1. What is the main use of hydroxypropyl methyl cellulose (HPMC)?
Answer: HPMC is widely used in building materials, coatings, synthetic resins, ceramics, medicine, food, textile, agriculture, cosmetics, tobacco and other industries. HPMC by use can be divided into: construction grade, food grade and pharmaceutical grade. At present, most of the domestic construction grade, in the construction grade, the amount of putty powder glue is very large, about 90% is used to do putty powder, the rest is used to do cement mortar and glue.
2. Hydroxypropyl methyl cellulose (HPMC) is divided into several, what is the difference between its use?
Answer: HPMC can be divided into instant type and hot dissolve type, instant products, in cold water quickly dispersed, disappeared in water, at this time the liquid has no viscosity, because HPMC is just dispersed in water, no real dissolution. After about 2 minutes, the viscosity of the liquid gradually increases, forming a transparent, sticky gel. Hot soluble products, in cold water, can quickly disperse in hot water, disappear in hot water, when the temperature drops to a certain temperature, viscosity slowly appear, until the formation of transparent viscous colloid. Hot soluble type can only be used in putty powder and mortar, in liquid glue and paint, there will be clumping phenomenon, can not be used. Instant type, a wide range of applications, in putty powder and mortar, as well as liquid glue and paint, can be used, there is no taboo&#;
3. What are the dissolution methods of hydroxypropyl methyl cellulose (HPMC)?
Answer: hot water solution method: because HPMC is not dissolved in hot water, so the initial HPMC can be evenly dispersed in hot water, then quickly dissolved when cooling, two typical methods are described as follows:
1) Put the required amount of hot water in the container and heat it to about 70&#;. Under the slow stirring gradually add hydroxypropyl methyl cellulose, HPMC began to float on the surface of the water, and then gradually form a slurry, the slurry cooling under the stirring.
2) Add 1/3 or 2/3 of the required amount of water into the container, and heat to 70&#;, according to the method of 1), disperse HPMC, prepare hot water slurry; Then add the remaining amount of cold water to the hot slurry, stirring and cooling the mixture.
Powder mixing method: HPMC powder and a large number of other powdery material ingredients, mixing fully with a blender, then add water to dissolve, HPMC at this time can dissolve, and do not stick together, because each small corner, only a little bit of HPMC powder, water will dissolve immediately. - Putty powder and mortar production enterprises are using this method. [Hydroxypropyl methyl cellulose (HPMC) is used as thickening agent and water retaining agent in putty mortar.]
4. How to determine the quality of hydroxypropyl methyl cellulose (HPMC) simply and intuitively?
Answer:
1) whiteness: although whiteness can not determine whether HPMC is good, and if it is added in the production process of whitener, will affect its quality. However, good products are mostly white.
2) Fineness: HPMC fineness generally has 80 mesh and 100 mesh, 120 purpose is less, the finer the fineness is generally better.
3) transmittance: the hydroxypropyl methyl cellulose (HPMC) into the water, the formation of transparent colloid, see its transmittance, the greater the transmittance, the better, that less insoluble matter inside.
4) Proportion: the larger the proportion is better. It's usually because it's high in hydroxypropyl,
High hydroxypropyl content, water retention is better.
5. hydroxypropyl methyl cellulose (HPMC) in putty powder amount?
Answer:The amount of construction HPMC in practical application is subject to the climate environment, temperature, local ash calcium quality, putty powder formula to
And "quality required by the customer". Generally speaking, between 4kg and 5kg. For example: Beijing greasy powder, mostly put 5 kg; Most in Guizhou are 5 kg in summer and 4.5 kg in winter; Yunnan has a smaller release,
Generally 3 kg - 4 kg and so on.
6. Is the viscosity of hydroxypropyl methyl cellulose (HPMC) much appropriate?
Answer: putty powder is generally one hundred thousand, mortar in the higher requirements, to use one hundred and fifty thousand. Also, HPMC
The most important function is water retention, followed by thickening. In the putty powder, as long as the water retention is good, the viscosity is lower (70-80 thousand) is also OK, of course, the relative water retention of the larger viscosity is better, when the viscosity is more than 100 thousand, the influence of the viscosity on the water retention is not big.
7. hydroxypropyl methyl cellulose (HPMC) what are the main technical indicators?
Answer: The content and viscosity of hydroxypropyl, most users are concerned about these two indicators. Hydroxypropyl content is high, water retention is generally better. High viscosity, water retention, relative (but not absolute) is better, and high viscosity, better to use in cement mortar.
8. What are the main raw materials of hydroxypropyl methyl cellulose (HPMC)?
Answer: The main raw materials of hydroxypropyl methyl cellulose (HPMC) : refined cotton, chloromethane, propylene oxide, other raw materials and alkali tablets, acid, toluene, isopropyl alcohol and so on.
9. HPMC in putty powder application, the main role of what, whether chemical reaction?
Answer: HPMC in the application of putty powder, thickening, water retention and construction of three roles. Thickening: Cellulose can be thickened to suspension, so that the solution to maintain uniform up and down the role of the same, anti-hanging. Water retention: Make putty powder dry slowly, assist ash calcium reaction under the action of water. Construction: cellulose has lubricating effect, can make putty powder has good construction property. HPMC does not participate in any chemical reactions, but only plays an auxiliary role. Putty powder and water, on the wall, is a chemical reaction, because of the formation of new substances, the putty powder on the wall off the wall, ground into powder and then use, will not work, because a new substance (calcium carbonate) has been formed. The main components of ash calcium powder are: Ca(OH)2, CaO and a small amount of CaCO3 mixture,
CaO+H2O=Ca(OH)2 - Ca(OH)2+CO2=CaCO3&#;+H2O Ash calcium generates calcium carbonate under the action of CO2 in water and air, while HPMC only holds water to assist ash calcium to react better, and itself does not participate in any reaction.
10. HPMC non-ionic cellulose ether, so what is non-ionic?
Answer: In plain English, nonion is a substance that does not ionize in water. Ionization is the process by which electrolytes in a specific solvent (e.g. water, alcohol) are separated into charged ions that can move freely. For example, daily salt, sodium chloride (NaCl), dissolves in water and ionizes to produce freely moving sodium ions with positive charges and chloride ions with negative charges. In other words, HPMC in water does not dissociate into charged ions, but exists as molecules.
11. What is related to the gel temperature of hydroxypropyl methyl cellulose?
Answer: HPMC chemical gel temperature is related to its methoxy content, the lower the methoxy content, the higher the gel temperature
12.Does the powder loss of putty powder have anything to do with HPMC?
Answer: The powder loss of putty powder is mainly related to the quality of hydrated lime (calcium hydroxide) and has little to do with HPMC. A low calcium content in hydrated lime and an inappropriate ratio of CaO to Ca(OH)2 can both cause powder loss. If there is some relation to HPMC, it would be that poor water retention of HPMC can also cause powder loss. For specific reasons, please refer to question 9.
13. What is the difference between the cold water instant type and hot soluble type of hydroxypropyl methyl cellulose in the production process?
Answer: HPMC cold water instant type is after glyoxal surface treatment, in cold water quickly dispersed, but not the real dissolution, viscosity is dissolved. The hot soluble type has not been surface treated with glyoxal. The amount of glyoxal is large, the dispersion is fast, but the viscosity is slow, the amount is small, the opposite.
14.What's the reason for the odor of Hydroxypropyl Methylcellulose (HPMC)?
Answer: HPMC produced through solvent methods uses solvents such as toluene and isopropanol. If the washing process is not thorough, there may be some residual odor.
15. How to choose the appropriate Hydroxypropyl Methylcellulose (HPMC) for different purposes?
Answer: For putty powder applications, a viscosity of 100,000 is sufficient, but good water retention is important. For mortar applications, higher viscosity is required, preferably around 150,000. For adhesive applications, quick-dissolving products with high viscosity are needed.
16. What are the alternative names for Hydroxypropyl Methylcellulose?
Answer: Hydroxypropyl Methylcellulose, in English, is abbreviated as HPMC or MHPC. It is also known as hydroxypropyl methyl cellulose, hydroxypropyl methylcellulose ether, Hypromellose, Cellulose 2-hydroxypropylmethyl, and Cellulose hydroxypropyl methyl ether, Hyprolose.
17.Application of HPMC in putty powder and the reasons for bubble formation in putty powder?
Answer: HPMC serves three functions in putty powder: thickening, water retention, and facilitating construction. It does not participate in any chemical reactions. The reasons for bubble formation are as follows:
1)Excessive water content.
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2)Applying another layer on top before the underlying layer has dried, which can also lead to bubbling.
18.Formulas for interior and exterior wall putty powder?
Answer:
1)Interior wall putty powder: 800KG heavy calcium, 150KG hydrated lime (additional options may include starch ether, pure Qing, Peng Run soil, citric acid, polyacrylamide, etc.).
2)Exterior wall putty powder: 350KG cement, 500KG heavy calcium, 150KG quartz sand, 8-12KG latex powder, 3KG cellulose ether, 0.5KG starch ether, 2KG wood fiber.
19.What is the difference between HPMC and MC?
Answer: MC stands for Methyl Cellulose, which is derived from refined cotton treated with alkali. It is then etherified using methyl chloride as the etherifying agent, resulting in cellulose ether through a series of reactions. The degree of substitution is generally between 1.6 and 2.0, and different degrees of substitution result in different solubilities. It belongs to the nonionic type of cellulose ether.
1)The water retention of Methyl Cellulose depends on the dosage, viscosity, particle size, and dissolution rate. Generally, higher dosage, smaller particle size, and higher viscosity result in better water retention. Among various cellulose ethers, Methyl Cellulose and Hydroxypropyl Methylcellulose exhibit higher water retention.
2)Methyl Cellulose is soluble in cold water, while dissolution in hot water can be challenging. Its aqueous solution is highly stable within a pH range of 3 to 12. It has good compatibility with starch, guar gum, and many surfactants. Gelation occurs when the temperature reaches the gelation temperature.
3)Temperature variations significantly affect the water retention of Methyl Cellulose. Generally, higher temperatures result in poorer water retention. If the temperature of the mortar exceeds 40&#;, the water retention of Methyl Cellulose deteriorates, adversely affecting the workability of the mortar.
4)Methyl Cellulose has a noticeable impact on the workability and adhesion of mortar. "Adhesion" here refers to the adhesive force felt between the worker's application tool and the substrate. Greater adhesion leads to higher shear resistance and requires more force during application, resulting in decreased workability. In terms of cellulose ether products, Methyl Cellulose exhibits moderate adhesion.
HPMC, on the other hand, is Hydroxypropyl Methylcellulose. It is produced by alkali treatment of refined cotton and further etherified using epichlorohydrin and chloromethane as etherifying agents, resulting in a nonionic mixed ether of cellulose. The degree of substitution is typically between 1.2 and 2.0, and its properties vary based on the ratio of methoxy and hydroxypropoxy groups.
1)Hydroxypropyl Methylcellulose is soluble in cold water, while dissolution in hot water can be challenging. However, its gelation temperature in hot water is significantly higher than that of Methyl Cellulose. Compared to Methyl Cellulose, Hydroxypropyl Methylcellulose shows improved solubility in cold water.
2)The viscosity of Hydroxypropyl Methylcellulose is influenced by its molecular weight, with higher molecular weight leading to higher viscosity. Temperature also affects its viscosity, with viscosity decreasing as temperature rises. However, the impact of temperature on viscosity is lower compared to Methyl Cellulose. Its solution is stable when stored at room temperature.
3)Hydroxypropyl Methylcellulose exhibits stability in acidic and alkaline conditions, with its aqueous solution remaining stable within a pH range of 2 to 12. It is minimally affected by sodium hydroxide and lime water, but alkaline conditions can accelerate its dissolution and slightly increase viscosity. Hydroxypropyl Methylcellulose demonstrates stability in the presence of common salts, although at higher salt concentrations, there is a tendency for increased viscosity in its solution.
4)The water retention of Hydroxypropyl Methylcellulose depends on factors such as dosage and viscosity. Under the same dosage, it exhibits higher water retention compared to Methyl Cellulose.
5)Hydroxypropyl Methylcell.
20. The relationship between HPMC viscosity and temperature should be taken into account in practical applications?
Answer: HPMC viscosity is inversely proportional to temperature, meaning that viscosity increases as temperature decreases. When we refer to the viscosity of a product, it typically indicates the measurement of its 2% aqueous solution at a temperature of 20 degrees Celsius.
In regions with significant temperature differences between summer and winter, it is advisable to use lower viscosity HPMC during the winter season for better construction results. Otherwise, at lower temperatures, the viscosity of the cellulose increases, resulting in a heavier feel during application and scraping.
Medium viscosity (75,000-100,000) is primarily used for putty, as it provides good water retention.
High viscosity (150,000-200,000) is mainly used for polystyrene particle insulation mortar powder and vitrified microbead insulation mortar. The higher viscosity helps prevent mortar from dusting and sagging, improving the construction process.
However, in general, higher viscosity results in better water retention. Therefore, many dry mortar manufacturers opt for medium viscosity cellulose (75,000-100,000) as a substitute for low-medium viscosity cellulose (20,000-40,000) to reduce the required dosage, considering cost factors.
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