Thermosetting composition for protective film for wiring board

Abstract

Disclosed is a thermosetting composition for a protective film for a wiring board, which has excellent low warpage properties, flexibility, and long-term insulation reliability. The thermosetting composition for a protective film for a wiring board comprises, as essential components, an epoxy group-containing compound having a tricyclodecane structure, polyurethane having a structural unit represented by formula (1) and having a functional group which can react with an epoxy group, and a solvent. In formula (1), R1 represents an alkylene group having 3 to 18 carbon atoms, and n represents an integer of 1 or more. As the epoxy group-containing compound having a tricyclodecane structure, a compound represented by formula (2) is preferably used.

Description

technical field [0001] The present invention relates to a new thermosetting composition for a protective film of a wiring board, a protective film of a wiring board obtained by curing the thermosetting composition for a protective film, a flexible wiring board covered with the protective film, and a flexible wiring board covered with the protective film. A method of manufacturing a flexible wiring board. More specifically, the present invention relates to a thermosetting composition for a protective film of a wiring board having low warpage, flexibility, and excellent long-term electrical insulation reliability, and a protective film for a wiring board obtained by curing the thermosetting composition for a protective film. , a flexible wiring board partially or entirely covered with the protective film, and a method for manufacturing the flexible wiring board covered with the protective film. Background technique [0002] Conventionally, the surface protective film of flexi...

AI Technical Summary

Problems solved by technology

Therefore, the current situation is that curable coating agents cannot meet the required performance in terms of flexibility and warpage caused by curing shrinkage.

[0004] For example, JP-A-11-61038 (Patent Document 1) discloses a resin composition using a polybutadiene-blocked isocyanate and a polyol. Although the cured product is excellent in flexibility and shrinkage, But the heat resistance is not enough

[0005] In Japanese Unexamined Patent Publication No. 2004-137370 (Patent Document 2), a composition comprising a polyamide-imide resin made of polycarbonate diol and an amine-type epoxy resin is disclosed. It is obtained by reacting two-terminal diisocyanate polyurethane obtained by reacting with a diisocyanate compound and trimellitic acid, but has the electrical characteristics of a cured product obtained by polyamide-imide resin and amine-type epoxy resin. The long-term reliability is not good. full of such flaws

[0006] In Japanese Patent Laying-Open No. 2006-307183 (Patent Document 3), a composition comprising carboxyl-containing polyurethane polyimide and epoxidized polybutadiene is disclosed, but the composition has the following defects: When the composition is dried to remove the solvent, carboxyl group-containing polyurethane polyimide and epoxidized polybutadiene tend to have a phase-separated structure, making it difficult to form a uniform film

[0007] In addition, in Japanese Patent Laid-Open No. 2004-182792 (Patent Document 4), a polyamide-imide resin having an organosiloxane skeleton is disclosed, but the cured product has poor adhesion to the substrate, and it is necessary to use Special solvents such as N-methyl-2-pyrrolidone sometimes dissolve the emulsion during screen printing, which sometimes becomes a problem

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