Natural paint (paint)
As natural colors will paint called (wall paints, lacquers and oils) from natural raw materials, mainly renewable, renewable and mineral raw materials are produced. The criteria for natural colors are: the voluntary full declaration of the ingredients, non-toxicity of the color "toxicity is defined here in such a way that no health risk can arise for humans or the environment and the entire product fits into ecological cycles", waste avoidance, avoidance of mineral oil products, as well as the "Usability" of the product. The designation “natural color” is not regulated by law.
Types and composition
Colors based on linseed , soy or sunflower oil are offered under the name natural colors . Linseed oil in particular was and still is the most important natural binder for oil paints . Raw and boiled linseed oil has been used in art painting since ancient times. Linseed oil has been known as a preservative for wood and iron since the Neolithic . Naturally pure linseed oil paint, which consists of boiled linseed oil and mineral pigments, has been used as a preservative paint since the 15th century . Small additions of metal oxides serve to accelerate the oxidation and hardening of the linseed oil to Linoxyn . Especially in the context of monument preservation , since the importation of pure, solvent-free linseed oil paints from Sweden, the repair of historical components, such as half-timbering, windows, doors and wooden facades, has been possible again according to tried and tested historical specifications. The proportion of non-natural ingredients in natural colors is also not regulated by law in Germany and is the responsibility of the manufacturers. Many products differ in the proportion of their natural raw materials, but they cannot be called natural products because they are not harmless to health. While synthetic ingredients such as azo pigments , biocides and anti-skin agents are often used, some manufacturers largely or completely dispense with synthetic additives. So come for nature paints Citrus base next to vegetable oils and natural resins and essential oils earth and mineral pigments used for natural water-based paints also contained are surfactants biogenic.
In varnishes based on vegetable oils, cobalt compounds are added as drying accelerators in small amounts as organically bound additives. An alternative without any health effects is currently not available.
Alternatives based on natural substances are also possible for other coating materials. In the case of emulsion paints, casein is used as a base material, which is tinted with vegetable colors.
properties
Natural colors differ from synthetically produced colors in some properties. For example, natural resins and oils in paints for surface treatment of wood can penetrate further into the substrate due to their smaller molecule sizes than synthetic resins. This increases the anchoring in the substrate and the substrate adhesion and prevents flaking. The drying time of oil-based natural paints is usually much longer (around one day) than the solvent-based paints or acrylic paints. Not all color tones of the RAL color system can be mixed exactly with pure natural colors , which is why natural colors are more often mixed according to NCS .
literature
- Gerd Ziesemann, Martin Krampfer, Heinz Knieriemen: Natural colors. Aarau (Switzerland) 1996, ISBN 3-85502-523-1 .
- Kurt Schönburg: Natural substances in buildings. Properties, application. Publisher: German Institute for Standardization e. V. -DIN-, Beuth Verlag, 2010, 280 pp. ISBN 978-3-410-17355-7 .
Individual evidence
- ↑ Gerd Ziesemann, Martin Krampfer, Heinz Knieriemen, Natural Colors , AT Verlag 1996, ISBN 3-85502-523-1 .
- ^ State Office for the Preservation of Monuments in Hesse: Building consultant leaflet Windows in Hesse - preservation and addition , worksheet 1, Wiesbaden 2005