Preparation And Application Of Palygorskite-red Iron Oxide Composite Pigment

In recent years,with the recovery of the global economy,China’s construction,coatings,inks,rubber and other industries have begun to show a trend of growth,the demand for inorganic pigments has been significantly improved.With the continuous improvement of the country’s environmental protection requirements,as well as the continuous improvement of people’s awareness of environmental protection,heavy metal inorganic pigments such as lead and cadmium have gradually withdrawn from the market,and environmentally friendly inorganic pigments have gradually begun to shine.Iron oxide is an important inorganic colorant,which is used in ink,paint,ceramics,architecture and other fields widely due to its advantages of weather resistance,corrosion resistance and strong shading ability.Among the global color inorganic pigments,iron oxide pigments account for 85%of the production,but its market share is only about 50%.Iron oxide red（α-Fe₂O₃）pigment is one of the most widely used iron oxide pigment.However,compared with other red pigments,the color light and coloring strength of iron oxide red pigments are lacking,which also greatly limits its application scope and high-value application orientation.Attapulgite（Pal）is a kind of magnesium-rich aluminosilicate clay mineral,with a one-dimensional rod and layer chain structure,has abundant reserves and belongs to the dominant resource minerals in China.But its current application is mostly limited to low-value fields,and the development and application of high value are less.In this paper,Pal/α-Fe₂O₃composite pigments were prepared by grinding method,and while improving pigment properties,high value-added applications for attapulgite were developed.The specific content is as follows:（1）Based on attapulgite nanorods,iron oxide red（model:190）particles are loaded,and the performance of composite pigments is affected by changing the particle size and distribution ofα-Fe₂O₃.The properties and structure of composite pigments are characterized by chromatic aberration analysis,X ray diffraction（XRD）,Ultraviolet and visible spectrophotometry（UV-vis）,scanning electron microscopy（SEM）and Fourier infrared spectroscopy（FT-IR）and other methods.The effects of grinding rate,grinding time,dispersant content,and the quality ratio of attapulgite and iron oxide red pigments on the properties of composite pigments were investigated.The results show that the iron oxide red in the composite pigment maintains a good crystal structure.The color performance of the composite pigment（cp8 Pal/α-Fe₂O₃）is closely related to the ratio of Pal toα-Fe₂O₃,and the composite pigment shows the best color performance when the mass ratio of Pal toα-Fe₂O₃is 1:8.The difference in redness of the color and light of the raw iron oxide red pigment isΔa=2.28,and the difference in redness of the coloring force isΔa=2.55.（2）Two groups of red waterborne polyurethane coatings were synthesized with cp8 Pal/α-Fe₂O₃composite pigment and 190 iron oxide red pigment as the pigment filler.Through a series of physical and chemical tests on the coating,the application effect of Pal/α-Fe₂O₃composite pigment in water-based coatings was explored,and the application effect of 190 iron oxide red was compared.The results show that the Pal/α-Fe₂O₃composite pigment can be stably dispersed in waterborne polyurethane,and the red waterborne coating formed by the two has good storage stability.Compared with iron oxide red pigments,Pal/α-Fe₂O₃compound pigments can give coatings better adhesion and corrosion resistance.（3）The anti-sintering ability of cp8 Pal/α-Fe₂O₃composite pigment and 190 iron oxide red pigment was tested by high-temperature calcination experiment.Experimental results show that cp8 Pal/α-Fe₂O₃composite pigment at 700°C chromatic difference valueΔE=0.43,900°C chromatic difference valueΔE=0.93,1100°C chromatic difference valueΔE=1.63,all less than 2,in line with the requirements of the ceramic industry and better than the performance of 190 iron oxide red pigments at the same temperature.