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  • Effect of hydroxypropyl methyl cellulose on the improvement of cement based materials

    Effect of hydroxypropyl methyl cellulose on the improvement of cement based materials

    In recent years, with the continuous development of external wall insulation technology, the continuous progress of cellulose production technology, and the excellent characteristics of HPMC itself, hydroxypropyl methyl cellulose HPMC has been widely applied in the construction industry. In order to study the mechanism of HPMC and cement-based materials, the improvement effect of HPMC on the cohesive properties of cement based materials was studied in this paper. setting time The setting time of the concrete is mainly related to the setting time of cement, aggregate has little effect, so can be used to replace the setting time of mortar HPMC on non dispersible underwater concrete setting time, the setting time of mortar by water cement ratio, cement sand ratio, so in order to evaluate the effect of HPMC on setting time mortar, mortar fixed water cement ratio and cement sand ratio. The experimental reaction showed that the addition of HPMC had a significant retardation effect on the mortar mixture. With the increase of HPMC content, the setting time of mortar had been prolonged. Under the same HPMC dosage, the underwater molding mortar was longer than the molding time in the air. When measured in water, the setting time of HPMC mixed mortar is 6~18 h, and the final setting delay 6~22 h is delayed compared with the blank test. So HPMC should be used in combination with the early strength agent. HPMC is a high molecular polymer. It is a large molecular linear structure with a hydroxyl group on the functional group. It can form a hydrogen bond with the mixed water molecules to increase the viscosity of the mixed water. The long molecular chains of HPMC will attract each other and bind the HPMC molecules to form a network structure and wrap the cement and mixing water. Because HPMC forms a network structure similar to the thin film and cement wrapping effect, it can effectively prevent the evaporation of moisture in mortar and retard or slow down the hydration speed of cement. Bleeding Bleeding of mortar and concrete are similar, will cause the aggregate settlement is serious, leading to the top of slurry water cement ratio increases, the slurry and plastic shrinkage cracking in the early, large, and slurry surface strength is relatively weak. When the content is above 0.5%, the basic no longer bleeding phenomenon. This is because when HPMC is mixed into mortar, HPMC has membrane and network structure, and the adsorption of hydroxyl on macromolecule long chain. It makes flocculation form of cement and mixing water in mortar, and ensures the stable structure of mortar. After adding HPMC in the mortar, many independent and tiny bubbles will be formed. These bubbles are evenly distributed in the mortar and impede the deposition of the aggregate. This technology has a great influence on the properties of HPMC cement based materials, such as dry mortar, often used to prepare polymer mortar cement based composite material, which has good water retention, water resistance. Water requirement of mortar When the amount of HPMC is very small, it has a great influence on the water requirement of the mortar. When the expansion degree of fresh mortar is basically the same, the amount of HPMC and mortar water demand change linearly within a certain time period, and the water demand of mortar decreases first and then increases obviously. The HPMC content is less than 0.025%, with the increase of dosage, the same degree of expansion conditions, reduce the water requirement of mortar, which indicates that the HPMC content is small water reducing effect on mortar, air entraining effect with HPMC, make the mortar there are lots of tiny independent bubble, these bubbles lubricates the. Mortar fluidity improved. When the dosage is more than 0.025%, the water demand of mortar increases with the increase of volume. This is due to the further completion of the reticular structure of HPMC, the shortened flocculation space on the long molecular chain, the attraction and cohesiveness of mortar, and the decrease of mortar fluidity. Therefore, in the case of the same expansion degree, the slurry shows the increase of water requirement.

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  • Is there any relationship between putty powder and hydroxypropyl methyl cellulose?

    Is there any relationship between putty powder and hydroxypropyl methyl cellulose?

    The role of hydroxypropyl methyl cellulose in putty: It plays three roles of thickening, water holding and construction. Thickening: cellulose can be thickened and suspended to keep the solution uniform and up and down. Water retention: make the putty dry more slowly and assist the lime to react under the action of water. Construction: cellulose has a lubrication effect, can make putty powder have good construction. Hydroxypropyl methyl cellulose does not participate in any chemical reaction and only plays an auxiliary role. Putty powder adding water, batch wall, is a chemical reaction, because of the formation of new material calcium carbonate. The main ingredients are: ash calcium hydroxide Ca (OH) 2, CaO and a small amount of calcium carbonate and calcium oxide The mixture of CaCO3, calcium carbonate, under the action of CO2 in water and air, is made of calcium carbonate. The hydroxypropyl methyl cellulose only protects the water, assists the lime calcium to react better, and does not take part in any reaction itself. We start from the raw material to analyze the putty putty powder out reason: ash, hydroxypropyl methyl cellulose, calcium carbonate, water Sierozem 1, in the actual production, in order to speed up the decomposition of plant ash, calcination temperature often increased to 1000~1100 DEG C. Because of the large size of the limestone material or the uneven temperature distribution in the calcined kiln, the lime is often contained in the lime. No fire lime and excessive lime. Calcium carbonate in underfired lime is not fully decomposed, and it is incapable of giving enough to putty. The bonding strength leads to the depowling caused by the insufficient hardness of the putty. The content of calcium hydroxide in 2, ash higher hardness produced better putty, and ash in The lower the content of calcium hydroxide, the worse the hardness of the putty in the production place, which causes the problem of powdered depowdered powder. 3, a large number of ash incorporation caused heavy calcium powder, ash content is too low to provide enough. The hardness of the putty makes the putty powder. Hydroxypropyl methyl cellulose The main effect of hydroxypropyl methyl cellulose in the putty powder in the water, sufficient water for ash hardening, guarantee The hardening effect is full. If the quality of hydroxypropyl methyl cellulose has a problem or low effective content, it can not provide sufficient moisture and cause hardening. It is not enough to make the putty powder. From the above, it is found that hydroxypropyl methylcellulose does not have a certain effect in the powder of putty powder, and the powder will be dropped by the putty powder. The main reason is the ash calcium carbonate...

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  • Viscosity control of hydroxypropyl methyl cellulose

    Viscosity control of hydroxypropyl methyl cellulose

    The purity of the change can be adjusted from the washing process. The viscosity and purity of hydroxypropyl methyl cellulose (HPMC) are generally required. The same replace the level, according to the application needs of the product. The viscosity has a certain effect on the gel temperature: the viscosity is low, the gel temperature is high, the viscosity is high, and the gel temperature is low. At the same time, the purity of the product also has a certain effect on the gel temperature, and the salt content is high, and the gel temperature of the product will decrease. The high polymerization degree of cellulose material can be used to increase the viscosity by adding antioxidants. Vacuum evacuation and nitrogen protection can also improve the viscosity of products through the micro crosslinking of the final products. The viscosity of products can be reduced, and cellulose materials with low degree of cohesion can be used, adding oxidants to the alkalization process or etherification process, and also by radiation viscosity reduction.

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  • The influence of those factors on the cold water soluble type of hydroxypropyl methyl cellulose?

    The influence of those factors on the cold water soluble type of hydroxypropyl methyl cellulose?

    The dissolution time of hydroxypropyl methyl cellulose cold water soluble products (with S), which is the viscosity of water after dispersing in water, is influenced by what factors. 1. Temperature. The lower the temperature, the faster the dissolution rate. 2, pH value. In order to quickly dissolve, the pH value of ammonia or alkaline water can be adjusted to 8 - 10, and the product will dissolve quickly and form a solution. In practical application, do putty powder, ash calcium is alkaline, products can be quickly dissolved, so in the production of putty powder, dissolving time of HPMC long no problem, but in the putty powder production, it is not recommended to use cold water instant products, with a hot type suggestion (common type product).

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  • How to determine the quality of hydroxypropyl methylcellulose (HPMC) simply and intuitively?

    How to determine the quality of hydroxypropyl methylcellulose (HPMC) simply and intuitively?

    Judgment point (1) Whiteness: whiteness can not determine whether HPMC is good or not, and if the whitening agent is added to the production process, it will affect its quality. However, most of the good products are in good whiteness. (2) fineness: the fineness of HPMC generally has 80 orders and 100 orders, 120 purposes are less, and most of the HPMC production in Hebei is 80 eyes, the finer the fineness is, the better it is. (3) transmittance: when hydroxypropyl methyl cellulose (HPMC) is put into water to form transparent colloid, its transmittance and transmittance are better. The transmittance of vertical reactor is generally good, and the horizontal reactor is worse. But it can"t explain that the quality of vertical kettle production is better than that of horizontal kettle, and the quality of products is decided by many factors. (4) proportion: the larger the proportion, the better the heavier. In general, it is because the content of hydroxypropyl group is high and the content of hydroxypropyl group is high, so it is better to keep water.

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  • Teach you to distinguish between true and false hydroxypropyl methyl cellulose (HPMC)

    Teach you to distinguish between true and false hydroxypropyl methyl cellulose (HPMC)

    Now the country with the requirement of building energy saving and environmental protection, building additive hydroxypropylmethylcellulose, get more and more building trust, the current domestic HPMC price disparity, quality uneven in quality, water retention, adhesion properties of resulting products are greatly reduced, resulting in many construction quality problems, so it is difficult for clients to make the right choice. There are the following differences between pure HPMC and adulterated HPMC: 1., the pure HPMC has a fluffy appearance and a smaller bulk density. The range is: 0.3-0.4g/ml; the adulterated HPMC has better fluidity and hand feel, which is significantly different from the genuine appearance. 2. pure HPMC aqueous solution clarification, high transmittance, more than 97% water retention rate; HPMC aqueous solution of adulteration of turbidity, water retention rate of 80% is difficult to achieve. 3. pure HPMC should not smell ammonia, starch and alcohols; adulterated HPMC can often smell all kinds of taste, even if it is tasteless, it will feel more heavy. 4. pure HPMC powder is fibrous under a microscope or magnifying glass, and a granular solid or crystal can be observed under an adulterated HPMC under a microscope or magnifying glass. Common adulteration methods and identification methods: 1. of the cellulose ether, which is added to the amide, can make the viscosity of the cellulose ether increase rapidly and can not be identified by the viscometer. Identification method: because of the characteristics of amide, this cellulose ether solution often appears wire drawing phenomenon, while good cellulose ether dissolves without drawing wire phenomenon. The solution is like jelly, so-called sticky but not continuous. 2. cellulose ether that is added to starch. Starch is generally insoluble in water, and the solution is often poor in light transmittance. Identification methods: using iodine drip into cellulose ether solution, the blue color can be considered adding starch. 3. to add polyvinyl alcohol. As we all know, the market price of polyvinyl alcohol (PVA), such as 2488 and 1788, is often lower than that of cellulose ether. The mixed polyvinyl alcohol powder can reduce the cost of cellulose ether. Identification method: the cellulose ether is often granular and has a large density. When the water is dissolved rapidly and the glass rod is used to pick the solution, there will be a more obvious drawing phenomenon. Summary: Because of its special structure and group, its water retention is irreplaceable by other substances. No matter what kind of filler is added, it will greatly reduce its water holding capacity if it is heavily mixed. The normal dosage 10W viscosity HPMC in ordinary mortar in 0.15~0.2%, the water retention rate > 88% is no problem, but to 0.3 per thousand of the cellulose ether inferior the water retention rate may not be able to reach 88%, often more serious bleeding mortar. Therefore, the water retention rate is an important index to measure the advantages and disadvantages of HPMC. It is good or bad. As long as the mortar is added to the mortar, it will be clear at a glance.

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  • Advantages of building special hydroxypropyl methyl cellulose in architectural field

    Advantages of building special hydroxypropyl methyl cellulose in architectural field

    Advantages of building special hydroxypropyl methyl cellulose in architectural field Performance: 1. It is easy to mix with the dry powder formula. 2. It has the characteristics of cold water dispersion. 3, the solid particles are effectively suspended to make the mixture more slippery and homogeneous. Mixed: 1. The dry mix formula containing the special hydroxypropyl methyl cellulose of the building can be easily mixed with water. 2, obtain the required consistency quickly. 3, the dissolution of cellulose ether is faster and no mass. Construction: 1, improve the lubricity and plasticity to enhance the machinability so that the product construction is more convenient and quick. 2, enhance the water retention characteristic and prolong the working time. 3, it is helpful to prevent the drooping of mortar, mortar and tile. Lengthen the cooling time and improve the working efficiency. 4, improve the bonding strength of the ceramic tile adhesive. 5. Strengthen the crack resistance and crack strength of the mortar and plate filling agent. 6, improve the air content in the mortar, and greatly reduce the possibility of cracking. 7, it can enhance the anti drooping of the ceramic tile adhesive.

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  • Basic properties of hydroxypropyl methyl cellulose in the admixtures of dry mixed mortar

    Basic properties of hydroxypropyl methyl cellulose in the admixtures of dry mixed mortar

    In the dry mixed mortar, the cost of material is more than 40% in the dry mixed mortar, which has a key effect on the improvement of the performance of the building dry mixed mortar. Most of the admixtures in the domestic market are supplied by foreign manufacturers, and the reference amount of the products is also provided by the suppliers. As a result, the cost of dry mixed mortar products is high, and the general masonry and plastering mortar of large scale are difficult to be popularized. The high-end market products are controlled by foreign companies. Dry mixed mortar producers have low profits and poor price bearing capacity. The application of additives is lack of systematic and targeted research and blindly follow foreign formulations. Here, what we share is what is the role of hydroxypropyl methyl cellulose in the commonly used admixtures of dry mixed mortar? . Hydroxypropyl methyl cellulose is in recent years, the rapid increase in the amount of yield of cellulose varieties, hydroxypropyl methyl cellulose is made of refined cotton in alkali treated with propylene oxide and methyl chloride as etherifying agent, non-ionic cellulose ether is made through a series of reactions. The degree of substitution is generally 1.2~2.0. Its properties are different from the proportion of methoxy content and hydroxypropyl content. The properties of hydroxypropyl methylcellulose are as follows: 1. Hydroxypropyl methyl cellulose is easy to dissolve in cold water, and it will be difficult to dissolve hot water. But the gelation temperature in hot water is obviously higher than that of methyl cellulose. The dissolution of water in cold water is also much better than that of methyl cellulose. Two. The viscosity of hydroxypropyl methyl cellulose is related to the size of the molecular weight, and the viscosity of the HPMC is high. The temperature also affects the viscosity, the temperature and the viscosity. But the effect of high viscosity at high temperature is lower than that of methyl cellulose. The storage of the solution at room temperature is stable. Three. The water retention of hydroxypropyl methyl cellulose depends on its addition and viscosity, and the water retention rate under the same dosage is higher than that of methyl cellulose. Four, hydroxypropyl methyl cellulose has stability to acid and alkali, and its aqueous solution is very stable in the range of pH=2~12. Caustic soda and lime water has little effect on the performance, but can accelerate the dissolution of alkali, and slightly increase of viscosity. Hydroxypropyl methyl cellulose has stability to general salt, but the viscosity of HPMC is higher when the concentration of salt solution is high. Five, hydroxypropyl methyl cellulose can be mixed with water-soluble polymer to become a homogeneous and higher viscosity solution. Such as polyvinyl alcohol, starch ether, plant gum and so on. Six, hydroxypropyl methyl cellulose has better resistance to enzyme than methyl cellulose, and the possibility of enzyme degradation in solution is lower than that of methyl cellulose. Seven. The adhesion of hydroxypropyl methyl cellulose to mortar construction is higher than that of methyl cellulose.

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  • Application of hydroxypropyl methyl cellulose in PVC industry

    Application of hydroxypropyl methyl cellulose in PVC industry

    Hydroxypropyl methyl cellulose (HPMC) is one of the main dispersants in polyvinyl chloride (PVC) industry. The suspension polymerization of vinyl chloride, it can reduce the interfacial tension between VCM and water, help vinyl chloride monomer (VCM) uniformly and stably dispersed in the water; prevent VCM droplets in the polymerization process and polymerization process in the late stage; prevent the coalescence between polymer particles. In the suspension polymerization system, it plays a dual role of dispersing and protecting stability.

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  • The effect of improper use of hydroxypropyl methyl cellulose

    The effect of improper use of hydroxypropyl methyl cellulose

    By using the method of professional chemical products related to the first, each job must cause the operator"s attention and attention, because this is the key to effective decision-making of each construction project successfully completed so that if you do not use the normative method made it, it is very likely to seriously affect the safe use of the product. For example, the field is very hot with hydroxypropyl methyl cellulose, in the following we understand together. The water retention of hydroxypropyl methyl cellulose depends on its addition, viscosity, particle fineness and dissolution rate. Large amount of addition, small fineness, large viscosity, the water retention rate is high. The addition amount has the greatest influence on the water retention rate, and the viscosity is not proportional to the water retention rate. The dissolution rate mainly depends on the surface modification of cellulose particles and the fineness of the particles. The water retention rate of methyl cellulose and hydroxypropyl methyl cellulose is higher among the above several cellulose ethers. Methyl cellulose is soluble in cold water, and it is difficult to dissolve hot water, and its aqueous solution is very stable within the range of pH=3~12. It has good compatibility with starch, guar gum and many surfactants. Gelation occurs when the temperature reaches the gelation temperature. Above, we must give every operator"s attention and attention to the correct use of hydroxypropyl methyl cellulose, so as to better ensure the considerable use of this chemical product.

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  • How to determine the quality of hydroxypropyl methyl cellulose (HPMC) by water retention?

    How to determine the quality of hydroxypropyl methyl cellulose (HPMC) by water retention?

    How to determine the quality of hydroxypropyl methyl cellulose (HPMC) by water retention? The water retention of cellulose ether at high temperature is an important index to distinguish the quality of cellulose ether. Factors such as air temperature, humidity and wind pressure will affect the volatilization rate of moisture in cement mortar and gypsum based products. So in different seasons, there are some differences in the effect of adding hydroxypropyl methyl cellulose for the same amount of water. In the concrete construction, the addition of hydroxypropyl methyl cellulose can be added to adjust the water retention effect of the slurry. A good series of hydroxypropyl methyl cellulose products can effectively solve the problem of water retention at high temperature. High quality hydroxypropyl methyl cellulose is needed to improve the water retention of the slurry in high temperature season, especially in hot and dry areas and thin layer construction on the positive side. High quality hydroxypropyl methyl cellulose, its uniformity is very good, the methoxy and hydroxypropoxy group along the cellulose chain distribution, it can improve the hydroxyl and ether bond on the oxygen atom and water molecules capable of forming hydrogen bonds, free water into a combination of water, so as to effectively control the water evaporation in high temperature weather the reach high water retention. High quality cellulose can be uniformly and effectively dispersed in cement mortar and gypsum products, and wrapped all the solid particles, and the formation of a layer of membrane wetting, medium water gradually released in quite a long time, hydration and inorganic cementitious materials, so as to ensure the material bonding strength and compressive strength. So, in the construction of high temperature in summer, in order to achieve the effect of water conservation, according to the formula of hydroxypropyl methyl cellulose products, adding enough high-quality otherwise, there will be excessive drying caused by water is not enough, strength reduction, cracking, hollowing and loss and other quality problems, but also increase the difficulty of construction workers. As the temperature decreases, the amount of hydroxy propyl methylcellulose can be gradually reduced and the same water retention effect can be achieved.

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  • Dissolution and determination of hydroxypropyl methyl cellulose HPMC

    Dissolution and determination of hydroxypropyl methyl cellulose HPMC

    Dissolution and determination of hydroxypropyl methyl cellulose HPMC Determination method Method name: hydroxypropyl methyl cellulose - hydroxypropyl - Determination of hydroxypropyl - -- Determination of hydroxypropyl Application scope: this method uses hydroxypropyl group determination method to determine hydroxypropyl content in HPMC. This method is suitable for hydroxypropyl methyl cellulose. Method: the content of hydroxypropyl group was calculated by hydroxypropyl group. Reagent: 1.30% (g/g) three chromium oxide hydroxide solution 2. 3. phenolphthalein solution 4. sodium bicarbonate 5. sulfuric acid 6. potassium iodide 7. sodium thiosulfate titration solution (0.02mol/L) 8. starch indicator solution Instrument and equipment: Sample preparation: 1. sodium hydroxide titrant (0.02mol/L) Preparation: the clarified sodium hydroxide saturated solution 5.6mL, adding new boiling water to make 1000mL. In the benchmark calibration: take phthalate 105 DEG C dried to constant weight of two potassium hydrogen phthalate is about 6G, precision said, cold water 50mL, add new boiling shake, to minimize dissolution; with phenolphthalein indicator drops 2 drops, with the droplets, close to the end point, should make the adjacent benzene two formic acid potassium hydrogen dissolved completely, titration solution to pink. The sodium hydroxide titrant per 1mL (1mol/L) is equivalent to 20.42mg potassium hydrogen phthalate two. According to the consumption of this liquid and the amount of potassium hydrogen from phthalic acid two, the concentration of the liquid is calculated. The quantitative dilution is 5 times, and the concentration is 0.02mol/L. Storage: in polyethylene plastic bottle, sealed and stored. There are 2 holes in the stopper, 1 glass tubes are inserted into the holes, 1 pipes are connected to Soda Lime pipes, and 1 pipes are used for sucking out the liquid. 2. phenolphthalein extraction of phenolphthalein 1g, 100mL dissolved with ethanol 3. sodium thiosulfate titration solution (0.02mol/L): prepare sodium thiosulfate 26G and anhydrous sodium carbonate 0.20g, add the amount of cold water that is newly boiled, dissolve it into 1000mL, shake it up, and filter it after 1 months. In the benchmark calibration: potassium dichromate drying at 120 deg.c constant weight about 0.15g, precision said, the iodine bottle, add 50mL water to dissolve, add the potassium 2.0g, gently shake to dissolve, add 40mL of dilute sulfuric acid, then plug; for 10 minutes in the dark, water dilution of 250mL with the droplets to near the end point, and the starch indicating liquid 3mL, continue the titration to disappear blue and light green, and the titration correction by blank test results. Sodium thiosulfate per 1mL (0.1mol/L) is equivalent to 4.903g potassium dichromate. According to the consumption of the liquid and the dosage of potassium dichromate, the concentration of the liquid is calculated, that is, the solution is obtained. The quantitative dilution is 5 times, and the concentration is 0.02mol/L. At room temperature above 25 degrees C, the reaction solution and the diluted water should be cooled to about 20 degrees C. 4., starch indicator solution takes soluble starch 0.5g and water 5mL to mix. Then slowly pour into 100mL boiling water. Add stirring with stirring, continue boiling for 2 minutes, let cool and pour out the supernatant. This liquid should be used as a new system. Operation steps: take this product 0.1g, precision and set, set the distilled bottle D, add 30% (g/g) three cadmium chloride solution 10mL. In the steam generator B, the water is loaded into the joint to connect the distillation unit. B and D were immersed in oil bath (glycerol), so that the oil bath surface was consistent with the three cadmium chloride solution in the D bottle. The cooling water was opened, and the nitrogen flow was controlled when necessary, and the flow rate was 1 bubbles per second. Oil bath in 30 minutes to heat up to 155 degrees C, and to maintain the temperature to collect distilled liquid 50mL, the condensation tube self fractionating column removed, rinsed with water, washing into the collected solution with phenolphthalein indicator titration with 3 drops of liquid, until the pH value is 6.9 ~ (7.1 meter). Write down the consumption volume of V1 (mL) and 0.5g plus sodium bicarbonate with dilute sulfuric acid 10mL, static to no longer produce carbon dioxide, add the potassium 1.0g, plug, shake, a dark place for 5 minutes, add starch indicating liquid 1mL, titrated with sodium thiosulfate solution (0.02mol/L) titration end point to note, volume V2 consumption (mL). In addition to the blank test, the volume Va and Vb (mL) of sodium hydroxide titrant (0.02mol/L) and sodium thiosulfate titrant (0.02mol/L) were recorded.

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  • Extraction of hydroxypropyl methyl cellulose

    Extraction of hydroxypropyl methyl cellulose

    Hydroxypropyl methyl cellulose is made from highly purified cotton cellulose as raw material and is specially etherated under alkaline conditions. The whole process is completed under automatic monitoring without any active components such as animal organs and oils. This product is nonionic cellulose ether with white powder and odorless odorless. The refined cotton cellulose was treated for 35-40 hours at a temperature of half an hour, and the cellulose was crushed and aged at 35 C, so that the average degree of polymerization of the alkali fiber was in the required range. The alkali fibers were put into the etherification kettle, and the epoxy propane and chloromethane were added in turn to etherification 5h at 50-80 degrees C, and the maximum pressure was about 1.8MPa. Then a proper amount of hydrochloric acid and oxalic acid washing materials are added to the hot water at 90 C to expand the volume. Dehydrate with a centrifuge. When the washing is neutral, when the water content in the material is less than 60%, the thermal air flow at 130 C is dried to less than 5%. Finally smashed over 20 mesh to screen the finished product.

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  • Product characteristics of hydroxypropyl methyl cellulose for construction

    Product characteristics of hydroxypropyl methyl cellulose for construction

    The properties of HPMC for building are: it can be dissolved in cold water, the highest concentration is only determined by viscosity, the solubility varies with viscosity, the lower viscosity, the greater the solubility. Salt resistance Building hydroxypropyl methyl cellulose is non-ionic cellulose ether, and not polyelectrolyte. Therefore, when metal salts or organic electrolytes exist, it is relatively stable in aqueous solution, but excessive addition of electrolytes can cause gel and precipitation. surface activity As the aqueous solution has the function of surface activity, it can be used as a colloid protector, emulsifier and dispersant. The construction of special hydroxypropyl methyl cellulose solution when heated to a certain temperature, opaque, gel formation, precipitation, but in the continuous cooling, then returned to the original solution, the temperature and the gel and precipitation mainly depends on their lubricant, suspending agent, emulsifier, protective colloid. Anti mildew It has good anti mildew ability, and has good viscosity stability in the long term storage. PH stability The viscosity of the hydroxy propyl methyl cellulose aqueous solution for building is almost unaffected by acid or alkali, and the pH value is more stable in the range of 3.0~11.0. Shape retention Because the highly concentrated aqueous solution of HPMC for building has special viscoelastic properties compared with other polymer aqueous solutions, and its addition has the ability to improve the shape invariability of extruded ceramic products. Water retention High viscosity building special hydroxypropyl methyl cellulose is hydrophilic and its aqueous solution, is a high performance water reducer. Other characteristic thickeners, film forming agents, adhesives, lubricants, suspending agents, protective colloids, emulsifiers and so on.

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  • What is the principle of etherification synthesis of hydroxypropyl methyl cellulose?

    What is the principle of etherification synthesis of hydroxypropyl methyl cellulose?

    Hydroxypropyl methyl cellulose as raw material to produce substrate grease, can achieve full of sugar utilization, improve the utilization rate of raw materials, reduce the residual amount of substrate in fermentation liquid, reduce the cost of wastewater treatment, the properties of hydroxypropyl methyl cellulose for batch, fed batch, and continuous fermentation process optimization, to avoid a a series of control problems of medium composition and dilution rate; but also conducive to the regulation of fermentation process. Hydroxypropyl methyl cellulose, cellulose materials, can be refined cotton, wood pulp can also be, in the process of alkaline or alkaline the crushing is very necessary, through the aggregation structure of mechanical grinding can damage the cellulose material, in order to reduce the crystallinity and degree of polymerization, increases the surface area, so as to improve the cellulose molecules of glucose ring based on three hydroxyl groups of chemical reaction reagent. Although the principle of etherification of hydroxypropyl methyl cellulose is not complex, but various environments such as caustic soda, raw material crushing, etherification, solvent recovery, centrifugation, washing and drying involve a lot of technical keys and rich knowledge. For different products, each environment has the most recent control conditions, such as temperature, time, pressure and flow control. The auxiliary equipment and control instrument are the favorable guarantee for the stability of the product quality and the reliability of the production system. The properties of hydroxypropyl methyl cellulose and other water-soluble ether can be used for similar, latex paint and water soluble resin coating composition as film-forming agent, thickener, emulsifier and stabilizer, the coating has good wear resistance, uniform coating and adhesion, and improved the stability of surface tension the pH and compatibility of metallic pigment. Hydroxypropyl methyl cellulose has good effect as a thickening agent for white water based polyvinyl acetate coatings. The degree of substitution of cellulose ether increased and the resistance to bacteria was also enhanced.

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  • Temperature of hydroxypropyl methyl cellulose gel

    Temperature of hydroxypropyl methyl cellulose gel

    Many users rarely focus on hydroxypropyl methyl cellulose gel temperature for this problem, now generally according to distinguish the viscosity of hydroxypropyl methyl cellulose, but for some special environment and special industries only reflect the viscosity of the products is not enough, the following brief introduction of hydroxypropyl methyl cellulose gel temperature. The content of methoxy is directly related to the etherification degree of cellulose ether. The content of methoxy is regulated by controlling the formula, reaction temperature and reaction time. At the same time, the degree of etherification affects the degree of substitution of hydroxyethyl or hydroxypropyl. As a result, the water retention of cellulose ether at high gel temperature is a little worse. This production process is to explore, so it is not the methoxy content is low, the price of cellulose ether is low, on the contrary, the price will be a little higher. The gel temperature is determined by methoxy, and the water retention is determined by hydroxypropyl group. There are only three groups that can be replaced on cellulose. Find your proper use of temperature, suitable water retention, and then determine the model of the cellulose. The gel temperature is a critical point for the application of cellulose ether. When the ambient temperature exceeds the gel temperature, the cellulose ether will precipitate from the water and lose the water retention. On the market of cellulose ether gel temperature, can meet the basic needs of mortar using environment (special environment, except) that engage in personal mortar application does not need to pay particular attention to the performance index of the gel temperature, of course, engage in cellulose ether production manufacturers, must consider the.

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  • Whether the mortar efflorescence phenomenon associated with hydroxypropyl methyl cellulose

    Whether the mortar efflorescence phenomenon associated with hydroxypropyl methyl cellulose

    Ordinary concrete as Portland, or in the air inside the wall of water, the silicate ion hydrolysis reaction, the hydroxyl and the metal ions generated with smaller solubility form hydroxide (chemically alkaline), when temperatures rise, evaporation, precipitation of hydrogen oxide from the wall, along with the gradual evaporation of water, hydroxide is be on the concrete surface, making the original decoration of the days and months multiplying, paint or paint is jacked up, no adhesion occurred, metope, white skin, fall off, a process called "fanjian". So, is not caused by efflorescence of hydroxypropyl methyl cellulose. There is such a phenomenon in the collected information: a customer do spray is in the concrete wall will appear efflorescence, efflorescence phenomenon does not occur in the fire brick wall, the Portland in the concrete wall with cement (alkali salt content) too much. By using the spray water evaporation caused by efflorescence. Not in the fire brick wall does not occur Portland efflorescence. So, there efflorescence and spraying Never mind. Terms of settlement First, the silicate content of the base concrete cement is reduced. Two, the use of anti alkali back coating the solution into stone blocking the capillary, water, Ca (OH) 2, salt and other substances can not invade, cut off the way the efflorescence phenomenon. Three, prevent water intrusion, not a large amount of sprinkler before construction. Governance efflorescence phenomenon Can be used on the market stone whiskering cleaning agent, the cleaning agent is a colorless translucent liquid made of non-ionic surface active agent and solvent, have a certain effect on the cleaning part of natural stone surface efflorescence. But before use, it is necessary to make a small sample to test the effect and decide whether or not to use it.

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  • Knowledge popularization of hydroxypropyl methyl cellulose (HPMC)

    Knowledge popularization of hydroxypropyl methyl cellulose (HPMC)

    Hydroxypropyl methyl cellulose (HPMC) is a nonionic cellulose ether made from a natural polymer material cellulose, which is made from a series of chemical processes. They are a tasteless, nontoxic white powder that swells in cold water into a clear or slightly cloudy colloidal solution. It has the characteristics of thickening, adhesion, dispersion, emulsification, membrane formation, suspension, adsorption, gel, surface activity, retention of water and protective colloid. Hydroxypropyl methyl cellulose and methyl cellulose can be applied in building materials, coating industry, synthetic resin, ceramic industry, medicine, food, textile, agriculture, daily chemical industry and so on. HPMC chemical equation: [C6H7O2 (OH) 3-m-n (OCH3) m (OCH2CH (OH) CH3) n]x Water conservation and principle of HPMC: Cellulose ether HPMC, in cement mortar and gypsum base slurry, mainly plays the role of water retention and thickening, which can effectively improve the adhesive force and sag resistance of the slurry. Factors such as air temperature, humidity and wind pressure will affect the volatilization rate of moisture in cement mortar and gypsum based products. So in different seasons, there are some differences in the water retention effect of the same amount of HPMC added to the product. In the concrete construction, the water retention effect of the slurry can be adjusted by adding or reducing the amount of HPMC. The water retention of methyl cellulose ether under high temperature is an important index to distinguish the quality of methyl cellulose ether. The excellent HPMC series products can effectively solve the problem of water retention at high temperature. In the high temperature season, especially in the hot and dry areas and the thin-layer construction on the positive side, high quality HPMC is needed to improve the water retention of the slurry. High quality HPMC, the uniformity is very good, the methoxy and hydroxypropoxy group along the cellulose chain can improve the uniform distribution of hydroxyl and ether bond on the oxygen atom and water molecules capable of forming hydrogen bonds, free water into a combination of water, water evaporation in order to effectively control the hot weather caused the reach of high water retention. High quality cellulose HPMC can be uniformly and effectively dispersed in cement mortar and gypsum products, and wrapped all the solid particles, and the formation of a layer of membrane wetting, medium water gradually released in quite a long time, hydration and inorganic cementitious materials, so as to ensure the material bonding strength and compressive strength. So, in the construction of high temperature in summer, in order to achieve the effect of water conservation should be in accordance with the formula adding enough high-quality HPMC products, otherwise, there will be excessive drying caused by water is not enough, strength reduction, cracking, hollowing and loss and other quality problems, but also increase the difficulty of construction workers. As the temperature decreases, the amount of HPMC can be reduced gradually and the same water retention effect can be achieved. The water retention of HPMC is affected by the following factors: 1 cellulose ether HPMC homogeneity The uniform distribution of HPMC, methoxy and hydroxypropyl group, with high water retention rate. 2 cellulose ether HPMC thermal gel temperature The temperature of the thermal gel is high and the water retention rate is high; on the contrary, the water retention rate is low. 5 cellulose ether HPMC viscosity When the viscosity of HPMC rises, the water retention rate increases, and when the viscosity reaches a certain degree, the increase of water retention rate tends to be slow. 4 cellulose ether HPMC addition The greater the amount of cellulose ether HPMC is, the higher the water retention rate is, the better the water retention effect is. In the range of 0.25-0.6%, the water holding rate increased with the increase of the amount of added water. When the amount of added water increased further, the water holding rate increased slowly.

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  • Hydroxypropyl methyl cellulose (HPMC) is divided into several kinds. What is the difference in its use?

    Hydroxypropyl methyl cellulose (HPMC) is divided into several kinds. What is the difference in its use?

    Hydroxypropyl methyl cellulose HPMC can be divided into instant and hot: The instant product is dispersed rapidly in cold water and disappears in water. The liquid has no viscosity at this time, because HPMC is only dispersed in water and does not really dissolve. For about 2 minutes, the viscosity of the liquid gradually increased, forming a transparent sticky colloid Hot products in cold water, hold together, can quickly in hot water, dispersion, disappear in hot water, when the temperature drops to a certain temperature, viscosity slowly, until the formation of transparent viscous gel. Use: Hot melt type can only be used in the putty and mortar in liquid, glue and paint, will appear Baotuan phenomenon, can not be used. Quick solution, a wide range of applications, in putty powder and mortar, as well as liquid glue and paint, can be used, no taboo.

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  • Hydroxypropyl methyl cellulose, do not understand this to lose

    Hydroxypropyl methyl cellulose, do not understand this to lose

    1. hydroxypropyl methyl cellulose HPMC is divided into quick solubility and slow solubility HPMC quick solubility with the letter S to make a suffix, such as 100000S to express 100000 viscosity of instant HPMC, in the process of production, for addition of two aldehyde treatment. HPMC slowly soluble type without any letter, such as 100000 is 100000 viscosity slowly soluble type HPMC. 2. band without S, different characteristics The instant HPMC is dispersed rapidly in cold water and disappeared in the water. At that time, the liquid has no viscosity, because HPMC is dispersed in water without real dissolution. After about two minutes, the viscosity of the liquid becomes larger and larger, forming transparent colloid colloid. Slowly soluble HPMC can disperse rapidly in cold water at 70 degrees or so. When the temperature drops to a certain temperature, the viscosity slowly appears until transparent colloid colloid is formed. 3. band without S, different use Slowly soluble HPMC can only be used in putty powder and mortar. In liquid glue and paint and washing products, it will be unused. Quick soluble HPMC, widely used in putty powder, mortar, liquid glue, paint, washing products can be used, no taboo.

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