Modified acrylic topcoat

A typical formulation for a modified acrylic topcoat is given below ... 

Chem. Descrip. Vinyloxazoline diester of an unsat. fatty acid Uses Monomer for polymerization, improving pigment wetting and resin props, (adhesion to metal, weathering, corrosion resist.), for use in alkyd resins, acrylic/vinyl resins, car repair/primer systems gloss aid for acrylic topcoats applied on SER-AD FX 521 modified alkyd primers Properties Gardner 11 max. clear liq. dens. 940 kg/m (20 C) vise. 275 mPa s (20 C) acid no. 10 max. flash pt. > 100 C 100% act. 

Alternatively PVC can be crosslinked with dithiocarbamates to reduce plasticiser migration, and a copolymer of PVC can also be crosslinked when modified with acrylic groups. Applying acrylic topcoats such as Rohm s Degalan also helps to minimise loss through the smface. 

Topcoats. For some applications such as chest freezers or vacuum cleaners, alkyds are still employed. These evolved from oil-modified types to the oil-free polyesters that have good stain resistance, high gloss, and excellent flexibility. But until recently, the thermosetting acrylic was the hallmark of appliance coatings. Acrylics exhibit excellent hardness, adhesion, chemical... 

The raethylolated acrylamide type has been widely used in appliance finishes. These are cross-linked with melamine or epoxy modifiers and form hard, chemically resistant finishes. Detailed discussion of thermosetting acrylics can be found in References 2 and 8. Recently, topcoats based upon high-solids liquid polyesters have replaced thermosetting acrylics in response to environmental... 

Modified phenolic resins are condensation products of the resol type which contain other starting materials besides phenol and formaldehyde (e.g., acrylic monomers). The phenolic component itself is often modified (alkyl- or arylphenols). Modification with rosin is the most important one. The compatibility of phenolic resins with other binders can be substantially improved by modification. Rosin-modified phenolic resins may be combined with linseed oils and alkyd resins. Examples of use include putties, priming coats, rust protection paints, and colored topcoats. 

They are synthesized from polymers of primarily polymethacrylate, acrylate esters, and polyethyl acrylate (Fig. 13.2). Acrylate resins are very stable in oxygen and UV light and are resistant to weathering and frequently used in the automobile industry as topcoats. Water-based acrylics are used as household paints. For ultraviolet resistance and improved weathering, acrylic resins are used as modifiers for epoxy and alkyd coatings. 

Chem. Descrip. Modified thermoplastic acrylic Uses Pigment dispersant for high perforrtrance nonaq. coatings, UV-cured automotive OEM dear coats, asphaltic roof coatings, traffic paints, anticorrosive primers, marine topcoats, wood furniture coatings Features Solv.-free... 

Uses Acrylic, modifier to improve hardness and solv. resist, for wood flat stock primers and topcoats... 

Uses Polyurethane polyol used in soh/.-based systems modifier for acrylic, polyester, and alkyd resins high-solids coatings, machinery and equip, coatings, appliance coatings, automotive topcoats, paper and wood coatings, aerospace coatings Features Lower VOC... 

Chem. Desaip. Amine-modified bisphenol A epoxy diacrylate oligomer Uses Epoxy-acrylic for clear coatings for paper and plastics, topcoats for wood, screen and lithographic ink vehicles Features Improves prod, performance (cure response, chem. resist., flexibility, abrasion resist., gloss, adhesion to plastic substrates)... 

Uses. Acrylics, both lacquers and enamels, were the topcoats of choice for the automotive industry from the early 1960s to the middle 1980s. Thermosetting acrylics are still used by the major appliance industry. Acrylics are used in electrodeposition and have largely replaced alkyds. The chemistry of acrylic-based resins allows them to be used in radiation curing applications alone or as monomeric modifiers for other resins. Acrylic-modified polyurethane coatings have excellent exterior durability. 

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