• Title, Summary, Keyword: neutral sizing system

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Compatibility of the Recycled Linerboard Made in Acid Sizing System under Neutral or Alkaline Papermaking Conditions (산성 사이징된 재활용 섬유와 중성 사이징의 상용성)

  • Seo, Man Seok;Lee, Kyong Ho;Lee, Hak Lae
    • Journal of Korea Technical Association of The Pulp and Paper Industry
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    • v.48 no.2
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    • pp.56-60
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    • 2016
  • Neutral or alkaline papermaking provides many advantages in paper strength and processing conditions. It also provides the opportunity of using calcium carbonate fillers in papermaking. These diverse advantages have made almost all paper machines of printing and writing papers run under neutral and alkaline conditions. On the other hand, linerboard machines, which use recycled papers as a raw material, are running under acid conditions using a rosin sizing system. Because the recycled raw materials used by the linerboard industry contain significant amounts of alkaline papers, the linerboard industry has an interest in the possibility of using the neutral or alkaline papermaking opportunity. In this study, the compatibility of the recycled linerboards under neutral or alkaline papermaking conditions was examined by recycling them under various pH conditions. The sizing degree of the papers recycled under neutral or alkaline was significantly lower than that of acid formed papers indicating that during the neutral or alkaline recycling process the rosin sized papers lost their sizing efficiency. Recycling of acid formed linerboards under neutral or alkaline conditions increased the amount of foam, and the foam contained substantial amount of solid materials derived from the acid sizing systems. Use of cationic polyelectrolytes including PEI and poly-DADMAC improved the sizing degree of the recycled papers under neutral and alkaline conditions. PEI decreased the foam generation as well while poly-DADMAC did not show any reducing effect of the foam. These results suggest that PEI forms coordinate bonds with rosin acid and precipitate them onto the surface of recycled fibers, while the reaction products between poly-DADMAC and rosin acid ions still remain water soluble under neutral or alkaline conditions.

Neutral Sizing of Linerboard Using Fast Cure Type AKD (급속경화형 AKD를 이용한 라이너지의 중성 사이징)

  • Lee Hak-Lae;Seo Man-Seok;Shin Jong-Ho;Youn Hye-Jung
    • Journal of Korea Technical Association of The Pulp and Paper Industry
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    • v.38 no.1
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    • pp.1-8
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    • 2006
  • To overcome troubles in strength and process of linerboard caused by raw materials, a neutral sizing which is usual in fine paper making can be considered. A new sizing agent is necessary to show good performance in a system with high conductivity and COD. In this study, fast cure type AKD was examined as a new sizing agent and compared with conventional AKD. The effects of fixing agent addition and drying condition were also investigated. Fast cure type AKD which has a higher cationicity showed better sizing degree than conventional AKD in spite of low addition level and no curing treatment. And when fixing agent of sufficient amount was added, sizing degree was improved for both AKDs. High cationicity is a crucial factor for neutral sizing of linerboard for obtaining fast and stable sizing degree. Drying with temperature over $100^{\circ}$ was desirable for developing sizing degree.

Development of Synthetic Sizing Agent Using Recycling Polyethylene Terephthalate and its Sizing Efficiency (Part 2) - Sizing efficiency of modified PET - (재활용 PET를 활용한 합성 사이즈제 개발 및 종이의 내수성 부여에 관한 연구 (제2보) - 개질 PET의 내수특성 평가 -)

  • Park, Jae-Seok;Kim, Hyoung-Jin
    • Journal of Korea Technical Association of The Pulp and Paper Industry
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    • v.42 no.2
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    • pp.95-101
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    • 2010
  • For the development of higher-sizing performance of paper, a sizing agent using recycled PET was synthesised. Polyester resin was extracted from wasted PET by subcritical hydrolysis and finally modified to synthetic sizing agent by mixing water-disperse PET with triphenyl phosphite(TPP). The modified PET was considered as an internal sizing agent in different wet-end papermaking conditions. The optimum condition in sizing efficiency was obtained in initial pH of 6.5 in case of rosin+alum system, and 7.5 in case of rosin+alum+PET system, respectively, and in addition amount of PET 3%. The sizing efficiency was also closely related according to the fiber properties of wet-end slurry, such as virgin fibres from UKP and recycled fibres from KOCC. The application of modified PET was good in strength improvement of paper, specially in tensile strength.