Hydroxypropyl Methylcellulose (HPMC) is water soluble ethers with excellent performance, suitable for building coatings as retarders, water-retaining agents, thickeners and binders. 

Roles of Hydroxypropyl Methylcellulose (HPMC) in Building Materials

1. Water Retention—Improve Strength

Cement or gypsum-based product is able to gel only through the hydration reaction. Water makes silicates in cement into complex hydrates, anhydrous calcium sulfate and calcium sulfate hemihydrate in industrial gypsum into calcium sulfate dehydrate, so that these products could have certain strength. If there is no water, the reaction cannot occur, and there will be no strength. Especially if there is loss of water on the interface in contact with cement mortar, plaster and binders, there will be no strength and almost no bonding on this part. Generally speaking, the surfaces in contact with these materials are adsorbents, which more or less adsorb some water from the surface and result in incomplete hydration at this part, so that the bond strength or between plaster and wall will get decreased.

A major role of Hydroxypropyl Methylcellulose (HPMC) is to increase the water retention of building materials, greatly improve its bond strength and shear strength. The water retention of Hydroxypropyl Methylcellulose (HPMC) is getting better and better with the increase of viscosity.

2. Bonding strength

With the addition of Hydroxypropyl Methylcellulose (HPMC), the bonding of cement mortar, plaster and binders can be improved significantly, especially for the increase of initial bond force, which can ensure that pasting of ceramic tiles or tiles will not slide down and that the plaster and wall; brick and mortar are firmly bonded. The amount of Hydroxypropyl Methylcellulose (HPMC)  added should not be too much, on the one hand, will make the paste adherent to the construction tool, causing inconvenience for construction, and on the other hand will cause hollow defects on plaster and caulking materials.

3. Better Workability—Plasticity

With the addition of Hydroxypropyl Methylcellulose (HPMC), the workability of plaster has been significantly improved. The mortar without addition of Hydroxypropyl Methylcellulose (HPMC) is looser and easy to lose water, while after adding Hydroxypropyl Methylcellulose (HPMC), it seems to have “oiliness” and enables the wall joints full and surface smooth; the ceramic tiles or bricks tightly bonded with the base, and extend the opening time, suitable for large-scale construction.

4. Set-retarding effect

Hydroxypropyl Methylcelluloses (HPMC) can be used as set-retarders for cement-based building materials (such as mortar, plaster, binders, caulking materials, etc). If there is no need for particularly long construction time, such a retarding effect is sufficient to satisfy the use needs. Hydroxypropyl Methylcellulose (HPMC) also have certain set-retarding effects on gypsum-based products.

5. Air-entraining agent

After adding Hydroxypropyl Methylcellulose (HPMC), many tiny bubbles can be produced inside the material, like a honeycomb structure. Small bubbles act like “lubricants” and can have very good construction performance. Also, the honeycomb structure blocks the capillary action generated after original cement hardening and prevents the penetration of water, thus enabling the walls, tiles, cracks, etc. to have good waterproofing effects. The effect of the air-entraining agent also improves the frost and heat resistance of products, increases the heat and sound insulation effects, and meanwhile reduces the bulk density of product.

Shandong Kundu Chemical Co., Ltd. is a professional manufacturer and exporter of Hydroxypropyl Methylcelluloses (HPMC). If you have any questions about HPMC, feel free to contact us.