Answers to some questions on hydroxypropylmethylcellulose (I)

1、Hydroxypropyl methyl cellulose (HPMC) What is the main use?

--A: HPMC is widely used in building materials, coatings, synthetic resins, ceramics, pharmaceuticals, food, textiles, agriculture, cosmetics, tobacco and other industries.HPMC can be divided into: construction grade, food grade and pharmaceutical grade. At present, most of the domestically produced ones are construction grade. In the construction grade, putty powder has a large amount, about 90% of it is used to make putty powder, and the rest is used to make cement mortar and glue.

2、Hydroxypropyl methyl cellulose (HPMC) is divided into several kinds, what is the difference between their uses?

--A: HPMC can be divided into instant and hot soluble type, instant product, meet the cold water quickly dispersed, disappeared inside the water, at this time there is no viscosity of the liquid, because HPMC is just dispersed in the water, there is no real dissolution. About 2 minutes, the viscosity of the liquid slowly becomes larger, forming a transparent viscous gel. Hot soluble products, cold water clumping, can be in hot water, quickly dispersed, disappeared in hot water, to be the temperature down to a certain temperature (our products for 65 degrees Celsius), the viscosity slowly appeared, until the formation of transparent viscous colloid. Hot soluble type can only be used in putty powder and mortar, in the liquid glue and paint, there will be clumping phenomenon, can not be used. Instant type, application range is wider, in putty powder and mortar, as well as liquid glue and paint, can be used, there is no contraindication.

3、Hydroxypropyl methyl cellulose (HPMC) dissolution methods are those?

--A: Hot water dissolution method: Since HPMC does not dissolve in hot water, initially HPMC can be evenly dispersed in hot water, and then quickly dissolved when cooled, two typical methods are described as follows:

1), Put the required amount of hot water in a container and heat it to about 70°C. Gradually add hydroxypropyl methylcellulose under slow stirring, at first the HPMC floats on the surface of the water, and then gradually a slurry is formed, and the slurry is cooled under stirring.

2), add 1/3 or 2/3 of the required amount of water in a container and heat it to 70°C, and prepare a hot water slurry by dispersing HPMC according to the method of 1); then add the remaining amount of cold water to the hot water slurry and cool the mixture after stirring.

Powder mixing method: HPMC powder and a large number of other powdery substances ingredients, with a mixer to fully mix, and then add water to dissolve, then HPMC can be dissolved at this time, without clumping and cohesion, because each tiny little corner, only a little bit of HPMC powder, water will dissolve immediately. --Putty powder and mortar manufacturers use this method. [Hydroxypropyl methyl cellulose (HPMC) is used as a thickener and water retention agent in putty powder mortar].

4、How to judge the quality of Hydroxypropyl Methyl Cellulose (HPMC) in a simple and intuitive way?

--Answer: (1) Whiteness: although the whiteness can not decide whether HPMC is good or not, and if the whitening agent is added in the production process, it will affect its quality. However, most of the good products have good whiteness. (2) fineness: HPMC fineness generally have 80 mesh and 100 mesh, 120 mesh less, Hebei produced HPMC mostly 80 mesh, the finer the finer, generally speaking, the better. (3) Transmittance: put hydroxypropyl methyl cellulose (HPMC) into the water, after the formation of transparent colloid, look at its transmittance, transmittance, the greater the better, that is, inside the insoluble matter less. Vertical reactor through the degree of generally good, horizontal reactor to be worse, but does not indicate that the quality of vertical kettle production than the production of horizontal kettle is good, product quality there are many factors to decide. (4) Specific gravity: the larger the specific gravity, the heavier the better. Specific gravity, generally because of the high content of hydroxypropyl, hydroxypropyl content is high, the water retention to be better.

5, hydroxypropyl methyl cellulose (HPMC) viscosity how much is appropriate?

--A: Putty powder generally 100,000 can be, mortar requirements of higher, to 150,000 to be used. Moreover, the more important role of HPMC is water retention, followed by thickening. In the putty powder, as long as the water retention is good, the viscosity is lower (7-8 million), it is also possible, of course, the viscosity is larger, the relative water retention to be better, when the viscosity is more than 100,000, the viscosity of the water retention of the impact is not great.

6, hydroxypropyl methyl cellulose (HPMC) what are the main technical indicators?

--A: hydroxypropyl content and viscosity, most users are concerned about these two indicators. High hydroxypropyl content, water retention is generally better. Viscosity, water retention, relative (rather than absolute) is also better, and viscosity, in the cement mortar is better.

7, hydroxypropyl methyl cellulose (HPMC) what are the main raw materials?

-- A: hydroxypropyl methyl cellulose (HPMC) of the main raw materials: refined cotton, chloromethane, propylene oxide, and other raw materials, soda ash, acid, toluene, isopropyl alcohol and so on.