南方産広葉樹ならびに日本産広葉樹を対象に選び, 繊維の形態的特性と, 木材の容積重, パルプの保水性および紙葉の強度的特性との関係について検討を行なった。その結果繊維ディメンションの組み合せ比, 特にルーメン幅/繊維幅の比 (l/D) は, 木材の容積重, パルプの保水性, 紙の緊度, 剛度, 力比, 裂断長, 耐折度, 透気度などと相関関係が成立する。また繊維長/繊維幅の比 (L/D) は比引裂き度と相関関係が得られる。従ってこれらの繊維ディメンション比を指標にして, パルプ原木の品質の評価ならびに紙葉の品質を改善するための手掛りを得ることが可能となろう。

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The present article describes the method examined in laboratory scale in order to obtain a certain viewpoint on peracetic acid pulping. No experiment seems to have been published for peracid cookings.
A number of test cooking have been carried out on wood meals and shavings of pine and birch. One of these test runs uses the following cooking variables in order to maintain a high pulp yield and middle brightness : peracid concentration (10%), liquor ratio (20 : 1), cooking temperature (90°C) and digestion time (70-150 minutes) under ordinary pressure. Experiences in the use of the above cooking variables demonstrated very clearly that, from both industrial and research point of view, the usefullness of the peracid pulping should be emphasized. In this connection a few characteristics of peracid solution on storage conditions are involved.

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The brightness and the brightness reversion of high yield pulp are related to the color of lignin in pulp. Brown or dark brown color partially prevents lignin from utilizations. The exact nature of chromophoric systems in lignin, however, has not been known yet.
The purpose of this work was to discuss chromophoric groups and systems of softwood thiolignin responsible for their absorption spectra in visible region and reflectance spectra. From present knowledges of chemical structure of lignin the following chromophoric groups anal systems are predicted as to the color of lignin.
Chromophoric groups : alcoholic hydroxyl group, phenolic hydroxyl group, double bond, carbonyl group, carboxyl group etc.
Chromophoric systems : quinone, quinone methide, biphenyl etc.
The thiolignin used here was the commercial softwood thiolignin (free type) purified with dioxaneether. In order to distinguish the effect of chromophoric groups and systems the following samples were prepared from purified thiolignin (TL).
DA-1 and DA-3 : TL was methylated once with diazomethane and was methylated repeatedly three times, respectively.
DA+NaOH : DA-3 was treated with 1N sodium hydroxyde solution at 80°C in nitrogen gas for 1 hr.
DA+R-300 : DA-1 was reduced with sodium borohydride for 300 hr.
DS-1 and DS-3 : TL was methylated once with dimethyl sulfate and was methylated repeatedly three times, respectively.
DS+R-300 : DS-3 was reduced with sodium borohydride for 300 hr.
R-20 and R-500 : TL was reduced with sodium borohydride for 20 hr. and 500 hr., respectively.
The above thiolignins were purified with dioxane-ether to remove the effect of variation of apparent density. The reflectance spectra (Fig. 3) and the absorption spectra in ultraviolet and visible regions (Fig. 4) were observed by the same method adopted in the previous paper (Japan Tappi, 20, 369 (1966)). The visual efficiency, the dominent wave length and the percent saturation based on the XYZ system of C.I.E. were calculated from the reflectance spectra and the transmission spectra (Table 1).
Moreover, various thiolignins of apparent density were prepared to discuss the relationship between apparent density and color of thiolignin powder.
The results are as follows :
(1) The visual efficiency of thiolignin powder is increased linearly with decrement of apparent density (Fig. 1).
(2) The straight line relationships are observed between increase of methoxyl content and increase of the visual efficiency, and between increase of methoxyl content and decrease of the percent saturation (Fig. 5 and 6).
(3) Alcoholic hydroxyl group affects scarcely on the color of thiolignin. Phenolic hydroxyl group considerably affects on the color as much as carbonyl group (Fig. 7). Unit effect of carbonyl group, however, affects much more than that of phenolic hydroxyl group (Fig. 8).
(4) The methylated thiolignin reduced with sodium borohydride is still light-colored. Therefore, it can be predicted that stable free radical structure and carbonium ion structure in thiolignin may contribute markedly to the color of thiolignin. Moreover, molecular compound of electron donor-acceptor type is also expected to contribute to the color of lignin.

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The breaking strength of paper yarn can be calculated by Formula (64) of Report No. 30, Formula (75) of Report No. 31 and Formula (78) of Report No. 32. Therefore, the following methods can be adopted in the case of the chemical treatment.
1. The method to increase P₀ : (Breaking Strength of Raw Paper) by :
a. treating raw fibers b. treating raw papers c. treating tapes
2. The method to increace μ (Friction-Coefficient) by :
d. treating fibers e. treating tapes f. plastering fibers together g. plastering tapes together h. plastering yarns together all of which can be re-arranged as follows :
1) The method to treat raw fibers
2) The method to treat raw papers
3) The method to give the cut materical the treatment liquid instead of water, to twist and to heat the twisted yarn in order to attain the treatment effect
4) The method to give the cut material the treatment liquid, instead of water, to strengthen in the tape stage, and to give water and to twist
5) The method to treat yarns.
By the comparative study on the above 5 methods, 3) method was found to have the best treatment effect.

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