1. What is the main purpose of hydroxypropyl methyl cellulose (HPMC)?
HPMC is widely used in construction materials, coatings, synthetic resins, ceramics, medicine, food, textiles, agriculture, cosmetics, tobacco and other industries. HPMC can be divided into construction grade, food grade and medical grade according to its purpose. At present, most domestic products are of construction grade. In construction grade, putty powder is used in a large amount, about 90% is used for putty powder, and the rest is used for cement mortar and glue.
2. There are several types of hydroxypropyl methyl cellulose (HPMC). What is the difference between their uses?
HPMC can be divided into instant type and hot-melt type. The instant type products are quickly dispersed in cold water and disappear in the water. At this time, the liquid has no viscosity, because HPMC is only dispersed in water without real dissolution. About 2 minutes, the viscosity of the liquid gradually increased, forming a transparent viscous colloid. The hot-melt product, when it meets cold water, it can disperse quickly in hot water and disappear in hot water. When the temperature drops to a certain temperature, the viscosity slowly appears until a transparent viscous colloid is formed. Hot-melt type can only be used in putty powder and mortar. In liquid glue and paint, clumping occurs and cannot be used. The instant type has a wider range of applications. It can be used in putty powder and mortar, as well as in liquid glue and paint. There is no contraindication.
3. What are the dissolution methods of hydroxypropyl methylcellulose HPMC?
Hot water dissolution method: Since HPMC does not dissolve in hot water, HPMC can be uniformly dispersed in hot water at the initial stage, and then quickly dissolve during cooling. Two typical methods are described as follows:
1). Add 1/3 or 2/3 of the required amount of water into the container and heat it to 70°C. disperse HPMC to prepare hot water slurry; then add the remaining amount of cold water to hot water In the slurry, cool the mixture after stirring.
Powder mixing method: mix HPMC powder with a large amount of other powdery materials, mix thoroughly with a blender, and then add water to dissolve, then HPMC can be dissolved at this time without clumping and agglomerating, because each tiny corner, there is only a little bit of HPMC The powder will dissolve immediately when it meets water. -Putty powder and mortar manufacturers use this method. [Hydroxypropyl methyl cellulose (HPMC) is used as a thickener and water-retaining agent in putty powder mortar.
Put the required amount of hot water in the container and heat it to about 70°C. Gradually add hydroxypropyl methylcellulose with slow stirring, start HPMC floating on the surface of the water, and then gradually form a slurry, and cool the slurry with stirring.