# US 11,306,192 B2 · Polylactide foams

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- Number: US 11,306,192 B2
- Document ID: US11306192B2
- Status: Granted
- Kind: B2
- Application number: 16/287,331
- Filed: 2019-02-27
- Published: 2019-08-29
- Granted: 2022-04-19
- Earliest claimed: 2018-02-27
- Assignees: Regents of the University of Minnesota
- Applicants: Regents of the University of Minnesota
- Inventors: Philip T. Dirlam; David J. Goldfeld; Marc A. Hillmyer
- Web page: https://patentgrep.com/patent/US11306192B2

## CPC

- C08J 9/0023: {containing oxygen}
- C08J 9/0066: {Use of inorganic compounding ingredients}
- C08J 9/122: {Hydrogen, oxygen, CO2, nitrogen or noble gases}
- C08G 63/08: Lactones or lactides
- C08J 2203/06: CO2, N2 or noble gases
- C08J 2205/05: Open cells, i.e. more than 50% of the pores are open
- C08J 2367/04: Polyesters derived from hydroxy carboxylic acids, e.g. lactones (C08J2367/06 takes precedence)
- C08J 2471/02: Polyalkylene oxides
- 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)
- C08G: MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS

## Abstract

A foam that includes a polylactide polymer in the form of a star polymer having at least three arms. The foam is an open cell foam having a density no greater than 0.1 g/cm3.

## Claims

### Claim 1

A foam comprising a polylactide polymer in the form of a star polymer having at least three arms, wherein the foam is an open cell foam having a density no greater than 0.1 g/cm3.

### Claim 2 (depends on 1)

The foam of claim 1 wherein the foam has a density no greater than 0.06 g/cm3.

### Claim 3 (depends on 1)

The foam of claim 1 wherein the foam has a density no greater than 0.04 g/cm3.

### Claim 4 (depends on 1)

The foam of claim 1 wherein the foam further comprises a polysorbate surfactant.

### Claim 5 (depends on 4)

The foam of claim 4 wherein the polysorbate surfactant is selected from the group consisting of polysorbate 20, polysorbate 40, polysorbate 60, polysorbate 80, and combinations thereof.

### Claim 6 (depends on 4)

The foam of claim 4 wherein the polysorbate surfactant is present in an amount no greater than 5 wt. % based on the total weight of the foam.

### Claim 7 (depends on 1)

The foam of claim 1 wherein the foam further comprises a polyalkylene oxide block copolymer surfactant.

### Claim 8 (depends on 1)

The foam of claim 1 wherein the polyalkylene oxide block copolymer surfactant comprises a polyethylene oxide-polypropylene oxide-polyethylene oxide triblock copolymer surfactant.

### Claim 9 (depends on 1)

The foam of claim 1 wherein the polyalkylene oxide block copolymer surfactant is selected from the group consisting of Poloxamer 188, Poloxamer 338, Poloxamer 403, and combinations thereof.

### Claim 10 (depends on 7)

The foam of claim 7 wherein the polyalkylene oxide block copolymer surfactant is present in an amount at least 7.5 wt. % based on the total weight of the foam.

### Claim 11 (depends on 1)

The foam of claim 1 wherein the foam further comprises a polysorbate surfactant and a polyalkylene oxide block copolymer surfactant.

### Claim 12 (depends on 1)

The foam of claim 1 wherein the star polymer has at least four arms.

### Claim 13 (depends on 1)

The foam of claim 1 wherein the foam has a water uptake relative to void volume of at least 25%.

### Claim 14 (depends on 1)

The foam of claim 1 wherein the foam has a water uptake relative to void volume of at least 30%.

### Claim 15 (depends on 1)

The foam of claim 1 wherein the foam has a water uptake relative to void volume of at least 50%.

### Claim 16 (depends on 1)

The foam of claim 1 characterized in that when stems of cut flowers are inserted into the foam, the flowers do not wilt for at least 48 hours after insertion.

### Claim 17 (depends on 1)

The foam of claim 1 characterized in that the foam can be rehydrated with the addition of 10 ml of water.

### Claim 18 (depends on 1)

The foam of claim 1 characterized in that when stems of cut flowers are inserted into the foam, the flowers do not wilt for at least 132 hours with daily addition of 10 ml of water.

### Claim 19

A foam comprising (a) a polylactide polymer in the form of a star polymer having at least three arms, (b) a polysorbate surfactant in an amount no greater than 5 wt. % based on the total weight of the foam, and (c) a polyalkylene oxide block copolymer in an amount no greater than 7.5 wt. % based on the total weight of the foam, wherein the foam is an open cell foam having a density no greater than 0.06 g/cm3.

### Claim 20

A method of preparing a foam comprising:
(a) providing a foamable composition comprising a polylactide polymer in the form of a star polymer having at least three arms; and
(b) introducing carbon dioxide into the foamable composition to create an open cell foam having a density no greater than 0.1 g/cm3.

### Claim 21 (depends on 20)

The method of claim 20 wherein the foamable composition further comprises a polysorbate surfactant.

### Claim 22 (depends on 20)

The method of claim 20 wherein the foamable composition further comprises a polyalkylene oxide block copolymer surfactant.

### Claim 23 (depends on 20)

The method of claim 20 wherein the foamable composition further comprises an agent selected from the group consisting of ethyl acetate, isopropanol, ethyl lactate, diethyl ether, and combinations thereof.

### Claim 24 (depends on 20)

The method of claim 20 wherein the foamable composition further comprises a plasticizer.

### Claim 25 (depends on 20)

The method of claim 20 wherein the foamable composition further comprises a secondary foaming agent.