ALPA extend their polyurethane range24 April 2002
ALPA SpA, the Italian leather chemical manufacturers, have extended their range of polyurethane based finishing compounds. RPU K 040 is an aliphatic polyurethane aqueous dispersion, with cationic charge, to form a thin, elastic film with good physical resistance and very good adhesion. Finished leathers using RPU K 040 are characterised by extreme naturalness, uniformity and a pleasant touch. RPU K 040 improves leather absorption regularity without grain loading and is also recommended as an anchoring agent for leather with difficult penetration and adhesion problems. RPU K 040 is particularly used for finished nappa articles. It can be used in cationic mixtures as polishable or plated ground coats and in covering solutions. With its particular grafting properties, RPU K 040 is suitable as a first coat for leather with adhesion problems during the finishing process. This product has a solids content of 20% and a pH of 4.0 in a 10% solution. Akral PU 18 is a modern compound for finishing buffed upholstery leathers (wet-toggled, usually filled with stucco and strongly buffed). Thanks to its accurate formulation and selection of quality raw materials, good quality furniture leather can be obtained, even with second-rate crust. With Akral PU 18, there are no problems with cutting at the embossing stage: after dry milling, the leather is soft with a uniform pattern. The finished leather has a natural look, not made heavy by the finishing, and with good general physical resistance. Using a compound such as Akral PU 18 assures consistency during production, storage, weighing and a wide range of articles and applications. Akral PU 18 is used for upholstery, on normal wet-toggled leather, filled with stucco and well polished and buffed. The following mixture should be sprayed with a mixture of an airless or HVLP system at a rate of 13-15g/sq in: * 100/150 Pigment * 600/700 Akral PU 18 The viscosity should be adjusted depending on the type of leather and application with SFT TV 130 thickener: in general, viscosity should vary between 30-40 inches (Ford cup No.4). Apply a coat of aqueous nitroemulsion type NEA (1:1 in water), emboss, dry mill for 12 hours and respray with one or two coats of the following solution: * 800 Mix ground * 100 Water * 50 Dowanol PM * 50 Akral RF 916 Fix with the usual aqueous fixative and dry mill lightly if necessary, then stake. Pass to the reverse roller coater, dry, spray on a smoothing coat, dry, apply a coat of aqueous nitroemulsion and dry. Press and continue as suggested for the first application. This product has a solids content of 30% and a pH of 8.3 in a 10% solution. Prefondal D57 is a polishable compound that is used as a ground coat to obtain a sealing level with an unloaded grain and a natural aspect. Leathers using Prefondal D57, after polishing and/or ironing, look shiny and are soft to touch with a very mild grain. Prefondal D57, added during intermediary coats, operates well as an agent and covers with a softening action. It can be used alone or added with a dye and/or pigment, depending on the article. Prefondal D57 is perfectly compatible with anionic and non-ionic ALPA auxiliaries. It can be added in successive finishing stages to increase the level of covering and maintain its natural characteristics. This product has a solids content of 20% and a pH of 9.0 in a 10% solution. Prefondal K 53 develops a softening and lubricating action on the grain leather. It works as an absorption regulator, whether on full grain or snuffed. Leathers treated with Prefondal K 53, during the first stages of finishing, are characterised by high reactivity, a soft touch and are exempt of grey effect from blind grey. Prefondal K 53 is compatible with ALPA cationic binders and can be added to anionic ALPA ground coats to increase their sealing properties, without crust colour modification. They prepare as well as support the leather for the successive finishing stages. This product has a solids content of 50% and a pH of 5.0 in a 10% solution. NEA 212 is a clear water nitroemulsion giving a medium soft, glossy film with a natural slippy touch. Finished leathers made with NEA 212 have a good ironability and embossing properties, strong fastness and good water swelling resistance. Most noticeable is its high flash point, over 100°C. For this reason, it is considered as a non-flammable chemical and is easier to stock and transport. NEA 212 is recommended as a main component for final water base fixatives. The suggested optimal dilution can vary as: * 500-600 NEA 212 * 500-400 Water To reach highest physical fastness, NEA 212 can be used in combination with APLA fixatives top coats and added with touch agents as: * 400 NEA 212 * 340 Water * 100 Alpatop F90 Matt * 150 Alpatop F91 * 5/10 Aplaret * 5 SFT F 2009 * 1 SFT S 160 This product has a solids content of 17% and a pH of 7.5 in a 10% solution.