Abstract: The present invention provides a flexible metal-clad laminate obtained by directly applying a polyimide precursor to a metallic conductive foil, and then drying, heating and curing the precursor to form a polyimide film, this flexible metal-clad laminate being characterized in that the polyimide film is composed of two or more polyimide layers, the linear thermal expansion coefficient of at least one of the second and later polyimide layers is larger than that of the first layer brought into contact with the metallic conductive foil, and the requirements of the following formulae are met:3.0<Q.sub.n-1 .times.t.sub.n <50,t.sub.n-1 >t.sub.n and ##EQU1## wherein t.sub.n is the thickness (.mu.m) of the outermost layer (the nth layer) of the polyimide layers, t.sub.n-1 is the thickness (.mu.m) of the film comprising the first layer to the (n-1)th layer of the polyimide layers, and Q.sub.

Abstract: A method for producing circuit boards with a film having improved printing properties, adhesion, flexibility and heat resistance which comprises applying a liquid printing ink composition comprising an admixture of a solvent, a polyamide-acid and a partially imidized polyamide-acid, then heat to effect drying and curing.

Abstract: A flexible copper-applied substrate comprises a copper foil and a resin layer comprising a composite material of a polyimide and a polyimide silicone, the resin layer being directly formed on the surface of the copper foil, said substrate being producible by applying a polyamide acid composite composed of a mixed solution of a polyamide acid and a polyamide acid alkylsilane to a copper foil and heating.

Abstract: A flexible double-sided copper-clad printed-circuit base board is provided with a core resin layer of a composite material essentially composed of a specific rigid-structured polyimide and a specific flexible-structured crosslinked polyimide silicone in a state of being inseparable from each other, wherein the core resin layer is formed directly between two copper foils. This base board is produced by coating a surface of a copper foil with a polyamic acid solution mixture of a specific polyamic acid and a specific polyamic acid - alkylsilane, heat-treating the resulting coated copper foil, and contact-bonding another copper foil to the resulting copper-foil/polyimide laminate.

Abstract: In a process for producing a flexible printed base by directly coating a copper foil with a polyimide precursor, followed by heating, drying and curing, a process affording a flexible printed base having a superior folding endurance and a good heat resistance at a cheap cost is provided, which process comprises carrying out the curing in an inert gas under a tension of 0.02 to 0.2 Kg/cm and at 200.degree. and 450.degree. C.

Abstract: A polyimide having a low elastic modulus and also superior heat resistance and mechanical characteristics and soluble in solvents and a process for producing the same are provided,which polyimide comprises as main components, 60 to 99% by mol of repetition units of the formula (I) and 1 to 40% by mol of repetition units of the formula (II) ##STR1## wherein Ar is a tetravalent aromatic group; X and Y are at least one group bonded to phenyl group at o-position relative to N atom and selected from 1-4C alkyl, CO group or OH group; R.sup.1 is a 3-5C divalent alkyl or phenylene; R.sup.2 is 4 or less C alkyl or phenyl; l and m are each 1 to 4; and n is 20 to 300, andwhich polyimide is produced by reacting diamino compounds consisting of 60 to 99% by mol of an aromatic diamine of the formula (V) and 1 to 40% by mol of a silicone diamine of the formula (VI), with an aromatic tetracarboxylic acid dianhydride of the formula (IV) in an organic polar solvent at 20.degree.-250.degree. C., ##STR2## wherein Ar, X, Y, R.sup.

Abstract: A process for producing a silicon-containing polyamic acid affording a silicon-containing polyimide having a low thermal expansion coefficient and a process for producing the silicon-containing polyimide are provided, the former process comprising reacting pyromellitic acid dianhydride (A.sup.1 mols) and 3,3',4,4'-biphenyltetracarboxylic acid dianhydride (A.sup.2 mols) with a diamine of the following formula (I) (B mols) and an aminosilicon compound of the formula (II) so as to satisfy the following expressions (III) and (IV): ##STR1## wherein R.sup.1 is methyl, ethyl, methoxy, ethoxy or halogen; R.sup.2 is alkyl or alkyl-substituted phenyl; X is a hydrolyzable alkoxy, acetoxy or halogen; m is 0, 1 or 2; n is 1 or 2; and k is 1, 2 or 3; andthe latter process comprising baking a solution of the above silicon-containing polyamic acid at 50.degree. to 500.degree. C.

Abstract: A crystalline polyimide polymer having a practical effectiveness that extrusion or injection molding which has so far been applied to thermoplastic resins, but could not have been achieved by conventional polyimides, are possible due to its melting point in the range of 300.degree. C. to 450.degree. C., and a process for producing the polymer, are provided, which polyimide polymer contains the following imide repetition unit (I) in 30% by mol based on the polymer and containing or not containing at least one of other imide repetition units and also having an inherent viscosity of 0.1 to 5 dl/g in conc. sulfuric acid at 30.+-.0.01.degree. C.: ##STR1## wherein X is divalent CO, divalent SO.sub.2 group, S, O or a single bond.

Abstract: A process for producing a silicon-containing polyamic acid of a specified inherent viscosity as a precursor affording polyimide resins having a considerable extent of heat resistance as adhesives or resins for multilayer laminated composite materials, and a good adhesion onto inorganic materials, metals or resins, and a crosslinked silicon-containing polyimide resin prepared from the polyamic acid are provided, which process comprises reacting a tetracarboxylic acid dianhydride of formula (1) (A mols), a diamine of formula (2) (B mols) and an aminosilicon compound of formula (3) (C mols), satisfying the expressions of (4) and (5): ##STR1## wherein R.sup.1 is a tetravalent carboxylic aromatic group; R.sup.2 is an aliphatic, alicyclic, aromatic aliphatic or carboyclic aromatic group each of a specified number of carbon atoms, a specified polysiloxane group, or a formula of ##STR2## wherein R.sup.8 is a specified hydrocarbon group or hydrogen atom; ##STR3## (s: 1 to 4); R.sup.

Abstract: A novel soluble polyimide-siloxane precursor having a good storage stability in solution and forming a superior coating on silicon wafer, glass, etc. under heating conditions of low temperature and short time; a process for producing the same; and a cross-linked polyimidesiloxane obtained by heating the above precursor are provided, which precursor hasan imide-amic acid chain part expressed by the formula (1) ##STR1## bonded by a bonding structure expressed by the formula (5)--SiR.sup.7.sub.3-k Y.sup.1.sub.k-1 --O--SiR.sup.7.sub.3-k Y.sup.1.sub.k-1 -- (5)wherein each I, in a total number of m+n+1, represents independently any one of constituting units expressed by the following formulas (2), (3) and (4): ##STR2## wherein R.sup.1 represents a tetravalent carbocyclic aromatic group; R.sup.2, R.sup.4, R.sup.5, R.sup.6, R.sup.7 and Y.sup.1 each are a specified group; l is 1 to 100; m is 0 or an integer; n is an integer; and 1.ltoreq.k.ltoreq.

Abstract: A novel soluble polyimide-siloxane precursor useful for forming a superior coating on silicon wafer, glass, etc. and a process for producing the same are provided, which precursor has an imide-amic acid chain part expressed by --R.sup.3 --(I)--R.sup.2 --(I)].sub.n R.sup.3 --, bonded by a bonding structure expressed by --SiR.sup.4.sub.3-m Y.sup.1.sub.m-1 --O--SiR.sup.4.sub.3-m Y.sup.1.sub.m-1 --, wherein (I) is either one of formulas (2), (3) or (4) ##STR1## wherein R.sup.1 is a tetravalent carbocyclic aromatic group; R.sup.2, R.sup.3, R.sup.4 and Y.sup.1 each are a specified group; 1.ltoreq.m.ltoreq.3; the precursor further being terminated by Y.sup.2.sub.m R.sup.4.sub.3-m Si-- wherein Y.sup.2 is a specified group and having a percentage imidization as defined relative to the quantities of (2), (3) and (4), of 50-100% and also an inherent viscosity as specifically defined, of 0.05 to 5 dl/g, the above n being an integer defined so as to give the above inherent viscosity value.

Abstract: A soluble imide oligomer represented by the general formula ##STR1## (Definitions of R, R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5, R.sup.6, R.sup.7 and R.sup.8 are found in the specification.) and its preparation process are presented. A coating solution for electronic materials containing said soluble imide oligomer is also presented.

Abstract: A silicon-containing step ladder polymer comprising a unit represented by the following general formula (I): ##STR1## a unit represented by the following general formula (II): ##STR2## and a unit represented by the following general formula (III): ##STR3## where R.sup.1 represents a hydrocarbon or fluorine-substituted hydrocarbon group, R.sup.2 represents hydrogen or a trialkyl siloxy group, and R.sup.3 and R.sup.4 which may be identical or different with each other represent individually hydrocarbon or fluorine-substituted hydrocarbon groups, the molar ratio of the unit (I) to the unit (II) is between 5:1-100:1 and the molar ratio of the unit (III) to the total amount of the unit (I)+unit (II) is between 1:5-1:100, as well as a process for producing such polymer.

Abstract: A silicone-polyimide precursor which affords a coating having a conspicuous adhesion onto silicon wafer, glass, etc. and also an improved strength, hardness, etc. after baking, and a process for producing the same are provided,which precursor is expressed by the formula (1) ##STR1## wherein R.sup.1 represents a tetravalent, carbocyclic aromatic group; R.sup.2, R.sup.3 and R.sup.6 are the same or different groups being 1.about.6 C alkyl, phenyl or alkyl-substituted phenyl of 7.about.12 C; R.sup.4 and R.sup.5 are the same or different groups being ##STR2## wherein s represents an integer of 1 to 4; said group ##STR3## has an average formula weight of 368 to 7,968; X represents alkoxy, acetoxy, halogen atom or hydroxy; ms at both the ends of the formula (1) independently represent an integer of 1 to 3; and l represents an integer of 1 to 30; andwhich process comprises reacting the following compounds (2), (3) and (4): ##STR4## wherein the symbols R.sup.1, etc.

Abstract: A silicon-containing step ladder polymer comprising a unit represented by the following general formula (I): ##STR1## a unit represented by the following general formula (II): ##STR2## and a unit represented by the following general formula (III): ##STR3## where R.sup.1 represents a hydrocarbon or fluorine-substituted hydrocarbon group, R.sup.2 represents hydrogen or a trialkyl siloxy group, and R.sup.3 and R.sup.4 which may be identical or different with each other represent individually hydrocarbon or fluorine-substituted hydrocarbon groups, the molar ratio of the unit (I) to the unit (II) is between 5:1-100:1 and the molar ratio of the unit (III) to the total amount of the unit (I)+unit (II) is between 1:5-1:100, as well as a process for producing such polymer.

Abstract: Polymers of .alpha.-olefin such as polyethylene, polypropylene, copolymers of ethylene with propylene, butene-1 or styrene, are produced by the (co-) polymerization using a catalyst obtained by mill-mixing an oxide of a metal belonging to I, II, III, VII or VIII Group of the Periodic Table of Elements such as MgO or SiO.sub.2 or B.sub.2 O.sub.3, with a trivalent metal halide such as AlCl.sub.3, then reacting the resultant mixture with a transition metal compound such as TiCl.sub.4 in the presence of an aromatic compound such as xylene, and activating the resultant solid reaction product with an organoaluminum compound such as triethyl aluminum.In the preparation of the present catalyst, no dehydrochlorination occurs. The present catalyst has an excellent utilization efficiency of transition metal compound in the polymerization. Further, no polymer film forms on the wall surface of the polymerization vessel.

Abstract: Ethylene can be polymerized or copolymerized by the use of a catalyst prepared by mixing a trivalent metal halide with a metal carbonate or/and a metal hydrogen carbonate, reacting the resulting mixture with a transition metal compound in the presence of an aromatic compound, and activating the resulting solid product with an organoaluminum compound.By substituting said metal carbonate or/and metal hydrogen carbonate for metal salt hydrates, sulfide hydrates, hydroxides or hydroxide hydrates, or metal oxides in our prior art, drawbacks such as dehydrochlorination in the preparation of catalyst or difficulty in removal of catalyst residue from polymer can be overcome while various advantages in our prior art are still maintained.