| 摘要 |
PURPOSE:To reversibly obtain a transparent and opaque state change in conformity with heating and cooling by forming a thermal sheet by the coating with a reversible thermal material in a film form to reversibly generate a transparent and opaque state change by heating or cooling. CONSTITUTION:A reversible thermal material is applied in a film form to form a thermal sheet and a transparent and opaque state change is reversibly generated by heating or cooling the thermal sheet. Herein, the reversible thermal material is composed of a mixture of an org. polymer and a liquid crystal material and the liquid crystal material is a nematic liquid crystal having phase transition temp. at the normal temp. or higher. By this method, a sheet extremely high in opacity at the normal temp. can be obtained. After phase transition is generated at high temp., extremely high transparency is obtained because the difference of a refractive index with a resin is extremely low and, as a result, a transparent and opaque state change extremely high in contrast is obtained. |
