Discussion on Process Technology of Paper Pulp Paper Made from Masson Pine Chemical Pulp

Papermaking with masson pine is the most common method in the country. In the production process, how to select good raw materials and grasp technological factors is the key to producing high quality paper bags. We know that scientific technology and good raw materials are prerequisites for the production of qualified products. And strict and scientific enterprise management is the key to improving production and stabilizing quality.
First, strict control of cooking process:
The correct cooking process conditions are important ways to maintain fiber strength and improve the quality of paper bags. First, we conducted cooking experiments under different process conditions in laboratory and medium-scale production experiments; then, we identified the best process for pulping in our plant. The following table is the medium-sized production experimental data of the same cooking steaming curve in our factory. No. Alkali use (% by Na2O) Liquid Specific Hardness Kappa Number Gradient (OSR) Quantitative (g/m2) Longitudinal Energy (j/m2) Tear (mN) Thick Paste (%) 1 14 1 :2.3 70.5 28 80 53 880 2.3 2 14.8 1:2.6 66 28 80 58 1200 1.8 3 14.9 1:2.8 63 28 80 56 1000 1.5 4 15.6 1:3.0 62 28 80 54 890 1.3
From the above table, it can be seen that the paper strength in a certain range is increased with the increase of the cooking liquor ratio, and the coarse pulp amount decreases with the increase of the alkali amount. However, if the liquefaction is greater than 1:30 and the amount of alkali used is greater than 15.6%, the effect is not significant, and steam and alkali are consumed, which is not conducive to improving economic efficiency. Therefore, proper liquefaction and alkali content should be taken during cooking, and mild cooking conditions of long-penetration and short-term heat preservation should be used to ensure the strength of the paper bag.
The following is the production process of our factory after many small experiments and large-scale production practices. Alkali content for project (% as Na2O,%) Vulcanization degree (calculated as Na2O, %) Ratio of liquid to primary heating (h) Small bleed air (h) Medium heat (h) Secondary temperature rise (h) High thermal insulation (h) Hardness Kappa number parameter 14.8 25 1:2.6 1:30 1:10 1:00 1:00 1:00 60-65
From the process we have developed above, we can see that we fully consider the effect of vulcanization on the cooking process:
1. Sulfur content should be appropriate to protect the fiber and promote the role of delignification;
2. The degree of vulcanization should not be too high, so as not to pollute the air, deepen the color, and cause a certain burden on the recovery of the alkali.
Second, the strict control of the pulping process:
Choosing the right beating process is the key to increase fiber binding and improve the physical properties of the paper. The effect of the pulping process on several important physical properties of the paper sheet is discussed below:
a. Beating concentration and energy relationship:
Paper-bag paper is sulphate beating, the domestic small and medium-sized paper mills mainly use double-disc grinding, the concentration is generally between 3.0% and 3.9%, we found that when the low-strength beating, the fiber is easily severed; the concentration is high At the time, the thicker layer between the flight knife and bedknife is conducive to the promotion of fiber squeezing and kneading, which contributes to the defiberization and degeneration of the fibers, the swelling of the pulp fibers, and the richness of the fibers. Good power. The following table shows the effect of beating concentration on pulp formation rate, paper formation energy, and tearing degree in the actual production process. Project degradation degree (OSR) Deuteration rate (%) Longitudinal energy (J/m2) Tear (mN) Remarks Depth 3.0% 26 6.5 52 880 Double disc mill with three φ450 series units Knife 3.2% 26 7 54.5 890 3.51% 26 8 56 1100 3.98 26 14 58 1270 It can be seen from the above table that when the beating concentration is high, the energy is also high. The high energy of paper bag paper is reflected in the net effect of paper bag paper. The so-called net effect is the product of the tension and elongation in the vertical and horizontal directions. High-energy paper-bag paper, which usually has a low bag-breaking rate, is a very important physical performance index for measuring paper bags from a dynamic point of view.
b. Beating process and tearing relationship:
Paper bag paper to ensure that tear can meet the quality requirements, with the double disc grinding. Should first fall light knife, so that the fiber wall is first worn, water molecules can enter the fiber, increase the fiber's water retention value, the fiber becomes soft, so that then drop heavy knife, fiber capacity increased, and was cut off to reduce the extent. Therefore, the fiber is maintained at a certain length, thereby increasing the degree of paper tear. The papermaking experts of the Soviet Union studied paper-making bag paper and called the fiber fraction less than 0.5 mm in length as the proportion of small fibers. Tests have found that increasing the proportion of small fibers in the pulp increases the burst strength, tensile strength, and elongation of the paper bag, while the tearing rate decreases. Increasing the proportion of medium fibers increases the bursting, pulling, and elongation of the paper bags, while the tearing degree decreases. With an increase in the medium fiber content, the burst strength, the tensile force and the elongation are reduced, and the tearing degree is increased. If the long fiber content is increased, various strengths of the paper bag paper can be improved.
c. Paper bag paper permeability and degree of relief:
The air permeability of paper bags decreases as the degree of freeness increases. The decrease in air permeability is due to the fact that the fiber with a high degree of beating is larger than the surface, and this type of fiber copy paper is generally tightly bonded, so that the micropores of the paper are greatly reduced. As a result, the absorbency is decreased, and the air permeability is also decreased.
Third, paper bag paper sizing process control:
During the sizing process of paper bag paper, sizing process control is crucial to the sizing effect. We use YA-301 fully dispersible dispersible rosin gum produced by Jiangxi Ruichang. This paste must be added to the pulp tank after 15 minutes of circulation to add alum, and then fully cycled for 15 minutes before paper machine copying. When adding water, you must adjust the PH value. At higher temperatures, the pH of whitewater under the net is controlled between 5.2 and 5.6. When the temperature is low, the pH of the white water under the net is controlled to be between 5.5 and 6.0. It is not possible to leave the excess alum in the paper sheet, making the paper sheet brittle and affecting the vertical and horizontal energy of the paper.
Fourth, the process control of paper in paper machine copying process:
a. Headbox operation:
The headbox is one of the key components of the paper machine. It determines the formation of the web and the distribution uniformity and stability of the paper web, and has a great influence on the physical strength properties of the paper. A uniform, stable paper web can be produced, the most critical being the pressure to operate the headbox. Paper bag paper requires good air permeability and strong toughness, which requires pulp speed ratio greater than 1. We usually require a pulp to mesh ratio of 1.005 to 1:1.01 to 1.
b. Paper speed difference and paper sheet performance.
In the process of papermaking, the paper machine should minimize the speed difference between the web to the press section, between the press and the press, and between the press and the bake under the condition that the paper cannot be shrunk to make a fold, allowing the paper to have longitudinal and transverse directions. Be sure to shrink so as to minimize the traction caused by the shrinking of the sheet and increase the elongation of the sheet.
From the above discussion, it can be seen that paper bag paper production from stock preparation to pulping, from pulping to paper machine copying is a systematic project, and the qualification rate of wood chips should be emphasized when preparing materials. The paper machine is a huge group of linked motives. All parts must be strictly controlled from the process to the operation of the equipment. Accurate operation is required to produce high strength paper bags. After several years of exploration, we have completely produced paper that meets the requirements for the quality of Class B paper bags. (Zhan Jinchun, Fujian Shaoshan Paper Group)