Pulp and Paper Research Institute

Bratislava, Slovakia

Pulp and Paper Research Institute

Bratislava, Slovakia
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Gigac J.,Pulp and Paper Research Institute | Stankovska M.,Pulp and Paper Research Institute | Pazitny A.,Pulp and Paper Research Institute
Wood Research | Year: 2016

At the coating were used two substrates, commercial base paper and base paper produced in pilot experimental paper machine. The printing quality varied at both base papers. The coating colours contain commercial silica and precipitated calcium carbonate pigments. As a binder was used polyvinyl alcohol and cationic starch combined with high-cationic polymer SMAI 1000. Colour gamut significantly improved when the inkjet ink contact angle decreased below 14° independently of the base paper. The order of coating colours effect on the base papers was similar. Application of silica pigment in the coating colour provided papers with the largest inkjet ink wetting, the best colour gamut area, print sharpness and smoothness. By using of polyvinyl alcohol, a high colour gamut area was reached but it resulted in a markedly low print sharpness in comparison with cationic starch. Coating of base paper produced in pilot experimental paper machine introduces papers with higher colour gamut and also print sharpness. © 2016, Statny Drevarsky Vyskumny Ustav. All rights reserved.


Fiserova M.,Pulp and Paper Research Institute | Opalena E.,Pulp and Paper Research Institute | Maholanyiova M.,Pulp and Paper Research Institute
Cellulose Chemistry and Technology | Year: 2013

Beech wood chips were extracted with green kraft liquor at different alkali charges of 1, 2, 3 and 4% on dry wood mass and with hot water. The extractions were performed at 160 °C and different time to achieve 10% wood mass loss. The total content of monosugars in hydrolysed extracts decreased with increasing green liquor charge, but lignin and insoluble solids content increased. The kraft pulp yields from pre-extracted chips with 2, 3 and 4% green liquor charge were similar with those from original wood chips. Effective alkali charges in the pulping process were about 1% to 3.5% lower than in control kraft pulping and reduced with increasing green liquor charge in the extraction process. The addition of AQ in the extraction or pulping process increased pulp yield, especially in extraction. Limiting viscosity numbers of the pulps from chips pre-extracted with green liquor were slightly higher than those of control kraft pulps. Tensile, burst and tear strength of the pulp handsheets from chips pre-extracted with 2, 3 and 4% green liquor charge were the same as or slightly higher than those for original wood chips. The optimal green liquor charge in the extraction process was 2% or 3%, in terms of extraction and pulping process effectiveness.


Fiserova M.,Pulp and Paper Research Institute | Opalena E.,Pulp and Paper Research Institute
Wood Research | Year: 2012

Beech wood chips were treated with water and water solutions of alkaline chemicals at elevated temperature in order to extract a part of hemicelluloses. The extractions were performed at 160°C, chemicals charge 3% Na2O on o.d. wood; H-factor was changed in the range from O to 850 hrs. Dissolution rate of wood components was highest in case of extraction with water followed by extraction with NaOH solution, green liquor (GL), sodium acetate (NaAc), NaHCO3 and Na2CO3. With increasing H-factor pH of extracts decreased; highest decrease was in extraction with water followed by extraction with solutions of NaAc, NaOH, GL, Na2CO3and NaHCO3. At of 10% wood weight loss pH of extract decreased in extraction with water to 3.9 whereas in extraction with NaAc to pH 5.1, with NaOH to 5.5, Na2CO3to 5.6, with GL to 6.4 and with NaHCO3 to pH 6.6. Under these conditions the total content of sugars in the hydrolysed extract after extraction with water was 6.1% on o.d. wood; out of this xylose content was 4.6% on o. d. wood. In extraction with solutions of NaOH, GL, NaAc, NaHCO3, Na2CO3the total content of sugars was in the range 2.05 to 3.3% on o.d. wood and xylose content was 1.85 to 2.85% on o.d. wood. In extraction with alkaline solutions glucose content in hydrolysed extracts was 0.24 to 0.34% on o.d. wood, what is approximately by half lower than in extraction with water. Lignin content in extracts was 0.8% to 1.2% on o.d. wood; insoluble solids content was in the range 0.55% to 1.8% on o.d. wood.


Fiserova M.,Pulp and Paper Research Institute | Opalena E.,Pulp and Paper Research Institute | Illa A.,Pulp and Paper Research Institute
Wood Research | Year: 2013

Combination of pre-extraction with kraft pulping was applied to beech chips in order to use hemicelluloses for biofuels or chemicals production. The extraction with hot water and dilute oxalic acid solutions was performed at 160°C. The oxalic acid increased the rate of extraction by a factor of 2 to 3.2. The content of total monosugars, xylose and glucose in hydrolysed extracts was higher while the content of lignin and insoluble solids in extracts was lower compared to hot water extract. At the same kappa number the pulp yield from pre-extracted chips was lower in comparison with the control pulp. The pulp yield decreased with increase of extracted wood, at Kappa number 20 and 5% wood weight loss the yield decreased by 2.5 to 5%, at 10% wood weight loss by 7 to 11.5%. The effective alkali charges in the pulping process of pre-extracted chips were by 0.5 to 1% lower than in the control pulping. The pulp strength properties from pre-extracted pulps were lower compared to the control pulp. The tensile index of pulps from pre-extracted chips with 5% wood weight loss decreased by 4 to 8.5%, with 10% wood weight loss by 10 to 16% in comparison with control pulps at the same kappa number. The tear index of pulps from pre-extracted wood decreased similarly. Pre-extraction of beech wood with lower concentration of oxalic acid (0.0825%) is preferable to hot water pre-extraction because the kraft pulp yield and strength properties are higher at the same wood weight loss.


Gigac J.,Pulp and Paper Research Institute | Fiserova M.,Pulp and Paper Research Institute
Cellulose Chemistry and Technology | Year: 2010

The influence of velocity gradient on the anisotropy of tensile stiffness index, tensile energy absorbance, tensile index, tear strength, tensile stiffness orientation, formation and curl of MG paper, as well as on the anisotropy of coating raw paper, was investigated. The maximum strength of MG paper was achieved in the 0.93-1.05 range of the jet-to-wire speed ratio. The best formation and the lowest curl with fibre orientation ±1.7° was achieved at a jet-to-wire speed ratio around 1.0, while CMT and SCT of fluting from a mixture of semi-chemical pulp and recovered fibres produced at a constant speed difference of the jet and wire are influenced by basis weight and semi-chemical pulp content.


Fischer R.,Pulp and Paper Research Institute | Fiserova M.,Pulp and Paper Research Institute
Arkivoc | Year: 2015

A regioselective monoamidation of furan-2,5-dicarboxylic acid using O-(benzotriazol-1-yl)-N,N,N′,N′-tetramethyluronium tetrafluoroborate is presented. The excellent regioselectivity in favour of activated monobenzotriazoyl ester as a intermediate is achieved by gradual addition of a coupling reagent into a dilute solution of furan-2,5-dicarboxylic acid and N,Ndiisopropylethylamine in dimethylformamide. Divided crude reaction mixture is used directly in the subsequent coupling reactions with benzylamine, diethylamine, piperidine and aniline, respectively. Four representative monoamides are prepared and isolated in very good yields 73- 82%. Traces of symmetric diamides were also detected, however never in isolable amounts. © ARKAT-USA, Inc.


Fiserova M.,Pulp and Paper Research Institute | Gigac J.,Pulp and Paper Research Institute
Wood Research | Year: 2015

Beech chips were pre-extracted with hot water and green liquor prior to kraft pulping. The total pulp yield of green liquor pre-extracted chips equivalent to 10% wood weight was approximately the same as that from the original chips, while the pulp yield from hot water pre-extracted chips was lower by 4.2%. Effective alkali charge was reduced by about 3% in kraft pulping of green liquor pre-extracted chips, and by about 1% in kraft pulping of hot water pre-extracted chips when compared with original chips. The pulps from pre-extracted chips demonstrated higher oxygen delignification efficiency and bleachability in the sequence D0(EO)D1D2 as in case of reference pulp from original chips. Consumption of chlorine dioxide in bleaching of pulps from hot water pre-extracted chips was lower by about 17% at 5% wood weight loss and 20.5% at 10% wood weight loss, while in case of pulp from green liquor pre-extracted chips it was lower only by about 5% at the same weight loss compared with the reference pulp. The overall yield of bleached pulps from hot water pre-extracted chips was lower by 1.2 and 3.1%, respectively (at 5 and 10% wood weight loss), of the pulp from green liquor pre-extracted chips by 0.2% in comparison with the reference pulp. Brightness reversion and beatability of bleached pulps from pre-extracted chips was lower as compared with the reference pulp, mainly in case of pulps from hot water pre-extracted chips. Tensile index of bleached pulps prepared from pre-extracted chips was lower, however tear index was higher in comparison with the bleached reference kraft pulp. © 2015, Statny Drevarsky Vyskumny Ustav. All rights reserved.


GlGAC J.,Pulp and Paper Research Institute | Flserova M.,Pulp and Paper Research Institute
Wood Research | Year: 2011

Near infrared spectroscopy offers monitoring of raw materials and paper properties. The data from near infrared spectroskopy (NIR) spectra can by scanned directly on the surface of the handsheets and commercial paper. Data of NIR spectra of semichemical fluting correlate with the filler content, Kappa number as well as directly with strength properties. Concora medium test (CMT), short span compression test (SCT) and burst strength of semichemical fluting may be controlled by semichemical pulp and recovered fibers content in the furnish. Increasing filler content by 1% results in decrease of CMT and SCT by 6.9-7.4%, and burst strength by 12%. Decreasing of strength may be compensated with increased semichemical pulp content in the furnish by around 9.5%.


Russ A.,Pulp and Paper Research Institute | Fiserova M.,Pulp and Paper Research Institute
Wood Research | Year: 2011

PCA analyses of hardwood NIR spectra showed high separation capabilities between ten various hardwood species. A series of measurements in various combinations were made with emphasis on standards and unknown samples drawn from the same lot and at around the same time span. We explain this approach to have a profound effect on the overall selectivity gain. Separation of hardwood species based on their density and classifying them according to the first PCA model led to classification success rate of 96.5%. Separation of all hardwood species into independent components led to lower success rate of 79%. Still, due to switched misidentification on the long run, only the total counts matter, not every single independent identification. Considering this, the selectivity success rises to 85%.


Fiserova M.,Pulp and Paper Research Institute | Gigac J.,Pulp and Paper Research Institute
Cellulose Chemistry and Technology | Year: 2011

Fibre characteristics of kraft pulps from hornbeam, birch, poplar, beech, oak and black locust, namely fibre strength (FS number), fibre length (L number) and bonding ability (B number), were determined by the Pulmac Zero-Span Tester. The fibre strength and fibre length of hardwood kraft pulps increased in the following sequence: black locust pulp < oak pulp < beech pulp < poplar pulp < birch pulp < hornbeam pulp. The influence of laboratory beating on FS number and L number of hardwood kraft pulps is analogous; an increased beating degree reduces slightly these fibre characteristics. On the other hand, the bonding ability of hardwood kraft pulps increased in the sequence: hornbeam pulp < birch pulp < poplar pulp < beech pulp < oak pulp < black locust pulp. With increasing the beating degree, B number increased in the whole range of beating degree, unlike FS number and L number. The tensile index increased in the following sequence: black locust pulp < oak pulp < beech pulp < poplar pulp < birch pulp < hornbeam pulp. The tensile index depends especially on the FS number and L number of hardwood kraft pulps. The lower FS number and L number of beech, oak and black locust kraft pulps are compensated, to some extent, by a higher B number.

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