Abstract: A polyimide film, which is produced from polyamide acid prepared through the reaction of p-phenylenebis(trimellitic acid monoester anhydride), oxydiphthalic acid dianhydride, p-phenylenediamine, and 4,4′-diaminodiphenylether in an organic solvent, and which has a high elastic modulus, a high elongation, a low coefficient of linear expansion which is not quite different from that of copper, and a low coefficient of hygroscopic expansion.

Abstract: A process for the preparation of an oligomeric polyimide comprises: mixing a tetracarboxylic acid, a dianhydride, a partially hydrolysed dianhydride or a mixture thereof with a diamine in a reaction medium comprising greater than 80% by weight water, and heating mixture in said reaction medium at a temperature above 100° C. for a time sufficient to form said oligomeric polyimide.

Abstract: An object of the invention is to provide thermosetting amic acid microfine particles, thermosetting imide microfine particles and crosslinked imide microfine particles of controlled particle shape and size distribution. The invention provides a production technology which comprises mixing a first solution containing a tetracarboxylic anhydride and a C═C bond-containing acid anhydride with a second solution containing a diamine compound, causing precipitation of thermosetting amic acid microfine particles from the resulting mixture, and further producing thermosetting imide microfine particles and crosslinked imide microfine particles from the thermosetting amic acid microfine particles.

Abstract: Plumbing articles made from a thermoplastic resin comprising a poly(biphenyl ether sulfone) and a poly(aryl ether sulfone) comprising bisphenol A residues.

Abstract: Disclosed is a composition comprising a polymer with a weight average molecular weight of from about 1,000 to about 100,000, said polymer containing at least some monomer repeat units with a first, photosensitivity-imparting substituent which enables crosslinking or chain extension of the polymer upon exposure to actinic radiation, said polymer also containing a second, thermal sensitivity-imparting substituent which enables further crosslinking or chain extension of the polymer upon exposure to temperatures of about 140° C.

Abstract: A method for preparing polyamic acid and polyimide of three-dimensional molecular structure such that these polymers are superior in adhesive strength and high-temperature stability while maintaining their inherent thermal resistance and mechanical properties, and thus can be effectively used as an adhesive material for high temperature adhesive tapes suitable for semiconductor assembly.

Abstract: A polyimide for optical communications, which is expressed by the formula (1) where R1 and R2 are independently selected from the group consisting of CF3, CCl3, unsubstituted aromatic ring group and halogenerated aromatic ring group; R3 and R4 are independently selected from the group consisting of Cl, F, I, Br, CF3, CCl3, unsubstituted aromatic ring group and halogenated aromatic ring group; and n is an integer from 1 to 39. The polyimides have a superior heat resistance, and can avoid the increase in optical absorption loss due to a refractive index increase and deterioration of adhesive and coating properties due to weak surface tension of a polyimide film. In addition, use of the polyimides as a material for a core layer of optical waveguides can expand the selection range of material for the cladding layer of the optical waveguide.

Abstract: The present invention provides a liquid crystal display element having an adequate pre-tilt angle for preventing the reverse domain, as well as excellent electrical properties by preparation of the polyamic acid composition for the liquid crystal display element which comprises a polyamic acid A that excels in electrical properties and a polyamic acid B that has side chains, mixed in the ratio A/B of 50/50 to 95/5 (by weight).

Abstract: A polymide useful as an adhesive for semiconductor assemblies having excellent thermal resistance and adhesive strength at high temperatures.

Abstract: A polyimide represented by the following general formula (1); wherein l, m, and n represent not the order of each repeating unit, but the numbers of each repeating unit existing in the molecule, E1 is a photosensitive group, E2 is a group comprising an alkyl group having 2 to 20 carbon atoms, —A(—E1)—, —A(—E2)—, and B each are a divalent organic group, X and Y each are a tetravalent organic group, X, Y, A, B, E1 and E2 may be identical or different among the repeating units, 1 is an integer of 1 or more, m and n each are an integer of 0 or more. The polyimide and polyimide compositions comprising it has thermoreactivity as well as photoreactivity and photosensitivity.

Abstract: Polyimides and the process for preparing polyimides having improved thermal-oxidative stability derived from the polymerization of effective amounts of one or more of the polyamines such as the aromatic diamines, one or more of the tetracarboxylic dianhydrides and a novel dicarboxylic endcap having a formula selected from the group consisting of: wherein R1 is either a radical where R is either hydrogen or an alkyl radical of 1 to 4 carbons, R2 is either OH, NH2, F, or Cl radical, R3 is either H, OH, NH2, F, Cl or an alkylene radical, R4 is either an alkyl, aryl, alkoxy, aryloxy, nitro, F, or Cl radical, and R5 is either H, alkyl, aryl, alkoxy, aryloxy, nitro, F, or Cl radical. The polyimides are useful particularly in the preparation of prepregs and PMR composites.

Abstract: The present invention provides a novel polyimide composition which includes a cinnamoyl group or a derived cinnamoyl group and has photo-reactivity and heat-reactivity inherent to the cinnamoyl group. Further, a novel diamine and an acid dianhydride according to the present invention are materials mainly used for preparing a novel polyimide composition having the cinnamoyl group or the derived cinnamoyl group in a main chain or a side chain.

Abstract: A polyimide for optical communications, which is expressed by the formula (1), a method of preparing the same, and a method of forming multiple polyimide films using the polyimide, wherein the formula (1) is given by X1, X2, X3, A1, A2, B1, B2, B3, D1, D2, E1, E2, Y1, Y2, Y3, Y4, Y5, Y6, Y7, and Y8, are independently selected from the group consisting of hydrogen atom, halogen atom, alkyl group, halogenated alkyl group, aryl group and halogenated aryl group; Z is a simple chemical bond or selected from the group consisting of —O—, —CO—, —SO3—, —S—, —(T)m—, —(OT)m— and —(OTO)m—, wherein T is alkylene or arylene group substituted by at least one of halogen atom and halogenated alkyl group and m is an integer from 1 to 10; and n is an integer from 1 to 39.

Abstract: Dielectric compositions encompassing one or more poly(arylene ether) polymers are provided. The dielectric compositions have the repetitive structural unit: where n=1 to 200, Y and Ar are each a divalent arylene radical, Y derived from bisphenol compounds of general formula HO—Y—OH, Ar derived from difluoro diarylacetylenes and/or ethynylated benzophenones of general formula F—Ar—F and Z is optionally hydrogen, a methyl group or derived from a monofluoro-benzophenone derivative of general formula Z—F. Such poly(arylene ether) polymers are employed with a variety of microelectronic devices, for example, integrated circuits and multichip modules.

Abstract: A polymeric low dielectric constant solution includes a low dielectric constant polymer dissolved in an aromatic aliphatic ether solvent. The polymer preferably is a poly(arylene ether) and the solvent preferably is anisole, methylanisole, phenetole or mixtures thereof. A process for forming a dielectric film on a substrate by spin-coating the polymeric solution is also provided.

Abstract: Polyimide copolymers were obtained containing 1,3-bis(3-aminophenoxy)benzene (APB) and other diamines and dianhydrides and terminating with the appropriate amount of reactive endcapper. The reactive endcappers studied include but should not be limited to 4-phenylethynyl phthalic anhydride (PEPA), 3-aminophenoxy-4′-phenylethynylbenzophenone (3-APEB), maleic anhydride (MA) and nadic anhydride (5-norbornene-2,3-dicarboxylic anhydride, NA). Homopolymers containing only other diamines and dianhydrides which are not processable under conditions described previously can be made processable by incorporating various amounts of APB, depending on the chemical structures of the diamines and dianhydrides used. By simply changing the ratio of APB to the other diamine in the polyimide backbone, a material with a unique combination of solubility, Tg, Tm, melt viscosity, toughness and elevated temperature mechanical properties can be prepared.

Abstract: Terminal-modified imide oligomers with an inherent viscosity of 0.05-1 obtained by reacting 2,3,3′,4′-biphenyltetracarboxylic dianhydride, an aromatic diamine compound and 4-(2-phenylethynyl)phthalic anhydride, and their cured products. There are provided highly practical terminal-modified imide oligomers and their cured products, which cured products have satisfactory heat resistance and mechanical properties.

Abstract: The present invention provides polyimides and co-polyimides that are organosoluble. The polyimides and co-polyimides are prepared from an aromatic diamine having ortho-linked phenylene and pendant tert-butyl group, i.e., 1,2-bis(4-aminophenoxy)-4-tert-butyl-benzene, or its mixture with other diamines, and a mixture of dianhydrides that containing at least one dianhydride selected from s-BPDA, DSDA, ODPA, 6FDA and other diether-dianhydrides.

Abstract: Polyimides and the process for preparing polyimides having improved thermal-oxidative stability derived from the polymerization of effective amounts of one or more of the polyamines such as the aromatic diamines, one or more of the tetracarboxylic dianhydrides and a novel dicarboxylic endcap having a formula selected from the group consisting of: wherein R1 is either a radical where R is either hydrogen or an alkyl radical of 1 to 4 carbons, R2 is either OH, NH2, F, or Cl radical, R3 is either H, OH, NH2, F, Cl or an alkylene radical, R4 is either an alkyl, aryl, alkoxy, aryloxy, nitro, F, or Cl radical, and R5 is either H, alkyl, aryl, alkoxy, aryloxy, nitro, F, or Cl radical. The polyimides are useful particularly in the preparation of prepregs and PMR composites.

Abstract: Disclosed is a composition which comprises a polymer containing at least some monomer repeat units with water-solubility- or water-dispersability-imparting substituents and at least some monomer repeat units with photosensitivity-imparting substituents which enable crosslinking or chain extension of the polymer upon exposure to actinic radiation, said polymer being of the formula wherein x is an integer of 0 or 1, A is one of several specified groups, such as B is one of several specified groups, such as or mixtures thereof, and n is an integer representing the number of repeating monomer units. In one embodiment, a single functional group imparts both photosensitivity and water solubility or dispersability to the polymer. In another embodiment, a first functional group imparts photosensitivity to the polymer and a second functional group imparts water solubility or dispersability to the polymer.

Abstract: The present invention provides a process for preparing an optical alignment layer for aligning liquid crystals and liquid crystal displays comprising exposing polyimide layers with polarized light. The invention further describes optical alignment layers, liquid crystal displays incorporating optical alignment layers and novel polymer compositions within the class of polyimide, polyamic acids and esters thereof.

Abstract: Polyether polymers such as polyetherimides are prepared by a two-step reaction. The first step is the reaction between an alkali metal salt of a dihydroxy-substituted aromatic hydrocarbon, such as bisphenol A disodium salt, and a substituted aromatic compound such as 1,3-bis[N-(4-chlorophthalimido)]benzene, the alkali metal salt being employed in an amount less than stoichiometric. The intermediate low molecular weight polymer thus produced then undergoes reaction with additional alkali metal salt. By this method, a polyether polymer of closely controlled molecular weight can be conveniently prepared.

Abstract: Disclosed is a solvent soluble polyimide and a method for making thereof, which characterizes by producing a solvent soluble polyimide with low electric conductivity through the polymerization of an anhydride and a diamine under the condition with or without catalyst.

Abstract: Addition-cured polyimides that contain the reaction product of an aromatic triamine or trianhydride analogue thereof, a reactive end group such as 5-norbornene-2, 3-dicarboxylic acid, ester derivatives of 5-norbornene-2,3-dicarboxylic acid, anhydride derivatives of 5-norbornene-2,3-dicarboxylic acid, or 4-phenylethynylphthalic anhydride, an aromatic diamine, and a dialkyl ester of an aromatic tetracarboxylic acid. The resultant starlike polyimides exhibit lower melt flow viscosity than its linear counterparts, providing for improved processability of the polyimide. Also disclosed are methods for the synthesis of these polyimides as well as composite structures formed using these polyimides.

Abstract: A method for preparing polyamic acid and polyimide, which is suitable for use in adhesives or adhesive tapes for electronic parts. The polymers have such three-dimensional molecular structures that a significant improvement can be brought about in solvent solubility, thermal resistance, mechanical properties, and adhesive properties onto various substrates. The polyamic acid is prepared by reacting at least one tetracarboxylic dianhydride, at least one aromatic diamine, at least one diamine with a siloxane structure, represented by the following general formula I, and at least one polyamino compound represented by the following general formula II or III. The polyamic acid is converted into polyimide through thermal or chemical imidization.

Abstract: Bis(halophthalimides) such as, 3-bis[N-(4-chlorophthalimido)]benzene are prepared in slurry in an organic liquid such as o-dichlorobenzene or anisole, by a reaction at a temperature of at least 150° C. between at least one diamino compound, preferably an aromatic diamine such as m- or p-phenylenediamine, and at least one halophthalic anhydride such as 4-chlorophthalic anhydride, in the presence of an imidization catalyst such as sodium phenylphosphinate. The solids content of the reaction mixture is at least about 5% and preferably at least about 12% by weight. The product slurry may be employed directly in the preparation of polyetherimides, and similar slurries may be employed to prepare other polyether polymers.

Abstract: Polymerisable resins which comprise a porphyrinogenic ring system obtained by the reaction of: (a) one or more compounds selected from the group consisting of pyrrole and N-(lower)alkyl pyrroles, any of which may be optionally substituted, and (b) a C4-C6 saturated alicyclic ketone which is capable of reacting with the 2 or 5 position of the pyrrole ring. Resin coating systems comprising the said resins.

Abstract: Essentially colorless, transparent polyimide coatings and films prepared by combining aromatic dianhydrides with para-substituted aromatic diamines are provided. The polyimide coatings and films are produced by a process whereby the dianhydride and diamine monomer components are reacted at temperatures of greater than 80° C.

Abstract: A new poly (biphenyl ether sulfone) having improved polydispersity and also having low levels of low molecular weight oligomer.

Abstract: High quality films, preimpregnated tape (prepegs) and composites have been fabricated from polyimide precursor “salt-like” solutions. These “salt-like” solutions have a low viscosity (5,000 to 10,000 cp) and a high solids content (50-65% by weight) and can be coated onto reinforcing fiber to produce prepegs with excellent tack and drape at 12-15% residual solvent (˜4-6% water from thermal imidization reaction). The processing of these types of prepegs significantly overcomes solvent removal problems and allows excellent fiber wet out. In addition, the physical characteristics of the polyimide precursor “salt-like” solutions permits processing into high-performance materials through the use of standard prepregging and composite fabrication equipment. The resultant composites are of high quality.

Abstract: In order to produce a polymer electrolyte membrane from sulfonated, aromatic polyether ketone, an aromatic polyether ketone of the formula (I) in which Ar is a phenylene ring having p- and/or m-bonds, Ar′ is a phenylene, naphthylene, biphenylene, anthrylene or another divalent aromatic unit, X, N and M, independently of one another are 0 or 1, Y is 0, 1, 2 or 3, P is 1, 2, 3 or 4, is sulfonated and the sulfonic acid is isolated. At least 5% of the sulfonic groups in the sulfonic acid are converted into sulfonyl chloride groups, and these are reacted with an amine containing at least one crosslinkable substituent or a further functional group, and unreacted sulfonyl chloride groups are subsequently hydrolyzed. The resultant aromatic sulfonamide is isolated and dissolved in an organic solvent, the solution is converted into a film, and the crosslinkable substituents in the film are then crosslinked.

Abstract: A co-polymer of benzophenone and bisphenol A has been shown to have DUV absorption properties. Therefore, the co-polymer has particular utility as an antireflective coating in microlithography applications. Incorporating anthracene into the co-polymer backbone enhances absorption at 248 nm. The endcapper used for the co-polymer can vary widely depending on the needs of the user and can be selected to promote adhesion, stability, and absorption of different wavelengths.

Abstract: Disclosed is a composition which comprises (a) a polymer containing at least some monomer repeat units with photosensitivity-imparting substituents which enable crosslinking or chain extension of the polymer upon exposure to actinic radiation, said polymer being of the formula wherein x is an integer of 0 or 1, A is one of several specified groups, such as B is one of several specified groups, such as or mixtures thereof, and n is an integer representing the number of repeating monomer units, wherein said photosensitivity-imparting substituents are hydroxyalkyl groups; (b) at least one member selected from the group consisting of photoinitiators and sensitizers; and (c) an optional solvent. Also disclosed are processes for preparing the above polymers and methods of preparing thermal ink jet printheads containing the above polymers.

Abstract: The invention concerns a process for preparing linear or branched sulphurous polymers such as polyarylene sulphides, in particular polyphenylene sulphide, from an aromatic dihalide compound and a sulphide in a solvent, wherein a) the aromatic dihalide compound and the sulphide are partially reacted; b) the resultant salt which is not dissolved in the reaction medium is separated off; and c) the reaction mixture largely freed of the salt is further polymerized.

Abstract: The present invention relates to the synthesis of new type of diamine monomer, 1,3-bis(4-amonophenoxy)naphthalene, and with such a compound to produce a series of aromatic polymers, including polyamide, polyimide, copoly(amide-imide)s, etc., such polymers having excellent resistance to heat and mechanical properties.

Abstract: Disclosed is a process which comprises reacting a polymer of the general formula wherein x is an integer of 0 or 1, A is one of several specified groups, such as B is one of several specified groups, such as or mixtures thereof, and n is an integer representing the number of repeating monomer units, with a halomethyl alkyl ether, an acetyl halide, and methanol in the presence of a halogen-containing Lewis acid catalyst, thereby forming a halomethylated polymer.

Abstract: A process for producing polyimide microfine particles which is amenable to free control of particle morphology and particle diameter distribution is provided. A polyamic acid and a polyimide, each in the form of microfine particles with good monodispersibility, are also provided. There is also provided a process for producing polyimide microfine particles from a tetracarboxylic anhydride and a diamine compound which comprises (a) a first step of preparing a first solution containing the tetracarboxylic anhydride and a second solution containing the diamine compound, (b) a second step of mixing the first and second solutions and causing a polyamic acid to precipitate in the form of microfine particles from the mixed solution under ultrasonic agitation, and (c) a third step of imidating the polyamic acid particles to provide the objective polyimide in the form of microfine particles.

Abstract: Perfluoroether acylperoxides having an average equivalent weight in the range of 350-5000, and of the following formulae: Y′—(CF2—CF(CF3)O)m—(CX′FO)n—CF2CO—O—O—CO—CF2—(OCX′F)n—(OCF(CF3)—CF2)—Y′  (I) wherein Y′=Cl, ORf wherein Rf is a C1-C3 perfluoroalkyl; m, n are integers such that the average equivalent weight of (I) is in the range of 350-5000 and m/n≧40; X′=F, CF3; T—CF2—O—[(CF2CF2O)p—(CF2O)q—CF2—CO—O—O—CO—CF2(OCF2)q—(OCF2CF2)p]y—OCF2—COOH  (II) wherein y is an integer comprised between 1 and 5; p and q are integers such as to give the above mentioned EW and p/q=0.5 to 2.0; T=COOH, F with the proviso that when T=COOH y=1-5, when T=F then y=1, and processes for manufacturing them.

Abstract: The present invention is directed to polyimide systems which simultaneously offer low toxicity, a high glass transition temperature, excellent thermal oxidative stability, and desirable processing characteristics. These various polyimide systems include mixtures of monomeric reactants, polyimide-precursor reaction products, polyimides, and polyimide-containing articles. In one aspect of the invention, the mixture of monomeric reactants includes at least one dia-nhydride or a derivative thereof, and at least one diamine. The diamine may be 4,4′-[1,4-phenylene-bis(1-methylethylidene)]bisaniline, 4,4′-[1,3-phenylene-bis(1-methylethylidene)]bisaniline, and/or a derivative thereof. The diamine also may include a phenylenediamine, 2,2-bis[4-(4-aminophenoxyl)phenyl]propane, 4,4′(1,4-phenylene-bismethylene)bisaniline, and/or a derivative thereof. In addition, the mixture may include a reactive end-capping agent and/or a non-reactive end-capping agent.

Abstract: A polyimide precursor solid residuum is an admixture of an aromatic dianhydride or derivative thereof and an aromatic diamine or dervative thereof plus a complexing agent, which is complexed with the admixture by hydrogen bonding. The polyimide precursor solid residuum is effectively employed in the preparation of polyimide foam and the fabrication of polyimide foam structures.

Abstract: Polyimide copolymers were obtained containing 1,3-bis(3-aminophenoxy)benzene (APB) and other diamines and dianhydrides and terminating with the appropriate amount of a non-reactive endcapper, such as phthalic anhydride. Homopolymers containing only other diamines and dianhydrides which are not processable under conditions described previously can be made processable by incorporating various amounts of APB, depending on the chemical structures of the diamines and dianhydrides used. Polyimides that are more rigid in nature require more APB to impart processability than polyimides that are less rigid in nature. The copolymers that result from using APB to enhance processability have a unique combination of properties including: excellent thin film properties, low pressure processing (200 psi and below), improved toughness, improved solvent resistance, improved adhesive properties, improved composite mechanical properties, long term melt stability (several hours at 390 C.), and lower melt viscosities.

Abstract: A novel polyalkyl ether/polyaryl ether sulfone or ketone copolymer and a specific polyether ester copolymer are useful for producing a medical material to be used to contact the blood; and methods for producing the medical material comprising said polyalkyl ether/polyaryl ether sulfone or ketone copolymer or a specific polyether ester copolymer.

Abstract: The invention relates to a gas barrier composition as well as to composite structures having at least one surface of a molded resin coated with the composition, said composition comprising:(A) an alkoxysilyl functional polyamine compound, or a hydrolyzate thereof, said polyamine compound having three or more amine groups, at least one nitrogen atom of said amine groups being bonded to a hydrogen atom and at least one nitrogen of said amine groups being bonded to an alkoxysilyl group expressed by the formula--W--SiR.sup.2.sub.3-f (OR.sup.1).sub.fwherein R.sup.1 is an alkyl group having 1 to 6 carbon atoms, R.sup.

Abstract: The invention relates to a photosensitive polyimide resin composition comprising (A) a polyamic acid having, in its main chain, repeating units formed from a polycondensation product of at least one tetracarboxylic acid or tetracarboxylic anhydride thereof with at least one diamine compound, and having actinic ray-sensitive functional groups at both terminals thereof; (B) a photosensitive auxiliary having a photopolymerizable functional group; (C) a photopolymerization initiator; and (D) a solvent, wherein 1 the polyamic acid is such that when the repeating unit represented by the formula (1) is defined as a unit molecular weight, a unit molecular weight per carboxyl group (unit molecular weight/COOH) falls within a range of from 200 to 300, and 2 the photosensitive resin composition permits the formation of a polyimide film having a residual stress of 40 MPa or lower and a coefficient of thermal expansion of 30 ppm/.degree. C.

Abstract: A polymer composition made by combining a polyketone polymer and a phenolic alkylene dicarboxylate of the general formula: ##STR1## each R.sup.1 independently is hydrogen or alkyl with 1-6 carbon atoms, each R.sup.2 independently is alkyl with 1-6 carbon atoms,each m is an integer of 0-4, andn is an integer of 2-12; anda process for preparing these compositions.

Abstract: A compound of the formula: ##STR1## wherein Ar.sup.

Abstract: Polyimide copolymers were obtained containing 1,3-bis(3-aminophenoxy)benzene (APB) and other diamines and dianhydrides and terminating with the appropriate amount of reactive endcapper. The reactive endcappers studied include but should not be limited to 4-phenylethynyl phthalic anhydride (PEPA), 3-aminophenoxy-4'-phenylethynylbenzophenone (3-APEB), maleic anhydride (MA) and nadic anhydride (5-norbornene-2,3-dicarboxylic anhydride, NA). Homopolymers containing only other diamines and dianhydrides which are not processable under conditions described previously can be made processable by incorporating various amounts of APB, depending on the chemical structures of the diamines and dianhydrides used. By simply changing the ratio of APB to the other diamine in the polyimide backbone, a material with a unique combination of solubility, Tg, Tm, melt viscosity, toughness and elevated temperature mechanical properties can be prepared.

Abstract: A polyimide resin having good thermal stability and good adhesion to a metal foil is disclosed. The polyimide resin is prepared by dissolving at least one diamine in a polar aprotic solvent followed by the addition of an aromatic tetracarboxylic acid dianhydride to the solution of the aromatic diamines to prepare a polyamic acid solution, imidizing this solution to a polyimide resin by heating at a temperature above 250.degree. C., the polar aprotic solvent comprising at least 1 weight % of acetone. Polyimide laminates with a metal foil, such as a copper foil, are also described. The laminates may be used to form flexible printed circuit boards.

Abstract: A polyimide precursor solution having a high concentration yet low viscosity, a polyimide coating film having satisfactory physical properties which is prepared from the polyimide precursor solution, and a process for producing a polyimide coating film using the polyimide precursor solution. The polyimide precursor solution has dissolved therein a specific salt of a diamine and a tetracarboxylic acid and/or a dicarboxylic acid-dialkyl ester in a high concentration, the diamine and the tetracarboxylic acid and/or the dicarboxylic acid-dialkyl ester being capable of forming a polyimide. Also disclosed is a polyimide coating film obtained by heating the solution to cause imidization and a process for producing the polyimide coating film.

Abstract: Polyimide polymers from 3,4,3',4'-biphenyltetracarboxylic dianhydride and 3,4,3',4'-benzophenonetetracarboxylic dianhydride and a diamine such as p-phenylenediamine exhibit a high glass transition temperature, high thermal oxidative stability and low moisture regain, useful for structural applications.