ブックタイトルConservation and Restoration of Western Paper

概要

Conservation and Restoration of Western Paper

5. Deacidification Treatment TechniquesDuring 1950s to 1960s, William J.Barrow defined that alkalization slowed thedeterioration rate of acidic paper materials.The necessity of deacidification treatmentto neutralize the acid in the paper for thelong term preservation is to be widelyrecognized. 11 Deacidification techniquesgradually developed through the 1970sand 1980s. In the 1990s to 2000s, activitiesbegan in comparing and evaluating thevarious commercialized deacidificationtreatments for their chemicals, methods andcost. 12-15 Below are principal deacidificationmethods divided into aqueous, gaseous, andnon-aqueous.Barrow already suggested aqueousdeacidification treatment in the 1960s whereneutralization is achieved by immersing theacidic paper in an alkaline solution. 11 Theaqueous treatment can achieve washing,neutralization and strengthening all in oneprocess and is beneficial for the treatmentof single sheet items. However aqueoustreatment is not suited for bound itemssuch as books which need dismantling andreassembling. Time and cost wise, aqueousdeacidification as a mass treatment requiredfurther study. Meanwhile, automation formass treatment of single sheet items wassuggested. The Buckeburg process developedin the 1980s, to fix, deacidify, and strengthensingle sheet items in one process. 16In order to preserve the massivecollection of acidic paper document, theLibrary of Congress experimented inthe 1970s with diethyl zinc, a gaseousmass deacidification treatment. Howeverthe treatment was discontinued afterdetection of odor in treated books,paper discoloration and deterioration ofadhesives. 17 Later in the 1980s, the BPA(Book Preservation Associates) methoddeveloped using ammonia and ethyleneoxide in a gas phase. Unfortunately thedeacidification results were not satisfyingand was discontinued in 1991. 18 In Japan,an improved BPA method called DAE(Dry ammonia ethylene oxide process) wascommercialized and been in operation since1999.19, 20Outside Japan, instead of gaseousdeacidification, non-aqueous deacidificationmethods developed. In non-aqueoustreatments, chemicals are used insteadof water, which makes bound volumespossible to deacidify. An alkaline substanceis added to the non-aqueous solvent intowhich the paper document is immersed,leaving an alkaline buffer within the fibres.From the 1970s to 1980s, non-aqueousdeacidification process developed such asWei T’oR, Sable, and FMC (Lithco process),but due to concerns over color change, odor,and environment, they were discontinued.Some of the technologies commercially inuse today are the BookkeeperR process byPreservation Technologies; PapersaveR fromCSC; and BooksaverR by Battele.15, 18LibertecR suggested a deacidificationprocess where a mixture of magnesium oxideand calcium carbonate is sprayed over anevenly opened book. This is considered a solidphase treatment but is often categorized as agaseous phase treatment. 1824