PENGARUH PENCAMPURAN BEBERAPA JENIS KAYU DAN PERUBAHAN SULFIDITAS PROSES SULFAT TERHADAP SIFAT PENGOLAHAN DAN KUALITAS PULP KAYU KARET

Abstract

One of the plant species which can be cultivated  and enables the industrial plantation forest to be established  for its  timber/wood  utilization  is rubber  trees. In dealing with  rubber  wood for pulp/paper processing, the residual latexes, despite in small amount, can bring about some nuisances, i.e. the troubles during the cooking, washing, and bleaching, and the appearance of dark pitch­spots on the surface of the resulting  pulp/paper sheet.

Inherent wich  such, the main aim of this research was to remove or reduce to  some effective degrees  the  residual  latexes from  rubber  wood pulp  cooked  using   kraft  (sulphate) process  by regulating the sulfidity of the cooking liquor (20,25,30%), and by mixing rubber wood with four other wood species, i.e. sengon (Paraserianthes falcataria), jabon  (Anthocephalus cadamba), tusam (Pinus merkusii Jungh et de Vries), and ekaliptus (Eucalyptus   sp.)  each with their specific gravity of 0.63, 0.30, 0.52, and 0. 78, respectively.

Changes in suljidity from 20 to 30 percent brought about significant decrease in the number of pitch­spots, caused by  the  residual  latexes, on  the  surface of  the  resulting  kraft pulp  sheet. Meanwhile,  changes  in mixture between rubber wood and four  other wood species  with relative proportion  (oven­dry weight)  from  100:0 to  50:50,  and finally  to 25:75 brought about also the decrease in the number of pitch­spots.

In  the same  occasion, changing the  suljidity from 20  to 25 percent  caused  the increase  in breaking­length from 3170 m to 3615  m (increasing by 14.04  percent); tear factor from 97. 776 to 111.100 (increasing by 13.63 percent); and burst factor from 42.913 to 53.623  (increasing by 24.96 percent).  However,  further  changes in sulfidity from 25 percent  to 30 percent brought  about the decrease in breaking length  and burst factor to  3232 m (decreasing  by 10.59  percent) and 48.631 (decreasing by 9.31 percent), respectively. In another case,  changes in relative  proportion  of mixture between  rubber wood  and four  other  wood  species from  100:0 to 25:75  induced the significant increase in burst factor and folding endurance from 44.163 to 54.357 (increasing by 23.08  percent) and from 39.47  to 83.93  (increasing  by

112.64  percent).