Hydroxypropyl methyl cellulose HPMC is a natural polymer material cellulose as raw material, through a series of chemical processing and made of non-ionic cellulose ether. They are an odorless, tasteless, non-toxic white powder that expands into a clear or slightly cloudy colloid solution in cold water. With thickening, adhesion, dispersion, emulsification, film formation, suspension, adsorption, gel, surface activity, moisture retention and colloidal protection, etc. Hydroxypropyl methyl cellulose HPMC, methyl cellulose MC can be used in building materials, coating industry, synthetic resin, ceramic industry, medicine, food, textile, agriculture, daily chemicals and other industries.
Chemical equation:
[C6H7O2(OH) 3-M-N (OCH3) M (OCH2CH(OH)CH3) N] X
Properties of HPMC used in Construction
1. Water retention
Hydroxypropyl methyl cellulose HPMC for construction prevents excessive absorption of water by the substrate, and water should be retained in the plaster as much as possible during the completion of gypsum solidification. This property is known as water retention, and is proportional to the viscosity of the building specific hydroxypropyl methyl cellulose HPMC solution in the stucco, the higher the viscosity of the solution, the higher the water retention capacity.
As soon as the water content is increased, the water retention capacity is decreased, because the increased water diluted the construction of hydroxypropyl methyl cellulose HPMC solution, resulting in a decrease in viscosity.
2. Sag resistance
A stucco that is resistant to flow and hanging allows the builder to apply a thick coating without vertical flow, which also means that the stucco itself is thixotropic, otherwise it slides downward during construction.
3. Reduce viscosity, easy construction
By adding a variety of building special hydroxypropyl methyl cellulose HPMC products, low viscosity and easy construction can be obtained from the gypsum plaster, using low viscosity level building dedicated hydroxypropyl methyl cellulose HPMC, relatively less viscosity and easy construction, however, low viscosity building dedicated hydroxypropyl methyl cellulose HPMC water retention ability is weak, needs to raise added amount.
4. Capacity growth rate of stucco
For a fixed amount of dry mortar, it is more economical to produce a higher wet mortar volume, which can be achieved by adding more water and bubbles. But too much water and bubbles can damage the strength.
HPMC application in construction materials:
1.Ceramic tile adhesive
(1)It is easy to dry mixing ingredients, will not produce clumps, improve the speed of application, improve the construction performance, save working time, reduce the cost of work.
(2) By prolonging the opening time, improve tile efficiency, and provide excellent adhesion effect.
2. Cement based plaster
(1) Improve the uniformity, make the mortar more easy to trowel coating, at the same time improve the anti-hanging, enhance the fluidity and pumping, improve the work efficiency.
(2)The high water retention, prolong the placement time of mortar, improve the work efficiency, conducive to the hydration and solidification of mortar to produce high mechanical strength.
(3) Control the introduction of air, so as to eliminate cracks on the surface of the coating, forming an ideal smooth surface.
3. Gypsum base plaster and gypsum render products
(1) Improve the uniformity, make the mortar more easy to trowel coating, at the same time improve the anti-hanging, enhance the fluidity and pumping, improve the work efficiency.
(2)The high water retention, prolong the placement time of mortar, improve the work efficiency, conducive to the hydration and solidification of mortar to produce high mechanical strength.
(3)Control the consistency of mortar uniformity, the formation of an ideal surface coating.
4. Masonry mortar
(1) Enhance the viscosity of masonry surface, enhance water retention, improve the strength of mortar.
(2) Improve lubricity and plasticity, improve construction; The mortar improved by cellulose ether is easier to construct, saves construction time and reduces construction cost.
(3)cellulose ether, especially high water retention, is suitable for high water absorption brick.
5. Plate joint filler
(1) Excellent water retention, prolong opening time, improve work efficiency. High lubricant, easier to mix.
(2)The anti-shrinkage and anti-cracking properties were improved and the surface quality of the coating was improved.
(3) Improve the adhesion of the bonded surface, providing a smooth, smooth texture.
6.Self leveling ground materials
(1)provide viscosity, can be used as anti-settlement AIDS.
(2)Enhance the pumping of liquidity, improve the efficiency of paving the ground.
(3) Control water retention and shrinkage, reduce the cracking and contraction of the ground.
7.Water based paint and coatings
(1)Prevent solid precipitation, prolong the container period of the product.
(2)High biological stability and excellent compatibility with other components.
(3)Improve fluidity, provide good anti-splash, anti-drop and flow resistance, ensure excellent surface finish.
8.Wallpaper powder
(1)quick to dissolve without lumps, which is good for mixing.
(2)provides high bond strength.
9.Extrusion molding cement plate
(1)has high cohesiveness and lubricity, enhance the processing performance of extrusion products.
(2) Improve green strength, promote hydration curing effect, increase the yield of finished product.
10.premixed mortar
in premixed mortar water retention is better than ordinary products, to ensure full hydration of inorganic cementitious materials, significantly prevent drying too fast caused by reduced bond strength, and drying shrinkage caused by cracking. HPMC also has a certain air entraining effect, premixed mortar special HPMC products, air entraining right amount, uniform and small bubbles, can improve the strength and gloss of premixed mortar. Premixed mortar special HPMC products have a certain slowing effect, can prolong the opening time of premixed mortar, reduce the difficulty of construction.