Heat-peelable pressure-sensitive adhesive sheet

• US 6,998,175 B2
• Filed: 05/14/2001
• Issued: 02/14/2006
• Est. Priority Date: 05/15/2000
• Status: Expired due to Fees

• Current Assignee: Nitto Denko Corporation
• Original Assignee: Nitto Denko Corporation
• Inventors: Kiuchi, Kazuyuki, Arimitsu, Yukio, Murata, Akihisa, Oshima, Toshiyuki
• Primary Examiner(s): ZIRKER, DANIEL R
• Application Number:
  US09/853,787
• Publication Number:
  US 20010055678A1
• Time in Patent Office: 1,737 Days
• Field of Search: 428/40.1, 428/343, 428/346, 428/354, 428/355.R, 428/355.AC, 428/355.EN, 428/356, 428/922
• US Class Current: 428/354
• CPC Class Codes: C09J 2301/412 presence of microspheres
• CPC Class Codes: C09J 7/22 Plastics; Metallised plastics
• CPC Class Codes: C09J 7/38 Pressure-sensitive adhesives [PSA]
• CPC Class Codes: Y10S 428/922 Static electricity metal bleed-off metallic stock
• CPC Class Codes: Y10T 428/14 Layer or component removable to expose adhesive
• CPC Class Codes: Y10T 428/28 Web or sheet containing structurally defined element or component and having an adhesive outermost layer
• CPC Class Codes: Y10T 428/2813 Heat or solvent activated or sealable
• CPC Class Codes: Y10T 428/2848 Three or more layers
• CPC Class Codes: Y10T 428/2852 Adhesive compositions
• CPC Class Codes: Y10T 428/2857 including metal or compound thereof or natural rubber
• CPC Class Codes: Y10T 428/2878 including addition polymer from unsaturated monomer
• CPC Class Codes: Y10T 428/2891 including addition polymer from alpha-beta unsaturated carboxylic acid [e.g., acrylic acid, methacrylic acid, etc.] Or derivative thereof

Abstract

A heat-peelable pressure-sensitive adhesive sheet which, even when used for temporarily fixing electronic parts having poor resistance to static electricity, such as magnetic heads, is effective in preventing the yield of such electronic parts from being reduced by electrostatic breakage, while ensuring its functions of adhesiveness before heating and peelability after heating. The heat-peelable pressure-sensitive adhesive sheet comprises a substrate and formed on at least one side thereof a heat-expandable pressure-sensitive adhesive layer containing heat-expandable microspheres, wherein the heat-expandable pressure-sensitive adhesive layer has a surface resistivity of 10¹² Ω/□ or lower. In this heat-peelable pressure-sensitive adhesive sheet, the heat-expandable pressure-sensitive adhesive layer before heating may have a center line average surface roughness of 2 μm or less and a maximum surface roughness of 5 μm or less. The adhesive sheet may have a rubber-like organic elastic layer interposed between the substrate and the heat-expandable pressure-sensitive adhesive layer.

Claims

1. A heat-peelable pressure-sensitive adhesive sheet comprising a substrate and formed on at least one side thereof a heat-expandable pressure-sensitive adhesive layer containing heat-expandable microspheres, wherein the heat-expandable pressure-sensitive adhesive layer has a surface resistivity of 10¹² Ω

/□

or lower, and the heat-expandable pressure-sensitive adhesive layer before heating has a maximum surface roughness of 5 μ

m or less, and

wherein at least one selected from the group consisting of inorganic conductive materials, organic antistatic agents and organic conductive materials is contained in or applied to the heat-expandable pressure-sensitive adhesive layer.

2. The heat-peelable pressure-sensitive adhesive sheet as claimed in claim 1, wherein the heat-expandable pressure-sensitive adhesive layer before heating has a center line average surface roughness of 2 μ

m or less.

3. The heat-peelable pressure-sensitive adhesive sheet as claimed in claim 1, which further comprises a rubber-like organic elastic layer interposed between the substrate and the heat-expandable pressure-sensitive adhesive layer.

4. The heat-peelable pressure-sensitive adhesive sheet as claimed in claim 3, wherein the rubber-like organic elastic layer comprises a pressure-sensitive adhesive material.

5. The heat-peelable pressure-sensitive adhesive sheet as claimed in claim 1, wherein the at least one of inorganic conductive materials, organic antistatic agents and organic conductive materials is contained in the heat-expandable pressure-sensitive adhesive layer and is a conductive powder.

6. A heat-peelable pressure-sensitive adhesive sheet comprising a substrate and above at least one side thereof a heat-expandable pressure-sensitive adhesive layer containing heat-expandable microspheres, wherein the heat-expandable pressure-sensitive adhesive layer has a surface resistivity of 10¹² Ω

/□

or lower, and the heat-expandable pressure-sensitive adhesive layer before heating has a maximum surface roughness of 5 μ

m or less, and

wherein at least one selected from the group consisting of inorganic conductive materials, organic antistatic agents and organic conductive materials is applied to the substrate.

7. The heat-peelable pressure-sensitive adhesive sheet as claimed in claim 6, wherein an organic antistatic agent layer is formed on at least one side of the substrate.

8. The heat-peelable pressure-sensitive adhesive sheet as claimed in claim 6, wherein the heat-expandable pressure-sensitive adhesive layer before heating has a center line average surface roughness of 2 μ

m or less.

9. The heat-peelable pressure-sensitive adhesive sheet as claimed in claim 6, which further comprises a rubber-like organic elastic layer interposed between the substrate and the heat-expandable pressure-sensitive adhesive layer.

10. The heat-peelable pressure-sensitive adhesive sheet as claimed in claim 9, wherein the rubber-like organic elastic layer comprises a pressure-sensitive adhesive material.

11. The heat-peelable pressure-sensitive adhesive sheet as claimed in claim 6, wherein at least one selected from the group consisting of inorganic conductive materials and organic conductive materials is applied to the substrate.