Composition and disassembling method

Provided is a composition which has excellent heat resistance and low outgas properties. A composition which contains components (A)-(D) described below and has a mass ratio (A)/(C) of from 3/1 to 8/1. (A) a polyfunctional (meth)acrylate such as a diene-based (meth)acrylate (B) (B1) a phenoxy (poly)alkylene oxide (meth)acrylate having an alkylene oxide chain and/or (B2) an alkyl (meth)acrylate having an alkyl group with 8-20 carbon atoms (C) a polyfunctional (meth)acrylate such as pentaerythritol tri(meth)acrylate (D) a radical photopolymerization initiator