| As the main form of using wind energy, wind power attracted worldwide attention. China has gradually become the main wind power user and wind power facility manufacturer in the world. The coatings system in the internal surface the wind tower is generally zinc epoxy primer and phenalkamine epoxy coatings, without topcoats such as polyurethane coatings. Phenalkamine epoxy coating has many advantages, such as quick drying, curing at low temperature, no blooming at low temperature, etc. But it has a very notable problem, it will yellow very fast in the sunshine. The main purpose of this study is to develop a coating using in the internal surface of wind tower, with similar properties and cost with phenalkamine epoxy coating, but has better yellowing resistance.There are three strategies in this study:the first is using UV absorber and light stabilizer, the second is the blending of phenalkamine with other kinds of curing agents with good yellowing resistance, and the third is looking for new kind of curing agents.The experimental results of adding several amounts of UV absorber and light stabilizer showed that they had no improvement to the yellowing resistance of phenalkamine epoxy coating. The test results of blending phenalkamine with some other kinds of curing agents with good yellowing resistance, such as polyamide, cycloaliphatic amines, amine adduct etc. also have no improvement. According to the mechanism of the yellowing of phenalkamine epoxy coating, we got a new kind of curing agents, which is a modified phenalkamine, called "phenalkamide", in fact, it is the hydroxyalkylation of cardanol by replacing the phenol’s hydroxyl group with a more stable hydroxyalkoxyl group to get monohydroxyalkylcardanyl ether with light color and better yellowing resistance.The test results showed that it had better yellowing resistance and could be cured at low temperature. Basing on this new curing agent, a new product was developed to meet the similar properties and cost with phenalkamine coating. |
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