Application Status Of Titanium Dioxide In Coatings
The paint is mainly composed of four parts: film-forming substances, pigments, solvents and additives. The pigments in the paint have a certain hiding power. It can not only cover the original color of the coated object, but also give the film a bright color. Realize the decorative effect of lighting and beautification. At the same time, the close combination of pigment and curing agent with the substrate can enhance the mechanical strength and adhesion of the coating film, prevent cracking or shedding, and can increase the thickness of the coating film, prevent the penetration of ultraviolet rays or moisture, and improve the coating film Anti-aging and durability performance, extend the service life of the coating film and the protected object, and the white pigment is the largest in the pigment. The performance of the white pigment requires good whiteness, good grinding and wettability, good weather resistance, and chemical stability Good, small particle size, high hiding power and color reducing power, good opacity and gloss.
Titanium dioxide is one of the most widely used white pigments in coatings. Its output accounts for more than 70% of inorganic pigments, and its consumption accounts for 95.5% of the total consumption of white pigments. At present, about 60% of titanium dioxide in the world is used to make various coatings, especially rutile titanium dioxide, most of which is consumed by the coating industry. The paint made of titanium dioxide has bright colors, high hiding power, strong tinting power, low dosage, and many varieties. It protects the stability of the medium and can enhance the mechanical strength and adhesion of the paint film, prevent cracks, prevent ultraviolet rays and Moisture prolongs the life of the paint film. The color matching of almost every pattern in the colorful pattern paint is inseparable from titanium dioxide. Different types of paints for different purposes have different requirements for titanium dioxide. For example, powder coatings require good dispersion. Rutile-type titanium dioxide and anatase-type titanium dioxide have low tinting power and strong photochemical activity. When used in powder coatings, the coating film is prone to yellowing. The rutile-type titanium dioxide produced by sulfuric ACID method has moderate price, good dispersibility, and coloring. Strong force, low dosage, many varieties, protect the stability of the medium, and can enhance the mechanical strength and adhesion of the paint film, prevent cracks, prevent ultraviolet rays and moisture from penetrating and extend the life of the paint film.
Water-based coatings refer to the volatile substances in the coating formulations, most of which are water-based coatings. With the increase of people`s awareness of environmental protection and the stricter environmental regulations, water-based coatings have become popular like solvent-based coatings, requiring titanium dioxide whiteness and Good dispersibility, high hiding power, color reducing power, high weather resistance, low content, etc. At present, most of the titanium dioxides on the market are general-purpose titanium dioxides, which can be used for solvent-based coatings, and have hiding power and color reduction. Good strength and other advantages, very suitable for indoor powder coatings. Titanium dioxide for outdoor powder coatings requires good weather resistance in addition to good dispersibility, hiding power and color reducing power. Therefore, titanium dioxide for outdoor powder coatings is generally a general-purpose titanium dioxide, which can be used for solvent-based coatings and water-based coatings. However, after all, there are essential differences between water-based coatings and solvent-based coatings. These general-purpose titanium dioxides The dispersion effect of white powder in water-based coatings is not very good. Therefore, in order to make titanium white powder well dispersed in water-based coatings, it is necessary to select the surface treatment method of titanium dioxide in a targeted manner.
Architectural coatings require acid resistance, alkali resistance, water resistance, and moisture resistance. They must have good adhesion on rough or smooth base surfaces. In addition to the good optical properties and pigment properties mentioned above, the titanium dioxide used in architectural coatings is required to have high weather resistance and strong chalking resistance, especially for exterior wall architectural coatings.
