| US 7,514,143 B2 | ||
| Re-peelable pressure-sensitive adhesive sheet | ||
| Takeshi Matsumura, Ibaraki (Japan); Kouji Akazawa, Ibaraki (Japan); Kazuyuki Kiuchi, Ibaraki (Japan); and Tomokazu Takahashi, Ibaraki (Japan) | ||
| Assigned to Nitto Denko Corporation, Osaka (Japan) | ||
| Filed on Aug. 05, 2004, as Appl. No. 10/912,615. | ||
| Claims priority of application No. 2003-206670 (JP), filed on Aug. 08, 2003. | ||
| Prior Publication US 2005/0031861 A1, Feb. 10, 2005 | ||
| Int. Cl. B32B 7/12 (2006.01); B05D 5/10 (2006.01) | ||
| U.S. Cl. 428—354 [428/343; 428/41.7; 428/41.8; 427/208.4] | 13 Claims |
| 1. A re-peelable pressure-sensitive adhesive sheet, comprising an adhesive layer formed over a base film and at least one
intermediate layer between the base film and the adhesive layer,
wherein the intermediate layer comprises materials which have a function of relieving thermal contraction stress generated
under 100-200° C. heat treatment, wherein said material is a viscoelastic sheet or a thermoplastic resin,
wherein said intermediate layer comprises polyisobutylene;
wherein, the intermediate layer has a storage elastic modulus (G′) of 3.0×104 to 1.0×108 Pa at 23° C. at the intermediate layer and a storage elastic modulus (G′) of 1.0×103 to 8.0×104 Pa at 200° C. at the intermediate layer, and
wherein the base film has a heat shrinkage ratio, in both MD and TD directions, of less than 2% at 200° C. heat treatment
for 2 hours.
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