| 摘要 |
PURPOSE:To prevent foaming due to moisture absorption of the sheet upon heating vacuum molding by adding the composition of thermoplastic synthetic resin sheet for vacuum molding with calcium oxide. CONSTITUTION:The composition of sheet is added with calcium oxide. Upon absorbing moisture, calcium oxide reacts with water and is changed into calcium hydroxide. CaO+H2O Ca(OH)2. The decomposition temperature of calcium hydroxide is higher than 500 deg.C, therefore, it is not decomposed at a heating temperature 130-200 deg.C upon the vacuum molding. Accordingly, foaming phenomenon due to moisture will never be generated. Calcium hydroxide has forming preventing effect regardless of the kind thereof, however, conjugated inorganic ceramics, obtained by reaction calcining of limestone, is preferable. |
