This review article introduces an outline of some new knowledge concerning filler loading in papermaking. The major subjects are : (1) mechanisum of filler retention, (2) methods for improvement of filler retention, (3) structure of filler loaded sheets, (4) optical property of filler loaded sheets, and (5) strength property of filler loaded sheets in relation to optical property.

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During recent years, surface strength of coated paper has been of much interest to the grafic arts industry.
Because of the increase in the printing speed, the printing defects caused by picking have become a major problem in the off-set printing. Picking problem can be quite complicated and still more on solving it in relation to other printabilities. Pick resistance is always essential and important on discussing the print quality of paper.
In this article, several factors which can influence this pick resistance are discussed.

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This paper describes current topics in pulp and paper making process instrumentation technology, especially this month in abstract aspects.

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昭和63年12月紙パルプ技術協会のメンバー会社と一部の製紙会社にお願いして, COD自動計測器の実態調査を行い, 23社50工場73台の回答が得られたのでその集計結果を報告する。

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In “Solvolysis” pulping, chips were cooked in the aqueous solution of phenols available from lignin degradation products. Unbleached pulps were easily defiberized even at kappa number as high as 30 to 60 and the yield ranged between 50 and 60% for hardwood and softwood. The pulps could be sufficiently washed by the internal solvent extraction and the following internal and external hot water washing. Oxygen delignification and the conventional three stage bleaching gave bleached Solvolysis pulps with enough brightness and strength property for making printing paper.

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In the previous paper (part 1) of this series, we reported that resin speck formation was primarily influenced by “the appearance frequency of resin” in canals, and secondly by the charactericstics of resin. In the part 2 report, the quantitative basis for resin deposition was given in terms of “the average deposition index of resin specks” to the qualitative concept “the appearance frequency of resin”. In this paper, both resin speck formation in Shorea kunstleri pulps and deposited resin as the screen rejects are discussed from the view point of chemical constituents.
The extractives from the wood of S. kunstleri are mainly composed of bergenin, as shown in Fig. 1, 2, and 10., which is dissolved out during alkaline sulfate pulping. Therefore, factors responsible for resin deposition in the pulping of S. kunstleri are the neutral resins consisted of sesquiterpenoid polymers, triterpenoids, and steroids in vertical resin canals as shown in Fig. 3, 5, and 10. Relationships among the amounts of extractives, deposited resin, and speck area obtained from the respective division (A-E) are shown in Fig. 1. Distribution of the total extractives in the wood discs increases from the central heart wood (A) to the outer heart wood (D). Corresponding increases in both resin speck area and deposited resin are found in the bleached pulps prepared from the wood discs (A-D) as is also shown in Fig. 1.
Though the disc D contains the same series of resin canals in number as those in C, the former gives more speck area and more deposited resin than the latter. One of the important reasons may be ascribed to the presence of canals with larger diameter in the former. Furthermore, besides the resin in vertical resin canals, presence of the additional amounts of resin probably exuded from the paratracheal parenchyma cells can be observed in number of vessels of the disc D under a stereoscope microscope as shown in Fig. 5b of the part 2 report. The latter resin (PR) contains the larger amounts of triterpenoid and steroid than those in canal resin (CR) as shown in Fig. 10.
Compared to those from the disc D, however, a larger amount of extractives content from the disc E involving sapwood as a part affords less resin speck area and less deposited resin. This is primarily due to the shortage of series of resin canals in number but abundance of phenolic constituents, e.g. bergenin in the disc E.
Moreover, as shown in scheme 1, 2, and Fig. 4, 6, 7, separation and identification of the resin components were made, and they confirmed the presence of β-amyrin and lupeol of triterpenoid, stigmasterol, campesterol and β-sitosterol of sitosteroid, and finally β-, and γ-resene of sesquiterpenoid polymer. γ-Resene is a new polymer tentatively named, and is easily soluble in MeOH but not in CHCl₃. The molecular weight distributes between 8, 000 and 800. This contains a larger ratio of oxygen in the molecule than those in β-resene, but gives very similar degradation products by pyrolysis GCMS to those from β-resene.
On the other hand, the results in the re-addition test are shown in Fig. 8 and 9. Total areas of resin speck in paper sheets are found in descending order of β-, γ-resene, and a complex mixture of triterpenoid and steroid. In addition, significant effect of hydrophobic polymers on expansion of resin speck area is shown in descending order of β-, γ-resene, and pitch polymer from the bleachery of E stage of japanese kraft pulp mill.
Based on the mentioned above, not only triterpenoid and steroid in the vertical resin canals but also those exuded from the paratracheal parenchyma indicate a function as agglomerated con-stiutuents, whereas polymers of β-, and γ-resene from the vertical resin canals function as core substances in the agglomeration of resin.

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