What is HPMC? HPMC or Hydroxypropyl methylcellulose (INN name: Hypromellose), also simplified as hydroxypropyl methylcellulose (HPMC), is a kind of non-ionic cellulose mixed ether. It is a semi-synthetic, inactive, viscoelastic polymer. Hydroxypropyl methylcellulose is widely used in construction, food, medicine, and other industries.
HPMC CAS No. 9004-65-3
Molecular weight: 86000.00000
Appearance and Properties: White or quasi-white fibrous or granular powder
Density: 1.39 g/cm 3
Solubility: Almost insoluble in absolute ethanol, ether, and acetone; swelling in cold water into a clear or slightly turbid colloidal solution
Stability: Solids are flammable and incompatible with strong oxidants.
1. Appearance: White or similar white powder.
2. Particle size; 100 mesh pass rate is more than 98.5%; 80 mesh pass rate is 100%. Particle sizes of special specifications ranged from 40 to 60 meshes.
3. Carbonization temperature: 280-300 ℃
4. Visual density: 0.25-0.70g/cm (usually about 0.5g/cm), specific gravity 1.26-1.31.
5. Discoloration temperature: 190-200 ℃
6. Surface tension: 2% aqueous solution is 42-56 dyn/cm.
7. Solubility: Soluble in water and some solvents, such as the appropriate proportion of ethanol/water, propanol/water, etc. The aqueous solution has surface activity. With high transparency and stable performance, the gel temperature of different specifications is different, the solubility changes with viscosity, the viscosity is lower and the solubility is greater. The performance of HPMC with different specifications has a certain difference. The dissolution of HPMC in water is not affected by the PH value.
8, HPMC decreases with the decrease of methoxy content, the increase of gel point, the decrease of water solubility, and the decrease of surface activity.
- HPMC also has the characteristics of thickening ability, salt-resistant low ash powder, pH stability, water retention capacity, dimensional stability, excellent film-forming ability, and extensive enzyme resistance, dispersibility, and cohesion.
What is HPMC Production method：
The refined cotton cellulose was treated with alkali solution at 35-40 ~C for half an hour, pressed, crushed and aged at 35 ~C, so that the average degree of polymerization of the obtained alkali fibers was within the required range. Alkali fibers were put into the etherification kettle, then propylene oxide and chloromethane were added in turn, and etherified at 50-80 (?) C for 5 hours. The maximum pressure was about 1.8 MPa. Then add the appropriate amount of hydrochloric acid and oxalic acid washing material in hot water at 90 ~C to make the volume expand. Dehydration by centrifuge. Wash to neutral, when the moisture content in the material is less than 60%, dry to below 5% by hot air flow at 130 C. Finally, the finished product was obtained by crushing 20 meshes and sieving.
1. All models can be added to the material by a dry mixing method.
2. When it needs to be added directly to the normal temperature water solution, it is better to use the cold water dispersion type, which can only be thickened in 10-90 minutes.
3. Ordinary models are first dispersed by hot water stirring, then cooled by cold water stirring to dissolve.
4. If the phenomenon of agglomeration and encapsulation occurs during dissolution, it is due to insufficient stirring or the direct addition of ordinary models to cold water. At this time, rapid stirring should be adopted.
5. If bubbles occur during dissolution, they can be removed by standing for 2-12 hours (the specific time depends on the consistency of the solution) or by vacuum or pressurization, or by adding appropriate defoamers.
What is HPMC Used for:
1. Construction industry: As a water-retaining agent and retarder of cement mortar, it makes the mortar pumpable. Use plaster, gypsum, putty powder or other building materials as adhesives to improve the applicability and prolong the operation time. It can be used to paste ceramic tile, marble, plastic decoration, paste reinforcing agent, and reduce the amount of cement. The water-retaining property of HPMC prevents the slurry from cracking due to drying too fast after smearing and enhances the strength after hardening.
2. Ceramic manufacturing industry: widely used as adhesives in the manufacture of ceramic products.
3. Coatings industry: As a thickener, dispersant and stabilizer in the coating industry, it has good solubility in water or organic solvents. As paint remover.
4. Ink printing: As a thickener, dispersant and stabilizer in the ink industry, it has good solubility in water or organic solvents.
5. Plastics: as forming release agent, softener, lubricant, etc.
6. Polyvinyl chloride: As dispersant in the production of polyvinyl chloride, it is the main assistant in the preparation of PVC by suspension polymerization.
7. Others: This product is also widely used in leather, paper products, fruit and vegetable preservation, and textile industry.
8. Pharmaceutical Industry: Coating Material; Membrane Material; Speed-Controlled Polymer Material for Sustained Release Agents; Stabilizer; Suspension Aid; Tablet Adhesive; Viscosifier