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Use of epoxy resin coating crosslinking agent
2017-7-23 17:50:31
Use of epoxy resin coating crosslinking agent
1. The calculation of the amount of the crosslinking agent of amines
The calculation method of the dosage of amines is based on the action of an active hydrogen and an epoxyl group. The dosage of various kinds of amine and secondary amine is calculated according to the following calculation:
W = (M/Hn) * E
Type:
W - a quality of the amine crosslinking agent needed for each 100g epoxy resin, g;
M - amine crosslinking agent;
Hn - the number of active hydrogen atoms in the amino group of the crosslinking agent;
E one - one epoxide in epoxy.
For example, using ethylenediamine as crosslinking agent, the e-44 epoxy resin is crosslinked, and the dosage of ethylene diamine is required for every loog epoxy resin. Solution: the molecular formula of ethylenediamine is H2N - CH2, 1 NH2
The molecular weight of ethylenediamine is 60
The active hydrogen atom of ethylenediamine is equal to 4
The epoxy value of the e-44 epoxy resin was found in the table, E = 0.40 ~ 0.47, so W Max = 60/4 x 0.47 = 7.05 (g) W minimum = 60/4 * 0.40 = 6 (g).
For every 100g e-44 epoxy resin needs 6 ~ 7g b diamine crosslinking agent. In fact, as the size of the amine molecule, as well as the reaction ability and the volatile situation, generally more than 10 percent more than the theoretical calculation.
Chinese name: Diethyl toluene diamine(DETDA)Physical and chemical properties: light yellow transparent liquid, slightly soluble in water, soluble in alcohols, ethers, ketones and other polar organic solvents, and polyether, polyester polyol compatibility.
Density 1.022
Viscosity (20 ℃) ??mPa·ss290±10
Pour Point ℃-9
Boiling point of310°C
Flash Point°C161.1°C
The dosage of epoxy resin crosslinking agent was calculated
Acid anhydride crosslinking agent is usually calculated by the following formula:
W = AE · E · K type: W - a quality of acid anhydride cross-linking agent needed for every 100g epoxy resin; g;
AE 1 - acid anhydride molar mass, kg/mol; K -- the amount of acid anhydride needed for each molar mass of epoxy. Empirical data, it changes within 0.5 ~ 1.1 fan enclosure and generally takes 0.85.
For example, the epoxy resin of 100g epoxy is 0.43. If it is used as its hardener by the neighbor phthalic anhydride (PA), how to use more suitable
Its molecular weight M = 148
E = 0.43
Experience value K = 0.85
Therefore, the appropriate dosage is: W = 148 x 0.43 * 0.85 x = 54.1 (g).
The epoxy resin of 100g is 0.43, and it is better to use the adjacent phthalic anhydride with 54g. The actual usage is also higher than the theoretical calculation.
The dosage of crosslinking agent is generally higher than that of theoretical calculation. Firstly, there is the loss of volatilization during the process of preparation and operation. The second is not easy to mix with the resin. However, when the dosage of the hardener is too large, the resin chain will be terminated and the molecular weight of the hardened material will be reduced, making the resin brittle after the crosslinking.
The above calculation values refer to the pure crosslinking agent, which is 100 per cent. When this purity is not reached, the conversion adjustment shall be carried out.
According to the hydrolysis velocity test, the hydrolysis rate of silicon phosphate is much lower than that of other crosslinking agents, so the phosphoric acid can unite the water glass binder to improve the water resistance and the anti-folding strength.
Copyright: Zhang Jia Gang YaRui Chemical co.,Ltd
Copyright: Zhang Jia Gang YaRui Chemical co.,Ltd
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