Water-based paint is a kind of paint that uses water as a solvent. As a substitute for solvent-containing paint systems, it has gradually been recognized by people. It has certain advantages in terms of performance, and its products are quickly accepted by the market, and they are called high-tech replacement products. The production process of water-based coatings is described below:
(1) Basic production process of water-based paint The production process of water-based paint is a process in which raw materials of various components are put into a certain order and dispersed evenly. The production process of general latex paint includes 3 parts:
① Preparation of slurry: First, put water, dispersant, defoamer, preservative and other liquid materials into the dispersion tank, stir evenly, put in the coloring pigment and extender pigment in turn under the stirring state, and accelerate the dispersion for 20~40 minutes ;
② Preparation of water-based paint: put emulsion into the paint mixing tank, then add thickener, ph regulator, antifreeze, film-forming aid, defoamer and other additives, stir for about 15 minutes, until it is completely uniform, detect material;
③ Paint filtration and product packaging: In the production process of latex paint, since a small part of the pigment (filler) has not been dispersed, or due to demulsification into particles, or impurities exist in the paint, the paint at this time needs to be filtered Good quality products can only be obtained by removing coarse particles and impurities. According to different product requirements, different specifications of screens and different containers can be selected for packaging and measured properly, so as to obtain the final product.
(2) Key points in the preparation of water-based coatings:
① The formulation materials should use pigments with good dispersibility and ultra-fine fillers as much as possible, so as to stably improve the product quality, cancel the grinding operation, simplify the production process, and improve production efficiency;
② In the early dispersion stage, an appropriate amount of HEC can be added in advance, which not only helps to disperse, but also prevents or reduces the phenomenon of slurry sticking to the wall and improves the dispersion effect;
③ Before adding the liquid thickener, it should be diluted with 3~5 times of water as much as possible, and then added slowly under full stirring, so as to prevent the emulsion from agglomerating or forming micelles due to the high concentration of the local thickener. The thickener can After the slurry is dispersed, put it into the slurry and stir fully to avoid the above problems;
④ Add half of the defoamer to the slurry, and the other half to the paint mixing process, which can make the defoaming effect better; during the paint mixing process, the stirring speed should be controlled at 200~400r/min to prevent A large number of air bubbles are introduced during the production process, which affects the quality of the paint.
