# US 2008/0076844 A1 · Fibrillated polyolefin foam

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- Number: US 2008/0076844 A1
- Document ID: US20080076844A1
- Status: Published application
- Kind: A1
- Application number: 11/525,551
- Filed: 2006-09-22
- Published: 2008-03-27
- Earliest claimed: 2006-09-22
- Assignees: The Dow Chemical Company
- Inventors: Mark W. Van Sumeren; Luther Stockton; Sue Machelski
- Web page: https://patentgrep.com/patent/US20080076844A1

## CPC

- B29C 67/202: {comprising elimination of a solid or a liquid ingredient}
- A61L 15/24: Macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds; Derivatives thereof {(A61L15/225 takes precedence)}
- A61L 15/425: {Porous materials, e.g. foams or sponges}
- C08J 9/0085: {Use of fibrous compounding ingredients (C08J9/0076 takes precedence)}
- C08J 9/30: by mixing gases into liquid compositions or plastisols, e.g. frothing with air
- B29C: SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING (making preforms B29B11/00; making laminated products by combining previously unconnected layers which become one product whose layers will remain together B32B37/00 - B32B41/00)
- A61L: METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES (preservation of bodies or disinfecting characterised by the agents employed A01N; preserving, e.g. sterilising, food or foodstuffs A23; preparations for medical, dental or toiletry purposes A61K)
- C08J: WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H (working, e.g. shaping, of plastics B29)

## Abstract

A method for generating a thermoplastic foam from an aqueous dispersion, the aqueous dispersion comprising a thermoplastic resin, water, and a dispersion stabilizing agent, the method including: adding at least one froth stabilizing surfactant to the aqueous dispersion to form a mixture; adding a fiber to the mixture; and frothing the mixture to create a froth, removing at least a portion of the water in the froth to create a foam, wherein the foam generated has a non-cellular fibrillated morphology. In another aspect, embodiments disclosed herein relate to a foam having a thermoplastic-based, fibrillated, non-cellular structure, wherein the foam has an average density of about 0.02 g/cm3 to about 0.07 g/cm3. In certain embodiments, the foam may be used in an absorbent article.

## Claims

### Claim 1

A method for generating a thermoplastic foam from an aqueous dispersion, the aqueous dispersion comprising a thermoplastic resin, water, and a dispersion stabilizing agent, the method comprising:
adding at least one froth stabilizing surfactant to the aqueous dispersion to form a mixture;
adding fiber to the mixture; and
frothing the mixture to create a froth,
removing at least a portion of the water in the froth to create a foam,
wherein the foam generated has a non-cellular fibrillated morphology.

### Claim 2

(canceled)

### Claim 3

(canceled)

### Claim 4 (depends on 1)

The method of claim 1, further comprising:
coating at least a portion of a substrate with a layer of the froth; and
removing a majority of the water from the froth.

### Claim 5

(canceled)

### Claim 6

(canceled)

### Claim 7

(canceled)

### Claim 8

(canceled)

### Claim 9

(canceled)

### Claim 10

(canceled)

### Claim 11

(canceled)

### Claim 12

(canceled)

### Claim 13 (depends on 1)

The method of claim 1, wherein the removing at least a portion of the water in the froth to create a foam results in a foam having from 0 to 20 weight percent residual water.

### Claim 14

A foam comprising:
a thermoplastic-based, fibrillated, non-cellular structure;
wherein the foam has an average density of about 0.02 g/cm3 to about 0.07 g/cm3.

### Claim 15 (depends on 14)

The foam of claim 14, wherein the foam comprises from about 10 weight percent to about 60 weight percent fiber.

### Claim 16 (depends on 15)

The foam of claim 15, wherein the fiber comprises a polyethylene homopolymer, copolymer, or multiblock interpolymer, a polypropylene homopolymer, copolymer, or multiblock interpolymer, synthetic pulp, or combinations thereof.

### Claim 17 (depends on 15)

The foam of claim 15, wherein the fiber has an average length of from about 0.5 mm to about 20 mm.

### Claim 18 (depends on 15)

The foam of claim 15, wherein at least about 50% of a surface area of the fibers are coated with a thermoplastic resin.

### Claim 19 (depends on 18)

The foam of claim 18, wherein the thermoplastic resin is at least partially crosslinked.

### Claim 20 (depends on 18)

The foam of claim 18, wherein the thermoplastic resin comprises a polyolefin.

### Claim 21 (depends on 14)

The foam of claim 14, wherein the foam has an average thickness from about 0.01 cm to about 2.5 cm.

### Claim 22 (depends on 14)

The foam of claim 14, wherein the foam has an insult strike through rate of 0.1 to 10 seconds.

### Claim 23

(canceled)

### Claim 24 (depends on 14)

The foam of claim 14, further comprising a superabsorbent polymer.

### Claim 25 (depends on 14)

An absorbent article selected from a baby diaper, a feminine hygiene product, an adult incontinence product, a wound dressing pad, a surgical sponge, a medical garment, a surgical drapery, a wiping towel, a wiping sponge, and a food packaging pad, comprising the foam of claim 14.

### Claim 26

A method for generating a thermoplastic foam from an aqueous dispersion, the aqueous dispersion comprising a thermoplastic resin, water, and a dispersion stabilizing agent, the method comprising:
adding at least one froth stabilizing surfactant to the aqueous dispersion to form a mixture;
adding fiber to the mixture; and
frothing the mixture to create a froth;
removing at least a portion of the water in the froth to create a foam;
wherein the foam created comprises 20 weight percent or less residual water; and
wherein the foam generated has a non-cellular fibrillated morphology.

### Claim 27

(canceled)

### Claim 28

(canceled)

### Claim 29 (depends on 26)

The method of claim 26, wherein the dispersion stabilizing agent comprises a fatty acid.

### Claim 30 (depends on 26)

The method of claim 26, wherein the froth stabilizing surfactant comprises cellulose.

### Claim 31 (depends on 26)

The method of claim 26, further comprising coating at least a portion of a substrate with a layer of the froth.

### Claim 32 (depends on 26)

The method of claim 26, wherein the dispersion comprises from about 25 to about 74% thermoplastic resin and dispersion stabilizing agent by volume of the dispersion.

### Claim 33

(canceled)

### Claim 34 (depends on 33)

The method of claim 33, wherein the thermoplastic resin comprises a polyolefin.

### Claim 35 (depends on 26)

The method of claim 26, wherein the foam comprises from about 10 weight percent to about 60 weight percent fiber based on the combined weight of the thermoplastic resin and fiber.

### Claim 36 (depends on 26)

The method of claim 26, wherein the fiber comprises a polyethylene homopolymer, copolymer, or multiblock interpolymer, a polypropylene homopolymer, copolymer, or multiblock interpolymer, synthetic pulp, or combinations thereof.

### Claim 37 (depends on 26)

The method of claim 26, wherein the fiber has an average length of from about 0.5 mm to about 20 mm.

### Claim 38 (depends on 26)

The method of claim 26, wherein the fibers have a melting point greater than the thermoplastic resin.

### Claim 39 (depends on 26)

The method of claim 26, wherein the foam has at least one layer having an average thickness of from about 0.01 cm to about 2.5 cm.