Nitto-denko Corporation

Shouhei Wada

Akiko Takahashi

Toshihide Suzuki

Kenichi Yamamoto

Mitsuyoshi Shirai

Yutaka Tosaki

The present invention provides a water-dispersed acrylic PSA composition suitable for forming a PSA sheet. The PSA composition contains 100 parts by weight of an acrylic copolymer with a Tg of &#x2212;70&#xb0; C. to &#x2212;50&#xb0; C. obtained by polymerization of a monomer starting material containing 60 wt % or more of an alkyl (meth)acrylate with a Calkyl group and 5 wt % or less of a radical polymerizable monomer with a carboxyl group. When an adhesive sheet is formed therefrom, it exhibits an average SUS adhesive strength of 11 N/20 mm or greater, PP adhesive strength of 8.5 N/20 mm or greater, 80&#xb0; C. hold time of 1 hour or longer, and gap height of 10 mm or less in a curved surface adhesion test.

Pressure-sensitive adhesive composition and pressure-sensitive adhesive sheet

An adhesive sheet is provided in which properties that cause corrosion of a non-contacting metal are inhibited. The adhesive sheet is provided with a pressure-sensitive adhesive layer formed from an aqueous dispersion type adhesive composition. The pressure-sensitive adhesive composition contains an aqueous dispersion type acrylic polymer synthesized using a chain transfer agent that does not have sulfur as a composite element thereof. The amount of sulfur-containing gas (as SO) released from the pressure-sensitive adhesive sheet in the case of heating for 1 hour at 85&#xb0; C. is 0.043 &#x3bc;g/1 cmor less, adhesive strength on an ABS sheet is 10 N/20 mm or more, and holding time as determined in an 80&#xb0; C. cohesive strength test is 1 hour or more.

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Ibaraki, Japan

Shouhei Wada