ADHERENCE SUBSTANCE, PRESSURE SENSITIVE ADHESIVE SHEET AND ITS USE

• US 20110111222A1
• Filed: 01/13/2011
• Published: 05/12/2011
• Est. Priority Date: 07/28/2008
• Status: Abandoned Application

• Current Assignee: Asahi Glass Company, Limited (AGC, Inc.)
• Original Assignee: Asahi Glass Company, Limited (AGC, Inc.)
• Inventors: Sato, Hisashi, Shimoma, Hitoshi, Yasuda, Teruhiko
• Application Number:
  US13/005,639
• Publication Number:
  US 20110111222A1
• Time in Patent Office: Days
• US Class Current: 428/355.R
• CPC Class Codes: C08G 65/336 containing silicon
• CPC Class Codes: C09J 167/00 Adhesives based on polyesters obtained by reactions forming a carboxylic ester link in the main chain based on polyester-amides C09J177/12; based on polyester-imides C09J179/08; Adhesives based on derivatives of such polymers
• CPC Class Codes: C09J 171/02 Polyalkylene oxides
• CPC Class Codes: C09J 201/10 containing hydrolysable silane groups
• CPC Class Codes: C09J 2467/00 Presence of polyester
• CPC Class Codes: C09J 2471/00 Presence of polyether
• CPC Class Codes: C09J 7/38 Pressure-sensitive adhesives [PSA]
• CPC Class Codes: Y10T 428/2852 Adhesive compositions

Abstract

To provide an adherence substance which has a low viscosity and good coatability, can be made solvent free, is less likely to undergo an increase in the adhesive strength with time and has good adhesion to an adherend while the adhesive strength is low, is excellent in removability and has a good wettability.

An adherence substance which is obtainable by curing a curable composition comprising a silyl group-containing polymer (S) represented by the formula (1) and which has a peel adhesive strength of at most 8 N/25 mm:

in the formula (1), R¹ represents a t-valent residue derived from a (mono)polyol; Q represents a bivalent group formed by a reaction of a terminal group selected from a hydroxy group, an amino group, an isocyanate group, an allyl group, an acryloyl group and a methacryloyl group, with a specific silyl compound; R³ represents a monovalent organic group; X represents a hydroxy group or a hydrolyzable group; Y represents a bivalent group containing an ester linkage or a bivalent group containing an ether linkage; a represents an integer of from 1 to 3; r represents an integer of from 1 to 1,000; and t represents an integer of from 1 to 8.

Claims

1. An adherence substance which is obtainable by curing a curable composition comprising a silyl group-containing polymer (S) represented by the following formula (1) and which has a peel adhesive strength of at most 8 N/25 mm:

2. The adherence substance according to claim 1, wherein the curable composition comprises, as the silyl group-containing polymer (S), a polyester ether type silyl group-containing polymer (S1) which is represented by the above formula (1) wherein r is an integer of from 2 to 1,000, and Y is a bivalent group represented by the formula (A) and a bivalent group represented by the formula (B).

3. The adherence substance according to claim 2, wherein the polyester ether type silyl group-containing polymer (S1) is a polymer obtainable via a first step of reacting an initiator (z) made of a compound having from 1 to 8 hydroxy groups in the molecule, a cyclic ester compound (a) having from 3 to 9 carbon atoms and an alkylene oxide (b) having from 2 to 4 carbon atoms in the presence of a polymerization catalyst to obtain a polyester ether poly(mono)ol (p1), a second step of introducing a connecting moiety to the terminal of the polyester ether poly(mono)ol (p1) to obtain a substituted polyester ether compound (p11), and a third step of reacting the substituted polyester ether compound (p11) with a silyl compound (I) to obtain the polyester ether type silyl group-containing polymer (S1).

4. The adherence substance according to claim 3, wherein in the polyester ether type silyl group-containing polymer (S1), the mass ratio of the bivalent group represented by the formula (A) derived from the cyclic ester compound (a) to the bivalent group represented by the formula (B) derived from the alkylene oxide (b) i.e. (A):

(B), is from 5;

95 to 95;

5.

5. The adherence substance according to claim 3, wherein the initiator (z) is a polyoxyalkylene poly(mono)ol (z2) which has from 1 to 8 hydroxy groups in the molecule and which also has an oxyalkylene group, and the polyester ether type silyl group-containing polymer (S1) is a polymer represented by the following formula (2):

6. The adherence substance according to claim 3, wherein the polyester ether poly(mono)ol (p1) has an average hydroxy value (OHV) of from 10 to 230 mgKOH/g.

8. A pressure sensitive adhesive sheet comprising a substrate layer and at least one layer of an adherence substance, wherein the adherence substance is one as defined in claim 1.

9. A backgrind tape comprising a substrate layer and at least one layer of an adherence substance, wherein the adherence substance is one as defined claim 1.

10. An optical element protective pressure sensitive adhesive sheet comprising a substrate layer and at least one layer of an adherence substance, wherein the adherence substance is one as defined in claim 1.

11. An optical element having the optical element protective pressure sensitive adhesive sheet as defined in claim 10 bonded thereon.

12. A light diffusing plate comprising the optical element as defined in claim 11.

13. A prism sheet comprising the optical element as defined in claim 11.

7. An adherence substance which is obtainable by curing a curable composition comprising a silyl group-containing polymer (S) represented by the following formula (1):