Strippable systems based on acrylic block copolymers

• US 6,723,407 B2
• Filed: 02/13/2002
• Issued: 04/20/2004
• Est. Priority Date: 06/20/2001
• Status: Expired due to Term

• Current Assignee: Tesa SE (Maxingvest AG)
• Original Assignee: Tesa AG (Maxingvest AG)
• Inventors: Lühmann, Bernd, Dollase, Thilo, Husemann, Marc
• Primary Examiner(s): Ahmad, Nasser
• Application Number:
  US10/075,482
• Publication Number:
  US 20030096075A1
• Time in Patent Office: 797 Days
• Field of Search: 428/40.1, 428/41.3, 428/212, 428/214, 428/213, 428/355.R, 428/355.BL, 428/355.AC, 525/89, 525/94
• US Class Current: 428/40.1
• CPC Class Codes: C08F 293/005 using free radical "living" or "controlled" polymerisation, e.g. using a complexing agent
• CPC Class Codes: C08L 2666/24 Graft or block copolymers according to groups C08L51/00, C08L53/00 or C08L55/02; Derivatives thereof
• CPC Class Codes: C08L 53/00 Compositions of block copolymers containing at least one sequence of a polymer obtained by reactions only involving carbon-to-carbon unsaturated bonds; Compositions of derivatives of such polymers
• CPC Class Codes: C08L 53/02 of vinyl-aromatic monomers and conjugated dienes
• CPC Class Codes: C09J 153/00 Adhesives based on block copolymers containing at least one sequence of a polymer obtained by reactions only involving carbon-to-carbon unsaturated bonds; Adhesives based on derivatives of such polymers
• CPC Class Codes: C09J 153/02 Vinyl aromatic monomers and conjugated dienes
• CPC Class Codes: Y10T 428/14 Layer or component removable to expose adhesive
• CPC Class Codes: Y10T 428/1452 Polymer derived only from ethylenically unsaturated monomer
• CPC Class Codes: Y10T 428/24942 including components having same physical characteristic in differing degree
• CPC Class Codes: Y10T 428/2495 Thickness [relative or absolute]
• CPC Class Codes: Y10T 428/24959 of adhesive layers

Abstract

Strippable systems comprising at least one pressure sensitive adhesive based on at least one block copolymer, wherein said at least one block copolymer is based at least in part on (meth)acrylic acid derivatives, the block copolymers containing at least the unit P(A)-P(B)-P(A) composed of at least one polymer block P(B) and at least two polymer blocks P(A), where

P(A) independently of one another represent homopolymer or copolymer blocks of monomers A, the polymer blocks P(A) each having a softening temperature in the range from +20° C. to +175° C.,

P(B) represents a homopolymer or copolymer block of monomers B, the polymer block P(B) having a softening temperature in the range from −100° C. to +10° C., and

the polymer blocks P(A) and P(B) are not homogeneously miscible with one another.

Claims

1. A strippable system comprising at least one pressure sensitive adhesive based on at least one block copolymer, wherein said at least one block copolymer is based at least in part on (meth)acrylic acid derivatives, the block copolymers containing at least the unit P(A)-P(B)-P(A) composed of at least one polymer block P(B) and at least two polymer blocks P(A), where

P(A) independently of one another represent homopolymer or copolymer blocks of monomers A, the polymer blocks P(A) each having a softening temperature in the range from +20°

C. to +175°

C.,

P(B) representing a homopolymer or copolymer block of monomers B, the polymer block P(B) having a softening temperature in the range from −

100°

C. to +10°

C., and

the polymer blocks P(A) and P(B) are not homogeneously miscible with one another.

2. The strippable system as claimed in claim 1, wherein the pressure sensitive adhesive has an elongation at break of at least 300%, measured by test method B, and a tensile strength of at least 3 MPa, measured by test method B.

3. The strippable system according to claim 1, wherein the construction of the block copolymer (copolymers) can be described by one or more of the following general formulae:

4. The strippable system according to claim 1, wherein said at least one block copolymer has a symmetrical construction such that there are polymer blocks P(A) identical in chain length, chemical structure, or both;

polymer blocks P(B) identical in chain length, chemical structure, or both;

or any combination thereof.

5. The strippable system according to claim 1, wherein said at least one block copolymer meets one or more of the following criteria:

(a) a molar mass M_n of between 10 000 and 600 000 g/mol,

(b) a polydispersity D=M_w/M_n of not more than 3,

(c) a polymer block P(A) fraction of between 5 and 49% by weight, based on the triblock copolymer composition.

6. The strippable system according to claim 1, wherein the ratio of the chain lengths of the polymer blocks P(A) to those of the polymer blocks P(B) is chosen such that the polymer blocks P(A) are present in the form of a disperse phase (“

domains”

) in a continuous matrix of the polymer blocks P(B).

7. The strippable system according to claim 1, wherein the pressure sensitive adhesive comprises a blend of one or more block copolymers with at least one block copolymer which contains the inversely constructed unit P(B)-P(A)-P(B) or at least one diblock copolymer P(A)-P(B),

wherein the polymer blocks P(A) independently of one another represent homopolymer or copolymer blocks of monomers A, the polymer blocks P(A) each having a softening temperature in the range from +20°

C. to +175°

C.,

and wherein the polymer blocks P(B) independently of one another represent homopolymer or copolymer blocks of monomers B, the polymer blocks P(B) each having a softening temperature in the range from −

100°

C. to +10°

C., or at least one polymer P′

(A) or at least one polymer P′

(B),

wherein the polymers P′

(A) represent homopolymers copolymers of the monomers A, or both, the polymers P′

(A) each having a softening temperature in the range from +20°

C. to +175°

C.,

wherein the polymers P′

(B) represent homopolymers or copolymers of the monomers B, or both, the polymers P′

(B) each having a softening temperature in the range from −

100°

C. to +10°

C.,

and wherein the polymers P′

(A) or P′

(B) or both are optionally miscible with the polymer blocks P(A) and/or P(B), respectively

or any combination thereof.

8. The strippable system according to claim 1, wherein said at least one diblock copolymer meets one or more of the following criteria:

(a) a molar mass M_n of between 5 000 and 600 000 g/mol,

(b) a polydispersity D=M_w/M_n of not more than 3,

(c) a polymer block P(A) fraction of between 3 and 50% by weight, based on the diblock copolymer composition.

9. The strippable system according to claim 1, wherein the polymer blocks P(B) or the polymers P′

(B), or both contain, at least in part, one or more grafted-on side chains.

10. The strippable system according to claim 1, wherein monomers B comprise:

from 75 to 100% by weight of acrylic or methacrylic acid derivatives, or both, of the general structure (VI)

11. The strippable system according to claim 1, wherein the pressure sensitive adhesive is admixed with further components selected from the group consisting of tackifier resins plasticizers, fillers, nucleators, expandants, compounding agents, aging inhibitors and combinations thereof.

12. The strippable system according to claim 1, comprising a single-layer product construction in which the layer is composed of said at least one pressure sensitive adhesive and has a thickness of at least 100 μ

m.

13. The strippable system according to claim 1, comprising a multilayer product construction in which at least one of the layers is composed of said at least one pressure sensitive adhesive and has a thickness of at least 10 μ

m and in which optionally one of the further layers is composed of an elastomer and has a thickness of at least 100 μ

m.

14. The strippable system according to claim 1, comprising at least one backing or carrier layer.

15. The strippable system of claim 5, wherein said molar mass M_n is between 30,000 and 400,000 g/mol.

16. The strippable system of claim 15, wherein said molar mass M_n is between 50,000 and 300,000 g/mol.

17. The strippable system of claim 5, wherein said polymer block P(A) fraction is between 7.5 and 35% by weight.

18. The strippable system of claim 17, wherein said polymer block P(A) fraction is between 10 and 30% by weight.

19. The strippable system of claim 6, wherein said disperse phase is in the form of spherical or distortedly spherical domains.

20. The strippable system according to claim 8, wherein said molar mass M_n is between 15,000 and 400,000 g/mol.

21. The strippable system of claim 20, wherein said molar mass M_n is between 30,000 and 300,000 g/mol.

22. The strippable system according to claim 8, wherein said polymer block P(A) fraction is between 5 and 35% by weight.

23. The strippable system of claim 13, wherein said multilayer product construction is a two-layer or three-layer product construction.

24. The strippable system of claim 13, wherein said thickness of said at least one of the layers is at least 25 μ

m.

25. The strippable system of claim 13, wherein said one of the further layers has a thickness of at least 200 μ

m.