Volatile organics content

Degussa AG introduced a new silane VP Si 363 as a successor of Si 69 for the tire industry [44]. Tire tests have proved that this new silane reduces the rolling resistance by 13% compared with mixes containing Si 69. In addition, volatile organic content (VOC) emissions were reduced by 80% compared to the use of Si 69 or Si 266. 

The solvent should not contain substances that contribute significantly to the production of photochemical smog and troposphere ozone. The volatile organic content of the product, as used, should not exceed 50 g/L. None of the components of the product will have a maximum incremental reactivity (MIR) exceeding 1.9 g Ofg of compound (the MIR for toluene). MIR values can be obtained from the maximum incremental reactivity list found in Appendix VII of the California Air Resources Board s California Exhaust Emission Standards and Test Procedures for 1988 and Subsequent Model Passenger Cars, Light-Duty Trucks and Medium-Duty Vehicles as amended on September 22, 1993. 

A 100% solids system is needed (no volatile organic content). 

Hybridisation techniques enable the solids content of PUDs to be increased. However, this is achieved at the expense of volatile organic content, although this is satisfactorily low (Howarth and Manok, 1996). 

Potential GA degradation products and impurities are listed in the Appendix, Table A4. Impurities may account for up to 28% of the volatile organic content of munitions-grade GA. The... 

Table VI. EPA Guidelines for Maximum Volatile Organic Content of Coatings...

In the development of maintenance and marine coatings, the emphasis has been on the development of low-solvent, or solvent-fi ee, coatings to satisfy EPA volatile organic content standards. Thus liquid epoxy systems based on polyamidamines have been developed. Epoxies have also been formulated as powdered coatings, thus completely eliminating solvents. 

Fillers are applied with electrostatic spraying devices (fast-rotating bells) to give dry film thicknesses of about 40 pm. Waterborne fillers with polyester-melamine binders (primer surfacers) have been developed to reduce the volatile organic content. They yield a film thickness of 30 pm after a prereaction time of 10 min at lOO C and a reaction time of 20 min at 165 °C. The properties of the films are similar to those formed by solventborne paints. More recently, waterborne fillers based on blocked isocyanates have been developed. Field trials have shown that their mechan-ieal resistance is very good. 

ASTM D 3960-87, Determining Volatile Organic Content (VOC) of Paints and Related... 

These new dithiol-modified liquid polysulfide polymers have lower viscosity and improved compatibility with formulating ingredients (e.g., plasticizers, pigments, and fillers). Thus dithiol-modified liquid polysulfide polymers give more latitude in the formulation of high-performance sealants, adhesives, and coatings. The volatile organic content (VOQ of such products is lower than that of products formulated by conventional liquid polysulfide polymers. 

Research is now strongly centred on prodncing primers with low volatile organic contents, by using water as the primary solvent or dispersion medium or actual water-based primers where the organic solvent content is zero. For similar reasons of Environment and the impact of adhesive technology, a move to non-chromate systems is also under way. 

Reduction in the volatile organic content (VOC) of coatings, contributed by the solvents present, is now required because solvents, principally hydrocarbons, contribute through a reaction chain to an increase in ground level pollution (photochemical ozone). The hole in the ozone layer in the stratosphere concerns chlorofluorocarbons (CFC) and is a very different issue. Also of concern to formulators is the removal of lead, chromium and cadmium, which are long term environmental pollutants in paint residues. 

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