| 摘要 |
Aq. compsns. for pretanning unhaired hides or retanning leather comprise a 2-8C aliphatic dialdehyde (I), an anionic aromatic tanning agent (II), water and opt. an acid. Also claimed is a pre- or retanning process in which an unhaired and bated hide or pretanned leather is contacted with an aq. bath contg. the above components. Pref. (I) is glutaraldehyde. (II) is a condensn. prod. of (a) HCHO and a sulphonated phenol or cresol, (b) HCHO and naphthalene sulphonic acid, (c) HCHO, di(4-hydroxyphenyl) sulphone and a (hydroxy)aryl sulphonic acid, (d) HCHO, a sulphonated aromatic OH cpd. and an aralkyl halide, (e) HCHO, phenol and phenol sulphonic acid, (f) phenol and a sulphonating agent in a phenol:SO3 molar ratio of 1:1.1-2.2, (g) HCHO and a sulphonated diaryl ether, (h) HCHO and a sulphonated bi- or terphenyl, (h) HCHO, di(4-hydroxyphenyl) sulphone and sulphonated di(4-hydroxyphenyl) sulphone, (i) HCHO, a diaryl ether sulphonic acid and di(4-hydroxyphenyl) sulphone, or (j) HCHO, phenol and a (hydroxy)aryl sulphonic acid. The compsns. contain 2-20% (I), 20-55% (II) and sufficient acid to give a pH of 1-6.5. The (I):(II) wt. ratio is 5:95 to 95:5. Pre- or retanning is effected at 15-45 degrees C and pH 1-6.5 for 1-12 hr.. |
