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AssigneeDow Global Technologies LLC
InventorsSandrine Burgun, Jonathan Kammerer, Chung P Park, William G Stobby, Suresh Subramonian
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A macmocellular foam is described having improved cell size and Fire-test-response Characteristics, among other features, which is obtained by selecting a particle size less than 1 micron for the flame retardant adjuvant. The inventors found that the amount of fire retardant adjuvant can be increased for a given foam cell size or the foam cell size can be increased for a given amount of fire retardant adjuvant, allowing the production of foams having exceptionally large, well-formed, cells that have excellent Fire-test-response Characteristics. The benefits are especially noteworthy in relation to thermoplastic foams and inorganic flame retardation adjuvants, due to the unexpected reduction in the nucleation effect of the adjuvant. The foams are useful for improving the acoustic performance of products that are required to meet certain Fire-test-response Characteristics. It may be used in automotive and other transportation devices, building and construction, household and garden appliances, power tool and appliance and electrical supply housing, connectors, and aircraft as acoustic systems for sound absorption and insulation.
A cellular polymer foam having an average cell size according to ASTM D3575 of at least 1.5 mm, the foam containing at least one flame retardant adjuvant, wherein the flame retardant adjuvant has an average particle size less than one micron.
The polymer foam of any one of the preceding claims further comprising a flame retardant.
The polymer foam of any one of the preceding claims having not more than 30 percent crosslinking after 10 days aging.
The polymer foam of any one of the preceding claims, wherein the polymer comprises at least 50 percent polypropylene.
The polymer foam of any one of the preceding claims, wherein the polymer foam has at least one surface, the at least one surface having defined therein a multiplicity of perforation channels extending from the at least one surface into the foam such that there is an average of at least one perforation channel per 10 square centimeters of the at least one surface.
The polymer foam of any of the preceding claims, wherein the polymer is a thermoplastic polymer.
A process for making cellular polymer foams comprising extruding at an elevated temperature a foamable gel from a first region having a first pressure into a second region having a second pressure less than the first pressure to allow expansion of the foamable gel, the foamable gel comprising at least one thermoplastic polymeric resin, at least one blowing agent, at least one flame retardant and at least one flame retardant adjuvant, wherein the solid particulate flame retardant adjuvant has a particle size less than 1 micron.
A method for increasing the maximum amount of solid particulate flame retardant adjuvant in cellular foams having a given average cell size according to ASTM D3575 of at least 1.5 mm comprising decreasing the average particle size of the solid particulate flame retardant adjuvant to smaller average particle size that is less than 1 micron.
Dependencies are inferred from the claim text.