| 摘要 |
H3PO4 opt. mixed with another inorg. acid, pref. H2SO4, is used as acid in tanning leather, e.g. of ox, horse, pig, sheep, goat or calf, by pickling a limed, unhaired hide in an aq. soln. of an acid, followed by Cr-tanning. Pref. acid concn. in pickling step is 0.1-7 (1.5-3) wt. %/wt. hide. Wt. of H3PO4 refers to aq. soln. having specific wt. 1.75. Wt. of other acids refers to 100% concn. Wt. ratio H3PO4 : other acid is 1 : 10 to 10 : 1 (1 : 4 to 5 : 1) esp. 1 : 3 to 3 : 1. Tanned prods. having smoother grain can be obtd. by adding 4-8 wt. % inorg. salt, esp. NaCl, to pickling fluid. |
