Aktuelle Messwerte 02.09.2010

pH-Wert: 8,53
alkalische Reserve: 1,8% CaCo3/kg
Verfestigung: 30%
Book deacidification

Since the beginning of the year 2010 we have been operating the BoCo1 in Brauweiler and using it are able to deacidify 140 Kg of books in a single work step.

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The book conservation process


  • Deacidification with decafluoropentane, magnesium oxide and magnesium carbonate (no alkoxide)
  • Activation of ingriedients with carbon dioxide

 

Book deacidification deep into the spine

A large number of books from the period after 1840 are also under threat from acidic decay. Book spines are particularly affected by the degradation process because of the high mechanical stress they are subject to. This is why Neschen AG began developing a new block deacidification technology a few years ago which transfers the successful process for single-sheet conservation to bound materials and thus makes deacidification deep into the spine possible.

New challenges for chemistry and technology

In comparison with single-sheet deacidification, machine conservation of bound materials poses new challenges for chemistry and technology, as the aqueous process is not appropriate for books. For this reason a non-aqueous process had to be developed that permits economical and environmentally-friendly processing which is not hazardous to health through which books can be deacidified as well as consolidated. In addition, a process had to be identified which permitted even distribution of the conservation solution throughout all the pages and deep into the spine.

GSK took up the research results of Neschen AG and developed and implemented a process for mechanical conservation of bound materials which is consistent with the latest technology in cooperation with the University of Applied Sciences and Arts, Hanover and development partners: the so-called "Book CP process”. The process is unique worldwide and has special characteristics which are unparalleled in the area of book conservation: It is the world’s first procedure that enables book conservation without alcohol or alkoxide additives. In addition to deacidification, simultaneous consolidation of most materials is possible. The conservation solution – whether with our without stabilisation – already has a strong cleaning effect in itself.

The book conservation process

In the book conservation process a three-phase suspension works on the material in a mixture especially modified for each item requiring treatment. Magnesium oxide neutralises the acids contained in the paper and ensures an alkaline reserve. The solution penetrates deep into the book pages by means of a carrier medium and additional gassing. The carrier medium has both a cleaning effect and expels water. Ethyl cellulose is used as a sizing agent and is optionally applied to consolidate the sheets. Once treatment is completed, the natural level of moisture must be reapplied to the bound archival materials during a reconditioning phase in order to initiate the actual chemical reaction which achieves deacidification. Measurements show that during this process book pages can be consolidated by up to 20 percent, with their pH value increasing to just over 9, leaving sufficient alkaline reserve in the book.

In the block deacidification unit in the GSK Archive Centre Brauweiler, up to 70 kg of bound material per working container can be simultaneously cleaned, deacidified and consolidated. Books are opened about ten degrees, placed in a cylindrical product carrier and fixated. The container is filled with the respective agent solution using an adjustable control system. To make sure the solution can work successfully on all individual book pages, CO2 is distributed evenly on the material via spray nozzles based on a predefined setting, thus guaranteeing continuous rinsing with the permanently reprocessed fluid. After the working process is completed, the solution is pumped out and returned to the closed-loop circulation system for reprocessing.

Workflow of book deacidification and cleaning

  • Determining treatment criteria
    A questionnaire is used to establish the criteria for treating the archival materials, and all steps that need to be carried out are determined in accordance with the customer’s wishes. Gentle treatment is guaranteed in all cases.
  • Sorting
    The bound materials are checked to determine if machine processing is possible. Books with leather binding, photographs or artwork prints are sorted. Badly damaged materials can be mechanically or manually deacidified in an aqueous single-sheet process.
  • Filling
    Books are opened about ten degrees, placed in a cylindrical product carrier and fixated.
  • Predrying
    Drying in a combined recirculated air/fresh air operation. After drying, the working container is subject to underpressure.
  • Drying
    After a drying phase exposed to hot air in an air-circulation dryer, the books are removed and stored in special rooms.
  • Reconditioning
    The deacidification process is completed during a reconditioning phase and the paper returns to its natural level of moisture.
  • Marking/packaging
    In a final step the bound materials are marked and packed.