Introduction of Hydroxypropyl Methyl Cellulose (HPMC)(2)

Method for dissolving hydroxypropyl methylcellulose (HPMC)

Hot water dissolution method: Since HPMC is not dissolve in hot water, the initial HPMC can be uniformly dispersed in hot water. It then dissolves rapidly upon cooling. Two typical methods are describe below:

1) Place the required amount of hot water in the container and heat to about 70 °C. Hydroxypropyl methylcellulose was gradually add with slow stirring to start the HPMC floating on the surface of the water. A slurry is gradually form and the slurry is cool with stirring.

2) Add the required amount of 1/3 or 2/3 of water to the vessel and heat to 70 °C. The HPMC was dispersed according to the method of 1) to prepare a hot water slurry; then the remaining amount of cold water was add to the hot water slurry, and the mixture was cooled after stirring.

Powder mixing method: The HPMC powder is mix with a large amount of other powdery substances and thoroughly mix with a mixer. After adding water to dissolve, then HPMC can be dissolved without clumping.

Because every little small corner, only a little HPMC powder will dissolve immediately when it meets water. – This method is use by putty powder and mortar manufacturers. [Hydroxypropyl methylcellulose (HPMC) is used as a thickener and water retention agent in putty mortar. ]

The amount of hydroxypropyl methylcellulose (HPMC) in putty powder

The amount of HPMC used in practical applications varies depending on the climate, temperature, local ash calcium quality, formula of putty powder, and “quality required by customers.” In general terms, between 4 kg and 5 kg.

Main technical indicators of hydroxypropyl methylcellulose (HPMC)

The hydroxypropyl content and viscosity, which most users care about are these two indicators. If the hydroxypropyl content is high, the water retention is generally better. Viscosity, water retention, relative (rather than absolute), and high viscosity, better in cement mortar.

The main raw material of hydroxypropyl methylcellulose (HPMC)

The main raw materials of hydroxypropyl methylcellulose (HPMC): refined cotton, methyl chloride, propylene oxide, other raw materials, such as caustic soda, acid, toluene, isopropanol and the like.

Application of HPMC in putty powder

In the putty powder, HPMC plays the role of thickening, water retention and construction.
Thickening: Cellulose can be thicken to suspend, keep the solution uniform and uniform, and resistant to sagging.
Water retention: The putty powder is dried slowly, and the auxiliary ash calcium reacts under the action of water.
Construction: Cellulose has a lubricating effect, which can make the putty powder have good workability.

HPMC does not participate in any chemical reactions and only plays a supporting role. Putty powder with water, on the wall, is a chemical reaction. Because of the formation of new substances, the putty powder on the wall is remove from the wall, ground into powder, and reuse, it will not work. Because new substances have been form (calcium carbonate ).

The main components of ash calcium powder are: Ca(OH)2, a mixture of CaO and a small amount of CaCO3, CaO+H2O=Ca(OH)2-Ca(OH)2+CO2=CaCO3↓+H2O ash calcium in water and air Under the action of CO2, calcium carbonate is form. While HPMC only retains water, it assists the better reaction of ash calcium, and it does not participate in any reaction itself.

Application of HPMC in putty powder, cause of foam in putty powder

In the putty powder, HPMC plays the role of thickening, water retention and construction. Do not participate in any reaction. The reason for the bubble: 1, the water is too much. 2, the bottom layer is not dry, just scrape a layer on the top, it is also easy to foam.

If you have any questions, you can send them to my email : tanyatao@qinahaochem.com

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