Wet-end products from Lowenstein

American leather chemicals manufacturer, Jos H Lowenstein & Sons Inc have launched three new products for wet-end leather processing. They include a cationic sandwich dye, a retanning polymer and a synthetic fatliquor. Lowatan SD liq: A cationic sandwich dyeing auxiliary which provides the leather with good build-up properties and can be used on all leather types. Lowatan SD liq is available in all shades and has good lightfastness and heat resistance properties. It is based on an addition compound of a polyquartenary amine with an ethylene oxide. This product has a good stability to electrolytes and is ideal for sandwich dyeing with anionic dyes. Lowatan SD liquid's affinity with the substrate reverses the surface charge of the leather allowing it to become more cationic providing a top dyeing with a deeper, more brilliant shade. The cationic nature improves fixation of anionic dyes at a low pH and dye migration is prevented if a final washing is completed after dyeing. Lowenstein recommend a 0.5 -2.0% offer on shaved weight to be applied prior to the top dyeing (second dye-feed) in a sandwich system. Add in a 1:4 ratio with water at 60°C while stirring. Lowatan SN: A polymeric resin suitable for retanning suede and nubuck leathers. The product is based on a melamine resin and provides the leather with good buffing properties and gives a nice, even nap. The anionic resin has good heat resistance and lightfastness and is typically added dry without dilution. Lowatan SN has excellent retanning and filling characteristics and penetrates deeply into the leather with little bleaching. It has been specifically designed for suede and nubuck but also has a strong filling effect on full grain and may be added to vegetable extracts. It is compatible with all conventional retanning agents, fatliquors, auxiliaries and dyes with an anionic charge. SN can be used on furniture upholstery and garment leathers. It is recommended to add 3-6% calculated on shaved weight or 1-2% when added as a dye leveller. Lowenol EML: A synthetic fatliquor made up of a blend of sulfated fatty alcohols and natural oil with special emulsifiers. The anionically charged product has very good lightfastness and heat resistance and should be added to water at 60°C in a ratio of 1:4. Lowenol EML is a general purpose fatliquor for all leather types. It produces a lightweight fluffy leather with a silky surface feel. It is suitable for light and pastel shades. This product is electrolyte stable and when applied in the pickle as a prefat, the softness and area yield of the leather is greatly improved. EML has a high emulsifying power and can, therefore, be applied for emulsifying raw oils. In a typical formulation Lowenstein recommend a 4% offer for shoe upper (based on shaved weight) and 2g/l for woolskins using a float ratio of 20:1. This product is stable in chrome tanning floats.