Factors affecting the purity of hydroxypropyl methylcellulose

Factors affecting the purity of hydroxypropyl methylcellulose

When we hear about hydroxypropyl methyl cellulose, many of us must feel very unfamiliar. Hydroxypropyl methyl cellulose is a semi-synthetic, inactive, viscoelastic polymer, often used in ophthalmology as a lubricant. , Or as an excipient or excipient in oral medicine, as a thickener and dispersant in the textile industry, the purity of hydroxypropyl methylcellulose in the construction of thermal insulation mortar directly affects the quality of construction. So what are the factors that affect the purity of hydroxypropyl methylcellulose?

In the production process of hydroxypropyl methyl cellulose, the residual oxygen in the reactor causes degradation of the hydroxypropyl methyl cellulose and a decrease in molecular weight. However, the residual oxygen is limited. It is not difficult to pick up the cracked molecules from the beginning. However, the saturation rate is also very much related to the hydroxypropyl content. Some factories only want to reduce costs and prices, but refuse to increase the hydroxypropyl content, so the quality cannot reach the level of similar products. The water retention rate of hydroxypropyl methylcellulose is closely related to the hydroxypropyl group, but it also determines its water retention rate, the effect of alkalization, and the share of methyl chloride and propylene oxide for the entire response process. , The concentration of alkali and the ratio of water to refined cotton determine the function of the product.

The quality of the material. The role of alkalization. The process ratio and the solvent ratio neutralize the effect of some Shijiazhuang hydroxypropyl methyl cellulose when it is made to dissolve, and it will be turbid like milk, some are milky white, some are yellow, and some are clear and bright. To deal with it, adjust from the above points. Sometimes acetic acid can seriously affect the light transmittance. It is best to use acetic acid after diluting. The biggest impact is whether the reverberation is evenly mixed and whether the system ratio is stable (the moisture content of some materials is unstable, such as the recovery of applied solvents). Many factors are influencing. If the equipment is stable and the operators are well trained, the production should be very stable. The light transmittance will not exceed the ±2% scale, and the uniformity of substitution of the substitution group must be controlled. Instead of being uniform, the light transmittance must be just fine.