CA1230696A - Polyetherimide-polycarbonate blends - Google Patents

Abstract

POLYETHERIMIDE-POLYCARBONATE BLENDS
Abstract of the Disclosure Disclosed are blends of (a) a polyetherimide and (b) a thermoplastic polycarbonate useful as films, moulding compounds and coatings. The blends exhibit a higher heat distortion temperature and an improved flexural strength and tensile strength over the polycarbonate component alone and have a higher impact strength than that associated with the polyetherimide component of the blends. In addition, the blends may exhibit good flame resistance.

Description

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POLYETHERIMIDE-POLYCARBONATE BLENDS
This invention relates to a class of blends containing a polyetherimide and a thermoplastic polycarbonate. The blends exhibit a higher heat distortion temperature, an improved floral strength and tensile strength over the polycarbonate component along and have a higher impact strength than that associated with the polyetherimide component of the blends. In addition, the blends may exhibit good flame resistance.
Thea blends of the invention include a polyetherimide of the formula:
O O

_ - N \ A - O - Z - A / N - R - I__ I I
O O a where a represents a whole number in excess o- 1, e.g., 10 to 10,000 or more, the group -O-A is selected from:
15 f ~f~30-~.~

I. .....

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R' being hydrogen, lower alkyd or lower alkoxy, preferably the polye~herimide includes the latter -O-A' group where R' is hydrogen such that the polyetherimide is of the formula:
_ O O
11 if - - N O - Z - O N - R- _ O O a and the diva lent bonds of the -O-Z-O- radical are in the 3,3'; 3,4'; 4,3' or the 4,4' position; Z is a member of the class consisting of (1) and SHEA
H3C SHEA H3C r By C~3 H3C C~13 H3C By By SHEA
By r - C(CH3)~
By By

(2) diva lent organic radicals of the general formula:

(q {I}

3~9~
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where X is a member selected from the class consisting of diva lent radicals of the formulas, Q O
-Sue -, -C-, -S-, -O- and -S-where q is 0 or 1, y is a whole number from 1 to 5; and R
is a diva lent organic radical selected from the class consisting of (1) aromatic hydrocarbon radicals having from 6-20 carbon atoms and halogenated derivatives thereof, (2) alkaline radicals and cycloalkylene radicals having -from 2-20 carbon atoms, C(2-8) alkaline terminated polyp diorganosiloxane, and (3) diva lent radicals included byte formula Q -where Q is a member selected from the class consisting of O
-O-, I -If-, -S- and Ox 2x where x is a whole number from 1 to 5 inclusive.
Particularly preferred polyetherimides for the purposes of the present invention include those where -OWE and Z
respectively are:
clue O and I }
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and R is selected from:

SHEA o The polyetherimides where R is metaphenylene are most preferred.
Polycarbonates for use in the blends ox the invention can be generally defined as high molecular weight, thermoplastic, aromatic polymers and includes homopoly carbonates and copolycarbonates and mixtures thereof which have average molecular weights of about 8,000 to more than 20,000, preferably of about 20,000 to 80,000 and an IVY.
of 0.40 to 1.0 dug as measured in ethylene chloride at 25C. These polycarbonates are derived from dihydric phenols and carbonate precursors and generally speaking, contain recurring structural units of the formula:
_ O-- - O YO-YO C--_ where Y is a diva lent aromatic radical of the dihydric phenol employed in the polycarbonate producing reaction.
Suitable di.hydric phenols for producing polycarbonates include the dihydric phenols such as, or example, 2,2~bis(4-hydroxyphenol)propane, bist4-hydroxy-phenol) methane, 2,2-bis(4-hydroxy-3~methylphenyl~propane,

4,~-bis~4-hydro~yphenyl)hep-tane, twitter-chloro-4,4'-dihydroxyphenol)propane, 2,2-(3,5,3',5'-tetrabromo-4,4'-dihydroxyphenyl)propane, and (3,3'-dichloro-4,4'-dihydroxydiphenyl)methane. Other dihydric phenols which are also suitable for use in the preparation owe the above polycarbonates are disclosed in So Patent Nos. 2,999,835, issued September 12, 1961 to Goldberg, 3,038,36S, issued June 12, 1~62 to Peterson, 3,334,154, issued ~uyust 1, 1967 to Kim and 4,131,575, issued December 2G~ 1978 to Adelmann et at.

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It is of course possible to employ two or more different dihydric phenols or a copolymer of a dihydric phenol with a glycol or with hydroxy or acid terminated polyester, or with a dibasic acid in the event a carbonate copolymer or inter polymer rather than a homopolymer is desired for use in the preparation of the blends of the invention. Blends of any of the above materials can also be employed to provide the aromatic polycarbonate. In addition, branched polycarbonates such as are described in US. Patent No. ~,001,1~4, issued January 4, 1977 to Mueller et at, can also be utilized in the practice of this invention, as can blends of a linear polycarbonate and a branched polycarbonate.
The carbonate precursor employed can be either a carbonyl halide, a carbonate ester or a haloform ate.
The carbonyl halides which can be employed are carbonyl bromide, carbonyl chloride and mixtures thereof. Typical of the carbonate esters which can be employed are diphenyl carbonate, a di-(halophenyl)carbonate such as di-(chlorophenyl)carbonate, di-(bromophenyl)carbonate, di-(trichlorophenyl)carbonate, di-(tribromophenyl) carbonate,etc., di-(alkylphenyl)carbonate such as di-(tolyl)carbonate, etc., di-(napthyl)carbonate, di-(chloronaphthyl)carbonate, etc., or mixtures thereof.
The suitable halofo:rmates include bis-haloformates of dihydric phenols (bischloroformates of hydro~uinone, eta) or glycols (bishaloformates of ethylene luckily, neopentyl luckily, polyethylene glycol, etc.). While other carbonate precursors will occur to -those skilled in -the art, carbonyl chloride, also known as phosgene, is preferred.
Also included in the polycarbonates are the polymeric materials derived from a dihydric phenol, a dicarbo~ylic acid and carbonic acid. These are disclosed in US. Patent No. 3,169,121, issued February 9, 1965 to Goldberg.

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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 androids) of the formula O O

\ I Z / O
If if O O

where Z is as defined hereinabove with an organic Damon of the formula l~l2N - R - NH2 where R is as defined herein before.
Aromatic bis(ether androids 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)be~zene dianhydride;
4,4'-bis(2,3-dicarboxyphenoxy)diphenyl sulfide dianhyclride;
1,4-bis[2,3-dicarboxyphenoxy)benzene dianhydride; Boyce (2,3-dicarboxyphenoxy)benzophenone dianhydride, Boyce (2,3-dicarboxyphenoxy~diphenyl cellophane dianhydride; etc., 2,2-bis[4-(3,4-dicarboxyphenoxy)phenyllpropane dianhydride;
4,4'-bls(3,4-dicarboxyphenoxy)diphenyl ether dianhydride;
4,4'-bis(3,4~dicarboxypheno~y)di.phenyl sulfide dianhydride;
1,3-bis(3,4-dicarboxyphenoxy)benzene dianhydri.de;
1,4-bis(3,4-dicarboxyphenoxy)benzene dianhydride;
4,4'-bis(3,4-dicarboxypherloxy)benzc)phenone dianhydride;
4-(2,3-clicarboxyphenoxy)-4'-(3,4-clicarboxyphenoxy~diphenyl-2,2-propane dianhydride; etc., all mixtures of such dianhydrides~

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In addition, aromatic bis(ether androids also included by the above formula are shown by Kitten, MUM.;
Florinski, US sessonov, Mix Rudakov~ ASP. (Institute of Heteroorganic Compounds, Academy of Sciences r U . S . S . R . ), U.S.S.R. 257,010, Nov. 11, 1969, Apply May 3, 1967. Also, dianhydrides are shown by MUM. Kitten, US Florinski, Oh Org. Kin, I, 774 (1968).
Organic dominoes of the above formula include, for example, m-phenylenediamine, p-phenylenediamine, 4,4'-diaminodiphenyl propane, 4,4'-diaminodiphenylmethane, benzidine, 4,4'-dlaminodiphenyl sulfide, 4,4'-diaminodiphenyl cellophane, 4,4'-diaminodiphenyl ether, 1,5-diaminoaphthalene, 3,3'-dimethylbenzidine, 3,3'-dimethoxybenzidine, Boyce -amino-t-butyl)toluene, bis(p-~-amino-t-butylphenyl)ether, wisp -methyl-o-aminophenyl)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-Damon, 4,4-dimethylheptamethylenediamlne, 2,11-dodecanediamine, 2,2-dimethylpropylenediamine, octamethylenediamine, 3-methoxyhexamethylenediamine, 2,5-dimethylhexamethylenediamine, 2,5-dimethylheptamethylenediamine, 3-methylheptamethylenediamine,

5-methylnonamethylenediamine, 1,4-cyclohexanediamine, 1,12-octadecanediamine, bis(3-aminopropyl)sulfide, N-methyl-bis(3-aminopropyl)amine, hexamethylenediamine, heptamethylenediamine, nonamethylenediamine, decamethylenediamine, bis(3-aminopropyl) tetramethyldisiloxane, bis(4-aminobutyl)tetramethyl disiloxane, and the like, and mixtures of such dominoes.
In general, the reactions can be advantageously carried out employing well-known solvents, eye., o-dichlorobenzene, m-cresol/toluene, etc., in which to effect interaction between the dianhydrides and the dominoes, a-t temperatures of from about 100 to about I
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250C. Alternatively, the polyetherimides can be prepared by melt polymerization of any of the aforementioned dianhydrides with any of the aforementioned Damon compounds while heating the mixture of the ingredients at elevated temperatures with concurrent intermixing.
Generally, melt polymerization temperatures between about 200 to 400C. and preferably 230 to 3Q0C. can be employed. Any order of addition of chain stopper ordinarily employed in melt polymerization 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 Damon and dianhydride are employed for high molecular weight polyetherimides, however, in certain instances, a slight molar excess (about 1 to 5 mow percent) of Damon can be employed resulting in the production of polye-therimides having terminal amine groups. Generally, useful polyetherimides have an intrinsic viscosity [I ] greater 20 than 0.2 deciliters per gram, preferably 0.35 to 0.60 or 0.7 deciliters per gram or even higher when measured in m-cresol a-t 25C.
Included among the many methods of making the polye-therimides are those disclosed in US. Patent Nos.
25 3,847,~67, issued November 12, 1974 to Heath et at, 3,847,869, issued November 12, 1974 to Williams, 3,850,885, issued November 26, 1974 to Takeoshi et at, 3,852,242, issued December 3, 1974 to White and 3,855,178, issued December 17, 1974 to White.
The polycarbonates of the subject blends can be manufactured by known processes, such as, for example, by reacting a dihydric phenol with a carbonate precursor such as diphenyl carbonate or phosgene in accordance with methods set forth in -the above-cited literature and So 35 Patent Nos. 4,018,750, issued April 19, 1977 to Owns and ~,123,436, issued October 31, 1978 to lullaby et at, or by -transesterification processes such as are disclosed do I 36 KIWI
_~_ in US. Patent No. 3,153,008, issued October 13, 196~ to Fox, as well as other processes known to those skilled in the art.
The aromatic polycarbonates are typically prepared by employing a molecular weight regulator, an acid acceptor and a catalyst. The molecular weight regulators which can be employed include phenol, cyclohexanol, methanol, para-tertiary-bu-tyl-phenol, etc.
Preferably, phenol is employed as the molecular weight regulator.
The acid acceptor can be either an organic or an inorganic acid acceptor. A suitable organic acid acceptor is a tertiary amine and includes such materials as pardon, triethylamine, dimethylaniline, tributylamine, etc. The inorganic acid acceptor can be one which can be either a hydroxide, a carbonate, a bicarbonate, or a phosphate ox an alkali or alkali earth metal.
The catalysts which can be employed are those that typically aid the polymerization of the monomer with phosgene. Suitable catalysts include tertiary amine such as triethylamine, tripropylamine, N,N-dimethylaniline, ~uaternary ammonium compounds, such as, for example, tetraethylammonium bromide, Seattle triethyl ammonium bromide, tetra-n-heptylammonium iodide, tetra-n-propyl ammonium bromide, te-tramethyl-ammonium chloride, -twitter-methyl ammonium hydroxide, tetra-n-butyl ammonium iodide, benzyltrimethyl ammonium chloride and ~uaternary pros-phoneme compounds such as, for example, n-butyltriphenyl phosphonium bromide and methyltriphenyl phosphonium bromide.
Also included are branched polycarbonates wherein a polyfunctional aromatic compound is reacted with the monomer and carbonate precursor to provide a thermos plastic randomly branched polycarbonate. The polyp functional aromatic compounds contain at least threafunctional groups which are carboxyl, carbolic android, I
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halo:Eormyl, or mixtures thereof. Illustrative polyp functional aromatic compounds which can be employed include trimellitic android, trimellitic acid, trimellityl trichloride, 4-chloroformyl phthalic android, pyromellitic acid, pyromellitic dianhydride, mellitic acid, mellitic android, trimesic acid, buoyancy-phenonetetracarboxylic acid, benzophenonetetracarboxylic android, and the like. The preferred polyfunctional aromatic compounds are trimellitic android and trimellitic acid or their acid halide derivatives.
In accordance with the present invention;
blends of a polyetherimide and a polycarbonate are generally obtainable in all proportions of the polymers relative to each other. Thus, the polyetherimide and carbonate components of the blend may be mixed in weight ratios of l:00 to 99:1 relative to each other and such a range of mixtures may be combined with the thermoplastic component in weight ratios of 1:39 to 99:1. It may be generally desirable to include a minimum amount of, for example, about 2%, of each of the components to achieve the desired properties for the blend. my controlling the proportions of the components of the blend relative to each other, blends having certain predetermined useful properties which are improved over those of certain components alone may be readily obtained. In general, blends of the subject invention may exhibit, depending on -the blend ratio of the components, one or more of the properties of high tensile and/or flexural strength, good impact strength and good high heat distortion -temperature.
It is contemplated that -the blends of the present invention may also include other additive materials such as fillers, stabilizers, plasticizers, flexibilizers, surfactant agents, pigments, dyes, reinforcements, lame retardants and delineates in conventional amounts. It is also contemplated that the blends of the invention may KIWI

include two or more polyetherimides in combination with one or more polycarbonates or two or more polycarbonates in combination with one or more polvetherimides~
Methods for forming blends of the present invention may vary considerably. Prior art blending techniques are generally satisfactory. A preferred method comprises blending the polymers and additives such as reinforcements in powder, granular or fulminates form, extruding the blend, and chopping the extradite into pellets suitable for molding by means conventionally used to mold normally solid thermoplastic compositions.
The subject blends 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 work loading at elevated temperatures for linkage 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 wised in laminated structures where films or solutions of the blond 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 ox the resinous binder to yield cohesive laminated structures. Films made -from the subject blends can also serve in printed circuit applications.

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Alternatively, solutions of the blends herein described can be coated on electrical conductors such as copper, aluminum, eye., and thereafter the coated conductor can be heated at elevated temperatures to remove the solvent and to effect curing of the resinous composition thereon. If desired, an additional overcoat may be applied to such insulated conductors including the use of polymeric coatings, such as polyamides, polyesters, silicones, polyvinyl formal resins, epoxy resins, polyamides, polytetrafluoroethylene, 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 polymer blends of the invention by ineorporatinc3 such fillers as asbestos, glass fibers, -talon quartz, powder, finely divided carbon, and silica into the blends prior to molding. Shaped articles may be molded under heat, or under heat and pressure, in accordance with -the practices well-known in the art.
The ~ollowinc3 examples illustrate specific polyetherimide-polycarbonate 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 end percentacJes are by weight unless otherwise specified.
EXIT I
_ Polyetherimide-polycarbonate blends accordinc3 to the invention were prepared and tested for various mechanical properties.
The polyetherimide used in preparing the blend was of the structural formula:

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O O

-N \ I

SHEA

a and the polycarbonate was a commercial polycarbonate sold under the trademark Lean by the General Electric Company, Pittsfield, Massachusetts. The polyetherimide alone had the physical properties set forth in Table I.
The two polymers were melt blended in a weight ratio of about 95 parts polyetherimide to about 5 parts polycarbonate and the blend viscosity measured on an Instron capillary remoter at about 300C and a shear rate of about one sec. . UponsOlidification of the blend, various physical properties of thy blend such as glass transition temperature (Tug), oxygen index (OIL, tensile strength and elongation were measured. The results of these measurements are also set forth in Table I.
SAMPLE II
The procedure of Example I was repeated with the exception that about go parts of polyetherimide and about 10 parts of polycarbonate were formulated to produce the blend according to the invention. The properties of the I blend are set forth in Table I.
EXAMPLE III
The procedure of Example I was repeated with the exception that about 85 parts of polyetherimide and about 15 parts of polycarbonate, were formulated to produce -the blend according to the invention. The properties of the blend are set forth in Table I.

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O I
'I _ .
owe --CO o o o Jo o h -I
c: O O O
Q o o o o Jo I
Us Jo Jo a) _ .
H
a a Jo H
En X Jo co a O

a) h O or I _ C.) r I r-l r Us Al h O
pa u, q) _, co ED Lo LO
O O O O
I
___ owe O 11~ 0 1~1 I O I- o a I
I
I
3 0 _ r-t H
I
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From the data set forth in the above table concerning various blends according to the present invention, it is apparent that -the blends are not totally compatible since each polymer retains its own glass transition temperature. however, the blends do exhibit a good appearance and are suitable for a variety of applications.
EXAMPLE IV
A polyetherimide-polycarbonate blend according to the invention was prepared, the blend then molded into test specimens and the specimens tested for various physical properties.
The polyetherimide for the blend was prepared from the reaction product of essentially equimolar amounts of 2,2-bis[4-(3,~-dicarboxyphenoxy)phenyl]propane dianhydride and m-phenylene Damon 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. A test specimen injection molded from the pellets had the physical properties set forth in Table II. The polycarbonat~ used in the blend was a bisphenol A type polycarbonate sold under -the trademark LEAN 141 by the General Electric Company, Pittsfield, Massachusetts. This polycarbonate, prepared by reacting 2,2-bis(4-hydroxyphenyl)propane, (bisphenol-~) and phosgene in the presence of an acid acceptor and a molecular weight regulator, has an intrinsic viscosity of about 0.57 dug Various physical properties of this polycarbonate are set forth in Table II.
The polymers were mixed in a weight ratio of about 10 parts polyetherimide and about 90 parts polyp carbonate and then extruded in a 28mm Werner & Pfleiderer extrude havincJ a temperature profile varyinc3 from about 570 to ~15 F. The resulting extradite was commented into pellets and the pellets injection molded into test specimens at a temperature of about 550 F. Impact ~3~6~3Çi KIWI

strength of the specimen was measured according to the notched and unwished Issued test and the Gardner impact test and the results are set forth in Tale II. The heat distortion temperature, tensile properties and flexural properties of the blend were also measured and are set forth in Table II.
SAMPLE V
The procedure of Example IV was repeated with the exception that about 30 parts of polyetherimide and about 70 parts of polycarbonate, were formulated to produce the blend according to the invention and the blend was injection molded at a temperature of about 575 to 590 F.
to produce test specimens. The results of the notched and unwished Issued and Gardner impact tests as well as the heat distortion temperature tensile properties and flexural properties for the blend are detailed in Table II.
EXAMPLES VI
The procedure of Example IV was repeated with the 2Q exception that about 50 parts of polyetherimide and about 50 parts of polycarbonate, were formulated to produce the blend according to the invention and the blend was injection molded at about 575 to 620F. to produce test specimens. The results of the notched and unwished Issued and Gardner impact jests, as well as the heat distortion temperature, flexural properties and molding pressure for the blend are coven in Table II.
EXAMPLE VII
The procedure of Example IV was repeated with the exception that about 70 parts of polyetherimide, and about 30 parts of polycarbonate were formulated to produce the blend accordincJ to the invention and the blend was extruded at about 620 to 650F and injection molded at about 650 F.
to produce test specimens. The results of the notched and unwished Issued and Gardner impact tests, as well as the heat distortion -temperature, tensile properties and flexural properties for the blend are detailed in Table II.

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Example VIII
The procedure of Example VII was repeated with the exception that about 90 parts owe polyetherimide, and about lo parts of polycarbonate were formulated to produce the blend according to the invention. The results of the notched and unwished Issued and Grander impact tests, as well as the heat distortion, tensile properties and flexural properties for the blend are detailed in Table II.

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During the generation of the above data, several observations concerning the blends of the invention were made. One, the blends had a lower melt viscosity than the polyetherimide component alone which thereby allows the blends to be processed at a lower temperature.
Second, the blends appeared to be one phase systems with no delamination or phase separation in the molded specimens although the specimens were actually a two-phase system as evidenced by two glass transition temperatures. Third, all the specimens were generally opaque in appearance. Fourth, some of the unwished Issued values are not absolute values since the test specimens twisted or bent out of the path of the hammer upon impact rather than breaking and thus these values only represent impact strength values relative to the other specimens tested.
As to the physical properties of -the blends, it is apparent from the above data that the heat distortion temperature and flexural and tensile properties of all the blends, particularly those containing in excess of about 50% polyetherimide were all improved over the polycarbonate component alone. The unwished impact strength is generally improved over that of the polyp e-therimide component alone and the notched Issued and Gardner impact strengths are particularly improved at a blend concentration of about 30% or more polycarbonate.
EXAMPLE IX
A polyetherimide polyester carbonate blond according to the invention was prepared, -the blend molded into -test specimens, and the specimens tested for physical properties and for flame resistance The polyetherimide for the blend was prepared from -the reaction product of essentially equimolar amounts of 2,2-bis[~-(3,~-dicarbo~ypheno~y)phenyl]propane dianhydride and m-phenylene Damon. A test specimen injection molded from the pGlyetherimide had the physical properties and the flame characteristics as set forth in Tables III and It.

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The polyester carbonate was derived from bisphenol A, isophthalic acid and a carbonate was derived from bisphenol A, mole ratio isophthalic acid to carbonate precursor. The polyester carbonate alone had the physical properties and the flame characteristics as set forth in Tables III and IV.
The two polymers were mixed in a weight ratio of about 25 parts polyetherimide and 75 parts polyester carbonate and extruded in a Werner & Pfleiderer extrude lo having a temperature of about 680F. The resulting extradite was commented into pellets and the pellets injection molded into test specimens at a temperature ox about 680F. Impact strength of a specimen was measured according to the notched Issued test, ASTM D-256, and the results are set forth in Table III. The heat distortion temperature, flexural strength and flexural modulus of the blend were also measured and are given in Table III. In addition, the flame resistance characteristics of the blend are set forth in Table IV
as determined by the test set forth in Bulletin No. 94 of the Underwriters Laboratory (UL-94).
EXAMPLE X
The procedure of Example IX was repeated with the exception that about 50 parts of polyetherimide and about 50 parts of polyester carbonate were formulated to produce the lend according to the invention. The results of the notched Issued impact test as well as the heat distortion -temperature, flexural strength, and flexural modulus for the blend are detailed in Table III.
The flame resistance characteristics of the blend are set forth in Table IV.

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En' if a 8~U-3290 It is contemplated that the substitution of other polyetherimi.des or polycarbonates for the components of the blends of the above examples may result in the formulation of polymer blends having one or more improved characteristics such as impact strength, flame resistance, tensile properties, flexural properties and high heat distortion -temperature over one or more of the polymer components taken alone.
While the present invention has been described with reference to particular embodiments thereof, it will be understood -that numerous modifications may be made by those skilled in the art without actually departing from the spirit and scope of the invention as defined in the appended claims.

Claims (7)

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

1. A composition consisting essentially of a blend of (a) a polycarbonate and (b) a polyetherimide, wherein the polycarbonate consists of recurring structural units of the formula:
wherein Y is divalent aromatic radical of a dihydric phenol selected from the group consisting of 2,2-bis(4-hydroxyphenyl)propane, bis(4-hydroxyphenyl)methane, 2,2-bis(4-hydroxy-3-methylphenyl)propane, 4,4-bis(4-hydroxyphenyl)heptane, 2,2-(3,5,3',5'-tetrachloro-4,4'-dihydroxyphenyl)propane, 2,2-(3,5,3',5'-tetrabromo-4,4'-dihydroxyphenyl)propane, and (3,3'-dichloro-4,4'-dihydroxyphenyl)methane.
2. A composition in accordance with claim 1, wherein the polyetherimide has the formula:
where a represents a whole number in excess of 1, the group is selected from:
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Claim 2 continued:
R' being hydrogen, lower alkyl or lower alkoxy, and Z is a member of the class consisting of (1) and (2) divalent organic radicals of the general formula:
where X is a member selected from the class consisting of divalent radicals of the formulas:
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 where Q is a member selected from the class consisting of where x is a whole number from 1 to 5 inclusive.

3. A composition in accordance with claim 2 wherein the polyetherimide is of the formula and the divalent bonds of the -O-Z-O- radical are in the 3,3'; 3,4'; 4,3' or 4,4' position.

4. A composition in accordance with claim 3, wherein Z is and R is selected from:

5. A composition in according with claim 4, wherein the polyetherimide is of the formula:

6. A composition in accordance with claim 1 wherein the dihydric phenol is bisphenol A and wherein the polycarbonate is derived from carbonyl chloride.

7. A composition in accordance with claim 1 wherein the dihydric phenol is bisphenol A and wherein the polycarbonate is derived from diphenyl carbonate.