| 摘要 |
<p>Problem Provided are a projection blackboard having both of an excellent blackboard function and an excellent screen function, and a process for producing the same. Solving means The surface enamel layer that is an outermost layer of the enamel layers is formed by using a enameling upper glaze wherein at least titanium oxide coated particles, or a titanium oxide glaze together therewith is blended into a transparent mat glaze, so as to render the layer an enamel layer having a predetermined color tone, a surface characteristic that the Rz is from 5 to 25 µm and a reflective characteristic that the peak gain is 0.28 or more, or having these properties and a glossiness Gs (75°) of 1 to 30%. This makes it possible to produce a blackboard excellent in both of blackboard function and screen function. The titanium oxide coated particles are preferably particles wherein surfaces of mica particles are coated with titanium oxide. The metallic substrate is preferably a cold-rolled steel sheet, an aluminum plated steel sheet, or a Zn-A1 alloy plated steel sheet.</p> |
