Hydroxypropyl Methyl Cellulose Ether (HPMC) are referred to as Methyl Cellulose ether (MC). MC is one of the most important additives in dry powder mortar which mainly plays the role of water retention and thickening.
MC is a kind of powdered cellulose ether made of wood fiber or refined short cotton fiber as the main raw material after chemical treatment through the reaction of etherification such as ethylene chloride, propylene chloride and ethylene oxide. The molecular structure of cellulose is composed of molecular bonds of dehydrated glucose units, each of which contains three hydroxyl groups. Under certain conditions, the hydroxyl group is replaced by methyl, hydroxyethyl, hydroxpropyl and other groups to produce various kinds of cellulose. Methyl cellulose is replaced by methyl, hydroxyethyl cellulose is replaced by hydroxyethyl and hydroxpropyl cellulose is replaced by hydroxypropyl. MC is a kind of mixed ether through etherification which is mainly methyl but contains a small amount of hydroxyethyl or hydroxypropyl so it is called MHEC or HPMC. Due to the different substitutes such as methy, hydroxyethyl, hydroxypropyl and degree of substitution, cellulose ethers have produced various types and brands. Different varieties can be widely used in different fields, such as construction, food and medicine industry, daily chemical industry, petroleum industry, etc.
At present, there are four kinds of cellulose ethers with the largest production in the world, and their main uses are as follows:
1. HPMC takes up 80% of chemical building materials and 20% of coating industry. This kind of cellulose ether is mainly used in dry mortar in the world. It has better water retention and thickening property and more stable quality than other types of cellulose ether.
2. HPMC is mainly used in medicine, daily chemical industry and chemical building materials industry, but its water retention and thickening properties are slightly lower than that of HPMC, especially at high temperature. Cellulose ether in China is mainly HPMC.
3. Hydroxyethyl cellulose ether (HEC) is mainly used as stabilizer in coating industry and oil field drilling mud, but its dispersion, thickening and water retention are significantly lower than that of MC.
4. Sodium Carboxy Methyl Cellulose (CMC) is mainly used in daily chemical, food, paper, textile and other industries with a small amount used in coating industry.