• Title, Summary, Keyword: AKD

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Mechanism of AKD Sizing Development (AKD의 사이즈 효과 발현기구)

  • Jo, Byoung-Muk;Lee, Don-Sub
    • Journal of Forest and Environmental Science
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    • v.12 no.1
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    • pp.45-56
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    • 1996
  • Generally, it has been know that AKD develops sizing efficiency by forming the chemical bond with cellulose in neutral paper making. However, there have been many expriments in opposition to this theory. This study was carried out to find whether there is chemical bond between AKD and cellulose or not. Also, it was investigated that how much the reacted AKD forming chemical bond and the unreacted AKD contribute to sizing degree respectively if chemical bond presents, and what caused AKD sized paper to migrate under high temperature. Besides, this work experimented several factors having influences on AKD sizing in paper amking.

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Alkaline Sizing of Mechanical Pulp

  • Kim, Bong-Yong;Akira Isogai
    • Journal of Korea Technical Association of The Pulp and Paper Industry
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    • v.32 no.5
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    • pp.1-7
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    • 2000
  • Alkaline Sizing behavior and mechanism of handsheets, which were prepared from thermomechanical pulp (TMP) with alkylketene dimer (AKD), were studied in terms of the conditions of the handsheet-making. AKD content in the TMP handsheets was increased with increasing of AKD addition level and the addition of a polyamideamine-epichlorohydrin resin (PAE) clearly enhanced AKD retention as well as the resultant sizing performance of TMP handsheets. Although drying of the AKD sized TMP webs at $20^{\circ}C$ led to no or quite low sizing level, but TMP handsheets sized with AKD had higher sizing degrees with increasing of the temperature of heat treatment. Scanning electron microscopic observations of the AKD-sized TMP handsheets showed that AKD emulsion particles were present on pulp fiber surfaces independently without coagulation in the TMP handsheets dried at $20^{\circ}C$. Heat treatment of the AKD-sized handsheets resulted in disappearance of the AKD emulsion particles because of their melting and spreading. The addition of calcium carbonate filler to the TMP suspensions did not influence on AKD content in the TMP handsheets. Nevertheless, their sizing degrees clearly increased by the addition of $CaCO_3$filler. Probably, AKD molecules adsorbed on the $CaCO_3$filler particles contribute to the enhancement of sizing performance. Thus, AKD can give sizing features effectively to the TMP handsheets, when they are made under suitable conditions.

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Development and Application of Fast-cured AKD Emulsion (급속반응형 AKD Emulsion의 개발 및 적용)

  • Choi, Won-Hee;Shin, Jong-Ho;Park, Min-Tae
    • Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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    • pp.218-226
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    • 2002
  • 제지분야에서 중성 사이즈제로 광범위하게 사용되어지는 AKD emulsion의 사이징 효과의 발현속도가 낮은 단점을 보완하기 위하여, 기존 AKD emulsion에 추가 투입 사용함으로써 발현속도를 높여줄 수 있는 AKD 급속 반응형 정착제, 그리고 정착제를 사용하지 않는 초지 시스템에서도 급속 경화가 가능한 급속 반응형 AKD emulsion을 개발 하였다. AKD 급속 반응형 정착제의 투입량 및 종이 건조시간에 따른 사이징 효과를 상용화된 정착제와 비교하였으며 이 결과로부터 보다 빠른 사이징 효과발현을 확인하였다. 정착제를 사용하지 않는 시스템에서 급속반응형 AKD emulsion의 사이즈도 급속발현 효과를 확인하기 위하여 상용화된 emulsion과 사용량에 따른 사이징 효과와 건조시간에 따른 사이징효과를 비교함으로서 사이즈도의 급속 발현을 확인 할 수 있었다.

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A Study on Stability of AKD-Emulsion (AKD 에멀션의 안정성 평가)

  • Kwon, Won-Tae;Kim, Jeong-Hi;Shin, Jong-Ho;Park, Min-Tae
    • Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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    • pp.209-217
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    • 2002
  • Stability deterioration of AKD emulsion was studied with respect of the physical change of emulsion particles and the chemical change of AKD itself. Four kinds of commercial emulsions were kept at RT, 40, 50, and $60^{\circ}C$ water bath, respectively. Viscosity, particle size distribution, and solid contents of the emulsions were measured with storage time. At the same time, by performing NMR and IR spectroscopy analysis of the solvent-extracted AKD from the emulsions, the qualitative and quantitative information about the deformation of the AKD itself were obtained. AKD was gradually hydrolyzed to become dialkylketone and higher storage temperature accelerated destabilization of the AKD emulsions.

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A Quantitative Analysis Method for Studing AKD Hydrolysis (AKD 가수분해 연구를 위한 정량분석 방법)

  • 민춘기;신동소
    • Journal of Korea Technical Association of The Pulp and Paper Industry
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    • v.30 no.3
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    • pp.29-37
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    • 1998
  • In order to set up a proper AKD quantification method for studing AKD hydrolysis, a quantitative analysis method using Uv/vis spectroscopy was evaluated and compared to the conventional GC-MS analysis. Hydrolysis rates of AKD emulsions during storage at 4$0^{\circ}C$ were measured by the UV/vis analysis. Owing to its simplicity and capability of measuring the unreacted AKD significantly even in a small amount, UV/vis method proved to be more suitable for studing AKD hydrolysis than GC-MS analysis. AKD hydrolysis was affected by the types of emulsifiers. Polymer stabilized AKD emulsion hydrolyzed more rapidly than starch stabilized AKD.

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REACTION OF PAPER PULP AND ALKYL KETENE DIMER BY AGING TREATMENT DURING PAPERMAKIN PROCESS

  • Shin, Young-Doo;Seo, Won-Sung;Cho, Nam-Seok
    • Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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    • pp.83-83
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    • 2000
  • Alkylketene dimer was known as a cellulose reactive or alkaline size because it does not require to fix to the fiber as do the traditional rosin sizes. A proposed sizing mechanism of AKD was the formation of P -ketoester bond between AKD and cellulose which provides the permanent attachment and the orientation of the hydrophobic alkylchains outward. However, some questions about the reaction had arisen and thus, the sizing mechanism of AKD has been a subject of controversy for several decades. The major concern of the controversy is that AKD is really reactive with cellulose or not in the papermaking conditions. In this study, reaction between AKD and pulp fiber was investigated, in order to find out whether AKD forms P-ketoester with pulp fiber during aging under no catalyzed neutral condition with obvious spectroscopic evidence. In addition, effect of aging treatment on the sizing development was studied. It has been disclosed that, in absence of water, AKD reacted with cellulose to form P -ketoester linkage under no catalyzed neutral condition, while, in presence of water, most of AKD was hydrolyzed to a dialkyl ketone or P -ketoacid. In addition, during the aging treatment of AKD-sized paper, its typical IR spectra bands gradually were reduced, completely disappeared after 6hr aging, and formed new absorption bands at 1707cm-' and shoulder peak at 1700cm-' which refer to the typical dialkylketone absorption bands. Therefore, the formation of P -ketoester between AKD and pulp fiber is impossible in the practical papermaking process. It could be suggested that the sizing development of AKD-sized paper is obtained by next two mechanism: 1) formation of a thin-layer of AKD on the fiber surface through melting and spreading of AKD emulsion particles by heat and 2) the hydrolysis of AKD to dialkyl ketone which has higher melting point, during drying and storage of AKD sized papers.

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Behavior of AKD in AKD-sized Paper by Heating Treatment During Ageing (AKD 사이즈 처리한 종이의 저장중 가열처리에 의한 AKD의 거동)

  • Shin, Young-Doo;Seo, Won-Sung;Cho, Nam-Seok
    • Journal of Korea Technical Association of The Pulp and Paper Industry
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    • v.39 no.1
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    • pp.16-24
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    • 2007
  • This study was performed to investigate the reaction between alkylketene dimer(AKD) and cellulose molecules in AKD-sized paper sheet. AKD was added to highly beaten($80{\pm}3^{\circ}SR$) SwBKP(ca. 0.8% on pulp) in order to have much AKD retention in the paper sheet. This AKD-sized paper sheet was aged at different temperatures, $60^{\circ}C,\;80^{\circ}C,\;105^{\circ}C\;and\;125^{\circ}C$. Changes in FT-IR spectra of AKD in paper sheet during the ageing were measured. In addition, sizing degrees of the AKD-sized paper sheet pretreated for 30 sec. at $105^{\circ}C$ were measured by HST size tester during the storage at different temperature. IR spectra of AKD-sized paper sheet preheated at $105^{\circ}C$ for 30 sec. showed unchanged spectra two absorption bands at $1849cm^{-1}\;and\;1722cm^{-1}$ which refer to the typical AKD IR bands. However, these typical AKD bands were gradually reduced with increasing ageing, completely disappeared after 6 hrs. and formed new absorption band at $1706cm^{-1}$, which refers to carbonyl stretching vibration of dialkylktone. Eventually the AKD molecule was hydrolyzed to diakylketone without formation of ${\beta}$-ketoester with cellulose in paper sheet. After 6 days ageing, a little amount of ${\beta}$-ketoester bands was identified in 6 or 7 days ageing, because of the absence of water due to long-term heating. The same tendency was observed at different ageing conditions. At the practical papermaking process, AKD reacts prevailing with water, and mostly seems to be hydrolyzed to dialkylketene. Concerned to the sizing development, AKD-sized paper sheet was shown no sizing development at the initial stage of ageing at $60^{\circ}C$ after heating treatment at $105^{\circ}C$ for 30 sec., and gradually increased the sizing degree with increasing ageing, such as Hercules Sizing Tester (HST) 130 see for 12 hr, HST 300 sec. for 3 days and HST 400 sec. for 5 days. It was concluded that hydrolyzed AKD could contributed to the sizing development of the paper sheet.

Effect of Spreading of Neutral Sizing Agent, Alkylketene Dimer, on Sizing Development

  • Seo Won-Sung;Shin Jong-Ho;Cho Nam-Seok
    • Journal of Korea Technical Association of The Pulp and Paper Industry
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    • v.37 no.5
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    • pp.1-7
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    • 2005
  • The objective of this work was to investigate the effect of spreading behavior of the sizing agents (AKD or dialkyl ketone) on the sizing development of AKD-sized paper. There was a direct relationship between the spreading behavior of the sizing agents and their melting points. Both AKD and dialkyl ketone showed no substantial spreading until the temperature reaches to their melting points. Consequently, dialkyl ketone did not provide sizing development when the paper was heat-treated below $75^{\circ}C$, while AKD provided sizing effect even the paper heated at $50^{\circ}C$. The ketone, however, provided rather higher sizing effect than that of AKD, when the paper was heat-treated over $100^{\circ}C$. This result means that the ketone also gives sizing development to paper, moreover the ketone could give higher sizing effect to paper than AKD when it was melted and well spreaded on the fiber surface. While the ketone introduced to papers from hydrolyzed AKD emulsion could not contribute to sizing development.

Effect of White Water Quality on AKD Sizing of Linerboard (백수의 수질에 따른 라이너지의 AKD 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.2
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    • pp.9-15
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    • 2006
  • Neutral sizing is required for linerboard to solve the troubles in strength and process caused by recycled raw materials. AKD sizing efficiency can be influenced by process condition like white water quality, fines retention and so on. Therefore, this study was aimed to evaluate sizing performance of general and fast cure type AKDs using process water obtained from linerboard mill. To evaluate effect of process water quality on AKD sizing, white water was diluted with tap water at the different dilution ratios and UKP slurry was sized using the prepared water. Also, effects of inorganic and organic ion material on sizing were examined. When white water was used for stock forming, UKP sheet showed very low sizing degree. Sizing degree of sheet was increased with increase of dilution ratio because water quality was improved. Especially anionic organic material had a greater influence on AKD sizing than inorganic material. When white water quality was deteriorated, fast cure type AKD showed superior sizing performance to general type AKD.

지료조성에 따른 AKD사이징의 효과

  • 이현철;김봉용
    • Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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    • pp.90-90
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    • 2001
  • 1980년대 중반이후 국내에서는 기존의 로진-알람을 이용한 산성 초지 대신 중성 초지 로의 전환이 가속화 되어왔다. 현재 거의 모든 지종이 중성 초지 조건에서 생산되고 있으며 A ASA(alkenyl succinic anhydride)와 함께 대표적 중성 사이즈제로 널리 쓰이고 있는 A AKD(alkyl ketene climer)를 이용한 중성 사이징이 주류를 이루고 있다. 따라서 본 연구에 서는 국내에서 가장 많이 사용되고 있는 AKD를 이용한 중성 사이정의 효과를 파악하기 위 하여 지료 조성에 따른 AKD의 사이즈 발현 특성을 알아보고자 하였다. 공시펼프로는 미세분이 적은 미고해 NBKP와 신문고지를 실험실에서 탈묵한 DIP를 사 용하였으며, 정착제로는 PAM 및 분자량과 전하밀도가 서로 다른 3종의 Polyamine을 사용 하였다. 충전제로는 현장에서 사용되는 공업용 Clay, Talc와 탄산칼습을 사용하였다. 각기 다른 지료 조성에서 AKD 사이즈도의 발현과 효과를 조사한 결과 다음과 같은 결론을 얻었다. 일반적으로 미세분의 제거, 섬유손상의 억제, 적절한 정착제의 사용, 열처리 등의 조건 들이 갖추어 질 때 AKD의 사이정 효율을 보다 높일 수 있었다. 탄산칼습이나 Talc같은 낮 은 표면 에너지를 가지는 충전물들은 AKD 사이정에 긍정적인 효과를 나타내었다. 정착제 로서의 PAM의 첨가는 DIP에서 Polyamine보다 낮은 사이즈도를 보였으나 NBKP에서는 더 효과적이였다. Polyamine은 소량 투입만으로 일정수준의 사이즈도를 나타낼 수 있는 정착제 로 특히 DIP 사이정에 상당히 효과적이였으나 사용량과 충전물의 첨가에 매우 민감하게 반 응하였다.

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