Surface-protective pressure-sensitive adhesive sheet and pressure-sensitive adhesive composition for surface-protective pressure-sensitive adhesive sheet

A pressure-sensitive adhesive sheet for surface protection, which comprises a substrate containing an ethylene/propylene copolymer and an ethylene/1-butene copolymer in a weight ratio of 60:40 to 90:

• 10, wherein said ethylene/propylene copolymer has a melt flow rate measured at 230° C. under a load of 2.16 kg of 0.5 to 5 g/10 min.

A pressure-sensitive adhesive sheet for surface protection, which comprises a substrate containing an ethylene/propylene copolymer and an ethylene/1-butene copolymer in a weight ratio of 60:40 to 90:10, wherein said ethylene/1-butene copolymer has a melt flow rate measured at 190° C. under a load of 2.16 kg of 0.1 to 20 g/10 min.

An adhesive composition for pressure-sensitive adhesive sheets for surface protection, which comprises 5 to 30 parts by weight of a rosin resin tackifier based on 100 parts by weight of a blend comprising 50 to 100% by weight of a polyisobutylene and/or a butyl rubber and 50 to 0% by weight of a polybutene.

A pressure-sensitive adhesive sheet for surface protection, which comprises:

• a substrate comprising an ethylene/propylene copolymer and an ethylene/1-butene copolymer in a weight ratio of 60:40 to 90:10;
• and
• an adhesive layer formed on said substrate, which comprises 100 parts by weight of a blend comprising 50 to 100% by weight of a polyisobutylene and/or a butyl rubber and 50 to 0% by weight of a polybutene and 5 to 30 parts by weight of a rosin resin tackifier.