Elucidation of manufacturing technology for paints using tung oil as a binder that are strong enough to engrave line pattern

2023 Fiscal Year Final Research Report

• Project/Area Number: 21K13143
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 03060:Cultural assets study-related
• Research Institution: Meiji University
• Principal Investigator: NAGAI YOSHITAKA 明治大学, 研究・知財戦略機構(生田), 研究推進員(客員研究員) (40880620)
• Project Period (FY): 2021-04-01 – 2024-03-31
• Keywords: 文化財科学 / 乾性油 / 桐油 / 豚血 / 塗料 / 伝世資料

Outline of Final Research Achievements

Model paints containing tung oil and pig’s blood, which are presumed to have been used for the historical material, were prepared. The model paints were measured for several physical　properties, and were analyzed by several methods. The addition of pig's blood to the model paints shortened drying time and increased hardness of the paint films. Some of the model paints had the same hardness as lacquer coating. Therefore, it was inferred that the model paints could be used for line engraving, a technique also found in lacquerware. It was possible to produce model paints with several physical properties equivalent to lacquer coating used. These results may help to clarify the manufacturing process of the paints that are assumed to have been used for the historical material.

Free Research Field

有機分析

Academic Significance and Societal Importance of the Research Achievements

これまでの研究では桐油と豚血を混ぜ合わせた材料は下地材として、琉球王国や中国、台湾において使われてきたとされている。本研究では類例の少ない桐油と豚血を含む塗料が使用されたと推測される伝世資料を対象としている。伝世資料の分析結果をもとにモデル試料を作製し、伝世資料とモデル試料の分析結果を比較した。一部の物性測定や分析において伝世資料とモデル試料の結果が類似しており、桐油と豚血を混合した材料が塗料として使用された可能性を示すことができた。また、現存する伝世資料の保存修復および復元の足掛かりになったといえる。