JP4552295B2

JP4552295B2 - Preservation method of water-immersed organic artifacts.

Info

Publication number: JP4552295B2
Application number: JP2000268054A
Authority: JP
Inventors: 和典進士; 宏行河野; 康二湧口
Original assignee: Mitsubishi Chemical Corp
Current assignee: Mitsubishi Chemical Corp
Priority date: 2000-09-05
Filing date: 2000-09-05
Publication date: 2010-09-29
Anticipated expiration: 2020-09-05
Also published as: JP2002079503A

Description

【０００１】
【発明の属する技術分野】
本発明は、遺跡から出土した水浸有機遺物の保存処理方法に関するものである。
【０００２】
【従来の技術】
遺跡から発掘される水浸有機遺物、特に木材は腐朽かつ吸水しており、その主成分であるセルロースやヘミセルロースを構成する多糖類が、微生物によって分解され弱くなっている。このため、これらの脆くなった水浸有機遺物をそのまま乾燥させると著しく収縮し、変形や破壊が生じ文化財としての価値を失ってしまう。
【０００３】
そこで、木材中に進入した過剰な水分を除去し、分解や破壊された細胞を強化する方法として、従来、水溶性の高分子材料たとえばポリエチレングリコール、蔗糖又はラクチトール等の水溶液に水浸有機遺物を含浸させて強化させる方法等が行われている。
【０００４】
【発明が解決しようとする課題】
従来のポリエチレングリコールを含浸させる方法では、長期間の加熱が必要であり、また、高分子の分解により水浸有機遺物が劣化すること、水浸有機遺物の内部まで十分に浸透しないなどの欠点がある。
【０００５】
蔗糖を含浸させる方法は、脆くなっている水浸有機遺物を十分に強化できないうえ、処理中に分解して褐色変化を起こす欠点を有す。また、この方法で処理された水浸有機遺物は高湿度の環境では蔗糖が溶解したり、生物による分解のおそれがある等の欠点がある。
【０００６】
これら上記のいずれの方法も、処理に年単位の長期間を要し、大規模な設備が必要で、経費が嵩んでいた。
【０００７】
最近になり開発されたラクチトール、マルチトール等の糖アルコールを含浸させる方法（例えば、「考古学と自然科学第２８号、１９９３、ｐ．７７−９５．」、特開平８−５７８１２号等）は、水浸有機遺物の処理期間がそれまでの方法と比較すると短く好ましい方法であり、実際にラクチトールは水浸有機遺物の処理に使用されている。しかしながら、上記公報にはエリスリトールに関する具体的記述はない。また、処理期間が短いため実用化されているラクチトールを使用する方法は、含浸処理後に結晶化を促進させるためにラクチトール１水和物の微粉末を添加する必要があること、ラクチトール３水和物結晶の生成を防止するために５０℃で数日間乾燥させる必要がある等の欠点があるため充分満足できる方法ではない。
【０００８】
本発明は上記の従来技術の欠点を改善することを目的とするものであり、以下の利点を有する水浸有機遺物の保存処理方法を提供する。１）ポリエチレングリコールはもとよりラクチトールよりも浸透性が高く、結晶性に優れ、且つ結晶水を持たないことから、処理に要する時間、エネルギーを削減できる。２）ラクチトールよりも更に非吸湿性であり、微生物による分解もないことから、高温多湿の環境下においても水浸有機遺物が腐朽しない。３）処理後の水浸有機遺物にひずみがみられない。
【０００９】
【課題を解決するための手段】
本発明は、水浸有機遺物をエリスリトール水溶液中に浸漬し、水溶液の温度を徐々に上昇させながら水分を飛ばすことによって濃度を上げ、エリスリトールを水浸有機遺物に含浸させ、その後水浸有機遺物を水溶液より取り出して乾燥させることよりなる水浸有機遺物の保存処理方法である。
【００１０】
本発明では、エリスリトールを水に溶かすことによってエリスリトール水溶液を調製する。エリスリトール水溶液は、始め温度を２０〜６０℃、好ましくは４０〜６０℃とし、濃度を３０〜６０％、好ましくは４０〜６０％に調製し、水浸有機遺物を浸漬する。温度を徐々に上昇させ、最終的には６０〜８０℃、好ましくは８０℃とし、濃度は６０〜７５％、好ましくは７５％に調製する。エリスリトール水溶液が水浸有機遺物へ含浸したかどうかは、水浸有機遺物の浮き沈みで判断する。完全に含浸すると水浸有機遺物は沈む。
【００１１】
含浸終了後、３０〜６０℃のお湯で水浸有機遺物の表面を洗浄し、室温で恒量となるまで乾燥させることにより、エリスリトールを結晶化させる。もしくは、含浸終了後室温で乾燥させ結晶化させた後、３０〜６０℃のお湯で表面の結晶を洗浄し、再び室温で恒量となるまで乾燥させ、エリスリトールを結晶化させることにより水浸有機遺物の保存処理は完了する。
【００１２】
【実施例】
以下、本発明の実施例と比較例を示し、本発明を更に具体的に説明するが、本発明はこれらの実施例に限定されるものではない。尚、実施例及び比較例で使用した水浸有機遺物は含水率（吸水している水の重さ÷乾燥重量×１００）約９９０％で、全ての例でほぼ同じ大きさ（直径５ｃｍ、幅２．５ｃｍ）のものを用いた。
【００１３】
実施例１
（１）蓋付きの５Ｌステンレス缶に、４０℃、４０％のエリスリトール水溶液３．２ｋｇを入れ、水浸有機遺物（図１の左）を浸漬した。温度調整は、ウィンディーオーブン内で行った。
（２）水浸有機遺物が沈んだら、ステンレス缶の蓋をはずして水分を蒸発させ、エリスリトールの濃度上昇を徐々に行った。濃度の上昇に伴い温度も徐々に上昇させ、最終的に８０℃にまで温度を上げ、エリスリトール濃度を７５％まで上昇させた。
（３）７５％エリスリトール水溶液が水浸有機遺物に完全に含浸し、水浸有機遺物が沈むまで１４日間を要した。含浸処理終了後、５０℃のお湯で表面の糖液を洗浄し、室温放置することにより結晶化させ、恒量になるまで１０日間を要した。
（４）全処理（２４日間）を終えた水浸有機遺物（図２の左）にひずみは見られなかった。
【００１４】
実施例２
（１）実施例１と同様の方法で、エリスリトールを水浸有機遺物（図１の右）に含浸させた。
（２）含浸処理終了後、２日間室温乾燥して結晶化させた。結晶化した水浸有機遺物の表面上の結晶を５０℃のお湯で洗浄し、恒量になるまで６日間室温乾燥させた。
（３）全処理（２２日間）を終えた水浸有機遺物（図２の右）にひずみは見られなかった。
【００１５】
実施例１及び実施例２のフローチャートを表１に示した。
【００１６】
【表１】

【００１７】
実施例３
（１）蓋付きの５Ｌステンレス缶に、５５℃、５０％のエリスリトール水溶液３．２ｋｇを入れ、水浸有機遺物を浸漬した。温度調整は、ウィンディーオーブン内で行った。
（２）一日後、水浸有機遺物内に５０％エリスリトール水溶液が充分に含浸し、サンプルが沈んだ。
（３）ステンレス缶の蓋をはずして水分を蒸発させ、エリスリトールの濃度上昇を行い、濃度の上昇に伴い温度も徐々に上昇させた。
（４）最終的に８０℃にまで温度を上げ、エリスリトール濃度を７５％まで上昇させるのに７日間を要した。
（５）含浸処理終了後、実施例１又は実施例２と同様の方法で洗浄、乾燥、結晶化させた。
（６）初期濃度を高めかつ濃度上昇を速めても、実施例１又は実施例２と同様、全処理（１６〜１８日間）を終えた水浸有機遺物にひずみは見られなかった。
【００１８】
比較例１
（１）蓋付き５Ｌステンレス缶に、４０℃、４０％のラクチトール水溶液３．２ｋｇを入れ、水浸有機遺物を浸漬した。温度調整はウィンディーオーブン内で行った。
（２）ラクチトールが水浸有機遺物内部まで浸透したかどうかは、水浸有機遺物の浮き沈みで判断する。水浸有機遺物が沈んだら、ステンレス缶の蓋をはずして水分を蒸発させ、ラクチトールの濃度上昇を徐々に行った。濃度の上昇に伴い、温度も徐々に上昇させた。水浸有機遺物が浮上したら蓋を閉め、濃度上昇を停止させた。この操作を繰り返し、８０℃にまで温度を上げ、最終的にラクチトール濃度を８５％まで上昇させた。
（３）８５％ラクチトール水溶液が水浸有機遺物に完全に含浸し、水浸有機遺物が沈むまで２９日間を要した。含浸処理終了後、５０℃のお湯で表面の糖液を洗浄し、ラクチトール１水和物の微粉をまぶし、２日間５０℃で乾燥し、結晶化させた。ついで、５０℃のお湯で水浸有機遺物表面の結晶を洗浄し、５０℃で恒量になるまで２日間乾燥させた。
（４）全処理（３３日間）を終えた水浸有機遺物にひずみは見られなかった。
【００１９】
比較例２
（１）比較例１と同様の方法で、ラクチトールを水浸有機遺物に含浸させた。
（２）含浸終了後、ラクチトール１水和物の微粉をまぶし、２日間５０℃で乾燥し、結晶化させた。ついで、５０℃のお湯で、乾燥させた水浸有機遺物表面の結晶を洗浄し、５０℃で恒量になるまで２日間乾燥させた。
（３）全処理（３３日間）を終えた水浸有機遺物にひずみは見られなかった。
【００２０】
比較例１及び比較例２のフローチャートを表２に示した。
【００２１】
【表２】

【００２２】
従来法で最も優れたラクチトール法とエリスリトールを用いた本発明を比較した結果を表３に示す。
【００２３】
【表３】

【００２４】
処理期間の短さや有機遺物の強化の点で現在もっとも優れているラクチトール法と比較すると、含浸処理に要する日数は約二分の一であった。また、エリスリトール水溶液の初期濃度、温度をそれぞれ５０％、５５℃とし、濃度上昇を速めることにより含浸処理期間をラクチトール法の約四分の一まで縮めることができた。ラクチトール法では、結晶化にラクチトール１水和物の結晶粉末の添加が必要であるが、本発明では不要であり、粘度の低さや結晶の剥がれ易さも加味すると、ラクチトール法よりも操作が簡便であり、優れている。水浸有機遺物の強化も十分であり、吸湿性はラクチトールよりも低い。
【００２５】
【発明の効果】
本発明に係る水浸有機遺物の保存処理方法は、エリスリトールの浸透性が高く、結晶性にも優れていることから、処理に要する時間、エネルギーを大幅に削減できた。さらには、吸湿性も低く、非腐朽性、防蟻性、熱安定性、寸法安定性にも優れたものである。
【図面の簡単な説明】
【図１】処理前の水浸有機遺物（左：実施例１、右：実施例２）
【図２】エリスリトール含浸処理後の水浸有機遺物（左：実施例１、右：実施例２）[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for preserving water-immersed organic artifacts excavated from a ruin.
[0002]
[Prior art]
The water-immersed organic artifacts excavated from the ruins, especially wood, are decayed and water-absorbed, and the polysaccharides that make up the main components of cellulose and hemicellulose are degraded and weakened by microorganisms. For this reason, if these water-immersed organic relics that have become brittle are dried as they are, they will shrink significantly, resulting in deformation and destruction, losing their value as cultural assets.
[0003]
Therefore, as a method of removing excess water that has entered the wood and strengthening the cells that have been decomposed or destroyed, conventionally, a water-soluble polymer material such as polyethylene glycol, sucrose, or lactitol is used as a water-immersed organic relic. A method of impregnating and strengthening is performed.
[0004]
[Problems to be solved by the invention]
The conventional method of impregnating with polyethylene glycol requires heating for a long period of time, and the degradation of the water-immersed organic relics due to the decomposition of the polymer, and the inadequate penetration of the water-immersed organic relics inside. is there.
[0005]
The method of impregnating sucrose does not sufficiently strengthen the water-damaged organic relics, and also has the disadvantage that it decomposes during processing and causes a brown color change. In addition, the water-immersed organic relics treated by this method have disadvantages such as sucrose being dissolved in a high humidity environment and possibly being decomposed by living organisms.
[0006]
In any of these methods, a long period of year is required for processing, a large-scale facility is required, and the cost is high.
[0007]
Recently developed methods of impregnating sugar alcohols such as lactitol and maltitol (for example, “Archaeology and Natural Science No. 28, 1993, p. 77-95.”, JP-A-8-57812, etc.) This is a preferable method because the treatment period of the water-immersed organic relic is shorter than that of the conventional method, and in fact, lactitol is used for the treatment of the water-immersed organic relic. However, there is no specific description about erythritol in the above publication. In addition, the method using lactitol that has been put to practical use because the treatment period is short requires the addition of a fine powder of lactitol monohydrate to promote crystallization after the impregnation treatment, and lactitol trihydrate. In order to prevent the formation of crystals, it is not a satisfactory method because of the disadvantage that it is necessary to dry at 50 ° C. for several days.
[0008]
The present invention aims to remedy the drawbacks of the prior art described above, and provides a method for preserving a water-immersed organic relic having the following advantages. 1) Since it has higher permeability than polyethylene glycol as well as lactitol, it has excellent crystallinity and does not have water of crystallization, the time and energy required for treatment can be reduced. 2) Since it is more non-hygroscopic than lactitol and is not decomposed by microorganisms, the water-immersed organic relics will not decay even in a hot and humid environment. 3) No distortion is observed in the water-immersed organic relic after treatment.
[0009]
[Means for Solving the Problems]
The present invention involves immersing a water-immersed organic relic in an erythritol aqueous solution, increasing the concentration by gradually raising the temperature of the aqueous solution, and then increasing the concentration, impregnating the water-immersed organic relic with the erythritol, This is a method for preserving a water-immersed organic relic comprising taking it out of an aqueous solution and drying it.
[0010]
In the present invention, an erythritol aqueous solution is prepared by dissolving erythritol in water. The aqueous erythritol solution is initially adjusted to a temperature of 20 to 60 ° C., preferably 40 to 60 ° C., and a concentration of 30 to 60%, preferably 40 to 60%, and the water-immersed organic relic is immersed. The temperature is gradually raised, and finally adjusted to 60 to 80 ° C., preferably 80 ° C., and the concentration is adjusted to 60 to 75%, preferably 75%. Whether the erythritol aqueous solution has impregnated the water-immersed organic relic is determined by the ups and downs of the water-immersed organic relic. When fully impregnated, the water-immersive organic relics sink.
[0011]
After completion of the impregnation, the surface of the water-immersed organic relic is washed with hot water at 30 to 60 ° C., and dried to a constant weight at room temperature to crystallize erythritol. Alternatively, after the impregnation is completed, the crystals are dried and crystallized at room temperature, washed with hot water at 30 to 60 ° C., dried again to a constant weight at room temperature, and erythritol is crystallized to immerse the organic residue. The saving process is completed.
[0012]
【Example】
EXAMPLES Hereinafter, although the Example and comparative example of this invention are shown and this invention is demonstrated further more concretely, this invention is not limited to these Examples. In addition, the water immersion organic relics used in the examples and comparative examples have a water content (weight of water absorbed ÷ dry weight × 100) of about 990%, almost the same size (diameter 5 cm, width) in all examples. 2.5 cm) was used.
[0013]
Example 1
(1) Into a 5 L stainless steel can with a lid, 3.2 kg of a 40% erythritol aqueous solution at 40 ° C. was placed, and a water immersion organic relic (left in FIG. 1) was immersed therein. The temperature was adjusted in a windy oven.
(2) When the water-immersed organic relics subsided, the lid of the stainless steel can was removed to evaporate the water, and the concentration of erythritol was gradually increased. As the concentration increased, the temperature was gradually increased, and finally the temperature was increased to 80 ° C. to increase the erythritol concentration to 75%.
(3) It took 14 days for the 75% erythritol aqueous solution to completely impregnate the water-immersed organic relic, and for the water-immersed organic remnant to sink. After completion of the impregnation treatment, the sugar solution on the surface was washed with hot water of 50 ° C. and allowed to crystallize by being allowed to stand at room temperature. It took 10 days to reach a constant weight.
(4) No distortion was observed in the water-immersed organic relics (left of FIG. 2) after the completion of all treatments (24 days).
[0014]
Example 2
(1) In the same manner as in Example 1, erythritol was impregnated in a water-immersed organic relic (right of FIG. 1).
(2) After completion of the impregnation treatment, crystallization was performed by drying at room temperature for 2 days. Crystals on the surface of the crystallized water-immersed organic relic were washed with hot water at 50 ° C. and dried at room temperature for 6 days until a constant weight was reached.
(3) No distortion was observed in the water-immersed organic relics (right of FIG. 2) after the entire treatment (22 days).
[0015]
The flowcharts of Example 1 and Example 2 are shown in Table 1.
[0016]
[Table 1]

[0017]
Example 3
(1) Into a 5 L stainless steel can with a lid, 3.2 kg of a 50% erythritol aqueous solution at 55 ° C. was placed, and the water-immersed organic relic was immersed therein. The temperature was adjusted in a windy oven.
(2) After one day, the 50% erythritol aqueous solution was sufficiently impregnated in the water-immersed organic relic, and the sample was sunk.
(3) The stainless steel can was removed to evaporate the water, and the concentration of erythritol was increased. The temperature was gradually increased as the concentration increased.
(4) It took 7 days to finally raise the temperature to 80 ° C. and raise the erythritol concentration to 75%.
(5) After completion of the impregnation treatment, washing, drying and crystallization were carried out in the same manner as in Example 1 or Example 2.
(6) Even when the initial concentration was increased and the increase in concentration was accelerated, as in Example 1 or Example 2, no distortion was observed in the water-immersed organic relics after the entire treatment (16 to 18 days).
[0018]
Comparative Example 1
(1) Into a 5 L stainless steel can with a lid, 3.2 kg of a 40% lactol aqueous solution at 40 ° C. was placed, and the water immersion organic relic was immersed therein. The temperature was adjusted in a windy oven.
(2) Whether or not lactitol has penetrated into the water-immersed organic relics is determined by the ups and downs of the water-immersed organic relics. When the water-immersed organic relics subsided, the lid of the stainless steel can was removed to evaporate the water, and the concentration of lactitol was gradually increased. As the concentration increased, the temperature gradually increased. When the water-immersed organic relics emerged, the lid was closed to stop the concentration increase. This operation was repeated, the temperature was raised to 80 ° C., and finally the lactitol concentration was raised to 85%.
(3) It took 29 days for the 85% lactitol aqueous solution to completely impregnate the water-immersed organic remains, and for the water-immersed organic remains to sink. After completion of the impregnation treatment, the sugar solution on the surface was washed with hot water at 50 ° C., dusted with lactitol monohydrate, dried at 50 ° C. for 2 days, and crystallized. Subsequently, the crystals on the surface of the water-immersed organic relics were washed with hot water at 50 ° C. and dried at 50 ° C. until a constant weight was reached for 2 days.
(4) No distortion was observed in the water-immersed organic relics after the entire treatment (33 days).
[0019]
Comparative Example 2
(1) In the same manner as in Comparative Example 1, lactitol was impregnated with water-immersed organic relics.
(2) After impregnation, the powder of lactitol monohydrate was dusted and dried at 50 ° C. for 2 days for crystallization. Subsequently, the crystals on the surface of the dried organic relics were washed with hot water at 50 ° C. and dried at 50 ° C. until a constant weight was reached for 2 days.
(3) No distortion was observed in the water-immersed organic relics after the entire treatment (33 days).
[0020]
The flowcharts of Comparative Example 1 and Comparative Example 2 are shown in Table 2.
[0021]
[Table 2]

[0022]
Table 3 shows the result of comparison between the lactitol method, which is the most excellent conventional method, and the present invention using erythritol.
[0023]
[Table 3]

[0024]
Compared with the lactitol method, which is currently the most excellent in terms of the short treatment period and strengthening of organic artifacts, the number of days required for the impregnation treatment was about one-half. The initial concentration and temperature of the erythritol aqueous solution were 50% and 55 ° C., respectively, and the impregnation treatment period could be shortened to about one-fourth that of the lactitol method by increasing the concentration. In the lactitol method, it is necessary to add crystal powder of lactitol monohydrate for crystallization, but it is not necessary in the present invention, and the operation is simpler than the lactitol method in consideration of low viscosity and ease of crystal peeling. Yes and excellent. The water-retaining organic relics are also sufficiently strengthened and the hygroscopicity is lower than lactitol.
[0025]
【The invention's effect】
Since the method for preserving a water-immersed organic relic according to the present invention has high erythritol permeability and excellent crystallinity, the time and energy required for the treatment can be greatly reduced. Furthermore, it has low hygroscopicity, and is excellent in non-rotatability, ant repellency, thermal stability and dimensional stability.
[Brief description of the drawings]
FIG. 1 Water-immersed organic artifacts before treatment (Left: Example 1, Right: Example 2)
[Fig. 2] Water-immersed organic remains after erythritol impregnation treatment (left: Example 1, right: Example 2)

Claims

Immerse the water-immersed organic relics in an aqueous erythritol solution, increase the concentration by gradually increasing the temperature of the aqueous solution, and then saturate the water-immersed organic relics. A method for preserving a water-immersed organic relic comprising drying.