Block stains and tannins with ASK emulsions

Block stains and tannins with ASK emulsions

Wednesday, 13 March, 2024

ASK Chemicals, a German manufacturer of emulsions, has developed the NECOWEL 4300/4350/4400 family of alkyd emulsions for the formulation of stain blocking paints.

They are medium oil oxidative drying alkyd emulsions modified with cationic groups.

From a chemical standpoint, cationic groups have been successfully integrated into a more or less anionic alkyd resin system. The result is a stable paint system with excellent blocking properties against stains such as nicotine, felt-tip pens, food waste and also wood constituents such as tannins and phenols.

These are modified emulsions with a patented technology with which we can formulate wall or wood paints with low shrinkage and excellent application properties. They have good substrate wetting properties, are easy to formulate and are safe to use in production, without incompatibility problems with other components in the formulation.

These emulsions are free of VOCs, do not contain cosolvents and are APEO-free, whilst also being neutralised with ammonia.

Compared to other alternative cationic emulsions, NECOWEL’s patented technology  has a pH value of between 5.5-6.5 (an alkaline pH value should be avoided to prevent the formation of ammonia salts in dyes). This results in good compatibility with additives and different types of pigments, colouring pastes and fillers.

We have three emulsions to formulate with: NECOWEL 4300, 4350 and 4400.

  • NECOWEL 4350 is a version of 4300 without free formaldehyde.
  • NECOWEL 4300/4350 have higher chemical resistance and higher wet scrub resistance.
  • NECOWEL 4400 is faster drying.

NECOWEL 4300/4350/4400 offer excellent wetting and application properties. A formulation diluted in water can be used as a tannin-blocking wood impregnation agent.

Although they can be used as a primer and topcoat, a primer formulated with Necowel 4000 series resins has good drying properties and can be overcoated with a standard paint. No bleeding of water-soluble substances to the surface will occur.

For further information about these products, please contact our Team of Technical Sales Advisors.




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