Note: Descriptions are shown in the official language in which they were submitted.
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- 1 - 8CU 4327
POLYET~ERIMIDE-POLYAMIDE BLENDS
Background of the Invention
Polyetherimide-polyamide blends have been
prepared to maintain the flexural and tensile properties
of the polyetherimide while lowering the overall cost
of the polymer. Such blends have also recently been
associated with lower molding temperatures and superior
chemical resistances when compared to the polyetherimide
component alone. (See European Patent Application 83109701.9,
publication no. 0 104 659).
Summary of'the Invention
In accordance with the present invention, a
polymer blend contains (a) a polyetherimide and (b) a
polyamide, wherein the polyetherimide comprises from 5%
to 39% of the blend by weight and wherein the polyetherimide
is represented by the formula hereinafter described. It
has been discovered that by incorporating a minor proportion
of polyetherimide into polyamides, the molding character-
istics of the polyamide can be significantly improved.
In particular, such blends have been found to exhibit
substantially less mold shrinkage than the polyamide
alone. Moreover, the blends are less susceptible to water
absorption then unmodified polyamides, which improves the
quality of molded articles.
Detailed Description of the Invention
_
The blends of the invention include a
polyetherimicle of the formula:
. . .
~Z~o~38
~ 2 - 8CU 4327
-- O O -
- N/ \ A - o _ Z _ o - A/ \ N - R -
\,C,/ \,C,/
O a
where a represents a whole number in excess of 1, e.g.,
10 to 10,000 or more, the group -O-A'' is selected from:
~-~ ,~~
R' being hydrogen, lower alkyl or lower alkoxy,
preferably the polyetherimide includes the latter
; -O-A~ group where R' is hydrogen such that the
polyetherimide is of the formula:
- O O - :,.
N ~ J - z - O ~ N -
O O a
and the divalent bonds of the -O-Z-O radical are in the
3,3 7; 3,4'; 4,3' or the 4,4' position; and Z is a member
of the class consisting Of tl) 3
:.
~Z8~X38
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H3C C~I3 H3C CH3
H3C CH3
H3C Br Br CH3 Br Br
~ ~ ~ <
~0~ ~:(CH3) 2
H3C Br Br CH3 Br Br
and (2) divalent organic radicals of the general formula:
~ (X)q~
where X is a member selected from the class consisting of
divalent radicals of the formulas,
O O
ll ll
y 2y ~ ,S" -O- and -S-
where q is 0 or 1, y is a whole number from 1 to 5,
and R is a divalent organic radical selected from the
class consisting of (1) aromatic hydrocarbon radicals
having from 6-20 carbon atoms and halogenated derivatives
thereof, (2) alkylene radicals and cycloalkylene radicals
having from 2-20 carbon atoms, C(2 8) alkylene terminated
polydiorganosiloxane, and (3) divalent radicals included
by the formula
~ Q ~
~.
.,
. .
~LZ~ 38
- 4 - 8CU 4327
where Q is a member selected from the class consisting of
O O
.. ..
-O-, -C-, -S-, -S- and -C H
O
where x is a whole number from 1 to 5 inclusive.
Particularly preferred polyetherimides for the purposes
of the present invention include those where -O-A and Z
; respectively are:
_ O ~ and ~ C
CH3
and R is selected from:
~ CH2~ ~> O <~
~
The polyetherimides where R is metaphenylene are most
preferred.
The blends of the invention also include a
polyamide. Polyamides are well known in the art and the
term embraces those semi-crystalline and amorphous resins
having a molecular weight of at least 5000 commonly referred
to as nylons. Polyamides generally have repeating
structural units represented by the general formula;
O H O O N H
- C-R2-N - - or - - C-R3-c-N-R4-N - n
wherein R2, R3 and R4, which may be the same or different,
,~, ,-
' -
~'
~280~3a
- 5 - 8CU 4327
each represents an alkylene group having from 4 to 11
carbon atoms, and n is an integer of 30 to 500 or more.
Suitable examples of alkylene groups containing 4 to 11
carbon atoms for R2, R3, and R4 include a tetramethylene
group, a pentamethylene group, a hexamethylene group, a
heptamethylene group, an octamethylene group, a nonamethylene
group, decamethylene group, an undecamethylene group, and
the like.
Specifically, the following polyamides may be
incorporated in the blends of the invention:
polyhexamethylene adipamide (nylon 6:6)
polypyrrolidone (nylon 4)
polycaprolactam (nylon 6)
polyheptolactam (nylon 7)
polycapryllactam (nylon 8)
polynonanolactam (nylon 9)
polyundecanolactam (nylon 11)
polydodecanolactam (nylon 12)
polyhexamethylene azelaiamide (nylon 6:9)
polyhexamethylene sebacamide (nylon 6:10)
polyhexamethylene isophthalamide (nylon 6:ip)
polymetaxylylene adipamide (nylon MXD:6)
polyamide of hexamethylenediamine and
n-dodecanedioic acid (nylon 6:12)
polyamide of dodecamethylenediamine and n-
dodecanedioic acid (nylon 12:12)
Nylon copolymers may also be used as the
polyamide component of the blends of this invention.
For example, suitable copolymers include the following:
hexamethylene adipamide/caprolactam (nylon 6:6/6)
hexamethylene adipamide/hexamethylene-
isophthalamide (nylon 6:6/6ip)
hexamethylene adipamide/hexamethylene-
terephthalamide (nylon 6:6/6T)
trimethylhexamethylene oxamide/hexamethylene
oxamide (nylon trimethyl-6:2/6:2)
.,
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- 6 - 8CU 4327
hexamethylene adipamide/hexamethylene-
azelaiamide (nylon 6:6/6:9)
hexamethylene adipamide/hexamethylene-
azelaiamide/caprolactam (nylon 6:6/6:9/6)
Also useful is nylon 6:3 produced by Dynamit Nobel.
This polyamide is the product of the dimethyl ester of
terephthalic acid and a mixtttre of isomeric trimethyl
hexamethylenediamine. Preferred nylons for the blends
of the invention include 6,6:6; 11, 12, 6:3 and 6:12.
In addition, specific polyamides are described
in U.S. Patent Nos. 2,071,250; 2,071,251; 2,130,523;
2,130,948; 2,241,322; 2,312,966; 2,512,606, issued
June 27, 1950 to Bolton et al and 3,393,210, issued
July 16, 1968 to Speck.
The polyetherimides can be obtained by any of
the methods well known to those skilled in the art
including the reaction of any aromatic bis(ether anhydrides)
of the formula O O
\ ~3 ~ Z ~ ~ \O
O O
where Z is as defined hereinbefore with an organic diamine
of the formula
H2N--R--NH2
where R is as defined hereinbefore.
Aromatic bis(ether anhydride)s of the above
formula include, for example, 2,2-bis[4-(2,3-
dicarboxyphenoxy)phenyl]-propane dianhydride; 4,4'-
bis(2,3-dicarboxyphenoxy)diphenyl ether dianhydride;
1,3-bis(2,3-dicarboxyphenoxy)benzene dianhydride;
4,4'-bis(2,3-dicarboxyphenoxy)diphenyl sulfide dianhydride;
1,4-bis(2,3-dicarboxyphenoxy)benzene dianhydride;
4,4'-bis(2,3-dicarboxyphenoxy)benzophenone dianhydride;
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- 7 - 8CU 4327
4,4'-bis(2,3-dicarboxyphenoxy)diphenyl sul~one dianhydride;
2,2-bis[4-(3,4-dicarboxyphenoxy)phenyl]propane dianhydride;
4,4'-bis(3,4-dicarboxyphenoxy)diphenyl ether dianhydride;
4,4'-bis(3,4-dicarboxyphenoxy)diphenyl sulfide dianhydride;
1,3-bis(3,4-dicarboxyphenoxy)benzene dianhydride;
1,4-bis(3,4-dicarboxyphenoxy)benzene dianhydride;
4,4'-bis(3,4-dicarboxyphenoxy)benzophenone dianhydride;
4-(2,3-dicarboxyphenoxy)-4'(3,4-dicarboxyphenoxy)diphenyl-
2,2-propane dianhydride; etc., and mixtures of such
dianhydrides.
In addition, aromatic bis(ether anhydride)s also
included by the above formula are shown by Koton, M.M.;
Florinski, F.S.; Bessonov, M.I.; Rudakow, A.P. (Institute
of Heteroorganic Compounds, Academy of Sciences, U.S.S.R.),
U.S.S.R. 257, 010, Nov. 11, 1969, Appl. May 3, 1967. In
addition, dianhydrides are shown by M.M. Koton,
F.S. Florinski, Zh Org. Khin, 4(5), 774 (1968).
Organic diamines of the above formula include,
for example, m-phenylenediamine, p-phenylenediamine,
4,4'-diaminodiphenylpropane, 4,4'-diaminodiphenylmethane,
benzidine, 4,4'-diaminodiphenyl sulfide, 4,4'-diamino-
diphenyl sulfone, 4,4'-diaminodiphenyl ether, 1,5-
diaminonaphthalene, 3,3'-diaminodiphenyl ether, 1,5-
diaminonaphthalene, 3,3'-dimenthylbenzidine, 3,3'-
dimethoxybenzidine, 2,4-bis(~ -amino-t-butyl)toluene,
bis(p-~ -amino-t-butylphenyl)ether, bis(p-~ -methyl-o-
aminopentyl)benzene, 1,3-diamino-4-isopropylbenzene,
1,2-bis(3-aminopropoxy)ethane, m-xylylenediamine,
p-xylylenediamine, 2,4-diaminotoluene, 2,6-diaminotoluene,
bis(4-aminocyclohexyl)methane, 3-methylheptamethylene-
diamine, 4,4-dimethylheptamethylenediamine, 2,11-
dodecanediamine, 2,2-dimethylopropylenediamine,
octamethylenediamine, 3-methoxyhexamethylenediamine,
2,5-dimethylhexamethylenediamine, 2,5-dimethylheptamethylene-
diamine, 3-methylheptamethylenediamine, 5-methylnona-
methyleneded:iamine, 1,4-cyclohexanediamine, lp12-octadecane-
~X~:)Z38
- 8 - 8CU 4327
diamine, bis(3-aminopropyl)sulfide, N-methyl-bis(3-amino-
propyl)amine, hexamethylenediame, heptamethylenediamine,
nonamethylenediamine, decamethylenediamine, bis(3-amino-
propyl) tetramethyldisiloxane, bis(4-aminobutyl) tetra-
methyldisiloxane, and the like.
In general, the reactions can be advantageously
carried out employing well-known solvents, e.g., o-di-
chlorobenzene, m-cresol/dianhydrides and the diamines,
at temperatures of from about 100 to about 250C.
Alternatively, the polyetherimides can be prepared by
melt polymerization of any of the above dianhydrides with
any of the above diamine compounds while heating the
mixture of the ingredients at elevated temperatures with
concurrent intermixing. Generally, melt polymerization
temperatures between about GOOO to 400C and preferably
230 to 300C can be employed. The conditions of the
reaction and the proportions of ingredients can be varied
widely depending on the desired molecular weight,
intrinsic viscosity, and solvent resistance. In general,
equimolar amounts of diamine and dianhydride are employed
for high molecular weight polyetherimides, however, in
certain instances, a slight molar excess (about 1 to 5
mole percent) of diamine can be employed resulting in the
production of polyetherimides having terminal amine groups.
Generally, useful polyetherimides have an intrinsic
viscosity greater than 0.2 deciliters per gram, preferably
0.35 to 0.60, or 0.7 deciliters per gram or even higher
than measured in m-cresol at 25C.
Included among the many methods of making the
polyetherimides are those disclosed in U.S. Patent
Nos.3,847,867, issued November 12, 1974 to Heath et al,
3,847,869, issued November 12, 1974 to Williams,
3,850,885, issued November 26, 1974 to Takekoshi et al,
3,852,242, issued December 3, 1974 to White and
3,855,178, issued December 17, 1974 to White et al.
Polyamides may be obtained by polymerizing a
~:
.
~28023~3
- 9 - ~CU 4327
monoaminomonocarboxylic acid or an internal lactam
thereof having at least two carbon atoms between the
amino and carboxylic acid groups; or by polymerizing
substantially equimolar proportions of a diamine which
contains at least two carbon atoms between the amino
groups and a dicarboxylic acid; or by polymerizing a
monoaminocarboxylic acid or an internal lactam thereof
as defined above substantially equimolecular proportions
of a diamine and a dicarboxylic acid. The dicarboxylic
acid may be used in the form of a functional derivative
thereof, for example, an ester.
The term "substantially equimolecular proportions"
(of the diamine and of the dicarboxylic acid) is used to
comprehend both strict equimolecular proportions and the
slight departures therefrom which are involved in
conventional techniques for stabilizing the viscosity of
the resultant polyamides.
As exmaples of the monoaminomonocarboxylic
acids or lactams thereof, there may be mentioned those
compounds containing from 2 to 16 carbon atoms between
the amino and carboxylic acid groups, the carbon atoms
forming a ring with the -CO-NH- group in the case of a
lactam. As particular examples of aminocarboxylic acids
and lactams there may be mentioned ~-aminocaproic acid,
butyrolactam, pivalolactam, caprolactam, capryl-lactam,
enantholactam, undecanolactam, dodecanolactam and 3-
and 4-amino benzoic acids.
Examples of suitable diamines are diamines of
the general formula H2N(CH2)nNH2 wherein n is an integer
of from 2 to 16, such as trimethylenediamine, tetramethy-
lenediamine, pentamethylenediamine, octamethylenediamine,
decamethylenediamine, dodecamethylenediamine, hexadecamethy-
lenediamine, and especially hexamethylenediamine.
C-alkylated diamines, e.g., 2,2-dimethypentamethylenediamine
and 2,2,4- and 2,4,4-trimethylhexamethylenediamine are
further examples. Other diamines which may be mentioned
- ~280Z38
- 10 - 8CU 4327
as examples are aromatic diamines, e.g., p-phenylene-
diamine, 4,4'-diaminodiphenyl sulfone, 4,4'-diamino-
diphenyl ether and 4,4'-diaminodiphenyl sulfone, 4,4'-
diaminodiphenyl ether and 4,4'-diaminodiphenylmethane;
and cycloaliphatic diamines, for example, diaminodi-
cyclohexylmethane.
The dicarboxylic acids may be aromatic, for
example, isophthalic and terephthalic acids. Preferred
dicarboxylic acids are of the :Eormula HOOC-Y-COOH
wherein Y represents a divalent aliphatic radical
containing at least two carbon atoms, and examples of
such acids are sebacic acid, octadecanedioic acid,
suberic acid, azelaic acid, undecanedioic acid, glutaric
acid, pimelic acid, and especially adipic acid. Oxalic
acid is also a preferred acid.
The blends of the present invention comprise
from 5% to 39% by weight of the polyetherimide. Preferred
blends contain from 10% to 39% by weight, most preferably
from 20% to 39% by weight polyetherimide. Within these
ranges, substantial improvements in mold shrinkage and
water absorption characteristics of the polyamide are
observed.
It is contemplated that the polyetherimide-
polyamide blends of the present invention may also include
other additive materials such as fillers, stabilizers,
plasticizers, flexibilizers, surfactant agents, pigments,
dyes, reinforcements, flame retardants and diluents in
conventional amounts. It is also contemplated that the
blends of the invention may include two or more poly-
etherimides wi-th one or more polyamides or two or more
polyamides in combination with one or more polyetherimides.
Methods for forming polyetherimide-polyamide
blends may vary considerably. Prior art blending
techniques are gen~rally satisfactory. A preferred method
comprises blending the polymers and additives such as
reinforcements in powder, granular or filamentous form,
3~3
- ll 8CU 4327
extruding the blend, and chopping the extrudate into
pellets suitable for molding by means conventionally
used to mold normally solid thermoplastic compositions.
The particular polyetherimide-polyamide blends
of the present invention have application in a wide
variety of physical shapes and forms, including the use
as films, molding compounds, coatings, etc. When used
as films or when made into molded products, these blends,
including laminated products prepared therefrom, not only
possess good physical properties at room temperature but
they retain their strength and excellent response to
workloading at elevated temperatures for long periods
of time. Films formed from the blends of this invention
may be used in application where films have been used
previously. Thus, the blends of the present invention
can be used in automobile and aviation applications for
decorative and protective purposes, and as high temperature
electrical insulation for motor slot liners, transformers,
dielectric capacitors, cable and coil wrappings (form
wound coil insulation for motors), and for containers and
container linings. The blends can also be used in
laminated structures where films or solutions of the
blend are applied to various heat resistant or other
type of materials such as asbestos, mica, glass fiber and
the like, the sheets superimposed one upon the other,
and thereafter subjecting the sheets to elevated
temperatures and pressures to effect flow and cure of
the resinous binder to yield cohesive laminated structures.
Films made from the subject polye-therimide-polyamide blends
can also serve in printed circuit applications.
~ lternatively, solutions of the blends herein
described can be coated on electrical conductors such
as copper, aluminum, and the like and thereafter the
coated conductor can be heated at elevated temperatures
to remove the solvent and to form a continuous coating
of the resinous composition thereon. If desired, an
....
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- 12 - 8CU 4327
additional overcoat may be applied -to such insulated
conductors including the use of polymeric coatings, such
as polyamides, polyesters, silicones, polyvinylformal
resins, epoxy resins, polyimides, polytetrafluorethylene,
etc. The use of the blends of the present invention as
overcoats on other types of insulation is not precluded.
Other applications which are contemplated for
these blends include their use as binders for asbestos
fibers, carbon fibers, and other fibrous materials in
making brake linings. In addition, molding compositions
and molded articles may be formed from the polymeric
blends of the invention such as by incorporating such
fillers as asbestos, glass fibers, talc, quartz, powder,
finely divided carbon, silica, and the like into the
blends prior to molding. Shaped articles may be formed
under heat, or under heat and pressure, in accordance
with practices well-known in the art.
The following examples illustrate specific
polyetherimide-polyamide blends in accordance with the
present invention. It should be understood that the
examples are given for the purpose of illustration and
do not limit the invention. In the examples, all parts
and percentages are by weight unless otherwise specified.
Example I
A series of polyetherimide-nylon 6:6 blends
was tested for mold shrinkage using the procedure o-f
ASTM test D955 in all essential details.
The polyetherimide of the blends was prepared
from the reaction products of essentially equimolar amounts
of 2,2-bis[4-(3,4 dicarboxyphenoxy)phenyl] propane
dianhydride and m-phenylene diamine produced at elevated
temperature of about 250 to about 300C and under a
nitrogen atmosphere. The polymer was extruded at about
300C to form a strand and mechanically chopped into
pellets.
The polyamide used in preparing the blends was
--` l.Z~3~23~
- 13 - 8CU 4327
a general purpose nylon 6:6 sold under the trademark
Zytel 101 by E.I. DuPont de Nemours and Co., Wilmington,
Delaware, U.S.A. Mixtures of the polyetherimide and
the polyamide were extruded in a screw type having a
temperature profile varying from about 238 to 282C
and a die temperature of about 238C to 288C. The
resulting extrudate was comminuted into pellets and
the pellets injection molded into test specimens in a
Boy molding machine having a mold temperature of about
66C. The polymers were injection molded in a disk-
shaped mold having an internal diameter of 4 inches
(10.16 cm.) and an internal thickness of 1/8 inch
(0.323 cm.). The gate was located on the periphery of
the mold. The diameter of each specimen was measured
at two points (parallel to the flow and perpendicular
to the flow) at 2-4 hours after molding and at 48 hours
after molding. Mold shrinkage was expressed as the
percent of change from the original mold dimensions.
The results are shown in Table I below. These results
demonstrate that substantial reduction in mold shrinkage
of polyamides can be achieved by blending them with
minor proportions of polyetherimides.
Example II
The polymer blends prepared by the procedures
of Example I were tested for water absorption properties
using essentially the procedures of ASTM test D570.
The polymers were injection molded into a disk-shaped
mold having an internal diameter of 2 inches (5.08 cm.)
and an internal thickness of 1/8 inch (0.32 cm.). Each
specimen was initially weighed after drying for 24 hours
at 50C and was then immersed in water at 73F (23C).
The specimens were removed from the water at intervals
of 24 hours, 4 weeks and 10 weeks, surface water was
removed by blotting and the specimens were weighed. Water
absorption was expressed as the percentage of weight
increase. The results of these tests, which are reported
1~30~3~3
- 14 - 8CU 4327
in Table II below, demonstrate that the water absorption
capacity of polyamides can be reduced signi~icantly by
blending them with minor portions of polyetherimides.
Table I
Component
Polyamides (~)
Polyetherimide (%)
Mold Shrinkage 2 hr 48 hr 2 hr 48 hr 2 hr 48 hr 2 hr 48 hr
Parallel to
Flow (%) 2.22 2.19 2.11 2.20 1.89 1.91 1.68 1.68
Perpendicular
to Flow (%) 2.34 2.34 2.18 2.22 1.84 1.87 1.48 1.51
Table II
Component
Polyamide (%) 100 95 80 61
Polyetherimide (%) - 5 20 39
Water Absorption
@2a hrs., 73F (%) 0.99 0.98 0.86 0.61
@4 weeks, 73F (%) 5.20 4.82 4.20 3.16
@10 weeks, 73F (%) 7.87 7.28 6.24 4.63
