| 摘要 |
Disclosed are an athletic-field marking powder and a chalk for non-slip grip which are harmless to humans and thus can be used safely. The athletic-field marking powder and the chalk mainly contain eggshell powder (P) in the form of porous fine particles having finely roughened surfaces. The eggshell powder (P) is formed by removing shell membranes from eggshells (E), and then pulverizing the eggshells (E) after drying. By effectively utilizing the eggshells, which have been conventionally treated as wastes, there can be provided the athletic-field marking powder and chalk for non-slip grip which are harmless to humans and safe. |
