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Product Introduction
Natural cellulose is the most widely distributed and abundant polysaccharide in nature, with a very rich source. Current cellulose modification technologies mainly focus on etherification and esterification. Carboxymethylation is a type of etherification technology. After carboxymethylation, cellulose becomes Carboxymethyl Cellulose (CMC), and its aqueous solution has thickening, film-forming, adhesive, moisture retention, colloid protection, emulsifying, and suspending properties. It is widely used in industries such as petroleum, food, pharmaceuticals, textiles, and paper, making it one of the most important cellulose ethers.
Production Process
The production of Sodium Carboxymethyl Cellulose (CMC) uses chloroacetic acid and refined cotton as the main raw materials. The production process involves dissolving in ethanol medium, alkalizing, washing, drying, and other steps to obtain Sodium Carboxymethyl Cellulose.
The production equipment mainly consists of five parts: acid-alkali preparation, washing, drying, residual liquid distillation.
The process flow is briefly described as follows:
- Acid-Alkali Preparation Section
Add 95% ethanol and stir in solid chloroacetic acid to prepare a 57% solution. Add the weighed refined cotton and metered alkali to the alkalization machine simultaneously, allowing it to penetrate the cellulose evenly. Alkalization takes 60 minutes with an excess of alkali, and the pH is 12. After alkalization, evenly add the metered 57% chloroacetic acid to the alkalization machine. Alkalization lasts 60 minutes. Cellulose is alkalized to alkali cellulose:
Cell-(OH)(3)+xNaOH→Cell-(OH)(3)-x(O-Na(+))(x)+xH(2)O
- Etherification Process
The alkalized material is discharged into the etherification machine, where it reacts at an elevated temperature for about 90 minutes. After the reaction is complete, cool it down to 40-45 degrees and discharge it into the washing tank for cleaning. Alkali cellulose and sodium chloroacetate are converted to:
Cell-(OH)(3)-x(O-Na(+))(x)+nClCH(2)COONa→Cell-(OH)(3)-x(ONa)(x)-n(OCH(2)COO-Na(+)) n + nNaCl
- The prepared ethanol is injected into the washing tank, then the material from the etherification machine is discharged into the washing tank. Measure the pH value, then add hydrochloric acid to neutralize to pH=7. After stirring for a certain time (20 minutes), pump it into a centrifuge to separate the solid and liquid. The solid cellulose moves to the next stage for alcohol recovery, while the liquid part enters the waste alcohol tank and is pumped into a distillation tower for ethanol purification. The distillation process produces ethanol-containing waste gas, and the residue is a liquid containing NaCl and a small amount of carboxyethanol sodium, which is further distilled to crystallize solid NaCl. The distilled liquid phase enters the Mechanical Vapor Recompression (MVR) evaporator. The NaCl containing a small amount of moisture is separated by centrifugation, with the NaCl solid sold to other production enterprises, and the centrifuge liquid re-enters the three-effect evaporation system. After neutralization and washing:
Cell-(OH)(3)-x(ONa)(x)-n(OCH(2)COO-Na(+)) n+(x-n)CH(3)COOH→Cell-(OH)(3)-n(OCH(2)COO-Na(+)) n+(x-n)CH(3)COONa
- Drying Section
The cellulose solid material coming out of the centrifuge, with a moisture content of 45%, enters the gas stripping machine, where vacuum is applied, drying, and heating recover the alcohol. The drying process produces organized ethanol-containing waste gas emissions. The cellulose solid material enters the drying and crushing process, resulting in the final product. The drying process produces organized ethanol-containing waste gas emissions. The crushing process waste gas is collected by a pulse dust collector, and the product dust filtered by the pulse dust collector is discharged through the exhaust pipe. The dust collected by the dust collector is added to the product and sold.
The produced products include food-grade Sodium Carboxymethyl Cellulose, oilfield-grade Sodium Carboxymethyl Cellulose, paper-grade Sodium Carboxymethyl Cellulose, cosmetic and toothpaste-grade Sodium Carboxymethyl Cellulose, pharmaceutical-grade Sodium Carboxymethyl Cellulose, and other types of Sodium Carboxymethyl Cellulose requiring higher viscosity. Therefore, most use refined cotton as the raw material, with a small portion using wood pulp as the raw material. Technologically, both refined cotton and wood pulp have a moisture content of 8%, and all participate in the reaction. Except for product viscosity, there is no difference.
Effects and Functions
CMC can serve as an adhesive, thickening agent, suspending agent, emulsifier, dispersant, stabilizer, and sizing agent.
Applications
Carboxymethyl Cellulose (CMC) is a non-toxic, odorless, white, fluffy powder with stable performance and easy solubility in water. Its aqueous solution is a neutral or alkaline, transparent, viscous liquid that can dissolve in other water-soluble gels and resins but is insoluble in organic solvents like ethanol. CMC is widely used as an adhesive, thickener, suspending agent, emulsifier, dispersant, stabilizer, and sizing agent.
Carboxymethyl Cellulose (CMC) is the most produced, widely used, and convenient cellulose ether product, commonly referred to as industrial MSG.
- In Oil and Gas Drilling and Well Construction
- CMC-containing mud can form a thin yet strong filter cake on well walls, reducing permeability and water loss.
- Adding CMC to the mud reduces the initial cutting force on drilling equipment, facilitates gas release, and quickly settles debris in the mud pit.
- Like other suspensions and dispersions, drilling muds have a limited presence period; adding CMC stabilizes and extends this period.
- CMC-containing mud is less affected by mold, reducing the need to maintain a high pH or use preservatives.
- CMC can treat drilling mud washing fluids to resist contamination by various soluble salts.
- CMC-containing mud maintains good stability, even at temperatures above 150°C, reducing water loss.
High-viscosity, high-substitution CMC is suitable for low-density muds, while low-viscosity, high-substitution CMC is suitable for high-density muds. CMC selection should be based on the type of mud and specific conditions like region and well depth.
- In Textile and Dyeing IndustriesCMC is used as a sizing agent for cotton, silk, wool, synthetic fibers, and blended fabrics.
- In Paper IndustryCMC can act as a surface smoother and sizing agent. Adding 0.1% to 0.3% CMC to the paper pulp enhances tensile strength by 40% to 50%, increases burst strength by 50%, and improves the beating resistance by 4 to 5 times.
- In Household and Industrial Products
- CMC in synthetic detergents acts as a dirt adsorbent.
- In daily chemicals like toothpaste, CMC's glycerin solution is used as a gel base.
- In pharmaceuticals, CMC serves as a thickener and emulsifier.
- CMC solutions, after thickening, are used in flotation and ore processing.
- In Ceramic IndustryCMC is used as an adhesive for green bodies, a plasticizer, a suspending agent for glazes, and a color-fixing agent.
- In ConstructionCMC improves water retention and strength.
- In Food IndustryHigh-substitution CMC is used as a thickening agent in ice cream, canned foods, instant noodles, and as a foam stabilizer in beer. It is also used as a thickener, binder, or shaping agent in jams, syrups, fruit drinks, snacks, and ice cream beverages.
- In PharmaceuticalsSuitable viscosity CMC is used as a binder for tablets, a disintegrant, and a suspending agent in various formulations.
Packaging and Storage
Storage Conditions: Keep tightly sealed, protected from light, avoid high temperatures, and store in a dry, cool, well-ventilated place.
Packaging: Bulk packaging in 25 kg cardboard barrels, small samples in 1 kg foil bags, and custom packaging available upon request.
Transportation: Shipped via courier or logistics, typically delivered within three days domestically by courier and within five days by logistics. Quotes usually include domestic shipping costs.
Shelf Life: Two years.
