• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.31 no.2
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• pp.42-49
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• 1999

Although many researches have been made on the adsorption of cationic starches onto chemical pulp fibers, only limited studies have been reported for deinked pulp(DIP) and thermomechanical pulpI(TMP). In this experiment, the adsorption behavior of the cationic starches onto DIP and TMP fibers investigated. Almost complete adsorption of cationic starches onto the pulp fibers were observed when the addition rate of starch was low. Adsorption ratio decreased abruptly when 3.5% and 4.0% of cationic starches were adsorbed onto deinked pulp and thermomechanical pulp, respectively. Adsorption of cationic starches increased as the degree of substitution decreased and as the pH of the pulp slurry increased. TMP fibers adsorbed more cationic starches than DIP because of its greater charge density, and this led to greater improvement in strength properties for the TMP sheets.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 1999.11b
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• pp.84-89
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• 1999

Treatment with the enzyme pectinase has been reported to lower the cationic demand of thermomechanical pulp(TMP) bleached with alkaline peroxide in the laboratory. We have extended this discovery to bleached TMP produced industrially, and shown that commercial enzyme preparations can treat pulp within 15 minutes at the at the temperature and pH values prevalent in paper mills. About half of the cationic demand in the bleached pulp can be destroyed by pectinase. Dynamic drainage jar experiments show that the enzyme treatment improves the effectiveness of several cationic polymers to increase retention in the absence of retention aids or with non-ionic polymers, and does not damage the strength properties of the pulp. Pectinase could be easily incorporated into paper machine stock preparation systems to lower the charges of cationic retention aids needed in furnishes containing peroxide-bleached mechanical pulp.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2006.06a
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• pp.51-59
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• 2006

The surface of various mechanical pulp fibres including thermomechanical pulp (TMP), chemithermomechanical pulp (CTMP), and alkaline peroxide mechanical pulp (APMP) fibres, were characterized using SEM, AFM, and XPS. With SEM and AFM, middle lamella material was observed to be non-fibrillar, patch-like, while fibre secondary wall was observed to have a microfibrillar structure. It was found that after the first-stage refiner, lignin-rich middle lamella remainders are present on the fibre surface of all three pulps, although most of the fibre surfaces expose microfibrillar structure. After the final-stage refining, large amounts of granules are present on the TMP fibre surface. In contrast, most middle lamella remainders remain on the surface of CTMP fibres after final stage refining and even after peroxide bleaching. XPS results have confirmed that the non-fibrillar surface material is the lignin-rich middle lamella remainder., and the remainders of middle lamella contribute to the high surface lignin concentration.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.47 no.1
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• pp.35-44
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• 2015

Thermomechanical pulping process uses large amounts of energy, mostly electricity to run electrical facilities. Thermomechanical pulp (TMP) made from Pinus densiflora also has a big drawback that refining consumes 90 per cent of the total energy used in TMP process. This study explored to draw up a way to save refining energy through different thermal treatment at the stages of presteaming and refining. Presteaming temperature was $80^{\circ}C$, $100^{\circ}C$, and $120^{\circ}C$. After presteaming at each temperature, refining was carried out at $100^{\circ}C$, $120^{\circ}C$, and $140^{\circ}C$ respectively. In a presteaming stage, steaming temperature over $120^{\circ}C$ greatly contributed to the decrease of refining energy leading to earlier attainment of a target freeness, irrespective of refining temperature. In addition, NaOH treatment with presteaming enhanced better development of fiber properties during refining than presteaming without NaOH. High temperature refining at $140^{\circ}C$ produced a high strength paper, and wood chips treated by alkali responded better to refining than at over $120^{\circ}C$. Improved softening effect on wood chips led to the decrease in shives contents but it gave no effect on pitch contents of TMP.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.47 no.5
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• pp.33-42
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• 2015

Pitches contained in thermomechanical pulp negatively influence paper qaulity and pulp and papermaking process. Without controlling TMP pitches suitably, it is hard to make a certain quality of paper. In order to control pitches in TMP, they must be quantitatively recognized by proper tools. One of the most widely used way to detecting TMP pitches is a staining method using a hydrophobic dye such as Sudan IV. Sudan IV could be used with three different protocols including different application of its dissolution, washing, dyeing time, etc. The dyeing protocols were classified into three categories including Stain I, Stain II, and Stain III. In dyeing time, Stain I required more than 24 hours to dye pitches. On the other hand, Stain III could stain TMP pitches with the most brief way. The images of red-stained pitches could be captured by a stereomicroscope with ${\times}35$ and ${\times}45$ magnifications, and then quantitatively analysed measuring their numbers and areas by Carl Zeiss AxioVision (ver. 4.8.2) program. Among three protocols, both Stain I and Stain III were the most ideal methods to detect TMP pitches because they detected more pitches and bigger pitch areas compared to Stain II against the same specimen. In particular, it was recognized that Stain III could be used as the most useful tool to detect TMP pitches accurately within several minutes.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.46 no.3
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• pp.20-27
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• 2014

Nowadays, the bleaching techniques of thermomechanical pulp(TMP) are fast developing on the strength of some benefits, mainly on low production cost and good fiber property. In this study, the optimum concentration of bleaching chemicals and the environmental load of bleaching wastes were considered to improve the bleaching efficiency of thermomechanical pulp using Korean redpine(Pinus densiflora) under the peroxide-based bleaching system. The optical property of TMP after bleaching was planned to use higher grade of paper, like printing & writting paper, not general newspaper. The concentration of bleaching chemicals, NaOH, $Na_2SiO_3$ and EDTA, in hydrogen peroxide bleaching system, on the basis of O.D. pulp was closely influenced on the improvement of TMP brightness. Final target of bleaching efficiency was set up to above 76%-ISO brightness. The optimal target brightness of Korean redpine TMP was reached to 76.45%-ISO under the conditions of $H_2O_2$ 7% with NaOH 2.20%, $Na_2SiO_3$ 0.63% and EDTA 0.02%. The concentration of NaOH, $Na_2SiO_3$ and EDTA was correlated functional to the residual peroxide content of wastewater, pH value and electric conductivity of TMP fibers after bleaching treatment. The optimal bleaching conditions by controlling the addition amount of chemicals were positively contributed to the brightness stabilization and environmental load of TMP.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.39 no.4
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• pp.45-52
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• 2007

Whole, bast and core fibers of kenaf cultivar Tainung-2 were pulped under different pulping methods, thermomechanical and kraft pulping methods. The physical and optical properties of kenaf TMP(thermomechanical pulp) and KP(kraft pulp) handsheets were investigated and the results from the study are summarized as follows: Yields of TMP and KP were $77{\sim}87%\;and\;43{\sim}52%$, respectively. There was no significant change in apparent density between kenaf KP and USKP(unbleached softwood kraft pulp) but TMP showed a little lower apparent density. Bast pulp had the lowest apparent density regardless of pulping methods. Tensile strength of kenaf KP was higher than that of TMP but similar to that of USKP. Both TMP and KP handsheets of bast fraction showed the highest tear strengths among whole, bast, and core fractions. Core fraction showed the lowest tear strengths under different pulping methods. In general burst strength of kenaf pulp under different pulping methods was lower than that of USKP, and kenaf pulp had better stiffness than USKP. Brightness of kenaf KP and TMP was higher than that of USKP. There was no significant variation in opacity between kenaf pulp and USKP even though kenaf pulp showed a little lower opacity. The main difference in paper quality between the core fiber and bast fiber is derived from the fact that bast fiber is long and thin, whereas core fiber is short and thick.

• Journal of the Korean Wood Science and Technology
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• v.44 no.1
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• pp.135-146
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• 2016

Three fiber sources including Russian spruce (Picea jezoensis) and larix (Larix leptolepis), and Myanmar bamboo (Phyllostachys bambusoides) for thermomechanical pulp were explored to replace domestic pine (Pinus densiflora) pulp that has some limitations in an aspect of supply and pitch trouble. Thermomechanical pulps were manufactured under the identical condition, and then compared with their representative pulp properties and pulping process. Both Russian larix and Myanmar bamboo contained large amounts of extractives that would negatively affect mechanical pulping processes. Russian spruce showed the least contents in shives and pitch. Russian spruce and domestic pine reached an optimum freeness level within a short pulp processing time, which consumed less amount of refining energy compared to larix and bamboo. In particular, the spruce wood showed the highest brightness level which might lead to a less consumption of bleaching chemicals. It was expected that Russian spruce could be replaced with the domestic pine wood in respect of both pulping process and pulp quality.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.48 no.2
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• pp.28-33
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• 2016

This study was conducted to investigate the effects of deep eutectic solvent (DES) treatment on properties of TMP fibers and handsheets. DES was prepared by mixing of lactic acid and betaine (L and B), and the molar ratio of these two components mixtures was controlled to 2:1 (L:B=2:1) and 5:1 (L:B=5:1). As results, lignin was partly extracted from the TMP fibers. Especially, the delignification of TMP samples was promoted according to the increase of the molar ratio of lactic acid. Except for tear index, both tensile index and burst index of handsheets were increased when higher molar ratio of lactic acid was mixed for DES preparation. However, the LB DES treatment of TMP fibers didn't give any effect on the optical properties of TMP handsheets. The plausibility of TMP fiber was to be enhanced by LB DES treatment.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.47 no.5
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• pp.5-14
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• 2015

Recently, the use of wood resources has been limited due to global environmental change, like global warming and desertification. It is very critical in Korea's paper industries because lots of virgin pulp are dependant on direct import from abroad for printing grade of paper. In this work, the alternatively best available technique for reducing the import amounts of BKP (bleached Kraft pulp) was considered by mixing DIP (deinked pulp) and TMP (thermomechanical pulp) for the manufacture of high quality paper. Generally known, the sheet prepared from fibrous raw materials of DIP and TMP has lower strength and optical properties than that prepared from BKP. This study was aimed to improve the sheet quality by using DIP and TMP. 4 kinds of polyelectrolytes were approached to find out the best effects on physical strength and optical brightness improvements, and high retention behaviors with GCC (ground calcium carbonate). In conclusion, amphoteric PAM with 1,000,000 molecular weight (g/mol) and 0.5 charge density (meq/g) was best for the improvement of strength properties with the mixture of DIP and TMP. GCC retention rate was also the highest with cationic-PAM of above 2,000,000 molecular weight (g/mol) and about 2.0-3.0 charge density (meq/g) of strengthening agent.