1.CMC Meaning
Carboxymethyl Cellulose Sodium (abbreviated as CMC) is a water-soluble cellulose ether and is widely used in industries such as food, medicine, daily chemicals, petroleum, textile and papermaking. As an efficient and multi-functional additive, CMC has excellent properties such as thickening, stabilizing, emulsifying and water retention. This guide will provide a detailed introduction to the raw material sources, application scope, production process and market prospects of CMC, helping customers have a comprehensive understanding of this important product.
2.The Historical development of CMC
In the early 19th century: Scientists discovered for the first time that cellulose could be modified by chemical methods.
In 1918, German chemists first synthesized carboxymethyl cellulose (CMC).
In the 1930s: Industrial production began, initially used in the adhesive and textile industries.
In the 1950s: Food-grade CMC was approved for use and became a food additive (E466).
In the 21st century, with the growth of environmental protection demands, the application of CMC in fields such as medicine and new energy has expanded rapidly.
Today, CMC has become one of the most widely used water-soluble cellulose ethers in the world, with an annual output exceeding one million tons.2. The raw material sources of sodium carboxymethyl cellulose
3. The source of raw materials for CMC
1Cotton staple fleece
Cotton linters are by-products of cotton processing. They have a high cellulose content (>90%) and high purity, making them the preferred raw material for producing high-quality CMC.
It is applicable to the production of pharmaceutical and food-grade CMC.
2) Wood pulp
It is extracted from wood through chemical or mechanical pulping processes, with cellulose content of approximately 70% to 85%.
It has a relatively low cost and is often used in the production of industrial-grade CMC, such as in oil drilling, textile printing and dyeing, and other fields.
(3) Other plant fibers
Materials such as bamboo and sugarcane residue can also be used as raw materials for CMC, but they are less applied and are usually used for products with specific requirements.
4. Application scope of sodium carboxymethyl cellulose
CMC, with its outstanding performance, plays an important role in multiple industries:
(1) Food industry
- Thickener: Used in ice cream, yogurt, jelly, etc., to improve the taste.
- Stabilizer: Prevents the stratification of beverages and extends the shelf life.
- Water-retaining agent: Retains moisture in bread and cakes to delay aging.
(2) Pharmaceutical industry
- Tablet binder: Enhances the formability and solubility of tablets.
- Pharmaceutical excipients: used for thickening and stabilizing ointments and gels.
- Artificial tears: As a lubricant to relieve dry eye syndrome.
(3) Daily chemical products
- Toothpaste: Endows the paste with appropriate viscosity and luster.
- Shampoo and body wash: Enhance consistency and improve the user experience.
- Cosmetics: Used for stabilizing and thickening lotions and facial masks.
(4) Petroleum industry
- Drilling fluid additive: Increase the viscosity of the mud and stabilize the wellbore.
- Fracturing fluid: Used for hydraulic fracturing in shale gas extraction.
(5) Textile and Papermaking
- Textile printing and dyeing: As a sizing agent, it enhances the cohesion of fibers.
- Papermaking sizing agent: Enhances the strength and water resistance of paper.
(6) Other applications
CMC is also widely used in industries such as ceramics, coatings, and building materials as a binder or rheology modifier.
5. The production process of sodium carboxymethyl cellulose
The production of CMC mainly includes steps such as alkalization, etherification, neutralization, purification and drying.
(1) Alkalization reaction
Cellulose reacts with sodium hydroxide (NaOH) to form alkaline cellulose.
Cell-OH + NaOH → Cell-ONa + H2OCell-OH + NaOH → Cell-ONa + H2O
(2) Etherification reaction
The reaction of alkali cellulose with sodium chloroacetate (ClCHCOONa) introduces carboxymethyl groups:
Cell-ONa + ClCH2COONa → Cell-O-CH2COONa + NaClCell-ONa + ClCH2COONa → Cell-O-CH2COONa + NaCl
(3) Neutralization and purification
Adjust the pH to neutral (6-8) with an acid (such as hydrochloric acid).
By-products (such as NaCl and sodium glycolate) are removed by water washing and alcohol washing.
(4) Drying and crushing
Powdered CMC was obtained by spray drying or fluidized bed drying.
Adjust the fineness (80 mesh -200 mesh) as required.
(5) Quality Control
- Degree of substitution (DS) : It measures the degree of carboxymethylation, usually ranging from 0.4 to 1.5, and for food-grade DS, it is ≥0.7.
- Purity: Detect the content of impurities such as chlorides and heavy metals.
- Viscosity: Different applications have different requirements for viscosity (for example, the viscosity of a 1% solution is between 10 and 10,000 mPa·s).
6. The market prospect of CMC
With the enhancement of environmental protection and health awareness, the market demand for CMC continues to grow:
- Food and Medicine: Natural and safe CMC as an alternative to synthetic additives.
- New energy and environmental protection: Used in emerging fields such as lithium battery separators and sewage treatment.
- Global market: It is estimated that the CMC market size will exceed 2 billion US dollars by 2025.
7. How to choose the right CMC products?
Customers need to consider the following factors when choosing CMC:
Application fields: Food grade, pharmaceutical grade or industrial grade
- Degree of substitution (DS) : High DS (>0.8) is suitable for high-viscosity requirements.
- Viscosity range: Low viscosity (<100 mPa·s) is used for beverages, and high viscosity (>1000 mPa·s) is used for drilling fluids.
- Solubility: Some products need to be dissolved in cold water immediately, while others need to be dissolved by heating.
8.Conclusion
Sodium carboxymethyl cellulose (CMC), as a multifunctional and environmentally friendly polymer material, plays an irreplaceable role in many industries. Whether it is food thickening, pharmaceutical excipients, oil extraction or daily chemical industry, CMC can provide efficient solutions. With technological progress, the application scope of CMC will be further expanded and the market prospects are broad.
