GB/T 12009.5-2016 in English

《GB/T 12009.5-2016塑料 聚氨酯生产用芳香族异氰酸酯 第5部分：酸度的测定》由TC15（全国塑料标准化技术委员会）归口，TC15SC8（全国塑料标准化技术委员会聚氨酯塑料分会）执行，主管部门为中国石油和化学工业联合会。

Scope

This part of GB/T 12009 specifies the method for the determination of acidity in aromatic isocyanate for polyurethane production by potentiometric titration. This section applies to the determination of the acidity of aromatic isocyanates and their prepolymers of polyurethane raw materials. Method A is suitable for crude or modified diphenylmethane diisocyanate, polymethylene polyphenylisocyanate and toluene diisocyanate products with medium/high acidity values (>100 μg/g). Method B is suitable for low acidity value (<100 μg/g) refined, crude or modified diphenylmethane diisocyanate, polymethylene polyphenylisocyanate and toluene diisocyanate. These methods are also applicable to mixtures of isomers of toluene diisocyanate, diphenylmethane diisocyanate and polymethylene polyphenylisocyanate. Other isocyanates can also be used in this way if it proves suitable.