Removable pressure-sensitive adhesive strip

• US 10,435,594 B2
• Filed: 03/29/2016
• Issued: 10/08/2019
• Est. Priority Date: 04/02/2015
• Status: Active Grant

• Current Assignee: Tesa SE (maxingvest GmbH & Co. KGaA)
• Original Assignee: Tesa SE (maxingvest GmbH & Co. KGaA)
• Inventors: Blazejewski, Anna, Burmeister, Axel, Lohmann, Franciska, Petersen, Anika
• Primary Examiner(s): Ducheneaux, Frank D
• Application Number:
  US15/561,808
• Publication Number:
  US 20180112110A1
• Time in Patent Office: 1,288 Days
• Field of Search: None
• CPC Class Codes: B29B 7/426 with consecutive casings or screws, e.g. for charging, discharging, mixing
• CPC Class Codes: B29B 7/485 with three or more shafts provided with screws
• CPC Class Codes: B29B 7/487 with consecutive casings or screws, e.g. for feeding, discharging, mixing
• CPC Class Codes: B29B 7/845 Venting, degassing or removing evaporated components in devices with rotary stirrers
• CPC Class Codes: C08K 2201/005 Additives being defined by their particle size in general
• CPC Class Codes: C08K 5/01 Hydrocarbons C08K5/0091 takes precedence
• CPC Class Codes: C08K 7/22 Expanded, porous or hollow particles
• CPC Class Codes: C08L 2205/20 Hollow spheres
• CPC Class Codes: C09J 11/08 Macromolecular additives
• CPC Class Codes: C09J 153/02 Vinyl aromatic monomers and conjugated dienes
• CPC Class Codes: C09J 2203/318 for the production of liquid crystal displays
• CPC Class Codes: C09J 2203/322 for the production of solar panels
• CPC Class Codes: C09J 2203/326 for bonding electronic components such as wafers, chips or semiconductors
• CPC Class Codes: C09J 2301/122 the adhesive layer being present only on one side of the carrier, e.g. single-sided adhesive tape
• CPC Class Codes: C09J 2301/124 the adhesive layer being present on both sides of the carrier, e.g. double-sided adhesive tape
• CPC Class Codes: C09J 2301/30 characterized by the chemical, physicochemical or physical properties of the adhesive or the carrier
• CPC Class Codes: C09J 2301/302 the adhesive being pressure-sensitive, i.e. tacky at temperatures inferior to 30°C
• CPC Class Codes: C09J 2301/308 the adhesive tape or sheet losing adhesive strength when being stretched, e.g. stretch adhesive
• CPC Class Codes: C09J 2301/312 parameters being the characterizing feature
• CPC Class Codes: C09J 2301/408 additives as essential feature of the adhesive layer
• CPC Class Codes: C09J 2301/412 : presence of microspheres
• CPC Class Codes: C09J 2301/414 : presence of a copolymer
• CPC Class Codes: C09J 2425/00 : Presence of styrenic polymer
• CPC Class Codes: C09J 2453/00 : Presence of block copolymer
• CPC Class Codes: C09J 5/08 : using foamed adhesives
• CPC Class Codes: C09J 7/10 : without carriers
• CPC Class Codes: C09J 7/20 : characterised by their carriers
• CPC Class Codes: C09J 7/387 : Block-copolymers

Abstract

The invention relates to a pressure-sensitive adhesive strip, for the residue-free and nondestructive removal by which by substantially expanding it in the plane of adhesion, comprising an adhesive compound layer, said adhesive compound layer consisting of a pressure-sensitive adhesive compound, constituted by vinyl aromatic block copolymers and 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., preferably greater than 0° C., and a softening point (ring & ball) of greater than or equal to 70° C., preferably greater than or equal to 100° C., and the pressure-sensitive adhesive compound being foamed.

Claims

1. A pressure-sensitive adhesive strip that is redetachable without residue or destruction by extensive stretching substantially within the bond plane, the pressure-sensitive adhesive strip comprising a layer of adhesive consisting of a pressure-sensitive adhesive having a composition comprising one or more vinylaromatic block copolymers at 20% to 75% by weight of the total composition, one or more tackifying resins at 24.6% to 60% by weight of the total composition, and microballoons at 0.2% to 10% by weight of the total composition, wherein at least 75% by weight (based on the total resin content) of the one or more tackifying resins is at least one 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, wherein the foamed pressure-sensitive adhesive comprises a surface having a surface roughness R_a of less than 15 μ

m and the surface roughness R_a constitutes an average height of the roughness along the surface of the foamed pressure-sensitive adhesive.

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

3. The pressure-sensitive adhesive strip according to claim 2, wherein the vinylaromatics for construction of the A blocks comprise styrene, polystyrene, α

-methyl styrene and/or other styrene derivatives.

4. The pressure-sensitive adhesive strip according to 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 said monomers.

5. The pressure-sensitive adhesive strip according to 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)_nX or (A-B-A)_nX structure, in which:

the A blocks are independently a first polymer formed by polymerization of at least one vinylaromatic;

the B blocks are independently a second 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 second polymer;

X is the radical of a coupling reagent or initiator; and

n is an integer ≥

2.

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

7. The pressure-sensitive adhesive strip according to claim 1, wherein the pressure-sensitive adhesive consists of the following composition:

8. The pressure-sensitive adhesive strip according to claim 1, wherein an absolute density of the foamed pressure-sensitive adhesive is 350 to 990 kg/m³, and/or a relative density is 0.35 to 0.99, wherein the relative density is a ratio of a density of the foamed pressure-sensitive adhesive to a density of the unfoamed pressure-sensitive adhesive.

9. The pressure-sensitive adhesive strip according to claim 1, wherein, when the pressure-sensitive adhesive has been applied to one or both sides of a carrier, an absolute density of the foamed pressure-sensitive adhesive is between 220 to 990 kg/m³, and/or a relative density is between 0.20 to 0.99, wherein the relative density is a ratio of a density of the foamed pressure-sensitive adhesive to a density of the unfoamed pressure-sensitive adhesive.

10. The pressure-sensitive adhesive strip according to claim 9, wherein the carrier is 10 to 200 μ

m thick.

11. The pressure-sensitive adhesive strip according to claim 9, wherein the carrier has an elongation at break of at least 100%, and optionally a resilience of more than 50%.

12. The pressure-sensitive adhesive strip according to claim 1, wherein the pressure-sensitive adhesive strip has a carrier to one side of which the pressure-sensitive adhesive is applied as a layer, or to both sides of which the pressure-sensitive adhesive is applied as a layer, and further wherein the carrier, optionally, has a thickness of between 20 and 60 μ

m, and the layer of the pressure-sensitive adhesive, optionally, has a thickness of between 20 and 60 μ

m.

13. The pressure-sensitive adhesive strip according to claim 1, wherein the pressure-sensitive adhesive strip is of single-layer implementation, with the thickness of the pressure-sensitive adhesive strip being from 20 μ

m to 2000 μ

m.

14. The pressure-sensitive adhesive strip according to claim 1, wherein the surface roughness Ra is less than 10 μ

m.

15. A method comprising:

bonding components with the pressure-sensitive adhesive strip according to claim 1.