Hydroxypropyl Methyl Cellulose (HPMC)
1. It is stable to acid and alkali, and its aqueous solution is very stable in the range of pH=2-12. Caustic soda and lime water do not have much effect on its performance, but alkali can speed up its dissolution rate and slightly increase its viscosity.
2. HPMC is a high-efficiency water-retaining agent for dry powder mortar system, which can reduce the bleeding rate and layering degree of mortar, improve the cohesion of mortar, effectively inhibit the formation of plastic cracks in mortar, and reduce the plastic cracking index of mortar.
3. It is a non-ionic and non-polymeric electrolyte, which is very stable in aqueous solutions containing metal salts and organic electrolytes, and can be added to building materials for a long time to ensure its durability is improved.
4. The working performance of the mortar has been significantly improved. The mortar seems to be “oily”, which can make the wall joints full, smooth the surface, make the mortar and the base layer bond firmly, and prolong the operation time.
water retention
Achieve internal maintenance, which is conducive to the improvement of long-term strength
Inhibit bleeding, prevent mortar from settling and shrinking
Improve the crack resistance of mortar.
thicken
Anti-segregation, improve mortar uniformity
Improves wet bond strength and improves sag resistance.
bleed air
Improve mortar performance
As the viscosity of cellulose becomes higher and the molecular chain is longer, the air-entraining effect is more obvious
Retarding
Synergizes with water retention to prolong the open time of the mortar.
Hydroxypropyl starch ether (HPS)
1. The higher hydroxypropyl content in starch ether endows the system with stable hydrophilicity, making free water into bound water and playing a good role in water retention.
2. Starch ethers with different hydroxypropyl content differ in their ability to assist cellulose in water retention under the same dosage.
3. The substitution of hydroxypropyl group increases the expansion degree in water and compresses the flow space of the particles, thereby increasing the viscosity and thickening effect.
Thixotropic lubricity
The rapid dispersion of starch ether in the mortar system changes the rheology of the mortar and endows it with thixotropy. When an external force is applied, the viscosity of the mortar will decrease, ensuring good workability, pumpability, and endowment When the external force is withdrawn, the viscosity increases, so that the mortar has good anti-sagging and anti-sag performance, and in the putty powder, it has the advantages of improving the brightness of the putty oil, polishing brightness, etc.
The effect of auxiliary water retention
Due to the effect of the hydroxypropyl group in the system, starch ether itself has hydrophilic characteristics. When it is combined with cellulose or added to a certain amount of mortar, it can increase water retention to a certain extent and improve surface drying time.
Anti-sag and anti-slip
Excellent anti-sagging effect, shaping effect
Redispersible latex powder
1. Improve the workability of mortar
The rubber powder particles are dispersed in the system, endowing the system with good fluidity, improving the workability and workability of the mortar.
2. Improve the bond strength and cohesion of mortar
After the rubber powder is dispersed into a film, the inorganic matter and organic matter in the mortar system are fused together. It can be imagined that the cement sand in the mortar is the skeleton, and the latex powder forms the ligament in it, which increases the cohesion and strength. form a flexible structure.
3. Improve the weather resistance and freeze-thaw resistance of mortar
Latex powder is a thermoplastic resin with good flexibility, which can make the mortar cope with external cold and heat changes, and effectively prevent the mortar from cracking due to temperature changes.
4. Improve the flexural strength of mortar
The advantages of polymer and cement paste complement each other. When cracks are generated by external force, the polymer can cross the cracks and inhibit the cracks from expanding, so that the fracture toughness and deformability of the mortar are improved.
Post time: Apr-19-2023