| 摘要 |
PROBLEM TO BE SOLVED: To obtain a coating material having excellent thixotropy and tightly adhering to the surfaces of various substrates by using fine waste sand having a specified or smaller particle diameter and obtained in recovering foundry sand from used sand molds, as an inorganic aggregate of a water-based coating material comprising a cemental setting material, an acrylic resin and the inorganic aggregate. SOLUTION: The inorganic aggregate used is fine waste sand having a means particle diameter of at most 100μm and obtained in the recovery, regeneration, and classification of casting sand from used sand molds or of a mixture thereof with another inorganic aggregate. Especially, fine waste sand obtained from the roasting of the recovered foundry sand, from the grinding subsequent the roasting, and from the classification subsequent to the roasting or the grinding is desirable. The source of the fine waste sand is particularly desirably and used green sand mold or a used shell mold. The content of the fine waste sand is desirably 18-89 wt.% based on the weight of the solids of a coating material. The mixing ratio of the fine waste sand to the other inorganic aggregate is desirably 90:10 to 20:80 by weight.
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