Nitto-denko Corporation

Hideyuki Tokuyama

Kazumichi Kato

Kohei Doi

Mitsuhiro Kanada

Toru Iseki

Tadao Takahashi

Makoto Saito

Kunio Nagasaki

Kiichiro Matsushita

Tetsuya Otsuka

Mika Okada

Tsunaki Kitahara

Provided is an adsorption temporary fixing sheet having a sufficient shear adhesive strength in a direction parallel to its surface, and having a weak adhesive strength in a direction vertical to the surface. Also provided is a method of producing such adsorption temporary fixing sheet. The adsorption temporary fixing sheet includes a foam layer including an open-cell structure, wherein, when a silicon chip vertical adhesive strength of a surface of the foam layer after 20 hours at each of such different temperatures as &#x2212;40&#xb0; C., 23&#xb0; C., or 125&#xb0; C. is represented by V1 (N/1 cm&#x25a1;), V2 (N/1 cm&#x25a1;), or V3 (N/1 cm&#x25a1;) and when a silicon chip shearing adhesive strength of the surface of the foam layer after 20 hours at each of the different temperatures (&#x2212;40&#xb0; C., 23&#xb0; C., or 125&#xb0; C.) is represented by H1 (N/1 cm&#x25a1;), H2 (N/1 cm&#x25a1;), or H3 (N/1 cm&#x25a1;), relationships of V1&#x3c;H1, V2&#x3c;H2, and V3&#x3c;H3 are satisfied.

Adsorptive temporary fixing sheet and method for manufacturing same

Provided is a foam sheet that can raise an electrostatic capacitance at the time of compression, and hence can improve sensitivity when used for an electrostatic capacitance sensor. The foam sheet includes: a foam layer; and a pressure-sensitive adhesive layer arranged on at least one side of the foam layer, wherein the foam sheet has a dielectric constant increase amount Q-P at 10% compression of 0.2 (F/m) or more, where P (F/m) represents a dielectric constant of the foam sheet immediately after the foam sheet has been left at rest under conditions of a temperature of 23&#xb0; C. and a humidity of 50% for 2 hours, and Q (F/m) represents a dielectric constant of the foam sheet at a time when the foam sheet is compressed by 10% immediately after being left at rest under the conditions of a temperature of 23&#xb0; C. and a humidity of 50% for 2 hours.

Foam sheet

Provided is an adsorption temporary fixing sheet having a sufficient shear adhesive strength in a direction parallel to its surface, having a weak adhesive strength in a direction vertical to the surface, and having excellent antistatic performance. The adsorption temporary fixing sheet includes a foam layer including an open-cell structure, and has a surface resistivity of from 1.0&#xd7;10to 1.0&#xd7;10&#x3a9;/&#x25a1;, wherein, when a silicon chip vertical adhesive strength of a surface of the foam layer after 18 hours at each of such different temperatures as &#x2212;30&#xb0; C., 23&#xb0; C., or 80&#xb0; C. is represented by V1, V2, or V3 (N/1 cm), and when a silicon chip shearing adhesive strength of the surface of the foam layer after 18 hours at each of such different temperatures as &#x2212;30&#xb0; C., 23&#xb0; C., or 80&#xb0; C. is represented by H1, H2, or H3 (N/1 cm&#x25a1;), relationships of V1&#x3c;H1, V2&#x3c;H2, and V3&#x3c;H3 are satisfied.

Adsorptive temporary fixing sheet

There is provided a foamed sheet which takes only a short time to recover the thickness thereof after being compressed, and even if being subjected to repeated impacts, hardly decreases in the impact absorption. The foamed sheet according to the present invention comprises a foamed body formed of a resin composition comprising: a thermoplastic resin a and a silicone-based compound b having not more than 2,000 siloxane bonds; and/or a thermoplastic resin a' having a silicone chain having not more than 2,000 siloxane bonds. The thermoplastic resin a is preferably at least one selected from the group consisting of acrylic polymers, rubbers, urethanic polymers and ethylene-vinyl acetate copolymers. The silicone-based compound b is preferably at least one selected from the group consisting of silicone oils, modified silicone oils and silicone resins.

Foamed sheet

A foamed sheet according to the present invention has a thickness of 30 to 500 &#x3bc;m and includes a foam. The foam has a density of 0.2 to 0.7 g/cm, an average cell diameter of 10 to 150 &#x3bc;m, and a peak top of loss tangent (tan &#x3b4;) occurring in a temperature range of from &#x2212;30&#xb0; C. to 30&#xb0; C., where the loss tangent is defined as the ratio of a loss modulus to a storage modulus determined at an angular frequency of 1 rad/s in dynamic viscoelastic measurement of the foam. The foam preferably has a maximum of the loss tangent (tan &#x3b4;) in the temperature range of from &#x2212;30&#xb0; C. to 30&#xb0; C. of 0.2 or more.

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Ibaraki, Japan

Hideyuki Tokuyama