Multi-arm block copolymer, and pressure sensitive adhesive and tape employing a multi-arm elastomeric block copolymer

• US 5,714,548 A
• Filed: 12/15/1995
• Issued: 02/03/1998
• Est. Priority Date: 05/25/1993
• Status: Expired due to Term

• Current Assignee: 3M Company
• Original Assignee: 3M Company
• Inventors: Nestegard, Mark Kevin, Ma, Jingjing
• Primary Examiner(s): ZEMEL, IRINA SOPJIA
• Application Number:
  US08/573,566
• Time in Patent Office: 781 Days
• Field of Search: 525/314, 525/316, 525/98
• US Class Current: 525/314
• CPC Class Codes: C08F 297/04 polymerising vinyl aromatic monomers and conjugated dienes
• CPC Class Codes: C08F 297/044 using a coupling agent
• CPC Class Codes: C08G 81/022 containing sequences of polymers of conjugated dienes and of polymers of alkenyl aromatic compounds
• CPC Class Codes: C08L 2666/02 Organic macromolecular compounds, natural resins, waxes or and bituminous materials
• CPC Class Codes: C08L 2666/28 Non-macromolecular organic substances
• CPC Class Codes: C08L 53/02 of vinyl-aromatic monomers and conjugated dienes
• CPC Class Codes: C09J 153/02 Vinyl aromatic monomers and conjugated dienes
• CPC Class Codes: C09J 2400/283 in the substrate
• CPC Class Codes: C09J 2453/00 Presence of block copolymer
• CPC Class Codes: C09J 7/10 without carriers
• CPC Class Codes: C09J 7/26 Porous or cellular plastics
• CPC Class Codes: C09J 7/381 based on macromolecular compounds obtained by reactions involving only carbon-to-carbon unsaturated bonds
• CPC Class Codes: C09J 7/387 Block-copolymers
• CPC Class Codes: Y10T 428/31797 Next to addition polymer from unsaturated monomers
• CPC Class Codes: Y10T 428/31895 Paper or wood
• CPC Class Codes: Y10T 428/31899 Addition polymer of hydrocarbon[s] only

Abstract

The present invention provides a novel multi-arm block copolymer, a novel pressure-sensitive adhesive made from a multi-arm elastomeric block copolymer, and a novel tape made therefrom. The multi-arm block copolymer has the general structure (A-B)_m Y(C-D)_n wherein A, B, C and D are polymer segments; Y is a residue of a multifunctional coupling agent; and m and n are the number of arms, where m and n are greater than 0 and the sum of m plus n is at least 3. A comprises a random copolymer of a monoalkenylarene and a conjugated diene; B and C comprise either a homopolymer of a conjugated diene or a polymer of two or more conjugated dienes; D comprises either a homopolymer of a monoalkenylarene or a copolymer of a monoalkenylarene and a conjugated diene wherein the Tg of D is greater than the Tg of A; and the weight percent of monoalkenylarene in the block copolymer is 40% or less. The pressure-sensitive adhesive of the invention comprises 100 parts by weight of either the previously described multi-arm block copolymer or a multi-arm block copolymer having the structure (A'"'"'-B)_m Y, about 20 to about 300 parts by weight of a tackifying resin, 0 to about 50 parts by weight of a crosslinking agent, and 0 to about 200 parts by weight of a plasticizer.

Claims

1. A pressure sensitive adhesive composition, comprising:

(a) 100 parts by weight of a multi-arm elastomeric block copolymer having the general structure (A'"'"'-B)_m Y wherein A'"'"' and B are polymer segments;

Y is a residue of a multifunctional coupling agent;

m is the number of arms and is at least three;

A comprises a random copolymer of a monoalkenylarene and a conjugated diene, wherein the Tg of A is less than 19°

C.; and

B comprises either a homopolymer of a conjugated diene or a polymer of two or more conjugated dienes;

(b) about 20 to about 300 parts by weight of a tackifying resin;

(c) 0 to about 50 parts by weight of a crosslinking agent; and

(d) 0 to about 200 parts of a plasticizer.

2. A pressure-sensitive adhesive according to claim 1, wherein A'"'"' comprises a copolymer of styrene and isoprene and B comprises a homopolymer of isoprene or butadiene or copolymer thereof.

3. A pressure-sensitive adhesive according to claim 1 wherein the adhesive composition is crosslinked.

4. A film of a pressure sensitive adhesive according to claim 1.

5. A tape comprising a pressure sensitive adhesive composition according to claim 1.

6. A tape according to claim 5 wherein said pressure-sensitive adhesive composition is crosslinked.

7. A tape according to claim 5 wherein said adhesive is provided as a layer on a carrier.

8. A tape according to claim 7 wherein said carrier comprises paper.

9. A tape according to claim 7 wherein said carrier comprises a polymeric material.

10. A tape according to claim 7 wherein said carrier comprises a release surface.

11. A tape according to claim 9 wherein said polymeric material is foamed.

12. A tape according to claim 5 wherein said adhesive composition is provided as a layer on opposite surfaces of the carrier.