Thermoplastic, moldable, non-exuding phase change materials
AssigneeUniversity of Dayton
InventorIval O. Salyer
Life of this patent
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Abstract
A thermoplastic, moldable, non-exuding phase change material in the form of a composite useful for thermal energy storage. The composite is preferably a solidified melt mixture of a polyolefin resin, and ethylene copolymer, silica particles and a fatty acid, fatty acid ester, primary alcohol or hydrocarbon phase change material. For a microwave heating capability, a microwave absorbing additive may be added as a fifth major ingredient. The composite can be formed into a variety of configurations such as pellets, sheets, rods, tubes, plugs for hollow core cement blocks, films, and fibers, all for thermal energy storage uses.
Claims20
A composite useful for thermal energy storage comprising a solidified melt mixture by weight percentage of about 15-22% of a polyolefin resin selected from the group consisting of uncrosslinked high density polyethylene and polypropylene, about 7-12% of an ethylene copolymer selected from the group consisting of an ethylene-vinyl acetate copolymer, an ethylene-methyl acrylate copolymer, and an ethylene-ethyl acrylate copolymer, about 7-16% silica particles having a surface area of from 50 to 500 square meters per gram and primary particle sizes of from 0.005 to 0.025 microns, and about 55-60% of a phase change material selected from the group consisting of crystalline alkyl hydrocarbons, crystalline fatty acids, crystalline fatty acid esters, crystalline 1-olefins, crystalline primary alcohols, crystalline alicyclic hydrocarbons, and crystalline aromatic hydrocarbons.
The method of preparing a composite useful for thermal energy storage comprising:
- melting an amount of a phase change material which comprises about 55-60 weight percentage of the composite, said phase change material being selected from the group consisting of crystalline alkyl hydrocarbons, crystalline fatty acids, crystalline fatty acid esters, crystalline 1-olefins, crystalline primary alcohols, crystalline alicyclic hydrocarbons, and crystalline aromatic hydrocarbons,
- stirring an amount of silica particles which comprises about 7-16 weight percentage of the composite into said melted phase change material until a stiff gel is formed, said silica particles having a surface area of from 50 to 500 square meters per gram and primary particle sizes of from 0.005 to 0.025 microns,
- adding to the stiff gel a mixture of an amount of polyolefin resin which comprises about 15-22 weight percentage of the composite and an amount of ethylene copolymer which comprises about 7-12 weight percentage of the composite, said polyolefin resin being selected from the group consisting of uncrosslinked high density polyethylene and polypropylene and said ethylene copolymer being selected from the group consisting of an ethylene-vinyl acetate copolymer, an ethylene-methyl acrylate copolymer, and an ethylene-ethyl acrylate copolymer,
- heating to melt said polyolefin resin and said ethylene copolymer,
- mixing vigorously to form a uniform viscous gel,
- cooling said viscous gel to solidify it into a moldable composite, and
- forming said moldable composite into a shape useful for thermal energy storage.
Dependencies are inferred from the claim text.