How to choose redispersible polymer powder?
There is no effective way other than to put the product into the experiment.
The selection of suitable redispersible latex powder should consider the following aspects:
1. The glass transition temperature of the redispersible polymer powder.
The glass transition temperature is that the polymer exhibits elasticity; below this temperature, the polymer exhibits brittleness. The glass transition temperature of general latex powder is -15±5℃, and the latex powder of regular manufacturers basically does not have this index. Problem. The glass transition temperature is a main indicator of the physical properties of the redispersible latex powder. For a specific product, a reasonable selection of the glass transition temperature of the redispersible latex powder is conducive to enhancing the flexibility of the product and avoiding problems such as cracking.
2. Minimum film forming temperature
After the redispersible latex powder is mixed with water and re-emulsified, it has similar properties to the original emulsion, that is, a film will be formed after the water evaporates. This film has high flexibility and good adhesion to various substrates. Different The minimum film-forming temperature of the latex powder produced by the manufacturer will be somewhat different. The index of some manufacturers is 0°C, and the index of some manufacturers is 5°C. As long as the film-forming temperature of latex powder with good quality is between 0 and 5°C between.
3. Redissolvability.
Inferior redispersible latex powder is partially or hardly soluble 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 is cured into one ton of rubber powder.
If 2% water content is counted, then 1.7 tons of emulsion is used to make one ton of rubber powder, plus 10% of ash content,
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 polymer powder, some customers simply dissolved the latex powder in water and stirred it by hand to test it, and found that there was no stickiness, thinking that it was not real latex powder.
In fact, the redispersible latex powder itself is not sticky, it is a powder formed after the polymer emulsion is spray-dried.
When the redispersible latex powder is mixed with water and re-emulsified, it has the same properties as the original emulsion, that is, the film formed after the water evaporates has high flexibility and has very good adhesion to various substrates.
It can also enhance the water retention of the material, prevent the cement mortar from hardening too quickly, dry and crack; increase the plasticity of the mortar and improve the construction workability. Dispersion, film-forming properties, flexibility (including pull-out test, whether the original strength is qualified) generally, the test results will be available after 10 days