| 摘要 |
PURPOSE:To obtain a white tube containing contrast medium which is never change on standing and excellent in fabricating property by mixing a white bismuth compound mainly containing bismuth oxide having a specified bismuth content and a specified grain size in the internal part of a tube wall consisting of thermoplastic resin. CONSTITUTION:In a white bismuth compound, bismuth content is reduced as the ratio of bismuth nitrate and bismuth sulfate to bismuth oxide is increased, but it is much more whitened. The white bismuth compound having a low bismuth content coagulates in the internal part of a fused resin to form large particles, which reduce the flowability of the fused resin, causing the aggravation in appearance of a molded product, but the use of a one having a certain grain size or less allows satisfactory fabricating property. Therefore, a white bismuth having a grain size substantially less than 20mum and a bismuth content of 70-85wt.% is used. In this case, when the bismuth content exceeds 85wt.%, the compound is not suitable for use because of its poor light resistance, and when the content is less than 70wt.%, molding effect is unpreferably reduced. |
