| 摘要 |
<p>A polyurethane is prepared by the reaction of a stoichiometric excess of a di- or higher functional organic isocyanate with a mixture of one or more monohydric alcohols and one or more polyoxyalkylene polyols which contain more than two hydroxyl groups. The polyol is preferably a triol and preferably prepared from propylene oxide and a trihydric alcohol, e.g. glycerol, trimethanol propane, hexane triol. The monohydric alcohols may be represented by the formula R(OCnH2n)yOH where R is a hydrocarbon radical, n may be 2, 3 or 4, and y may be 0 or an integer between 1 and 50. Compounds mentioned are the condensation products of ethylene oxide with cetyl-oleyl alcohol and ethylene oxide with nonyl phenol. The isocyanate may be aromatic or aliphatic. The mixture of alcohols may also contain a polyoxyalkylene diol which may be the reaction product of propylene oxide with water or a dihydric alcohol, e.g. propylene glycol and preferably has a M.W. of 1000-3000. The polyurethane may be dissolved in a solvent, e.g. an ester, ketone or hydrocarbon fraction and used for coating leather. Up to 100% of raw oil, e.g. cold test neatsfoot oil or sperm oil may be incorporated in the solution. In Example (1) a mixture of glycerol based polyoxypropylene triol, cetyl-oleyl alcohol and polyoxypropylene diol were reacted with tolylene diisocyanate and the polymer dissolved in Shellsol "A." In other examples, the monohydric alcohols used were (1B) condensate of nonyl phenol and ethylene oxide, (1C) anhydrous butanol, (2) cetyl-oleyl alcohol, (11) a butoxy polyoxypropylene monohydric alcohol.ALSO:A solution of a polyurethane in an aromatic hydrocarbon fraction, ketone or carboxylic ester is applied to leather, said polyurethane having been prepared by reacting a mixture of one or more monohydric alcohols and one or more polyoxyalkylene polyols which contain more than two hydroxyl groups with a stoichiometric excess of a di or higher functional organic isocyanate. The urethane solution may be applied by a paint roller or by spraying or padding. Leathers mentioned are: shoe upper leather, full chrome goatskin, pigskin, sheepskin, upholstery and case leathers. In a typical example (II) a mixture of a polyoxypropylene triol and a butoxy polyoxypropylene monohydric alcohol were reacted with toluene diisocyanate in shellsol "A" and the polymer solution appled by spraying to the grain side of chrome upper shoe leather, the solvent allowed to evaporate and the treated leather finished by coating with a pigment and an acrylic resin emulsion followed by a spray coat of nitrocellulose emulsion and finally by a tinted spray coat of high flash nitrocellulose lacquer.</p> |
