| 摘要 |
PURPOSE:To improve the film forming property when a protective surface film for a printed wiring board is formed, by adding a reaction product of a specified diol with a specified isocyanate and a specified acrylic or methacrylic monoester, a specified linear polymer, and a specified sensitizer. CONSTITUTION:A diol such as 1,4-butanediol is reacted with 1.2-1.6 isocyanate equiv. of an isocyanate such as isoboron diisocyanate basing on 1.0 OH equiv. of said diol and 0.2-0.3 OH equiv. of the (meth)acrylic ester of a diol basing on 1.0 OH equiv. of said diol to prepare a reaction product. A photosensitive resin composition is composed essentially of 100pts.wt. said reaction product, 5- 400pts.wt. linear polymer such as polymethyl (meth)acrylate with 40-80 deg.C glass transition temp., and a sensitizer which generates free radicals when irradiated with active light. The photosensitive resin composition is easily coated on a substrate or the like, has a favorable film forming property, and gives a protective surface film with superior bendability, heat resistance and solvent resistance by development. |
