Water-based epoxy curing agent based on castor oil triglycidyl ether and preparation method of curing agent

Abstract

The invention belongs to the technical field of coatings, and discloses a water-based epoxy curing agent based on castor oil triglycidyl ether and a preparation method of the curing agent. The preparation method comprises the following steps: performing a reaction on bisphenol epoxy resin, polyetherol diglycidyl ether and a polyamine to prepare an epoxy-polyamine addition product with -NH2 groupsat two ends, adding the castor oil triglycidyl ether, performing a branching reaction to obtain a prepolymer with -NH2 groups at three branched chain tail ends, adding a monoepoxy compound to block terminal primary amine hydrogen, and finally adding water for dispersion to obtain the water-based epoxy curing agent. The water-based epoxy curing agent obtained by the method has the advantages of a long pot life, low viscosity and easy construction when used with water-based epoxy resin, and the cured product has a large cross-linking degree, has good flexibility while having good corrosion resistance, and overcomes the defects of low toughness and high brittleness of an ordinary epoxy coating layer.

Description

technical field [0001] The invention belongs to the technical field of coatings, and in particular relates to a water-based epoxy curing agent based on castor oil triglycidyl ether and a preparation method thereof. Background technique [0002] Water-based epoxy coatings are one of the representative works of water-based coatings, which have the advantages of low VOC content, low odor, low flammability, high safety and easy cleaning with water. Since epoxy resin is a thermosetting resin, it has no function when it is formed into a film alone. Only when water-based epoxy curing agent is added, can it form a three-dimensional network cross-linked structure, showing excellent performance. In the water-based epoxy curing agent, water is used as a solvent or dispersion medium. Due to the high surface tension and evaporation heat of water, the water-based curing agent has a long drying time for film formation, poor wetting and dispersing performance, and low temperature curing is ...

AI Technical Summary

Problems solved by technology

However, when using this kind of water-based epoxy curing agent to prepare coatings, there are problems such as slow surface drying speed, short pot life, whitening, foaming and poor water resistance of the coating film during the film forming process.

For example, the patent CN1958639A discloses a preparation method of a water-based epoxy curing agent. The water-based epoxy curing agent is finally prepared by neutralizing acetic acid to form a salt, but the addition of an organic acid will cause the product to be unstable in storage, and it is easy to cause rust on the metal surface, resulting in a decrease in the performance of the coating

In the patent CN106046325A, a branched-chain water-based epoxy curing agent is obtained by adding TMPEG (trimethylolpropane triglycidyl ether), but the amount of TMPEG is not easy to control, the reaction process is easy to gel, and the cured product is brittle. restricted

In patent CN107556914A, a castor oil prepolymer is introduced into the coating system, and the obtained coating film has certain flexibility and adhesion, but its water resistance and solvent resistance are relatively poor.

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