What is hydroxypropyl methyl cellulose?

Introduction to Hydroxypropyl Methyl Cellulose
Hydroxypropyl methylcellulose, also known as hypromellose and HPMC cellulose hydroxypropyl methyl ether, is made of highly pure cotton cellulose as raw material, which is specially etherified under alkaline conditions. HPMC is a white powder, tasteless, odorless, non-toxic, completely unchanged in the human body and excreted from the body. The product is soluble in water, but insoluble in hot water. The aqueous solution is a colorless transparent viscous substance. HPMC has excellent thickening, emulsifying, film-forming, dispersing, protective colloid, moisture retention, adhesion, acid and alkali resistance, enzyme resistance and other properties, and is widely used in construction, coatings, medicine, food, textiles, oil fields, cosmetics, washing Agents, ceramics, inks and chemical polymerization processes.

1. The low calcium content of gray calcium and the inappropriate ratio of CaO and Ca(OH)2 in gray calcium will cause powder loss. If it has something to do with HPMC, then if the water retention of HPMC is poor, it will also cause powder loss. Is the powder loss of putty powder related to hydroxypropyl methylcellulose? The powder loss of putty powder is mainly related to the quality of ash calcium, and has little to do with HPMC.

2. The most important function of hydroxypropyl methylcellulose is water retention, followed by thickening. In the putty powder, as long as the water retention is good and the viscosity is low (70,000-80,000), it is also possible. Of course, the higher the viscosity, the better the relative water retention. When the viscosity exceeds 100,000, the viscosity will affect the water retention. Not much anymore.

What is the viscosity of hydroxypropyl methylcellulose (HPMC)?

Putty powder is generally 100,000 yuan, and the requirements for mortar are higher, and 150,000 yuan is required for easy use.

3. What are the main raw materials of hydroxypropyl methylcellulose? The main raw materials of hydroxypropyl methylcellulose (HPMC): refined cotton, methyl chloride, propylene oxide, and other raw materials, caustic soda, acid, Toluene, isopropanol, etc.

4. What is the reason for the smell of hydroxypropyl methylcellulose? The hydroxypropyl methylcellulose produced by the solvent method uses toluene and isopropanol as solvents. If the washing is not very good, there will be some residual smell .

5. Hydroxypropyl methylcellulose: The one with high hydroxypropyl content is generally better in water retention. The one with high viscosity has better water retention, relatively (not absolutely), and the one with high viscosity is better used in cement mortar. What are the main technical indicators? Hydroxypropyl content and viscosity, most users are concerned about these two indicators.

Is the phenomenon of efflorescence in mortar related to hydroxypropyl methylcellulose?

Some time ago, a customer said that the product had efflorescence, and he was doing spraying. Shotcrete: The main function is to cover the back, roughen, and increase the adhesion between the wall and the surface material. Use very little, just spray a thin layer on the wall. Here is a picture of the efflorescence phenomenon that a customer sent me: Picture My first reaction is that it is definitely not the cause of hydroxypropyl methylcellulose, because hydroxypropyl methylcellulose is not compatible with anything in the gunpowder reacted. And the phenomenon of efflorescence is: ordinary concrete is silicate, when it encounters air or moisture in the wall, the silicate ion undergoes a hydrolysis reaction, and the generated hydroxide combines with metal ions to form a hydroxide with low solubility (chemical properties Alkaline), when the temperature rises, the water vapor evaporates, and the hydroxide is precipitated from the wall. With the gradual evaporation of the water, the hydroxide is precipitated on the surface of the concrete cement, which accumulates over time, making the original decorative When the paint or paint is lifted up and no longer adheres to the wall, whitening, peeling, and peeling will occur. This process is called “pan-alkali”. So it’s not the ubiquinol caused by hydroxypropyl methylcellulose

The customer also mentioned a phenomenon: the sprayed grout he made will have pan-alkaline phenomenon on the concrete wall, but will not appear on the fired brick wall, which shows that the silicon in the cement used on the concrete wall Salts (strongly alkaline salts) are too high. Efflorescence caused by evaporation of water used in spray grouting. However, there is no silicate on the fired brick wall and no efflorescence will occur. So the phenomenon of efflorescence has nothing to do with spraying.

Solution:

1. The silicate content of base concrete cement is reduced.

2. Use anti-alkali back coating agent, the solution penetrates into the stone to block the capillary, so that water, Ca(OH)2, salt and other substances cannot penetrate, and cut off the way of pan-alkaline phenomenon.

3. Prevent water intrusion, and do not sprinkle a lot of water before construction.

Treatment of pan-alkaline phenomenon:
The stone efflorescence cleaning agent on the market can be used. This cleaning agent is a colorless translucent liquid made of non-ionic surfactants and solvents. It has a certain effect on the cleaning of some natural stone surfaces. But before use, be sure to make a small sample test block to test the effect and decide whether to use it.

Application of Cellulose in Construction Industry

1. Cement mortar: Improve the dispersion of cement-sand, greatly improve the plasticity and water retention of mortar, have an effect on preventing cracks, and enhance the strength of cement.
2. Tile cement: improve the plasticity and water retention of pressed tile mortar, improve the adhesion of tiles, and prevent chalking.
3. Coating of refractory materials such as asbestos: as a suspending agent, fluidity improving agent, and also improves the bonding force to the substrate.
4. Gypsum coagulation slurry: improve water retention and processability, and improve adhesion to the substrate.
5. Joint cement: added to joint cement for gypsum board to improve fluidity and water retention.
6. Latex putty: improve the fluidity and water retention of resin latex-based putty.
7. Stucco: As a paste to replace natural products, it can improve water retention and improve the bonding force with the substrate.
8. Coatings: As a plasticizer for latex coatings, it can improve the operability and fluidity of coatings and putty powders.
9. Spraying paint: It has good effect on preventing the sinking of cement or latex spraying materials and fillers and improving fluidity and spray pattern.
10. Secondary products of cement and gypsum: used as an extrusion molding binder for cement-asbestos and other hydraulic substances to improve fluidity and obtain uniform molded products.
11. Fiber wall: Due to the anti-enzyme and anti-bacterial effect, it is effective as a binder for sand walls.
12. Others: It can be used as air bubble retaining agent (PC version) for thin clay sand mortar and mud hydraulic operator.

Applications in the chemical industry
1. Polymerization of vinyl chloride and vinylidene: As a suspension stabilizer and dispersant during polymerization, it can be used together with vinyl alcohol (PVA) hydroxypropyl cellulose (HPC) to control particle shape and particle distribution.
2. Adhesive: As a adhesive for wallpaper, it can be used together with vinyl acetate latex paint instead of starch.
3. Pesticides: Added to insecticides and herbicides, it can improve the adhesion effect when spraying.
4. Latex: Emulsion stabilizer for asphalt latex, thickener for styrene-butadiene rubber (SBR) latex.
5. Binder: as a forming binder for pencils and crayons.

Applications in the cosmetics industry
1. Shampoo: Improve the viscosity of shampoo, detergent, and cleaning agent and the stability of bubbles.
2. Toothpaste: Improve the fluidity of toothpaste.

Applications in the pharmaceutical industry
1. Encapsulation: The encapsulation agent is made into an organic solvent solution or an aqueous solution for drug administration, especially for spray encapsulation of the prepared granules.
2. Slow down agent: 2-3 grams per day, 1-2G each time, the effect will appear in 4-5 days.
3. Eye drops: Since the osmotic pressure of methylcellulose aqueous solution is the same as that of tears, it is less irritating to the eyes, so it is added to eye drops as a lubricant for contacting the eyeball lens.
4. Jelly: as the base material of jelly-like external medicine or ointment.
5. Dipping medicine: as a thickener, water retention agent