Water retention principle of cellulose in putty and mortar
April 22nd 2024
The ash content from the regular redispersible polymer powder factory is generally 10±2
The ash content standard is within 12%, and the quality and price are comparable
Some domestic latex powders are more than 30%, and even some rubber powders have as much as 50% ash.
Now the quality and price of dispersible polymer powder on the market are uneven, try to choose
Low ash content, high cost performance and relatively stable quality of supply.
How to choose redispersible latex powder, generally it is really impossible to start when making the formula,
There is no effective way other than putting it into the product for experimentation.
The selection of suitable dispersible polymer powder should be considered from the following aspects:
1. The glass transition temperature of the dispersible polymer powder.
The glass transition temperature is the polymer that exhibits elasticity; below this temperature, the polymer exhibits brittleness.
Generally, the glass transition temperature of latex powder is -15±5℃.
Basically no problem.
The glass transition temperature is a major indicator of the physical properties of dispersible polymer powders, and for specific products,
Reasonable selection of the glass transition temperature of redispersible polymer powder is conducive to enhancing product flexibility and avoiding
cracking, etc.
2. Minimum film forming temperature
After the redispersible and redispersible polymer powder is mixed with water and re-emulsified, it has similar properties to the original emulsion.
That is, after the water evaporates, a film will be formed, which has high flexibility and good adhesion to various substrates.
The minimum film-forming temperature of latex powder produced by different manufacturers will be somewhat different.
The index of some manufacturers is 5 ℃, as long as the latex powder with good quality has a film-forming temperature between 0 and 5 ℃.
3. Redissolvable properties.
Inferior dispersible polymer powders are partially or hardly dissolved in cold water or alkaline water.
4. Price.
The solid content of the emulsion is about 53%, which means that about 1.9 tons of emulsion solidify into one ton of rubber powder.
If you count 2% water content, that is 1.7 tons of emulsion to make one ton of rubber powder, plus 10% of ash,
It takes about 1.5 tons of emulsion to produce one ton of rubber powder. 5. Aqueous solution of latex powder
In order to test the viscosity of the redispersible latex powder, some customers simply dissolve the latex powder in
After stirring in water, I tested it by hand, and found that it was not sticky, so I thought it was not real latex powder.
In fact, redispersible latex powder itself is not sticky, it is formed by spray drying of polymer emulsion of powder.
When the redispersible polymer powder is mixed with water and re-emulsified, it has the same properties as the original emulsion, that is, moisture
The films formed after evaporation are highly flexible and adhere very well to various substrates.
It can also enhance the water retention of the material and prevent the cement mortar from hardening, drying and cracking too quickly;
Increase the plasticity of the mortar and improve the construction workability. If an experiment is to be done, it must be proportional
Do the mortar retest to see its dispersibility, film formation, flexibility (including pull-out test,
Whether the original strength is qualified) In general, the experimental results can be obtained after 10 days
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