Direct zinc oxide's needle-like structure, through its unique physical morphology and chemical properties, significantly improves the suspension properties of coatings and enhances the overall performance of coatings.
The steric hindrance of the needle-like structure is a key factor in enhancing suspension performance. Direct zinc oxide's needle-like particles have a large aspect ratio, forming a three-dimensional network within the coating system. This structure effectively hinders the settling of pigment particles. When dispersed in a medium, the intersecting network of needle-like particles increases the viscosity of the system and, through physical hindrance, slows the settling rate of pigment particles. Compared to spherical particles, needle-like particles have a larger contact area, making them more likely to form a stable dispersion and reducing the delamination caused by settling.
The oil absorption properties of the needle-like structure further enhance suspension stability. Direct zinc oxide's needle-like morphology results in higher oil absorption, allowing it to absorb more resin or solvent, forming a dense coating. This coating not only increases the weight of the pigment particles but also prevents particle aggregation through steric hindrance. During paint storage, needle-shaped particles with high oil absorption effectively maintain system uniformity, preventing variations in coating performance due to pigment settling. Furthermore, the oil absorption of the needle-shaped particles modulates the coating's rheological properties, ensuring excellent brushability and leveling during application.
The interaction between the needle-shaped structure and the substrate enhances coating adhesion. Direct zinc oxide's needle-shaped particles penetrate deep into the micropores of the substrate surface, creating a mechanical anchoring effect. This physical bond strengthens adhesion between the coating and the substrate, making the coating more resistant to wear and peeling. Furthermore, the three-dimensional skeleton formed by the needle-shaped particles within the coating effectively disperses stress, preventing cracking or detachment due to external forces. This property is particularly important in anti-corrosion and marine coatings, significantly extending the coating's service life.
The chemical stability of the needle-shaped structure ensures long-term coating performance. Direct zinc oxide inherently exhibits excellent light, heat, and weather resistance, and its needle-shaped structure further enhances these properties. Under ultraviolet light, the needle-shaped particles effectively scatter and absorb UV light, preventing discoloration or chalking of the coating due to photoaging. Furthermore, the chemical inertness of the needle-shaped structure makes it less likely to react with other coating components, thereby maintaining the coating's chemical stability. This stability is particularly prominent in exterior paints, allowing them to withstand harsh climates.
The needle-shaped structure's rust-preventing mechanism expands the coating's application range. Direct zinc oxide's needle-shaped particles form coordination complexes with carboxylate ions in the coating, reducing the film's sensitivity to water. This characteristic gives it a unique advantage in metal anti-corrosion coatings: the needle-shaped particles form a dense zinc-titanium compound layer, effectively blocking the penetration of corrosive media. Furthermore, the alkalinity of the needle-shaped structure neutralizes trace acidic substances in the coating, preventing electrochemical corrosion of the metal substrate. This rust-preventing mechanism makes direct zinc oxide an ideal additive for marine and industrial anti-corrosion coatings.
Direct zinc oxide's needle-shaped structure significantly improves the coating's suspension properties through multiple mechanisms, including steric hindrance, oil absorption, substrate interaction, chemical stability, and rust-preventing mechanisms. This enhances the coating's adhesion, weather resistance, and corrosion resistance. These properties make it widely used in interior paints, latex paints, anti-corrosion paints and marine paints.
