Pigment anti-corrosive

Paints are complex formulations of polymeric binders with additives including anti-corrosion pigments, colors, plasticizers, ultraviolet absorbers, flame-retardant chemicals, etc. Almost all binders are organic materials such as resins based on epoxy, polyurethanes, alkyds, esters, chlorinated rubber and acrylics. The common inorganic binder is the silicate used in inorganic zinc silicate primer for steel. Specific formulations are available for application to aluminum and for galvanized steel substrates. 

Improvements in process and quality control made significant contributions to the transition from iron to steel as the major ferrous construction material over a century and a half ago. For most of that time red lead was relied upon, and not without a remarkable degree of success, as the rust-inhibitive pigment in anti-corrosive paints. In the last twenty years, however, there has been a similar dramatic change from such simple paints as red lead to synthetic polymer coatings which have as complex a technology as steel manufacture itself. 

Anticoccidial activity, of polyether antibiotics, 20 135-136 Anticoccidials, 20 135—136 Anticorrosion agents, molybdenum compounds in, 17 39 Anticorrosion coatings, organic titanium compounds in, 25 134 Anti-corrosion metallic coatings, 1 713-714 Anticorrosion pigments, 19 411 Antidegradants... 

Carter, E.V. (1988) A new synthesis process for the manufacture of lamellar iron oxides for pigment use in anti corrosive coatings. J. Oil and Colour Chem. Assoc. 5 132-133 Carty, P. White, S. (1999) Flammability studies on plasticised chlorinated poly(vinyl) chloride. Polymer Degradation Stability 63 455-463... 

Etzrodt, G. (1993) Anti corrosion pigments. In Buxbaum, G. (ed.) Industrial inorganic pigments. VCH Weinheim, 186-206 Evanko, C.R. Dzombak, D.A. (1998) Influence of structural features on sorption of NOM-analogue organic acids to goethite. Environ. Sci.Techn. 32 2846-2855... 

Lead chromate pigments are mainly used as corrosion inhibitive pigments. These pigments are of low opacity and can be combined with higher opacity pigments for use in primers. Zinc chromate, also an anti-corrosion pigment, is used in metal pretreatments such as wash primer, which also promotes adhesion to aluminum and steel. 

Austin, M. J., Inorganic Anti-Corrosive Pigments, ASTM MANUAL 17, American Society for Testing and Materials, Philadelphia, USA, 1995, p. 238... 

Bravo, C. A., Non Toxic Ion-Exchange Anti-Corrosion Pigments, ABRAFATl Congress Proceedings, Sao Paulo, Brasil, 1995, p. 770... 

Barium chromate is used in the following applications as an anti-corrosive agent, as a pigment in paint, in ignition control devices, in safety matches, as a constituent in pyrotechnic compositions, and as a coloring agent in ceramics. 

Liu, WM. 1998. Efficiency of Barrier-Effect and Inhibitive Anti-Corrosion Pigments in Primers. Mater. 

Zinc orthophosphate, Zn3(P04>2-41120 (Hopeite), forms the basis of an important group of dental cements and it is also used as an anti-corrosive pigment (Chapter 12.8). On heating, the tetrahy-drate loses water in two stages ... 

The salts FeH2P30io and CrH2P30io are formed in similar dehydration sequences, and the acid salts of all three metals exist in various isomorphous and polymorphic forms. Both CrH2P30io 2H2O and AIH2P3O10 2H2O find use in anti-corrosive pigment formulations. Both salts can form intercalation compounds (Chapter 12). 

Anti-corrosive pigments may be used in etch primer formulations (see above), or as components of the closely related anti-corrosive paints which are based on alkyd resins or other organic binders. Among the compounds used for the latter are [22]... 

Green CrP04 3H2O is a good long-term inhibitor and is usually employed in connection with other anti-corrosive pigments in order to overcome its poor immediate protective action. 

What are termed multiphase anti-corrosive pigments are based on mixtures of inorganic phosphates and sparingly soluble organic corrosion inhibitors. 

Two-pack etch primers usually contain an anti-corrosive pigment. In traditional formulations, zinc tetroxychromate was used. Current products, however, are mostly chromate-free, in response to environmental pressures. The zinc tetroxychromate has been replaced with a small amount of less toxic anti-corrosive pigments, such as zinc phosphate. Anticorrosive performance may be compromised, to a degree, by such substitutions. 

On metals, while promotion of adhesion of the multi-coat system is equally important, an added requirement is the control of corrosion. In metal primers, anti-corrosive properties are achieved by incorporating either pigments that are anodic to the metal substrate or pigments, such as zinc phosphate, that inhibit corrosion by other mechanisms. 

Micaceous iron oxide n. Naturally occurring iron ore which resembles mica only in appearance and not chemically. It is converted to a grayish pigment, which has value as a constituent of anti-corrosive paints and protective coatings. Density, 4.90 g/cm (40.8lb/gal) O.A., 11/200 lb hardness (Mohs), 6.0 ph, 7.7. 

Primer prl-m9r (1819) n. First complete coat of paint of a painting system apphed to a surface. Such paints are designed to provide adequate adhesion to new surfaces and are formulated to meet the special requirements of the surfaces. The type of primer varies with the surface, it condition, and the total painting system to be used. Thus, primers for new wood and certain other surfaces must provide for exceptional absorption of the medium. Primers for steelwork contain special anti-corrosive pigments, such as red lead, zinc chromate, zinc powder, etc. A coating applied to a surface, prior to the application of an adhesive, to improve the performance of... 

Red lead (15c) n. Pb304. Pigment red 105 (77578). Bright red to orange-red tetrox-ide excellent opacity with good properties as a primary constituent of anti-corrosive primers for iron and steel. Density, 8.9 g/ cm (74.2lb/gal) O.A., 7-9. 

Primers are applied to the filled or unfilled surface, to promote adhesion, to prevent absorption of later coats by porous surfaces and to give corrosion resistance over metals. As their name implies, they prepare the base material for further paint application. Special pigments improve the anti-corrosive properties. 

Anti-corrosive action Inorganic All anti-corrosive pigments are inorganic... 

This resin will be partly neutralized with acetic or lactic acid, and co-emulsified with a blocked isocyanate cross-linker (p. 225). This type of resin is now the standard protective primer coating on the majority of the world s motor cars. Pigmentation will include anti-corrosive pigments. 

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