NEW PULPING METHOD FOR LINERBOARD

Traditionallykraftwasusedaslinerforlinerboard.Thekrafpulpingyieldwaslow,andairpollutionhigh.SomeresearcheshaveshownthattheyieldofAS-AQpulpwasmuchhigherthanthatofkraft,andthestrengthwasequaltothatofkraft,exceptforasome-whatlowertearstrength.Thewashingprofi-clencyofAS-AQpulpwashigherandairpol-lutionwasmuchlowerthanthoseofkraft.SoAS-AQpulpwasthoughtasapromisingre-placementofkraftforlinerboard.lntheresearchPinuskoraiensiSandLarljgmehniwereusedasrawmaterials,withtheL,(3')experimentaldesignan…     

A new modified pulping process alternative to sulphate method “Alkali-Sulfite-Antraquinone-Ethanol (ASAE)”

Summary In this study, ASAM method was modified by the use of ethanol instead of methanol. This new organosolv pulping method is referred to as ASAE. Brutia pine (Pinus brutia Ten.) was chosen as raw material in cooking because of its wide-spread usage in Turkish sulphate mills. 28 cooks were made by changing the cooking conditions systematically to achieve the most effective cooking parameters for yield and physical properties of ASAE pulps. Also, a control sulphate cook was made. After statistical evaluations of the data optimum pulping conditions were determined to be 20% Na₂SO₃ with 50% ethanol ratios and 150 min cooking time at maximal temperature. It was found that ASAE pulps had higher yield, viscosity, brigthness and strength properties than sulphate control pulps with the exception of breaking length. Furthermore bad-odour problems were absent during the blowing and washing process in the laboratory trials.     

Influence of process variables on the properties of pulp and paper sheets obtained by sulphite pulping of olive tree wood

Summary A central composition design was developed to study the influence of process variables (temperature, pulping time, sulphite concentration, anthraquinone concentration and liquid/solid relation) on the properties of pulps (yield, holocellulose, α-cellulose and lignin contents, and brightness) and the paper sheets (stretch, burst index and tear index) obtained from them, in the sulphite pulping of olive tree wood. Equations that reproduce the properties of pulps prepared by sulphite pulping and of paper sheets obtained from it are reported. The proposed equations fit the experimental yield and the holocellulose and α-cellulose contents of the pulps with errors less than 5%, as well as brightness with errors less than 10%. Also, they reproduce the lignin content of the pulps, and the stretch, burst index and tear index of the paper sheets with errors less than 15%. Obtaining pulps with acceptably high yield, holocellulose and α-cellulose contents, and also a high brightness, in addition to low lignin contents, entails operating at a temperature of 193 °C for 143 min, using a sulphite concentration of 19.85%, an anthraquinone concentration of 0.1% and a liquid/solid relation of 6.24. These are also the most suitable conditions for obtaining paper sheets with a high stretch, burst index and tear index. Received 23 April 1998     

竹子深度脱木质素蒸煮与常规硫酸盐法蒸煮的比较

为了提高竹浆性能和减少环境污染,对福建丛生小径竹进行了实验室模拟延伸改良连续蒸煮(EMCC)和常规硫酸盐法蒸煮(CKC)的研究。结果表明,EMCC蒸煮通过分段加入蒸煮药液和在逆流段进行药液置换,比CKC具有更高的脱木质素选择性。在蒸煮相同卡伯值的竹浆时,EMCC浆比常规硫酸盐浆(CK浆)具有更高细浆得率、较低粗渣率、更高粘度和更好强度性能。在相同的打浆度下,EMCC浆抗张指数、耐破指数和撕裂指数都比常规硫酸盐浆高。     

Evaluation of paper permanence

Summary The thermal stability of papermaking pulps under conditions of accelerated aging and at pyrolytic temperatures was examined. Degradation was found to be extremely complex and influenced by both the technical processes of papermaking and by the experimental methods used. At moderate temperatures, as used for accelerated aging, the folding endurance test was found to be a sensitive measure of degradation. Methods of reducing the variability of the test were considered, and a new technique capable of handling widely different results was developed and evaluated.Several papermaking pulps were artificially aged and the resultant loss of strength attributed to the interaction between a gradual fiber strength reduction and a rapid increase in interfiber bonding. Excessive initial inter-fiber bonding decreased handsheet stability. Softwood sulfite and kraft pulps were more stable than a birch kraft pulp, but the behavior of sulfite pulps varied greatly. The presence of lignin or a high hemicellulose content was not of itself sufficient to cause rapid aging.The pyrolytic behavior of pulps was investigated using thermogravimetric analysis. Papermaking pulps had mean pyrolytic activation energies between 30–45 kcal/mole. The activation energy decreased as the reaction proceeded. Correlation of these activation energies with the rate of loss of physical properties during accelerated aging was not good. The results indicated that the rate determining reactions for pyrolysis and for low temperature degradation are different but that the pyrolytic behavior is partially determined by the supramolecular structure. Empirical stability indices, based on both the integral and differential thermograms, were calculated, and these correlated well with the relative rates of loss of physical properties.A large part of this paper is based on the thesis of R. D. Carwell. Contributions were also made by L. Lyon and M. C. Varshney. This work was partially funded by the National Bureau of Standards     

Characterization of lignin-carbohydrate linkages in the residual lignins isolated from chemical pulps of spruce (<Emphasis Type="Italic">Picea abies</Emphasis>) and beech wood (<Emphasis Type="Italic">Fagus sylvatica</Emphasis>)

To investigate the linkage types between carbohydrates and lignin, residual lignins were isolated from three different unbleached pulps [kraft, alkaline sulfite anthraquinone methanol (ASAM), and soda with anthraquinone (AQ) and methanol] of spruce and beech wood and then characterized by oxidation with 2,3-Dichloro-5,6-dicyanobenzoquinone and followed by Prehm’s methylation. In residual lignins, sugar moieties were bound to lignins via benzyl ether bonds. In particular, galactose and mannose are predominantly linked to lignin fragments in residual lignins of spruce wood, while xylose and galactose are favored in the formation of LC bonds in the residual lignins of beech wood. In the case of hexoses, primary hydroxyl groups (C6 position) preferentially take part in benzyl ether linkages. Hydroxyl groups in the C2 and C3 positions of xylose participate in LC bonds and a small portion of arabinose was notably connected to lignin via the C5 position. Approximately seven or eight sugars were connected in soda/AQ/methanol residual lignin per 100 C9 lignin units, while the frequencies of LC bonds in kraft and ASAM residual lignins were distinctively less at one to three sugars per 100 C9 lignin units. The publication of this article was made possible by an Emachu Research Fund. The authors are grateful for the fund.     

Thioacidolytic analysis of residual lignins isolated from the chemical pulps of spruce (Picea abies) and beech (Fagus sylvatica) wood

Eight different residual lignins isolated from unbleached chemical pulps [sulfite, kraft, alkaline sulfite-anthraquinone-methanol (ASAM), soda/AQ/MeOH] of spruce and beech were characterized using gel permeation chromatography (GPC), thioacidolysis, and desulfurization to determine average molecular weight, amounts of uncondensed β-O-4 linkages, and dimeric linkage patterns, respectively. The total amounts of G-CHSEt-CHSEt-CH₂SEt and S-CHSEt-CHSEt-CH₂SEt were markedly reduced in residual lignins to 40% to 80% of the values for the corresponding milled wood lignins (MWLs). The number of dimeric units determined by thioacidolysis and desulfurization of the residual lignins was decreased by onehalf to one-fifth compared to the MWLs. Among the diverse types of dimeric units, reduction of β-1 and β-5 units was significant in most of the residual lignins, with the exception of beech ASAM residual lignin. Compared to beech MWL, 40% more C6–C3 main monomers were detected, whereas the relative composition of the dimeric units in the beech residual lignin was very similar to that in the beech MWL. The average molecular weights of residual lignins were less than those of the MWLs. However, the average molecular weights of the spruce kraft and soda residual lignins were determined to be higher than those of the corresponding MWLs.     

A mathematical model for neutral sulfite pulping of various broadleaved wood species

Summary A mathematical model for neutral sulfite pulping process was derived. This model represented by a linear logarithmic relationship of the main pulping characteristics (yield and lignin content) to time and temperature parameters, both determined by the H-factor, is expressed by a logarithmic straight line equation. The relationship of yield to lignin content in the high yield pulps after neutral sulfite pulping is also expressed by a logarithmic straight line equation. A suitable way to calculate the main characteristics of neutral sulfite pulping is the power form of the logarithmic straight line equation for the dependence of the ratio yield/lignin vs. lignin content, yield/H-factor vs. H-factor, lignin/H-factor vs. H-factor and their mathematical equivalents (i.e. reciprocal ratio and/or product). A set of power equations characterizing the relationships yield vs. lignin content as well as yield and lignin content vs. H-factor for woodpulps prepared by neutral sulfite pulping of various broadleaved wood species are given.     

世界木材制浆技术新进展

文章论述了木材制浆技术的新进展，在硫酸盐法制浆技术的革新方面，推荐了间歇蒸煮的快速置换加热（ＲＤＨ）技术与连续蒸煮的改良连续蒸煮（ＭＣＣ）和深度脱木素改良连续蒸煮（ＥＭＣＣ）技术。还介绍了超高得率制浆方法，特别是碱性过氧化氢机械制浆（ＡＰＭＰ）法和爆破制浆（ＥＰ）法，用这两种方法生产的纸浆得率高、白度高、强度高、能耗较低。     

Distribution of methyl-esterified galacturonan in chemical and mechanical pulp fibers

The effects of chemithermomechanical pulping (CTMP), high-temperature (HT)-CTMP pulping, and kraft pulping on the distribution of the pectin polymer, methyl-esterified polygalacturonan have been qualitatively evaluated using immunocytochemistry. Pectin was immunolocalized using an antibody (JIM7) specific for partly methyl-esterified polygalacturonan. A fluorescent antibody was linked to JIM7 and analyzed by epifluorescence microscopy. Pectin was found in both chemithermomechanical pulps in similar uneven patterns: Some fibers showed no labeling, whereas others showed extensive labeling in patches restricted to the fiber surfaces. Pectin labeling of bleached and unbleached kraft pulps did not show any presence of pectin. Labeling was correlated to the presence of compound middle lamella tissue left on the CTMP-treated surfaces. Pectin on pulp-fiber surfaces may affect the interfiber bonds and thereby the pulp properties.     

中国引种澳大利亚相思树种制硫酸盐浆适应性研究

无论是从林业角度还是在制浆性能方面，不同种源间存在明显差异。本文研究了我国亚热带工区引种澳大利亚相思树的基本密度纸浆产率、制硫酸盐浆和漂白性能，比较了不同种源间的差异。研究结果表明，在有效碱用量为１２．５％－１５．５％时纸浆得率达５１．２％－５３．６％，经ＣＥＨＤ四段漂白后，所得纸浆性能可以满足配抄印刷和包装类用纸要求。     

Investigation on physical and mechanical properties of pulp–plastic composites from bagasse

High-density polyethylene (HDPE), bagasse fibers treated by four pulping processes (AS-AQ (alkaline sulfite anthraquinone), SODA-AQ (soda anthraquinone), MEA (monoethanolamine) and chemical–mechanical pulping (CMP)), three levels of nano-SiO₂ (0, 2, and 5?wt%), and maleic anhydride polyethylene as coupling agent were used to produce pulp–plastic composites (PPCs) by injection molding. The physical and mechanical properties of corresponding composites were evaluated according to ASTM standards. The results showed that compared to untreated bagasse/HDPE composite, the addition of bagasse pulp fibers increased significantly the mechanical properties such as tensile strength and modulus, flexural strength and modulus, and hardness. The chemical pulps-reinforced composites showed better mechanical strengths than that of CMP-reinforced composites, but in some properties, CMP pulp composites have comparable results to the chemical pulp-reinforced composites. Natural fibers (untreated and treated) increased water absorption and thickness swelling of composites compared to pure HDPE. The addition of nano-SiO₂ particles showed both increasing and decreasing trends on physical and mechanical properties ofPPCs.     

Fiber- and fine fractions-derived effects on pulp quality as a result of mechanical pulp refining consistency

High-yield pulping of wood chips using low-consistency (LC) refining in combination with primary-stage high-consistency (HC) refining has previously been shown to produce paper with quality parameters (tensile strength and light-scattering coefficient) commonly targeted for newsprint with significantly less refining energy input than using only HC refining. However, questions remain on the differences in the refining action between the two refiner types and for high-yield pulping, the refiner energy demand is a crucial process parameter. Therefore, fines- and fiber-fraction development in HC and LC refining has been studied in detail using Bauer-McNett fractionation, and the respective tensile strengths of the different fractions have been compared. Quantitative and qualitative (morphological) characteristics of the isolated fine fractions have also been analyzed in detail using a newly developed automated fluorescence microscopy method and scanning electron microscopy. The results suggest the difference in LC/HC pulp properties (strength and optical) is partly derived from deviating fiber and fines morphologies and mass balances. The quality of the fines generated during HC and LC refining also differs. LC-refined pulps contain thinner fibrillar fines (thread-like) and HC-refined pulps broader fibrils such as lamellae-type fines. Flake-like fines from the outer fiber wall decreased in relative amount with energy input.     

Studies on the effect of prehydrolysis and amine in cooking liquor on producing dissolving pulp from jute (Corchorus capsularis)

Dissolving pulps are the raw materials for the production of many different end-products. Jute is a very good source of cellulose. In this investigation, jute fiber was subjected to pulping in soda process in order to produce dissolving pulp under different prehydrolysis conditions and compared with prehydrolysed kraft pulp from jute. An increase of the prehydrolysis temperature or H₂SO₄ in prehydrolysis liquor increased the α-cellulose content and decreased the viscosity of pulp. The effect of ethylenediamine in soda liquor was also investigated when producing dissolving pulp. Jute fiber produced pulp having 90–97% α-cellulose. Ethylenediamine in soda liquor produced pulp of higher yield, viscosity and higher α-cellulose content than that of prehydrolysis soda or kraft pulp. The α-cellulose content and viscosity were increased with the increase of amine in soda liquor. The kappa number of dissolving pulp from jute was very low (9–5), which indicated that less bleaching chemicals are required for bleaching. The bleachability of soda-ethylenediamine pulp was lower than prehydrolysed soda and kraft pulp in ECF bleaching sequences. The bleachability of soda-ethylenediamine pulp was improved at the sacrifice of pulp yield when prehydrolysis was done prior to pulping. The alkali solubility S ₁₀ and S ₁₈ were 4–9 and 2–4%, respectively.     

Comparison of Quality of Pulping and Paper-Making between Normal Wood and Tension Wood of Poplar Clone 107(Populus×euramericana‘Neva’) Tree

Both of straight and inclining poplar clone 107 tree were selected for studying materials in this paper.The optimal pulping conditions was established by orthogonal experimental design both for normal wood and tension wood,and the quality of pulping and paper-making between normal wood and tension wood was compared with each other. Finally,potential application for improving paper quality of tension wood through increasing beating revolutions was discussed.The result showed that the optimal cooking condition for normal wood was alkali concentration 15%,the highest temperature 164℃,time at highest temperature 75 min,and for tension wood it was alkali concentration 13%,the highest temperature 160℃,time at highest temperature 40 min.Path coefficient of effect of alkali concentration both on pulp yield and kappa value was significant at different levels.By comparison between average result of normal wood and tension wood in quality of pulping and paper-making,it was found that tension wood had higher pulping yield and lower kappa value than normal wood. Furthermore,for all mechanical properties of paper, normal wood hold higher value than tension wood, and even near two times than tension wood,such as burst index and tensile index.However,difference of tear index was quite narrow.Result of one way ANOVA showed that difference of burst index and tear index between normal wood and tension wood was significant at the 0.001 level,of tear index was significant at the 0.05 level.Based on observation of cross surface of paper,it was assumed that contribution of gelatinous layer to rigidity of single fiber had hampered collapse and compression of fiber during paper formation,which is essential for exerting combination between fibers in paper.So, mechanical properties of tension wood paper were decreased accordingly.However,owing to high cellulose content of gelatinous layer,tension wood was easier to pulping than normal wood.Mechanical properties of tension wood paper could be improved by increasing beating revolutions,     

欧美杨107杨正常木与应拉木制浆造纸性能比较

选取直立和倾斜欧美杨107杨为研究材料,根据正交试验确定正常木和应拉木最佳制浆条件,比较正常木和应拉木的制浆造纸性能,通过提高打浆转数对应拉木纸张性能的提高进行探讨。结果表明:正常木的最佳制浆条件为用碱量15%、最高温度164℃、最高温度保温时间75min;而应拉木最佳制浆条件为用碱量13%、最高温度160℃、最高温度保温时间40min。用碱量对正常木和应拉木制浆得率和卡伯值影响的通径系数在不同水平上显著。通过对正常木和应拉木制浆造纸性能比较发现,应拉木比正常木制浆得率高、卡伯值低、纸张力学性能均低,且抗张指数和耐破指数差距较大(约2倍),而撕裂指数差距较小。正常木和应拉木之间卡伯值、制浆得率、抗张指数、耐破指数均在0.001水平上差异显著,撕裂指数在0.05水平上差异显著。结合纸张断口形貌分析认为,胶质层的存在使得应拉木纤维成纸时不容易扁平坍陷,极大地阻碍了成纸时纤维之间的结合,因此降低了纸张力学性能;但是,由于其胶质层纤维素含量很高,因此其制浆性能优于正常木。随着打浆转数的提高,应拉木纸张力学性能增强,且接近正常木纸张水平,但过高会降低纸张力学性能。     

Alkaline pulping with additives. A review

Summary The technology and chemistry of recent advances in alkaline pulping are reviewed from the standpoint of the authors' work over the past few years. Topics reviewed include soda-amine [particularly soda-ethylenediamine (EDA)], soda-anthraquinone (AQ), kraft-AQ, and soda-AQ/EDA pulping and their effects on pulp strength properties and bleachability. There is evidence to support the concept that the rates of all alkaline delignification reactions, including kraft, are controlled by a reductive step which transfers electrons to the degrading lignin.     

Combination treatment of kenaf bast fiber for high viscosity pulp

The viscosity of kenaf bast fiber has been found to be highly sensitive and variable with different pulping methods; therefore, it is important to choose proper chemicals and conditions for pulping and bleaching of kenaf bast fiber. From several pulping experiments, a nonconventional pulping method with a combination of ammonium oxalate pretreatment followed by soda pulping at normal pressure and then acidic chlorite delignification was developed to obtain high-viscosity pulp (162 centipoise). The optimum level of alkali dosage of soda pulping for high-viscosity pulp was found to be 15% (on pulp as NaOH). Pulps showed linear relations between viscosity and xylose or glucose contents, but the combination pulping method gave extremely high pulp viscosity, beyond the relations. The highest viscosity pulp from kenaf bast fiber demonstrated a tear index about twofold and a folding endurance 6.2-fold higher than those of Manila hemp pulp with comparable tensile and burst indexes. The high-viscosity pulp could be used in the production of high-quality currency paper or longevity paper for special uses.Part of this paper was presented at the 43rd Lignin Symposium, Fuchu, Tokyo, October 26–27, 1998     

Selection of plant population of kenaf (Hibiscus cannabinus L.) as a papermaking raw material on arid hillside land in China

Agronomic properties (whole stalk yield, fiber length distribution, chemical composition) and whole stalk kraft pulp characteristics (total pulp yield, pulp fiber length distribution, pulp sheet strengths) were examined for kenaf (variety Zhehong 8310) at four plant populations, ranging from 135 000 to 405 000 plants/ha on arid hillside land at Anji, Zhejiang, China. For agronomic properties, the final whole stalk yield was higher as the plant population increased and as the altitude of the location on the slope decreased. Average fiber lengths of bast and core showed maxima at 225 000 plants/ha. Cellulose content increased as the plant population increased. For the kraft pulp characteristics of kenaf whole stalk, the total pulp yield was lower as the plant population increased, with the maximum difference about 1.3%. Sheet strengths and average fiber length attained maxima at around 225000–315000 plants/ha. The largest pulp strengths (breaking length, burst index, and folding endurance) were seen at a plant population of 225000 plants/ha, and the largest tear index was seen at a plant population of 315 000 plants/ha. When the agronomic properties and whole stalk kraft pulp characteristics were combined, a plant population between 225 000 and 315 000 plants/ha, which is a little higher than that of kenaf bast production for textiles, was selected as the optimum cultivated kenaf plant population for whole stalk kraft pulp and papermaking on arid hillside land in China.