Method for producing optical member and use of UV-curable resin composition therefor

• US 9,182,527 B2
• Filed: 10/19/2012
• Issued: 11/10/2015
• Est. Priority Date: 10/21/2011
• Status: Expired due to Fees

• Current Assignee: Nippon Kayaku Company Limited
• Original Assignee: Nippon Kayaku Company Limited
• Inventors: Kobayashi, Daisuke, Motohashi, Hayato, Matsuo, Yuichiro
• Primary Examiner(s): Choi, Ling
• Assistant Examiner(s): WHITELEY, JESSICA
• Application Number:
  US14/353,121
• Publication Number:
  US 20140256842A1
• Time in Patent Office: 1,117 Days
• Field of Search: 522/174, 522/173, 522/1, 520/1
• US Class Current: 1/1
• CPC Class Codes: B32B 17/06 comprising glass as the main or only constituent of a layer, next to another layer of a specific material
• CPC Class Codes: B32B 2037/243 Coating
• CPC Class Codes: B32B 2038/0076 Curing, vulcanising, cross-linking
• CPC Class Codes: B32B 2307/40 having particular optical properties light or UV resistant B32B2307/71
• CPC Class Codes: B32B 2310/0831 using UV radiation
• CPC Class Codes: B32B 2457/20 Displays, e.g. liquid crystal displays, plasma displays
• CPC Class Codes: B32B 7/12 using interposed adhesives or interposed materials with bonding properties
• CPC Class Codes: C08F 290/067 Polyurethanes; Polyureas
• CPC Class Codes: C08G 18/48 Polyethers
• CPC Class Codes: C08G 18/4825 Polyethers containing two hydroxy groups C08G18/4833 - C08G18/5096 take precedence
• CPC Class Codes: C08G 18/755 and at least one isocyanate or isothiocyanate group linked to a secondary carbon atom of the cycloaliphatic ring, e.g. isophorone diisocyanate
• CPC Class Codes: C08G 18/8175 with esters of acrylic or alkylacrylic acid having only one group containing active hydrogen
• CPC Class Codes: C09D 175/16 having terminal carbon-to-carbon unsaturated bonds
• CPC Class Codes: C09J 175/16 having terminal carbon-to-carbon unsaturated bonds
• CPC Class Codes: C09J 4/06 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 C09J159/00 - C09J187/00
• CPC Class Codes: G02B 5/208 for use with infrared or ultraviolet radiation, e.g. for separating visible light from infrared and/or ultraviolet radiation
• CPC Class Codes: G02F 2202/28 Adhesive materials or arrangements
• CPC Class Codes: G06F 2203/04103 Manufacturing, i.e. details related to manufacturing processes specially suited for touch sensitive devices
• CPC Class Codes: G06F 3/041 Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means
• CPC Class Codes: G06F 3/0412 Digitisers structurally integrated in a display

Abstract

The present invention relates to a method for producing an optical member wherein an optical substrate having a light-blocking part on the surface is bonded to an optical substrate for bonding. The method for producing an optical member uses a UV-curable resin composition and comprises specific (Process 1) through (Process 3). The present invention also relates to the use of a UV-curable resin composition comprising a (meth)acrylate (A) and a photopolymerization initiator (B) for the production method, and a UV-curable resin composition. It is possible to produce a bonded optical member having good curability and adhesiveness, such as a touch panel or display unit having an optical substrate comprising a light-blocking part, with good productivity but with little damage to the optical substrate. It is thereby possible to obtain an optical member having a high degree of resin curing at the light-blocking part and high reliability.

Claims

1. A method of producing an optical member including at least a pair of optical substrates, in which both of a transparent optical substrate having a light shielding portion on a surface thereof and another optical substrate to be bonded to the transparent optical substrate having a light shielding portion on a surface thereof are bonded to each other through a procedure including the following Process 1 to Process 3 using an ultraviolet curable resin composition, the method comprising:

Process 1;

a process of forming a coating layer by coating the ultraviolet curable resin composition on at least either of bonding surfaces of the transparent optical substrate having a light shielding portion on a surface thereof and another optical substrate to be bonded to the transparent optical substrate, and then allowing the coating layer to have a light shielded region selectively cured and the other part uncured by selectively irradiating the light shielded region, to be described below, in the coating layer thus obtained with ultraviolet rays in the air or in the presence of a curing inhibitory gas, wherein a surface of the coating layer in the other part uncured and a surface of the coating layer in the light shielded region where stickiness is preserved are obtained as a bonding surface, in which the light shielded region described above means a part of coating layer where ultraviolet rays do not reach since the part is shielded from ultraviolet rays by a light shielding portion when the two optical substrates are bonded to each other and the coating layer is irradiated with ultraviolet rays through the transparent optical substrate having a light shielding portion on the surface thereof;

Process 2;

a process of bonding the two optical substrates to each other by interposing the coating layer obtained in Process 1 between the bonding surfaces of the two optical substrates; and

Process 3;

a process of curing the uncured coating layer, which is interposed between the two optical substrates, by irradiating a laminated body having at least a pair of optical substrates bonded to each other by Processes 1 and 2 with ultraviolet rays through the transparent optical substrate having a light shielding portion.

2. The method of producing an optical member according to claim 1, the method further comprising the following Process 4 after Process 3,

Process 4:

a process of applying pressure with respect to the optical substrates bonded to each other.

3. The method of producing an optical member according to claim 1, wherein the part, which is a part other than the light shielded region of the coating layer and is to remain as uncured, is masked with an ultraviolet shielding plate and irradiation with ultraviolet rays is performed when the light shielded region is cured in Process 1.

4. The method of producing an optical member according to claim 1, wherein an irradiation dose of ultraviolet rays in Process 1 is at least 200 mJ/cm².

5. The method of producing an optical member according to claim 1, wherein the ultraviolet curable resin composition is coated at least either a surface provided with a light shielding portion of the optical substrate having a light shielding portion on a surface thereof or a display surface of a display unit that is the optical substrate to be bonded to the optical substrate having a light shielding portion on a surface thereof, and the optical substrate having a light shielding portion on a surface thereof and the display unit are bonded to each other such that a surface of the side having a light shielding portion of the optical substrate having a light shielding portion on a surface thereof and the display surface of the display unit face each other by interposing a coating layer thus obtained in Process 1.

6. The method of producing an optical member according to claim 1, wherein the optical substrate having a light shielding portion on a surface thereof is at least one selected from the group consisting of a transparent glass substrate having a light shielding portion, a transparent resin substrate having a light shielding portion, a glass substrate having a light shielding portion and a transparent electrode formed thereon, and the optical substrate to be bonded to the optical substrate having a light shielding portion on a surface thereof is at least one selected from the group consisting of a liquid crystal display unit, a plasma display unit, and an organic EL display unit.

7. The method of producing an optical member according to claim 1, wherein the ultraviolet curable resin composition is an ultraviolet curable resin composition including (A) a (meth)acrylate and (B) a photopolymerization initiator.

8. The method of producing an optical member according to claim 7, wherein (A) the (meth)acrylate is at least one selected from the group consisting of a urethane (meth)acrylate, a (meth)acrylate having a polyisoprene backbone, and a (meth)acrylate monomer.

9. The method of producing an optical member according to claim 8, wherein both of (i) a urethane (meth)acrylate or a (meth)acrylate having a polyisoprene backbone and (ii) a (meth)acrylate monomer are included as (A) the (meth)acrylate.

10. The method of producing an optical member according to claim 8 or 9, wherein (A) the (meth)acrylate is a urethane (meth)acrylate having a polypropylene oxide structure or a (meth)acrylate monomer.

11. The method of producing an optical member according to claim 10, wherein the urethane (meth)acrylate is a urethane (meth)acrylate obtained by reacting polypropylene glycol, polyisocyanate, and a hydroxyl group-containing (meth)acrylate.

12. The method of producing an optical member according to claim 8 or 9, wherein a weight average molecular weight of the urethane (meth)acrylate is from 7000 to 25000, and a number average molecular weight of the (meth)acrylate having a polyisoprene backbone is from 15000 to 50000.

13. The method of producing an optical member according to claim 8 or 9, wherein the ultraviolet curable resin composition includes other components other than (A) the (meth)acrylate and (B) the photopolymerization initiator, and includes a urethane (meth)acrylate at from 20 to 80% by weight and a (meth)acrylate monomer at from 5 to 70% by weight with respect to the total amount of the ultraviolet curable resin composition as (A) the (meth)acrylate, and (B) the photopolymerization initiator at from 0.2 to 5% by weight with respect to the total amount of the ultraviolet curable resin composition, and the balance is other components.

14. An optical member obtained by the method of producing an optical member according to any one of claim 1, 3, or 8.

15. A touch panel obtained by the method of producing an optical member according to claim 1.

16. A display device, which is obtained by the method of producing an optical member according to claim 5 and has an optical substrate having a light shielding portion on a surface thereof on a display screen of a display unit.

17. Use of an ultraviolet curable resin composition including (A) a (meth)acrylate and (B) a photopolymerization initiator for the method of producing an optical member according to any one of claims 1 to 5.

18. The use of an ultraviolet curable resin composition according to claim 17, wherein (A) the (meth)acrylate is at least one selected from the group consisting of a urethane (meth)acrylate, a (meth)acrylate having a polyisoprene backbone, and a (meth)acrylate monomer.

19. The use of an ultraviolet curable resin composition according to claim 17, wherein both of (i) a urethane (meth)acrylate or a (meth)acrylate having a polyisoprene backbone and (ii) a (meth)acrylate monomer are included as (A) the (meth)acrylate.

20. The use of an ultraviolet curable resin composition according to claim 18, wherein the urethane (meth)acrylate is a urethane (meth)acrylate obtained by reacting polypropylene glycol, polyisocyanate, and a hydroxyl group-containing (meth)acrylate.

21. An ultraviolet curable resin composition to be used in the method of producing an optical member according to claim 1, the composition comprising (A) a (meth)acrylate and (B) a photopolymerization initiator.

22. The ultraviolet curable resin composition according to claim 21, wherein (A) the (meth)acrylate is at least one selected from the group consisting of a urethane (meth)acrylate, a (meth)acrylate having a polyisoprene backbone, and a (meth)acrylate monomer.

23. The method of producing an optical member according to claim 7, wherein the ultraviolet curable resin composition is an ultraviolet curable resin composition further including a softening component.

24. The ultraviolet curable resin composition according to claim 21, the composition further comprising a softening component.

25. An optical member obtained by the method of producing an optical member according to claim 12.