Ultraviolet cureable pressure sensitive adhesives comprising bound photoinitiator and vinyl groups

• US 9,546,305 B2
• Filed: 03/26/2014
• Issued: 01/17/2017
• Est. Priority Date: 03/29/2013
• Status: Active Grant

• Current Assignee: Arkema France (Arkema)
• Original Assignee: Ashland Licensing and Intellectual Property Llc
• Inventors: Hammond, Terry Emerson, Sun, Zhaohui
• Primary Examiner(s): Tran, Thao T
• Application Number:
  US14/225,902
• Publication Number:
  US 20140290856A1
• Time in Patent Office: 1,028 Days
• Field of Search: 428/355.EN, 524/272, 524/315, 524/365, 524/553, 524/558, 156/332, 427/553
• US Class Current: 1/1
• CPC Class Codes: C09J 133/066 containing -OH groups
• CPC Class Codes: C09J 133/08 Homopolymers or copolymers of acrylic acid esters
• CPC Class Codes: C09J 7/385 Acrylic polymers
• CPC Class Codes: Y10T 428/2878 including addition polymer from unsaturated monomer

Abstract

Pressure sensitive adhesive (“PSA”) compositions comprising a polymer having at least one vinyl group and a Type I photoinitiator bound to the polymer. The polymer is derivatized with a derivatizing agent comprising a vinyl group. The PSA can be cured by exposure to ultraviolet radiation.

Claims

1. A derivatized polymer, comprising a polymer backbone having constituents bound thereto, wherein (A) the polymer backbone is derived from at least one (meth)acrylate monomer, and (B) the constituents are:

(i) a photoinitiator adduct present in an amount ranging from about 1% to about 2%, by total weight of the photoinitiator adduct and the polymer backbone, wherein the photoinitiator adduct comprises a reaction product of (a) a Type I photoinitiator and (b) a (meth)acrylate monomer in the form of an anhydride or an acid; and

(ii) a derivatizing agent present in an amount ranging from about 1% to about 4%, by total weight of the derivatizing agent and the polymer backbone, comprising an acrylate monomer and a diisocyanate, wherein the molar ratio of the acrylate monomer to the diisocyanate is in a range of from about 1.05;

1 to about 1.5;

1 such that the derivatizing agent comprises a monoacrylate functionalized diisocyanate and a diacrylate functionalized diisocyanate.

2. The derivatized polymer of claim 1, wherein the at least one (meth)acrylate monomer is selected from the group consisting of 2-ethylhexyl acrylate, ethyl acrylate, isooctyl acrylate, iso-decyl acrylate, lauryl acrylate, n-butyl acrylate, acrylic acid, methyl acrylate, methyl methacrylate, butyl acrylate, vinyl acetate, methacrylic acid, β

-carboxyethyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 4-hydroxybutyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, and combinations thereof.

3. The derivatized polymer of claim 1, wherein the Type I photoinitiator is selected from the group consisting of benzoin, hydroxyacetophenone, and combinations thereof.

4. The derivatized polymer of claim 3, wherein the Type I photoinitiator is 2-hydroxy-1-[4-(2-hydroxyethoxy)phenyl]-2-methyl-1-propanone.

5. The derivatized polymer of claim 1, wherein the acrylate monomer of the derivatizing agent comprises a hydroxy-functional acrylate monomer.

6. The derivatized polymer of claim 5, 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, and combinations thereof.

7. The derivatized polymer of claim 1, wherein the diisocyanate is selected from the group consisting of isophorone diisocyanate, toluene diisocyanate, and combinations thereof.

15. A pressure sensitive adhesive composition comprising the derivatized polymer of claim 1.

16. The pressure sensitive adhesive composition of claim 15, further comprising an inhibitor selected from the group consisting of 4-methoxyphenol, hydroquinone, 2-methylhydroquinone, 2-t-butylhydroquinone, t-butyl catechol, butylated hydroxy toluene, butylated hydroxytoluene, butylated hydroxy anisole, phenothiazine, anaerobic inhibitors, and combinations thereof.

17. The pressure sensitive adhesive composition of claim 15, further comprising a crosslinking agent selected from the group consisting of ethoxylated hexanediol diacrylate, ethoxylated trimethylolpropane triacrylate, and combinations thereof.

18. The pressure sensitive adhesive composition of claim 15, further comprising a rosin ester.

19. The pressure sensitive adhesive composition of claim 15, further comprising a solvent selected from the group consisting of ethyl acetate, acetone, hexane, heptane, toluene, and combinations thereof.

20. A process, comprising:

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

b. providing the pressure sensitive adhesive of claim 15;

c. applying the pressure sensitive adhesive to at least one surface of the first substrate; and

d. curing the pressure sensitive adhesive with ultraviolet radiation.

21. The process of claim 20, further comprising providing a second substrate having one or more surfaces and mating the surface of the first substrate having the pressure sensitive adhesive with a surface of the second substrate.

22. A coated substrate made by the process of claim 20.

8. A process for making a derivatized polymer comprising a polymer backbone having constituents bound thereto, the process comprising:

a) reacting (i) a Type I photoinitiator and (ii) one or more (meth)acrylate monomers in the form of an anhydride or an acid to obtain a photoinitiator adduct, wherein the photoinitiator is present in an amount ranging from about 1% to about 2%, by total weight of the photoinitiator adduct and the polymer backbone

b) reacting the photoinitiator adduct and a polymer backbone comprising one or more monomers to obtain a polymer backbone having a bound photoinitiator adduct, and

c) reacting the polymer backbone having the bound photoinitiator adduct of step b) and a derivatizing agent comprising at least one vinyl group, wherein the derivatizing agent comprises an acrylate monomer and a diisocyanate at a molar ratio in a range of from about 1.05;

1 to about 1.5;

1 of the acrylate monomer to the diisocyanate such that the derivatizing agent comprises a monoacrylate functionalized diisocyanate and a diacrylate functionalized diisocyanate, and further wherein the derivatizing agent is present in an amount ranging from about 1% to about 4%, by total weight of the derivatizing agent and the polymer backbone.

9. The process of claim 8, wherein the acrylate monomer of the derivatizing agent comprises a hydroxy-functional acrylate monomer selected from the group consisting of 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 4-hydroxybutyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, caprolactone acrylate, and combinations thereof.

10. The process of claim 8, wherein the Type I photoinitiator is selected from the group consisting of benzil, benzoin ethers, benzil esters, hydroxyacetophenones, phosphine oxides, and combinations thereof.

11. The process of claim 8, wherein at least one of the one or more monomers in step b) comprises a hydroxyl group and step c) comprises reacting the derivatizing agent and the hydroxyl group.

12. The process of claim 11, wherein an acid group on the polymer comprises the hydroxyl group.

13. The process of claim 8, wherein the one or more monomers in step b) are selected from the group consisting of 2-ethylhexyl acrylate, ethyl acrylate, isooctyl acrylate, iso-decyl acrylate, lauryl acrylate, n-butyl acrylate, acrylic acid, methyl acrylate, methyl methacrylate, butyl acrylate, vinyl acetate, methacrylic acid, β

-carboxyethyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 4-hydroxybutyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, and combinations thereof.

14. A derivatized polymer, comprising a polymer backbone having constituents bound thereto, wherein (A) the polymer backbone is derived from at least one (meth)acrylate monomer, and (B) the constituents are:

(i) a photoinitiator adduct present in an amount ranging from about 1% to about 2%, by total weight of the photoinitiator adduct and the polymer backbone, wherein the photoinitiator adduct comprises a reaction product of (a) a Type I photoinitiator and (b) a (meth)acrylate monomer in the form of an anhydride; and

(ii) a derivatizing agent present in an amount ranging from about 1% to about 4%, by total weight of the derivatizing agent and the polymer backbone, comprising an acrylate monomer and a diisocyanate, wherein the molar ratio of the acrylate monomer to the diisocyanate is in a range of from about 1.05;

1 to about 1.5;

1 such that the derivatizing agent comprises a monoacrylate functionalized diisocyanate and a diacrylate functionalized diisocyanate.