Compositions with Improved Adhesion to Low Surface Energy Substrates

• US 20080113094A1
• Filed: 11/15/2006
• Published: 05/15/2008
• Est. Priority Date: 11/15/2006
• Status: Active Grant

• Current Assignee: Brady Worldwide Incorporated (Brady Corporation)
• Original Assignee: Brady Worldwide Incorporated (Brady Corporation)
• Inventors: Casper, Daniel J.
• Granted Patent: US 7,671,134 B2
• Time in Patent Office: Days
• US Class Current: 427/208.4
• CPC Class Codes: C08L 19/006 Rubber characterised by functional groups, e.g. telechelic diene polymers
• CPC Class Codes: C08L 2666/02 Organic macromolecular compounds, natural resins, waxes or and bituminous materials
• CPC Class Codes: C08L 33/04 Homopolymers or copolymers of esters C08L43/04 takes precedence
• CPC Class Codes: C09J 133/066 containing -OH groups

Abstract

Acrylic-based pressure sensitive adhesives are modified with a telechelic hydrocarbon oligomer. The oligomer comprises a hydrocarbon polymer chain or backbone and a functional end group, e.g., an oligomer prepared from a mono hydroxyl polybutadiene polymer and toluene diisocyanate. The oligomer attaches to the acrylic backbone of the polymer as a pendant group and in a preferred embodiment, the oligomer is mixed with the PSA shortly before the PSA is coated.

Claims

1. A pressure sensitive adhesive (PSA) composition comprising (i) a PSA with an acrylic-based polymer backbone, and (ii) an adhesion-promoting amount of a telechelic oligomer comprising a polymer backbone and a functional end group.

2. The composition of claim 1 in which the polymer backbone of the PSA comprises units derived from an alkyl methacrylate.

3. The composition of claim 2 in which the polymer backbone of the PSA comprises units derived from at least one of acrylic acid and a hydroxy-functional monomer.

4. The composition of claim 1 in which the polymer backbone of the oligomer comprises units derived from at least one of ethylene, C3-20 alpha-olefin and a diene.

5. The composition of claim 1 in which the polymer backbone of the oligomer comprises units derived from butadiene.

6. The composition of claim 5 in which the functional end group of the oligomer is derived from a diisocyanate.

7. The composition of claim 6 in which the functional end group is derived from toluene diisocyanate.

8. The composition of claim 1 in which the adhesion-promoting amount of the oligomer is between about 5 and about 25 weight percent based on the weight of the composition.

9. The composition of claim 1 in which the at least a portion of the oligomer is attached as a pendant group to the polymer backbone of the PSA.

10. The composition of claim 1 further comprising a tackifier.

11. The composition of claim 10 further comprising at east one of a plasticizer, anti-oxidant, pigment and UV-inhibitor.

15. A substrate in an adhering relationship with the PSA composition of claim 1.

16. The composition of claim 7 in which the polymer backbone of the oligomer is saturated.

17. The composition of claim 3 in which the hydroxy-functional monomer is hydroxy methyl methacrylate.

12. A method of applying a PSA to a substrate, the PSA comprising an acrylic-based polymer backbone, the method comprising the steps of (i) blending with the PSA an adhesion-promoting amount of a telechelic hydrocarbon oligomer to form a PSA composition, and (ii) applying the PSA composition to the substrate under conditions at which the oligomer attaches to the polymer backbone of PSA.

13. The method of claim 12 in which the PSA and oligomer are blended at about the time the PSA is applied to the substrate.

14. The method of claim 13 in which the composition is applied under ambient conditions.

18. The method of claim 14 in which the PSA composition is applied to the substrate by reverse roll, slot die, gravure or Meyer rod.