Laminated absorbent product

Abstract

The present invention is generally directed to adhesive compositions comprising selected ratios of crystalline and amorphous polymers. In some versions of the invention, polymers capable of existing in different configurations (e.g., a polymer such as polypropylene which can exist in an atactic, syndiotactic. or isotactic configuration) are used to prepare adhesives of the present invention. As an example, a selected amount of isotactic polypropylene is blended with a selected amount of atactic polypropylene to prepare an adhesive composition having one or more performance properties (e.g., bond strength) that are superior to the performance properties of a conventional hot-melt adhesive. The adhesive compositions of the present invention are suitable for use in the preparation of laminated disposable absorbent products.

What is claimed is:  
     
         1 . An absorbent article comprising a laminated structure, the laminated structure comprising a first layer comprising polypropylene and a second layer comprising polypropylene, the first layer and second layer being attached to each other using an adhesive composition comprising an atactic polymer and an isotactic polymer, the atactic polymer having a degree of crystallinity of less than about 20% and a number-average molecular weight of from about 1,000 to about 300,000 and the isotactic polymer having a degree of crystallinity of at least about 40% and a number-average molecular weight of from about 3,000 to about 200,000.  
     
     
         2 . The absorbent article as set forth in  claim 1  wherein the degree of crystallinity of the atactic polymer is less than about 15%.  
     
     
         3 . The absorbent article as set forth in  claim 1  wherein the degree of crystallinity of the isotactic polymer is at least about 60%.  
     
     
         4 . The absorbent article as set forth in  claim 1  wherein the number-average molecular weight of the atactic polymer is between about 3,000 and about 100,000.  
     
     
         5 . The absorbent article as set forth in  claim 1  wherein the number-average molecular weight of the isotactic polymer is between about 10,000 and about 100,000.  
     
     
         6 . The absorbent article as set forth in  claim 1  wherein the adhesive composition is hot-melt processable at less than about 450 degrees Fahrenheit.  
     
     
         7 . The absorbent article as set forth in  claim 1  wherein the adhesive composition is hot-melt processable at less than about 350 degrees Fahrenheit.  
     
     
         8 . The absorbent article as set forth in  claim 1  wherein the adhesive composition has a melt index of from about 100 to about 2000 grams per 10 minutes.  
     
     
         9 . The absorbent article as set forth in  claim 1  wherein the adhesive composition comprises from about 50 to about 90 weight percent of the atactic polymer and from about 5 to about 50 weight percent of the isotactic polymer.  
     
     
         10 . The absorbent article as set forth in  claim 1  wherein the atactic polymer comprises atactic polypropylene.  
     
     
         11 . The absorbent article as set forth in  claim 1  wherein the atactic polymer is selected from the group consisting of low density polyethylene, ataxic polystyrene, ataxic polybutene, amorphous polyolefin copolymer, and combinations thereof.  
     
     
         12 . The absorbent article as set forth in  claim 11  wherein the low density polyethylene has a density in the range of 0.910 to 0.935 grams per cubic centimeter.  
     
     
         13 . The absorbent article as set forth in  claim 1  wherein the isotactic polymer comprises isotactic polypropylene.  
     
     
         14 . The absorbent article as set forth in  claim 1  wherein the isotactic polymer is selected from the group consisting of high density poylethylene, isotactic polystyrene, isotactic polybutene, and combinations thereof.  
     
     
         15 . The absorbent article as set forth in  claim 1  wherein the high density polyethylene has a density in the range of 0.935 to 0.980 grams per cubic centimeter.  
     
     
         16 . The absorbent article as set forth in  claim 1  wherein the first layer comprises a spunbond polypropylene layer.  
     
     
         17 . The absorbent article as set forth in  claim 16  wherein the second layer comprises a spunbond polypropylene layer.  
     
     
         18 . The absorbent article as set forth in  claim 16  wherein the second layer comprises a polypropylene film.  
     
     
         19 . The laminated structure as set forth in  claim 1  wherein the laminated structure is an outer cover and the first layer comprises a spunbond polypropylene layer and the second layer comprises a polypropylene film.  
     
     
         20 . An absorbent article comprising a laminated structure, the laminated structure comprising a first layer comprising polypropylene and a second layer comprising polyethylene, the first layer and second layer being attached to each other using an adhesive composition comprising an atactic polymer and an isotactic polymer, the atactic polymer having a degree of crystallinity of less than about 20% and a number-average molecular weight of from about 1,000 to about 300,000 and the isotactic polymer having a degree of crystallinity of at least about 40% and a number-average molecular weight of from about 3,000 to about 200,000.  
     
     
         21 . The absorbent article as set forth in  claim 20  wherein the degree of crystallinity of the atactic polymer is less than about 15%.  
     
     
         22 . The absorbent article as set forth in  claim 20  wherein the degree of crystallinity of the isotactic polymer is at least about 60%.  
     
     
         23 . The absorbent article as set forth in  claim 20  wherein the number-average molecular weight of the atactic polymer is between about 3,000 and about 100,000.  
     
     
         24 . The absorbent article as set forth in  claim 20  wherein the number-average molecular weight of the isotactic polymer is between about 10,000 and about 100,000.  
     
     
         25 . The absorbent article as set forth in  claim 20  wherein the adhesive composition is hot-melt processable at less than about 450 degrees Fahrenheit.  
     
     
         26 . The absorbent article as set forth in  claim 20  wherein the adhesive composition is hot-melt processable at less than about 350 degrees Fahrenheit.  
     
     
         27 . The absorbent article as set forth in  claim 20  wherein the adhesive composition has a melt index of from about 100 to about 2000 grams per 10 minutes.  
     
     
         28 . The absorbent article as set forth in  claim 20  wherein the adhesive composition comprises from about 50 to about 90 weight percent of the atactic polymer and from about 5 to about 50 weight percent of the isotactic polymer.  
     
     
         29 . The absorbent article as set forth in  claim 20  wherein the atactic polymer comprises atactic polypropylene.  
     
     
         30 . The absorbent article as set forth in  claim 20  wherein the atactic polymer is selected from the group consisting of low density polyethylene, ataxic polystyrene, ataxic polybutene, amorphous polyolefin copolymer, and combinations thereof.  
     
     
         31 . The absorbent article as set forth in  claim 30  wherein the low density polyethylene has a density in the range of 0.910 to 0.935 grams per cubic centimeter.  
     
     
         32 . The absorbent article as set forth in  claim 20  wherein the isotactic polymer comprises isotactic polypropylene.  
     
     
         33 . The absorbent article as set forth in  claim 20  wherein the isotactic polymer is selected from the group consisting of high density poylethylene, isotactic polystyrene, isotactic polybutene, and combinations thereof.  
     
     
         34 . The absorbent article as set forth in  claim 20  wherein the high density polyethylene has a density in the range of 0.935 to 0.980 grams per cubic centimeter.  
     
     
         35 . The absorbent article as set forth in  claim 20  wherein the first layer comprises a spunbond polypropylene layer and the second layer comprises a polyethylene film.  
     
     
         36 . The absorbent articles as set forth in  claim 20  wherein the laminated structure is a pub patch.  
     
     
         37 . An absorbent article comprising a laminated structure, the laminated structure comprising a first layer comprising polypropylene and a second layer comprising a cellulosic material, the first layer and second layer being attached to each other using an adhesive composition comprising an atactic polymer and an isotactic polymer, the atactic polymer having a degree of crystallinity of less than about 20% and a number-average molecular weight of from about 1,000 to about 300,000 and the isotactic polymer having a degree of crystallinity of at least about 40% and a number-average molecular weight of from about 3,000 to about 200,000.  
     
     
         38 . The absorbent article as set forth in  claim 37  wherein the degree of crystallinity of the atactic polymer is less than about 15%.  
     
     
         39 . The absorbent article as set forth in  claim 37  wherein the degree of crystallinity of the isotactic polymer is at least about 60%.  
     
     
         40 . The absorbent article as set forth in  claim 37  wherein the number-average molecular weight of the atactic polymer is between about 3,000 and about 100,000.  
     
     
         41 . The absorbent article as set forth in  claim 37  wherein the number-average molecular weight of the isotactic polymer is between about 10,000 and about 100,000.  
     
     
         42 . The absorbent article as set forth in  claim 37  wherein the adhesive composition is hot-melt processable at less than about 450 degrees Fahrenheit.  
     
     
         43 . The absorbent article as set forth in  claim 37  wherein the adhesive composition is hot-melt processable at less than about 350 degrees Fahrenheit.  
     
     
         44 . The absorbent article as set forth in  claim 37  wherein the adhesive composition has a melt index of from about 100 to about 2000 grams per 10 minutes.  
     
     
         45 . The absorbent article as set forth in  claim 37  wherein the adhesive composition comprises from about 50 to about 90 weight percent of the atactic polymer and from about 5 to about 50 weight percent of the isotactic polymer.  
     
     
         46 . The absorbent article as set forth in  claim 37  wherein the atactic polymer comprises atactic polypropylene.  
     
     
         47 . The absorbent article as set forth in  claim 37  wherein the atactic polymer is selected from the group consisting of low density polyethylene, ataxic polystyrene, ataxic polybutene, amorphous polyolefin copolymer, and combinations thereof.  
     
     
         48 . The absorbent article as set forth in  claim 47  wherein the low density polyethylene has a density in the range of 0.910 to 0.935 grams per cubic centimeter.  
     
     
         49 . The absorbent article as set forth in  claim 37  wherein the isotactic polymer comprises isotactic polypropylene.  
     
     
         50 . The absorbent article as set forth in  claim 37  wherein the isotactic polymer is selected from the group consisting of high density poylethylene, isotactic polystyrene, isotactic polybutene, and combinations thereof.  
     
     
         51 . The absorbent article as set forth in  claim 37  wherein the high density polyethylene has a density in the range of 0.935 to 0.980 grams per cubic centimeter.  
     
     
         52 . The absorbent article as set forth in  claim 37  wherein the first layer comprises a spunbond polypropylene and the second layer comprises cellulosic tissue paper.  
     
     
         53 . An absorbent article comprising a laminated structure, the laminated structure comprising a first layer comprising polyethylene and a second layer comprising a cellulosic material, the first layer and second layer being attached to each other using an adhesive composition comprising an atactic polymer and an isotactic polymer, the atactic polymer having a degree of crystallinity of less than about 20% and a number-average molecular weight of from about 1,000 to about 300,000 and the isotactic polymer having a degree of crystallinity of at least about 40% and a number-average molecular weight of from about 3,000 to about 200,000.  
     
     
         54 . The absorbent article as set forth in  claim 53  wherein the degree of crystallinity of the atactic polymer is less than about 15%.  
     
     
         55 . The absorbent article as set forth in  claim 53  wherein the degree of crystallinity of the isotactic polymer is at least about 60%.  
     
     
         56 . The absorbent article as set forth in  claim 53  wherein the number-average molecular weight of the atactic polymer is between about 3,000 and about 100,000.  
     
     
         57 . The absorbent article as set forth in  claim 53  wherein the number-average molecular weight of the isotactic polymer is between about 10,000 and about 100,000.  
     
     
         58 . The absorbent article as set forth in  claim 53  wherein the adhesive composition is hot-melt processable at less than about 450 degrees Fahrenheit.  
     
     
         59 . The absorbent article as set forth in  claim 53  wherein the adhesive composition is hot-melt processable at less than about 350 degrees Fahrenheit.  
     
     
         60 . The absorbent article as set forth in  claim 53  wherein the adhesive composition has a melt index of from about 100 to about 2000 grams per 10 minutes.  
     
     
         61 . The absorbent article as set forth in  claim 53  wherein the adhesive composition comprises from about 50 to about 90 weight percent of the atactic polymer and from about 5 to about 50 weight percent of the isotactic polymer.  
     
     
         62 . The absorbent article as set forth in  claim 53  wherein the atactic polymer comprises atactic polypropylene.  
     
     
         63 . The absorbent article as set forth in  claim 53  wherein the atactic polymer is selected from the group consisting of low density polyethylene, ataxic polystyrene, ataxic polybutene, amorphous polyolefin copolymer, and combinations thereof.  
     
     
         64 . The absorbent article as set forth in  claim 63  wherein the low density polyethylene has a density in the range of 0.910 to 0.935 grams per cubic centimeter.  
     
     
         65 . The absorbent article as set forth in  claim 53  wherein the isotactic polymer comprises isotactic polypropylene.  
     
     
         66 . The absorbent article as set forth in  claim 53  wherein the isotactic polymer is selected from the group consisting of high density poylethylene, isotactic polystyrene, isotactic polybutene, and combinations thereof.  
     
     
         67 . The absorbent article as set forth in  claim 53  wherein the high density polyethylene has a density in the range of 0.935 to 0.980 grams per cubic centimeter.  
     
     
         68 . An absorbent article comprising a laminated structure, the laminated structure comprising a first layer comprising polyethylene and a second layer comprising polyethylene, the first layer and second layer being attached to each other using an adhesive composition comprising an atactic polymer and an isotactic polymer, the atactic polymer having a degree of crystallinity of less than about 20% and a number-average molecular weight of from about 1,000 to about 300,000 and the isotactic polymer having a degree of crystallinity of at least about 40% and a number-average molecular weight of from about 3,000 to about 200,000.  
     
     
         69 . The absorbent article as set forth in  claim 68  wherein the degree of crystallinity of the atactic polymer is less than about 15%.  
     
     
         70 . The absorbent article as set forth in  claim 68  wherein the degree of crystallinity of the isotactic polymer is at least about 60%.  
     
     
         71 . The absorbent article as set forth in  claim 68  wherein the number-average molecular weight of the atactic polymer is between about 3,000 and about 100,000.  
     
     
         72 . The absorbent article as set forth in  claim 68  wherein the number-average molecular weight of the isotactic polymer is between about 10,000 and about 100,000.  
     
     
         73 . The absorbent article as set forth in  claim 68  wherein the adhesive composition is hot-melt processable at less than about 450 degrees Fahrenheit.  
     
     
         74 . The absorbent article as set forth in  claim 68  wherein the adhesive composition is hot-melt processable at less than about 350 degrees Fahrenheit.  
     
     
         75 . The absorbent article as set forth in  claim 68  wherein the adhesive composition has a melt index of from about 100 to about 2000 grams per 10 minutes.  
     
     
         76 . The absorbent article as set forth in  claim 68  wherein the adhesive composition comprises from about 50 to about 90 weight percent of the atactic polymer and from about 5 to about 50 weight percent of the isotactic polymer.  
     
     
         77 . The absorbent article as set forth in  claim 68  wherein the atactic polymer comprises atactic polypropylene.  
     
     
         78 . The absorbent article as set forth in  claim 68  wherein the atactic polymer is selected from the group consisting of low density polyethylene, ataxic polystyrene, ataxic polybutene, amorphous polyolefin copolymer, and combinations thereof.  
     
     
         79 . The absorbent article as set forth in  claim 78  wherein the low density polyethylene has a density in the range of 0.910 to 0.935 grams per cubic centimeter.  
     
     
         80 . The absorbent article as set forth in  claim 68  wherein the isotactic polymer comprises isotactic polypropylene.  
     
     
         81 . The absorbent article as set forth in  claim 68  wherein the isotactic polymer is selected from the group consisting of high density poylethylene, isotactic polystyrene, isotactic polybutene, and combinations thereof.  
     
     
         82 . The absorbent article as set forth in  claim 68  wherein the high density polyethylene has a density in the range of 0.935 to 0.980 grams per cubic centimeter.  
     
     
         83 . An absorbent article comprising a laminated structure, the laminated structure comprising a first layer comprising a cellulosic material and a second layer comprising a cellulosic material, the first layer and second layer being attached to each other using an adhesive composition comprising an atactic polymer and an isotactic polymer, the atactic polymer having a degree of crystallinity of less than about 20% and a number-average molecular weight of from about 1,000 to about 300,000 and the isotactic polymer having a degree of crystallinity of at least about 40% and a number-average molecular weight of from about 3,000 to about 200,000.  
     
     
         84 . The absorbent article as set forth in  claim 83  wherein the degree of crystallinity of the atactic polymer is less than about 15%.  
     
     
         85 . The absorbent article as set forth in  claim 83  wherein the degree of crystallinity of the isotactic polymer is at least about 60%.  
     
     
         86 . The absorbent article as set forth in  claim 83  wherein the number-average molecular weight of the atactic polymer is between about 3,000 and about 100,000.  
     
     
         87 . The absorbent article as set forth in  claim 83  wherein the number-average molecular weight of the isotactic polymer is between about 10,000 and about 100,000.  
     
     
         88 . The absorbent article as set forth in  claim 83  wherein the adhesive composition is hot-melt processable at less than about 450 degrees Fahrenheit.  
     
     
         89 . The absorbent article as set forth in  claim 83  wherein the adhesive composition is hot-melt processable at less than about 350 degrees Fahrenheit.  
     
     
         90 . The absorbent article as set forth in  claim 83  wherein the adhesive composition has a melt index of from about 100 to about 2000 grams per 10 minutes.  
     
     
         91 . The absorbent article as set forth in  claim 83  wherein the adhesive composition comprises from about 50 to about 90 weight percent of the atactic polymer and from about 5 to about 50 weight percent of the isotactic polymer.  
     
     
         92 . The absorbent article as set forth in  claim 83  wherein the atactic polymer comprises atactic polypropylene.  
     
     
         93 . The absorbent article as set forth in  claim 83  wherein the atactic polymer is selected from the group consisting of low density polyethylene, ataxic polystyrene, ataxic polybutene, amorphous polyolefin copolymer, and combinations thereof.  
     
     
         94 . The absorbent article as set forth in  claim 93  wherein the low density polyethylene has a density in the range of 0.910 to 0.935 grams per cubic centimeter.  
     
     
         95 . The absorbent article as set forth in  claim 83  wherein the isotactic polymer comprises isotactic polypropylene.  
     
     
         96 . The absorbent article as set forth in  claim 83  wherein the isotactic polymer is selected from the group consisting of high density poylethylene, isotactic polystyrene, isotactic polybutene, and combinations thereof.  
     
     
         97 . The absorbent article as set forth in  claim 83  wherein the high density polyethylene has a density in the range of 0.935 to 0.980 grams per cubic centimeter.