| 摘要 |
The surface (6) of a mold (1) for molding resins is made of a low-adhesion material (3) consisting of a solid solution, La-Y2O3, made from Y2O3 and another oxide, La2O3. La2O3 contains La having an ionic radius larger than that of Y3+ and therefore exhibits basicity stronger than that of Y2O3, while the low-adhesion material (3) has a prescribed La2O3 content based on the total amount of Y2O3 and La2O3. By virtue of these characteristics, the low-adhesion material (3) is reduced in the number of sites per unit area as compared with that of Y2O3 owing to the ionic radius and weakened in the binding strength for a basic substance owing to the basicity and maintains shape retentivity owing to the content. Thus, the surface (6) is made of a low-adhesion material (3) having lower adhesion than that of Y2O3 and excellent shape retentivity. The invention provides a low-adhesion material which has lower adhesion for a basic substance than that of Y2O3 and excellent shape retentivity and molds for molding resins which have excellent mold release properties and shape retentivity.
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