A method for manufacturing a hand account paper

Abstract

The present application belongs to the field of papermaking, and particularly relates to a manufacturing method of hand notebook paper, comprising the following steps: wood pulp is prepared for papermaking, then concentrated pulp screening, material adjusting, pulp beating, sand and gas removing, sizing, paper machine screening, net section dehydration molding, pressing, pre-drying, surface sizing, post-drying, calendering, and obtaining the hand notebook paper. The present application optimizes the conditions of key papermaking processes such as papermaking preparation, pulp beating and surface sizing, and obtains high-quality hand notebook paper. The hand notebook paper manufactured by the method has super-high opacity, uniform thickness, good evenness, high smoothness and long-term storage resistance.

Description

Technical Field

[0001] This invention belongs to the field of papermaking, and in particular relates to a method for manufacturing journal paper. Background Technology

[0002] Journaling paper is a type of paper used in small notebooks that are carried around frequently to record thoughts, tasks, and things to avoid forgetting. It requires extremely high opacity, uniform thickness, good evenness, high smoothness, and long-term preservation. The consumer group for journaling products is relatively young, with university students and young working professionals making up a large proportion. Developing journaling paper is of great significance for filling a domestic market gap and increasing product profit margins. Summary of the Invention

[0003] In view of this, the object of the present invention is to provide a method for manufacturing journal paper, which can be used to manufacture high-quality journal paper.

[0004] This invention provides a method for manufacturing journal paper, comprising the following steps:

[0005] Wood pulp is mixed and then screened, seasoned, rinsed, desanded and deaerated, coated, screened on the paper machine, dewatered and formed on the wire section, pressed, pre-dried, surface sizing, post-dried, and calendered to obtain journal paper.

[0006] The specific process of preparing the pulp includes: adding polyacrylamide to bleached sulfate softwood chemical pulp and beating it to obtain bleached sulfate softwood chemical pulp with a freeness of 46-48°SR; adding polyacrylamide to bleached sulfate hardwood chemical pulp and beating it to obtain bleached sulfate hardwood chemical pulp with a freeness of 38-40°SR; mixing the bleached sulfate softwood chemical pulp with a freeness of 46-48°SR, the bleached sulfate hardwood chemical pulp with a freeness of 38-40°SR, and alkaline hydrogen peroxide bleached poplar mechanical pulp with a freeness of 50-52°SR at a mass ratio of (3-5):(4-6):1, adjusting the concentration to obtain concentrated paper pulp;

[0007] During the pulping process, fillers are added to the pulp. The fillers are calcium silicate and calcined kaolin, and the mass ratio of calcium silicate to calcined kaolin is 1:(0.5-2). The content of the fillers in the journal paper is 25-30 wt%.

[0008] The surface sizing process specifically includes: sequentially applying a surface sizing agent and a coating to the paper surface; wherein, by weight, the coating comprises 100 parts titanium dioxide, 5-10 parts polyvinyl alcohol, 20-30 parts starch, 0.2-0.6 parts lubricant, and 0.3-0.6 parts water-resistant agent, and the coating amount is 3-5 g / m². 2 .

[0009] Preferably, the amount of polyacrylamide added to bleached sulfate softwood chemical pulp is 0.3-0.6 kg / ton of pulp; the amount of polyacrylamide added to bleached sulfate hardwood chemical pulp is 0.3-0.6 kg / ton of pulp.

[0010] Preferably, the bleached sulfate softwood chemical pulp with a freeness of 46-48°SR, the bleached sulfate hardwood chemical pulp with a freeness of 38-40°SR, and the alkaline hydrogen peroxide bleached poplar mechanical pulp with a freeness of 50-52°SR are mixed at a mass ratio of 4:5:1.

[0011] Preferably, the concentration of the paper pulp is 3.1 to 3.9 wt%.

[0012] Preferably, the mass ratio of calcium silicate to calcined kaolin is 1:1.

[0013] Preferably, during the slurry preparation process, auxiliary materials are added to the slurry, including sizing agents, retention aids, cationic starch, and wet strength agents.

[0014] Preferably, the amount of the internal sizing agent added is 28-32 kg / ton of paper; the amount of the retention aid added is 0.3-0.6 kg / ton of paper; the amount of the cationic starch added is 6-8 kg / ton of paper; and the amount of the wet strength agent added is 20-26 kg / ton of paper.

[0015] Preferably, the surface sizing agent is a starch adhesive solution with a concentration of 10-20 wt%; the dry coating weight of the surface sizing agent is 1-2 g / m². 2 .

[0016] Preferably, the starch adhesive also contains a lubricant.

[0017] Preferably, the smoothness of the journal paper is 50-70s.

[0018] Compared with the prior art, the present invention provides a method for manufacturing journal paper, comprising the following steps: wood pulp is prepared, then screened as thick pulp, seasoned, rinsed, desanded and deaerated, loaded with sizing, screened on a paper machine, dewatered and formed on the wire section, pressed, pre-dried, surface sizing, post-dried, and calendered to obtain journal paper; the preparation process specifically includes: adding polyacrylamide to bleached sulfate softwood chemical pulp and beating it to obtain bleached sulfate softwood chemical pulp with a freeness of 46-48°SR; adding polyacrylamide to bleached sulfate hardwood chemical pulp and beating it to obtain bleached sulfate hardwood chemical pulp with a freeness of 38-40°SR; and combining the bleached sulfate softwood chemical pulp with a freeness of 46-48°SR and the bleached sulfate hardwood chemical pulp with a freeness of 38-40°SR. Pulp from leafy wood is mixed with alkaline hydrogen peroxide bleached poplar mechanical pulp with a freeness of 50-52°SR at a mass ratio of (3-5):(4-6):1, and the concentration is adjusted to obtain concentrated pulp for papermaking. During the pulping process, fillers are added to the pulp. The fillers are calcium silicate and calcined kaolin, with a mass ratio of calcium silicate to calcined kaolin of 1:(0.5-2). The filler content in the paper is 25-30 wt%. The surface sizing process specifically includes sequentially coating the paper surface with a surface sizing agent and a coating. The coating, by mass parts, comprises 100 parts titanium dioxide, 5-10 parts polyvinyl alcohol, 20-30 parts starch, 0.2-0.6 parts lubricant, and 0.3-0.6 parts water-resistant agent. The coating amount is 3-5 g / m³. 2 The journal paper produced by the method of this invention has extremely high opacity, uniform thickness, good uniformity, high smoothness, and is durable for long-term preservation. Detailed Implementation

[0019] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] This invention provides a method for manufacturing journal paper, comprising the following steps:

[0021] Wood pulp is mixed and then screened, seasoned, rinsed, desanded and deaerated, coated, screened on a paper machine, dewatered and formed on the wire section, pressed, pre-dried, surface sizing, post-dried, and calendered to obtain journal paper.

[0022] In the method provided by this invention, the copying process specifically includes:

[0023] Polyacrylamide is added to bleached sulfate softwood chemical pulp, and the pulp is beaten to obtain beaten bleached sulfate softwood chemical pulp. The preferred amount of polyacrylamide added to the bleached sulfate softwood chemical pulp is 0.3–0.6 kg / ton of pulp, specifically 0.3 kg / ton, 0.35 kg / ton, 0.4 kg / ton, 0.45 kg / ton, 0.5 kg / ton, 0.55 kg / ton, or 0.6 kg / ton. The freeness of the treated bleached sulfate softwood chemical pulp is 46–48°SR, specifically 46°SR, 46.5°SR, 47°SR, 47.5°SR, or 48°SR.

[0024] Polyacrylamide is added to bleached sulfate hardwood chemical pulp, and the pulp is beaten to obtain beaten bleached sulfate hardwood chemical pulp. The preferred amount of polyacrylamide added to the bleached sulfate hardwood chemical pulp is 0.3–0.6 kg / ton of pulp, specifically 0.3 kg / ton, 0.35 kg / ton of pulp, 0.4 kg / ton of pulp, 0.45 kg / ton of pulp, 0.5 kg / ton of pulp, 0.55 kg / ton of pulp, or 0.6 kg / ton of pulp. The freeness of the treated bleached sulfate hardwood chemical pulp is 38–40°SR, specifically 38°SR, 38.5°SR, 39°SR, 39.5°SR, or 40°SR.

[0025] The bleached sulfate softwood chemical pulp and the bleached sulfate hardwood chemical pulp after beating are mixed with alkaline hydrogen peroxide bleached poplar mechanical pulp, and the concentration is adjusted to obtain a concentrated paper pulp. The alkaline hydrogen peroxide bleached poplar mechanical pulp is not beating and has a freeness of 50–52°SR, specifically 50°SR, 50.5°SR, 51°SR, 51.5°SR, or 52°SR. The bleached sulfate softwood chemical pulp after beating is mixed with alkaline hydrogen peroxide bleached poplar mechanical pulp. The mass ratio of wood chemical pulp, bleached sulfate hardwood chemical pulp after pulping treatment, and alkaline hydrogen peroxide bleached poplar mechanical pulp is (3-5):(4-6):1, preferably 4:5:1; the concentration of the papermaking pulp obtained after concentration adjustment is preferably 3.1-3.9 wt%, specifically 3.1 wt%, 3.2 wt%, 3.3 wt%, 3.4 wt%, 3.5 wt%, 3.6 wt%, 3.7 wt%, 3.8 wt%, or 3.9 wt%.

[0026] In the method provided by this invention, the purpose of the thick pulp screening is to separate harmful impurities from the pulp with minimal fiber loss. In a specific embodiment of this invention, the thick pulp screening is preferably divided into three sections, with the screening machine arranged between the mixing tank and the pulp tank of the paper machine, as detailed below:

[0027] (1) The model of the primary slurry screening machine is MODUScreen C&F50w, equipped with a 315kw motor. The aperture of the coarse screen section is 6.0mm, and the screening area is 1.6m². 2 The fine sieve section has a 0.15mm gap in its rotating drum, resulting in a sieve area of ​​3.25m². 2 The MODUScreen C&F50w is an outflow screen that combines the functions of coarse and fine screening. The screen has two distinct sections: a perforated upper cylinder for coarse screening and a slit lower cylinder for fine screening. The slurry is added to the bottom of the coarse screening section and enters the equipment. The slurry then moves upwards, being screened by the perforated cylinder. The good slurry flows into the fine screening section. Two types of slurry are discharged from the coarse screening section: light impurities are removed from the top, and heavy impurities are collected in a debris collector. The good slurry from the coarse screening section enters the fine screening section, where it is screened by the slit cylinder and moves downwards. Both the good slurry and the slurry from the fine screening section are discharged from the bottom of the screen.

[0028] (2) The two-stage thick slurry screen is model MODUScreen F20, equipped with a 55kw motor. The screen cylinder has a 0.15mm gap, and the screening area is 0.64m². 2 The MODUScreen F20 is an outflow screen used for screening and separation. The MODUScreen F20 has a fixed screen frame and rotor. The rotor is typically enclosed, but a blade-type rotor can also be used in some applications. The slurry is fed from the top of the screen, and after entering the screen, the slurry begins to move downwards while being screened. Good slurry and sludge flow out from the bottom of the screen.

[0029] (3) The three-stage thick slurry screen is model MODUScreen F10, equipped with a 37kw motor, with a 0.15mm gap in the screen drum and a screen drum area of ​​0.30m². 2 The MODUScreen F10 is an outflow screen used for screening and separation, functioning the same as the second-stage thickener screen.

[0030] In the method provided by this invention, the seasoning refers to all the materials mixed together and added to the mixing tank.

[0031] In the method provided by the present invention, the slurry flushing refers to using a slurry flushing pump to pressurize and achieve thorough mixing of the slurry. During the pulping process, fillers are added to the pulp, namely calcium silicate and calcined kaolin; the mass ratio of calcium silicate to calcined kaolin is 1:(0.5-2), preferably 1:0.5, 1:0.6, 1:0.7, 1:0.8, 1:0.9, 1:1, 1:1.1, 1:1.2, 1:1.3, 1:1.4, 1:1.5, 1:1.6, 1:1.7, 1:1.8, 1:1.9 or 1:2; the final content of the filler in the journal paper is controlled at 25-30 wt%, specifically 25 wt%, 25.5 wt%, 26 wt%, 26.5 wt%, 27 wt%, 27.5 wt%, 28 wt%, 28.5 wt%, 29 wt%, 29.5 wt% or 30 wt%. In this invention, during the pulping process, it is preferable to add auxiliary materials to the pulp, including an internal sizing agent, a retention aid, cationic starch, and a wet strength agent; wherein, the amount of the internal sizing agent added is preferably 28-32 kg / ton of paper, specifically 28 kg / ton of paper, 29 kg / ton of paper, 30 kg / ton of paper, 31 kg / ton of paper, or 32 kg / ton of paper; the amount of the retention aid added is preferably 0.3-0.6 kg / ton of paper, specifically 0.3 kg / ton of paper or 0.4 kg / ton of paper. The amount of cationic starch added is preferably 6-8 kg / ton of paper, specifically 6 kg / ton, 6.5 kg / ton, 7 kg / ton, 7.5 kg / ton, or 8 kg / ton of paper; the amount of wet strength agent added is preferably 20-26 kg / ton of paper, specifically 20 kg / ton, 21 kg / ton, 22 kg / ton, 23 kg / ton, 24 kg / ton, 25 kg / ton, or 26 kg / ton of paper. In this invention, the concentration of the thin pulp obtained after dilution is preferably 0.9-1 wt%.

[0032] In the method provided by this invention, the desanding and degassing are for removing slurry residue and gas from the slurry. In a specific embodiment of this invention, the desanding is carried out in a slag remover, and the degassing is carried out in a degassing tank, as detailed below:

[0033] (1) The slurry desander is an AhlCleaner SC133. The SC133 slurry desander is pressurized, and the slurry flows radially within the desander cone, while the axial slurry orifice is sealed with a sight glass. The slurry in the pressurized slurry desander is based on the pressure difference between the good slurry and the slurry. In the SC133 slurry desander, a vortex-controlled nozzle is inserted into the axial slurry orifice.

[0034] (2) The purpose of the degassing section is to remove entrained air and dissolved gases from the slurry. The degassing tank is of the following model: The Deculator MRD1900×10400Dual is used for degassing headbox slurry and headbox dilution water. Degassing is performed under vacuum conditions while the slurry is boiling. The vacuum is typically generated by two vacuum pumps connected in series. When the slurry and white water are sprayed onto the top of the degassing tank, air and other gases are effectively removed from the slurry and white water. The air is then discharged from the degassing tank by the vacuum pump.

[0035] In the method provided by this invention, in a specific embodiment, the paper machine screening refers to pulp screening in the screening section of the paper machine. The paper machine screen used is a MODUScreen HB5E, equipped with a 90kW motor, and the screen frame has 1.6mm openings, with a screening area of ​​5.87m². 2 The MODUScreen HB5E is an internal flow pressure screen used for screening feed slurry. The slurry enters from the upper part of the screen and forms a good slurry and a bad slurry stream as it moves downwards. The good slurry and the bad slurry are removed from the bottom of the screen.

[0036] In the method provided by the present invention, in a specific embodiment, the equipment for the dewatering and forming of the web is a Fourdrinier with DuoFormmet D. The forming of the paper web begins from the long web forming machine with a top web, where the suspended fiber body begins to dewater.

[0037] In the method provided by this invention, in a specific embodiment, the pressing is carried out in the press section of a paper machine, with a designed machine speed of 1400 m / min and a paper width of 5550 mm in the press section. In this invention, the press section mainly draws the paper from the wire section, removes some moisture under the action of two pressing zones, thereby making the paper sheet more compact, and then the paper sheet is transferred from the press section to the drying section.

[0038] In the method provided by this invention, in a specific embodiment, the pre-drying is a cordless paper feeding process, carried out in the pre-drying section of the paper machine. The drying section frame consists of steel or cast iron box-type structural columns and connecting beams. To facilitate the cleaning of waste paper and improve ventilation, the frame is designed to be as open as possible. The drying cylinder diameter × roll shell length is 1830 × 6850 mm, the roll surface material is cast iron, equipped with 15 drive shafts and 2 drive pins, the 26# cover material is chromium, and the drainage method is fixed siphon drainage. The design pressure is 0.5 MPa, the design temperature is 232℃, the maximum operating pressure is 0.52 MPa, the pressure test pressure is 1.04 MPa, and the maximum operating temperature is 232℃. The dryer roll diameter × roll shell length is 550 × 7100 mm, and the roll shell material is steel.

[0039] In the method provided by this invention, the surface sizing process specifically includes: sequentially coating a surface sizing agent and a coating onto the paper surface. In this invention, the surface sizing agent is preferably a starch solution, and the concentration of the starch solution is preferably 10-20 wt%, specifically 10 wt%, 11 wt%, 12 wt%, 13 wt%, 14 wt%, 15 wt%, 16 wt%, 17 wt%, 18 wt%, 19 wt%, or 20 wt%; the starch solution preferably also contains a lubricant; and the dry coating amount of the surface sizing agent is preferably 1-2 g / m². 2 Specifically, it can be 1g / m 2 1.1g / m 2 1.2g / m 2 1.3g / m 2 1.4g / m 2 1.5g / m 2 1.6g / m 2 1.7g / m 2 1.8g / m 2 1.9g / m 2 or 2g / m 2 In this invention, the coating preferably comprises titanium dioxide, polyvinyl alcohol, starch, lubricant, and water-resistant agent; wherein, based on 100 parts by weight of titanium dioxide in the coating, the polyvinyl alcohol content in the coating is preferably 5-10 parts by weight, specifically 5, 6, 7, 8, 9, or 10 parts by weight; the starch content in the coating is preferably 20-30 parts by weight, specifically 20, 21, 22, 23, 24, 25, or 26 parts by weight. The coating contains 27, 28, 29, or 30 parts by weight; the lubricant content in the coating is preferably 0.2 to 0.6 parts by weight, specifically 0.2, 0.3, 0.4, 0.5, or 0.6 parts by weight; the water-resistant agent content in the coating is preferably 0.3 to 0.6 parts by weight, specifically 0.3, 0.35, 0.4, 0.45, 0.5, 0.55, or 0.6 parts by weight; the coating amount is preferably 3 to 5 g / m². 2 Specifically, it can be 3g / m 2 3.5g / m 2 4g / m 2 4.5g / m 2 or 5g / m 2 .

[0040] In the method provided by this invention, in a specific embodiment, the post-drying is achieved by a paper-feeding rope system, which is carried out in the post-drying section of the paper machine. The drying section frame consists of steel or cast iron box-type structural columns and connecting beams. To facilitate the cleaning of waste paper and improve ventilation, the frame is designed to be as open as possible. The drying cylinder diameter × roll shell length is 1830 × 6850 mm, the roll surface material is cast iron, and it is equipped with 15 drive shafts and 2 drive pins. The 26# cover material is chromium, and the drainage method is a fixed siphon drainage. The design pressure is 0.5 MPa, the design temperature is 232℃, the maximum operating pressure is 0.52 MPa, the pressure test pressure is 1.04 MPa, and the maximum operating temperature is 232℃. The dryer roll diameter × roll shell length is 550 × 7100 mm, and the roll shell material is steel.

[0041] In the method provided by this invention, in a specific embodiment, the calendering is performed in a hard calendering machine with a linear pressure of 4-60 kN / m and a single pressure zone of 1 nip; the lower calendering roller is a Symcds / HP model, which is a multi-pressure zone controllable roller with a specification of ф710X7010mm; the upper calendering roller is a hot roller with a specification of ф860X6730mm and a surface hardness of 580±20HV.

[0042] In the method provided by the present invention, the smoothness of the journal paper is preferably 50 to 70s, specifically 50s, 51s, 52s, 53s, 54s, 55s, 56s, 57s, 58s, 59s, 60s, 61s, 62s, 63s, 64s, 65s, 66s, 67s, 68s, 69s or 70s.

[0043] In the method provided by the present invention, the static friction coefficient of the journal paper is preferably 0.4 to 0.55, specifically 0.4, 0.41, 0.42, 0.43, 0.44, 0.45, 0.46, 0.47, 0.48, 0.49, 0.5, 0.51, 0.52, 0.53, 0.54 or 0.55.

[0044] In the method provided by the present invention, the coefficient of dynamic friction of the journal paper is preferably 0.35 to 0.5, specifically 0.35, 0.36, 0.37, 0.38, 0.39, 0.4, 0.41, 0.42, 0.43, 0.44, 0.45, 0.46, 0.47, 0.48, 0.49 or 0.5.

[0045] In the method provided by the present invention, the surface strength of the journal paper is preferably 1 to 2 m / s, specifically 1 m / s, 1.1 m / s, 1.2 m / s, 1.3 m / s, 1.4 m / s, 1.5 m / s, 1.6 m / s, 1.7 m / s, 1.8 m / s, 1.9 m / s or 2 m / s.

[0046] In the method provided by the present invention, the surface area of ​​the journal paper is preferably 75-90% ISO, specifically 75% ISO, 76% ISO, 77% ISO, 78% ISO, 79% ISO, 80% ISO, 81% ISO, 82% ISO, 83% ISO, 84% ISO, 85% ISO, 86% ISO, 87% ISO, 88% ISO, 89% ISO or 90% ISO.

[0047] In the method provided by the present invention, the longitudinal tear length of the journal paper is preferably 4500-5500m, specifically 4500m, 4600m, 4700m, 4800m, 4900m, 5000m, 5100m, 5200m, 5300m, 5400m or 5500m.

[0048] In the method provided by this invention, the journal paper has a g / m³ content of 80 g / m³. 2 The longitudinal bending stiffness of the product is preferably 80-90 mN, specifically 80 mN, 81 mN, 82 mN, 83 mN, 84 mN, 85 mN, 86 mN, 87 mN, 88 mN, 89 mN, or 90 mN; the 80 g / m² of the journal paper... 2 The lateral bending stiffness of the product is preferably 50-60mN, specifically 50mN, 51mN, 52mN, 53mN, 54mN, 55mN, 56mN, 57mN, 58mN, 59mN or 60mN.

[0049] In the method provided by this invention, the 100g / m² of the journal paper 2 The longitudinal bending stiffness of the product is preferably 140-160 mN, specifically 140 mN, 141 mN, 142 mN, 143 mN, 144 mN, 145 mN, 146 mN, 147 mN, 148 mN, 149 mN, 150 mN, 151 mN, 152 mN, 153 mN, 154 mN, 155 mN, 156 mN, 157 mN, 158 mN, 159 mN, or 160 mN; the 100 g / m² of the journal paper... 2 The lateral bending stiffness of the product is preferably 65-80mN, specifically 65mN, 66mN, 67mN, 68mN, 69mN, 70mN, 71mN, 72mN, 73mN, 74mN, 75mN, 76mN, 77mN, 78mN, 79mN or 80mN.

[0050] For clarity, the following examples will be used to provide a detailed description.

[0051] Example 1

[0052] A method for manufacturing journal paper involves blending bleached sulfate softwood chemical pulp, bleached sulfate hardwood chemical pulp, and alkaline hydrogen peroxide bleached poplar mechanical pulp (APMP) as fiber raw materials. The process includes thick pulp screening, conditioning, rinsing, sand and gas removal, sizing, paper machine screening, wire section dewatering and forming, pressing, pre-drying, surface sizing, post-drying, calendering, winding, and packaging. Key preparation processes and conditions are described below; other preparation processes and conditions have been described previously and will not be repeated.

[0053] (1) In the mixing section, bleached sulfate softwood chemical pulp is pulped to 47°SR. During the pulping process, 0.3 kg of PAM (polyacrylamide) is added per ton of bleached sulfate softwood chemical pulp. Bleached sulfate hardwood chemical pulp is pulped to 39°SR. During the pulping process, 0.3 kg of PAM (polyacrylamide) is added per ton of bleached sulfate hardwood chemical pulp. Alkaline hydrogen peroxide bleached poplar mechanical pulp (APMP) is not pulped. Bleached sulfate softwood chemical pulp, bleached sulfate hardwood chemical pulp and alkaline hydrogen peroxide bleached poplar mechanical pulp (APMP) are mixed into a pulp, and the concentration is adjusted to 3.2 wt%. The pulp weight ratio is: bleached sulfate softwood chemical pulp 40%, bleached sulfate hardwood chemical pulp 50%, APMP 10%.

[0054] (2) In the pulping and related sections, fillers are added to the wet end of the paper machine. The fillers are calcium silicate and calcined kaolin. The particle size of calcium silicate is 3-5 μm and the whiteness is 85%. The particle size of calcined kaolin is 2-4 μm and the whiteness is 88%. The ratio of the two is 1:1 and the amount of filler is 25 wt%. The auxiliary materials are added by metering pump: 28 kg / ton of paper of sizing agent (alkyl ketene dimer), 0.3 kg / ton of paper of retention aid (polyacrylamide), 6 kg / ton of paper of cationic starch, and 20 kg / ton of paper of wet strength agent (polyamide epichlorohydrin resin). The mixture is mixed evenly and diluted to a concentration of 2.4 wt%. The pulp is then screened to remove sand and diluted with fine pulp. The pulp concentration on the wire is 0.9 wt%. The opening of the headbox lip is controlled at 10.0 mm and the headbox pressure is controlled at 56.0 kPa. The wet paper sheet is formed on the wire.

[0055] (3) In the surface sizing section, a surface sizing agent and a coating are applied sequentially to the paper surface; the surface sizing agent is a 14wt% starch solution with a lubricant added, and the application rate is 1.5g / m². 2 The coating composition includes: 100 parts by weight of titanium dioxide (particle size 1-2 μm), 7 parts by weight of PVA (polyvinyl alcohol), 25 parts by weight of starch, 0.3 parts by weight of lubricant, and 0.4 parts by weight of water-resistant agent (polyamide polyurea resin). The coating weight is 3 g / m². 2 .

[0056] The product tested showed a static friction coefficient below 0.45 and a dynamic friction coefficient below 0.40; smoothness ≥ 65s; surface strength ≥ 1.2m / s; paper color white with a whiteness of 80-84% ISO; longitudinal breaking length ≥ 4800m; and a g / m² content of 80g. 2 The product's longitudinal bending stiffness is ≥85mN, and its transverse bending stiffness is ≥55mN; 100g / m 2 The product's longitudinal bending stiffness is ≥150mN, and its transverse bending stiffness is ≥70mN.

[0057] Example 2

[0058] A method for manufacturing journal paper involves blending bleached sulfate softwood chemical pulp, bleached sulfate hardwood chemical pulp, and alkaline hydrogen peroxide bleached poplar mechanical pulp (APMP) as fiber raw materials. The process includes thick pulp screening, conditioning, rinsing, sand and gas removal, sizing, paper machine screening, wire section dewatering and forming, pressing, pre-drying, surface sizing, post-drying, calendering, winding, and packaging. Key preparation processes and conditions are described below; other preparation processes and conditions have been described previously and will not be repeated.

[0059] (1) In the mixing section, the bleached sulfate softwood chemical pulp is pulped to 48°SR. During the pulping process, 0.5 kg PAM (polyacrylamide) is added per ton of the bleached sulfate softwood chemical pulp. The bleached sulfate hardwood chemical pulp is pulped to 40°SR. During the pulping process, 0.5 kg PAM (polyacrylamide) is added per ton of the bleached sulfate hardwood chemical pulp. The alkaline hydrogen peroxide bleached poplar mechanical pulp (APMP) is not pulped. The bleached sulfate softwood chemical pulp, bleached sulfate hardwood chemical pulp and alkaline hydrogen peroxide bleached poplar mechanical pulp (APMP) are mixed into a pulp, and the concentration is adjusted to 3.5 wt%. The pulp weight ratio is: bleached sulfate softwood chemical pulp 40%, bleached sulfate hardwood chemical pulp 50%, APMP 10%.

[0060] (2) In the pulping and related sections, fillers are added to the wet end of the paper machine. The fillers are calcium silicate and calcined kaolin. The particle size of calcium silicate is 3-5 μm and the whiteness is 85%. The particle size of calcined kaolin is 2-4 μm and the whiteness is 88%. The ratio of the two is 1:1 and the amount of filler is 25 wt%. The auxiliary materials are added by metering pump: 30 kg / ton of paper of sizing agent (alkyl ketene dimer), 0.5 kg / ton of paper of retention aid (polyacrylamide), 8 kg / ton of paper of cationic starch, and 22 kg / ton of paper of wet strength agent (polyamide epichlorohydrin resin). The mixture is mixed evenly and diluted to a concentration of 2.6 wt%. The pulp is then screened to remove sand and diluted with fine pulp. The pulp concentration on the wire is 1.0 wt%. The opening of the headbox lip plate is controlled at 10.5 mm and the headbox pressure is controlled at 57.0 kPa. The wet paper sheet is formed on the wire.

[0061] (3) In the surface sizing section, a surface sizing agent and a coating are applied sequentially to the paper surface; the surface sizing agent is a 15wt% starch solution with a lubricant added, and the application rate is 1.8g / m². 2 The coating composition includes: 100 parts by weight of titanium dioxide (particle size 1-2 μm), 10 parts by weight of PVA (polyvinyl alcohol), 30 parts by weight of starch, 0.6 parts by weight of lubricant, and 0.6 parts by weight of water-resistant agent (polyamide polyurea resin). The coating weight is 5 g / m². 2 .

[0062] The product tested showed a static friction coefficient below 0.5 and a dynamic friction coefficient below 0.45; smoothness ≥70s; surface strength ≥1.5m / s; paper color white with a whiteness of 80-84% ISO; longitudinal breaking length ≥4900m; and a g / m² content of 80g. 2 The product's longitudinal bending stiffness is ≥86mN, and its transverse bending stiffness is ≥56mN; 100g / m 2 The product's longitudinal bending stiffness is ≥155mN, and its transverse bending stiffness is ≥75mN.

[0063] In this invention, the journal paper produced using the method described in the above embodiments achieves ultra-high opacity, uniform thickness, good evenness, high smoothness, and long-term preservation. Specifically, the thickness deviation across the horizontal width is within 1 g / m². 2 Within this range, the paper smoothness reaches 70s or more, and the paper aging value is less than 0.2% (after 48 hours at 105℃, the change in folding endurance is tested, and the actual percentage decrease in folding endurance is less than 0.2%).

[0064] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for manufacturing journal paper, characterized in that, Includes the following steps: Wood pulp is mixed and then screened, seasoned, rinsed, desanded and deaerated, coated, screened on the paper machine, dewatered and formed on the wire section, pressed, pre-dried, surface sizing, post-dried, and calendered to obtain journal paper. The specific process of papermaking includes: adding polyacrylamide to bleached sulfate softwood chemical pulp at an addition rate of 0.3~0.6 kg / ton of pulp, and beating it to obtain bleached sulfate softwood chemical pulp with a freeness of 46~48ºSR; adding polyacrylamide to bleached sulfate hardwood chemical pulp at an addition rate of 0.3~0.6 kg / ton of pulp, and beating it to obtain bleached sulfate hardwood chemical pulp with a freeness of 38~40ºSR; mixing the bleached sulfate softwood chemical pulp with a freeness of 46~48ºSR, the bleached sulfate hardwood chemical pulp with a freeness of 38~40ºSR, and alkaline hydrogen peroxide bleached poplar mechanical pulp with a freeness of 50~52ºSR at a mass ratio of (3~5):(4~6):1, adjusting the concentration to obtain concentrated paper pulp; During the pulping process, fillers are added to the pulp. The fillers are calcium silicate and calcined kaolin, with a mass ratio of calcium silicate to calcined kaolin of 1:(0.5~2). The filler content in the journal paper is 25~30wt%. During the pulping process, auxiliary materials are also added to the pulp. The auxiliary materials include internal sizing agent, retention aid, cationic starch, and wet strength agent. The amount of internal sizing agent added is 28~32kg / ton of paper, the amount of retention aid added is 0.3~0.6kg / ton of paper, the amount of cationic starch added is 6~8kg / ton of paper, and the amount of wet strength agent added is 20~26kg / ton of paper. The surface sizing process specifically includes: sequentially applying a surface sizing agent and a coating to the paper surface; wherein, by weight, the coating comprises 100 parts titanium dioxide, 5-10 parts polyvinyl alcohol, 20-30 parts starch, 0.2-0.6 parts lubricant, and 0.3-0.6 parts water-resistant agent, and the coating amount is 3-5 g / m². 2 .

2. The manufacturing method according to claim 1, characterized in that, The bleached sulfate softwood chemical pulp with a freeness of 46-48ºSR, the bleached sulfate hardwood chemical pulp with a freeness of 38-40ºSR, and the alkaline hydrogen peroxide bleached poplar mechanical pulp with a freeness of 50-52ºSR are mixed at a mass ratio of 4:5:

1.

3. The manufacturing method according to claim 1, characterized in that, The concentration of the paper pulp is 3.1~3.9 wt%.

4. The manufacturing method according to claim 1, characterized in that, The mass ratio of calcium silicate to calcined kaolin is 1:

1.

5. The manufacturing method according to claim 1, characterized in that, The surface sizing agent is a starch adhesive solution with a concentration of 10-20 wt%; the dry coating weight of the surface sizing agent is 1-2 g / m². 2 .

6. The manufacturing method according to claim 5, characterized in that, The starch solution also contains a lubricant.

7. The manufacturing method according to any one of claims 1 to 6, characterized in that, The smoothness of the journal paper is 50~70s.