Block copolymer hot-melt processable adhesives, methods of their preparation, and articles therefrom

• US 7,084,209 B2
• Filed: 05/04/2004
• Issued: 08/01/2006
• Est. Priority Date: 09/25/2000
• Status: Expired due to Term

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: D'Haese, Francois C., Everaerts, Albert I., Ma, JingJing
• Primary Examiner(s): Seidleck, James J.
• Assistant Examiner(s): Asinovsky, Olga
• Application Number:
  US10/838,312
• Publication Number:
  US 20040202881A1
• Time in Patent Office: 819 Days
• Field of Search: 525/98, 525/299, 525/308, 525/272
• US Class Current: 525/98
• CPC Class Codes: C08F 293/00 Macromolecular compounds obtained by polymerisation on to a macromolecule having groups capable of inducing the formation of new polymer chains bound exclusively at one or both ends of the starting macromolecule on to polymers modified by introduction of unsaturated end groups C08F290/02
• CPC Class Codes: C08F 293/005 using free radical "living" or "controlled" polymerisation, e.g. using a complexing agent
• CPC Class Codes: C08F 297/02 using a catalyst of the anionic type
• CPC Class Codes: C08F 297/026 polymerising acrylic acid, methacrylic acid or derivatives thereof
• CPC Class Codes: C08L 2666/02 Organic macromolecular compounds, natural resins, waxes or and bituminous materials
• CPC Class Codes: C08L 2666/24 Graft or block copolymers according to groups C08L51/00, C08L53/00 or C08L55/02; Derivatives thereof
• CPC Class Codes: C08L 53/00 Compositions of block copolymers containing at least one sequence of a polymer obtained by reactions only involving carbon-to-carbon unsaturated bonds; Compositions of derivatives of such polymers
• CPC Class Codes: C09D 153/00 Coating compositions based on block copolymers containing at least one sequence of a polymer obtained by reactions only involving carbon-to-carbon unsaturated bonds; Coating compositions based on derivatives of such polymers
• CPC Class Codes: C09J 153/00 Adhesives based on block copolymers containing at least one sequence of a polymer obtained by reactions only involving carbon-to-carbon unsaturated bonds; Adhesives based on derivatives of such polymers
• CPC Class Codes: C09J 2453/00 Presence of block copolymer
• CPC Class Codes: C09J 7/35 Heat-activated
• CPC Class Codes: C09J 7/387 Block-copolymers
• CPC Class Codes: Y10T 428/31855 Of addition polymer from unsaturated monomers

Abstract

Hot-melt processable adhesive, such as pressure-sensitive-adhesive (PSA) or heat-activatable adhesive, compositions of the present invention possess a broad formulation latitude and adequate cohesive strength after application for use in high performance applications. Hot-melt processable adhesives of the invention comprise at least one block copolymer comprising at least two A blocks and at least one B block. The A and B blocks are derived from monoethylenically unsaturated monomers, which monomers result in saturated polymer backbones without the need for subsequent hydrogenation upon their polymerization. Preferably, the block copolymer is a (meth)acrylate block copolymer.

Claims

1. A hot-melt processable adhesive composition comprising:

at least one block copolymer comprising at least two A blocks and at least one B block, wherein the A block is derived from at least one monoethylenically unsaturated monomer selected from the group consisting of (meth)acrylates, styrenes and vinyl esters, and wherein the B block is derived from at least one monoethylenically unsaturated monomer selected from the group consisting of (meth)acrylates, acrylamides and vinyl esters, wherein the boundaries between microdomains comprising the A blocks and a continuous phase comprising the B blocks are essentially free of tapered structures;

wherein the adhesive composition has a cohesive strength of at least about 2,000 minutes when measured according to ASTM D 3654.

9. The composition of claim 1, wherein the composition comprises an (A-B-A) triblock copolymer and an (A-B) diblock copolymer.

10. The composition of claim 1, wherein the block copolymer comprises at least one of:

(A-B-A) triblocks, -(A-B)_n- multiblocks, (A-B)_n- star blocks, and combinations thereof.

11. The composition of claim 1, wherein the block copolymer is a linear block copolymer.

2. A hot-melt processable adhesive composition comprising:

at least one block copolymer comprising at least two A blocks and at least one B block, wherein the A block is derived from at least one monomethylenically unsaturated monomer selected from the group consisting of (meth)acrylates, styrenes and vinyl esters, and wherein the B block is derived from at least one monoethylenically unsaturated monomer selected from the group consisting of (meth)acrylates, acrylamides and vinyl esters, and wherein the boundaries between microdomains comprising the A blocks and a continuous phase comprising the B blocks are essentially free of tapered structures;

wherein the block copolymer is polymerized via a living polymerization method.

3. A composition comprising:

at least one block copolymer comprising at least two A blocks and at least one B block, wherein the A block is derived from at least one monoethylenically unsaturated monomer selected from the group consisting of (meth)acrylates, styrenes and vinyl esters, and wherein the B block is derived from at least one monoethylenically unsaturated monomer selected from the group consisting of(meth)acrylates, acrylamides and vinyl esters, and wherein the boundaries between microdomains comprising the A blocks and a continuous phase comprising the B blocks are essentially free of tapered structures;

wherein the composition is a hot-melt processable adhesive and has a zero shear displacement when tested according to Shear Displacement test described herein.

4. A hot-melt processable adhesive composition comprising:

at least one block copolymer comprising at least two A blocks and at least one B block, wherein the A block is derived from at least one monoethylenically unsaturated monomer selected from the group consisting of (meth)acrylates, styrenes and vinyl esters, and wherein the B block is derived from at least one monoethylenically unsaturated monomer selected from the group consisting of (meth)acrylates, acrylamides and vinyl esters, and wherein the boundaries between microdomains comprising the A blocks and a continuous phase comprising the B blocks are essentially free of tapered structures, and the polydispersity of the block copolymer is about 1.5 or less.

5. The composition of claim 4, wherein polydispersity of the block copolymer is about 1.2 or less.

6. A hot-melt processable adhesive composition comprising:

at least one block copolymer comprising at least two A blocks and at least one B block, wherein the A block is derived from at least one monoethylenically unsaturated monomer selected from the group consisting of (meth)acrylates, styrenes and vinyl esters, and wherein the B block is derived from at least one monoethylenically unsaturated monomer selected from the group consisting of(meth)acrylates, acrylamides and vinyl esters, and wherein the A blocks are each essentially free of segments derived from a monomer used to prepare the B block and wherein the B block is essentially free of segments derived from a monomer used to prepare the A blocks and the boundaries between microdomains comprising the A blocks and a continuous phase comprising the B blocks are essentially free of tapered structures.

7. A hot-melt processable adhesive composition comprising:

at least one block copolymer comprising at least two A blocks and at least one B block, wherein the A block is derived from at last one monoethylenically unsaturated monomer selected from the group consisting of (meth)acrylates, styrenes and vinyl esters, and wherein the B block is derived from at least one monoethylenically unsaturated monomer selected from the group consisting of (meth)acrylates, acrylamides and vinyl esters, and wherein the block copolymer is essentially free of iniferter residue and the boundaries between microdomains comprising the A block and a continuous phase comprising the B blocks are essentially fee of tapered structures.

8. A hot-melt processable adhesive composition comprising:

at least one star block copolymer comprising A blocks and B blocks, wherein the A and B blocks are derived from monoethylenically unsaturated monomers, and wherein block copolymers in the composition consist essentially of the star block copolymer.

12. The composition of claim 8, wherein the A blocks are polymers independently derived from a monoethylenically unsaturated monomer, which as a homopolymer has a glass transition temperature (Tg) of greater than about 20°

C.

13. The composition of claim 12, wherein the monoethylenically unsaturated monomer is a (meth)acrylate monomer.

14. The composition of claim 8, wherein the B block is a polymer derived from a monoethylenically unsaturated monomer, which as a homopolymer has a glass transition temperature (Tg) of less than about 20°

C.

15. The composition of claim 8, wherein the B block is a polymer derived from a (meth)acrylate monomer.

16. The composition of claim 8, wherein the A blocks and B block are each independently derived from a monomer having a structure as follows: