Pressure-sensitive adhesive and detachable strip formed from it

• US 8,128,781 B2
• Filed: 05/02/2008
• Issued: 03/06/2012
• Est. Priority Date: 05/04/2007
• Status: Expired due to Fees

• Current Assignee: Tesa SE (maxingvest GmbH & Co. KGaA)
• Original Assignee: Tesa SE (maxingvest GmbH & Co. KGaA)
• Inventors: Krawinkel, Thorsten, Putlitz, Bodo Zu
• Primary Examiner(s): Tucker, Philip
• Assistant Examiner(s): ORLANDO, MICHAEL N
• Application Number:
  US12/113,983
• Publication Number:
  US 20080271846A1
• Time in Patent Office: 1,404 Days
• Field of Search: 156325-327, 525/216, 525/241
• US Class Current: 156/325
• 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. A method of forming and releasing an adhesive bond, said method comprising adhering a pressure-sensitive adhesive strip to a substrate to form an adhesive bond, and thereafter releasing the adhesive bond by stretching the adhesive strip substantially in the plane of said adhesive bond, wherein the adhesive strip comprises a pressure-sensitive adhesive 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 a total weight of resin.

2. Method according to claim 1, wherein the vinylaromatic block copolymer is a styrene block copolymer.

3. Method 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. Method according to claim 1, wherein the block copolymer is at least partly hydrogenated.

5. Method 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. Method according to claim 1, wherein the pressure-sensitive adhesive is transparent.

7. Method according to claim 1, 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.

8. Method according to claim 1, 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.