| 摘要 |
<p>Leather, grain-layers are strengthened by impregnating the leather with water-soluble, polyfunctional methylol cpds., (I) in the presence of polar solvents, (II). The treated leathers are claimed. (I) may be (a) N-methylol derivs. of urea or its derivs. melamine, carbamates (correction; cf. claim-carbonates) or urones, esp. melamine-modified polyglycol acetals, and/or (b) polyalkylene glycol condensates with lower aldehydes, esp. HCHO, or (c) mixts. of (a) and (b) with thermoplastic resins. (I) may be glycols and polyglycols. The quantity of (I) applied, calculated as solids, is 10-100 (15-60) esp. 20-40 g/m2. The mixts. may contain 5-45% (I), 5-25 (8-15)% glycol, opt. 0.5-2 (0.8-1.5)% amphoteric emulsifier, balance water to 100%. The mixts. are stable and resist storage. The compsns. can penetrate trough finely structured surface, even in fully grained leathers, to reach and strengthen the bottom grain layer. The finished layers can be glazed.</p> |
