Abstract: A polyimide-containing liquid crystal alignment treating agent having a structure of the formula (I) incorporated therein, wherein Q is a single bond or a divalent organic group, R1 to R4 represent aromatic groups, and R1 to R4 may be the same as, or different from, one another.

Abstract: The invention relates to a polymer material having electro optic and nonlinear optical properties suitable for manufacturing a device using the electro optic and nonlinear optical properties. More particularly, the present invention relates to a polymer material having excellent electro optic properties and optical nonlinearities, maintaining the properties under the manufacturing conditions of high temperature, and having physical, chemical, and optical stabilities by introducing an organic chromophore as a side chain of the polymer so that the polymer material can be suitable for manufacturing an electro optic and nonlinear optical device, to a film manufactured from the polymer material, and to a method of manufacturing the polymer material.

Abstract: A vertical alignment polyimide for LCD has the following structure: wherein R1 and R2 are same or different tetravalent aromatic residues or alkyl residues; n is an integer, and 24?n?6; a:b=1:9 to 9:1, preferably from 4:1 to 1:1; and a+b=p+q. The polyimide has an inherent viscosity of 0.04–5 dl/g.

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: The present invention relates to a polyamideimide resin solution preparable by reacting (a) aromatic polycarboxylic acids and/or their anhydrides with (b) aromatic imide- and amide-forming components in cresol at temperatures above 170° C., to the use of this polyamideimide solution for the preparation of wire enamels, to the wire enamels in question, and to the enamelled wires coated therewith.

Abstract: A polyimide film according to the present invention satisfies Condition (1) in which a tear propagation resistance variation CH is not more than 1.0 g, and/or Condition (2) in which a swelling coefficient CR after being dipped in an alkaline solution is not more than 20.0. By satisfying these conditions, workability of the polyimide film can be improved and working defects can be effectively prevented, thereby improving productivity of each step.

Abstract: Polyimides displaying low color in thin films, atomic oxygen resistance, vacuum ultraviolet radiation resistance, solubility in organic solvents in the imide form, high glass transition (Tg) temperatures, and high thermal stability are provided. The poly(amide acid)s, copoly(amide acid)s, polyimides and copolyimides are prepared by the reaction of stoichiometric ratios of an aromatic dianhydride with diamines which contain phenylphosphine oxide groups in polar aprotic solvents. Controlled molecular weight oligomeric (amide acid)s and imides can be prepared by offsetting the stoichiometry according to the Carothers equation using excess diamine and endcapping with aromatic anhydrides.

Abstract: A liquid crystal alignment treating agent for optical alignment treatment, whereby it is possible to obtain a liquid crystal alignment film which presents a high and stable tilt angle of liquid crystal and which is excellent in an accumulated charge property by a DC voltage, is provided.

Abstract: A liquid crystal alignment treating agent containing a polyamic acid which is represented by the following formula (I) and exhibits a reduced viscosity of from 0.05 to 5.0 dl/g (in N-methyl-2-pyrrolidone at 30° C. at a concentration of 0.5 g/dl) or a polyimide obtained by cyclodehydration thereof: wherein R1 represents a tetravalent organic group, at least 20 mol % of which has a fused alicyclic structure composed of two to five rings, and all of the carbonyl groups are directly bonded to the alicyclic structure and that any two carbonyl groups are not bonded to adjacent carbon atoms of the alicyclic structure; R2 is a bivalent organic group, from 20 to 100 mol % of which has in the side-chain structure at least one structural unit selected from the group consisting of C5-20 long-chain alkyl, C5-20 fluoroalkyl, alicyclic structures and aromatic ring structures; and L is a positive integer.

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: 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: An aromatic polyamide photoalignment material prepared by a reaction from a diamine compound with a side branch and a photosensitive dicarboxylic acid. Furthermore, liquid crystal display devices using such photoalignment materials in an alignment film on at least one substrate.

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: The present invention provides a polyimide resin for an electrical insulating material which comprises a polyimide resin having a repeating unit represented by general formula (I): wherein R1 represents a bivalent organic group.

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: This invention relates to a laminate which is excellent in heat resistance after moisture absorption required in a lead-free solder joint, and is suitable for use in flexible printed wiring boards or HDD suspensions. The laminate for electronic materials of this invention is constituted of a conductor layer and an insulating resin layer having a polyimide-based resin layer (A) and a polyimide-based resin layer (B). The polyimide-based resin layer (A) constituting the insulating layer includes a polyimide-based resin obtained by reacting a diamine containing 40 mol % or more of 4,4?-diamino-2,2?-dimethylbiphenyl with an aromatic tetracarboxylic acid, and the polyimide-based resin layer (B) includes a polyimide-based resin containing 80 mol % or more of a structural unit generated from bis(4-aminophenoxy)benzene or 2,2-bis[4-(4-aminophenoxy)phenyl]propane, and pyromellitic acid, benzophenonetetracarboxylic acid, diphenylsulfonetetracarboxylic acid or biphenyltetracarboxylic acid.

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: A polyimide precursor resin solution composition sheet having a solvent content of 1–50% by weight and a thickness of 1–10 microns has improved adhesion, forms a heat resistant polyimide layer when cured, and is advantageously used in the bonding of conductors to plastic films.

Abstract: A process for the production of high molecular weight polybenzimidazole by one: providing a first reaction vessel; charging the reaction vessel with at least one aromatic hydrocarbon tetraamine, and a heterocylic ring making up the dicarboxylic component; heating the reactants under agitation in a substantially oxygen-free atmosphere with agitation until the agitator torque is about 1.5 times the torque before a rise in viscosity begins; terminating the agitation while continuing to heat the reaction mixture to about 230° C. while allowing the reaction mass to foam; cooling the reaction mass to a friable foamed mass; crushing the friable foamed mass to obtain a ground prepolymer; and two: providing a second reaction vessel, the second reaction vessel being a high intensity reaction vessel; transferring the ground prepolymer to the second reaction vessel; heating the ground prepolymer under agitation to over 315° C. at atmospheric pressure for a time of about 90 minutes.

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: A process for a single-stage melt polymerization for the production of a high molecular weight polybenzimidazole which comprises the steps of: providing a reaction vessel having a means for agitation and a means for vacuum; charging the reaction vessel with reactants selected from: (A) a tetraaminiobiphenyl (TAB), and (B) a diphenyl isophthalate (DPIP); reacting the reactants under constant agitation and under a vacuum with an inert gas sweep; maintaining a reactant temperature which does not exceed 290° C. under constant agitation allowing pressure in the vessel to increase, with an inert gas sweep until a phase change is achieved, when the temperature reaches 250° C. pressure is increased to a slight positive pressure; and increase the reactant temperature and pressure within said reaction vessel while maintaining constant agitation and inert gas sweep, while maintaining a slight positive pressure. Preferably the vessel used in the instant invention is a high intensity reaction vessel.

Abstract: A photoactive side-chain polymer from the class of polyimides, polyamide acids and esters thereof, comprising as a side-chain a dendritic block incorporating photoactive groups at its surface. The dendritic block preferably represents a unit of formulae Ia, Ib or a combination of them, for example formulae Ic, wherein the broken line symbolizes the linkage to the polyimide main chain. The polymer may be used as an orientation layer for liquid crystals and in the construction of unstructured and structured optical elements and multi-layer systems.

Abstract: A polycarbodiimide copolymer which comprises at least one structural unit selected from rubber residues represented by the following formulae (1) and (2) in a number “m”: and a structural unit represented by the following formula (3) in a number “n”: and which comprises on both termini a terminal structural unit derived from a monoisocyanate, wherein m is an integer of 2 or more, n is an integer of 1 or more, m+n is from 3 to 1,500 and m/(m+n) is from 1/1,500 to ?. The polycarbodiimide is capable of keeping the inherent heat resistance and also showing excellent flexibility. Films and molding materials having high heat resistance and flexibility can be obtained.

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: 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: This invention relates to the composition and a solvent-free process for preparing novel imide oligomers and polymers specifically formulated with effective amounts of a dianhydride such as 2,3,3?,4-biphenyltetra carboxylic dianydride (a-BPDA), at least one aromatic diamine and an endcapped of 4-phenylethynylphthalic anhydride (PEPA) or nadic anhydride to produce imide oligomers that possess a low-melt viscosity of 1–60 poise at 260–280° C. When the imide oligomer melt is cured at about 371° C. in a press or autoclave under 100–500 psi, the melt resulted in a thermoset polyimide having a glass transition temperature (Tg) equal to and above 310° C. A novel feature of this process is that the monomers; namely the dianhydrides, diamines and the endcaps, are melt processable to form imide oligomers at temperatures ranging between 232–280° C. (450–535° F.) without any solvent.

Abstract: The present invention provides novel polyamic acids and polyimide optical alignment layers for inducing alignment of a liquid crystal medium. The novel compositions comprise reactive diamines containing a C3–C20 linear or branched hydrocarbon chains containing 1 to 4 carbon—carbon double bonds. The invention further describes liquid crystal displays comprising the novel polyimide optical alignment layers.

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 provides novel polyamic acids and polyimide optical alignment layers for inducing alignment of a liquid crystal medium. The novel compositions comprise crosslinking diamines containing a C3–C22 linear or branched hydrocarbon chains containing 1 to 4 carbon—carbon double bonds. The invention further describes liquid crystal displays comprising the novel polyimide optical alignment layers.

Abstract: The present invention relates to a method of producing high-density polyidimide (HPI) films and its production equipment. The production equipment comprises a raw material supplying means, a vacuum cavity, an energy supplier, a clad laminator, and a baked solidified polymer. The foregoing components constitutes the production equipment, using the monomer with the CONH bond or copolymer as raw materials to extract the unsaturated C?N bond by heat, electrons, light, radiation rays or ions as energy under low-pressure environment, so that the H in vacuum can extract the non-solidified HPI film from the electronic radical covalent polymers and via heat or light to rearrange the structure into a solidified HPI film. By means of the method according to the present invention, the original HPI that is not easily to produce as a film can be easily made in form of a film of HPI polymer on the clad laminator.

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 present invention relates generally to polyimides. It relates particularly to novel polyimides prepared from 2,3,3?,4?-biphenyltetracarboxylic dianhydride and aromatic diamines. These novel polyimides have low color, good solubility, high thermal emissivity, low solar absorptivity and high tensile strength.

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: The substrates of the present invention comprise a polyimide base polymer derived at least in part from non-rigid rod monomers together with optionally rigid rod monomers where the substrates are cured under low tension. The resulting polyimide materials have been found to provide advantageous properties (e.g. balanced molecular orientation, good dimensional stability, and flatness) particularly useful 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: 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: A polyhydroxyalkanoate that comprises a unit represented by the following chemical formula (1): wherein R1 is a substituent of an aromatic ring selected from the group consisting of H, CH3, C2H5, CH3CH2CH2, (CH3)2CH, (CH3)3C, a halogen atom, CN, NO2, COOR?, and SO2R?, wherein R? is selected from the group consisting of H, Na, K, CH3, and C2H5, and R? is selected from the group consisting of OH, a halogen atom, ONa, OK, OCH3, and OC2H5; and x represents an integer of 1 to 8 being the same or different each other in the polyhydroxyalkanoate. A method for producing the polyhydroxyalkanoate is also provided.

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.