This method is the simplest and takes the shortest time. The detailed steps are as follows:
(1) Add appropriate purified water into the vat of the high-shear mixer (generally, ethylene glycol, wetting agent and film-forming agent are all added at this time)
(2) Start to stir continuously at low speed and slowly add hydroxyethyl cellulose
(3) Continue stirring until all particles are soaked
(4) Add antifungal agent, PH regulator, 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 the paint is formed.
This method is to prepare a mother liquor with a 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 method are similar to steps (1)-(4) in method 1, the difference is that no high-shear agitator is needed, only some agitators with sufficient power to keep the hydroxyethyl fiber dispersed evenly in the solution are Can. Continue to stir continuously 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.
Since organic solvents are poor solvents for hydroxyethyl cellulose, these organic solvents can be used to prepare the porridge. The most commonly used organic solvents such as ethylene glycol, propylene glycol, and film-forming agents (such as ethylene glycol or diethylene glycol butyl acetate), ice water is also a poor solvent, so ice water is often used together with organic liquids. Yu equipped with porridge. Porridge-like hydroxyethyl cellulose can be directly added to the paint. Hydroxyethyl cellulose has been fully soaked in porridge. When added to the paint, it dissolves immediately and acts as a thickener. After adding, keep stirring until the hydroxyethyl cellulose is completely dissolved and uniform. Generally, porridge is made by mixing six parts of organic solvent or ice water with one part of hydroxyethyl cellulose. After about 5-30 minutes, the hydroxyethyl cellulose will be hydrolyzed and swell obviously. In summer, the humidity of general water is too high, so it is not suitable for preparing porridge.
Since hydroxyethyl cellulose is a processed powder, it is easy to handle and dissolve it in water as long as the following items are paid attention to.
(1) Before and after adding hydroxyethyl cellulose, it must be stirred continuously until the solution is completely transparent and clear.
(2) It must be slowly sieved into the mixing tank, do not directly add a large amount of hydroxyethyl cellulose that has formed lumps or balls into the mixing tank.
(3) The water temperature and the pH value in the water have a significant relationship with the dissolution of hydroxyethyl cellulose, so special attention must be paid.
(4) Do not add some alkaline substances to the mixture before the hydroxyethyl cellulose powder is soaked with water. Raising the pH after wetting out aids dissolution.
(5) As far as possible, add anti-fungal agent early.
(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.