This standard specifies determination method of formaldehyde content of waterborne coatings.
This standard is applicable to testing of waterborne coatings with formaldehyde content not less than 5mg/kg and their raw materials.
2 Normative References
The following normative documents contain provisions which, through reference in this standard, constitute provisions of this standard. For dated reference, subsequent amendments (excluding corrections), or revisions, of any of these publications do not apply to this standard. However, parties to agreements based on this standard are encouraged to investigate the possibility of applying the most recent editions of the normative documents indicated below. For undated references, the latest edition of the normative document referred to applies.
GB/T 601 Chemical Reagent - Preparations of Standard Volumetric Solutions
GB/T 3186 Paints Varnishes and Raw Materials for Paints and Varnishes - Sampling (GB/T 3186-2006, ISO 15528: 2000, IDT)
GB/T 6682 Water for Analytical Laboratory Use-Specification and Test Methods(GB/T 6682-2008, ISO 3696: 1987, MOD)
3 Principle
Formaldehyde is separated from the sample through distillation. In the acetic acid-ammonium acetate buffer solution (pH=6), formaldehyde and acetylacetone in the distillate, once heated, will react and form a stable yellow complex, which is cooled and then subjected to absorbance testing at a wavelength of 412nm. Formaldehyde content of the specimen is calculated according to the standard work curve.
