1. Overview of hydroxypropyl methyl cellulose In recent years, with the rapid development of China’s industry step by step, non-ionic cellulose ether hydroxypropyl methyl cellulose (HPMC), methyl cellulose (MC) products have been widely used, and the application field is also expanding, and the application market is increasing.
In 2000, China’s HPMC and MC consumption was 5000 tons, where 1000 tons are produced by domestic manufacturers and imported 4000 tons of HPMC annually.In recent years, due to the widespread use of HPMC products in construction, coating, medicine, chemical industry and other fields, the HPMC consumption in China soared to 15,000 tons in 2005.
High-grade HPMC is still dependent on imports of about 5,000 tons.In the future production and operation process, according to the domestic and foreign market supply and demand situation, the need Actively expand the marketing scope of products, according to the expansion of the sales market, the need to improve its production capacity accordingly, at the same time, but also timely research and develop new products in line with the market demand, such as: HPMC production, to meet the needs of different market application fields.
2. Physicochemical properties of the hydroxypropyl methyl group
Physical properties It is a product that is soluble in water and most polar C and an appropriate proportion of ethanol / water, propanol / water, dichloroethane, but it is not soluble in ether, acetone, anhydrous ethanol, and can swell into a clarified or slightly turbid colloidal solution in cold water.Its aqueous solution has surface activity, high transparency, the performance is relatively stable.HPMC also has the properties of hot gel, its aqueous solution can form a gel dilution, and it is cold. Different specifications of product gel temperature is different.
The solubility varies with the viscosity, and the lower the viscosity, the greater the solubility.The properties of HPMC also vary naturally, and the pH value has no effect on the dissolution of HPMC in water.Granularity: 100 order pass rate is greater than 98.5%.Heack density: 0.25-0.70g/ (usually 0.4g /), 126-1.31.
Discolor temperature: 180-200℃, carbonization temperature: 280-300℃.The methoxy group value was 19.0% to 30.0%, and the hydroxypropyl value was 4% to 12%.Viscosity (22℃,2%5~200000mPa.s.Gel temperature (0.2%): 501 to 90℃.HPMC also has the characteristics of thickening capacity, salt discharge, pH stability, water retention, size stability, excellent film formation and a wide range of enzyme resistance, dispersion and bonding. 2.2 Chemical properties (1) Appearance: it is white or-like white powder. (2) Granularity: 100 entry pass rate is greater than 98.5%: 80 entry pass rate is 100%.Special size size 40~60 mesh. (3) The carbonization temperature: 280-300℃ (4) Hydroxypropyl methylcellulose. 25-0.70g/cm (usually around 0.5g / cm), ratio of 1.26-1.31. (5) Discolor temperature: 190-200℃ (6) Surface tension: the 2% aqueous solution is 42-56dyn / cm