Pulp and paper
Seyed Mehdi Manzour-olajdad; Omid Ramezani
Abstract
Background and Objectives: Our country has been importing various kinds of wallpaper from different countries for many years. With the increase of foreign exchange problems, the local production of wallpaper and its self-sufficiency has been proposed as a suitable solution. On the other hand, currently, ...
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Background and Objectives: Our country has been importing various kinds of wallpaper from different countries for many years. With the increase of foreign exchange problems, the local production of wallpaper and its self-sufficiency has been proposed as a suitable solution. On the other hand, currently, domestic companies are producing paper from white waste paper, which is not justified for use as printing and writing grades due to many problems. However, many companies in the country are producing white grades from white waste paper, the use of which as a base paper in the production of decorative paper or wall paper has not been scientifically investigated. The purpose of this research is to study and investigate the possibility of producing wall paper from recycled white paper produced in the country.Methodology: The stages of this project were carried out in 6 separate and consecutive phases, which include: 1) determining the quality characteristics of the papers; 2) preparation of coating material formulation with starch as binder; 3) preparation of coating material formulation with latex and starch as binder; 4) coating of papers with the prepared coating formulations ; 5) Coating papers and non-woven fabric (Non-Woven) with polyvinyl chloride (PVC); 6) Application of four-color printing on the selected samples of coated papers. For this purpose, first, samples of papers produced by several Iranian companies were acquired and they were transferred to the laboratory of Biosystems and Bioproducts of Shahid Beheshti University for coating and performing the necessary treatments. In order to perform the mentioned treatment on the paper samples, various chemical substances were used, including calcium carbonate powder, kaolin, titanium oxide, corn starch, latex and PVC powder. With this aim, coating solutions with different percentage of solids were prepared steadily and with trial and error using various combinations of these materials (with a total of 110 and 124 parts). Then, these coated solutions were added on various domestic base papers (mostly recycled). Finally, the image of a flower was printed in four colors on the most desirable coated papers.Results: In determining the quality characteristics of base papers, including measurements of water absorption, ash content, thickness, permeability to air, tensile strength, tear resistance index and burst resistance index, two paper samples produced by two companies of Pardis Paper and Tabriz paper were selected as the best and considering the amount of ash, Tabriz paper was introduced as the base paper more suitable than other local papers. Further, after applying the coating material, coated papers with a relatively favorable appearance and whiteness percentages of about 60 to 85 were obtained, and finally, based on the results, a significant relationship was found between the increase in the solids percentage of the coated solutions and the whiteness percentage of the coated paper. Also, after the printing operation on the selected samples, Rasha Superkraft and Tabriz Kraft papers were introduced as the best samples. Also, the highest quality of printing was reached with PVC on Pars white paper with 16% PVC, on whitetop Rasha with 28% PVC and on non-woven fabric (non-woven fabric) with 28% PVC compared to the weight of the paper.Conclusion: The conclusion of the results of this research are listed below:A) The best solid percentage of coating solution (concentration of the mixture) was 41-46%.b) The best combination of binder and pigment, equal to 100 + 12 + 12 = 124 parts and the ratio of the dry weight of the coating mixture added to the dry weight of the base paper is equal to 12%.c) The highest whiteness obtained by adding calcium carbonate + titanium oxide + starch.t) The most suitable concentration of starch that can be used in the coating solution is 15%.c) The best coating and uniform and good coating appearance was obtained on Rasha Superkraft paper with the formula: kaolin + titanium oxide + latex with a whiteness of 77.7% and on Tabriz kraft paper with the formula: kaolin + titanium oxide + latex, with a whiteness of 71.8%. If higher whiteness is desired, using calcium carbonate instead of kaolin would give a better result.
Pulp and paper
Ali Khalili gasht rodkhani; Ali Ghasemian; Ahmad reza Saraeyan; Mohammad Dahmardeh ghale no; Sayed mehdi Manzorolajdad
Abstract
This study was aimed to investigate the effects of mixing OCC fibers with mixed hardwoods kraft pulp at Iran Wood and Paper Industry Co (Chuka). OCC has been repulped according to the common method in paper recycling industry and its freeness, along with that of virgin kraft pulp, were measured. The ...
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This study was aimed to investigate the effects of mixing OCC fibers with mixed hardwoods kraft pulp at Iran Wood and Paper Industry Co (Chuka). OCC has been repulped according to the common method in paper recycling industry and its freeness, along with that of virgin kraft pulp, were measured. The pulps were beaten to reach the required freeness values to make kraft liner paper, and have been then mixed at 10/90, 20/80, 30/70, 50/50 and 70/30 percentage rates of OCC and virgin kraft pulp, respectively. Handsheets were made from each composition and their mechanical and optical properties have been measured, according to required standard test methods, and compared with those of the control (100% virgin kraft pulp), using ANOVA method. Grouping of the mean values was done by Duncan test and normalization equation was computed to determine the best treatment. The results indicate decreasing the values of tensile, tear and burst, folding endurance and density in comparison with those of the control (100% virgin kraft pulp), but bulk, thickness and opacity have been increased. The score belonging to each treatment show to produce paper possessing proper mechanical and optical properties using OCC fibers, the allowed proportion of these fibers is 50 percent.
Omid Ramazani; Ahmad Jahan latibari; Mohammad mehdi Faezipoor; Ali akbar Enayati; Sayed mehdi Manzor alajdad
Abstract
Apparent Density of paper is the most effective physical property which directly and indirectly affects most of the strength and optical properties of paper such as tensile strength, modulus of elasticity, light scattering coefficient as well as the bonded area between fibers. Since paper making variables ...
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Apparent Density of paper is the most effective physical property which directly and indirectly affects most of the strength and optical properties of paper such as tensile strength, modulus of elasticity, light scattering coefficient as well as the bonded area between fibers. Since paper making variables influences the apparent density of paper, in this study, the influence of OCC pulp freeness, and drying conditions are investigated. The influence of three freeness levels of 350,450, and 550 CSF, drying under strain and unstrained, drying temperatures of 100, 150, 200 C and drying pressure of 7 and 10 kg/cm2 are studied. The relationship between paper making variables and apparent density is developed. All measurements of apparent density were analyzed using Minitab 15 and regression model between independent variables was calculated. The results showed that both pulp freeness and drying temperature had the highest impact on apparent density and both factors increased the apparent density. The response of apparent density of the hand sheets dried at 200 ◦C varied considerably and was analyzed thoroughly. Higher pressure increased apparent density of the sheets. The combined effect of variables is also considered. The combined effect of pulp freeness and drying temperature caused lignin softening and delamination. However, the influence of increasing the drying pressure for unrefined and less refined pulp is not significant. Furthermore, for unstrained drying, the influence of freeness on apparent density was more than strained drying. Manufacturing of more desirable quality papers would be possible considering the obtained results and the effect of Apparent Density on paper strength properties.
