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Interpretation of HPMC Problems of Hydroxypropyl Methyl Cellulose (Part 1)

Nov. 05, 2020

1, Hydroxypropyl methyl cellulose HPMC is divided into several kinds, what is the difference between its use?

A: Construction Grade HPMC can be divided into quick-dissolving type and hot-dissolving type. Quick-dissolving type products disperse quickly in cold water and disappear in water. At this time, the liquid has no viscosity, because HPMC is only dispersed in water and does not really dissolve.After about 2 minutes, the viscosity of the liquid gradually increases to form a clear, viscous gel.Hot dissolve product, in cold water, can be in hot water, quickly disperse, disappear in hot water, when the temperature drops to a certain temperature, viscosity slowly appear, until the formation of a transparent viscous gel.The hot dissolve type can only be used in putty powder and mortar, in liquid glue and paint, there will be clumping phenomenon, can not be used.Instant type, a wide range of applications, in putty powder and mortar, as well as liquid glue and paint, can be used, there is no taboo.

2, hydroxypropyl methyl cellulose HPMC) what is the main use?

A :HPMC is widely used in construction materials, coatings, synthetic resins, ceramics, medicine, food, textile, agriculture, cosmetics, tobacco and other industries.According to the use of HPMC can be divided into: construction grade, food grade and medical grade.At present domestic is mostly building grade, in building grade, the dosage of putty powder is very big, about 90% is used to make putty powder, the rest is used for cement mortar and glue.

3, Hydroxypropyl methyl cellulose HPMC dissolution methods have those?

A: Hot-water solution: As Hydroxypropyl Methyl Cellulose does not dissolve in hot water, at the initial stage, HPMC can be dispersed uniformly in hot water and then dissolved rapidly when cooled. Two typical methods are described as follows:

1) Add 1/3 or 2/3 of the required water into the container and heat it to 70℃. Disperse HPMC to prepare hot water slurry according to 1) method;Then add the remaining amount of cold water to the hot water slurry and stir to cool the mixture.

Powder mixing method: Mix HPMC powder with a large number of other powder ingredients, fully mix with a blender, and then add water to dissolve, then HPMC can be dissolved, but not agglomerate, because every tiny corner, only a little HPMC powder, will immediately dissolve in water.-- This is the method used by putty powder and mortar manufacturers.Hydroxypropyl methyl cellulose (HPMC) is used as thickener and water-retaining agent in putty mortar.

2) Put the required amount of hot water into the container and heat it to about 70℃.In the slow stirring gradually add hydroxypropyl methyl cellulose, HPMC began to float on the surface of the water, and then gradually form a slurry, under the stirring cooling slurry.

Construction Grade HPMC

Construction Grade HPMC

4. How to simply and intuitively determine the quality of hydroxypropyl methyl cellulose (HPMC)?

Answer :(1) specific gravity: specific gravity is bigger, heavier want to be better.

(2) Whiteness: Whiteness does not determine whether HPMC is easy to use, and if whitening agent is added in the production process, its quality will be affected.However, good products are mostly whiter.

(3) Fineness: The fineness of HPMC is generally 80 mesh and 100 mesh, with less 120 purposes. Most HPMC produced in Hebei is 80 mesh. The finer the fineness is, the better it is in general.

(4) Transmittance: Put HPMC for putty powder into water to form a transparent gel and observe its transmittance. The greater the transmittance, the better, indicating less insoluble matter.The transmittance of the vertical reactor is generally good, while that of the horizontal reactor is worse, but it does not mean that the quality produced by the vertical reactor is better than that produced by the horizontal reactor. There are many factors that determine the quality of the product.The content of hydroxypropyl inside is high, the content of hydroxypropyl is high, it is better to keep water.

 


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