The construction performance of waterborne self crosslinking paint is flawed, for example, it is not easy to grasp the thickness of spray paint, orange peel cracks appear on the thick surface, poor base treatment and poor adhesion. The waterborne primers produced by phenol modified styrene acrylic emulsion are easy to embroider, especially those with rusty metal substrates. This paper focuses on self crosslinking water-based paint for metal color panels, because the coating method is wire rod scraping and high-temperature curing, which is not restricted by natural conditions, and avoids the uneven coating phenomenon due to spraying, spraying and other process construction.
1.Phenol modified styrene acrylic emulsion waterborne primer
The paint for metal substrate, especially the metal surface rust situation, because the paint medium is water, in addition to a certain amount of surfactant in the emulsion agent, to rust oxidation base easily dissolved, when water evaporation will bring it to the coating surface, and the water-based primer the film density is uneven, rust stains from large parts of the voids overflow, thus forming the rust.
In view of this problem, first, the selection and adjustment of the variety and dosage of emulsifier have been made. A part of the reactive emulsifier is used instead of the general emulsifier. The reactive emulsifier does not distribute on the surface of latex ion, and it does not match with the rust of iron oxide. Secondly, a certain amount of functional monomers can improve the inhibition performance of the emulsion to oxidation rust and the permeability to the substrate, and the adhesion after the film formation.
2. Self crosslinking waterborne lacquer emulsion
The advantages of self crosslinking emulsion has long been needless to say. The main problems in the process of operation are studied. Self crosslinking acrylic emulsion is used to produce metal color plate paint, and the products are improved in terms of high temperature resistance, impact resistance, scratch resistance, folding and dense fullness.
First, a partial general-purpose emulsifier is used to replace the phosphorous salt emulsifier. The original self crosslinking emulsion was improved with a certain amount of adhesion monomers. On this basis, the copolymerization of epoxy resin with its graft is also combined.
There are aliphatic hydroxyl groups, ether groups and active epoxy groups in the molecular structure of the ring hydrogen resin, which are easily graft copolymerized with acrylic emulsion. Due to the characteristics of the ring hydrogen molecule and the electromagnetic attraction between the coated metal surfaces, the hydrogen bonds between the ring hydrogen group and the metal surface produce chemical bonds. The binding between molecules plays a strong role in chemical bonding. It will improve the adhesion of the paint film. The shrinkage rate of epoxy resin is small. It can improve the density and fullness of the paint film, and the epoxy resin has excellent high and low temperature resistance (-55 C ~200 C). The modified self - crosslinked emulsion is adapted to the requirements of the heat cured metal plate. Through a variety of technical changes above, it improves the tensile, bending and stamping properties of the film. Secondly, the chemical stability of epoxy resin is good, and the modified self crosslinked emulsion will also improve the properties of acid and alkali resistance and solvent resistance.