Polyurethane dispersions for conventionally drying waterborne parquet coatings

For high traffic floors a two-component waterborne coating based on a Bayhydrol® dispersion in combination with a Bayhydur® polyisocyanate offers the best performance. The selection of an appropriate grade of a waterdispersible Bayhydur® polyisocyanate the coating system can be adjusted to the performance needed.

A selection of raw materials for one- and two-component parquet applications:

Waterbased dispersions:

	Type	Solids in %	pH	Viscosity mPas at 23°C	Characteristics
Bayhydrol® UH 2558	Polyurethane dispersion	35	8.0	<100	Tough, but flexible, good mechanical and chemical resistance
Bayhydrol® UH 2557	Polyurethane dispersion	37	8.0	<100	Solvent-free, fatty acid modified, outstanding abrasion resistance
Bayhydrol® UH 2593/1	Polyurethane dispersion	35	8.0	<100	Solvent-free, fatty acid modified, good mechanical and chemical resistance, excellent grain wetting
Bayhydrol® UA XP 2631	Polyurethan- dispersion	37	7.5	<100	High abrasion resistance, good yellowing resistance and adhesion, very hard, solvent-free
Bayhydrol® A 2651	Polyacrylate dispersion	41	-	2000	For high-gloss systems, excellent grain wetting
Bayhydrol® AH XP 2741	Polyacrylate dispersion	40	7.0	< 100	For one-component clearcoats, topcoats and primers, outstandig chemical resistance, good hardness

Polyisocyanate crosslinkers for waterbased dispersions:

	Type	Solids in %	% NCO on solids	Viscosity mPas at 23°C	Characteristics
Bayhydur® 305	HDI- polyisocyanate	100	16.2	6500	For glossy, transparent coatings, easy formulation
Bayhydur® 3100	HDI-Ppolyisocyanate	100	17.4	2800	Hydrophilic crosslinker for polyurethane dispersions to enhance the property profile
Bayhydur® XP 2759	IPDI- polyisocyanates	70	11.0	6500	Hydrophic crosslinker in combination with HDI-based grades to enhance drying properties

A sample starting formulation:

RR 6674

water-based two component clear coat (Bayhydrol® UH 2558, Bayhydur® 305)

Additional starting formulations are available on request.

Please have a look at:
Versatility of solvent free PUD for coating wood / Wood Coating Congress 2008 in Amsterdam

NMP free Polyurethane-Polyacrylate dispersions
A new generation of NMP-free dispersions are polyurethane and acrylic-modified polyurethane dispersions.
An example of this product line is Bayhydrol® UA XP 2631. Get more information here.