Abstract: An addition type polyimide resin raw material composition having high heat resistance and high corrosion resistance comprising a tetracarboxylic anhydride and/or tetracarboxylic diester compound, diamine compound and exo-3,6-epoxy-1,2,3,6-tetrahydrophthalic anhydride and/or exo-3,6-epoxy-1,2,3,6-tetrahydrophthalic monoester compound; a composition containing a prepreg; a fiber-reinforced polyimide composite prepreg, coating material and paint using them; and a curing method thereof.

Abstract: A photosensitive resin composition comprising;(A) a polyimide precursor containing an acrylic or methacrylic group;(B) a tertiary amine compound represented by the general formula: ##STR1## wherein R.sup.6 is a monovalent organic group having 3 or less carbon atoms, R.sup.7 is a divalent organic group having 3 or less carbon atoms, and R.sup.8 is a hydrogen atom or a methyl group; and(C) at least one of a photopolymerization initiator and a sensitizer.This composition has a sufficient sensitivity even when thick films are formed, has a superior developability in an aqueous alkali solution, and is suited for the formation of polyimide patterns.

Abstract: Copolyetherimides are prepared by the reaction of an alkali metal salt of a dihydroxyaromatic compound with a bis(substituted phthalimide) and a third compound which may be a substituted aromatic ketone or sulfone or a macrocyclic polycarbonate or polyarylate oligomer. The reaction takes place the in presence of a solvent and a phase transfer catalyst having high thermal stability, such as a hexaalkylguanidinium halide. Random or block copolymers may be obtained, depending on the reaction conditions.

Abstract: An aromatic polyimide precursor composition advantageously employable for the production of an amorphous aromatic polyimide film having Tg of 300.degree. C. or higher is composed of an aromatic tetracarboxylic acid component and an aromatic diamine component which are dissolved in an organic solvent, in which at least 60 mol. % of the aromatic tetracarboxylic acid component is 2,3,3',4'-bi-phenyltetracarboxylic acid, its monoester or diester of a primary alcohol, or their mixture, and at least 55 mol. % of the aromatic diamine component is 4,4'-diaminodiphenyl ether.

Abstract: Novel polyimide copolymers containing ether linkages were prepared by the reaction of an equimolar amount of dianhydride and a combination of diamines. The polyimide copolymers described herein possess the unique features of low moisture uptake, dimensional stability, good mechanical properties, and moderate glass transition temperatures. These materials have potential application as encapsulants and interlayer dielectrics.

Abstract: A method for synthesizing 1,4-bis(4-aminophenoxy)naphthalene and a series of polyamides, polyimides and copoly(amide-imide)s derived from the said compound is disclosed. These polymers possess excellent thermal stability and mechanical strength.

Abstract: A rigid, aromatic polyimide composition prepared using a solution imidization process from an aromatic tetracarboxylic dianhydride and a diamine which is greater than 60 mole % to about 85 mole % p-phenylene diamine and 15 mole % to less than 40 mole % m-phenylene diamine exhibits exceptional tensile properties and thermal oxidative stability.

Abstract: In a method of synthesis of polybenzoxazole and polybenzothiazole precursors, a dicarboxylic acid or a dicarboxylaic acid ester is reacted with a bis-o-aminophenol or bis-o-aminothiophenol in a suitable solvent in the presence of an activating reagent having the following structure: ##STR1##

Abstract: Polyimide copolymers were prepared by reacting different ratios of 3,4'-oxydianiline (ODA) and 1,3-bis(3-aminophenoxy)benzene (APB) with 3,3',4,4'-biphenylcarboxylic dianhydride (BPDA) and endcapping with an effective amount of a non-reactive endcapper. Within a narrow ratio of diamines, from .sup..about. 50% ODA/50% APB to .sup..about. 95% ODA/5% APB, the copolyimides prepared with BPDA have a unique combination of properties that make them very attractive for various applications. This unique combination of properties includes low pressure processing (200 psi and below), long term melt stability (several hours at 390.degree. C.), improved toughness, improved solvent resistance, improved adhesive properties, and improved composite mechanical properties.

Abstract: A solvent-soluble siloxane polyimide comprising a copolymer obtained by reaction of a diamine compound mixture comprising a diaminopolysiloxane and an alicyclic diamine with an aromatic tetracarboxylic acid anhydride, followed by polyimidization reaction of the resulting polyamic acid forms a heat-resistant adhesive by adding an epoxy resin, a diamine-based curing agent and an organic solvent thereto, The formed adhesives show a distinguished heat-resistant adhesiveness when the resulting siloxane polyimide soluble in ordinary organic solvents is used as a main component of the adhesive for bonding between a base material and a copper foil of a flexible printed substrate. By further addition of a fluorinated resin to the heat-resistant adhesive, the adhesiveness can be more improved.

Abstract: A process for inducing pre-tilt in alignment of a liquid crystal medium comprising exposing at least one optical alignment layer, comprising anisotropically absorbing molecules and hydrophobic moieties, to polarized light; the polarized light having a wavelength within the absorption band of said anisotropically absorbing molecules; wherein the exposed anisotropically absorbing molecules induce alignment of the liquid crystal medium at an angle + and -.theta. with respect to the direction of the polarization of the incident light beam and along the surface of the optical alignment layer, and induce a pre-tilt at an angle .PHI. with respect to the surface of the optical alignment layer and applying a liquid crystal medium to said optical alignment layer, is described. The invention also is directed to liquid crystal display elements made by the process of the invention and to novel polyimide compositions that are useful as optical alignment layers in the invention.

Abstract: This invention provides a polyimide precursor solution having high concentration and low viscosity and a production process thereof, and polyimide coatings and films having excellent physical properties obtained therefrom and a production process thereof. Particularly, it relates to a polyimide precursor solution which contains a salt of a specific diamine with a specific tetracarboxylic acid, as its solute; to a process for the production of the polyimide precursor solution, which comprises allowing 1 mole of a specified diamine to react with 0.3 to 0.9 mole of a specific tetracarboxylic acid dianhydride, thereby obtaining a diamine, and subsequently adding 0.95 to 1.

Abstract: A photosensitive resin composition comprising, as its main ingredient, a poly(amic acid) resin constituted of a diamino compound represented by formula: ##STR1## and optionally used other diamino compound and a tetracarboxylic acid dianhydride as its constituent monomers and/or a poly(amic acid) ester resin obtained by esterifying said poly(amic acid) resin and/or a polyimide resin obtained by a dehydrating or alcohol-eliminating ring-closure reaction of said poly(amic acid) resin or poly(amic acid) ester resin has an excellent developability and a high film strength and can form a relief patter of low thermal expansion.

Abstract: A new diamine, 2,2'-dimethyl-4,4'-bis(4-aminophenoxy)-biphenyl was synthesized and used to prepare high performance engineering plastics by polycondensation. The new diamine as shown in the following formula has a noncoplanar 2,2'-disubstituted biphenylene and a flexible aryl units: ##STR1## The engineering plastics disclosed in the present invention includes polyamides, polyimides and poly(amide-imide)s.

Abstract: Polyetherimide polymers prepared from monomers containing indane moieties are disclosed. The high molecular weight indane polyetherimides are transparent, ductile, and exhibit high glass transition temperatures (>200.degree. C.). In addition, the polyetherimides are thermally stable at high temperatures and exhibit good optical properties making them useful in high temperature processing applications, in the fabrication of optoelectronics devices, and in optical applications.

Abstract: Aromatic polyether polymers, illustrated by polyethersulfones, polyetherketones and polyetherimides, are prepared by a phase transfer catalyzed reaction between a salt of at least one dihydroxyaromatic compound and at least one substituted aromatic compound such as bis(4-chlorophenyl) sulfone, bis(4-chlorophenyl) ketone or 1,3-bis?N-(4-chlorophthalimido)!benzene, in a monoalkoxybenzene such as anisole as diluent and in the presence of a phase transfer catalyst, preferably a hexaalkylguanidinium salt.

Abstract: A polyamideamic acid resin prepolymer represented by formula A having isophorone diamine as one of monomers, ##STR1## in which k, l, m and n are integer of 1 or more, respectively, and ##EQU1## --R-- is at least one group selected from the group consisting of ##STR2## --R'-- is a cis- and trans-conformational mixture of ##STR3## high heat resistant polyamideimide foam produced therefrom, and processes for producing them are disclosed.

Abstract: A process is disclosed for preparing a polyamide by polymerizing a diacid and a diamine, aminocarboxylic acid or lactam in the presence of excess of either acid or amine such that the ratio of acid to amine end groups or the ratio of amine end groups to acidend groups in the polymer is at least 2.0:1.0.

Abstract: A sliding material and a heat resistant filament which primarily comprises a liquid crystal polyimide, a liquid crystal polyamide or a liquid crystal polyamide-imide copolymer having at least one recurring structural unit selected from the formula (1) and the formula (2) and is excellent in heat resistance, mechanical characteristics and other fundamental properties of polyimides, and relates to significant improvement of heat-resistance by heat-treating the sliding material, the filament and the molded items. The liquid crystal polyamide-imide copolymer which comprises in a polymer molecule 0.05.about.0.95 mole ratio of the recurring structural units of the formula (1) and 0.95.about.0.

Abstract: 18.4 grams of 4,4'-(hexafluoroisopropyridine)diphthalic acid dianhydride and 7.5 grams of 1,4-phenylenediamine dihydrochloride are mixed in a solvent consisting of 80 ml of N-methyl-2-pyrrolidone and 20 ml of dichlorobenzene and are heated at an argon atmosphere to raise its temperature from a room temperature to 170.degree. C. slowly and to be reacted for five hours while an azeotropic dihydration of water which is generated at 170.degree. C. is conducted. After the reaction is completed, a reaction product is precipitated in methanol, the precipitate is washed with methanol and dried at 80.degree. C. FIG. 1 shows the infrared spectra of the reaction product.

Abstract: A diamine which is useful in preparing a new flexible polyamide and polyimide with an aromatic dicarboxylic acid and a tetracarboxylic dianhydrides, respectively, has a general formula as follows: ##STR1## wherein R.sub.1 is a proton (--H) or methyl (--CH.sub.3) and n is an integer ranging from 1 to 4. These polyamide and polyimide exhibit good mechanical performance and processability.

Abstract: The morphology of multidimensional oligomers is combined with the inclusion of charge carrier linkages within the oligomer arms to produce oligomers that are useful for preparing conductive or semiconductive composites, if suitably doped. The Schiff base linkages are prepared by the condensation of aldehydes and amines. The oligomers can be blended, and either the oligomers or their blends can be prepregged.

Abstract: The present invention relates to a new polyesterimide of the type containing ester repeat functional groups E=--CO--O--, imide repeat functional groups I: ##STR1## and at least one chromophore, characterized in that it contains a quantity of recurrent amide functional groups capable of ring closure to imides which is smaller than or equal to 5 mol % relative to the sum of the imide functional groups and of the amide functional groups capable of ring closure to imides, which are present, and in that the polymerization functional groups consist essentially of E functional groups.This polyesterimide is preferably free from amide functional groups capable of ring closure to imides.One of the processes for obtaining this polyesterimide constitutes another subject-matter of the invention.Such a polymer is advantageously capable of behaving like a material that is transparent and/or active in nonlinear optics.

Abstract: A sulfonated dicarboxylic acid and a diaromatic carbonate are reacted by a solution process to form a sulfonated aromatic diester such as diphenyl sodium 5-sulfoisophthalate. The sulfonated aromatic diester is reacted with an aromatic polymer precursor mixture such as bisphenol A and diphenyl carbonate, polymer or combination thereof, at a temperature above the melting point of the polymer or a member of the aromatic polymer precursor to form a randomly positioned sulfonated aromatic moiety in a polymer chain of a thermoplastic non-crosslinked aromatic polymer such as a linear polycarbonate.

Abstract: This invention is directed to a polyimide film useful as use applications for electronic materials; a liquid crystal aligning film using the same; a liquid crystal display element provided with the liquid crystal aligning film; and a polyamic acid used as a raw material of the polyimide constituting the polyimide film.The polyimide used for preparing the above polyimide films, consists of a diamine component, the 50% by mol or more based upon the total diamine, of which is a diamine having a core structure having no polar group such as 1,2-bis(4-(4-aminobenzyl)phenyl)ethane, 1,6-bis(4-(4-aminobenzyl)phenyl)hexane, 1,1-bis(4-(4-aminobenzyl)phenyl)heptane, etc., and a tetracarboxylic acid dianhydride, and if necessary, an aminosilicon compound, is used as a liquid crystal aligning film.

Abstract: A process for making polyimide composition comprising reacting at least one diamine, at least one tetracarboxylic diacid diester, selected phosphoramide and at least one base catalyst to form at least one polyimide compound, said reaction carried out at a temperature from about 20.degree. C. to about 60.degree. C. and wherein the molar ratio of diamine:tetracarboxylic diacid diester:phosphoramide:base catalyst is in the range of 0.8-1.2:1:2.5-4.0:2.5-4.0.

Abstract: A process for producing a polyimide composition by reacting at least one polyamic acid or at least one polyamic ester or a mixture of at least one polyamic acid and at least one polyamic ester with a selected phosphoramide in the presence of at least one base catalyst to from a polyimide composition.

Abstract: There are provided a polyamic acid obtainable by reacting a diamine compound of the formula (1) ##STR1## wherein R.sup.1 is an alkyl group having 1 to 12 carbon atoms, a haloalkyl group having 1 to 12 carbon atoms or a halogen atom, each of X and Y is independently a divalent linking group,with a tetracarboxylic acid dianhydride; a polyimide obtainable by dehydrating and ring-closing the above polyamic acid; and a liquid crystal aligning agent containing the above polyamic acid and/or the above polyimide.

Abstract: A method for producing poly-o-hydroxy amides by conversion of an activated dicarboxylic acid derivative with a bis-o-aminophenol. A solution of the activated dicarboxylic acid derivative is added to a solution of the bis-o-aminophenol in a lactone, and a tertiary amine is added to the resulting mixture, wherein the lactone has the following structure: ##STR1## where A is--(CR.sup.1 R.sup.2).sub.m --or--(CR.sup.3 R.sup.4).sub.n --NR.sup.5 --,R.sup.1 to R.sup.5 are independent of one anotherR.sup.1 and R.sup.2 are hydrogen, alkyl with 1 to 7 carbon atoms (linear or branched), --CO(CH.sub.2).sub.p CH.sub.3, or --COO(CH.sub.2).sub.p CH.sub.3, with p=0 or 1,R.sup.3 and R.sup.4 are hydrogen or alkyl with 1 to 3 carbon atoms (linear or branched),R.sup.5 is hydrogen or methyl,m is a whole number from 2 to 11, andn is a whole number from 1 to 3.

Abstract: Provided are photosensitive resin compositions comprising a polyamic compound having, at each terminal thereof, a specific actinic ray-sensitive functional group which has substituent groups each having a photopolymerizable carbon-carbon double bond, a photosensitive auxiliary having a photopolymerizable functional group and a solvent. The photosensitive resin compositions of the invention are excellent in resist properties such as sensitivity and good in storage stability and can provide a film small in residual stress.

Abstract: Disclosed is a process which comprises reacting a polyimide precursor with borane. Also disclosed is a thermal ink jet printhead containing a layer comprising the product of this reaction.

Abstract: The present invention relates to a process of producing a polyimide-type copolymer, to a thin layer forming agent, to a liquid crystal alignment layer and to processes of producing thin layer formation agents and liquid crystal alignment layers. More specifically, this invention relates to a polyamic acid block copolymer, a polyimide block copolymer, a polyimide-polyamic acid block copolymer, a thin layer forming agent comprised of a polyimide-type block copolymer, and a liquid crystal alignment layer comprised of a polyimide-type block copolymer and processes of their production.

Abstract: The present invention relates generally to a new adhesive comprising a vinyl containing siloxane-containing polyimide for use in TSM capping of electronic package assemblies with adhesive capability of providing a seal band width of less than 4mm and even less than 2mm, solubility in non-toxic and environmentally safe solvents and durable adhesive properties and to a method for making the polyimides, a method for using the polyimides to make electronic packages and electronic packages made using the adhesive. The preferred vinyl-containing siloxane containing polyimide is a block type polymer containing blocks of a dianhydride-aromatic diamine oligomeric reaction product joined by non-vinyl/vinyl containing siloxane diamine forming links.

Abstract: In the process of the present invention, a non-polar, aprotic solvent is removed from an oligomer/polymer solution by freeze-drying in order to produce IPNs and semi-IPNs. By thermally quenching the solution to a solid in a short length of time, the size of the minor constituent-rich regions is greatly reduced as they are excluded along with the major constituent from the regions of crystallizing solvent. The use of this process sequence of controlling phase morphology provides IPNs and semi-IPNs with improved fracture toughness, microcracking resistance, and other physical-mechanical properties as compared to IPNs and semi-IPNs formed when the solvent is evaporated rather than sublimed.

Abstract: In a process for the preparation of poly-o-hydroxyamides and poly-o-mercaptoamides, a bis-o-aminophenol or a bis-o-aminothiophenol is reacted at a temperature of .ltoreq.0.degree. C. with a mixed dianhydride of a dicarboxylic acid and a sulfonic acid with the following structure:E--SO.sub.2 --O--CO--R*--CO--O--SO.sub.2 --Ewhere E is an (optionally substituted) methyl, phenyl, or naphthyl group and R* is the parent body of the dicarboxylic acid.

Abstract: Controlled molecular weight phenylethynyl terminated imide oligomers (PETIs) have been prepared by the cyclodehydration of precursor phenylethynyl terminated amic acid oligomers. Amino terminated amic acid oligomers are prepared from the reaction of dianhydride(s) with an excess of diamine(s) and subsequently endcapped with phenylethynyl phthalic anhydride(s) (PEPA). The polymerizations are carried out in polar aprotic solvents such as N-methyl-2-pyrrolidinone or N,N-dimethylacetamide under nitrogen at room temperature. The amic acid oligomers are subsequently cyclodehydrated either thermally or chemically to the corresponding imide oligomers. Direct preparation of PETIs from the reaction of dianhydride(s) with an excess of diamine(s) and endcapped with phenylethynyl phthalic anhydride(s) has been performed in m-cresol. Phenylethynyl phthalic anhydrides are synthesized by the palladium catalyzed reaction of phenylacetylene with bromo substituted phthalic anhydrides in triethylamine.

Abstract: A liquid crystal aligning agent comprising a polyamic acid containing an aliphatic and/or alicyclic hydrocarbon group and a polyimide containing an aliphatic and/or alicyclic hydrocarbon group; and a liquid crystal display device using the liquid crystal aligning agent. This liquid crystal aligning agent gives a liquid crystal aligning film which has good liquid crystal aligning property and in which pretilt angle can be changed by radiation with a small energy and which is suitable for domain-divided alignment type liquid crystal display having a wide view angle.

Abstract: A polyimide precursor composition, which comprises, a polyamic acid having a repeating unit represented by the following general formula (PA), and at least one kinds of cure accelerator selected from the group consisting of a substituted or unsubstituted nitrogen-containing heterocyclic compound exhibiting an acid dissociation index "pKa" of a proton complex ranging from 0 to 8 in an aqueous solution thereof, or an N-oxide compound of said nitrogen-containing heterocyclic compound (AC1), a substituted or unsubstituted amino acid compound (AC2), and an aromatic hydrocarbon compound or an aromatic heterocyclic compound having a molecular weight of 1,000 or less and two or more hydroxyl groups (AC3): ##STR1## wherein .phi. is a quadrivalent organic group, .phi. is a bivalent organic group, R is a substituted or unsubstituted hydrocarbon group, organosilicic group or hydrogen atom.

Abstract: Photosensitive polyimides (Ps-PIM) materials have been synthesized that belong to three families of Ps-PIM materials. Through the use of precursors, various catalytic compositions with differing photosensitivities are provided. The results are Ps-PIM materials having increased photosensitivities at wavelengths longer than approximately 330 to 350 nm and an associated catalytic system that is insensitive to oxygen. A variety of applications, including use in holographic systems, are improved by the present invention.

Abstract: A dope for cast formation comprising a fluorine including polyimide resin and an organic solvent (P) as main components. The fluorine including polyimide resin has at least one --CF.sub.3 group in the repeating molecular unit. The organic solvent (P) is present during the resin polymerization of the fluorine including polyimide resin. The organic solvent (P) is diethylene glycol dimethyl ether.

Abstract: An angularity enhancement layer in a liquid crystal display, which display comprises a liquid crystal cell, wherein the angularity enhancement layer includes a negative birefringent polyimide layer comprising a plurality of structural units having pendant fluorene groups, said angularity enhancement layer being disposed on at least one surface of said liquid crystal cell. A liquid crystal display can comprise an angularity enhancement construction of the invention which comprises a polyimide layer.

Abstract: An aromatic polyimide having a recurring unit of the formula (I): ##STR1## wherein Ar is a divalent aromatic group having one or two benzene rings which has a sulfonate group of --SO.sub.3 H, --SO.sub.3 M, and --SO.sub.3 N(L).sub.4 on the ring, wherein M is an alkali metal and L is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, is favorably employed in the form of a semipermeable film for gas separation.

Abstract: Disclosed are cosmetic melanins of different colors produced by procedures involving oxidative polymerization of monomeric precursors of melanin and/or co-monomers that enhance substantivity or adherence of the melanins to the skin and hair. Also disclosed are methods for preparing cosmetic melanins and methods for using these compositions topically to produce a natural-appearing tan and to prevent damage to skin caused by UV exposure.

Abstract: Tough, soluble, aromatic, thermoplastic copolyimides were prepared by reacting 4,4'-oxydiphthalic anhydride, 3,4,3',4'-biphenyltetracarboxylic dianhydride and 3,4'-oxydianiline. These copolyimides were found to be soluble in common amide solvents such as N,N'-dimethyl acetamide, N-methylpyrrolidinone, and dimethylformamide allowing them to be applied as the fully imidized copolymer and to be used to prepare a wide range of articles.

Abstract: The present invention provides a film adhesive comprising, as the main constituent, a polyimide resin having a glass transition temperature of 350.degree. C. or lower and soluble in organic solvents, which polyimide resin is obtained by reacting at least one of the following acid components (A) and (B)(A) 4,4'-oxydiphthalic acid dianhydride(B) 3,3',4,4'-biphenyltetracarboxylic acid dianhydride and/or 3,3',4,4'-benzophenonetetracarboxylic acid dianhydridewith at least one of the following amine components (C) and (D)(C) a siloxane compound represented by the following general formula (1) and/or 2,2-bis(4-(4-amino-phenoxy)phenyl)propane ##STR1## wherein R.sub.1 and R.sub.2 are each a bivalent aliphatic (C.sub.1-4) or aromatic group; R.sub.3, R.sub.4, R.sub.5 and R.sub.6 are each a mono-valent aliphatic or aromatic group; and k is an integer of 1-20,(D) bis(aminophenoxy)benzene and/or dimethylphenylene-diamineto give rise to ring closure of imide, as well as a process for producing said film adhesive.

Abstract: The polyimide film of this invention is formed from a polyimide, which is prepared by reacting a diamino compound represented by the general formula (1): ##STR1## wherein X represents a hydrocarbon group having 1 to 20 carbon atoms or a sulfur atom; R represents each independently a halogen atom, a hydrocarbon group having 1 to 6 carbon atoms or a halogen-containing hydrocarbon group having 1 to 6 carbon atoms; a represents each independently an integer of 0 to 4;with a tetracarboxylic dianhydride represented by the general formula (2) ##STR2## wherein Y represents a tetravalent organic group having 2 or more carbon atoms.The polyimide film obtained can be applied favorably to a flexible printed circuit board without adhesion layer, a protective coating for electronic parts and electric wires, or a heat resistant adhesive.

Abstract: A polyimide alignment film based on pyromellitic dianhydride and a bis(4-aminophenoxy) aromatic compound, such as 1,3-bis(4-aminophenoxy)benzene or 1,4-bis(4-aminophenoxy)benzene, providing low tilt angles of from to 2 degrees when used in liquid crystal displays.

Abstract: A process for inducing pre-tilt in alignment of a liquid crystal medium comprising exposing at least one optical alignment layer, comprising anisotropically absorbing molecules and hydrophobic moieties, to polarized light; the polarized light having a wavelength within the absorption band of said anisotropically absorbing molecules; wherein the exposed anisotropically absorbing molecules induce alignment of the liquid crystal medium at an angle + and -.theta. with respect to the direction of the polarization of the incident light beam and along the surface of the optical alignment layer, and induce a pre-tilt at an angle .PHI. with respect to the surface of the optical alignment layer and applying a liquid crystal medium to said optical alignment layer, is described. The invention also is directed to liquid crystal display elements made by the process of the invention and to novel polyimide compositions that are useful as optical alignment layers in the invention.

Abstract: In a process for the preparation of poly-o-hydroxyamides and poly-o-mercaptoamides, a bis-o-aminophenol or a bis-o-aminothiophenol is reacted with a dicarboxylic acid derivative of the following structure: ##STR1## with D=O, S, or NH and where R* is the parent body of the dicarboxylic acid and the groups R.sup.1 through R.sup.4 are H, F, CH.sub.3, or CF.sub.3 (with a maximum of two CH.sub.3 or CF.sub.3 groups).

Abstract: A novel polyimide is soluble in organic solvents and excels in heat resistance. The polyimide comprises 95-40 mol % of the repeating unit represented by the formulas (1) and 60-5 mol % of the repeating unit represented by the formula (2) and has a number average molecular weight of 4,000-200,000: ##STR1## wherein X is --SO.sub.2 -- and/or --C(.dbd.O)--OCH.sub.2 CH.sub.2 O--C(.dbd.O)--, Ar is a divalent group containing aromatic rings, and R is an alkylene group having 1-10 carbon atoms or a group: --CH.sub.2 OC.sub.6 H.sub.4 --, and n is an integer of 1-20.