Pressure-sensitive adhesive strip

• US 20180163092A1
• Filed: 08/11/2017
• Published: 06/14/2018
• Est. Priority Date: 12/09/2016
• 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
• Granted Patent: US 10,669,455 B2
• Time in Patent Office: Days
• 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 7/526 with two or more rollers
• CPC Class Codes: B29B 7/748 Plants B29B7/7433, B29B7/7485, B29B7/7495 take precedence
• CPC Class Codes: B29B 7/823 Temperature control
• CPC Class Codes: B29B 7/826 Apparatus therefor
• CPC Class Codes: B29B 7/845 Venting, degassing or removing evaporated components in devices with rotary stirrers
• CPC Class Codes: B29B 7/90 Fillers or reinforcements , e.g. fibres
• CPC Class Codes: C08K 9/10 Encapsulated ingredients
• CPC Class Codes: C09J 11/08 Macromolecular additives
• CPC Class Codes: C09J 153/02 Vinyl aromatic monomers and conjugated dienes
• CPC Class Codes: C09J 2203/326 for bonding electronic components such as wafers, chips or semiconductors
• CPC Class Codes: C09J 2203/33 for batteries or fuel cells
• CPC Class Codes: C09J 2203/334 as a label
• 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 2301/302 the adhesive being pressure-sensitive, i.e. tacky at temperatures inferior to 30°C
• 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 2400/24 Presence of a foam
• CPC Class Codes: C09J 2453/00 : Presence of block copolymer
• CPC Class Codes: C09J 2467/006 : in the substrate
• CPC Class Codes: C09J 2475/006 : in the substrate
• CPC Class Codes: C09J 7/22 : Plastics; Metallised plastics
• CPC Class Codes: C09J 7/255 : Polyesters
• CPC Class Codes: C09J 7/38 : Pressure-sensitive adhesives [PSA]
• CPC Class Codes: C09J 7/387 : Block-copolymers

Abstract

The invention relates to a pressure-sensitive adhesive strip composed of at least three layers, comprising

• • an inner layer F composed of a non-extensible film carrier,
  • a layer SK1 composed of a self-adhesive composition arranged on one of the surfaces of the film carrier layer F and based on a vinylaromatic block copolymer composition foamed with microballoons,
  • a layer SK2 composed of a self-adhesive composition arranged on the opposite surface of the film carrier layer F from the layer SK1 and based on a vinylaromatic block copolymer composition foamed with microballoons, where the mean diameter of the voids formed by the microballoons in the self-adhesive composition layers SK1 and SK2 is independently 20 to 60 μm.

Claims

1. A pressure-sensitive adhesive strip comprising three layers as follows:

an inner layer F composed of a non-extensible film carrier,

a layer SK1 composed of a self-adhesive composition arranged on a surface of layer F and based on a vinylaromatic block copolymer composition foamed with microballoons,

a layer SK2 composed of a self-adhesive composition arranged on an opposite surface of layer F from layer SK1 and based on a vinylaromatic block copolymer composition foamed with microballoons,

where a mean diameter of each of voids formed by the microballoons in layers SK1 and SK2 is independently 20 to 60 μ

m.

2. The pressure-sensitive adhesive strip as claimed in claim 1, having a symmetric construction with respect to layer composition, in that the foamed vinylaromatic block copolymer compositions of layers SK1 and SK2 are chemically identical.

3. The pressure-sensitive adhesive strip as claimed in claim 1, having a structurally symmetric construction, in that layers SK1 and SK2 are of the same thickness and/or have the same density.

4. The pressure-sensitive adhesive strip as claimed in claim 1, wherein

the self-adhesive composition layers SK1 and/or SK2 are based on vinylaromatic block copolymers comprising polymer blocks (i) predominantly formed from vinylaromatics (A blocks), and (ii) predominantly formed by polymerization of 1,3-dienes (B blocks).

5. The pressure-sensitive adhesive strip as claimed in claim 1, wherein

the vinylaromatic block copolymer is 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

A blocks are independently a polymer formed by polymerization of at least one vinylaromatic,

B blocks are independently a polymer formed by polymerization of conjugated dienes having 4 to 18 carbon atoms, or a partly hydrogenated derivative of such a polymer,

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

n is an integer ≥

2.

6. The pressure-sensitive adhesive strip as claimed in claim 4, wherein

the vinylaromatics for formation of the A block include styrene, a-methylstyrene and/or styrene derivatives.

7. The pressure-sensitive adhesive strip as claimed in claim 4, wherein

monomer for forming the B block is selected from the group consisting of butadiene, isoprene, ethylbutadiene, phenylbutadiene, piperylene, pentadiene, hexadiene, ethylhexadiene, dimethylbutadiene, and a mixture thereof.

8. The pressure-sensitive adhesive strip as claimed in claim 1, wherein

proportion of the vinylaromatic block copolymers, based on overall self-adhesive composition layer SK1 or SK2, totals at least 20% by weight, and at most 75% by weight.

9. The pressure-sensitive adhesive strip as claimed in claim 1, wherein

layers SK1 and/or SK2 are formed on basis of vinylaromatic block copolymer and tackifying resin.

10. The pressure-sensitive adhesive strip as claimed in claim 9, wherein

layer SK1 and/or SK2 includes 20% to 60% by weight of tackifying resin, based on the total weight of the self-adhesive composition layer.

11. The pressure-sensitive adhesive strip as claimed in claim 9, wherein the tackifying resin, to an extent of at least 75% by weight, is hydrocarbon resin or terpene resin or a mixture thereof.

12. The pressure-sensitive adhesive strip as claimed in claim 1, wherein

proportion of the microballoons in layer SK1 and/or layer SK2 is up to 12% by weight, based in each case on overall composition of layer SK1 or layer SK2.

13. The pressure-sensitive adhesive strip as claimed in claim 1, wherein

mean diameter of the voids formed by the microballoons in layers SK1 and/or SK2, is 20 to 50 μ

m.

14. The pressure-sensitive adhesive strip as claimed in claim 1, wherein

layer SK1 and/or SK2 consists of the following composition:

15. The pressure-sensitive adhesive strip as claimed in claim 1, wherein

layer SK1 and/or SK2 consists of the following composition:

16. The pressure-sensitive adhesive strip as claimed in claim 1, wherein

layer SK1 and/or SK2 consists of the following composition:

17. The pressure-sensitive adhesive strip as claimed in claim 1, wherein

layer SK1 and/or SK2 have an absolute density of 400 to 990 kg/m³, and/or a relative density of 0.35 to 0.99.

18. The pressure-sensitive adhesive strip as claimed in claim 1, wherein

layer SK1 and/or SK2 have a thickness between 20 and 200 μ

m.

19. The pressure-sensitive adhesive strip as claimed in claim 1, wherein

one or both surfaces of layer F have been physically and/or chemically pretreated.

20. The pressure-sensitive adhesive strip as claimed in claim 19, wherein

the pretreatment is an etching operation and/or a corona treatment and/or a primer treatment.

21. The pressure-sensitive adhesive strip as claimed in claim 1, wherein

materials used for layer F are polyesters.

22. The pressure-sensitive adhesive strip as claimed in claim 1, wherein

layer F has a thickness between 5 and 125 μ

m.

23. The pressure-sensitive adhesive strip as claimed in claim 1, wherein

layer F has an elongation at break of less than 300%.

24. The pressure-sensitive adhesive strip as claimed in claim 1, wherein

layer F has a tensile strength in longitudinal direction of greater than 100 N/mm², and/or a tensile strength in transverse direction of greater than 100 N/mm².

25. The pressure-sensitive adhesive strip as claimed in claim 1,

having a thickness of 45 μ

m to 4000 μ

m.

26. A method of bonding components of accumulators or electronic devices, comprising application of a pressure-sensitive adhesive strip according to claim 1 to a substrate.