摘要
本文研究了四种典型天然不饱和油脂的结构对氧化深度的影响。加入催化剂强制深度氧化天然不饱和油脂，通过测定氧化后油脂的氢过氧化值（PV），控制氧化油脂的活性。实验结果表明：鱼油虽然具有很高的碘值，但由于其含有较多的孤立双键，在氧化时会转变为共轭双键而树脂化，因此其PV极值只有380mmol／kg。茶油、菜油和豆油的双键类型主要是隔离双键，具有较高的活性。豆油所含的隔离双键最多，其次是菜油，茶油中隔离双键的含量最少，因此它们PV极值分别为：豆油1568mmol／kg，菜油995mmol／kg，茶油870mmol／kg。这说明油脂的碘值不是油脂氧化深度的唯一影响因素，脂链上双键的构型以及位置也有很大的影响。
从油鞣工艺角度出发，系统的研究了pH、时间、温度、油脂PV值和用量等条件的改变对油鞣浸酸兔皮后收缩温度的影响。实验结果表明，无论油脂的碘值如何、是否氧化以及氧化的深度如何，鞣制浸酸兔皮后收缩温度有所提高，但始终低于浸酸前裸皮的收缩温度。水洗后，与浸酸前裸皮的收缩温度相似。说明在本实验工艺条件下，油脂或氧化油脂在鞣制过程中没有鞣制作用。油脂或氧化油脂用于处理甲醛预鞣革，其收缩温度也没有明显的变化，但是其抗张强度和伸长率等物理力学性能得到了一定的改善。在本实验中，表明油脂的作用是润滑纤维，即实际起加脂剂的作用。油脂在油鞣过程中的作用与传统油鞣观点有明显的不同。
为了减少甲醛对环境带来的负面影响，采用氨基树脂代替甲醛进行预鞣。研究了PH、用量、时间、温度等因素对氨基树脂鞣制的影响。结果表明：氨基树脂在酸性条件下没有鞣性，收缩温度低于浸酸前裸皮收缩温度；在碱性条件下，氨基树脂与皮胶原活性基发生化学交联，PH为8时，革的收缩温度即可达到80℃以上；随着用量的增加，革的收缩温度随之升高，但用量超过10％后，收缩温度的升高不明显；鞣制20分钟后，氨基树脂与皮胶原活性基的结合基本完成，延长时间，革的收缩温度不再升高；鞣制温度对革的收缩温度基本无影响。加入鱼油对氨基树脂鞣革进行处理，结果表明革的收缩温度没有明显的提高，但是柔软性、抗张强度和伸长率均有改善。无论是从收缩温度还是物理力学性能考察，氨基树脂都能取代甲醛进行预鞣。
The influence of the structure of four kinds of natural unsaturated oil on the oxidation depth was studied. Catalyzer wasadded to oxidize natural unsaturated oil. The Peroxide value was tested to control the activity of oxidized oil. The results showed：although the iodine value of fish oil was high, the insular double bonds were transformed into conjugated double bonds, which wouldmade fish oil resinoid. The maximal peroxide value of fish oil was 380 mmol/kg. The type of double bonds in tea oil rape oil and bean oil was isolated double bond, which was highly active. The content of isolated double bond in bean oil was more than that in rape oil and tea oil. The maximal peroxide value of bean oil, rape oil and tea oil was 1568 mmol/kg, 995 mmol/kg, 870 mmol/kg, respectively. That meant the iodine value of oil was not the exclusive factor influencing the oxidation of oil, the configuration and position of double bond played certain role.
The influence of tanning pH, time, temperature, peroxide value and dosage on the shrinkage temperature of pickled rabbit skin was researched. The results showed; The Ts of oil tanned pickled skin increased to certain extent, but was lower than that of fresh skin. After washing, the Ts of oil tanned pickled skin was equal to that of fresh skin. It meant oil or oxidized oil didn＇ t display tanning property in the experiment mentioned in the essay. Treated with oil or oxidized oil, the Ts of formaldehyde tanned leather didn＇t change, but the tension strength and elongation were improved, which showed oil lubricated leather fibers in the process. The role of oil in oil tanning was different from the views of traditional oil tanning.
To decrease the negative effect of formaldehyde on environment, amino resin was chose to displace formaldehyde. The influence of tanning pH, time, temperature, peroxide value and dosage on the tanning property of amino resin was researched. The results showed; amino acid didn＇t display tanning property in acid. When pH was eight, the shrinkage temperature could reach to 80℃ or above. The shrinkage temperature rose with the increase of dosage. If the dosage was more than 10% of the weight of skin, the rise of shrinkage temperature was not evident. The tanning finished in 20 minutes. The tanning temperature had nothing to do with the shrinkage temperature. The physical properties of amino resin tanned leather treated by fish oil was better than that of formaldehyde tanned leather treated leather, so formaldehyde could be displaced by amino resin.
关键词
油鞣
鞣制
不饱和油脂
氧化
氨基树脂
oil tanning tanning unsaturated oil oxidation amino resin
