- What is the main use of hydroxypropyl methylcellulose (HPMC)?
A: HPMC is widely used in construction materials, coatings, synthetic resins, ceramics, medicine, food, textiles, agriculture, cosmetics, tobacco and other industries. According to the use, HPMC can be divided into: building grade, food and pharmaceutical grade. In the construction class, the amount of putty powder is very large, about 80% is used for making putty powder, and the rest is used as cement mortar and construction glue.
- How to judge the quality of hydroxypropyl methylcellulose (HPMC) simply and intuitively?
A: Whiteness: Although whiteness does not determine whether HPMC is easy to use, and if it is added to the brightener during the production process, it will affect its quality. However, good products are mostly white.
Fineness: HPMC has a fineness of 80 mesh and 100 mesh, and HPMC has a mesh size of 80 mesh. Generally, the finer the fineness, the faster the dissolution.
Transmittance: Put hydroxypropyl methylcellulose (HPMC) in water to form a transparent colloid, and look at its transparency. The better the transmittance, the less insoluble matter. The vertical reactor has a good permeability, and the horizontal reactor is worse, but it does not mean that the quality of the vertical reactor is better than that of the kettle. The quality of the product is determined by many factors.
Specific gravity: The specific gravity is moderate. If the proportion is too large or too small, it may be the result of the production process without control.
- Hydroxypropyl methylcellulose (HPMC) is divided into several types. What is the difference in its use?
A: HPMC can be divided into fast-dissolving type and hot-dissolving type [also called insoluble type]. The instant product is rapidly dispersed in cold water and disappears into the water. At this time, the liquid has no viscosity because HPMC is only dispersed in water and there is no real dissolution. About 2 minutes, the viscosity of the liquid gradually became larger, forming a transparent viscous colloid. Hot-dissolved, in cold water, but in hot water, quickly disperse, disappear in hot water, until the temperature drops to a certain temperature, the viscosity slowly appears until a transparent viscous colloid is formed. The reason for encountering cold water is that the outer cellulose powder encounters cold water, immediately starts to viscous, thickens into a transparent colloid, and the cellulose inside is not in contact with water, and is surrounded by the colloid, or is powdery. But slowly will melt away. Hot-dissolved products do not need to use hot water in practical applications, because the putty powder or mortar is a solid powder. After dry mixing, the cellulose is separated by other materials. When it meets water, it will immediately become viscosity and will not hold the mass. . The hot-dissolved type can only be used in putty powder and mortar. In liquid glue and paint, there will be a phenomenon of clumping, which cannot be used. It is available in a wide range of applications, in putty powder and mortar, as well as in liquid glues and coatings. There are no contraindications. However, water retention and stability are not comparable to hot-melt products. Therefore, in dry powders such as putty powder and mortar, we recommend hot-melt products [insoluble type].
- What are the dissolution methods of hydroxypropyl methylcellulose (HPMC)?
Answer: Hot water dissolution method: Since HPMC is not dissolved in hot water, the initial HPMC can be uniformly dispersed in hot water and then quickly dissolved during cooling. Two typical methods are described as follows:
The required amount of hot water is placed in the container and heated to about 70 °C. Hydroxypropyl methylcellulose was gradually added with slow stirring, and the HPMC floated on the surface of the water, and then a slurry was gradually formed, and the slurry was cooled with stirring.
Adding 1/3 or 2/3 of the required amount of water to the vessel and heating to 70 ° C, dispersing HPMC according to 1) to prepare a hot water slurry; then adding the remaining amount of cold water to the hot water slurry The mixture was cooled after stirring.
Powder mixing method: the HPMC powder is mixed with a large amount of other powdery substances, mixed thoroughly with a blender, and then dissolved with water. At this time, HPMC can be dissolved without agglomeration, because each small small corner has only a little HPMC. The powder will dissolve immediately upon contact with water. – This method is used by putty powder and mortar manufacturers.
- What is the amount of hydroxypropyl methylcellulose (HPMC) in putty powder?
A: The amount of HPMC used in practical applications is different depending on the climate environment, temperature, gray calcium quality, formula of putty powder and product market positioning. In general terms, between 3 kg and 5 kg. For example: in the northern region, the weather is dry, the quality of gray calcium is poor, most put 4-5 kg; Yunnan’s heavy volume is small, generally 3 kg -4 kg; Jiangxi and Fujian have less volume, generally about 3 kg and so on.
- What is the viscosity of hydroxypropyl methylcellulose (HPMC)?
A: Putty powder is generally 100,000. When the temperature is low in winter, it will be better to use some 75,000 viscosity. The mortar is generally 100,000, which is the higher requirement of polystyrene particles. It is recommended to use 150,000 viscosity. Moreover, the most important role of HPMC is to retain water, followed by thickening. In the putty powder, as long as the water retention is good, the viscosity is lower (7-8 million), or even 30,000-50,000, it is ok, of course, the viscosity is larger, the relative water retention is better. In the application of glue, it is more cost-effective to use some of the viscosity, and the amount will be less.
- What are the main technical indicators of hydroxypropyl methylcellulose (HPMC)?
A: hydroxypropyl content, methoxy content, viscosity, moisture and ash, these five indicators. The ratio of hydroxypropyl content to methoxy content should be appropriate, water retention will be good, not just which indicator is high. Viscosity: When the viscosity is less than 100,000, the water retention increases with increasing viscosity. However, if the viscosity exceeds 100,000, the effect on water retention is small. Another important indicator is ash. The popular one can be understood as the impurity of the product. The lower the ash, the higher the purity and the better the product. The general product ash is about 5%, and the domestic quality is better, the ash is about 2-3 percentage points.
- What are the main raw materials for hydroxypropyl methylcellulose (HPMC)?
A: The main raw materials of hydroxypropyl methylcellulose (HPMC): refined cotton, methyl chloride, propylene oxide, caustic soda, other raw materials such as acid, toluene, isopropanol and so on.
- What is the main role of HPMC in the application of putty powder? Is there a chemical?
A: Hydroxypropyl methylcellulose (HPMC) plays a role in thickening, water retention and construction in putty powder. Thickening: Cellulose can be thickened to suspend, keep the solution evenly uniform, and resist sag. Water retention: The putty powder is dried slowly, and the auxiliary gray calcium reacts under the action of water. Construction: Cellulose has a lubricating effect, which can make the putty powder have good workability. HPMC does not participate in any chemical reactions and only plays a supporting role. Putty powder with water, on the wall, is a chemical reaction with the formation of new substances. The main components of ash calcium powder are: Ca(OH)2, a mixture of CaO and a small amount of CaCO3, CaO+H2O=Ca(OH)2-Ca(OH)2+CO2=CaCO3↓+H2O ash calcium in water and air Under the action of CO2, calcium carbonate is formed, and HPMC only retains water, assists the better reaction of ash calcium, and does not participate in any reaction itself.
10, HPMC is a non-ionic cellulose ether, so what is non-ion?
A: Generally speaking, non-ion is a substance that does not ionize in water. Ionization refers to the process by which an electrolyte is dissociated into a freely moving charged ion in a specific solvent such as water or alcohol. For example, the salt that is eaten every day, sodium chloride (NaCl), is ionized to produce free-moving sodium ions (Na+) positively charged and chloride (Cl) negatively charged.
That is to say, HPMC is placed in water and does not dissociate into charged ions, but exists in the form of molecules.
- What is the gel temperature of hydroxypropyl methylcellulose?
A: The gel temperature of HPMC is related to its methoxy content. The lower the methoxy content, the higher the gel temperature.
- Does the powder of putty powder have any relationship with HPMC?
A: The powder of putty powder is mainly related to the quality of gray calcium, and has little to do with HPMC. The low calcium content of ash calcium and the inappropriate ratio of CaO and Ca(OH)2 in ash calcium will cause powder loss. If it is related to HPMC, then HPMC’s water retention is very poor, it will also cause powder.
- What is the difference between the cold water instant type and the hot soluble type of hydroxypropyl methylcellulose in the production process?
A: HPMC’s cold water instant type is treated with glyoxal surface, and it is quickly dispersed in cold water, but it is not really dissolved. The viscosity is up, and the aqueous solution becomes clear and transparent, which is the real dissolution. The hot soluble form is not surface treated with glyoxal. When the amount of glyoxal is large, the dispersion is fast, but the viscosity is slow, and the amount is small.
- What is the smell of hydroxypropyl methylcellulose (HPMC)?
Answer: HPMC produced by solvent method uses toluene and isopropanol as solvents. Sometimes it is not very good to wash, and it will have some residual taste.
- What is the alias of hydroxypropyl methylcellulose?
A: Hydroxypropyl methylcellulose, English: Hydroxypropyl Methyl Cellulose Abbreviation: HPMC or MHPC Alias: hypromellose; cellulose hydroxypropyl methyl ether; Hypromellose, Cellulose, 2-hydroxypropyl methyl Cellulose ether.
- Formula for interior and exterior wall putty powder?
Answer: Heavy calcium 700-800KG Gray calcium 300-200KG HPMC4-5KG (starch ether, pure green, penmine soil, citric acid, polyacrylamide, etc. can be added as appropriate). Exterior wall putty powder: cement 350KG heavy calcium 500KG quartz sand 150KG latex powder 8-12KG cellulose ether 4-6KG starch ether 0.5KG wood fiber 2KG. (The formula is for reference only, the specific construction should be adjusted according to the geographical and actual conditions).
- Does the putty powder on the wall have a relationship with HPMC?
A: HPMC plays the role of thickening, water retention and construction in the putty powder. Not involved in any chemical reactions. The reason for the bubble:
- Put too much water.
2, the bottom layer is not dry, just scrape a layer on the top, it is also easy to foam.
3, the reason for the wall, uneven cement wall, the most easy to foam.
- What is the relationship between viscosity and temperature of HPMC? What should be paid attention to in practical application?
A: The viscosity of HPMC is inversely proportional to temperature, that is, the viscosity increases with decreasing temperature. The viscosity of a product we usually say refers to the result of testing a 2% aqueous solution at 20 degrees Celsius. In practical applications, areas with large temperature differences between summer and winter should be noted. It is recommended to use a relatively low viscosity during the winter, which is more conducive to construction. Otherwise, when the temperature is low, the viscosity of cellulose will increase, and when it is scraped, the hand feel will be heavy.
- What should I pay special attention to in the application of HPMC in plastering?
A: HPMC is divided into instant type and insoluble type. In the application of plastering plaster, only insoluble type can be used. Because the sulfate in the gypsum reacts chemically with the fast-dissolving product.
- What is the level of hydroxypropyl methylcellulose ash?
Answer: Ash is also called burning residue. Simple can be understood as impurities in the product. The production process will naturally occur. After the product comes out of the etherification reactor, it will enter the neutralization kettle. In the neutralization kettle, the pH value will be adjusted first, and then the hot water will be added for washing. The more hot water is added. The more the number of washings, the lower the ash and vice versa.
- The dissolution time of the cold water instant type product (with S), that is, the speed of the viscosity after dispersing in water, what factors are affected?
Answer: 1. Temperature. The lower the temperature, the faster the dissolution, that is, the faster the viscosity comes up.
2, PH value. For rapid dissolution, the pH can be adjusted to 8-10 with ammonia or alkaline water, and the product will dissolve quickly to form a solution. In an acidic environment, the viscosity will be slow. In practical application, the putty powder, gray calcium is alkaline, the product will dissolve quickly, so in the production of putty powder, the dissolution time of hydroxypropyl methylcellulose is no problem, but in the putty powder In production, it is not recommended to use cold water instant type products. It is recommended to use hot soluble (not fast soluble) products.
