Yuan Lei's Little Knowledge | Performance Requirements and Types of Fillers for Coatings

Release time:

2024-06-12 14:54

Yuan Lei's Little Knowledge | Performance Requirements and Types of Fillers for Coatings

Fillers in coatings are usually white or slightly colored pigments with a refractive index less than 1.7. It has the basic physical and chemical properties of pigments used in coatings, but due to its refractive index being similar to the film-forming material, it is transparent in coatings and does not have the coloring and covering power of coloring pigments. It is an indispensable pigment in coatings.

Due to the fact that the majority of fillers come from natural ore processing products, which have good chemical stability, wear resistance, water resistance, and are inexpensive, they play a skeleton role in coatings. By filling, the thickness of the coating is increased, and the mechanical properties of the coating are improved, playing a role in durability, corrosion resistance, heat insulation, and extinction.

On the other hand, using it as a way to reduce the manufacturing cost of coatings, utilizing its low price and much lower price than color pigments, while meeting the coverage of the paint film, adding physical pigments appropriately to supplement the volume of color pigments in the paint.

Main functions and functions

1. Play a skeleton and filling role in the paint, increase the thickness of the paint film, and make the paint film full and solid;

2. Adjust the rheological properties of coatings, such as thickening and anti precipitation;

3. Improve the mechanical strength of the paint film, such as enhancing wear resistance and durability;

4. Adjust the optical properties of the coating, change the appearance of the coating film, such as extinction;

5. The film-forming substance undergoes a chemical reaction to form a whole, which effectively blocks the penetration of light, improves its water and weather resistance, and prolongs the service life of the coating;

6. As a volume filler in coatings, reducing resin usage and lowering production costs;

7. It plays an auxiliary role in the chemical properties of the coating, such as enhancing rust prevention, moisture resistance, flame retardancy, etc.

Performance requirement 

Different types and grades of coatings have different technical requirements for fillers, but the general requirements for fillers used in coatings are as follows.

1. High whiteness, especially in coatings with high requirements for film color, the whiteness is generally required to be above 93%.

2. Easy dispersion not only helps to reduce the energy consumption and time required for grinding and dispersion during coating production, but more importantly, it is beneficial for the performance of the coating, as the dispersion of fillers and pigments has a direct impact on the film performance.

3. Low oil absorption value, low oil absorption value can increase the critical pigment volume concentration of coatings, save resin base materials, adapt to the requirements of modern high solid coatings that meet environmental protection requirements, prepare pre dispersed filler slurries with higher content, and match pigments with decreasing oil absorption value. The oil absorption value of commonly used non-metallic mineral fillers in coatings.

4. There should be a definite particle size and a narrow particle size distribution, and the sieve residue should be as low as possible. Nowadays, coatings require fillers to have a fine or even ultra fine particle size in many application fields, so as to exert their spatial separation effect in the coating, make the pigment particles in the coating evenly distributed, and maximize the potential of pigments for covering, coloring, and rust prevention, playing a partial role in replacing pigments.

5. It can make the coating have good rheological properties, prevent sedimentation during storage, facilitate construction and film formation, and form a smooth and flat coating film.

6. It should have good compatibility with the base materials, pigments, and other additives in the paint, but at the same time, it should also have a certain degree of inertness and not react chemically with the above components.

7. Having an appropriate specific surface area, as it affects the viscosity, rheological properties, dispersion stability, settling properties, and oil absorption of coatings.

8. Having a certain particle shape and crystal morphology, the coating has optical properties such as a certain refractive index and ensures the functionality of the filler in the coating.

coating,requirement,type,filler,High whiteness

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