Mould using for organic binder, molding sand composition and mould

Abstract

The invention provides an organic adhesive used in casting which can assure excellent casting intensity when phenolic aldehyde carbamate is cast, and can solve or reduce the sand-sticking problem that the sclerosis molding sand composition sticks on the surface of a mould. The organic adhesive of the invention is used in the gas sclerosis casting and the molding of the self- sclerosis casting of the phenolic aldehyde carbamate. The invention is characterized in that: the organic adhesive adopts a condensation product of unsaturated fatty acid with alcoholic hydroxyl, phenol formaldehyde resin, polyisocyanate compound, and organic solvent as the essential components.

Description

technical field [0001] The present invention relates to an organic binder for molds used for gas-hardening molds and self-hardening molds, and a molding sand composition and molds obtained by using the organic binder for molds, wherein the gas-hardening molds And no-bake molds are phenolic urethane-based gas-harden molds and no-bake molds for sand casting. Background technique [0002] Conventionally, as one of the representative organic molds used in sand casting, it is known to use phenolic resin and polyisocyanate compound as binder, and utilize the polyaddition reaction (urethanization reaction) between them to carry out molding. The phenolic urethane type cast. As such phenolic urethane molds, there are known mass-production type gas hardening molds produced by the cold box method without heating during molding, and non-mass-production type no-bake molds produced by the normal temperature no-bake method. [0003] Specifically, gas-hardening molds produced by the cold ...

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Problems solved by technology

[0004] However, the phenolic urethane mold molded from the molding sand composition obtained by using the above-mentioned organic binder, when molded, when the hardened mold is released from the metal mold as the forming mold, the hardened The molding sand covered with binder firmly adheres to the surface of the metal mold, and accumulates on the surface of the metal mold as the above-mentioned molding operations are repeated, resulting in molding defects such as cores, that is, the so-called "sticky sand". "question

[0005] Therefore, Japanese Patent Publication No. 48-32253 (Patent Document 1) clearly describes that in order to prevent the above-mentioned "sand sticking", the mold sand composition is mixed with fatty acid for molding, so that the hardened molding sand does not adhere to the mold surface. The manufacture method of mold, the present inventors have found through research that even if the above-mentioned fatty acid is used as the "anti-sticking sand agent", its effect is not sufficient, especially when the forming mold (metal mold) is used repeatedly, there is a problem of hardened molding sand. The problem of increased "sand sticking" on the surface of the molding mold. In addition, in terms of mold strength, especially when using a sand composition that has been manufactured for a long time to manufacture a mold, there are problems such as insufficient strength of the mold obtained.

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