Propylene copolymers for adhesive applications

• US 20100029829A9
• Filed: 09/29/2006
• Published: 02/04/2010
• Est. Priority Date: 10/15/2002
• Status: Active Grant

• Current Assignee: Chad E. Bernard, Charles L. Sims, David R. Johnsrud, Patrick Brant, Peijun Jiang
• Original Assignee: ExxonMobil Chemical Patents Inc. (Exxon Mobil Corporation)
• Inventors: Bernard, Chad E., Brant, Patrick, Sims, Charles L., Jiang, Peijun, Johnsrud, David R.
• Granted Patent: US 8,653,169 B2
• Time in Patent Office: Days
• US Class Current: 524/487
• 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 51/003 grafted on to macromolecular compounds obtained by reactions only involving unsaturated carbon-to-carbon bonds C08L51/04, C08L51/06 take precedence
• CPC Class Codes: C08L 91/06 Waxes
• CPC Class Codes: C09J 123/142 at least partially crystalline copolymers of propene with other olefins

Abstract

Disclosed herein are adhesives comprising a copolymer comprising at least 80 wt % of units derived from propylene and from about 1 to about 20 wt % of units derived from at least one C₆ to C₁₀ alpha-olefin. The copolymer has a molecular weight of less than 100,000 and a heat of fusion between about 10 and about 70 J/g. An adhesive containing the copolymer preferably exhibits at least 50% fiber tear at −18° C. and at least 50% fiber tear at +25° C. using Inland paper board as a substrate; a viscosity of less than 50,000 mPa sec at 190° C., a set time of less than 4 seconds and a toughness of at least 3.4 megajoule/m³.

Claims

1. An adhesive comprising a copolymer comprising at least 80 wt % of units derived from propylene and from about 1 to about 20 wt % of units derived from at least one C₆ to C₁₀ alpha-olefin, wherein the copolymer has a molecular weight of less than 100,000 and a heat of fusion between about 10 and about 70 J/g and wherein the adhesive has the following properties:

(a) at least 50% fiber tear at −

18°

C. using Inland paper board as a substrate;

(c) at least 50% fiber tear at 25°

C. using Inland paper board as a substrate;

(d) a viscosity of less than 50,000 mPa sec at 190°

C.;

(e) a set time of less than 4 seconds; and

(f) a toughness of at least 3.4 megajoule/m³.

2. The adhesive of claim 1 wherein the copolymer comprises about 2 wt % to about 15 wt % of units derived from said at least one C₆ to C₁₀ alpha-olefin.

3. The adhesive of claim 1 wherein the copolymer comprises about 5 wt % to about 15 wt % of units derived from said at least one C₆ to C₁₀ alpha-olefin.

4. The adhesive of claim 1 wherein the copolymer consists essentially of units derived from propylene and said at least one C₆ to C₁₀ alpha-olefin.

5. The adhesive of claim 1 wherein said alpha-olefin has 6 to 8 carbon atoms.

6. The adhesive of claim 1 wherein said alpha-olefin comprises hexene-1.

7. The adhesive of claim 1 wherein said copolymer has a weight averaged molecular weight of less than 80,000.

8. The adhesive of claim 1 wherein said copolymer has a weight averaged molecular weight of less than 50,000.

9. The adhesive of claim 1 wherein said copolymer has a weight averaged molecular weight of at least 10,000.

10. The adhesive of claim 1 wherein the ratio of the weight averaged molecular weight of the copolyner to the number averaged molecular weight of the copolyner is between about 4 and about 9.

11. The adhesive of claim 1 said copolymer has a heat of fusion between about 10 and about 60 J/g.

12. The adhesive of claim 1 said copolymer has a heat of fusion between about 20 and about 50 J/g.

13. The adhesive of claim 1 further comprising at least 80 wt % of said copolymer and up to 20 wt % of at least one additive selected from waxes and functionalized polyolefins.

14. The adhesive of claim 13 wherein said at least one additive comprises a functionalized polyolefin and said functionalized polyolefin comprises up to 15 wt % of the adhesive.

15. The adhesive of claim 14 wherein said functionalized polyolefin comprises from 1 to 10 wt % of the adhesive.

16. The adhesive of claim 14 wherein said functionalized polyolefin comprises maleated polypropylene.

17. The adhesive of claim 13 wherein said at least one additive comprises a wax and said wax comprises up to 10 wt % of the adhesive.

18. The adhesive of claim 17 wherein said wax comprises from 2 to 8 wt % of the adhesive.

19. The adhesive of claim 1 wherein said adhesive has a Shear Adhesion Fail Temperature (SAFT) of at least 100°

C.

20. The adhesive of claim 1 wherein said adhesive has a Shear Adhesion Fail Temperature (SAFT) of at least 110°

C.

21. The adhesive of claim 1 wherein said copolymer has a viscosity at 190°

C. of less than 25,000 mPa sec.

22. The adhesive of claim 1 wherein said copolymer has a viscosity at 190°

C. of greater than 10,000 mPa sec and the adhesive has a toughness of at least 14 megajoule/m³ and an elongation of at least 400%.

23. The adhesive of claim 1 wherein said copolymer has a viscosity at 190°

C. of less than 10,000 mPa sec.

24. The adhesive of claim 1 wherein said copolymer has a viscosity at 190°

C. in the range from 1000 to 10,000 mPa sec and the adhesive has a toughness of at least 7 megajoule/m³ and an elongation of at least 100%.

25. The adhesive of claim 1 wherein said adhesive has a viscosity at 190°

C. of less than 5,000 mPa sec.

26. The adhesive of claim 1 wherein said adhesive has a viscosity at 190°

C. of less than 1,000 mPa sec.

27. The adhesive of claim 1 wherein said adhesive has a set time of less than 3 seconds.

28. The adhesive of claim 1 wherein said adhesive has a set time of less than 2 seconds.

29. An adhesive comprising a copolymer comprising at least 80 wt % of units derived from propylene and from about 1 to about 20 wt % of units derived from at least one C₆ to C₁₀ alpha-olefin, wherein the copolymer has a molecular weight of less than 50,000 and a heat of fusion between about 10 and about 70 J/g and wherein the adhesive has a Dot T-Peel adhesion of 8 newton or more for adhesion between a fiber board and a fabric substrate at room temperature (25°

C.) and a Dot T-Peel adhesion of 8 newton or more for adhesion between two polyethylene terephthalate (PET) films at room temperature (25°

C.) and at 40°

C.