General processing information
2-component PUR coatings may be the right choice for many applications if the following points are observed:
- The mixing ratio and pot / processing life of the PUR coating mixes must be strictly observed. Exceeding the processing time of paint mixes that are in a fluid state is not always apparent by gelling or an increase in the viscosity. Unfavourable parameters relating to air humidity and temperatures have a negative impact in the processing time of the mixture and full hardening of the paint coat.
- The mixing ratio for Remmers PUR coatings must be stated in volume parts which is why it is recommended using the 2K mixing beaker set (Art.-No. 4270 – 4273).
- Careful mixing before processing both components and, if necessary thinning, is important for good durability and an even look of the painted surfaces. This can be guaranteed by using the Remmers Patent Disperse (Art.-No. 474701 / 474702).
- Always keep the package tightly closed. PUR hardeners react to humidity in the air.
- Remmers PUR coatings should only be mixed with the recommended thinners. Using soiled thinners means that the PUR hardener cannot create an adequate cross-linked layer on the paint film.
- Water and the re-wetting agent UN-894, e.g. as cleaning agent residues in spray units, may not come into contact with PUR coatings. The spray units must be cleaned with a wash-thinner WV-891.
- Bleached wood should be dried for at least 48 hours before painting. Only Remmers PUR coating systems that have been processed with the hardener PUR H-280 may be used on these surfaces.
- PUR caotings are non-reversible when hardened; they do not dissolve after brief contact with the internal solvent. The time frame in which a paint can be painted over without intermediate sanding is oriented on the drying period stated in the respective technical code of practice. After the end of the drying time, the PUR coatings should always be freshly sanded and cleaned of dust.
- The minimum temperature during the drying and hardening phase lies at 18°C for a time of 48 hours to achieve optimum wetting and low residual emissions. This is particularly important in the case of high wetting PUR coating systems in a mixing ratio of 5:1, 4:1 etc.
- The use of a coating system with low amounts of solvents e.g. Remmers Aqua paints, should always be considered. This particularly applies to parts that are subject to the Deco-paint guide line (ChemVOCFarbV).