Answer:1) whiteness: although whiteness can not determine whether HPMC is good, and if it is added in the production process of whitener, will affect its quality. However, good products are mostly white.
2) Fineness: HPMC fineness generally has 80 mesh and 100 mesh, 120 purpose is less, the finer the fineness is generally better.
3) transmittance: the hydroxypropyl methyl cellulose (HPMC) into the water, the formation of transparent colloid, see its transmittance, the greater the transmittance, the better, that less insoluble matter inside.
4) Proportion: the larger the proportion is better. It's usually because it's high in hydroxypropyl,
High hydroxypropyl content, water retention is better.
mortar adhesive additive. This can result in a longer lifespan for the building structure and reduce the need for frequent repairs or maintenance.

A study published in the Journal of Applied Toxicology evaluated the acute oral toxicity of HPMC in rats and found no side effects at doses up to 5000 mg/kg body weight (the highest dose tested). In addition, subchronic and chronic toxicity studies show no significant side effects in animals, even at high doses.