Automotive solvent release

In a thermoplastic acrylic automotive coating, a CAB is used as the pigment dispersion medium and at 15% concentration based on polymer weight provides better sprayability, increased cold crack resistance, better pigment control, better solvent release, and improved exterior durability. (See Table IX.)... 

Combustion of fuels produces and releases pollutants such as hydrocarbons, carbon monoxide, oxides of nitrogen, particulate matter, sulfur dioxide, and greenhouse gases such as carbon dioxide and nitrous oxide. Air pollutants are also released by some household products—for instance, paints, paint strippers, solvents, wood preservatives, aerosol sprays, cleansers and disinfectants, moth repellents, stored fuels, and automotive products. 

Car paints are cured with heat in special oven lines. Electrodeposition coatings (used as anticorrosive primers) contain only small amounts of volatile organic compounds (VOC), whereas intermediate and topcoats release considerable amounts of VOCs. Intermediate coats based on waterborne resins have been developed to decrease VOC emission and are already being used in some automotive plants. Basecoats, as part of base-clear topcoat systems, contain very high amounts of volatile organic solvents. Waterborne basecoats were developed more recently to lower this source of solvent emission. Some car manufacturers are operating pilot lines with the aim of introducing waterborne basecoats into their production processes. Many car producers in the United States and Europe have already switched their topcoat lines over to waterborne basecoats [11.3]. 

MAJOR APPLICATIONS Antifoam fluids, lubricants, protective gels, and elastomers and sealants in applications exposed to hydrocarbon fuels and oils and organic solvents in the automotive and aerospace industries. Longer fluorocarbon side-chain fluorosilicones are available with developing use as release coatings for silicone-based adhesives. 

Chem. Descrip. Acrylic polymer in xylene/mineral spirits Uses Defoamer, leveling agent for solvent-based coatings, baking enamels (automotive, coil), high build urethanes and epoxies Features Offers effective air release, exc. recoatability Properties Liq. 40% solids Use Level 0.2-1.5% let down or post-add Disparlon 4200-10 [Kingind.]... 

Preformed Tapes. Preformed tapes of butyl, usually vulcanized, are extruded semisolid sections with pressure-sensitive adhesion. Since they are 100% solid, there are no problems of shrinkage or solvent evaporation. Sold in rolls interlined with release paper, they are often used together with liquid sealants or solid spacers, shims, etc. They vary from low cost, highly polybutene-extended tapes for trailers and mobile homes, to partially or fully vulcanized butyl rubbers with little polybutene content for high-rise glazing and automotive windshield sealants. 

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