Adhesive sheet, laminate for touch panel, and capacitance-type touch panel

Patent metadata

Field	Value
Publication number	US-10125294-B2
Application number	US-201514851217-A
Country	US
Kind code	B2
Filing date	Sep 11, 2015
Priority date	Mar 13, 2013
Publication date	Nov 13, 2018
Grant date	Nov 13, 2018

Abstract

In an adhesive sheet, temperature dependence of a relative dielectric constant that is determined by a test for evaluating temperature dependence is equal to or less than 30%, and a 180° peel strength determined by a test for evaluating adhesiveness is equal to or greater than 0.20 N/mm. The adhesive sheet can inhibit the occurrence of malfunctioning of a capacitance-type touch panel in an environment of a wide temperature range from a low temperature to a high temperature, and can be included in a laminate for a touch panel and a capacitance-type touch panel.

First claim

What is claimed is:

1. An adhesive sheet,
wherein temperature dependence of a relative dielectric constant of the adhesive sheet, which is determined by a test for evaluating temperature, is equal to or less than 30%, a 180° peel strength of the adhesive sheet, which is determined by a test for evaluating adhesiveness is equal to or greater than 0.20 N/mm,
wherein the adhesive sheet is obtained by forming an adhesive composition comprising at least one (meth)acrylate monomer, at least one tackifying agent, and at least two rubber components in the form of film and polymerizing the adhesive composition with light or heat,
wherein the at least two rubber components contain a rubber component having a polymerizable group and another rubber component having no polymerizable group,
wherein a content of the at least two rubber components in the adhesive composition are 70 parts by mass to 320 parts by mass with respect to 100 parts by mass of the at least one (meth)acrylate monomer,
wherein a content of the at least one tackifying agent in the adhesive composition is 80 parts by mass to 320 parts by mass with respect to 100 parts by mass of the at least one (meth)acrylate monomer,
in the test for evaluating temperature dependence, the adhesive sheet is sandwiched between aluminum electrodes, a temperature of the adhesive sheet is increased by 20° C. from −40° C. to 80° C., a relative dielectric constant of the adhesive sheet at each temperature is calculated by measuring impedance at 1 MHz, a minimum value and a maximum value are selected from calculated relative dielectric constants, and a value (%) calculated by an equation of [(maximum value−minimum value)/minimum value×100] is determined to be the temperature dependence, and
in the test for evaluating adhesiveness, the adhesive sheet is bonded to a glass substrate, and the 180° peel strength of the adhesive sheet is determined based on JIS 0237.

2. The adhesive sheet according to claim 1 ,
wherein the maximum value of the relative dielectric constants calculated at temperatures increased by 20° C. from −40° C. to 80° C. is equal to or less than 3.8.

3. The adhesive sheet according to claim 2 , comprising:
an adhesive in which a ratio of a value of inorganicity to a value of organicity is 0.05 to 0.3,
wherein the ratio represents the value of inorganicity/the value of organicity.

4. The adhesive sheet according to claim 1 , comprising:
an adhesive in which a ratio of a value of inorganicity to a value of organicity is 0.05 to 0.3,
wherein the ratio represents the value of inorganicity/the value of organicity.

5. A laminate for a touch panel, comprising:
the adhesive sheet according to claim 1 ; and
a capacitive touch panel sensor.

6. The laminate for a touch panel according to claim 5 , further comprising:
a protective substrate,
wherein the capacitive touch panel sensor, the adhesive sheet, and the protective substrate are laminated on each other in this order.

7. A capacitive touch panel, having at least:
a display apparatus;
the adhesive sheet according to claim 1 ; and
a capacitive touch panel sensor in this order.

8. The capacitive touch panel according to claim 7 ,
wherein a size of an input area, which can detect a contact state with an object, of the capacitive touch panel sensor is equal to or greater than 5 inches in a diagonal direction.

9. A laminate for a touch panel, comprising:
the adhesive sheet according to claim 2 ; and
a capacitive touch panel sensor.

10. A laminate for a touch panel, comprising:
the adhesive sheet according to claim 4 ; and
a capacitive touch panel sensor.

11. A capacitive touch panel, having at least:
a display apparatus;
the adhesive sheet according to claim 2 ; and
a capacitive touch panel sensor in this order.

12. A capacitive touch panel, having at least:
a display apparatus;
the adhesive sheet according to claim 4 ; and
a capacitive touch panel sensor in this order.

Assignees

• Fujifilm Corp

Inventors

• Mitamura Yasuhiro
• Shibata Michihiro
• Ogikubo Shinya

Classifications

• G06F3/044

  by capacitive means · CPC title

• C09D4/06

  {Organic non-macromolecular compounds having at least one polymerisable carbon-to-carbon unsaturated bond} in combination with a macromolecular compound other than an unsaturated polymer of groups C09D159/00 - C09D187/00 · CPC title

• H03K17/962

  Capacitive touch switches · CPC title

• G06F3/047

  using sets of wires, e.g. crossed wires · CPC title

• C09J109/00

  Adhesives based on homopolymers or copolymers of conjugated diene hydrocarbons · CPC title