CA1155999A - Particulated polyetherimide and method for making - Google Patents

Abstract

Abstract of the Disclosure Finely divided polyetherimide is provided which can be used in a variety of applications. These oligomers, in the form of fine powders, are particularly useful for coating wire by a powder coating technique.

Description

` ~5~9~ RD-8287 PARTICULATED POLYETHERIMIDE
AND METHOD FOR MAKING

Cross-References to Related Appllcations Reference is made to U.S. patent 4,098,800 .issued July 4, 1978 to Banucci et al and -titled "Process For Preparing Polyetheramide Acids", U.S. patent 4,281,100 issued July 28, 1981 to Tohru Takekoshi and titled "Injection-Moldable Polyetherimide Oligomers and Method for Making", and Canadian application Serial No. 353,461 filed June 5, 1980 by Tohru Takekoshi and titled "A Method of Making a Polyetherimide Prepolymer", where the above-mentioned patents and application are assigned to the present assignee.
Background of the Invention As shown by the above-mentioned U.S. patent 4,098,800, particulated oligomeric polyetheramide acids can be made by effecting reaction between (a) an aromatic bis(ether anhydride) of the formula 0 C` "
(1) O~ ~}o~z-o--~ \O, ~, and (b~ mixtures of one or more of the bis(ether anhydride)s with up to 30 mole percent benzophenone dianhydride of the general formula, ~3 :

5~9 O O
,. ..

(2) \ C ~ C ~ C /

O O
with at least one organic diamine of the general formula, ~3) H2N-R-NH2 , in an iner~ organic liquid selec~ed from the group consist-ing of (c) chlorinated hydrocarbon selected from the group consisting of methylene chloride, chloroform, 1,2-dichloro-; ethane, and m xtures thereof and (d) mixtures of said chlorin-ated hydrocarbon with up to 50% by weight of acetone to form oligomeric polyetheramide-acid which is substantially insoluble in said liquid, where ~ is a member selected from : CH3 CH\3 CH3 .

, and - ~ -: ~C 3 ~13 -, , ~ .
~: ~ and divalent organic radicals of the general formula, ;:
~X~

where X is a member selected rom the class consisting of .
divalent radicals of the formulas, O O
-CyH2y- , -C-, -S- , -O- and -S-, ~) : 2-~SSg~ P.D-8287 where y is an integer from 1 to 5, and R is a divalent organic radical selected from the class consisting of aromatic hydro carbon radicals having from 6 -to about 20 carbon atoms and halogenated derivatives thereof, alkylene radicals having from 2 to about 20 carbon atoms, cycloalkylene radicals having from

3 to about 20 carbon atoms, from C2 to about C8 alkylene term-inated polydiorganosiloxane and divalent radicals of the gen-eral formula, . ~ Q ~

where Q is a member selected from the class consisting of -O-, -S-, and -CXH2x-, where x is an integer from 1 to 5.
It has been found that the above-described particu-lated polyetheramideacids of Banucci et al are useful in various coating applications, for example, applications to : 15 aluminum or copper wire using fluid bed electrostati.c coating procedures. ~lowever, these electrostatically applied oligomeric powders can readily form films containing entrapped bubbles which xeduce the insulating characteristics of the polyether-imide coating. It has now been discovered that substantially ~bubble~free fil~s can be made by preheating the.partie-llated, substantially organic solvent-free polyetheramide acid , pre-ferably in an oxygen-free atmosphere and at a temperature in the range of 135C to 175C for a period of time sufficient to effect at least 70~ imidization of the organic solvent-free polyetheramide acld without causing a substantial degree of sintering or agglomeration of the polyetherimide powder. This result is quite surprising since the imidization of the par-ticulated polyetheramide acid occurs in the absence of an organic solvent.
Statement o the Invention There i5 provided by the present invention, particu-].ated, substantially urganic solvent-fre~ polyetherimide having at least 50 mol percent of imide radicals hased on the total mols of imide radicals and amide acid radicals and an average particle s.ize in the range of 0.5 to 70 microns, which is melt-able or sinterable at temperatures up to 225C and capable of being converted to a substantially bubble-~ree flexible film upon being hea~ed at a temperature in the range of from about 225C to 325C and in substance as high as 400C
The particulated polyetherimide of the present inven tion can be further characterized as being particulated organic solvent-free polyetheramide acid consisting essentially lS of chemicalLy combined am.ide acicl units of the formula, O O H
-N-C C-NR-

(4) ~ ~Z~ ~
HO-C C-OH
~ .. ..
O O
which has been heated at a temperature in the range of about 135C to 175C until the resulting particulated product con-sists essentially of about 70 mole percent of chemically com-20bined imide units of the formula, O o ,. ..

C ~ ~ NR-\ C C /
O O
wher~ Z and R a.re as previously defined, based on the total moles of chemically combined imide units and amide acid units without a substantial degree of sintering occuring.in the 91~ 9 polyethe~amideacid during the aforementioned heat -treatment where the polyetheramideacid i5 the product of reactlon of organic dianhydride and organic diamine utiliz~d in a mol ratio of 1 mol of organic dianhydride, per 1 to 1.5 mol of organic diamine, where the organic dianhydride is selected from the group consisting of (A) aromatic bis(ether anhydride)s of formula (1) and (B~ mixtures of 1 or more of said bis(etheranhy-dride~s with up to 30 mol percent of benzophenone dianhydride of formula (2), with at least one organic diamine of formula (3), where said polyetheramide acid reaction pxoduct has a number average molecular weight of below about 5000.
Aromatic bis(ether anhydride~s of formula (1) include, for example:
lS 2,2-bis[4-(3,4-dicarboxyphenoxy)phenyl]propane dianhydride;
4,4'-bis(3,4 dicarboxyphenoxy)diphenyl ether dianhydride;
4,4'-bis(3,4-dicarboxyphenoxy)diphenyl sulfide dianhydride;
4,4'-bis(3,4-dicarboxyphenoxy)benzophenone dianhydride;
4,~-bis(3,4-dicarboxyphenoxy)diphenyl sulfone 2,2-bis[4-(2,3~dicarboxyphenoxy)phenyl]propane dianhydride;
4,4'-bis(2,3-dicarboxyphenoxy)diphenyl ether dianhydride;
4,4'-bis~2,3-dicarboxyphenoxy)diphenyl sulfide 3~ dianhydride;
4,4'-bis(2,3-dicarboxyphenoxy~benzophenone dianhydri.de 4,4' bis(2,3~dicarboxyphenoxy)diphenyl sulfone dianhydride;
4-(2,3-dicarboxyphenoxy)-4'-(3,4-dicarboxyphenoxy)-diphenyl-2,2-propane dianhydride, ~559~9 RD-8287 and mixtures thereoE.
Aromatic bis(ether anhydride)s especially preferred herein are 2,2-bis[4-(3,4-dicarboxyphenoxy~phenyl~propane dianhydride, 2,2-bis[4~(2,3-dicarboxyphenoxy)-phenyl]propane dianhydride; 4-(2,3-dicarboxyphenoxy)-4'-(3,4-dicarboxyphenoxy) diphenyl-2,2-propane dianhydride; and mix~ures thereof.
Some of the aromatic bis(ether anhydride)s o for-mula (1) are shown in U.S. Patent No. 3,972,902 (Darrell Heath and Joseph Wirth). As described th~rein, the bis(ether anhydride)s can be prepared from the hydrolysis, followed by dehydration, of the reaction product of a nitro-substituted phenyl dinitrile wi~h a metal salt of a dihydric phenol com-pound in the presence of a dipolar aprotic solvent.
Additional aromatic bis(ether anhydride)s also included by formula (1) are shown by Koton, M M. Florinski, F.S. Bessonov, M.I. Rudakov, A.P. (Institute of Heteroorganic Compounds, Academy of Sciences, (U.S.S.R.), U.S.S.R. 257,010, Nov. 11, 1969, Appl. May 3, 1967, and by M. M. Koton, F.S.
Florinski, Zh. Org. Khin, 4 (S), 774 (1968).
The organic diamines of formula (3) include, for example:
o-phenyIenediamine, m-phenvlenediamine, p-phenylenediamine, 4,4' diaminodiphenylpropane, 4,4'-diaminodiphenylmet~ane (commonly named 4,4'-methylenedianiline), 4,4'-diaminodiphenyl sulfide (commonly named 4,4'-thiodianiline), 4,4' diaminodiphenyl ether (com~only named 4,4'-oxydianiline), ~ ~S5~9 1,5-diaminonaphthalene, 3,3'-dimethylbenzidine, 3,3'-dimethoxybenzidine, 2,4-bis(~-amino-t-butyl)toluene, bis(p~-amino-t-butyl3ether, bi~(p-~-me~hyl-o-aminopentyl)benzene, 1,3-diamino-4-isopropylbenzene, 1,2-bis(3-aminopropoxy)ethane, benzidine, m-xylylenediamine, p-xylylenediamine, : 2,4-diaminotoluene 2,6-diaminotoluene, bis(4-aminocyclohexyl)methane, 3-methylheptamethylenediamine, 4,4-dimethylheptamethylenediamine, : 2,11-dodecanediamine, : 2,2 dimethylpropylenediamine, octamethylenediamine, ;:20 ~ 3-methoxyhexamethylenediamine, 2,5-dimethylhexamethylenediamine, ~:~ : 2,5-dimethylheptamethylenediamine, : ~: 3-methylheptamethylenediamine, : ~ 5-methylnonamethylenediamine, 1,4-:cyclohexanediamine, 1,12-octadecanediamine, bis(3-aminopropyl)sulfide, N-me~hyl-bis(3-aminopropyl)amine, : :
hexamethylenediamine, heptame~hylenediamine, .

9 ~ .

nonamethylenediamine, decamethylenediamine, bis(3-aminopropyl)tetramethyldisiloxane, bis(4~aminobutyl)tetramethyldisilo~ane, and mixtures of such diamines.
Organic diamines preferred herein are 4,4' mathylene-dianiline, 4,4'-oxydianiline, metaphenylenediamine, and mixtures thereo~. -Benzophenone dianhydrides included by formula (2) include 3,3',4,4l-benzophenone tetracarboxylic acid dianhydride, 2,2',3,3'-ben~ophenone tetracarboxylic acid dianhydride, and mixtures thereof. The 3,3',4,4'-isomer is preferred and is referred to herein for simplici.ty as BTDA.
In the practice of the invention, particulated oligomeric polyetheramide acids or "polyamide acid'l consistins essentially of chemically combined ~lnits of formula (4), can be heated at tempe.ratures in the range of 135C to 175~C for a period of 1 hour or less to 24 hours or more, based on the nature of the polyetheramide acid.
As disclosed by sanucci et al, the polyamide acid can be made by using from about 1 to about 1.5 mo.le of organic diamine, p~r mole of organic dianhydrideO In general, the charackeristics of the polyamideacid, i.e., its ability to . be crosslinked for desirable wire coating characteristics, can be influenced by the amine content of the polyamide acid and the nature of the amine.
An alternative procedure for determini.ng whether heat treatment of the polyamide acid has been sufficient is to titrate the polyamide acid prior to heating and subsequent to the heat treatment~ which as previously deFined, is heatlng 11 ~55g9~

the polyamide acid at a temperature in the range of 135C to 1~5C without sintering the particulate. Preferably, heating is accomplished under a non-oxidizing atmosphere. which can be achieved by using an inert gas such as nitrogen, argon, etc.
Residual polyamide acid of less than about 30 mole percent is preferred, based on the total moles of polyamide acid originally titrated and can provide oligomer having desirable melt flow properties and convertible to bubble-free films.
The amine content, anhydride content and amide acid content of the oligomers prepared in the following examples were determined using the potentiometric titration procedures next described. Amine content was determined by dissolving a known amount (approximately 0.2 gram) of sample in 25cc of liquified phenol lapProximately 90 parts phenol and lO parts water) and thereafter titrating with approximately 0.l8N
methanesulfonic acid dissolved in a mixture of 150 parts by volume of methanol and 70 parts by volume of benzene. .~rLi~e- 7 acid and anhydride content were de~termined by dissolving a known amount (about 0.05 gram) of sample in a mixture of lcc water and 2cc N-methyl-2-pyrrolidone. After allowing one hour for hydrolysis of any anhydride present to dicarboxylic acid end groups, 25cc o~ pyridine was added and the sample was titrated with approximately 0.08N tetrabutylammonium hydroxide (TBAH) prepared by diluting lN methanolic TBAH with lO0/30 methanol benzene solution. (The two acid groups derived from the anhydride hydrolysis are stronger and weaker, respectively, than the amideacidi. If anhydride was present in the original unhydrolyzed sample, the stronger anhydride-derived carboxylic acid titrates irst with a rather poorly defined end-point (A).
The amide acid titrates next, with a well~defined end point (B).

9_ :~ ~5~9 The weaker anhydride derived carboxyli~ acid titrates last, as indicated by a well-defined end point (C) if no imide is present. In such instance, the anhydride content in the original sample is considered equivalent to the milliequivalents (meq) of base consumed from end-point B to end-point C. The amide acid in the sample is considered equivalent to total base consumed up to end-point B minus the anhydride content. If imide is present, the end-point for the weaker carboxylic acid is less well-defined because imide ring opening commences as soon as the weak acid has been neutralized. In this instance the choice of end point C is less well-defined and the values for the strong and weak anhydride-derived carboxylic acids are averaged to compute the anhydride content of the original sample. Oligomers prepared at a mole ratio of diamine to dianhydride greater than 1.0 will usually contain no anhy-dride end groups, and titration of the initial polyamide acid accordlng to the above procedure will give only oneend point B from which the milliequivalents of amide acid per gram of sample can be calculated directly. The amount of imide present, if any, can be determined by the procedure described in U.S.
Patent No. 3,892,716 (Edith Boldahuck)~
The time and temperature at which a polyamide acid powder can be conveniently heat-treated to produce at least 50~ imidization will depend on the sintering temperature of the sample and also on the amount of amine end groups. Oli-gomers prepared at higher mole ratio of diamine to dianhydride can be effectively imidized more rapidly and at lower temper-atures than oligomers prepared from equal mole ratios of diamine and dianhydride. To determine a suitahle time and 1~559~9 RD-8287 temperature for imidization, a polyamid2 acid powder can be heated for about two hours at a temperature about 10~ to 15C
lower than the sintering temperature. A sample of the heat-treated powder is thPn titrated to determine the amide acid content and imide content. The percent imidization is cal-culated as (meq. imide per g sample) x 100 (meq~ imide + meq. amide acid) per g sample If the percent imide in the heated sample is less than the desired amount~ the partially-imidized polyamide acid can be heated further to continue the imidization, using either a longer heating time or by carrying out the imidization at a somewhat higher temperature.
Particle size was measured using the Coulter Counter technique with the powder suspended in 3 percent aqueous sodium chloride.
In order that those skilled in the art will be Detter able to practice the present invention, the following examples are given by way of illustration and not by way of limitation.
All parts are by weight.
;~ Example 1.
Particulated polyetheramide acid was prepared by the following procedure:
A 5% solution of 2,2-bis[4-~3,4-dicarboxyphenoxy) phenyl]propane dianhydride (spADA) was prepared by dissolvin~
G.50 grams (0.0125 mole) in a sufficient amount of methyl-ene chloride in a first flask. A 5~ solution of 4,4'~methylene dianiline (MDA) was prepared by dissolving 2.47 grams (0.0125) moles of MDA in a sufficient amount of methylene chloride in a second flask. The BPADA solution and the MDA solution were added rapidly and simultaneously with vigorous stirring, at ~11-1 ~55999 RD-8287 room temperature (about 21-25~C) to a 500-mi.lliliter breaker, resulting in formation of a precipitate product within several seconds. Stirring was continued for about 10 minutes and there-after the precipitate product was separated from the reaction mixture by filtration. The product was washed with methylene chlorlde and thereafter dried under vacuum at room temperature to provide finely divided free flowing particles. Based on method of preparation and titration of the product for amine content, anhydride content, and amide acid content, the product was a.low molecular weight oligomeric polyetheramide acid adduct of MDA and BP~DA , substantially all the end groups of which were amine groups. The number average molecular weight (MW
of the polyetheramide acid was 2857 as calculated from the formula:
- 2 x lO00 MWn milliequivalents o~ amine/gram Additional particulated polyetheramide acid employ-ing different mol ratios of BPADA and MDA were also prepared;llnlike the above procedure, based on filtexing the reaction mixture, the precipitatecl polyetheramide acid was recovered by removing the solvent under reduced pressure.
:
The various polyetheram.ide acid samples we.re then analyzed or milliequivalents of amine per gram by potentio-metric titration with methane sulfonic acid using phenol:water 2S (90:10) as solvent. The various polyetheramide acid samples were then heated to imidize them in accordance with three different cycles at a temperature of 143C for 1-4 hours, a temperature of 165C for 1-2 hours and at 175C for 1/2-1 hour. In each heating cycle, the fresh polyetheramide acid powder was used. The following resultg were obtained, where "~ Imide" indicates the initial degree of imidization prior ~ 1 ~ 5 9 9 9 RD-8287 to heating, while "degree of Imidization" ~hows the extent of how far the particulated polyetheramide acid imidized. The imide content of the oligomer was determined by titration in acco.rdance with the method of Boldebuck U.S. patent 3,737,478.
In addition, the sintering temperatures, i.e., the temperature at which the powder is converted from the free flowing state to an agglomerated state of the various polyetheramide acid powders are also shown.
:~ \

' \

~ ,~, . \

\

\

: .

_ . _ ,_ ___ _______ 1 ~55g~9 h ~
,~
C~
o C
r'l r Ll~ I I I N 1` Irl _ ~ ~
OP
O .~ .D N r~) N 00 ~rl O N I a~ ~, co c~ t~
N L') 'a ~1 S, I ~ ~) N ~ O ~D

~J ~ L~ L~) ~
.C, ¦ 0 r~ N O cX) I-- ~D
: h ~ 1 'r a3 2 C~ ~ 1 ~) N ~ r O
~ ~ -~ t~

0;~ . ~ ¦ ~1 N N ~9 Lt~
,~ I ~ Lnr~ N N N ~1 oP
~1 a) O r-- ~ D O N O
rl : ~

:3: : :

rl ~ r~ a~ ~ N r-l 0 ~ CO ~D ~ W In ~i :
,o . ~5 ,-~ ~7 er tQ I C r-i N ~ ~ L~7 9 1 ~¢
_ p.~
I ~ r~

~ ~55~9 The above results show that amine end group content has a significant effect on the sintering temperature and on the imidization rate of the polyetheramide acid~
Exam~le_2.
A polyetheramide acid was prepared in accordance with the procedure of Example 1 utilizing equal molar amounts of the BPADA and the methylene dianiline. The resulting particulated organic solvent-free polyetheramide acid was found to contain 0.19 milliequivalents of anhydride end groups per gram and 2.37 milliequivalents of amide acid per gram by titration. A por-tion of the polyetheramide acid was then imidized utilizing a temperature of 165C for a period of 1-4 hours, to serve as a control sample. Additional samples of the polyetheramide acid were also treated with either dimethylamine (B) or trimethyl amine (C) at 25C by exposing the polyetheramide acid powder to the amine vapor several times after flushing between each exposure with nitrogen until a constant weight was obtained.
The amine treated polyetheramide acid powder was also titrated ~B for amine content after the gaseous amine treatme~t to ~e~-tant weight and then after 4 hours under flowing nitrogen at 165C. The imidized powders were then eonverted to films by a melt drawing technique or by being cast from N-methylpyrxoli-done and the resultiny film was then cured for 1/2 hour at 300C. The following results were ob~ained:

" ;, -" ~. 3.559~

h o ~ ~ c~ O O a O o ~ I U~
.~ ~ o o I ~ ~n El h ~d rC ¦ Ln O ~-1 ~ ~co cs~ 3 o~o ~ I
a o o ou a~
,~ ~ ~ O
IJ ~--I ~ Il~ I` t,) ~ 1~ ~D CO GO
Il) N ~J ~1 ~-~1 a) a x ~a ~1 ~
~ ~ ~1 I cn o ~0 H ¦ U . O

a) I tJ~ .
~1 ~
~rl aJ
~3 1~ ~ .

E3 ~ Q
rl . ~: t~
.
U~ ' -Q3 ~ r~
a~
.~
~ o ~ o ~u7 E~
~ ~ v ~
Q E~
U~ ~ ~
h h a,) h 00 ~ 0 ~ ~ O
hh 111 h 11~ h C~
U~ ~ U
8 , 1 ~55~

The above resul~s establish that thc polyetheramide acid can be successfully vapor treated in the solid state with a volatile organic amine. In addition, the volatile organic amine treatment enhances the rate of imidiæa~ion.
Ex~le 3.
In accordance with the procedure of Example 1, addi-tional polyetheramide acid powders were made which were imid-iæed at 165C in a nonoxidizing a~mosphexe for about 2 hours~
The imidized powders were then melt drawn on aluminum at about 250C and thereafter heated at 300C for 1/2 hour. The follow-ing results were obtained when the cut through was measured under a 1 kilo~ram load between 50.8 mil crossed wires.

Table YII
Composition Average BPAQA:~DA ~ I Temp. ~ *
1~1 270C Pass 2:3 325(' Borderline 3:4 380~C + Pass 345C Pass 4:5 380C + Pass 3BO~C ~ Pass

5:5 350C ~ Pass

6:7 330C + Pass

7:8 310C Pas~
* Film was bent and creased, ~he above re5ult5 show that the imidi~ed powder made in accord~nce with the preæent .invention can be converted to valuable films which eætablish that the powdars could also be electro~tatically coated onto a copper or aluminum conductor/

~155999 RD-8287 and can he fused and cured to pr~duce valuable insulating coatings.
~xample 4.
Polyetheramide acid powder was prepared in accordance with the procedure of Example 1 utilizing BPADA in a mole r~tio of one mole of sPAD~ per 1.2 moles of MDA. The resulting organic solvent-free polyetheramide acid powder was heated under nitrogen for 2 hours at approximately 170C. The powder was found to be imidized to about 80~. The imidi~ed polyetheramide acid was then electrostatically deposited onto a grounded aluminum foil utilizing a negative charged fluidized powder bed. The powder coated aluminum foil was then heated for 5 minutes in a 250C oven followed by 5 minutes in a 300C
oven. There was obtained a polyetherimide coated aluminum ~aly~th~r~m;d~
15 B foil having a cured ~ e film of about 5 mils thick free of bubbles and having excellent electrical integrity~
Example 5.
The organic solvent free polyetheramide acid powder prepared in Example 4 which had not been heated at 170C was spread uniformly onto the flat surface of an aluminum c~p.
The cup was placed in a 250C air circulating oven and was examined after 5 minutes. The powder had fused into a 5 mil film which ¢ontained many bubbles and surface imperfections.
After additional heating at 250C for 2-1/2 hours the film s~ill contained many bubbles. 'rhe film was found to be com-pletely unsuitable for electrical insulation purposes.
The above procedure was repeated except that the polyetheramide acid was imidized under nitrogen for 2 hours at 170C~ There was obtained a particulated polyetherimide powder which did not show any significant degree of sintering.

ll 1559~9 RD-8287 The powder was then spread in accordance with the previous procedure in an aluminum cup and then heated for 5 minutes a', 250C in an air circulating oven. There was obtained a smooth bubble-free film approximately 5 mils in thickness after a period of about 5 minutes. The film was then heated for 2-1/2 hours at 250C. The film remained smooth and bubble-free and it was found to have a dielectric strength at 60 Hertz of about 12.8 kv. This established that the imidization in accordance with the method of the present inven-tion at 2 hours at 170C was sufficient to overcome the problem of bubblin~ which characterized the polyetheramide-acid powder heated directly at 250C.
Although the above examples are directed to only a few of the ~ery many variables within the scope of the present invention, it should be understood that the present invention is directed to a much broader varie~ty of polyetherimide oligo~
mers and method for making such materials shown in the descrip-tion preceding these examples. These polyetherimide powders can be further characterized in that they can be fused to useful and bubble-free films without use of external mechanical pressure at temperatures between 200C to 250C. These films can be further heated to temperatures up to about 350C to flexibilize them.

Claims

The embodiments of the invention in which an exclu-sive property or privilege is claimed are defined as follows:
1. A method for making particulated substantially organic solvent-free polyetherimide which comprises heating particulated substantially organic solvent-free polyetheramide acid consisting essentially of chemically combined units of the formula, at a temperature in the range of from 135° C. to 175° C.
until the resulting particulated product consists essentially of at least about 70 mole percent of chemically combined imide units of the formula, based on the total moles of chemically combined imide and amide acid units without a substantial degree of sintering occurring in the resulting particulated product, where the polyetheramide acid is the product of reaction of organic dianhydride and organic diamine utilized in a mole ratio of 1 mole of organic dianhydride, per 1 to 1.5 mole of organic Claim 1 continued:
dianhydride is selected from the group consisting of (A) aroma-tic bis(ether anhydride)s of the formula, (B) mixtures of 1 or more of said bis(ether anhy-dride)s with up to 30 mole percent of benzophenone dianhydride of the formula, , with at least one organic diamine of the formula, H2N - R - NH2 , where said polyetheramide acid reaction product has a number average molecular weight of below about 5000, where Z is a member selected from , , , , , and ,

Claim 1 continued:

and divalent organic radlcals of the general formula, , X is a member selected from the class consisting of divalent radicals of the formulas -CyH2y-, , , -O-, and -S-, y is an integer from 1 to 5, and R is a divalent organic radical selected from the class consisting of aromatic hydrocarbon radicals having from 6 to about 20 carbon atoms and halogenated derivatives thereof, alkylene radicals having from 2 to about 20 carbon atoms, from C2 to about C8 alkylene terminated polydiorganosiloxane and divalent radicals of the general formula, Q is a member selected from the class consisting of -O-, -S-, and -C2H2x-, where x is an integer from 1 to 5.