Metal primer

Heat-reactive resins are more compatible than oil-soluble resins with other polar-coating resins, such as amino, epoxy, and poly(vinyl butyral). They are used in interior-can and dmm linings, metal primers, and pipe coatings. The coatings have excellent resistance to solvents, acids, and salts. They can be used over a wide range of temperatures, up to 370°C for short periods of dry heat, and continuously at 150°C. Strong alkaUes should be avoided. 

Uralkyds have superior adhesion, hardness, abrasion resistance, durabiHty, and chemical resistance to the unmodified alkyds. They find appHcations in wood floor finishes, marine coatings, metal primers, and maintenance paints. 

Water-borne adhesives are preferred because of restrictions on the use of solvents. Low viscosity prepolymers are emulsified in water, followed by chain extension with water-soluble glycols or diamines. As cross-linker PMDI can be used, which has a shelf life of 5 to 6 h in water. Water-borne polyurethane coatings are used for vacuum forming of PVC sheeting to ABS shells in automotive interior door panels, for the lamination of ABS/PVC film to treated polypropylene foam for use in automotive instmment panels, as metal primers for steering wheels, in flexible packaging lamination, as shoe sole adhesive, and as tie coats for polyurethane-coated fabrics. PMDI is also used as a binder for reconstituted wood products and as a foundry core binder. 

Non-corrosion-inhibiting primers Corrosion-inhibiting primers Inorganic barrier primers Rubber to metal primers... 

The spraying process provides a method of treating steel with coatings of zinc or aluminium, which can afterwards be painted. A combination of such a metallic primer and a good peunt system is the most effective means of combatting corrosion of constructional steelwork at a reasonable cost that is yet known. 

Red lead, zinc chromate, calcium plumbate and zinc dust were for many years of special importance as pigments for metal primers. When dispersed in raw or lightly-treated linseed oil, the first three possess the ability to inhibit the corrosion of mild steel and will function very well on wire-brushed rusted surfaces. In other media the tolerance towards rusted surfaces decreases with decreasing quantities of available oil, but performance on clean steel will usually be maintained and often improved. 

Barium chromate is used as a pigment in paints, ceramics, coloring glasses, fuses, and porcelains as a corrosion inhibitor to prevent elecrochemical corrosion at the joints of dissimilar metals in safety matches in metal primers in ignition control devices in pyrotechnic compositions and as an initiator for explosives. 

Phenolic c Metal primer, marine enamels, tank and drum lining... 

RC failure at the polyurethane cement interface CP failure at the cover cement primer interface CM failure at the metal primer interface R failure in the polyurethane... 

Check surface preparation techniques Use robust metal primer Avoid dissimilar metal contacts upon installation of finished bonded parts Avoid dissimilar metals in abrasion cleaning operation, i.e., steel grit with aluminum... 

Epoxy-based primers are commonly used in the aerospace and automotive industries. These primers have good chemical resistance and provide corrosion resistance to aluminum and other common metals. Primer base resins, curing agents, and additives are much like adhesive or sealant formulations except for the addition of solvents or low-viscosity resins to provide a high degree of flow. 

Corrosion protection by an inhibitive primer may be envisaged as shown in Figure 1.67. Inhibitive metal primers are designed with relatively high pigment volumes to allow sufficient water absorption to dissolve the passivating inhibitor and yet prevent aggressive ions such as chloride which interfere in the passive oxide formation process. 

In dip coatings the article is completely immersed in a large tank containing a certain quantity of paint to be applied. The article is then pulled out excess coating drains back into the dip tank. This technique is used for metal primer application such as motorcar bodies. 

Finishes are also described by the function of the paint. A primer is used to coat the original surface. Its major functional property is good adhesion. Protection against corrosion is an especially important characteristic of metal primers. Hiding is a secondary function. 

Use Metal primers, bottle cap coatings, food can coatings, appliance coatings. 

Use Marine paints, metal primers, polishing compounds, pigment in rubber and plastic products, theatrical rouge, grease paints. 

In pigmented coatings, phenolic varnishes find use as vehicles for porch and deck paints where moisture and abrasion resistance are of utmost importance. Their moisture resistance and good metal adhesion make them useful vehicles for metal primers. In concrete paints they outperform most other oil-containing vehicles due to their better alkali resistance. 

Solution vinyl systems have been used for many years to coat metal parts. Since we have a volatile organic solvent in the system, we have to ensure that (1) the tank remains cool and (2) we have a small liquid surface to prevent premature solvent evaporation. The carboxyl-containing vinyl terpolymers do not need an additional vinyl-to-metal primer. 

Emtal . [Engelhard] Talc filler, rein-forcer for thermosets, thermophutics, thermoplastic elastomers in caulks and sealants, dry-wall comp., adhesives, printing inks, paints, metal primers dusting agent few tacky rubber compds. 

Versaprime. [Southm Coatings] Universal metal primer. 

Versaprime. CSouifam Coatings] Uni-verbl metal primer. 

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