초록 ▼

Thermoplastic foams of polystyrene, for example, are prepared with a blowing agent which is a mixture of an organic plasticizing blowing agent, such as pentane, and an atmospheric gas, such as carbon dioxide. Typically, such foams prepared with organic blowing agent alone were aged prior to thermofo

Thermoplastic foams of polystyrene, for example, are prepared with a blowing agent which is a mixture of an organic plasticizing blowing agent, such as pentane, and an atmospheric gas, such as carbon dioxide. Typically, such foams prepared with organic blowing agent alone were aged prior to thermoforming the foam into articles. Foams prepared with the mixed blowing agent of this invention exhibit the advantage of reduced atmospheric emissions on aging.

대표청구항 ▼

A method for the formation of a thermoplastic foam which comprises introducing to a molten thermoplastic resin a blowing agent comprising at least one atmospheric gas and at least one volatile plasticizing blowing agent in amounts sufficient to plasticize said thermoplastic resin; extruding said the

A method for the formation of a thermoplastic foam which comprises introducing to a molten thermoplastic resin a blowing agent comprising at least one atmospheric gas and at least one volatile plasticizing blowing agent in amounts sufficient to plasticize said thermoplastic resin; extruding said thermoplastic in the form of a foam; and thermoforming said foam into articles; wherein the atmospheric gas is present in sufficient amounts to allow thermoforming immediately after the extrusion of the foam without substantial intermediate aging. A thermoplastic foam article containing in its porous interstices at least one atmospheric gas and at least one volatile plasticizing organic blowing agent, said organic blowing agent being present in an amount sufficient to allow thermoforming of said foam article without substantial aging as compared to thermoformed thermoplastic foam which does not contain said atmospheric gas within its porous interstices; said foam article emitting a reduced quantity of said organic blowing agent to the atmosphere during the formation of said foam article and thereafter thermoforming thereof.