Cellulose Ether-Some common sense of hydroxypropyl methylcellulose products
1. What is the viscosity of hydroxypropyl methyl cellulose (HPMC)? SLEO reminds you that the putty powder is generally 100,000 yuan, and the mortar is more demanding, and it is easy to use 150,000 yuan. Moreover, the most important role of hydroxypropyl methylcellulose is to retain water, followed by thickening. In putty powder, as long as the water retention is good and the viscosity is lower (70,000-80,000), it is also possible. Of course, the higher the viscosity, the better the relative water retention. When the viscosity exceeds 100,000, the effect of viscosity on water retention is Not much.
2. What are the main technical indicators of hydroxypropyl methylcellulose? Hydroxypropyl content and viscosity, most users care about these two indicators. The higher the hydroxypropyl content, the better the water retention. The viscosity is high, the water retention is relatively (rather than absolute), and the viscosity is high, and it is better used in cement mortar.
3. What are the main raw materials of hydroxypropyl methyl cellulose? The main raw materials of hydroxypropyl methyl cellulose (HPMC): refined cotton, methyl chloride, propylene oxide, other raw materials include flake alkali, acid, Toluene, isopropanol, etc.
4. Is the powder drop of putty powder related to hydroxypropyl methylcellulose? The powder drop of putty powder is mainly related to the quality of ash calcium, and has little to do with HPMC. The low calcium content of ash calcium and the inappropriate ratio of CaO and Ca(OH)2 in ash calcium will cause powder drop. If it has something to do with HPMC, then the poor water retention of HPMC will also cause powder drop.
5. What is the reason for the odor of hydroxypropyl methylcellulose? Hydroxypropyl methylcellulose produced by solvent method is made of toluene and isopropyl alcohol as solvents. If the washing is not very good, there will be some residual smell .
Since the properties of hydroxypropyl methylcellulose are similar to other water-soluble ethers, it can be used as a film-forming agent, thickener, emulsifier and stabilizer in latex coatings and water-soluble resin coating components, so that the coating film has good properties. Wear resistance, leveling and adhesion, and improved surface tension, acid-base stability and compatibility with metallic pigments. Since the gel point of hydroxypropyl methylcellulose is higher than that of methylcellulose, the gel temperature is improved, and its resistance to bacterial erosion is also stronger than that of other cellulose ethers, so it is used as a thickening agent for water emulsions. It has good viscosity storage stability and good miscibility with organic solvents. Its excellent dispersibility makes it especially suitable for use as a dispersant in emulsion coatings.
1) The coatings prepared with various viscosities of hydroxypropyl methylcellulose have good abrasion resistance, high temperature resistance, resistance to bacterial degradation, washing resistance and acid-base stability. Thickener for paint strippers of ethanol, propanol, isopropanol, ethylene glycol, acetone, methyl ethyl ketone or diketone alcohol, it is used to formulate emulsion coatings with excellent wet grinding properties. Better than HEC and EHEC and CMC as paint thickener.
2) It has a good effect as a thickener for white water-based polyvinyl acetate coatings. The degree of substitution of cellulose ether is increased, and the resistance to bacterial erosion is also enhanced.
3) Hydroxypropyl methylcellulose with high substitution degree (DS1.76~2.15) has better resistance to bacterial erosion than low substitution degree, and has better viscosity stability in polyvinyl acetate thickener. Inappropriate cellulose ethers reduce the viscosity of the coating due to chain degradation of the cellulose ethers during storage.
4) The use of HPMC with a high degree of substitution can improve and control the properties of water-based coatings. It improves paint viscosity, surface tension, gel temperature and organic additive compatibility, and controls the effects of bacteria on paint in tropical regions.