Carboxymethyl cellulose CMC, sodium carboxymethyl starch (CMS), the price is relatively cheap (from the performance of the product itself, CMC is a grade lower than Fuying HPMC), carboxymethyl cellulose is used for low-grade putty powder for interior walls Among them, the water retention and stability are much worse than that of hydroxypropyl methylcellulose, so it cannot be used in waterproof putty and external thermal insulation dry mix.
Many people think that these celluloses are alkaline, and cement and lime calcium powder are also alkaline, and they think they can be used in combination, but carboxymethyl cellulose and sodium carboxymethyl starch are not single elements, and the chloroacetic acid used in their production process It is acidic, and the residual substances in the process of cellulose production react with cement and lime calcium powder, so they cannot be combined. Many manufacturers have suffered great losses due to this, so attention should be paid. The uses of carboxymethyl cellulose and hydroxypropyl methyl cellulose are only similar, but their functions are very different, and the technical indicators of the two are far apart. The main raw materials of the two are the same refined cotton, but their auxiliary materials, production equipment, and process flow are different. The production equipment and process of hydroxypropyl methylcellulose are much more complicated. The two are not a production process at all, and other accessories are also different, so the uses are also different. They cannot be replaced, nor can they be combined with each other to reduce costs.
Hydroxypropyl methylcellulose (hpmc) has stable chemical properties, mildew resistance, the best water retention and thickening effect, and is not affected by pH changes. The viscosity of 100,000 is suitable for putty powder, and the viscosity of 150,000 to 200,000 is suitable for putty powder. In mortar, it mainly increases the leveling property and constructability, and can reduce the amount of cement.
The function is that the cement mortar has a solidification period, and it needs to be maintained during the solidification period, and it needs to be supplied with water to keep it moist. Due to the water retention effect of cellulose, the water required for cement mortar solidification is guaranteed from the water retention of cellulose, so the solidification effect can be achieved without maintenance.