GB2103633A

GB2103633A - Polyamide-imide compositions for imparting electrical properties and articles produced using the compositions

Info

Publication number: GB2103633A
Application number: GB08210524A
Authority: GB
Inventors: Kaoru Ohmura; Takeo Kimura; Ichiro Shibasaki
Original assignee: Asahi Chemical Industry Co Ltd; Asahi Kasei Kogyo KK
Current assignee: Asahi Kasei Corp; Asahi Chemical Industry Co Ltd
Priority date: 1978-04-28
Filing date: 1979-02-09
Publication date: 1983-02-23
Also published as: GB2103633B

Abstract

The compositions comprise an aromatic polyamide-imide with specified repeating units based on trimellitic anhydride together with a silane coupling agent to improve dispersibility and adhesion. The polyamide-imide is soluble in polar organic solvents and has a reduced viscosity of 0.3 to 1.5. Granular materials are dispersed in the composition to impart conductive, resistive or dielectric characteristics to coatings and substrates produced from the composition for use in printed circuit boards.

Description

SPECIFICATION Polyamide-imide compositions for imparting electrical properties and articles produced using the compositions This invention relates to compositions containing polyamide-imide resins which are used to provide electrically conductive, resistive, insulative or dielectric properties to articles for electrical use, such as circuit boards.

Recently, large integration and high reliability have been particularly required of electronic parts, and the development of materials having excellent thermal resistance, humidity resistance, adhesion and electrical characteristics which can be applied to the construction electronic parts has been desired, primarily because most of the known synthetic resins used for this purpose become unstable at temperatures above 250"C as their softening points are exceeded or their decomposition points approached. As such materials, the use of thermal resistance polymers may be considered. In general, however, thermal resistance polymers are insoluble in most solvents and must be used in the form of their precursors.For example, aromatic polyamide acids which are known as thermal resistance polymers are susceptible to hydrolysis and inferior in storage stability or must be converted by heat treatment into aromatic polyimides or aromatic polyamide-imides having thermal resistance at a temperature around 300"C. Accordingly, these aromatic polyamide acids cannot be applied to electronic parts which are affected by heat treatment. Further, contamination is caused by the low molecular weight compounds formed upon heat treatment.

Although polyimides and polyamide-imides which are partially soluble in solvents are also known, the practical features of most of the polyimidies and polyamide-imides, such as thermal resistance, humidity resistance and adhesion are inferior. Also, those polyimides and polyamide-imides synthesized at a temperature above 1 50 C are subject to partial hydrolysis and crosslinking, and it is difficult to obtain linear polymers having a reduced viscosity (or reduced specific viscosity i.e. specific viscosity divided by concentration of the solution) sufficient for producing the above described practical features. However, there have been various proposals to use polyamide-imide resins, in particular derived from trimellitic acid anhydride, as insulative coatings or films.

Further, compositions comprising silver particles and glass frits are known as compositions possessing electrical characteristics. However, these compositions finally require firing at a high temperature of about 500 to 1 0000C. Consequently it is difficult to obtain high accuracy and cost becomes high. Moreover, these compositions cannot be applied to substrates except thermal resistance substrates such as ceramics, nor to substrates mounted with electrical elements.

Our Patent Application No. 201 6487A discloses a variety of substrates such as insulative substrates, boards for circuits, electrically conductive circuit boards, electrically resistant circuit boards, multilayer circuit boards, hybrid circuit boards, mounting circuit boards and a variety of electrical elements obtained by using a composition comprising an aromatic polyamide-imide as an electrically conductive material, an electrically resistant material, a dielectric or insulative material, a protective material or a bonding material.

The present invention, which is divided from GB 20167487A provides a composition comprising 100 parts by weight of an aromatic polyamide-imide soluble in a polar organic solvent and having a reduced viscosity offrom 0.3 to 1.5 and repeating units of the formula,

or

wherein Ar is a divalent residue represented by the formula

Ar' is a divalent residue represented by the formula,

Ar" is a divalent residue represented by the formula,

and Ar"' is a divalent residue represented by the formula,

wherein R moieties may be the same or different and represent a hydrogen atom, a halogen atom or an alkyl group having 1 to 4 carbon atoms;X is an oxygen atom, a sulfur atom, a sulfonyl group, a carbonyl group, a carbonyloxy group, a methylene group, an ethylene group or a dimethylene group, and 2 to 60 parts by weight of a silane coupling agent.

The composition may also comprise, based on 100 parts by weight of the polyamide-imide, 100 to 4,000 parts by weight of a granular material which is at least one material selected from metals, metal oxides, metal nitrides, metal carbides, metal silicides, silicon, silicon oxides, silicon nitrides, silicon carbide, boron, boron nitrides and carbon uniformly dispersed therein so as to impart electrical conductive, resistive, dielectric or insulative characteristics to an article obtained using the composition.

The composition may also comprise, based on 100 parts by weight of the aromatic polyamide-imide, 10 to 10,000 parts by weight of at last one polar organic solvent selected from N,N-dimethylformamide, N,N-dimethyl-acetamide, dimethyl sulfoxide, N-methyl-2-pyrrolidone and hexamethyl phosphoramide.

The present invention further provides various substrates such as insulative substrates, boards or circuits, electrically conductive circuit boards, electrically resistant circuit boards, multilayer circuit boards, hybrid circuit boards, mounting circuit boards an various electrical elements such as condensers and electronic elements like integrated circuits, passive elements, active elements and conversion elements obtained by using the compositions described above.

Of the aromatic polyamide-imides as used in this invention, preferred ones are those in which Ar in the formulae as described above is:

Ar' is:

Ar" is:

Ar"' is:

wherein R is a hydrogen atom or a methyl group; and X is an oxygen atom, a sulfur atom, a sulfonyl group, a carbonyl group, a methylene group or an ethylene group.

More preferred polyamide-imides are those in which Ar in the formulae as described above is

Ar' is

and Ar" is

The aromatic polyamide-imides employed in this invention are preferably prepared in an organic solvent at a temperature below 150"C. When the preparation of the aromatic polyamide-imides is conducted at temperatures above 1 50"C, partial hydrolysis and cross-linking occur and as a result linear polymers having sufficient reduced viscosity for practical use cannot be obtained.Accordingly, the aromatic poly-amideimide employed in this invention are linear polymers having a reduced viscosity of from 0.3 to 1.5, preferably from 0.4 to 1.3, which have been prepared at a temperature below 150"C, preferably below 130"C. When the reduced viscosity of the aromatic polyamide-imides is less than 0.3, the strength of a laminate or a coating used as a protective material or an encapsulation material is low and other practical features are also insufficient and, most important of all, reliability is reduced. When the reduced viscosity is higher than 1.5, it becomes difficult to obtain a soution of a high concentration and thus the workability is decreased.

The reduced viscosity of the aromatic polyamide-imide as used throughtout this specification is measured at a concentration of 0.05 g of the aromatic polyamide-imide per 10 mt of N,N-dimethylformamide at 30"C.

More specifically, the aromatic polyamide-imides used in this invention can be prepared by (a) reacting an aromatic diamine of the formula,

with trimellitic anhydride monoacid chloride in a polar organic solvent at a temperature ranging from 0"Cto 150 C in the presence of a dehydrochlorination agent and a dehydration agent such as acetic anhydride-pyridine; (b) reacting a bisimidedicarboxylic acid of the formula

with diphenyl-3,3'-diisocyanate or m-phenylene di-isocyanate in a polar organic solvent at a temperature ranging from 1000C to 1 50 C or (c) reacting an aromatic diisocyanate of the formula, OCN {Ar,Ar' oral"} NCO with a bisimidedicarboxylic acid of the formula,

in an organic solvent at a temperature ranging from 1 O0C to 1 50 C.

In the above described formulae, R,X,Ar,Ar' and AR" are the same as defined above.

The polar organic solvents which can be employed in the preparation of the aromatic polyamide-imides to be used in this invention by the above described methods (a), (b) and (c) include N,N dimethylformamide,N,N-dimethylacetamide, dimethyl sulfoxide, N-methyl-2-pyrrolidone, hexamethylphos phoramide and any mixtures thereof.

Suitable dehydrochlorination agents employed in the above described method (a) include aliphatic tertiary amines such as trimethylamine, triethylamine, tri-n-propylamine, tri-n-butylamine, tri-sec-propylamine, allyldiethylamine, dimethyl-n-butylamine, diethyliso-propylamine, benzyldimethylamine, di-noctylbenzylamine, di-n-octylchlorobenzylamine, dimethylcyclohexylamine, dimethylphenethylamine, benzylmethylethylamine, (chlorophenethyl) bromobenzylamine, 1-dimethylamino-2-phenylpropane and 1 dimethylamino-4-pentane; cyclic tertiary amines such as pyridine, quinacridines, N-methylpyrrole, N methylpyrrolidine, N-methylpiperidine, quinoline, isoquinoline, N-methyltetrahydroquinoline, N methyltetrahydroisoquinoline and N-methylmorpholine; aromatic tertiary amines such as N,Ndimethylaniline and methyldiphenylamine; and any mixtures thereof.These dehydrochlorination agents can be used in an amount sufficient to neutralize the hydrogen chloride formed.

The total amount of the reactants based on the weight of the polar organic solvent which can be preferably employed in these methods (a), (b) and (c) ranges from 1 to 20 % by weight.

The reduced viscosity of the aromatic polyamide-imides can be controlled by the amount of the reactants to be reacted. In order to obtain a higher reduced viscosity the reactants are used in an equimolar amount.

When one reactant is used more than the other reactant, polymerization is suppressed, and accordingly the reduced viscosity of the aromatic polyamide-imide thus obtained can be controlled. Further, it is possible to control the reduced viscosity by capping the terminals of the aromatic polyamide-imide with a terminating agent such as phthalic anhydride.

The aromatic polyamide-imides used in this invention are soluble in N,N-dimethylformamide, N,Ndimethylacetamide, dimethyl sulfoxide, N-methyl-2-pyrrolidone, hexamethylphosphoramide and any mixture thereof. Of these polar organic solvents, N-methyl-2-pyrrolidone, hexamethylphosphoramide and any mixed solvent containing at least 5 percent by weight of N-methyl-2-pyrrolidone or hexamethylphosphoramide are preferred from the standpoint of practical features such as thermal resistance, humidity resistance, adhesion, electrical characteristics, as well as workability such as storage stability, coatability, laminatability and printability due to the crystallinity and internal stress of the aromatic polyamide-imides and the wettability of the compositions to articles to be applied therewith.

The amount of the polar organic solvent which can be employed in this invention typically ranges from 10 to 10,000 parts by weight per 100 parts by weight of the aromatic polyamide-imide. A preferred amount of the polar organic solvent ranges from 20 to 2,000 parts by weight per 100 parts by weight of the aromatic polyamide-imide. When the amount of the polar organic solvent is less than 10 parts by weight, the processability and the adhesion of the composition are reduced. When the amount is more than 10,000, the workability and the adhesion of the composition are reduced and pinholes are easily produced. Especially when the amount ranges from 20 to 200 parts by weight per 100 parts by weight of the aromatic polyamide-imide, the composition thus obtained becomes solid or semi-solid and can be melted by heating and, as a result, can be shaped, molded and bonded by heating.The temperture of heating for shaping, molding or bonding such a compositon is typically from 50 to 3000C and preferably from 100 to 200"C.

In the present invention the granular materials which can be dispersed in the aromatic polyamide-imide or in a composition comprising the aromatic polyamide-imide and the polar organic solvent to impart electrical characteristics thereto as specified include any materials capable of rendering the aromatic polyamide-imide or the composition electrically conductive, electrically resistant and dielectric or insulative.

In general, the shape or form of these granular materials may be spherical, square, needle-shaped or flaky if they are fine particles. The particle size of the granular materials typically ranges from 20 to 500 Il.

Suitable granular materials which can be employed in this invention include metals, metal oxides, metal nitrides, metal carbides, metal silicides, silicon, silicon oxide, silicon nitrides, silicon carbides, boron, boron nitrides, carbon and mixtures thereof.

Specific examples of suitable granular materials include Au, Ag, Pd, Ru, Pt, Rh, Ir, TI, Mo, Zn, Mn, Mg, Cd, Cr, Nb, Ge, Zr, Cu, Ni, Al, Sn, Pb, Bi, In, Fe, Co, Ti, W, Ta, Hf, Zr, Y, Ba, Be, Si, C, B, alloys thereof, oxides, nitrides, carbides and silicides thereof and mixtures thereof.

Of these materials, the materials which are preferably used as electrically conductive granular materials, used in this invention include, Au, Ag, Pd, Pt, Cu, Ni, Al, Sn, Mo, Mn, Co, W, alloys thereof and mixtures thereof. Of these electrically conductive granular materials, Au, Ag, Pd, Pt, Cu, Ni, Al, Sn, alloys thereof and mixtures thereof are more preferred.

The electrically resistant granular materials which can be preferably used in this invention include, Ag-PdO, Ag-PdO-Pd, NiO2-Ag, C-B-Ag, Ag-PdO-Sb2O3, C-B, Cu2O-CuO, In203, In203-Sb203, Tri203, SnO2, SnO2-Sb203, SnO2-Ta205, MoO3-B, ZnO, CdO-ZnO, IrO2, RhO, RuO2, TaN, TiN, Ti N-Ti, TaN-Ta, WC, WC-W, C, CoSi, TaSi, MnSi, MoSi, NiSi, TiSi and mixtures thereof.

The electrically insulative or dielectrical granular materials which are preferably used in this invention include, SiO, SiO2, Si3N4, SiC, Ta2O3, Awl203, TiO2, HfO2, ZrO2, Y203, BaTiO3, BN, BeO, CoO, PdO, B2O3, Bi203, BaO and mixtures thereof. Of these materials, SiO, SiO2, Si3N4, SiC, Ta2O3, Awl203, TiO2, BaTiO3, BN, BeO, CoO, PdO, B2O3, Bi203, BaO and mixtures thereof are more preferred.

The amount of the granular material which can be employed in this invention ranges from 100 to 4,000 parts by weight per 100 parts by weight of the polyamide-imide. A preferred amount of the granular material ranges from 200 to 2,00 parts by weight per 100 parts by weight of the polyamide-imide. When the amount of the granular material is less than 100 parts by weight, desirable electrical properties such as conductivity, resistance and the desirable dielectric properties cannot be obtained. On the other hand, when the amount of the granular material is more than 4,000 parts by weight in the case where the solvent is not employed, cracks are disadvantageously formed.

If necessary or desired, the compositions of this invention may additionally contain an epoxy resin for improving dispersibility of the granular material and adhesion of the compositions to articles to be applied therewith.

The amount of the silicane coupling agent is from 2 to 60 parts by weight per 100 parts by weight of the aromatic polyamide-imide. If the amount of the silane coupling agent or the epoxy resin is less than 2 parts by weight, the effect of using these materials cannot be observed. With amounts larger than 60 parts by weight of the coupling agent or 100 parts by weight of the epoxy resin, the thermal resistance is decreased.

The epoxy resins which can be used in this invention include any of the epoxy resins conventionally used for this purpose. Suitable examples of epoxy resins which can be used include those as disclosed in Hiroshi Kakiuchi as editor, Epoxy Resins, Chapters 3 & 4, Shokodo (1970). Such epoxy resins have at least two epoxy groups on the average per molecule and, as the residue or main chain, a carbon chain through an ether bond, an ester bond or an amino bond.

Suitable epoxy resins are obtained by reaction of a polyhydric alcohol such as ethylene glycol, glycerin, trimethylolpropane; a polyhydric phenol such as resorcinol, hydroquinone, catechol, fluoroglycinol; a polyphenol such as 2,2-bis(4-hydroxyphenyl)propane, 4,4'-dihydroxydiphenylmethane, novolak resin; a polycarboxylic acid such as p-hydroxybenzoic acid, terephthalic acid; or an amine such as o-toluidine; and excess amount of an epoxide such as epichlorohydrin, an alkylene oxide.

Many examples of these epoxy resins are described in U.S. Patent 2,592,560. More specifically, the epoxy resin obtained by reaction of Bisphenol A and epichloro-hydrin and represented by the formula:

wherein m1 is a number of 0 to 20, and a novolak-type epoxy resin obtained by reaction of a novolak resin and epichlorohydrin, represented by the formula:

wherein m1 is a number of 0 to 5, and preferably employed in this invention.

The composition of this invention comprising the granular material capable of imparting electrical characteristics thereto can be prepared by mixing the granular material obtained by pulverization, vacuum evaporation or chemical precipitation with the aromatic polyamide-imide and the polar organic solvent and dispersing the granular material into the polyamide-imide by stirring until the polyamide-imide is completely dissolved in the polar organic solvent. A ball mill can be used for dispersing. In this invention the granular material should be uniformly dispersed in the aromatic polyamide-imide and the polar organic solvent in such a manner as not to form lumps of the granular material.If necessary, when the solvent is removed from the composition thus obtained by evaporation, heat treatment or other methods, composition comprising the uniformly dispersed granular material will be obtained.

All of the compositions of this invention or to be used in this invention can be prepared at a temperature as low as around 100"C.

According to this invention, boards for circuits, electrically conductive circuit boards, electrically resistant boards, insulative substrates, multi-layer circuit boards, hybrid circuit boards, mounting circuit boards, condensers and electrical elements such as integrated circuits, passive elements, active elements and conversion elements can be prepared using the compositions of this invention.

The term "board for circuits" as used in the description of this invention denotes a base material whose entire surface is formed of a metal foil.

The term "circuit board" denotes a base material having only circuit thereon.

The term "electrically conductive circuit board" used herein denotes a base material on which an electrically conductive circuit is formed.

The term "electrically resistant circuit board" used herein denotes a base material having an electrically resistant circuit thereon.

The term "multi-layer circuit board" used herein denotes a base material having at least two electrically conductive circuits or at least two electrically resistant circuits through an insulation layer thereon.

The term "electrical element" used herein denotes an IC, a passive element, an active element and a conversion element, such as a monolithic IC, a hybrid IC, a resistor, a condenser, a coil, a diode, a transistor, a galvanomagnetic element, a photoelectric element, thermoelectric element, a piezoelectric element and a display element.

The term "mounting circuit board" used herein denotes a circuit board mounted with at least one electrical element thereon.

The term "hybrid circuit board" used herein denoted a base material having at least one electrically conductive circuit and at least one electrically resistant circuit thereon.

The insulative substrate can be prepared, for example, by impregnating a sheet of paper or a base material formed of glass fibers, glass coth or carbon fibers with a composition comprising the aromatic polyamide-imide and the polar organic solvent or the composition additionally comprising an insulative granular material and laminating a plurality of the impregnated base materials together, or by coating the composition over the entire surface of a base material such as a metal, plastics, glass or ceramic or coating or printing the composition pattern-wise on the base material, or by laminating a film obtained by removing the polar organic solvent from the composition over the entire surface of the base material or pattern-wise on the base material; or by molding the composition in a desired mold.

The board for circuits can be prepared, for example, by adhering a metal foil capable of being etched (e.g., copper foil) to the entire surface of a base material (e.g., a plastic film like a polyimide film) with the composition comprising the aromatic polyamide-imide and the polar organic solvent or the composition of this invention additionally comprising the insulative granular material. By etching the metal foil thus adhered in a desired pattern, there can be obtained a circuit board. By adhering a metal foil such as copper foil already cut in a circuit pattern to the base material with the composition there can also be obtained a circuit board.

The electrically conductive circuit board can be prepared, for example, by printing a composition comprising the aromatic polyamide-imdie, the polar organic solvent and the electrically conductive granular material on the insulative substrate in a circuit pattern and removing the polar organic solvent from the composition containing the conductive granular material by heating, or by laminating a film obtained by removing the polar organic solvent from the composition containing the conductive granular material on the insulative substrate in a circuit pattern.

The electrically resistant circuit board can be prepared, for example, by printing a composition comprising the aromatic polyamide-imide, the organic polar solvent and the electrically resistant granular material on the insulative substrate in a circuit pattern and removing the organic polar solvent from the composition by heating, or by laminating a film obtained by removing the polar organic solvent from the composition on the insulative substrate in a circuit pattern.

The multi-layer circuit board can be prepared, for example, by coating or printing a composition comprising the aromatic polyamide-imide and the polar organic solvent or the composition additionally comprising the insulative granular material over the entire surface of the electrically conductive circuit or the electrically resistant circuit or on the areas thereof to be multi-layered or pattern-wise on the electrically conductive circuit or the electrically resistant circuit in the case of through-hole connections and removing the polar organic solvent from the composition by heating, or by laminating a film obtained by removing the polar organic solvent from the composition over the entire surface of the electrically conductive circuit or electrically resistant circuit or pattern-wise on selected areas thereof to be laminated and further forming an electrically conductive circuit or an electrically resistant circuit thereon in the same manner as in preparing an electrically conductive circuit board or an electrically resistant board, The hybrid circuit board can be prepared by forming an electrically conductive circuit and an electrically resistant circuit on an insulative substrate in the same manner as in preparing the multi-layer circuit board.

The circuit board having a protective layer thereon can be prepared by coating or printing a composition comprising the aromatic polyamide-imide and the polar organic solvent or the composition additionally comprising the insulative granular material on at least part of the surface of the electrically conductive circuit board, the electrically resistant circuit board, the multi-layer circuit board or the hybrid circuit board and removing the polar organic solvent from the composition by heating, or by laminating a film obtained by removing the polar organic solvent from the composition over the entire surface of the aforementioned circuit board or pattern-wise on the surface of the above described circuit board.

The mounting circuit board can be prepared by bonding electrical elements to the circuit of the circuit board with a composition comprising the aromatic polyamide-imide, the polar organic solvent and the electrically conductive granular material by a method such as die bonding, or by bonding the electrical elements to the insulative substrate with a composition comprising the aromatic polyamide-imide, the polar organic solvent and the insulative granular material and then bonding the electrical elements to a circuit on the insulative substrate by a method such as wire bonding.

The condenser can be prepared by coating or printing a composition comprising the aromatic polyamide-imide, the polar organic solvent and the dielectric granular material uniformly dispersed therein on an electrode such as a metal and then providing another electrode thereon and removing the polar organic solvent from the composition by heating, or by laminating a film obtained by removing the polar organic solvent from the composition on an electrode and then providing another electrode thereon, or by evaporating or spattering a metal on both surfaces of a film obtained by removing the polar organic solvent from the composition, or by coating or printing a composition comprising the aromatic polyamide-imide, the polar organic solvent and the electrically conductive granular material uniformly dispersed therein on both surfaces of the film and removing the polar organic solvent from the composition by heating.

The electrical element having a lead wire can be prepared by bonding the electrical elements such as integrated circuits, passive elements, active elements and conversion elements to a lead wire such as a metal frame with a composition comprising the aromatic polyamide-imide, the polar organic solvent and the electrically conductive granular material and removing the polar organic solvent from the composition by heating.

The encapsulated electrical elements can be prepared by immersing integrated circuits, passive elements, active elements and conversion elements in a composition comprising the aromatic polyamide-imide and the polar organic solvent or the composition additionally comprising the insulative granular material uniformly dispersed therein and removing the polar organic solvent from the composition by heating.

The compositions as described have excellent thermal resistance, humidity resistance, adhesion, storage stability and electrical characteristics, and also the various substrates, circuit boards and electrical elements obtained by using the compositions have excellent thermal resistance, humidity resistance and high accuracy and reliability. Especially thermal resistance and humidity resistance are important to electronic parts from the standpoint of reliability.

The following Examples are given to illustrate the present invention more specifically. All parts in these Examples are by weight.

Electrical resistances in these Examples are measured by "Universal Digital Meter 2502" (trade name, manufactured by Uokogawa Electric Works Ltd.).

Example 1 100 parts of an aromatic polyamide-imide having a reduced viscosity of 0.7 synthesized from a bisimidedicarboxy-lic acid prepared from 4,4'-diaminodiphenyl sulfone and trimellitic anhydride and 3,3'-diisocyanatodiphenyl were added with 5 parts of a silane coupling agent trade name "A-l 100", manufactured by Nippon Unicar Co. Ltd.) and 400 parts by weight of dimethyl sulfoxide and dissolved therein. Then to the solution were added 500 parts of fine gold particles having an average particle diameter of 5 p and uniformly dispersed by a ball mill to give a paste. The paste thus obtained was screen-printed on an alumina base plate to form 20 electrically conductive lines having a width of 1 mm, a length of 2 cm and a thickness of about 50 F and then subjected to heat treatment at 1 50 C for 30 minutes.The resistance was 0.2 9 or less and the adhesion was good.

Further, in order to test the thermal resistance of the line, the resulting article was subjected to heat treatment at 400"C for one hour. The electrical resistance of the line thus treated was 0.2 Q or less, and the lines did not peel from the base plate and their adhesion was excellent.

Example 2 A paste was prepared by uniformly dispersing 400 parts of fine aluminium oxide particles having an average particle diameter of 0.8 11 in a solution of 100 parts of an aromatic polyamide-imide having a reduced viscosity of 1.0 synthesized from a bisimidedicarboxylic acid having been prepared from 4,4'diaminodiphenyl ether and trimellitic anhydride and 3,3'-diisocyanate diphenyl, 2 parts of a silane coupling agent (trade name "A-l 100", manufactured by Nippon Unicar Co. Ltd.), 10 parts of an epoxy resin (trade name "AER-669", manufactured by Asahi Chemical Industry Co. Ltd.) and 500 parts of N-methyl-2pyrrolidone. The paste thus obtained was coated on the entire surface of an alumina base plate at a thickness of 5 and then subjected to heat treatment of 1 50"C for 30 minutes to given an insulative substrate. The insulative substrate thus obtained withstood thermal resistance test at 400 C and the adhesion was good.

Claims

1. A composition comprising 100 parts by weight of an aromatic polyamide-imide soluble in a polar organic solvent and having a reduced viscosity of from 0.3 to 1.5 and repeating units of the formula,

wherein Ar is a divalent residue represented by the formula,

Ar' is a divalent residue represented by the formula,

Ar" is a divalent residue represented by the formula,

and AR" is a divalent residue represented by the formula,

wherein R moieties may be the same or different and represent a hydrogen atom, a halogen atom or an alkyl group having 1 to 4 carbon atoms; Xis an oxygen atom, a sulfur atom, a sulfonyl group, a carbonyl group, a carbonyloxy group, a methylene group, an ethylene group or a dimethylmethylene group, and 2 to 60 parts by weight of a silane coupling agent.

2. A composition according to claim 1, further comprising additionally 100 to 4,000 parts by weight of a granular material which is at least one material selected from metals, metal oxides, metal nitrides, metal carbides, metal silicides, silicon, silicon oxides, silicon carbide, silicon nitrides, boron, boron nitrides and carbon uniformly dispersed therein.

3. A composition according to claim 2, wherein the granular material is at least one of Au, Ag, Pd, Pt, Cu, Ni, Al, Sn and alloys thereof.

4. A composition according to claim 2, wherein the granular material is at least one of Ag-PdO, Ag-PdO-Pd, NiO2-Ag, C-B-Ag, Ag-PdO-Sb203, C-B, Cu2O-cuO, In203, In203-Sb203, To203, SnO2, SnO2-Sb203, SnO2-Ta205, MoO3-B, ZnO, CdO-ZnO, RuO2, TaN, TiN, TiN-Ti, TaN-Ta, WC, WC-W, C, CoSi, ZrSi, TaSi, MnSi, MoSi, NiSi and TiSi.

5. A composition according to claim 2, wherein the granular material is at least one of SiO, SiO2, Si3N4, SiC, Ta2O3, Al203, Tit2, BaTiO3, BN, BeO, CoO, PdO, B203, Bi203 and BaO.

6. A composition according to any one of claims 1 to 5, comprising additionally 10 to 10,000 parts by weight of at least one solvent selected from N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, N-methyl-2-pyrrolidone and hexamethylphosphoramide.

7. A composition according to claim 6, wherein the solvent comprises at least 5% by weight of N-methyl-2-pyrrolidone or hexamethylphosphoramide.

8. A composition according to claim 6 or 7, wherein the amount of the solvent ranges from 20 to 200 parts by weight.

9. A composition according to claim 1, substantially as described in either of the Examples.

10. An insulative substrate comprising a base material formed of paper or fiber impregnated with a composition claimed in claims 1 or 5, in any one or claims 6 to 8 when appended to claim 1 or 5.

11. An insulative substrate comprising a base material printed, coated or laminated over at least part of the suface of the base material with a composition as claimed in claims 1 or 5 or in any one of claims 6 to 8 when appended to claims 1 or 5.

12. A board for circuits comprising an insulative base material and a layer of metal foil, said metal foil being adhered to the surface of the base material with a composition as claimed in claims 1 or 5 or in any one of claims 6 to 8 when appended to claims 1 or 5.

13. A circuit board comprising a base material and circuit on the base material, at least a portion of the circuit being coated with a composition as claimed in claims 1 or 5 or in any one of claims 6 to 8 when appended to claims 1 or 5.

14. A multi-ayer circuit board comprising a circuit board as claimed in claim 13 and a circuit on the composition-coated surface of the circuit board.

15. A mounting circuit board comprising an insulative substrate and at least one electrical element selected from integrated circuits, passive elements, active elements and conversion elements, the electrical element being bonded to the insulative substrate with a composition as claimed in claims 1 or 5 or in any one of claims 6 to 8 when appended to claims 1 or 5.

16. A hybrid circuit board comprising an insulative substrate having on the surface thereof in a pattern a composition as claimed in claims 3 or 4 or in any one of claims 6 to 8 when appended to claims 3 or 4.

17. A condenser comprising two electrodes united by a composition as claimed in claims 1 or 5 or in any one of claims 6 to 8 when appended to claims 1 or 5.

18. An electrical element selected from integrated circuits, passive elements, active elements and conversion elements which is encapsulated in a composition as claimed in claims 1 or 5 or in any one of claims 6 to 8 when appended to claims 1 or 5.

19. A circuit board comprising an insulative substrate and a layer of metal foil in a circuit pattern adhered to the insulative substrate by a composition as claimed in claims 1 or 5 or in any one of claims 6 to 8 when appended to claims 1 or 5.

New claims or amendments to claims filed on Superseded claims 1 New or amended claims: CLAIMS

wherein Ar is

Ar' is

Ar"is

Ar"' is

wherein R moieties may be the same or different and represent a hydrogen atom, or a methyl group; X is an oxygen atom, a sulfur atom, a sulfonyl group, a carbonyl group, a methylene group or an ethylene group; and 2 to 60 parts by weight of a silane coupling agent.