Kuraray Co., Ltd.

Katsuyoshi Terao

Junnosuke Yamauchi

Hideo Takamatsu

Shobu Minatono

A pressure-sensitive adhesive composition based on liquid rubber, a cross-linking agent therefor and a tackifier, in which the liquid rubber component is a modified low molecular weight polyisoprene which is obtainable by adding 0.03 to 7 mol % of maleic anhydride or a derivative thereof, based on each isoprene monomer unit, to a low molecular weight polyisoprene having a molecular weight in the range of 10,000 to 90,000 is useful in producing a pressure-sensitive adhesive composition having very desirable tackiness, cohesive force and bonding characteristics without use of an organic solvent or with use of only a small amount of the solvent.

Pressure sensitive adhesive composition

A pressure-sensitive adhesive composition having excellent tackiness and improved thermal resistance comprises (A) a low molecular weight polyisoprene, which may be obtained by polymerizing isoprene monomer with the aid of a lithium-type catalyst, said polyisoprene having a cis-1,4 content of not less than 75%, a viscosity average molecular weight of 8,000 to 77,000 and an Mw/Mn value (Mw: weight average molecular weight; Mn: number average molecular weight) of 1.0 to 2.7 and (B) an elastomer.

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Ibaragi, Japan

Katsuyoshi Terao