Here are a few tips to tell the difference between real and fake HPMC

Now, with national demand for building energy conservation and environmental protection, construction additives hydroxypropyl methyl cellulose, got the trust of more and more of the builder, the current domestic hydroxypropyl methyl cellulose quality good and bad are intermingled, price six to one, cause the water retention of the product, such as bonding performance is greatly reduced, many construction quality problem, made it difficult for customers to make the right choice.

The differences between pure HPMC and adulterated HPMC are as follows:

1. The visual state of pure HPMC is fluffy and the packing density is small. The range is 0.3-0.4g/ mL; Adulterated HPMC liquidity is better, feel more heavy, and the appearance of the genuine there are obvious differences.

2. Pure HPMC aqueous solution clarification, high light transmittance, water retention rate ≥97%; Adulterated HPMC aqueous solution is turbid, water retention rate is difficult to reach 80%.

3. Pure HPMC should not smell ammonia, starch and alcohol; Adulterated HPMC can often smell all kinds of taste, even if tasteless, will feel heavy.

4. Pure HPMC powder is fibrous under microscope or magnifying glass; Adulterated HPMC granular solids or crystals can be observed under a microscope or magnifying glass.

Common adulteration methods and identification methods:

1. Adding amide cellulose ether can make the solution viscosity of cellulose ether increase rapidly, resulting in the inability to use viscometer to identify.

Identification method: due to the characteristics of amide, this kind of cellulose ether solution will often appear drawing phenomenon, and good cellulose ether solution will not appear drawing phenomenon, the solution is like jelly, the so-called sticky and not connected.

2. Add cellulose ether to starch. Starch is generally insoluble in water, and solutions are often poorly transmittable.

Identification method: drop cellulose ether solution with iodine, the blue color can be considered as adding starch.

3. Add polyvinyl alcohol powder. As we all know, polyvinyl alcohol powder such as 2488, 1788 market price is often lower than cellulose ether, mixed with polyvinyl alcohol powder can reduce the cost of cellulose ether.

Identification method: this cellulose ether is often granular, larger density. Dissolve quickly with water, pick the solution with glass rod, there will be more obvious wire drawing phenomenon.

Conclusion:

Cellulose ether due to its special structure and group, its water retention is irreplaceable by other substances, whether mixed with what kind of filler, as long as it is a large amount of incorporation, its water retention will be greatly reduced. Normal 10W viscosity of HPMC in ordinary mortar mixing amount of 0.15~0.2‰, water retention rate > 88% is no problem, and inferior cellulose ether added to 0.3‰ of the water retention rate may not be able to reach 88%, mortar often bleeding more serious. Therefore, water retention rate is an important indicator of HPMC, is good or bad, as long as the mortar is added, it will be clear at a glance.