| 摘要 |
PURPOSE:To obtain the titled composition having excellent melt-spinnability, strength and water-resistance and free from generation of a fluorine compound in melting, by using SiO2, Al2O3, MgO and B2O3 as essential components at specific ratios. CONSTITUTION:The objective composition contains 50-60wt% SiO2, 25-35wt% Al2O3, 8-15wt% MgO and 2-6.5wt% B2O3 as essential components and, if necessary, contains <=2wt% CaO and <=1wt% each of at least one of R2O, Fe2O3 and TiO2.
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