• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
• /
• 1999.11b
• /
• pp.149-152
• /
• 1999

A new process for deinking of colored offset newsprint, i.e. enzyme treatment in cooperation with ultrasonic wave was developed in the present study. The physical characteristics such as fiber length, coarseness, crystallinity index of the deinked pulps were investigated and the sugar residues released from the treatment were analyzed. It was found that colored offset newsprint could be deinked effectively by cellulase treatment when ultrasonic wave was applied. The brightness increased by 5% ISO over that of control experiment and the pigment content was reduced markedly. Though the ultrasonic wave had little effect on the strength and crystallinity of the pulp, the treatment of enzyme combined with ultrasonic wave reduced the coarseness and fiber length to some extent. It was also found that ultrasonic wave could accelerate the hydrolysis of cellulose and hemicellulose during the cellulase treatment.

• Journal of Korea Technical Association of The Pulp and Paper Industry
• /
• v.29 no.1
• /
• pp.52-61
• /
• 1997

This study was aimed to decrease AOX(Adsorbed Organic Halide Compounds) by applying bleaching methods of A(HNO$_3$ ＋ NaNO$_2$) and $D^{(H/L)}$(dual pH chlorine dioxide bleaching) to conventional OCEDED bleaching stages. And so we investigate the effects of NSA treatment and the influence of production rate of ion species in chlorine dioxide and pulp mixtures according to various pH as well as dual pH on pulp bleaching. Finally the effects of AOC_DED^{(H/L)}ED^{(H/L)}$ bleaching stage were investigated by measuring AOX, brightness, kappa number and viscosity of pulps. A stage was treated by using 4% $HNO_3$ and 0.05~2.0% $NaNO_2$ on pulp and $D^{(H/L)}$ stage was like that pulp mixed with chlorine dioxide solution was adjusted at pH 7.0 and reacted in pulp cosistency 3%, S~20min, $70^{\circ}C$, and then successively for 160~175min at pH 4.0. It was found that suitable $NaNO_2$ addition rate was at 0.6% where the brigtness of pulp was most higher and pulp viscosity was not decreased much. Chlorate ($CIO_3$) was decreased according to pH increase but chlorite($CIO_2$) was highly decreased according to pH increase. And chloride was slightly increased with pH increase. The applying of A and D^{(H/L)}$ bleaching stages to some various multiple bleaching stages ($AOC_DED^{(H/L)}/EopD^{(H/L)} etc.$) had good results that brightness was increased more 2~3% ISO than conventional method(OCEDEopD), but viscosity was dropped by only 1~2cps.

• Journal of Korea Technical Association of The Pulp and Paper Industry
• /
• v.45 no.6
• /
• pp.24-29
• /
• 2013

In this study, we investigated the applicability of PCC(precipitated calcium carbonate) as a raw material for the manufacture of duplex-board. Papers were made with white-ledger stock collected from the actual duplex-board mill and PCC in a laboratory, and paper properties including bulk, ash content, tensile strength, burst strength, brightness and opacity were measured. The effect of PCC on the drying energy of duplex-board was also determined by measuring the moisture content of wet web and calculating drying energy reduction. PCC increased bulk and ISO brightness significantly, which means PCC can decrease the use of virgin pulp and recycled fibers. PCC decreased the moisture content of wet web, which means PCC can decrease drying energy consumption. However, paper strength decreased as addition levels of PCC addition increased. Therefore, the addition level of PCC must be determined considering the reduction of paper strengths.

• Journal of Korea Technical Association of The Pulp and Paper Industry
• /
• v.48 no.1
• /
• pp.100-110
• /
• 2016

Alkaline Peroxide Mechanical Pulping (APMP) of Pinus densiflora harvested from domestic mountains was explored. APMP contributes to various advantages including pulp quality, elimination of the need for a bleaching process, and energy savings. Sequential treatment of impregnation of bleaching chemicals and refining not only overcome the concern of alkaline darkening of wood chips during chemical impregnation, but it also brightens the chips to the desired brightness levels suitable for writing and printing papers. APMP pulping from Pinus densiflora was greatly influenced by the dosage levels of hydrogen peroxide and sodium hydroxide. Alkaline peroxide treatment was carried out by applying one of three levels of hydrogen peroxide (1.5, 3, and 4.5% based on the oven-dried weight of the wood chips) and one of three levels of sodium hydroxide (1.5, 3, and 4.5% based on the oven-dried weight of the wood chips). Other chemicals including a peroxide stabilizers and metal chelation were constantly added for all treatments. Chemical treatment with a liquor-to-wood ration of 9:1 was carried out in a laboratory digestor. Compared to BTMP, APMP pulping displayed outstanding characteristics including the less requirement of refining energy, the better improvement of tensile strength, the more reduction of shives, and the greater increase of pulp brightness. In particular, when 4.5% of hydrogen peroxide with impregnation during 90 minutes was used, the brightness of APMP reached 64.9% ISO. Even though bulk of APMP was decreased with the increase of sodium hydroxide, a better and improved balance could be achieved between optical and strength properties. The spent liquor obtained from the discharge of the impregnation process at the dosage level of 4.5% hydrogen peroxide exhibited an equal level of residual peroxide with BTMP. In conclusion, APMP pulping showed successful results with Pinus densiflora due to its better response to the development of optical and physical properties compared to TMP pulping.

• Journal of Korea Technical Association of The Pulp and Paper Industry
• /
• v.42 no.4
• /
• pp.78-83
• /
• 2010

In this study, the possibility of the use of a new raw material in paperboard industry was investigated. Fly ash is one of the residues generated in the combustion of coal and generally captured from the chimney of coal-fired power plant. This material is utilized in many industries including cement, soil stabilization, composite etc., but it is not used in paper industry. Three types of fly ashes were collected from Hadong, boryeong and Seocheon steam power plants and we investigated their properties by scanning electron micrographs and particle size distribution. Papers were manufactured with KOCC and fly ashes, and the physical properties such as bulk, tensile strength, internal bond strength and ISO brightness were measured to identify the effects of fly ash on the paper properties.

• Journal of Korea Technical Association of The Pulp and Paper Industry
• /
• v.46 no.4
• /
• pp.21-27
• /
• 2014

As a part of the study on manufacture of low density paper by organic bulky agent treatment, the effects of cationic fatty acid bulky agent on physical and optical properties of handsheets were elucidated. The research on change of physical and optical properties of paper samples according to bulky agent concentration, pulp type, and pulp combination were carried out. The results demonstrated that an increase of the concentration of cationic fatty acid bulky agent was proportional to an increase of the bulky properties of paper samples while tensile strength decreased. Also, the more the treated concentration of cationic fatty acid bulky agent increased, the more the ISO brightness of paper samples decreased while the opacity increased. The effectiveness of bulky agent with softwood bleached kraft pulp (SwBKP) was higher than that with hardwood bleached kraft pulp (HwBKP). In addition, the effectiveness with mixed pulps was higher than that with single pulp.

• Journal of Korea Technical Association of The Pulp and Paper Industry
• /
• v.42 no.1
• /
• pp.41-47
• /
• 2010

Increasing ash content of the paper is one of the most effective methods for saving raw materials and steam consumption and improving optical properties and better print quality. However, the increase of filler loading or filler content using a conventional wet end system is limited due to severe loss in strength properties, affecting runnability and product quality. This is because the filler has no ability to make bonding with cellulosic fibers. Therefore, if the technology to give filler the bonding ability is developed, the ash content of the paper can be increased more than ever. This study was carried out to modify PCC by coating its surface with starch contributing to better bonding with fibers. To prepare the modified PCC, cationic starch was selected as a polymer and then pretreatment was done by mixing PCC and cationic starch. Consequently, the pretreated PCC contributed to higher tensile strength, stiffness and opacity than the conventional filler, such as GCC and untreated PCC. However, CIE whiteness and ISO brightness decreased slightly compared to conventional fillers.

• Journal of Korea Technical Association of The Pulp and Paper Industry
• /
• v.38 no.3 s.116
• /
• pp.13-22
• /
• 2006

The analogs of cyclic hydroxamic acids containing N-OH group have been proposed to play effective laccase-mediators in kraft pulp bleaching with laccase/mediator system. The existing mediators (NHA, 1-HBT, VA), the best laccase-mediators reported so far, and selected several analogs of cyclic hydroxamic acids were evaluated as a laccase-mediator for kraft pulp bleaching. It was found that NHA was the most effective mediator for the Trychophyton sp. LKY-7 laccase (TrL) in kraft pulp bleaching with TrL/mediator system, increasing about 10% ISO of brightness and decreasing about 2.8 of kappa number after alkaline-peroxide bleaching. Of the cyclic hydroxamic acidstested, the NHP.1(N-hydroxypyridone analog) was shown to enable TrL to effectively degrade lignin in kraft pulp bleaching, demonstrating approximately similar effect with that of NHA. However, the effect of substituent patterns of cyclic hydroxamic acid analogs in kraft pulp bleaching was not observed. The inhibitions of NHA and NHP.1 on TrL were not exhibited in TrL/mediator system. As a new mediator for TrL, NHP.1 was considered to be able to use in kraft pulp bleaching with TrL/mediator system.

• Journal of Korea Technical Association of The Pulp and Paper Industry
• /
• v.44 no.1
• /
• pp.52-57
• /
• 2012

In this study, we investigated the possible use of a new inorganic material as alternative filler in the paper industry. The inorganic material is a mineral composed of calcium sulfate, that is generated when manufacturing phosphate fertilizer. The inorganic material was dehydrated by the thermal treatment to $200^{\circ}C$, $500^{\circ}C$, $700^{\circ}C$, and $900^{\circ}C$ to prepare white filler powders. Their basic properties, including color, particle shape, elements, and average particle size were identified. To determine the effect of new inorganic filler on paper's physical properties and strength, handsheets were prepared from HwBKP, SwBKP, and thermal treated inorganic fillers. Handsheets' ISO brightness, opacity, bulk, breaking length, and stiffness were measured. Results confirmed that thermal treated inorganic filler could be beneficial to the bulk and opacity of paper while maintaining higher level of breaking length and stiffness that is achieved using talc.

• Journal of Korea Technical Association of The Pulp and Paper Industry
• /
• v.47 no.6
• /
• pp.123-129
• /
• 2015

There are two kinds of cartons for beverage packaging, one is aseptic brick (AB) type and the other is gable top (GT). In this study, AB and GT were used as a raw material of recycled paper to investigate the recyclability at their varied blending ratios. Fiber consistency at pulping decreased as the blending ratio of AB increased. As a result, a lot of fines were generated from AB and flakes from GT increased because shear force in pulper decreased. Bulk of handsheets was more than $2.0cm^3/g$, and ISO brightness decreased as the blending ratio of AB increased. The best condition to recycle beverage cartons is to discriminate each cartons separately because of differences in the composition. However, there are problems such as the limit of the collection system and social costs. Therefore, it is assumed that the blending ratios of AB should be adjusted at less than 20% for effective recycling of beverage cartons.