A variety of epoxy resin curing agents will have their own characteristics, understand the description of epoxy curing agents, and make better use of these curing agents. Epoxy resin curing agents generally have their own grades. Of course, due to trade secrets and other reasons, manufacturers generally keep these brands secret. Senior decoration masters will share with you the basic structure of some epoxy resin curing agents.
D-8
The ketone aldehyde epoxy compound and the aliphatic polyamine amine adduct have low viscosity and moderate curing speed, and the coating is suitable for the factory. It is easy to apply and the formed film has good anti-corrosion properties, but the color is darker.
T-31 modified amine
Phenolic-amine adduct, high viscosity, fast curing speed, and can be cured underwater. However, the coating film is brittle.
591#
Diethylenetriamine-acrylonitrile copolymer (B cyanoethylated), light yellow liquid, low toxicity, low calorific value, long service life, heat curing, curing conditions: 80 ° C, 12 h; dosage 20-25% .
GY-051
Reduced amine light brown liquid, dosage 12-14%, curing conditions: room temperature, 48 hours h.
590#
The condensate of m-phenylenediamine and benzophenone phenyl ether is a brown-black liquid, and the softening point is below 20 ° C, and the amount is 15-20%, which can be cured at room temperature.
701#
Phenol formaldehyde hexamethylene diamine condensate 25-35%, solidified at room temperature for 4-8h.
702#
The amount of phenylformaldehyde meta-phenylenediamine condensate is 23-35%, and it is cured at room temperature for 4-8 hours.
703#
The amount of phenol formaldehyde ethylenediamine condensate is 36-42%, and it is cured at room temperature for 4-8 hours.
706# curing agent
Tertiary ester of triisopropanol titanate brown yellow liquid, the amount is 20-30%, curing: 100 ° C, 1 h; 142 ° C, 2 h.
120#:
Ethylenediamine and diethylenetriamine are reacted with ethylene oxide in the presence of a small amount of water. A viscous liquid that is more than 10003 times less volatile and toxic than ethylenediamine. Fast curing epoxy resin at room temperature, 16-18%
593
The adduct of diethylenetriamine and butyl glycidyl ether has a viscosity of 0.2 Pa.s at 25 ° C, and has high activity and low toxicity.
The epoxy resin is rapidly cured at room temperature, and the cured product is flexible. The dosage is 23-25%, and the reaction with the epoxy resin is mild, and the service life is about 1 hour.
70# anhydride
The synthesis toxicity and volatility of butadiene and maleic anhydride are small, the dosage is 70-80%, and the curing condition is 150 ° C, 4H. Liquid anhydride produced by Tianjin Jindong Chemical Plant. Light yellow liquid with low viscosity.
The 647# anhydride is synthesized from dicyclopentadiene and maleic anhydride. Light yellow liquid, the dosage is 80-90%. Curing conditions 150-160 ° C, 8H. Tianjin Jindong Chemical Plant production.
308 tung oil anhydride
Maleic anhydride modified by tung oil. The dosage is 100-200%, the cured product is soft, the elongation is good, and the heat resistance is poor. Curing conditions: 100-120 ° C, 6-10H.
704#
2 methylimidazole and propylene oxide butyl ether adduct room temperature is brown red viscous liquid, fast curing epoxy resin at 80-120 ° C, the amount is 10%
705#
2 adduct of methylimidazole and epoxy propyl isooctyl ether at room temperature is brown red viscous liquid, fast curing epoxy resin at 80-120 ° C, the amount is 15%
Determination of the amount of epoxy resin curing agent
1. Calculation of the amount of amine curing agent
The method for calculating the amount of the amine curing agent is based on the action of an active hydrogen on the amine group and an epoxy group. The amount of various primary and secondary amines is calculated by the following formula: W = (M / Hn) × E
Where: W—the mass of the amine curing agent required per 100 g of epoxy resin, g; M—the molecular weight of the amine curing agent;
Hn - the number of active hydrogen atoms on the amine group in the curing agent molecule; the epoxy value of the E-epoxy resin.
For example: Ethylenediamine is used as a curing agent to cure E-44 epoxy resin, and the amount of ethylenediamine required for each loog epoxy resin is determined. Solution: The molecular formula of ethylenediamine is H2N-CH2-NH2. The molecular weight of ethylenediamine is M=60. The number of active hydrogen atoms of ethylenediamine is Hn=4.
From the table, it is found that the epoxy value of E-44 epoxy resin is E=0.40~0.47, then
Wmax=60/4×0.47=7.05(g) Wmin=60/4×0.40=6(g)
That is, 6~7g of ethylenediamine curing agent is needed per 100g of E-44 epoxy resin. In fact, with the size of the amine molecule, as well as the reactivity and volatilization, it is generally more than 10% more than the theoretically calculated value. 2. Calculation of the dosage of acid anhydride curing agent
The amount of the acid anhydride curing agent is usually determined by the following formula: W = AE · E · K where: W - the mass of the anhydride curing agent required per 100 g of epoxy resin, g;
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AE-anhydride molar mass, kg/mol;
K - the amount of anhydride required per mole of epoxy group, mol. Empirical data, which varies from 0.5 to 1.1, typically 0.85.
For example: For 100g epoxy resin with an epoxy value of 0.43, what is the appropriate amount if phthalic anhydride (PA) is used as its hardener?
Solution: The molecular formula of phthalic anhydride is: Its molecular weight M=148
E=0.43 The empirical value is K=0.85, so the suitable amount is: W=148×0.43×0.85×=54.1(g)
That is, 100 g of an epoxy resin having an epoxy value of 0.43 is preferably used as a curing agent of about 54 g of phthalic anhydride. The actual usage is also higher than the theoretically calculated usage.
There are two reasons why the amount of curing agent is generally higher than the theoretical calculation value. One is that there is a volatilization loss during the preparation process and the operation process; the other is that it is not easy to mix with the resin. However, when the amount of the hardener is too large, the resin chain is terminated to grow, the molecular weight of the cured product is lowered, and the cured resin is brittle.
The above calculated values ​​refer to a pure curing agent, that is, 100%. When this purity is not achieved, conversion adjustments should be made.
The above content is the main content of the epoxy resin curing agent shared by the decorator and everyone today.
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