Old mending in bound manuscripts and rare books can cause distortions on pages or new tears right beside the mends due to their stiffness and inflexibility. Additionally, they may also interfere with the readability of the pages as sometimes they cover text and illustrations. Detaching old mending papers glued with protein-based adhesives often requires a combination of moisture and heat. Nevertheless, not only has a uniform and accurate heat application always been difficult to achieve with the common heating tools, but the accessibility to the working area is also restricted when the mends are glued close to the spine fold of a bound volume.
This study aims to introduce a new heat transfer method to the removal of old mends glued with protein-based adhesives through an innovative heating device – the IMAT heater (Intelligent Mobile Accurate Thermo-Electrical Device). This device is a flexible and ultrathin heat transfer mat based on carbon nanotubes (CNTs), which was developed by the EUfunded IMAT Research Project. The IMAT heater features a rapid thermal response, a precisely controllable and stable heat regulation as well as a uniform heat distribution during a conservation treatment. Owing to its optional size, air permeability and transparency, different needs of specific applications can be met. Furthermore, due to the slight thickness and the flexibility of the mat, it is considered to be ideal when dealing with old mends glued close to the spine fold of manuscripts and rare books.
Experiments with applications and evaluation of coupling the IMAT heater with various hydrogels and Gore-Tex sandwiches are performed. After the investigation, a considerable temperature-related optimization on conservation treatment utilizing the IMAT heater is verified. An optimal working pattern of combining heat transfer with moisture introduction using the IMAT heater is suggested for the future conservation work. Besides, performance of each treatment variation correlated with different humidification sandwiches and treating temperatures is characterized. Finally, conservation treatments on three historical documents from the collections of the Bavarian State Library are successfully conducted: a medieval manuscript (BSB, Clm 18199), an incunable from the early years of printing (BSB, 2 Inc.ca 1726 a) and a printed book from the 18th century (BSB, Diss. 849 d, 16).