PUDs for foam coatings available from Baxenden Chemicals

Citation

(2001), "PUDs for foam coatings available from Baxenden Chemicals", Pigment & Resin Technology, Vol. 30 No. 3. https://doi.org/10.1108/prt.2001.12930cad.003

PUDs for foam coatings available from Baxenden Chemicals

PUDs for foam coatings available from Baxenden Chemicals

Keywords Baxenden Chemicals, Polyurethanes, Coatings

Witcobond polyurethane dispersions (PUDs) for foam coatings formulations are reported to be available from Baxenden Chemicals.

Foam coatings are used in the textile and leather finishing industries for many familiar household items such as shoes, rainwear, carpets, upholstery fabrics, curtains (including blackout types), blinds, cloth wipes, synthetic leathers and filtration fabrics.

Polyurethane dispersions provide barrier properties (e.g. against wind and rain) or act as a durable binder (e.g. for solid additives such as pigments and flame retardants) to modify fabric handle and in textile adhesives.

The potential benefits claimed of foamed coatings, as distinct from solid coatings, include improved aesthetic and tactile effects – such as softer handle, reduced penetration and lower coating weights.

Witcobond 290H is described as a solvent-free, 60 per cent solids polyurethane dispersion, which can be formulated for high foam stability, good structure retention on drying and excellent coating properties. It is thought to be particularly suitable for mechanically foamed systems used in thin backcoatings, including high-quality curtain and upholstery fabrics and crushed foam coatings.

A similar product, Witcobond 755, is said to have lower modulus properties and provides even softer coatings for these applications.

Both products can reportedly be used on their own or as the principal binder in mixtures with other polymer dispersions (such as harder Witcobond grades, including Witcobond 769). They are said to impart properties such as abrasion, flex and wash resistance when suitably compounded. Generally, they are believed to be less tacky than alternative polymer latices of equivalent softness, especially when crosslinked. The foam structure and coating porosity can be varied by formulation changes, by controlling the degree of air entrapment, and by altering machine conditions (heat, pressure) for the crushing operation when this is required.

Baxenden Chemicals also has an active development programme on high-solids (generally 50-60 per cent) polyurethane dispersions for textile and other soft coating applications. These versatile dispersions are based on aliphatic diisocyanates (for good non-yellowing properties) and a choice of either polyester or polyether components, which provides a range of coating properties.

Details available from: PUDs Technical Dept, Applied Chemicals Division, Baxenden Chemicals Ltd, Tel: +44 (0)1905 794795, Fax: +44 (0)1905 794002.