Pressure-sensitive adhesive sheet

Patent metadata

Field	Value
Publication number	US-2018194975-A1
Application number	US-201815862989-A
Country	US
Kind code	A1
Filing date	Jan 5, 2018
Priority date	Jan 10, 2017
Publication date	Jul 12, 2018
Grant date	—

Abstract

Provided is a PSA sheet highly durable against repeated deformation and suited for use in a flexible device as well. The PSA sheet provided by this invention comprises a PSA layer. The PSA sheet shows a recovery rate at 100% elongation of 70% or higher. The PSA layer shows a displacement of 0.5 mm or greater according to the following holding power test:
<Holding Power Test>
At 23° C., the PSA layer is applied over a 10 mm wide by 20 mm long bonding area to a Bakelite plate as an adherend; a 1 kg load is applied in the length direction; after one hour, the displacement from the initial position where first applied is determined.

First claim

What is claimed is:

1 . A pressure-sensitive adhesive sheet comprising a pressure-sensitive adhesive layer, wherein
the PSA sheet shows a recovery rate at 100% elongation of 70% or higher, and the pressure-sensitive adhesive layer shows a displacement of 0.5 mm or greater according to the following holding power test:
<Holding Power Test>
At 23° C., the pressure-sensitive adhesive layer is applied over a 10 mm wide by 20 mm long bonding area to a Bakelite plate as an adherend; a 1 kg load is applied in the length direction; after one hour, the displacement from the initial point where first applied is determined.

2 . The pressure-sensitive adhesive sheet according to claim 1 , showing a maximum tensile strength at 100% elongation of 15 N/10 mm or less.

3 . The pressure-sensitive adhesive sheet according to claim 1 , having a thickness of 250 μm or less.

4 . The pressure-sensitive adhesive sheet according to claim 1 , wherein the pressure-sensitive adhesive layer is formed of a pressure-sensitive adhesive comprising a base polymer and a tackifier resin.

5 . The pressure-sensitive adhesive sheet according to claim 4 , wherein
the tackifier resin comprises a tackifier resin T L having a softening point of 50° C. or higher and lower than 105° C., and the tackifier resin T L content in the pressure-sensitive adhesive layer is greater than 10 parts by weight to 100 parts by weight of the base polymer.

6 . The pressure-sensitive adhesive sheet according to claim 4 , wherein the base polymer is an acrylic polymer.

7 . The pressure-sensitive adhesive sheet according to claim 1 , wherein the pressure-sensitive adhesive layer comprises a crosslinking agent.

8 . The pressure-sensitive adhesive sheet according to claim 1 , wherein the pressure-sensitive adhesive layer shows a distance returned of 0.05 mm or greater at 5 minutes after the load is removed in the holding power test.

9 . The pressure-sensitive adhesive sheet according to claim 1 , comprising a substrate and the pressure-sensitive adhesive layer provided at least on one face of the substrate.

10 . The pressure-sensitive adhesive sheet according to claim 9 , wherein the substrate is a stretchable substrate comprising, as its primary component, a resin selected from the group consisting of polyurethane, polyolefin and olefinic elastomer.

11 . The pressure-sensitive adhesive sheet according to claim 4 , wherein the base polymer has a glass transition temperature of −25° C. or lower.

12 . The pressure-sensitive adhesive sheet according to claim 5 , wherein
the tackifier resin T L content is 15 parts by weight or greater to 100 parts by weight of the base polymer.

13 . The pressure-sensitive adhesive sheet according to claim 12 , wherein the tackifier resin T L comprises a rosin-based resin.

14 . The pressure-sensitive adhesive sheet according to claim 12 , wherein the tackifier resin T L accounts for 30% by weight or more of all the tackifier resin in the pressure-sensitive adhesive.

15 . The pressure-sensitive adhesive sheet according to claim 7 , wherein the crosslinking agent comprises an isocyanate-based crosslinking agent.

16 . The pressure-sensitive adhesive sheet according to claim 15 , wherein the base polymer of the pressure-sensitive adhesive forming the pressure-sensitive adhesive layer is an acrylic polymer, the acrylic polymer is a polymer of a monomer mixture comprising a hydroxy group-containing monomer, the isocyanate-based crosslinking agent is used in an amount up to 40 times that of the hydroxy group-containing monomer.

17 . The pressure-sensitive adhesive sheet according to claim 1 , having a maximum tensile strength of 7 N/10 mm or less.

18 . The pressure-sensitive adhesive sheet according to claim 1 , having an elongation at break of 200% or greater.

19 . The pressure-sensitive adhesive sheet according to claim 1 , having a thickness of 30 μm or greater.

20 . The pressure-sensitive adhesive sheet according to claim 1 for use in a flexible device.

Assignees

• Nitto Denko Corp

Inventors

• Yamanari Yusuke
• Saito Makoto
• Higuchi Naoaki
• Jozuka Kenta

Classifications

• C09J7/255

  Polyesters · CPC title

• C09J2475/006

  in the substrate · CPC title

• C09J2433/00

  Presence of (meth)acrylic polymer · CPC title

• C09J7/25

  based on macromolecular compounds obtained otherwise than by reactions involving only carbon-to-carbon unsaturated bonds · CPC title

• C09J2467/006

  in the substrate · CPC title