ULTRAVIOLET RADIATION CURABLE PRESSURE SENSITIVE ACRYLIC ADHESIVE

• US 20100255239A1
• Filed: 03/31/2010
• Published: 10/07/2010
• Est. Priority Date: 04/03/2009
• Status: Active Grant

• Current Assignee: Arkema France (Arkema)
• Original Assignee: Ashland Licensing and Intellectual Property Llc
• Inventors: Hammond, Terry E., Hu, Xiaochuan
• Granted Patent: US 8,735,506 B2
• Time in Patent Office: Days
• US Class Current: 428/41.500
• CPC Class Codes: B29C 2035/0827 using UV radiation
• CPC Class Codes: B29C 65/1406 Ultraviolet [UV] radiation
• CPC Class Codes: B29C 65/4815 Hot melt adhesives, e.g. thermoplastic adhesives
• CPC Class Codes: B29C 65/4825 Pressure sensitive adhesives
• CPC Class Codes: B29C 65/4845 Radiation curing adhesives, e.g. UV light curing adhesives
• CPC Class Codes: B29C 65/4865 containing additives C09J11/00 and subgroups take precedence
• CPC Class Codes: B29K 2023/06 PE, i.e. polyethylene
• CPC Class Codes: B29K 2023/065 HDPE, i.e. high density polyethylene
• CPC Class Codes: B29K 2023/12 PP, i.e. polypropylene
• CPC Class Codes: B32B 2037/1253 curable adhesive
• CPC Class Codes: B32B 2250/02 2 layers
• CPC Class Codes: B32B 2255/26 Polymeric coating
• CPC Class Codes: B32B 2310/0831 using UV radiation
• CPC Class Codes: B32B 2405/00 Adhesive articles, e.g. adhesive tapes labels B32B2519/00
• CPC Class Codes: B32B 37/1284 Application of adhesive
• CPC Class Codes: B32B 38/0008 Electrical discharge treatment, e.g. corona, plasma treatment; wave energy or particle radiation heat treatment B32B38/0036
• CPC Class Codes: B32B 7/12 using interposed adhesives or interposed materials with bonding properties
• CPC Class Codes: C08F 2/48 by ultraviolet or visible light
• CPC Class Codes: C08F 220/1808 C8-(meth)acrylate, e.g. isooctyl (meth)acrylate or 2-ethylhexyl (meth)acrylate
• CPC Class Codes: C08F 2800/20 as weight or mass percentages
• CPC Class Codes: C08F 2810/20 : leading to a crosslinking, either explicitly or inherently
• CPC Class Codes: C08F 8/00 : Chemical modification by after-treatment graft polymers, block polymers, crosslinking with unsaturated monomers or with polymers C08F251/00 - C08F299/00; of conjugated diene rubbers C08C
• CPC Class Codes: C08F 8/30 : Introducing nitrogen atoms or nitrogen-containing groups
• CPC Class Codes: C08G 18/62 : Polymers of compounds having carbon-to-carbon double bonds
• CPC Class Codes: C08G 18/6229 : Polymers of hydroxy groups containing esters of acrylic or methacrylic acid with aliphatic polyalcohols
• CPC Class Codes: C08G 18/6254 : Polymers of alpha-beta ethylenically unsaturated carboxylic acids and of esters of these acids containing hydroxy groups
• 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: C09J 133/066 : containing -OH groups
• 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 175/16 : having terminal carbon-to-carbon unsaturated bonds
• CPC Class Codes: C09J 2301/302 : the adhesive being pressure-sensitive, i.e. tacky at temperatures inferior to 30°C
• CPC Class Codes: C09J 2301/416 : use of irradiation
• CPC Class Codes: C09J 5/00 : Adhesive processes in general; Adhesive processes not provided for elsewhere, e.g. relating to primers
• CPC Class Codes: Y10T 428/1462 : Polymer derived from material having at least one acrylic or alkacrylic group or the nitrile or amide derivative thereof [e.g., acrylamide, acrylate ester, etc.]
• CPC Class Codes: Y10T 428/31551 : Of polyamidoester [polyurethane, polyisocyanate, polycarbamate, etc.]

Abstract

A process for making UV curable pressure sensitive adhesive compositions by derivatizing an acrylic polymer with a derivatizing agent prepared from a hydroxy-functional acrylate monomer and a diisocyanate. The derivatizing agent typically has a ratio of hydroxy-functional acrylate monomer to diisocyanate greater than about 1:1. Also disclosed are UV curable pressure sensitive adhesives made with the derivatizing agent and methods for adhering substrates with pressure sensitive adhesive compositions.

Claims

1. A process for making an ultraviolet (“

UV”

) curable pressure sensitive adhesive composition comprising the step of derivatizing an acrylic polymer with a derivatizing agent prepared from a hydroxy-functional acrylate monomer and a diisocyanate wherein the derivatizing agent has a ratio of hydroxy-functional acrylate monomer to diisocyanate greater than about 1;

1.

2. The process of claim 1 wherein the ratio is about 1.05:

1 to about 1.5;

1.

3. The process of claim 1 wherein the ratio is about 1.1:

1 to about 1.2;

1

4. The process of claim 1 wherein the acrylic polymer has a molecular weight of about 40,000 to about 100,000.

5. The process of claim 1 wherein the acrylic polymer comprises a monomer selected from the group consisting of 2-ethylhexyl acrylate, iso-octyl acrylate, iso-decyl acrylate, lauryl acrylate, n-butyl acrylate and combinations thereof.

6. The process of claim 1 wherein the acrylic polymer comprises a monomer selected from the group consisting of methyl acrylate, ethyl acrylate, methyl methacrylate, styrene, vinyl acetate and combinations thereof.

7. The process of claim 1 wherein the acrylic polymer comprises at least one backbone hydroxy-functional monomer.

8. The process of claim 7 wherein the backbone hydroxy-functional monomer is selected from the group consisting of 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, 4-hydroxybutyl acrylate and combinations thereof.

9. The process of claim 1 wherein the acrylic polymer comprises a functional monomer selected from the group consisting of acrylic acid, methacrylic acid, maleic anhydride, glycidyl methacrylate, N-vinyl pyrrolidone, N-vinyl caprolactam, acrylamide and combinations thereof.

10. The process of claim 1 wherein the diisocyanate is selected from the group consisting of isophorone diisocyanate, toluene diisocyanate and combinations thereof.

11. The process of claim 1 wherein the hydroxy-functional acrylate monomer is selected from the group consisting of 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 4-hydroxybutyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, caprolactone acrylate, hydroxyl acrylate and combinations thereof.

12. The process of claim 1 wherein the amount of derivatizing agent is about 2% to about 9% by weight solids.

13. A UV curable pressure sensitive adhesive composition made by the process of claim 1.

14. An ultraviolet (“

UV”

) curable pressure sensitive adhesive composition comprising a photoinitiator and an acrylic polymer reacted with a derivatizing agent prepared from hydroxy-functional acrylate monomer and diisocyanate, wherein derivatizing agent has a ratio of the hydroxy-functional acrylate monomer to diisocyanate greater than about 1;

1.

15. The UV curable pressure sensitive adhesive composition of claim 14 comprising a component selected from the group consisting of an inhibitor, a tackifier, a crosslinking agent, a stabilizer, a filler, a solvent, a plasticizer and combinations thereof.

16. The UV curable pressure sensitive adhesive composition of claim 14 wherein the ratio is about 1.05:

1 to about 1.5;

1.

17. The UV curable pressure sensitive adhesive composition of claim 14 wherein the ratio is about 1.1:

1 to about 1.2;

1

18. The UV curable pressure sensitive adhesive composition of claim 14 wherein the acrylic polymer has a molecular weight of about 40,000 to about 100,000.

19. The UV curable pressure sensitive adhesive composition of claim 14 wherein the acrylic polymer comprises a monomer selected from the group consisting of 2-ethylhexyl acrylate, iso-octyl acrylate, iso-decyl acrylate, lauryl acrylate, n-butyl acrylate and combinations thereof.

20. The UV curable pressure sensitive adhesive composition of claim 14 wherein the acrylic polymer comprises a monomer selected from the group consisting of methyl acrylate, ethyl acrylate, methyl methacrylate, styrene, vinyl acetate and combinations thereof.

21. The UV curable pressure sensitive adhesive composition of claim 14 wherein the acrylic polymer comprises at least one backbone hydroxy-functional monomer.

22. The UV curable pressure sensitive adhesive composition of claim 21 wherein the backbone hydroxy-functional monomer is selected from the group consisting of 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, 4-hydroxybutyl acrylate and combinations thereof.

23. The UV curable pressure sensitive adhesive composition of claim 14 wherein the acrylic polymer comprises a functional monomer selected from the group consisting of acrylic acid, methacrylic acid, maleic anhydride, glycidyl methacrylate, N-vinyl pyrrolidone, N-vinyl caprolactam, acrylamide and combinations thereof.

24. The UV curable pressure sensitive adhesive composition of claim 14 wherein the diisocyanate is selected from the group consisting of isophorone diisocyanate, toluene diisocyanate and combinations thereof.

25. The UV curable pressure sensitive adhesive composition of claim 14 wherein the hydroxy-functional acrylate monomer is selected from the group consisting of 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 4-hydroxybutyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, caprolactone acrylate, hydroxyl acrylate and combinations thereof.

26. The UV curable pressure sensitive adhesive composition of claim 14 wherein the amount of derivatizing agent is about 2% to about 9% by weight solids.

27. A method for the application of the UV curable pressure sensitive adhesive of claim 14 to one or more substrates comprising the steps of:

a. providing at least a first substrate and a second substrate each having one or more surfaces;

b. providing the pressure sensitive adhesive;

c. applying the pressure sensitive adhesive to a surface of the first substrate;

d. UV curing the pressure sensitive adhesive; and

e. mating the surface of the first substrate having the pressure adhesive with a surface of the second substrate to adhere the first substrate and the second substrate.

28. The method of claim 27 wherein the pressure sensitive adhesive is applied at a thickness greater than or equal to about 2 mils.

29. Two or more substrates adhered together by the method of claim 27.

30. A two sided transfer tape comprising a release liner wherein the release liner is coated with a material that comprises the pressure sensitive adhesive composition of claim 14 which has been cured.