Application of Superfine Talc Powder in Coatings and Paints
The nature of ultrafine talc powder is a natural hydrous magnesium silicate mineral. It is inert to most chemical reagents and does not decompose when in contact with acids. It is a poor conductor of electricity, low thermal conductivity and high thermal shock resistance. It does not decompose at a high temperature of 900°C. These excellent properties of talc make it a good filler, which can be used to fill plastics or be used as an excellent filler in paints and paints.
1. Talc powder and industrial coatings
The main advantages of coating talcum powder in coating applications are: high natural whiteness, generally do not need chemicals for bleaching, can improve whiteness, softness, smoothness, gloss, and can prepare high-solid content coatings.
Talc can be used in many industrial coatings, especially primers. Talc powder can be used in whole or in part for the steel structure primer, which can improve the precipitation of the paint, the mechanical force of the coating film and the recoatability. Talc is preferred for many manufactured and flash primers and vehicle paints. Sheet magnesium silicates, including talc, are suitable for use in metallic primers because of their ability to improve sanding and water resistance, which may arise from the fact that the flake particles extend the path of moisture through the film.
Because talc has excellent physical and chemical properties such as lubricity, anti-adhesion, flow aid, fire resistance, acid resistance, insulation, high melting point, chemical inactivity, good hiding power, softness, good gloss, and strong adsorption, it is widely used in The application in coatings is mainly reflected in: in coatings, talc powder is used as a filler, which can play a skeleton role, reduce manufacturing costs and improve the film hardness of coatings. It can mainly increase the stability of the product shape, increase the tensile strength, shear strength, bending strength, pressure strength, reduce deformation, elongation, thermal expansion coefficient, high whiteness, uniform particle size and strong dispersion.
As a filler of polyurethane waterproof coatings, talc powder can not only reduce the volume shrinkage of the coating during curing, improve the wear resistance and adhesion of the coating, reduce the cost, but also make the coating have good storage stability and heat resistance.
The influence of talcum powder as a filler on the elastic elongation and tensile strength of waterproof coatings shows a similar trend: that is, with the increase of fillers, the elastic elongation and tensile strength of waterproof coatings both increase first, and a maximum value, and then continue to decrease until an optimal value appears in the middle. Considering from the molecular point of view, when the amount of talcum powder is extremely small, the particles without talc powder will be dispersed in the middle of the macromolecular chain segments, so the attraction between the macromolecular chain segments cannot be reduced, and the macromolecular chain segments are very weak. Difficult to move, resulting in small elastic elongation of waterproof coating; with the increase of the amount of talcum powder, its small particles will continue to fill between the chain segments of macromolecules, the movement of the chain segments is strengthened, and the elastic elongation When the small inorganic particles of talcum powder just fill the gaps between the macromolecular chains, the defects in the curing system of the waterproof coating are the fewest, and the tensile strength and elongation of the waterproof coating reach an optimum. value; but too much filler will weaken the force between the macromolecules and reduce the cohesive energy of the waterproof coating, resulting in a decrease in tensile strength.
2. Application of talcum powder in latex paint
Latex paint is one of the essential paints in our lives. Now our country often uses latex paint in the decoration process. Good quality latex paint is very popular. And if you want latex paint to meet the high quality requirements, you must rely on the help of talcum powder.
Adding talcum powder to latex paint can increase the hardness of the paint, so that the difficulty of construction can be reduced when adding latex paint, so that the aesthetics of building construction can also be improved. Talc powder is an essential and important part of paint, and only the paint with talcum powder can have better corrosion resistance. But it should be noted that talcum powder is not added in unlimited quantities. If too much talcum powder is added to the latex paint, it will precipitate the latex paint and reduce the quality of the paint, and if it is used too little, it will affect the practicality and beauty of the latex paint.
In addition, when adding talcum powder, attention must also be paid to its adding temperature, otherwise it will also affect the quality of latex paint.