A method for preparing straw cellulose pulp board by biomachinery and application thereof in box board paper production

Abstract

The application provides a method for preparing straw cellulose pulp board by a biomachanical method and application in box board paper production, and belongs to the technical field of papermaking process, and particularly relates to a biological swelling bacterial agent, a biological disappearing bacterial agent and application of the biological swelling bacterial agent and the biological disappearing bacterial agent in straw pulping, wherein the biological swelling bacterial agent comprises bacillus licheniformis, bacillus subtilis, bacillus pumilus and bacillus cereus; the biological disappearing bacterial agent comprises bacillus licheniformis and bacillus subtilis subsp. subtilis; and the biological swelling bacterial agent and the biological disappearing bacterial agent are combined with a mechanical pulping method to prepare paper by pulping, the obtained papermaking pulp has high pulp yield, high paper whiteness, and certain advantages in tensile index, ring pressure index, tear index and burst index.

Description

Technical Field

[0001] This invention belongs to the field of papermaking technology, specifically relating to a method for preparing straw cellulose pulp board by biomechanical means and its application in the production of linerboard. Background Technology

[0002] As a pillar industry related to the national economy and people's livelihood, the paper industry is highly dependent on raw materials. In recent years, the shortage of raw materials in domestic wood pulp papermaking has made low-cost straw pulp papermaking a focus of attention, and the abundant straw resources in China urgently need to be developed and utilized.

[0003] Currently, the traditional pulping method is mainly chemical pulping. However, chemical pulping generates a large amount of wastewater containing residual lignin and chemical substances during the pulping process, causing pollution problems in papermaking. Therefore, solving or improving wastewater pollution in the pulp and paper industry and developing pollution-free or low-pollution pulping and papermaking technologies are urgently needed.

[0004] Lignin is dispersed around cellulose, but the two are usually not directly chemically bonded together. Hemicellulose runs through the space between lignin and cellulose, acting as a connector between them, thus forming a very strong lignin-hemicellulose-cellulose network structure, namely the lignocellulose array. The presence of this array results in low mechanical pulping yield, poor mechanical strength, low whiteness, and easy yellowing and oxidation.

[0005] Chinese patent document CN108442162A (application number 201810338110.7) discloses a method for bio-pulping of crop straw. The method involves treating chopped crop straw with a compound bio-enzyme preparation to obtain coarse crop straw pulp, followed by grinding and fiber separation to obtain fine crop straw pulp, and then subjecting it to a second treatment with microbial agents to obtain fine crop straw pulp. The fine crop straw pulp is then bleached to obtain papermaking pulp. The compound bio-enzyme preparation includes lignin peroxidase, xylanase, laccase, pectinase, and pulping enzyme; the compound microbial agents include anaerobic Bacillus, *Vitis radiata*, brown rot fungi, and polypores.

[0006] Chinese patent document CN114921992A (application number 202210616865.5) discloses a biomechanical preparation method using compound bioenzyme treatment. The method utilizes wheat straw as raw material, first soaking it with compound bioenzymes to adjust the pH to the optimal pH for the enzymes. After some lignin, hemicellulose, and gums are dissolved from the straw, it is then extruded using rollers to achieve a filamentous state. A second bioenzyme treatment further softens the straw. The softened straw is then milled and screened to obtain paper pulp. The compound bioenzyme preparation includes pectinase, xylanase, amylase, cellulase, and neutral protease.

[0007] Chinese patent document CN114774303A (application number: 202210246052.1) discloses a microbial agent for desiliconizing straw pulp raw materials and its application in straw pulp desiliconization pulping. Addressing the problem of silicon interference in black liquor alkali recovery caused by high silicon content in straw pulp raw materials, the invention employs a microbial agent pretreatment method to degrade the outer layer of straw, promoting silicon release. This removes most of the silicon from the straw pulp raw materials during the pretreatment stage, reducing the silicon content in the black liquor and improving the silicon interference problem faced by traditional pulping methods due to excessively high silicon content in the black liquor. The microbial agent includes Bacillus pumilus, Bacillus cereus, and Bacillus subtilis, which are significantly different from the technical problems and effects to be solved by this invention.

[0008] Although biopulping is a clean and environmentally friendly pulping process, the enzymes used in biodegradation are expensive and have a low reuse rate. Furthermore, the decomposition effect of using a single enzyme in biodegradation is not ideal, requiring the use of compound enzyme preparations, which further increases the production cost of biopulping. Summary of the Invention

[0009] To address the shortcomings of existing technologies, this invention proposes a biomechanical method for preparing straw cellulose pulp boards and its application in linerboard production.

[0010] This invention provides a method for producing pulp boards using straw mechanical pulp through biological swelling and biological descaling.

[0011] The straw pulping method of this invention involves biological swelling and biological defoaming treatment of the raw materials before mechanical pulping, which significantly reduces the discharge of process wastewater and papermaking black liquor, making it cleaner and more environmentally friendly. Simultaneously, the biological swelling and defoaming treatment results in paper with excellent properties after mechanical pulping, showing a significant improvement in mechanical strength and other aspects compared to untreated mechanical pulping.

[0012] The technical solution of the present invention is as follows:

[0013] A bio-swelling agent for straw pulping includes Bacillus licheniformis, Bacillus subtilis, Bacillus pumilus, and Bacillus cereus.

[0014] According to a preferred embodiment of the present invention, the bacterial species composition of the biological swelling agent is as follows: Bacillus licheniformis bacterial solution, Bacillus subtilis bacterial solution, Bacillus pumilus bacterial solution and Bacillus cereus bacterial solution are compounded in a mass ratio of (1~3):(1~3):(1~3):(1~3).

[0015] More preferably, the viable count of each bacterial culture solution is 1.0 × 10⁻⁶. 9 cfu / mL ~1.0×10 11 cfu / mL.

[0016] According to a preferred embodiment of the present invention, the bio-swelling agent includes Bacillus licheniformis CICC 10086, Bacillus subtilis CICC 10028, Bacillus pumilus CICC 22395 and Bacillus cereus CICC 10184.

[0017] The preparation method of the above-mentioned biological swelling agent includes the following steps:

[0018] (1) Activation of bacterial strains: Take the target bacterial strains and inoculate them into liquid culture medium for activation culture;

[0019] (2) Expanded compounding: The activated target strain is expanded cultured, and the expanded culture liquid is mixed and compounded in proportion to obtain the biological swelling agent.

[0020] According to a preferred embodiment of the present invention, in steps (1) and (2), the liquid culture medium is LB liquid culture medium.

[0021] According to a preferred embodiment of the present invention, in step (1), the culture conditions are 35-40°C and 150 °C. Incubate at 200 rpm for 1-2 days; more preferably, incubate at 37℃ and 150-180 rpm for 1-2 days.

[0022] According to a preferred embodiment of the present invention, in step (2), the culture conditions are 35-40°C and 150 °C. Incubate at 200 rpm for 2-4 days; more preferably, incubate at 37℃ and 150-180 rpm for 2-4 days.

[0023] A biological antimicrobial agent for straw pulping includes Bacillus licheniformis and Bacillus subtilis subsp. subtilis.

[0024] According to a preferred embodiment of the present invention, the bacterial composition of the biological antimicrobial agent is as follows: a mixture of Bacillus licheniformis bacterial solution and Bacillus subtilis subtilis bacterial solution in a mass ratio of (1~3):(1~3).

[0025] More preferably, the viable count of each bacterial culture solution is 1.0 × 10⁻⁶. 9 cfu / mL ~1.0×10 11 cfu / mL.

[0026] According to a preferred embodiment of the present invention, the biological antimicrobial agent includes Bacillus licheniformis CICC 10086 and Bacillus subtilis subsp. subtilis CICC 10085.

[0027] The preparation method of the above-mentioned biological antimicrobial agent for straw pulping includes the following steps:

[0028] ① Activation of bacterial strains: Take the target bacterial strains and inoculate them into liquid culture medium for activation culture;

[0029] ② Expanded compounding: The activated target strain is cultured on a larger scale, and the cultured bacterial solutions are mixed and compounded in proportion to obtain a biological antimicrobial agent.

[0030] According to a preferred embodiment of the present invention, in steps ① and ②, the liquid culture medium is LB liquid culture medium.

[0031] According to a preferred embodiment of the present invention, in step ①, the culture conditions are 35~40℃ and 150-200rpm for 1~2 days; more preferably, the conditions are 37℃ and 150~180rpm for 1~2 days.

[0032] According to a preferred embodiment of the present invention, in step ②, the culture conditions are 35~40℃ and 150-200rpm for 2~4 days; more preferably, the conditions are 37℃ and 150~180rpm for 2~4 days.

[0033] Application of the above-mentioned biological swelling agent and biological anti-swelling agent in straw pulping.

[0034] According to a preferred embodiment of the present invention, a method for using biological swelling agents and biological scavenging agents in straw pulping and papermaking includes the following steps:

[0035] I. Compression and Washing: The straw is compressed, washed, and dried for later use;

[0036] II. Bio-swelling: Transfer the dried straw to a swelling tank, add LB medium, then add bio-swelling agent, mix evenly, and soak for 1-2 days; after draining the straw, add water to the pulping raw material, stir, and then process it through a high-consistency pulping machine for mechanical pulping to obtain bio-swelled coarse pulp.

[0037] III. Biological defoaming: Add biological defoaming agent to the biologically swelled crude slurry, and keep it in a water bath at 55℃~60℃ for 6h~8h to carry out biological defoaming;

[0038] IV. Pulping: The pulp after biological defoaming is transferred to a pulp screener to collect fibers that meet the papermaking conditions. The fibers are then laid into a pulp beater for pulping. Pulping is stopped when the freeness is 40±2°SR to obtain straw papermaking pulp.

[0039] V. Pulpboard: The straw pulp obtained in step IV is processed into pulpboards using a pulpboard machine to obtain pulpboards. The concentration of the straw pulp at the feedstock is 1.3% to 2.0%.

[0040] VI. Slurry plate swelling: Place the oven-dry slurry plate in a swelling tank, add LB medium, then add biological swelling agent, mix evenly, and soak for 1-2 days to swell; after filtration, obtain biological pretreated slurry;

[0041] VII. Pulping and Papermaking: The pretreated biological pulp is fed into a pulper for pulping. Pulping is stopped at a freeness of 78±2°SR. After treatment by a fiber desorber, the pulp is formed on a paper machine to obtain linerboard with a basis weight of 80 g / m². 2 ~100g / m 2 .

[0042] According to a preferred embodiment of the present invention, in steps II, III, and VI, the amount of the biological swelling agent and the biological anti-swelling agent added is 10% to 15% of the liquid volume.

[0043] According to a preferred embodiment of the present invention, in step II, the swelling conditions are 30-40°C for 2-4 days; more preferably, 37°C for 2-3 days.

[0044] Beneficial effects

[0045] 1. This invention provides a biological swelling agent. In the biological pretreatment of straw, the various microbial species mutually benefit each other and work synergistically to promote the efficient degradation of cellulose, hemicellulose and lignin. At the same time, other secondary metabolites can effectively inhibit the growth of pathogenic bacteria and prevent contamination by miscellaneous bacteria.

[0046] 2. This invention provides a biological anti-fouling agent. In the biological anti-fouling of straw pulp, the various bacterial species mutually benefit each other and work synergistically to provide a rich complex enzyme system, which greatly shortens the anti-fouling time and jointly promotes the separation of cellulose and lignin and inhibits the formation of LCC structure.

[0047] 3. This invention employs a combination of biological swelling agents and biological anti-fouling agents in mechanical pulping for papermaking. The resulting pulp has a high yield, high paper brightness, and advantages in tensile index, ring crush index, tear index, and bursting strength. In actual production, large-scale modifications to mechanical pulping workshops and equipment are unnecessary; only a biological anti-fouling workshop needs to be added to the existing workshop, utilizing waste steam generated during production for heating. This technology has a clear design concept, strong adaptability and universality, and a high degree of industrialization. Utilizing biological swelling agents and biological anti-fouling agents for biological pulping treatment avoids the use of large amounts of chemical agents in traditional papermaking, reduces wastewater discharge in traditional pulping processes, lowers production costs, and is both technologically advanced and environmentally friendly. Attached Figure Description

[0048] Figure 1 This is a flowchart of the pulp board and linerboard production process.

[0049] Figure 2 This is a comparison diagram of the paper prepared in Example 2 and Comparative Example 2. Detailed Implementation

[0050] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but the implementation of the present invention is not limited thereto.

[0051] Unless otherwise specified, the drugs and reagents used in the examples are common products already on the market. All contents not described in detail in the examples are based on the prior art.

[0052] Microorganisms involved in the examples:

[0053] Bacillus licheniformis: purchased from China Industrial Microbiology Preservation and Management Center, strain number: CICC 10086;

[0054] Bacillus subtilis: purchased from China Industrial Microbial Culture Collection Center, strain number: CICC 10028;

[0055] Bacillus pumilus: purchased from China Industrial Microbial Culture Collection Center, strain number: CICC 22395;

[0056] Bacillus cereus: purchased from China Industrial Microbial Culture Collection Center, strain number: CICC 10184;

[0057] Bacillus licheniformis: purchased from China Industrial Microbial Culture Collection Center, strain number: CICC 10084;

[0058] Bacillus subtilis subsp. subtilis: purchased from China Industrial Microbiology Preservation and Management Center, strain number: CICC 10085.

[0059] Preparation of culture media in the examples: (all percentages by mass)

[0060] The composition of LB medium is as follows: 1% sodium chloride, 1% peptone, 0.5% yeast extract, and 2% agar (liquid medium does not contain agar).

[0061] Example 1

[0062] The composition of microbial strains in the biological swelling agent is determined as follows:

[0063] (1) Obtaining the source of bacteria: Collect straw waste and farmland soil samples, soak them in 0.85% physiological saline for 2-3 days to allow the microorganisms in the samples to be fully dispersed in the liquid environment;

[0064] (2) Enrichment culture: Take a certain volume of the bacterial liquid from step (1) and transfer it to LB medium (liquid) for 2-3 days at a temperature of 37℃ and 180 rpm.

[0065] (3) Dilution and spreading: After serial dilution, take 200 μL of the diluted bacterial solution and spread it evenly on LB medium (solid). Incubate for 1-2 days at 37℃.

[0066] (4) Liquid transfer: Select individual colonies from different cultures and transfer them to LB medium (liquid). Incubate for 2-3 days at 37°C and 180 rpm.

[0067] (5) Streak purification: Streak the bacterial solution from step (4) onto LB medium (solid) and incubate for 1-2 days at a temperature of 37°C;

[0068] (6) Liquid expansion: Transfer the single colony purified and cultured in step (5) to LB medium (liquid) and culture for 2-3 days at a temperature of 37℃ and 180 rpm.

[0069] (7) Glycerin for bacterial preservation: Use glycerin with a final concentration of 30% for storage and keep at -80℃;

[0070] (8) Submit samples for identification to determine the strain name;

[0071] (9) Plate transparent ring re-screening: Prepare cellulase qualitative plates, xylanase qualitative plates, mannanase qualitative plates, pectinase qualitative plates and amylase qualitative plates at pH 7 for re-screening, and select the best four bacteria, namely Bacillus licheniformis, Bacillus pumilus, Bacillus subtilis and Bacillus cereus, to form a biological swelling agent.

[0072] Determination of the microbial composition in biological antimicrobial agents;

[0073] (1) Obtaining the source of bacteria: Collect straw decomposition and cultivated soil samples, and soak them in 0.85% physiological saline for 2-3 days to allow the microorganisms in the samples to be fully dispersed in the liquid environment;

[0074] (2) Enrichment culture: Take a certain volume of the bacterial liquid from step (1) and transfer it to LB medium (liquid) for 2-3 days at a temperature of 37℃ and 180 rpm.

[0075] (3) Dilution and spreading: After serial dilution, take 200 μL of the diluted bacterial solution and spread it evenly on LB medium (solid). Incubate for 1-2 days at 37℃.

[0076] (4) Liquid transfer: Select a single colony of different bacteria and transfer it to LB medium (liquid). Incubate for 2-3 days at 55℃ and 180 rpm.

[0077] (5) Streak purification: Streak the bacterial solution from step (4) onto LB medium (solid) and incubate for 1-2 days at a temperature of 55°C;

[0078] (6) Liquid expansion: Transfer the single colony purified and cultured in step (5) to LB medium (liquid) and culture for 2-3 days at a temperature of 37℃ and 180 rpm.

[0079] (7) Glycerin for bacterial preservation: Use glycerin with a final concentration of 30% for storage and keep at -80℃;

[0080] (8) Submit samples for identification to determine the strain name;

[0081] (9) Plate transparent ring re-screening: Prepare cellulase qualitative plates, xylanase qualitative plates, mannanase qualitative plates and amylase qualitative plates at pH 7 respectively for re-screening, and select the best two bacteria, Bacillus licheniformis and Bacillus subtilis, to form a biological antimicrobial agent.

[0082] For any steps not described in detail above, they shall be performed in accordance with conventional practices in the field. After determining the bacterial composition of the bio-swelling and bio-anti-lactation agents, this invention uses existing bacterial strains of the same genus to form a composite microbial pretreatment agent for straw pulping biological pretreatment. The pulping effect is good, indicating that the existing bacterial strains selected in this invention can also achieve the corresponding technical effects. The bacterial strains used in the embodiments of this invention are: Bacillus licheniformis strain number: CICC10086; Bacillus pumilus strain number: CICC 22395; Bacillus subtilis strain number: CICC 10028; Bacillus cereus strain number: CICC 10184; Bacillus licheniformis strain number: CICC 10084; Bacillus subtilis subsp. subtilis strain number: CICC 10085; all purchased from the China Industrial Microbial Culture Collection Center.

[0083] Example 2

[0084] A biological swelling agent for straw pulping, the preparation method of which includes the following steps:

[0085] (1) Activation of strains: Bacillus licheniformis CICC 10086, Bacillus pumilus CICC 22395, Bacillus subtilis CICC 10028 and Bacillus cereus CICC 10184 were inoculated into LB liquid medium and activated at 37°C and 180 rpm for 1 day.

[0086] (2) Bacterial culture: The activated bacterial culture from step (1) was transferred to LB liquid medium, with an inoculum volume of 10% of the medium volume. The culture was expanded at 37°C and 180 rpm for 1 day. The viable count of the resulting Bacillus licheniformis culture was 3.0 × 10⁻⁶. 9 The cfu / mL concentration of Bacillus pumilus was 3.0 × 10⁻⁶. 9 The cfu / mL concentration of Bacillus subtilis in the bacterial suspension was 2.0 × 10⁻⁶. 9 cfu /

[0087] mL, the viable count of Bacillus cereus bacterial suspension was 4.0 × 10⁻⁶. 9 cfu / mL;

[0088] (3) Compounding: The expanded culture of Bacillus licheniformis, Bacillus pumilus, Bacillus subtilis and Bacillus cereus were compounded in a mass ratio of 2:2:2:2 to obtain a biological swelling agent.

[0089] A biological antimicrobial agent for straw pulping, the preparation method of which includes the following steps:

[0090] (1) Activation of strains: Bacillus licheniformis CICC 10084 and Bacillus subtilis subtilis CICC 10085 were inoculated into LB liquid medium and activated at 37°C and 180 rpm for 1 day;

[0091] (2) Bacterial culture: The activated bacterial culture from step (1) was transferred to LB liquid medium, with an inoculum volume of 10% of the medium volume. The culture was expanded at 37°C and 180 rpm for 1 day. The viable count of the resulting Bacillus licheniformis culture was 3.0 × 10⁻⁶. 9 The cfu / mL count of Bacillus subtilis subtilis culture was 2.0 × 10⁻⁶. 9 cfu / mL;

[0092] (3) Compounding: The expanded culture of Bacillus licheniformis and Bacillus subtilis subtilis were compounded at a mass ratio of 1:1 to obtain a biological antimicrobial agent.

[0093] The bio-swelling agent and bio-anti-vaporizing agent prepared above are applied to the production of straw cellulose pulp board and linerboard. The production process is as follows: Figure 1 As shown, the specific steps are as follows:

[0094] (1) Extrusion and washing: The straw is extruded using a screw extruder, and the treated straw is washed to remove impurities. After washing, it is dried.

[0095] (2) Bio-swelling: Transfer the dried straw to a swelling tank, add LB medium, and immerse the straw completely in the medium. Then add 10% of the volume of the medium with bio-swelling agent, mix well, and soak for 2 days.

[0096] (3) Mechanical grinding: The swollen straw is mixed with water at a volume ratio of 1:4 and then processed by a high-consistency grinding machine to obtain bio-swollen coarse pulp;

[0097] (4) Biological defoaming: Add 10% by volume of biological defoaming agent to the biologically swollen coarse slurry, and keep it in a 55℃ water bath for 6 hours to carry out biological defoaming;

[0098] (5) Screening and beating: Transfer the pulp after biological defoaming to a screening machine, collect fibers that meet the papermaking conditions, and put them into a beating machine for beating. Stop beating when the degree of beating is 40±2°SR to obtain straw papermaking pulp;

[0099] (6) Making straw pulp boards: The straw pulp is processed by a pulp board machine to obtain straw pulp boards, and the mass concentration of the straw pulp on the wire is 1.5%;

[0100] (7) Slurry plate swelling: Place the oven-dry slurry plate in a swelling tank, add LB medium, and immerse the slurry plate completely in the medium. Then add 10% of the volume of the medium with biological swelling agent, mix evenly, and soak for 2 days to swell. After filtration, the biological pretreated slurry is obtained.

[0101] (8) Pulping and papermaking: The pretreated biological pulp is fed into a pulper for pulping. Pulping is stopped when the freeness is 78±2°SR. After being treated by a fiber dissociator, the pulp is formed by a papermaking machine to obtain linerboard. The basis weight of the paper is 100 g / m³. 2 .

[0102] Example 3

[0103] A biological swelling agent for straw pulping, the preparation method of which includes the following steps:

[0104] (1) Activation of strains: Bacillus licheniformis CICC 10086, Bacillus pumilus CICC 22395, Bacillus subtilis CICC 10028 and Bacillus cereus CICC 10184 were inoculated into LB liquid medium and activated at 37°C and 180 rpm for 1 day.

[0105] (2) Bacterial culture: The activated bacterial culture from step (1) was transferred to LB liquid medium, with an inoculum volume of 10% of the medium volume. The culture was expanded at 37°C and 180 rpm for 1 day. The viable count of the resulting Bacillus licheniformis culture was 3.0 × 10⁻⁶. 9 The cfu / mL concentration of Bacillus pumilus was 3.0 × 10⁻⁶. 9 The cfu / mL concentration of Bacillus subtilis in the bacterial suspension was 2.0 × 10⁻⁶. 9 The cfu / mL concentration of Bacillus cereus was 4.0 × 10⁻⁶. 9 cfu / mL;

[0106] (3) Compounding: The expanded culture of Bacillus licheniformis, Bacillus pumilus, Bacillus subtilis and Bacillus cereus were compounded in a mass ratio of 3:2:3:1 to obtain the biological swelling agent.

[0107] A biological antimicrobial agent for straw pulping, the preparation method of which includes the following steps:

[0108] (1) Activation of strains: Bacillus licheniformis CICC 10084 and Bacillus subtilis subtilis CICC 10085 were inoculated into LB liquid medium and activated at 37°C and 180 rpm for 1 day;

[0109] (2) Bacterial culture: The activated bacterial culture from step (1) was transferred to LB liquid medium, with an inoculum volume of 10% of the medium volume. The culture was expanded at 37°C and 180 rpm for 1 day. The viable count of the resulting Bacillus licheniformis culture was 3.0 × 10⁻⁶. 9 The cfu / mL count of Bacillus subtilis subtilis culture was 2.0 × 10⁻⁶. 9 cfu / mL;

[0110] (3) Compounding: The expanded culture of Bacillus licheniformis and Bacillus subtilis subtilis were compounded at a mass ratio of 1:1 to obtain a biological antimicrobial agent.

[0111] The bio-swelling agent and bio-anti-vaporizing agent prepared above are applied to the production of straw cellulose pulp board and linerboard. The production process is as follows: Figure 1 As shown, the specific steps are as follows:

[0112] (1) Extrusion and washing: The straw is extruded using a screw extruder, and the treated straw is washed to remove impurities. After washing, it is dried.

[0113] (2) Bio-swelling: Transfer the dried straw to a swelling tank, add LB medium, and immerse the straw completely in the medium. Then add 10% of the culture medium volume of bio-swelling agent, mix well, and soak for 2 days.

[0114] (3) Mechanical grinding: The swollen straw is mixed with water at a volume ratio of 1:4 and then processed by a high-consistency grinding machine to obtain bio-swollen coarse pulp;

[0115] (4) Biological anti-potential agent: Add 10% by volume of biological anti-potential agent to the biologically swelled crude slurry and keep it in a water bath at 55℃ for 6 hours;

[0116] (5) Screening and beating: Transfer the pulp after biological defoaming to a screening machine, collect fibers that meet the papermaking conditions, and put them into a beating machine for beating. Stop beating when the degree of beating is 40±2°SR to obtain straw papermaking pulp;

[0117] (6) Making straw pulp boards: The straw pulp is processed by a pulp board machine to obtain straw pulp boards, and the concentration of the straw pulp at the online feed is 1.5%;

[0118] (7) Slurry plate swelling: Place the oven-dry slurry plate in a swelling tank, add LB medium, and immerse the slurry plate completely in the medium. Then add 10% of the volume of the medium with biological swelling agent, mix evenly, and soak for 2 days to swell. After filtration, the biological pretreated slurry is obtained.

[0119] (8) Pulping and papermaking: The pretreated biological pulp is fed into a pulper for pulping. Pulping is stopped when the freeness is 78±2°SR. After being treated by a fiber dissociator, the pulp is formed by a papermaking machine to obtain linerboard. The basis weight of the paper is 100 g / m³. 2 .

[0120] Comparative Example 1

[0121] The specific steps for preparing straw cellulose pulp boards and boxboards using the alkaline impregnation and swelling method are as follows:

[0122] (1) Extrusion and washing: The straw is extruded using a screw extruder, and the treated straw is washed to remove impurities. After washing, it is dried.

[0123] (2) Alkali soaking and swelling: Transfer the washed straw to the swelling tank, add water to soak it, and it is advisable to soak the straw completely in the water. Then add sodium hydroxide, the amount of sodium hydroxide added is 5% of the dry weight of the straw, mix evenly, and soak for 2 days.

[0124] (3) Mechanical grinding: Mix the swollen straw with water at a volume ratio of 1:4, and then process it with a high-consistency grinding machine to obtain straw coarse pulp;

[0125] (4) Hot water bath for desulfurization: Keep the coarse pulp in an 80℃ water bath for 2 hours;

[0126] (5) Screening and beating: Transfer the pulp after hot water bath desulfurization to the screening machine, collect the fibers that meet the papermaking conditions, and put them into the beating machine for beating. Stop beating when the beating degree is 40±2°SR to obtain straw papermaking pulp;

[0127] (6) Making straw pulp boards: The straw pulp is processed by a pulp board machine to obtain straw pulp boards, and the concentration of the straw pulp at the online feed is 1.5%;

[0128] (7) Swelling of pulp board: Place the dry pulp board in the swelling tank, add water to soak it, and make sure that the pulp board is completely soaked in water. Mix evenly and let it swell for 2 days.

[0129] (8) Pulping and papermaking: The swollen pulp is fed into a pulper for pulping. Pulping is stopped when the freeness is 78±2°SR. After being treated by a fiber desorber, the pulp is formed by a papermaking machine to obtain linerboard. The basis weight of the paper is 100g / m³. 2 .

[0130] Comparative Example 2

[0131] The preparation of straw cellulose pulp board and linerboard using the water immersion swelling method is as follows:

[0132] (1) Extrusion and washing: The straw is extruded using a screw extruder, and the treated straw is washed to remove impurities. After washing, it is dried.

[0133] (2) Soaking and swelling: Transfer the washed straw to the swelling tank, add water to soak it, and make sure that the straw is completely soaked in water. Mix it evenly and let it swell for 2 days.

[0134] (3) Mechanical grinding: Mix the swollen straw with water at a volume ratio of 1:4, and then process it with a high-consistency grinding machine to obtain straw coarse pulp;

[0135] (4) Hot water bath for desulfurization: Keep the coarse pulp in an 80℃ water bath for 2 hours;

[0136] (5) Screening and beating: Transfer the pulp after hot water bath desulfurization to the screening machine, collect the fibers that meet the papermaking conditions, and put them into the beating machine for beating. Stop beating when the beating degree is 40±2°SR to obtain straw papermaking pulp;

[0137] (6) Making straw pulp boards: The straw pulp is processed by a pulp board machine to obtain straw pulp boards, and the concentration of the straw pulp at the feed is 1.5%;

[0138] (7) Swelling of pulp board: Place the dry pulp board in the swelling tank, add water to soak it, and make sure that the pulp board is completely soaked in water. Mix evenly and let it swell for 2 days.

[0139] (8) Pulping and papermaking: The swollen pulp is fed into a pulper for pulping. Pulping is stopped when the freeness is 78±2°SR. After being treated by a fiber desorber, the pulp is formed by a papermaking machine to obtain linerboard. The basis weight of the paper is 100g / m³. 2 .

[0140] Comparative Example 3

[0141] The difference from Example 2 is that the Bacillus subtilis in the bio-swelling agent is CICC 20607, while all other aspects are the same.

[0142] Comparative Example 4

[0143] The difference from Example 2 is that the Bacillus licheniformis in the bio-swelling agent is CICC 10101, while all other aspects are the same.

[0144] Comparative Example 5

[0145] The difference from Example 2 is that the Bacillus pumilus in the bio-swelling agent is CICC 20730, while all other aspects are the same.

[0146] Comparative Example 6

[0147] The difference from Example 2 is that the Bacillus cereus in the biological swelling agent is CICC 10185, while all other aspects are the same.

[0148] Comparative Example 7

[0149] The difference from Example 2 is that the Bacillus licheniformis in the biological disinfectant is CICC 10037, while all other aspects are the same.

[0150] Comparative Example 8

[0151] The difference from Example 2 is that the Bacillus subtilis subsp. subtilis in the biological antimicrobial agent is CICC10073, while all other aspects are the same.

[0152] Example of effect

[0153] The straw pulp and paper obtained in the embodiments and comparative examples of the present invention were tested for pulp yield, whiteness, tensile strength, ring crush, tear strength and bursting strength index of the paper.

[0154] The formula for calculating pulp yield is: Pulp yield (%) = m1 / m, where m1 is the dry weight of straw pulp and m is the dry weight of raw material;

[0155] Whiteness, as well as the tensile strength, ring crush, tear strength, and bursting strength index of the paper, were tested using a whiteness meter, a horizontal paper tensile strength tester, a ring crush strength tester, a tear strength tester, and a horizontal paper tensile strength tester, respectively. The test results are shown in Table 1 below.

[0156] Table 1. Properties of pulp and paper obtained from embodiments and comparative examples of the present invention

[0157]

[0158] As can be seen from Examples 2-3, the biological swelling-inducing agent and biological scavenging agent provided by the present invention, when used for biological treatment of straw, result in paper pulp with a yield higher than 50%, paper brightness higher than 30%, tensile index greater than 24.50 N·m / g, ring crush index greater than 10.50 N·m / g, and tear index greater than 1.10 mN·m. 2 / g, burst strength index greater than 3.00 kPa·m 2 / g, with good results. This indicates that the bio-swelling bacteria agent and bio-anti-vaporization pulping method provided by this invention meet the requirements in terms of pulp yield and brightness, and the mechanical properties of the produced paper are also excellent.

[0159] As can be seen from Comparative Example 1, by comparing the microbial treatment mechanical pulping method of the present invention (Example 2), the pulp and paper properties obtained by chemical swelling and hot water de-swelling are lower than those obtained by biological swelling and biological de-swelling, and the use of a large number of chemical agents is avoided, which has excellent characteristics of being green, non-toxic and biodegradable.

[0160] As shown in Comparative Example 2, by comparing the microbial treatment mechanical pulping method of the present invention (Example 2), the pulp and paper properties obtained by traditional water swelling and hot water de-emulsification are lower than those obtained by biological swelling and biological de-emulsification, and the service life of the equipment can be improved. Figure 2 This is a comparison diagram of the paper prepared in Example 2 and Comparative Example 2. Figure 2 The results show that the paper treated with microorganisms is significantly less rough than the untreated paper, and its whiteness is significantly higher than that of the untreated paper.

[0161] As can be seen from Comparative Examples 3-8, changing the types of bacteria in the biological swelling agent and the biological anti-potential agent will weaken the synergistic effect of each bacteria. The resulting pulp and paper properties are lower than those after treatment with the bacteria in the technical solution of this invention, and the pulping effect of straw deteriorates.

[0162] The dosage of the biological swelling agent and biological anti-fouling agent of this invention is based on a comprehensive consideration of the use and degradation efficiency of the agents. It was found that the dosage within the above range can save the amount of agents used, with a moderate treatment time and a suitable degradation effect. Although increasing the dosage can accelerate degradation, the cost is also relatively high.

[0163] The present invention uses a combination of biological swelling agent and biological anti-fouling agent in mechanical pulping and papermaking, resulting in paper pulp with high yield, high paper whiteness, and advantages in tensile index, ring crush index, tear index, and bursting index. The microbial composition of the biological swelling agent and biological anti-fouling agent plays a certain synergistic role, and avoids the use of a large number of chemical agents, thus possessing excellent characteristics of being green, non-toxic, and biodegradable.

Claims

1. The application of biological swelling-inducing agents and biological anti-lactation agents in straw pulping and papermaking, characterized in that, Includes the following steps: I. Compression and Washing: The straw is compressed, washed, and dried for later use; II. Bio-swelling: Transfer the dried straw to a swelling tank, add LB medium, then add bio-swelling agent, mix evenly, and soak for 1-2 days; after draining the straw, add water to the pulping raw material, stir, and then process it through a high-consistency pulping machine for mechanical pulping to obtain bio-swelled coarse pulp. III. Biological defoaming: Add biological defoaming agent to the biologically swelled crude slurry, and keep it in a water bath at 55℃~60℃ for 6h~8h to carry out biological defoaming; IV. Pulping: The pulp after biological defoaming is transferred to a pulp screener to collect fibers that meet the papermaking conditions. The fibers are then laid into a pulp beater for pulping. Pulping is stopped when the freeness is 40±2°SR to obtain straw papermaking pulp. V. Pulpboard: The straw papermaking pulp obtained in step IV is formed into a pulpboard using a pulpboard machine to obtain a pulpboard. The on-grid concentration of the straw papermaking pulp is 1.3% to 2.0%. VI. Slurry plate swelling: Place the oven-dry slurry plate in a swelling tank, add LB medium, then add biological swelling agent, mix evenly, and soak for 1-2 days to swell; after filtration, obtain biological pretreated slurry; VII. Pulping and Papermaking: The pretreated biological pulp is fed into a pulper for pulping. Pulping is stopped at a freeness of 78±2°SR. After treatment by a fiber desorber, the pulp is formed on a paper machine to obtain linerboard with a basis weight of 80 g / m². 2 ~100g / m 2 ; The biological swelling agent is composed of Bacillus licheniformis CICC 10086, Bacillus subtilis CICC 10028, Bacillus pumilus CICC 22395 and Bacillus cereus CICC 10184; The biological disinfectant is composed of Bacillus licheniformis CICC 10086 and Bacillus subtilis subsp. subtilis CICC 10085.

2. The application as described in claim 1, characterized in that, The composition of each bacterial species in the biological swelling agent is as follows: Bacillus licheniformis bacterial solution, Bacillus subtilis bacterial solution, Bacillus pumilus bacterial solution and Bacillus cereus bacterial solution are compounded in a mass ratio of (1~3):(1~3):(1~3):(1~3); The viable count of each bacterial culture solution was 1.0 × 10⁻⁶. 9 cfu / mL ~1.0×10 11 cfu / mL.

3. The application as described in claim 1, characterized in that, The preparation method of the biological swelling agent includes the following steps: (1) Activation of bacterial strains: Take the target bacterial strains and inoculate them into liquid culture medium for activation culture; (2) Expanding the compounding: The activated target strain is expanded in liquid culture medium, and the expanded culture liquid is mixed and compounded in proportion to obtain the biological swelling agent.

4. The application as described in claim 3, characterized in that, In steps (1) and (2), the liquid culture medium is LB liquid culture medium; In step (1), the culture conditions are 35~40℃ and 150~200rpm for 1~2 days; In step (2), the culture conditions are 35~40℃ and 150~200rpm for 2~4 days.

5. The application as described in claim 1, characterized in that, The composition of each bacterial species in the biological antimicrobial agent is as follows: Bacillus licheniformis bacterial solution and Bacillus subtilis subtilis bacterial solution are compounded in a mass ratio of (1~3):(1~3); The viable count of each bacterial culture solution was 1.0 × 10⁻⁶. 9 cfu / mL ~1.0×10 11 cfu / mL.

6. The application as described in claim 1, characterized in that, The preparation method of the biological antimicrobial agent includes the following steps: ① Activation of bacterial strains: Take the target bacterial strains and inoculate them into liquid culture medium for activation culture; ② Expanded compounding: The activated target strain is cultured in liquid culture medium, and the cultured bacterial solutions are mixed and compounded in proportion to obtain the biological antimicrobial agent.

7. The application as described in claim 6, characterized in that, In both steps ① and ②, the liquid culture medium is LB liquid culture medium; In step ①, the culture conditions are 35~40℃ and 150~200rpm for 1~2 days; In step ②, the culture conditions are 35~40℃ and 150~200rpm for 2~4 days.

8. The application as described in claim 1, characterized in that, In step II, the amount of the biological swelling agent added is 10% to 15% of the liquid volume.

9. The application as described in claim 1, characterized in that, In step II, the swelling conditions are 30~40℃ for 2~4 days.

10. The application as described in claim 9, characterized in that, In step II, the swelling condition is 37°C for 2-3 days.

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