Pigments surface treatment

The 1982 Swedish ban on the use of cadmium as a pigment, surface treatment and stabiliser, backs up this conclusion. 

Cohesiveness is the main factor influencing flow of organic pigment powders (OPP) in operations such as IBC discharge. The purpose of this study is to establish (a) the relationship between grain size and cohesiveness of pigment powders and (b) the effect that pigment surface treatments (especially abietyl resin) have on cohesiveness. 

Although kaolins are easily wetted by both oil and water, surface treatment may sometimes be used to enhance the oleophilic properties. The kaolin in paint may represent 20—30% of the pigment. 

Alternatively because of the degree to which it both reflects white light and absorbs in the ultraviolet, it may inhibit photodegradation. Which of these two possibilities predominates depends on a variety of factors including the concentration of the TiOj pigment used, the nature of any surface treatments, and the extent to which the polymer itself is able to resist photodegradation. 

Various finishes can be achieved — gloss, satin (or egg-shell) or matt. This is accomplished by the addition of particles of size 1-5 pm of, for example, silica, china clay or the white pigment, TiCK The degree of mattness depends on various factors, such as particle size, surface treatment of the particles, rate of film formation, and the polymer composition, e.g., urethane/acrylate compared with epoxy/acrylate. The former requires smaller particles larger particles cannot be used as they create a rough surface. 

Organic surface treatments, on titanium dioxide pigments, 25 26 Organic syntheses, 13 412—113 acid and base catalysts for, 24 182 advantages of fermentation over, 11 6 enzymes as catalysts for, 10 307 high pressure in, 13 438—139 ozone use in, 17 810-811 silylation in, 22 695-696 Organic tellurium compounds, 24 414-415, 422... 

Incorporated in plasticized PVC, P.B.15, like other phthalocyanine pigments, is usually entirely fast to migration. Moreover, it provides excellent lightfastness. P.B.15 also finds use in various types of PUR foam materials as well as in rubber. Its redder and frequently cleaner shade compared to corresponding stabilized types makes it an equally useful pigment for other media. This applies especially for water-based systems. Textile printing, paper mass coloration, paper surface treatment, and paper pulp are areas of application as suitable for the use of P.B.15 as office articles, including colored pencils, blackboard chalks for schools, and water colors. 

The use of P.B.15 1 in various types of paints has for many years been hampered by unsatisfactory flow behavior. Newer methods involving surface treatment of the pigment with suitable agents have made it possible to improve the rheology in certain media enough to afford pigments which satisfy the use requirements. 

Under the designation P.B.15 4, the Colour Index lists (3-Copper Phthalocyanine Blue types which are stabilized towards flocculation. These products show largely the same coloristic and fastness properties as P.B.15 3 types, but often exhibit much better rheology. As with stabilized a-Copper Phthalocyanine Blue types, stabilization through surface treatment has proven to decrease the solvent fastness of 3-Copper Phthalocyanine Blue, sometimes considerably so, making the pigment more sensitive to aromatics, alcohols, ethylene glycol, and ketones. 

A very wide variety of pigments are used to color PBT and can also be considered as fillers when used at high levels. The most common pigment is titanium dioxide which can be used in a variety of particle sizes and with various surface treatments [38]. 

For instance in azo pigment manufacture, the crude product is given some form of surface treatment, such as with rosin, to control crystal growth, control aggregation and to aid in dispersion. 

When mixed-phase rutile pigments are used in special paint systems, (e.g., stoving or acid-catalyzed lacquers), inorganic surface treatment in an aqueous medium can improve the gloss and flocculation properties. For example, an aqueous pigment suspension is first treated with a surfactant, and then coated with metal hydroxides or oxide hydrates [3.93],... 

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