Carboxymethyl Cellulose CMC
Carboxymethyl cellulose, or CMC for short, is used in many sectors (ceramics, paper, food, textiles, water-based paints, adhesives, etc.), but it is most commonly used in glaze production in the ceramic industry. It is used to prevent glaze settling and to increase its binding strength. The longer the chain length, the greater its binding strength.
Carboxymethyl Cellulose, or CMC for short, is derived from softwood pulp or cotton linter (seed). It is commonly produced and sold in granular and powder form.
CMC Uses in the Ceramic Industry:
CMC is used in ceramic glazes for the following properties:
CMC is generally used in glazes at a concentration between 0.3-0.5%.
1- To prevent the glaze from settling, it is either added to the mill with the raw material or opened and added later to the vat.
2- CMC is used to increase glaze binding. The glaze must bind within itself to maintain its homogeneous structure.
3- CMC is used to reduce glaze runoff and smooth the surface.
4- CMC is used to delay glaze drying.
5- CMC is used to increase the glaze's viscosity, i.e., reduce its fluidity.
HOW TO USE CMC
CMC is a water-soluble material. To add later, add 2g of powdered CMC (2%) to 100g of water, stirring gently to prevent clumping.
CMC is preferably dissolved in hot water, which will allow it to set more quickly.
The container should be opened until no particles remain, and it must be filtered through a 150-200 micron coarse sieve before use.
Because CMC is a sensitive material, it is best to prepare it before use. Its binding properties decrease with age.
Because CMC is an organic material, it burns at 200-250 degrees Celsius and is removed from the body. Therefore, it does not cause stains or defects on the glaze surface. It only facilitates the application of the glaze during application and reduces defects.
The binding properties and effectiveness of CMC used in ceramics depend on the length of the CMC chain length and the degree of aggregation. As the chain length increases, CMC becomes more effective (50%), and as it decreases, it becomes less effective (20%).
CMC is used in many sectors (Textiles, Food, Cosmetics, Detergents, Pharmaceuticals, Ceramics, etc.), and the quality and structure of CMC used for each sector vary.
STORAGE:
Because CMC is a water-sensitive product, it should not be allowed to come into contact with water. Once in contact with water, it will stick together and become unusable.