塑料.聚氨酯原材料.异氰酸酯的测定

[中文适用范围]： 本国际标准规定了两种测定用于聚氨酯原料的芳香族异氰酸酯中异氰酸酯含量的方法。方法A主要适用于精制的甲苯二异氰酸酯（TDI）、亚甲基双-(4-苯基异氰酸酯)（MDI）及其预聚物。方法B适用于由甲苯二异氰酸酯、亚甲基双-(4-苯基异氰酸酯)和多亚甲基多苯基异氰酸酯衍生的精制、粗制或改性异氰酸酯。它也可用于甲苯二异氰酸酯、亚甲基双-(4-苯基异氰酸酯)和多亚甲基多苯基异氰酸酯的异构体混合物。如果采取预防措施验证适用性，其他芳香族异氰酸酯也可用此方法分析。该方法不适用于封端异氰酸酯。 [外文原描述]： ISO 14896:2009 specifies two methods for the measurement of the isocyanate content of aromatic isocyanates used as polyurethane raw materials. Method A is primarily applicable to refined toluene diisocyanate (TDI), methylene-bis-(4-phenylisocyanate) (MDI) and their prepolymers. Method B is applicable to refined, crude or modified isocyanates derived from toluene diisocyanate, methylene-bis-(4-phenylisocyanate) and polymethylene polyphenylisocyanate. It can also be used for isomer mixtures of toluene diisocyanate, methylene-bis-(4-phenylisocyanate) and polymethylene polyphenylisocyanate. Other aromatic isocyanates may be analysed by this method if precautions are taken to verify suitability. It is not applicable to blocked isocyanates.