# US 12,180,326 B2 · Low density polyurethane foam systems with high split tear

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- Number: US 12,180,326 B2
- Document ID: US12180326B2
- Status: Granted
- Kind: B2
- Application number: 17/609,607
- Filed: 2020-04-29
- Published: 2022-07-21
- Granted: 2024-12-31
- Earliest claimed: 2019-05-16
- Assignees: BASF SE
- Applicants: BASF SE
- Inventors: Cai An Wang; Chang Xi Li; Ren Zheng Zhang
- Web page: https://patentgrep.com/patent/US12180326B2

## CPC

- C08G 18/4854: {Polyethers containing oxyalkylene groups having four carbon atoms in the alkylene group}
- C08G 18/10: Prepolymer processes involving reaction of isocyanates or isothiocyanates with compounds having active hydrogen in a first reaction step
- C08G 18/3206: {aliphatic}
- C08G 18/3275: {containing two hydroxy groups}
- C08G 18/66: Compounds of groups C08G18/42, C08G18/48, or C08G18/52
- C08G 18/6674: {with compounds of group C08G18/3203}
- C08G 18/6688: {with compounds of group C08G18/3271}
- C08J 9/125: {Water, e.g. hydrated salts}
- C08J 9/228: Forming foamed products
- C08J 9/32: from compositions containing microballoons, e.g. syntactic foams
- C08G 2110/0066: ≥ 150kg/m3
- C08J 2203/10: Water or water-releasing compounds
- C08J 2203/22: Expandable microspheres, e.g. Expancel®
- C08J 2375/08: from polyethers
- C08G: MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- 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

Described herein is a polyurethane foam produced in a “one shot process” that has low density, is semi-hard, and displays a high rebound value all while providing superior split tear performance. The polyurethane foam can be used in a “one shot process” to produce a shoe sole, a mid-sole or an insole for a shoe. The shoe sole may be used for forming an outer sole of a sandal type shoe, a midsole of an athletic type shoe, or an insole for insertion into any type of shoe.

## Claims

### Claim 1

A polyurethane foam having a density of 150 to 400 g/L measured according to DIN EN ISO 845, wherein the polyurethane foam is formed by reacting a mixture consisting of:
80 to 50 weight percent (wt. %) of a polyol formulation and 20 to 50 wt. % of an isocyanate prepolymer, wherein the wt. % is based on the total weight of the mixture;
wherein the polyol formulation comprises 90 to 98 wt. % of a polytetramethylene ether glycol (PTMEG) with a weight average molecular weight (MWw) of 1800 to 2100, 0.1 to 6 wt. % of expandable microspheres and 0.5 to 3 wt. % of water, wherein the wt. % values for the polyol formulation are based on the total weight of the polyol formulation.

### Claim 2 (depends on 1)

The polyurethane foam of claim 1, further comprising a catalyst, a surfactant, a crosslinking agent, and other optional additives as ingredients in the polyol formulation, wherein the catalyst, the surfactant, the crosslinking agent, and other optional additives together bring the wt. % of the polyol formulation to 100 wt. %.

### Claim 3 (depends on 1)

The polyurethane foam of claim 1, wherein the isocyanate pre-polymer includes:
40 to 70 wt. % of an isocyanate component having at least 92 wt. % of 4,4′-diphenylmethane diisocyanate; and 30 to 60 wt. % of the PTMEG, based on the total weight of the isocyanate pre-polymer, wherein the NCO value of the isocyanate prepolymer is 15 to 22.

### Claim 4 (depends on 1)

The polyurethane foam of claim 1, wherein the polyol formulation has a water content of 0.8 to 2 wt. % based on the total weight of the polyol formulation.

### Claim 5 (depends on 1)

The polyurethane foam of claim 1, wherein the polyol formulation has an expandable microspheres content of 0.5 to 5 wt. % based on the total weight of the polyol formulation.

### Claim 6 (depends on 1)

The polyurethane foam of claim 1, wherein the polyurethane elastomer foam has a vertical rebound of 55% to 65% measured according to ASTM D2632.

### Claim 7 (depends on 1)

The polyurethane foam of claim 1, wherein the polyurethane elastomer foam has an Asker C hardness of 25 to 70 measured according to ASTM D2240.

### Claim 8 (depends on 1)

A shoe sole, a mid-sole or an insole formed from the polyurethane foam of claim 1.

### Claim 9 (depends on 1)

A method of forming a polyurethane foam according to claim 1, comprising
i) preparing a polyol formulation by admixing at room temperature and melting PTMEG at 70° C. overnight and then keeping it at 40 to 50° C. for a better handling and dosing together with other components,
ii) heating the polyol formulation to a temperature of 40 to 45° C. inside a stirred reactor tank of a polyurethane foam machine,
iii) heating an isocyanate prepolymer to a temperature of 30 to 45° C. inside an isocyanate tank of a polyurethane foam machine,
iv) admixing the isocyanate pre-polymer with the polyol formulation at atmospheric pressure and pouring the mixture using the polyurethane foam machine into a heated mold with desired shape, and
v) closing the mold, allowing the reactants to fill the mold and react for a given demolding time to form a polyurethane foam.

### Claim 10 (depends on 9)

The method of claim 9, wherein the polyurethane forming composition has 50 to 80 weight percent of a polyol formulation and 20 to 50 wt. % of an isocyanate prepolymer, wherein the wt. % is based on the total weight of the polyurethane forming composition.

### Claim 11 (depends on 9)

The method of claim 9, wherein the heated mold has a temperature of 50 to 60° C. and the demolding time is from 5 to 15 min.

### Claim 12 (depends on 1)

The polyurethane foam of claim 1, wherein the polyol formulation has a water content of 1.4 to 2 wt. % based on the total weight of the polyol formulation.

### Claim 13 (depends on 1)

The polyurethane foam of claim 1, wherein the polyol formulation has an expandable microspheres content of 1 to 5 wt. % based on the total weight of the polyol formulation.

### Claim 14 (depends on 1)

The polyurethane foam of claim 1, wherein the polyurethane elastomer foam has an Asker C hardness of 30 to 55 measured according to ASTM D2240.

### Claim 15 (depends on 1)

The polyurethane foam of claim 1, wherein the polyurethane elastomer foam has an Asker C hardness of 35 to 55 measured according to ASTM D2240.