Pressure-sensitive adhesive mass and the use thereof

• US 20040110882A1
• Filed: 01/06/2004
• Published: 06/10/2004
• Est. Priority Date: 11/10/2000
• Status: Active Grant

• Current Assignee: Tesa SE (maxingvest GmbH & Co. KGaA)
• Original Assignee: Tesa AG (maxingvest GmbH & Co. KGaA)
• Inventors: Krawinkel, Thorsten, Luhmann, Bernd, Franck, Kerstin
• Granted Patent: US 6,984,428 B2
• Time in Patent Office: Days
• US Class Current: 524/334
• CPC Class Codes: C09J 11/00 Features of adhesives not provided for in group C09J9/00, e.g. additives
• CPC Class Codes: C09J 11/06 organic
• CPC Class Codes: Y10T 428/1452 Polymer derived only from ethylenically unsaturated monomer
• CPC Class Codes: Y10T 428/2848 Three or more layers
• CPC Class Codes: Y10T 428/2861 having readily strippable combined with readily readhearable properties [e.g., stick-ons, etc.]
• CPC Class Codes: Y10T 428/2878 including addition polymer from unsaturated monomer
• CPC Class Codes: Y10T 428/2883 including addition polymer of diene monomer [e.g., SBR, SIS, etc.]

Abstract

The invention relates to a pressure-sensitive adhesive mass for adhesive tapes that can be released by stretching them in the plane of adhesion. The adhesive mass comprises a) a block copolymer of the styrene block copolymer type, b) adhesive resins, and c) antioxidants. The inventive mass is further characterized by a content in d) a sterically hindered mono- or polynuclear phenol that contains a benzylthioether group in the ortho and/or para position to the phenol OH group, and/or e) a sterically hindered phenol that carries a phenyl acrylate group in the ortho and/or the para position to the phenolic OH group, and/or f) a sterically hindered lactone.

Claims

1. A pressure sensitive adhesive for adhesive sheet strips redetachable by extensive stretching in the bond plane, comprising

a) block copolymer

b) tackifier resins, and

c) antioxidant

characterized by the presence therein of

d) sterically hindered monocyclic and/or polycyclic phenol containing a benzyl thioether group positioned ortho and/or para to the phenolic OH group, and/or

e) sterically hindered phenol which carries an acrylic acid phenyl ester group positioned ortho and/or para to the phenolic OH group, and/or

f) sterically hindered lactone.

2. The pressure sensitive adhesive of claim 1, characterized in that the monocyclic and/or polycyclic phenol d) is 4,4-bis(alkylthiomethyl)-o-cresol preferably 4,6-bis(octylthiomethyl)-o-cresol or 4,6-bis(dodecylthiomethyl)-o-cresol.

3. The pressure sensitive adhesive of claim 1, characterized in that the phenol e) is 2-tert-butyl-6-(3-tert-butyl-2-hydroxy-5-methylbenzyl)-4-methoxyphehyl acrylate or 2-[1-(2-hydroxy-3,5-di-tert-pentylphenyl)ethyl-4,6-di-tert-pentylphenyl acrylate.

4. The pressure sensitive adhesive of claim 1, characterized in that the lactone q is a substituted compound with the 3-phenyl-3H-benzofuran-2-one parent structure, in particular the reaction product of 3-hydroxy-5,7-di-tert-butyl-furan-2-one with oxylene.

5. The pressure sensitive adhesive of one of claims 1-4, characterized in that components d), e) and f) are present in total in an amount of 0.01 to 3.0 parts by weight based on 100 parts by weight of the overall pressure sensitive adhesive, in particular of 0.02 to 1.0.

6. The pressure sensitive adhesive of one of claims 1-5, characterized in that the block copolymer a) is present in an amount of 30 to 65, in particular from 35 to 60, the tackifier resin b) from 35 to 70, in particular from 40 to 65, and the antioxidant c) from 0 to 2.5, in particular from 0.05 to 1.5, all in parts by weight based on 100 parts by weight of the overall pressure sensitive adhesive.

7. The pressure sensitive adhesive of one of claims 1-6, characterized in that the block copolymer a) comprises polymer blocks formed from vinyl aromatics (A blocks), especially styrene, and those formed by polymerization of 1,3-dienes (D blocks), especially butadiene and/or isoprene and/or hydrogenation products thereof.

8. The pressure sensitive adhesive of one of claims 1-7, characterized in that the antioxidant c) is a primary and/or secondary antioxidant, in particular a sterically hindered phenol containing a 3-(p-hydroxyphenyl)propionic acid group or ac (3-(o-hydroxyphenyl)propionic acid group.

9. The pressure sensititive adhesive of one of claims 1-8, characterized in that it comprises further additives, especially light stabilizers, antiozonants, metal deactivators, processing assistants, endblock-reinforcing resins, plasticizing agents, fillers, color pigments, dyes and/or optical brighteners.

10. A single-sidedly or double-sidedly adhesive sheet strip redetachable by extensive stretching;

in the bond plane, comprising a pressure sensitive adhesive of one of claims 1-9.

11. The use of a pressure sensitive adhesive of one of claims 1-9 in a single-sidedly or double-sidedly adhesive sheet strip redetachable by extensive stretching in the bond plane.