TOUCH PANEL

• US 20140134434A1
• Filed: 01/17/2014
• Published: 05/15/2014
• Est. Priority Date: 07/19/2011
• Status: Active Grant

• Current Assignee: LG Chem Limited (LG Corporation)
• Original Assignee: LG Chem Limited (LG Corporation)
• Inventors: PARK, Min Soo, YANG, Se Woo, CHANG, Suk Ky, LEE, Seung Min
• Granted Patent: US 9,823,763 B2
• Time in Patent Office: Days
• US Class Current: 428/355.AC
• CPC Class Codes: C08F 220/10 Esters
• CPC Class Codes: C08K 5/37 Thiols
• CPC Class Codes: C08L 41/00 Compositions of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a bond to sulfur or by a heterocyclic ring containing sulfur; Compositions of derivatives of such polymers
• CPC Class Codes: C09J 133/08 Homopolymers or copolymers of acrylic acid esters
• CPC Class Codes: C09J 133/14 of esters containing halogen, nitrogen, sulfur or oxygen atoms in addition to the carboxy oxygen
• CPC Class Codes: C09J 4/00 Adhesives based on organic non-macromolecular compounds having at least one polymerisable carbon-to-carbon unsaturated bond ; adhesives, based on monomers of macromolecular compounds of groups C09J183/00 - C09J183/16
• CPC Class Codes: C09J 7/385 Acrylic polymers
• 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
• CPC Class Codes: Y10T 428/2891 including addition polymer from alpha-beta unsaturated carboxylic acid [e.g., acrylic acid, methacrylic acid, etc.] Or derivative thereof

Abstract

Provided is a touch panel. The touch panel includes a base and a pressure-sensitive adhesive layer attached to the base and having a peel strength with respect to a polycarbonate sheet of 1,900 g/25 mm or more. The pressure-sensitive adhesive layer includes an acryl polymer compound containing an acryl polymer and a thiol polymer derived by binding a thiol compound into a chain, or a side chain or terminal end of a chain of the acryl polymer. Accordingly, penetration of oxygen, moisture or other impurities at an interface between the base film and the pressure-sensitive adhesive layer, or at an interface between a conductor thin film and a pressure-sensitive adhesive layer may be effectively inhibited, and degradation in optical properties such as visibility due to bubbles generated at a pressure-sensitive adhesive interface may be prevented. In addition, when the pressure-sensitive adhesive layer is directly attached to the conductor thin film and even exposed to severe conditions such as high temperature or high temperature and high humidity, the change in the resistance of the conductor thin film may be effectively inhibited, and thus the touch panel may be stably driven for a long time.

Claims

1. A touch panel, comprising:

a base; and

a pressure-sensitive adhesive layer attached to the base, which comprises an acryl polymer compound containing an acryl polymer and a thiol polymer derived from an acryl monomer and a thiol compound, and

wherein the pressure-sensitive adhesive layer has a peel strength with respect to a polycarbonate sheet of 1,900 g/25 mm or more.

2. The touch panel according to claim 1, wherein the base further comprises a conductor thin film on at least one surface thereof, and the pressure-sensitive adhesive layer is directly attached to the conductor thin film.

3. The touch panel according to claim 1, wherein the acryl polymer compound has a weight average molecular weight of 200,000 to 2,500,000.

4. The touch panel according to claim 1, wherein the acryl polymer compound has a polydispersity index of 4.0 or more.

5. The touch panel according to claim 1, wherein the acryl polymer comprises a (meth)acrylic acid ester-based monomer in a polymerized form.

6. The touch panel according to claim 1, wherein the pressure-sensitive adhesive layer further comprises a multifunctional crosslinking agent crosslinking the acryl polymer compound.

7. The touch panel according to claim 1, wherein the pressure-sensitive adhesive layer has a resistance change ratio of an ITO electrode of 10% or less.

8. The touch panel according to claim 1, wherein the thiol compound is at least one of compounds represented by Formulas 1 to 4:

9. The touch panel according to claim 8, wherein R¹ is a linear or branched alkyl group having 3 to 20 carbon atoms.

10. A pressure-sensitive adhesive composition for a touch panel, comprising:

an acryl polymer compound containing an acryl polymer and a thiol polymer derived from an acryl monomer and a thiol compound,

wherein when a pressure-sensitive adhesive layer is formed by using the pressure-sensitive adhesive composition, the layer has a peel strength with respect to a polycarbonate sheet of 1,900 g/25 mm or more.

11. The composition according to claim 10, wherein the pressure-sensitive adhesive layer has a resistance change ratio of an ITO electrode of 10% or less.

12. The composition according to claim 10, which is applied to the pressure-sensitive adhesive layer of a touch panel comprising a base, and a pressure-sensitive adhesive layer attached to the base.

13. A double-sided pressure-sensitive adhesive tape for a touch panel, comprising a pressure-sensitive adhesive layer which is a cured product of the composition according to claim 10.

14. A method of preparing a pressure-sensitive adhesive composition for a touch panel, comprising:

initiating polymerization of a monomer mixture by inputting an initiator to the monomer mixture including an acryl monomer; and

adding a thiol compound after the polymerization reaction is initiated before the polymerization reaction is terminated.

15. The method according to claim 14, wherein the thiol compound is input between 1 minute after the initiation of the polymerization reaction and 15 minutes before the termination of the polymerization reaction.

16. The method according to claim 14, wherein the thiol compound is input between the time that the conversion rate of the monomer mixture is 5% and the time that the final conversion rate is 95%.

17. The method according to claim 14, wherein the thiol compound is added at 0.001 to 5 parts by weight with respect to 100 parts by weight of the monomer mixture.