Modified polyphenylene ether-polyamide compositions and process

Novel modified polyphenylene ether-polyamide compositions comprising polyphenylene ether, polyamide and a polycarboxylic acid and the reaction product thereof and an improved process for preparing the same.

The present invention relates to modified polyphenylene ether-polyamide 
compositions having improved chemical resistance, processability, 
elongation properties and/or impact strength as compared to unmodified 
compositions. More specifically, it relates to a resin composition which 
comprises a combination and/or the reaction product of (a) one or more 
polyphenylene ether resins, (b) one or more polyamide resins and (c) at 
least one aliphatic polycarboxylic acid or derivative modifier. 
The invention also relates to an improved process for the manufacture of 
said modified polyphenylene ether-polyamide compositions wherein the 
improvement comprises precompounding the aliphatic polycarboxylic acid 
modifier with either the polyamide or, preferably, the polyphenylene ether 
prior to compounding with the other polymer. Such precompounding 
unexpectedly results in improved physical properties in the final 
composition over those prepared from the same ingredients without 
precompounding. Inasmuch as the compositions of the present invention may 
further comprise impact modifiers, reinforcing agents, stabilizers and the 
like, these may also be precompounded with either of the polymers for 
improved properties. 
The polyphenylene ether resins are characterized by a unique combination of 
chemical, physical and electrical properties over a temperature range of 
more than 600.degree. F., extending from a brittle point of about 
-275.degree. F. to a heat distortion temperature of about 375.degree. F. 
This combination of properties renders the polyphenylene ethers suitable 
for a broad range of applications. However, in spite of the aforementioned 
beneficial properties, the usefulness of the polyphenylene ether resins is 
limited as a consequence of their poor processability, impact resistance 
and chemical resistance. 
Finholt (U.S. Pat. No. 3,379,792) discloses polymer blends wherein the 
processability of polyphenylene ether resins may be improved by blending 
therewith from 0.1 to 25% by weight of a polyamide. However, the 
advantages of the Finholt invention are limited by the fact that when the 
concentration of the polyamide exceeds 20% by weight, appreciable losses 
in other physical properties result. Specifically, there is no, or at best 
poor, compatibility between the polyphenylene ether and the polyamide such 
that phase separation of the resins occurs on molding or the molded 
article is inferior in mechanical properties. 
Ueno et al. (U.S. Pat. No. 4,315,086) discloses polyphenylene ether blends 
having improved chemical resistance without a loss of other mechanical 
properties by blending therewith a polyamide and a specific compound 
selected from the group consisting essentially of (A) liquid diene 
polymers, (B) epoxy compounds and (C) compounds having in the molecule 
both of (i) an ethylenic carbon-carbon double bond or carbon-carbon triple 
bond and (ii) a carboxylic acid, acid anhydride, acid amide, imide, 
carboxylic acid ester, amino or hydroxyl group. 
Finally, Kasahara et al. (EP46040) discloses the use of a copolymer 
comprising units of a vinyl aromatic compound and either an alpha, 
beta-unsaturated dicarboxylic acid anhydride or an imide compound thereof 
as a modifier to an impact resistant polyphenylene ether-polyamide blend 
for improved heat resistance and oil resistance. 
Applicants have now discovered novel polyphenylene ether polyamide blends 
having improved impact strength, elongation, chemical resistance, 
processability and/or heat resistance as well as reduced water absorption 
as compared to unmodified polyphenylene ether-polyamide compositions. 
Specifically, applicants have discovered novel resin compositions having 
the aforementioned properties comprising a combination of and/or the 
reaction product of a polyphenylene ether, a polyamide and a property 
improving amount of (a) an aliphatic polycarboxylic acid or derivative 
thereof represented by the formula: 
EQU (R.sup.I O).sub.m R(COOR.sup.II).sub.n (CONR.sup.III R.sup.IV).sub.s 
wherein R is a linear or branched chain, saturated aliphatic hydrocarbon of 
from 2 to 20, preferably 2 to 10, carbon atoms; R.sup.I is selected from 
the group consisting of hydrogen or an alkyl, aryl, acyl or carbonyl dioxy 
group of 1 to 10, preferably 1 to 4 carbon atoms, most preferably 
hydrogen; each R.sup.II is independently selected from the group 
consisting of hydrogen or an alkyl or aryl group of from 1 to 20 carbon 
atoms, preferably from 1 to 10 carbon atoms; each R.sup.III and R.sup.IV 
is independently selected from the group consisting essentially of 
hydrogen or an alkyl or aryl group of from 1 to 10, preferably from 1 to 
6, most preferably 1 to 4, carbon atoms; m is equal to 1 and (n+s) is 
greater than or equal to 2, preferably equal to 2 or 3, and n and s are 
each greater than or equal to zero and wherein (OR.sup.I) is alpha or beta 
to a carbonyl group and at least two carbonyl groups are separated by 2 to 
6 carbon atoms. Further, these compositions may contain stabilizing and/or 
property improving amounts of primary or secondary amines. Optionally, the 
compositions of the present invention may further comprise fillers as well 
as other property enhancing additives such as polymeric impact modifiers 
and/or inorganic reinforcing additives and/or other polymers including 
alkenyl aromatic polymers such as the styrenic polymers. 
Additionally, applicants have now discovered an improved process for the 
preparation of the said polyphenylene ether-polyamide blends. 
Specifically, while most any known process for the preparation of blend 
compositions, e.g., melt blending, may be employed in the preparation of 
the compositions of the present invention, applicants have surprisingly 
found further enhancement in impact strength, elongation, processability 
and the like by precompounding the aliphatic polycarboxylic acid modifier 
with either of the polyphenylene ether or polyamide resins prior to 
compounding with the other. Said precompounding steps may also be applied 
with respect to any additional additives employed in the preparation of 
the compositions. 
Although the exact physical configuration of the compositions of the 
present invention is not known, it is generally believed that the 
compositions comprise a dispersion of one polymer in the other. Applicants 
believe the likely configuration is wherein the polyphenylene ether is 
dispersed in a polyamide matrix, however, the inverse may also be possible 
particularly where the polyamide is present in only a minor amount. 
Applicants also contemplate that there may be present in the products 
produced hereby some graft polyphenylene ether-polyamide products. 
Furthermore, applicants contemplate that grafting, if present, may be such 
that the polycarboxylic acid may, at least in part, promote grafting 
and/or act as a graft-linking agent itself. Thus, all such dispersions as 
well as graft, partially grafted and non-grafted products are within the 
full intended scope of the invention. 
The polyphenylene ethers suitable for use in the practice of the present 
invention are well known in the art and may be prepared by any of a number 
of catalytic and non-catalytic processes from corresponding phenols or 
reactive derivatives thereof. Examples of polyphenylene ethers and methods 
for their production are disclosed in U.S. Pat. Nos. 3,306,874; 3,306,875; 
3,257,357; 3,257,358; 3,337,501 and 3,787,361, all incorporated herein by 
reference. For brevity, the term "polyphenylene ether" as used throughout 
this specification and the appended claims will include not only 
unsubstituted polyphenylene ether (made from phenol) but also 
polyphenylene ethers substituted with various substituents. The term also 
includes polyphenylene ether copolymers, graft copolymers and block 
copolymers of alkenyl aromatic compounds, especially vinyl aromatic 
compounds, as disclosed below, and a polyphenylene ether. 
Suitable phenol compounds for the preparation of the polyphenylene ethers 
may be represented by the general formula: 
##STR1## 
wherein each Q is a monovalent substituent individually selected from the 
group consisting of hydrogen, halogen, aliphatic and aromatic hydrocarbon 
and hydrocarbonoxy radicals free of a tertiary alpha-carbon atom and 
halohydrocarbon and halohydrocarbonoxy radicals free of a tertiary 
alpha-carbon atom and having at least two carbon atoms between the halogen 
atom and the phenyl nucleus, and wherein at least one Q is hydrogen. 
As specific examples of the phenol compound represented by the above 
formula, there may be given phenol; o-, m- and p- cresols; 2,6, 2,5, 2,4 
and 3,5 dimethylphenols; 2-methyl-6-phenyl-phenol; 2,6-diphenylphenol; 
2,6-diethylphenol; 2-methyl-6-ethylphenol; and 2,3,5-, 2,3,6- and 
2,4,6-trimethylphenols. Two or more phenol compounds may be used in 
combination should copolymers be desired. Additionally, copolyphenylene 
ethers may also be prepared from a phenol compound of the above general 
formula with a phenol compound not represented by the above general 
formula including, for example, a dihydric phenol such as bisphenol-A, 
tetrabromobisphenol-A, resorcinol or hydroquinione. 
Illustrative of suitable polyphenylene ethers there may be given, for 
example, poly(2,6dimethyl-1,4-phenylene)ether; 
poly(2-methyl-1,4-phenylene) ether, poly(3-methyl-1,4-phenylene)ether; 
poly(2,6-diethyl-1,4-phenylene)ether; 
poly(2-methyl-6-allyl-1,4-phenylene)ether; 
poly(2,6-dichloromethyl-1,4-phenylene)ether; 
poly(2,3,6-trimethyl-1,4-phenylene) ether; poly(2,3,5,6-tetramethyl 
phenylene)ether; poly(2,6-dichloro-1,4-phenylene)ether; 
poly(2,6-diphenyl-1,4-phenylene)ether; 
poly(2,5-dimethyl-1,4-phenylene)ether and the like. Further, as mentioned 
above, copolymers of the phenol compounds may also be used. 
Preferred polyphenylene ethers will have the formula: 
##STR2## 
where Q is as defined above and n is at least 50, preferably from about 50 
to about 200. Examples of polyphenylene ethers corresponding to the above 
formula can be found in the above referenced patents and include, among 
others: poly(2,6-dilauryl-1,4-phenylene)ether; 
poly(2,6-diphenyl-1,4-phenylene)ether; 
poly(2,6-dimethyloxy-1,4-phenylene)ether; 
poly(2,6-diethoxy-1,4-phenylene)ether; 
poly(2-methoxy-6-ethyoxy-phenylene)ether; 
poly(2-ethyl-6-stearyloxy-1,4-phenylene)ether; 
poly(2,6-dichloro-1,4-phenylene)ether; 
poly(2-methyl-6-phenyl-1,4-phenylene)ether 
poly(2,6-dibenzyl-1,4-phenylene)ether; poly(2-ethoxy-1,4-phenylene)ether; 
poly(2-chloro-1,4-phenylene)ether; poly(2,6-dibromo-1,4-phenylene) ether; 
and the like. 
For the purpose of the present invention, an especially preferred family of 
polyphenylene ethers include those having a C.sub.1 to C.sub.4 alkyl 
substitution in the two positions ortho to the oxygen ether atom. 
Illustrative members of this class are: 
poly(2,6-dimethyl-1,4-phenylene)ether; 
poly(2,6-diethyl-1,4-phenylene)ether; 
poly(2-methyl-6-ethyl-1,4-phenylene)ether; 
poly(2,6-dipropyl-1,4-phenylene)ether; 
poly(2-ethyl-6-propyl-1,4-phenylene)ether; and the like; most preferably 
poly(2,6-dimethyl-1,4-phenylene)ether. 
One method for the production of the above polyphenylene ethers is by the 
oxidation of a phenol compound by oxgen or an oxygen-containing gas in the 
presence of a catalyst for oxidative coupling. There is no particular 
limitation as to the choice of catalysts and any catalysts for oxidation 
polymerization can be employed. As typical examples of the catalyst, there 
may be given a catalyst comprising a cuprous salt and a tertiary amine 
and/or secondary amine, such as cuprous chloride-trimethylamine and 
dibutylamine, cuprous acetate-triethylamine or cuprous chloride-pyridine; 
a catalyst comprising a curpic salt, a tertiary amine, and an alkali metal 
hydroxide, such as cupric chloride-pyridine-potassium hydroxide; a 
catalyst comprising a manganese salt and a primary amine, such as 
manganese chloride-ethanolamine or manganese acetate-ethylenediamine; a 
catalyst comprising a manganese salt and an alcoholate or phenolate, such 
as manganese chloride-sodium methylate or manganese chloride-sodium 
phenolate; and a catalyst comprising a cobalt salt and a tertiary amine. 
Polyamides suitable for the preparation of the compositions of the present 
invention may be obtained by polymerizing a monoamino-monocarboxylic acid 
or a lactam thereof having at least 2 carbon atoms between the amino and 
carboxylic acid group; or by polymerizing substantially equimolar 
proportions of a diamine which contains at least 2 carbon atoms between 
the amino groups and a dicarboxylic acid; or by polymerizing a 
monoaminocarboxylic acid or a lactam thereof as defined above together 
with 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 or acid chloride. 
The term "substantially equimolecular" proportions (of the diamine and of 
the dicarboxylic acid) is used to cover both strict equimolecular 
proportions and slight departures therefrom which are involved in 
conventional techniques for stabilizing the viscosity of the resultant 
polyamides. 
Examples of the aforementioned monoamino-monocarboxylic acids or lactams 
thereof which are useful in preparing the polyamides include those 
compounds containing from 2 to 16 carbon atoms between the amino and 
carboxylic acid groups, said 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- aminobenzoic 
acids. 
Diamine suitable for use in the preparation of the polyamides include the 
straight chain and branched, alkyl, aryl and alkyl-aryl diamines. Such 
diamines include, for example, those represented by the general formula: 
EQU H.sub.2 N(CH.sub.2).sub.n NH.sub.2 
wherein n is an integer of from 2 to 16, such as trimethylenediamine, 
tetramethylenediamine, pentamethylenediamine, octamethylenediamine and 
especially hexamethylenediamine, as well as trimethyl hexamethylene 
diamine, meta-phenylene diamine, meta-xlylene diamine and the like. 
The dicarboxylic acids may be aromatic, for example isophthalic and 
terephthalic acids. Preferred dicarboxylic acids are of the formula 
EQU HOOC--Y--COOH 
wherein Y represents a divalent aliphatic group containing at least 2 
carbon atoms, and examples of such acids are sebacic acid, octadecanedoic 
acid, suberic acid, glutaric acid, pimelic acid and adipic acid. 
Typical examples of the polyamides or nylons, as these are often called, 
include for example polyamides 6, 6/6, 11, 12, 6/3, 6/4, 6/10 and 6/12 as 
well as polyamides resulting from terephthalic acid and/or isophthalic 
acid and trimethyl hexamethylene diamine, polyamides resulting from adipic 
acid and meta xylylenediamines, polyamides resulting from adipic acid, 
azelaic acid and 2,2-bis-(p-aminocyclohexyl)propane and polyamides 
resulting from terephthalic acid and 4,4'-diamino-dicyclohexylmethane. 
Mixtures and/or copolymers of two or more of the foregoing polyamides or 
prepolymers thereof, respectively, are also within the scope of the 
present invention. Preferred polyamides are the polyamides 6, 6/6, 11 and 
12, most preferably polyamide 6/6. 
It is also to be understood that the use of the term "polyamides" herein 
and in the appended claims is intended to include the toughened or super 
tough polyamides. Super tough polyamides, or super tough nylons, as they 
are more commonly known, are available commercially, e.g. from E. I. 
duPont under the tradename Zytel ST, or may be prepared in accordance with 
a number of U.S. Pat. Nos. including, among others, Epstein U.S. Pat. No. 
4,174,358; Novak U.S. Pat. No. 4,474,927; Roura U.S. Pat. No. 4,346,194; 
and Joffrion U.S. Pat. No. 4,251,644, herein incorporated by reference. 
These super tough nylons are prepared by blending one or more polyamides 
with one or more polymeric or copolymeric elastomeric toughening agents. 
Suitable toughening agents are disclosed in the above-identified U.S. Pat. 
Nos. as well as in Caywood, Jr. U.S. Pat. No. 3,884,882 and Swiger U.S. 
Pat. No. 4,147,740 and Gallucci et al., "Preparation and Reactions of 
Epoxy-Modified Polyethylene", J. APPL. POLY. SCI., V. 27, pp. 425-437 
(1982) herein incorporated by reference. Typically, these elastomeric 
polymers and copolymers may be straight chain or branched as well as graft 
polymers and copolymers, including core-shell graft copolymers, and are 
characterized as having incorporated therein either by copolymerization or 
by grafting on the preformed polymer, a monomer having functional and/or 
active or highly polar groupings capable of interacting with or adhering 
to the polyamide matrix so as to enhance the toughness of the polyamide 
polymer. 
The blending ratio of polyphenylene ether to polyamide is 5 to 95% by wt. 
preferably 30 to 70% by wt. of the former to 95 to 5% by wt., preferably 
70 to 30% by wt. of the latter. When the polyamide is less than 5 wt. 
percent, its effect to improve solvent resistance is small, while when it 
exceeds 95 wt. percent, thermal properties such as heat distortion 
temperature tend to become poor. 
Compounds useful for improving the physical properties of the polyphenylene 
ether-polyamide compositions are aliphatic polycarboxylic acids and 
derivatives thereof represented by the formula: 
EQU (R.sup.I O).sub.m R(COOR.sup.II).sub.n (CONR.sup.III R.sup.IV).sub.s 
wherein R is a linear or branched chain, saturated aliphatic hydrocarbon of 
from 2 to 20, preferably 2 to 10, carbon atoms; R.sup.I is selected from 
the group consisting of hydrogen or an alkyl, aryl, acyl or carbonyl dioxy 
group of 1 to 10, preferably 1 to 6, most preferably 1 to 4, carbon atoms, 
especially preferred is hydrogen; each R.sup.II is independently selected 
from the group consisting of hydrogen or an alkyl or aryl group of from 1 
to 20 carbon atoms, preferably from 1 to 10 carbon atoms; each R.sup.III 
and R.sup.IV is independently selected from the group consisting 
essentially of hydrogen or an alkyl or aryl group of from 1 to 10, 
preferably from 1 to 6, most preferably 1 to 4, carbon atoms; m is equal 
to 1 and (n+s) is greater than or equal to 2, preferably equal to 2 or 3, 
and n and s are each greater than or equal to zero and wherein (OR.sup.I) 
is alpha or beta to a carbonyl group and at least two carbonyl groups are 
separated by 2 to 6 carbon atoms. Obviously, R.sup.I, R.sup.II, R.sup.III 
and R.sup.IV cannot be aryl when the respective substituent has less than 
6 carbon atoms. 
In general the polycarboxylic acid modifiers suitable for use herein 
encompass three classes, the polycarboxylic acids, the acid esters and the 
acid amides. Thus, when used herein and in the appended claims, it is to 
be understood that the term "polycarboxylic acid" refers to all these 
classes. Illustrative of suitable polycarboxylic acids there may be given 
citric acid, malic acid, and agaricic acid; including the various 
commercial forms thereof, such as, for example, the anhydrous and hydrated 
acids. Illustrative of acid esters useful herein include for example, 
acetyl citrate and mono- and/or di- stearyl citrates and the like. 
Suitable acid amides useful herein include for example N,N'-diethyl citric 
acid amide; N,N'-dipropyl citric acid amide; N-phenyl citric acid amide; 
N-dodecyl citric acid amide; N,N'-didodecyl citric acid amide and 
N-dodecyl malic acid amide. Derivatives of the foregoing polycarboxylic 
acids are also suitable for use in the practice of the present invention. 
Especially preferred derivatives are the salts thereof, including the 
salts with amines and/ preferably, the alkali and alkaline metal salts. 
Exemplary of suitable salts include calcium malate, calcium citrate, 
potassium malate and potassium citrate. 
The amount of the polycarboxylic acid to be used is that amount which 
manifests property improvement, especially improved compatibility as well 
as improved processability, impact strength and/or elongation, in the 
polyphenylene ether-polyamide compositions. In general, the amount of 
polycarboxylic acid compounds used will be up to about 4%, preferably from 
about 0.05 to about 4%, most preferably from about 0.1 to about 2% by 
weight based on the total composition. Although higher amounts may be 
used, the preparation of such compositions causes significant problems in 
processing resulting in compositions having large die-swell and/or may not 
give optimum property improvement. The specific amount of the 
polycarboxylic acid compound to be used to achieve optimum results for a 
given composition is dependent, in part, on the specific polycarboxylic 
acid and polymers used, the weight ratio of said polymers and the 
processing conditions. 
In addition to the improved processability impact strength and elongation, 
many of the compositions prepared in accordance with the present invention 
manifest improvements in other physical properties and characteristics 
including for example, reduced water absorption. 
The above-mentioned property improving polycarboxylic acid compound may be 
used alone or in combination with a primary or secondary amine. The 
presence of the amine is found to enhance the improvement of certain 
physical properties, especially brightness, when used in combination with 
various polycarboxylic acids, especially for example with malic acid. 
Suitable amines include those primary and secondary amines having from 1 
to about 20, preferably from 1 to about 10 carbon atoms. Illustrative of 
said suitable amines there may be given, methyl ethylamine, diethylamine, 
butylamine, dibutylamine, analine, n-octadecylamine and the like. The 
amount of the primary or secondary amine to be used is generally up to 
about 3% by wt., preferably from about 0.35 to about 1% by wt. 
In the practice of the present invention, it may be further desirable to 
add an additional modifier resin or resin combination to further improve 
the physical properties, particularly the impact strength, and/or 
processability of the composition. Such modifier resins are well known in 
the art and are typically derived from one or more monomers selected from 
the group consisting of olefins, vinyl aromatic monomers, acrylic or alkyl 
acrylic acids and their ester derivatives as well as conjugated dienes. 
Especially preferred modifier resins are the rubbery high-molecular weight 
materials including natural and synthetic polymeric materials showing 
elasticity at room temperature. Suitable modifier resins include both 
homopolymers and copolymers, including random, block, radial block, graft 
and core-shell copolymers as well as combinations thereof. 
Polyolefins or olefin-based copolymer employable in the practice of the 
present invention include, among others, low density polyethylene, high 
density polyethylene, linear low density polyethylene, isotactic 
polypropylene, poly(1-butene), poly(4-methyl-1-pentene), 
propylene-ethylene copolymers, and the like. Additional olefin copolymers 
include copolymers of one or more alpha olefins, particularly ethylene, 
with copolymerizeable monomers including for example vinyl acetate, 
acrylic acids and alkyl acrylic acids as well as the ester derivatives 
thereof including for example, ethylene acrylic acid, ethylacrylate, 
methacrylic acid, methyl methacrylate and the like. Finally, an additional 
class of olefin-based copolymers suitable for use herein include the 
ionomer resins, which may be wholly or partially neutralized with metal 
ions. 
A second class of modifier resins employable herein are those derived from 
the vinyl aromatic monomers. These include, for example, modified and 
unmodified polystyrenes, ABS type graft copolymers; AB and ABA type block 
and radial block copolymers and vinyl aromatic conjugated diene core-shell 
graft copolymers. Modified and unmodified polystyrenes include 
homopolystyrenes and rubber modified polystyrenes, such as butadiene 
rubber modified polystyrene otherwise referred to as high impact 
polystyrene or HIPS. Additional useful polystyrenes include copolymers of 
styrene and various monomers, including for example, 
poly(styrene-acrylonitrile) (SAN), styrene-butadiene copolymers as well as 
the modified alpha and para substituted styrenes and any of the styrene 
resins disclosed in U.S. Pat. No. 3,383,435, herein incorporated by 
reference. ABS type of graft copolymers are typified as comprising a 
rubbery polymeric backbone derived from a conjugated diene alone or in 
combination with a monomer copolymerizable therewith having grafted 
thereon at least one monomer, and preferably two, selected from the group 
consisting of monoalkenyl arene monomers and substituted derivatives 
thereof as well as acrylic monomers such as acrylonitriles and acrylic and 
alkyl acrylic acids and their esters. 
An especially preferred class of vinyl aromatic monomer derived polymer 
resins are the block copolymers comprising monoalkenyl arene blocks and 
hydrogenated, partially hydrogenated and non-hydrogenated conjugated diene 
blocks and represented as AB and ABA block copolymers. Suitable AB type 
block copolymers are disclosed in for example U.S. Pat. Nos. 3,078,254; 
3,402,159; 3,297,793; 3,265,765; and 3,594,452 and UK Patent No. 
1,264,741, all herein incorporated by reference. Exemplary of typical 
species of AB block copolymers there may be given: 
polystyrene-polybutadiene (SBR) 
polystyrene-polyisoprene and 
poly(alpha-methylstyrene)-polybutadiene. 
Such AB block copolymers are available commercially from a number of 
sources including Phillips under the trademark Solprene. 
Additionally, ABA triblock copolymers and processes for their production as 
well as hydrogenation, if desired, are disclosed in U.S. Pat. Nos. 
3,149,182; 3,231,635; 3,462,162; 3,287,333; 3,595,942; 3,694,523 and 
3,842,029, all incorporated herein by reference. 
Exemplary of typical species of triblock copolymers there may be given: 
polystyrene-polybutadiene-polystyrene (SBS) 
polystyrene-polyisoprene-polystyrene (SIS) 
poly(alpha-methylstyrene)-polybutadiene-poly(alpha-methylstyrene) and 
poly(alpha-methylstyrene)-polyisoprene-poly(alpha-methystyrene). 
A particularly preferred class of such triblock copolymers are available 
commercially as CARIFLEX.RTM., KRATON D.RTM. and KRATON G.RTM. from Shell. 
A third class of modifier resins suitable for use in the instant invention 
are those derived from conjugated dienes. While many copolymers containing 
conjugated dienes have been discussed above, additional conjugated diene 
modifier resins include for example homopolymers and copolymers of one or 
more conjugated dienes including for example polybutadiene, 
butadiene-styrene copolymers, isoprene-isobutylene copolymers, 
chlorobutadiene polymers, butadiene-acrylonitrile copolymers, 
polyisoprene, and the like. Finally, ethylene-propylene-diene monomer 
rubbers are also intended to be within the full scope of the present 
invention. These EPDMs are typified as comprising prodominately ethylene 
units, a moderate amount of propylene units and only a minor amount, up to 
about 20mole % of diene monomer units. Many such EPDM's and processes for 
the production thereof are disclosed in U.S. Pat. Nos. 2,933,480; 
3,000,866; 3,407,158; 3,093,621 and 3,379,701, herein incorporated by 
reference. 
An additional group of modifier resins employable in the instant invention 
are the core-shell type graft copolymers. In general, these are 
characterized as having a predominately conjugated diene rubbery core or a 
predominately cross-linked acrylate rubbery core and one or more shells 
polymerized thereon and derived from monoalkenyl arene and/or acrylic 
monomers alone or, preferably, in combination with other vinyl monomers. 
Such core-shell copolymers are widely available commercially, for example, 
from Rohm and Haas Company under the tradenames KM-611, KM-653 and KM-330, 
and are described in U.S. Pat. Nos. 3,808,180; 4,034,013; 4,096,202; 
4,180,494 and 4,292,233. 
Also within the scope of the present invention are the core-shell 
copolymers wherein an interpenetrating network of the resins employed 
characterizes the interface between the core and shell. Especially 
preferred in this regard are the ASA type copolymers available from 
General Electric Company and sold as GELOY.TM. resin and described in U.S. 
Pat. No. 3,944,631. 
It is also to be understood that in addition to the straight polymers and 
copolymers described above, there may be employed such polymers and 
copolymers having copolymerized therewith or grafted thereon monomers 
having functional groups and/or polar or active groups. Such 
functionalized or activated polymers and copolymers are described in the 
above-mentioned Epstein, Novak, Roura, Joffrion, Caywood, Swiger and 
Gallucci references cited above with respect to the discussion on 
toughened polyamides. All of such functionalized or activated polymers and 
copolymers may be directly blended with the ingredients to the present 
compositions or, as described above, may be precompounded with a polyamide 
or polyphenylene ether. Finally, other suitable modifier resins and high 
molecular weight rubbery materials which may be employed in the practice 
of the present invention include for example thiokol rubber, polysulfide 
rubber, polyurethane rubber, polyether rubber (e.g. polypropylene oxide), 
epichlorhydric rubber, ethylene propylene rubber, thermoplastic polyester 
elastomers, thermoplastic ether-ester elastomers and the like. 
The amount of the rubbery polymer used will be up to about 100 parts by 
weight, preferably from about 5 to about 50 parts by weight based on 100 
parts by weight of a mixture of polyphenylene ether and polyamide. 
However, when the amount is less than 2 parts by weight, the effect of the 
rubbery polymer to improve impact resistance is poor. When the amount is 
more than 100 parts by weight, the impact resistance is much improved, 
however, some loss of other physical properties may result. Thus, in the 
interest of balancing impact resistance and other physical properties, it 
is preferred to use less than 100 parts by weight of the rubbery polymer. 
It is also to be understood that combinations of the above-mentioned 
modifier resins may be employed and are within the full intended scope of 
the present invention. 
Finally, in addition to the foregoing, the polyphenylene ether-polyamide 
resin compositions of the present invention may further comprise other 
reinforcing additives, including glass fibers, carbon fibers, mineral 
fillers and the like as well as various flame retardants, colorants, 
stabilizers and the like known to those skilled in the art. 
When employed in the practice of the present invention, reinforcing 
additives should be used in an amount up to no more than about 50 wt. % 
based on the total composition, preferably no more than about 30 wt. %. 
Especially preferred reinforcing additives are the filamentous and chopped 
glass fibers. Such glass fibers may be untreated or, preferably, treated 
with a silane or titanate coupling agent, and are well known in the art 
and widely available from a number of manufacturers. 
Suitable stabilizers for use in the practice of the present invention 
generally include most any of the known thermal and oxidative stabilizers 
suitable for use with either polyamides or polyphenylene ethers. 
Especially preferred are those stabilizers suitable for use with 
polyamides. For example, liquid phosphates and hindered phenols may be 
employed as well as stabilizer packages encompassing combinations of 
hindered phenols and potassium and cuprous salts. 
The method for producing the resin compositions of the present invention is 
not particularly limited, and the conventional methods are satisfactorily 
employed. Generally, however, melt blending methods are desirable. The 
time and temperature required for melt-blending are not particularly 
limited, and they can properly be determined according to the composition 
of the material. The temperature varies somewhat with the blending ratio 
of the polyphenylene ether to polyamide, but it is generally within a 
range of 270.degree. to 350.degree. C. A prolonged time and/or a high 
shear rate is desirable for mixing, but the deterioration of the resin 
composition advances. Consequently, the time needs to be determined taking 
into account these points. 
Any of the melt-blending methods may be used, if it can handle a molten 
viscous mass. The method may be applied in either a batchwise form or a 
continuous form. Specifically, extruders, Bambury mixers, rollers, 
kneaders and the like may be exemplified. 
While all ingredients may be initially and directly added to the processing 
system, applicants have surprisingly found that the physical properties of 
the composition, particularly impact strength and elongation, are greatly 
enhanced by initially precompounding one of the polymer resins, preferably 
the polyphenylene ether, with the polycarboxylic acid prior to blending 
with the other polymer. Such precompounding may be done in two steps 
wherein the polycarboxylic acid and the polyphenylene ether are melt 
extruded to form pellets which are then blended through extrusion with the 
polyamide or one can employ an extrusion apparatus or melt blending 
apparatus wherein the polyphenylene ether and polycarboxylic acid are fed 
at the throat of the screw and the polyamide is subsequently added to the 
extrusion system in a downstream feed port. In this latter method, the 
polycarboxylic acid and polyphenylene ether are melt blended and in a 
molten state when the polyamide is added. 
With respect to the other ingredients of the compositions, all ingredients 
may be directly added to the processing system or certain additives may be 
precompounded with each other or either polymer product blending with the 
other polymer. For example, as discussed above, impact modifier or 
toughening agents may be precompounded with a polyamide to form a super 
tough polyamide. Alternatively, the polyphenylene ether may be 
precompounded with the rubber polymer or other additional resin and the 
polycarboxylic acid and subsequently compounded with the polyamide. 
Furthermore, the amine compound, if used, may be premixed and/or reacted 
with a polycarboxylic acid and precompounded with a polyphenylene ether 
prior to compounding with a polyamide. In essence, any system of 
precompounding may be employed in the practice of the present invention; 
however, the tremendous and unexpected improvement and physical properties 
is most apparent when at a minimum the polycarboxylic acid is 
precompounded with the polyphenylene ether. While the polycarboxylic acid 
may be precompounded with a polyamide, the enhancement and physical 
properties is not as great. 
The following examples are presented in order that those skilled in the art 
may better understand how to practice the present invention. These 
examples are merely presented by way of illustration and are not intended 
to limit the invention thereto. Unless otherwise stated, all formulations 
are expressed in terms of parts by weight.