News Details
Beta-hydroxyalkylamide coating crosslinking agent
2017-8-31 23:01:26
Beta-hydroxyalkylamide coating crosslinking agent
Diethyltoluenediamine Raw material ：
TDA industrial, Sichuan production
Ethylene (Et) polymer grade, Shanghai production
TEA industrial imports
Domestic at present mainly use TGIC (three glycidyl different melamine urea acid ester) as crosslinking agent, weather resistance type powder coating because TGIC has certain toxicity, has banned the use of in places such as North America and Japan, and the main alternatives are beta hydroxy alkyl amides crosslinking agent (beta HAA).
Beta hydroxy alkyl amide type of crosslinking agent is a white crystalline compound, with four functional groups compared with TGIC with low toxicity, relatively low cost, low crosslinking temperature and storage stability is good wait for an advantage.
But because its functional group is hydroxyl, it is crosslinked through the carboxyl reaction of the carboxyl polyester resin, which can produce water molecules during the reaction process. TGIC epoxy group and carboxyl reaction belongs to addition reaction, so the mechanism of crosslinking reaction, such as direct use usually TGIC type with the weather resistance of polyester resin and beta hydroxy alkyl amide crosslinking agent reaction can produce pinhole, heated easy yellowing and other shortcomings in the crosslinking.
In this article, through the development of new formulation and production process, adjust the molecular structure of resin products, the introduction of different reactive carboxyl and reasonable process, suitable for beta hydroxy alkyl amide was synthesized crosslinking agent use end carboxyl polyester resin. Synthetic end carboxyl polyester resin is especially suitable for and beta hydroxy alkyl amides crosslinking agent made from powder coating, powder coating has good yellowing resistance, coating is not easy to appear the pinhole, good weather resistance, etc.
Test of raw materials: purified terephthalic acid (pta), isophthalic acid, trimethylolpropane, neopentyl glycol and adipic acid, trimellitic anhydride, ethylene glycol, 2 - methyl - 1, 3 - propanediol, cyclohexane two methanol, cyclohexane, F4100 diformate (methyl tin oxide), T - 105 (beta hydroxy alkyl amide), titanium dioxide, barium sulfate, flow ping agent (PV88), benzoin, are all industrial products.
Main test equipment: self-designed 50 L small stainless steel reaction kettle; Φ 30 small milling equipment such as twin screw extruder; Small electrostatic spraying equipment; Impact tester and other coating performance testing equipment.
The synthesis process of polyester resins: the mixture of polyols and polyacid and catalyst (F4100) were added to 50 L reaction caldron according to the formula, stirring evenly. Under nitrogen protection, heats up to 180 ~ 250 ℃, the vacuum after the condensation by acid value, hydroxyl value, viscosity and relative molecular mass and its distribution of products that meet the requirements.
Chinese name: Diethyl toluene diamine(DETDA)Diethyltoluenediamine Raw material ：
TDA industrial, Sichuan production
Ethylene (Et) polymer grade, Shanghai production
TEA industrial imports
A reagent grade additives
The preparation of powder coating and coating: according to the basic formula, preparation of powder coating process is: the ingredients - premixed - extrusion to tablet to crushing, sieving, products will be the preparation of powder coatings with electrostatic spraying and according to certain crosslinking conditions are crosslinked coating, paint and coating performance testing.
The relationship between Tg and monomer structure of polyester resin: the Tg of resin depends on its composition and structure, such as the nature of the main chain and the existence of the branched chain. Directly from the monomer, the different monomers and their ratio have a great influence on the Tg of resin. The Tg of resin has great influence on the storage stability of powder coatings.
The polyol was used in the new pentanediol, and the polyacid was phthalic acid and terephthalic acid. With the increase in the dosage of phthalates, the Tg of resin decreased.
The polyol is used in the new pentadiol, polyacid is terephthalic acid and adipic acid. In general, the main chain of the molecule is composed of the saturated single bond, because the molecule is easy to rotate around the single bond, the chain segment activity increases, and the Tg decreases.
If the rigid groups such as phenyl, diphenyl or heterocyclic compound are introduced into the main chain, the rotation of single bonds will be impeded, and the Tg will be improved. The existence of the branched chain has some influence on Tg, and the large branched chain groups produce spatial obstacles, which hinder the rotation of single bonds, thus improving Tg. The increase of Tg can also be caused by the interaction of the polar groups with their interaction forces. Therefore, the Tg of polyester resin can be regulated by the selection of the monomer and the proportion of the change component.
Copyright: Zhang Jia Gang YaRui Chemical co.,Ltd
Copyright: Zhang Jia Gang YaRui Chemical co.,Ltd
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