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.
Behrouz Neyciyani; Majid Azizi; Behnam Gholampoor; Hadi Gholamiyan; Nemat Mohebi
Abstract
One of the most important economic goals of any state or economic system is to maintain a competitive position in every market. Competition in the market is ultimately improving the well - being of consumers and economic performance. Market analysis in order to resolve appropriate decisions by relevant ...
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One of the most important economic goals of any state or economic system is to maintain a competitive position in every market. Competition in the market is ultimately improving the well - being of consumers and economic performance. Market analysis in order to resolve appropriate decisions by relevant agencies requires recognition of its structure. In order to judge the extent of competition and monopoly on each market, the concept of Concentration is primarily used. Different indicators are used to measure the market concentration. This study was conducted with the aim of assessing the market concentration of Iran bedroom furniture and showing changes for the period from 1388 to 1397. In this regard, indicators of market concentration such as Concentration ratio, Herfindahl-Hirschman, Hall-Tiedman, Comprehensive concentration index and Hana-Kay were calculated. According to the results of the Herfindahl-Hirschman index, the furniture import market in this period is uncompetitive and the kind of monopoly of the firm and in 1396 year the market structure of a multi - lateral monopoly. According to the Hall-Tiedman Index, the market structure was a multi - faceted monopoly. Comprehensive index values of industrial concentration show a multi - sided monopoly market. The increase in the values of the Hana-Kay index has reached from 1388 to 1397, indicating a decline in the monopoly of the market. In general, in this regard, indicators of market concentration such as, Concentration ratio, Herfindahl-Hirschman, Hall-Tiedman, Comprehensive concentration index and Hana-Kay were calculated. The results show the existence of an oligopoly on the market. Monopoly has fluctuated with regards to the countries political-economic conditions in the mentioned period.
