Soft and durable nonwoven web

Patent metadata

Field	Value
Publication number	US-11083816-B2
Application number	US-201415517540-A
Country	US
Kind code	B2
Filing date	Nov 18, 2014
Priority date	Nov 18, 2014
Publication date	Aug 10, 2021
Grant date	Aug 10, 2021

Abstract

A nonwoven web that contains a plurality of fibers formed from a polyolefin composition is provided. The polyolefin composition contains a rigid propylene polymer that has a relatively high melting temperature and modulus of elasticity, which can provide good strength and durability to the nonwoven web. The polyolefin composition also contains a ductile propylene polymer that has a relatively high melt flow index, which can help achieve relatively fine fibers that minimize the stiffness of the web. In addition to a rigid and ductile polymer, the polyolefin composition also contains a slip additive (e.g., fatty acid derivative). Among other things, such an additive can even further enhance the overall softness of the composition.

First claim

What is claimed is:

1. A nonwoven web comprising a plurality of fibers formed from a polyolefin composition, wherein the polyolefin composition contains
at least one rigid propylene polymer,
from about 0.5 wt. % to about 20 wt. % based upon the polyolefin composition of at least one ductile propylene polymer, and
from 0.5 wt. % to about 6 wt. % based upon the polyolefin composition of at least one slip additive, wherein a weight ratio of the at least one ductile propylene polymer to the slip additive is from about 1 to about 30, and
further wherein the ductile propylene polymer has a melt flow index of about 1,500 grams to about 5,000 grams per 10 minutes, and the rigid propylene polymer has a melt flow index of about 15 grams to about 80 grams per 10 minutes, as determined at a load of 2160 grams and at 230° C. in accordance with ASTM D1238-13.

2. The nonwoven web of claim 1 , wherein the polyolefin composition has a melting temperature of from about 50° C. to about 145° C.

3. The nonwoven web of claim 1 , wherein the rigid propylene polymer has a modulus of elasticity of from about 800 to about 4,000 MPa, as determined in accordance with ASTM D638-10.

4. The nonwoven web of claim 1 , wherein the rigid propylene polymer is an isotactic homopolymer.

5. The nonwoven web of claim 1 , wherein the rigid propylene polymer constitutes from about 75 wt. % to about 99.5 wt. % of the polyolefin composition.

6. The nonwoven web of claim 1 , wherein the ratio of the modulus of elasticity of the rigid propylene polymer to the modulus of elasticity of the ductile propylene polymer is from about 1 to about 50, as determined in accordance with ASTM D638-10.

7. The nonwoven web of claim 6 , wherein the modulus of elasticity of the ductile propylene polymer is from about 1 to about 500 MPa, as determined in accordance with ASTM D638-10.

8. The nonwoven web of claim 1 , wherein the ductile propylene polymer has a melting temperature of from about 40° C. to about 120° C.

9. The nonwoven web of claim 1 , wherein the ductile propylene polymer has a degree of crystallinity of from about 1% to about 35%, as determined using differential scanning calorimetry in accordance with ASTM D-3417.

10. The nonwoven web of claim 1 , wherein the ductile propylene polymer is a metallocene-catalyzed homopolymer.

11. The nonwoven web of claim 1 , wherein the ductile propylene polymer constitutes from about 0.5 wt. % to about 15 wt. % of the polyolefin composition and/or the slip additive constitutes from 0.5 wt. % to about 3 wt. % of the polyolefin composition.

12. The nonwoven web of claim 1 , wherein the slip additive includes a fatty acid derivative, and preferably a fatty acid amide, such as erucamide, oleamide, or a combination thereof.

13. The nonwoven web of claim 1 , wherein the fibers have a denier of from about 3 or less.

14. The nonwoven web of claim 1 , wherein the nonwoven web is a spunbond web.

15. The nonwoven web of claim 1 , wherein the nonwoven web exhibits a cup crush load of about 200 grams-force or less and/or a coefficient of friction in the machine direction of about 0.885 or less.

16. A composite comprising the nonwoven web of claim 1 and at least one additional layer.

17. The composite of claim 16 , wherein the additional layer includes a second nonwoven web that contains a plurality of fibers formed from a second polyolefin composition, wherein the second polyolefin composition contains at least one ethylene polymer.

18. The composite of claim 16 , wherein the nonwoven web constitutes from about 20 wt. % to about 80 wt. % of the composite and the additional layer constitutes from about 20 wt. % to about 80 wt. % of the composite.

19. The composite of claim 16 , wherein the additional layer includes a film.

20. An absorbent article comprising an absorbent core positioned between a backsheet and a topsheet, wherein the backsheet, topsheet, or both contains the nonwoven web of claim 1 .

21. The nonwoven web of claim 1 , wherein the at least one ductile propylene polymer comprises at least one ductile propylene homopolymer.

Assignees

• Kimberly Clark Co

Inventors

• Kupelian Mark G
• Huang Lei
• Conrad John H
• Krueger Jeffrey J
• Sterling Ray A

Classifications

• D04H1/4291 Primary

  Olefin series · CPC title

• D04H5/00

  Non woven fabrics formed of mixtures of relatively short fibres and yarns or like filamentary material of substantial length · CPC title

• A61F13/15

  Absorbent pads, e.g. sanitary towels, swabs or tampons for external or internal application to the body; Supporting or fastening means therefor; Tampon applicators · CPC title

• A61L15/225 Primary

  Mixtures of macromolecular compounds · CPC title

• D01F6/46

  of polyolefins · CPC title