PRESSURE-SENSITIVE ADHESIVE AND DETACHABLE STRIP FORMED FROM IT

• US 20080271846A1
• Filed: 05/02/2008
• Published: 11/06/2008
• Est. Priority Date: 05/04/2007
• Status: Active Grant

• Current Assignee: Tesa SE (maxingvest GmbH & Co. KGaA)
• Original Assignee: Tesa AG (maxingvest GmbH & Co. KGaA)
• Inventors: Krawinkel, Thorsten, Putlitz, Bodo Zu
• Granted Patent: US 8,128,781 B2
• Time in Patent Office: Days
• US Class Current: 156/327
• CPC Class Codes: C09J 153/02 Vinyl aromatic monomers and conjugated dienes
• 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 7/387 Block-copolymers

Abstract

Pressure-sensitive adhesive for single- or double-sidedly tacky pressure-sensitive adhesive strips redetachable without residue or destruction both by extensive stretching substantially in the bond plane and by peeling, the pressure-sensitive adhesive being composed at least of (1) a vinylaromatic block copolymer, (2) a solid tackifying resin having a softening temperature by the ring-and-ball method of more than 30° C. and (3) a resin which is liquid at room temperature (23° C.), the fraction of liquid resin accounting for at least 40% by weight, based on the total amount of resin. Strips formed from the adhesive and the use of the strips to form redetachable bonds are also disclosed.

Claims

1. Pressure-sensitive adhesive for single- or double-sidedly tacky pressure-sensitive adhesive strips redetachable without residue or destruction both by extensive stretching substantially in the bond plane and by peeling, the pressure-sensitive adhesive being composed at least of

a vinylaromatic block copolymer,

a solid tackifying resin having a softening temperature by the ring-and-ball method of more than 30°

C. and

a resin which is liquid at room temperature (23°

C.),

the fraction of liquid resin accounting for at least 40% by weight, based on the total amount of resin.

2. Pressure-sensitive adhesive according to claim 1, wherein the vinylaromatic block copolymer is a styrene block copolymer.

3. Pressure-sensitive adhesive according to claim 1, wherein the vinylaromatic block copolymer is composed of styrene as A block and, as B blocks, of butadiene and/or isoprene and/or their hydrogenation products or of isobutylene.

4. Pressure-sensitive adhesive according to claim 1, wherein the block copolymer is at least partly hydrogenated.

5. Pressure-sensitive adhesive according to claim 1, wherein the solid tackifying resin is selected from the group consisting of non-hydrogenated, partially hydrogenated or fully hydrogenated resins based on rosin or on rosin derivatives, hydrogenated polymers of dicyclopentadiene, non-hydrogenated, partially hydrogenated, selectively hydrogenated or fully hydrogenated hydrocarbon resins based on C₅, C₅/C₉ or C₉ monomer streams, polyterpene resins based on α

-pinene and/or β

-pinene and/or δ

-limonene, and/or a hydrogenated polymer of pure C₈- or C₉ aromatics.

6. Pressure-sensitive adhesive according to claim 1, which is transparent.

7. A pressure-sensitive adhesive strip comprising a pressure-sensitive adhesive according to claim 1.

8. A method of forming a redetachable adhesive bond comprising adhering a pressure-sensitive adhesive strip according to claim 7 to a substrate.

9. Method according to claim 8, wherein the pressure-sensitive adhesive strip has an extensible carrier and a layer of the pressure-sensitive adhesive applied on at least one side of said carrier.

10. Method according to claim 8, wherein the adhesive exhibits a tensile strength that is at least three times as great as a detachment force required when pulling on the pressure-sensitive adhesive strip in the direction of the bond plane.