| 摘要 |
The process consists of (A) partial oxidn. of dextrin by treatment in aq. suspension with periodic acid, gentle heating neutralising with Na2CO3 and agitation until clarification; (B) de-pickling the skin by treatment with NaCl and Na2CO3 for 30 mins. approx.; (C) activating the skin with the partially-oxidised dextrin (15-25%) for 6 hours; (D) emptying the liq. and re-pickling by treatment with formic acid, followed by curing with titanium ammonium sulphate (25-32%) for 6 hours, standing overnight and neutralising next day with successive addns. (2% each time) of mixts. of urotropine and Na2SO3 (1:1) added at intervals of 1-1.5 hours, heating to 40-45 deg. C after the third addn.; and (E) opt. adjusting to pH 5-5.5 with Na2CO3 or NaHCO3.
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