Modified low-density polyurethane foam body
First Claim
1. A low-density, open-cell polyurethane body modified to impart resilience and enhanced shock-absorbing properties thereto, the cells having entrapped therein expanded microspheres of a vinylidene chloride polymer each defined by a soft, gas proof polymeric shell enclosing a compressible isobutane gas whereby the expanded microspheres act as miniature springs which are dispersed throughout the body which when the body is subjected to pressure and is deformed thereby are compressed and when the pressure is released cause the body to recover its normal form.
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Abstract
A low-density, open-cell flexible polyurethane foam body that is modified to impart resilience and enhanced shock-absorbency properties thereto. Modification is effected by implanting in the open cells of the body expandable microspheres having particle sizes in the micron range, each microsphere being formed by a gas proof polymeric shell encapsulating a drop of liquid isobutane. The microspheres are expanded by heat to more than fifty times their initial volume and are entrapped in the open cells of the body. The expanded microspheres are constituted by a soft polymeric shell enclosing a compressible gas, the expanded microspheres behaving as miniature springs dispersed throughout the body.
23 Citations
7 Claims
- 1. A low-density, open-cell polyurethane body modified to impart resilience and enhanced shock-absorbing properties thereto, the cells having entrapped therein expanded microspheres of a vinylidene chloride polymer each defined by a soft, gas proof polymeric shell enclosing a compressible isobutane gas whereby the expanded microspheres act as miniature springs which are dispersed throughout the body which when the body is subjected to pressure and is deformed thereby are compressed and when the pressure is released cause the body to recover its normal form.
Specification