Study of the effect of fiber components on the stability of book papers
Merle B. Shaw, Martin J. O'Leary · Journal of research of the National Bureau of Standards · 1936
Supplementing previously reported studies relating to the permanence of writing papers used for records, an investigation of the relation of papermaking materials and processes to the stability and other properties of book papers is in progress.This article reports the results of t est s of a number of pulps commonly used in fine printing papers as regards the stability of experimental unsized papers made from them.The effect of filling and sizing materials, respectively, will be reported in subsequent papers.The papermaking fibers used were representative commercial materials and consisted of four kinds of purified wood pulp, soda pulp and sulphite pulp (mixed in beater furnish), n ew rags (no. 1 white shirt cuttings), and old rags (no. 1 old whites and twos and blues, blended in the beater.)The pulps and half-stuffs ranged in quality from 78 to 93 percent of alpha-cellulose and from 3.8 to 0.4 in copper number.The composition of the beater furnishes was 85 percent of fiber and 115 percent of clay, which is a proportion commonly used for book papers.The experimental papers made from the rags had the characteristics of good book papers and showed no appreciable change in the accelerated aging (heat) test, which indicates a very high degree of permanence.One of the purified wood pulps produced a relatively stable sheet of satisfactory book-paper quality.The papers made from two of the wood pulps were somewhat less stable in the accelerated aging test, but that made from the remaining purified wood pulp was strong and relatively stable.The paper produced from the mixture of sulphite pulp and soda pulp was considerably less stable than the papers m ade from the purer fibers.A close relation was shown between the cellulosic purity of the fibers and the stability of the unsized papers made from them, but only a small amount of alum and no rosin size were used in the manufacturing process.The effect of these variables on the stability of the papers will be studied in the second part of the investigation.