Hot melt adhesive composition for bonding WPP substrates

1. A hot melt adhesive composition comprising:

an amorphous poly-alpha-olefin terpolymer of propylene-ethylene-butene having a ring and ball softening point of from about 155° C. to about 165° C.,

an amorphous propylene/butene copolymer in an amount of from about 25% by weight to about 45% by weight based on the weight of the composition,

a grafted polyethylene, and

optionally, a wax.

2. The hot melt adhesive composition of claim 1 , wherein said adhesive has a glass transition temperature of no greater than about −25° C.

3. The hot melt adhesive composition of claim 1 , further comprising an antioxidant.

4. The hot melt adhesive composition of claim 1 , wherein said amorphous poly-alpha-olefin terpolymer has propylene content of no less than about 60%, based on the total terpolymer.

5. The hot melt adhesive composition of claim 1 , wherein said amorphous poly-alpha-olefin terpolymer has a ring and ball softening point of from about 157° C. to about 165° C.

6. The hot melt adhesive composition of claim 1 , wherein said-amorphous poly-alpha-olefin terpolymer is in an amount of from about 35% by weight to about 55% by weight, based on the weight of the composition.

7. The hot melt adhesive composition of claim 1 , wherein said grafted polyethylene is grafted with maleic acid, or maleic anhydride, or acrylic acid.

8. An article comprising:

a woven polypropylene substrate, and

a hot melt adhesive composition of claim 1 disposed on at least a portion of said substrate.

9. The article of claim 8 , further comprising a non-blocking agent disposed on top of said hot melt adhesive composition.

10. The article of claim 8 , wherein said substrate is an untreated woven polypropylene.

11. A woven polypropylene bag comprising the hot melt adhesive composition of claim 1 , a seam, a manufacturer end, and a customer end, said seam and said manufacturer end being sealed with said hot melt adhesive composition.

12. The bag of claim 11 , further comprising a hot melt adhesive composition of claim 1 disposed on said customer end.

13. The bag of claim 11 further comprising a layer of a non-blocking agent disposed on said hot melt adhesive composition.

14. The bag of claim 13 , wherein said non-blocking agent is maleated polypropylene.

15. The hot melt adhesive composition of claim 1 , wherein said substrates have a surface energy of no greater than about 30 dyne.

16. A method of making the article of claim 8 comprising applying said hot melt adhesive to at least a portion of said substrate at a temperature of from about 290° F. to about 350° F.

17. A method of manufacturing a bag, comprising:

applying an adhesive composition of claim 1 to one edge of a sheet or multiple sheets of a woven polypropylene substrate, and

bringing the opposite edge in contact with said adhesive to form a tube,

said tube including an adhesive sealed seam, a manufacturer end, and a customer end.

18. The method of claim 17 , further comprising applying said adhesive composition onto said manufacturer end, and sealing said manufacturer end.

19. The method of claim 17 , further comprising applying said adhesive composition onto said customer end.

20. The method of claim 19 , further comprising applying a non-blocking agent onto the surface of said adhesive composition.

21. The method of claim 20 , wherein said non-blocking agent is maleated polypropylene.

22. A hot melt adhesive composition comprising:

from about 25% by weight to about 45% by weight of an amorphous propylene/butene copolymer,

from about 35% by weight to about 55% by weight of an amorphous poly-alpha-olefin other than the amorphous propylene/butene copolymer,

a grafted polyethylene, and

from about 1% by weight to about 7% by weight of a wax.

23. The hot melt adhesive composition of claim 22 , wherein said amorphous poly-alpha-olefin is a terpolymer of propylene-ethylene-butene.