- July 2, 2021
- Posted by: admin
- Category: News
The choice of hydroxypropyl methylcellulose HPMC for construction mainly considers viscosity and light transmittance. Hydroxypropyl methylcellulose HPMC mainly has three kinds of viscosity, namely HPMC-100000, HPMC-150000, HPMC-200000 viscosity, SLEOCHEM Is a professional manufacturer of cellulose, also has low viscosity cellulose; hydroxypropyl methylcellulose HPMC light transmittance can reflect the quality and transparency of cellulose, so we have to affect the viscosity of hydroxypropyl methylcellulose and The factors of light transmittance are known.
Factors affecting the viscosity of hydroxypropyl methylcellulose HPMC
ydroxypropyl methylcellulose HPMC is produced by a series of etherification reactions in production, but only by vacuum and nitrogen replacement is the production of cellulose with a very high viscosity. Generally, the production of high-viscosity cellulose in China is uncontrollable, but if a trace oxygen meter is installed in the kettle, the viscosity of the cellulose production can be artificially controlled. In addition, considering the replacement rate of nitrogen, it is very easy to produce a high-viscosity product at the same time as the system is airtight. Of course, the degree of polymerization of refined cotton is also crucial. If it doesn’t work, use a hydrophobic association to do it. The choice of what kind of associative agent has a great influence on the performance of the final product. The residual oxygen in the reactor causes degradation of the cellulose, and the molecular weight is lowered, but the residual oxygen is limited, and it is not difficult to make the high viscosity by reconnecting the broken molecules. However, the water saturation rate is also closely related to the content of hydroxypropyl groups. The hydroxypropyl group content is high, and the water retention effect of the product is good. The water retention rate of the product is closely related to the hydroxypropyl group, but it also determines its water retention rate, the effect of alkalization, the ratio of methyl chloride to propylene oxide, the concentration of alkali and water for the entire reaction process. The ratio to refined cotton determines the performance of the product. Therefore, the water retention and hydroxypropyl content of hydroxypropyl methylcellulose have a great relationship with the specific gravity of the molecular weight. Therefore, we should use a product with a high specific gravity and a high hydroxypropyl content when selecting a cellulose product.
factors affecting the transmittance of hydroxypropyl methyl cellulose
1, Quality of raw materials: selection of raw materials such as refined cotton, propylene oxide and methyl chloride.
2, The effect of alkalization.
3,The process ratio: the axe production, dissolution quickly, after washing three times in addition to the sewage washing process.
4, the ratio of solvent: raw materials and aqueous solution reasonable blending experiments.
5, the effect of neutralization: After the dissolution test of hydroxypropyl methylcellulose, some products are very turbid like milk after dissolution, some are milky white, some are yellow, some are clear and transparent… sometimes acetic acid can Severely affect the light transmittance, acetic acid is best used after dilution, the maximum effect is whether the stirring of the reaction is uniform, whether the system ratio is stable (some materials have moisture, the content is unstable, such as the solvent used for recycling), in fact, many factors are affecting. The equipment should be stable if the equipment is stable and the operator is skilled. The light transmittance does not exceed ±2%, and the substitution uniformity of the substituent group is controlled. Instead of uniformity, the light transmittance is definitely good. The light transmittance is good, and the aqueous solution of hydroxypropyl methylcellulose is very transparent and the transmittance is very good.
We supply different types of HPMC acted as building raw material for different application,