Polyolefin foams made with isopentane-based blowing agents
AssigneePactiv Corporation
InventorsY. Paul Handa, Jiayan Gu
Life of this patent
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Abstract
A blowing agent blend for making polyolefin foams comprising isopentane and at least one co-blowing agent The co-blowing agent is either a physical co-blowing agent having a boiling point less than 28° C., or a chemical co-blowing agent, or combinations thereof The blowing agent blend comprises less than about 99 mol % isopentane.
Claims46
A blowing agent blend for making polyolefin foams comprising isopentane and at least one co-blowing agent, the co-blowing agent being either a physical co-blowing agent having a boiling point less than 28° C., or a chemical co-blowing agent, or combinations thereof, and wherein the blowing agent blend comprises less than about 99 mol % isopentane.
A polyolefin foam structure prepared by the process comprising:
- melting a thermoplastic polyolefin polymer,
- dissolving an effective amount of a blowing agent blend in the polyolefin polymer, the blowing agent blend comprising less than about 99 mol % isopentane and at least one co-blowing agent, the co-blowing agent being either a physical co-blowing agent having a boiling point less than 28° C., or a chemical co-blowing agent, or combinations thereof,
- forming an extrudate,
- transferring the extrudate to an expansion zone, and
- permitting the extrudate to expand in the expansion zone to produce the polyolefin foam structure, the polyolefin foam structure being a substantially closed-cell and dimensionally-stable structure.
A process for making a polyolefin foam structure comprising:
- melting a thermoplastic polyolefin polymer,
- dissolving an effective amount of a blowing agent blend in the polyolefin polymer, the blowing agent blend comprising less than about 99 mol % isopentane and at least one co-blowing agent, the co-blowing agent being either a physical co-blowing agent having a boiling point less than 28° C., or a chemical co-blowing agent, or combinations thereof,
- forming an extrudate,
- transferring the extrudate to an expansion zone, and
- permitting the extrudate to expand in the expansion zone to produce the polyolefin foam structure.
A blowing agent blend for foaming low density polyethylene foam consisting essentially of isopentane and at least one co-blowing agent, the co-blowing agent being either a physical co-blowing agent having a boiling point less than 28° C., or a chemical co-blowing agent, or combinations thereof, and wherein the blowing agent blend includes from about 10 to about 99 mol % isopentane and the remainder consists essentially of the co-blowing agent.
A process for making a low density polyethylene foam structure prepared by the process comprising:
- melting a low density polyethylene polymer;
- dissolving an effective amount of a blowing agent blend in the low density polyethylene polymer, the blowing agent blend comprising from about 10 to about 99 mol % isopentane and at least one co-blowing agent, the co-blowing agent being either a physical co-blowing agent having a boiling point less than 28° C., or a chemical co-blowing agent, or combinations thereof,
- forming an extrudate,
- transferring the extrudate to an expansion zone, and
- permitting the extrudate to expand in the expansion zone to produce the low density polyethylene structure.
Dependencies are inferred from the claim text.