Quality of hydroxypropyl methyl cellulose

1. water solubility and thickening ability of hydroxypropyl methyl cellulose.

2. Soluble in organic solvents, due to the presence of a certain amount of hydrophobic methoxyl, this product can be soluble in organic solvents, but also can be soluble in water core organic mixed solvents.

3. Salt resistance: Since this product is a non-ionic and non-polymeric electrolyte, it is relatively stable in the aqueous solution of metal salts and organic electrolytes.

4. surface activity: aqueous solution has surface activity and therefore emulsification.

5. Thermal gelation, when heated to a certain temperature, the product's aqueous solution becomes opaque, production precipitation, so that the solution loses viscosity, but gradually cooled into the original solution state, the temperature of condensation and precipitation depends on the type of products, solution concentration heating rate.

6. Low ash content, because this product is non-ionic, in the preparation process can be effectively refined with hot water, so its ash content is very low.

7. PH stability, the viscosity of the product's aqueous solution is hardly affected by acid and alkali, this product in the PH3.0-11.0 range has relatively stable, water retention, because the product is hydrophilic and its aqueous solution is high viscosity, it is added to mortar, gypsum, paint, etc., to maintain high water retention in the product.

8. Shape retention: Compared with other water-soluble polymers, the aqueous solution of this product has special viscoelastic properties, and its addition helps to improve the Shape Invariance of extruded ceramic products.

9. Lubrication: Adding this product can reduce friction coefficient and improve lubricity of extruded ceramics and cement products.

10. film-forming: This product can produce strong, flexible, transparent lamellae with good grease resistance.

Two. Quality judgement of hydroxypropyl methyl cellulose

How can we judge the quality of hydroxypropyl methylcellulose? This is a matter of particular concern in the purchase of hydroxypropyl methylcellulose, the following to introduce the method, but intuitively we go to judge, for reference only.

1. Whiteness: The decisive factor determining the quality of HPMC can not be whiteness of course, some manufacturers in the production process with the addition of whitening agent in the case of quality can not be judged. However, the quality of HPMC whiteness is indeed good.

2, fineness: the degree of fineness of hydroxypropyl methylcellulose usually has 80 mesh and 100 mesh, and 120 purposes are not many. The finer the fineness, the better the quality in general.

3. Transmittance: Hydroxypropyl methylcellulose into water, in its formation of transparent colloid, to see his transmittance. The better the transmittance, the less insoluble substance. Vertical reactor production is better, horizontal reactor is worse, but this is not absolute, good product decisive factor is not this.

4, proportion: the greater the proportion, the heavier. The specific gravity, generally because the content of hydroxypropyl methyl is high, hydroxypropyl content is high, water retention is better.