Low-damping high-strength corrugated medium and method for producing the same

Abstract

The application belongs to the technical field of papermaking, and particularly relates to low-attenuation high-strength corrugated paper and a production method thereof. The method comprises the following technological process: raw materials are conveyed by a chain plate, and then are subjected to D-type hydraulic pulper, high-concentration sand remover, coarse screen, low-concentration sand remover, fine screen, multi-disc thickener, storage tank, double-disc pulper, pulp tank, pre-bleaching tank, white water tank, flushing pump, pre-screen, headbox, net part, pressing part, pre-drying part, sizing machine, post-drying part, winding part, rewinding and packaging and warehousing. The paper machine is a long-net multi-cylinder corrugated paper machine. The proportion of the raw materials is as follows: 85-90 wt.% of waste cartons and 15-10 wt.% of mineral fibers. Surface glue, i.e. edible corn starch, acrylate and glyoxal, is added to the sizing machine. In the application, mineral fibers are added to replace part of the fibers. The mineral fibers are not easy to absorb moisture, can block the moisture from entering the inside of the fibers, and can improve the ring crush strength of the paper. Sodium silicate also has the effect of improving the ring crush strength of the paper.

Description

Technical Field

[0001] This invention belongs to the field of papermaking technology, specifically relating to low-attenuation high-strength corrugated base paper and its production method. Background Technology

[0002] High-strength corrugated base paper, as the core material of packaging cartons, directly determines the compressive strength and overall stability of the cartons. In the packaging industry, the compressive strength of cartons is a crucial indicator of their quality, especially during logistics transportation and warehousing, where cartons need to withstand various external forces such as stacking, compression, and vibration. Therefore, the ring crush strength (CCT, Concora Crush Test) of high-strength corrugated base paper is one of the key factors affecting the compressive strength of cartons.

[0003] However, high-strength corrugated base paper faces a significant technical challenge in practical applications: in high-temperature and high-humidity environments, especially during the rainy summer season when ambient air humidity typically reaches 70-90%, the paper easily absorbs moisture. After absorbing moisture, the internal fiber structure of the paper expands, weakening the bonding force between fibers and leading to a significant decrease in ring crush strength. Studies have shown that in high-humidity environments, the ring crush strength of high-strength corrugated base paper can decrease by 30-40%, severely affecting the compression resistance of cartons. This decrease not only causes cartons to collapse during transportation and stacking but can also damage the goods inside, resulting in substantial economic losses for businesses.

[0004] The ring crush strength degradation of existing high-strength corrugated base paper under high humidity environments has become a technical bottleneck restricting the improvement of packaging carton performance. Therefore, developing a low-degradation, high-strength corrugated base paper has significant practical importance and application value. Summary of the Invention

[0005] In view of the shortcomings of the prior art, the purpose of this invention is to provide a low-attenuation, high-strength corrugated base paper with good ring crush strength.

[0006] The present invention also provides a preparation method that is simple, easy to implement, and suitable for large-scale production.

[0007] The production method of low-attenuation high-strength corrugated base paper according to the present invention includes the following process flow:

[0008] Raw materials → Chain conveyor → D-type hydraulic pulper → High-consistency desander → Coarse screen → Low-consistency desander → Fine screen → Multi-disc thickener → Storage tank → Double-disc refiner → Pulp tank → Pre-pulping tank → External white water tank → Pulp pump → Pre-screen → Headbox → Wire section → Press section → Pre-drying section → Sizing machine → Post-drying section → Winding section → Rewinding → Packaging and warehousing;

[0009] The paper machine used is a long-wire multi-cylinder corrugated paper machine;

[0010] The raw material composition is as follows: 85-90 wt.% waste cardboard boxes, 15-10 wt.% mineral fibers;

[0011] The surface adhesive added to the sizing machine is: 45-55 kg / ton of edible corn starch, 2.25-2.75 kg / ton of acrylate, and 1.5-2.5 kg / ton of glyoxal.

[0012] The preparation method of the surface adhesive is as follows:

[0013] Add 500±10kg of water to the starch dissolving tank, start the stirrer, slowly add 100±5kg of edible corn starch and 5±0.5kg of acrylate, stir evenly, transfer to the starch cooking tank, start the stirrer, pass steam to heat to 95-98℃, close the steam valve, keep warm for 25-30min, then transfer to the starch dilution tank, add 55-60℃ warm water, dilute to a concentration of 9.5-10%, viscosity of 30-80mPa·s, and temperature of 65-70℃, to obtain the surface adhesive, transfer to the surface adhesive storage tank for later use.

[0014] The sizing process of the sizing machine is as follows: the surface adhesive is lifted from the surface adhesive storage tank to the feeding tank of the sizing machine, and 1.5-2.5 kg / ton of glyoxal is added to the feeding tank using a metering pump. The material is then lifted to the surface sizing machine to apply surface adhesive to the corrugated base paper.

[0015] Glyoxal can improve the waterproof and moisture-proof properties and tensile strength of paper, while also increasing the paper's wrinkle resistance; acrylates can improve the wrinkle resistance and waterproof properties of paper.

[0016] In the aforementioned double-disc refiner process, three DD1200mm double-disc refiners are used in series for refining. The refining discs are of different power ratings: 600kW, 500kW, and 500kW. The valve opening is 70-75%, the pulp concentration is 4.5-5.0%, the pulp freeness is 33-36°SR, and the wet weight is 3-4g.

[0017] The pulping tank contains 7-10 kg / ton of sodium silicate with a solid content of 34-36%, 5-10 kg / ton of PAE wet strength agent with a solid content of 37-39%, and 200-300 g / ton of organic bromine bactericide with a solid content of 9-11%.

[0018] The pre-paper washing pool contains 5-8 kg / ton of ASA with a solid content of 39-41%.

[0019] The inlet of the screen is filled with 300-500g / ton of polyethyleneimine with a solid content of 19-21%.

[0020] Add 100-300g of defoamer with a solid content of 9-11% to the white water tank outside the paper machine.

[0021] The paper machine is a 4400 type long-wire multi-cylinder corrugated paper machine. The operating parameters are: basis weight 135-145g, wire density 1.0-1.2%, headbox lip opening 12-14mm, wire speed ratio 0.94-0.96, and dryness of the roll exiting the press section 21-23%; dryness of the press section exiting the press section 48-52%, and linear pressure of the press section's main roll 280-300KN / m. The sizing machine has a linear pressure of 100-120KN / m, a dryness of 93-95% entering the sizing machine, a dryness of 65-68% exiting the sizing machine, and a paper dryness of 93-95%.

[0022] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0023] 1. In this invention, mineral fibers are added to replace part of the fiber. The mineral fibers do not easily absorb moisture and can prevent water from penetrating into the fiber interior. At the same time, the mineral fibers can improve the ring crush strength of the paper. Sodium silicate also has the effect of improving the ring crush strength of the paper.

[0024] 2. Adding ASA sizing agent to the pulp during sizing accelerates curing after printing and reduces the rate of ring crush strength decay in the finished paper.

[0025] 3. The addition of glyoxal and acrylate to the surface sizing enhances the paper's internal water resistance, improves the film-forming properties of the paper surface, reduces the intrusion of external moisture, and ensures the stability of the paper's ring crush strength. Detailed Implementation

[0026] The present invention will be further described below with reference to the embodiments.

[0027] Unless otherwise specified, all raw materials used in the examples were commercially available.

[0028] Mineral fiber, basalt-type mineral fiber, Xiamen Sulu Mineral Fiber Materials Co., Ltd.;

[0029] Basalt mineral fiber index:

[0030] (1) Length, typical maximum fiber length is 6mm;

[0031] (2) Diameter, average diameter 5μm;

[0032] (3) Sieving: 95% pass through a 250μm sieve and 65% pass through a 63μm sieve;

[0033] (4) Melting point, 1500℃;

[0034] (5) Tensile strength, ≥2500MPa;

[0035] (6) Elastic modulus, ≥90Gpa.

[0036] Sodium silicate, solid content 35±1%, Zibo Guanxin New Materials Factory;

[0037] Organic bromine bactericide, solid content 10±1%, model WL-20, Zhejiang Chuanhua Chemical Co., Ltd.

[0038] PAE wet strength agent, solid content 38±1%, Tianfang Shenghong Chemical Co., Ltd.

[0039] ASA, solids content 40±1%, Kemira Chemical Co., Ltd.

[0040] Polyethyleneimine, solid content 20±1%, Zhejiang Chuanhua Chemical Co., Ltd.

[0041] Defoamer DF9500, solid content 10±1%, Nantian Agricultural Science and Chemical Co., Ltd.;

[0042] Glyoxal, solid content 30±1%, Hubei Guangao Biotechnology Co., Ltd.;

[0043] Acrylic ester, model TK1109, Shanghai Kaiyin Chemical Co., Ltd.

[0044] Example 1

[0045] The production method of the low-attenuation high-strength corrugated base paper includes the following process flow:

[0046] Raw materials → Chain conveyor → D-type hydraulic pulper → High-consistency desander → Coarse screen → Low-consistency desander → Fine screen → Multi-disc thickener → Storage tank → Double-disc refiner → Pulp tank → Pre-pulping tank → External white water tank → Pulp pump → Pre-screen → Headbox → Wire section → Press section → Pre-drying section → Sizing machine → Post-drying section → Winding section → Rewinding → Packaging and warehousing;

[0047] The paper machine used is a long-wire multi-cylinder corrugated paper machine;

[0048] The raw material composition is as follows: 85 wt.% waste cardboard boxes, 15 wt.% mineral fibers;

[0049] The surface adhesive added to the sizing machine is: 45 kg / ton of edible corn starch, 2.25 kg / ton of acrylate, and 1.5 kg / ton of glyoxal.

[0050] The preparation method of the surface adhesive is as follows:

[0051] Add 490 kg of water to the starch dissolving tank, start the stirrer, slowly add 95 kg of edible corn starch and 4.5 kg of acrylate, stir evenly, transfer to the starch cooking tank, start the stirrer, pass steam to heat to 95℃, close the steam valve, keep warm for 25 minutes, then transfer to the starch dilution tank, add 55℃ warm water, dilute to a concentration of 9.5%, viscosity of 30 mPa·s, and temperature of 65℃, to obtain the surface adhesive, transfer to the surface adhesive storage tank for later use.

[0052] The sizing process of the sizing machine is as follows: the surface adhesive is lifted from the surface adhesive storage tank to the feeding tank of the sizing machine, and 1.5 kg of glyoxal per ton of paper is added to the feeding tank using a metering pump. The sizing machine is then used to apply the surface adhesive to the corrugated base paper.

[0053] In the aforementioned concentrated multi-disc refiner process, three DD1200mm disc refiners are used in series for refining. The three refiners have power ratings of 600kW, 500kW, and 500kW, respectively. The valve opening is 70%, the pulp concentration is 4.5%, the pulp freeness is 33°SR, and the wet weight is 3g.

[0054] The pulping tank contains 7 kg of sodium silicate per ton of paper, 5 kg of PAE wet strength agent per ton of paper, and 200 g of organic bromine bactericide per ton of paper.

[0055] Add 5 kg / ton of ASA to the pre-paper washing pool.

[0056] 300g / ton of polyethyleneimine is added to the inlet of the screen.

[0057] Add 100g of defoamer per ton of paper to the white water tank outside the paper machine.

[0058] The paper machine is a 4400 type long-wire multi-cylinder corrugated paper machine. The operating parameters are: wire density 1.0%, lip opening 12mm, wire speed ratio 0.94, and dryness of the exit roll 21%; dryness of the exit press section 48%; and linear pressure of the press section's main roll 280KN / m. The sizing machine has a sizing roll linear pressure of 100KN / m, an entry dryness of 93% from the sizing machine, an exit dryness of 65% from the sizing machine, and a finished paper dryness of 93%.

[0059] Example 2

[0060] The production method of the low-attenuation high-strength corrugated base paper includes the following process flow:

[0061] Raw materials → Chain conveyor → D-type hydraulic pulper → High-consistency desander → Coarse screen → Low-consistency desander → Fine screen → Multi-disc thickener → Storage tank → Double-disc refiner → Pulp tank → Pre-pulping tank → External white water tank → Pulp pump → Pre-screen → Headbox → Wire section → Press section → Pre-drying section → Sizing machine → Post-drying section → Winding section → Rewinding → Packaging and warehousing;

[0062] The paper machine used is a long-wire multi-cylinder corrugated paper machine;

[0063] The raw material composition is as follows: 90 wt.% waste cardboard boxes, 10 wt.% mineral fibers;

[0064] The surface adhesive added to the sizing machine is: 55 kg / ton of edible corn starch, 2.75 kg / ton of acrylate, and 2.5 kg / ton of glyoxal.

[0065] The preparation method of the surface adhesive is as follows:

[0066] Add 510 kg of water to the starch dissolving tank, start the stirrer, slowly add 105 kg of edible corn starch and 5.5 kg of acrylate, stir evenly, transfer to the starch cooking tank, start the stirrer, pass steam to heat to 98℃, close the steam valve, keep warm for 30 minutes, then transfer to the starch dilution tank, add 60℃ warm water, dilute to a concentration of 10%, viscosity of 80 mPa·s, and temperature of 70℃, to obtain the surface adhesive, transfer to the surface adhesive storage tank for later use.

[0067] The sizing process of the sizing machine is as follows: the surface adhesive is lifted from the surface adhesive storage tank to the feeding tank of the sizing machine, and 2.5 kg / ton of glyoxal is added to the feeding tank using a metering pump. The sizing machine is then used to apply the surface adhesive to the corrugated base paper.

[0068] In the aforementioned double-disc refiner process, three DD1200mm double-disc refiners are used in series for refining. The refining discs are of different types. The power of the three double-disc refiners is 600kW, 500kW, and 500kW respectively. The valve opening is 75%, the pulp concentration is 5.0%, the pulp freeness is 36°SR, and the wet weight is 4g.

[0069] Sodium silicate 10 kg / ton of paper, PAE wet strength agent 10 kg / ton of paper, and organic bromine bactericide 300 g / ton of paper are added to the pulping tank.

[0070] Add 8 kg / ton of ASA to the pre-paper washing pool.

[0071] Add 500g / ton of polyethyleneimine to the inlet of the screen.

[0072] Add 300g of defoamer per ton of paper to the white water tank outside the paper machine.

[0073] The paper machine is a 4400 type long-wire multi-cylinder corrugated paper machine. The operating parameters are: wire density 1.2%, lip opening 14mm, wire speed ratio 0.96, and dryness of the exit roll 23%; dryness of the exit press section 52%; and linear pressure of the press section's main roll 300KN / m. The sizing machine has a sizing roll linear pressure of 120KN / m, an entry dryness of 95% from the sizing machine, an exit dryness of 68% from the sizing machine, and a finished paper dryness of 95%.

[0074] Example 3

[0075] The production method of the low-attenuation high-strength corrugated base paper includes the following process flow:

[0076] Raw materials → Chain conveyor → D-type hydraulic pulper → High-consistency desander → Coarse screen → Low-consistency desander → Fine screen → Multi-disc thickener → Storage tank → Double-disc refiner → Pulp tank → Pre-pulping tank → External white water tank → Pulp pump → Pre-screen → Headbox → Wire section → Press section → Pre-drying section → Sizing machine → Post-drying section → Winding section → Rewinding → Packaging and warehousing;

[0077] The paper machine used is a long-wire multi-cylinder corrugated paper machine;

[0078] The raw material composition is as follows: 87 wt.% waste cardboard boxes, 13 wt.% mineral fibers;

[0079] The surface adhesive added to the sizing machine is: 50 kg / ton of edible corn starch, 2.5 kg / ton of acrylate, and 2 kg / ton of glyoxal.

[0080] The preparation method of the surface adhesive is as follows:

[0081] Add 500 kg of water to the starch dissolving tank, start the stirrer, slowly add 100 kg of edible corn starch and 5 kg of acrylate, stir evenly, transfer to the starch cooking tank, start the stirrer, pass steam to heat to 96℃, close the steam valve, keep warm for 28 minutes, then transfer to the starch dilution tank, add 58℃ warm water, dilute to a concentration of 9.8%, viscosity of 50 mPa·s, and temperature of 68℃, to obtain the surface adhesive, transfer to the surface adhesive storage tank for later use.

[0082] The sizing process of the sizing machine is as follows: the surface adhesive is lifted from the surface adhesive storage tank to the feeding tank of the sizing machine, and 2 kg of glyoxal per ton of paper is added to the feeding tank using a metering pump. The sizing machine is then used to apply the surface adhesive to the corrugated base paper.

[0083] In the aforementioned double-disc refiner process, three DD1200mm double-disc refiners are used in series for refining. The refining discs are of different types. The power of the three double-disc refiners is 600kW, 500kW, and 500kW respectively. The valve opening is 72%, the pulp concentration is 4.8%, the pulp freeness is 34°SR, and the wet weight is 3.5g.

[0084] The pulping tank contains 8 kg of sodium silicate per ton of paper, 8 kg of PAE wet strength agent per ton of paper, and 250 g of organic bromine bactericide per ton of paper.

[0085] 7 kg / ton of ASA was added to the pre-paper washing tank.

[0086] 400g / ton of polyethyleneimine is added to the inlet of the screen.

[0087] Add 200g of defoamer per ton of paper to the white water tank outside the paper machine.

[0088] The paper machine is a 4400 type long-wire multi-cylinder corrugated paper machine. The operating parameters are: wire density 1.1%, lip opening 13mm, wire speed ratio 0.95, and dryness of the exit roll 22%; dryness of the exit press section 50%; and linear pressure of the press section's main roll 290KN / m. The sizing machine has a sizing roll linear pressure of 110KN / m, an entry dryness of 94% from the sizing machine, an exit dryness of 67% from the sizing machine, and a finished paper dryness of 94%.

[0089] Comparative Example 1: The 87% waste cardboard box + 13% mineral fiber was replaced with 100% waste paper pulp, and other production process conditions were the same as in Example 3;

[0090] Comparative Example 2: Sodium silicate was removed, and other production process conditions were the same as in Example 3;

[0091] Comparative Example 3: Glyoxal was removed, and other production process conditions were the same as in Example 3;

[0092] Comparative Example 4: The acrylate was removed, and other production process conditions were the same as in Example 3;

[0093] Comparative Example 5: ASA was replaced with alkyl ketene dimer (AKD), and other production process conditions were the same as in Example 3.

[0094] The resulting paper was tested for basis weight: GB / T 451.2, water absorption: GB / T 1540, ring crush strength: GB / T2679.8, and moisture content: GB / T 462.

[0095] The following data represents the test results of the paper sheets upon removal from the machine:

[0096] Table 1. Paper off-machine test results

[0097]

[0098] The following data are the results of the paper sheets being left to stand in the laboratory for 48 hours:

[0099] Table 2. Test results after the paper was left to stand for 48 hours.

[0100]

[0101]

[0102] The comparison data above shows that:

[0103] (1) If mineral fiber, sodium silicate, acrylate, glyoxal, and ASA are replaced with AKD, the ring crush strength will not meet the requirements of the paper; if glyoxal and ASA are not used and replaced with AKD, the water absorption and dripping time of the paper will not meet the requirements.

[0104] (2) By comparing the data of different time periods of paper placement, the ring crush strength decreased when mineral fiber, sodium silicate, acrylate, glyoxal, and ASA were replaced with AKD. However, when the time was long enough, the decrease in ring crush tended to reach equilibrium.

Claims

1. A method for producing low-attenuation, high-strength corrugated base paper, characterized in that, The process includes the following steps: Raw materials → Chain conveyor → D-type hydraulic pulper → High-consistency desander → Coarse screen → Low-consistency desander → Fine screen → Multi-disc thickener → Storage tank → Double-disc refiner → Pulp tank → Pre-pulping tank → External white water tank → Pulp pump → Pre-screen → Headbox → Wire section → Press section → Pre-drying section → Sizing machine → Post-drying section → Winding section → Rewinding → Packaging and warehousing; The paper machine used is a long-wire multi-cylinder corrugated paper machine; The raw material composition is as follows: 85-90 wt.% waste cardboard boxes, 15-10 wt.% mineral fibers; The surface adhesive added to the sizing machine is: 45-55 kg / ton of edible corn starch, 2.25-2.75 kg / ton of acrylate, and 1.5-2.5 kg / ton of glyoxal. The preparation method of the surface adhesive is as follows: Add water to the starch dissolving tank, turn on the stirrer, add edible corn starch and acrylate, stir evenly, transfer to the starch cooking tank, turn on the stirrer, pass steam to heat to 95-98℃, close the steam valve, keep warm for 25-30 minutes, then transfer to the starch dilution tank, add 55-60℃ warm water, dilute to a concentration of 9.5-10%, viscosity of 30-80 mPa·s, and temperature of 65-70℃, to obtain the surface adhesive, transfer to the surface adhesive storage tank for later use; The sizing process of the sizing machine is as follows: the surface adhesive is lifted from the surface adhesive storage tank to the feeding tank of the sizing machine, and 1.5-2.5 kg / ton of glyoxal is added to the feeding tank using a metering pump. The surface adhesive is then lifted to the surface sizing machine to apply sizing to the corrugated base paper. Add 5-8 kg / ton of ASA to the pre-paper washing pool.

2. The method for producing low-attenuation, high-strength corrugated base paper according to claim 1, characterized in that, In the aforementioned double-disc refiner process, three DD1200mm double-disc refiners are used in series for refining. The refining discs are of different power ratings: 600kW, 500kW, and 500kW. The valve opening is 70-75%, the pulp concentration is 4.5-5.0%, the pulp freeness is 33-36°SR, and the wet weight is 3-4g.

3. The method for producing low-attenuation, high-strength corrugated base paper according to claim 1, characterized in that, The pulping tank contains 7-10 kg / ton of sodium silicate, 5-10 kg / ton of PAE wet strength agent, and 200-300 g / ton of organic bromine bactericide.

4. The method for producing low-attenuation, high-strength corrugated base paper according to claim 1, characterized in that, 300-500g / ton of paper is added to the inlet of the screen.

5. The method for producing low-attenuation, high-strength corrugated base paper according to claim 1, characterized in that, Add 100-300g of defoamer per ton of paper to the external white water tank.

6. The method for producing low-attenuation, high-strength corrugated base paper according to claim 1, characterized in that, The paper machine is a 4400 type long-wire multi-cylinder corrugated paper machine. The operating parameters of the paper machine are as follows: basis weight 135-145g, wire density 1.0-1.2%, headbox lip opening 12-14mm, wire speed ratio 0.94-0.96, dryness of the roll exit 21-23%; dryness of the press exit 48-52%; linear pressure of the press roll 280-300KN / m; linear pressure of the sizing roll 100-120KN / m; dryness of the sizing machine feed 93-95%; dryness of the sizing machine output 65-68%; and dryness of the finished paper 93-95%.

7. A low-attenuation, high-strength corrugated base paper, characterized in that, It is produced by any one of the production methods described in claims 1-6.

Images