Process and apparatus for the production of flour packaging bag paper with self-adhesive properties

Abstract

This invention belongs to the field of papermaking technology, specifically relating to the production process and apparatus for self-adhesive flour packaging bags. The process includes: S1, pulping, beating, and mixing; S2, pumping the pulp to the pre-papering tank via a pulping tank pump, adding amphoteric PAM dry strength agent before the pulping tank pump; S3, pumping the pulp to the external white water tank via the pre-papering tank pump, adding PAE wet strength agent and cationic starch before the pre-papering tank pump; S4, pumping the pulp to the pressure screen via a flushing pump, adding retention aid CPAM before the pressure screen; then distributing the pulp to the wire section of the long-wire paper machine via a headbox; S5, pressing, dewatering, and drying; S6, surface sizing, winding, and packaging. The resulting packaging bag paper not only has good strength and high tear resistance, meeting the requirements of the drop bag test, but also good paper stiffness, high air permeability, and good moisture-proof performance. Simultaneously, its self-adhesive properties make the sealing process simpler and more efficient, reducing production costs and improving sealing efficiency.

Description

Technical Field

[0001] This invention belongs to the field of papermaking technology, specifically relating to the production process and apparatus for flour packaging bags with self-adhesive properties. Background Technology

[0002] In the flour packaging industry, traditional packaging bags are mostly cloth bags or woven plastic bags. While these materials meet basic packaging needs to some extent, they have many shortcomings. Cloth bags are environmentally friendly, but they are expensive, have relatively poor moisture protection, and cannot be quickly and effectively recycled. Woven plastic bags, while offering better moisture protection, cause long-term environmental pollution due to their non-degradable nature, and are also relatively expensive.

[0003] In recent years, with the increasing awareness of environmental protection and the growing popularity of the concept of sustainable development, paper flour packaging bags have gradually gained market favor due to their lightweight, economical, environmentally friendly, and good moisture-proof properties. However, traditional paper flour packaging bags usually use sewn-on paper bags. This packaging method not only increases production costs and reduces sealing efficiency, but also has a large number of paper bag layers and a complex structure, making it inconvenient for consumers to use and store. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the present invention aims to provide a production process for flour packaging bags with self-adhesive properties. Through a specific process and a special adhesive formula, flour packaging bags with excellent self-adhesive properties are produced. This packaging bag not only has high strength and tear resistance, meeting the requirements of drop tests, but also exhibits good paper stiffness, high air permeability, and excellent moisture-proof performance. Simultaneously, its self-adhesive properties simplify and streamline the sealing process, reducing production costs and improving sealing efficiency.

[0005] Another object of the present invention is to provide an apparatus for the production process of flour packaging bags with self-adhesive properties.

[0006] The technical solution adopted in this invention is as follows:

[0007] The production process of the self-adhesive flour packaging bag paper includes the following equipment connected in sequence: a softwood pulp conveying device, a softwood pulp pulper, a softwood pulp unloading tank, a softwood pulp refiner, a pulping tank, a pulping tank pump, a pre-coiling tank, a pre-coiling tank pump, an external white water tank, a flushing pump, a pressure screen, a headbox, a long-wire paper machine, a film transfer sizing machine, a drying cylinder, a winding cylinder, and a rewinder. It also includes a hardwood pulp conveying device, a hardwood pulp pulper, a hardwood pulp unloading tank, and a hardwood pulp refiner connected in sequence. The outlet of the hardwood pulp refiner is also connected to the inlet of the pulping tank.

[0008] The aforementioned long-wire paper machine includes a wire section, a press section, and a Yankee drying cylinder;

[0009] Both the softwood pulp refiner and the hardwood pulp refiner consist of three disc refiners connected in series. The first disc refiner uses a cutting type disc, while the second and third disc refiners use a dispersing type disc.

[0010] The production process of the self-adhesive flour packaging bag paper includes the following steps:

[0011] S1. Bleached sulfate softwood pulp and bleached sulfate hardwood pulp are broken down separately using a pulper, then pulped using a refiner, and finally mixed in a pulping tank. The bleached sulfate softwood pulp is made of Douglas fir with an average fiber length of 4.5-5.5 mm. Preferably, it is made of Canadian Kelp brand bleached softwood pulp with an average fiber length of 5 mm, which has high tear resistance and air permeability.

[0012] S2. The mixed pulp is pumped to the pre-paper tank through the pulping tank pump. Amphoteric PAM dry strength agent is added before the pulping tank pump to enhance the strength of the paper.

[0013] S3. The pulp is transported from the pre-papering tank to the external white water tank via the pre-papering tank pump. PAE wet strength agent and cationic starch are added before the pre-papering tank pump to further improve the physical properties of the paper. Bactericide and defoamer are added to the external white water tank to ensure the stability of the production process.

[0014] S4. The pulp in the white water tank outside the machine is transported to the pressure screen for screening and cleaning by the pulp pump to obtain clean pulp. CPAM retention aid is added before the pressure screen to improve the pulp retention rate. The clean pulp is then evenly distributed to the wire section of the long-wire paper machine through the headbox to form the initial paper sheet.

[0015] S5. The paper sheet is further pressed and dehydrated in the press section, and then sent to the Yankee drying cylinder for drying.

[0016] S6. After the dried paper is surface-sized by the film transfer sizing machine, it is wound into a paper roll by the coiling cylinder and rewinding machine, and finally the wound paper roll is packaged. The parameters of the film transfer sizing machine are: front metering bar model V30, linear pressure 20kN / m; back metering bar model V30, linear pressure 20kN / m.

[0017] The surface sizing agents used include: 10-15 kg / ton of cassava oxidized starch, 20-25 kg / ton of polyvinyl alcohol, 3-5 kg / ton of AKD sizing agent, and 1-2 kg / ton of AKD synergist. The degree of hydrolysis of polyvinyl alcohol is 88-90%, preferably polyvinyl alcohol 1788 produced by Anhui Wanwei Group Co., Ltd., with a degree of hydrolysis of 88%. The lower degree of hydrolysis gives it better solubility and stronger adhesion, which is beneficial to the adhesion of self-adhesive products.

[0018] In step S1, the beating concentration of bleached sulfate softwood pulp is 4.0-4.5%, the beating degree is 40-45°SR, and the wet weight is 4-6g; the beating concentration of bleached sulfate hardwood pulp is 4.5-5.0%, the beating degree is 30-35°SR, and the wet weight is 1.5-2.5g; the mixing ratio of bleached sulfate softwood pulp and bleached sulfate hardwood pulp in the pulping tank is (70wt.%-80wt.%):(20wt.%-30wt.%).

[0019] In step S2, the amount of amphoteric PAM dry strength agent added is 20-25 kg / ton of paper.

[0020] In step S3, the amount of PAE wet strength agent added is 25-35 kg / ton of paper, and the amount of cationic starch added is 15-20 kg / ton of paper.

[0021] In step S3, the bactericide is an organic bromine bactericide; the amount of bactericide added is 200-300g / ton of paper; the defoamer is a polyether defoamer; the amount of defoamer added is 100-200g / ton of paper.

[0022] In step S4, the amount of CPAM added is 150-200g / ton of paper.

[0023] The speed of the long-wire paper machine is 300-400m / min, the lip opening is 17-19mm, the vibration amplitude is 23-27mm, the vibration frequency is 170-190 times / min, the wire density is 0.7-0.9%, the steam pressure of the Yankee drying cylinder is 500-600kPa, and the temperature is 90-100℃.

[0024] In step S6, the paper dryness after entering the film transfer sizing machine is ≥90%, and the paper dryness after exiting the film transfer sizing machine is ≥70%; the paper pick-up amount of surface sizing agent is: 1.5-2.5 g / m² on the front side. 2 The reverse side contains 1.5-2.5g / m 2 .

[0025] The preparation method of the surface sizing agent is as follows: 10-15 parts by weight of oxidized cassava starch, 20-25 parts by weight of polyvinyl alcohol and 270 parts by weight of water are stirred evenly and steam is introduced to raise the temperature to 93-97℃ and keep it at that temperature for 18-22 minutes. Then, 3-5 parts by weight of AKD sizing agent and 1-2 parts by weight of AKD sizing agent synergist are added to obtain a surface sizing agent with a concentration of 11-13% and a viscosity of 25-35 mPa·s.

[0026] The apparatus used for the self-adhesive flour packaging bag paper includes, in sequence, a softwood pulp conveying device, a softwood pulp pulper, a softwood pulp unloading tank, a softwood pulp refiner, a pulping tank, a pulping tank pump, a pre-washing tank, a pre-washing tank pump, an external white water tank, a flushing pump, a pressure screen, a headbox, a long-wire paper machine, a film transfer sizing machine, a drying cylinder, a winding cylinder, and a rewinder. It also includes, in sequence, a hardwood pulp conveying device, a hardwood pulp pulper, a hardwood pulp unloading tank, and a hardwood pulp refiner. The outlet of the hardwood pulp refiner is also connected to the inlet of the pulping tank.

[0027] The aforementioned long-wire paper machine includes a wire section, a press section, and a Yankee drying cylinder;

[0028] Both the softwood pulp refiner and the hardwood pulp refiner consist of three disc refiners connected in series. The first disc refiner uses a cutting type disc, while the second and third disc refiners use a dispersing type disc.

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

[0030] (1) The production process of the flour packaging bag paper with self-adhesive properties described in this invention uses environmentally friendly paper materials, which are easier to degrade and recycle than traditional plastic or cloth bag materials, thus reducing environmental pollution. Through special surface coating process and ratio, the flour packaging bag paper produced by this invention has good self-adhesive properties, realizes rapid sealing of packaging bags, reduces production costs, and improves sealing efficiency.

[0031] (2) The production process of the flour packaging bag paper with self-adhesive properties described in this invention uses softwood pulp fiber with high wet weight. After special pulping process, more hydrogen bonds are formed, which makes the produced flour bag packaging paper have high tensile strength and high tear resistance, meeting the requirements of the drop test. AKD sizing agent and AKD synergist are added during the surface sizing process, which effectively improves the moisture resistance of the paper and ensures the strength of the flour bag in a relatively humid environment.

[0032] (3) The device used in the self-adhesive flour packaging bag paper of the present invention employs a long wire and large cylinder paper machine, which makes the smoothness of the front of the paper moderate, ensuring the clarity of printing and avoiding the problem of stacking difficulties caused by excessive smoothness, thus improving the quality. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the apparatus used in the production process of the self-adhesive flour packaging bag paper described in this invention.

[0034] In the diagram: 1. Softwood pulp conveying device; 2. Softwood pulp pulper; 3. Softwood pulp unloading tank; 4. Softwood pulp refiner; 5. Pulp tank; 6. Pulp tank pump; 7. Pre-wash tank; 8. Pre-wash tank pump; 9. External white water tank; 10. Pulp flushing pump; 11. Pressure screen; 12. Headbox; 13. Long-wire paper machine; 14. Film transfer sizing machine; 15. Drying cylinder; 16. Wrapping cylinder; 17. Rewinder; 18. Hardwood pulp conveying device; 19. Hardwood pulp pulper; 20. Hardwood pulp unloading tank; 21. Hardwood pulp refiner. Detailed Implementation

[0035] The present invention will be further described below with reference to the embodiments, but these embodiments do not limit the implementation of the present invention.

[0036] Unless otherwise specified, the raw materials used in the examples and comparative examples are all commercially available materials, and the process methods used in the examples and comparative examples are all conventional methods in the art.

[0037] The following is a description of some of the raw materials used in the examples and comparative examples:

[0038] Polyvinyl alcohol 1799 (degree of polymerization 1700, degree of alcoholysis 99%) was purchased from Anhui Wanwei Group Co., Ltd.

[0039] Polyvinyl alcohol 1788 (degree of polymerization 1700, degree of alcoholysis 88%) was purchased from Anhui Wanwei Group Co., Ltd.

[0040] HL-15, an organic bromine bactericide, was purchased from Zhejiang Chuanhua Huayang Chemical Co., Ltd.

[0041] Polyether defoamer DF-9 was purchased from Zhejiang Chuanhua Huayang Chemical Co., Ltd.

[0042] The Canadian Kelly brand bleached softwood pulp (made of Douglas fir with an average fiber length of 5mm) was purchased from West Fraser Wood Industries, Canada.

[0043] Moon Brand bleached softwood pulp (made of spruce, with an average fiber length of 3.5mm), purchased from Mercer International, Canada.

[0044] like Figure 1As shown in the embodiment of the present invention, the production process of flour packaging bag paper with self-adhesive properties uses an apparatus that includes, in sequence, a softwood pulp conveying device 1, a softwood pulp pulper 2, a softwood pulp unloading tank 3, a softwood pulp refiner 4, a pulping tank 5, a pulping tank pump 6, a pre-coating tank 7, a pre-coating tank pump 8, an external white water tank 9, a flushing pump 10, a pressure screen 11, a headbox 12, a long-wire paper machine 13, a film transfer sizing machine 14, a drying cylinder 15, a winding cylinder 16, and a rewinder 17. It also includes, in sequence, a hardwood pulp conveying device 18, a hardwood pulp pulper 19, a hardwood pulp unloading tank 20, and a hardwood pulp refiner 21. The outlet of the hardwood pulp refiner 21 is also connected to the inlet of the pulping tank 5.

[0045] The aforementioned long-wire paper machine 13 includes a wire section, a press section, and a Yankee drying cylinder;

[0046] The softwood pulp refiner 4 and the hardwood pulp refiner 21 are both composed of three disc mills connected in series. The first disc mill uses a cutting type milling disc, while the second and third disc mills use a dispersing type milling disc.

[0047] The production process of the self-adhesive flour packaging bag paper includes the following steps:

[0048] S1. Bleached sulfate softwood pulp and bleached sulfate hardwood pulp are transported to softwood pulp mill 2 and hardwood pulp mill 19 respectively through softwood pulp conveying device 1 and hardwood pulp conveying device 18 for pulping. After being pulped by softwood pulp refiner 4 and hardwood pulp refiner 21, they are sent to pulping tank 5 for mixing. Among them, the bleached sulfate softwood pulp is Canadian Kelp brand bleached softwood pulp.

[0049] S2. The mixed slurry is pumped to the pre-pumping tank through the slurry tank pump, and amphoteric PAM dry strength agent is added before the slurry tank pump.

[0050] S3. The slurry is transported from the pre-slurry pool to the external white water tank by the pre-slurry pool pump. PAE wet strength agent and cationic starch are added before the pre-slurry pool pump. Organic bromide bactericide HL-15 and polyether defoamer DF-9 are added to the external white water tank.

[0051] S4. The pulp in the white water tank outside the machine is transported to the pressure screen for screening and cleaning by the pulp pump to obtain clean pulp. CPAM retention aid is added before the pressure screen. The clean pulp is then evenly distributed to the wire section of the long-wire paper machine through the headbox to form the initial paper sheet.

[0052] S5. The paper sheet is further pressed and dehydrated in the press section, and then sent to the Yankee drying cylinder for drying.

[0053] S6. After the dried paper is surface-sized by the film transfer sizing machine, it is wound into a paper roll by the coiling cylinder and rewinding machine, and finally the wound paper roll is packaged. The parameters of the film transfer sizing machine are: front metering bar model V30, linear pressure 20kN / m; back metering bar model V30, linear pressure 20kN / m.

[0054] Example 1

[0055] The production process parameters for the self-adhesive flour packaging bag paper are as follows:

[0056] In step S1, the beating concentration of the bleached sulfate softwood pulp is 4.0%, the beating degree is 40°SR, and the wet weight is 6g; the beating concentration of the bleached sulfate hardwood pulp is 4.5%, the beating degree is 30°SR, and the wet weight is 2.5g; the mixing mass ratio of the bleached sulfate softwood pulp and the bleached sulfate hardwood pulp in the pulping tank is 70%:30%.

[0057] In step S2, the amount of amphoteric PAM dry strength agent added is 20 kg / ton of paper.

[0058] In step S3, the amount of PAE wet strength agent added is 25 kg / ton of paper, and the amount of cationic starch added is 15 kg / ton of paper.

[0059] In step S3, the amount of organic bromine bactericide HL-15 added is 200g / ton of paper; the amount of polyether defoamer DF-9 added is 100g / ton of paper.

[0060] In step S4, the amount of CPAM added is 150g / ton of paper.

[0061] The long-wire paper machine has a speed of 300m / min, a lip opening of 17mm, a vibration amplitude of 23mm, a vibration frequency of 170 times / min, a wire density of 0.7%, and a steam pressure of 500kPa and a temperature of 90℃ in the Yankee drying cylinder.

[0062] In step S6, the paper dryness after entering the film transfer sizing machine is 91%, and the paper dryness after exiting the film transfer sizing machine is 70%; the paper pick-up amount of surface sizing agent is 1.5 g / m² on the front side. 2 1.5g / m² on the reverse side 2 ;

[0063] The preparation method of the surface sizing agent is as follows: 10 parts by weight of oxidized cassava starch, 20 parts by weight of polyvinyl alcohol 1788 and 270 parts by weight of water are stirred evenly and steam is introduced to raise the temperature to 93°C and keep it at that temperature for 18 minutes. Then, 3 parts by weight of AKD sizing agent and 1 part by weight of AKD synergist are added to obtain a surface sizing agent with a concentration of 11% and a viscosity of 25 mPa·s.

[0064] Example 2

[0065] The production process parameters for the self-adhesive flour packaging bag paper are as follows:

[0066] In step S1, the beating concentration of the bleached sulfate softwood pulp is 4.5%, the beating degree is 45°SR, and the wet weight is 4g; the beating concentration of the bleached sulfate hardwood pulp is 5.0%, the beating degree is 35°SR, and the wet weight is 1.5g; the mixing mass ratio of the bleached sulfate softwood pulp and the bleached sulfate hardwood pulp in the pulping tank is 80%:20%.

[0067] In step S2, the amount of amphoteric PAM dry strength agent added is 25 kg / ton of paper.

[0068] In step S3, the amount of PAE wet strength agent added is 35 kg / ton of paper, and the amount of cationic starch added is 20 kg / ton of paper.

[0069] In step S3, the amount of organic bromine bactericide HL-15 added is 300g / ton of paper; the amount of polyether defoamer DF-9 added is 200g / ton of paper.

[0070] In step S4, the amount of CPAM added is 200g / ton of paper.

[0071] The long-wire paper machine has a speed of 400 m / min, a lip opening of 19 mm, a vibration amplitude of 27 mm, a vibration frequency of 190 times / min, a wire density of 0.9%, and a steam pressure of 600 kPa and a temperature of 100℃ in the Yankee drying cylinder.

[0072] In step S6, the paper dryness after entering the film transfer sizing machine is 92%, and the paper dryness after exiting the film transfer sizing machine is 72%; the paper pick-up amount of surface sizing agent is 2.5 g / m² on the front side. 2 2.5g / m² on the reverse side 2 ;

[0073] The preparation method of the surface sizing agent is as follows: 15 parts by weight of oxidized cassava starch, 25 parts by weight of polyvinyl alcohol 1788 and 270 parts by weight of water are stirred evenly and steam is introduced to raise the temperature to 97°C and keep it at that temperature for 22 minutes. Then, 5 parts by weight of AKD sizing agent and 2 parts by weight of AKD synergist are added to obtain a surface sizing agent with a concentration of 13% and a viscosity of 35 mPa·s.

[0074] Example 3

[0075] The production process parameters for the self-adhesive flour packaging bag paper are as follows:

[0076] In step S1, the beating concentration of the bleached sulfate softwood pulp is 4.2%, the beating degree is 42°SR, and the wet weight is 5.0g; the beating concentration of the bleached sulfate hardwood pulp is 4.7%, the beating degree is 33°SR, and the wet weight is 2.0g; the mixing mass ratio of the bleached sulfate softwood pulp and the bleached sulfate hardwood pulp in the pulping tank is 75%:25%.

[0077] In step S2, the amount of amphoteric PAM dry strength agent added is 22 kg / ton of paper.

[0078] In step S3, the amount of PAE wet strength agent added is 30 kg / ton of paper, and the amount of cationic starch added is 18 kg / ton of paper.

[0079] In step S3, the amount of organic bromine bactericide HL-15 added is 250g / ton of paper; the amount of polyether defoamer DF-9 added is 150g / ton of paper.

[0080] In step S4, the amount of CPAM added is 180g / ton of paper.

[0081] The long-wire paper machine has a speed of 350 m / min, a lip opening of 18 mm, a vibration amplitude of 25 mm, a vibration frequency of 180 times / min, a wire density of 0.8%, and a steam pressure of 550 kPa and a temperature of 95℃ in the Yankee drying cylinder.

[0082] In step S6, the paper dryness after entering the film transfer sizing machine is 93%, and the paper dryness after exiting the film transfer sizing machine is 72%; the paper pick-up amount of surface sizing agent is 2g / m² on the front side. 2 2g / m 2 ;

[0083] The preparation method of the surface sizing agent is as follows: 12 parts by weight of oxidized cassava starch, 23 parts by weight of polyvinyl alcohol 1788 and 270 parts by weight of water are stirred evenly and steam is introduced to raise the temperature to 95°C and keep it at that temperature for 20 minutes. Then, 4 parts by weight of AKD sizing agent and 1.5 parts by weight of AKD synergist are added to obtain a surface sizing agent with a concentration of 12% and a viscosity of 30 mPa·s.

[0084] Comparative Example 1

[0085] The difference from Example 3 is that polyvinyl alcohol 1788 is replaced with polyvinyl alcohol 1799, otherwise it is the same as Example 3.

[0086] Comparative Example 2

[0087] The difference from Example 3 is that the Canadian Kelly brand bleached softwood pulp is replaced with Canadian Moon brand bleached softwood pulp, otherwise it is the same as Example 3.

[0088] Comparative Example 3

[0089] The difference from Example 3 is that AKD sizing agent and AKD synergist are not added to the surface sizing agent formulation components, but otherwise the same as Example 3.

[0090] Comparative Example 4

[0091] The difference from Example 3 is that the long-wire large-cylinder paper machine is replaced with a long-wire multi-cylinder paper machine, otherwise it is the same as Example 3.

[0092] The performance of the flour packaging bag paper prepared in Examples 1-3 and Comparative Examples 1-4 was tested respectively, and the test methods are as follows:

[0093] Quantitative (g / m 2 Tests were conducted in accordance with GB / T 451.2-2002.

[0094] Moisture content (wt.%): Tested according to GB / T 462-2003;

[0095] Thickness (μm): Tested according to GB / T 451.3-2002;

[0096] Tensile strength (N): Tested according to GB / T12914-2008;

[0097] Water absorption (g / m 2 Tests were conducted in accordance with GB / T 1540-2002.

[0098] Smoothness (s): Tested according to GB / T 456-2002;

[0099] Water absorption (g / m 2Tests were conducted in accordance with GB / T 1540-2002.

[0100] Tear strength (mN): Tested according to GB / T 455-2002;

[0101] Wet tensile strength (N / 15mm): Tested according to GB / T465.2-2008;

[0102] Peel strength (N / 15mm): Tested according to GB / T 10004-2008;

[0103] The test results are shown in Table 1:

[0104] Table 1 Performance Test Results

[0105]

[0106] As shown in Table 1, compared with Example 3, replacing polyvinyl alcohol 1788 with polyvinyl alcohol 1799 in Comparative Example 1 reduced the paper peel strength, leading to poor paper adhesion. Compared with Example 3, replacing Canadian Kelly brand bleached softwood pulp with Canadian Moon brand bleached softwood pulp in Comparative Example 2 reduced both the tensile strength and tear strength of the paper, resulting in failure to meet the bag-drop test requirements. Compared with Example 3, omitting AKD sizing agent and AKD synergist from the surface sizing agent formulation in Comparative Example 3 reduced water absorption, leading to increased moisture absorption by the paper. Compared with Example 3, replacing the long-wire large-cylinder paper machine with a long-wire multi-cylinder paper machine in Comparative Example 4 resulted in lower smoothness on the front of the paper and unclear printing.

Claims

1. A production process for flour packaging bags with self-adhesive properties, characterized in that, The apparatus used includes, in sequence, a softwood pulp conveying device (1), a softwood pulp pulper (2), a softwood pulp unloading tank (3), a softwood pulp refiner (4), a pulping tank (5), a pulping tank pump (6), a pre-wash tank (7), a pre-wash tank pump (8), an external white water tank (9), a flushing pump (10), a pressure screen (11), a headbox (12), a long-wire paper machine (13), a film transfer sizing machine (14), a drying cylinder (15), a roll cylinder (16), and a rewinder (17), and also includes, in sequence, a hardwood pulp conveying device (18), a hardwood pulp pulper (19), a hardwood pulp unloading tank (20), and a hardwood pulp refiner (21), the outlet of which is also connected to the inlet of the pulping tank (5); The long-wire paper machine (13) includes a wire section, a press section and a Yankee drying cylinder; The softwood pulp refiner (4) and the hardwood pulp refiner (21) are both composed of three disc refiners connected in series. The first disc refiner uses a cutting type grinding disc, while the second and third disc refiners use a dispersing type grinding disc. The production process of the self-adhesive flour packaging bag paper includes the following steps: S1. Bleached sulfate softwood pulp and bleached sulfate hardwood pulp are broken down separately by a pulper, then pulped by a refiner and sent to a pulping tank for mixing; wherein, the bleached sulfate softwood pulp is made of Douglas fir with an average fiber length of 4.5-5.5mm. S2. The mixed slurry is pumped to the pre-pumping tank through the slurry tank pump, and amphoteric PAM dry strength agent is added before the slurry tank pump. S3. The slurry is transported from the pre-scoop pool to the external white water tank by the pre-scoop pool pump. PAE wet strength agent and cationic starch are added before the pump of the pre-scoop pool pump, and bactericide and defoamer are added to the external white water tank. S4. The pulp in the white water tank outside the machine is transported to the pressure screen for screening and cleaning by the pulp pump to obtain clean pulp. CPAM retention aid is added before the pressure screen. The clean pulp is then evenly distributed to the wire section of the long-wire paper machine through the headbox to form the initial paper sheet. S5. The paper sheet is further pressed and dehydrated in the press section, and then sent to the Yankee drying cylinder for drying. S6. After the dried paper is surface-sized by a film transfer sizing machine, it is wound into a paper roll by a coiling cylinder and a rewinding machine, and finally the wound paper roll is packaged. The surface sizing agents used include: 10-15 kg / ton of cassava oxidized starch, 20-25 kg / ton of polyvinyl alcohol, 3-5 kg / ton of AKD sizing agent, and 1-2 kg / ton of AKD synergist. The degree of alcoholysis of polyvinyl alcohol is 88-90%. The preparation method of the surface sizing agent is as follows: 10-15 parts by weight of oxidized cassava starch, 20-25 parts by weight of polyvinyl alcohol and 270 parts by weight of water are stirred evenly and steam is introduced to raise the temperature to 93-97℃ and keep it at that temperature for 18-22 minutes. Then, 3-5 parts by weight of AKD sizing agent and 1-2 parts by weight of AKD synergist are added to obtain a surface sizing agent with a concentration of 11-13% and a viscosity of 25-35 mPa·s. In step S1, the beating concentration of bleached sulfate softwood pulp is 4.0-4.5%, the freeness is 40-45°SR, and the wet weight is 4-6g; the beating concentration of bleached sulfate hardwood pulp is 4.5-5.0%, the freeness is 30-35°SR, and the wet weight is 1.5-2.5g; the mixing ratio of bleached sulfate softwood pulp and bleached sulfate hardwood pulp in the pulping tank is (70wt.%-80wt.%):(20wt.%-30wt.%). The aforementioned long-wire paper machine has a machine speed of 300-400m / min, a lip opening of 17-19mm, a shaking amplitude of 23-27mm, a shaking frequency of 170-190 times / min, a wire density of 0.7-0.9%, and a steam pressure of 500-600kPa and a temperature of 90-100℃ in the Yankee drying cylinder.

2. The production process of the self-adhesive flour packaging bag paper according to claim 1, characterized in that, In step S2, the amount of amphoteric PAM dry strength agent added is 20-25 kg / ton of paper.

3. The production process of the self-adhesive flour packaging bag paper according to claim 1, characterized in that, In step S3, the amount of PAE wet strength agent added is 25-35 kg / ton of paper, and the amount of cationic starch added is 15-20 kg / ton of paper.

4. The production process of the self-adhesive flour packaging bag paper according to claim 1, characterized in that, In step S3, the bactericide is an organic bromine bactericide, and the amount of bactericide added is 200-300g / ton of paper; the defoamer is a polyether defoamer, and the amount of defoamer added is 100-200g / ton of paper.

5. The production process of the self-adhesive flour packaging bag paper according to claim 1, characterized in that, In step S4, the amount of CPAM added is 150-200g / ton of paper.

6. The production process of the self-adhesive flour packaging bag paper according to claim 1, characterized in that, In step S6, the paper dryness after entering the film transfer sizing machine is ≥90%, and the paper dryness after exiting the film transfer sizing machine is ≥70%; the paper pick-up amount of surface sizing agent is: 1.5-2.5 g / m² on the front side. 2 The reverse side contains 1.5-2.5g / m 2 .

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