Abstract: This invention relates to compositions, and the use of such compositions for protective coatings, particularly of electronic devices. The invention concerns fired-on-foil ceramic capacitors coated with a composite encapsulant and embedded in a printed wiring board.

Abstract: The present invention provides an amic acid ester oligomer with the structure of formula (1) wherein R, Rx, G, P and m are as defined in the specification. The present invention also provides a precursor composition for a polyimide resin comprising the above-mentioned oligomer of formula (1). The polyimide synthesized from the precursor composition exhibits good operations and physiochemical properties.

Abstract: An object of the present invention is to obtain a novel polymeric material capable of forming a solid polymer electrolyte excellent not only in processability, solvent resistance and durability/stability but also in ion conductivity by introducing sulfonic acid group or phosphonic acid group into a polybenzazole compound having excellent properties in view of heat resistance, solvent resistance, mechanical characteristics and the like. Means attaining the object of the present invention is a polybenzazole compound including an aromatic dicarboxylic acid bond unit having sulfonic acid group and/or phosphonic acid group and satisfying either a condition that inherent viscosity measured in concentrated sulfuric acid is in the range of 0.25 to 10 dl/g or a condition that inherent viscosity measured in a methanesulfonic acid solution is in the range of 0.1 to 50 dl/g.

Abstract: Disclosed are a polymer electrolyte having improved hot water resistance and radical resistance, a proton conductive membrane comprising the polymer electrolyte, and a membrane-electrode assembly including the proton conductive membrane. The polymer electrolyte comprises at least one polymer selected from polyether, polyketone, polyetherketone, polysulfone, polyethersulfone, polyimide, polyetherimide, polybenzimidazole, polybenzothiazole, polybenzoxazole and the like. The polymer comprises a repeating structural unit with either or both of an aromatic ring and a heterocyclic ring, and a repeating structural unit represented by the formula (1): wherein X is a single bond, an electron-withdrawing group or an electron-donating group; R is a single bond, —(CH2)q— or —(CF2)q— where q ranges from 1 to 10; m is from 0 to 10; k is from 0 to 5; l is from 0 to 4; and k+1?1.

Abstract: The present invention is generally directed to a hole transport polymer comprising a polymeric backbone having linked thereto a plurality of substituents comprising fused aromatic ring groups, with the proviso that the polymer does not contain groups selected from triarylamines and carbazole groups. It further relates to devices that are made with the polymer.

Abstract: A material for dielectric films is a polymerizable composition containing an organic solvent, and an adamantanepolycarboxylic acid derivative represented by following Formula (1): wherein X is hydrogen atom, a hydrocarbon group or R4; R1, R2, R3 and R4 and are each independently a protected or unprotected carboxyl group, etc.; and Y1, Y2, Y3 and Y4 are each independently a single bond or a bivalent aromatic cyclic group; and an aromatic polyamine derivative represented by following Formula (2): wherein Ring Z is a monocyclic or polycyclic aromatic ring; and R5, R6, R7 and R8 are each a substituent bound to Ring Z and are each independently a protected or unprotected amino group, etc., dissolved in the organic solvent.

Abstract: A diamine compound represented by the formula (1): wherein R1 is a trivalent organic group, each of X1 and X2 is a bivalent organic group, X3 is an alkyl or fluoroalkyl group having from 1 to 22 carbon atoms, or a cyclic substituent selected from aromatic rings, aliphatic rings, heterocyclic rings and their substituted groups, and n is an integer of from 2 to 5. And, a polyimide precursor and a polyimide synthesized by using the diamine compound; and a treating agent for liquid crystal alignment containing the polyimide precursor and/or the polyimide.

Abstract: A method for preparation of a sulfonic and or sulfonic acid salt containing polyimide resins comprising melt reaction of a polyimide resin with an organic compound, wherein the organic compound contains at least one aliphatic primary amine functionality and at least one other functionality selected from the group consisting of sulfonic acids, sulfonic acid salts or mixtures thereof.

Abstract: An aromatic amide block copolymer containing a specific aromatic amide compound unit and having a weight average molecular weight, as reduced into standard polystyrene measured by the gel permeation chromatography, of from 10,000 to 1,000,000.

Abstract: Polyimide resins that are suitable for processing by resin transfer molding (RTM) and resin infusion (RI) methods at reduced processing temperatures are provided. The inventive RTM and RI processable polyimide resins exhibit melting at temperatures of less than about 200° C. and melt viscosities at 200° C. of less than about 3000 centipoise. A process for synthesizing the inventive resins is also provided, as is a fiber-reinforced composite material. The fiber-reinforced composite material employs the inventive polyimide resin as its resin matrix and demonstrates good heat resistance and mechanical properties.

Abstract: Poly-o-hydroxyamides include binaphthyl substituents as repeating units. The poly-o-hydroxyamides can be cyclized to give the polybenzoxazole by heating. Pore formation occurs, so that a dielectric having a very low dielectric constant k of less than 2.5 is obtained.

Abstract: A material for dielectric films is a polymerizable composition containing an adamantanepolycarboxylic acid represented by following Formula (1): wherein X is a hydrogen atom, a carboxyl group or a hydrocarbon group; and Y1, Y2, Y3 and Y4 are the same as or different from one another and are each a single bond or a bivalent aromatic cyclic group; an aromatic polyamine represented by following Formula (2): wherein Ring Z is a monocyclic or polycyclic aromatic ring; and R1 and R2 are each a substituent bound to Ring Z, are the same as or different from each other and are each an amino group, a mono-substituted amino group, a hydroxyl group or a mercapto group; and a solvent other than ketones and aldehydes, in which the adamantanepolycarboxylic acid and aromatic polyamine are dissolved in the solvent

Abstract: In the process of the present invention, a solvent-soluble polyimide is produced by polycondensing at least one tetracarboxylic acid component with at least one diamine component in a solvent in the presence of a tertiary amine. The tetracarboxylic acid component is selected from the group consisting of tetracarboxylic dianhydrides represented by the following formula 1: wherein R is as defined in the specification, and tetracarboxylic acids and their derivatives represented by the following formula 2: wherein R and Y1 to Y4 are as defined in the specification. Unlike the conventional techniques using an excessively large amount of a chemical imidation agent such as acetic anhydride and a chemical imidation catalyst such as triethylamine, in the process of the present invention, the solvent-soluble polyimide having a high polymerization degree is easily produced in a solvent with good productivity by using only a catalytic amount of the tertiary amine.

Abstract: A preparation process of polyimide aerogels that composed of aromatic dianhydrides and aromatic diamines or a combined aromatic and aliphatic diamines is described. Also descried is a process to produce carbon aerogels derived from polyimide aerogel composed of a rigid aromatic diamine and an aromatic dianhydride. Finally, the processes to produce carbon aerogels or xerogel-aerogel hybrid, both of which impregnated with highly dispersed transition metal clusters, and metal carbide aerogels, deriving from the polyimide aerogels composed of a rigid aromatic diamine and an aromatic dianhydride, are described. The polyimide aerogels and the polyimide aerogel derivatives consist of interconnecting mesopores with average pore size at 10 to 30 nm and a mono-dispersed pore size distribution. The gel density could be as low as 0.008 g/cc and accessible surface area as high as 1300 m2/g.

Abstract: Disclosed herein are polyetherimide compositions comprising structural units of the formula: derived from at least one benzimidazole diamine, wherein R1 and R2 are independently selected from hydrogen and C1–C6 alkyl groups; “A” comprises structural units of the formulae: or mixtures of the foregoing structural units; wherein “D” is a divalent aromatic group, R3 and R10–R12 are independently selected from hydrogen, halogen, and C1–C6 alkyl groups; “q” is an integer having a value of 1 up to the number of positions available on the aromatic ring for substitution; and “W” is a linking group; and “B” comprises substituted and unsubstituted arylene groups having from about 6 to about 25 carbon atoms. Methods for producing the polyetherimide compositions are also disclosed herein.

Abstract: The invention relates to novel polyhydroxyamide compounds that, in the form of their oxazoles, ane suited as a coating material, particularly for electronic components. The invention also relates to a method for producing these novel compounds and to the use thereof.

Abstract: A method for preparing a polyimide includes introducing a mixture of an oligomer and a solvent to an extruder, removing solvent via at least one extruder vent, and melt kneading the oligomer to form a polyimide. The polyimide has a low residual solvent content. The method is faster than solution polymerization of polyimides, and it avoids the stoichiometric inaccuracies associated with reactive extrusion processes that use monomers as starting materials.

Abstract: A novel polyimide resin consisting essentially of 3,3?,4,4?-benzophenonetetracarboxylic dianhydride (BTDA), 3,4,3?,4?-biphenyltetracarboxylic dianhydride (BPDA), 2,2 bis (3?,4?-dicarboxy phenyl) hexafluoro propane dianhydride (6FDA), 2-(3,4-dicarboxyphenyl)-1-phenylacetylene anhydride (4-PEPA) and an aromatic diamine.

Abstract: Polyimide sulfone resins are provided with a glass transition temperature of from 200–350° C., residual volatile species concentration of less than 500 ppm and a total reactive end group concentration of less than about 120 milliequivalents/kilogram resin. The resins have high heat capability and good melt stability. Methods to prepare the said resins and articles made from the resins are also provided.

Abstract: The present invention relates to a polyimide adhesive composition having a polyimide derived from an aromatic dianhydride and a diamine component, where the diamine component is preferably about 50 to 90 mole % of an aliphatic diamine and about 10 to 50 mole % of an aromatic diamine. In one embodiment, the aliphatic diamine has the structural formula H2N—R—NH2 wherein R is hydrocarbon from C4 to C16 and the polyimide adhesive has a glass transition temperature in the range of from 150° C. to 200° C. The present invention also relates to compositions comprising the polyimide adhesive of the present invention, including polyimide metal-clad laminate useful as flexible circuit when metal traces are formed out of the metal used in flexible, rigid, or flex-rigid circuit applications.

Abstract: A producing process of amino resin crosslinked particles includes the step of curing an emulsion of an amino resin precursor and an emulsifier in the presence of a catalyst, the amino resin precursor being a product of a reaction of an amino compound with formaldehyde, so as to prepare amino resin particles, the step of neutralizing the suspension of the amino resin particles after the curing step, and the step of heating the suspension in a temperature range of 130° C. to 230° C. after the neutralizing step. The amino resin crosslinked particles thus prepared by the condensation of the amino compound and formaldehyde generate formaldehyde in an amount of not more than 1000 ppm in a pyrolysis test and have a characteristic that a Hunter whiteness is not less than 85 percent.

Abstract: The present invention relates to novel polyimides derived from 6FDA and from 3,3-dihydroxy-4,4?-diaminobiphenyl and novel polyimides derived from PMDA and from Bis-AP-AF, having alkyl, arylalkyl, heteroarylalkyl, (cycloalkyl)alkyl, fluoroalkyl or siloxane side groups. The present invention also relates to a method of producing nematic liquid-crystal devices, which comprises the steps consisting in: depositing one of the polyimides according to the invention on a substrate; annealing the polyimide in one or more steps; and defining an azimuthal orientation of the polyimide coating.

Abstract: A new class of hybrid organic-inorganic materials, and methods of synthesis, that can be used as a proton exchange membrane in a direct methanol fuel cell. In contrast with Nafion® PEM materials, which have random sulfonation, the new class of materials have ordered sulfonation achieved through self-assembly of alternating polyimide segments of different molecular weights comprising, for example, highly sulfonated hydrophilic PDA-DASA polyimide segment alternating with an unsulfonated hydrophobic 6FDA-DAS polyimide segment. An inorganic phase, e.g., 0.5–5 wt % TEOS, can be incorporated in the sulfonated polyimide copolymer to further improve its properties. The new materials exhibit reduced swelling when exposed to water, increased thermal stability, and decreased O2 and H2 gas permeability, while retaining proton conductivities similar to Nafion®. These improved properties may allow direct methanol fuel cells to operate at higher temperatures and with higher efficiencies due to reduced methanol crossover.

Abstract: A terminal-crosslinkable polyamic acid oligomer having 1) heat resistance indicated by Tg of 300° C. or more and a pyrolysis temperature of 500° C. or more, 2) toughness, and 3) capability of allowing an increase in concentration. The polyamic acid oligomer is obtained by reacting an aromatic tetracarboxylic dianhydride including 2,2?,3,3?-biphenyltetracarboxylic dianhydride, an aromatic diamine compound, and a reactive crosslinking agent including an amino group or acid anhydride group and a crosslinkable group in the molecule, and includes a crosslinkable group at the molecular terminal.

Abstract: The present invention provides a flexible printed circuit which is free from curl, torsion and warpage due to temperature change and excellent flexural endurance. By using polyimide film having an average coefficient of thermal expansion of 1.0×10?5 to 2.5×10?5 cm/cm/° C. in a temperature range of 100° C. to 200° C. and a stiffness value of 0.4 to 1.2 g/cm as the base film for the flexible printed circuit, a flexible printed circuit having excellent thermal dimensional stability and flexural endurance can be prepared.

Abstract: The invention relates to biocidal polymers based on guanidine salts characterized in that they are representatives of a number of polyoxyalkylene guanidines and their salts and are a product of a polycondensation of guanidine salts with diamines which include two amino groups and polyoxyalkylene chains therebetween. In addition to a high bactericidity, these new polymer products are provided with a relatively low toxicity, an increased hydrophily, a quick and complete dilution in water, increased values of relative molar mass, and distinct characteristics of polymer surface active substances.

Abstract: The present invention relates to a method of preparing a solution of a polymer comprising recurring azole units, which comprises dissolving a sufficiently dried polymer comprising recurring azole units of the formula where the radicals Ar, Ar1 and Ar2 are tetravalent, divalent or trivalent aromatic or heteroaromatic groups and the radicals X, which are identical within a repeating unit, are each an oxygen atom, a sulfur atom or an amino group bearing a hydrogen atom, a group having 1–20 carbon atoms, preferably a branched or unbranched alkyl or alkoxy group, or an aryl group as further radical, in N,N-dimethylacetamide having a sufficiently low water content at a temperature above room temperature under an inert gas atmosphere, wherein a sufficiently dried polymer comprising recurring azole units of the formula (1) or (2) of which 90% by weight based on the total weight of the polymer comprising recurring azole units has a particle size of less than 1 mm is used.

Abstract: This invention relates to a siloxane-modified polyimide resin which shows excellent adhesiveness and can be bonded by thermocompression at high temperature even after subjection to thermal hysteresis in the manufacturing step for electronic parts. This polyimide resin is obtained from an aromatic tetracarboxylic acid dianhydride (A) and a diamine (B) comprising 30–95 mol % of a bis(4-aminophenoxy)alkane (B1) and 5–70 mol % of a siloxanediamine (B2) as essential components.

Abstract: This invention relates to polyimides having improved thermal-oxidative stability, to the process of preparing said polyimides, and the use of polyimide prepolymers in the preparation of prepregs and composites. The polyimides are particularly useful in the preparation of fiber-reinforced, high-temperature composites for use in various engine parts including inlets, fan ducts, exit flaps and other parts of high speed aircraft.

Abstract: The substrates of the present invention comprise a polyimide base polymer derived at least in part from collinear monomers together with crankshaft monomers. The resulting polyimide material has been found to provide advantageous properties, particularly for electronics type applications.

Abstract: Provided are polyimide and a thin film thereof which have a three-dimensional structure and therefore are excellent in a mechanical strength and a heat resistance as compared with those of conventional linear polyimide. The polyimide is obtained from a salt of multifunctional amine represented by Formula (1): (wherein A represents a tetravalent organic group, and n represents an integer of 0 to 3) and tetracarboxylic diester represented by Formula (2): (wherein B represents a tetravalent organic group having 1 to 20 carbon atoms, and R1 and R2 each represent independently an alkyl group having 1 to 5 carbon atoms).

Abstract: A polyimide resin having phenolic hydroxyl radicals in its skeleton is prepared using a diamine bearing an aromatic ring having an amino radical attached thereto and another aromatic ring having a phenolic hydroxyl radical. The polyimide resin and a composition comprising the polyimide resin, an epoxy resin and a curing agent are suited for use as varnish, adhesive and adhesive film for which adhesion and heat resistance are required.

Abstract: Polyimide precursors contained in resin compositions of the present invention have a polymer structure unit represented by formula (1) below: wherein chemical structure A2 includes an alicyclic compound but not an aromatic compound such as a benzene ring so that they provide excellent light transmission over a wide wavelength range. The polyimide precursors are imidized at 7.5% or more and 36% or less so that they are less soluble in developing solutions and therefore are not dissolved in the developing solutions at unexposed parts. Thus, the resin compositions of the present invention can be used to form a resin film having a precise pattern by exposure and development.

Abstract: A polyimide excelling in heat resistance, chemical resistance, water repellency, dielectric characteristics, electrical characteristics, and optical characteristics and a polyamide acid useful as the raw material therefor are provided. Specifically, a polyamide acid containing a chlorine atom and a fluorine atom and comprising a repeating unit represented by the following formula (1): (wherein X and X? independently denote a divalent organic group; Y and Y? independently denote a chlorine, bromine, or iodine atom; p and p? denote independently denote the number of fluorine atom {F in the formula (1)} bonded to the relevant benzene ring, representing an integer of 0-3; q and q? independently denote an integer of 0-3; and p+q total 3, and p?+q? total 3).

Abstract: Methods of reducing the amount of undesirable cyclic oligomer by-products in the production of polyetherimides are disclosed. The resulting polyetherimides have enhanced thermomechanical properties.

Abstract: A polyimide composition and a process to prepare polyimide resins with reduced plate out and mold deposits is described. During resin molding operations the low plate out resins show a longer period of operation between cleaning of equipment leading to more efficient operation.

Abstract: A process of preparing a polyimide of the present invention comprises effecting an imidization reaction of a diamine and a tetracarboxylic dianhydride in a solvent containing 50 to 100% by weight of an equimolar composition of a nitrogen-containing cyclic compound indicated by chemical formula (1) below and a phenol indicated by chemical formula (2) below: in formula (1), X represents —CH2— or —N(CH3)—, and in formula (2), R1 and R2 may be the same as, or different from, each other and represent each any one of —H, —OH, —CH3, —C2H5, —C3H7, —C4H9, —C5H11, —C6H13, —C7H15, —C8H17, —C9H19, —C10H21, —OCH3, —O(C6H5), —NO2, —Cl, —Br and —F.

Abstract: The present invention also includes an imageable element, comprising a substrate and a thermally imageable composition comprising a thermally sensitive polymer which exhibits an increased solubility in an aqueous developer solution upon heating. The thermally sensitive polymer includes at least one covalently bonded unit and at least one thermally reversible non-covalently bonded unit, which includes a two or more centered H-bond within each of the non-covalently bonded unit. The present invention also includes a method of producing the imaged element. The present invention still further includes a thermally imageable composition comprising comprising a thermally sensitive polymer according to the present invention and a process for preparing the thermally sensitive polymer, which is a supramolecular polymer.

Abstract: A series of low melting and low viscosity phenylethynyl end-capped polyimides (PETIs) possessed of long term thermal and mechanical stability useful as films, melt coatings, adhesives, matrix and RTM resins and particular as coatings for optical fibers and phenylethynyl end-capped bismides blended with PETIs are disclosed. Processes for their production including: 1) modification of PETI-5 oligomer by molecular weight adjustments by blending with reactive low melting phenylethynyl end-capped imide monomers, 2) modification of the PETI-5 backbone structure with other diamine components, and 3) modification of the PETI-5 backbone with bulky fluorinated groups are also disclosed.

Abstract: The invention provides a polyimide film manufactured from a polyamic acid prepared from pyromellitic dianhydride in combination with 10 to 60 mol % of phenylenediamine and 40 to 90 mol % of 3,4?-oxydianiline, based on the overall diamine. The polyimide film, when used as a metal interconnect board substrate in flexible circuits, chip scale packages (CSP), ball grid arrays (BGA) or tape-automated bonding (TAB) tape by providing metal interconnects on the surface thereof, achieves a good balance between a high elastic modulus, a low thermal expansion coefficient, alkali etchability and film formability.

Abstract: Poly-o-hydroxyamides are cyclicized to obtain polybenzoxazoles. The poly-o-hydroxyamides provide effective filling of trenches. In particular, the poly-o-hydroxyamides can fill trenches having a width of less than 100 nm and an aspect ratio of more than 4. Further, the polybenzoxazoles of the invention are very suitable for the damascene process. A dielectric can be made from the polybenzoxazole. In turn, semiconductor devices can include the dieletric. Processes for making the poly-o-hydroxyamides, polybenzoxazoles, and semiconductor devices are included.

Abstract: A polyimide-based polycondensate which may be used as an insulation film by coating a copper foil with the polycondensate and by heating the coated copper foil, which insulation film does not warp the foil, as well as a production process thereof, is disclosed. The polycondensate according to the invention is a solvent-soluble polycondensate containing a benzoxazole component having a carboxylic group and an imide component having a phenolic hydroxyl group, which is obtained by dehydration-condensing one or more tetracarboxylic dianhydrides with one or more aromatic diamines having an amino group and a phenolic hydroxyl group, the amino group and the phenolic hydroxyl group being located at ortho positions with respect to each other, by heating the one or more tetracarboxylic dianhydrides and the one or more aromatic diamines at 150° C. to 220° C. in the presence of an acid catalyst.

Abstract: The present invention provides an optical polyimide precursor for use in making a polyimide. The precursor is defined by the following formula: wherein X is Cl, Br, oxo-halide, or fully halogenated alkyl, and A is a divalent aromatic or halogenated aromatic moiety. The present invention provides a method of preparing a diamine compound for use as an optical polyimide precursor. The method includes the steps of dissolving 2-chloro-5-nitrobenzotrifluoride and a diol in N,N-dimethylacetamide to form a solution, adding potassium carbonate, tert-butylammonium chloride and copper powder to said solution and heating the resulting mixture, removing the copper, precipitating and recrystallizing a dinitro-compound resulting from heating the mixture, and dissolving the dinitro-compound and reducing the dinitro-compound to yield a diamine compound.

Abstract: An adhesive polyimide resin which comprises a siloxane polyimide resin obtained from (A) an aromatic tetracarboxylic dianhydride and (B) a diamine ingredient comprising (B1) a diamine having a phenolic hydroxyl group, carboxyl group, or vinyl group as a crosslinkable reactive group and (B2) a siloxanediamine and has a glass transition temperature of 50 to 250?C and a Young's modulus (storage modulus) at 250?C of 105 Pa or higher; and a laminate which comprises a substrate comprising a conductor layer and an insulating supporting layer having at least one polyimide resin layer and, disposed on a surface of the substrate, an adhesive layer comprising a layer of the adhesive polyimide resin. The adhesive polyimide resin and the laminate have satisfactory adhesion strength even after exposure to a high temperature of up to 270?C and further have excellent heat resistance in reflow ovens. They are hence suitable for use in the bonding of electronic parts.

Abstract: A thermosetting polyimide resin composition is provided which comprises a polyimide resin and an epoxy resin, which has excellent heat resistance, low dielectric constant and low dielectric loss tangent and also yields a cured article having good mechanical properties such as tensile strength and tensile elongation. Also, a process for producing a polyimide resin used in the polyimide resin composition is provided. The thermosetting polyimide resin composition comprises a polyimide resin (X), which has a carboxyl group and a linear hydrocarbon structure having a number-average molecular weight of 300 to 6,000, and an epoxy resin (Y).

Abstract: A method for the synthesis of poly(etherimide)s comprises the reaction of 4-halotetrahydrophthalic anhydride with an activating primary amine to yield an activated 4-halotetrahydrophthalimide. Activated 4-halotetrahydrophthalimide may then be aromatized and treated with the disodium salt of a bis(phenol) to yield an activated bisimide. The activated bisimide may then be directly treated with a diamine to yield poly(etherimide)s.

Abstract: Polyetherpolyamide elastomer showing a low water absorption, a high stress relaxation, and a high elastic recovery percentage of elongation is obtainable by polymerizing an aminocarboxylic acid compound and/or a lactam compound, a triblock polyetherdiamine compound having the following formula, and a dicarboxylic acid compound: [x is a value of 1 to 20, y is a value of 4 to 50, z is a value of 1 to 20].

Abstract: A polyimide is disclosed of the formula: CG1 and CG2 are independently electron-accepting and/or electron-donating groups; x is an integer from about 3 to about 3000; ODAH is any of a number of known dianhydride residues; ODAM is any of a number of known diamine residues; and m, n, o, and p cumulatively add to 1.0, with the sum of m and n ranging from about 0.05 to about 1.0, the sum of o and p ranging from about 0 to about 0.95, the sum of m and o being about 0.5 and the sum of n and p being about 0.5. In addition, a film structure comprising the polyimide and devices utilizing the film structure are disclosed.

Abstract: In a step of polymerizing polyamic acid by mixing tetracarboxylic acid dianhydride and diamine and polycondensating the tetracarboxylic acid dianhydride and diamine under the presence of a polymerization-use solvent, a tetracarboxylic acid dianhydride slurry in which a tetracarboxylic acid dianhydride is dispersed in a dispersion medium is used. According to this, it is possible to directly manufacture a polyamic acid solution having a high concentration of polyamic acid more than or equal to 10% by weight. Especially, even if a tetracarboxylic acid dianhydride having low solubility in the polymerization-use solvent, it is possible to effectively manufacture a polyamic acid solution having high solids content, by a simple process and in a short time.

Abstract: A poly amic acid precursor containing a combination of tetrahydrofuran and N-methylpyrrolidinone as cosolvents is described. Utilizing the combination of tetrahydrofuran and N-methylpyrrolidinone allows for the removal of significant portions of the solvent during the formation of the polyimide. The removal of tetrahydrofuran and N-methylpyrrolidinone can be done without the use of preheating zones so as to allow for the large scale production of polyimide articles.