Fibre characteristics and paper properties of formic acid / peroxyformic acid birch pulps

1997 ◽  
Vol 12 (4) ◽  
pp. 237-243 ◽  
Author(s):  
Anu Seisto ◽  
Krisriina Poppius-Levlin
Keyword(s):  
Tensile Strength ◽  
Formic Acid ◽  
Kraft Pulp ◽  
Strength Properties ◽  
Kappa Number ◽  
Strength Development ◽  
Paper Properties ◽  
Fibre Breakage ◽  
High Degree ◽  
Peroxyformic Acid

Abstract The fibre and paper properties of nine unbleached formic acid / peroxyformic acid (MILOX) pulps with kappa number 6-20 were studied and compared with a kraft pulp with kappa number 20. The degree of deformation was greater in the MILOX fibres, affecting the paper properties of the MILOX pulps. The large number of curl and kinks in the MILOX fibres were probably caused mechanically. The MILOX fibres showed greater conformability, resulting in higher paper density. The defects in the MILOX fibres were apparently so severe as to cause fibre breakage during PFI beating of the pulps. As a result of both fibre deformation and breakage, the tensile strengths of the MILOX pulps were lower than that of the reference kraft pulp, and tensile strength development during beating was slower. The tear strength of the best MILOX pulp was lower than that of the kraft pulp when compared at the same tensile index. Fibre deformation in both MILOX and the kraft pulp increased during bleaching. The kinks in the fibres were possibly set into position, giving the bleached MILOX pulps poorer bonding ability and lower paper density. A high degree of fibre defo~mation had the same effect on the tensile strength development of the bleached MILOX pulps as it did in the unbleached state. The light scattering properties of the MlLOX pulps were better than those of the kraft pulp, possibly due to the higher fines content of the MILOX pulps. The results indicate that more attention should be given to mechanical treatments during MILOX pulping in order to bring the strength properties closer to those of kraft pulp.

scholarly journals Softwood kraft pulp fines: application and impact on specific refining energy and strength properties

Cellulose ◽  
2020 ◽  
Vol 27 (17) ◽  
pp. 10359-10367
Author(s):  
Daniel Mandlez ◽  
Lukas Zangl-Jagiello ◽  
Rene Eckhart ◽  
Wolfgang Bauer
Keyword(s):  
Tensile Strength ◽  
Linear Relationship ◽  
Apparent Density ◽  
Kraft Pulp ◽  
Strength Properties ◽  
Air Permeability ◽  
Research Interest ◽  
Paper Properties ◽  
Softwood Kraft Pulp ◽  
Breaking Length

AbstractAlong with the emergence of micro and nanofibrillated celluloses and their application in papermaking, the influence of the so called fines fraction of pulps on both process and product properties has received increasing research interest in recent years. Several researchers have experimented with primary and/or secondary pulp fines to assess their effects on paper properties with not always consistent results. Our work focuses on the targeted application of the primary fines fraction of an unbleached softwood kraft pulp. The primary fines are separated from the pulp to be subsequently added to achieve blends of $$5\%, 9\%$$ 5 % , 9 % and $$12\%$$ 12 % primary fines content. These blends were then refined in a PFI mill to evaluate the effect of the primary fines on refining as well as on paper properties of hand sheets prepared from these pulps. It is shown that the addition of primary fines enhances tensile strength in the unrefined and slightly refined state, while the maximum tensile strength of the highly refined reference pulp is not increased. A slightly increased dewatering resistance (Schopper Riegler) at comparable air permeability (Gurley) for a given tensile strength was also observed. The linear relationship between tensile index and apparent sheet density seems to be affected in the unrefined and slightly refined state where the breaking length of the fines enriched samples is higher for a given apparent density.

Effect of machine speed on formation and strength efficiency in twin-wire roll forming of never-dried unbleached softwood kraft pulp

2018 ◽  
Vol 33 (2) ◽  
pp. 271-278
Author(s):  
Bengt Nordström ◽  
Lennart Hermansson
Keyword(s):  
Tensile Strength ◽  
Kraft Pulp ◽  
Roll Forming ◽  
Favorable Effect ◽  
Paper Properties ◽  
Difference Curve ◽  
Insignificant Effect ◽  
Wide Range ◽  
Softwood Kraft Pulp ◽  
Machine Speed

Abstract There is a constant drive to increase machine speed in the production of kraftliner and most other major paper grades, but the separate effect of the machine speed on the paper properties has been unclear. The effect of machine speed in twin-wire roll forming of never-dried unbleached softwood kraft pulp was evaluated here in a pilot machine investigation by examining three machine speed levels (500, 750, and 1000 m/min) over a series of jet-to-wire speed differences. Similar headbox consistency and draw from wire section to winding were employed at the different machine speed levels. An increase in the machine speed had a favorable effect on formation and Z-strength efficiency over a wide range of jet-to-wire speed differences, whereas the machine speed had an insignificant effect on tensile strength efficiency and tensile stiffness efficiency. For all properties, the overall shape of the jet-to-wire speed difference curve remained similar when changing the machine speed.

scholarly journals Formic Acid Pulping of Bagasse

1970 ◽  
Vol 41 (3) ◽  
pp. 245-250 ◽  
Author(s):  
M Sarwar Jahan
Keyword(s):  
Formic Acid ◽  
Acid Concentration ◽  
Strength Properties ◽  
Kappa Number ◽  
Cooking Time ◽  
Pulp Yield ◽  
Cooking Conditions

Atmospheric formic acid pulping of bagasse was done with varying formic acid concentration and cooking time. Pulp yield and kappa number decreased with increasing formic acid concentration or cooking time. The optimal cooking conditions were 90 % formic acid and 90 min of cooking at 95°C. The pulp yield at this condition was 44.4 % and kappa number 26.1. The strength properties were acceptable in formic acid pulping of bagasse. Addition of H2SO4 catalyst in formic acid degraded carbohydrate, resulting lower pulp yield and inferior strength properties. The strength properties were improved slightly after bleaching. Bangladesh J. Sci. Ind. Res. 41(3-4), 245-250, 2006

Enhancement of eucalypt pulp yield through extended impregnation cooking

2018 ◽  
Vol 33 (2) ◽  
pp. 175-185 ◽  
Author(s):  
Gustavo B. de Souza ◽  
Jorge Luiz Colodette ◽  
Fernando José Borges Gomes ◽  
Danila Morais de Carvalho
Keyword(s):  
Chlorine Dioxide ◽  
Kraft Pulp ◽  
Strength Properties ◽  
Kraft Pulping ◽  
Kappa Number ◽  
Pulp Yield

AbstractThe improvement caused by eucalypt chip impregnation on kraft pulping performance was assessed for terminating the cook at kappa in the range of 15–27 and at controlled residual effective alkali (REA) of 6–8 g/L NaOH. Extended impregnation cooking of eucalypt chips (EIC) increased about 1 %lignin- and HexA-freescreen yield gains in relation to conventional cooking (CC), regardless of kappa number in the range of 15–27. The EIC technology allows for cooking eucalypt wood to kappa number up to 27, without rejects production, but without significant improvement inlignin- and HexA-freescreen yield and with larger chlorine dioxide (ClO2) consume during bleaching. The optimum kappa number for both CC and EIC cooking was about 19 with similar refinability and strength properties for both technologies, CC and EIC. It was concluded that extended impregnation cooking is an attractive technique for enhancing bleached eucalypt Kraft pulp yield.

Tear and tensile strength development of PGW and CTMP pulps mixed with PLA or viscose fibres

2014 ◽  
Vol 29 (2) ◽  
pp. 304-308 ◽  
Author(s):  
Jaakko Asikainen ◽  
Antti Korpela
Keyword(s):  
Tensile Strength ◽  
Fibre Length ◽  
Wood Fibre ◽  
Strength Development ◽  
Paper Properties ◽  
Mechanical Pulp ◽  
Tear Strength ◽  
Tear Index ◽  
Simultaneous Decrease ◽  
A Minor

Abstract The objective was to evaluate the effects on paper properties when replacing a minor share of wood fibre by synthetic fibre. The aim was to increase tear strength and stretch while minimizing the loss of tensile strength in paper consisting of mechanical pulp. Tested synthetic fibres included PLA and viscose fibres mixed with mechanical or chemi-mechanical pulp. Even at relatively low proportions, the synthetic fibres contributed to a significant increase of tear strength in the wood fibre based papers. With the highest tested proportion (20%) the increase of tear index in PGW based stock was 243% with PLA and 177% with viscose fibre. However, a simultaneous decrease in tensile strength and tensile stiffness was observed. The stretch at break remained unchanged. Thickness reduction of the synthetic fibres resulted in an increase of tear strength. The effect is due to the high fibre length of synthetic fibres, producing mechanically well entangled networks, coupled with the high enough strength of the synthetic fibres.

Formic Acid-Peroxyformic Acid Pulping of Aspen Wood: An Optimization Study

Holzforschung ◽  
2000 ◽  
Vol 54 (5) ◽  
pp. 544-552 ◽  
Author(s):  
S. Abad ◽  
V. Santos ◽  
J. C. Parajó
Keyword(s):  
Formic Acid ◽  
Populus Tremuloides ◽  
Kappa Number ◽  
Pulp Yield ◽  
Aspen Wood ◽  
Acid Media ◽  
Optimization Study ◽  
Operational Variables ◽  
Alkaline Resistance ◽  
Peroxyformic Acid

Summary Populus tremula* Populus tremuloides wood samples were subjected to three-stage pulping in formic acid media with hydrogen peroxide addition, according to the Milox process. By means of three incomplete, second-order, centered, factorial designs, the effects of selected operational variables on the composition and technical properties of pulps were assessed for optimization purposes. Under the best conditions assayed, a pulp with 2.30% lignin, 87.0 % cellulose and 3.25% xylan was obtained at 53.2% pulp yield. Good SCAN viscosity (826 ml/g), reduced Kappa number (9.0) and satisfactory alkaline resistance (R-10 = 89.0; R-18 = 91.0) proved the potentiality of the selected pulp for dissolving pulp production.

scholarly journals Bleached kraft pulp production from Pinus tecunumanii (Eguiluz e Perry)

2005 ◽  
Vol 29 (3) ◽  
pp. 489-494 ◽  
Author(s):  
Leonel F. Torres ◽  
Roberto Melo ◽  
Jorge Luiz Colodette
Keyword(s):  
Kraft Pulp ◽  
Strength Properties ◽  
Kappa Number ◽  
Raw Material ◽  
Kraft Pulps ◽  
Optimum Conditions ◽  
Oxygen Delignification ◽  
Bleached Kraft Pulp ◽  
Pinus Tecunumanii ◽  
Pulp Production

The use of 12-year-old Pinus tecunumanii (Eguiluz e Perry) grown in Colombia was evaluated for bleached kraft pulp production. Kraft pulps of kappa number 30 ± 1 were produced, and oxygen delignified and bleached to 90% ISO with ECF processes. The bleached pulps produced under optimum conditions were evaluated with regard to their strength properties. Pinus tecunumanii wood required low effective alkali charge to reach the desired kappa number and the unbleached pulp showed high oxygen delignification efficiency and bleachability when a OD(EO)DED sequence was used. The bleached pulps presented good physical-mechanical properties, which are comparable to those obtained with more traditional pines such as Pinus taeda and Pinus radiata. The results demonstrate that this tropical pine species is a suitable raw material for bleached kraft pulp production

scholarly journals Comparison of two bar edge lengths of refining plates on the properties of American old corrugated container pulp during low consistency refining

BioResources ◽  
2019 ◽  
Vol 15 (1) ◽  
pp. 347-359
Author(s):  
Hui Cai ◽  
Zhaoyang Yuan ◽  
Guolin Tong ◽  
Xin Zhang ◽  
Hui Zhang
Keyword(s):  
Tensile Strength ◽  
Specific Energy ◽  
Lower Energy ◽  
Energy Input ◽  
Fibre Length ◽  
Strength Properties ◽  
Strength Development ◽  
Low Intensity ◽  
Plate Geometry ◽  
Length Reduction

Commercial American old corrugated container pulp (AOCC) boards were used as the starting material for repulping and low consistency (LC) refining to investigate the effects of LC refining plate geometry on the fibre and strength properties of the generated pulp. Specific refining energy that ranged from 0 to 120 kWh/air-dried ton (ADT) of pulp was explored for the two bar edge lengths (BEL) of refining plate patterns, wide 0.99 km/rev BEL and interim 2.01 km/rev BEL. The results showed that fibre length, curl index, kink index, and pulp freeness decreased while fines content increased with increasing refining energy input for both of the two refining plates during LC refining. LC refining with 2.01 BEL plate at low intensity of 0.24 J/m showed less fibre length reduction and more tensile strength development than that obtained with 0.99 BEL plate at high intensity of 0.48 J/m when compared at the same specific energy. Moreover, to achieve the desired tensile strength of the AOCC pulp, lower energy was needed for the interim 2.01 BEL plate than the wide 0.99 BEL plate. Thus, the interim 2.01 km/rev BEL refining plate provided potential for saving refining energy to reach a desired tensile strength of AOCC pulp.

scholarly journals Hydrogen peroxide bleaching of hardwood kraft pulp with adsorbed birch xylan and its effect on paper properties

BioResources ◽  
2011 ◽  
Vol 6 (1) ◽  
pp. 721-736
Author(s):  
Lizi Li ◽  
Sanghoon Lee ◽  
Hak Lae Lee ◽  
Hye Jung Youn
Keyword(s):  
Hydrogen Peroxide ◽  
Optical Properties ◽  
Kraft Pulp ◽  
Strength Properties ◽  
Pulp Fibers ◽  
Paper Properties ◽  
Peroxide Bleaching ◽  
Initial Ph ◽  
The Relationship ◽  
Temperature Time

The adsorption of xylan on pulp fibers improves the strength properties of paper. However, the optical properties are decreased significantly. The objective of our research was to bleach hardwood kraft pulp with adsorbed birch xylan by hydrogen peroxide and study the effect of bleaching parameters on paper properties. The bleaching parameters studied included bleaching temperature, time, initial pH as well as MgSO4 dosage. The optical properties (whiteness, brightness, opacity) and physical properties (tensile index, tearing index, bulk) of handsheets made from the pulp bleached with different process variables were measured. The results showed that better optical properties were obtained with higher bleaching temperature, longer bleaching time, and more MgSO4 dosage. Bleaching from an initial pH of 11 provided the highest brightness value. On the other hand, strength properties were improved with decreasing of the bleaching temperature, and increasing the initial pH and MgSO4 dosage. The relationship between strength properties and bleaching time varied depending on bleaching temperature. According to the results, both good mechanical properties and optical properties could be achieved when the operating parameters were controlled properly. Therefore hydrogen peroxide bleaching was proved to be a suitable method for bleaching hardwood kraft pulp with adsorption of birch xylan.

Enzymatic bleaching of eucalyptus kraft pulp: effects on the prebleaching filtrate, pulp quality and paper properties

Holzforschung ◽  
2013 ◽  
Vol 67 (2) ◽  
pp. 147-153 ◽  
Author(s):  
Maria Tereza Borges ◽  
Claudio Mudado Silva ◽  
Jorge Luiz Colodette ◽  
Rubens Chaves de Oliveira ◽  
Flavio Tesser
Keyword(s):  
Physical Properties ◽  
Kraft Pulp ◽  
Oxygen Demand ◽  
Kappa Number ◽  
Pulp Yield ◽  
Paper Properties ◽  
Eucalyptus Kraft Pulp ◽  
Mechanical And Physical Properties ◽  
Hexenuronic Acid

Abstract Enzymatic bleaching appears to be a promising approach for clean bleaching processes and the reduction of bleaching chemical consumption. In this work, the quality of the filtrates and the pulps has been characterized after enzymatic prebleaching stages of eucalyptus kraft pulp. Four different conditions with xylanase were investigated. Following each prebleaching stage, the properties of the pulp [kappa number, brightness, content of hexenuronic acid (HexA), xylan removal, and pulp yield lost], and of the resulting effluents (chemical oxygen demand (COD), biochemical oxygen demand (BOD), color, and conductivity) were determined. In addition, a complete bleaching sequence was performed to characterize the pulp quality at the end of the sequence. Finally, the pulp was refined in a PFI mill, and the mechanical and physical properties of the resulting paper were determined. The best pulp quality was achieved at pH 7, at which a lower kappa number, higher pulp brightness, and smaller amount of HexA were observed. Under this condition, however, a larger yield loss and a higher effluent COD load had to be accepted. After the complete bleaching sequence, the enzymatic treatments yielded pulps with higher brightness and viscosity as well as with a lower kappa number. The enzymatic treatments resulted in small changes in the mechanical and physical properties of the paper handsheets produced.

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