JAPAN TAPPI JOURNAL

Show abstractHide abstract

Japanese red pine wood was made into thermomechanical fiber (TF), and then TF was cooked three-times with oxygen and alkali to obtain pulp for paper making, namely TF-OAP (cf. Fig. 1). On the other hand, two kinds of pulp, namely, TF-D-OAP and TF-P-O-AP were prepared by the single-stage oxygen-alkali cooking, respectively, of the chlorinedioxide-pretreated TF and the peracetic acid-pretreated TF (cf. Table 1, Fig. 2, 3). The chemical and physical properties of these pulps were examined, and were compared with those of kraf t pulp (KP) and holocellulose pulp (HP) from wood chip and those of kraf t pulp (TF-KP) from TF (cf. Table 2, Fig. 4-7, Photo. 1, 2).
TF-OAP having brightness of 40 and kappa number of 41 was obtained in yield of 50.3% based on wood. Polymerization-degree of the pulp was approximately half of that of TF-KP. TF-OAP showed the lateral order distribution curve having only one peak in a region of considerably low order. TF-OAP reqired much less refining energy with PFI mill to reach a given freeness than did the other pulps. Water retention value of the beaten TF-OAP was higher than that of the beaten TF-KP, and much lower than that of the beaten HP. Pertial mechanical-damage of fiber of the beaten TF-OAP was observed by the S. E. microphotographs of the hand sheet surface. All of the strengths, especially tear and zero-span breaking, of TF-OAP were lower than those of TF-KP.
TF-D-OAP and TF-P-OAP contained less residual lignin, and the yield, brightness, polymerization-degree, and strengths of them were much higher than those of TF-OAP. These pulps were higher for breaking, burst, and folding strengths and lower for tear and zero-span breaking strengths. These results might be attributed to the selective and uniform delignification of the pretreated TF, as compared with the delignification of TF in the oxygen-alkali cooking stage.
Strength properties of TF-KP were inferior to those of KP, suggesting the thermomechanical treatment in this experiment inflicted considerable physical and chemical damages to the fiber. On the production of TF-OAP, accordingly, it is important to prepare TF of better properties.
HP had superior breaking and burst strengths, although had poorer folding and tear strengths, in comparison with the strength of KP.

View full abstract

Download PDF (2295K)

Kraft paper is used for insulation in oil immersed equipments such as condenser, transformer. The reason is that Kraft paper has given satisfactory performance on electrical and mechanical properties.
As for life, however, thermal degradation occurs due to temperature rise in operation. Example of these kinds of the Kraft paper are cyanoethylated Kraft paper and dicyandiamide modofied paper. Moreover Kraft paper containing morpholine, oxyalkylamine, aromatic-polyamine, para-toluene-sulfoneamide, etc are well known.
This paper describes a thermal aging characteristics of new n-butyl carbamate modified Kraft paper, compatibility between n-butyl carbamate and polyvinylformal wire, thermal dissociation products of n-butyl carbamate and thermal aging characteristics of insulating oil.

View full abstract

Register with J-STAGE for free!