CAS：935-79-5| The Application of THPA in coating

Product Name/English Name：cis-1,2,3,6-Tetrahydrophthalic anhydride
English abbreviation：THPA
CAS：935-79-5
Molecular Formula：    C8H8O3
Article No.：S1112
Structural Formula：

Product Introduction
THPA is an important chemical product, mainly used as a curing agent for epoxy resins, a modifier for unsaturated polyester resins and alkyd resins, and an important intermediate in the synthesis of pesticides and pharmaceuticals. In addition, THPA can also be applied to coating.

Application of THPA
In recent years, global warming, ozone layer destruction, acid rain and other environmental pollution have become international issues. Among them, the emission of organic solvents (VOCs) into the atmosphere is a significant issue. Therefore, in the context of strengthened regulation of VOC emissions, the coating industry is promoting VOC removal. In the process of promoting VOC removal, the market has begun to widely use powder coatings that are completely VOC free, do not require exhaust treatment or wastewater treatment, and can be recycled and reused. Powder coatings mainly use acrylic resin, polyester resin, or epoxy resin as raw materials. However, the weather resistance of the cured film formed by the powder coating produced using the above raw materials is not sufficient. Therefore, the CN106232751B patent has developed a powder coating and coating article, which contains fluorine resin A, metal element B, light stabilizer C, and polymerization inhibitor D.
Among them:
Fluorine resin (A) is a homopolymer or copolymer based on fluoroolefin units, with a glass transition temperature of over 30℃ and an average molecular weight of 3000-5000. As an anhydride, it can be succinic anhydride, glutaric anhydride, itaconic anhydride, 1,2-cyclohexanedioic anhydride , cis-4-cyclohexene-1,2-dicarboxylic anhydride, phthalic anhydride, 4-methylhexahydrophthalic anhydride, 1,8-naphthalene dicarboxylic anhydride, maleic anhydride, etc.
Light stabilizer C is a hindered amine based light stabilizer with a molecular weight of 300-5000 and a melting point of 50-250℃.
Inhibitor D is hydroquinone.
The powder coating of the present invention can suppress the increase in molecular weight of fluorine resin during the manufacturing of the powder coating, and the formed curing film has excellent surface quality, which can prevent appearance abnormalities such as orange peel.

References
CN106232751B Powder coatings and coated items.