Study On Preparation Of Silica Matting Agents By Silica Gel Modification

Matting agents are additives commonly used in paints to form fine and rough surfaces on the paint film,allowing diffuse reflection of light to achieve half-light or even matt effect,and the matt surface can also mask the defects of some utensils to make the appearance uniform.Consistent.With the improvement of people’s living standards and environmental protection awareness,water-based paint products have gradually become the dominant market,and they have also promoted the development of matting agent products for water-based coatings.Due to its good optical properties and chemical stability,silica has become the first choice for many high-grade coating matting agents.At present,silica matting agent products can be classified into dry and wet methods according to the preparation method.Dry-process silica is mainly fumed silica,its preparation process is simple,and the particle size is even and controllable,but its cost is high.The wet method includes the gel method and the precipitation method.The silica prepared by the gel method has large pore volume,concentrated pore size distribution,high transparency,but low oil absorption value,long process flow,and complicated production process;and the precipitation process conditions are relatively Simple,the product has high oil absorption value,but the pore volume is small and the transparency is poor.The content of this paper is as follows:1.C-type silica gel was used as a raw material.After the smashing,grading,reaming,and surface modification,an extinction silica suitable for water-based paint was prepared.The morphology,infrared absorption spectrum,particle size distribution and pore volume of the prepared silica matting agent were characterized and tested for its extinction performance in coatings.The results showed that the prepared silica matting agent had a concentrated particle size distribution with a median particle size d50 of 5.73μm.The silica gel was reamed with n-butanol at 95°C,the pore volume was 1.90 mL/g,and the DBP oil absorption value was 264 cm3/100 g.2.Silica coupling agent was used to modify the surface of silica to obtain a matting agent with good matting effect,high dispersity and stability.The optimal modification condition modifier was 15 wt%of SiO2 mass.Duration 3.5 h.When adding 5 wt%of the polyester resin to the coating,the matting agent can produce a good matting effect,reaching the extinction level of the same type of products at home and abroad,and the coating can be stored for a long time without hard precipitation,and the gloss of the film is not great.influences.3.The in-situ modified micro-sized silica matting agent was directly synthesized by using a micro-dispersing reactor.The influence of the concentration ratio of water glass and sulfuric acid solution,the pH at the end of the reaction,and the aging time on the pore volume of the prepared silica particles was studied.The silane coupling agent ethanol solution was used for in-situ modification,and the micron-sized material was successfully prepared.Porosity silica matting agent.