Do You Know The HPMC Grade And Solubility?
Aug. 14, 2021
Hydroxypropyl methyl cellulose (HPMC) is made from high purity cotton cellulose by special etherification under alkaline conditions. In recent years, HPMC, as a functional admixture, mainly plays the role of water retention and thickening in the construction industry and is widely used in tile adhesives. Tile adhesive is a modern new decorative material used to paste tiles, face tiles, floor tiles and other decorative materials. It has the advantages of high adhesion and good flexibility. In this article, hpmc manufacturer tells you what to consider before you buy.
HPMC is divided into construction grade HPMC, daily chemical grade HPMC, food grade HPMC, pharmaceutical grade HPMC according to application fields. Tile adhesive uses HPMC, which belongs to building material grade.
In terms of viscosity, viscosity is an essential index of HPMC. the higher the viscosity of HPMC solution, the better the viscosity of the tile adhesive and the better the adhesion to the substrate. The stronger the resistance to sagging and dispersion, but its viscosity is too large, which will affect the fluidity and workability of the tile adhesive.
According to the solubility of HPMC in water, HPMC can be divided into delayed-dissolution HPMC, and non-delayed-dissolution HPMC. in the construction industry, HPMC is often put into neutral water and the HPMC product is dissolved separately to determine whether the HPMC has been surface treated. Products that clump quickly and do not disperse after being placed in neutral water alone are non-surface treated products; products that can be dispersed without clumping after surface treatment after being placed in neutral water independently.
Non-surface treated HPMC
When the surface untreated HPMC product is dissolved alone, its particles dissolve quickly and form a film quickly so that water no longer enters other particles, causing clumping and agglomeration.
In practice, the series products dissolve extremely fast after physical dispersion with solid particles such as glue powder, cement and sand, without agglomeration and caking. Therefore, HPMC without surface treatment can be used for cement-based and gypsum-grade tile adhesives, but not for paste emulsion-based tile adhesives.
Surface treated HPMC
Surface treated HPMC product particles, in neutral water, individual particles can be dispersed without agglomeration, but will not become sticky immediately. After soaking for a certain time, the water can dissolve the HPMC particles after the chemical structure of the surface treatment is destroyed.
In actual production operation, the series products tend to dissolve after being dispersed with other solid granular materials under alkaline conditions. Its dissolution speed is no different from the untreated product. In the construction process, cement tile adhesive and gypsum-based tile adhesive are alkaline systems, and the addition of HPMC is very small. It can be evenly dispersed between these particles. When water is added, HPMC dissolves quickly.
Solutions for different scenarios
Especially in kitchen and bathroom, it is usually easy to mold and breed bacteria, so it is recommended to use HPMC with high viscosity and water resistance. high viscosity and waterproof HPMC will make sealant and tile adhesive with good sealing performance, prevent various problems caused by moisture, prolong the life of decoration and reduce later maintenance.
Such as swimming pools and outdoor balconies, exterior tile adhesives need to have waterproof, heat-resistant, cold-resistant and wear-resistant properties. Since outdoor spaces are generally exposed to sun and rain, pool water and mud for a long time, strong adhesives must be used to solve these problems. Therefore, HPMC with high viscosity must be selected to make tile adhesives meet these needs.