Key Questions to Ask When Ordering Hydroxypropyl Methyl Cellulose (HPMC)

1. What is the main application of hydroxypropyl methylcellulose (HPMC)?

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——Answer: Hydroxypropyl methylcellulose is widely used in construction materials, coatings, synthetic resins, ceramics, medicine, food, textiles, agriculture, cosmetics, tobacco and other industries. Hydroxypropyl methylcellulose can be divided into construction grade, food grade and pharmaceutical grade according to its application. At present, most of the domestic products are 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 methylcellulose (HPMC), and what are the differences in their uses?

——Answer: HPMC can be divided into instant type and hot-dissolution type. Instant type products disperse quickly in cold water and disappear into 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 increases, forming a transparent viscous colloid. Hot-melt products, when met with cold water, can disperse quickly in hot water and disappear in hot water. When the temperature drops to a certain temperature, the viscosity will slowly appear until it forms a transparent viscous colloid. The hot-melt type can only be used in putty powder and mortar. In liquid glue and paint, there will be grouping phenomenon 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 liquid glue and paint, without any contraindications.

3. What are the dissolution methods of hydroxypropyl methylcellulose (HPMC)?

——Answer: Hot water dissolution method: Since HPMC does not dissolve in hot water, HPMC can be evenly dispersed in hot water at the initial stage, and then dissolve quickly when cooling. Two typical methods are described as follows:

1) Put the required amount of hot water into the container and heat it to about 70°C. The hydroxypropyl methylcellulose was gradually added under slow stirring, initially the HPMC floated on the surface of the water, and then gradually formed a slurry, which was cooled under stirring.

2), add 1/3 or 2/3 of the required amount of water into the container, and heat it to 70°C, disperse HPMC according to the method of 1), and prepare hot water slurry; then add the remaining amount of cold water to hot water slurry, the mixture was cooled after stirring.

Powder mixing method: mix HPMC powder with a large amount of other powdery substances, mix thoroughly with a mixer, and then add water to dissolve, then HPMC can be dissolved at this time without agglomeration, because there is only a little HPMC in every tiny corner Powder, will dissolve immediately when in contact with water. ——Putty powder and mortar manufacturers are using this method. [Hydroxypropyl methylcellulose (HPMC) is used as a thickener and water retention agent in putty powder mortar. ]

4. How to judge the quality of hydroxypropyl methylcellulose (HPMC) simply and intuitively?

——Answer: (1) Whiteness: Although whiteness cannot determine whether HPMC is easy to use, and if whitening agents are added during the production process, it will affect its quality. However, most of the good products have good whiteness. (2) Fineness: The fineness of HPMC generally has 80 mesh and 100 mesh, and 120 mesh is less. Most HPMC produced in Hebei is 80 mesh. The finer the fineness, generally speaking, the better. (3) Light transmittance: put hydroxypropyl methylcellulose (HPMC) into water to form a transparent colloid, and look at its light transmittance. The greater the light transmittance, the better, indicating that there are less insolubles in it. . The permeability of vertical reactors is generally good, and that of horizontal reactors is worse, but it does not mean that the quality of vertical reactors is better than that of horizontal reactors, and product quality is determined by many factors. (4) Specific gravity: The larger the specific gravity, the heavier the better. The specificity is large, generally because the content of hydroxypropyl group in it is high, and the content of hydroxypropyl group is high, the water retention is better.

5. What is the amount of hydroxypropyl methylcellulose (HPMC) in the putty powder?

——Answer: The amount of HPMC used in practical applications varies depending on the climate, temperature, quality of local ash calcium, formula of putty powder and "quality required by customers". Generally speaking, between 4 kg and 5 kg. For example: most of the putty powder in Beijing is 5 kg; most of the putty powder in Guizhou is 5 kg in summer and 4.5 kg in winter; the amount of putty in Yunnan is relatively small, generally 3 kg to 4 kg, etc.

6. What is the appropriate viscosity of hydroxypropyl methylcellulose (HPMC)?

——Answer: Generally, 100,000 yuan is enough for putty powder, and the requirements for mortar are higher, and 150,000 yuan is required for easy use. Moreover, the most important function of HPMC is water retention, followed by thickening. In the putty powder, as long as the water retention is good and the viscosity is low (70,000-80,000), it is also possible. Of course, the higher the viscosity, the better the relative water retention. When the viscosity exceeds 100,000, the viscosity will affect the water retention. Not much anymore.

7. What are the main technical indicators of hydroxypropyl methylcellulose (HPMC)?

——Answer: Hydroxypropyl content and viscosity, most users are concerned about these two indicators. Those with high hydroxypropyl content generally have better water retention. The one with high viscosity has better water retention, relatively (not absolutely), and the one with high viscosity is better used in cement mortar.

8. What are the main raw materials of hydroxypropyl methylcellulose (HPMC)?

—— Answer: The main raw materials of hydroxypropyl methylcellulose (HPMC): refined cotton, methyl chloride, propylene oxide, and other raw materials, caustic soda, acid, toluene, isopropanol, etc.

9. What is the main function of the application of HPMC in putty powder, and does it happen chemically?

——Answer: In the putty powder, HPMC plays three roles of thickening, water retention and construction. Thickening: Cellulose can be thickened to suspend and keep the solution uniform up and down, and resist sagging. Water retention: make the putty powder dry slowly, and assist the ash calcium to react under the action of water. Construction: Cellulose has a lubricating effect, which can make the putty powder have good construction. HPMC does not participate in any chemical reactions, but only plays an auxiliary role. Adding water to the putty powder and putting it on the wall is a chemical reaction, because new substances are formed. If you remove the putty powder on the wall from the wall, grind it into powder, and use it again, it will not work because new substances (calcium carbonate) have been formed. ) too. The main components of ash calcium powder are: a mixture of Ca(OH)2, CaO and a small amount of CaCO3, CaO+H2O=Ca(OH)2—Ca(OH)2+CO2=CaCO3↓+H2O Ash calcium is in water and air Under the action of CO2, calcium carbonate is generated, while HPMC only retains water, assisting 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-ionic?

——Answer: In layman's terms, non-ions are substances that do not ionize in water. Ionization refers to the process in which an electrolyte is dissociated into charged ions that can move freely in a specific solvent (such as water, alcohol). For example, sodium chloride (NaCl), the salt we eat every day, dissolves in water and ionizes to produce freely movable sodium ions (Na+) that are positively charged and chloride ions (Cl) that are negatively charged. That is to say, when HPMC is placed in water, it will not dissociate into charged ions, but exist in the form of molecules.

11. What is the gel temperature of hydroxypropyl methylcellulose related to?

——Answer: The gel temperature of HPMC is related to its methoxy content. The lower the methoxy content↓, the higher the gel temperature↑.

12. Is there any relationship between the drop of putty powder and HPMC?

——Answer: The powder loss of putty powder is mainly related to the quality of ash calcium, and has little to do with HPMC. The low calcium content of gray calcium and the improper ratio of CaO and Ca(OH)2 in gray calcium will cause powder loss. If it has something to do with HPMC, then if HPMC has poor water retention, it will also cause powder loss. For specific reasons, please refer to question 9.

13. What is the difference between the cold-water instant type and the hot-soluble type of hydroxypropyl methylcellulose in the production process?

——Answer: The cold water instant type of HPMC is surface-treated with glyoxal. It disperses quickly in cold water, but it does not really dissolve. It only dissolves when the viscosity increases. Hot melt types are not surface treated with glyoxal. If the amount of glyoxal is large, the dispersion will be fast, but the viscosity will increase slowly, and if the amount is small, the opposite will be true.

14. What is the smell of hydroxypropyl methylcellulose (HPMC)?

——Answer: The HPMC produced by the solvent method uses toluene and isopropanol as solvents. If the washing is not very good, there will be some residual smell.

15. How to choose a suitable hydroxypropyl methylcellulose (HPMC) for different purposes?

——Answer: The application of putty powder: the requirements are relatively low, and the viscosity is 100,000, which is enough. The important thing is to keep water well. Application of mortar: higher requirements, high viscosity, 150,000 is better. Application of glue: instant products with high viscosity are required.

16. What is the alias of hydroxypropyl methylcellulose?

——Answer: Hydroxypropyl Methyl Cellulose, English: Hydroxypropyl Methyl Cellulose Abbreviation: HPMC or MHPC Alias: Hypromellose; Cellulose Hydroxypropyl Methyl Ether; Hypromellose, Cellulose, 2-hydroxypropylmethyl Cellulose ether. Cellulose hydroxypropyl methyl ether Hyprolose.

17. The application of HPMC in putty powder, what is the reason for the bubbles in the putty powder?

——Answer: In the putty powder, HPMC plays three roles of thickening, water retention and construction. Do not participate in any reactions. Reasons for bubbles: 1. Put too much water. 2. The bottom layer is not dry, just scrape another layer on top, and it is easy to foam.

18. What is the formula of putty powder for interior and exterior walls?

——Answer: Putty powder for interior walls: heavy calcium 800KG gray calcium 150KG (starch ether, pure green, pentagentite, citric acid, polyacrylamide, etc. can be added appropriately)

External 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?

——Answer: MC is methyl cellulose, which is made of cellulose ether by treating refined cotton with alkali, using methane chloride as etherification agent, and going through a series of reactions. Generally, the degree of substitution is 1.6~2.0, and the solubility is also different with different degrees of substitution. It belongs to non-ionic cellulose ether.

(1) The water retention of methyl cellulose depends on its addition amount, viscosity, particle fineness and dissolution rate. Generally, if the addition amount is large, the fineness is small, and the viscosity is large, the water retention rate is high. Among them, the amount of addition has the greatest impact on the water retention rate, and the level of viscosity is not directly proportional to the level of water retention rate. The dissolution rate mainly depends on the degree of surface modification of cellulose particles and particle fineness. Among the above cellulose ethers, methyl cellulose and hydroxypropyl methyl cellulose have higher water retention rates.

(2) Methylcellulose is soluble in cold water, and it will be difficult to dissolve in hot water. Its aqueous solution is very stable in the range of pH=3~12. It has good compatibility with starch, guar gum, etc. and many surfactants. When the temperature reaches the gelation temperature, gelation occurs.

If you want to learn more, please visit our website Hydroxypropyl Methyl Cellulose (HPMC).

(3) Changes in 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°C, the water retention of methyl cellulose will be significantly reduced, seriously affecting the construction of the mortar.

(4) Methyl cellulose has a significant effect on the construction and adhesion of mortar. The "adhesion" here refers to the adhesive force felt between the worker's applicator tool and the wall substrate, that is, the shear resistance of the mortar. The adhesiveness is high, the shear resistance of the mortar is large, and the strength required by the workers in the process of use is also large, and the construction performance of the mortar is poor. Methyl cellulose adhesion is at a moderate level in cellulose ether products.

HPMC is hydroxypropyl methylcellulose, which is a non-ionic cellulose mixed ether made from refined cotton after alkalization, using propylene oxide and methyl chloride as etherification agents, and through a series of reactions. The degree of substitution is generally 1.2~2.0. Its properties are different due to the different ratios of methoxyl content and hydroxypropyl content.

(1) Hydroxypropyl methylcellulose is easily soluble in cold water, and it will encounter difficulties in dissolving in hot water. But its gelation temperature in hot water is significantly higher than that of methyl cellulose. The solubility in cold water is also greatly improved compared with methyl cellulose.

(2) Hydroxypropyl methylcellulose 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 little effect on its performance, but alkali can speed up its dissolution and increase its viscosity. Hydroxypropyl methylcellulose is stable to common salts, but when the concentration of salt solution is high, the viscosity of hydroxypropyl methylcellulose solution tends to increase.

(3) Hydroxypropyl methylcellulose can be mixed with water-soluble polymer compounds to form a uniform and higher viscosity solution. Such as polyvinyl alcohol, starch ether, vegetable gum, etc.

(4) The adhesion of hydroxypropyl methylcellulose to mortar construction is higher than that of methylcellulose.

(5) Hydroxypropyl methylcellulose has better enzyme resistance than methylcellulose, and its solution is less likely to be degraded by enzymes than methylcellulose.

20. What should be paid attention to in the actual application of the relationship between the viscosity and temperature of hydroxypropyl methylcellulose?

——Answer: The viscosity of HPMC is inversely proportional to the temperature, that is to say, the viscosity increases as the temperature decreases. The viscosity of a product we usually refer to refers to the test result of its 2% aqueous solution at a temperature of 20 degrees Celsius.

In practical applications, it should be noted that in areas with large temperature differences between summer and winter, it is recommended to use a relatively low viscosity in winter, which is more conducive to construction. Otherwise, when the temperature is low, the viscosity of the cellulose will increase, and the hand feel will be heavy when scraping.

Medium viscosity: - mainly used for putty

Reason: good water retention

High viscosity: - Mainly used for polystyrene particle thermal insulation mortar rubber powder and vitrified microbead thermal insulation mortar.

Reason: The viscosity is high, the mortar is not easy to fall off, sag, and the construction is improved.

But generally speaking, the higher the viscosity, the better the water retention. Therefore, considering the cost, many dry powder mortar factories replace medium and low viscosity cellulose (-) with medium-viscosity cellulose (-) to reduce the amount of addition.

SDSs issued in Europe are in compliance with all applicable European legislation requirements, including REACH requirements as interpreted by the European Commission. 

Due to practical challenges of implementing the SDS changes required by REACH before the start of the Registration process, the European Commission supported the CEFIC position with respect to the following key points:

• The only requirements that could reasonably be implemented by June 1, were mainly format changes. (These include reversing the content of Sections 2 and 3, inserting the address of the individual responsible for creating the SDS in Section 1, and for substances not classified as dangerous, adding the reason for indicating the substance in Section 3).
• SDSs that do not need to be revised for reasons other than the above format changes can stay in the pre-REACH format and are considered to be still in compliance because their content is correct. For newly created SDSs, and for revised SDSs, the format changes must be implemented.
• All changes required by REACH as described in articles 31 and Annex II of the Regulation should be implemented before Dec 1, , which coincides with the first deadline for registration. Until that date, the SDSs circulating in Europe will be in 2 different formats.

The manufacturer has implemented the above recommendations of the European Commission. On this basis, our SDSs comply with the REACH requirements as currently defined and interpreted by the European Commission. 

The apparent viscosity of an aqueous solution of a METHOCEL cellulose ether is proportional to the molecular weight or chain length of the specific METHOCEL product used. Commercial designations of METHOCEL products are based on viscosity values determined in water at 20°C, with a concentration of 2% METHOCEL. The measurement methods used are described in the current ASTM monographs D and D. The correlation between the number average molecular weight (Mn) and the commercial viscosity designation for METHOCEL A cellulose ethers is shown in the figure below.

The table below provides further information regarding the correlation of number average molecular weight with the commercial viscosity designation. Intrinsic viscosity is the limiting quotient of the specific viscosity divided by the concentration as infinite dilution is approached (as the concentration approaches zero). The number average molecular weight (Mn) is calculated from the limiting osmotic pressure of the solvent as the concentration of the solute approaches zero. The average molecular weight (Mw) will be 3 to 10 times the Mn.

Viscosity of Methylcellulose of Various Molecular Weights

 

The full nomenclature is described as follows. METHOCEL™ is a trademark of IFF for a line of cellulose ether products. An initial letter identifies the type of cellulose ether. "A" identifies methylcellulose products. "E", "F", and "K" identify different hydroxypropyl methylcellulose (USP hypromellose) products. The number that follows identifies the viscosity in millipascal-seconds (mPa.s) of that product measured at 2% concentration in water at 20°C. In designating viscosity, the letter "C" is frequently used to represent 100 and the letter "M" is used to represent 1,000.  In the USP this is referred to as the labeled viscosity.  It is also given on the IFF sales specification as the nominal viscosity.

Several different suffixes are also used to identify special products. "P" is sometimes used to identify METHOCEL™ Premium grade products; Premium grade products are compliant with the United States Pharmacopeia (USP), European Pharmacopeia (PhEur), and the Japanese Pharmacopeia (JP).  "LV" refers to special Low Viscosity products, "CR" denotes a Premium, Controlled Release grade.

Example A: METHOCEL™ A4C Premium is the designation for a Premium grade methylcellulose product having a viscosity of 400 mPa s.

The METHOCEL cellulose ether packages are filled according to the legal requirement for size of container and the weight contained.  The requirement is listed in the NIST Handbook for Weights and Measures, 4th edition, Appendix A, Table 2.5.

Bags:  According to the NIST handbook, packages labeled by weight more than 42.40 lb to 54.40 lb allow for +/- 0.5 lb weight variance.  This equates to a range of 49.5 - 50.5 lbs.
 
25kg  (55.1 lb) Drums:  According to the NIST handbook, packages labeled by weight more than 24.67 kg or 54.40 lb allow for 2% weight variance.  For 55.1 lb (25 kg) drums, this equates to a range of +/- 1.1 lbs resulting in a range of 54.0 to 56.2 lbs.   
 
50kg (110.2 lb) Drums:  According to the NIST handbook, packages labeled by weight more than 24.67 kg or 54.40 lb allow for 2% weight variance.  For 110.2 lb (50kg) drums, this equates to a range of +/- 2.2 lbs resulting in a range of 108.0 to 112.4 lbs.

General properties common to the whole family of METHOCEL cellulose ether products are listed below. Individual METHOCEL products exhibit these properties to varying degrees and may have additional properties that are desirable for specific applications.

Water solubility - METHOCEL cellulose ethers dissolve in water with no sharp solubility limit.  Surface-treated and granular METHOCEL products can be added directly to aqueous systems.  This feature provides exceptional handling flexibility and control of solubilization rate.  Although untreated METHOCEL powders are soluble in cold water, they must first be thoroughly dispersed in the water to prevent lumping.  The maximum concentration is limited only by solution viscosity.

Organic solubility - Certain types and grades of METHOCEL cellulose ethers are also soluble in binary organic and organic solvent/water systems, providing a unique combination of organic solubility and water solubility.

No ionic charge - METHOCEL cellulose ethers are nonionic and will not complex with metallic salts or other ionic species to form insoluble precipitates.

Thermal gelation - Aqueous solutions of METHOCEL products gel when heated above a particular temperature, providing controllable quick-set properties.  Unlike gels formed by protein thickeners, the gels go back into solution upon cooling.

Surface activity - METHOCEL cellulose ether products act as surfactants in aqueous solutions to provide emulsification, protective colloid action, and phase stabilization. Surface tensions range from 42 to 64 mN/m. The surface tension of water is 72 mN/m; a typical surfactant has a surface tension of 30 mN/m.

Metabolic inertness - Used as food and drug additives, METHOCEL products do not add calories to the diet.

Enzyme resistance - Enzyme-resistant METHOCEL products provide excellent viscosity stability during long-term storage.

Low taste and odor - METHOCEL cellulose ethers have excellent (low) flavor and aroma properties, which is important in food and pharmaceutical applications.

pH stability - METHOCEL cellulose ethers are stable over a pH range of 3 to 11.

Water retention - METHOCEL cellulose ethers are highly efficient water-retention agents. This is valuable in food products, ceramics, coatings on adsorbent construction substrates, and many other applications.

Thickening - METHOCEL cellulose ethers thicken both aqueous and nonaqueous systems. The viscosity is related to the molecular weight, chemical type, and concentration of the specific METHOCEL product.

Film formation - METHOCEL products form clear, tough, flexible films that are excellent barriers to oils and greases. In food applications, this property is often used to retain moisture and prevent oil absorption during cooking.

Binding - METHOCEL cellulose ethers are used as high-performance binders for pigments, paper, structured foods, pharmaceutical products, and ceramics.

Lubrication - METHOCEL products are used to reduce friction in rubber, cement, and ceramic extrusions. They are also used to improve pumpability of concrete and spray plasters, such as stucco, and in food applications as lubricity aids in extrusion and other forming processes.

Suspending - METHOCEL products are used to control settling of solid particles, for example, herbs and spices in salad dressings, solids in ceramic slips, and antacid suspensions.

Protective colloidal action - METHOCEL products are used to prevent droplets and particles from coalescing or agglomerating.

Emulsification - METHOCEL cellulose ethers stabilize emulsions by reducing surface and interfacial tensions and by thickening the aqueous phase.

METHOCEL cellulose ether products are water-soluble polymers derived from cellulose, the most abundant polymer in nature.  Hydroxypropyl methylcellulose (HPMC) and methylcellulose (MC) are manufactured from highly purified cellulose which is further modified to obtain the desired properties. They are inert, high purity powders with no caloric value, and are virtually colorless, odorless and tasteless.

Premium and Food Grades of METHOCEL HPMC and MC products are recognized as acceptable for use in food by the food regulatory bodies of almost every country. Hydroxypropyl methylcellulose and methylcellulose are listed in the current U.S. CFR, the Food Chemicals Codex and the International Codex Alimentarius. METHOCEL Premium products are also included in the current U.S. Pharmacopoeia, European Pharmacopoeia and Japanese Pharmacopoeia.

Additionally, methylcellulose is Generally Recognized as Safe (GRAS) by the U.S. FDA. All METHOCEL HPMC Food Grade Products are considered by the FDA to be GRAS per GRAS Notification GRN .

METHOCEL Premium and Food Grade products are certified as Kosher and pareve for year-round and Passover use by the Union of Orthodox Congregations of America and they all conform to HALAL requirements.

For more information, please visit Hydroxy Ethyl Cellulose.