The use of hydroxyethyl cellulose in latex paint is as follows: 1. Add directly when grinding pigment: this method is simple, and the time used is short. The detailed steps are as follows: (1) add proper purified water (normally, ethylene glycol, wetting agent and film-forming agent are added at this time)(2) start stirring at low speed continuously and slowly add hydroxyethyl cellulose (3) continue stirring until all particles are wet (4) add mildew inhibitor; PH regulator, etc. (5) stir until all hydroxyethyl cellulose completely dissolved (solution viscosity increase) before adding the other components of the formula, grinding until paint.
2.Equipped with mother liquor waiting for use: this method is first equipped with a higher concentration of mother liquor, and then added to latex paint, this method has the advantage of greater flexibility, can be directly added to paint products, but must be stored properly. The steps and methods are similar to steps (1)-(4) in method 1, except that a high shear agitator is not required, and only a agitator with enough power to keep the hydroxyethyl fibers uniformly dispersed in the solution is required. Keep stirring until it dissolves completely into a viscous solution. Must note that: mildew inhibitor must be added to mother liquor as soon as possible. 3. Congee with the phenology: as organic solvents for hydroxyethyl cellulose is a bad solvent, so these organic solvents can be used to prepare congee. Commonly used organic solvents such as ethylene glycol, propylene glycol, and film-forming agents (such as hexanediol or diethylene glycol butyl acetate) , ice water is also a poor solvent, so it is often used with organic liquids to prepare porridge. Porridge-like hydroxyethyl cellulose can be added directly to the paint. Hydroxyethyl cellulose has been fully inflated in the porridge. When lacquer is added, it dissolves immediately and thickens. After adding, it must be stirred continuously until the hydroxyethyl cellulose is completely dissolved and uniform. Generally porridge is with six parts of organic solvent or ice water and a part of hydroxyethyl cellulose mixture, about 5-30 minutes later, hydroxyethyl cellulose will be hydrolyzed and swelling. Summer when the general water humidity is too high, not suitable for equipped with porridge.
3.Four. Note when preparing mother liquor of hydroxyethyl cellulose since hydroxyethyl cellulose is a treated powdered particle, it is easy to operate and dissolve in water by paying attention to the following. 1 before and after adding hydroxyethyl cellulose, the mixture must be stirred continuously until the solution is completely transparent and clear. 2 must be sifted into the mixing drum, do not have a large number of lumps or balls of hydroxyethyl cellulose has been added directly into the mixing drum. 3 the solubility of hydroxyethyl cellulose is related to water temperature and pH value in water, which should be paid special attention to. 4 do not add some basic substances to the mixture before hydroxyethyl cellulose powder is saturated with water. Increasing pH after soaking helps to dissolve. 5 as far as possible, early to add anti-mildew agent. 6 when using high viscosity hydroxyethyl cellulose, the mother liquor concentration can not be higher than 2.5-3% (gravimeter) , otherwise the mother liquor is difficult to operate. Factors affecting the viscosity of latex paint:
1 The more the content of air bubbles in paint, the higher the viscosity. 2 the amount of surface activator and water used in the paint formula is appropriate. 3 in the synthesis of latex, the amount of residual catalysts and other oxides. 4 the amount of other natural thickeners in the paint formula and the proportion with hydroxyethyl cellulose. 5 in the process of paint, adding thickener step sequence is appropriate. 6 due to excessive agitation so that when dispersed moisture overheating. 7 microbial corrosion of Thickener.
Post time: Oct-24-2023