Introduction of Hydroxypropyl Methyl Cellulose (HPMC)
The smell of hydroxypropyl methylcellulose (HPMC)
The HPMC produced by the solvent method uses toluene and isopropyl alcohol as a solvent. If the washing is not very good, there will be some residual taste.
How to choose the right hydroxypropyl methylcellulose (HPMC)
Application of putty powder: lower requirements, viscosity of 100,000. it is ok, it is important to keep water. Application of mortar: high requirements, high viscosity, 150,000 is better. Glue application: Need instant type product, high viscosity.
What should be noted about the relationship between viscosity and temperature of HPMC?
The viscosity of HPMC is inversely proportional to temperature. That is, the viscosity increases with decreasing temperature. The viscosity of a product we usually refer to is the result of a 2% aqueous solution at a temperature of 20 degrees Celsius.
In practical applications, in areas with large temperature differences between summer and winter. it should be noted that it is recommended to use a relatively low viscosity during the winter, which is more conducive to construction. Otherwise, when the temperature is low, the viscosity of cellulose will increase. And when it is scraped, the hand feel will be heavy.
Medium viscosity: 75000-100000 Mainly used for putty
Reason: good water retention
High viscosity: 150000-200000 Mainly used for polystyrene granule insulation mortar powder and vitrified microbead insulation mortar.
Reason: The viscosity is high, the mortar is not easy to fall, sag, and the construction is improve.
However, in general, the higher the viscosity, the better the water retention.so many dry mortar plants consider the cost.And replace the medium and low viscosity cellulose (20000-40000) with medium viscosity cellulose (75000-100000) to reduce the amount of addition. .
The difference between cold water soluble type and hot soluble type of hydroxypropyl methyl cellulose
HPMC’s cold water instant type is surface treat with glyoxal and quickly disperse in cold water, but it is not really dissolve. When the viscosity comes up, it dissolves.
The hot soluble form is not surface treat with glyoxal. When the amount of glyoxal is large, the dispersion is fast, but the viscosity is slow, and the amount is small.
Relationship between gel temperature of hydroxypropyl methylcellulose
The gel temperature of HPMC is related to its methoxy content.so the lower the methoxy content, the higher the gel temperature.
The relationship between the powder of putty powder and HPMC
The powder of putty powder is mainly related to the quality of gray calcium.And has little to do with HPMC. The low calcium content of gray calcium and the inappropriate ratio of CaO and Ca(OH)2 in gray calcium can cause powder loss. If it is related to HPMC, then if the water retention of HPMC is poor, it will also cause powder loss.
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