Broken-corrugation-free high-strength corrugating base paper and production method thereof

Abstract

The invention relates to the technical field of papermaking, in particular to broken-corrugation-free high-strength corrugating base paper and a production method thereof. Comprising the following technological processes. Waste paper box-> chain plate conveying-> D-type hydrapulper-> discharging pool-> high-concentration desander-> first-section coarse screen-> first-section low-concentration desander-> first-section fine screen-> concentration multi-disc pulping machine-> concentration after pool-> pulp forming pool-> machine front pool-> machine external white water tank-> slushing pump-> pressurized screen-> headbox-> net part-> pressing part-> front drying part-> sizing machine-> after-drying drying, coiling, rewinding, packaging and warehousing; adding nano cellulose into the pulp forming tank; surface glue is added into the sizing machine, wherein 20-25 kg of edible corn starch, 2-4 kg of CMC and 1-3 kg of sizing enhancer are added into each ton of paper. The nano cellulose and the dry strength agent are added into the pulp, so that the tensile strength and the folding strength of the corrugated paper can be improved, and the CMC is added, so that the folding strength of the corrugated paper can be improved.

Description

Technical Field

[0001] The invention relates to the technical field of papermaking, and in particular to high-strength corrugated paper without fluting and a production method thereof. Background Art

[0002] Corrugated paper, also known as corrugated core paper, is the key material for the core layer of packaging carton paperboard. It is mainly used to support the structure of the carton and bear the main load-bearing function. In the production process of packaging cartons, the first thing to do is to make cardboard. This process usually includes the middle layer of corrugated paper passing through the corrugated roller for fluting, and then bonding it with the upper and lower layers of boxboard paper by glue, and then drying to form cardboard. The cardboard is then cut into specified sizes for making cartons.

[0003] However, in winter, due to the dry climate and low air humidity, the corrugated base paper is prone to "broken flutes" during the cardboard manufacturing process. Specifically, during the corrugation process, the top of the flutes of the corrugated base paper cracks. This cracking not only affects the appearance quality of the cardboard, but more importantly, it causes a significant decrease in the compressive strength of the manufactured carton. When the packaged goods are stacked, the insufficient compressive strength of the carton will lead to a box collapse accident, causing serious economic losses.

[0004] In the prior art, the production process and material ratio of corrugated paper usually fail to fully consider the performance requirements under extreme climatic conditions. Especially in low humidity environments, the folding resistance and cracking resistance of corrugated paper are insufficient, resulting in frequent broken flutes. This not only affects the overall quality of the carton, but also increases production costs and scrap rates. Therefore, developing a high-strength corrugated paper to improve its folding resistance and cracking resistance has become the key to solving the above problems. Summary of the invention

[0005] In view of the deficiencies in the prior art, the purpose of the present invention is to provide a high-strength corrugated paper without broken flutes, which can still maintain good folding resistance and crack resistance in a low humidity environment, effectively solve the problem of broken flutes in the cardboard manufacturing process, thereby improving the compressive strength of the carton and meeting customers' demand for high-quality packaging cartons.

[0006] The present invention also provides a preparation method thereof. Through the implementation of the present invention, box collapse accidents caused by broken edges can be significantly reduced, economic losses can be reduced, and the market competitiveness of packaging cartons can be improved.

[0007] The method for producing high-strength corrugated paper without broken flutes of the present invention comprises the following process flow:

[0008] Waste paper box → chain conveyor → D-type hydraulic pulper → unloading tank → high-concentration desander → coarse screen → low-concentration desander → fine screen → multi-disc thickener → post-concentration tank → double-disc refiner → pulping tank → pre-slurry tank → external white water tank → pulping pump → pressure screen → headbox → wire section → pressing section → front drying section → sizing machine → post-drying section → winding section → rewinding → packaging and storage;

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

[0010] Adding nanocellulose into a pulping tank;

[0011] The waste paper box is a LOCC waste paper box, and the mass ratio of the LOCC waste paper box to the nanocellulose is (90-95%):(10-5%);

[0012] The surface glue is added into the sizing machine: edible corn starch 20-25kg / ton of paper, CMC: 2-4kg / ton of paper, and sizing enhancer: 1-3kg / ton of paper.

[0013] The preparation process of the surface adhesive is as follows:

[0014] Add water to edible corn starch, CMC and sizing enhancer to dissolve in the surface glue preparation tank, then transfer to the surface glue cooking tank, stir evenly, pass steam, and heat to 93-97°C, keep warm for 18-22 minutes, transfer to the surface glue dilution tank, mix with water to form surface glue, prepare a surface glue solution with a concentration of 5-7% and a viscosity of 25-50mPa·s, and transfer to the surface glue storage tank for standby use.

[0015] The sizing process of the sizing machine is as follows: the surface glue solution is lifted from the surface glue storage tank to the feeding tank, and the feeding tank is lifted to the surface sizing machine to apply surface glue to the corrugated base paper. Figure 1 shown.

[0016] In the double-disc refiner process, two DD1200mm double-disc refiners are used in series for refining, with debonding type refiners, and the power of the two double-disc refiners is (450-500) kW and (450-500) kW respectively.

[0017] In the double-disc refiner process, the valve opening is 70-75%, the pulping concentration is 4.5-5.0%, the pulping degree is 33-36°SR, and the wet weight is 3-4g.

[0018] Dry strength agents are added into the pulping tank: 10-15 kg / ton of paper of amphoteric polyacrylamide and 100-200 g / ton of paper of organic bromine fungicide.

[0019] 200-300g / ton of paper of defoaming agent is added into the white water tank outside the machine.

[0020] The operating parameters of the paper machine are: headbox lip opening 12-14 mm, web concentration 1.0-1.2%, web speed ratio 0.94-0.96, machine speed 580-600 m / min, drying cylinder steam pressure 530-550 kPa for front drying and 480-500 kPa for rear drying.

[0021] The finished paper weight is 126-134g, and the finished paper moisture content is 8-10%.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] (1) The present invention adds nanocellulose and dry strength agent into the pulp, which can improve the tensile strength and folding endurance of corrugated paper.

[0024] (2) The present invention can improve the folding resistance of corrugated paper by adding CMC to the surface sizing.

[0025] (3) The present invention reduces the amount of edible corn starch used in surface sizing. In the normal process, the amount of edible corn starch used is 30-40 kg / ton of paper. The present invention reduces the amount of edible corn starch used to 20-25 kg / ton of paper to reduce the brittleness of corrugated paper.

[0026] (4) The present invention reduces the amount of sizing enhancer in the surface sizing formula. The normal process uses 4-6 kg / ton of paper. The present invention reduces the amount of sizing enhancer to 1-3 kg / ton of paper to reduce the brittleness of corrugated paper; at the same time, the water absorption is reduced from 20-30 g / m 2 Increase to 40-60g / m 2 , moderately increase the moisture absorption performance of corrugated paper and improve the flexibility of corrugated paper.

[0027] (5) The present invention increases the moisture content of the finished paper from 6-7% to 8-10%, thereby increasing the flexibility of the corrugated paper. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The accompanying drawings described herein are used to provide a further understanding of the present invention and constitute a part of the present invention. In the accompanying drawings:

[0029] Figure 1 This is a flow chart of the surface glue application of the present invention;

[0030] In the figure: 1. Surface glue preparation tank; 2. Surface glue cooking tank; 3. Surface glue dilution tank; 4. Surface glue storage tank; 5. Feeding tank; 6. Immersion glue applicator. DETAILED DESCRIPTION

[0031] The present invention will be further described below with reference to the embodiments.

[0032] Unless otherwise specified, all raw materials used in the examples are commercially available.

[0033] Nanocellulose, Jinan Shengquan Group Co., Ltd.; (solid content 10±1%, model NFC-33L2);

[0034] Amphoteric polyacrylamide, Hangzhou Halima Chemical Co., Ltd.; (solid content 20±1%, model HM-2900);

[0035] Organic bromine fungicide, Zhejiang Chuanhua Chemical Co., Ltd.; (solid content 10±1%, model WL-20,);

[0036] Polyether defoamer, Zhejiang Chuanhua Chemical Co., Ltd.; (solid content 20±1%, model DF9500);

[0037] Sizing enhancer, Jinzhou Dacheng Modified Starch Co., Ltd., model SY-GTJ6.

[0038] Example 1

[0039] The method for producing high-strength corrugated paper without broken flutes comprises the following process flow:

[0040] Waste paper box → chain conveyor → D-type hydraulic pulper → unloading tank → high-concentration desander → coarse screen → low-concentration desander → fine screen → multi-disc thickener → post-concentration tank → double-disc refiner → pulping tank → pre-slurry tank → external white water tank → pulping pump → pressure screen → headbox → wire section → pressing section → front drying section → sizing machine → post-drying section → winding section → rewinding → packaging and storage;

[0041] Adding nanocellulose into a pulping tank;

[0042] The waste paper box is a LOCC waste paper box, and the mass ratio of the LOCC waste paper box to the nanocellulose is 90%:10%;

[0043] The surface glue is added into the sizing machine: edible corn starch 20kg / ton paper, CMC: 2kg / ton paper, and sizing enhancer: 1kg / ton paper.

[0044] The preparation process of the surface adhesive is as follows:

[0045] Add water to edible corn starch, CMC and sizing enhancer to dissolve in the surface glue preparation tank, then transfer to the surface glue cooking tank, stir evenly, pass steam, and heat to 93°C, keep warm for 18 minutes, transfer to the surface glue dilution tank and mix with water to form surface glue, prepare a surface glue solution with a concentration of 5% and a viscosity of 25 mPa·s, and transfer to the surface glue storage tank for standby use.

[0046] The sizing process of the sizing machine is as follows: the surface glue solution is lifted from the surface glue storage tank to the feeding tank, and the feeding tank is lifted to the surface sizing machine to apply surface glue to the corrugated base paper. Figure 1 shown.

[0047] In the double-disc refiner process, two DD1200mm double-disc refiners are used in series for refining, with debonding type refiners, and the power of the two double-disc refiners is 450kW and 450kW respectively.

[0048] In the concentrated multi-disc refiner process, the valve opening is 70%, the pulping concentration is 4.5%, the pulping beating degree is 33°SR, and the wet weight is 3g.

[0049] Dry strength agents are added into the pulping tank: 10 kg / ton of paper of amphoteric polyacrylamide and 100 g / ton of paper of organic bromine fungicide.

[0050] 200g / ton of paper of defoaming agent is added into the white water tank outside the paper machine.

[0051] The operating parameters of the paper machine are: headbox lip opening 12 mm, web concentration 1.0%, web speed ratio 0.94, machine speed 580 m / min, drying cylinder steam pressure 530 kPa for front drying, 480 kPa for rear drying, and finished paper moisture 8%.

[0052] Example 2

[0053] The method for producing high-strength corrugated paper without broken flutes comprises the following process flow:

[0054] Waste paper box → chain conveyor → D-type hydraulic pulper → unloading tank → high-concentration desander → coarse screen → low-concentration desander → fine screen → multi-disc thickener → post-concentration tank → double-disc refiner → pulping tank → pre-slurry tank → external white water tank → pulping pump → pressure screen → headbox → wire section → pressing section → front drying section → sizing machine → post-drying section → winding section → rewinding → packaging and storage;

[0055] Adding nanocellulose into a pulping tank;

[0056] The waste paper box is a LOCC waste paper box, and the mass ratio of the LOCC waste paper box to the nanocellulose is 95%:5%;

[0057] The surface glue is added into the sizing machine: 25kg / ton of paper of edible corn starch, 4kg / ton of paper of CMC, and 3kg / ton of paper of sizing intensifier.

[0058] The preparation process of the surface adhesive is as follows:

[0059] Add water to edible corn starch, CMC and sizing enhancer to dissolve in the surface glue preparation tank, then transfer to the surface glue cooking tank, stir evenly, pass steam, and heat to 97°C, keep warm for 22 minutes, transfer to the surface glue dilution tank and mix with water to form surface glue, prepare a surface glue solution with a concentration of 7% and a viscosity of 50mPa·s, and transfer to the surface glue storage tank for standby use.

[0060] The sizing process of the sizing machine is as follows: the surface glue solution is lifted from the surface glue storage tank to the feeding tank, and the feeding tank is lifted to the surface sizing machine to apply surface glue to the corrugated base paper. Figure 1 shown.

[0061] In the double-disc refiner process, two DD1200mm double-disc refiners are used in series for refining, with debonding type refiners, and the powers of the two double-disc refiners are 500kW and 500kW respectively.

[0062] In the double-disc refiner process, the valve opening is 75%, the pulping concentration is 5.0%, the pulping degree is 36°SR, and the wet weight is 4g.

[0063] Dry strength agents are added into the pulping tank: 15 kg / ton of paper of amphoteric polyacrylamide and 200 g / ton of paper of organic bromine fungicide.

[0064] 300g / ton of paper of defoaming agent is added into the white water tank outside the paper machine.

[0065] The paper machine operation parameters are: headbox lip opening 14mm, web concentration 1.2%, web speed ratio 0.96, machine speed 600m / min, drying cylinder steam pressure 550kPa for front drying and 500kPa for rear drying, and finished paper moisture 10%.

[0066] Example 3

[0067] The method for producing high-strength corrugated paper without broken flutes comprises the following process flow:

[0068] Waste paper box → chain conveyor → D-type hydraulic pulper → unloading tank → high-concentration desander → coarse screen → low-concentration desander → fine screen → multi-disc thickener → post-concentration tank → double-disc refiner → pulping tank → pre-slurry tank → external white water tank → pulping pump → pressure screen → headbox → wire section → pressing section → front drying section → sizing machine → post-drying section → winding section → rewinding → packaging and storage;

[0069] Adding nanocellulose into a pulping tank;

[0070] The waste paper box is a LOCC waste paper box, and the mass ratio of the LOCC waste paper box to the nanocellulose is 93%:7%;

[0071] The surface glue is added into the sizing machine: edible corn starch 22kg / ton paper, CMC: 3kg / ton paper, sizing enhancer: 2kg / ton paper.

[0072] The preparation process of the surface adhesive is as follows:

[0073] Add water to edible corn starch, CMC and sizing enhancer to dissolve in the surface glue preparation tank, then transfer to the surface glue cooking tank, stir evenly, pass steam, and heat to 97°C, keep warm for 20 minutes, transfer to the surface glue dilution tank and mix with water to form surface glue, prepare a surface glue solution with a concentration of 6% and a viscosity of 40mPa·s, and transfer to the surface glue storage tank for standby use.

[0074] The sizing process of the sizing machine is as follows: the surface glue solution is lifted from the surface glue storage tank to the feeding tank, and the feeding tank is lifted to the surface sizing machine to apply surface glue to the corrugated base paper. Figure 1 shown.

[0075] In the double-disc refiner process, two DD1200mm double-disc refiners are used in series for refining, with debonding type refiners, and the power of the two double-disc refiners is 480kW and 480kW respectively.

[0076] In the double-disc refiner process, the valve opening is 73%, the pulping concentration is 4.8%, the pulping degree is 34°SR, and the wet weight is 3.5 g.

[0077] Dry strength agents are added into the pulping tank: 12 kg / ton of paper of amphoteric polyacrylamide and 150 g / ton of paper of organic bromine fungicide.

[0078] 250g / ton of paper of defoaming agent is added into the white water tank outside the paper machine.

[0079] The paper machine operation parameters are: headbox lip opening 13mm, web concentration 1.1%, web speed ratio 0.95, machine speed 590m / min, drying cylinder steam pressure 540kPa for front drying, 490kPa for rear drying, and finished paper moisture 9%.

[0080] Comparative Example 1: 100% LOCC waste pulp was used, nanocellulose was removed, and other process operating conditions were the same as those in Example 3;

[0081] Comparative Example 2: CMC was removed from the surface sizing formula, and other process operating conditions were the same as those of Example 3;

[0082] Comparative Example 3: The edible corn starch in the surface sizing formula was increased to 35 kg / ton of paper, and other process operating conditions were the same as those in Example 3;

[0083] Comparative Example 4: The sizing enhancer in the surface sizing formula was increased to 5 kg / ton of paper, and the water absorption was reduced to 25 g / m 2 The other process operating conditions are the same as those in Example 3;

[0084] Comparative Example 5: The moisture content of the finished paper was controlled at 6.5%, and other process operating conditions were the same as those in Example 3;

[0085] The obtained paper was tested: basis weight: GB / T 451.2, thickness: GB / T 451.3, density = basis weight / thickness, water absorption: GB / T 1540, ring crush strength: GB / T 2679.8, breaking length: GB / T 13023, moisture: GB / T 462, folding endurance: GB / T 457.

[0086] The following data is a comparison of paper indicators:

[0087] Table 1 Comparison of paper indexes

[0088]

[0089] Through the above embodiments and comparative examples, it can be seen that:

[0090] Removing nanocellulose, removing CMC from the surface sizing formula, increasing the amount of edible corn starch in the surface sizing formula, increasing the amount of sizing enhancer in the surface sizing formula and reducing the moisture content will all lead to reduced folding endurance of the finished paper, increase paper brittleness and cause corrugated board breakage problems.

[0091] The above description is only an embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent substitution, improvement, etc. made within the spirit and principle of the present invention should be included in the scope of the claims of the present invention.

Claims

1. A production method of broken-free high-strength corrugated base paper, characterized in that Including the following process: Waste paper box → chain conveyor → D-type hydraulic pulper → unloading tank → high-concentration desander → coarse screen → low-concentration desander → fine screen → multi-disc thickener → post-concentration tank → double-disc refiner → pulping tank → pre-slurry tank → external white water tank → pulping pump → pressure screen → headbox → wire section → pressing section → front drying section → sizing machine → post-drying section → winding section → rewinding → packaging and storage; The paper machine used is a fourdrinier multi-cylinder corrugated paper machine; Adding nanocellulose into a pulping tank; The waste carton is a LOCC waste carton, and the mass ratio of the LOCC waste carton to nanocellulose is (90-95%): (10-5%); The surface glue is added to the glue sizing machine: edible corn starch 20-25kg / ton paper, CMC: 2-4kg / ton paper, and glue reinforcement: 1-3kg / ton paper.

2. The production method of crushless high-strength corrugated base paper according to claim 1, characterized in that, The preparation process of the surface adhesive is as follows: Add water to edible corn starch, CMC and sizing enhancer to dissolve in the surface glue preparation tank, then transfer to the surface glue cooking tank, stir evenly, pass steam, and heat to 93-97°C, keep warm for 18-22 minutes, transfer to the surface glue dilution tank, mix with water to form surface glue, prepare a surface glue solution with a concentration of 5-7% and a viscosity of 25-50mPa·s, and transfer to the surface glue storage tank for standby use.

3. The production method of crushless high-strength corrugated base paper according to claim 2, characterized in that, The glue applying process of the glue applicator is: the surface glue solution is lifted from the surface glue storage tank to the feeding tank, and the feeding tank is lifted to the surface glue applying the corrugated base paper.

4. The production method of crushless high-strength corrugated base paper according to claim 1, characterized in that, In the double-disk grinder process, two series grinding grinders are used for DD1200mm double-disk grinders and releasing grinders. The power of the two double-disk grinders is (450-500)kW and (450-500)kW respectively.

5. The method of producing a crushless high-strength corrugated base paper according to claim 1, characterized in that, In the double-disk grinder process, the valve opening is 70-75%, the slurry concentration is 4.5-5.0%, the slurry decomposition degree is 33-36° SR, and the wet weight is 3-4g.

6. The production method of crushless high-strength corrugated base paper according to claim 1, characterized in that, The dry strength agent is added to the slurry pool: amphoteric polyacrylamide 10-15kg / ton paper, and organic bromine fungicide 100-200g / ton paper.

7. The production method of crushless high-strength corrugated base paper according to claim 1, characterized in that, The defoaming agent is added to the white sink of the machine. 200-300g / ton of paper.

8. The production method of crushless high-strength corrugated base paper according to claim 1, characterized in that, The operating parameters of the paper machine are: the lip opening of the pulp box is 12-14mm, the grid concentration is 1.0-1.2%, the pulp grid speed ratio is 0.94-0.96, the vehicle speed is 580-600m / min, the drying cylinder is 530-550kPa before the pressure, and the drying cylinder is 480-500kPa after the drying cylinder.

9. The production method of crushless high-strength corrugated base paper according to claim 1, characterized in that, The re-rolled paper was 126-134 g, and the paper was 8-10% moisture.

10. A kind of high-strength corrugated paper without broken corrugated paper, characterized in that The production method according to any one of claims 1-9.

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