Silicone alkyds, applications

Silicone alkyds are etherification products of alkoxy-polysiloxane oligomers and the free hydroxyl groups of alkyd resins (67, 68). The property improvements and applications are similar to those of the alkyd-silicone blends, with the added advantage of incorporating the stable —Si—O—C— strucmre into the alkyd molecules. The preferred silicone oligomers are those with high phenyl contents, and... 

Where circumstances suggest the use of a more conventional type of finishing paint with better tolerance of site application conditions than the above, silicone alkyd enamels should be considered. 

MAJOR POLYMER APPLICATIONS nitrocellulose, melamine, polyester, acrylics, silicone, alkyd, epoxy, PVC, EPDM, NR, SBR... 

In most coatings, the silicone resin is copolymerized with another resin to form silicone/alkyd, silicone/acrylic or silicone/polyester enamels. The silicone/alkyds are used for air-drying coating applications, whereas the silicone/polyester resin is for heat-cured applications [78]. 

Uses. There are about forty to fifty organic peroxides commercially available in more than seventy formulations designed for specific applications which include (1) initiators for vinyl monomer polymerizations, and copolymerizations of monomers such as vinyl chloride, ethylene, styrene, vinyl acetate, acrylics, fluoroolefms and buta-dienestyrene (2) curing agents for thermoset polyesters, styrenated alkyds and oils, silicone rubbers and poly allyl diglycol carbonates ... 

There are important modifications of alkyds that help in specific applications. Phenolics can be added to improve film hardness and water resistance, but these confer increased yellowing tendencies on the final coating. Silicones impart heat resistance and exterior durability. Styrene increases the drying speed. Methyl methacrylate when added gives faster drying properties and improves the color and durability of the coating. 

The most common and widely used thermoset molding compounds are classified as follows (a) alkyd, (b) allylic (diallyl phthalate), (c) amino (melamine and urea), (d) epoxy, (e) phenolic, (f) polyester, and (g) silicone. There may be other specialty thermoset resin materials used on specific applications. 

Silicone resins with high phenyl contents may be used with medium or short oil alkyds as blends in air-dned or baked coatings to improve heat or weather resistance the alkyd component contributes to adhesion and flexibility. Applications include insulation varnishes, heat-resisianl paints, and marine coatings. 

In this book I have confined discussion to those polymeric materials which are cured by chemical reaction and which have found widespread application in the construction industry. As such, the book covers materials based on epoxies, polyurethanes, silicones, polysulphides, alkyds and polyesters. In addition, there is a chapter on hybrid polymer systems and one on acrylics. It is true that acrylic emulsions are not strictly thermosetting polymer systems, but their widespread use and importance made their exclusion difficult. These materials find use as coatings, sealants, adhesives, grouts, flooring compounds, repair compounds and waterproofing agents. 

Among the countless number of applications of polymers, the construction industry is one which utilises several polymeric materials. In this book I cover those polymeric materials which are single or bicomponent systems and are cured at ambient temperature either with the aid of curing agents or atmospheric moisture. The various polymers used in manufacturing such products include epoxies, polyurethanes, acrylics, silicones, polysulphides, alkyds and polyesters. As a result of innovation, new technologies exist which utilise more than one polymer in a single product. Such systems are discussed in Chapter 10, on hybrid polymers. 

MAJOR POLYMER APPLICATIONS rubber, PE, alkyd, acrylics, silicone... 

MAJOR POLYMER APPLICATIONS pol5nirethane, epoxy, silicone, polychloroprene, PSF, acrylics, PVC, polyesters, alkyd, fluoroelastomers, NR, SBR... 

MAJOR POLYMER APPLICATIONS polyurethanes, alkyd, acrylics, silicon PVC... 

DIN 53183 defines an alkyd resin as follows Alkyd resins are synthetic polyester resins produced by esterifying polyhydric alcohols with polybasic carboxylic acids. At least one of the alcohols must be trihydric or higher. Alkyd resins are always modified with natural fatty acids or oils and/or synthetic fatty acids. In order to obtain particular application technology properties, alkyd resins may be additionally modified with compounds such as resin acids, benzoic acid, styrene, vinyltoluene, isocyanates, acrylic, epoxy, or silicone compounds. ... 

Examples of synthetic resins include phenol-formaldehyde formulations, which withstand boiling water or slightly higher temperatures and are used in the chemical industry in the form of multiple coats, baked on, for resisting a variety of corrosive media. Silicone and polyimide resins are useful at stiU higher temperatures. Alkyd resins, because of favorable cost, fast-drying properties, and durability, have found wide application for protecting the metal surfaces of machinery and home appliances. 

Heat resistance for pigments for coatings was tested in an alkyd/ melamine system below 200 C, in a silicone resin above 200 C. Pigments for plastic application were tested in PE-HD at a pigment Ti02 ratio of 1 10... 

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