Hydroxypropyl methylcellulose is a non-ionic cellulose ether, the appearance is white powder, odorless and tasteless. Soluble in water, most polar organic solvents and appropriate proportions of ethanol/water, propanol/water and dichloroethane, but insoluble in ether, acetone and absolute ethanol. It will swell into a clear or slightly cloudy colloidal solution in cold water.
Its aqueous solution has surface activity, high transparency and stable properties. Hydroxypropyl methylcellulose has thermal gelation characteristics, so the aqueous solution will precipitate to form a gel after heating, and will dissolve after cooling. Products of different specifications have different gelling temperatures. Its solubility varies with viscosity, the lower the viscosity, the greater the solubility. Different specifications of hydroxypropyl methylcellulose have certain differences in performance. The dissolution of hydroxypropyl methylcellulose in water is not affected by pH.
Hydroxypropyl methylcellulose has the characteristics of thickening power, salt discharge performance, pH stability, water retention, excellent film-forming property, wide range of enzyme resistance, dispersibility and adhesion.
In latex paints and water-soluble resin coatings, hydroxypropyl methylcellulose is used as a film-forming agent, thickener, emulsifier and stabilizer to make the coating film have good abrasion resistance, leveling and adhesion, and improve Surface tension, pH stability and compatibility with metallic materials. In water-based paints, hydroxypropyl methylcellulose has excellent storage stability, maintains uniform viscosity, makes pigments dispersed evenly, and is basically not affected by pH.
In putty, the main functions of cellulose are water retention, adhesion, lubrication and so on. Hydroxypropyl methylcellulose has high water retention properties, surface optics and improved uniformity. This helps to avoid skinning and powdering, improves resistance to shrinkage, cracking and vertical flow, and increases work efficiency as the application process is comfortable and labor-saving.
In the production of synthetic resin, hydroxypropyl methylcellulose acts as a protective colloid agent, which can effectively prevent the agglomeration of polymer particles. In vinyl chloride (VC) float polymerization, the quality of the dispersion system directly affects the product, PVC resin, processing quality and product quality. It helps to improve the thermal stability of the resin and control the particle size distribution (that is, adjust the density of PVC). The PVC resin made of high-quality cellulose ether can not only ensure that the performance meets international standards, but also has apparent physical properties, fine particle characteristics and excellent melt rheological properties.
In the bonding mortar, surface mortar and other materials in the thermal insulation mortar system, cellulose mainly plays the role of bonding, water retention and increasing strength. It also helps improve workability, water retention and hang resistance. In addition, it has increased resistance to vertical flow, shrinkage and cracking, resulting in improved bond strength and work efficiency.
In the interface agent, hydroxypropyl methylcellulose mainly acts as a thickener, which can improve the tensile strength and bending strength. It also helps to improve surface coating, enhance adhesion and increase the bond strength of the mortar. In addition, good permeability can improve the uniformity of the interface, enhance the lubricity and fluidity of the mortar, make it easier to paint, and thus improve work efficiency.