| 摘要 |
In the process of spraying in a cubicle having a water-rinsed rear wall the cubicle waste water is separated by ultrafiltration into permeate and lacquer-containing residue. The permeate is recycled. Fresh spraying composition is fed-in. The lacquer preferably is an alkyd resin, an acrylic resin, a polyvinyl acetate resin, a silicone resin, a copolymer thereof, a mixed polymer thereof or a mixture thereof. The spraying composition comprises a component for preventing coalescence, preferably one or several aliphatic amines having an average molecular weight of 75 to 133 or mixtures or derivatives thereof, and a component for retardation of the drying. If the lacquer is capable of being emulgated or dispersed in water, the spraying composition and/or the cubicle waste water preferably comprises a component for stabilizing the emulsion or dispersion. A component for adjusting the throughput in the ultrafiltration is admixed to the cubicle waste water, preferably a derivative of glycol or of a higher alcohol. The spraying composition and/or the cubicle waste water additionally may contain a biocidal component. The conductibility of freshly fed water is kept below a predetermined limiting value preferably of 10-4 (Omega)-1cm-1, which is preferably achieved by reverse osmosis. The lacquer-containing residue of the cubicle waste water is enriched by removing water until its lacquer content is about equal to that of fresh spraying composition. The enrichment and reuse may proceed in essentially continuous or discontinuous manner, in the latter case the lacquer-enriched residue is stored intermediately.
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