Pressure sensitive adhesive comprising vinylpyrrolidone

• US 20030153642A1
• Filed: 12/23/2002
• Published: 08/14/2003
• Est. Priority Date: 01/22/2002
• Status: Active Grant

• Current Assignee: BASF AG (BASF SE)
• Original Assignee: BASF AG (BASF SE)
• Inventors: Schumacher, Karl-Heinz, Jung, Martin, Diehl, Heiko, Fink, Ralf
• Granted Patent: US 6,858,295 B2
• Time in Patent Office: Days
• US Class Current: 522/74
• CPC Class Codes: C08L 2666/10 Homopolymers or copolymers according to C08L39/00 - C08L49/00; Derivatives thereof
• CPC Class Codes: C08L 33/06 of esters containing only carbon, hydrogen and oxygen, which oxygen atoms are present only as part of the carboxyl radical
• CPC Class Codes: C08L 39/06 Homopolymers or copolymers of N-vinyl-pyrrolidones
• CPC Class Codes: C09J 133/06 of esters containing only carbon, hydrogen and oxygen, the oxygen atom being present only as part of the carboxyl radical
• CPC Class Codes: C09J 139/06 Homopolymers or copolymers of N-vinyl-pyrrolidones
• CPC Class Codes: C09J 2203/334 as a label
• CPC Class Codes: Y10T 428/28 Web or sheet containing structurally defined element or component and having an adhesive outermost layer
• CPC Class Codes: Y10T 428/2852 Adhesive compositions
• CPC Class Codes: Y10T 428/2878 including addition polymer from unsaturated monomer
• CPC Class Codes: Y10T 428/2887 including nitrogen containing polymer [e.g., polyacrylonitrile, polymethacrylonitrile, etc.]

Abstract

A pressure sensitive adhesive comprising a mixture of

a radiation-crosslinkable polymer A) composed of at least 40% by weight of C1 to C18 alkyl (meth)acrylates and

a polymer B) composed of at least 20% by weight of vinylpyrrolidone and of less than 40% by weight of C1 to C18 alkyl (meth)acrylates

or a pressure sensitive adhesive comprising

a radiation-crosslinkable polymer C) composed of at least 40% by weight of C1 to C18 alkyl (meth)acrylates and comprising vinylpyrrolidone as comonomer,

the fraction of the polymer B) in the mixture being less than 15% by weight, based on the sum of A)+B), and the amount of vinylpyrrolidone in the polymer C) being less than 15% by weight.

Claims

1. A pressure sensitive adhesive comprising a mixture of

a radiation-crosslinkable polymer A) composed of at least 40% by weight of C1 to C18 alkyl (meth)acrylates and

a polymer B) composed of at least 20% by weight of vinylpyrrolidone and of less than 40% by weight of C1 to C18 alkyl (meth)acrylates

or a pressure sensitive adhesive comprising

a radiation-crosslinkable polymer C) composed of at least 40% by weight of C1 to C18 alkyl (meth)acrylates and comprising vinylpyrrolidone as comonomer,

the fraction of the polymer B) in the mixture being less than 15% by weight, based on the sum of A)+B), and the amount of vinylpyrrolidone in the polymer C) being less than 15% by weight.

2. An adhesive as claimed in claim 1, wherein the polymers A) and C) are composed of at least 60% by weight of C1 to C18 alkyl (meth)acrylates.

3. An adhesive as claimed in claim 1, wherein the amount of polymer B) is at least 2% by weight, based on the sum of A)+B), or the polymer C) is composed of at least 2% by weight of vinylpyrrolidone.

4. An adhesive as claimed in claim 1, wherein the polymers A) and C) are prepared by emulsion polymerization and are present in the form of an aqueous dispersion.

5. An adhesive as claimed in claim 1, wherein the polymers A) and C) are prepared by solution polymerization in an organic solvent.

6. An adhesive as claimed in claim 1, wherein the polymers A), B) and C) have a Fikentscher K value of not more than 80 (in 1% strength solution, in tetrahydrofuran solvent, at 21°

C.).

7. An adhesive as claimed in claim 1, comprising a photoinitiator.

8. An adhesive as claimed in claim 7, wherein the photoinitiator was attached to the polymer A) or the polymer C).

9. An adhesive as claimed in claim 1, wherein the polymer B) is added to the aqueous dispersion of the polymer A).

10. An adhesive as claimed in claim 1, wherein the polymer B) is added to the organic solution of polymer A) and then the solvent is separated off.

11. An adhesive as claimed in claim 1, wherein the amount of water and organic solvents is less than 5 parts by weight per 100 parts by weight of the sum of A) and B) or per 100 parts by weight of C).

12. An adhesive as claimed in claim 1, which is a hotmelt adhesive.

13. The use of the adhesive of claim 1, for producing self-adhesive articles, especially labels and adhesive tapes.

14. A process for producing self-adhesive articles, which comprises drying an adhesive as claimed in claim 1 to substrates, e.g., labels, adhesive tapes or films, and subsequently effecting crosslinking by UV light.

15. A self-adhesive article obtainable by a process as claimed in claim 14.

16. A self-adhesive article coated with an adhesive as claimed in claim 1.