填料とパルプの相互作用 ＩＩ 叩解の影響

Abstract

The influence of beating level of fibers on the structure and properties of paper was investigated. For this experiment, handsheets were prepared from either softwood kraft pulp or hardwood kraft pulp beaten to two level of freeness. The filler used was a precipitated calcium carbonate. The results may be summarized as follows:(1) The number of fibrous layers (Nf) at a given basis weight (excluding filler) increases with increasing filler content. The incremental increase in Nf is larger for sheets with a higher level of beating.(2) The geometrical parameters of filler aggregates differ depending on the fiber type, but are not affected by beating level of fibers. Both z-directional count and area fraction of filler aggregates for softwood sheets are lager than those for hardwood sheets.(3) The contributions due to fiber debonding (Sd) and the filler itself (Sr) to the total light scattering coefficient were calculated, assuming that these contributions were independent and additive. The calculation was bases on the light scattering coefficients of filled sheets and sheets with filler removed. It is apparent that the contribution due to fiber debonding is larger in highly beaten sheets, but that of the fiber itself does not change.The results obtained from both structural and optical property analysis show that the increase in optical efficiency of the filler with beating is due to the increased debonding of the fibers.