hydroxypropyl methylcellulose HPMC in Plastering MortarFebruary 2nd 2023
The light transmittance of hydroxypropyl methyl cellulose is mainly affected by the following points:
First, the quality of raw materials.
Two, the effect of alkalization.
Three, process ratio
Four, the ratio of solvent
Five, the effect of neutralization
Some products are made to dissolve after the elephant added milk is very turbid, have a plenty of milky white, have a plenty of yellow, have a plenty of clear and transparent. Want to solve from the above adjustment.
Sometimes acetic acid can seriously affect the transmittance. It is best to dilute acetic acid and use it, but the biggest influence is whether the reaction is even and the system ratio is stable (some materials have unstable moisture and content, such as recycling the applied solvent). In fact, many factors are influencing it. Production should be stable if the equipment is stable and the operator is well trained. The transmittance should not exceed ±2%, and the uniformity of substituting groups should be well controlled.
Instead of uniformity, transmittance is definitely good
Factors affecting viscosity of KimaCell HPMC hydroxypropyl methyl cellulose
High viscosity KimaCell hydroxypropyl methyl cellulose cannot be produced by vacuuming and nitrogen replacement alone. Generally, the production of high viscosity cellulose in China cannot be controlled. However, if a micro oxygen measuring instrument can be installed in the kettle, its viscosity production can be artificially controlled. In addition, considering the replacement speed of nitrogen, it is very easy to produce high viscosity products with good air tightness. Of course, the degree of polymerization of refined cotton is also very important. If that doesn’t work then do it by hydrophobic association. There are domestic associations in this respect. What kind of association agent to choose the final product performance is a great influence.
Residual oxygen in the reaction kettle leads to degradation of cellulose and reduction of molecular weight, but the residual oxygen is limited. As long as the broken molecules are re-connected, it is not difficult to make high viscosity. But the saturation rate is also very related to the content of hydroxypropyl, some factories just want to reduce the cost and price, do not want to improve the content of hydroxypropyl, so the quality can not reach the level of similar products outside.
The water retention rate of the product is greatly related to hydroxypropyl, but for the whole reaction process also determines its water retention rate, the effect of alkalization, the ratio of chloromethane and propylene oxide, the concentration of alkali and the ratio of water and refined cotton determine the performance of the product.