1, what is the main use of hydroxypropyl methyl cellulose (HPMC)?
HPMC is widely used in building materials, coatings, synthetic resins, ceramics, medicine, food, textile, agriculture, cosmetics, tobacco and other industries. HPMC can be divided into: construction grade, food grade and medical grade by use. At present, most of the domestic construction grade, in the construction grade, putty powder dosage is large, about 90% is used to make putty powder, the rest is used to make cement mortar and glue.
2, hydroxypropyl methyl cellulose (HPMC) is divided into several, what is the difference in its use?
HPMC can be divided into instant solution-type and hot solution-type, instant solution-type products, quickly dispersed in cold water, disappear in the water, at this time the liquid has no viscosity, because HPMC is just dispersed in the water, no real dissolution. About 2 minutes, the viscosity of the liquid slowly increases, forming a transparent viscous colloid. Hot soluble products, in cold water, can be quickly dispersed in hot water, disappear in hot water, when the temperature drops to a certain temperature, viscosity slowly appears, until the formation of transparent viscous colloid. Hot solution can only be used in putty powder and mortar, in the liquid glue and paint, there will be a group phenomenon, can not be used. Instant SOLUTION MODEL, RANGE OF APPLICATION IS A FEW WIDER, IN BE BORED WITH CHILD POWDER AND MORTAR, AND IN LIQUID GLUE AND COATING, ALL CAN USE, WITHOUT what CONTRAINDICATION.
3, hydroxypropyl methyl cellulose (HPMC) solubility methods have those?
Hot water dissolution method: Because HPMC is not dissolved in hot water, so early HPMC can be evenly dispersed in hot water, then quickly dissolved when cooled, two typical methods are described as follows:
1) Put the required amount of hot water into the container and heat it to about 70℃. Gradually add hydroxypropyl methylcellulose under slow stirring, HPMC began to float on the surface of the water, and then gradually form a slurry, under stirring cooling the slurry.
2), add the required amount of 1/3 or 2/3 water in the container, and heat to 70℃, according to the method of 1), HPMC dispersion, preparation of hot water slurry; Then add the remaining amount of cold water to the hot slurry, stir and cool the mixture.
Powder mixing method: HPMC powder and a large number of other powdery material ingredients, thoroughly mixed with a blender, after adding water to dissolve, then HPMC can dissolve at this time, but not cohesion, because each small corner, only a little HPMC powder, water will immediately dissolve. – 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 powder mortar.
4, how simple and intuitive to determine the quality of hydroxypropyl methyl cellulose (HPMC)?
(1) whiteness: although whiteness can not determine whether HPMC is easy to use, and if it is added in the production process of whitening agent, will affect its quality. However, good products are mostly white.
(2) fineness: HPMC fineness generally 80 mesh and 100 mesh, 120 less purpose, Hebei HPMC mostly 80 mesh, the finer the fineness, generally the better.
(3) transmittance: the hydroxypropyl methyl cellulose (HPMC) into the water, the formation of a transparent colloid, see its transmittance, the greater the transmittance, the better, the less insoluble material inside. The permeability of the vertical reactor is generally good, the horizontal reactor is worse, but can not show that the quality of the vertical reactor production is better than that of the horizontal reactor production, product quality is determined by many factors.
(4) specific gravity: the greater the specific gravity, the heavier the better. Than significant, generally because the content of hydroxypropyl is high, hydroxypropyl content is high, then water retention is better.
5, hydroxypropyl methyl cellulose (HPMC) in the amount of putty powder?
HPMC in the actual application of the dosage, by the climate environment, temperature, local calcium ash quality, putty powder formula and “customer requirements of quality”, and have different. Generally speaking, between four and five kilograms. For example: Beijing putty powder, mostly put 5 kg; In Guizhou, most of them are 5 kg in summer and 4.5 kg in winter. Yunnan’s quantity is small, generally 3 kg -4 kg and so on.
6, hydroxypropyl methyl cellulose (HPMC) how much viscosity is appropriate?
Be BORED WITH CHILD POWDER IS GENERAL 100 THOUSAND OK, THE REQUIREMENT IN MORTAR IS SOME TALLER, WANT 150 THOUSAND ABILITY TO USE. Moreover, the most important role of HPMC is water retention, followed by thickening. In putty powder, as long as the water retention is good, the viscosity is low (7-80 thousand), it is also possible, of course, the viscosity is larger, the relative water retention is better, when the viscosity is more than 100 thousand, the viscosity has little effect on the water retention.
7, hydroxypropyl methyl cellulose (HPMC) what are the main technical indicators?
Hydroxypropyl content and viscosity, most users are concerned with these two indexes. Hydroxypropyl content is high, water retention is generally better. Viscosity, water retention, relative (but not absolute) is also better, and viscosity, in cement mortar better use some.
8, hydroxypropyl methyl cellulose (HPMC) the main raw materials are what?
Hydroxypropyl methyl cellulose (HPMC) the main raw materials: refined cotton, chloromethane, propylene oxide, other raw materials, tablets alkali, acid, toluene, isopropyl alcohol and so on.
9, HPMC in the application of putty powder, what is the main role, whether chemistry?
HPMC in putty powder, thickening, water retention and construction of three roles. Thickening: Cellulose can be thickened to play a suspension, so that the solution to maintain uniform up and down the same role, anti flow hanging. Water retention: make putty powder dry more slowly, auxiliary ash calcium reaction under the action of water. Construction: Cellulose has lubricating effect, can make putty powder has good construction. HPMC does not participate in any chemical reactions, only plays an auxiliary role. Putty powder added water, on the wall, is a chemical reaction, because there is the generation of new material, putty powder on the wall down from the wall, ground into powder, and then used, it is no longer, because has formed a new material (calcium carbonate). The main components of grey 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 calcium ash in water and air under the action of CO2, the formation of calcium carbonate, and HPMC only water retention, auxiliary calcium ash better reaction, its own did not participate in any reaction.
10, HPMC non-ionic cellulose ether, then what is non-ionic?
In general terms, nonionic is something that doesn’t ionize in water. Ionization is the process by which an electrolyte is dissociated into freely moving charged ions in a specific solvent, such as water or alcohol. For example, sodium chloride (NaCl), the salt we eat every day, dissolves in water and ionizes to produce free-moving sodium ions (Na+) that are positively charged and chloride ions (Cl) that are negatively charged. In other words, HPMC in water does not dissociate into charged ions, but exists as molecules.
11, hydroxypropyl methylcellulose gel temperature and what is related to?
HPMC gel temperature is related to its methoxy content, the lower the methoxy content ↓, the higher the gel temperature ↑.
12. Is there any relationship between putty powder and HPMC?
Putty powder powder and the quality of calcium has a great relationship, and HPMC does not have too much relationship. The low calcium content of calcium and the proportion of CaO, Ca(OH)2 in calcium ash is not appropriate, will cause powder drop. If it has something to do with HPMC, then the water retention of HPMC is poor, it will also cause powder drop. For specific reasons, please see question 9.
13, hydroxypropyl methylcellulose cold water soluble type and hot soluble type in the production process, what is the difference?
HPMC cold water soluble type is after glyoxal surface treatment, in cold water quickly dispersed, but not really dissolved, viscosity up, is dissolved. The heat-soluble type was not surface treated with glyoxal. The volume of glyoxal is large, the dispersion is fast, but the viscosity is slow, the volume is small, on the contrary.
14, hydroxypropyl methyl cellulose (HPMC) has the smell of what is going on?
HPMC produced by solvent method is made of toluene and isopropyl alcohol as solvent. If the washing is not very good, there will be some residual taste.
15, different uses, how to choose the right hydroxypropyl methyl cellulose (HPMC)?
The APPLICATION OF putty powder: the requirement is lower, the viscosity is 100 thousand, it is OK, the important thing is to keep water better. Application of mortar: the requirement is higher, the requirement is high viscosity, 150 thousand should be better. Application of glue: need instant products, high viscosity.
16, hydroxypropyl methylcellulose what is the alias?
Hydroxypropyl Methyl Cellulose, English: Hydroxypropyl Methyl Cellulose abbreviation: HPMC or MHPC alias: Hydroxypropyl Methyl Cellulose; Cellulose hydroxypropyl methyl ether; Cellulose hydroxypropyl Methyl ether Hypromellose, 2-hydroxypropylmethyl Cellulose ether. Cellulose hydroxypropyl Methyl ether Hyprolose.
17, HPMC in the application of putty powder, putty powder bubble what reason?
HPMC in putty powder, thickening, water retention and construction of three roles. Not participating in any reaction. The reason for the bubbles: 1, the water put too much. 2, the bottom is not dry, on the top and scrape a layer, also easy to bubble.
18. Putty powder formula for interior and exterior walls?
Putty powder for inner wall: 800KG of heavy calcium and 150KG of grey calcium (starch ether, pure green, peng soil, citric acid and polyacrylamide can be added appropriately)
Exterior wall putty powder: cement 350KG heavy calcium 500KG quartz sand 150KG latex powder 8-12kg cellulose ether 3KG starch ether 0.5kg wood fiber 2KG
19. What is the difference between HPMC and MC?
MC is methyl cellulose, refined cotton after alkali treatment, with methane chloride as etherification agent, through a series of reactions to make cellulose ether. Generally, the degree of substitution is 1.6~2.0, and the solubility varies with the degree of substitution. It is a non-ionic cellulose ether.
(1) The water retention of methyl cellulose depends on its amount of addition, viscosity, particle fineness and dissolution speed. Generally add large amount, small fineness, viscosity, high water retention rate. Among them, the amount of added to the water retention rate has the greatest impact, the viscosity and the level of water retention rate is not proportional to the relationship. The dissolution rate mainly depends on the surface modification degree and particle fineness of cellulose particles. In the above cellulose ether, methyl cellulose and hydroxypropyl methyl cellulose water retention rate is higher.
(2) Methyl cellulose can be dissolved in cold water, hot water dissolved will encounter difficulties, its aqueous solution in the pH=3~12 range is very stable. It has good compatibility with starch, guanidine gum and many surfactants. Gelation occurs when the temperature reaches the gelation temperature.
(3) The change of temperature will seriously affect the water retention rate of methyl cellulose. Generally, the higher the temperature, the worse the water retention. If the mortar temperature exceeds 40℃, the water retention of methyl cellulose will be significantly worse, seriously affecting the construction of mortar.
(4) Methyl cellulose has obvious influence on the construction and adhesion of mortar. Here, “adhesion” refers to the adhesive force felt between the worker’s application tool and the wall substrate, that is, the shear resistance of the mortar. The adhesive property is large, the shear resistance of mortar is large, and the force required by workers in the process of use is also large, so the construction property of mortar is poor. In cellulose ether products, the methyl cellulose adhesion is at a medium level.
HPMC for hydroxypropyl methyl cellulose, is made of refined cotton after alkalization treatment, with propylene oxide and chloromethane as etherifying agent, through a series of reactions and made of non-ionic cellulose mixed ether. The substitution degree is generally 1.2~2.0. Its properties are affected by the proportion of methoxy content and hydroxypropyl content.
(1) hydroxypropyl methyl cellulose soluble in cold water, hot water dissolved will encounter difficulties. But its gelation temperature in hot water is significantly higher than that of methyl cellulose. The solubility of methyl cellulose in cold water is also greatly improved.
(2) the viscosity of hydroxypropyl methyl cellulose is related to its molecular weight, and the large molecular weight is the high viscosity. Temperature will also affect its viscosity, temperature increases, viscosity decreases. However, the viscosity of high temperature is lower than that of methyl cellulose. The solution is stable when stored at room temperature.
(3) hydroxypropyl methyl cellulose is stable to acid and alkali, and its aqueous solution is very stable in the range of pH=2~12. Caustic soda and lime water have no great effect on its properties, but alkali can accelerate its dissolution rate and improve the viscosity of the pin. Hydroxypropyl methyl cellulose has stability to general salts, but when the concentration of salt solution is high, the viscosity of hydroxypropyl methyl cellulose solution tends to increase.
(4) The water retention of hydroxypropyl methyl cellulose depends on the amount of its added, viscosity, etc., the same amount of water retention rate is higher than methyl cellulose.
(5) hydroxypropyl methyl cellulose can be mixed with water-soluble polymer compounds to become a uniform, higher viscosity solution. Such as polyvinyl alcohol, starch ether, plant gum and so on.
(6) The adhesion of hydroxypropyl methyl cellulose to mortar construction is higher than that of methyl cellulose.
(7) hydroxypropyl methyl cellulose has better enzymatic resistance than methyl cellulose, and the possibility of enzymatic degradation of its solution is lower than that of methyl cellulose.
What should be paid attention to in the practical application of the relationship between the viscosity and temperature of HPMC?
The viscosity of HPMC is inversely proportional to temperature, that is to say, the viscosity increases with the decrease of temperature. When we talk about the viscosity of a product, we mean the result of measuring its 2% aqueous solution at a temperature of 20 degrees Celsius.
In practical application, in areas with large temperature difference between summer and winter, attention should be paid to the recommendation to use relatively lower viscosity in winter, which is more conducive to construction. Otherwise, when the temperature is low, the viscosity of cellulose will increase, when scraping, feel will be heavy.
Medium viscosity :75000-100000 mainly used for putty
Reason: good water retention
High viscosity :150000-200000 is mainly used for polystyrene particles thermal insulation mortar powder and glass beads thermal insulation mortar.
Reason: high viscosity, mortar is not easy to drop, flow hanging, improve the construction.
But generally speaking, the higher the viscosity, the better the water retention will be, so many dry mortar factories consider the cost, with medium viscosity cellulose (75,000-100000) to replace low viscosity cellulose (20,000-40000) to reduce the amount of addition.
Post time: Sep-14-2022