10 questions about hydroxypropyl methylcellulose

10 questions about hydroxypropyl methylcellulose

1. What are the main uses of HPMC?

HPMC is widely used in building materials, coatings, synthetic resins, ceramics, medicine, food, textile, agriculture, cosmetics, tobacco and other industries. HPMC can be divided into industrial grade, food grade and pharmaceutical grade according to their uses.

2. Hydroxypropyl methylcellulose can be divided into several kinds, and what is the difference between their uses?

HPMC can be divided into instant type and heat-soluble type;

Instant products disperse rapidly in cold water and disappear in water. At this time, the liquid has no viscosity, because HPMC is only dispersed in water and has no real dissolution. About 2 minutes, the viscosity of the liquid gradually increases, forming a transparent white viscous colloid.

Heat soluble products, when meeting cold water, can disperse rapidly in hot water and disappear in hot water. When the temperature drops to a certain temperature, the viscosity slowly appears until transparent viscous colloid is formed.

3. How to judge the quality of HPMC simply and intuitively?

1) Although whiteness and whiteness can not determine whether HPMC is easy to use, and if whitening agent is added in the production process, it will affect its quality, but most good products have good whiteness.

2) Fineness: the fineness of HPMC is generally 80 mesh and 100 mesh, 120 mesh is less, the finer the fineness, the better.

3) Transmittance: after HPMC is put into water to form a transparent colloid, the greater the transmittance, the better, indicating that there is less insoluble matter.

4) Specific gravity: the greater the specific gravity, the heavier the better, the greater the ratio, generally because of the high content of hydroxypropyl in it, and the higher the content of hydroxypropyl, the better the water retention.

4. What are the dissolution methods of HPMC?

1) All models can be added to materials by dry mixing method;

2) When it needs to be directly added to the normal temperature water solution, it is better to use the cold water dispersion type, and the thickening can only take 10-90 minutes after adding (stirring and stirring)

3) Ordinary models are first dispersed with hot water and then mixed with cold water to dissolve;

4) In case of caking and wrapping during dissolution, it is due to insufficient mixing or the ordinary model is directly added to the cold water, so it should be stirred quickly.

5) If bubbles are produced during dissolution, they can be removed by standing for 2-12 hours (the specific time depends on the consistency of the solution) or by vacuuming and pressurizing, or by adding an appropriate amount of defoamer.

5. The amount of HPMC in putty powder?

The dosage of HPMC in practical application varies from place to place depending on climate, environment, temperature, quality of local lime, formula of putty powder and quality required by customers. Generally speaking, it is between 4 and 5 kg.

6. What is the appropriate viscosity of HPMC?

Putty powder is generally 100 thousand can be used, mortar requirements are higher, to 150000 is easy to use, and the more important role of HPMC is water retention, followed by thickening. In putty powder, as long as the water retention is good and the viscosity is lower (7-8), it is also OK. Of course, if the viscosity is higher, the relative water retention is better. When the viscosity exceeds 100000, the viscosity has little effect on the water retention.

7. What are the main raw materials of HPMC?

HPMC's main raw materials: refined cotton, methyl chloride, propylene oxide, and other raw materials, flake alkali, acid toluene.

8. What is the main role of hydroxypropyl methylcellulose in the application of putty powder and whether there is chemistry?

In the putty powder, it has three functions of thickening, water retention and construction. Thickening, cellulose can be thickened, play a role in suspension, keep the solution uniform up and down, anti sagging. Water retention: make the putty powder dry more slowly, and assist the reaction of gray calcium under the action of water. Application: cellulose has lubricating effect, which can make putty powder have good workability. HPMC did not participate in any chemical reaction, only played an auxiliary role.

9. HPMC is a non-ionic cellulose ether, so what is nonionic?

Generally speaking, inert substances do not participate in chemical reactions. CMC (carboxymethyl cellulose) belongs to cationic cellulose, so it will turn into bean curd residue when it encounters gray calcium.

10. What are the main technical indicators of HPMC?

Hydroxypropyl content, methyl content, viscosity, ash content, drying weight loss.