【作者】 孙丹红；

【导师】 石碧；

【作者基本信息】 四川大学 ， 皮革化学与工程， 2003， 博士

【摘要】 制革工业是我国具有综合优势的传统产业。但是，中国制革工业的持续发展正面临着环境污染、资源利用率低、生产效率低的严峻挑战。因此用高新技术改造这一传统产业，实现制革工业的绿色化和高新技术化具有重大的现实意义。 本文系统研究了超声波的空化效应对除去皮纤维问质和分散胶原纤维的作用；研究了超声波对制革常用酶制剂、鞣剂、染料和加脂剂在裸皮和皮革中的渗透速率、分布均匀性及吸收率的强化作用；同时还系统研究了超声波对含铬废革屑氧化脱铬的促进作用。 超声波对生皮作用的研究表明，超声波可以促使裸皮中可溶性蛋白质的溶解，有助于除去生皮中的纤维间质，且不损害裸皮的胶原纤维结构。同时超声波的空化效应使脂肪细胞壁破碎，油脂外溢，因此对生皮有脱脂作用。 超声波对制革常用酶制剂作用的研究表明，超声波对酶活力的影响因温度的变化而引起，因此在制革过程中超声波的使用不会影响酶的活力。 超声波对铬鞣、钛鞣和植鞣的影响研究表明，鞣剂的分子结构在超声波作用的过程中并未发生显著改变，因此鞣剂与裸皮的结合方式也未改变。超声波在溶液中的空化效应对鞣剂分子只具有分散作用，即鞣剂分子在超声波的空化效应作用下，四川大学博士论文得到进一步分散，更容易渗透到革内，所以在靴制初期有超声波作用时稣剂向裸皮内渗透较快，收缩温度提高也快，而在蹂制后期革收缩温度的差异逐渐减小。 超声波预处理染料溶液，可提高染料的扩散系数值，加快上染速率;提高 上染百分率，降低皮革染色废液中的染料含量。研究表明超声波预处理染液的 助染效果与染浴温度有关。在45℃下染色时超声波的作用更明显，染料的扩散系 数或上染百分率均显著提高，说明应用超声波可实现低于常规工艺温度条件的染 色，这样，既可减少能源消耗，又能节约染料，降低生产成本。 无论是先将加脂剂施加超声波进行预处理，或在加脂过程中施加超声波， 还是先将加脂剂施加超声波进行预处理再在加脂过程中施加超声波，超声波只 起到了进一步分散加脂剂的乳液颗粒，从而促进加脂剂的渗透的作用。 本研究还表明，超声波在皮革加工过程中的传播受皮张厚度的影响，一般超 声波不易透过皮革而传播。因此超声波在制革加工中的应用应限于处理的材料， 使材料进一步分散，有助于材料向皮内的渗透。 超声波作用下的氧化脱铬明显优于无超声波作用条件下的氧化脱铬，超声 波的作用时间、频率、声强和传声媒介等都会影响含铬废革屑的脱铬率。氧化 脱铬过程可能发生了交联反应，即自由基反应和醛一胺缩合反应。这种方法克 服了单纯的氧化法脱铬率不高的缺点，具有很好的应用前景。对含铬废革屑在 超声波作用下的氧化脱铬产物的分析表明，其氨基酸组成与生皮相比基本不变。 从形态学观察说明，脱铬产物的纤维性状与生皮胶原纤维相比基本相同。更多还原

【Abstract】 As a dominant traditional manufacture, leather-making industry in China is faced with counteraction of environment pollution, and low efficiency of processing and source utilization. Therefore, it is imminent to adopt advanced technologies to rebuild leather production and make it environment-friendly and sustainable development.The basic functions of ultrasonic waves on leather-making were systematically investigated in this thesis, which include the effect of ultrasound on the removal of soluble matters in pelt and opening-up of collagen fibers, and the influence of cavition on the dispersion, penetration and adsorption rate of leather chemicals (enzymes, tanning agents, dyestuffs and fatliqours). The effect of ultrasound on enhancing oxidative chrome removal of leather shavings was also studied.It was found that ultrasound is helpful to remove soluble proteins of pelt without damage of collagen fibers. Meanwhile, the break of fat cellular wall was observed under ultrasound, which accelerates the degreasing process.The effect of ultrasonic cavition on enzyme activity was inconsiderable, but the riseof solution temperature due to ultrasound could influence the activity of enzymes. So a proper control of temperature is important if ultrasound is used in the processes of enzyme treatment.The experiments showed that ultrasound can promote the penetration of chrome tanning agent, vegetable tannins and titanium tanning agent in pelt at the beginning of tanning, but at the end of tanning, the difference of shrinkage temperature of leathers with and without ultrasound is not remarkable. A further investigation indicated that the molecular structures of the tanning agents had not been changed under ultrasound and therefore, their combination modes with collagen are not altered. These proved that the only function of ultrasound in tanning processes is to increase the dispersion degree of tanning agents and accelerate their penetration rate in pelt.The effect of ultrasound at different frequencies on leather dyeing was studied. The factors influencing dyeing rate and dyestuff adsorption rate, such as sonication time and dyeing temperature, were investigated. The results showed that, for acid dyestuff, power ultrasound (23.7kHz) can considerably increase dyeing rate and the adsorption rate of dyestuff, but that of 17kHz showed no remarkable influence. It was found that the adsorption rate of dyestuff at 45 癈 was increased to 99.24%-99.75% after treating the dyestuff solution with power ultrasound for 20-30min. For direct dyestuff, the power ultrasound (23.7kHz or 17kHz) is not able to increase dyeing rate and absorption rate of dyestuff.The influence of ultrasound on fatliquoring was also studied. Considerable change was observed in the early stage of fatliquoring process when ultrasound was used,showing faster penetration of fatliquor. As a result, ultrasound remarkably accelerates fatliquoring process.The oxidation dechroming of leather shavings using hydrogen peroxide under ultrasound was studied. I was showed that the chrome removal rate of the shavings was influenced by reaction time, temperature, medium and intensity of ultrasound. When 20kHz and 40kHz ultrasounds were employed, the intensity of ultrasound should be regulated to 7-8W/cm2. The proper circumstance for ultrasonic oxidation dechroming was 20癈 and pH=9.0-10.0 adjusted by CaO. In these conditions, dechromed with 10% hydrogen peroxide (cone. 30%) under ultrasound for 8 times, a chrome removal rate of 99.46% was achieved, which is remarkably higher than 89.6%, the chrome removal rate using conventional method of oxidation dechroming.更多还原