1. Add directly when grinding the pigment: This method is the easiest and takes less time. The detailed steps are as follows:
(1) Add appropriate purified water to the vat of the high-cut agitator (generally, ethylene glycol, wetting agent and film-forming agent are all added at this time)
(2) Start stirring continuously at low speed and slowly add hydroxyethyl cellulose
(3) Continue stirring until all particles are soaked through
(4) Add antifungal agent, PH adjuster, etc.
(5) Stir until all the hydroxyethyl cellulose is completely dissolved (the viscosity of the solution increases significantly) before adding other components in the formula, and grind until it becomes paint.
2. Prepare the mother liquor for use: This method is to prepare the mother liquor with higher concentration first, and then add it to the latex paint. The advantage of this method is that it has greater flexibility and can be directly added to the finished paint, but it must be properly stored. The steps and methods are similar to the steps (1)-(4) in Method 1, the difference is that there is no need for a high-shear agitator, and only some agitators with sufficient power to keep the hydroxyethyl fibers uniformly dispersed in the solution are used. Can. Continue constant stirring until completely dissolved into a viscous solution. It should be noted that the antifungal agent must be added to the mother liquor as soon as possible.
3. For porridge phenology: Since organic solvents are poor solvents for hydroxyethyl cellulose, these organic solvents can be used to prepare porridge. The most commonly used organic solvents such as ethylene glycol, propylene glycol, and film-forming agents (such as hexylene glycol or diethylene glycol butyl acetate), ice water is also a poor solvent, so ice water is often used together with organic liquids. To prepare porridge.
The porridge-like hydroxyethyl cellulose can be directly added to the paint. The hydroxyethyl cellulose has been fully swollen in the porridge. When added to the paint, it immediately dissolves and thickens. After adding, it must be stirred continuously until the hydroxyethyl cellulose is completely dissolved and uniform. Generally, the porridge is mixed with six parts of organic solvent or ice water and one part of hydroxyethyl cellulose. After about 5-30 minutes, the hydroxyethyl cellulose will be hydrolyzed and swelled obviously. In summer, the humidity of the general water is too high, and it is not suitable to be used for porridge.
4. Matters needing attention when preparing hydroxyethyl cellulose mother liquor
Since hydroxyethyl cellulose is a processed powder, it is easy to handle and dissolve in water as long as the following matters are noted.
1) Before and after adding hydroxyethyl cellulose, it is necessary to keep stirring until the solution is completely transparent and clear.
2) It must be sieved into the mixing barrel slowly, and do not add the hydroxyethyl cellulose that has been formed into lumps or balls directly into the mixing barrel.
3) Water temperature and pH value in water have a significant relationship with the dissolution of hydroxyethyl cellulose, so special attention should be paid to it.
4) Do not add some alkaline substances to the mixture before the hydroxyethyl cellulose powder is soaked with water. Raising the pH only after wetting will aid in dissolution.
5) As far as possible, add antifungal agent as early as possible.
6) When using high-viscosity hydroxyethyl cellulose, the concentration of the mother liquor should not be higher than 2.5-3% (by weight), otherwise the mother liquor will be difficult to handle.
Post time: Nov-15-2022