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AssigneeMatsushita Electric Industrial Co., Ltd.
InventorsToru Shiino, Kenichi Nobuta, Hiroshi Onishi
Estimating the term…
A solvent for polystyrene, having an excellent dissolving ability and chemical stability with no influence on the operating environment, is disclosed. A relatively simple recycling or reutilizing process of both the polystyrene foam and the solvent is also disclosed. The solvent comprises at least one member selected from the group consisting of such a glycol ether compound as diethylene glycol dimethyl ether, diethylene glycol diethyl ether or dipropylene glycol dimethyl ether, and such a fatty acid dialkyl ester compound as dimethyl succinate, dimethyl glutarate or dimethyl adipate. These compounds have a flash point of 100.degree. C. or higher, and can be made nonflammable by addition of water.
A method for recycling polystyrene foam comprising the steps of:
A method for recycling polystyrene foam comprising the steps of:
A method for recycling polystyrene foam comprising the steps of:
A method for recycling polystyrene foam comprising the steps of:
A method for reducing volume of polystyrene foam comprising the step of:
Dependencies are inferred from the claim text.
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Without chemical reactions: using selective solvents for polymer components
Characterised by the chemical constitution of the organic liquid: oxygen containing compounds
Homopolymers or copolymers of styrene: polystyrene
Reuse, recycling or recovery technologies: plastics recycling; Rubber recycling
Term ended 16 Apr 2016 (estimated)
USPTO file history isn’t available for this patent, so only indexed dates are shown.
1. Field of the Invention
The present invention relates to a solvent enabling reduction in the volume and recycling of polystyrene foam or expanded polystyrene, and, in particular, to a method for recycling polystyrene foam materials.
2. Description of the Prior Art
The glycol ether compounds represented by the above-mentioned formula (1), wherein the alkyl groups represented by C.sub.m H.sub.2m+1 and C.sub.n H.sub.2n+1 are any of methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group and tert-butyl group, can be exemplified as diethylene glycol monoalkyl ether, dipropylene glycol monoalkyl ether, diethylene glycol dialkyl ether and dipropylene glycol dialkyl ether. In the above-mentioned dialkyl ether compounds, the two alkyl groups may be the same or may be different from each other.
Since the ability of the solvent to dissolve polystyrene increases with increase in the Concentration of these glycol ether compounds in the solvent, it is most desirable to configure the solvent only with the glycol ether compounds represented by the above-mentioned formula (1).
On the other hand, the fatty acid dialkyl ester compounds represented by the above-mentioned formula (2), wherein the alkyl groups represented by R.sub.1 and R.sub.2 are any of methyl group, ethyl group, propyl group, iso-propyl group and butyl group, and n indicating the number of the methylene group is in a range of 0-4, can be exemplified as dialkyl esters of oxalic acid, malonic acid, succinic acid, glutaric acid and adipic acid. In the above-mentioned dialkyl ester compounds, the two alkyl groups may be the same or may be different from each other.