Pressure-sensitive adhesive sheet having a transparent pressure-sensitive adhesive layer

Patent metadata

Field	Value
Publication number	US-2016115357-A1
Application number	US-201514890470-A
Country	US
Kind code	A1
Filing date	Jan 16, 2015
Priority date	Jan 17, 2014
Publication date	Apr 28, 2016
Grant date	—

Abstract

A pressure-sensitive adhesive sheet comprises a support and a transparent pressure-sensitive adhesive layer on the support. The pressure-sensitive adhesive layer comprises a base adhesive zone made essentially of a transparent base pressure-sensitive adhesive material and formed over a given range from a first principal surface of the pressure-sensitive adhesive layer in a thickness direction of the pressure-sensitive adhesive layer, and a transparent, adherent, refractive index-adjusting zone formed over a given range from a second principal surface of the pressure-sensitive adhesive layer in the thickness direction, and wherein the refractive index-adjusting zone has a refractive index greater than a refractive index of the base pressure-sensitive adhesive material.

First claim

1 - 16 . (canceled)

17 . A pressure-sensitive adhesive sheet comprising a support and a transparent pressure-sensitive adhesive layer on the support, wherein the pressure-sensitive adhesive layer comprises:
a base adhesive zone made essentially of a transparent base pressure-sensitive adhesive material and formed over a given range from a first principal surface of the pressure-sensitive adhesive layer in a thickness direction of the pressure-sensitive adhesive layer; and a transparent, adherent, refractive index-adjusting zone formed over a given range from a second principal surface of the pressure-sensitive adhesive layer in the thickness direction, the refractive index-adjusting zone having a refractive index greater than that of the base pressure-sensitive adhesive material.

18 . The pressure-sensitive adhesive sheet as recited in claim 17 , wherein said support comprises a releasable sheet.

19 . The pressure-sensitive adhesive sheet as recited in claim 18 , wherein said support comprising a releasable sheet is disposed on each side of said pressure-sensitive adhesive layer.

20 . The pressure-sensitive adhesive sheet as recited in claim 17 , wherein the refractive index-adjusting zone has a thickness of 20 nm to 600 nm.

21 . The pressure-sensitive adhesive sheet as recited in claim 1 , wherein the refractive index-adjusting zone is formed by dispersing, in a pressure-sensitive adhesive material identical to the base pressure-sensitive adhesive material, particles of a high refractive index material having a refractive index greater than that of the pressure-sensitive adhesive material, to thereby increase an average refractive index of the refractive index-adjusting zone.

22 . The pressure-sensitive adhesive sheet as recited in claim 21 , wherein the refractive index of the high refractive index material particles is in the range of 1.60 to 2.74.

23 . The pressure-sensitive adhesive sheet as recited in claim 21 , wherein the second principal surface of the refractive index-adjusting zone has a region where the high refractive index material particles are exposed to the second principal surface, and a matrix region where the pressure-sensitive adhesive material of the refractive index-adjusting zone is exposed to the second principal surface.

24 . The pressure-sensitive adhesive sheet as recited in claim 21 , wherein the high refractive index material particles have an average primary particle size of 3 nm to 100 nm as measured by TEM observation.

25 . The pressure-sensitive adhesive sheet as recited in claim 21 , wherein a difference in refractive index between the high refractive index material particles and the base pressure-sensitive adhesive material is in the range of 0.15 to 1.34.

26 . The pressure-sensitive adhesive sheet as recited in claim 21 , wherein the high refractive index material is one or more compounds selected from the group consisting of TiO 2 , ZrO 2 , CeO 2 , Al 2 O 3 , BaTiO 3 , Nb 2 O 5 and SnO 2 .

27 . The pressure-sensitive adhesive sheet as recited in claim 17 , wherein the refractive index-adjusting zone is formed by adding, to a pressure-sensitive adhesive material identical to the base pressure-sensitive adhesive material, an organic material having a refractive index greater than that of the pressure-sensitive adhesive material, in the form of particle, polymer or oligomer, to thereby increase an average refractive index of the refractive index-adjusting zone.

28 . The pressure-sensitive adhesive sheet as recited in claim 27 , wherein the refractive index of the base pressure-sensitive adhesive material is in the range of 1.40 to 1.55, and the refractive index of the organic material is in the range of 1.59 to 2.04.

29 . The pressure-sensitive adhesive sheet as recited in claim 17 , wherein the pressure-sensitive adhesive layer has a total light transmittance of 80% or more.

30 . The pressure-sensitive adhesive sheet as recited in claim 21 , wherein the high refractive index material particles partially exist in the form of an aggregate as a result of aggregation of two or more of the particles.

31 . The pressure-sensitive adhesive sheet as recited in claim 21 , wherein the refractive index-adjusting zone exists with irregular depths in the thickness direction of the pressure-sensitive adhesive layer.

32 . A method of producing a pressure-sensitive adhesive sheet, comprising:
forming a pressure-sensitive adhesive layer made essentially of a transparent base pressure-sensitive adhesive material on a support; providing a dispersion liquid containing a refractive index-adjusting material having a refractive index greater than that of the base pressure-sensitive adhesive material in a dispersed manner; applying the dispersion liquid to one of opposite surfaces of the pressure-sensitive adhesive layer to cause the refractive index-adjusting material particles contained in the dispersion liquid to infiltrate from the one surface in a thickness direction of the pressure-sensitive adhesive layer; drying the resulting pressure-sensitive adhesive layer to volatilize a liquid part of the dispersion liquid; and attaching a releasable sheet to the other surface of the pressure-sensitive adhesive layer.

33 . The method as recited in claim 32 , wherein the refractive index-adjusting material is particles of a high refractive index material having a refractive index greater than that of the pressure-sensitive adhesive material.

34 . The method as recited in claim 32 , wherein the refractive index-adjusting material is an organic material having a refractive index greater than that of the base pressure-sensitive adhesive material, in the form of particle, polymer or oligomer.

Assignees

• Nitto Denko Corp

Inventors

• Katami Hirofumi
• Umemoto Toru
• Takao Hiroyuki
• Nonaka Takahiro
• Yasui Atsushi
• Hikita Takami

Classifications

• C08K3/22

  of metals · CPC title

• C08K2003/2241

  Titanium dioxide · CPC title

• C09J7/241

  Polyolefin, e.g.rubber · CPC title

• C09J7/20

  characterised by their carriers · CPC title

• C09J2203/318

  for the production of liquid crystal displays · CPC title