Pressure-sensitive adhesive sheet and pressure-sensitive adhesive composition

Patent metadata

Field	Value
Publication number	US-2020017726-A1
Application number	US-201916505814-A
Country	US
Kind code	A1
Filing date	Jul 9, 2019
Priority date	Jul 10, 2018
Publication date	Jan 16, 2020
Grant date	—

Abstract

Provided is a PSA sheet that provides reliable adhesion even upon contact with grease. Provided is an adhesively double-faced PSA sheet having a PSA layer. The PSA sheet has an initial push-peel strength of 0.5 MPa or greater. It has an adhesive strength retention rate of 25% or higher, determined as the ratio of the push-peel strength at 24 hours after artificial sebum application to the push-peel strength before the artificial sebum application.

First claim

What is claimed is:

1 . A portable electronic device having a touch panel whose display also serves as an input device, wherein
the touch panel can be operated by direct finger touch, the portable electronic device has components bonded with a pressure-sensitive adhesive sheet the pressure-sensitive adhesive sheet is an adhesively double-faced PSA sheet having a pressure-sensitive adhesive layer, the pressure-sensitive adhesive sheet has an initial push-peel strength of 0.5 MPa or greater, the pressure-sensitive adhesive sheet has a push-peel strength at 24 hours after artificial sebum application, retaining at least 25% of the initial push-peel strength.

2 . The portable electronic device according to claim 1 , that is a portable phone.

3 . The portable electronic device according to claim 1 , that is a smartphone.

4 . The portable electronic device according to claim 1 , that is a tablet PC.

5 . The portable electronic device according to claim 1 , that is a wearable device.

6 . The portable electronic device according to claim 1 , that is a digital camera.

7 . The portable electronic device according to claim 1 , that is a portable music player.

8 . The portable electronic device according to claim 1 , that is a portable game device.

9 . The portable electronic device according to claim 1 , that is an electronic dictionary.

10 . The portable electronic device according to claim 1 , that is an electronic book.

11 . An adhesively double-faced pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer,
having an initial push-peel strength of 0.5 MPa or greater, and having a push-peel strength at 24 hours after artificial sebum application, retaining at least 25% of the initial push-peel strength.

12 . The pressure-sensitive adhesive sheet according to claim 11 , wherein the initial push-peel strength is 1 MPa or greater and the percent adhesive strength retained is 50% or higher.

13 . The pressure-sensitive adhesive sheet according to claim 11 , wherein the pressure-sensitive adhesive layer comprises an acrylic polymer as its base polymer.

14 . The pressure-sensitive adhesive sheet according to claim 11 , wherein the pressure-sensitive adhesive layer comprises a tackifier resin having a hydroxyl value of 120 mgKOH/g or greater.

15 . The pressure-sensitive adhesive sheet according to claim 14 , wherein the tackifier resin comprises a phenolic tackifier resin.

16 . The pressure-sensitive adhesive sheet according to claim 14 , wherein the tackifier resin content of the pressure-sensitive adhesive layer is 10 parts by weight or greater and 60 parts by weight or less to 100 parts by weight of the base polymer of the pressure-sensitive adhesive layer.

17 . The pressure-sensitive adhesive sheet according to claim 11 , having a substrate layer that supports the pressure-sensitive adhesive layer.

18 . The pressure-sensitive adhesive sheet according to claim 17 , wherein the substrate layer includes a resin film layer or a foam layer.

19 . The pressure-sensitive adhesive sheet according to claim 11 , used for bonding components of a portable electronic device.

20 . A pressure-sensitive adhesive composition comprising an acrylic polymer as its base polymer and a tackifier resin, wherein
the tackifier resin comprises a tackifier resin having a hydroxyl value of 120 mgKOH/g or greater.

Assignees

• Nitto Denko Corp

Inventors

• Ikami Toshiki
• Higuchi Naoaki
• Jozuka Kenta

Classifications

• C09J2400/243

  in the substrate · CPC title

• C09J7/26

  Porous or cellular plastics · CPC title

• C09J2433/00

  Presence of (meth)acrylic polymer · CPC title

• C09J7/30

  characterised by the adhesive composition · CPC title

• C09J2467/006

  in the substrate · CPC title