Preparation process of chemi-mechanical pulp

Abstract

The invention provides a preparation process of chemi-mechanical pulp, which comprises the following steps: S100, pretreating plant fibers to obtain raw material fibers; s200, performing soaking treatment on the raw material fibers by adopting a chemical treatment agent and a biological enzyme treatment agent to obtain softened fibers; and S300, feeding the softened fibers and the filler into a disc mill for disc milling and pulping to obtain the chemimechanical pulp, wherein the chemical treatment agent comprises sodium percarbonate, alkyl sodium sulfonate, sodium hydroxide, urea, sodium silicate, sodium sulfate and aluminum phosphate; the biological enzyme treatment agent is prepared from xylanase, cellulase, pectinase, laccase and citric acid; the filler comprises triethyl phosphate, a molecular sieve and silicon dioxide. The invention provides a technical scheme for improving the fireproof and heat-resistant performance of a paper product through a chemical-mechanical pulping process.

Description

Technical Field

[0001] The present invention relates to the technical field of papermaking, and in particular to a process for preparing chemical-mechanical pulp. Background Art

[0002] Paper products such as packaging paperboard and corrugated paper have broad market prospects in the packaging field. Paper products such as packaging paperboard and corrugated paper are usually obtained through chemical mechanical pulping, papermaking, drying, calendering and other processes.

[0003] Chemimechanical pulping is a pulping method that uses chemical pretreatment and mechanical grinding post-treatment. First, a mild pretreatment (impregnation or cooking) is performed with chemicals to remove some hemicellulose in the wood chips, and the lignin is less dissolved or basically not dissolved, but the intercellular layer is softened. Then, the wood chips (or straw chips) are ground and softened by a disc refiner to separate the fibers into pulp, which is referred to as chemimechanical pulp (CMP).

[0004] The chemical pretreatment of chemimechanical pulp is much milder than the cooking process of chemical pulping. It has less delignification effect on the raw materials and less damage to cellulose. Only hemicellulose with lower molecular weight is dissolved. Therefore, the chemimechanical pulp produced generally contains higher lignin and cellulose components and lower hemicellulose components.

[0005] The physical strength of this pulp is between chemical pulp and mechanical pulp, which can make the finished paper have very good stiffness. Its bleaching, hydration and drainage properties are relatively close to those of mechanical pulp.

[0006] The shortcomings of the existing technologies related to paper products such as packaging paperboard and corrugated paper are that their fire and heat resistance properties need to be improved. Summary of the invention

[0007] The present invention aims to solve at least one of the above-mentioned technical problems and provides a technical solution for improving the fire and heat resistance of paper products by improving the chemical mechanical pulping process.

[0008] In order to achieve the above-mentioned object of the present invention, the present invention provides a process for preparing chemical mechanical pulp, the preparation process comprising:

[0009] S100, pretreating plant fibers to obtain raw fiber;

[0010] S200, soaking the raw fiber with a chemical treatment agent and a biological enzyme treatment agent to obtain softened fiber;

[0011] S300, sending the softened fiber and filler into a disc refiner for disc refinement and beating to obtain the chemical mechanical pulp;

[0012] The chemical treatment agent includes sodium percarbonate, sodium alkyl sulfonate, sodium hydroxide, urea, sodium silicate, sodium sulfate, and aluminum phosphate; the biological enzyme treatment agent includes xylanase, cellulase, pectinase, laccase, and citric acid; and the filler includes triethyl phosphate, molecular sieve, and silicon dioxide.

[0013] In any of the above technical solutions, the total added amount of the plant fiber is divided into 100 parts by mass, and the plant fiber in S100 includes: coniferous tree fiber, 40 parts by mass to 50 parts by mass; broad-leaved tree fiber, 30 parts by mass to 40 parts by mass; corn straw fiber, 15 parts by mass to 20 parts by mass.

[0014] In any of the above technical solutions, the pretreatment in S100 specifically includes: cutting, crushing, screening and washing.

[0015] In any of the above technical solutions, the total added amount of the chemical treatment agent is divided into 100 parts by mass, and the chemical treatment agent includes: sodium percarbonate, 30 to 35 parts by mass; sodium alkyl sulfonate, 20 to 25 parts by mass; sodium hydroxide, 15 to 20 parts by mass; urea, 15 to 20 parts by mass; sodium silicate, 4 to 6 parts by mass; sodium sulfate, 2 to 4 parts by mass; aluminum phosphate, 1 to 2 parts by mass.

[0016] In any of the above technical solutions, the total added amount of the biological enzyme treatment agent is divided into 100 parts by mass, and the biological enzyme treatment agent includes: xylanase, 26 to 30 parts by mass; cellulase, 24 to 28 parts by mass; pectinase, 18 to 20 parts by mass; laccase, 12 to 16 parts by mass; citric acid, 12 to 16 parts by mass.

[0017] In any of the above technical solutions, in S200, the mass ratio of chemical treatment agent: biological enzyme treatment agent: raw fiber: water = (0.08-0.1): (0.02-0.04): (12-16): 100.

[0018] In any of the above technical solutions, in S200, the temperature of the immersion treatment is 48° C. to 50° C., and the time of the immersion treatment is 2 h to 2.5 h.

[0019] In any of the above technical solutions, in S300, the mass ratio is softened fiber: filler = 100: (4-8).

[0020] In any of the above technical solutions, in S300, the pulping concentration of the disc refiner is 18% to 22%, and the beating degree of the chemical mechanical pulp is 35°SR to 45°SR.

[0021] In any of the above technical solutions, the filler is prepared by the following steps:

[0022] S410, uniformly mixing the triethyl phosphate, the molecular sieve, the ethyl silicate, the ethanol and the water in a mass ratio of triethyl phosphate: molecular sieve: ethyl silicate: ethanol: water = (2-4): (4-6): (15-25): (30-40): 100, dropping an acid to adjust the pH value to 4-5, stirring the reaction for 2h to 3h, and obtaining a silicate sol;

[0023] S420, adding alkali to the silicate sol to adjust the pH value to 10 to 11, leaving it to stand for 12 to 14 hours, then taking it out, and immersing it in anhydrous ethanol to age it for 24 to 30 hours, to obtain a silica gel containing the triethyl phosphate and the molecular sieve;

[0024] S430, feeding the sodium 2-chloroethyl sulfonate and the silica gel into a reaction kettle at a mass ratio of sodium 2-chloroethyl sulfonate: silica gel = (2-4): 100, and performing a hydrothermal treatment for 2 h to 2.5 h at a temperature of 170° C. to 180° C. and a pressure of 1.5 MPa to 2.5 MPa;

[0025] S440, after the hydrothermal treatment is completed, the temperature is lowered and the pressure is released, the solid matter is filtered, washed, and dried to obtain the filler.

[0026] After adopting the technical solution of the present invention, the technical effects that can be achieved are as follows:

[0027] The present invention provides a preparation process of chemical mechanical pulp, which first pre-treats plant fibers to obtain raw fiber; then soaks the raw fiber with chemical treatment agent and biological enzyme treatment agent to obtain softened fiber; finally, feeds the softened fiber and filler into a disc grinder for disc grinding and pulping to obtain the chemical mechanical pulp. The function of the chemical treatment agent is to destroy the fiber structure of the plant fiber. Among them, the chemical treatment agent includes: sodium percarbonate, sodium alkyl sulfonate, sodium hydroxide, urea, sodium silicate, sodium sulfate, and aluminum phosphate. The biological enzyme treatment agent includes: xylanase, cellulase, pectinase, laccase, and citric acid. The filler includes: triethyl phosphate, molecular sieve and silicon dioxide. Triethyl phosphate is used as a flame retardant and carbonization promoter, molecular sieve can be used as an adsorbent and heat stabilizer, and the melting point of silicon dioxide is about 1700°C, which can be used as an inert skeleton reinforcement material to resist high temperature deformation. The invention utilizes triethyl phosphate to inhibit combustion, molecular sieve to absorb and decompose gas, and silicon dioxide to provide heat insulation and structural support, thereby forming a multi-layer fire-resistant and flame-retardant protection. DETAILED DESCRIPTION

[0028] In order to more clearly understand the above-mentioned purpose, features and advantages of the present invention, the present invention is further described in detail below in conjunction with specific embodiments. It should be noted that the embodiments of the present application and the features in the embodiments can be combined with each other without conflict.

[0029] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Therefore, the protection scope of the present invention is not limited to the specific embodiments disclosed below.

[0030] In order to make the above-mentioned purposes, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below.

[0031] The present invention provides a process for preparing chemical mechanical pulp, the process comprising:

[0032] S100, pretreating plant fibers to obtain raw fiber;

[0033] S200, soaking the raw fiber with a chemical treatment agent and a biological enzyme treatment agent to obtain softened fiber;

[0034] S300, sending the softened fibers and fillers into a disc refiner for disc refinement and pulping to obtain the chemical mechanical pulp.

[0035] In some embodiments of the present invention, the total added amount of the plant fiber is divided into 100 parts by mass, and the plant fiber in S100 includes: coniferous tree fiber, 40 parts by mass to 50 parts by mass; broad-leaved tree fiber, 30 parts by mass to 40 parts by mass; corn straw fiber, 15 parts by mass to 20 parts by mass.

[0036] Preferably, the total added amount of the plant fibers is divided into 100 parts by mass, and the plant fibers in S100 include: coniferous tree fibers, 45 parts by mass; broadleaf tree fibers, 35 parts by mass; and corn stalk fibers, 20 parts by mass.

[0037] In the papermaking process, softwood fibers and hardwood fibers each have unique roles due to their differences in structure and performance. When used in synergy, paper performance and process economy can be optimized through complementarity. Softwood fibers (such as pine and fir) are generally 2-4 mm in length, with a high aspect ratio, thick fiber cell walls, and excellent mechanical strength (tensile strength, tear strength). Long fibers are easy to form a three-dimensional network structure, providing skeleton support to improve the tensile strength, bursting resistance and tear resistance of the finished paper, and are suitable for high-strength paper types such as packaging paper and paper bag paper. Hardwood fibers (such as eucalyptus and poplar) are generally 0-1.5 mm in length, short and thin. The fiber surface is smooth, the cell wall is thin, and it is easy to be crushed. Short fibers can fill the gaps between long fibers to form a dense structure. Short fibers are easier to pulp, reducing the energy consumption of pulping (the energy consumption required to beat hardwood fibers to the same freeness is lower than that of softwood). Coniferous wood fibers provide skeleton support, while broadleaf wood fibers fill the surface, making the paper have both high strength (such as tensile strength) and good flexibility (such as folding resistance). Broadleaf wood fibers improve smoothness, while coniferous wood fibers reduce hair loss and powder loss. Straw is an agricultural waste that is abundant and renewable. It can reduce dependence on wood and is especially suitable for areas with scarce forest resources. The cost of obtaining straw is lower than that of wood, making it suitable for the production of low value-added paper types (such as corrugated paper and packaging paper). Straw fibers are shorter (0.5-1.5 mm), similar to broadleaf wood fibers, and can fill the gaps between long fibers to improve the tightness and smoothness of paper. Straw fibers are completely degradable and suitable for the production of environmentally friendly packaging materials or disposable paper products.

[0038] In some embodiments of the present invention, the pretreatment in S100 specifically includes: cutting, crushing, screening and washing.

[0039] In some embodiments of the present invention, in S200, by mass ratio, chemical treatment agent: biological enzyme treatment agent: raw fiber: water = (0.08-0.1): (0.02-0.04): (12-16): 100. Preferably, in S200, by mass ratio, chemical treatment agent: biological enzyme treatment agent: raw fiber: water = 0.08: 0.04: 14: 100. In some embodiments of the present invention, in S200, the temperature of the soaking treatment is 48° C. to 50° C., and the time of the soaking treatment is 2 h to 2.5 h.

[0040] In some embodiments of the present invention, in S300, the mass ratio of softened fiber:filler=100:(4-8). The pulping concentration of the disc refiner is 18% to 22%, and the beating degree of the chemical mechanical pulp is 35°SR to 45°SR.

[0041] The chemical treatment agent includes sodium percarbonate, sodium alkyl sulfonate, sodium hydroxide, urea, sodium silicate, sodium sulfate, and aluminum phosphate; the biological enzyme treatment agent includes xylanase, cellulase, pectinase, laccase, and citric acid; and the filler includes triethyl phosphate, molecular sieve, and silicon dioxide.

[0042] In some embodiments of the present invention, the total added amount of the chemical treatment agent is divided into 100 parts by mass, and the chemical treatment agent includes: sodium percarbonate, 30 to 35 parts by mass; sodium alkyl sulfonate, 20 to 25 parts by mass; sodium hydroxide, 15 to 20 parts by mass; urea, 15 to 20 parts by mass; sodium silicate, 4 to 6 parts by mass; sodium sulfate, 2 to 4 parts by mass; aluminum phosphate, 1 to 2 parts by mass.

[0043] Preferably, the total added amount of the chemical treatment agent is divided into 100 parts by mass, and the chemical treatment agent includes: sodium percarbonate, 35 parts by mass; sodium alkyl sulfonate, 20 parts by mass; sodium hydroxide, up to 20 parts by mass; urea, 15 parts by mass; sodium silicate, 5 parts by mass; sodium sulfate, 4 parts by mass; and aluminum phosphate, 1 part by mass.

[0044] Sodium percarbonate acts as an oxidant and bleaching agent, releasing hydrogen peroxide (H 2 O 2 ) and sodium carbonate, thereby oxidizing the chromophores in lignin, improving the whiteness of the pulp, and destroying the combination of lignin and cellulose, assisting in fiber separation. The present invention replaces traditional chlorine-based bleaching agents with sodium percarbonate, which can achieve mild oxidation and reduce fiber damage. Sodium alkyl sulfonate (Sodium Alkyl Sulfonate) is used as a surfactant and wetting agent, which can reduce the surface tension of the liquid, promote the penetration of chemicals into the interior of the wood chips, and also promote fiber dispersion, prevent agglomeration, and improve the uniformity of subsequent mechanical treatment. Sodium hydroxide (Sodium Hydroxide) is a strong alkali and is the core reagent required for lignin removal. Sodium hydroxide can saponify the ester bonds and ether bonds in lignin, destroy its three-dimensional structure, and swell the fiber cell wall, soften the raw material, and reduce the energy consumption of mechanical pulping. Urea (Urea) can be used as a fiber swelling promoter and reaction aid, which synergistically acts with alkali to enhance the dissolution of lignin and hemicellulose. In addition, urea decomposes at high temperatures to generate ammonia (NH 3), which can adjust the local pH and optimize the reaction conditions. Sodium silicate (Sodium Silicate, water glass) is used as a pH buffer and dispersant. It can stabilize the alkaline environment and prevent fiber degradation caused by drastic pH fluctuations. It can also be adsorbed on the fiber surface to reduce scaling and improve slurry uniformity. The role of sodium sulfate is to promote the penetration efficiency of chemicals. Aluminum phosphate (Aluminum Phosphate) is adsorbed on the fiber surface to improve the slurry filterability and physical properties of paper. The above raw materials cooperate with each other and work synergistically to destroy the lignin structure and promote chemical penetration and fiber dispersion.

[0045] In some embodiments of the present invention, the total addition amount of the biological enzyme treatment agent is divided into 100 parts by mass, and the biological enzyme treatment agent includes: xylanase, 26 to 30 parts by mass; cellulase, 24 to 28 parts by mass; pectinase, 18 to 20 parts by mass; laccase, 12 to 16 parts by mass; citric acid, 12 to 16 parts by mass.

[0046] Preferably, the total added amount of the biological enzyme treatment agent is divided into 100 parts by mass, and the biological enzyme treatment agent includes: xylanase, 30 parts by mass; cellulase, 25 parts by mass; pectinase, 20 parts by mass; laccase, 12.5 parts by mass; and citric acid, 12.5 parts by mass.

[0047] Biological enzymes can achieve efficient and low-energy fiber separation by selectively degrading specific components of plant cell walls (such as lignin, hemicellulose, pectin, etc.) and assisting chemical or mechanical treatment. Xylanase, as a hemicellulose degrader, specifically hydrolyzes the xylan main chain in hemicellulose, destroys the cross-linking structure between hemicellulose, lignin and cellulose, and can also release the pores on the fiber surface to promote the subsequent penetration of chemicals (such as alkali) and lignin removal. Xylanase can reduce the amount of chemical reagents, reduce the risk of fiber damage, and increase the pulp yield. Cellulase, as a cellulose surface modifier, partially hydrolyzes the amorphous region of cellulose or the fiber surface, weakens the hydrogen bonding force between fibers, and improves fiber flexibility and paper strength. Cellulase and xylanase are used together to synergistically optimize the fiber separation effect. Pectinase is a pectin decomposition and fiber separation promoter that degrades pectin in the middle layer and primary wall of plant cells and removes the adhesive effect between fiber bundles. Pectinase is particularly suitable for non-wood raw materials (such as hemp and straw) to promote the dispersion of their fibers. Pectinase can reduce the energy consumption of mechanical processing and reduce fiber breakage. Laccase is an oxidative degradation enzyme for lignin. It oxidizes the phenolic structure of lignin in the presence of oxygen and destroys its aromatic ring network. Laccase can delignify under mild conditions and reduce the amount of chemicals used (such as replacing part of the alkaline treatment). Citric acid is used as a pH regulator to adjust the pH value of the reaction system to the optimal activity range of the biological enzyme (such as xylanase and laccase usually work under weakly acidic to neutral conditions).

[0048] The filler includes: triethyl phosphate, molecular sieve and silicon dioxide. Triethyl phosphate (TEP) is used as a flame retardant and carbonization promoter. It decomposes at high temperature to generate phosphoric acid and phosphoric acid derivatives, captures free radicals (such as ·OH, ·H) in the combustion chain reaction, inhibits flame propagation, and promotes the formation of a carbon layer (carbonization) on the surface of the material, isolates oxygen and heat, and delays the combustion process. Molecular sieve (Molecular Sieve) can be used as an adsorbent and thermal stabilizer. It absorbs small molecules (such as water vapor, CO) released by combustion through a uniform microporous structure. 2 , acidic gases), reduce the internal thermal stress of the material, and adsorb volatile substances (such as plasticizers and degradation products). The melting point of silicon dioxide is about 1700°C, and it can be used as an inert skeleton to enhance the material's resistance to high-temperature deformation. Silicon dioxide has excellent thermal insulation properties and can further inhibit heat conduction through interface scattering. The present invention uses triethyl phosphate to inhibit combustion, molecular sieves to adsorb decomposition gases, and silicon dioxide to provide thermal insulation and structural support to form a multi-level fire-resistant protection.

[0049] In some embodiments of the present invention, the filler is prepared by the following steps:

[0050] S410, uniformly mixing the triethyl phosphate, the molecular sieve, the ethyl silicate, the ethanol and the water in a mass ratio of triethyl phosphate: molecular sieve: ethyl silicate: ethanol: water = (2-4): (4-6): (15-25): (30-40): 100, dropping an acid to adjust the pH value to 4-5, stirring the reaction for 2h to 3h, and obtaining a silicate sol;

[0051] S420, adding alkali to the silicate sol to adjust the pH value to 10 to 11, leaving it to stand for 12 to 14 hours, then taking it out, and immersing it in anhydrous ethanol to age it for 24 to 30 hours, to obtain a silica gel containing the triethyl phosphate and the molecular sieve;

[0052] S430, feeding the sodium 2-chloroethyl sulfonate and the silica gel into a reaction kettle at a mass ratio of sodium 2-chloroethyl sulfonate: silica gel = (2-4): 100, and performing a hydrothermal treatment for 2 h to 2.5 h at a temperature of 170° C. to 180° C. and a pressure of 1.5 MPa to 2.5 MPa;

[0053] S440, after the hydrothermal treatment is completed, the temperature is lowered and the pressure is released, the solid matter is filtered, washed, and dried to obtain the filler.

[0054] Preferably, the filler is prepared by the following steps:

[0055] S410, uniformly mixing the triethyl phosphate, the molecular sieve, the ethyl silicate, the ethanol and the water in a mass ratio of triethyl phosphate: molecular sieve: ethyl silicate: ethanol: water = 4:4:25:35:100, dropping an acid to adjust the pH value to 4, stirring and reacting for 2.5 hours to obtain a silicate sol;

[0056] S420, adding alkali to the silicate sol to adjust the pH value to 10, taking it out after standing for 12 hours, and immersing it in anhydrous ethanol for aging for 24 hours to obtain a silica gel containing the triethyl phosphate and the molecular sieve;

[0057] S430, feeding the sodium 2-chloroethyl sulfonate and the silica gel into a reaction kettle at a mass ratio of sodium 2-chloroethyl sulfonate to silica gel = 4:100, and performing a hydrothermal treatment for 2 hours at a temperature of 175° C. and a pressure of 1.5 MPa;

[0058] S440, after the hydrothermal treatment is completed, the temperature is lowered and the pressure is released, the solid matter is filtered, washed, and dried to obtain the filler.

[0059] The above steps prepare nano silicon oxide particles by the sol-gel method. The sol-gel method uses ethyl silicate as an organosilicon source and uses acid as a catalyst in a mixture of water and alcohol to form a sol. In the process of forming the silica sol, the present invention adds triethyl phosphate and molecular sieves to make the two uniformly dispersed in the silica sol. Silica gel can be obtained by adding alkali to adjust the pH value and standing and aging in anhydrous ethanol. After the silica gel and sodium 2-chloroethylsulfonate are mixed, the sulfonic acid group-modified nano silicon oxide particles are prepared by a hydrothermal method. The sulfonic acid group (-SO 3 H) Give the nano-silicon oxide surface a strong negative charge, enhance its dispersion stability in the slurry, and reduce agglomeration. The sulfonic acid group forms a hydrogen bond or electrostatic effect with the cellulose hydroxyl group (-OH), promoting the combination of filler and fiber. Therefore, the nano-silicon oxide particles modified by the sulfonic acid group can be used as fillers to improve the mechanical strength and mechanical properties of paper products.

[0060] Example 1

[0061] In this embodiment, a series of chemical treatment agents are prepared. The raw material ratios are shown in Table 1. The preparation process is to mix the raw materials by ball milling and then discharging the materials.

[0062] Table 1

[0063]

[0064] Example 2

[0065] This embodiment prepares a series of biological enzyme treatment agents, and the raw material ratios thereof are shown in Table 2. The preparation process is to stir the raw materials uniformly and then discharge the materials.

[0066] Table 2

[0067] Serial number Xylanase Cellulase Pectinase Laccase Citric Acid Bio-enzyme treatment agent sample 1 30 parts by mass 25 parts by mass 20 parts by mass 12.5 parts by mass 12.5 parts by mass Bio-enzyme treatment agent sample 2 26 parts by mass 24 parts by mass 18 parts by mass 16 parts by mass 16 parts by mass

[0068] Example 3

[0069] This example provides a series of filler samples, the raw material ratios of which are shown in Table 3, and the preparation process is as follows.

[0070] S1, uniformly mixing the triethyl phosphate, the molecular sieve, the ethyl silicate, the ethanol and the water, dropping an acid to adjust the pH value to 4, stirring and reacting for 2.5 hours to obtain a silicate sol;

[0071] S2, adding alkali to the silicate sol to adjust the pH value to 10, taking it out after standing for 12 hours, and immersing it in anhydrous ethanol for aging for 24 hours to obtain a silica gel containing the triethyl phosphate and the molecular sieve;

[0072] S3, sending the sodium 2-chloroethylsulfonate and the silica gel into a reactor, and performing a hydrothermal treatment for 2 hours at a temperature of 175° C. and a pressure of 1.5 MPa;

[0073] S4, after the hydrothermal treatment is completed, the temperature is lowered and the pressure is released, the solid matter is filtered, washed, and dried to obtain the filler.

[0074] Table 3

[0075]

[0076] Example 4

[0077] This example provides a series of paper samples, the raw material ratios of which are shown in Table 4, and the preparation process is as follows.

[0078] S1. Weigh the materials according to the mass ratio of coniferous tree fiber: broadleaf tree fiber: corn straw fiber = 45:35:20, cut them respectively, crush them into target particle size range, screen them, wash them with water, and mix them to obtain raw fiber;

[0079] S2. Prepare a soaking solution according to the mass ratio of chemical treatment agent: biological enzyme treatment agent: raw fiber: water = 0.08:0.04:14:100, soak the raw fiber at a soaking temperature of 48°C for 2 hours to obtain softened fiber;

[0080] S3, sending the softened fiber and the filler into a disc refiner for disc refining and pulping at a mass ratio of softened fiber to filler = 100:6 to obtain a chemical mechanical pulp;

[0081] S4. After preparing the chemical mechanical pulp, a wet strength agent or a wet strength agent and a softener are added, and after mixing evenly, papermaking, dehydration, drying, wrinkling and winding are performed to obtain a paper sample.

[0082] Table 4

[0083]

[0084] Performance Testing

[0085] The performance test results of paper samples 1-4 are shown in Table 5.

[0086] Table 5

[0087] performance Sample 1 Sample 2 Sample 3 Sample 4 Tensile strength (N·m / g) 82 76 78 75 <![CDATA[Tear index (mN m 2 / g)]]> 9.1 7.2 7.8 7.4 Afterburning time(s) 3.8 4.7 5.1 4.0

[0088] In the description of this specification, the description of the terms "one embodiment", "some embodiments", "specific embodiments", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0089] Although the present invention is disclosed as above, the present invention is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the scope defined by the claims.

Claims

1. A process for preparing a chemical mechanical pulp, characterized in that: The preparation process comprises: S100, pretreating plant fibers to obtain raw fiber; S200, soaking the raw fiber with a chemical treatment agent and a biological enzyme treatment agent to obtain softened fiber; S300, sending the softened fiber and filler into a disc refiner for disc refinement and beating to obtain the chemical mechanical pulp; The chemical treatment agent includes sodium percarbonate, sodium alkyl sulfonate, sodium hydroxide, urea, sodium silicate, sodium sulfate, and aluminum phosphate; the biological enzyme treatment agent includes xylanase, cellulase, pectinase, laccase, and citric acid; and the filler includes triethyl phosphate, molecular sieve, and silicon dioxide.

2. The preparation process according to claim 1, characterized in that: Taking the total added amount of the plant fibers as 100 parts by mass, the plant fibers in S100 include: coniferous tree fibers, 40 parts by mass to 50 parts by mass; broadleaf tree fibers, 30 parts by mass to 40 parts by mass; and corn stalk fibers, 15 parts by mass to 20 parts by mass.

3. The preparation process according to claim 1, characterized in that: The pretreatment in S100 specifically includes: cutting, crushing, screening and washing.

4. The preparation process according to claim 1, characterized in that: The total added amount of the chemical treatment agent is divided into 100 parts by mass, and the chemical treatment agent includes: sodium percarbonate, 30 to 35 parts by mass; sodium alkyl sulfonate, 20 to 25 parts by mass; sodium hydroxide, 15 to 20 parts by mass; urea, 15 to 20 parts by mass; sodium silicate, 4 to 6 parts by mass; sodium sulfate, 2 to 4 parts by mass; aluminum phosphate, 1 to 2 parts by mass.

5. The preparation process according to claim 1, characterized in that: The total added amount of the biological enzyme treatment agent is divided into 100 parts by mass, and the biological enzyme treatment agent includes: xylanase, 26 to 30 parts by mass; cellulase, 24 to 28 parts by mass; pectinase, 18 to 20 parts by mass; laccase, 12 to 16 parts by mass; citric acid, 12 to 16 parts by mass.

6. The preparation process according to claim 1, characterized in that: In S200, the mass ratio of chemical treatment agent:biological enzyme treatment agent:raw fiber:water=(0.08-0.1):(0.02-0.04):(12-16):

100.

7. The preparation process according to claim 1, characterized in that: In S200, the temperature of the immersion treatment is 48°C to 50°C, and the time of the immersion treatment is 2h to 2.5h.

8. The preparation process according to claim 1, characterized in that: In S300, the mass ratio of softened fiber:filler=100:(4-8).

9. The preparation process according to claim 1, characterized in that: In S300, the pulping concentration of the disc refiner is 18% to 22%, and the beating degree of the chemical mechanical pulp is 35°SR to 45°SR.

10. The preparation process according to any one of claims 1 to 9, characterized in that: The filler is prepared by the following steps: S410, uniformly mixing the triethyl phosphate, the molecular sieve, the ethyl silicate, the ethanol and the water in a mass ratio of triethyl phosphate: molecular sieve: ethyl silicate: ethanol: water = (2-4): (4-6): (15-25): (30-40): 100, dropping an acid to adjust the pH value to 4-5, stirring the reaction for 2h to 3h, and obtaining a silicate sol; S420, adding alkali to the silicate sol to adjust the pH value to 10 to 11, leaving it to stand for 12 to 14 hours, then taking it out, and immersing it in anhydrous ethanol to age it for 24 to 30 hours, to obtain a silica gel containing the triethyl phosphate and the molecular sieve; S430, feeding the sodium 2-chloroethyl sulfonate and the silica gel into a reaction kettle at a mass ratio of sodium 2-chloroethyl sulfonate: silica gel = (2-4): 100, and performing a hydrothermal treatment for 2 h to 2.5 h at a temperature of 170° C. to 180° C. and a pressure of 1.5 MPa to 2.5 MPa; S440, after the hydrothermal treatment is completed, the temperature is lowered and the pressure is released, the solid matter is filtered, washed, and dried to obtain the filler.

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