Pulp and paper
Saeed Mahdavi; Behnam Gholampoor
Abstract
Background and objectives: In addition to reducing the consumption of various resources such as water, energy, and wood, paper recycling is constantly increasing in different countries due to less pollution. One of the major defects of the old corrugated container (OCC) is its relatively weak strength, ...
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Background and objectives: In addition to reducing the consumption of various resources such as water, energy, and wood, paper recycling is constantly increasing in different countries due to less pollution. One of the major defects of the old corrugated container (OCC) is its relatively weak strength, which has limited its use in various sections of the packaging industry. In this study, the effect of using some additives was studied to improve the strengths of OCC to make the top liner of cartons in both wet and dry conditions.Methodology: OCC was prepared from domestically produced cartons. To determine the performance and optimal amount of additives, corn cationic starch (at 1, 1.4 and, 2%), wet strength resin (at 1, 2 and, 3%), AKD (at 1, 2 and, 3%), and imported tea envelope recycled long fiber paper (at 10, 15 and, 20%) were separately used as additives based on the dry weight of OCC pulp. The handsheets made by laboratory sheet former with a basis weight of 120 g/m2 and then tensile, burst, and tear indices were measured at wet and dry conditions to compare the effect of additives. Also, water absorption was measured by the Cobb test on the test samples. The optimal level of each additive was determined based on the results, then handsheets made from optimal combination treatment including appropriate levels of all additives, and different properties of handsheets were statistically compared.Results: The water absorption of handsheet was decreased by 90% compared to the control by adding AKD. This additive was able to decline the water absorption of handsheet made from OCC to about 20 g/m2 as the suitable range. The greatest increase of wet tensile strength of the handsheet was achieved using 3% wet strength resin compared to the control. The resin maintained the wet tensile, burst, and tear indices of the residual strength of handsheet by 25, 46, and 58%, respectively, compared to dry strengths so it has good performance. The results showed that by adding cationic corn starch and recycled long fiber paper, all the dry strengths of handsheet independently increased compared to the control. The optimal combination treatment was determined according to the independent use of additives in OCC pulp, including 1% cationic starch, 1% AKD, and 3% wet strength resin based on technical-economic considerations. There is no significant difference between dry tensile and burst strength of handsheet using this treatment and 20% recycled long fiber paper, which both means ranked statistically in the same group. Conclusion: The use of 20% recycled long fiber paper of tea wrapper has significantly improved the dry strength of OCC pulp, but adding 1% cationic corn starch to OCC pulp caused a few increases of dry strength. The wet strength of handsheet was significantly improved by adding 3% wet strength resin whereas 1% AKD significantly decreased the water absorption of the OCC pulp to 14 g/m2. The optimal combination treatment of chemical additives including 1% cationic corn starch, 1% AKD, and 3% wet strength resin improved the wet and dry strength of handsheet made from OCC pulp that could be used for packaging products that should be kept in refrigerator and freezer.
Saeed Mahdavi; Mohammad Hadi Rezvani
Abstract
Kenaf as an industrial plant can play an important role in providing shortage of virgin fiber for paper and board based on the history of cultivation in Iran. Harvesting time of kenaf is one of the most important economic-technical aspect, so the growth rate of kenaf (variety of Cuba) and the weight ...
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Kenaf as an industrial plant can play an important role in providing shortage of virgin fiber for paper and board based on the history of cultivation in Iran. Harvesting time of kenaf is one of the most important economic-technical aspect, so the growth rate of kenaf (variety of Cuba) and the weight ratio of bast, core and pith individually were measured at 5, 6 and 7 months after planting and kenaf biomass was determined after 7 month. Soda-AQ pulping from kenaf bast fiber was adjusted at 14% and 16% chemical charges, 175°C, 120 min., liquor to bast fiber of 5:1 and adding 0.2% AQ. Handsheet was made by the bast pulp from the three harvested times with base weight of 110 g/m2. The results showed that by increasing the harvest period from 5 to 6 and 7 months, stalk height and diameter increased 9% and 5%, and vice versa, respectively. The weight ratio of kenaf bast to core has decreased by increasing of harvest time. Dry and green biomass of kenaf was determined at 33.1 and 7.7 t/ha, respectively. Screen yield, kappa number, and reject were of pulp were measured for combinations of optimal cooking in range of 48.8% to 52.9%, 35.4 to 72.6, and 0.92% to 2.5%, respectively. The beating energy consumption of pulp that prepared from 7 month harvesting time was greater than the others. Optimal conditions were determined as harvesting time of 5 month and cooking variables of 120 min, 165 °C and 16% NaOH for carton top liner. Handmade paper properties compared to kraft liner paper confirms the superiority of paper made from virgin kenaf bast fiber according to national standard of Iran (ISIRI 3054).
