CA1186095A - Nitrogen-containing polymer and polyester-carbonate blends - Google Patents

Abstract

Abstract of the Disclosure Novel thermoplastic compositions having improved heat distortion and strength characteristics are disclosed which comprise blends of:
(a) a polyester-carbonate resin; and (b) at least one polymer selected from the group consisting of (i) polyamides, (ii) polyimides, (iii) polyamideimides, and (iv) mixtures thereof.

Description

NITROGEN-CONTAINING POLYMER AND
POLYESTER-CARBONATE BLENDS

This invention is directed to a thermoplastic com-position comprised of a blend of polymers. More particularly it is directed to a blend of (a) a polyester-carbonate resin, and (b) at least one polymer selected from the group consisting of (i) polyamides, (ii) polyimides, and (iii) polyamideimides.

BACKGROUND OF THE IWVEWTION

Polyester-carbonates are known thermoplastic resins whose many excellent physical properties allow them to be used successfully in many commercial and industrial applications.
This is especially true of aromatic polyester-carbonates.
However, in some applications a material having a high heat distortion temperature, higher flexural strength and greater tensile strength than aromatic polyester-carbonate resin is re~uired.
The addition of various additives in attempting to provide an aromatic polyester-carbonate resin which has a higher heat distortion temperature, higher flexural strength and greater tensile strength have produced mixed results.
In some instances there was no improvement in the heat distortion temperature, flexural strength, or the tensile strength o~ the polymer. In other instances the addition of certain additives to the aromatic polyester-carbonate resulted in a polymer having a higher heat distortion temperature, higher flexural strength and grea-ter tensile strength, but this was accomplished only at the expense of some of the other valuable properties of the polyester-carbonate.

This is due to the fact, well known to those skilled in the art, that the area of modification of the physical properties of a polymer by the addition of various additives thereto is largely an empirical art rather than ~ 8CL-3558 a predictable science with little, if any, predictability on the effects a particular additive will have in a particular polymer.
Thus, while a particular additive may have one effect in one polymer system the same additive may well produce entirely different results when used in another and different polymer system. Likewise, two rather closely related additives may produce entirely different results when added to the same polymer system.
There thus exists a need for an aromatic polyester-carbonate resin which has a higher heat dis-tortion temperature, greater tensile and flexural strength, and yet retains all of the advantageous physical properties of an unmodified aromatic polyester-carbonate.
DESCRIPTION OF THE INVENTION
The instant invention is directed to novel thermoplastic compositions containing a blend of (a) an aromatic polyester-carbonate resin, and (b) at least one resin selected from the group consisting of (i) poly-amides, (ii) polyimides, and (iii) polyamideimides.
These compositions have improved heat distortion temper-atures, flexural strength and tensile strength compared to unmodified aromatic polyester-carbonates.
The polyester-carbonates which find use in the instant invention and the methods for their preparation are well known in the art as disclosed in U.S. Patent Nos.
3,303,331 to Donald R. Biegel, issued February 7, 1967;
3,169,121 to Eugene P. Goldberg, issued February 9, 1965;

4,194,038 to Josefina T. Baker et al, issued March 18, 1980;
and 4,156,069 to Dusan C. Prevorsek et al, issued ~ay 22, 1979; as well as in Canadian application Serial No. 350,529 filed April 24, 1980 and assigned to the same assignee as the instant application.

~ 8CL-3558 The polyester-carbonates can generally be termed copolyesters containing carbonate groups, carboxy-late groups, and aromatic carbocyclic groups in the polymer chain, in which at least some of the carboxylate groups and at least some of the carbonate groups are bonded directly to ring carbon atoms of the aromatic carbocyclic groups. These polyester-carbonates are, in general, prepared by reacting a difunctional carboxylic acid or a reactive derivative of the acid such as the acid dihalide, a dihydric phenol and a carbonate precursor.
The dihydric phenols useful in Eormulating the polyester-carbonates which are of use in the practice of the present invention are in general, represented by the general formula :
r ~ r HO ¦ A - _ -E I - A ~ ~ OH
- L_ _ t _ ~ s _ _ u wherein A represents an aromatic group such as phenylene, biphenylene, napthylene, etc. E may be an alkylene or alkylidene group such as methylene, ethylene, propylene, propylidene~ isopropylidene, butylene, butylidend, iso-butylidene, amylene, isoamylene, amlidene, isoamylidene, etc. Where E is an alkylene or alkylidene group, it may also consist of two or more alkylene or alkylidene groups connected by a non-alkylene or non-alkylidene group such as an aromatic linkage, a tertiary amino linkage, an ether linkage, a carbonyl linkage, a silicon-containing linkage, or by a sulfur-containing linkage such as sulfide, sulfoxide, sulfone, etc. In addition, E may be a cyclo-aliphatic group (e.g., cyclopentyl, cyclohexyl, etc.); a sulfur-containing linkage, such as sulfide, sulfoxide or sulfone; an ether linkage; a carbonyl group; a -tertiary ni-trogen group; or a silieon-containing linkage sueh as silane or siloxy. Other groups whieh E may represent will oceur to those skilled in the art. R represents hydrogen or a monovalent hydrocarbon group such as alkyl (methyl, ethyl, propyl, etc.), aryl (phenyl, naphthyl, etc.)/
aralkyl (benzyl, ethylphenyl, etc.), or eycloaliphatie (cyclopentyl, cyclohexyl, etc.). _ may be an inorganic atom such as halogen (fluorine, bromine, chlorine, iodine), an inorganic group such as the nitro group, an organic group sueh as R above, or an oxy group such as OR, it being only necessary that Y be inert to and unaffected by the reaetants and reaction conditions. The letter _ represents any integer from and including zero through the number of positions on A available for substitu-tion;
p represents an integer from and including zero through the number of positions on E available for substitution;
t represents an integer equal to at least one; s is either zero or one; and u represents an integer including zero.
In the dihydric phenol compound represented by Formula I above, when more than one Y substituent is present, they may be the same or different. The same holds true for the R substituent. Where s is zero in Formula I and _ is not zero, the aromatie rings are direetly joined with no intervening alkylene or o-ther bridge. The positions of the hydroxyl groups and Y on the aromatie nuelear residues A ean be varied in the ortho,me-ta r or para positions and the groupings ean be in a vieinal, asymmetrieal or symmetrical relationship, where two or more ring carbon atoms of the hydrocarbon residue are substituted with Y and hydroxyl groups.
Some nonlimiting examples of dihydric phenols falling within the seope of Formula I inelude:

~ 8CL-3558

2,2-bis(4-hydroxyphenyl)propane (bisphenol A);
2,4'-dihydroxydiphenylmethane;
bis(2-hydroxyphenyl)methane;
bis(4-hydroxyphenyl)methane;
bis(4-hydroxy-5-nitrophenyl)methane;
bis(4-hydroxy-2,6-dimethyl-3-methoxyphenyl)methane;
1,1-bis(4-hydroxyphenyl)ethane;
1,1-bis(4-hydroxy-2-chlorophenyl)ethane;
2,2-bis(3-phenyl-4-hydroxyphenyl)propane;
bis-(4-hydroxyphenyl)-cyclohexylmethane; and 2,2-bis(4-hydroxyphenyl)-1-phenykpropane.
These dihydric phenols may be used alone or as mixtures of two or more different dihydric phenols.
In general, any difunctional carboxylic acid, or its reactive derivative such as the acid dihalide, conventionally used in the preparation of polyesters may be used for the preparation of the polyester-carbonates useful in formulating the compositions of the prepsent invention. In general~ the carboxylic acids which may be used are aliphatic carboxylic acids, aliphatic~aromatic carboxylic acids, or aromatic car-boxylic acids. The aromatic dicarboxylic acids or their reactive derivatives such as the aromatic acid dihalides are preferred as they produce the aromatic polyester-carbonates which are most useful in the practice of the present invention.
These carboxylic acids may be represented by the general formula:

II. R2 [Rl ~ - COOH

wherein R represents an alkylene, alkylidene or cycloaliphatic group in the same manner as se-t out above ~CL-3553 for E in Formula I; an alkylene, alkylidene, or cyclo-aliphatic group containing ethylenic unsaturation; an aromatic radical such as phenylene, naphthylene, sub-stituted phenylene, etc.; two or more aromatic groups connected through non-aromatic linkages such as those defined by E in Formula I; or an aralkyl radical such as tolylene, xylene r etc. R2 is either a carboxyl or a hydroxyl group. The letter q represents one where R is a hydroxyl group and either zero or one wherein R2 is a carboxyl group. Thus the difunctional acid will either be a monohydroxy monocarboxylic acid or a dicarboxylic acid. For purposes of the present invention the dicarboxylic acids or their reactive derivatives such as the acid dihalides are preferred, with the aromatic dicarboxylic acids or their dihalides being more preferred. Thus, in these more preferred acids R is a carboxyl groups and R is an aromatic radical such as phenylene, naphthylene, biphenylene, substituted phenylene, etc; two or more aromatic groups connected through non aromatic linkages; or an aralkyl group. Some nonlimiting examples of suitable preferred aromatic and aliphatic-aromatic dicarboxylic acids which may be used in preparing the polyester-carbonates useful in the practice of the present invention include phthalic acid, isophthalic acid, terephthalic acid, homophthalic acld, o-, m- and p-phenylenediacetic acid; the polynuclear aromatic acids such as diphenic acid, and 1,4-naphthalic acid.
These acids may be used either individually or as a mixture of two or more different acids.

The carbonate precursor may be either a carbonyl halide, a carbonate es-ter or a haloformate.
The carbonyl halides which can be employed are carbonyl ~6~ 8CL-3558 chloride, carbonyl bromide and mixtures -thereof.
Typical of carbonate esters which may be employed herein are diphenyl carbonate, di(halophenyl) carbonates such as di(chlorophenyl)carbonate, di(bromophenyl)carbonates, di(trichlorophenyl)earbonate, di(tribromophenyl)carbonate, etc., di(al]cylphenyl)earbonates such as di(tolyl)carbonate, etc., di(naphthyl)carbonate, di(chloronathyl)carbonate, phenyl tolyl carbonate, chlorophenyl chloronaphthyl carbonate, etc., or mixtures thereof. The haloformates suitable for use herein include bishaloformates of dihydric phenols (bischloroformates of hydroquinone, etc) or glyeols (bishaloformates of ethylene glycol, neopentyl glycol, polyethylene glyeol, ete.). Carbonyl ehloride, also known as phosgene, is preferred.
Also present during the eo-reaetion between the dihydrie phenol, the earbonate preeursor and the diearboxylie aeid or its reaetive derivative are catalysts, molecular weight regulators, and acid aceeptors.
Examples of suitable moleeular weight regulators include phenol, tertiary butyl phenol ete. Examples of suitable eatalysts inelude tertiary amines, quaternary ammonium eompounds, quaternary phosphonium eompounds, ete.
Examples of suitable aeid aeeeptors inelude tertiary amines, alkali or alkaline earth metal hydroxides, e-tc.
The polyester-carbonates which are useful in -the practiee of the present invention are the aromatie polyester-earbonates derived from dihydrie phenols, aromatie diearboxylie aeids or thier reaetive derivatives such as the aromatic aeid dihalides, e.g., diehlorides and phosgene. A quite useful elass of aromatie polyester-carbonates are those derived from bisphenol A; terephthalic acid, isopthalic acid, or a mixture of isphthalic and ~6~ 8CL-3558 terephthalic acids or isophthaloyl chloride, terephthaloyl chloride, or a mixture of isophthaloyl and terephthaloyl chloride; and phosgene. If a mixture of terephthaloyl and isophthaloyl dichloride is present the ratio by weight of terephthaloyl dichloride to isophthaloyl dichloride is from about 5:95 to 95:5.
The instant invention is direc-ted to novel compositions, more particularly novel thermoplastic molding compositions, containing polymer blends comprised Of (a) an aromatic polyester-carbonate resin; and (b) at least one polymer selected from the group consisting of (i) polyamides, (ii) polyimides, and (iii) polyamideimides.
The polyamides and their preparation are well known to those skilled in the general formula III. (~ b (R~ c I C ~ - C _ N ~ Nl6 wherein each R3 and each R5 are independently selected from alkyl radicals of from 1 to about 12 carbon atoms, halogen radicals, and substituted alkyl radicals containing from 1 to about 12 carbon atoms and substi-tuent grops such as halogen and/or oxy groups such as oR7 wherein R7 is an alkyl group containing from 1 -to about 10 carbon atoms; R~ and R6 are independently selected from alkyl radicals of from 1 to about 12 carbon atoms, hydrogen, aryl radicals of from 6 to 18 carbon atoms, aralkyl radicals of from 7 to 18 carbon atoms, and ~ 8CL-3558 alkaryl radicals of from 7 to 18 carbon atoms; and _ represents a number having a value from 10 to about 500;
_ represents an integer having a value from O to the number of replaceable hydrogen atoms on the aromatic ring, i.e, 4, inclusive.
Illustrative of compounds falling within the scope of Formula III is one wherein b and _ are 0, and R4 and R6 represent hydrogen. Such polyamides are marketed by the E.I. DuPont Company under the tradename Nomex and Kevlar.
The polyamideimides and their preparation are likewise well known to those skilled in the art. For purposes of the present invention the aromatic polyamidei-mides are preferred. These aromatic polyamideimides are represented by the general formula _ _ I~ N - R _ N ~ -O O

wherein each R10 is independently selected from the yroup consisting of alkyl radicals of from 1 to about 12 carbon atoms, halogen, and substituted alkyl radicals containing from 1 to about 12 carbon atoms and substituen-t groups such as halogen and/or oxy groups represented by the formula ORll wherein Rll is an alkyl radical of from 1 to about 12 carbon atoms; R is selected from the group consisting of hydrogen, alky]
radicals of from 1 to about 12 carbon atoms, aryl radicals of from 6 to 18 carbon atoms, aralkyl radicals of from ~ 8CL-3558 7 to about 18 carbon atoms and aralkyl radicals of from 7 to about 18 carbon atoms. R in Formula IV is selected from the group consisting of divalent aromatic organic radicals having from 6 to bout 30 carbon atoms;
a~kylene radicals having from 2 to about 20 carbon atoms;
alkylidene radicals having from 2 to about 20 carbon atoms; and cycloalkylene radicals containing from about

3 to about 8 carbon atoms. Radicals included by R8 are, for example, aromatic hydrocarbon radicals and halogenated aromatic hydrocarbon radicals, for example, phenylene, tolylene, chlorophenylene, naphthylene, etc. The letter e represents an integer having a value from 0 -to the number of replaceable hydrogen atoms present on the aromatic ring, i.e., 3, inclusive; and d is a number having a value from about 10 to about 500.
Illustrative of compounds falling within the scope of Formula IV is one wherein is 0. R is hydrogen and R8 is an alkylene or arylene radical. Such poly-amideimides are marketed by the Amoco Corporation under the tradename Torlon.
The polyimides are also known compounds whose preparation and properties are well known to those skilled in the art. For the purposes of the instant invention, the polyetherimides are the preferred poly-imides. The polyetherimides are disclosed in U.S.
Patent Nos. 3,803,085 to Tohru Takehoshi et al, issued April 9, 1974; and 3,905,942 to Tohru Takehoshi et al, issued September 16, 1975. These polyetherimides are represented by the general formula:

~86~5 8CL-3558 V.

~ o_RlL~ o ~"\

10 wherein f has a value from about 10 to about 500; and R
is a divalent aliphatic hydrocarbon radical containing from 2 to about 12 carbon atoms, a divalent aromatic hydrocarbon or halogenated hydrocarbon radical containing from 6 to 18 carbon atoms, or a divalent cycloaliphatic hydrocarbon radical containing from 3 to about 10 carbon atoms. Rll is a divalent aromatic organic radical having rom 6 to 30 carbon atoms. Radicals included by Rll are, for example, aromatic hydrocarbon radicals and halogenated aromatic hydrocarbon radicals for example, phenylene, tolylene, chlorophenylene, naphthalene, etc.~ and radicals included by the formula:

VI. ~13 (C) -R13-wherein R ls a divalent aromatic radical haviny from 6-13 carbon atoms selected from hydrocarbon radicals and halogenated hydrocarbon radicals, and G is a divalent organo radical selected from:

~l 13 ~14 z 2z ~ C , -IS~ O-, and -Si-30o l14 6~

where g is 0 or 1, z is an integer having a value of from 1-5 inclusive, and R14 is a monovalent hydrocarbon radical selected from methyl, phenyl, etc.
Illustrative of a compound falling within the scope of Formula V is one wherein R12 is phenylene and Rll iS

Such a compound is marketed by the General Electric Company under the tradename Ultem.
In the practice of the instant invention the aromatic polyester-carbonates are admixed with at least one polymer represented by Formula III, Formula LV, or Formula V to form the novel compositions of the present invention. The instant compositions can contain, in addition to the aromatic polyester-carbonate, only one polymer o~ Formula III, onlv one polymer of Formula IV, or only one polymer of Formula V; or they may contain a mixture of two or more polymers. Thus for example, the instant composition can contain (a) an aromatic polyester-carbonate, and (b) a polyamide of Formula III and a polyamideimide of Formula IV; (a) an aromatic polyester-carbonate, and (b) a polyimide of Formula V;
(a) a polyester-carbonate , and (b) two different polyi-mides of Formula V; or (a) an aromatic polyester-carbonate and (b) a polyamide of Formula III and a polyimide of Formula V and a polyamideimide of Formula IV.
Generally, the instant compositions contain from about 1 part by weight of the polyester-carbonate to 99 parts by weight of at least one compound of Formulae 3~8~
III, IV or V to 99 parts by weight of the axomatic polyester carbonate to l part by weight of at leas-t one compound of Formulae III, IV, or V. Preferably the ratio in parts by weight of the aromatic polyester-carbonate to the polymer selected from the group consisting of polyamides, polyimides, polyamideimides, or mixtures thereof ranges from 30:70 to 70:30, and more preferably from about 40:60 to 60:40.
The compositions of the instant invention may also optionally contain the commonly known and used additives such as antioxidants, antistatic agents, mold release agents, colorants, impact modifiers, ultra-violet radiation absorbers, plasticizers, fillers such as glass, talc, CaSO4, mica, carbon fibers, mineral clay, etc., color stabilizers, hydrolytic stabilizers, and flame retardan-ts such as, for example, those described in U.SO Patents 3,915,926 to Allan D. Wambach issued on October 28, 1975; and 4,197,232 to Charles A. Bialous et al, issued on April 8, 1980.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The following examples are set forth to further illustrate the present invention and are not to be construed as limiting the invention thereto. Unless otherwise specified, where parts or percents are mentioned, they are parts or percents by weight.

This example illustrates an aromatic polyester-carbonate resin which is not blended with any of -the aforedescribed polymers. Thus this example illustrates a composition falling outside the scope of the instant invention.

To a ten gallon reactor vessel there are added 8 liters of methylene chloride, 6 liters of water, 1,906 grams (8.36 moles) of bisphenol A, 20 milliliters of triethylamine, 4 grams of sodium gluconate, and 65 grams of p-tertiary butylphenol molecular weight regulator.
At a pH of between about 9-10.5 1,089.6 grams (5.37 moles) of a mixture of 15% by weight of isophthaloyl dichloride and 85% by weight of terephthaloyl dichloride in 2 liters of methylene chloride are added over a 10 minu-te interval while controlling the pH at about 9-10. 5 with 35% aqueous caus-tic. After the addition oE the diacid chloride misture phosgene is added at a rate of 36 grams per minute for 12 minutes while controlling the pH at about 10-11 with 35% aqueous caustic. The polymer mixture is diluted with 5 liters of methylene chloride and the brine phase is separated by centrifuge. The resulting polymer phase is washed with aqueous acid and water and is then recovered by high pressure steam precipitation to yield a white powder having an Intrinsic Viscosity of 0. 5 dl/g 20 in methylene chloride at 25C~ To this resin powder is added a minor amount (about 0.1 parts by weight per hundred parts by weight of resin) of a stabilizer mixture con-taining a phosphite color stabilizer and an epoxy s-tabilizer. This resin product is then fed to an extruder operating at a temperature of about 600 F to extrude the resin into strands and the extruded stands are chopped into pellets. The pellets are then injection molded at about 650F into test samples measuring abou-t 2-1/2" x 1/" x 1/8".

EXA~PLE 2 This example illustrates a composition of the present invention which contains a blend of an aromatic 6~ 8CL-3558 polyester-carbonate and a poletherimide.
An aromatic polyester-carbonate resin is prepared substantially in accordance with the procedure of Example 1. The powdered polyester-carbonate resin is mi~ed, in a 50:50 ratio by weight, with a polyetheri-mide resin represented by formula V wherein R12 is a phenylene radical and R 1 is the ~ IC
radical. This resin blend is then fed to an extruder operating at a temperature of about 650F to extrude the resin into strands and the extruded strands are chopped into pellets. The pellets are then injection molded at about 650F into test samples measuring about 2-1/2" x 1/2" x 1/8".
Various physical properties of the test samples obtained in Examples 1 and 2 were determined according to the following test procedures;
Heat Distortion Temperature Under Load (DTUL) of the molded samples was determined according to ASTM
D-647;
Notched Izod (NI) impact on the 1/8" thick molded samples was determined according to ASTM D-256;
Flexural Yield (FY) and Flexural Modulus (FM) were determined according to ASTM D-790;
Flame Retardancy (FR) of the molded samples was determined by subjecting the sample (5 samples for each Example) to the test procedures set Eorth in Underwriters' Laboratories, Inc. Bulletin UL-94, Burning Test for Classifying Materials. In accordance with this test procedure, materials so investigated ~ S 8CL-3558 are rated either V-O, V-l, or V-II based on the results of 5 specimens~ The criteria for each V(for ver-tical) rating per UL-94 is briefly as follows:
"V-O": Average flaming and/or glowing after removal of the igniting flame shall not exceed 5 seconds and none of the specimens shall drip flaming particles which ignite absorbent cotton.
"V-I": Average flaming and/or glowing after removal of the igniting flame shall not exceed 25 seconds and the glowing does not travel vertically for more than 1/8" of the specimen after flaming ceases and glowing is incapable of igniting absorbent cotton.
"V~ Average flaming and/or glowing after removal of the igniting flame shall not exceed 25 seconds and the specimens drip flaming particles which ignite absorbent cotton.
In addition, a test bar which continues to burn for more than 25 seconds after removal of the igniting flame is classified, not by UL-94 but by the standard of the present invention, as "burns". Further, UL-94 requires that all test bars in each test group must meet the V--type rating to achieve that particular classification.
Otherwise, the 5 bars receive the rating of the worst single bar.
The results of these tests are set for-th in Table I~

~6~ 8CL-3558 Example 1 _ mple _ (FY) in p.s.i. 14,000 17,700 (EM) in p.s.i. 310,0Q0 389,000 (DTUL) at 264 p.s.i., F 325 340 (NI) ft.lb./in. 6.0 2.0 (FR) V-II y-o In formulating the compositions of the instant invention the resins are admixed together and mixed or blended together by generally mechanical means such as stirring, shaking, blending in a mechanical blender, etc.
As seen from the data in Table I, the resin blends of the instant invention, Example 2, have a higher heat distortion temperature, higher flexural yield and higher flexural modulus than the unblended aromatic polyester-carbonate, Example 1. Additionally~ the compositions of the present invention are more flame retardant than the unblended aromatic polyester-carbonate.
~ t will thus be seen that the objects set forth above among those made apparent from the preceding description, are efficiently attained, and since certain changes may be made in carrying out the above process and the compositions set forth without departing from the scope of the invention, it is intended that all matters contained in the above description shall be interpreted as illustrative and not in a limiting sense.

- 17 ~

Claims (15)

The embodiments of the invention in which an exclu-sive property or privilege is claimed are defined as follows:

1. A thermoplastic composition comprising in admixture (a) an aromatic polyester-carbonate and (b) an aromatic polyester-carbonate heat distortion improving effective amount of at least one polymer selected from the group consisting of (i) aromatic polyamide of the formula wherein R3 and R5 are independently selected from halogen, alkyl of one to twelve carbon atoms, and substituted alkyl wherein the substituent is halogen or OR7 wherein R7 is an alkyl of one to ten carbon atoms;
R4 and R6 are independently selected from alkyl of one to twelve carbon atoms; hydrogen, aryl of six to eighteen carbon atoms, aralkyl of seven to eighteen carbon atoms;
a is from 10 to about 500;
b and c are independently selected from an integer of 0 to 4, (ii) aromatic polyamideimides, (iii) polyimides.

2. The composition of claim 1 wherein said aromatic polyester-carbonate is derived from a dihydric phenol, a carbonate precursor, and an aromatic dicarboxylic acid or a reactive derivative thereof.

3. The composition of claim 2, wherein said dihydric phenol is bisphenol-A.

4. The composition of claim 3, wherein said carbonate precursor is phosgene.

5. The composition of claim 4 wherein said aromatic dicarboxylic acid is selected from the group consisting of isophthalic acid, terephthalic acid, and mixtures thereof; and wherein the reactive derivative of said acid is selected from the group consisting of terephthaloyl dichloride, isophthaloyl dichloride, and mixtures thereof.

6. The composition of claim 5 wherein said aromatic polyester-carbonate is a copolymer resulting from the condensation of bisphenol-A with terephthaloyl dichloride, isophthaloyl dichloride and phosgene.

7. The composition of claim 1, wherein said polyamideimide is represented by the general formula wherein each R10 is independently selected from the group consisting of alkyl radicals, halogen radicals, and substituted alkyl radicals; R9 is selected from the group consisting of hydrogen, alkyl radicals, aryl radicals, aralkyl radicals and alkaryl radicals; R8 is selected from the group consisting of divalent aromatic organic radicals having from 6 to about 30 carbon atoms, alkylene radicals, alkylidene radicals, and cycloalkylene radicals; d has a value from about 10 to about 500; and e is an integer having a value from 0 to 3 inclusive.

8. The composition of claim 7, wherein said divalent aromatic organic radicals are selected from the group consisting of divalent aromatic hydrocarbon radicals and divalent halogenated aromatic hydrocarbon radicals.

9. The composition of claim 1, wherein said polyimides are polyetherimides.

10. The composition of claim 9, wherein said polyetherimides are represented by the general formula wherein f has a value from about 10 to about 500; R12 is selected from the group consisting of divalent aliphatic hydrocarbon radicals, divalent aromatic hydrocarbon radical, and divalent cycloaliphatic hydrocarbon radicals; and R11 is a divalent aromatic organic radical having from 6 to 30 carbon atoms.

11. The composition of claim 10, wherein R11 is selected from the group consisting aromatic hydrocarbon radicals; halogenated aromatic hydrocarbon radicals; and radicals included by the formula:
- R13 - (G)g - R13 wherein R13 is a divalent aromatic radical having from 6-13 carbon atoms selected from hydrocarbon radicals and halogenated hydrocarbon radicals, and G is a divalent organo radical selected from where g is zero or one, z is an integer having a value from 1 to 5, and R14 is a monovalent alkyl, aryl, alkaryl or aralkyl radical.

12. The composition of claim 11, wherein R11 is the radical.

13. The composition of claim 12, wherein R12 is a phenylene radical.

14. The composition of claim 13 wherein the aromatic polyester-carbonate is a copolymer resulting from the condensation of bisphenol-A with terephthaloyl dichloride, isophthaloyl dichloride and phosgene.

15. The composition of claim 1 which contains from about 30 to about 70 parts by weight of (a) and from about 70 to 30 parts by weight of (b) as measured by the total parts of (a) and (b).