Weinheim, October 7, 2013. It’s the year 1764. Desbillions, the French Jesuit, flees to Mannheim from the dissolution of his order. With him in his luggage he has 6,000 books together with manuscripts in Latin and French. In the 25 years he spends in Mannheim before his death, he continues to expand his book collection. Today the 16,000 books are among the oldest works in the library at the University of Mannheim. Preserving this valuable treasure trove of books means restoring them professionally, for which the Freudenberg Group’s nonwovens are used. The Group also offers other innovative solutions for the manufacture of paper.
250 years later Susanne Kaerner is holding a book by Desbillions in her hands. She is a professional book binder and manages the workshop for the restoration of books in the library at the University of Mannheim. Around 60,000 volumes are to be found here, including Desbillions’ valuable collection. To ensure that the precious books are legible in the future, they have to be expertly restored. “Nonwovens are a valuable aid in the restoration of books,” explains Kaerner. “These valuable works can be preserved in this way for readers to enjoy for years to come.”
How does this work? The thin pulp which arises in the manufacture of paper, consists to a large extent of water. The rest are fibers. Paper can be cleaned with water. Kaerner therefore bathes a print from the 16th century in a large, shallow dish in three stages – each stage lasting 20 minutes.
The sheet of paper – now lighter, cleaner and firmer is placed on a paper drying rack, laid out with nonwovens. If a tear is to be repaired, it’s coated with paste and restored with Japanese tissue paper. The page is then covered in polyester and weighted to dry. The advantage – the pages no longer stick together as a result of the polyester fibers.
Kaerner expects high standards of the nonwovens: they must keep their shape with smooth surfaces and edges. And they should be temperature resistant, as it must be possible to iron a glued page dry. The fibers should remain smooth under stress, and there should be no fiber imprint visible on the restored paper.
„National and University libraries have asked about the nonwovens for the restoration of antique books. Nonwovens selected for this purpose are usually used for the protection of penetrating damp in electric cables,” explains Hans Henkes, Product Manager for industrial nonwovens at the Freudenberg Group. Freudenberg nonwovens are also used in the Austrian National Library and the Academy of Fine Arts, Vienna as well as in the Historic Archive of the City of Cologne and the Sprengel Museum in Hannover.
Contaminant gas filtration for paper production
The Freudenberg Group also supplies a filter technology especially suitable for use in paper production. Corrosive gases are released in the production of pulp for paper manufacture that can damage electronic components. Corrosive damage leads to unscheduled downtimes. “Gas phase filtration is an innovative process,” explains Thomas Schroth, Head of the Gas Phase Filtration market segment at Freudenberg Filtration Technologies.
The principal performers of this pioneering technology are tiny spheres of a few centimeters in diameter: pellets for gas phase filtration. There is huge potential in these unremarkable small pellets. Their application represents a significant development step forward in filter technology. How do they work? The pellets consist of aluminum oxide or active carbon, which are impregnated with various substances such as calcium permanganate, hydroxides or other active components, according to requirements. These active substances remove harmful gas molecules in combination with the open-pore structure of the pellets. During the gas phase filtration process they are transformed chemically into harmless salts. In addition to mechanical cleaning by an air filter, which catches and stores harmful particles from the air or liquids, the new pellets free the air of harmful gases through chemical conversion. The material is also new. Whereas synthetic nonwovens are increasingly used as a filter medium for particle filters, pellets are used in gas phase filtration.
Special lubricants for the paper industry
Improved technologies in the paper industry make it possible to raise production. At the same time, increased production is also linked to higher requirements of the components which should function maintenance free over the long-term without downtime. Special lubricants from the Freudenberg Business Group Klüber Lubrication adhere to surfaces very well even at high process temperatures in the processing machines, preventing residue from building on the paper during production.