Flushable fibrous structures

• US 6,127,593 A
• Filed: 11/25/1997
• Issued: 10/03/2000
• Est. Priority Date: 11/25/1997
• Status: Expired due to Term

• Current Assignee: The Procter & Gamble Company
• Original Assignee: The Procter & Gamble Company
• Inventors: Mansfield, Todd Leon, Bjorkquist, David William
• Primary Examiner(s): Polutta, Mark O.
• Application Number:
  US08/976,746
• Time in Patent Office: 1,043 Days
• Field of Search: 604/364, 604/367, 604/365, 604/370, 604/372, 604/374, 604/375, 604/376, 604/377, 525/54.3, 525/61, 442/119, 428/475.8, 428/511, 428/913
• US Class Current: 604/364
• CPC Class Codes: A61L 15/24 Macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds; Derivatives thereof A61L15/225 takes precedence
• CPC Class Codes: A61L 15/62 Compostable, hydrosoluble or hydrodegradable materials
• CPC Class Codes: C08L 33/14 of esters containing halogen, nitrogen, sulfur, or oxygen atoms in addition to the carboxy oxygen
• CPC Class Codes: D21H 17/36 Polyalkenyalcohols; Polyalkenylethers; Polyalkenylesters
• CPC Class Codes: D21H 17/37 Polymers of unsaturated acids or derivatives thereof, e.g. polyacrylates
• CPC Class Codes: D21H 17/66 Salts, e.g. alums
• CPC Class Codes: D21H 21/20 Wet strength agents
• CPC Class Codes: Y10S 428/913 Material designed to be responsive to temperature, light, moisture
• CPC Class Codes: Y10T 428/31743 Next to addition polymer from unsaturated monomer[s]
• CPC Class Codes: Y10T 442/2492 Polyether group containing

Abstract

The present invention relates to a flushable fibrous structure that is particularly useful as a disposable tissue product and as a component (e.g., topsheets) for absorbent articles such as catamenial pads, diapers, incontinent articles and the like. The invention specifically relates to a flushable fibrous structure that has an in-use wet tensile strength of at least about 100 g/in. and a disposal wet tensile strength of not more than about 30 g/in. The invention also relates to absorbent articles comprising the fibrous structures, and methods for making the structures.

Claims

1. A flushable fibrous structure having an in-use wet tensile strength of at least about 100 g/in. and a disposable wet tensile strength of not more than about 30 g/in. wherein said flushable fibrous structure comprises fibers, a salt, and a polymer.

2. The flushable fibrous structure of claim 1 wherein the polymer is the condensation product derived from reacting polyvinyl alcohol and one or more substituted or unsubstituted C₁ -C₈ aldehydes.

3. The flushable fibrous structure of claim 2 wherein the polyvinyl alcohol reacted to form the polymer has a degree of hydrolysis prior to condensation of at least about 95%.

4. The flushable fibrous structure of claim 3 wherein the polyvinyl alcohol reacted to form the polymer has a degree of hydrolysis prior to condensation of at least about 97%.

5. The flushable fibrous structure of claim 4 wherein the polyvinyl alcohol reacted to form the polymer has a degree of hydrolysis prior to condensation of at least about 98%.

6. The flushable fibrous structure of claim 2 wherein the aldehyde reacted to form the polymer has from 2 to 5 carbon atoms.

7. The flushable fibrous structure of claim 6 wherein the aldehyde reacted to form the polymer is propionaldehyde, butyraldehyde, or a mixture thereof.

8. The flushable fibrous structure of claim 2 wherein the polymer is derived from the condensation of at least about 8% of the hydroxyl groups of the starting polyvinyl alcohol.

9. The flushable fibrous structure of claim 8 wherein the polymer is derived from the condensation of from about 8% to about 20% of the hydroxyl groups of the starting polyvinyl alcohol.

10. The flushable fibrous structure of claim 9 wherein the polymer is derived from the condensation of from about 10% to about 16% of the hydroxyl groups of the starting polyvinyl alcohol.

11. The flushable fibrous structure of claim 1 wherein the salt is selected from the group consisting of sodium citrate, sodium sulfate, potassium sulfate, sodium phosphate, potassium phosphate, magnesium sulfate, magnesium chloride, calcium sulfate, and mixtures thereof.

12. The flushable fibrous structure of claim 11 wherein the salt is selected from the group consisting of potassium citrate, sodium sulfate, and mixtures thereof.

13. The flushable fibrous structure of claim 1 wherein the polymer constitutes from about 0.5 weight % to about 20 weight % of the fibrous structure.

14. The flushable fibrous structure of claim 1 wherein the polymer has a structure according to formula (I) ##STR2## wherein (a) x is ≧

1;

(b) y is ≧

0;

(c) R¹ and R² are independently selected from hydrogen and C₁ -C₆ alkyl; and

(d) when y is ≧

1,

(i) R³ is --N(R⁴) (R⁵), where R⁴ and R⁵ are independently selected from hydrogen, C₁ -C₆ alkyl, and aryl;

or

(ii) R³ is --O--(--CH₂ --)_z --N(R⁶) (R⁷), where z is from 2 to about 4 and R⁶ and R⁷ are independently selected from hydrogen C₁ -C₆ alkyl, and aryl.

15. The flushable fibrous structure of claim 14 wherein y is 0;

R¹ is hydrogen or C₁ -C₃ alkyl; and

R² is C₁ -C₃ alkyl.

16. The flushable fibrous structure of claim 15 wherein R¹ is hydrogen and R² is methyl, ethyl, isopropyl, or n-propyl.

17. The flushable fibrous structure of claim 14 wherein y is ≧

1 and

(a) R³ is --N(R⁴) (R⁵) where R⁴ is hydrogen or C₁ -C₄ alkyl and R⁵ is C₁ -C₄ alkyl;

or

(b) R³ is --O--(--CH₂ --)_z --N(R⁶) (R⁷) where z is 2 or 3, R⁶ is hydrogen or C₁ -C₃ alkyl and R⁷ is C₁ -C₃ alkyl.

18. The flushable fibrous structure of claim 17 where

(a) R³ is --N(R⁴) (R⁵, where R⁴ is hydrogen or C₃ -C₄ alkyl and R⁵ is C₃ -C₄ alkyl;

or

(b) R³ is --O--(--CH₂ --)_z --N(R⁶) (R⁷), where R⁶ is C₁ -C₃ alkyl and R⁷ is C₁ -C₃ alkyl.

30. A disposable absorbent article comprising:

A. a liquid pervious topsheet;

B. a liquid impervious backsheet; and

C. an absorbent core positioned between the topsheet and the backsheet;

wherein the topsheet comprises the flushable fibrous structure of claim 1.

31. A disposable absorbent article comprising:

A. a liquid pervious topsheet;

B. a liquid impervious backsheet; and

C. an absorbent core positioned between the topsheet and the backsheet;

wherein the topsheet comprises the flushable fibrous structure of claim 2.

32. A disposable absorbent article comprising:

A. a liquid pervious topsheet;

B. a liquid impervious backsheet; and

C. an absorbent core positioned between the topsheet and the backsheet;

wherein the topsheet comprises the flushable fibrous structure of claim 9.

33. A disposable absorbent article comprising:

A. a liquid pervious topsheet;

B. a liquid impervious backsheet; and

C. an absorbent core positioned between the topsheet and the backsheet;

wherein the topsheet comprises the flushable fibrous structure of claim 14.

19. A flushable fibrous structure comprising fibers, a salt, and a polymer which is the condensation product derived from reacting polyvinyl alcohol and one or more substituted or unsubstituted C₁ -C₈ aldehydes.

20. The flushable fibrous structure of claim 19 wherein the polyvinyl alcohol reacted to form the polymer has a degree of hydrolysis prior to condensation of at least about 95%.

21. The flushable fibrous structure of claim 20 wherein the polyvinyl alcohol reacted to form the polymer has a degree of hydrolysis prior to condensation of at least about 98%.

22. The flushable fibrous structure of claim 19 wherein the polyvinyl is derived from the condensation of at least about 8% of the hydroxyl groups of the starting polyvinyl alcohol.

23. The flushable fibrous structure of claim 22 wherein the polymer is derived from the condensation of from about 10% to about 16% of the hydroxyl groups of the starting polyvinyl alcohol.

34. A disposable absorbent article comprising:

A. a liquid pervious topsheet;

B. a liquid impervious backsheet; and

C. an absorbent core positioned between the topsheet and the backsheet;

wherein the topsheet comprises the flushable fibrous structure of claim 19.

24. A flushable fibrous structure comprising fibers, a salt, and a polymer which is the condensation product derived from reacting (i) polyvinyl alcohol having a degree of hydrolysis prior to condensation of at least about 95% and (ii) one or more substituted or unsubstituted C₁ -C₈ aldehydes;

wherein the polymer is derived from the condensation of from about 8% to about 20% of the hydroxyl groups of the starting polyvinyl alcohol (i).

35. A disposable absorbent article comprising:

A. a liquid pervious topsheet;

B. a liquid impervious backsheet; and

C. an absorbent core positioned between the topsheet and the backsheet;

wherein the topsheet comprises the flushable fibrous structure of claim 24.

25. A flushable fibrous structure comprising fibers, a salt, and a polymer which has a structure according to formula (I) ##STR3## wherein (a) x is ≧

1;

(b) y is ≧

0;

(c) R¹ and R² are independently selected from hydrogen and C₁ -C₃ alkyl; and

(d) when y is ≧

1,

(i) R³ is --N(R⁴) (R⁵), where R⁴ and R⁵ are independently selected from hydrogen, C₁ -C₆ alkyl, and aryl;

or

(ii) R³ is --O--(--CH₂ --)_z --N(R⁶) (R⁷), where z is from 2 to about 4 and R⁶ and R⁷ are independently selected from hydrogen C₁ -C₆ alkyl, and aryl.

26. The flushable fibrous structure of claim 25 wherein y is 0;

R¹ is hydrogen or C₁ -C₃ alkyl; and

R² is C₁ -C₃ alkyl.

27. The flushable fibrous structure of claim 26 wherein R¹ is hydrogen and R² is methyl, ethyl, isopropyl, or n-propyl.

28. The flushable fibrous structure of claim 25 wherein y is ≧

1 and

(a) R³ is --N(R⁴) (R⁵, where R⁴ is hydrogen or C₁ -C₄ alkyl and R⁵ is C₁ -C₄ alkyl;

or

(b) R³ is --O--(--CH₂ --)_z --N(R⁶) (R⁷), where z is 2 or 3, R⁶ is hydrogen or C₁ -C₃ alkyl and R⁷ is C₁ -C₃ alkyl.

29. The flushable fibrous structure of claim 28 where

(a) R³ is --N(R⁴) (R⁵, where R⁴ is hydrogen or C₃ -C₄ alkyl and R⁵ is C₃ -C₄ alkyl;

or

(b) R³ is --O--(--CH₂ --)_z --N(R⁶) (R⁷), where R⁶ is C₁ -C₃ alkyl and R⁷ is C₁ -C₃ alkyl.

36. A disposable absorbent article comprising:

A. a liquid pervious topsheet;

B. a liquid impervious backsheet; and

C. an absorbent core positioned between the topsheet and the backsheet;

wherein the topsheet comprises the flushable fibrous structure of claim 25.