Nitto-denko Corporation

Hirofumi Katami

Atsushi Yasui

Takahiro Nonaka

Hiroyuki Takao

Toru Umemoto

Takami Hikita

Shinya Yamamoto

Shuhei Fukutomi

Shusaku Goto

Takeharu Kitagawa

Hiroaki Kishioka

Tomohide Banba

Shou Takarada

Masato Fujita

Hirotaka Ohara

A radiation curable pressure-sensitive adhesive sheetof the present invention has a pressure-sensitive adhesive layerthat is cured by irradiation with radiation. The pressure-sensitive adhesive layercontains a photopolymerization initiatorand a crosslinking agent, and the curing by irradiation with radiation is curing by a reaction between the photopolymerization initiatorand the crosslinking agent. In the radiation curable pressure-sensitive adhesive sheetof the present invention, when the pressure-sensitive adhesive layeris stored at 50° C. for 4 weeks, a rate of change in residual stress (N/cm) expressed by the following equation is 70% or less.Residual stress change rate (%)=(residual stress after storage at 50° C. for 4 weeks−initial residual stress)/(initial residual stress)×100

Radiation-curable adhesive sheet

A method for producing a pressure-sensitive adhesive sheet according to the present invention includes: forming a pressure-sensitive adhesive layerformed of a transparent base pressure-sensitive adhesive material on a support S; curing the pressure-sensitive adhesive layer; providing a solutionof an additive; applying the solutionto one of opposite surfaces of the cured pressure-sensitive adhesive layerto cause the additive contained in the solutionto infiltrate from the one surface in a thickness direction of the pressure-sensitive adhesive layer; and drying the pressure-sensitive adhesive layer

Method for producing pressure-sensitive adhesive sheet, and pressure-sensitive adhesive sheet

There is provided a polarizing plate with a retardation layer that can achieve an image display apparatus having excellent durability and excellent weatherability, and having an excellent hue. A polarizing plate with a retardation layer according to an embodiment of the present invention includes in this order: a polarizing plate including a protective layer and a polarizer; a retardation layer; and a pressure-sensitive adhesive layer. The protective layer has a light transmittance at a wavelength of 380 nm of 10% or less. The polarizing plate has a light transmittance at a wavelength of 380 nm of 5% or less. The pressure-sensitive adhesive layer has a light transmittance at a wavelength of 405 nm of 5% or less. The polarizing plate with a retardation layer has a light transmittance at a wavelength of 405 nm of 3% or less.

Polarizing plate with retardation layer and image display device

A laminate of optical elements comprises a transparent first optical element, a second optical element, and a transparent pressure-sensitive adhesive layer for bonding the first optical element to the second optical element. The pressure-sensitive adhesive layer comprises a base adhesive zone, a transparent refractive index-adjusting zone. The base adhesive zone is 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 facing the first optical element, in a thickness direction of the pressure-sensitive adhesive layer. The a transparent, adherent, refractive index-adjusting zone is formed over a given range from a second principal surface of the pressure-sensitive adhesive layer facing the second optical element.

Laminate of optical elements having a layer of a pressure-sensitive adhesive, and a method for producing such laminate of optical elements

Provided is a polarizing film laminate comprising: an element substrate; a polarizer; a transparent electroconductive layer patterned so as to function as a touch sensor; and a pressure-sensitive adhesive layer, wherein the adhesive layer comprises: a base adhesive zone made of a transparent base pressure-sensitive adhesive material and formed over a given range from the adhesive layer in a thickness direction of the adhesive layer; and a refractive index adjustment zone formed over a given range from the adhesive layer in the thickness direction and comprising the base adhesive material and material infiltrated into the base adhesive material and different from the base adhesive material, the refractive index adjustment zone having an average refractive index greater than a refractive index of the base adhesive material, and wherein the base adhesive material zone of the adhesive layer is located on the side of the element substrate.

Polarizing film laminate comprising transparent pressure-sensitive adhesive layer and patterned transparent electroconductive layer, liquid crystal panel and organic EL panel

Provided is a polarizing film laminate comprising a pressure-sensitive adhesive layer, and a polarizing film wherein the adhesive layer comprises: a base adhesive zone made of a transparent base pressure-sensitive adhesive material and formed over a given range from one principal surface of the adhesive layer in a thickness direction of the adhesive layer; and a refractive index adjustment zone formed over a given range from the other principal surface of the adhesive layer in the thickness direction and comprising the base pressure-sensitive adhesive material and material infiltrated into the base pressure-sensitive adhesive material and different from the base pressure-sensitive adhesive material, the refractive index adjustment zone having an average refractive index greater than a refractive index of the base pressure-sensitive adhesive material, and wherein the base pressure-sensitive adhesive material zone of the pressure-sensitive adhesive layer is located on the side of the polarizing film.

Polarizing film laminate having transparent adhesive layer, and display panel

The present invention provides a cover element having a pressure-sensitive adhesive sheet preliminarily laminated thereto, wherein the pressure-sensitive adhesive sheet comprises a pressure-sensitive adhesive layer in which a refractive index adjustment zone having a refractive index greater than that of a base pressure-sensitive adhesive material thereof is formed over a given range from a surface of the pressure-sensitive adhesive layer in a thickness direction thereof, whereby: in a lamination process of a customer which is a supply destination of the cover element, it becomes possible to eliminate a need to distinguish between obverse and reverse sides of the pressure-sensitive adhesive sheet itself; and, when the cover element is bonded to an optical element through the pressure-sensitive adhesive layer, it becomes possible to suppress internal reflection in a laminate formed of these optical elements.

Cover element provided with transparent pressure-sensitive adhesive layer

The present invention provides a transparent electroconductive layer-equipped cover element having a pressure-sensitive adhesive sheet preliminarily laminated thereto, wherein the pressure-sensitive adhesive sheet comprises a pressure-sensitive adhesive layer in which a refractive index adjustment zone having a refractive index greater than that of a base pressure-sensitive adhesive material thereof is formed over a given range from a surface of the pressure-sensitive adhesive layer in a thickness direction thereof, whereby: in a lamination process of a customer which is a supply destination of the transparent electroconductive layer-equipped cover element, it becomes possible to eliminate a need to distinguish between obverse and reverse sides of the pressure-sensitive adhesive sheet itself; and, when the transparent electroconductive layer-equipped cover element is bonded to an optical element through the pressure-sensitive adhesive layer, it becomes possible to suppress internal reflection in a laminate formed of these optical elements.

Transparent electroconductive layer-equipped cover element provided with transparent pressure-sensitive adhesive layer

In the case where a pressure-sensitive adhesive sheet comprising a pressure-sensitive adhesive layer having a refractive index adjustment zone is provided in such a manner that two PET separators are laminated to opposite surfaces of the pressure-sensitive adhesive layer, it is difficult to distinguish between obverse and reverse sides of the pressure-sensitive adhesive sheet itself. The present invention is directed to solving the above problems and, specifically, to offering a pressure-sensitive adhesive sheet having a refractive index adjustment zone capable of being easily produced at low cost, in a state in which it is preliminarily laminated with a substrate provided with an electroconductive layer, thereby making it possible to resolve complexity in handling (to easily distinguish between one surface defined by the refractive index adjustment zone and the other surface defined by the remaining zone).

Electroconductive film laminate comprising transparent pressure-sensitive adhesive layer

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.

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

As one sensor layer structure for a capacitive touch panel, a layer structure in which a transparent electroconductive layer is formed on each of opposite surfaces of a single film substrate, so-called GFD structure, is used. In the structure, for sufficiently suppressing internal reflection from the transparent electroconductive layer, it is necessary to employ a technique of forming one or more refractive index adjustment (IM) layers on each of the opposite surfaces of the single film substrate. This causes a problem that production yield is likely to deteriorate, and a production cost is increased. The present invention is directed to solving such a problem and, specifically, to laminating a refractive index adjustment zone-formed pressure-sensitive adhesive layer capable of being produced easily and at low cost, to each transparent electroconductive layer of a double-sided transparent electroconductive film, so as to effectively suppress internal reflection in the resulting laminate.

The present invention provides an excellent optical pressure-sensitive adhesive sheet having an excellent adhesion property to an optical member. The present invention relates to an optical pressure-sensitive adhesive sheet comprising a pressure-sensitive adhesive layer, wherein a relative dielectric constant at a frequency of 1 MHz is 5 to 10, and an adhesion strength to a glass, which is measured with a peel angle of 180&#xb0; and a tensile speed of 300 mm/min after 30 min of laminating the optical pressure-sensitive adhesive sheet to the glass, is 3 N/20 mm to 15 N/20 mm.

Optical pressure-sensitive adhesive sheet, liquid crystal display and input device comprising the same

An acrylic pressure-sensitive adhesive tape including an acrylic pressure-sensitive adhesive layer, wherein a 180&#xb0; peel adhesive force of the acrylic pressure-sensitive adhesive tape to a glass plate is 10 N/20 mm or more and a 180&#xb0; peel adhesive force of the acrylic pressure-sensitive adhesive tape to an acrylic plate is 10 N/20 mm or more. The acrylic pressure-sensitive adhesive layer contains an acrylic polymer (A), has a gel fraction of 65% or more, and has a 300% tensile residual stress of from 7 to 16 N/cm.

Growing community of inventors

Ibaraki, Japan

Hirofumi Katami