What are the uses of hydroxypropyl methylcellulose?
Widely used in building materials, coatings, synthetic resins, ceramics, medicine, food, textile, agriculture, cosmetics, tobacco and other industries. HPMC can be divided into: construction grade, food grade and pharmaceutical grade according to the purpose. At present, most of the domestic products are construction grade. In the construction grade, the amount of putty powder is very large, about 90% is used for putty powder, and the rest is used for cement mortar and glue.

What are the methods of dissolving hydroxypropyl methyl fiber?
1. Hot water dissolving method: Since HPMC does not dissolve in hot water, HPMC can be uniformly dispersed in hot water at the initial stage, and then quickly dissolve when cooled.

2. Powder mixing method: Mix HPMC powder with a lot of other powdered chemical substances, fully mix it with a mixer, and then melt it with water, then HPMC can be melted at this time, and will not be collected in clusters, because each tiny In the small corner, there is only a little HPMC powder, and it will melt immediately when it meets water.

How to choose the viscosity of hydroxypropyl methylcellulose?
Choose different viscosities according to different applications, the application of putty powder: you can choose the viscosity of 100,000, the important thing is to keep the water better. Application of mortar: high requirements, high viscosity, choose viscosity 150,000. Application of glue: need instant products, high viscosity, choose viscosity 200,000.

How to identify the quality of hydroxypropyl methylcellulose?
Whiteness: Although whiteness does not determine whether HPMC is easy to use, and if a whitening agent is added in the production process, it will affect its quality. However, most of the good products have good whiteness.

Fineness: The fineness of HPMC is generally 80 mesh and 100 mesh, and 120 mesh is less. Most HPMC produced in Hebei is 80 mesh. The finer the fineness, the better.

Transmittance: Put hydroxypropyl methylcellulose (HPMC) in water to form a transparent colloid, and check its transmittance. The permeability of the vertical reactor is generally good, and the horizontal reactor is worse, but it cannot be said that the quality of the vertical reactor is better than that of the horizontal reactor, and there are many factors that determine the product quality.

Specific gravity: the larger the specific gravity, the heavier the better. The specific gravity is large, generally because the hydroxypropyl content in it is high, and the hydroxypropyl content is high, the water retention is better.

Relationship between Viscosity and Temperature of Hydroxypropyl Methylcellulose
The viscosity coefficient of HPMC is inversely proportional to the temperature, that is, as the temperature decreases, the viscosity coefficient increases, and its 2% solution is tested at a temperature of 20 degrees Celsius. In practical applications, in areas with a large temperature difference between summer and winter, it should be noted that a relatively lower viscosity is used in winter, which is more conducive to construction.

What is the role of HPMC in putty powder?
In the putty powder, HPMC plays three functions: thickening, water retention and construction.

Thickening: Cellulose can be thickened to suspend, keep the solution uniform and consistent, and resist sagging.

Water retention: Make the putty powder dry slowly, and assist the reaction of ash calcium under the action of water.

Construction: Cellulose has a lubricating effect, which can make the putty powder have good workability. HPMC does not participate in any chemical reaction and only plays an auxiliary role. Adding water to the putty powder and putting it on the wall is a chemical reaction. Because of the formation of new substances, take the putty powder on the wall off the wall, grind it into powder, and use it again. It will not work, because new substances (calcium carbonate) have been formed. ) up.

The main components of ash calcium powder are: a mixture of Ca(OH)2, CaO and a small amount of CaCO3, CaO+H2O=Ca(OH)2—Ca(OH)2+CO2=CaCO3↓+H2O Ash calcium in water and air Under the action of CO2, calcium carbonate is generated, while HPMC only retains water and assists the better reaction of ash calcium, and does not participate in any reaction itself.