Thermoplastic polymer blends and nonwoven webs prepared therefrom

• US 4,806,598 A
• Filed: 12/22/1986
• Issued: 02/21/1989
• Est. Priority Date: 12/22/1986
• Status: Expired due to Term

• Current Assignee: Kimberly-Clark Worldwide Incorporated (Kimberly-Clark Corporation)
• Original Assignee: Kimberly-Clark Corporation
• Inventors: Morman, Michael T.
• Primary Examiner(s): CANNON, JAMES
• Application Number:
  US06/945,753
• Time in Patent Office: 792 Days
• Field of Search: 525/63, 525/64, 525/88, 525/128, 525/130, 525/173, 525/176, 525/177, 525/184, 525/403, 525/408, 525/409, 525/430, 525/437, 525/458
• US Class Current: 525/63
• CPC Class Codes: A61F 13/202 Catamenial tampons A61F13/2022-A61F13/34 take precedence
• CPC Class Codes: A61F 13/53 characterised by the absorbing medium A61F13/20 takes precedence
• CPC Class Codes: A61F 2013/530131 being made in fibre but being not pulp
• CPC Class Codes: A61F 2013/530481 having superabsorbent materials, i.e. highly absorbent polymer gel materials
• CPC Class Codes: A61L 15/60 Liquid-swellable gel-forming materials, e.g. super-absorbents
• CPC Class Codes: C08G 18/10 Prepolymer processes involving reaction of isocyanates or isothiocyanates with compounds having active hydrogen in a first reaction step
• CPC Class Codes: C08G 18/3206 aliphatic
• CPC Class Codes: C08G 18/4833 Polyethers containing oxyethylene units
• CPC Class Codes: C08G 81/00 Macromolecular compounds obtained by interreacting polymers in the absence of monomers, e.g. block polymers involving only carbon-to-carbon unsaturated bond reactions C08F299/00 ; polyester-amides C08G69/44; polyester-imides C08G73/16; polyamides-imides C08G73/14; block- or graft polymers containing polysiloxane sequences C08G77/42
• CPC Class Codes: C08L 75/08 from polyethers
• CPC Class Codes: D04H 1/407 containing absorbing substances, e.g. activated carbon
• CPC Class Codes: D04H 1/4291 Olefin series
• CPC Class Codes: D04H 1/4334 Polyamides
• CPC Class Codes: D04H 1/435 Polyesters
• CPC Class Codes: D04H 1/4358 Polyurethanes
• CPC Class Codes: D04H 1/43828 sheath-core
• CPC Class Codes: D04H 1/43832 side-by-side
• CPC Class Codes: D04H 1/43835 Mixed fibres, e.g. at least two chemically different fibres or fibre blends
• CPC Class Codes: D04H 1/43838 Ultrafine fibres, e.g. microfibres
• CPC Class Codes: Y10S 428/913 Material designed to be responsive to temperature, light, moisture
• CPC Class Codes: Y10T 442/637 : Including strand or fiber material which is a monofilament composed of two or more polymeric materials in physically distinct relationship [e.g., sheath-core, side-by-side, islands-in-sea, fibrils-in-matrix, etc.] or composed of physical blend of chemically different polymeric materials or a physical blend of a polymeric material and a filler material
• CPC Class Codes: Y10T 442/68 : Melt-blown nonwoven fabric
• CPC Class Codes: Y10T 442/681 : Spun-bonded nonwoven fabric

Abstract

A stable, nonreactive, thermoplastic polymer blend comprising from about 10 to about 95 percent by weight of a superabsorbent, thermoplastic polymeric composition and from about 90 to about 5 percent by weight of at least one thermoplastic polymer.

The superabsorbent, thermoplastic polymeric composition preferably comprises:

(A) from about 86 to about 98 percent by weight, based on the total weight of the composition, of a poly(oxyethylene) diol soft segment having a weight average molecular weight in the range of from about 5,000 to about 50,000; and

(B) from about 2 to about 14 percent by weight, based on the total weight of the composition, of a hard segment which has a melting point above ambient temperature and below the temperature at which decomposition of either the composition or the soft segment takes place, is essentially insoluble in water, and phase separates from the soft segment, said hard segment being selected from the group consisting of polyurethanes, polyamides, polyesters, polyureas, and combinations thereof;

wherein the soft and hard segments are covalently bound together by means of urethane, amide, ester, or secondary urea linkages or combinations thereof.

The blends are especially well suited for the preparation of nonwoven webs by meltblowing, coforming and spunbonding processes.

Claims

1. A stable, non-reactive, thermoplastic polymer blend comprising (a) from about 10 to about 95 percent by weight of superabsorbent, thermoplastic polymeric composition characterized by a poly(oxyethylene) group-containing, functional group-terminated soft segment covalently bonded to a hard segment through reaction with a third segment which may be monomeric or polymeric, and (b) from about 90 to about 5 percent by weight of at least one thermoplastic polymer.

2. The blend of claim 1, in which said polymeric composition comprises from about 30 to about 90 percent by weight of said blend.

3. The blend of claim 2, in which said polymeric composition comprises from about 40 to about 75 percent by weight of said blend.

4. The blend of claim 3, in which said at least one thermoplastic polymer is a polyolefin.

5. The blend of claim 4, in which said polyolefin is polypropylene or polyethylene.

6. The blend of claim 1, in which said polymeric composition comprises:

(A) from about 86 to about 98 percent by weight, based on the total weight of the composition, of a poly(oxyethylene) soft segment having a weight average molecular weight in the range of from about 5,000 to about 50,000; and

(B) from about 2 to about 14 percent by weight, based on the total weight of the composition, of a hard segment which has a melting point about ambient temperature and below the temperature at which decomposition of either the composition or the soft segment takes place, is essentially insoluble in water, and phase separates from the soft segment, said hard segment being selected from the group consisting of polyurethanes, polyamides, polyesters, polyureas, and combinations thereof;

wherein the soft and hard segments are covalently bound together by means of urethane, amide, ester, or secondary urea linkages or combinations thereof through reaction with a third segment which may be monomeric or polymeric.

7. The blend of claim 4, in which said polymeric composition comprises:

(A) from about 86 to about 98 percent by weight, based on the total weight of the composition, of a poly(oxyethylene) soft segment having a weight average molecular weight in the range of from about 5,000 to about 50,000; and

(B) from about 2 to about 14 percent by weight, based on the total weight of the composition, of a hard segment which has a melting point about ambient temperature and below the temperature at which decomposition of either the composition or the soft segment takes place, is essentially insoluble in water, and phase separates from the soft segment, said hard segment being selected from the group consisting of polyurethanes, polyamides, polyesters, polyureas, and combinations thereof;

wherein the soft and hard segments are covalently bound together by means of urethane, amide, ester, or secondary urea linkages or combinations thereof through reaction with a third segment which may be monomeric or polymeric.

8. The blend of claim 7, in which the weight average molecular weight of said soft segment is in the range of from about 8,000 to about 50,000.

9. The blend of claim 8, in which the weight average molecular weight of said soft segment is in the range of from about 8,000 to about 30,000.

10. The blend of claim 9, which the weight average molecular weight of said soft segment is in the range of from about 8,000 to about 16,000.

11. The blend of claim 7, in which said soft segment is present in the range of from about 90 to about 97 percent by weight.

12. The blend of claim 11, in which said soft segment is present in the range of from about 95 to 97 percent by weight.

13. The blend of claim 7, in which said hard segment is present in the range of from about 3 to about 10 percent by weight.

14. The blend of claim 13, in which said hard segment is present in the range of from about 3 to about 5 percent by weight.

15. The blend of claim 7, in which said soft segment is derived from a poly(oxyethylene) diol.

16. The blend of claim 15, in which said hard segment is a polyurethane.

17. The blend of claim 16, in which said polyurethane is derived from 1,4-butanediol.