Do you know "Hydroxypropyl Methyl Cellulose"?

One: Variety information

English name: HydroxyPropylMethylCellulose

English alias: HPMC

Two: main purpose

1. Construction industry: As a water-retaining agent and retarder of cement mortar, it can make the mortar pumpable. Used as a binder in plaster, plaster, putty powder or other building materials to improve spreadability and prolong work time. It can be used as paste tile, marble, plastic decoration, paste reinforcement, and can also reduce the amount of cement. The water-retaining performance of HPMC prevents the slurry from cracking due to drying too quickly after application, and enhances the strength after hardening.

2. Ceramic manufacturing industry: It is widely used as a binder in the manufacture of ceramic products.

3. Coating industry: It is used as a thickener, dispersant and stabilizer in the coating industry, and has good compatibility in water or organic solvents. As a paint remover.

4. Ink printing: It is used as a thickener, dispersant and stabilizer in the ink industry, and has good compatibility in water or organic solvents.

5. Plastics: used as forming release agent, softener, lubricant, etc.

6. Polyvinyl chloride: It is used as a dispersant in the production of polyvinyl chloride, and it is the main auxiliary agent for preparing PVC by suspension polymerization.

7. Others: This product is also widely used in leather, paper products, fruit and vegetable preservation and textile industries.

8. Pharmaceutical industry: coating materials; film materials; rate-controlling polymer materials for sustained-release preparations; stabilizers; suspending agents; tablet adhesives; viscosity-increasing agents

Three: physical properties

Soluble in water and most polar c and appropriate proportions of ethanol/water, propanol/water, dichloroethane, etc., insoluble in ether, acetone, absolute ethanol, and swells into a clear or slightly cloudy colloid in cold water solution. The aqueous solution has surface activity, high transparency and stable performance. HPMC has the property of thermal gelation. The product aqueous solution is heated to form a gel and precipitates, and then dissolves after cooling. The gelation temperature of different specifications is different. Solubility varies with viscosity. The lower the viscosity, the greater the solubility. Different specifications of HPMC have certain differences in their properties, and the dissolution of HPMC in water is not affected by the pH value. Particle size: 100 mesh pass rate is greater than 98.5%. Bulk density: 0.25-0.70g/ (usually about 0.4g/), specific gravity 1.26-1.31. Discoloration temperature: 180-200°C, carbonization temperature: 280-300°C. The methoxyl value ranges from 19.0% to 30.0%, and the hydroxypropyl value ranges from 4% to 12%. Viscosity (22℃, 2%) 5～200000mPa.s. The gel temperature (0.2%) is 50-90°C. HPMC has the characteristics of thickening ability, salt discharge, PH stability, water retention, dimensional stability, excellent film-forming property, and wide range of enzyme resistance, dispersibility and cohesiveness.

Four:Chemical Properties

1. Appearance: white or off-white powder.

2. Particle size; the pass rate of 100 mesh is greater than 98.5%; the pass rate of 80 mesh is 100%. Particle size of special specifications is 40-60 mesh.

3. Carbonization temperature: 280-300°C

4. Apparent density: 0.25-0.70g/cm (usually around 0.5g/cm), specific gravity 1.26-1.31.

5. Discoloration temperature: 190-200°C

6. Surface tension: 2% aqueous solution is 42-56dyn/cm.

7. Solubility: Soluble in water and some solvents, such as ethanol/water, propanol/water, etc. in appropriate proportions. Aqueous solutions are surface active. High transparency, stable performance, different specifications of products have different gel temperatures, solubility changes with viscosity, the lower the viscosity, the greater the solubility, different specifications of HPMC have certain differences in performance, and the dissolution of HPMC in water is not affected by pH.

8. With the reduction of methoxyl content, the gel point increases, the water solubility of HPMC decreases, and the surface activity also decreases.

9. HPMC also has the characteristics of thickening ability, salt resistance, low ash powder, pH stability, water retention, dimensional stability, excellent film-forming property, and wide range of enzyme resistance, dispersibility and cohesiveness.

Five: Item properties

Soluble in water and most polar c and appropriate proportions of ethanol/water, propanol/water, dichloroethane, etc., insoluble in ether, acetone, absolute ethanol, and swells into a clear or slightly cloudy colloid in cold water solution. The aqueous solution has surface activity, high transparency and stable performance. HPMC has the property of thermal gelation. The product aqueous solution is heated to form a gel and precipitates, and then dissolves after cooling. The gelation temperature of different specifications is different. Solubility varies with viscosity. The lower the viscosity, the greater the solubility. Different specifications of HPMC have certain differences in their properties, and the dissolution of HPMC in water is not affected by the pH value. Particle size: 100 mesh pass rate is greater than 98.5%. Bulk density: 0.25-0.70g/ (usually around 0.4g/), specific gravity 1.26-1.31. Discoloration temperature: 180-200°C, carbonization temperature: 280-300°C. The methoxyl value ranges from 19.0% to 30.0%, and the hydroxypropyl value ranges from 4% to 12%. Viscosity (22°C, 2%) 5～200000mPa .s. The gel temperature (0.2%) is 50-90°C. HPMC has the characteristics of thickening ability, salt discharge, PH stability, water retention, dimensional stability, excellent film-forming property, and wide range of enzyme resistance, dispersibility and cohesiveness.

Six: Synthesis method

Treat the refined cotton cellulose with lye at 35-40°C for half an hour, press it, crush the cellulose, and age it properly at 35°C, so that the average degree of polymerization of the obtained alkali fiber is within the required range. Put the alkali fiber into the etherification kettle, add propylene oxide and methyl chloride in sequence, and etherify at 50-80°C for 5 hours, the maximum pressure is about 1.8MPa. Then add appropriate amount of hydrochloric acid and oxalic acid to the hot water at 90°C to wash the material to expand the volume. Dehydrate in a centrifuge. Wash until neutral, and when the water content in the material is lower than 60%, dry it with a hot air flow at 130°C to a content of less than 5%. Finally crushed through a 20-mesh sieve to obtain the finished product.

Seven: Dissolving method

1. All models can be added to the material by dry mixing method;

2. When it needs to be directly added to the normal temperature aqueous solution, it is best to use cold water dispersion type, and it usually takes 10-90 minutes to thicken after adding;

3. For common models, stir and disperse with hot water first, then add cold water to stir and cool to dissolve;

4. If agglomeration occurs when dissolving, it is because the stirring is insufficient or the ordinary model is directly added to cold water. At this time, it should be stirred quickly.

5. If bubbles are generated during dissolution, they can be left to stand for 2-12 hours (the specific time is determined by the consistency of the solution) or removed by vacuuming, pressurizing, etc., and an appropriate amount of defoaming agent can also be added.

Eight: safety performance

health hazard

This product is safe and non-toxic, can be used as a food additive, has no heat, and has no irritation to the skin and mucous membranes. It is generally considered safe (FDA1985), with a daily allowable intake of 25mg/kg (FAO/WHO1985), and protective equipment should be worn during operation.

environmental impact

Avoid random throwing of dust to cause air pollution.

Physical and chemical hazards: Avoid contact with fire sources, and avoid forming a large amount of dust in a closed environment to prevent explosive hazards.

Storage matters

Pay attention to sun, rain and moisture, avoid direct sunlight, and store in a sealed dry place.

security terms

S24/25 Avoid contact with skin and eyes.

Avoid contact with skin and eyes.

Nine: Application field

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.

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.

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.

Food industry

1. Canned citrus: prevent whitening and deterioration due to the decomposition of citrus during preservation to achieve freshness preservation.

2. Cold fruit products: add to sherbet, ice, etc. to make the taste better.

3. Seasoning sauce: used as emulsification stabilizer or thickener for sauce and tomato sauce.

4. Cold water coating and glazing: used for frozen fish storage, which can prevent discoloration and quality reduction. After coating with methyl cellulose or hydroxypropyl methyl cellulose aqueous solution, freeze it on ice.

5. Adhesive for tablets: As a forming adhesive for tablets and granules, it has good bonding "simultaneous collapse" (rapidly melts and collapses when taken).

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 and water retention agent.

Kiln industry

1. Electronic material: as a binder for extrusion molding of ceramic electrical seals and ferrite bauxite magnets, it can be used together with 1.2-propylene glycol.

2. Glaze: used as glaze for ceramics and in combination with enamel paint, it can improve bonding and processability.

3. Refractory mortar: Added to refractory brick mortar or pouring furnace materials, it can improve plasticity and water retention.

Other industries

1. Fiber: Used as printing dye paste for pigments, boron dyes, basic dyes, and textile dyes. In addition, it can be used together with thermosetting resins in kapok corrugation processing.

2. Paper: used for leather surface gluing and oil-resistant processing of carbon paper.

3. Leather: used as final lubrication or one-time adhesive.

4. Water-based ink: Added to water-based ink and ink, as a thickener and film-forming agent.

5. Tobacco: as a binder for regenerated tobacco.