Application and Property of HPMC

Views: 176 Author: Site Editor Publish Time: 2022-01-26 Origin: Site

Hydroxypropyl methyl Cellulose (HPMC) , is non-ionic cellulose ether, and modified cellulose ether derivatives polymer that is off-white in color and considered safe for human consumption. It is odorless, tasteless, and in the shape of white powder. Hydroxypropyl Methyl Cellulose is made by mature high polymer cellulose as raw material and a series of chemical processing. It is used in various applications in construction, food, pharmaceutical, and personal care industries. It functions as a thickener, binder, film former, water retention agent, suspension aid, and a lubricant depending on the application.

HPMC, Hypromellose is a thickener for aqueous and non-aqueous systems, clear films with grease resistance, binders, lubricants, steric stabilizer and water retention aid. Dissolves in water, undergoes reversible gelation upon heating, non-ionic. According to their molecular weight or degree of substitution, it can form colloidal solution in water, it can not be soluble in solvent, the colloidal solution has the characteristics of high viscosity, adhesion, thickening, emulsifying, shaped, good water retention, protective colloid, film forming, acid resistance, salt tolerance, suspension and other characteristics, and the physiological harm. so it has been widely used in dry mix mortars, it is the most important additive for wall putty, tile adhesive, all kinds of gypsum and cement based dry mix mortars, it is also widely used in pharmaceutical as film forming, released control agent, it can be used for food thickening, emulsification, anti sedimentation.etc. Hydroxypropyl methyl cellulose (HPMC) can dissolve in both cold and hot water, add the appropriate water in a container, heated to 70 degrees Celsius, then keep stirring, adding hydroxypropyl methyl cellulose, it will form a slurry after cooling. This is the main solution of hydroxypropyl methyl cellulose, it is used in many different applications.

 HPMC

Application of HPMC

1.In Construction:

In dry mix mortars,  the dosage is very low (usually 0.2-0.7%) and it mix with cement/gypsum/sand etc. thoroughly, it can be soluble easily and no need to use hot water to disperse.As the water-retaining agent and retarder of cement mortar, it enables the mortar to have pumping property. In plaster slurry, gypsum materials, putty powder or other building materials, it acts as a binder and helps to improve the spreadability and prolong the operating time.Hydroxypropyl Methylcellulose has high water-holding capacity, can extend the working time of mortar, improve work efficiency and is good for the mortar to produce high mechanical strength during solidification.

2. In PVC industry:

In the production of PVC, it can act as a dispersing agent, the main additive in the preparation of PVC by suspension polymerization.In the polymerization process of PVC suspension polymerization system, The use of Hydroxypropyl Methylcellulose as a dispersant can improve suspension dispersion properties, can also improve the particle morphology, and enhance the absorption performance on plasticizers.

3. In Pharmaceutical, Food Personal care :

HPMC is non-ionic, and in the preparation process can be effectively purified by washing with hot water, it has a very low ash content. Hydroxypropyl Methylcellulose products can fully meet the standards for use of pharma, food, and personal care products.

 

Property of HPMC 

Hydroxypropyl MethylCellulose is soluble in water, most polar organic solvents, and the appropriate proportion of ethanol/water, propanol /water and dichloroethane, but insoluble in diethyl ether, acetone, and anhydrous alcohol. In cold water, it will swell into a clear or slightly turbid colloidal solution.Its aqueous solution has surface activity, high transparency and stable properties. Hydroxypropyl MethylCellulose has thermal gelation properties, so after heating the aqueous solution will precipitate and form gels, and dissolve again after cooling. Products of different specifications have different gelling temperatures. Its solubility varies with the viscosity, and the lower the viscosity is, the greater the solubility will be. There are some differences in the properties of Hydroxypropyl MethylCellulose of different specifications. The dissolution of Hydroxypropyl MethylCellulose in water is not affected by the pH value.

1. Water retention Property: In wall putty/Skimcoat, the main roles of cellulose ether are water retention, adhesion, lubrication and so on. Hydroxypropyl MethylCellulose has high water-holding performance, surface opticity and improves uniformity. This helps to avoid crusting and off-powder phenomena, improve resistance to shrinkage, cracking and vertical flow, and to improve the work efficiency since the painting job is comfortable and saves effort.

2. Bio-Stability Property: Hydroxypropyl MethylCellulose has many features such as thickening power, salt discharge performance, pH stability, water retention, excellent film-forming properties, extensive resistance to enzymes, dispersion and adhesion.In water based paints and coatings, Hydroxypropyl MethylCellulose acts as film-forming agents, thickeners, emulsifiers and stabilizers, making the coating film with good wear resistance, leveling property, and adhesion, and improving the surface tension, pH stability, and compatibility with metal color materials. In the water-based paints, Hydroxypropyl MethylCellulose has excellent storage stability, maintains uniform viscosity, makes pigments uniformly dispersed, and basically won’t be affected by the pH value.

3. Disperse Property: In the production of synthetic resin, Hydroxypropyl MethylCellulose plays the role of protective colloidal agents and can effectively prevent polymeric particles from agglomerating. In the floating polymerization of vinyl chloride (VC), the disperse system has a direct impact on the product, PVC resin, and the quality of processing and products. It helps to improve the thermal stability of the resin and control the particle size distribution(that is, adjust the density of PVC). PVC resins made from high-quality cellulose ethers not only can ensure that the performance meets international standards, but also have apparent physical properties, fine particle characteristics and excellent melting rheological behavior.

4. Thickening Property: Hydroxypropyl MethylCellulose mainly functions as the thickening agent and can increase the the tensile strength and flexural strength. It also helps to improve surface coatings, enhance adhesion and improve the bonding strength of mortar. Furthermore, good permeability can improve the uniformity of the interface, enhance lubricity and fluidity of mortar, make coating easier and thus improve work efficiency.

5. Construct Property: In the bonding of tiles, tile adhesives can function as water-retaining agent and adhesives, and can greatly improve construction performance of adhesives, allow longer opening hours and greater cohesion, and prevent falling of tiles due to excessive water loss. Hydroxypropyl MethylCellulose has the properties of improving the workability, good water-retaining property, enhancing adhesion and high resistance to hanging. Hydroxypropyl MethylCellulose can improve the sticking and tiling efficiency, and also enhance bonding strength and shear strength.


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