摘要 |
Fluorescent or phosphorescent pigments based on zinc sulphides, zinc and cadmium sulphides, and alkaline earth sulphides are coated with glass by mixing a finely comminuted glass exempt from heavy metals and having a melting or softening point less than 800 DEG C with the powdered pigment in a ratio of 100:1 to 1:1, preferably 5:1 to 2:1, and then heating the mixture to a temperature at which the glass softens to such an extent that it surrounds the pigment. The mixture can be melted in blocks which are then size reduced to granular form. Mouldings which can be heated to the softening point can also be made from the mixture in paste form. The bodies consisting of pigments coated with glass or having a coating of pigments coated in glass, are embedded in a matrix and then applied as a coating to a substrate. For the manufacture of concrete stones, concrete mouldings or similar, cement and white, pure quartz gravel or quartz sand and/or quartz glass are used as the matrix. For the manufacture of concrete building components, the glass pigment-containing bodies are applied to an adhesive film coated with a retarder which is then placed in the mould. The matrix is then applied and the facing layer so formed is then filled with ordinary concrete. Other suitable matrices are thermosetting plastics, thermoplastics and elastomers. The glass bodies containing pigments can also be melted directly on to a substrate. |