Multiple recycling of paperboard: Paperboard characteristics and maximum number of recycling cycles— Part I: Multiple recycling of corrugated base paper

Paper for recycling is an important fiber source for the production of corrugated base paper. The change in production capacity toward more and more packaging papers affects the composition of paper for recycling and influences the paper quality. This research project investigated the influence of the multiple recycling of five different corrugated base papers (kraftliner, neutral sulfite semichemical [NSSC] fluting, corrugating medium, testliner 2, and testliner 3) on suspension and strength properties under laboratory conditions. The corrugated board base papers were repulped in a low consistency pulper and processed into Rapid-Köthen laboratory sheets. The sheets were then recycled up to 15 times in the same process. In each cycle, the suspension and the paper properties were recorded. In particular, the focus was on corrugated board-specific parameters, such as short-span compression test, ring crush test, corrugating medium test, and burst. The study results indicate how multiple recycling under laboratory conditions affects fiber and paper properties.

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Prediction of box failure from paper data for asymmetric corrugated board

TAPPI Journal ◽

10.32964/tj17.08.429 ◽

2018 ◽

Vol 17 (08) ◽

pp. 429-434 ◽

Cited By ~ 2

Author(s):

Heinz Joachim Schaffrath ◽

Felix Reichenbach ◽

Samuel Schabel

Keyword(s):

Compression Test ◽

Elastic Moduli ◽

Bending Stiffness ◽

Machine Direction ◽

Paper Properties ◽

Cross Direction ◽

Corrugated Board ◽

Influencing Parameters ◽

Theoretical Considerations

The well-known McKee formula was derived in 1963 for symmetric fluting constructions. This paper presents investigations showing the influence of asymmetric properties, either geometric or concerning the elastic moduli. Paper properties of the base papers used are taken to calculate the panel properties of corrugated boards. From these results, the box failure is predicted. To do this, a model approximating the corrugated medium by triangles is presented. With this assumption, the bending stiffness of corrugated board, no matter how many flutes, can be predicted from paper data. Machine direction and cross direction are treated separately. The theoretical considerations are verified by measuring paper parameters such as short compression test (SCT), thickness, and bending stiffness, as well as edge compression test (ECT) and bending stiffness of corrugated board and box compression test (BCT) of the boxes. It can be stated that the prediction of using paper data instead of corrugated board data may lead to even better prediction results, as the measuring of bending stiffness at the board may sometimes be influenced by sampling inconveniences. Finally, thickness of the used base papers, as well as thickness of the manufactured board, appear to be the main influencing parameters. The McKee formula is robust enough to be applied for asymmetric corrugated board as well.

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SEM Study of Tension Wood Fiber Morphology and its Effect on Paper Properties

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100079061 ◽

1977 ◽

Vol 35 ◽

pp. 308-309

Author(s):

K. W. Robinson

Keyword(s):

Tension Wood ◽

Wood Fiber ◽

Strength Properties ◽

Fiber Morphology ◽

Paper Properties ◽

Pure Cellulose ◽

Short Rotation ◽

Hardwood Trees ◽

Sem Study

Tension wood (TW) is an abnormal tissue of hardwood trees; although it has been isolated from most parts of the tree, it is frequently found on the upper side of branches and leaning stems. TW has been classically associated with geotropic alignment, but more recently it has been associated with fast growth. Paper made from TW is generally lower in strength properties. Consequently, the paper industries' growing dependence on fast growing, short- rotation trees will result in higher amounts of TW in the final product and a corresponding reduction in strength.Relatively few studies have dealt with the role of TW in the structure of paper. It was suggested that the lower strength properties of TW were due to a combination of factors, namely, its unique morphology, compression failures in the cell wall, and lower hemicellulose content. Central to the unique morphology of the TW fiber is the thick gelatinous layer (G-layer) composed almost entirely of pure cellulose.

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Does kraft hardwood and softwood pulp viscosity correlate to paper properties?

TAPPI Journal ◽

10.32964/tj15.10.643 ◽

2016 ◽

Vol 15 (10) ◽

pp. 643-651 ◽

Cited By ~ 1

Author(s):

ROBERT J. OGLESBY ◽

HUMPHREY J. MOYNIHAN ◽

RICARDO B. SANTOS ◽

ASHOK GHOSH ◽

PETER W. HART

Keyword(s):

Physical Properties ◽

Strength Loss ◽

Strength Properties ◽

Clear Correlation ◽

Paper Properties ◽

Physical Strength ◽

Pulp Viscosity ◽

Softwood Pulp ◽

The Impact ◽

On the determination of transverse shear properties of paper using the short span compression test

Mechanics of Materials ◽

10.1016/j.mechmat.2017.01.012 ◽

2017 ◽

Vol 107 ◽

pp. 22-30 ◽

Cited By ~ 6

Author(s):

P. Hämäläinen ◽

N. Hallbäck ◽

A. Gåård ◽

M. Lestelius

Keyword(s):

Compression Test ◽

Transverse Shear ◽

Shear Properties ◽

Short Span

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Cellulose fiber enzymatic modification to improve the softness, strength, and absorption properties of tissue papers

BioResources ◽

10.15376/biores.16.1.846-861 ◽

2020 ◽

Vol 16 (1) ◽

pp. 846-861

Author(s):

Flávia P. Morais ◽

Ana M. M. S. Carta ◽

Maria E. Amaral ◽

Joana M. R. Curto

Keyword(s):

Fiber Type ◽

Capillary Rise ◽

Reaction Times ◽

Cellulose Fiber ◽

Strength Properties ◽

Enzymatic Modification ◽

Absorption Properties ◽

Paper Properties ◽

Tissue Properties ◽

Tissue Paper

Effects of enzymatic modification were evaluated in bleached Eucalyptus kraft and sulfite cellulosic pulps, separately, to improve key tissue paper properties and design new Eucalyptus fiber applications. Different cellulase dosages (0.01 mg and 0.1 mg of enzyme/g of pulp) and reaction times (30 min and 60 min) were used to modify the fibers and replace the traditional mechanical based refining or beating process. The results showed that for enzymatic modified kraft and sulfite pulps, the softness properties were improved by 1 and 2 units, respectively, for each unit of decreased strength properties. To achieve a balance between the tissue properties, the different fiber pulp furnishes that contained 80% of the enzymatically treated kraft pulp and 20% of the sulfite pulp with and without enzymatic treatment, were studied. Overall, the structures made with these mixtures presented softness properties in the commercial range (57.8 to 74.4), improved absorption properties (107 mm to 120 mm of capillary rise), and good strength properties (13.0 to 17.7 N.m/g). This study was conducted in order to adjust the fiber furnishes according to industrial tissue standards, using one Eucalyptus fiber type providing strength and another providing softness.

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Study of the mechanical behavior of recycled fibers. Applications to papers and paperboards.

10.31237/osf.io/46w8m ◽

2018 ◽

Author(s):

Imtiaz Ali

Keyword(s):

Surface Friction ◽

Strength Properties ◽

Size Exclusion ◽

Ultrastructural Changes ◽

X Rays ◽

Paper Strength ◽

Electron Microscopic ◽

Paper Properties ◽

Recycled Pulp ◽

Fibre Width

Incorporation of recycled fibres in high value paper products can reduce cost and environmental loads. Papermaking potential of cellulosic fibres decreases with recycling. The phenomenon of fibre hornification during pressing and drying is normally held responsible for the loss in strength. To study the impacts of recycling on pulp, fibre and paper properties some non conventional characterisation techniques like fibre saturation point, X-rays microtomography, environmental scanning electron microscopic observations, atomic forcemicroscope (PeakForce QNM mode) and inverse size exclusion chromatography(ISEC) were used. In order to achieve good reproducibility of ISEC measurements,a semi-automatic column fabrication pilot system was built. The techniques were first validated on refining process before being applied to the recycling process. In this study, it was found that fibre hornification alone cannot fully explain loss in strength during recycling. The loss in strength is much more complex and it is required to understand the morphological and ultrastructural changes associated with recycling. Fibre width, cell wall thickness,curl, kink, irregularities decreased during recycling. Fibre became hard and brittle in dry state. Number of weak points in the fibre wall were increased initially and in the later recyclings. The increase in wet breaking length indicates increased surface friction and capillary forces with recycling. Decrease in bonded area during first recycle may be caused by the loss of fines and fibre flexibility whereas the increase afterwards may be linked to the lumen collapse.The strength of fibres did not decrease with recycling as shown by zero-span breaking lengths therefore the quality of bond may be deteriorated. It was thought that the partially delaminated P/S1 layers may be responsible for the loss of paper strength. It is suggested since the significant change is associated with the pressing and drying of never dried pulp therefore the drying process needs to be revisited. The delaminated layer should be restored so as to increase the recyclability of the recovered fibres for high value paper. Influence of recycled pulp blends on physical properties of paper was also studied. It was revealed that small quantity of recycled pulp can be used without significantly affecting the mechanical strength properties.

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De-esterification and sulfonation in spruce CTMP: Effects on pulp and paper properties

Holzforschung ◽

10.1515/hf.2006.056 ◽

2006 ◽

Vol 60 (4) ◽

pp. 355-364 ◽

Cited By ~ 2

Author(s):

Jonas Konn ◽

Lari Vähäsalo ◽

Andrey Pranovich ◽

Bjarne Holmbom

Keyword(s):

Chemical Reactions ◽

Energy Demand ◽

Fibre Length ◽

Middle Lamella ◽

Strength Properties ◽

Pulp And Paper ◽

Paper Properties ◽

Alkaline Peroxide ◽

Chemithermomechanical Pulping ◽

Hydrolysis Of

Abstract De-esterification and sulfonation reactions, which create new anionic groups in the middle lamella and primary wall layers, are the key chemical reactions in chemithermomechanical pulping. The effects of these reactions on the resulting fibre dimensions, refining energy demand, hand-sheet bulk and strength properties were assessed by laboratory-scale chemical pre-treatments and refining of Norway spruce chips. After pre-treatments with alkaline, sulfite, alkaline sulfite and alkaline peroxide liquors, a Wing defibrator-type batch refiner was used. The refining energy was measured. The degree of alkaline hydrolysis of acetyl and methyl ester groups in galactoglucomannans (GGMs) and pectins, and the degree of lignin sulfonation were determined. Hand-sheets were prepared and their physical properties were tested. The data were subjected to multivariate analysis and the order of significance of the chemical reactions towards pulp and paper properties was estimated. Chemical pre-treatments were found to increase the fibre length and the energy demand considerably. The fibre length and width after refining were strongly influenced by lignin sulfonation and pectin demethylation. GGM deacetylation had little influence on preserving the fibre dimensions in CTMP refining. The bulk, on the other hand, was highly influenced by GGM deacetylation. Peroxide reactions in alkaline peroxide treatments had no effect on the pulp and paper properties.

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Flyash Based Paper Slurry Building Bricks– an Experimental Approach

International Research Journal of Multidisciplinary Technovation ◽

10.34256/irjmtcon44 ◽

2019 ◽

pp. 334-341

Author(s):

Malathy R ◽

Jegatheeswaran D

Keyword(s):

Water Absorption ◽

Compression Test ◽

Experimental Approach ◽

Ultimate Load ◽

Strength Properties ◽

Absorption Test ◽

Coating Agent ◽

Water Absorption Test ◽

Percentage Of Water Absorption ◽

External Coating

This paper deals with the investigation carried out to study the Strength Properties of Papercrete Building Bricks and these results were compared with conventional bricks. The papercrete brick did not fully collapse even at ultimate load and it never failed catastrophically. Hence the outer faces got cracked and peeled out. From the observation of the compression test, it is inferred that the papercrete bricks are having less elastic and are less brittle. Water absorption test was carried out as per the guidelines given in ASTM C-642. After coated with an external coating agent, the percentage of water absorption of the papercrete bricks was nearly the same as the conventional bricks. Also young’s modulus and poisson’s ratio of coated papercrete bricks was determined.

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Validity of Shunt Pumping Test as a Screening Modality for Shunt Block: An Experimental Study

Indian Journal of Neurosurgery ◽

10.1055/s-0040-1708572 ◽

2020 ◽

Vol 09 (01) ◽

pp. 35-41

Author(s):

Manish Sharma ◽

Suman Kumar

Keyword(s):

Likelihood Ratio ◽

Compression Test ◽

Odds Ratio ◽

Positive Likelihood Ratio ◽

Negative Likelihood Ratio ◽

Pumping Test ◽

Diagnostic Ability ◽

Predicted Probability ◽

Predictive Probability ◽

Study Results

Abstract Purpose To ascertain the validity and efficacy of shunt compression test in evaluating a blocked shunt. Methods An experimental model was created using a Chhabra shunt, and 25 physicians with 1 to 3 years of experience in neurosurgery were asked to assess the block in the model where artificial blocks were created. Results The sensitivity of test to detect any block was found to be 0.76 (95% confidence interval [CI]: 0.7–0.81), specificity was 0.71 (0.59–0.81), positive likelihood ratio 2.59 (1.81–3.7), and negative likelihood ratio 0.34 (026–0.45). Odds ratio for proximal block was 4.33 (95% CI: 2.01–8.92), and for distal block, it was 10.63 (95% CI: 10.63–22.32). Furthermore, predictive probability for shunt block was maximum when both the ends were considered to be blocked by the investigator and the test was found to be poor in predicting a patent shunt. Conclusion This is not a very reliable screening test to detect presence of a shunt block. Predicted probability for shunt block was maximum when both the ends were considered to be blocked by the investigator. This study results are not in conformity with the previously held belief that delayed refilling of chamber would clearly aid the diagnosis of proximal end block. It is strongly felt that a deliberate training of shunt compression test would aid a better diagnostic ability.

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Schwedler Single-Layer Ellipsoid Reticulated Shell Static Stability Analysis of Influencing Factors

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.368-373.637 ◽

2011 ◽

Vol 368-373 ◽

pp. 637-640

Author(s):

Ru Wang ◽

Li Nan Xie ◽

Hu Chang

Keyword(s):

Theoretical Basis ◽

Single Layer ◽

Static Stability ◽

Engineering Practice ◽

Asymmetric Distribution ◽

Analysis Software ◽

Buckling Mode ◽

Study Results ◽

Short Span ◽

Geometric Nonlinear Analysis

Proceeding eigenvalue buckling analysis and geometric nonlinear analysis on schwedler single-layer ellipsoid reticulated shell with analysis software ANSYS, obtain structural buckling mode and ultimate bearing capacity at different short span and different rise-span ratio. Then analyze its impact on static stability of ellipsoid reticulated shell considering load asymmetric distribution and initial defect, conclude stability regular of schwedler single-layer ellipsoid reticulated shell. These study results can provide theoretical basis and technical reference for further studying on static stability of schwedler single-layer ellipsoid reticulated shell and engineering practice.

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