Calcium carbonate dispersant: a magical additive to improve material performance
In the field of material science and industrial applications, calcium carbonate, as a widely existing
inorganic compound, is widely used in coatings, plastics, rubber, paper and other
industries due to its unique physical and chemical properties. However, the small size and large
specific surface area of calcium carbonate particles easily lead to agglomeration,
which affects the performance and stability of the product. In order to solve this problem, calcium
carbonate dispersants came into being.
1. Definition and classification of calcium carbonate dispersants
Calcium carbonate dispersant is a chemical additive that can improve the dispersibility of calcium
carbonate particles in liquid media.
It forms an adsorption layer on the surface of calcium carbonate particles, changes the surface
properties of particles, improves the dispersion performance of particles in liquid media,
thereby preventing particles from agglomerating in liquid and maintaining a stable dispersion
state of particles.
According to different chemical compositions and mechanisms of action, calcium carbonate
dispersants can be divided into many types, including surfactants, polymer dispersants,
acid-base dispersants, inorganic dispersants, organic small molecule dispersants and polymer
modified dispersants.
These dispersants each have their own unique mechanisms of action and application fields.
2. Mechanism of action of calcium carbonate dispersant
Surfactant: By reducing the surface tension of the liquid, a thin film is formed on the surface of the calcium
carbonate particles, so that the particles repel each other and achieve a dispersing effect.
Common surfactants include sodium dodecylbenzene sulfonate (DBSA), sodium dodecyl sulfate (SDS), etc.
Polymer dispersant: Through the interaction between polymer compounds and the surface of calcium
carbonate, the attraction between particles is reduced and the dispersion is improved.
Common polymer dispersants include sodium polyacrylate (PAA), polyvinyl alcohol (PVA), polycarboxylates
and polyacrylates.
Acid-base dispersant: By adjusting the pH value of the solution, the charge state of the calcium carbonate
particles is affected, electrostatic repulsion is generated,
and dispersibility is improved. Commonly used acid-base dispersants include sodium hydroxide (NaOH),
hydrochloric acid (HCl), etc.
Inorganic dispersants: By increasing the charge on the surface of calcium carbonate particles, the electrostatic
repulsion is enhanced to prevent the particles from approaching and
flocculating. At the same time, it can also enhance the wetting degree of the particle surface and improve the
stability of the suspension. Common inorganic dispersants
include sodium hexametaphosphate and sodium disilicate.
Organic small molecule dispersants: including anionic, nonionic and cationic types. Ionic dispersants improve
the stability of suspensions through electrostatic repulsion of surface charges,
while nonionic ones rely on steric hindrance.
Polymer modified dispersants: change the surface properties of calcium carbonate particles through chemical
reactions to achieve particle dispersion. Polymers such as polyacrylates and
polymethacrylates react with calcium carbonate particles through chemical bonding to form a stable dispersion system.
3. Application of calcium carbonate dispersants
Paint and ink industry: The use of calcium carbonate dispersants can make calcium carbonate pigments evenly
dispersed in the matrix, prevent deposition or flocculation,
improve the covering power and scratch resistance of the coating, and reduce costs.
Plastic industry: Calcium carbonate dispersants can make the calcium carbonate used for filling evenly distributed
in plastics, improve the mechanical properties and appearance
quality of plastics.
Rubber industry: Adding calcium carbonate dispersants to rubber products can improve the wear resistance, aging
resistance and tensile strength of rubber.
Paper industry: Calcium carbonate dispersants make calcium carbonate evenly dispersed in pulp, improve the smoothness
and whiteness of paper, and reduce production costs.
Other industries: Calcium carbonate dispersants are also widely used in sealants, adhesives, ink carriers, waterproof coatings,
water-based coatings, interior and exterior wall coatings,
powder coatings, insulation materials, refractory materials and other fields.
IV. Selection and use precautions of calcium carbonate dispersants
When selecting calcium carbonate dispersants, it is necessary to consider the specific application scenarios and requirements
to ensure the best dispersion effect and stability.
At the same time, the following points should be noted when using:
Amount of dispersant: Excessive use of dispersants may result in poor dispersion effect or affect other properties of the product.
Therefore, the amount of dispersant should be reasonably controlled according
to actual conditions.
Method of adding dispersants: Different dispersants have different ways of adding. Some dispersants need to be added before
grinding, while others need to be added gradually
during the grinding process. Therefore, the product instructions should be carefully read before use to ensure that the dispersant
is added correctly.
Storage and shelf life of dispersants: Dispersants should be stored in a dry, ventilated, and cool place, avoiding direct sunlight
and high temperature environment.
At the same time, you should also pay attention to the shelf life of the dispersant and avoid using expired products.
