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and enzyme will react in the pulp slurry dump chest with agitation for 2 until 3 hours. The reaction time is
controlled by adjustment of level in the dump chest.
1.4. Reining
Reining process is an important role to modiication the characteristics of iber. By reining
process the ibers become more lexible. It will give good effect to the paper properties such as stiffness,
opacity, tear strength or the paper smoothness. In this study, the pulp slurry is mixed with the vessel
enzyme before reined by using conical reiner. The reiner is operated in between 57 to 117 kilometer per
revolution for both stator and rotor plates with speed rotation rotor are 360 to 600 rpm. It will consume
the reining energy between 50 to 70 kWh per oven dry ton of pulp. The consistency of pulp slurry is 5
± 0.2 percent. And the pH of slurry is controlled in base condition 7 - 8 by adding Na2HCO3 prior to
the reiner.
1.5. Starch Addition
The paper contains starch derived speciically from cassava to help the mechanical bonding of enzyme
and reiner degraded vessels into the paper web by reinforcing the hydrogen bonds between the cellulose
ibers. The starch is added in the stock preparation stage in the range of 4 to 5 kilograms per ton of air dry paper
as well as added at the size press in the range of 25 to 35 kilograms per ton of air dry paper. The objective of
this study is inding the way for eliminating the vessel picking from the paper surface by some adjustment
such as; adjustment reining process, adjustment pH of pulp slurry or adding the enzyme.
2. Methodology
The method allows the UCWF paper to be produced such that the vessel cells present in the
tropical hardwood pulp are suficiently degraded by the action of the enzyme plus the mechanical action
of reining to allow the vessel cells to be mechanically incorporated into the paper web to a suficiently high
degree that they are not picked out of the inished paper during commercial printing. The method relates
to making UCWF grades of paper in the basis weight range of 40 to 200 gm
2
but speciically in the basis weight range of 50 to 120 gm
2
while the moisture content of the paper will be 5 ±2.5.
The paper has an oven dry cellulose iber content of 60 to 80. The cellulose iber content of the
paper is comprised of tropical hardwood pulp 60 to 100 and BSWKP bleached softwood kraft pulp
0 to 40. The tropical hardwood pulp is made up
of cellulose ibers derived from blends of Acacia Mangium and Acacia Crassicarpa in the range of
5050 to 1000 and 0100 respectively. The BSWKP is made up of cellulose ibers derived
from Radiata Pine, Douglas Fir, Sitka Spruce, Slash Pine, or any other coniferous wood species. The paper
contains from 10 to 30 by oven dry weight of either or both ground calcium carbonate and precipitated
calcium carbonate. The degree or amount of vessel pick out is measured using a laboratory printing device
called IGT test equipment. The IGT test equipment applies a ixed volume of standardized viscosity ink to
a press roll then applies the ink to the test paper with a standardized force. After the sample strip is printed the
quantity of vessel pick outs are counted and reported as vessel picks per area of printed paper. This IGT
printing method is used to determine the eficacy of the vessel treatment method.
3. Result and Discussion
Fig. 1 shows the effect of energy reining to the amount of vessel picking in the paper surface. When
the reining energy consumption is 40 sec kWht, the IGT test result found more that 12060cm2
of vessels. When the reining energy increased to 80 sec kWht, the numbers of vessels that are found
dramatically reduce to 20 60 cm
2
.
Figure 1: Reiner Energy Vessel Picking by IGT Test
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The main function of reiner is made the iber more swelling and ibrillation of ibers. The reining process
also cut the iber to the small size. From this process is expected that the vessel also cut to the smaller size
but it will cause negative effect to the next process of paper making. High number of iber cutting will create
high ines in the slurry that can effect to signiicant iber loss and strength reduction.
Adding vessel enzyme before reining process aims to make the vessel softer. During reining process,
the vessel will break to the small size or latten for accommodating better bonding in the paper surface.
4. Conclusion
