Paint systems alkyds

Stripping of top coats soaked by rain or sea-water has occurred with alkyd-resin-based paint systems, mainly on ships. The risk of such intercoat failure is reduced if the time interval between application of coats is reduced, but is best controlled by modification of the alkyd resin with a proportion of a different material. 

They are applied by wet paint spray techniques and have the advantage, over other paint systems, of long-term flexibility. Conventional alkyd systems may have an initial degree of flexibility, but within 12 months outside become rigid and then crack due to thermal expansion and contraction of the substrate. This phenomenon is less likely to occur with a well formulated vinyl solution. 

Table 4 Relation between the heat stability of azo pigments in an alkyd-melamine resin baked system, their fastness to overpainting in this paint system, and their bleed resistance in plasticized PVC.

Conditions to be met in oven drying enamels depend also on the composition of the binder. Paint systems containing melamine-formaldehyde or urea-formaldehyde resins, for instance, harden by polycondensation with other resins, such as epoxy resins, short-oil alkyd or acrylic resins at elevated temperatures. Baking is carried out at temperatures between 100 and almost 200°C and may last from a few minutes to more than an horn. A general trend towards energy conservation has shifted public attention towards binders which require low baking temperatures. 

The thermoelectric fire tests confirmed the fire-resistance of the navy stock fire-retardant interior white and experimental red deck paints (systems 1 and 5) and demonstrated the flammability of the navy deck gray, white enamel, vinyl-alkyd, and alkyd-chlorinated rubber paints, systems 2, 3, 4 and 6. 

Solvents used for paint removal are able to dissolve or considerably swell physically drying binders (e.g., vinyl chloride copolymers, cellulose nitrate, polyacrylates) and chemically cross-linked coatings (e.g., oil-based paints, dried alkyd resins, cross-linked polyester-melamine resins, cross-linked epoxy and isocyanate coatings) [14.237]. A combination of dichloromethane with low-boiling ketones or esters is particularly suitable. Small amounts of high-boiling solvents with a low volatility (e.g., tetrahydronaphthalene, solvent naphtha, methyl benzyl alcohol, or benzyl alcohol) are added to these mixtures to retard evaporation and increase the solvency. Modern paint removers do not contain chlorinated hydrocarbons, they are formulated on the basis of high boilers (e.g., dimethylformamide, dimethyl sulfoxide, propylene carbonate, and yV-methylpyrrolidone) in combination with alcohols and aromatics, or consist of aqueous, frequently alkaline or acidic systems. 

Chem. Descrip. Sulfated castor oil CAS 8002-33-3 EINECS/ELINCS 232-306-7 Uses Thickener, rheology control agent for solv.-type paint systems, high-solids alkyd coatings... 

Chem. Descrip. Hydrogenated castor oil CAS 8001-78-3 EINECS/ELINCS 232-292-2 Uses Thickener for petrol, solv. paint systems thixotropic and antisettling agent for high-solids coatings (alkyds, epoxies, PU, acrylics, PVC copolymers)... 

Uses Wetting agent, dispersant for org. pigments, carbon bik. magnetic media, iron oxides for nonaq. systems, paints/coatings, alkyd, actyiic, epoxy, urethane, polyester, lacquers, printing inks, textiles resinous/ polymeric food-contact coatings food-contact paper/paperboard cellophane for food pkg. 

PA Guide 4 Guide to Maintenance Repainting with OU Base or Alkyd Painting Systems... 

Chemical resistance The cured paint film (alkyd/melamine system, 10% pigmented) is exposed to solutions of 2% hydrochloric acid and 2% sodium hydroxide for 24 hours. The gray scale according to DIN EN 20105-A02 (formerly DIN 54001) was used to access color changes... 

Painting System Specification No. 1.04 Three-Coat Oil-Alkyd (Lead-and Chromate-Free) Painting System for Galvanized or Non-Galvanized Steel (with Zinc Dust-Zinc Oxide Linseed Oil Primer)... 

These specifications cover alkyd painting systems for commercial blast cleaned or pickled steel. These systems are suitable for use on parts or structures exposed in Environmental Zones lA (interior, normally dry) and IB (exterior, normally diy). The color of the finish paint must be specified. 

Painting System Specification No. 2.05 Three-Coat Alkyd Painting System for Unrusted Galvanized Steel (for Weather Exposure)... 

This specification covers a complete silicone alkyd painting system for structural steel. This system is suitable for use on parts or structures exposed in Environmental Zone 2A (frequently wet by fresh water), including high hiunidity, infrequent immersion, and mild chemical atmospheres. The primary virtue of this system is the exterior durability and minimum deterioration of the silicone alkyd finish as shown by chalk resistance, gloss retention, and color retention. In addition, the finish paint allows for a choice of colors. 

In the case of water-borne coatings, the film properties have also been shown to depend on the nature of the alkylating alcohol. For example, ethanol etherified amino resins have been shown to exhibit high hardness and poor film appearance compared to HMM resins. This has been attributed to the poor compatibility of such resins with alkyd resins. Mechanical properties of paint films based on HMM resin vary depending on whether the paint system is water-borne or solvent-based." This difference has been assigned to the different network structures due to the blocking of... 

The selection of TSA systems and functional monomers are generally made on the basis of performance criteria for the final paint system. For example, curing temperatures and the performance of different thermosetting acrylic resin systems vary depending on the type of curing mechanism. Such a dependence, compared to older alkyd-melamine systems, has been demonstrated by Brendly et alP and can be summarized as in Table 4. 

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