Polyolefin-based hot melt adhesives with improved processing and bonding performance

Patent metadata

Field	Value
Publication number	US-10759978-B2
Application number	US-201514882242-A
Country	US
Kind code	B2
Filing date	Oct 13, 2015
Priority date	Oct 13, 2014
Publication date	Sep 1, 2020
Grant date	Sep 1, 2020

Abstract

A hot melt adhesive made from a blend of a polypropylene-based polymer, a polyolefin elastomer, and an amorphous polyolefin. These adhesives exhibit excellent molten and pre-set flow allowing them to wet out substrates yet develop properties needed to form and maintain strong bonds making them useful for hygiene, construction, and packaging applications.

First claim

What is claimed is:

1. A hot melt adhesive, comprising:
(a) about 1% to about 30% by weight of a polypropylene random copolymer having a melting point between about 130° C. to about 165° C. and a melt enthalpy of between about 50 Joules/gram and about 100 Joules/gram;
(b) 22% to about 60% by weight of a polyolefin elastomer comprising a polypropylene homopolymer and having a melting point of less than about 130° C.;
(c) about 1% to about 40% by weight of an amorphous polyalphaolefin produced by a Ziegler-Natta catalyst;
(d) about 5% to about 70% by weight of a tackifying resin;
(e) 0% to about 60% by weight of a plasticizer;
(f) 0% to about 5% of a stabilizer or antioxidant;

wherein the viscosity of the composition is equal to or less than about 40,000 cP at 163° C. and the polypropylene random copolymer has a higher net crystallinity than the polyolefin elastomer.

2. The hot melt adhesive of claim 1 wherein the viscosity of the composition is equal to or less than 20,000 cP at 163° C.

3. The hot melt adhesive of claim 1 wherein the viscosity of the composition is equal to or less than 10,000 cP at 163° C.

4. The hot melt adhesive of claim 1 comprising about 2% to about 20% by weight of the polypropylene random copolymer.

5. The hot melt adhesive of claim 1 comprising 22% to about 50% by weight of the polyolefin elastomer.

6. The hot melt adhesive of claim 1 comprising 22% to about 40% by weight of the polyolefin elastomer.

7. The hot melt adhesive of claim 1 comprising about 2% to about 20% by weight of the amorphous polyalphaolefin.

8. The hot melt adhesive of claim 1 comprising about 10% to about 60% by weight of the tackifying resin.

9. The hot melt adhesive of claim 1 comprising about 20% to about 55% by weight of the tackifying resin.

10. The hot melt adhesive of claim 1 comprising about 1% to about 60% by weight of the plasticizer.

11. The hot melt adhesive of claim 1 comprising about 5% to about 50% by weight of the plasticizer.

12. The hot melt adhesive of claim 1 wherein said polypropylene random copolymer has a melt flow rate of about 0.5 grams/10 min to about 1000 grams/10 min.

13. The hot melt adhesive of claim 12 wherein said polyolefin elastomer comprises a metallocene catalyzed polypropylene homopolymer having a density of about 0.87 g/cc.

14. The hot melt adhesive of claim 1 wherein said amorphous polyalphaolefin comprises a copolymer of propylene with one or more alpha-olefin comonomer.

15. The hot melt adhesive of claim 14 wherein said alpha-olefin comonomer is ethylene, butene-1, hexene-1 or octene-1.

16. The hot melt adhesive of claim 1 further comprising an additional additive selected from the group consisting of ultraviolet light absorbers, surfactants, inert colorants, fluorescing agents, fillers, and mixtures thereof.

17. The hot melt adhesive of claim 1 , wherein the melting point of the polypropylene random copolymer is between about 142° C. to about 148° C.

18. The hot melt adhesive of claim 1 comprising from about 25% to about 60% by weight of the polyolefin elastomer.

19. The hot melt adhesive of claim 1 , wherein the polyolefin elastomer has a weight average molecular weight in the range of from about 75,000 g/mol to about 130,000 g/mol.

20. The hot melt adhesive of claim 1 , wherein the polyolefin elastomer has a Ring & Ball softening point of between about 100° C. to about 120° C.

21. The hot melt adhesive of claim 1 , wherein the polyolefin elastomer has a melt flow rate of about 50 grams/10 min to about 350 grams/10 min.

22. The hot melt adhesive of claim 1 , wherein the polyolefin elastomer has a viscosity of between about 50,000 cP to about 130,000 cP at 190° C.

23. The hot melt adhesive of claim 1 , wherein the polyolefin elastomer has a melt enthalpy of less than about 25 Joules/gram.

24. The hot melt adhesive of claim 1 , wherein the polyolefin elastomer has a melting point of less than about 80° C.

25. The hot melt adhesive of claim 1 , wherein said amorphous polyalphaolefin comprises a copolymer of propylene and butene-1.

26. A hot melt adhesive, comprising:
(a) about 8% to about 12% by weight of a polypropylene random copolymer having a melting point between about 130° C. to about 165° C. and a melt enthalpy of between about 50 Joules/gram and about 100 Joules/gram;
(b) 22% to about 28% by weight of a metallocene catalyzed polypropylene homopolymer elastomer having a density of about 0.87 g/cc and a melting point of less than about 130° C.;
(c) about 10% to about 15% by weight of an amorphous polyalphaolefin produced by a Ziegler-Natta catalyst;
(d) about 21% to about 27% by weight of a hydrocarbon tackifying resin;
(e) about 24% to about 29% by weight of a mineral oil plasticizer;
(f) 0% to about 5% of a stabilizer or antioxidant;

wherein the viscosity of the composition is equal to or less than about 10,000 cP at 163° C. and the polypropylene random copolymer has a higher net crystallinity than the polyolefin elastomer.

27. The hot melt adhesive of claim 26 wherein said polypropylene random copolymer has a melt flow rate of about 0.5 grams/10 min to about 1000 grams/10 min.

28. The hot melt adhesive of claim 26 wherein said amorphous polyalphaolefin comprises a copolymer of propylene with one or more alpha-olefin comonomer, said alpha-olefin comonomer comprising ethylene, butene-1, hexene-1 or octene-1.

29. The hot melt adhesive of claim 26 further comprising an additional additive selected from the group consisting of ultraviolet light absorbers, surfactants, inert colorants, fluorescing agents, fillers, and mixtures thereof.

30. The hot melt adhesive of claim 26 , wherein the melting point of the polypropylene random copolymer is between about 142° C. to about 148° C.

31. The hot melt adhesive of claim 26 , wherein said amorphous polyalphaolefin comprises a copolymer of propylene and butene-1.

Assignees

• Bostik Inc

Inventors

• Gray Steven Daniel
• Freund David Frederic
• Hamann Richard Edward
• Hu Miao
• Flores Fabrice Nicolas-Henri

Classifications

• C09J123/14

  Copolymers of propene (C09J123/16 takes precedence) · CPC title

• C08L2205/02

  containing two or more polymers of the same C08L -group · CPC title

• C09J123/142

  at least partially crystalline copolymers of propene with other olefins · CPC title

• C08L23/14

  Copolymers of propene (C08L23/16 takes precedence) · CPC title

• C08L23/12

  Polypropene · CPC title