1、Hydroxypropyl methyl cellulose (HPMC) viscosity how much is appropriate?
Putty powder is generally 100,000 can be, mortar in the higher requirements, to 150,000 to work well. Moreover, the most important role of HPMC is water retention, followed by thickening. In 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 is better, when the viscosity is more than 100,000, the viscosity of the water retention of the impact is not great.
2, From what aspects of the simple judgment of the quality of hydroxypropyl methyl cellulose (HPMC)?
(1) Whiteness: Although whiteness cannot decide whether HPMC is good or not, and if it is added whitening agent in the production process, it will affect its quality. However, most of the good products have good whiteness.
(2) Fineness: The fineness of HPMC generally has 80 mesh and 100 mesh, 120 mesh is less, the finer the fineness, the better in general.
(3) Transmittance: Put hydroxypropyl methyl cellulose (HPMC) into water, form transparent colloid, look at its transmittance, the greater the transmittance, the better, that is, the insoluble matter inside less. Vertical reactor through the degree of generally good, horizontal reactor to be worse, but can not indicate that the quality of vertical kettle production than the production of horizontal kettle, product quality and 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.
3、HPMC in the application of putty powder, what is the main role?
HPMC in the putty powder, thickening, water retention and construction of three roles.
(1) thickening: cellulose can be thickened to play the role of suspension, so that the solution to maintain a uniform up and down the same role, anti-flow hanging.
(2) Water retention: make putty powder dry slower, to assist the reaction of gray calcium under the action of water.
(3) Construction: cellulose has a lubricating effect, can make putty powder has good constructibility. hpmc does not participate in any chemical reaction, only play a supporting role.
4、The relationship between the viscosity of HPMC and temperature, what should be noted in the actual application?
The viscosity of HPMC is inversely proportional to the temperature, that is to say, the viscosity increases with the decrease of temperature. When we say the viscosity of a certain product, it means the result of its 2% aqueous solution tested at a temperature of 20 degrees Celsius.
In practical application, in areas where there is a big temperature difference between summer and winter, attention should be paid to the fact that it is recommended to use a relatively lower viscosity in winter, which is more favorable for construction. Otherwise, when the temperature is low, the viscosity of cellulose will increase, and the feel will be heavy when scraping.
Medium viscosity: 75000-100000 mainly used for putty
Reason: good water retention
High viscosity: 150000-200000 is mainly used for polystyrene granule thermal insulation mortar adhesive powder material and glass beads thermal insulation mortar.
Reason: high viscosity, mortar is not easy to fall off, hanging, improve the construction.
If you want to know more about HPMC please feel free to contact us!
