Table 42. Coating components. 



VEHICLE 



PIGMENT 



ADDITIVES 



RESIN 



PLASTIC I SER 



SOLVENT 



Alkyd 



Glycols 



Prime 

 Dilutents 



Prime 

 Extenders 



Surfactants 

 Drying Agents 



Epoxy 







Color 





Coal Tar 

 Vinyl 





Mineral 

 Spirits 



MEK Toluene 



Corrosion 

 Inhibitor 



Anti-Skinning 

 Agents 



Other 











Coatings are usually named or designated by their resin systems. For 

 example, an alkyd coating contains an alkyd resin, an epoxy coating contains 

 an epoxy resin, and a silicone alkyd contains an alkyd resin as the primary 

 resin system with additions of silicone resins. Plasticisers are added for 

 modifying the properties of the resin. Solvents are used for dissolving or 

 dispersing the resin for manufacture. Solvents are also useful for develop- 

 ing and controlling application properties of a coating. For example in a 

 cold climate, the solvent must be volatile enough to evaporate at low 

 temperatures. Conversely, in tropic or desert climates, the solvent must 

 be slow enough (less volatile) to allow the coating to flow out and properly 

 cover the hot surface before it volatilizes. 



The pigments are the finely ground solids which are added to give 

 coating body, color, and corrosion-inhibitive properties. Special additives 

 are added, usually in small amounts, to give the coatings many special 

 properties. 



Table 43 lists generic coating types suitable for use on concrete and 

 steel (both immersed and nonimmersed) . Selection of a recommended coating 

 system for a given service condition is determined from specific properties 

 of coating types, described below. 



(1) Alkyds. Alkyds are formed when oil is combined chemically 

 with glycerol phthalate. They cure by reaction with oxygen and have 

 excellent wetting properties and fair to good weather resistance. Alkyds 

 have poor resistance to acids and alkalies and only fair abrasion resistance. 

 They should be used only for mild environments in selected harbor locations. 

 They should not to be used where surfaces are continuously damp or immersed 

 in water. 



(2) Silicone Alkyd . Silicone alkyds possess properties similar to 

 alkyds as defined above but possess somewhat better heat resistance, 

 weather resistance, and gloss retention. They cannot be used for immersion. 

 Also they are softer and are less resistant to abrasion. 



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