Removable pressure-sensitive adhesive strip

Patent metadata

Field	Value
Publication number	US-10759974-B2
Application number	US-201916551109-A
Country	US
Kind code	B2
Filing date	Aug 26, 2019
Priority date	Apr 2, 2015
Publication date	Sep 1, 2020
Grant date	Sep 1, 2020

Abstract

Pressure-sensitive adhesive (PSA) strips, configured or adapted for the residue-free and non-destructive removal by which by substantially expanding it in the plane of adhesion, are provided. The PSA strips comprise at least one adhesive compound layer consisting of a PSA compound, constituted by vinyl aromatic block copolymers and one or more adhesive resins, at least 75 wt.-% (relative to the total amount of resin) of a resin being selected that has a DACP (diacetone alcohol cloud point) of greater than −20° C., and a softening point (ring & ball) of greater than or equal to 70° C., and the PSA compound has being foamed.

First claim

The invention claimed is:

1. A pressure-sensitive adhesive strip that is redetachable without residue or destruction by extensive stretching substantially within a bond plane, the pressure-sensitive adhesive strip comprising a layer of adhesive consisting of:
a pressure-sensitive adhesive constructed on the basis of one or more vinylaromatic block copolymers and one or more tackifying resins, with selection to an extent of at least 75% by weight, based on a total tackifying resin content, of at least one tackifying resin having a DACP (diacetone alcohol cloud point) of greater than −20° C. and a softening temperature (ring & ball) of not less than 70° C., and the pressure-sensitive adhesive having been foamed by means of microballoons, wherein the absolute density of the foamed pressure-sensitive adhesive is 350 to 990 kg/m 3 , and wherein the foamed pressure-sensitive adhesive comprises a surface having a surface roughness R a of less than 15 μm.

2. The pressure-sensitive adhesive strip of claim 1 , wherein the one or more vinylaromatic block copolymers comprise polymer blocks predominantly formed from vinylaromatics (A blocks) and polymer blocks predominantly formed by polymerization of 1,3-dienes (B blocks).

3. The pressure-sensitive adhesive strip of claim 2 , wherein the vinylaromatics for construction of the A block are ones selected from styrene, polystyrene, α-methylstyrene and/or other styrene derivatives.

4. The pressure-sensitive adhesive strip of claim 2 , wherein a monomer for the B blocks is selected from the group consisting of butadiene, isoprene, ethylbutadiene, phenylbutadiene, piperylene, pentadiene, hexadiene, ethylhexadiene, and dimethylbutadiene, and mixtures of the monomers.

5. The pressure-sensitive adhesive strip of claim 1 , wherein the one or more vinylaromatic block copolymers used are at least one synthetic rubber in the form of a block copolymer having an A-B, A-B-A, (A-B) n , (A-B) n X or (A-B-A) n X structure, in which:
the A blocks are independently a polymer formed by polymerization of at least one vinylaromatic;
the B blocks are independently a polymer formed by polymerization of conjugated dienes having 4 to 18 carbon atoms and/or isobutylene, or a partly or fully hydrogenated derivative of the polymer;
X is the radical of a coupling reagent or initiator; and
n is an integer≥2.

6. The pressure-sensitive adhesive strip of claim 5 , wherein the one or more block copolymer have an A-B structure and/or an A-B-A structure.

7. The pressure-sensitive adhesive strip of claim 1 , wherein a proportion of the one or more vinylaromatic block copolymers in total, based on the overall pressure-sensitive adhesive, is at least 20% by weight and at most 75% by weight.

8. The pressure-sensitive adhesive strip of claim 7 , wherein the proportion of the one or more vinylaromatic block copolymers in total, based on the overall pressure-sensitive adhesive, is at least 35% by weight and at most 55% by weight.

9. The pressure-sensitive adhesive strip of claim 1 , wherein the pressure-sensitive adhesive includes 20% to 60% by weight of the one or more tackifying resins, based on the total weight of the pressure-sensitive adhesive.

10. The pressure-sensitive adhesive strip of claim 9 , wherein the pressure-sensitive adhesive includes 30% to 50% by weight of the one or more tackifying resins, based on the total weight of the pressure-sensitive adhesive.

11. The pressure-sensitive adhesive strip of claim 1 , wherein the one or more tackifying resins comprises at least 75% by weight of hydrocarbon resins, terpene resins, or a mixture thereof.

12. The pressure-sensitive adhesive strip of claim 1 , wherein the absolute density of the foamed pressure-sensitive adhesive is 450 to 970 kg/m 3 .

13. The pressure-sensitive adhesive strip of claim 1 , wherein, if the pressure-sensitive adhesive has been applied to a carrier on one side of the carrier or two sides of the carrier, the absolute density of the foamed pressure-sensitive adhesive is between 500 to 990 kg/m 3 .

14. The pressure-sensitive adhesive strip of claim 1 , wherein the pressure-sensitive adhesive strip has a carrier to one side or two sides of which the pressure-sensitive adhesive is applied.

15. The pressure-sensitive adhesive strip of claim 14 , wherein the carrier has an elongation at break of at least 100% and a resilience of more than 50%.

16. The pressure-sensitive adhesive strip of claim 1 , wherein the pressure-sensitive adhesive strip is in the form of a diecut.

17. The pressure-sensitive adhesive strip of claim 1 , wherein the foamed pressure-sensitive adhesive comprises a surface having a surface roughness R a of less than 10 μm.

18. The pressure-sensitive adhesive strip of claim 1 , wherein a ratio of a tensile force to a stripping force of the pressure-sensitive adhesive strip is greater than two.

19. Bonded components comprising:
a first component;
a second component; and
the pressure-sensitive adhesive strip of claim 1 being double-sided and bonded to the first component and the second component,
wherein the first component comprises one or more electronic components and the second component comprises one or more electronic devices.

20. The bonded components of claim 19 , wherein the one or more electronic devices comprises at least one cellphone.

Assignees

• Tesa Se

Inventors

• Blazejewski Anna
• Burmeister Axel
• Lohmann Franciska
• Petersen Anika

Classifications

• B29B7/845

  Venting, degassing or removing evaporated components in devices with rotary stirrers · CPC title

• C09J7/00

  Adhesives in the form of films or foils · CPC title

• C09J2301/412

  presence of microspheres · CPC title

• C09J2301/408

  additives as essential feature of the adhesive layer · CPC title

• C09J2301/308

  the adhesive tape or sheet losing adhesive strength when being stretched, e.g. stretch adhesive · CPC title