| 摘要 |
Disclosed is a leather tanning process comprising the steps of: A) - preparing a tanning initial liquid of tanning agent made of poly hydroxyl alkyl phosphine and its derivatives then adding a stabilizer to the tanning initial liquid; said stabilizer is a mixture that contains surface active agent, poly hydroxyl compound, phosphate salt, preservatives in an amount of 0.1-2 percent of pickling skin weight or 0.1-3 gram/liter of tanning bath liquid; adding a buffer agent to the tanning initial liquid in an amount of 0.1-3 percent of pickling skin weight and 0.1-3 gram/liter of tanning bath liquid; wherein the tanning initial liquid contains at least one type of poly hydroxyl alkyl phosphine and its derivatives in a concentration of 0.4-5.0 percent of pickling skin weight, preferably 1.0-5.0 percent of pickling skin weight, or 0.4-7 gram/liter of tanning bath liquid, preferably 1-7 gram/liter oftanning bath liquid; and B) - adding the pickling skin to the tanning initial liquid, the skin being rotated 90-360 degrees, and adding alkali successively to increase the pH of the bath liquid gradually to 5-7, the skin being again rotated 60-360 degrees and taken out, after tanning is completed, washing the skin with water, and performing the routine post-tanning step, the concentration of the poly hydroxyl alkyl phosphine and its derivatives in the residual liquid being measured through iodine titration solution by using micro titration test chamber, analyzed and adjusted to the initial tanning agent content, and adjusting the pH with acidic matters between 3-5; and C) adding 0-50 percent of the stabilizer and the buffer agent in step A) to the aforesaid adjusted tanning bath liquid, the residual liquid of the completely adjusted mixture of tanning agent stabilizer and buffer agent being recycling batch wise or continuously.
|
