Removable adhesive composition, removable adhesive layer, adhesive sheet, and surface protective material

A re-peeling pressure-sensitive adhesive composition, which is used for a surface protecting material for an adherend having a photocatalytic layer, comprising:

• a (meth)acryl-based polymer;
• and
• a surfactant having a molecular weight of 150 to 5000, in an amount from 0.01 to 30 parts by weight with respect to 100 parts by weight of the (meth)acryl-based polymer,
• wherein the (meth)acryl-based polymer comprises, as monomer units:
• 50 to 99.9% by weight of (A) at least one acrylate-based monomer represented by the following general formula (1):
• CH2═CR1COOR2, wherein R1 represents a hydrogen atom or a methyl group, and R2 represents an alkyl group having 2 to 14 carbon atoms;
• 0.1 to 10% by weight of (B) a functional-group-containing vinyl-based monomer;
• and
• 0 to 49.9% by weight of (C) a vinyl-based monomer copolymerizable with the component (A) and/or the component (B).

A method of protecting the surface of an object having a photocatalytic layer, comprising:

• providing an object having a photocatalytic layer;
• and
• contacting the surface of said object having a photocatalytic layer with a re-peeling pressure-sensitive adhesive composition,
• wherein the re-peeling pressure-sensitive adhesive composition comprises:
• a (meth)acryl-based polymer comprising, as monomer units,
• 50 to 99.9% by weight of (A) at least one acrylate-based monomer represented by the following general formula (1):
• CH2═CR1COOR2,
• wherein R1 represents a hydrogen atom or a methyl group, and R2 represents an alkyl group having 2 to 14 carbon atoms,
• 0.1 to 10% by weight of (B) a functional-group-containing vinyl-based monomer, and
• 0 to 49.9% by weight of (C) a vinyl-based monomer copolymerizable with the component (A) and/or the component (B);
• and
• (D) a surfactant having a molecular weight of 150 to 5000, the amount of the component (D) being from 0.01 to 30 parts by weight with respect to 100 parts by weight of the (meth)acryl-based polymer.