• 펄프종이기술
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• 제37권5호통권113호
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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.

• 펄프종이기술
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• 제34권1호
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• pp.1-6
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• 2002

Alkaline sizing characteristics of TMP (thermomechanical pulp) handsheets with AKD (alkylketene dimer) were studied under various conditions. The sizing degree of TMP handsheet was much lower than that of chemical pulp. Especially, the sized TMP handsheet dried at $20^{\circ}C$ showed no sizing features, but sizing degree of TMP handsheet was clearly Increased by heat treatment at $105^{\circ}C$. The sizing effect of TMP was also improved by addition of $CaCO_3$, but it was not affected by pH. Therefore, sizing effect of TMP with AKD can be improved to some extent by controlling stock condition and heat treatment of handsheet.

• 펄프종이기술
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• 제30권2호
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• pp.24-29
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• 1998

This study was carried out in order to elucidate the deterioration mechanism of paper according to various sizing chemicals. No additive paper and four kinds of papers containing rosin-alum, alum only, alkylketene dimer(AKD)-cation polymer and cation polymer only were treated by UV light to study changes of water-resistant, optical and mechanical properties from the view points of natural deterioration of paper. Since rosin chemicals have UV absorption at the relatively long wavelength region, rosins are degraded to form hydrophilic groups such as carboxylic acid from their double bonds by UV treatments. These phenomena caused the decreasing of sizing degree and wetting time in case of rosin-sized paper, while the UV treatments brought about the slight increase of wetting time in rosin-free papers such as no additive, alum and kymene only paper owing to the auto-sizing effect. Optical properties were primarily influenced by sizing chemicals. Rosin-sized paper showed lower brightness after UV and near UV treatment because of its UV instability.

• 한국가구학회지
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• 제19권3호
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• pp.172-179
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• 2008

The objective of this study was to investigate the influence of the water repellents' treatment on the water absorptivity and the dimensional stability of Korean red pine wood(Pinus densiflora). The alkylketene dimer(AKD), fluororesin emulsion(Wood-seal, WS), and paraffin wax emulsions(PW25, PW40, and PW1200) were used as water repellents. PW40 and WS were proved as excellent water repellents for pine wood, because the samples treated with these agents showed high contact angles and large reduction in water absorptivities. Also, the dimensional stability(antiswelling efficiency) of pine wood was considerably improved by water repellents treatments, such as PW40 and WS at the pressure of 2MPa. The water repellent treated woods with WS, PW40, and PW1200 at the pressure of 2MPa were relatively stable to the wet-dry cyclic leaching test.

• 펄프종이기술
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• 제39권1호
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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.

• 한국펄프종이공학회:학술대회논문집
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• 한국펄프종이공학회 2000년도 추계학술발표논문집
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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.

• Journal of the Korean Wood Science and Technology
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• 제27권1호
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• pp.79-87
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• 1999

포장재로 많이 사용되어왔던 발포 폴리스틸렌(EPS)이 환경공해의 원인이 되므로 이를 대체하기 위하여 농업부산물인 볏짚을 포장재의 원료로 이용하고자 볏짚펄프로 성형포장재를 제조하고, 첨가제인 전분, rosin size제, CMC, PEG, AKD, PAM을 첨가량별로 첨가하여 그 물성변화를 무첨가시와 비교하였다. 첨가제첨가시 포장재의 물성 및 경제적인 면에서 AKD 1%를 첨가하는 것이 가장 효과적인 것으로 판단되며, 흡수도는 모든 첨가제에서 첨가량이 증가함에 따라 무첨가시보다 감소되어 첨가제가 수분의 흡수를 억제하여 내수성이 증가하였다.

• 한국펄프종이공학회:학술대회논문집
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• 한국펄프종이공학회 1999년도 Proceedings of Pre-symposium of the 10th ISWPC
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• pp.50-55
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• 1999

Sizing development of AKD-sized paper by beta-ketoester formation has been debated until recent years because of absence of its obvious and direct spectroscopic evidence. In this study, reaction between AKD and cellulose was investigated to disclose the possibility of beta-ketoester formation between two components under no catalyzed neutral condition. In absence of water, AKD reacted with cellulose to form beta-ketoester linkage under no catalyzed neutral condition, while, in presence of water, most of AKD was hydrolyzed to a dialkyl ketone or beta-ketoacid. Therefore, the main mechanism of AKD sizing would not be the formation of beta-ketoester between AKD and cellulose in the papermaking process. It could be suggested that the sizing development of AKD-sized paper is obtained by next two mechanisms: 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 formation of ketone by the hydrolysis of AKD during drying and storage of AKD-sized papers.

• 펄프종이기술
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• 제32권5호
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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.

• 원예과학기술지
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• 제16권2호
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• pp.229-232
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• 1998

수입 육묘용 포트원지를 분석한 결과, 사용환경 특성상 일반종이보다 높은 습윤강도를 가지고 있었다. 습윤상태에서의 강도가 건조상태의 약 35% 이상의 인장강도와 약 60% 이상의 파열강도를 나타내었다. 육묘판의 강도를 유지하기 위해서 합성섬유를 약 30% 혼용하고 있었다. 또한 수분, 공기 등의 효율적 이동을 위하여 Gurley sec.로 측정한 투기도가 약 10초로 높은 수준이었다. 수입한 육묘용 포트원지와 유사하도록 실험실적으로 제조한 포트원지의 사이즈도는 AKD를 무게비로 건조 펄프의 0.5%를 첨가하여 충분히 얻을 수 있었다. 0.5% 이상 투입할 경우 사이즈 효과는 향상되나 강도 저하의 원인이 되었다. 강도적 측면에서는 Finex-B를 건조 펄프 무게에 대해 2%를 첨가하는 것이 가장 좋은 결과를 보였다. 실험실적으로 제조한 포트원지는 강도적 측면에서는 수입 포트원지보다 우수하나, 투기도가 다소 낮으므로 이를 개선하기 위한 노력이 필요하다.