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An acid anhydride epoxy paint crosslinking agent
2017-8-7 23:35:52
An acid anhydride epoxy paint crosslinking agent
Diethyltoluenediamine Raw material ：
TDA industrial, Sichuan production
Ethylene (Et) polymer grade, Shanghai production
TEA industrial imports
The formulation system of acid anhydride epoxy paint crosslinking agent has a low viscosity and long use period, such as high temperature crosslinking, good thermal stability and electrical properties. Organic acid anhydride epoxy crosslinking agent can be divided into: aromatic anhydride, fatty acid anhydride and halogenated anhydride.
1. The crosslinking mechanism of acid anhydride epoxy crosslinking agent
The reaction of the acid anhydride crosslinking epoxy resin requires a small amount of alcohol, water and free acid in the resin/anhydride system, which can be crosslinked slowly through heating. Therefore, the acid anhydride does not react directly with the epoxies and must open the ring of anhydride.
1. The effect of active hydrogen on acid anhydride
Bisphenol A epoxy contains hydroxyl, which can open acid anhydride. A hydroxyl group produces a carboxyl group, and the polyol can connect two anhydride molecules to form a cross-linking effect. Join the hydroxyl compounds such as ethylene glycol, glycerin, low molecular polyether containing hydroxyl and so on, can accelerate the ring-opening reaction, water can make the two carboxylic anhydride, therefore humidity affect anhydride crosslinking.
Esterification reaction: this is the main reaction of the acid anhydride crosslinking epoxy resin. The carboxyl group is formed with the epoxy base, and the ester base is formed. The carboxyl group formed by the esterification reaction, which further makes the acid anhydride open ring, reacts with the epoxy base, and finally produces the three-dimensional structure; At high temperature, some carboxyl groups can catalyze the opening ring of epoxy and generate the structure with ether bond.
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
1. The effect of 2 - level amine (tertiary amine) on acid anhydride
The tertiary amine forms an ion pair with the acid anhydride, the epoxy is inserted into the ion pair, the carboxyl anion opens the epoxy, produces the ester bond, and produces a new anion. For example, 2-ethyl-4-methyl imidazole and 2, 4, 6 -- (N, N. 1, n-1, methylaminomethyl) - phenol is K - 54 # (foreign call DMP - 30 #).
2. The variety of anhydride crosslinking agent
2. 1 maleic anhydride (MA) and modificator
A. Maleic anhydride: white crystal, melting temperature of 52.8 ℃. Its acidity is strong, the crosslinking speed is fast, the dosage is 20-40%, the crosslinking thing is more brittle and poisonous.
B. : 70 # anhydride by butadiene and maleic anhydride synthesis, volatile small, toxicity and dosage is 70-80%, crosslinking conditions is 150 ℃, 4 h.
C. 647 # anhydride: synthesis of dicyclopentadiene and maleic anhydride. Light yellow liquid, dosage of 80-90 %. Crosslinking conditions during 150-150 ℃, 8 h.
D. 308 tung oil anhydride: maleic anhydride modified by tung oil. The dosage is 100-200 %, the crosslinking is soft, the extension is good, the heat resistance is bad. Crosslinking conditions: 100-120 ℃, 6-10 h.
E. Methyl time within four hydrogen phthalic anhydride (MNA) : light yellow liquid, below the melting temperature of 12 ℃, dosage of 80%, the crosslinking HDT is 160 ℃, the viscosity of 138 centipoise, boiling point 250 ℃ >.
2. 2. Aromatic polyanhydride:
Aromatic polyanhydride crosslinking has the characteristics of high resistance to acid and alkali resistance.
A. Pyromellitic dianhydride (PMTA) : white crystal, melting point is 286 ℃, temperature does not dissolve in resin, and the epoxy resin reactivity is extremely strong. Dosage for 45-55%, thermal deformation temperature of crosslinked > 200 ℃, as the high temperature resistant adhesive. Such as:
618 # epoxy resin 100
Homobenzene tetrazoic acid anhydride 59
Tetrahydrofurfuryl alcohol 20
Preheat resin 75-89 ℃, pour all pyromellitic dianhydride, four hydrogen furfuryl alcohol solution, then mixed with the mixture of 80 ℃ has 20 min period shall apply.
Copyright: Zhang Jia Gang YaRui Chemical co.,Ltd
Copyright: Zhang Jia Gang YaRui Chemical co.,Ltd
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