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What is hydroxypropyl methyl cellulose (HPMC)?

Views: 7     Author: Site Editor     Publish Time: 2022-03-22      Origin: Site

What is hydroxypropyl methyl cellulose (HPMC)?

Hydroxypropyl methyl cellulose (HPMC) is a natural polymer material as raw material, through a series of chemical processing and non-ionic cellulose ether.

It contains almost all the properties of methyl cellulose (MC) and is your additive for producing high quality building materials. In order to satisfy the demand of green environmental protection, I plant for the building materials industry, specially in producing thousand embellish brand products, with high water retention performance, good dispersion, good fineness, good workability, easy to dissolve the characteristics such as: applicable to dry powder mortar building materials, external water resistant putty powder (cream), binder, gap filling agent, interface agent, water-based paint, self-leveling agent such as new building materials. In the production of building materials, cellulose ether is an indispensable additive. After adding HPMC, the following performance can be improved:

1, water retention - enhance water retention, improve cement, gypsum building materials too fast drying and insufficient hydration caused by hardening, cracking and other phenomena.

2. Workability -- increase the plasticity of mortar, improve the industriality of construction coating and improve work efficiency;

3, cohesiveness - due to the improved plasticity of mortar, so that it can better bond the substrate and the adhesive;

4, anti-slip - because of its thickening effect, so can prevent the construction of mortar and by the phenomenon of slippage.

II. Molecular composition and structural formula


III. physical and chemical properties:

1, appearance: HPMC is white or white fiber granular powder, odorless.

2, soluble: HPMC in anhydrous ethanol, ether, acetone is almost insoluble, dissolved in cold water into a clear or slightly turbidglue. HPMC can be dissolved in some organic solvents, also can be dissolved in a mixture of water and organic solvents.

3, particle size: 100 mesh pass rate ≥98.5%, 80 mesh pass rate 100%.

4, apparent density: 0.30-0.70g/cm3, density 1.26-1.31g/cm3.

V. Product features:

1, salt resistance: HPMC non-ionic cellulose ether, and not polyelectrolyte, so in the presence of metal salt or organic electrolyte, more stable in aqueous solution, but excess electrolyte, can cause gel or precipitation.

2, surface activity: HPMC aqueous solution has surface activity function, can be used as a colloidal protective agent, emulsifier and dispersant.

3, hot gel: HPMC aqueous solution when heated to a certain temperature, become opaque, gel, precipitation, but in the continuous cooling, it is restored to the original solution state, and the temperature of this gel and precipitation mainly depends on their type, concentration and heat rate.

4, ph-stability: THE viscosity of HPMC aqueous solution is almost not affected by acid or alkali, and the PH value is relatively stable in the range of 3.0-11.0.

5, water retention: HPMC is a highly efficient water retention agent, has a wide range of applications in ceramics, building materials and many other aspects.

6, adhesion: HPMC as a kind of high and new binder, used in pigment, paper, tobacco products and ceramic products.

Six, dissolution method:

1, hot water method: add the required amount of 1/3 or 2/3 water in the container, and heat to more than 80 deG C, because HPMC does not dissolve in hot water. Thus, early HPMC can be evenly dispersed in hot water, and then add the remaining amount of cold water or ice water to the hot water slurry, after stirring, cooling the mixture.

2, powder mixing method: HPMC powder and equal or greater amount of other powdery ingredients, through dry mixing to fully dispersed, then add water to dissolve, at this time HPMC can be dissolved, and not condensed.

3, organic solvent wetting method: HPMC with organic solvents, such as ethanol, ethylene glycol or oil dispersed or wet, and then add water to dissolve, then HPMC can also be smoothly dissolved.

Note: After surface treatment HPMC can be first wet with cold water, such as ammonia or alkali water to adjust the PH to 8-10 can form viscosity.

Seven, main uses:

HPMC can be used as thickener, dispersant, emulsifier and film forming agent. Its industrial grade products can be used in daily chemicals, synthetic resins, construction and coatings.

1. Suspension polymerization:

In the production of synthetic resins, such as polyvinyl chloride (PVC), polyvinylidene chloride and other copolymers, suspension polymerization is most often used and it is necessary to stabilize hydrophobic units suspended in water. HPMC products as water-soluble polymers have excellent surface activity, but also plays a role of colloidal protective agent, it can effectively prevent the polymerization of particles condensation. Furthermore, although HPMC is a water-soluble polymer, it is slightly soluble in hydrophobic units and increases the unit porosity for producing polymer particles, and it provides the polymer with a good ability to remove residual units and improve the absorption of plasticizers.

2. In the formula of building materials, it can be used

1) Water resistant putty powder

2) Cement mortar

3) cement - based brick, tile and base brick bonding

4) Plasterboard based plaster