The effects of ultrasound (38 kHz, 1.3 W cm-2) on the dyeing, fatliquoring and tanning of leather have been investigated and the mechanisms whereby ultrasound influences these processes were elucidated.;Compared with a conventional process, ultrasonic dyeing can either shorten the dyeing time by 40-70% or facilitate low temperature dyeing. This remarkable enhancing effect has been attributed mainly to an increased diffusion coefficient (D) of dyestuff in the presence of ultrasound. It was found that sonication is more effective in the initial phases than in the late phases of the dyeing process.;Application of ultrasound during the fatliquoring process or simply in the preparation of fatliquors resulted in an increase of leather fat contents (up to 40%), especially in the inner corium layer, indicating an improved penetration. This can be partly attributed to a reduction of particle size by 20-30%. In contrast to dyeing, ultrasound was found to be more effective later rather than earlier in the fatliquoring process.;Chromium and aldehyde tanning processes were accelerated only marginally (∼10%) but the mimosa tanning process was speeded up significantly (by up to 100%) by using ultrasound. Leathers tanned in the presence of ultrasound had shrinkage temperatures 3-5°C higher than conventionally processed controls. A more even chromium distribution and less chromium leaching were obtained after using ultrasound. The results showed that ultrasound can increase the dispersion rate and the available tannin content (by 7%) of mimosa, as well as reducing its particle size by 50%. It was also found that ultrasonic treatment can prevent mould from growing on mimosa tanned leathers.;It is concluded that ultrasound is more effective in a process which involves a colloidal rather than a true solution system. The prevailing effects of ultrasound on the former processes are to increase the diffusion coefficient and reduce the aggregation. This is due to cavitation..
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机译：研究了超声波（38 kHz，1.3 W cm-2）对皮革的染色，加脂和鞣制的影响，并阐明了超声波对这些过程的影响机理。与常规方法相比，超声染色可以缩短皮革的染色时间。染色时间减少40-70％或便于低温染色。这种显着的增强作用主要归因于在超声波存在下染料扩散系数（D）的增加。已发现超声处理在染色的初始阶段比后期更有效。;在加脂过程中或仅在制备加脂剂中使用超声波会导致皮革脂肪含量增加（最高40％ ），特别是在内层的皮质中，表明渗透性有所提高。这可以部分归因于粒度减小了20-30％。与染色相反，在加脂过程中，发现超声波比后期更有效，而不是更早。；铬和醛鞣制过程仅略微加速（约10％），但含羞草鞣制过程显着加快（高达100％） ）。在超声作用下鞣制的皮革的收缩温度比常规处理的对照高3-5°C。使用超声波后，可获得更均匀的铬分布和更少的铬浸出。结果表明，超声可以提高含羞草的分散率和有效单宁含量（7％），并将其粒径减小50％。还发现超声处理可以防止霉菌在含羞草鞣制的皮革上生长。结论：超声在涉及胶体而非真正溶液系统的过程中更有效。超声波对先前过程的主要影响是增加扩散系数并减少聚集。这是由于气蚀。
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