Pressure-sensitive adhesive strip for moisture-insensitive peelable adhesive bonds

• US 10,040,975 B2
• Filed: 01/28/2016
• Issued: 08/07/2018
• Est. Priority Date: 08/18/2006
• Status: Active Grant

• Current Assignee: Tesa SE (Maxingvest AG)
• Original Assignee: Tesa SE (Maxingvest AG)
• Inventors: Krawinkel, Thorsten, Junghans, Andreas
• Primary Examiner(s): DODDS, SCOTT
• Application Number:
  US15/009,003
• Publication Number:
  US 20160145471A1
• Time in Patent Office: 922 Days
• CPC Class Codes: B32B 43/006 Delaminating
• CPC Class Codes: B32B 5/04 characterised by a layer being specifically extensible by reason of its structure or arrangement , e.g. by reason of the chemical nature of the fibres or filaments
• CPC Class Codes: C09J 153/02 Vinyl aromatic monomers and conjugated dienes
• CPC Class Codes: C09J 183/04 Polysiloxanes
• CPC Class Codes: C09J 2301/1242 the opposite adhesive layers being different
• CPC Class Codes: C09J 2301/162 the carrier being a laminate constituted by plastic layers only
• CPC Class Codes: C09J 2301/302 the adhesive being pressure-sensitive, i.e. tacky at temperatures inferior to 30°C
• CPC Class Codes: C09J 2301/304 the adhesive being heat-activatable, i.e. not tacky at temperatures inferior to 30°C
• CPC Class Codes: C09J 2301/308 the adhesive tape or sheet losing adhesive strength when being stretched, e.g. stretch adhesive
• CPC Class Codes: C09J 2400/243 in the substrate
• CPC Class Codes: C09J 2423/105 in the release coating
• CPC Class Codes: C09J 2453/00 Presence of block copolymer
• CPC Class Codes: C09J 2467/006 in the substrate
• CPC Class Codes: C09J 2483/00 Presence of polysiloxane
• CPC Class Codes: C09J 7/26 Porous or cellular plastics
• CPC Class Codes: C09J 7/29 Laminated material metallised plastics C09J7/22
• CPC Class Codes: C09J 7/381 based on macromolecular compounds obtained by reactions involving only carbon-to-carbon unsaturated bonds
• CPC Class Codes: C09J 7/387 Block-copolymers
• CPC Class Codes: Y10T 156/1142 Changing dimension during delaminating [e.g., crushing, expanding, warping, etc.]
• CPC Class Codes: Y10T 428/249983 As outermost component
• CPC Class Codes: Y10T 428/2848 : Three or more layers

Abstract

A method of separating two substrates bonded with a redetachable, at least single-sidedly pressure-sensitive adhesive strip composed at least of a) a core layer which has a breaking extension of at least 300%, b) an outer carrier layer which has a breaking extension of not more than 120% and which at least sectionally is connected to the core layer such that it separates from the core layer when the latter is extensionally stretched, and c) a first adhesive layer which is applied at least sectionally to the side of the outer carrier layer that is opposite the side connected to the core layer, in which the core layer is stretched in the direction of the bond plane, starting from a region which has been made nonadhesive, until the core layer releases from at least one of the outer carrier layers so that the two substrates are separated from one another.

Claims

1. A method of separating two substrates bonded in a bond plane with a redetachable, pressure-sensitive adhesive strip, the adhesive strip bonded between the two substrates, comprising:

a) a core layer which has a breaking extension of at least 300%,

b) an outer carrier layer which has a breaking extension of not more than 120% and which is connected to the core layer such that it separates from the core layer when the core layer is extensionally stretched, and

c) a first adhesive layer which is applied to the side of the outer carrier layer that is opposite the side connected to the core layer;

the method comprising;

stretching the core layer in the bond plane, starting from a region which has been made nonadhesive, until the core layer releases from the outer carrier layer so that the two substrates are separated from one another and at least one of the two substrates remains bonded to the outer carrier layer via the first adhesive layer, and

peeling the outer carrier layer together with the first adhesive layer from the other substrate at an angle of removal of greater than 45°

.

2. The method of claim 1, wherein the core layer is formed from an adhesive which is redetachable by extensional stretching in the bond plane.

3. The method of claim 1, wherein the core layer protrudes beyond the outer carrier layer at least in one region.

4. The method of claim 3, wherein the protruding region is made nontacky by the application of pieces of film, foil or paper.

5. The method of claim 2, wherein the adhesive of the core layer is constructed on the basis of styrene block copolymers.

6. The method of claim 1, wherein a further adhesive layer is applied on the side of the core layer that is opposite the side connected to the outer carrier layer.

7. The method of claim 6, wherein between core layer and outer carrier layer there is a second adhesive layer which has the same composition as the further adhesive layer.

8. The method of claim 7, wherein the bond strengths of the second adhesive layer and of the further adhesive layer can be reduced by extensional stretching in the bond plane.

9. The method of claim 8, wherein the core layer protrudes beyond the outer carrier layer at least in one region.

10. The method of claim 8, wherein the core layer is comprised of at least one of:

a foam selected from the group consisting of low-density and very low-density polyethylenes (LDPE, LLDPE, VLDPE), ethylene-vinyl acetate copolymers and mixtures of aforementioned polymers;

or

films selected from the group consisting of polyvinyl acetates, polypropylenes, polyurethanes based on aromatic and aliphatic diisocyanates, polystyrene, impact-modified polystyrenes, PVC, and acrylate copolymers.

11. The method of claim 1, wherein the first adhesive layer is based on silicone and is crosslinked.

12. The method of claim 1, wherein on the core layer there is a second outer carrier layer which separates from the core layer when the core layer is extensionally stretched, and wherein the second outer carrier layer is optionally provided with a third adhesive layer on the free side thereof.

13. The method of claim 12, that wherein at least one of:

the outer carrier layer and the second outer carrier layer;

or the first and the third adhesive layers, are identical.

14. The method of claim 13, wherein at least one of:

the core layer, or the third adhesive, comprise block copolymers including at least one of;

polymer blocks formed from vinyl aromatics (A blocks);

or polymer blocks formed by polymerization of 1,3-dienes (B blocks).

15. The method of claim 14, wherein at least one of:

the vinyl aromatics are styrene;

or the B blocks are formed by polymerization of at least one of;

butadiene, isoprene, hydrogenation products of butadiene or isoprene, or isobutylene.