Abstract: A removable adhesive composition comprising (i) 100 parts by weight of a copolymer (A) which is tacky at ordinary temperature, synthesized of 90 to 99.9% by weight of a nonfunctional vinyl type monomer (a) mainly composed of an acrylate or methacrylate ester having an alkyl group having 2 to 12 carbon atoms and 0.1 to 10% by weight of a functional vinyl type monomer (b) having one or more of a carboxyl group, a hydroxyl group, an amino group or an epoxy group in its molecule; (ii) 20 to 1,000 parts by weight of a copolymer (B) whose glass transition point is 10.degree. C. or less and also having a mean particle diameter of 0.5 to 300 .mu.m, synthesized of 90 to 99.9% by weight of a nonfunctional vinyl type monomer (a) mainly composed of acrylate or methacrylate ester having an alkyl group having 2 to 12 carbon atoms and 0.1 to 10% by weight of an .alpha.-monoolefinic carboxylic acid (c); and (iii) 0.

Abstract: Disclosed is a removable adhesive sheet or tape which comprises adhesive fine particles attached on at least one side of a substrate through a primer resin layer comprising at least one selected from the group consisting of a poly (vinylidene chloride) resin, a poly (vinyl acetate) resin having a polymerization degree of 400 or more, a polyamide resin having a melting point of 80.degree. C. or less, a poly (vinyl chloride-vinyl acetate) type resin, a phenol-modified epoxy resin and a maleated natural rubber.According to the present invention, a removable adhesive sheet or tape which is excellent in removability even after frequent repetition of bonding to and removal from an adherend can be obtained.

Abstract: To prevent the growth of aquatic animals and plants on the surfaces of underwater structures, the surfaces are covered with a protective adhesive sheet comprised of a copper-nickel alloy plate having a weight ratio of copper:nickel in the range of 100:0 to 80:20, a primer layer formed on the alloy plate, and a pressure-sensitive adhesive layer formed on the primer layer. Prior to applied the adhesive sheet, the surface to be protected is preferably cleaned and coated with a primer of the same composition as that of the primer layer of the adhesive sheet.

Abstract: A removable adhesive sheet comprising a substrate (A) and an adhesive composition layer which comprises elastic micro-balls (B) and an adhesive (C), the adhesive composition layer being formed on an adhesive layer forming surface of the substrate, wherein the mixing proportion of the elastic micro-balls (B) to the adhesive (C) in the adhesive composition layer is 1:10 to 10:1 in terms of weight ratio, and the protrusive areas of the elastic micro-balls (B) partially protruding from the surface of the adhesive composition layer is entirely covered with the adhesive (C) has an adhesion capability that is not lowered through a frequent repetition of bonding to and removing from an adherend.