Pressure-sensitive adhesive sheet for mobile electronic devices

Patent metadata

Field	Value
Publication number	US-2016222255-A1
Application number	US-201415021842-A
Country	US
Kind code	A1
Filing date	Sep 1, 2014
Priority date	Sep 17, 2013
Publication date	Aug 4, 2016
Grant date	—

Abstract

Provided is a PSA sheet for mobile electronic devices that has excellent drop impact resistance while being capable of exhibiting great holding power. This invention provides an adhesively double-faced PSA sheet used for fastening a component of a mobile electronic device. The PSA sheet comprises a PSA layer formed from a water-dispersed PSA composition. The water-dispersed PSA composition comprises a PSA polymer as its base polymer and a crosslinking agent. The PSA polymer has a glass transition temperature of −60° C. or lower.

First claim

1 . An adhesively double-faced pressure-sensitive adhesive sheet used for fastening a component of a mobile electronic device, the sheet comprising
a pressure-sensitive adhesive layer formed from a water-dispersed pressure-sensitive adhesive composition, wherein the water-dispersed pressure-sensitive adhesive composition comprises a pressure-sensitive adhesive polymer as its base polymer, and a crosslinking agent, and the pressure-sensitive adhesive polymer has a glass transition temperature of −60° C. or lower.

2 . The pressure-sensitive adhesive sheet according to claim 1 , wherein the water-dispersed pressure-sensitive adhesive composition comprises an isocyanate-based crosslinking agent as the crosslinking agent.

3 . The pressure-sensitive adhesive sheet according to claim 1 ,
wherein the pressure-sensitive adhesive layer has a weight ratio G B of ethyl acetate-insoluble portion of 15% to 45%.

4 . The pressure-sensitive adhesive sheet according to claim 1 , wherein the pressure-sensitive adhesive polymer is an acrylic polymer.

5 . The pressure-sensitive adhesive sheet according to claim 4 , wherein the acrylic polymer is obtained by polymerizing a starting monomer material comprising an alkyl acrylate having an alkyl group with 5 to 10 carbon atoms at or above 50% by weight.

6 . The pressure-sensitive adhesive sheet according to claim 1 , further comprising a substrate that supports the pressure-sensitive adhesive layer, the substrate being a resin film substrate.

7 . The pressure-sensitive adhesive sheet according to claim 1 , having a displacement distance from an initial position of 2 mm or less after one hour in a 40° C. holding power test carried out with a 500 g load applied.

8 . The pressure-sensitive adhesive sheet according to claim 1 , having a 180° peel strength to a polycarbonate plate of 10 N/20 mm or greater.

Assignees

• Nitto Denko Corp

Inventors

• Koso Masatsugu

Classifications

• C08G18/6229 Primary

  Polymers of hydroxy groups containing esters of acrylic or methacrylic acid with aliphatic polyalcohols · CPC title

• C09J2433/00

  Presence of (meth)acrylic polymer · CPC title

• C09J7/0264 Primary

  Chemistry & Metallurgy · mapped topic

• C09J2203/326

  for bonding electronic components such as wafers, chips or semiconductors · CPC title

• C09J2201/128

  Chemistry & Metallurgy · mapped topic