Abstract: The present invention provides a laminate comprising an insulating layer having suppressed dusting properties, an insulating film comprising the insulating layer, and an electronic circuit component comprising a pattern of the insulating layer. The laminate has a layer construction of first inorganic material layer-insulating layer-second inorganic material layer or a layer construction of inorganic material layer-insulating layer. The insulating layer comprises a laminate of two or more wet etchable insulating unit layers. At the interface between the inorganic material layer and the insulating layer, surface irregularities of the inorganic material layer have been transferred onto the surface of the insulating layer. The average height of the surface irregularities transferred onto the insulating layer is less than the thickness of the outermost insulating unit layer in the insulating layer.

Abstract: This invention relates to a laminate comprising an insulating polyimide resin layer etchable by an aqueous alkaline solution and a metal foil. The laminate has an insulating resin layer composed of a plurality of polyimide resin layers on the metal foil and the insulating resin layer has at least one polyimide resin layer (A) with a coefficient of linear thermal expansion (CTE) of 30×10?6/° C. or less and at least one polyimide resin layer (B) with a glass transition temperature (Tg) of 300° C. or below, the layer in contact with the metal foil is the polyimide resin layer (B), the bonding strength between the metal foil and the polyimide resin layer (B) in contact therewith is 0.5 kN/m or more, and the average rate of etching of the insulating resin layer by a 50 wt % aqueous solution of potassium hydroxide at 80° C. is 0.5 ?m/min or more. The laminate is useful for flexible printed circuits and the like.

Abstract: The present invention provides a laminate comprising an insulating layer having suppressed dusting properties, an insulating film comprising the insulating layer, and an electronic circuit component comprising a pattern of the insulating layer. The laminate has a layer construction of first inorganic material layer-insulating layer-second inorganic material layer or a layer construction of inorganic material layer-insulating layer. The insulating layer comprises a laminate of two or more wet etchable insulating unit layers. At the interface between the inorganic material layer and the insulating layer, surface irregularities of the inorganic material layer have been transferred onto the surface of the insulating layer. The average height of the surface irregularities transferred onto the insulating layer is less than the thickness of the outermost insulating unit layer in the insulating layer.

Abstract: This invention relates to an HDD suspension and a process for its manufacture with high productivity and reliability. The HDD suspension of this invention is manufactured from a laminate composed of a stainless steel substrate, an insulating resin layer and a metal foil by wet-etching the laminate by the use of a basic fluid. The insulating layer of the laminate is composed of plural layers of polyimide, every constituent layer exhibits a mean etching rate of 0.5 ?M/min or more by a 50 wt % aqueous solution of KOH at 80° C., the layers in contact with the stainless steel substrate and the metal foil are those of polyimide (B) exhibiting a glass transition temperature of 300° C. or less and the adhesive strength between the layer of polyimide (B) and either the stainless steel substrate or the metal foil is 0.5 kN/m or more.

Abstract: This invention relates to a laminate which changes in dimension to such a small extent as not to cause curling and warpage when the ambient humidity changes and is useful for flexible printed wiring boards. The laminate possesses a polyimide layer or layers of polyimides formed on a conductor by coating and at least one of the polyimide layers is composed of polyimide of low hygroscopic expansion obtained by the reaction of diamines containing 20 mol % or more of 4,4?-diamino-2,2?-dimethylbiphenyl with a tetracarboxylic acid compound and exhibiting a coefficient of linear hygroscopic expansion of 15×10?6/% RH or less.

Abstract: The present invention provides a laminate comprising an insulating layer having suppressed dusting properties, an insulating film comprising the insulating layer, and an electronic circuit component comprising a pattern of the insulating layer. The laminate has a layer construction of first inorganic material layer-insulating layer-second inorganic material layer or a layer construction of inorganic material layer-insulating layer. The insulating layer comprises a laminate of two or more wet etchable insulating unit layers. At the interface between the inorganic material layer and the insulating layer, surface irregularities of the inorganic material layer have been transferred onto the surface of the insulating layer. The average height of the surface irregularities transferred onto the insulating layer is less than the thickness of the outermost insulating unit layer in the insulating layer.

Abstract: This invention relates to a laminate comprising an insulating polyimide resin layer etchable by an aqueous alkaline solution and a metal foil. The laminate has an insulating resin layer composed of a plurality of polyimide resin layers on the metal foil and the insulating resin layer has at least one polyimide resin layer (A) with a coefficient of linear thermal expansion (CTE) of 30×10−6/° C. or less and at least one polyimide resin layer (B) with a glass transition temperature (Tg) of 300° C. or below, the layer in contact with the metal foil is the polyimide resin layer (B), the bonding strength between the metal foil and the polyimide resin layer (B) in contact therewith is 0.5 kN/m or more, and the average rate of etching of the insulating resin layer by a 50 wt % aqueous solution of potassium hydroxide at 80° C. is 0.5 &mgr;m/min or more. The laminate is useful for flexible printed circuits and the like.

Abstract: This invention relates to an HDD suspension and a process for its manufacture with high productivity and reliability. The HDD suspension of this invention is manufactured from a laminate composed of a stainless steel substrate, an insulating resin layer and a metal foil by wet etching the laminate by the use of a basic fluid. The insulating layer of the laminate is composed of plural layers of polyimide, every constituent layer exhibits a mean etching rate of 0.5 &mgr;m/min or more by a 50 wt % aqueous solution of KOH at 80° C., the layers in contact with the stainless steel substrate and the metal foil are those of polyimide (B) exhibiting a glass transition temperature of 300° C. or less and the adhesive strength between the layer of polyimide (B) and either the stainless steel substrate or the metal foil is 0.5 kN/m or more.

Abstract: This invention relates to laminates for use in HDD suspensions which are composed of a stainless steel base material and successive layers formed thereon of polyimides and an electrical conductor and in which the linear expansion coefficient of the polyimide layer is controlled in the range of 1×10−5/° C. to 3×10−5/° C. and the adhesive strength between stainless steel and polyimide and that between polyimide and electrical conductor are controlled at 0.5 kg/cm or more. This invention also relates to a process for preparing laminates for use in HDD suspensions comprising applying a solution of polyimide precursors or polyimides to a stainless steel base material with a thickness of 10 to 70 &mgr;m in one layer or more, drying, performing heat treatment at 250° C. or more to form a layer of polyimides with a thickness of 3 to 20 &mgr;m and a linear expansion coefficient of 1×10−5/° C. to 3×10−5/° C.

Abstract: This invention relates to heat-resistant film adhesives for use in fabrication of printed circuit boards formulated from polyimides with silicone units and epoxy resins and, if necessary, epoxy resin curing agents. It is possible to introduce functional groups reactive with epoxy resins into the polyimide structure. The films are used by inserting them between adherends and pressing at 1 to 1,000 kg/cm.sup.2 and 20.degree. to 250.degree. C. and they show excellent heat resistance, heat resistance at soldering temperature after moisture absorption and processibility when contact-bonded at 250.degree. C. or less.