Photocurable composition, sealing agent, and cured product

Patent metadata

Field	Value
Publication number	US-12497477-B2
Application number	US-202117995988-A
Country	US
Kind code	B2
Filing date	Apr 14, 2021
Priority date	Apr 16, 2020
Publication date	Dec 16, 2025
Grant date	Dec 16, 2025

Abstract

A photocurable composition contains components (A) to (D). The composition contains 1 to 50 parts by mass of the following component (B) and 50 to 300 parts by mass of the component (C) relative to 100 parts by mass of the following component (A). The component (A) is a polyisobutylene having a (meth)acryloyl group in its molecule. The component (B) is a urethane-modified (meth)acrylate oligomer (excluding the component (A)). The component (C) is a (meth)acrylate monomer (excluding the component (A) and the component (B)). The component (D) is a photoinitiator.

First claim

The invention claimed is:

1 . A photocurable composition comprising the following components (A) to (D), and containing 1 to 50 parts by mass of the following component (B) and 50 to 300 parts by mass of the component (C) relative to 100 parts by mass of the following component (A);
component (A): a polyisobutylene having a (meth)acryloyl group in its molecule component (B): a urethane-modified (meth)acrylate oligomer that is different from the component (A) component (C): a (meth)acrylate monomer that is different from the component (A) and the component (B) component (D): a photoinitiator, wherein the photocurable composition has a structural viscosity ratio in a range from 3.0 or more to less than 5.5, the structural viscosity ratio being defined as a viscosity measured at a shear rate of 2 s −1 divided by a viscosity measured at a shear rate of 20 s −1 , both of the viscosities being measured at 25° C. using a cone-plate viscometer.

2 . The photocurable composition according to claim 1 , comprising 10 to 30 parts by mass of the component (B) relative to 100 parts by mass of the component (A).

3 . The photocurable composition according to claim 1 , comprising 100 to 200 parts by mass of the component (C) relative to 100 parts by mass of the component (A).

4 . The photocurable composition according to claim 1 , wherein the component (A) contains a polyisobutylene having an aromatic hydrocarbon group in its molecule.

5 . The photocurable composition according to claim 1 , wherein the component (C) contains a (meth)acrylate monomer having a structure of the following formula (C-1):

wherein R 1 represents a hydrogen or a methyl group, R 2 represents a hydrocarbon group having 1 to 20 carbon atoms, and n represents an integer of 0 to 10.

6 . The photocurable composition according to claim 1 , further comprising a filler as component (E), wherein the photocurable composition comprises 0.1 to 50 parts by mass of the component (E) relative to 100 parts by mass of the component (A).

7 . The photocurable composition according to claim 1 , wherein the component (B) is a urethane-modified (meth)acrylate oligomer not containing a rubber skeleton.

8 . A sealing agent comprising the photocurable composition according to claim 1 .

9 . A hard disk drive comprising the sealing agent according to claim 8 .

10 . A cured product obtained by curing the photocurable composition according to claim 1 by light irradiation.

11 . The photocurable composition according to claim 1 , wherein the component (C) contains isononyl (meth)acrylate.

12 . The photocurable composition according to claim 1 , wherein the component (B) has a weight average molecular weight in a range from more than 1,000 to 200,000 or less.

Assignees

• Three Bond Co Ltd

Inventors

• Matsui Chiaki

Classifications

• C08K3/36 Primary

  Silica · CPC title

• C09D151/003

  grafted on to macromolecular compounds obtained by reactions only involving unsaturated carbon-to-carbon bonds (C09D151/04, C09D151/06 take precedence) · CPC title

• C09D151/08

  grafted on to macromolecular compounds obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds · CPC title

• Y02P20/141

  Feedstock · CPC title

• C09K3/10

  {Materials in mouldable or extrudable form} for sealing or packing joints or covers (filling pastes C09D5/34) · CPC title