A high-performance digital paper manufacturing method

Abstract

The application provides a high-performance digital paper making method, which comprises the following steps: mixing sulfate needle wood pulp, bleached sulfate broadleaf wood pulp and alkaline peroxide mechanical pulp into pulp mixture liquid, then adding modified ground calcium carbonate and positive starch into the pulp mixture liquid and fully mixing to obtain raw paper pulp to produce raw paper, performing surface sizing on the raw paper, performing coating by using film transfer double-sided coating, performing calendering to modify the paper surface, and finally performing coating by using a treatment liquid, so that the high-performance digital paper is obtained. By combining the modified calcium carbonate, the starch glue liquid, the reasonable coating raw material ratio and the suitable treatment liquid, the performance of the paper can be enhanced, the digital paper can quickly absorb the water-based ink, the ink adhesion is strong, and the color restoration is strong. In addition, the high-performance digital paper developed by the application can replace the solvent type ink with the water-based ink, so that the pollution of the organic solvent to the environment can be avoided, and the development trend of the world green environmental protection can be adapted.

Description

Technical Field

[0001] This invention relates to the field of papermaking technology, and in particular to a high-performance digital papermaking method. Background Technology

[0002] Digital paper, as an innovative material, has broad application prospects in the printing field. Good printability is a core technical requirement for digital paper, which determines its performance and effect during the printing process.

[0003] With the widespread adoption of computers and the internet, and growing concern for environmental quality, digital inkjet printing, especially water-based inkjet printing, is poised to challenge or replace traditional printing technologies that primarily use solvent-based inks. Faced with this booming technology, the paper industry must see itself as a crucial link in this "digital inkjet printing" system. It must closely monitor the performance requirements of new digital inkjet printing technologies, continuously adjust paper composition and surface treatment methods to upgrade existing paper products, and develop new paper products to better adapt to the rapid development of digital inkjet printing.

[0004] High-end digital paper needs to possess the following superior properties:

[0005] ① Rapid Drying Performance: Digital inkjet printing uses water-based inks as a medium to impact or replace traditional printing technologies that primarily use solvent-based inks, requiring paper to have a rapid drying time for water-based inks. ② Surface Smoothness and Color Reproduction: Digital paper needs a highly smooth surface to ensure delicate image and text effects and high color reproduction. This places high demands on paper quality and manufacturing processes. ③ Abrasion Resistance and Water Resistance: Digital paper needs a certain degree of abrasion resistance during the printing process to ensure the durability of print quality. Simultaneously, digital paper also needs a certain degree of water resistance to cope with humidity changes and water-based inks during printing. ④ Compatibility with Pre-coating Liquid: Inkjet digital paper is generally coated with a pre-coating liquid before printing to improve printing performance; therefore, the printing base paper must have good compatibility with the pre-coating liquid. ⑤ Printing Speed ​​and Precision: Digital paper needs to be able to adapt to the requirements of high-speed printing equipment to achieve fast and precise printing. This places high demands on paper strength and flatness. ⑥ Sustainability and Environmental Friendliness: Digital paper needs to be sustainable and environmentally friendly to meet the modern printing industry's demand for environmentally friendly materials. This presents challenges to the selection of paper materials and production processes. Summary of the Invention

[0006] In view of this, the present invention proposes a high-performance digital paper manufacturing method.

[0007] The technical solution of this invention is implemented as follows:

[0008] A high-performance digital paper manufacturing method includes the following steps:

[0009] S1: Take sulfate softwood pulp, bleached sulfate hardwood pulp and alkaline hydrogen peroxide mechanical pulp, and mix them in a weight ratio of 65~70:5~12:15~30 to form a pulp mixture;

[0010] S2: In the pulp mixture of step S1, modified ground calcium carbonate and positively charged starch are added and thoroughly mixed at a rotation speed of 600-800 r / min to obtain base paper pulp; by weight ratio, the base paper pulp includes 70-80% pulp mixture, 12-30% modified ground calcium carbonate, and 0.6-1.0% positively charged starch; the wire speed is 1200-1300 m / min; the modified ground calcium carbonate includes the following raw materials in parts by weight: 50-60 parts ground calcium carbonate, 2-4 parts fatty acid polyvinyl alcohol, 2-4 parts silane coupling agent, 0.5-1.6 parts calcium stearate, and 280-320 parts water;

[0011] S3: Use the pulp obtained in step S2 to produce base paper, with a basis weight of 160~180 g / m³. 2 The moisture content is 4-8%;

[0012] S4: Apply starch sizing solution to the surface of the base paper using a film transfer double-sided sizing process. The low shear viscosity is 10~14 cps, and the total sizing amount is 2~3 g / m³. 2 The resulting surface-sizing base paper is obtained; the starch adhesive comprises the following raw materials in parts by weight: 70-80 parts starch, 15-20 parts polyacrylamide, 8-12 parts polyvinyl alcohol, 8-12 parts water-soluble cellulose ether, 4-7 parts sodium hexametaphosphate, and 800-900 parts water.

[0013] S5: A single-coating process is used to apply a double-sided film transfer coating to the sizing paper to obtain a single-coated paper; the film transfer coating amount is 10~20 g / m². 2 The pressure of the primer metering bar is 1.4~1.8 / 1.4~1.8 bar for the upper and lower rollers respectively.

[0014] S6: A second primer coating is applied to the primary primer paper using a double-sided film transfer coating method to obtain a secondary primer paper; the film transfer coating amount is 8~18 g / m². 2 The pressure of the base coat metering bar is 1.4~1.8 / 1.4~1.8 bar for the upper and lower rollers, respectively. S7: The secondary base coat paper undergoes two doctor blade coatings, one coat per layer, followed by an intermediate coat; this results in the intermediate coat paper. The doctor blade pressure for the intermediate coat is 35~60%, and the total coating weight is 18~24 g / m². 2 ;

[0015] S8: Apply two doctor blade coatings to the intermediate coating paper, one side at a time, to obtain the top-coated paper; the doctor blade pressure for the top coating is 30~55%, and the total coating amount is 16~22g / m². 2 ;

[0016] S9: The coated paper is calendered and finished using a supercalender. The supercalender uses the 4th and 9th pressure zones to calender the paper at a calendering temperature of 40~60℃ and a linear pressure of 70~90kN / m to produce digital paper base paper.

[0017] S10: The digital paper base paper is coated with a treatment solution to obtain high-performance digital paper; the coating amount of the treatment solution is 0.3~5g, and the solid content of the treatment solution is 20~40%; the treatment solution includes, by weight: 60~80 parts of triamic acid, 20~30 parts of diethylene glycol-butyl ether, 10~20 parts of phosphoric acid, 1~5 parts of benzotriazole, and 0.1~1 parts of ethanol.

[0018] Furthermore, in step S2, the preparation process of the modified ground calcium carbonate is as follows: silane coupling agent and fatty acid polyvinyl alcohol are added to water and stirred for 4 to 5 minutes at a speed of 500 to 600 r / min. Then, ground calcium carbonate and calcium stearate are added and stirred for 5 to 6 minutes at a speed of 800 to 1000 r / min to obtain modified ground calcium carbonate.

[0019] Furthermore, in step S4, the starch is one or both of corn starch and tapioca starch.

[0020] Further, in step S4, the preparation process of the starch adhesive is as follows: starch and 20-30% water of the total amount are stirred and mixed at a speed of 600-800 r / min, then polyvinyl alcohol is added and stirred and mixed at a speed of 600-800 r / min, the temperature is raised to 90-95℃ and reacted for 15-20 min, the temperature is lowered to 35-40℃, the remaining water is added and mixed at a speed of 600-800 r / min, then sodium hexametaphosphate, water-soluble cellulose ether and polyacrylamide are added in sequence and stirred and mixed to obtain the starch adhesive.

[0021] Furthermore, in steps S5 and S6, the coatings for the primary and secondary primers comprise the following raw materials in parts by weight: 20-28 parts of ground calcium carbonate grade 60, 36-42 parts of ground calcium carbonate grade 65, 1-3 parts of silane coupling agent, 8-10 parts of hydroxypropyl starch, 12-15 parts of vinyl acetate-ethylene copolymer latex, 0.5-1.0 parts of polydimethylsiloxane, 0.10-0.16 parts of sodium polyacrylate, 0.05-0.08 parts of tert-butanol, and 50-60 parts of water.

[0022] Furthermore, the preparation process of the primary and secondary primers is as follows: under a stirring speed of 300-400 r / min, polydimethylsiloxane, sodium polyacrylate, and tert-butanol are added to water and stirred for 5-6 minutes. Then, grade 60 and grade 65 ground calcium carbonate are added and stirred until homogeneous. Next, a silane coupling agent is added and stirred until homogeneous. Finally, hydroxypropyl starch and vinyl acetate-ethylene copolymer latex are added and stirred until homogeneous at a speed of 700-800 r / min to obtain the coating.

[0023] Furthermore, in step S7, the intermediate coating comprises the following raw materials in parts by weight: 40-46 parts of ground calcium carbonate grade 60, 36-40 parts of ground calcium carbonate grade 65, 2-4 parts of silane coupling agent, 8-10 parts of hydroxypropyl starch, 9-11 parts of bio-latex, 1-1.5 parts of polydimethylsiloxane, 0.08-0.15 parts of sodium polyacrylate, 0.05-0.08 parts of tert-butanol, and 50-70 parts of water.

[0024] Furthermore, the preparation process of the topcoat is as follows: under the condition of stirring speed of 300~400r / min, polydimethylsiloxane, sodium polyacrylate and tert-butanol are added to water and stirred for 5~6min. Then, 65 grade and 98 grade ground calcium carbonate are added and stirred until mixed. Then, silane coupling agent is added and stirred until mixed. Finally, hydroxypropyl starch and bio-latex are added and stirred until mixed at a speed of 700~800r / min to obtain the coating.

[0025] Furthermore, in step S8, the coating material for the topcoat comprises the following raw materials in parts by weight: 40-46 parts of ground calcium carbonate grade 65, 30-38 parts of ground calcium carbonate grade 98, 3-5 parts of silane coupling agent, 10-15 parts of hydroxypropyl starch, 8-11 parts of vinyl acetate-ethylene copolymer latex, 0.5-1.2 parts of polydimethylsiloxane, 0.08-0.15 parts of sodium polyacrylate, 0.05-0.08 parts of tert-butanol, and 40-60 parts of water.

[0026] Furthermore, the preparation process of the topcoat is as follows: under a stirring speed of 300~400 r / min, polydimethylsiloxane, sodium polyacrylate, and tert-butanol are added to water and stirred for 5~6 min. Then, 65 grade and 98 grade ground calcium carbonate are added and stirred until mixed. Next, a silane coupling agent is added and stirred until mixed. Finally, hydroxypropyl starch and vinyl acetate-ethylene copolymer latex are added and stirred until mixed at a speed of 700~800 r / min to obtain the coating.

[0027] Furthermore, the content of the ground calcium carbonate C60 with particles smaller than 2 μm is 60-62%; the content of the ground calcium carbonate C65 with particles smaller than 2 μm is 64-66%.

[0028] Furthermore, the ground calcium carbonate C65 has a particle size of less than 2 μm and a particle content of 64-66%; the ground calcium carbonate C98 has a particle size of less than 2 μm and a particle content of 98-100%.

[0029] Compared with the prior art, the beneficial effects of the present invention are:

[0030] This invention enhances paper performance by combining modified calcium carbonate, starch slurry, and a reasonable ratio of coating raw materials with a suitable treatment liquid. The resulting paper is fine, smooth, and has high whiteness. The digital paper can also quickly absorb water-based inks, resulting in strong ink adhesion, no diffusion, strong color reproduction, and fast drying speed. It does not smudge during printing. Water-based inks replace solvent-based inks, avoiding the environmental pollution caused by organic solvents, making it green and environmentally friendly.

[0031] In the process of preparing high-performance digital paper, this invention uses a combination of fatty acid polyvinyl alcohol, silane coupling agent and calcium stearate to modify ground calcium carbonate, which can improve the dispersion of ground calcium carbonate in pulp and increase the penetration and compatibility of ground calcium carbonate with other raw materials, making the paper more delicate and smooth, and also improving the ink absorption and drying time, resulting in excellent performance.

[0032] In the preparation of starch adhesive, starch is compounded with polyacrylamide, polyvinyl alcohol and water-soluble cellulose ether to form a cross-linked, water-permeable network structure. This structure can ensure the tensile and folding strength of paper while promoting the penetration and absorption of water-based inks, preventing diffusion and improving printing results.

[0033] The production process of the high-performance digital paper of this invention complies with relevant laws and regulations, as well as national environmental protection requirements and emission standards. Detailed Implementation

[0034] To better understand the technical content of this invention, specific embodiments are provided below to further illustrate the invention.

[0035] Unless otherwise specified, the experimental methods used in the embodiments of this invention are all conventional methods.

[0036] Unless otherwise specified, all materials and reagents used in the embodiments of this invention are commercially available.

[0037] Example 1

[0038] The high-performance digital paper manufacturing method of this embodiment includes the following steps:

[0039] S1: Take sulfate softwood pulp, bleached sulfate hardwood pulp and alkaline hydrogen peroxide mechanical pulp, and mix them in a weight ratio of 65:8:30 to form a pulp mixture;

[0040] S2: In the pulp mixture of step S1, modified ground calcium carbonate and positive starch are added and thoroughly mixed at a rotation speed of 800 r / min to obtain base paper pulp; by weight ratio, the base paper pulp includes 75% pulp mixture, 24.4% modified ground calcium carbonate, and 0.6% positive starch; the wire speed is 1300 m / min; the modified ground calcium carbonate includes the following raw materials in parts by weight: 60 parts ground calcium carbonate, 3 parts fatty acid polyvinyl alcohol, 2 parts silane coupling agent, 1.6 parts calcium stearate, and 320 parts water; the preparation process of the modified ground calcium carbonate is as follows: the silane coupling agent and fatty acid polyvinyl alcohol are added to water and stirred at a rotation speed of 600 r / min for 5 min, then the ground calcium carbonate and calcium stearate are added and stirred at a rotation speed of 800 r / min for 6 min to obtain the modified ground calcium carbonate;

[0041] S3: Use the pulp obtained in step S2 to produce base paper, and the basis weight of the resulting base paper is 160 g / m³. 2 Of which, the moisture content is 7%;

[0042] S4: The starch sizing solution is applied to the surface of the base paper using a film transfer double-sided sizing process. The low shear viscosity is 12 cps, and the total sizing amount is 2.5 g / m². 2 The resulting surface-sizing base paper is obtained. The starch solution comprises the following raw materials in parts by weight: 80 parts corn starch, 15 parts polyacrylamide, 8 parts polyvinyl alcohol, 10 parts water-soluble cellulose ether, 5 parts sodium hexametaphosphate, and 800 parts water. The preparation process of the starch solution is as follows: starch and 20% of the total amount of water are stirred and mixed at a speed of 600 r / min. Then, polyvinyl alcohol is added and stirred and mixed at a speed of 600 r / min. The mixture is heated to 90°C and reacted for 15 min. The temperature is then lowered to 35°C. The remaining water is added and mixed at a speed of 600 r / min. Then, sodium hexametaphosphate, water-soluble cellulose ether, and polyacrylamide are added sequentially and stirred and mixed to obtain the starch solution.

[0043] S5: A single-coating process is used to apply a double-sided film transfer coating to the sizing paper to obtain a single-coated paper; the film transfer coating amount is 16 g / m². 2 The pressure of the primer metering rod is 1.4 / 1.6 bar for the upper roller and 1.6 bar for the lower roller. The primer coating comprises the following raw materials in parts by weight: 26 parts of ground calcium carbonate grade 60, 42 parts of ground calcium carbonate grade 65, 2 parts of silane coupling agent, 9 parts of hydroxypropyl starch, 15 parts of vinyl acetate-ethylene copolymer latex, 0.5 parts of polydimethylsiloxane, 0.10 parts of sodium polyacrylate, 0.05 parts of tert-butanol, and 60 parts of water. The ground calcium carbonate C60 has a particle size of less than 2 μm and a particle content of 60%. The ground calcium carbonate C65 has a particle size of less than 2 μm and a particle content of 65%.

[0044] S6: A second primer coating is applied to the primary primer paper using a double-sided film transfer coating method to obtain a secondary primer paper; the film transfer coating amount is 12 g / m². 2 The pressure of the primer metering rod is 1.8 / 1.8 bar for the upper and lower rollers. The secondary primer coating comprises the following raw materials in parts by weight: 25 parts of ground calcium carbonate grade 60, 40 parts of ground calcium carbonate grade 65, 1 part of silane coupling agent, 9 parts of hydroxypropyl starch, 14 parts of vinyl acetate-ethylene copolymer latex, 0.8 parts of polydimethylsiloxane, 0.12 parts of sodium polyacrylate, 0.06 parts of tert-butanol, and 52 parts of water. The ground calcium carbonate C60 has a particle size of less than 2 μm and a particle content of 60%. The ground calcium carbonate C65 has a particle size of less than 2 μm and a particle content of 65%.

[0045] S7: Apply two doctor blade coatings to the secondary base-coated paper, one side at a time, followed by an intermediate coating; this results in intermediate-coated paper; the doctor blade pressure for the intermediate coating is 60%, and the total coating amount is 20g / m². 2 The intermediate coating comprises the following raw materials in parts by weight: 45 parts of ground calcium carbonate grade 60, 36 parts of ground calcium carbonate grade 65, 3 parts of silane coupling agent, 8 parts of hydroxypropyl starch, 11 parts of bio-latex, 1.2 parts of polydimethylsiloxane, 0.13 parts of sodium polyacrylate, 0.08 parts of tert-butanol, and 64 parts of water; the ground calcium carbonate C60 has a particle size of less than 2 μm and a content of 60%; the ground calcium carbonate C65 has a particle size of less than 2 μm and a content of 65%.

[0046] S8: Apply two doctor blade coatings to the intermediate coating paper, one side at a time, to obtain the top-coated paper; the doctor blade pressure for the top coating is 30%, and the total coating amount is 18g / m². 2 The topcoat comprises the following raw materials in parts by weight: 43 parts of ground calcium carbonate grade 65, 38 parts of ground calcium carbonate grade 98, 5 parts of silane coupling agent, 12 parts of hydroxypropyl starch, 8 parts of vinyl acetate-ethylene copolymer latex, 1.1 parts of polydimethylsiloxane, 0.12 parts of sodium polyacrylate, 0.08 parts of tert-butanol, and 50 parts of water; the ground calcium carbonate C65 has a particle size of less than 2 μm and ...

[0047] S9: The coated paper is calendered and finished using a supercalender. The supercalender uses the 4th and 9th pressure zones to calender the paper at a calendering temperature of 40℃ and a linear pressure of 80kN / m to produce digital paper base paper.

[0048] S10: The digital paper base paper is coated with a treatment solution to obtain high-performance digital paper; the coating amount of the treatment solution is 3g, and the solid content of the treatment solution is 35%; the treatment solution includes, by weight, 80 parts of triglyceride, 25 parts of diethylene glycol-butyl ether, 16 parts of phosphoric acid, 4 parts of benzotriazole, and 0.8 parts of ethanol.

[0049] Example 2

[0050] The high-performance digital paper manufacturing method of this embodiment includes the following steps:

[0051] S1: Take sulfate softwood pulp, bleached sulfate hardwood pulp and alkaline hydrogen peroxide mechanical pulp, and mix them in a weight ratio of 70:10:18 to form a pulp mixture;

[0052] S2: In the pulp mixture of step S1, modified ground calcium carbonate and positive starch are added and thoroughly mixed at a rotation speed of 600 r / min to obtain base paper pulp; by weight ratio, the base paper pulp includes 77% pulp mixture, 22% modified ground calcium carbonate, and 1.0% positive starch; the wire speed is 1200 m / min; the modified ground calcium carbonate includes the following raw materials in parts by weight: 50 parts ground calcium carbonate, 2 parts fatty acid polyvinyl alcohol, 3.5 parts silane coupling agent, 0.8 parts calcium stearate, and 300 parts water; the preparation process of the modified ground calcium carbonate is as follows: the silane coupling agent and fatty acid polyvinyl alcohol are added to water and stirred at a rotation speed of 550 r / min for 4 min, then the ground calcium carbonate and calcium stearate are added and stirred at a rotation speed of 900 r / min for 5 min to obtain the modified ground calcium carbonate;

[0053] S3: Use the pulp obtained in step S2 to produce base paper, and the basis weight of the resulting base paper is 170 g / m³. 2 Of which, the moisture content is 6%;

[0054] S4: Apply starch sizing solution to the surface of the base paper using a film transfer double-sided sizing process. The low shear viscosity is 10 cps, and the total sizing amount is 2 g / m². 2 The resulting surface-sizing base paper is obtained. The starch solution comprises the following raw materials in parts by weight: 70 parts of starch composed of corn starch and cassava starch in a mass ratio of 1:1, 20 parts of polyacrylamide, 12 parts of polyvinyl alcohol, 9 parts of water-soluble cellulose ether, 6 parts of sodium hexametaphosphate, and 900 parts of water. The preparation process of the starch solution is as follows: starch and 30% of the total amount of water are stirred and mixed at a speed of 800 r / min. Then, polyvinyl alcohol is added and stirred and mixed at a speed of 700 r / min. The mixture is heated to 95°C and reacted for 18 min. The temperature is then lowered to 40°C. The remaining water is added and mixed at a speed of 800 r / min. Then, sodium hexametaphosphate, water-soluble cellulose ether, and polyacrylamide are added sequentially and stirred and mixed to obtain the starch solution.

[0055] S5: A single-coating process is used to apply a double-sided film transfer coating to the sizing paper to obtain a single-coated paper; the film transfer coating amount is 18 g / m². 2The pressure of the primer metering rod is 1.8 / 1.4 bar for the upper roller and 1.4 bar for the lower roller. The primer coating comprises the following raw materials in parts by weight: 20 parts of ground calcium carbonate grade 60, 40 parts of ground calcium carbonate grade 65, 1.5 parts of silane coupling agent, 8 parts of hydroxypropyl starch, 12 parts of vinyl acetate-ethylene copolymer latex, 0.9 parts of polydimethylsiloxane, 0.16 parts of sodium polyacrylate, 0.08 parts of tert-butanol, and 50 parts of water. The ground calcium carbonate C60 has a particle size of less than 2 μm and a particle content of 60%. The ground calcium carbonate C65 has a particle size of less than 2 μm and a particle content of 65%.

[0056] S6: A second primer coating is applied to the primary primer paper using a double-sided film transfer coating method to obtain a secondary primer paper; the film transfer coating amount is 18 g / m². 2 The pressure of the primer metering rod is 1.6 / 1.4 bar for the upper roller and 1.4 bar for the lower roller. The secondary primer coating comprises the following raw materials in parts by weight: 22 parts of ground calcium carbonate grade 60, 37 parts of ground calcium carbonate grade 65, 3 parts of silane coupling agent, 10 parts of hydroxypropyl starch, 15 parts of vinyl acetate-ethylene copolymer latex, 0.7 parts of polydimethylsiloxane, 0.10 parts of sodium polyacrylate, 0.08 parts of tert-butanol, and 58 parts of water. The ground calcium carbonate C60 has a particle size of less than 2 μm and a particle content of 60%. The ground calcium carbonate C65 has a particle size of less than 2 μm and a particle content of 65%.

[0057] S7: Apply two doctor blade coatings to the secondary base-coated paper, one side at a time, followed by an intermediate coating; this results in intermediate-coated paper; the doctor blade pressure for the intermediate coating is 40%, and the total coating amount is 18 g / m². 2 The intermediate coating comprises the following raw materials in parts by weight: 46 parts of ground calcium carbonate grade 60, 38 parts of ground calcium carbonate grade 65, 2.5 parts of silane coupling agent, 9 parts of hydroxypropyl starch, 9 parts of bio-latex, 1.5 parts of polydimethylsiloxane, 0.12 parts of sodium polyacrylate, 0.06 parts of tert-butanol, and 60 parts of water; the ground calcium carbonate C60 has a particle size of less than 2 μm and a content of 60%; the ground calcium carbonate C65 has a particle size of less than 2 μm and a content of 65%.

[0058] S8: Apply two doctor blade coatings to the intermediate coating paper, one side at a time, to obtain the top-coated paper; the doctor blade pressure for the top coating is 40%, and the total coating amount is 22g / m². 2 The topcoat comprises the following raw materials in parts by weight: 42 parts of ground calcium carbonate grade 65, 33 parts of ground calcium carbonate grade 98, 4 parts of silane coupling agent, 13 parts of hydroxypropyl starch, 10 parts of vinyl acetate-ethylene copolymer latex, 1 part of polydimethylsiloxane, 0.09 parts of sodium polyacrylate, 0.07 parts of tert-butanol, and 50 parts of water; the ground calcium carbonate C65 has a particle size of less than 2 μm and ...

[0059] S9: The surface of the coated paper is calendered using a supercalender. The supercalender uses the 4th and 9th pressure zones to calender the paper at a calendering temperature of 60℃ and a linear pressure of 90kN / m to produce digital paper base paper.

[0060] S10: The digital paper base paper is coated with a treatment solution to obtain high-performance digital paper; the coating amount of the treatment solution is 4g, and the solid content of the treatment solution is 40%; the treatment solution includes, by weight, 75 parts of triglyceride, 20 parts of diethylene glycol-butyl ether, 13 parts of phosphoric acid, 5 parts of benzotriazole, and 1 part of ethanol.

[0061] Example 3

[0062] The high-performance digital paper manufacturing method of this embodiment includes the following steps:

[0063] S1: Take sulfate softwood pulp, bleached sulfate hardwood pulp and alkaline hydrogen peroxide mechanical pulp, and mix them in a weight ratio of 68:12:15 to form a pulp mixture;

[0064] S2: In the pulp mixture of step S1, modified ground calcium carbonate and positive starch are added and thoroughly mixed at a rotation speed of 700 r / min to obtain base paper pulp; by weight ratio, the base paper pulp includes 80% pulp mixture, 19.2% modified ground calcium carbonate, and 0.8% positive starch; the wire speed is 1250 m / min; the modified ground calcium carbonate includes the following raw materials in parts by weight: 56 parts ground calcium carbonate, 4 parts fatty acid polyvinyl alcohol, 3 parts silane coupling agent, 1.2 parts calcium stearate, and 280 parts water; the preparation process of the modified ground calcium carbonate is as follows: the silane coupling agent and fatty acid polyvinyl alcohol are added to water and stirred at a rotation speed of 500 r / min for 5 min, then the ground calcium carbonate and calcium stearate are added and stirred at a rotation speed of 1000 r / min for 6 min to obtain the modified ground calcium carbonate;

[0065] S3: Use the pulp obtained in step S2 to produce base paper, and the basis weight of the produced base paper is 180 g / m³. 2 Of which, the moisture content is 8%;

[0066] S4: Apply starch sizing solution to the surface of the base paper using a film transfer double-sided sizing process. The low shear viscosity is 14 cps, and the total sizing amount is 3 g / m³. 2The resulting surface-sizing base paper is obtained. The starch solution comprises the following raw materials in parts by weight: 76 parts of starch composed of corn starch and cassava starch in a mass ratio of 2:1, 18 parts of polyacrylamide, 10 parts of polyvinyl alcohol, 8 parts of water-soluble cellulose ether, 7 parts of sodium hexametaphosphate, and 800 parts of water. The preparation process of the starch solution is as follows: starch and 30% of the total amount of water are stirred and mixed at a speed of 700 r / min. Then, polyvinyl alcohol is added and stirred and mixed at a speed of 800 r / min. The mixture is heated to 90°C and reacted for 20 min. The temperature is then lowered to 35°C, and the remaining water is added and mixed at a speed of 700 r / min. Then, sodium hexametaphosphate, water-soluble cellulose ether, and polyacrylamide are added sequentially and stirred and mixed to obtain the starch solution.

[0067] S5: A single-coating process is used to apply a double-sided film transfer coating to the sizing paper to obtain a single-coated paper; the film transfer coating amount is 20 g / m². 2 The pressure of the primer metering rod is 1.6 / 1.6 bar for the upper and lower rollers. The primer coating comprises the following raw materials in parts by weight: 28 parts of ground calcium carbonate grade 60, 36 parts of ground calcium carbonate grade 65, 3 parts of silane coupling agent, 10 parts of hydroxypropyl starch, 14 parts of vinyl acetate-ethylene copolymer latex, 0.8 parts of polydimethylsiloxane, 0.15 parts of sodium polyacrylate, 0.06 parts of tert-butanol, and 52 parts of water. The ground calcium carbonate C60 has a particle size of less than 2 μm and a particle content of 60%. The ground calcium carbonate C65 has a particle size of less than 2 μm and a particle content of 65%.

[0068] S6: A second primer coating is applied to the primary primer paper using a double-sided film transfer coating method to obtain a secondary primer paper; the film transfer coating amount is 16 g / m². 2 The pressure of the primer metering rod is 1.4 / 1.8 bar for the upper roller and 1.8 bar for the lower roller. The secondary primer coating comprises the following raw materials in parts by weight: 27 parts of ground calcium carbonate grade 60, 42 parts of ground calcium carbonate grade 65, 2.5 parts of silane coupling agent, 9 parts of hydroxypropyl starch, 13 parts of vinyl acetate-ethylene copolymer latex, 1.0 part of polydimethylsiloxane, 0.14 parts of sodium polyacrylate, 0.08 parts of tert-butanol, and 50 parts of water. The ground calcium carbonate C60 has a particle size of less than 2 μm and a particle content of 60%. The ground calcium carbonate C65 has a particle size of less than 2 μm and a particle content of 65%.

[0069] S7: Apply two doctor blade coatings to the secondary base-coated paper, one side at a time, followed by an intermediate coating; this results in intermediate-coated paper; the doctor blade pressure for the intermediate coating is 50%, and the total coating amount is 24 g / m². 2The intermediate coating comprises the following raw materials in parts by weight: 42 parts of ground calcium carbonate grade 60, 40 parts of ground calcium carbonate grade 65, 4 parts of silane coupling agent, 10 parts of hydroxypropyl starch, 10 parts of bio-latex, 1.3 parts of polydimethylsiloxane, 0.15 parts of sodium polyacrylate, 0.07 parts of tert-butanol, and 55 parts of water; the ground calcium carbonate C60 has a particle size of less than 2 μm and ...

[0070] S8: Apply two doctor blade coatings to the intermediate coating paper, one side at a time, to obtain the top-coated paper; the doctor blade pressure for the top coating is 50%, and the total coating amount is 16g / m². 2 The topcoat comprises the following raw materials in parts by weight: 45 parts of ground calcium carbonate grade 65, 35 parts of ground calcium carbonate grade 98, 3 parts of silane coupling agent, 15 parts of hydroxypropyl starch, 9 parts of vinyl acetate-ethylene copolymer latex, 0.9 parts of polydimethylsiloxane, 0.14 parts of sodium polyacrylate, 0.05 parts of tert-butanol, and 49 parts of water; the ground calcium carbonate C65 has a particle size of less than 2 μm and a particle content of 65%; the ground calcium carbonate C98 has a particle size of less than 2 μm and a particle content of 98%.

[0071] S9: The surface of the coated paper is calendered using a supercalender. The supercalender uses the 4th and 9th pressure zones to calender the paper at a calendering temperature of 50℃ and a linear pressure of 70kN / m to produce digital paper base paper.

[0072] S10: The digital paper base paper is coated with a treatment solution to obtain high-performance digital paper; the coating amount of the treatment solution is 2g, and the solid content of the treatment solution is 30%; the treatment solution includes, by weight, 70 parts of triglyceride, 30 parts of diethylene glycol-butyl ether, 18 parts of phosphoric acid, 2 parts of benzotriazole, and 0.3 parts of ethanol.

[0073] Comparative Example 1

[0074] This comparative example is the same as Example 3, except that the ground calcium carbonate was not modified. The only difference is that the modified ground calcium carbonate was replaced with ground calcium carbonate raw material. The S2 step process of this comparative example is as follows:

[0075] S2: Modified ground calcium carbonate and positive starch are added to the pulp mixture in step S1 and mixed thoroughly at a rotation speed of 700 r / min to obtain base paper pulp; by weight ratio, the base paper pulp includes 80% pulp mixture, 19.2% ground calcium carbonate, and 0.8% positive starch; the wire speed is 1250 m / min.

[0076] Comparative Example 2

[0077] This comparative example is based on Example 3, but the raw material composition and ratio of the starch adhesive are adjusted, while the rest is the same as in Example 3.

[0078] The starch solution comprises the following raw materials in parts by weight: 84 parts starch, 28 parts polyvinyl alcohol, 7 parts sodium hexametaphosphate, and 800 parts water.

[0079] The preparation process of the starch adhesive is as follows: starch and 30% of the total amount of water are stirred and mixed at a speed of 700 r / min. Then, polyvinyl alcohol is added and stirred and mixed at a speed of 800 r / min. The mixture is heated to 90℃ and reacted for 20 min. The temperature is then lowered to 35℃, the remaining water is added and mixed at a speed of 700 r / min. Finally, sodium hexametaphosphate is added and stirred and mixed to obtain the starch adhesive.

[0080] The high-performance digital paper prepared according to the methods of Examples 1-3 and Comparative Examples 1-2 above was subjected to performance testing. The test process and methods are as follows:

[0081] (1) Color density: The high-performance digital paper prepared in Examples 1-4 and Comparative Examples 1-2 was printed with CMYK color blocks using a digital printing machine, and the color density of each color block was detected by X-Rite.

[0082] (2) Water absorption: Refer to GB / T 1540-2002;

[0083] (3) Gloss: Refer to T48;

[0084] (4) ISO whiteness: refer to ISO2470;

[0085] The results are shown in Table 1.

[0086] Table 1 Performance test results of high-performance digital paper

[0087]

[0088] The above results demonstrate that the methods of Examples 1-3 of this invention can impart excellent printability to paper. It exhibits good color density, resulting in vibrant colors, rich ink coverage, strong ink adhesion, and excellent color reproduction during printing. Furthermore, it demonstrates good water absorption, allowing for rapid ink penetration, absorption, and drying without diffusion, with drying times all less than 5 seconds. Compared to Example 3, Comparative Example 1 did not modify the ground calcium carbonate, and Comparative Example 2 had different raw material ratios for the starch slurry, leading to a decrease in paper gloss and whiteness, a decrease in paper color density, and a slower rate of absorption and drying of water-based inks during printing.

[0089] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A high performance digital paper making method, characterized by, The method comprises the following steps: S1: taking sulfate needle wood pulp, bleached sulfate broadleaf wood pulp and alkaline peroxide mechanical pulp, mixing them in a weight ratio of 65-70:5-12:15-30 to form a pulp mixture solution; S2: adding modified ground calcium carbonate and positive starch to the pulp mixture solution of step S1 and mixing them under the condition of a rotating speed of 600-800 r / min to obtain a base paper pulp; the base paper pulp comprises the pulp mixture solution 70-80%, the modified ground calcium carbonate 12-30% and the positive starch 0.6-1.0% by weight; the wire speed is 1200-1300 m / min; the modified ground calcium carbonate comprises the following raw materials in parts by weight: ground calcium carbonate 50-60 parts, fatty acid polyvinyl alcohol 2-4 parts, silane coupling agent 2-4 parts, calcium stearate 0.5-1.6 parts and water 280-320 parts; the preparation process of the modified ground calcium carbonate is as follows: the silane coupling agent and the fatty acid polyvinyl alcohol are added to water and stirred at a rotating speed of 500-600 r / min for 4-5 min, then the ground calcium carbonate and the calcium stearate are added and stirred at a rotating speed of 800-1000 r / min for 5-6 min, thereby obtaining the modified ground calcium carbonate; S3: producing base paper with the base paper pulp obtained in step S2, and the basis weight of the produced base paper is 160~180 g / m 2 wherein the moisture content is 4~8%; S4: starch glue liquid is used to coat the surface of the base paper by film transfer double-sided sizing process, the low shear viscosity is 10-14 cps, the total sizing amount is 2-3 g / m 2 , to obtain a surface sizing base paper; the starch glue liquid comprises the following raw materials in parts by weight: starch 70-80 parts, polyacrylamide 15-20 parts, polyvinyl alcohol 8-12 parts, water-soluble cellulose ether 8-12 parts, sodium hexametaphosphate 4-7 parts, and water 800-900 parts; S5: the surface-sized base paper is once bottom coated by film transfer double-sided coating to obtain once bottom coated paper; the film transfer coating amount is 10~20g / m 2 , the bottom coating metering bar pressure: upper roller / lower roller is 1.4~1.8 / 1.4~1.8bar; S6: the first base-coated paper is second base-coated by film transfer double-side coating, to obtain second base-coated paper; the film transfer coating amount is 8~18g / m 2 ; the base-coating metering bar pressure: upper roll / lower roll is 1.4~1.8 / 1.4~1.8bar; S7: the second base-coated paper is twice blade-coated, each time coating one side, to perform mid-coating; to obtain mid-coated paper; the mid-coating blade pressure is 35~60%, the total mid-coating coating amount is 18~24g / m 2 ; S8: twice blade coating is performed on the middle coated paper, one side each time, surface coating is performed, to obtain surface coated paper; surface coating blade pressure is 30~55%, total surface coating coating amount is 16~22g / m 2 ; S9: using a super calender to calender and modify the surface of the base paper of the digital paper to form a digital paper base paper; the super calender adopts the 4th and 9th compression zones and is used for calendering at a calendering temperature of 40-60 ℃ and a linear pressure of 70-90 kN / m; S10: coating the digital paper base paper with a treatment liquid to obtain a high-performance digital paper; the coating amount of the treatment liquid is 0.3-5 g, and the solid content of the treatment liquid is 20-40%; the treatment liquid comprises the following components in parts by weight: propionic acid 60-80 parts, diethylene glycol butyl ether 20-30 parts, phosphoric acid 10-20 parts, benzotriazole 1-5 parts and ethanol 0.1-1 part.

2. The high performance digital paper manufacturing method according to claim 1, characterized in that, In the step S4, the starch is one or both of corn starch and cassava starch.

3. The high performance digital paper manufacturing method according to claim 1, wherein, In the step S4, the preparation process of the starch glue solution is as follows: the starch and water with a total amount of 20-30% are stirred and uniformly mixed at a rotating speed of 600-800 r / min, then the polyvinyl alcohol is added and stirred and uniformly mixed at a rotating speed of 600-800 r / min, the temperature is raised to 90-95 ℃ and reacted for 15-20 min, the temperature is lowered to 35-40 ℃, the remaining water is mixed uniformly at a rotating speed of 600-800 r / min, then the sodium hexametaphosphate, the water-soluble cellulose ether and the polyacrylamide are sequentially added and stirred and uniformly mixed, thereby obtaining the starch glue solution.

4. The high performance digital paper manufacturing method according to claim 1, wherein, The coating of the first base coating and the second base coating in steps S5 and S6 comprises the following raw materials by weight: 20-28 parts of ground calcium carbonate C60 grade, 36-42 parts of ground calcium carbonate C65 grade, 1-3 parts of silane coupling agent, 8-10 parts of hydroxypropyl starch, 12-15 parts of vinyl acetate-ethylene copolymer latex, 0.5-1.0 parts of polydimethylsiloxane, 0.10-0.16 parts of sodium polyacrylate, 0.05-0.08 parts of tert-butyl alcohol, and 50-60 parts of water; the ground calcium carbonate C60 grade has a particle size of less than 2 um and a particle content of 60-62%; and the ground calcium carbonate C65 grade has a particle size of less than 2 um and a particle content of 64-66%.

5. The high performance digital paper manufacturing method according to claim 1, wherein, The coating of the intermediate coating in step S7 comprises the following raw materials by weight: 40-46 parts of ground calcium carbonate C60 grade, 36-40 parts of ground calcium carbonate C65 grade, 2-4 parts of silane coupling agent, 8-10 parts of hydroxypropyl starch, 9-11 parts of biological latex, 1-1.5 parts of polydimethylsiloxane, 0.08-0.15 parts of sodium polyacrylate, 0.05-0.08 parts of tert-butyl alcohol, and 50-70 parts of water; the ground calcium carbonate C60 grade has a particle size of less than 2 um and a particle content of 60-62%; and the ground calcium carbonate C65 grade has a particle size of less than 2 um and a particle content of 64-66%.

6. The high performance digital paper manufacturing method according to claim 1, wherein, The coating of the top coating in step S8 comprises the following raw materials by weight: 40-46 parts of ground calcium carbonate C65 grade, 30-38 parts of ground calcium carbonate C98 grade, 3-5 parts of silane coupling agent, 10-15 parts of hydroxypropyl starch, 8-11 parts of vinyl acetate-ethylene copolymer latex, 0.5-1.2 parts of polydimethylsiloxane, 0.08-0.15 parts of sodium polyacrylate, 0.05-0.08 parts of tert-butyl alcohol, and 40-60 parts of water; the ground calcium carbonate C65 grade has a particle size of less than 2 um and a particle content of 64-66%; and the ground calcium carbonate C98 grade has a particle size of less than 2 um and a particle content of 98-100%.

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