| 摘要 |
PURPOSE:To provide a chalk which can be written on the surfaces of various materials and whose handwriting can be readily erased by rubbing with paper or cloth, by combining an animal or vegetable wax with a nonionic surfactant, adding a pigment thereto and molding the mixture. CONSTITUTION:A mineral wax (e.g. paraffin) and optionally PP resin are added to an animal or vegetable wax (e.g. rice bran wax). The mixture is molten by heating and mixed with a nonionic surfactant (e.g. polyoxyethylene spermoleylstearyl ether), and the resulting mixture is cooled to 55-60 deg.C. An org. pigment and precipitated CaCO3 are added to the mixture. The resulting mixture is melt- kneaded at 80-90 deg.C and cast into the desired shape.
|
