05/2013, Finished R&D Projects

Development of new primer systems for varnishes, paints and coatings on the basis of plant proteins as binders

  • funding program: ZIM-KF (BMWi)
  • term: 01.05.2013 – 31.08.2015
  • project partners: Kreidezeit Naturfarben GmbH

Initial position:

The use of synthetic polymers and their derivatives as a primer for the timber industry cause environmental impact due to Volatile Organic Compounds (VOC). With the movement “Green Coating”, for example, the plastics and paper industry is trying to find new binder agents on the basis of domestic raw materials. Some natural colors manufacturers use alternative substances as primer components, e.g. casein or shellac. Although these raw materials show the necessary qualities with respect to environment and sustainability, their technical use is very limited.
Studies have shown the following problems:

  • casein and shellac have to be decomposed with excipients;
  • some excipients are critical regarding classification / labeling, e.g. boron salt;
  • solutions of these raw materials are extremely susceptible to microbial degradation, following, the solutions must be possibly preserved;
  • both commodities show a high risk of embrittlement as well as shellacs lasting water sensitivity.


Within the project a suitable new primer component (binder) based on plant proteins will be developed for natural colors. The new primer system is part of the overall coating sector and should fulfill three important functions:

  • saturation of strongly absorbing substrates
  • consolidation of the substrates
  • creation of a bonding layer for subsequent coating.

A primer for natural colors should consist of renewable, local as possible and biodegradable raw materials without VOCs. It should be stable against microbial degradation to a certain extent. Furthermore, it shouldn`t completely seal the treated substrate to maintain a certain breathability (e.g. wood).
Due to its native structure and modifiability plant proteins are an interesting alternative for use as a binder. The globular protein fractions, albumins and globulins have extensive techno-functional properties.


To implement the desired properties, on the market available highly concentrated vegetable protein samples and other plant sources such as rapeseed / canola, fava beans, sunflowers and flax were tested. As oil component for the aqueous-oily undercoat were refined linseed oils, varnish and linseed oil / wood resin product tested. The requirements for the emulsification efficiency, the service life of the primer solution and the processing properties on wood can be achieved. The implementation of this procedure can be done by the project partner with a minimal investment.

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