WO1984004313A1

WO1984004313A1 - Improved polyamide-acids and polyimides

Info

Publication number: WO1984004313A1
Application number: PCT/US1984/000606
Authority: WO
Inventors: Vilas M Chopdekar; Abe Berger
Original assignee: M & T Chemicals Inc
Priority date: 1983-04-22
Filing date: 1984-04-17
Publication date: 1984-11-08
Also published as: EP0145727A4; DK626084A; EP0145727A1; JPS60501113A; DK626084D0

Abstract

Polyimide polymers which are thermally stable thermoplastic materials comprising the polycondensation reaction product of diether-containing aromatic dianhydrides and diether-containing aromatic diamines.

Description

IMPROVED POLYAMIDE-ACIDS AND POLYIMIDES

FIELD OF THE INVENTION

This invention relates to polyamide-acid and polyimide materials and more particularly, to thermally stable aromatic polyimide materials which are thermoplastic and to the method of preparing the same.

BACKGROUND OF THE INVENTION

Many attempts have been made to modify the thermal stability of various thermoplastic polymers by incorporating aromatic moieties in their molecular structure or to prepare new polymers, including polyimides, from aromatic monomers or oligomers which exhibit improved thermal stability but are thermoplastic in nature. These polymers, however, have generally not been completely satisfactory in that they either are not thermoplastic, are deficient in thermal stability, do not readily lend themselves to preparation by hot melt polymerization procedures or may lack some other useful characteristic such as good adhesion or resistance to organic solvents. The need for a thermoplastic polymer that is relatively inexpensive to prepare, is easy to fabricate into shaped objects and yet has temperature resistance and form stability at elevated temperatures is evident and the development of such a material would be highly desirable.

The preparation of polyimides which are stable at high temperatures is known. Thermally stable polyimides have been prepared by reacting various aromatic tetracarboxylic acids or their derivatives, such as dianhydrides, with aromatic diprimary amines to form polyamide-acids which are soluble in dipolar aprotic organic solvents. The polyamide- acids are then cyclized either by heat treatment or by chemical means to form the polyimides. Such polyimides, however, generally are intractable and infusible as well as being insoluble in most solvents making them difficult, if not impossible, to fabricate into molded parts. Moreover, when, a polyamide-acid prepolymer solution is used and then cured in situ to the polyimide, appreciable amounts of water are uncontrollably released in addition to evaporation of the solvent. This raises other limitations as to the type of uses for such materials.

In recent years, various aromatic and heterocyclic materials have been investigated in attempts to obtain thermally stable polyimides that could be more readily prepared and fabricated. It is disclosed, for example, in U.S. Patent Nos. 3,699,075 and 3,812,159 to Lubowitz, U.S. Patent No. 3,847,867 to Heath et al and U.S. Patent No. 3,879,428 to Heath that aromatic diether polycarboxylie acids and anhydrides thereof could be reacted with aromatic diamines to prepare thermally stable, high molecular weight polyimides which are soluble in organic solvents and fusible. Such polyimides are suggested as being suitable for use in preparing coatings, adhesives, films and the like or for fabrication into useful parts by conventional molding equipment. However, known polyimides prepared in this manner appear to exhibit certain deficiencies such as low Tg, inadequate adhesion to many substrates, and generally poor solvent resistance.

It has also been suggested, for example, in U.S. Patent No. 3,563,951 that thermally stable polyimides which are fusible and soluble in dipolar aprotic solvents can be prepared by reacting a nondiether-containing aromatic tetracarboxylic acid or an anhydride derivative thereof with high molecular weight diamine capped aromatic polyether oligomers. This approach requires the preparation and use of aromatic polyether oligomers which are end capped to prepare diamines. Apart from being chemically different from the organic diamines generally used in the preparation of polyimides, the nonuniformity of the oligomeric diamine compositions and known deficiencies in the moisture resistance of such polymers limit the suitability of polyimides prepared therefrom. Moreover, it was reported by P. Sachindrapol et al in a paper published in Makromolecular Science, Vol. 1, pp 667-670 (1980) that the reaction of 2,2-bis[4-(p-aminophenoxy)phenyl]propane with pyromellitic dianhydride and 4,4'-carbonyldi(phthalic anhydride) resulted in the preparation of insoluble polyimides. Thus, the reaction of an aromatic diether diamine with two different nondiether-containing dianhydrides resulted in the preparation of polyimides which were insoluble in dipolar aprotic solvents. It has also been reported by other researchers, for example, in U.S.S.R. Patent Nos. 224,056 and 257,010 to Koton et al that thermoplastic polyimides could be prepared in film form by thermal treatment of polyamide-acids formed by the polycondensation of particular diether-containing aromatic dianhydrides and particular diether-containing aromatic diamines. These disclosures are concerned only with the polycondensation of the dianhydride of resorcinol bis(3,4-dicarboxyphenyl ether) with resorcinol bis(4-amino- phenyl ether) and the dianhydride of hydroquinone bis (3,4-dicarboxyphenyl ether) with various aromatic diamines including hydroquinone bis(4-aminophenyl ether). However, such reports do not suggest either preparing or being able to prepare such polyimides in the original reaction solution or preparing thermoplastic polyimides from other reactants either directly or by a two-stage process. The unpredictability of directly preparing polyimides which are thermoplastic and soluble by reacting ether-containing or non-ether-containing dianhydrides and diamines is well known. Further, the ability to prepare such polyimides which are not deficient in certain desirable characteristics is even more unpredictable. This unpredictability is further pointed up in experiments reported herein.

DESCRIPTION OF THE INVENTION

In accordance with the present invention there is provided a polyimide composition which is thermoplastic and soluble and a polyamide-acid composition which is readily suitable for conversion to a thermoplastic and soluble polyimide which contains at least about 20 mole percent of a residue of the formula

I.

II.

or a mixture thereof and at least about 50 mole percent of a residue having the formula III.

IV.

or a mixture thereof, wherein Y is a divalent residue of an aromatic diether diamine and has the formula

wherein G is a substituted or unsubstituted group of the formula

where E is -S-, , linear or branched alkylene or

alkenylene of 1 to 8 carbon atoms, or where R and R¹

can be different lower alkyl or lower alkenyl or substituted or unsubstituted aryl groups of 6 to about 24 carbon atoms; and m is 0 or 1. A is a tetravalent residue of an aromatic diether dianhydride or other functionality which can generate the dianhydride residue in situ such as o-dicarboxylic groups and has the formula

where K is a substituted or unsubstituted group of the formula

where W is -O-, -S-, - , linear or branched alkylene or

alkenylene of 1 to 8 carbon atoms, or - where R and R¹ are

as defined? and m' is 0 or 1 and provided that m is 1 when m' is 0 or when m' is 1 and W is a -S- group and m' is 1 when m is 0 or when m is 1 and E is a -S- group.

Preferably W is -S- or - -, and E is preferably - - or

Especially preferred as the aromatic diether dianhydride is bis-[p-(3,4-dicarboxyphenoxy)phenyl]sulfide dianhydride, and the aromatic diether diamine is 4,4'-bis-(p-aminophenoxy)- diphenyl sulfone. It has been found that the use of an aromatic diether dianhydride

(especially one wherein W is -S- or ) permits the use of

an aromatic diether diamine in which E is so as to

provide a polyimide which is not only thermoplastic and soluble, but which also has a desirably high Tg and increased resistance to chemical attack.

It has been discovered that polyimides containing residues of the particular combination of diether-containing aromatic diamines and of diether containing aromatic dianhydrides herein described display properties that are totally surprising and unexpected. The polyimides of the invention are thermoplastic and soluble in many chlorinated hydrocarbon, dipolar aprotic, alkyl capped polyethylene glycol (alkyl capped glymes) solvents and mixtures thereof and mixtures of such solvents with various hydrocarbons, whereas it has been found that, as demonstrated in the experiments reported herein, polyimides containing other combinations of diether-containing diamine and diether- containing dianhydride residues do not display these characteristics. These polyimides are fusible, display tenacious adhesion to a variety of organic and inorganic substrates and exhibit excellent thermal stability. Further, the polyimides of the present invention can generally be prepared using melt polymerization as well as solution polymerization techniques.

Also provided is a method of preparing a thermoplastic, soluble polyimide which comprises reacting at elevated temperatures a dianhydride which comprises at least 20 mole percent of an aromatic diether dianhydride of the general formula

with a diamine which comprises at least 50 mole percent of an aromatic diether diamine of the formula

H₂N - Y - NH₂

wherein A and Y are as defined hereinabovej for the time necessary to remove all water from the reaction mixture and recover the resultant polyimide.

It has been discovered that when the particular combination of diether-containing aromatic diamines and dianhydrides herein defined are reacted in accordance with the practice of the invention there are unexpectedly prepared polyimides which are both tractable and soluble. In contrast thereto, it is known that the reaction of many other diamines and dianhydrides will not prepare polyimides which display such characteristics. Moreover, it has been found as demonstrated in the experiments herein, that the reaction of particular combinations of diether-containing aromatic dianhydrides and diether-containing aromatic diamines will not result in the preparation of the desired polyimides. Thus, the surprising and unexpected results achieved by the present invention are pointed up, for example, by referring to the reaction of a diether- containing biphenyl dianhydride and a diether-containing biphenyl diamine which was found to result in the preparation of an insoluble polymer while a soluble polyimide was prepared by the reaction of a diether- containing biphenyl dianhydride with a diether-containing sulfonyl diamine.

The polyamide-acids and polyimides of this invention are polymers which contain at least about 20 mole percent of a residue of the formula I.

II .

or mixtures thereof; and at least about 50 mole percent of a residue having the formula

Ill,

IV.

or a mixture thereof. In formulae I-IV, A and Y are as previously described.

The polymers of the invention are generally composed of recurring units having the formula

(a)

(b)

or mixtures thereof.

In formulae (a) and (b) above, k and k' are the same or different positive integers of one or more and represent the number of different polymer blocks in the polymer of formula (a) and (b); and r and r' are the same or different integers greater than 1 and preferably they have values from 10 to 10,000 or greater. They represent the number of times the respective radical is repeated in the polymer chain.

Exemplary of the radicals included in A are:

Aromatic diether dianhydrides that are suitable for use include, for example,

2,2-bis[4-(3,4-dicarboxyphenoxy)phenyl]propane dianhydride, 2,2-bis[4-(2,3-dicarboxyphenoxy)phenyl]propane dianhydride, 4,4'-bis(3,4-dicarboxyphenoxy)diphenyl dianhydride, bis-[p(3,4-dicarboxyphenoxy)phenyl]sulfone dianhydride, and bis[p-(3,4-dicarboxyphenoxy)phenyl]sulfide dianhydride. Exemplary of the radicals included in Y are:

and the like. Illustrative of such suitable aromatic diether diamines are, for example:

4,4'-Bis-(p-aminophenoxy)diphenyl sulfide 4,4'-Bis(3"-aminophenoxy)diphenyl sulfide 4,4'(3"-aminophenoxy,4''aminophenoxy)-diphenyl sulfide

4,4'-Bis-(p-aminophenoxy)diphenyl sulfone 4,4'-Bis-(3"-aminophenoxy)diphenyl sulfone 2,2-Bis-[4'(p-aminophenoxy)phenyl] propane 2,2-Bis-[3'p-aminophenoxy)phenyl]propane

1,1-Bis-[4'(p-aminophenoxy)phenyl]ethylbenzene. In order to prepare a polyimide (or a polyamide-acid which is readily convertible to the polyimide) which is thermoplastic and soluble, it is essential that at least about 20 mole percent of an aromatic diether dianhydride be reacted with at least about 50 mole percent of an aromatic diether diamine. The aromatic diether dianhydride will have the formula

while the aromatic diether diamine will have the formula

H₂N-Y-NH₂ wherein A and Y are as previously described.

It has also been found that polyimides (and polyamide acids readily convertible into the polyimides) which are thermoplastic and soluble, but yet have higher Tg temperatures and improved resistance to chemicals may be prepared if the polyimide contains at least ten mole percent of one or more nondiether dianhydrides, one or more nondiether diamines or mixtures thereof; the term "nondiether" as employed herein is intended to encompass non-ethers as well as monoethers. It should, nevertheless, be understood that when the nondiether dianhydrides and/or the nondiether diamines are utilized in an amount of at least ten mole percent, the polyimide must still contain at least about 20 mole percent of the aromatic diether dianhydride and at least about 50 mole percent of the aromatic diether diamine. Thus the nondiether dianhydrides may be used in an amount of up to about 80 mole percent of the total anhydride requirement of the reaction system, while the nondiether diamines may be utilized in an amount of up to about 50 mole percent of the diamine requirement of the reaction system (the reaction system of course requires a total dianhydride content of 100 mole percent and a total diamine content of 100 mole percent). The nondiether dianhydride may be represented by the formula

wherein D is a tetravalent residue of a nondiether- containing tetracarboxylic acid anhydride and is selected from the group consisting of substituted or unsubstituted aliphatic groups of 4 to about 40 carbon atoms, cyclo- aliphatic groups of :5 to about 32 carbon atoms, heterocyclic groups of 4 to about 40 carbon atoms including at least one hetero atom such as -N-, -S-, and -O-, aromatic groups of 6 to about 40 carbon atoms, and combinations thereof.

Preferably, the nondiether dianhydride is aromatic in nature. Thus, preferably, Di is a C₆-C_{4 0} aromatic radical such as a substituted or unsubstituted phenyl, biphenyl, naphthyl, etc. or a tetravalent group of the formula

wherein m" is 0 or 1 and Q is -O-, -S-, -

-, - -, -S-S-,

- -, linear or branched chain alkylene of 1 to 8 carbon

atoms, or - wherein R" and R''' can be the same or

different substituted or unsubstituted lower alkyl or aryl groups.

Exemplary of the groups included in D are:

and specific nondiether dianhydrides include for example, pyromellitic dianhydride,

3,3',4,4'-benzophenone tetracarboxylic dianhydride, 2,2',3,3'-benzophenone tetracarboxylic dianhydride, 3,3',4,4'-diphenyl tetracarboxylic dianhydride, 2,2',3,3'-diphenyl tetracarboxylic dianhydride,

2,2-bis-(3,4-dicarboxyphenyl)propane dianhydride, 2,2-bis-(2,3-dicarboxyphenyl)propane dianhydride, Bis-(3,4-dicarboxyphenyl)ether dianhydride, Bis-(3,4-dicarboxyphenyl)sulfone dianhydride, Bis-(3,4-dicarboxyphenyl)sulfide dianhydride,

1,1-bis-(2,3-dicarboxyphenyl)ethane dianhydride, 1,1-bis-(3,4-dicarboxyphenyl)ethane dianhydride, Bis-(2,3-dicarboxyphenyl)methane dianhydride, Bis-(3,4-dicarboxyphenyl)methane dianhydride, 2,3,6,7-naphthalene tetracarboxylic dianhydride, 1,2,4,5-naphthalene tetracarboxylic dianhydride, 1,2,5,6-naphthalene tetracarboxylic dianhydride, Benzene-1,2,3,4-tetracarboxylic dianhydride, Perylene-3,4,9,10-tetracarboxylic dianhydride, Pyrazine-2,3,5, 6-tetracarboxylic dianhydride, Thiophene-2,3,4,5-tetracarboxylic dianhydride, naphthalene-1,4,5,8-tetracarboxylic dianhydride, decahydronaphthalene-1,4,5,8-tetracarboxylic dianhydride, 4,8-dimethyl-1,2,3,5,6,7-hexahydronaphthalene-1,2,5,6- tetracarboxylic dianhydride,

2,6-dichloronaphthalene-1,4,5,8-tetracarboxylic dianhydride, 2,7-dichloronaphthalene-1,4,5,8-tetracarboxylic dianhydride, 2,3,6,7-tetrachloronaρhthalene-1,4,5,8-tetracarboxylic dianhydride, phenanthrene-1,8,9,10-tetracarboxylic dianhydride, cyclopentane-1,2,3,4-tetracarboxylic dianhydride, pyrrolidine-2,3,4,5-tetracarboxylic dianhydride, pyrazine-2,3,5,6-tetracarboxylic dianhydride, 1,2,3,4-butane tetracarboxylic dianhydride, 3,4,3',4'-benzophenone tetracarboxylic dianhydride, azobenzene tetracarboxylic dianhydride, 2,3,4,5-tetrahydrofuran dianhydride, p-phenylene-bis (trimellitate) anhydride, 1,2-ethylene-bis (trimellitate) anhydride, 2,2-propane-bis (p-phenylene trimellitate) anhydride,and 4,4'-[p-phenylene-bis (phenylimino) carbonyl diphthalic] anhydride. As described hereinabove, it has been found that up to 50 mole percent of the nondiether diamines used to prepare the thermoplastic polymers of the present invention. Such nondiether diamines may be represented by the general formula

H₂N - B - NH₂

wherein B is a divalent residue and can be aliphatic or cycloaliphatic, including alkylene or alkenylene, of 2 to about 20 carbon atoms, polyoxyalkylene of from 4 to about 500 carbon atoms, cycloalkylene of 4 to 8 carbon atoms, heterocycloalkylene of 6 to about 20 carbon atoms, or preferably, an aryl group of 6 to about 24 carbon atoms. Suitable aromatic nondiether diamines can be those where B is phenylene, diphenylene, naphthylene, or aromatic nondiether diamines wherein B can be of the formula

wherein m''' is 0 or 1, and X is branched or linear alkylene

of 1 to 20 atoms, -S-, -S-S-,

wherein R or R₁ can be the same or different lower alkyl, lower alkenyl, or aryl groups. Any of the aryl nuclei can be substituted by lower alkyl, lower alkoxy or other non- interfering substituent groups.

Residuum B can be mono-carbocyclic aromatic or polycarbocyclic aromatic of 6 to 14 carbon atoms such as benzene, naphthalene, anthracene, etc. These residuum can be further substituted by non-interfering groups such as lower alkyl. Residuum B can also be a heterocyclic aromatic of 6 to 20 carbon atoms while the hetero atoms are one or more of -N-, -O- and -S-, such as pyridine, pyrimidine, pyrazine, oxadiazine, oxathiazine, triazine, benzofuran, thionaphthene, indole, quinoline, benzoxazole, benzothiophene, carbazole, and the like.

Among the nondiether diamines that are useful are: m-phenylenediamine, p-phenylenediamine, 2,2-(4,4'-diaminodipheny1)propane,

4,4'-diaminodiphenylmethane (hereinafter referred to as "methylenedianiline"), benzidine,

4,4'-diaminodiphenyl sulfide, 4,4'-diaminodiphenyl sulfone, 4,4'-diaminodiphenyl ether, 1,5-diaminonaphthalene, 3,3'-dimethylbenzindine, 3,3'-dimethoxybenzidine, bis(p- -methyl- -aminopentyl)benzene, 1,3-diamino-4-isopropylbenzene, 1,2-bis(3-aminopropoxy)ethane, m-xylylenediamine, p-xylylenediamine, bis(4-aminocyclohexyl)methane, decamethylenediamine, 3-methylheptamethylenediamine, 4,4'-dimethylheptamethylenediamine, 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, and mixtures thereof. Also suitable are the diamino macrocyclic dibenzomacrocyclic crown ethers.

Additionally, a functionally substituted nondiether diamine can be used as part of the nondiether diamine component to provide functional sites for grafting and cross-linking, for modifying the polyimide to become photosensitive, hydrophilic, antiseptic, fungicidal and the like.

The functionally subs-tituted nondiether diamine will have the general formula

or

or

or

where B is an aromatic nucleus as hereinabove described; X

and X_a independently, are -O-, -S-, - -, linear or

branched alkylene of 1 to 20 atoms, or a carbocyclic or heterocyclic group containing from 6 to 14 atoms in the nucleus and the hetero atoms are selected from N, S and O. z₁ and z₂, each independently, is 0 or 1 and when z₁ and/or z₂ is 0, the adjacent aromatic nuclei may be fused, and F³ is a functional group.

The term "functional group" is intended to denote atoms or groups of atoms that confer characteristic chemical properties on the molecule containing said atoms.

Thus, it will be apparent that the chemical composition of the functional group F³ can vary, depending on the characteristic chemical properties desired. F³ can be acrylyl, methacrylyl or other unsaturated group capable of free-radical initiated cross-linking; it can be the naphthoquinone-diazide radical to provide U.V. sensitivity; it can be a quaternary ammonium group to provide fungicidal activity or increased hydrophilicity. F³ can also be

- O - R_n , ;

-O -

- R_n , ;

- R_n' ;

-O - R_n ,;

C1 , Br , I or F ;

-SH;

-SR_n,;

-OH;

-SO₃H;

-COOH;

-R_n, ;

-CN;

-OCN ;

-NCO;

or

wherein R_n, is hydrogen, alkyl of 1 to 7 carbon atoms or alkenyl of 2 to 7 carbon atoms;

R_n and R_P each independently is hydrogen, alkyl of 1 to 7 carbon atoms, alkenyl of 2 to 7 carbon atoms, or -C-R_q where R_q is alkyl of 1 to 7 carbon atoms.

Exemplary suitable functionally substituted nondiether compounds include: 2,4-diamino-chlorobenzene; 2,4-diaminothiophenol; 2,4-diaminophenol; 3,5-diaminobenzoic acid; methyl-2,4-diaminobenzoate; 2,4-diaminoacetamide;

1-(para-carbomethoxyphenoxy)-2,4-diaminobenzene; p-(2,4-diaminophenoxy) acetamilide; 3-mercapto-4-amino-4-aminobiphenyl; 1(2'-cyanophenyl)-2,5-diaminonaphthalene; and the like.

The aromatic diether dianhydrides and aromatic diether diamines, and nondiether dianhydrides and nondiether diamines that are suitable for use in preparing the polyimide polymers of the present invention can be prepared by methods well known in the art.

For example, the aromatic diether dianhydrides can be prepared by coupling an appropriate xylene derivative, such as 4-bromo-o-xylene or alkali metal salt of 3,4-xylenol, with an appropriate aryloxide or halide via the Ullmann Ether Synthesis, using copper catalyst, followed by oxidation of the methyl aubstituted groups and dehydration to effect ring closure.

wherein W and m' are as hereinabove defined. When the nondiether dianhydrides and/or the nondiether diamines are utilized, the resultant polyimides and the polyamide acids which are readily convertible into such polyimides, will contain recurring structural units of formula (a), formula (b) but also: up to about 50 mole percent recurring structural units of formula (c), formula (d); or up to about 80 mole percent of formula (e), formula (f); or up to about 40 mole percent of formula (g), formula (h):

(c)

(d)

(e)

(f)

(g)

(h)

Wherein A, B, D and Y are as previously described, and wherein j and j', i and i' and h and h' are the same or different positive integers of one or more and represent the number of different polymer blocks in the composition, and s and s', t and t' and u and u' are the same or different positive integers greater than one and represent the number of times the structural unit is repeated in the polymeric chain.

The polyimide compositions of this invention are thermoplastics which are capable of being readily formed and shaped as by molding, extruding or calendering. Products fabricated therefrom exhibit good thermal resistance as well as resistance to degradation caused by various environmental conditions. Additionally, the polymeric compositions of the invention are soluble in many conventional solvents, such as halogenated aromatic hydrocarbons, dialkyl capped glymes and dipolar aprotic solvents. Solutions of these polymers can be used to coat a variety of substrates including various electrical or electronic components to provide electrical insulation and protection against mechanical or environmental damage. Such solutions can also be used to cast films or spin fibers which exhibit generally improved thermal resistance. It has also been found that the polymeric compositions herein described possess good adhesion to a variety of substrates and thus can be used as primary or secondary adhesives or coatings for a number of different metallic and non-metallic materials. They can be applied by either solvent, film or hot melt application techniques. The polyimide-acids of the invention can be readily converted to thermoplastic polyimides by thermal or chemical means or both.

Surprisingly, it is apparent that in accordance with the practice of the invention there are a number of variables available to the chemist in formulating useful polyimides.

As a general proposition, it is known that the polyimide formed from a nondiether aromatic dianhydride and a nondiether aromatic diamine must be prepared by solvent polymerization techniques and are intractable and insoluble in organic solvents. In an attempt to work with these materials, several approaches have been adopted by the art. One involves preparing the polyamide-acid, which is soluble and tractable and after the material is in place or has been shaped and formed, heating to form the imide.

.Another approach involves the use of diether dianhydrides. Prior art polyimides based on these anhydrides, although soluble and tractable, have been found to display deficiencies that detract from their suitability for use in a number of applications. Thus, they have poor adhesion to a number of substrates, have a low Tg, and poor solvent resistance.

Other approaches have involved the selection of the diamine. For example, in U.S. Patent No. 3,563,951, it is reported that high molecular weight diamine capped polyether oligomers reacted with nondiether aromatic dianhydrides will form thermally stable polyimides which are fusible and soluble in dipolar aprotic solvents. This approach requires the prior preparation of high molecular weight aromatic polyether oligomers before forming the diamine. Further, it is known that the presence of such moieties in a polyimide or other molecular structure would reduce the moisture resistance thereof, particularly at high temperatures. Moreover, it was reported by P. Sachindropol et al, ibid., that the reaction of a bisphenol-A diether diamine monomer with nondiether dianhydrides resulted in the preparation of insoluble polyimides.

It has been found that the polyimide of the present invention prepared from the diether dianhydride and diether diamine as herein described, displays properties that are totally surprising and unexpected. The polyimide is thermoplastic and soluble in a variety of solvents including, for example, chlorinated hydrocarbon solvents, dipolar aprotic solvents, alkyl capped glymes and the like; the polyimide also displays as well as displaying excellent thermal stability and adhesion characteristics which are superior to those found with other known polyimides. Thus, polyimides containing the diether dianhydride and diether diamine residues herein described can be processed quite readily, using conventional fabrication techniques, into molded products that display high thermal stability or can be used for coating and adhesion applications where tenacious adhesion and thermal stability would be important. Further, it has been found that a polyimide derived from the diether dianhydride and diether diamine herein described is soluble and thermoplastic even when a substantial portion of the diether dianhydride and/or diether diamine is replaced by a nondiether diamine and/or nondiether dianhydride. Polyimides of the invention which are tractable and soluble in chlorinated hydrocarbon, dipolar aprotic and the like solvents can be prepared with up to about 80 mole percent of the dianhydride content being a nondiether dianhydride and/or with up to about 50 mole percent of the diamine content being a nondiether diamine.

Thus, the properties of the polyimides of the invention can be varied over a very broad range, depending on the particular combination of reactants that are chosen. In addition to adjusting the reactants, one can also modify the properties of polyimides of the invention by blending different polyimides.

The reaction between the above described aromatic diether dianhydride component and aromatic diether diamine component to prepare the polyamide-acid and polyimide compositions of the invention may be effected in a suitable solvent and optionally in the presence of a condensation catalyst. The solvent should dissolve the reactants as well as the product. Suitable solvents include, for example, a dipolar aprotic liquid such as N,N-dimethylformamide (DMF), dimethylacetamide, N-methyl-2-pyrrolidone, hexamethyl- phosphortriamide, dimethyl sulfoxide (DMSO), tetramethyurea and the like; chlorinated solvents such as chlorobenzene, dichlorobenzene, trichlorobenzene and the like; glyme solvents such as ethyleneglycol dimethylether, diethylene- glycol dimethyl ether and the like; and mixtures thereof.

Where combinations of reactants will be employed, e.g. combinations of dianhydrides and/or diamines, attention should be paid to the reactivity of the components. In synthesizing the polymers of the invention, the monomers are generally employed in equimolar amounts. While some excess of one of the monomers is not detrimental to the condensation reaction, a considerable excess may result in the production of lower molecular weight products or undesirable by-products.

Since all or a substantial part of the dianhydride component and the diamine component employed to produce the polyimide and polyamide-acids of the invention will be the aromatic diether dianhydride and aromatic diether diamine compounds herein described, the polymer will contain from 20 mole percent of intercondensed polyimide or polyamide-acid diether containing diamine and dianhydride residue components to 100 mole percent diether polyimide with no nondiether diamine or dianhydride residue components. Thus, there can be used from about 50 mole percent to 100 mole percent of the diether diamine reactant and from about 20 mole percent to 100 mole percent of the diether dianhydride reactant or mixtures thereof; however, the majority of applications will call for polymers containing from about 65 mole percent to 100 mole percent of the diether-containing reactants.

Where the polyimide will contain 100 mole percent of the diether diamine residue and diether dianhydride residue components, the following sequence of reaction steps has been found to be effective:

(a) a reaction mixture of a diether dianhydride and diether diamine is prepared and stirred in a suitable solvent.

(b) the reaction between the two reactants produces water in a refluxing reaction.

(c) the water produced by the refluxing reaction is removed by distillation. (d) upon complete removal of the water, the resulting reaction product solution is cooled and polymer recovered by a suitable process such as, for example, by filtering and mixing the product solution with an excess of methanol to precipitate the reaction product;

(e) the precipitated polymer is separated by filtration, washed several times in fresh methanol and dried, preferably at an elevated temperature of about 60C to 80C, preferably under vacuum to effect volatilization of the methanol and any adhering solvent. Where the polyimide will contain a nondiether amine and/or nondiether dianhydride component in addition to the diether diamine and diether dianhydride reactants, the polyimide may be prepared with a random molecular configuration, a block-block molecular configuration, a random -block- random molecular structure, a block-random molecular structure depending on the properties desired and the reactivity of the relative combination of reactants. Thus, the diether dianhydride component can be first reacted with the diether diamine component in a suitable solvent. The components may be either a single diether diamine or diether dianhydride or mixtures thereof. After completion of the reaction and removal of water that may be produced, the third component and/or fourth component, either a nondiether diamine, a nondiether dianhydride or mixtures thereof is added to the reaction product mixture and the mixture is heated to an elevated temperature for a sufficient time to produce a polymeric solution of the polyimide which polymer may be recovered as described above or by other suitable method known in the art.

Where the desired product is a polyamide-acid, the diamine component or components are combined and cooled to 0ºC. The dianhydride component or components is thereafter added gradually, over an extended period of time with the temperature being maintained from about 0ºC to about 100°C, and preferably from about 20°C to about 40ºC. The poly- amide-acid forms readily without the application of heat and without catalysts.

Alternatively, the polyamide-acids and polyimides of the invention can also be prepared by hot melt polymerization, in the absence of solvents. The materials are simply combined in generally equimolar amounts, mixed and heated. One such method involves combining the materials in an extruder heated to about 300°C and extruding, on a continuous basis, the polyimide product.

It may also be desirable to add a chain stopper to the reaction mixture to control the molecular weight of polymer produced. For example, phthalic anhydride or aniline may be used, preferably in an amount from about 1 percent to 5 percent by weight.

As indicated, polyamide-acids and polyimides of the invention are suitable for use in a number of electronic applications such as wire enamels, as conformal, protective, junction and passivation coatings for electrical devices, printed circuit boards and semiconductor devices. They are suitable for use with electric devices since they have several desirable physical characteristics. The polyimide is one which can easily be applied and cured in place. The polyimide will not degrade in use, and it generally enhances the electrical characteristics of the device to which it is applied. It adheres very tenaciously to the surface to which it is applied and prevents migration of ions on the surface of the device. When employed with semiconductor devices, it does not release any materials during drying cycles which are deleterious to the operating characteristics of the device. The polyimide exhibits good abrasion resistance to protect the surfaces to which the coating is applied.

The polyimide is also capable of being applied in multiple layers to provide a thick coating when required. The polyimide is able to bond well to itself as well as to many metallic and non-metallic substrates.

When a polyimide is not capable of inherently exhibiting all of the desired characteristics to the degree necessary, it is capable of being modified to achieve the desired end result. Often times stray alkali and heavy metal ions cause undesirable degradation of electrical properties of semiconductor devices. Therefore, the polyimide can be modified with chelating materials admixed therewith or chemically bonded thereto. Ease of application to the surface to be protected and reasonably short drying times are still retained. This is of particular interest when the coating material is employed in the manufacture of mass produced electronic devices.

The polyimide is translucent. Such a material, while the other desirable characteristics, is useful to fabricate photovoltaic devices. Particularly, it is desirable to bond a light emitting diode to the surface of another semiconductor device to turn the device "on" and "off" in response to the operation of the light emitting diode. The copolymer material of this invention is also applicable for use in bonding protective covers to exposed surfaces of photovoltaic devices such as solar cells. The dielectric strength of the polyimide may be further enhanced by admixing suitable filler materials therein. Preferably, an electrically insulating material having a dielectric constant which is approximately the same as the polyimide is admixed therein. The filler material is uniformly distributed throughout the polyimide coating as applied to a substrate. Other materials suit able as a filler material are those materials known to have a relatively good ability to resist electrical conduction although their dielectric constant is higher than that of the polyimide. Suitable electrically insulating filler materials have been found to include aluminum oxide, silicon oxide, glass fibers, boron nitride, quartz, mica, magnesium oxide, activated polytetrafluorethylene and the like in a finely divided, or pulverized form. Whether a filled or unfilled polyimide is employed, the electrical properties of a given device are enhanced.

The polyimide has an inherent elasticity to withstand repeated cycling from dipping into liquid gases at a temperature of approximately -100°C and back into a liquid gas for a temperature excursion range of about 200°C or more. Additionally, it has been found that the polyimides withstand short temperature excursions up to about 350ºC to 550ºC without degradation of their electrical characteristics.

The polyimide can be applied over electrically insulating layers of silicon oxide, silicon nitride, aluminum nitride and the like; it can also be applied as an insulating layer in place of those materials.

A thermoplastic polyimide, which is substantially inert, temperature resistant, capable of flowing upon heating, and having superior dielectric properties, finds application as a passivation coating. Following application of the polyimide to the device, holes can be made in the polyimide, wires attached to the device and the device heated; the polyimide will flow to fill the voids around the wires, thus providing a self-levelling passivation coating.

Because of their adhesive and dielectric properties, the polyimides can be used to combine two or more layers of chips to provide multilayer semiconductor devices. The thermoplastic polyimides are processable by extrusion, compression and injection molding, film casting and solution fiber spinning techniques. Because of their high elongation and toughness, they are particularly useful in thin-film products such as films, enamels, adhesives, coatings and fibers. They can be molded into parts that retain high strength at 200°C and as high as 250°C for short periods, such as, for example, during processing of graphite and glass-fiber laminates. They can be extruded into tubing and the like or onto substrates such as conductive wire and can be co-extruded with other polymers to prepare multilayer tubing or insulated wire which display good adhesion between layers to provide improved high temperature and electrical properties. Laminates, films and coatings display a minimum of voids or imperfections because no reactions products are formed at processing temperatures.

The thermoplastic polyimides of this invention have the following general properties: they are molded simply by exceeding the glass transition temperature for sufficient time with application of pressure for good flow; their elongation imparts good machineability with low brittleness; the polyimides require no postcure to develop full high- temperature properties; they can be reclaimed and used as required; and defective laminates can often be corrected by reapplying heat and pressure; they can be cast into film from solution using .conventional casting machines, the films being useful in both supported and unsupported applications; the films adhere well by heat-sealing to themselves as well as to other polyimides; they can be solution-spun into fibers to produce flame resistant, high temperature resistant fabrics; they can be molded with various fillers into parts having high strength at high service temperatures and flame resistance; unfilled molded parts have low coefficients of thermal expansion while glass, graphite and asbestos-filled parts give still lower coefficients of thermal expansion; they provide parts that wear well with low friction and molding compounds filled with graphite powder, molybdenum or tungsten disulfide or PTFE produce parts with self-lubricating wear surfaces such as piston rings, valve seats, bearings, seals and thrust washers.

Laminates are made in high-pressure platen presses, low-pressure vacuum bags or moderate pressure vacuum autoclave bags. Solutions can be used as laminating varnish to impregnate glass, graphite, quartz or the like cloth, or glass, boron, graphite, ARAMID or the like fibers to produce laminates with flame-resistance, high-temperature strength and good electrical properties which have utility in radomes, printed circuit boards, radioactive waste containers, as well as for turbine blades and structural parts which are used close to the hot engine environment.

Polyimide film has good mechanical properties through a range from liquid helium temperature to 450°C. It has high tensile and impact strength and high resistance to tear initiation. Room temperature properties are comparable to hose of polyester film while at 200°C, the film can be bent around a 1/4-inch mandrel without breaking and at 250°C it has a tensile strength on the order of 3500-4000PSI. The foregoing specification has described a variety of molecular configurations and applications of a polyimide and a polyamide-acid. The invention is further illustrated in the following examples. All parts and percentages are by weight unless otherwise indicated. EXAMPLE 1

Preparation of a thermoplastic diether polyimide To a one-liter flask equipped with a stirrer, a condenser, a thermometer, a Dean Stark trap, and a nitrogen blanket were added 16.9 grams (0.039 moles) of 4,4'-bis- (p-aminophenoxy)diphenyl sulfone and 0.1 grams of p-toluene sulfonic acid as catalyst. A solvent mixture containing 322 grams of chlorobenzene and 138 grams of N-methyl pyrrolidone was added and the charge was agitated until a clear solution was obtained. Then 20.00 grams (0.039 moles) of 4,4-bis- (3",4"-dicarboxyphenoxy)diphenylsulfide dianhydride was charged to the reactor, the reaction mixture was agitated, heated to reflux and held at reflux during which time water formed during the condensation reaction (1.4 g water was obtained as compared to 1.4 g calculated) was distilled and removed. The reaction mixture was then held at 138° to 145° for 8 hours under reflux.

After completion of the reaction, the reaction product, which was a clear solution, was cooled and filtered, 485 grams of filtered polymeric solution being obtained. The filtered polymeric solution was then added to 4 liters of methanol to precipitate the polymer. The precipitated polymer was washed with fresh methanol and dried at 60°C in an air circulatory oven. The dried polymer product weighed 34 grams (95.8% yield-35.5 grams calculated). A portion of the polymer product was analyzed and determined to have a Glass Transition Temperature (Tg) of 207°C and a molecular weight Mw of 54.5x10 and Mn of 28.6x10³.

A 25 percent solution of the polyimide reisin in N-methyl pyrrdlidone was prepared and then brushed on the surface, of 3 glass sides to form coatings about 1 mil in thickness. The coated slides were then placed in an oven, preheated to about 150°C and maintained there for a period of 2 hours. The coated slides were removed from the oven and cooled. The film was bonded tenaciously to each of the glass slides and did not lift off when chipped at with a razor blade or when adhesive tape that was firmly pressed to the coating, was pulled away.

EXAMPLE 2

Preparation of a thermoplastic diether polyimide Into a 250 ml, 3-neck flask fitted with a stirrer, a condenser, a Dean Stark trap, a thermometer, a thermowatch, a heating mantle and a nitrogen blanket, 4.5 grams (0.01 moles) of 4,4'-bis-(p-aminophenoxy)diphenyl sulfone were charged under a nitrogen atmosphere along with 83.75 grams of N-methyl pyrrolidone. The mixture was agitated until a clear solution was obtained. Then 4.78 grams (0.01 moles) of 4,4' -bis-(3' 4' -dicarboxyphenoxy)diphenyl dianhydride were charged into the flask along with 100 parts of N-methyl pyrrolidone under a nitrogen atmosphere. 0.025 parts of p-toluene sulfonic acid (catalyst) were also charged in the flask. The reaction mixture was agitated and heat was applied until the reflux temperature was achieved. The reaction mixture was then maintained at reflux temperature for two hours. During this time about 100 parts of solvent was distilled off along with the water formed during the condensation reaction. The temperature of the reaction mass was then reduced to and controlled between 195°C to 198°C for about 4 hours. After completion of the reaction the heat was turned off and the reaction mass was allowed to cool to 100°C.

A clear polymer solution was obtained which was poured into methanol to precipitate the polymer. The polymer was washed with fresh methanol and then dried at ambient temperature. The glass transition temperature of the polyimide resin was determined to be 245ºC. EXAMPLE 3

Preparation of a thermoplastic diether polyimide Using the procedure and apparatus of Example 2, 2.1 grams (0.01 moles) of 2,2-bis- [4-(p-aminophenoxy)- phenyl]propane and 2.39 grams (0.01 moles) of 4,4'-bis- (3",4"-dicarboxyphenoxy)diphenyl dianhydride were reacted under reflux for 2 hours during which 155 grams of solvent was distilled out along with water formed during the reaction. This was followed by heating at a temperature of 195°C to 198°C for 4 hours. A clear, light brown colored polymer solution was obtained from which the polymer was precipitated by mixing with methanol. The precipitated polymer was washed with fresh methanol and air dried. The polyimide polymer was found to have a Glass Transition Temperature (Tg) of 222°C. An adhesion test using the procedure described in Example 1 was run with the polymer of this example and the coatings were found to tenaciously bond to the glass slides.

EXAMPLE 4 Preparation of a thermoplastic diether polyimide

Using the procedure and apparatus of Example 1, 8.2 grams (0.02 moles) of 2, 2-bis-[4'-(p-aminophenoxy)- phenyl]propane charged along with 250 grams of N-methyl pyrrolidone were reacted with 10.2 grams (0.02 moles) of 4,4'-bis-(3",4"-dicarboxyphenoxy)diphenyl sulfide dianhydride added to the reaction mixture with 280 grams of N-methyl pyrrolidone. At the reflux temperature of the system 300 grams of solvent were distilled out along with water formed during the condensation reaction over a period of 2 hours. The temperature of the reaction mass to loweredto and controlled at 195º-198°C for overnight. A clear, light brown colored polymer solution was obtained from which the polymer was precipitated by mixing with methanol. The precipitated polymer was washed with fresh methanol and then air dried.

Using the adhesion test procedure of Example 1 samples of the polyimide composition in solution were applied to glass slides; aluminum, zinc and iron coupons; and plastics plaques (RYTON, polyepoxides) and hot air cured. Each of the coating samples was found to exhibit tenacious adhesion to the substrates.

EXAMPLE 5 Preparation of a thermoplastic diether polyimide

Using the procedure and apparatus of Example 2, 4.05 grams (0.01 moles) of 4,4'-bis(p-aminophenoxy)-diphenyl sulfide charged with 50 grams of N-methyl pyrrolidone were reacted with 5.10 grams (0.01 moles) of 4,4'-bis- (3",4"- dicarboxyphenoxy)diphenylsulfide dianhydride charged along with 113.5 grams of N-methyl pyrrolidone. At the reflux temperature of the system, 60 grams of solvent along with water were distilled off over a period of 2 hours and then the reaction mass was maintained at 195°-198ºC for a period of 3 hours.

A clear polymer solution was obtained from which the polymer was precipitated by mixing with methanol. The polymer was washed with fresh methanol and air dried.

An adhesion test was run using the procedure of Example 1 and coatings prepared from the polyimide resin of this Example were found to tenaciously bond to glass slides.

EXAMPLE 6

Preparation of a thermoplastic diether polyimide Using the procedure and apparatus of Example 2, 4.5 g (0.01 moles) of the sulfide diether diamine charged with 50 g of N-methyl pyrrolidone of Example 5 were reacted with 5.42 g (0.01 moles) of the sulfonyl diether dianhydride of Example 2 charged with 117.10 g of N-methyl pyrrolidone to prepare a clear polymer solution from which a thermoplastic, soluble polyimide was recovered.

EXAMPLE 7 Preparation of a thermoplastic diether polyimide

Using the procedure and apparatus of Example 2, 2.05 g (0.005 moles) of the Bisphenol A diether diamine of Example 3 charged with 50 g of N-methyl pyrrolidone was reacted. 2.55 g (0.005 moles) of the sulfonyl diether dianhydride of Example 2 charged with 40 g of N-methyl pyrrolidone for 2 hours under reflux to remove the water of the condensation reaction and then for 3 hours at 195º-198°C under reflux to complete the reaction. A thermoplastic polyimide was recovered having a Tg of 220°C.

EX.AMPLE 8

Preparation of a thermoplastic polyimide The procedure and apparatus of Example 2 were used to carry out the reaction of 3.89 g (0.01 moles) of 4,4'[bis- (p-aminophenoxy)]biphenyl charged with 50 g of N-methyl pyrrolidone and 5.42 g (0.01 moles) of the sulfonyl diether dianhydride of Example 2 charged with 114.94 g of N-methyl pyrrolidone. The reaction was carried out for 2 hours under reflux to remove the water produced during the condensation reaction and continued for 3 additional hours at 195° to 198°C under reflux. A clear polymer reaction solution was prepared from which a thermoplastic polyimide having a Tg of 217°C was recovered.

EXAMPLE 9 This example illustrates the preparation of a thermo- plastic polyimide by the reaction of a diether-containing diamine with a mixture of dianhydrides including a diether-containing dianhydride.

Reaction A Into a 500 ml, three neck round bottom flask equipped with a mechanical stirrer, nitrogen inlet, heating mantle, thermometer and distillation head is charged 40 g of N-methyl pyrrolidone followed by 14.63 g (0.0325 moles) of bis [4-(p-aminophenoxy)phenyl] sulfone while maintaining a blanket of nitrogen over the reactants and the mixture is agitated until all of the diamine has dissolved. The reactor is then charged with 2.84 g (0.013 moles) of pyromellitic dianhydride over a period of 2-3 minutes. The anhydride is washed in with 20 g of N-methyl pyrrolidone and then stirred at 25ºC for two hours. At this time, 115 g of N-methyl- pyrrolidone are added to the reactor followed by 10.0 g (0.0195 moles) of 4,4'-bis(3,4-dicarboxyphenoxy)- diphenylsulfide dianhydride and then an additional 35 g of N-methyl pyrrolidone. The reaction mixture is then stirred at 30°C for two and one-half hours at 30°C. A catalytic amount, 0.1 g, of p-toluenesulfonic acid is then added to the reaction mixture and the mixture is heated to its distillation temperature over a period of 90 minutes while a vigorous flow of nitrogen is used to blanket the reaction mixture. Approximately 15 ml of distillate are collected over a thirty minute period. The reaction mixture is then allowed to cool and a moderately viscous, black solution is obtained. This polymer solution is then diluted with 150 g of N-methyl pyrrolidone, filtered, and then added to a large quantity of methanol with vigorous agitation to precipitate the polymer. The precipitated polymer is recovered by filtration and then dried. A tan color polyimide polymer is obtained which is soluble in N-methyl pyrrolidone and fusible. Thus a fusible, soluble polyimide is prepared based upon 60 mole percent of a diether-containing aromatic dianhydride and 40 mole percent of a nondiether-containing dianhydride.

Reaction B Using the procedure and apparatus of Reaction A of this Example, 14.63 g (0.0325 moles) of sulfonyl diether diamine is reacted with 3.33 g (0.0065 moles) of 4,4'-bis- (3,4-dicarboxyphenoxy)diphenyl sulfide dianhydride followed by reaction with 8.54 g (0.026 moles) of 3,3'4,4'-benzo- phenonetetracarboxylic acid dianhydride.

At the completion of the reaction, a moderately viscous black solution is obtained from which a tan color polyimide is recovered in the jsame manner described above. The polyimide polymer is soluble and fusible. A fusible, soluble polyimide is thus prepared based on 20 mole percent of a diether-containing dianhydride and 80 mole percent of a nondiether-containing dianhydride.

EXAMPLE 10

Preparation of a polyamide-acid that is readily convertible to a thermoplastic polyimide

The apparatus of Example 9 was used in this Example. Reaction A A mixture of 4.1g (0.01 moles) of the bisphenol A diether diamine of Example 4 and 20g of N-methyl pyrrolidone were charged to the reactor under a nitrogen blanket and agitated until a clear solution was obtained. Then 5.1g (0.01 moles) of the sulfide diether dianhydride of Example 1 with 22g of N-methyl pyrollidone were charged tothe reactor while agitating the reaction mixture gently. Cooling medium was applied to bring the reaction temperature to room temperature and this temperature was maintained for 1 hour. The reaction mixture was then heated to 30°C and this temperature was maintained while the reaction was continued for 2 hours. The heat was shut off and the reaction mixture was allowed to cool overnight to room temperature at which time the agitation was shut off. The polymer solution was filtered and then portions thereof were applied to a series of glass slides.

The coated glass slides were cured in an oven for 1 hour at 100°C then 1 hour at 150°C, 1 hour at 220°C, and finally 1 hour at 250°C.

After removing from the oven and cooling, the resin coating was found to be tenaciously bonded to the glass slides. The cured resin, however, was also found to be soluble in N-methyl pyrrolidone. Reaction B Using the procedure described for Reaction A, 4.049g (0.01 moles) of the sulfide diether diamine of Example 4 and 5.1g (0.01 moles) of the sulfide diether dianhydride of Example 1 were reacted.

The cured resin was found to tenaciously bond to glass slides and was soluble in N-methyl pyrrolidone.

EXAMPLE 11

This example illustrates that the reaction of certain diether-containing diamines and diether-containing dianhydrides will not result in the preparation of polyimides which are soluble.

Reaction A Using the procedure and apparatus of Example 2, 1.84g (0.005 moles) of 4,4'-bis(aminophenoxy)biphenyl were charged along with 30g of N-methyl pyrrolidone to the reactor and agitated to get a clear solution. Then 2.55g (0.005 moles) of the sulfide diether dianhydride of Example 1 along with 30 parts of N-methyl pyrrolidone were charged to the reactor under a nitrogen blanket. 0.005 parts of p-toluene sulfonic acid was added as a catalyst. When the temperature of the reaction reached 192°C, two phase were observed in the reactor. The temperature of the system was increased to the boiling point of the solvent but the solid phase did not redissolve. Heating was then stopped and the precipitated reaction products was discarded. Reaction B Using the procedure and apparatus of Example 2, 1.89g (0.00395 moles) of 4,4'-bis(3"',4"'-dicarboxyphenoxy)diphenyl dianhydride and 1.5g (0.00395 moles) of 4,4'bis (p-aminophenoxy)biphenyl were reacted in 256 g of N-methyl pyrrolidone. When the temperature of the reaction mass was raised to about 200°C, the reaction mass separated into two phases and the solid phase did not redissolve upon further heating. The reaction was then stopped and the two phase reaction mixture was discarded. Reaction C Using the procedure and apparatus of Example 2, 4.0496g (0.01 moles) of 4,4'-bis (p-aminophenoxy)diphenyl sulfide charged with 50g of N-methyl pyrrolidone was reacted with 4.78g (0.01 moles) of 4,4'-bis(3",4"-dicarboxyphenoxy)- dipheyl dianhydride charged with 113.64g of N-methyl pyrrolidone under a nitrogen blanket in the presence of 0.025g of p-toluene sulfonic acid. When the reaction temperature reached about 202°C, the reaction mixture separated into two phases and the solid phase did not redissolve upon further heating. The reaction was then stopped and the reaction mixture was discarded.

The results of these three experiments show the unpredictability of being able to prepare fusible, soluble polyimides by the reaction of diether dianhydrides and diether diamines and thus the importance of the choice of the diether diamine and diether dianhydride reactants.

In Reaction A, the sulfide diether dianhydride suitable for use as a reactant in Example 1 for the preparation of a thermoplastic, soluble polyimide was reacted with a biphenyl diether diamine which was demonstrated in Example 8 to also be suitable as a reactant for preparing a soluble, fusible polyimide. However, in this experiment, an insoluble product was obtained.

In Reaction B and Reaction C, similar findings were made. The biphenyl diether dianhydride and biphenyl diether diamine reactants used in Reaction B which resulted in the preparation of an insoluble polyimide were found to be reactants suitable for preparing soluble, fusible polyimides in Example 3 and Example 8, respectively, and the reactants of Reaction C were found to be suitable when used in Example 3 and Example 5 respectively.

Claims

WHAT IS CLAIMED IS:

1. A polyimide composition and a polyamide-acid composition which is readily convertible to the polyimide composition which contains at least about 20 mole percent of a residue of the formula

or a mixture thereof; and at least about 50 mole percent of a residue having the formula

or a mixture thereof; wherein Y is a divalent residue of an aromatic diether diamine and has the formula

where G is a substituted or unsubstituted group of the formula

where E is -S- , - - , linear or branched alkylene or

alkenylene of 1 to 8 carbon atoms, or where R and R¹

are the same or different lower alkyl, lower alkenyl or substituted or unsubstituted aryl groups of 6 to about 24 carbon atoms;

A is a tetravalent residue of an aromatic diether dianhydride or other functionality which can generate the dianhydride residue in situ and has the formula

where K is a substituted or unsubstituted group of the formula

where W is -O-, -S-, - -, linear or branched alkylene or

alkenylene of 1 to 8 carbon atoms, or - where R and R¹ are

as hereinabove defined; and m and m' are each 0 or 1 with the proviso that m is 1 when m' is 0 or when m' is 1 and W is -S-, and m' is 1 when m is 0 or when m is 1 and E is -S-.

2. The composition of Claim 1 which contains recurring structural units of the general formulae:

wherein k and k' are the same or different positive integers of one or more and represent the number of different polymers blocks in the composition, and r and r' are the same or different positive integers greater than one and represent the number of times the structural unit is repeated in the polymeric chain.

3. The composition of Claim 2 wherein r and r' have values of 10 to 10,000 or greater.

4. The composition of Claim 1 wherein W is -S-.

5. The composition of Claim 1 wherein W is

6. The composition of Claim 1 wherein E is

7. The composition of Claim 1 wherein E is

8. The composition of Claim 1 wherein the aromatic diether dianhydride is bis-[p-(3,4-dicarboxyphenoxy)- phenyl]sulfide dianhydride and the aromatic diether diamine is 4,4'-bis-(p-aminophenoxy)diphenyl sulfone.

9. The composition of Claim 1 which additionally contains at least ten mole percent of a residue having the formula

-

or

or mixtures thereof; wherein B is a divalent residue of a nondiether- containing diamine which is selected from the group consisting of aliphatic and cycloaliphatic groups of 2 to about 20 carbon atoms; heterocyclic groups of 6 to about 20 carbon atoms including at least one hetero atom selected from -N-, -S- and -O-; polyoxyalkylene groups of about 4 to about 500 carbon atoms and aromatic groups of 6 to about 40 carbon atoms; and combinations thereof;

D is a tetravalent residue of a nondiether-containing tetracarboxylic acid anhydride which is selected from the group consisting of substituted or unsubstituted aliphatic groups of 4 to about 40 carbon atoms, heterocyclic groups of 4 to about 40 carbon atoms including at least one hetero atom selected from -N-, -S-, and -O-, aromatic groups of 6 to about 40 carbon atoms, and combinations thereof.

10.. The composition of Claim 9 wherein B and D are each the same or different aromatic groups of 6 to about 40 carbon atoms.

11. The composition of Claim 9 which additionally contains: up to about 50 mole percent recurring structural units of the general formulae:

or up to about 80 mole percent recurring structural units of the formulae:

or up to about 40 mole percent recurring structural units of the formulae:

wherein j and j', i and i' and h and h' are the same or different positive integers of one or more and represent the number of different polymer blocks in the composition, and s and s', t and t' and u and u' are the same or different positive integers greater than one and represent the number of times the structural unit is repeated in the polymeric chain.

12. The composition of Claim 11 wherein s and s', t and t' and u and u' have values of 10 to 10,000 or greater.

13. A method for preparing a polyimide which comprises reacting at least 20 mole percent of an aromatic diether dianhydride with at least 50 mole percent of an aromatic diether diamine for a period of time necessary to remove the water produced in the reaction and thereafter recover the resultant polyimide, said diamine having the formula H₂N-Y-NH₂ wherein Y is a divalent residue which has the formula

where G is a substituted or unsubstituted group of the formula

where E is -S-, -, linear or branched alkylene or

alkenylene of 1 to 8 carbon atoms, or - where R and R¹ are

the same or different lower alkyl, lower alkenyl or substituted or unsubstituted aryl group of 6 to about 24 carbon atoms; and said dianhydride having the formula

wherein A is a tetravalent residue which has the formula

where K is a substituted or unsubstituted group of the formula

where W is -O-, -S-, - -, linear or branched alkylene or

alkenylene of 1 to 8 carbon atoms, or - where R and R¹ are

14. The method of Claim 13 wherein the reaction is carried out in a solvent in which the reactants and the reaction products are soluble.

15. The method of Claim 14 in which the solvent is a chlorinated hydrocarbon, a dipolar aprotic solvent or a combination thereof.

16. The method of Claim 13 wherein W is -S-,

17. The method of Claim 13 wherein W is

18. The method of Claim 13 wherein E is

19. The method of Claim 13 wherein E is

20. The method of Claim 13 wherein the aromatic diether dianhydride is bis-[p-(3,4-dicarboxyphenoxy)- phenyl]sulfide dianhydride and the aromatic diether diamine is 4,4'-bis-(p-aminophenoxy)diphenyl sulfone.

21. The method of Claim 13 wherein the reactants also include at least 10 mole percent of a nondiether-containing diamine or a nondiether-containing dianhydride or a mixture of such diamine and dianhydride, such diamine having the formula

NH₂-B-NH₂ , wherein B is a diavalent residue selected from the group consisting of aliphatic and cycloaliphatic groups of 2 to about 20 carbon atoms; heterocyclic groups of 6 to about 20 carbon atoms including at least one hetero atom selected from -N-, -S- and -O-; polyoxyalkylene groups of about 4 to about 500 carbon atoms and aromatic groups of 6 to about 40 carbon atoms; and combinations thereof; such dianhydride having the formula

D is a tetravalent residue of a nondiether-containing tetracarboxylic and anhydride which is selected from the group consisting of substituted or unsubstituted aliphatic groups of 4 to about 40 carbon atoms, heterocyclic groups of tf to .about 40 carbon aφms including at least one hetero atom selected from -N-, -S-, and -O-, aromatic groups of 6 to about 40 carbon atoms, and combinations thereof.

22. A method of preparing a polyamide acid which is readily convertible into a polyimide which comprises reacting at least 20 mole percent of an aromatic diether dianhydride with at least 50 mole percent of an aromatic diether diamine at a temperature of up to about 100°C for a period of time necessary to prepare the polyamide acid and thereafter recovering the polyamide acid, said diamine having the formula

H₂N-Y-NH₂ wherein Y is a divalent residue which has the formula

where G is a substituted or unsubstituted group of the formula

where E is -S-, , linear or branched alkylene or

alkenylene of 1 to 8 carbon atoms, or where R and R¹ are

the same or different lower alkyl, lower alkenyl or substituted or unsubstituted aryl groups of 6 to about 24 carbon atoms; and said dianhydride having the formula

wherein A is a tetravalent residue which has the formula

where K is a substituted or unsubstituted group of the formula

where W is -O-, -S-, - -, linear or branched alkvlene or

alkenylene of 1 to 8 carbon atoms, or where R and R¹ are

as hereinabove defined; and m and m' are each O or 1 with the proviso that m is 1 when m' is O or when m' is 1 and W is -S-, and m' is 1 when m is 0 or when m is 1 and E is -S-.

23. The method of Claim 21 wherein the reactants also include at least 10 mole percent of a nondiether-containing diamine or a nondiether-containing dianhydride or a mixture of such diamine and dianhydride, such diamine having the formula

NH₂-B-NH₂ wherein B is a divalent residue selected from the group consisting of aliphatic and cycloaliphatic groups of 2 to about 20 carbon atoms; heterocyclic groups of 6 to about 20 carbon atoms including at least one hetero atom selected from -N-, -S- and -O-; polyoxyalkylene groups of about 4 to about 500 carbon atoms and aromatic groups of 6 to about 40 carbon atoms; and combinations thereof; such dianhydride having the formula

D is a tetravalent residue selected from the group consisting of substituted or unsubstituted aliphatic groups of 4 to about 40 carbon atoms, heterocyclic groups of 4 to about 40 carbon atoms including at least one hetero atom selected from -N-, -S-, and -O-, aromatic groups of 6 to about 40 carbon atoms, and combinations thereof.

24. The polyimide composition of Claim 1 disposed on a substrate.

25. The composition of Claim 24 wherein the substrate comprises a semiconductor device.

26. The composition of Claim 24 wherein the substrate comprises silicon dioxide, silicon nitride, aluminum nitride or conductive metal.

27. The composition of Claim 24 wherein the substrate comprises fibers or filaments of carbon, glass, metal, ceramics, a polyimide, and fabric prepared therefrom.

28. The composition of Claim 24 wherein the substrate comprises a non-metallic article.

29. The composition of Claim 28 wherein the substrate is a thermoplastic polymer.

30. A method for protecting a semiconductor device which comprises applying to the surface thereof a polyimide composition according to Claim 1, opening holes in the polyimide composition layer, attaching one or more wires to said semiconductor at such exposed sites and heating to cause the polyimide composition to flow into said holes and around said wires.

31. A method for protecting a semiconductor device which comprises applying to the surface thereof a polyimide composition according to Claim 9, opening holes in the polyimide composition layer, attaching one or more wires to said semiconductor at such exposed sites and heating to cause the polyimide composition to flow into said holes and around said wires.