Hydroxypropyl Methyl Cellulose

Chemical name: Hydroxypropyl Methyl Cellulose;

synonym: HPMC; E464; MHPC; Hydroxypropyl methylcellulose. Hydroxypropyl methyl cellulose,Hypromellose.

CAS no. : 9004-65-3

Formula:

Molecular weight: 86000.00000

 

HPMC Physical properties:

Appearance and properties: white or white fibrous or granular powder.

Density: 1.39 g/cm3.

Solubility: almost insoluble in anhydrous ethanol, ethyl ether and acetone; Swelling in cold water to clarify or slightly turbid colloidal solution.

Stability: solids are flammable and incompatible with strong oxidizing agents.

 

HPMC chemical properties

1. Appearance: white or white powder.

2. Granularity; 100 mesh pass rate is greater than 98.5%; 80 mesh pass rate is 100%. Sizes of special sizes 40 ~ 60.

3, carbonization temperature: 280-300 ℃

4. Visual density: 0.25-0.70g/cm(usually around 0.5g/cm), with a weight of 1.26-1.31.

5, color temperature: 190-200 ℃

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

7. Solubility: soluble in water and partial solvents, such as ethanol/water, propanol/water, etc. Aqueous solution has surface activity. High transparency, stable performance, different specifications of the products different gel temperature and solubility with viscosity change, lower viscosity, the greater the solubility, different specifications HPMC its performance has a certain difference, HPMC dissolved in the water is not affected by pH.

8. The content of HPMC decreased with the content of methoxy, increased gel point, decreased water solubility, and decreased surface activity.

9. HPMC also has the characteristics of thickening ability, salt tolerance low ash powder, pH stability, water retention, dimensional stability, excellent film forming, and extensive resistance to enzyme, dispersibility and adhesion.

 

HPMC Production method: 

Crush refined cotton and treated with alkali liquor in the 35-40 ℃ for half an hour, crushing, smash cellulose, in 35 ℃ suitable for aging, make the base fiber average degree of polymerization in the required range. And put alkali fiber into etherification kettle,  add epoxy propane and methyl chloride and 50-80 ℃ in etherification 5 h, the highest pressure 1.8 MPa. Then in 90 ℃ hot water adding suitable amount of hydrochloric acid and oxalic acid washing materials, volume expansion. Dehydrate with a centrifuge. Washing to neutral, when the material in water content below 60%, at 130 ℃ hot air flow drying to contain less than 5%. At last, the finished product was smashed through 20 mesh.

 

Solution dissolving method

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

2. When you need to directly add to the normal temperature water solution, it is better to use the cold water dispersive type, and after the addition, it can be thickened after 10 to 90 minutes.

3. After mixing the ordinary model with hot water, add cold water and stir to cool.

4. If there is a clumping phenomenon in the solution, it is because the agitation is not sufficient or the ordinary model is directly added to the cold water, and the reason should be quickly stirred.

5. If the bubbles are produced when dissolved, it can be left for 2-12 hours (depending on the consistency of the solution) or vacuum, pressure and other methods to remove them, and the appropriate amount of defoaming agent can be added.

 

The main application of HPMC:

1. Construction industry: as the water-retaining agent and retarding agent of cement mortar, the mortar has the pumping ability. Tile adhesive, gypsum plaster, wall putty powder or other building materials as adhesives to improve the applicability and prolong the open time. Use as tile adhesive, plastic adornment, still can reduce cement dosage. HPMC's water retention performance ensures that the slurry will not dry too fast and crack, enhancing the strength after hardening.

2. Ceramics manufacturing: widely used as adhesives in the manufacture of ceramic products.

3. Paints & Coating industry: as thickener, dispersant and stabilizer in the coating industry, it has good solubility in water or organic solvents. As a paint remover.

4. Ink printing: as thickener, dispersant and stabilizer in ink industry, it has good solubility in water or organic solvent.

5. Plastic: forming mould release agent, softener, lubricant, etc.

6. Polyvinyl chloride: as a dispersant in PVC production, the main additive of PVC is prepared by suspension polymerization.

7. Other: this product is widely used in leather, paper products, fruit and vegetable preservation and textile industry.

8. Pharmaceutical excipients: coating materials; Membrane material; Controlled speed polymer materials for sustained-release preparations; Stabilizing agent; Suspended aid; Tablet adhesive;

 

Exact application of HPMC：

Construction industry

1. Cement mortar: improve the dispersibility of cement and sand, greatly improve the plasticity and water retention of mortar, and improve the strength of cement.

2. Ceramic tile cement: to improve the plasticity, water retention and glue relay of ceramic tile mortar, to prevent powder.

3. Coating of fireproof materials such as asbestos: as suspension agent, fluidity improver, and improved adhesive relay on basement.

4. Gypsum coagulation paste: improve the water retention and processing, and improve the adhesion of the base.

5. Seam cement: added to cement paste used in gypsum board to improve liquidity and water retention.

6. Latex putty: improve the liquidity and water retention based on resin emulsion.

7. dry mix Mortar: as a substitute for the paste, it can improve the water retention and improve the adhesion of the base.

8. Coating: as a plasticizer for latex coating, it is useful for improving the operation performance and liquidity of the coating and putty powder.

9. Spraying coating: it has good effect to prevent the cement or latex coating from being sprayed to sink and improve fluidity and spray pattern.

10. Secondary products of cement and gypsum: as the cement and asbestos system, the pressure of the hard material is used to form the binder, which improves the fluidity, and can get the homogenous molding products.

11. Fiber wall: because of the anti-bacterial action of the anti-enzyme, as the adhesive of sand wall is effective.

12. Other: a bubble retention agent that can be used as a thin paste sand mortar and a muddy water operator (PC version).

The chemical industry

1, vinyl chloride, vinyl polymerization: as a polymerization suspension stabilizer and dispersant, with vinyl alcohol (PVA), hydroxypropyl cellulose (HPC) and use, can control the grain shape and the distribution of the particles.

2. Adhesive: as the adhesive of wall paper, substitute starch usually can be used with vinyl acetate latex paint.

3. Pesticides: added to insecticide, herbicide, can improve the adhesion effect of spraying.

4. Latex: emulsifying stabilizer for asphalt emulsion, thickening agent for styrene butadiene rubber (SBR) latex.

5. Adhesive: as the forming adhesive for pencils and crayons.

The cosmetics industry

1. Shampoo: increase the viscosity of shampoo, washing agent, detergent and air bubble stability.

2. Toothpaste: improve the fluidity of toothpaste.

The food industry

1. Canned citrus: to prevent the whitening and metamorphosis in preservation.

2. Cold fruit products: added to the fruit syrup, ice medium, to make the taste better.

3. Sauce: emulsifying stabilizer or thickener as a sauce or tomato sauce.

4. Cold water coating: for frozen fish storage, it can prevent discoloration and quality, and after coating with methyl cellulose or hydroxypropyl methyl cellulose solution, freeze the ice.

5. The adhesive of the tablet: as the forming adhesive for tablets and pills, the adhesive "at the same time collapse" (rapid dissolution of the collapse) is good.

Pharmaceutical industry

1. Coating: make a solution of organic solvent or water solution to the pill, especially spray coating for granules.

2. Relief agent: 2 to 3 grams per day, 1 to 2 grams per time, and it will be effective in 4 to 5 days.

3. Eye medicine: because the osmotic pressure of methylcellulose aqueous solution is the same as that of tears, it can be used as a lubricant to contact lens of the eyeball.

4. Gelatine: base material for external use or ointment.

5. Impregnating agent: as a thickener, water retention agent.

Furnace industry

1. Electronic materials: as the ceramic electric tightener, the adhesive for the extruding of the ferrite alumina magnet can be used with 1.2- propylene glycol.

2. Glazing agent: it is used as the glaze medicine of ceramics and the combination with enamel, which can improve the adhesion and processing.

3. Refractory mortar: it can improve the plasticity and water retention in firebrick mortar or pouring type furnace.

Other industries

1. Fiber: used as printing dye paste for pigment, boron soil, salt base dyes and textile dyes. In addition, in the corrugated processing of kapok, it can be used with heat hardened resin.

2. Paper: it is used in the leather surface of carbon paper and oil resistance processing.

3. Leather: used as the last lubricant or disposable adhesive.

4. Water-based ink: added in water-based ink and ink, as thickener and film agent.

5. Tobacco: as the adhesive for reproducing tobacco.