Low density foamed polymers
First Claim
Patent Images
1. A foamable thermoplastic polymer melt comprising:
- a thermoplastic polymer;
a nucleating agent composition present in an amount sufficient to form a large number of very small cells and chemically inert with respect to the thermoplastic polymer; and
a blowing agent that is soluble in the polymer melt and present in an amount sufficient to generate foam but less than an amount that would excessively plasticize the polymer composition, and inert with respect to the thermoplastic polymer and the nucleating agent.
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Abstract
A foamed polymer melt including a thermoplastic polymer or polymer blend; a nucleating agent present in an amount sufficient to form a large number of very small cells, specifically cells having a diameter of no greater than about 150 μm, and chemically inert with respect to the thermoplastic polymer or polymer blend; and a blowing agent present in an amount sufficient to effectuate foaming but less than an amount that would plasticize the polymer composition, and inert with respect to the thermoplastic polymer or polymer blend and the nucleating agent is provided.
95 Citations
48 Claims
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1. A foamable thermoplastic polymer melt comprising:
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a thermoplastic polymer;
a nucleating agent composition present in an amount sufficient to form a large number of very small cells and chemically inert with respect to the thermoplastic polymer; and
a blowing agent that is soluble in the polymer melt and present in an amount sufficient to generate foam but less than an amount that would excessively plasticize the polymer composition, and inert with respect to the thermoplastic polymer and the nucleating agent. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 45, 46)
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26. A method of forming a foamed polymer, the method comprising:
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extruding a molten thermoplastic polymer containing an inert nucleating agent at or above the melt temperature of the thermoplastic polymer, and injecting a blowing agent into the extruded melt.
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- 27. A method of forming a foamed thermoplastic polymer comprising extruding a molten thermoplastic polymer blend in the presence of a blowing agent and fluorocarbon particles that are no larger than micro-sized.
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29. A method of forming a polymer that favorably forms foamed shaped items, the method comprising:
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extruding a composition of a thermoplastic resin, a nucleating agent in an amount of between about 0.1 and 10 percent by weight of the composition and being insoluble and chemically inert with respect to the thermoplastic resin, and a blowing agent in an amount of no more than about 10% by weight, the blowing agent being soluble in the thermoplastic resin, chemically inert with respect to the thermoplastic polymer and the nucleating agent, and normally in the gaseous state at atmospheric pressure; and
while carrying out the extrusion at a pressure drop sufficient to form cells on individual particles of the nucleating agent as the composition extrudes. - View Dependent Claims (30, 31, 32, 33)
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34. A foamed polymer composition comprising:
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at least about 90 percent by weight of a thermoplastic polymer blend, between about 0.1 and 10% by weight of a nucleating agent, and at least about 0.05% of a blowing agent. - View Dependent Claims (35, 36, 37, 38)
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39. A method of forming shaped foamed items, the method comprising:
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extruding a composition of a thermoplastic resin, a nucleating agent in an amount of between about 0.1 and 10 percent by weight of the composition and being insoluble and chemically inert with respect to the thermoplastic resin, and a blowing agent in an amount of no more than about 10% by weight, the blowing agent being soluble in the thermoplastic resin, chemically inert with respect to the thermoplastic polymer and the nucleating agent, and normally in the gaseous state at atmospheric pressure;
while carrying out the extrusion at a pressure drop sufficient to form cells on individual particles of the nucleating agent as the composition extrudes; and
solidifying the resulting foam. - View Dependent Claims (40, 41, 42, 43, 44, 47, 48)
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Specification