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 a liquid petroleum gas. The microspheres are expanded by heat to as much as 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 energy-absorbing miniature springs dispersed throughout the body.

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.

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.

Abstract: A technique for enhancing the mechanical, thermal or other properties of an open-cell synthetic plastic foam body by injecting filler particles into the cells thereof. The filler particles, which may take the form of micro-spheres of glass, metal powers or other additives, depending on the property to be enhanced, are fed into a pressurized stream of air which is projected at high velocity to fluidize the particles. The stream is directed toward the surface of the body to cause the particles carried thereby to impregnate the cells.

Abstract: A modified low-density flexible polyurethane foam product having a relatively high degree of firmness as well as commercially acceptable dielectric heat sealing characteristics. The product formulation includes an intermediate constituted by a mixture of polyol and a polymer/polyol in a ratio imparting to the product a predetermined degree of firmness, and a thermoplastic additive whose dielectric loss index is greater than the loss index of polyurethane foam to impart to the product an acceptable dielectric heating response in a high frequency electric field. This response is enhanced by acrylonitrile/styrene components included in the polymer/polyol.

Abstract: A modified low-density flexible polyurethane foam product having a relatively high degree of firmness as well as commercially acceptable dielectric heat sealing characteristics. The product formulation includes an intermediate constituted by a mixture of polyol and a polymer/polyol in a ratio imparting to the product a predetermined degree of firmness, and a thermoplastic additive whose dielectric loss index is greater than the loss index of polyurethane foam to impart to the product an acceptable dielectric heating response in a high frequency electric field. This response is enhanced by a styrene component included in the polymer/polyol.

Abstract: A modified, flexible polyurethane foam product which incorporates a three-dimensional skeletal network of a thermoplastic additive whose dielectric loss index is greater than the loss index of polyurethane foam to impart to the product an acceptable dielectric heating response in a high-frequency electric field. The additive in particulate form is introduced into the polyurethane foam-forming reaction mixture, the additive having a gell point which is lower than the temperature level of the exothermic reaction which takes place when the mixture is caused to foam and expand. The additive is further characterized by a low order of viscosity whereby when rendered molten by the exothermic reaction, the particles are extruded by the expanding urethane mass to create tentacles that interlace the cellular urethane structure to form the skeletal network.