Pressure-sensitive adhesive tape or sheet

摘要

The present invention relates to a pressure-sensitive adhesive tape or sheet comprising: a viscoelastic layer containing bubbles and/or fine particles; and a pressure-sensitive adhesive layer formed on at least one side of the viscoelastic layer and formed from a pressure-sensitive adhesive composition comprising a monomer mixture comprising the following (a1), (a2) and (a3) or partially polymerized product thereof, and thermal-expandable fine particles:
(a1) alkyl (meth)acrylate monomer having 4 to 12 carbon atoms in its alkyl moiety and having a glass transition temperature when formed into a homopolymer of lower than 0°C;
(a2) monomer having at least one nitrogen atom and one ethylenically unsaturated bond in its molecule; and
(a3) monomer having one ethylenically unsaturated bond in its molecule and having a glass transition temperature when formed into a homopolymer of 0°C or higher (excluding (a2) above).