落叶松栲胶高度亚硫酸化改性及其产物应用性质的研究

落叶松栲胶经过高度亚硫酸化反应，小分子部分增多，产物平均分子量降低，Ｎａ２ＳＯ３ 和ＮａＨＳＯ３ 总用量为３０ ％ 时，分子量低于７１３ 的组分由３０ ％ 增加到６０ ％ ，其分布变得更均匀，色度值、粘度值、盐析值均下降，耐酸性增强，用于制革时，渗透速率增加，具有比传统方法生产的栲胶更优良的结合鞣、复鞣及填充性能。

MODIFICATION OF LARCH BARK TANNIN EXTRACT BY INTENSIVE SULFITATION

This research refers to comprehensive improvement of tanning properties of larch bark tannin extract.Intensive sulfitation was adopted so that the product has faster penetration into pelt and relatively moderate astringency,which is the requirement of modern leather making.Degradation of tannin was increased with the increase of sulfite dosage.When 30 % sulfite was used,the components with molecular weight lower than 710 increased to 60 % of the extract,doulbed in comparison with the original tannin extract.As a result the product having lower average molecular weight,reduced viscosity,lighter color and better salt out and acid endurable ability was obtained.Used in combination tannages,or as retanning agent,the performances of the modified product were obviously improved.