Study on removal of salt from iron artifacts that came out of underground at histrical places by using alkaline solutions containing fluorinated oligomers

利用人工压制的锈铁圆盘，考察了碱性溶液中加入含氟低聚物对除盐效果的影响。结果表明，与实际使用的倍半碳酸盐溶液相比，在KOH溶液中加入含氟低聚物可提高除盐效果。此外，我们还发现甜菜碱型低聚物适合于去除盐分。为了找出哪种类型的甜菜碱更适合于这一目的，我们通过实验考察了含氟低聚物的除盐效果。含SK-6的KOH水溶液、含亲水基团的甜菜碱型低聚物和含氟长链的甜菜碱型低聚物的去盐量是倍半碳酸盐溶液的3.7倍。另一方面，发现了一种带有疏水基团的低聚物SK-15，它可以防止铁盘生锈。接下来，我们研究了低聚物对碱性…处理后的铁文物长期保存的影响更多含有甜菜碱型含氟低聚物的溶液。我们使用的是在我们的罗姆保存了14到18个月的试件。然后，将试件悬浮在一个100毫升的瓶子里，瓶底有水，保持在空气中以防止与水接触。之后，测量体重的变化。结果表明，与不加齐聚物的KOH溶液相比，倍半碳酸盐、SK-15、SK-2和SK-6的干重分别增加了5.9倍、2.5倍、2.2倍和1.3倍。结果发现，含氟低聚物碱性溶液除盐处理后短期内的再生锈会被甜菜碱型低聚物中的疏水基团抑制，而长期保存中的再生锈将取决于铁制品中残留的盐量。因此，SK-6被认为是一种合适的碱液除盐添加剂，因为在我们的实验中，SK-6的加入最能改善盐分的去除。较少

Using rusted iron disks pressed artificially, effects of fluorinated oligomers added to alkaline solutions on removal of salt were investigated. As a result, addition of fluorinated oligomer to KOH solution was found to bring improvement on removal of salt compared with the sesquicarbonate solution that have been applied in practice. Also, we found that betaine-type oligomers are adapted for removal of salt. To find which type of betaine is adequate for this purpose, we investigated the effects of fluorinated oligomers on removal of salt experimetally.Amount of salt removed for KOH aqueous solution containing SK-6, betaine-type oligomer with hydrophilic group and long chains of fluorinated group, increased 3.7 times as much as that for the sesquicarbonate solution. On the other hand, an oligomer, SK-15, with hydrophobic group was found to prevent the iron disk from rusting.Next, we investigated the effects of the oligomers on long-term conservation of iron artifacts treated by alkaline … More solutions containing betaine-type fluorinated oligomers. We used test pieces which had been kept in our romm for 14 to 18 months. Then, the test piece was suspended in a 100 mL bottle with water on the bottom, which was kept in air to prevent from contacting with water. After that, change in weight was measured. From the results, we found that increments of dry weight of the test pieces were 5.9 times for sesquicarbonate, 2.5 times for SK-15, 2.2 times for SK-2, 1.3 times for SK-6 compared to that for KOH solution without oligomers. The increment in weight due to re-rusting decreased with increasing the amount of salt removed.Consequently, we found that re-rusting in a short period after removal treatment of salt by alkaline solution containing fluorinated oligomer was suppressed by the hydrophobic group in the betaine-type oligomer, and re-rusting in long-term conservation will depend on the amount of salt remainted in the iron artifacts. Hence, the SK-6 is considered to be adequate as an additive to alkaline solution for removal of salt, because in our experiment addition of the SK-6 most improved the removal of salt. Less