Compositions comprising cleavable crosslinker and methods

Patent metadata

Field	Value
Publication number	US-9732173-B2
Application number	US-201515119887-A
Country	US
Kind code	B2
Filing date	Apr 9, 2015
Priority date	Apr 24, 2014
Publication date	Aug 15, 2017
Grant date	Aug 15, 2017

Abstract

A composition is described comprising a polymer. The polymer comprises polymerized units derived from a cleavable crosslinking monomer. The cleavable crosslinking monomer comprises at least two free-radically polymerizable groups and at least one group having the formula —O—C(R 2 )(R 3 )—O—, wherein R 2 and R 3 are independently hydrogen, alkyl, or aryl. The composition has a Tg no greater than 50° C. In some embodiments, the composition has a storage modulus greater than 3×10 5 Pa at 25° C. and 1 Hz and may be characterized as a non-tacky polymer. In other embodiments, the composition is a pressure sensitive adhesive. Upon cleavage of at least a portion of the polymerized monomeric units derived from the cleavable crosslinking monomer, the composition exhibits a change in at least one physical property. In another embodiment, the composition comprises a polymer and fragments. The fragments comprise the reaction product of a free-radically polymerizable group bonded to a polymer chain and a pendent hydroxyl group. The composition has a Tg no greater than 50° C. Also described are articles, comprising the composition described herein (i.e. before and/or after cleavage); as well as methods of making the composition and methods of making articles.

First claim

What is claimed is:

1. A composition comprising
a polymer comprising polymerized units derived from
a cleavable crosslinking monomer, the cleavable crosslinking monomer comprising at least two free-radically polymerizable groups and at least one group having the formula —O—C(R 2 )(R 3 )—O—, wherein R 2 and R 3 are independently hydrogen, alkyl, or aryl; and
polymerized units derived from alkyl (meth)acrylate monomers having a Tg no greater than 10° C.;

and the composition has a Tg no greater than 50° C.

2. The composition of claim 1 wherein the polymer comprises polymerized units derived from one or more non-cyclic alkyl (meth)acrylate monomer(s) having 4 to 20 carbon atoms.

3. The composition of claim 1 wherein the composition has a storage modulus greater than 3×10 5 Pa at 25° C. and 1 Hz.

4. The composition of claim 1 wherein the composition is a pressure sensitive adhesive.

5. The composition of claim 4 wherein the composition has a wet out of less than 5 seconds/in 2 .

6. The composition of claim 1 wherein upon cleavage of at least a portion of the polymerized monomeric units derived from the cleavable crosslinking monomer, the composition exhibits a change in at least one physical property selected from
a) a decrease in polymer gel content of at least 10%;
b) a decrease in storage modulus of at least 10%; and
c) an increase in peel adhesion of at least 10%.

7. The composition of claim 1 wherein the polymer comprises at least 50 wt. % of polymerized units derived from one or more alkyl (meth)acrylate monomer(s) having 4 to 20 carbon atoms.

8. The composition of claim 1 wherein the composition comprises tackifer, plasticizer, or a combination thereof.

9. The composition of claim 1 wherein the composition comprises 0.1 to 20 wt. % of the cleavable crosslinking monomer.

10. The composition of claim 1 wherein the cleavable crosslinking monomer has the formula:

R 1 is hydrogen or methyl;
R 2 and R 3 are independently hydrogen, alkyl, or aryl; and
L 1 is a divalent linking group.

11. The composition of claim 1 wherein the cleavable crosslinking monomer has the formula:

R 1 is hydrogen or methyl;
R 3 is independently hydrogen, alkyl, or aryl; and
L 1 is a divalent linking group.

12. The composition of claim 1 wherein the polymer comprises polymerized units derived from octyl (meth)acrylate.

13. The composition of claim 1 wherein the polymer further comprises polymerized units derived from at least one monomer selected from acid-functional monomers, non-acid functional polar monomers, vinyl monomers, and combinations thereof.

14. The composition of claim 1 wherein the polymer further comprises a non-cleavable crosslinker.

15. The composition of claim 1 wherein the composition further comprises a photoacid generator or thermal acid generator.

16. An article comprising the composition of claim 1 on a substrate.

17. A method of making an article comprising providing a composition according to claim 1 disposed on a substrate;
exposing the composition to heat and/or radiation to cleave at least a portion of polymerized units derived from the cleavable crosslinking monomer.

18. A composition comprising
a polymer comprising polymerized units derived from
a cleavable crosslinking monomer, the cleavable crosslinking monomer comprising at least two free-radically polymerizable groups and at least one group having the formula —O—C(R 2 )(R 3 )—O—, wherein R 2 and R 3 are independently hydrogen, alkyl, or aryl; and at least 50 wt. % of polymerized units derived from one or more alkyl (meth)acrylate monomer(s) having 4 to 20 carbon atoms;

and the composition has a Tg no greater than 50° C.

19. The composition of claim 18 wherein the composition has a storage modulus greater than 3×10 5 Pa at 25° C. and 1 Hz.

20. The composition of claim 18 wherein the composition is a pressure sensitive adhesive.

21. The composition of claim 18 wherein upon cleavage of at least a portion of the polymerized monomeric units derived from the cleavable crosslinking monomer, the composition exhibits a change in at least one physical property selected from
a) a decrease in polymer gel content of at least 10%;
b) a decrease in storage modulus of at least 10%; and
c) an increase in peel adhesion of at least 10%.

22. The composition of claim 18 wherein the composition comprises tackifer, plasticizer, or a combination thereof.

23. The composition of claim 18 wherein the composition comprises 0.1 to 20 wt. % of the cleavable crosslinking monomer.

24. The composition of claim 18 wherein the cleavable crosslinking monomer has the formula:

R 1 is hydrogen or methyl;
R 2 and R 3 are independently hydrogen, alkyl, or aryl; and
L 1 is a divalent linking group.

25. The composition of claim 18 wherein the cleavable crosslinking monomer has the formula:

R 1 is hydrogen or methyl;
R 3 is independently hydrogen, alkyl, or aryl; and
L 1 is a divalent linking group.

26. The composition of claim 18 wherein the polymer comprises polymerized units derived from octyl (meth)acrylate.

27. The composition of claim 18 wherein the polymer further comprises polymerized units derived from at least one monomer selected from acid-functional monomers, non-acid functional polar monomers, vinyl monomers, and combinations thereof.

28. The composition of claim 18 wherein the polymer further comprises a non-cleavable crosslinker.

29. The composition of claim 18 wherein the composition further comprises a photoacid generator or thermal acid generator.

30. An article comprising the composition of claim 18 on a substrate.

31. A method of making an article comprising providing a composition according to claim 18 disposed on a substrate;
exposing the composition to heat and/or radiation to cleave at least a portion of polymerized units derived from the cleavable crosslinking monomer.

Assignees

• 3M Innovative Properties Co
• 3M Innovative Properties Co

Inventors

• Clapper Jason D
• Vogel Dennis E
• Fornof Ann Rhea-Helene
• Gaddam Babu N

Classifications

• C09J4/00 Primary

  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 title

• C09J7/385

  Acrylic polymers · CPC title

• C09J133/062

  Copolymers with monomers not covered by C09J133/06 · CPC title

• C08F220/26

  Esters containing oxygen in addition to the carboxy oxygen · CPC title

• C08F2810/10

  including a reactive processing step which leads, inter alia, to morphological and/or rheological modifications, e.g. visbreaking · CPC title