Resin composition for adhesive, adhesive containing resin composition for adhesive, adhesive sheet containing resin composition for adhesive, and printed wiring board including adhesive or adhesive sheet as adhesive layer
Provided is a resin composition for an adhesive comprising a polyurethane resin containing a carboxyl group, having specific range of an acid value having specific range of a number average molecular weight and having specific range of a glass transition temperature a polyester resin having specific range of a number average molecular weight and having specific range of a glass transition temperature; an epoxy resin containing a nitrogen atom; and an epoxy resin having a dicyclopentadiene skeleton, in which a content rate of the polyurethane resin to a sum of the polyurethane resin and the polyester resin is 70 to 95 percent by mass, a content rate of the total epoxy resin contained in the resin composition to the sum of the polyurethane resin and the polyester resin is 5 to 30 percent by mass.
1. A resin composition for an adhesive, comprising:
a polyurethane resin (a-1) containing a carboxyl group, having an acid value of not less than 100 equivalent/10 6 g and not more than 1000 equivalent/10 6 g, having a number average molecular weight of not less than 5.0×10 3 and not more than 1.0×10 5 , and having a glass transition temperature of 30° C. or more and 80° C. or less;
a polyester resin (a-2) having a number average molecular weight of not less than 5.0×10 3 and not more than 1.0×10 5 and having a glass transition temperature of −5° C. or less;
an epoxy resin (b) containing a nitrogen atom; and
an epoxy resin (c) having a dicyclopentadiene skeleton, wherein
a content rate of said polyurethane resin (a-1) to a sum of said polyurethane resin (a-1) and said polyester resin (a-2) is not less than 70 percent by mass and not more than 95 percent by mass,
a content rate of the total epoxy resin contained in the resin composition to the sum of said polyurethane resin (a-1) and said polyester resin (a-2) is not less than 5 percent by mass and not more than 30 percent by mass, and
a blending ratio of said epoxy resin (b) is not less than 0.1 percent by mass and not more than 20 percent by mass of the total epoxy resin contained in the resin composition.
2. The resin composition for an adhesive according to claim 1 , wherein said epoxy resin (b) has a glycidyl diamine structure.
3. The resin composition for an adhesive according to claim 1 , wherein a blending ratio of said epoxy resin (c) is not less than 60 percent by mass and not more than 99.9 percent by mass of the total epoxy resin contained in the resin composition.
4. The resin composition for an adhesive according to claim 1 , wherein said polyurethane resin (a-1) is obtained by a reaction of
polyester polyol (d),
a compound (e) having one carboxylic acid group and two hydroxyl groups, and
polyisocyanate (f).
5. The resin composition for an adhesive according to claim 1 , further containing an organic solvent.
6. An adhesive containing the resin composition for an adhesive according to claim 1 .
7. An adhesive sheet containing the resin composition for an adhesive according to claim 1 .
8. A printed wiring board including an adhesive layer made of the resin composition for an adhesive according to claim 1 .