring, to make the PA 12 precipitate in powder form.
One drawback of the powders obtained via this process
is the evolution of gas during the process of sintering
residual monomers present in these powders, · in
25 particular when the manufacturing chamber is maintained
at a temperature just below the melting temperature of
the polymer. These gaseous monomers, after sublimation,
become deposited on the components of the machine,
which damages it. In particular, the condensation of
30 these monomers on optical surfaces impairs the
manufacturing conditions and leads to reduced
performance
complicated
preparation
and precision. To reduce this problem, a
intermediate step may be added during the
of the polyamide powder. This additional
35 step consists in extracting the residual monomers from
the· polyamide in hot alcohol, and necessitates an
wo 2009/138692 5 PCT/FR2009/050788
expensive manipulation.
Patent FR 2 8 67 190 describes a process for
manufacturing a polyamide 12 powder with a high Tf (the
5 Tc remaining unchanged) via a synthetic process of
anionic type starting with lauryllactam dissolved in a
sol vent in the presence of a filler and an amide of
10
formula R1-NH-CO-R2. The process of said document
consists in placing the solvent in lactam
supersaturation state,
Tc of the lactam in
i.e. at a temperature below the
the solvent. The polyamide 12
powders obtained via this process contain
residual monomers, have a melting point ·of
very few
at least
180°C and preferably within the temperature range from
15 182 °C to 184 °C, and a crystallization temperature of
about 135 ± 1 °C. This process involves very precise
control and monitoring of the temperature under
industrial conditions.
20
25
30
Patent FR 2
the melting
polyamide,
temperature
matter of
polyamides,
treatment.
873 380 describes a process for increasing
temperature and the heat of fusion of a
without modifying the crystallization
of the powder. In this process, it is a
increasing the Tf of pre-manufactured
for example of PA 11,
Polyamide in divided form
via a water
(granules or
powder) is placed in contact in the solid state with
water or water vapor at a
crystallization temperature
from the water and dried.
temperature close to its
Tc, and is then separated
This process thus involves
several steps subsequent to the manufacture of the
polyamide itself, the drying step being a limiting step
of the process.
35 French patent application 06/56029 relates to a process
for manufacturing a seeded powder ·particle formed from
wo 2009/138692 6 PCT/FR2009/050788
a polyamide shell and a polyamide core. The process
uses the anionic polymerization of lauryllactam or
caprolactam monomer or a blend thereof dissolved in a
solvent in the presence of seeds that are polyamide
5 powder particles. This characteristic core/shell
structure of the seeded polyamide powder leads to a
much lower Tc, the Tf being unchanged. The powders
obtained have a difference Tf Tc absolute value
higher than that of the powders of the prior art.
10 However, the difference obtained between Tf and Tc is
not as great as with the process of the abovementioned
patent FR 2 867 190.
One aim of the present invention is thus to provide a
15 process for efficiently increasing the difference Tf
Tc of existing polyamides.
In particular, one aim of the present invention is to
provide a process for manufacturing polyamide,
2 0 especially in the form of powder or granules, with an
enlarged difference Tf Tc, which is simple, quick
(comprising the fewest possible steps) and easy to
perform and which entrains few or no residual monomers
liable to affect the functioning of the machines used
25 for the manufacture of articles by powder aggregation.
The prior art discloses various means for adapting the
powders used in order to improve the aggregation
processes, especially in documents WO 2005/085 326, WO
30 2005/082 979 and WO 2005/082 973. However, these powder
adaptations generally have the drawback of considerably
modifying the mechanical properties of the powders and
thus those of the final 3D article. For example,
document WO 2005/082 979 relates to the use of p~wders
35 comprising a copolymer, copolyester and/or copolyamide
(Vestamel t®) in the manufacture of articles according
wo 2009/138692 7 PCT/FR2009/050788
to a selective process (laser) of layer-by-layer powder
aggregation. The examples of copolymers are especially
PA 12/6/6. 12 (in a mass percentage ratio of 40/30/30)
and PA 12/6/6.6 (in a mass percentage ratio of 33/33/33
5 or of 60/25/15). The use of these copolymer powders is
directed toward implementing the aggregation process at
lower temperatures than with. conventional powders. The
materials obtained with the copolymer powders described
are soft and do not have a sufficient modulus or
10 sufficient resistance to the working temperatures, for
example at room temperature, or at the heating
temperature of an engine in the aeronautical or motor
vehicle field, or alternatively in the information
technology field (heat given off by batteries).
15
One aim of the present invention is thus to increase
the difference between the Tf and the Tc of polyamide
powders while at the same time conserving their
mechanical properties, in order for the final article
20 obtained by aggregation of these powders to have
properties that are compatible with its use. In
particular, the material of the final article should
have sufficient strength and flexibility, in particular
with an elastic modulus of greater than 1500 N/mm2 and
25 an elongation at break of greater than 15% and
preferably greater than 20%.
The Applicant Company has now found a process for
manufacturing polyamides that are designed to satisfy
30 these various requirements. The process according to
the invention is a process for increasing the
difference Tf-Tc of polyamides, which is simple, quick
(in one step) and which produces few residual monomers.
The process of the invention concerns the mechanical
35 properties (breaking modulus and elongation at break)
of the usual polyamides in the powders obtained, and
5
wo 2009/138692 8 PCT/FR2009/050788
likewise in 3D articles, such as those obtained via the
techniques of aggregation by electromagnetic radiationmediated
melting of these powders.
Summary of the invention
One subject of the present invention is thus the use of
at least one minor comonomer in a process for
polymerizing at least one major monomer in order to
reduce the crystallization temperature and the melting
10 temperature of a polyamide derived from the
polymerization of said at least one major monomer, and
in order for the decrease in crystallization
temperature to be greater than the decrease in melting
temperature, respectively, relative to the
15 crystallization temperature and the melting temperature
of the polyamide resulting from the polymerization of
said at least one major monomer, said melting and
crystallization temperatures being measured by DSC
according to standard ISO 11357-3, said at least one
20 minor comonomer being polymerized according to the same
polymerization process as said at least one major
monomer, and said at least one minor comonomer being
chosen from aminocarboxylic acids, diamine-diacid
couples, lactams and/or lactones, and said at least one
25 minor comonomer representing from 0.1% to 20% by mass
of the total blend of said monomer(s) and comonomer(s),
preferably from 0.5% to 15% by mass of said total
blend, and preferably from 1% to 10% by mass of said
total blend.
30
Advantageously, the polymerization between the various
minor and major monomers is an anionic polymerization.
Advantageously, the polymerization between the various
35 minor and major monomers is a hydrolytic
polycondensation.
5
wo 2009/138692 9 PCT/FR2009/050788
Advantageously, said at least one major monomer
comprises 11-aminoundecanoic acid and/or lactam 12
and/or the decanediamine-sebacic acid couple (10/10).
Advantageously, said at least one minor comonomer is
chosen from aminocarboxylic acids, preferably a,waminocarboxylic
acids, comprising from 4 to 18 carbon
atoms, diamine-diacid couples comprising from 4 to 18
10 carbon atoms, lactams comprising from 3 to 18 carbon
atoms, lactones comprising from 3 to 18 carbon atoms,
and mixtures thereof.
Advantageously, said at least one minor comonomer
15 comprises 11-aminoundecanoic acid, 11-nheptylaminoundecanoic
acid, lauryllactam, caprolactam
and/or caprolactone.
Advantageously, said at least one minor comonomer
20 comprises at least one of the following diamine-diacid
couples: 6.6, 6.10, 6.11, 6.12, 6.14, 6.18, 10.10,
10.12, 10.14, 10.18, 10.T, T being terephthalic acid.
A subject of the present invention is also a process
25 for reducing the crystallization temperature and the
melting temperature of a polyamide (homopolyamide or
copolyamide) derived from the polymerization of at
least one major monomer, in which the reduction of the
crystallization temperature is greater than the
30 reduction of the melting temperature, said process
comprising a step of polymerizing said at least one
major monomer with at least one different minor
comonomer polymerized according to the same polymerization
process as said at least one major monomer,
35 said at least one minor comonomer being chosen from
aminocarboxylic acids, diamine-diacid couples, lactams
wo 2009/138692 10 PCT/FR2009/050788
and/or lactones, and said at least one minor comonomer
representing from 0.1% to 20% by mass of the total
blend of said monomer ( s) and comonomer ( s) , preferably
from 0.5% to 15% by mass of said total blend and
5 preferably from 1% to 10% by mass of said total blend.
Even more preferably, said at least one minor comonomer
represents from 1% to 7% by mass of the total blend of
said monomer(s) and comonomer(s), preferably from 1% to
10 5% by mass of said total blend, and said at least one
minor comonomer comprises 11-aminoundecanoic acid
and/or lauryllactam and/or caprolactam and/or
caprolactone and/or at least one of the following
diamine-diacid couples: 6.6, 6.10, 6.11, 6.12, 6.14,
15 6.18, 10.10, 10.12, 10.14, 10.18 and/or lO.T, T being
terephthalic acid.
According to one embodiment of the process of the
invention, the polymerization between the various minor
20 and major monomers is an anionic polymerization.
According to another embodiment of the process of the
invention, the polymerization between the various minor
and major monomers is a hydrolytic polycondensation.
25 Advantageously, said at least one major monomer
comprises 11-aminoundecanoic acid and/or lactam 12
and/or the decanediamine-sebacic acid couple (10.10).
Advantageously, said process also comprises, after said
30 polymerization step, at least one step chosen from:
dissolution, precipitation, extrusion, atomization,
spraying, cold nebulization, hot nebulization, milling,
cryogenic milling, screening, viscosity raising, and
combinations thereof.
35
A subject of the present invention · is also a
wo 2009/138692 11 PCT/FR2009/050788
copolyamide or copolyesteramide powder, which may be
manufactured according to the process defined
previously, said powder being derived from the
polymerization of at least two different monomers
5 polymerized according to the same polymerization
process, at least one of the comonomers being minor and
chosen from aminocarboxylic acids, diamine-diacid
couples, lactams and/or lactones, and said at least one
minor comonomer representing from 0.1% to 20% by mass
10 of the total blend of said monomer(s) and comonomer(s),
preferably from 0.5% to 15% by mass of said total
blend, and preferably from 1% to 10% by mass of said
total blend. Even more preferably, said at least one
minor comonomer represents from 1% to 7% by mass of the
15 total blend of said monomer ( s) and comonomer ( s),
preferably from 1% to 5% by mass of said total blend,
and said at least one minor comonomer comprises 11-
aminoundecanoic acid and/or lauryllactam and/or
caprolactam and/or caprolactone and/or at least one of
2 0 the following diamine-diacid couples: 6. 6, 6. 10, 6. 11,
6.12, 6.14, 6.18, 10.10, 10.12, 10.14, 10.18 and/or
10.T, T being terephthalic acid.
According to one embodiment, the powder of the
25 invention comprises an 11-aminoundecanoic acid major
monomer and at least one minor monomer chosen from the
hexamethylenediamine-adipic
lauryllactam, caprolactam
acid
and/or
couple ( 6. 6) '
caprolactone.
According to another embodiment, the powder comprises a
30 lauryllactam major monomer and a minor monomer chosen
35
from caprolactam, caprolactone and/or the
hexamethylenediamine-adipic acid couple (6.6).
Preferably,
chosen from
the powder according to the
the following polyamides:
invention is
PA 11/6.6
·comprising from 1% to 7% of 11-aminoundecanoic acid, PA
wo 2009/138692 12 PCT/FR2009/050788
11/N-heptylamino acid comprising from 1% to 5% of Nheptylamino
acid, PA 12/11 comprising from 1% to 12%
and preferably from 2% to 5% of 11-aminoundecanoic
acid, and PA 12/6 comprising from 1% to 5% of lactam 6,
5 all the percentages being given as mass relative to the
total mass of the blend of monomer and comonomer of
each preferred PA.
A subject of the present invention is also the use of
10 the powder according to the invention as defined
previously, in coatings, such as
anticorrosion compositions,
cosmetics; paper additives;
technologies via electromagnetic
paints,
textile
powder
varnishes,
coatings,
aggregation
radiation-mediated
15 melting or sintering for the manufacture of articles;
electrophoresis gels, multilayer composite materials;
the packaging industry; the toy industry; the textile
20
industry; the motor vehicle
electronics industry.
industry and/ or the
A subject of the present invention is also a process
for manufacturing polyamide articles by powder aggregation
via electromagnetic radiation -media ted melting,
the pblyamide powder having been obtained beforehand
25 according to the process defined previously or being in
accordance with the powder defined previously.
A subject of the present invention is also a
manufactured article obtained by electromagnetic
30 radiation-mediated melting of a powder according to the
invention.
Detailed description
35 The process of the invention makes it possible
simultaneously to reduce · the crystallization
wo 2009/138692 13 PCT/FR2009/050788
temperature and the melting temperature of polyamides.
However, the process of the invention substantially
reduces the crystallization temperature of polyamides,
whereas the melting temperature remains virtually
5 unchanged. This results in polyamides for which the
difference Tf Tc is greater as an absolute value
compared with the usual polyamides not manufactured
according to the process of the invention.
10 For the purposes of the invention, the term "polyamide"
means products of condensation of lactams, amino acids or
diacids with diamines and, as a general rule, any polymer
formed by units connected together via amide groups.
15 The process of the invention involves polymerizing at
least two different monomers, known as "comonomers",
i.e. at least one monomer and at least one comonomer
(monomer different than the first monomer) to form a
copolymer such as a copolyamide, abbreviated as CoPA,
20 or a copolyesteramide, abbreviated as CoPEA, as defined
hereinbelow.
25
In the
should
unit".
description that
be understood in
The case in which
follows, the term
the sense· of a
a repeating unit
"monomer"
"repeating
is formed
from the combination of a diacid with a diamine is
particular. It is considered that it is the combination
of a diamine and a diacid, i.e. the diamine-diacid
couple (in equimolar amount) that corresponds to the
30 monomer. This may be explained by the fact that,
individually, the diacid or the diamine is only a
structural unit, which is insufficient in itself to
form a polymer.
35 The process of the invention comprises the
polymerization of at least one major monomer, i.e. a
wo 2009/138692 14 PCT/FR2009/050788
monomer representing at least 80% by mass of the total
mass of the monomer blend, and at least one minor
comonomer, representing not more than 20% by mass of
the total mass of the total blend of said monomer ( s)
5 and comonomer(s).
The polymerization of the major monomer(s) may be
performed using one or more amide monomers individually
comprising from 4 to 30 carbon atoms and preferably
10 from 8 to 28 carbon atoms.
15
According to the invention, said at least one minor
comonomer represents from 0.1% to 20% by mass of said
total blend of said monomer(s) and comonomer(s),
preferably from 0.5% to 15% by mass of said total
blend, preferably from 1% to 10% by mass of said total
blend. Even more preferably, said at least one minor
comonomer represents from 1% to 7% by mass of the total
blend of said monomer ( s) and comonomer ( s) , preferably
20 from 1% to 5% by mass of said total blend.
According to a first embodiment, the process for
increasing the difference Tf-Tc of polyamide-based
powders (homopolyamide or copolyamide) comprises the
25 manufacture of CoPA powders from:
30
- at least one major monomer, corresponding to the
constituent monomer(s) of the base polyamide whose
difference Tf-Tc it is desired to increase, and
- and at least one different minor comonomer.
The term "copolyamide" (abbreviated as CoPA) means
products of polymerization of at least two different
monomers chosen from:
- monomers of amino acid or aminocarboxylic acid
35 type, and preferably a,w-aminocarboxylic acids;
- monomers of lactam type containing from 3 to 18
wo 2009/138692 15 PCT/FR2009/050788
~
carbon atoms on the main ring, and which may be
substituted;
- monomers of "diamine-diacid" type derived from the
reaction between an aliphatic diamine containing
5 between 4 and 18 carbon atoms and a dicarboxylic
10
acid containing between 4 and 18 carbon atoms; and
- mixtures thereof, with monomers having a different
number of carbons in the case of blends between a
monomer of amino acid type and a monomer of lactam
type.
Monomers of amino acid type:
Examples of ~,w-amino acids that may be mentioned
15 include those containing from 4 to 18 carbon atoms,
such as aminocaproic acid, 7-aminoheptanoic acid, 11-
aminoundecanoic acid, 11-n-heptylaminoundecanoic acid
and 12-aminododecanoic acid.
20 Monomers of lactam type:
Examples of lactams that may be mentioned include those
containing from 3 to 18 carbon atoms on the main ring
and which may be substituted. Examples that may be
25 mentioned include ~~~-dimethylpropiolactam, ~~~-
30
dimethylpropiolactam, amylolactam, caprolactam, also
known as lactam 6, capryllactam, also known as lactam
8, oenantholactam, 2-pyrrolidone and lauryllactam, also
known as a lactam 12.
Monomers of "diamine-diacid" type:
Examples of dicarboxylic acids that may be mentioned
include acids containing between 4· and 18 carbon atoms.
35 Examples that may be mentioned include adipic acid,
sebacic acid, azelaic acid, suberic acid, isophthalic
wo 2009/138692 16 PCT/FR2009/050788
acid, butanedioic acid, 1,4-cyclohexanedicarboxylic
acid, terephtha1ic acid, the sodium or lithium salt of
sulfoisophthalic acid, dimerized fatty acids (these
dimerized fatty acids have a dimer content of at least
5 98% and are preferably hydrogenated) and dodecanedioic
acid HOOC- ( CH2 ) 10-COOH.
Examples of diamines that may be mentioned include
aliphatic diamines containing from 4 to 18 atoms, which
10 may be aryl and/or saturated cyclic diamines. Examples
that may be mentioned include hexamethylenediamine,
piperazine, tetramethylenediamine, octamethylenediamine,
decamethylenediamine, dodecamethylenediamine,
1,5-diaminohexane, 2,2,4-trimethyl-1,6-diaminohexane,
15 diamine polyols, isophorone diamine (IPD), methylpentamethylenediamine
(MPDM), bis(aminocyclohexyl)methane
(BACM), bis(3-methyl-4-aminocyclohexyl)methane (BMACM),
meta-xylylenediamine, bis(p-aminocyclohexyl)methane and
trimethylhexamethylenediamine.
20
Examples of monomers of "diamine-diacid" type that may
be mentioned include those resulting from the
condensation of hexamethylenediamine with a C6 to C36
diacid, especially the monomers: 6.6, 6.10, 6.11, 6.12,
25 6.14, 6.18. Mention may be made of monomers resulting
from the condensation of decanediamine with a C6 to C36
diacid, especially the monomers: 10. 10, 10. 12, 10.14,
10.18; or resulting from the condensation of decanediamine
with a terephthalic acid, i.e. the monomer 10.T.
30
As examples of copolyamides formed from the various
types of-monomers described above, mention may be made
of copolyamides resulting from the condensation of at
least two a,w-aminocarboxylic acids or from two lactams
35 or from one lactam and one a, w-aminocarboxylic acid.
Mention ·may also be made of copolyamides resulting from
wo 2009/138692 17 PCT/FR2009/050788
the condensation of at least one a,w-aminocarboxylic
acid (or a lactam), at least one diamine and at least
one dicarboxylic acid. Mention may also be made of
copolyamides resulting from the condensation of an
5 aliphatic diamine with an aliphatic dicarboxylic acid
and at least one other monomer chosen from aliphatic
diamines different than the preceding one and aliphatic
diacids different than the preceding one.
10 Examples of copolyamides that may be mentioned include
copolymers of caprolactam and of lauryllactam (PA
6/12), copolymers of caprolactam, of hexamethylenediamine
and of adipic acid (PA 6/6.6), copolymers of
caprolactam, of lauryllactam, of hexamethylenediamine
15 and of adipic acid (PA 6/12/6. 6), copolymers of
caprolactam, of hexamethylenediamine and of azelaic
acid, of 11-aminoundecanoic acid, and of lauryllactam
(PA 6/6. 9/11/12), copolymers of caprolactam, of adipic
acid and of hexamethylenediamine, of 11-aminoundecanoic
20 acid, of lauryllactam ( PA 6/6. 6/11/12) , copolymers of
hexamethylenediamine, of azelaic acid and of
lauryllactam ( PA 6. 9/12), copolymers of 2-pyrrolidone
and of caprolactam ( PA 4 I 6) , copolymers of 2-
pyrrolidone and of lauryllactam ( PA 4/12) , copolymers
25 of caprolactam and of 11-aminoundecanoic acid (PA
6/11), copolymers of lauryllactam and of capryllactam
(PA 12/8), copolymers of 11-aminoundecanoic acid and of
2-pyrrolidone (PA 11/4), copolymers of capryllactam and
of caprolactam (PA 8/6), copolymers of capryllactam and
30 of 2-pyrrolidone ( PA 8 I 4) , copolymers of lauryllactam
and of capryllactam (PA 12/8), copolymers of
lauryllactam and of 11-aminoundecanoic acid (PA 12/11).
Advantageously, said at least one major monomer and/or
35 said at least one minor comonomer used in the process
of the invention comprise(s) 11-aminoundecanoic acid or
wo 2009/138692 18 PCT/FR2009/050788
lactam 12.
According to a second embodiment of the invention, the
process for increasing the difference Tf-Tc of
5 polyamide-based powders includes the manufacture of
copolyesteramide (CoPEA) powders, by polymerization of
at least one major monomer, corresponding to the
constituent monomer(s) of the base polyamide whose
difference Tf-Tc it is desired to increase, and of at
10 least one minor comonomer, comprising a lactone.
15
The process for preparing these copolyesteramide
powders via anionic polymerization is described in
document EP 1 172 396.
The major monomers that may be used to manufacture the
copolyesteramides are the same as those described
above. At least one lactam, preferably chosen from
caprolactam and lauryllactam, is advantageously used.
20 Examples of lactones that may be mentioned include
caprolactone, valerolactone and butyrolactone.
Caprolactone and/or butyrolactone is preferably used.
As regards the copolyesteramides, said at · least one
25 major monomer and said at least one minor comonomer
comprising the lactone are advantageously used in the
following respective proportions of major-minor
monomers (mass%) ranging from: 80-20% to 99.5-0.5% (the
total being 100%).
30
According to a third embodiment, the process according
to the invention uses blends of copolyamide and/or of
copolyesteramide.
35 According to the process of the invention, the CoPAs or
the CoPEAs, and similarly the various monomers (minor
wo 2009/138692 19 PCT/FR2009/050788
and major) included in the composition of these CoPAs
or CoPEAs, in particular the possible monomers of
diamine-diacid type, are derived from the same
polymerization process, irrespective
5 hydrolytic polycondensation, anionic
cationic polymerization, etc.
of its type:
polymerization,
According to one embodiment of the process of the
invention, the polymerization between the various
10 monomers (minor and major) is of the hydrolytic
polycondensation type. Hydrolytic polymerization, used
above all for lactams, is induced by water at high
temperature. For example, the hydrolytic polymerization
of lactams consists in opening the lactam with water
15 and then in heating under pressure to polymerize.
Optionally, a catalyst such as phosphoric acid may also
be employed in the hydrolytic process.
As examples of CoPAs or CoPEAs derived from hydrolytic
20 polymerization, mention may be made of those comprising
an 11-aminoundecanoic acid major monomer and at least
one minor monomer chosen from the hexamethylenediamineadipic
acid couple (6.6), lauryllactam, caprolactam
and/or 11-n-heptylaminoundecanoic acid.
25
According to another embodiment of the process of the
invention, the polymerization between the various
monomers (minor and major) is of the anionic
polymerization type. Anionic polymerization is
30 performed at temperatures much lower than those used
for hydrolytic or cationic mechanisms. Anionic
polymerization is performed continuously or,
preferably, in batch mode in a sol vent. The anionic
route more ·specifically concerns cyclic molecules, such
35 as lactams and lactones. For example, the mechanism of
anionic polymerization of · lactams proceeds in three
wo 2009/138692 20 PCT/FR2009/050788
steps: an initiation step to form the lactamate anion,
then an activation reaction which leads to the
acyllactam and finally a propagation step. The anionic
polymerization method is thus based essentially on the
5 use of a catalyst and an activator
presence of a finely divided mineral
that serves as a crystallization
presence of an amide. The process
patents EP 192 515 and EP 303 530.
optionally in the
or organic filler
seed and in the
is described in
10
As regards the catalyst, mention may be made of sodium
or a compound thereof, such as sodium hydride or sodium
methoxide.
15 As regards the activator, mention may be made of
lactam-N-carboxyanilides, isocyanates, carbodiimides,
cyanimides, acyllactams, triazines, ureas, Nsubstituted
imides and esters, inter alia.
20 As regards the filler, mention may be made of PA
powder, for example Orgasol® powder, silica, talc, etc.
As regards the N, N' -alkylenebisamide, mention may be
made more particularly of N, N''-ethylenebisstearamide
25 (EBS), N,N'-ethylenebisoleamide, N,N'-ethylenebispalmitamide,
gadoleamide, cetoleamide and erucamide,
N,N'-dioleyldipamide and N,N'-dierucylamide, etc.
As examples of CoPAs or CoPEAs derived from anionic
30 polymerization, mention may be made of those comprising
a lauryllactam major monomer and a minor monomer chosen
from caprolactam, caprolactone and/or the
hexamethylenediamine-adipic acid couple (6.6).
35 The very narrow particle size distribution of the
powders advantageously obtained by anionic
wo 2009/138692 21 PCT/FR2009/050788
polymerization promotes their use for the manufacture
of parts via radiation-mediated aggregation (infrared,
UV curing, etc.) since it leads to a very fine
definition of the parts, and it reduces the problems of
5 formation of dusts during the use of the powder.
Furthermore, the molecular mass of the polymer does not
increase, even after long exposure to temperatures
close to and below the melting temperature of the
powder. This means that the powder can be recycled a
10 large number of times without modification of its
behavior during the manufacture of parts via radiationmediated
aggregation, the properties of said parts also
remaining constant during the process. In addition,
this process allows the manufacture via powder
15 aggregation of an article that has good mechanical
properties.
Needless to say, any other polymerization process may
also be envisioned provided that all the (co)monomers
20 used for manufacturing a CoP A or a Co PEA according to
the invention can be polymerized together in the same
polymerization process.
As an additional example, mention may be made of
25 cationic polymerization, catalyzed with acids under
anhydrous conditions. In this case, acids such as
hydrochloric acid, phosphoric acid or hydrobromic acid
are the most reactive, but the use of Lewis acids or
ammonium salts is also possible. There are essentially
30 two types of activation and of chain growth. Either the
activated monomer reacts with the neutral reactive
center, or it is the reactive center that is activated
and the monomer is neutral.
35 Depending on the mode of synthesis, CoPA or CoPEA
powder or CoPA or CoPEA granules are obtained directly.
wo 2009/138692 22 PCT/FR2009/050788
There are two production modes for obtaining CoPA or
CoPEA powder: directly or indirectly.
5 In the case of the direct route, mention may be made of
polymerization and precipitation (precipitating
polymerization) of the polymer in a solvent. Powder is
obtained directly during the polymerization. This is
generally the case in anionic polymerization.
10
In the case of the indirect route for obtaining powder,
examples that may be mentioned include dissolutionprecipitation,
i.e. solubilization of the CoPA or Co PEA
polymer in a hot solvent followed by precipitation of the
15 powder by slow cooling. Mention may also be made of
atomization, i.e. spraying of a solution of the cooled
polymer. This technique is also known as "cold
nebulization" or "spray cooling". There is also a process
of polymer extrusion, followed by atomization with a
20 heated high-pressure nozzle, and then cooling of the
powder obtained. This technique is also known as "hot
nebulization" or "spray drying". Mention may also be made
of the milling/screening of polymer granules, optionally
followed by raising the viscosity. The milling may be
25 cryogenic. All these powder production techniques are
already known to those skilled in the art.
For use in the aggregation technique via radiationmediated
melting, either powders or granules are used. The
30 granules are particles of any shape from a few mm to 1 em.
They are, for example, granules obtained at an extruder
outlet. Powders are preferentially used in the melting or
sintering aggregation process. These powders may be up to
350 J.1ffi in size and are advantageously between 10 and
35 100 J.1ffi in size. Preferably, the D50 is 60 J.1ffi (i.e. 50% of
the particles are less than 60 J.1ffi in size) .
5
wo 2009/138692 23 PCT/FR2009/050788
A subject
copolyamide
according to
powder being
of the present invention is also a
or copolyesteramide powder manufactured
the process described previously, said
derived from the polymerization of at
least two different monomers polymerized according to
the same polymerization process, at least one of the
comonomers being minor and chosen from aminocarboxylic
acids, diamine-diacid couples, lactams and/ or lactones
10 as described previously, and said at least one minor
comonomer representing 0.1% to 20% by mass of the total
monomer blend, preferably from 0.5% to 15% by mass of
the total monomer blend, preferably from 1% to 10% by
mass of the total monomer blend. Even more preferably,
15 said at least one minor comonomer represents from 1% to
7% by mass of the total blend of said monomer ( s) and
comonomer(s), preferably from 1% to 5% by mass of said
total blend and said at least one minor comonomer
comprises 11-aminoundecanoic acid and/or lauryllactam
20 and/or caprolactam and/ or caprolactone and/ or at least
one of the following diamine-diacid couples: 6.6, 6.10,
6.11, 6.12, 6.14, 6.18, 10.10, 10.12, 10.14, 10.18
and/or 10.T, T being terephthalic acid.
25 The powders according to the invention may also
comprise additives that contribute toward improving the
properties of the powder for its use in the aggregation
technique. Examples that may be mentioned include
pigments for coloration, Ti02 , fillers or pigments for
30 infrared absorption, carbon black, mineral fillers for
reducing the internal stresses, and flame-retardant
addi t·i ves. Additives for improving the mechanical
properties (ultimate stress and elongation at break) of
the parts obtained by melting may also be added. These
35 fillers are, for example, glass fibers, carbon fibers,
nanofillers, nanoclays and carbon nanotubes.
wo 2009/138692 24 PCT/FR2009/050788
Introducing these fillers at the time of synthesis
improves their dispersion and their efficacy.
The powders according to the invention may be
5 advantageously used in coatings, paints, anticorrosion
compositions, paper additives, powder aggregation
techniques via radiation-mediated melting or sintering
for the manufacture of articles, electrophoresis gels,
multilayer composite materials, the packaging industry,
10 the toy industry, the textile industry, the motor
vehicle industry and/or the electronics industry.
A subject of the present invention is also a process
for manufacturing polyamide articles by melt-induced
15 powder aggregation via radiation, the polyamide powder
having been obtained beforehand according to the
process mentioned above. Examples of radiation that may
be mentioned include that provided by a laser beam (the
process is then known as "laser sintering") . Mention
20 may also be made of the process in which a mask is
deposited between the layer of powder and the radiation
source, the powder particles protected from the
radiation by the mask not being aggregated.
25 A subject of the present invention is also a
manufactured 30 article obtained by melting of a powder
using electromagnetic radiation. This article may be
chosen from prototypes and models, especially in the
motor vehicle, nautical, aeronautics, aerospace,
30 medical (prostheses, auditive systems, cell tissues,
etc.), textile, clothing, fashion, decorative,
electronic casing, telephony, home automation,
information technology and lighting sectors.
35 Examples
wo 2009/138692 25 PCT/FR2009/050788
The examples that follow illustrate embodiments of the
present invention without, however, limiting it.
In all the examples that follow:
5 - the mean diameters (by volume) are determined from
the particle size distribution measured using a Coulter
LS230 granulometer, with version 2.11a of the software,
- the relative viscosities are measured at 20°C, as a
solution at 0.5% by mass in meta-cresol ("Ato method"),
10 - analysis of the powders or granules (measurement of
the thermal characteristics) is performed by DSC
according to standard ISO 11357-3 "Plastics
Differential Scanning Calorimetry (DSC) Part 3:
Determination of temperature and enthalpy of melting
15 and crystallization". The temperatures here that are
more particularly of interest to the invention are the
melting temperature during the first heating (Tf1) and
the crystallization temperature (Tc). Specifically, as
is known to those skilled in the art (in the field of
20 manufacture of 3D articles by melt-induced powder
aggregation) , the difference "Tf-Tc" corresponds to
Tf1-Tc.
In the examples that follow, the difference Tf-Tc or
25 the difference Tf1-Tc is thus indicated independently.
Example 1
The comparative products 1 and the products of Examples
30 1.1 to 1.3 are prepared according to the same procedure
in the following manner:
35
Comparative Example 1
2757 ml of solvent and
( lauryllactam) , 7. 2 g of
then 899 g of
EBS and 3. 94 g
lactam 12
of organic
wo 2009/138692 26 PCT/FR2009/050788
filler, namely polyamide 12 powder (PA 12: Orgasol®
2001 EXD NAT1) are successively introduced into a
reactor maintained under nitrogen. After starting the
stirring at 300 rpm, the mixture is heated gradually to
5 105°C, and 360 ml of solvent are then distilled off so
as to entrain azeotropically any trace of water that
may be present.
After returning to atmospheric pressure, the anionic
10 catalyst, 2.7 g of sodium hydride at a purity of 60% in
oil, is then added rapidly under nitrogen and the
stirring is increased to 550 rpm under nitrogen at
105°C for 30 minutes.
15 By means of a small metering pump, the chosen
activator, namely stearyl isocyanate (19.2 g made up to
220.5 g with solvent) is injected continuously into the
reaction medium according to the following program:
20
- 26 g/hour of isocyanate solution for 180 minutes
- 71.25 g/hour of isocyanate solution
120 minutes.
for
In parallel, the temperature is maintained at 105°C for
180 minutes during the injection, and is then raised to
25 130°C over 90 minutes and maintained at 130°C for a
further 150 minutes after the end of introduction of
the isocyanate.
Once the polymerization is complete, the reactor is
30 virtually clean. After cooling to 80 °C, separation by
settling and drying, the powder obtained is subjected
to DSC analysis.
The Dsc· analysis shows the values Tf
35 139.1°C.
183.7°C and Tc
WO 2009/138692 27 PCT/FR2009/050788
The powders of Examples 1 to 3 are manufactured
according to the same procedure as in the Comparative
Example 1. In these Examples 1 to 3 according to the
invention, a small amount of lactam 6 comonomer is used
5 in addition to the lactam 12.
Example 1.1
2757 ml of solvent and then 899 g of lactam 12, 18 g of
10 lactam 6, 7.2 g of EBS and 3.94 g of Orgasol® 2001 EXD
NAT1 (PA 12 powder) are successively introduced into
the reactor maintained under nitrogen.
The DSC analysis of the powder obtained shows that Tf
15 180.1°C and Tc = 135.3°C.
Example 1.2
2757 ml of solvent and then 899 g of lactam 12, 36 g of
20 lactam 6, 7.2 g of EBS and 3.94 g of Orgasol® 2001 EXD
NAT1 (PA 12 powder) are successively introduced into
the reactor maintained under nitrogen.
The DSC analysis of the powder obtained shows that Tf
25 179.3°C and Tc = 132.8°C.
Example 1.3
2757 ml of solvent and then 899 g of lactam 12, 45 g of
30 lactam 6, 7.2 g of EBS and 3.94 g of Orgasol® 2001 EXD
NAT1 (PA 12 powder) are successively introduced into
the reactor maintained under nitrogen.
The DSC analysis of the powder obtained shows that Tf
35 178.2°C and Tc = 128.4°C.
5
wo 2009/138692 28 PCT/FR2009/050788
The DSC analysis results for Comparative Example 1 and
Examples 1.1 to 1.3 are summarized in Table 1.
TABLE 1
Compara- Example Example Example
tive 1 1.1 1.2 1.3
Lactam 6 (g) 0 18 36 45
Lactam 12 (g) 899 899 899 899
MOnomer/comonomer
100/0 98/2 96/4 95/5
percentage: 12/6 (%)
EBS (g) 7.2 7.2 7.2 7.2
Organic filler (g)
3.94 3.94 3.94 3.94
(PA 12)
Stearyl isocyanate
19.2 19.2 19.2 19.2
(g)
NaH (g) 2. 7 2. 7 2.7 2.7
Melting tempera-
183.7 180.1 179.3 178.2
ture Tf1 ( o C)
Crystallization
139.1 135.3 132.8 128.4
temperature ( o C)
ITf-Tcl 44.6 44.8 46.5 4 9. 8
Relative viscosity
of the final 1. 32 1. 25 1.19 1. 25
powder
Mean diameter (pm) 46 60 85 297
The samples of Examples 1. 1 to 1. 3 according to the
invention, which contain a lauryllactam major monomer
(lactam 12) and a caprolactam minor monomer (lactam 6),
10 have a lower melting temperature and crystallization
temperature and a greater difference ITf-Tcl than
Comparative Example 1 (lactam 12 homopolyamide).
In a melt-induced powder aggregation machine, use of
wo 2009/138692 29 PCT/FR2009/050788
the copolyamides of Examples 1.1 to 1.3 makes it
possible more easily to optimize the machine settings.
Their greater difference ITf-Tcl affords a wider
working or transformation window (greater than 10°C).
5 This wide window affords a person skilled in the art
greater flexibility for adjusting the parameters
(especially the temperature) of the machine and thus
for avoiding "caking", on the one hand, and "curling",
on the other hand, of the manufactured parts.
10
The various powders according to the invention are each
introduced into a melt-induced powder aggregation
machine and are subjected to laser radiation. After
cooling the various specimens obtained,
15 evaluated visually by a panel of experts.
they are
Table 2 below shows the influence of the process of the
invention on the magnitude of the powder "caking" or
"setting" or "lumps" or "clumps" defects at the surface
20 of a 30 article obtained by laser sintering.
TABLE 2
Powders used for Lac·tam Caking
the laser sintering 6 ( %) problem
Compara- PA 12 0 Caking
tive 1
Examples Example 0 PA 12/6 1 Caking
according divided by 3
to the Example 1 PA 12/6 2 Very little
invention caking (divided
by 7)
Example 2 PA 12/6 4 No caking
Example 3 PA 12/6 5 No caking
wo 2009/138692 30 PCT/FR2009/050788
Furthermore, the parts thus obtained by laser sintering
with the powders of Examples 1.1 to 1.3 have mechanical
properties (especially the breaking modulus and the
elongation at break) comparable to those of the
5 Comparative Example 1.
Moreover, the anionic polymerization advantageously
used in the process of the invention makes it possible
to limit the amount of residual monomers in the final
10 powder, which are liable to condense on the parts of
the melt-induced powder aggregation machine. The
precision of the 3D articles thus remains optimal and
unchanged even after several manufacturing cycles.
15 Example 4
The graph of Figure 1 illustrates the impact of the
content of comonomer (in this case lactam 12 or monomer
6. 6) in a polyamide 11 ( PA 11) on the change in the
20 difference between Tf and Tc. The graph shows that it
is the comonomer 6.6 that most broadens the window (Tf
- Tc) for contents of between 5% and 20%.
25
Example 5
A CoPA 11/6.6 powder (7% of 6.6) is synthesized from
granules obtained from hydrolytic polymerization, which
are reduced to powder by cryogenic milling. The powder
obtained has a relative viscosity equal to 1 (20°C, as
30 a solution at 0.5% by mass in meta-cresol).
This powder is compared with:
- a PA 12 powder obtained anionically. The PA 12 powder
has a relative viscosity equal to 1.3 (20°C, as a
35 solution at 0.5% by mass in meta-cresol),
- a PA 11 powder ·synthesized by milling a prepolymer
wo 2009/138692 31 PCT/FR2009/050788
obtained by polycondensation of 11-aminoundecanoic
acid, followed by treatment with water and raising of
the viscosity. The PA 11 powder has a relative
viscosity equal to 1.35 (20°C, as a solution at 0.5% by
5 mass in meta-cresol).
10
The DSC analysis
characteristics of
of the three powders shows the
Tf1 (first heating), Tf2 (second
heating) and Tc collated in Table 3 below.
TABLE 3
CoPA 11/6.6
PA 12 PA 11
Example 4
Tf1 (first Tfl (first Tf1 (first
heating)/Tc/Tf2 heating)/Tc/Tf2 heating)/Tc/Tf2
(second heating) (second heating) (second heating)
delta Tf1-Tc delta Tf1-Tc delta Tf1-Tc
( OC) ( OC) ( OC)
178/129/170 185/140/178 203/156/189
49 45 47
The three powders are tested in a laser sintering
15 machine.
By virtue of its difference in Tf-Tc equal to 49°C, the
transformation window of the CoPA 11/6.6 powder in the
machine is 14 °C, which allows the SLS machine to be
20 used under good conditions.
Furthermore, very little or no caking is observed with
the CoPA 11/6.6 powder of the invention.
25 The mechanical properties of the parts manufactured by
laser sintering from CoPA 11/6.6 are compared with
those manufactured from PA 12 and PA 11 in Table 4
5
wo 2009/138692 32 PCT/FR2009/050788
below.
TABLE 4
Mechanical CoPA 11/6.6
Standards PA 12 PA 11
tests Example 4
Elongation
~ 0 22.3 29.7 45
ASTM at break
D 638:91-1 Tensile
MPa 1739 1786 1797
modulus
The parts manufactured from CoPA 11/6.6 have a modulus
of 1786 MPa, which is close to that of PA 12 and PA 11,
and an elongation at break in the range 25-30%. The
elongation at break of CoPA 11/6.6 is between that of
10 polyamide 12 and that of polyamide 11.
Example 6
The DSC values according to standard ISO 11357 are
15 compared (Table 5) between a PA 12 (Comparative) and a
polyamide 12 modified, respectively, with 6% and 12% by
weight of 11-aminoundecanoic acid (examples according
to the invention) .
20 TABLE 5
A to
DSC standard ISO 11357-3
method
Tf1-
1st 2nd
Relative Cooling Tc
Compositions heating heating
viscosity Tc ( OC)
Tfl ( OC) Tf2 ( OC)
PA 12 (Comparative) 1. 63 177 177.1 136.1 40.9
CoPA 12/11 (6%) (according
1. 69 175.2 174 133.2 42
to the invention)
wo 2009/138692 33 PCT/FR2009/050788
lauryllactam (94%) /11-
aminoundecanoic acid ( 6%)
CoPA 12/11 (12%) (according
to the invention)
1. 62 170.8 170.3 127.7 43.1
lauryllactam (88%) /11-
aminoundecanoic acid (12%)
A decrease of 3 to 8°C in the crystallization
temperature and an increase in the difference Tf1-Tc
are found for the two PA 12 modified according to the
5 process of the invention, compared with the
homopolyamide PA 12.
Example 7
10 The DSC values according to standard ISO 11357 are
compared (in Table 6) between a PA 11 (Comparative) and
a polyamide 11 modified, respectively, with 1% and 5%
by weight of N-heptylamino acid (examples according to
the invention) .
15
TABLE 6
Mn number- Relative DSC standard ISO 11357
average viscosity 1st 2nd Tf1-
Compositions Cooling
molecular (A to heating heating Tc
Tc
mass method) Tf1 Tf2
PA 11 (Compa- 23 000 P: 192 P: 189.7 P: 157.6
1. 45 34.4
rative) D: 47.3 D: 59.2 D: -55.6
PA 11 + 5% N- 20 000
hepty1amino acid P: 189 P: 188.1 P: 151.9
1. 32 37.1
(according to D: 52.1 D: 55.7 D: -51.8
the invention)
PA 11 + 1% N- 23 000 P: 192.7 P: 191.7 P: 152.6
1. 48 40.1
heptylamino acid D: 46.6 D: 51 D: -55.8
wo 2009/138692
I (according to
~he inventlon)
34 PCT/FR2009/050788
II
P: for Tf1, Tf2 and Tc, the measurement corresponds to
the peak "P" (°C)
D: corresponds to the enthalpy DH (J/g)
5 A decrease of 5 to 6°C in the crystallization
temperature is found for the two PA 11 modified
according to the process of the invention, compared
with the homopolyamide PA 11.
10 As regards the amount of minor comonomer used, it is
noted that the difference Tf1-Tc is greater with 1% of
N-heptylamino acid than with 5% of N-heptylamino acid.

0 .
L--.\, u I \1'-'1
.!.--.&-. A process for reducing the crystallization
temperature and the melting temperature of a polyamide
derived from the polymerization of at least one major
monomer, said process comprising a step of
polymerization of said at least one major lflOnomer with
at least one different minor comonorner polymerized
according to the same polymerization process as said at
least one major monomer, said at least one minor
comonomer comprising
lauryllactam and/or
and/or at least one
couples: 6.6, 6.10,
11-arninoundecanoic acid and/or
caprolactam and/or· caproJactone
of Lhe fo_l.lowing diamine-rli acid
6.11, 6.12, 6.14, 6.18, 10.10,
10.12, 10.14, 10.18 and/or lO.T, T being terephthalic
acid, said at least one minor comonomer representing
from 1% to 7% by mass of the total blend of said
monomer(s) and comonomer(s), preferably 1% to 5% by
mass of said total blend, such that the reduction in
the crystallization temperature is greater than the
reduction in the melting temperature, respectively(
relative to the crystallization temperature and the
melting temperature of the polyamide obtained from the
polymerization of said at least one major monomer, said
melting and crystallization temperatures being measured
by DSC according to standard ISO 11357-3.
The process as claimed in claim 8, in which the
polymerization between the various minor and major
monomers is an anionic polymerization.
The process as claimed in claim 8, in which the
polymerization between the various minor and major
monomers is a hydrolytic polycondensation.
'-1- y. The process as claimed in one of claims 8 to 10,
in which said at least one major monomer comprises 11-
aminoundecanoic acid and/or lactam 12 and/or the
decanediamine-sebacic acid couple (10.10).
5· ...:r:2". The process as claimed in any one of the preceding
claims, also comprising, after said polymerization
step, at least one step chosen from: dissolution,
precipitation, extrusion, atomization, spraying, cold
nebulization, hot nebulization, milling, cryogenic
milling, screening, viscosity raising, and combinations
thereof.
i~ . ..a-:'). A copolyamide or copolyesteramide powder, which
may be manufactured according to the process of any one
1 ,"_).
31-1-
of clAims 8 to 1?, .sc:1id powder beinq obt:airwd from the
polymerization of at
p o 1 ym e r i zed a c co .r ding
1ei15t two
to t:he
di ffc:rent monomr?r.s
polymerizution
process, at least one of the comonomers being minor And
compr i .sing 11-aminoundecanoic acid and/ or la uryllactam
and/or cap.rolactam and/or caprolactone and/or at least
one of the following diamine-diacid couples: 6.6, 6.10,
6.11, 6.1?, 6.14, 6.18, 10.10, 10.12, 10.14, 10.18
and/or 10.'1', T being terephthalic r-lcid, .sc:lid nt .lf:'rlst:
one minor comonomer representing rrom l'i, to ·r'o by md::>~:>
of the total blend of said monomer(s) and comonomer(s),
pref(c;cably l'b tu S~ by lllet~>.s uf :::.:u.i.d lt-'L,-ll l.JJe:rn:.l.
)...4-. The powder a.s claimed in cLaim 13, comprising l 111<<11<1111<·'1" ;-JII , . , ·, .. , .
ddditlvcs. powder