Solvent-free paints

Loop A continuous process for polymerizing aqueous emulsions of olefinic compounds such as vinyl acetate. Polymerization takes place in a tubular reactor (the loop) with recycle. Invented by Gulf Oil Canada in 1971 and further developed by several United Kingdom paint companies. It is now used for making copolymers of vinyl acetate with ethylene, used in solvent-free paints and adhesives. 

The increasing demand for solvent-free paints led to the introduction of water-based paints. Both in the production and in the application of this type of paint quite often a water-paint waste mixture results. Two examples are leftovers, diluted with (cleaning) water and water used in water curtains in spray booths, which becomes increasingly contaminated with paint. Using ceramic membranes with pore sizes of 0.1 micron [35], it is possible to concentrate the paint particles to a very high degree (35-65% dry matter) and at the same time produce an effluent containing less than 0.1% paint. This can be... 

Solvents and pigments need not always be present in a coating formulation. Solvent-free paints and pigment-free varnishes are also available. 

The low molecular mass binders have low solution viscosity and allow low-emission paints with high solids contents or even solvent-free paints to be produced. Here, the binder consists of a mixture of several reactive components, and film formation takes place by chemical drying after application of the paint. If chemical hardening occurs even at room temperature, the binder components must be mixed together shortly before or even during application (two- and multicomponent systems). 

Chem. Descrip. Polyacrylale copolymer sol n. in alkylbenzenes Uses Leveling agent for solvent-ba and solvent-free paints/coatings, industrial coatings... 

BYK -310 BYK -333 BYK -344 BYK -373 BYK -375 Crayvalac FLOW-100 welti agent, substrate solvent-free paints/coatings Addid 210... 

The tackiness of paint and varnish coatings may be reduced by the use of fast-drying film-formers or by fluid-bed application of a solvent-free paint. 

Tests on acrylic/styrene dispersions having varying minimum film forming temperatures demonstrate that when a suitable binder is used, solvent-free paints can be formulated, which exhibit weathering behaviour comparable to that of conventional solvent-based paints. Rutile titanium dioxide pigments are shown to have a greater influence on weathering resistance than the binder. 6 refs. 

BYK -357 BYK -359 BYK -392 air release agent, solvent-free paints/coatings BYK -357 BYK -359 BYK -392 air release agent, solvents Drewplus L-405... 

Ultrafiltration is currently dominated by two large apphcations, the recovery of electropaint waste water and the recovery of proteins from dairy wastes. The former application results from the use of solvent-free paints, especially for automobiles. These paints are electrostatically apphed. Any wash water is then processed to recover suspended pigments and other colloidal material. In the dairy industry, cheese whey can be concentrated and purified. In some cases, ultrafiltration concentrates valuable albumins that are lost in conventional processes. 

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