酚醛树脂、氨基树脂和缩合树脂.游离甲醛含量的测定

[中文适用范围]： 本国际标准规定了测定下列物质中游离甲醛含量的三种方法： a) 酚醛树脂，通过水溶液或有机溶液中的电位滴定法（盐酸羟胺法）。 该方法适用于游离甲醛含量≤15%（质量）的树脂。 对于游离甲醛含量在 15% 至 30% 质量之间的情况，可能需要相应调整所用标准容量溶液的浓度。 b) 氨基树脂和呋喃树脂（亚硫酸盐程序）。 该方法适用于尿素、三聚氰胺与甲醛缩聚得到的树脂以及糠醇与甲醛缩聚得到的呋喃树脂，无需进一步改性。 c)缩合树脂(KCN程序)，包括尿素树脂、呋喃树脂、三聚氰胺树脂和酚醛树脂，以及这些树脂的组合和改性。 本国际标准的目的是建立公认的和有用的确定程序（例如，为了检查是否遵守了有关处理危险工作场所材料的官方规定）。 就这一点而言，尽可能包括所有含甲醛树脂。 使用本国际标准测定的甲醛缩合树脂中的游离甲醛含量代表测定时的实际含量。 该值与加工过程中或加工后的游离甲醛含量没有定量关系。 [外文原描述]： ISO 11402:2004 specifies three methods for determining the free-formaldehyde content in the following: Phenolic resins, by potentiometric titration in aqueous or organic solution (hydroxylamine hydrochloride procedure). The method is applicable to resins with free-formaldehyde contents up to and including 15 % by mass. For free-formaldehyde contents between 15 % by mass and 30 % by mass, it may be necessary to adjust the concentrations of the standard volumetric solutions used accordingly. Amino resins and furan resins (sulfite procedure). The method is applicable to resins resulting from the polycondensation of urea and melamine with formaldehyde and to furan resins resulting from the polycondensation of furfuryl alcohol with formaldehyde without further modification. Condensation resins (KCN procedure), including urea resins, furan resins, melamine resins and phenolic resins, as well as combinations and modifications of these resins. The purpose of this International Standard is to establish recognized and useful determination procedures (for instance in order to check whether official regulations on the handling of hazardous workplace materials are observed). The free-formaldehyde content determined in formaldehyde condensation resins using this International Standard represents the actual content at the time of the determination. The value bears no quantitative relationship to the free-formaldehyde content during or after processing.