Many polyurethane dispersions contain n-methyl pyrrolidone (NMP), because it is often required in the production process. Also, it facilitates film formation. California Proposition 65 and European legislation require special labeling for products containing NMP. For example in Europe, products containing 5% NMP or more have to be labeled as toxic. A worldwide trend in the paint industry is to eliminate NMP from any coating formulation.
Bayer MaterialScience has developed a new generation of high performance polyurethane dispersions without solvent in its supply form.
Bayhydrol range of NMP-free polyurethane dispersions for wood coatings
The Bayhydrol® product range includes polyurethane dispersions that are largely solvent-free. For film-forming, there still is often a need for a co-solvent, however, there is a wide window of co-solvent content to be selected with these products. In many cases, the total solvent content of an NMP-free formulation is lower than compared to conventional formulations.
Some products examples for polyurethane dispersions:
Bayhydrol® XP 2558 is particularly elastic, but still hard and chemically resistant, it can be used not only in woodcoatings (parquet, furniture) but also on other flexible and less flexible substrates. In addition, it shows a very good compatibility with polyacrylates. The same applies to the fatty acid modified grades Bayhydrol® XP 2557 and Bayhydrol® XP 2593/1. These dispersions yield very hard and chemically resistant coatings for parquet flooring as well as interior joinery coatings. Bayhydrol® UH XP 2719 is an elastic and hard dispersion with fast blocking resistance, especially interesting for joinery and furniture coatings.
A sample starting formulation:
RR 6694Waterborne one component clearcoat (Bayhydrol® UH 2557)
Additional starting formulations are available on request.
All raw materials for wood coatings in this brochure:
Many polyurethane dispersions contain n-methyl pyrrolidone (NMP), because it is often required in the production process. Also, it facilitates film formation. California Proposition 65 and European legislation require special labeling for products containing NMP. For example in Europe, products containing 5% NMP or more have to be labeled as toxic. A worldwide trend in the paint industry is to eliminate NMP from any coating formulation.