Laminated structures
View Patent ↗Hot-melt, pressure-sensitive adhesive compositions of amorphous polyalphaolefin and crystalline polypropylene have improved bond strength over the amorphous polyalphaolefin alone. The adhesive compositions improve dynamic shear strength, dynamic peel strength, as well as static peel strength. The adhesive compositions are particularly suitable for use in absorbent articles.
1. A laminated structure comprising:
a first substrate;
a second substrate; and
a pressure sensitive hot melt adhesive bonding the first substrate and the second substrate to one another, wherein the adhesive includes an amorphous polyalphaolefin and a crystalline polypropylene having a degree of crystallinity of at least about 40%, the amorphous polyalphaolefin comprising a butene-1 terpolymer with ethylene and propylene and having a number-average molecular weight between about 5,000 and about 30,000 and a weight-average molecular weight between about 20,000 and about 60,000, the crystalline polypropylene having a number-average molecular weight between about 20,000 and about 300,000, and wherein the adhesive composition has a melt index between about 200 and about 2000 grams per 10 minutes.
2. The laminated structure of claim 1 , comprising between about 70% and about 90% of the amorphous polyalphaolefin, and between about 10% and about 30% of the crystalline polypropylene.
3. The laminated structure of claim 1 , comprising between about 73% and about 87% of the amorphous polyalphaolefin, and between about 13% and about 27% of the crystalline polypropylene.
4. The laminated structure of claim 1 , comprising between about 75% and about 85% of the amorphous polyalphaolefin, and between about 15% and about 25% of the crystalline polypropylene.
5. The laminated structure of claim 1 , wherein the degree of crystallinity of the crystalline polypropylene is at least about 60%.
6. The laminated structure of claim 1 , wherein the degree of crystallinity of the crystalline polypropylene is at least about 80%.
7. The laminated structure of claim 1 , wherein the amorphous polyalphaolefin has a weight-average molecular weight between about 25,000 and about 50,000.
8. The laminated structure of claim 1 , wherein the adhesive composition has a melt index between about 400 and about 1800 grams per 10 minutes.
9. The laminated structure of claim 1 , wherein the adhesive composition has a melt index between about 500 and about 1500 grams per 10 minutes.
10. The laminated structure of claim 1 , wherein the butene-1 terpolymer comprises betewen about 20% and about 65% by weight butene-1.
11. The laminated structure of claim 1 , wherein the butene-1 terpolymer comprises betewen about 30% and about 55% by weight butene-1.
12. The laminated structure of claim 1 , wherein the crystalline polypropylene comprises at least one of the group consisting of isotactic polypropylene, syndiotactic polypropylene, and combinations thereof.
13. The laminated structure of claim 1 , wherein the first and second substrates are each part of a single substrate.
14. The laminated structure of claim 1 , wherein each of the first and second substrates is selected from the group consisting of: nonwoven material, woven material, and film.
15. The laminated structure of claim 1 , wherein at least one of the first and second substrates comprises at least one of the group consisting of cellulosic material, thermoplastic material, and combinations thereof.
16. The laminated structure of claim 1 , wherein at least one of the first and second substrates comprises at least one of the group consisting of a necked-bonded laminate, a polypropylene spunbonded layer, and a polyethylene layer in combination with a polypropylene spunbonded layer.
17. The laminated structure of claim 1 , wherein the first and second substrates each comprise a neck-bonded laminate.
18. The laminated structure of claim 1 , wherein the first substrate comprises a film and the second substrate comprises a spunbond web.
19. The laminated structure of claim 1 , wherein the adhesive composition is melt-blown onto at least one of the first and second substrates.
20. The laminated structure of claim 1 , wherein the adhesive composition is applied to at least one of the first and second substrates in a swirl pattern.
21. The laminated structure of claim 1 , wherein the adhesive composition is applied to at least one of the first and second substrates in a concentration of between about 1 gram per square meter and about 50 grams per square meter.
22. The laminated structure of claim 1 , wherein the adhesive composition is applied to at least one of the first and second substrates in a concentration of between about 5 grams per square meter and about 20 grams per square meter.
23. The laminated structure of claim 1 , wherein the laminated structure has a dynamic shear bond strength greater than a dynamic shear material strength.
24. The laminated structure of claim 1 , wherein the laminated structure has a static peel bond strength greater than a static peel material strength.
25. A laminated structure comprising:
a first substrate;
a second substrate; and
a pressure sensitive hot melt adhesive bonding the first substrate and the second substrate to one another, wherein the adhesive includes an amorphous polyalphaolefin and a crystalline polypropylene having a degree of crystallinity of at least about 40%, the amorphous polyalphaolefin comprising a butene- 1 copolymer and having a number-average molecular weight between about 5,000 and about 30,000 and a weight-average molecular weight between about 20,000 and about 60,000, the crystalline polypropylene having a number-average molecular weight between about 10,000 and 100,000 and a weight-average molecular weight between about 20,000 and about 300,000, and wherein the adhesive composition has a melt index between about 200 and about 2000 grams per 10 minutes.
26. The laminated structure of claim 25 , comprising between about 70% and about 90% of the amorphous polyalphaolefin, and between about 10% and about 30% of the crystalline polypropylene.
27 .The laminated structure of claim 25 , comprising between about 73% and about 87% of the amorphous polyalphaolefin, and between about 13% and about 27% of the crystalline polypropylene.
28. The laminated structure of claim 25 , comprising between about 75% and about 85% of the amorphous polyalphaolefin, and between about 15% and about 25% of the crystalline polypropylene.
29. The laminated structure of claim 25 , wherein the degree of crystallinity of the crystalline polypropylene is at least about 60%.
30. The laminated structure of claim 25 , wherein the degree of crystallinity of the crystalline polypropylene is at least about 80%.
31. The laminated structure of claim 25 , wherein the amorphous polyalphaolefin has a weight-average molecular weight between about 25,000 and about 50,000.
32. The laminated structure of claim 25 , wherein the adhesive composition has a melt index between about 400 and about 1800 grams per 10 minutes.
33. The laminated structure of claim 25 , wherein the adhesive composition has a melt index between about 500 and about 1500 grams per 10 minutes.
34. The laminated structure of claim 25 , wherein the butene-1 copolymer comprises between about 25% and about 65% by weight butene-1, and a balance of a comonomer selected from the group consisting of ethylene, propylene, and combinations thereof.
35. The laminated structure of claim 25 , wherein the butene-1 copolymer comprises between about 30% and about 55% by weight butene-1, and a balance of a comonomer selected from the weight butene-1, and a balance of a comonomer selected from the group consisting of ethylene, propylene, and combinations thereof.
36. The laminated structure of claim 25 , wherein the crystalline polypropylene comprises at least one of the group consisting of isotactic polypropylenem syndiotactic polypropylene, and combinations thereof.
37. The laminated structure of claim 25 , wherein the first and second substrates are each part of a single substrate.
38. The laminated structure of claim 25 , wherein each of the first and second substrates is selected from the group consisting of: nonwoven material, woven material, and film.
39. The laminated structure of claim 25 , wherein at least one of the first and second substrated comprises at least one of the group consisting of cellulosic material, thermoplastic material, and combinations thereof.
40. The laminated structure of claim 25 , wherein at least one of the first and second substrates comprises at least one of the group consisting of a necked-bonded laminate, a polypropylene spunbonded layer, and a polyethylene layer in combination with a polypropylene spunbonded layer.
41. The laminated structure of claim 25 , wherein the first and second substrates each comprise a neck-bonded laminate.
42. The laminated structure of claim 25 , wherein the first substrate comprises a film and the second substrate comprises a spunbond web.
43. The laminated structure of claim 25 , wherein the adhesive composition is melt-blown onto at least one of the first and second substrates.
44. The laminated structure of claim 25 , wherein the adhesive composition is applied to at least one of the first and second substrates in a swirl pattern.
45. The laminated structure of claim 25 , wherein the adhesive composition is applied to at least one of the first and second substrates in a concentration of between about 1 gram per square meter and about 50 grams per square meter.
46. The laminated structure of claim 25 , wherein the adhesive composition is applied to at least one of the first and second substrates in a concentration of between about 5 grams per square meter and about 20 grams per square meter.
47. The laminated structure of claim 25 , wherein the laminated structure has a dynamic shear bond strength greater than a dynamic shear material strength.
48. The laminated structure of claim 25 , wherein the laminated structure has a static peel bond strength greater than a static peel material strength.