Enzymatic pulping process for improving performance of cultural paper and application of enzymatic pulping process

Abstract

The invention provides an enzymatic pulping process for improving the performance of cultural paper and application of the enzymatic pulping process, and belongs to the technical field of papermaking. The pulping process comprises the following steps: S1, mixing an acetic acid / sodium acetate buffer solution and bleached eucalyptus pulp, pouring the mixture into a reaction kettle, and preheating, wherein the reaction temperature is 30-50 DEG C; s2, sub-packaging the preheated bleached eucalyptus pulp in two thermostatic baths, adding endoglucanase into one thermostatic bath, adding xylanase and pectinase into the other thermostatic bath, reacting for a preset time, and inactivating; and S3, taking and mixing the absolutely dry slurry from the two thermostatic baths respectively, and grinding the slurry in a PFI pulping machine. An acetic acid / sodium acetate buffer solution is used for cooperating with enzymes to conduct enzymolysis on fibers, energy consumption is reduced, paper strength is enhanced, acetic acid / sodium acetate can enhance the pretreatment effect of the fibers, the competitive relation between different enzymes is weakened, the reaction sites of the enzymes are increased, and two different kinds of treatment pulp are mixed and beaten under the same concentration; the paper pulp performance is improved under the condition that fibers are not damaged, and the pulping energy consumption is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of papermaking, and in particular to an enzymatic pulping process for improving the performance of cultural paper and an application thereof. Background Art

[0002] Global energy consumption and environmental issues have become one of the most severe challenges in today's society, and the papermaking industry has always been known for its high energy consumption and high pollution. Although with the improvement of people's awareness of environmental protection, the papermaking industry is moving towards low energy consumption and low pollution, energy loss and environmental pollution in the pulping and papermaking process are still unavoidable. In the pulping and papermaking process, pulp refining is an important step to give paper special properties, and it is also one of the papermaking sections with the highest energy consumption.

[0003] There are many fiber bundles in the unbeaten pulp. Because the fibers are thick and long, and the surface is smooth, hard and elastic, the fiber specific surface area is small and lacks bonding properties. The unbeaten pulp is used for papermaking. The fibers are easily entangled with each other, and the paper is loose and porous, with a rough surface and easy to fluff. The bonding strength is low, the paper performance is poor, and it cannot meet the requirements of use. The continuous development and progress of biotechnology has gradually shown its superiority in the field of pulping and papermaking, and has some mature applications, achieving good economic and environmental ecological benefits, and has become one of the driving forces for promoting the green and sustainable development of my country's pulping and papermaking industry. For example, enzymatic pulping technology, the pulp is pretreated with enzymes before pulping to promote the fiber fibrillation and fibrillation, reduce the fiber resistance, make it easy to separate, and thus reduce the energy consumption in the pulping process. In the enzymatic pulping process, cellulase or hemicellulase is often used for pretreatment to give fiber characteristics and reduce energy loss. However, there are many types of enzymes on the market, and different enzyme preparations will have different effects on substrates at different temperatures and pH values. Even if the same enzyme preparation is applied to pulp from different sources, the fibers will show great differences. The variable reaction conditions and reaction results restrict the application of enzyme preparations in the field of pulping and papermaking. Summary of the invention

[0004] The purpose of the present invention is to provide an enzymatic pulping process and its application for improving the performance of cultural paper in view of the above-mentioned deficiencies in the prior art, using acetic acid / sodium acetate buffer solution to cooperate with enzyme to enzymolyze fibers, thereby reducing energy consumption and enhancing paper strength.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] The first object of the present invention is to provide an enzymatic pulping process for improving the performance of cultural paper, comprising the following steps:

[0007] S1. Pour the mixture of acetic acid / sodium acetate buffer solution and bleached eucalyptus pulp into a reactor for preheating at a reaction temperature of 30-50°C;

[0008] S2, the preheated bleached eucalyptus pulp is divided into two constant temperature tanks A1 and A2, endoglucanase is added to A1, and xylanase and pectinase are added to A2, and after the reaction time is preset, the pulp is inactivated;

[0009] S3. Take 0-30 g of absolute dry pulp from A1 and A2 respectively, mix them evenly, adjust the pulp concentration to 3-10% with ionized water, and refine the pulp in a PFI refiner.

[0010] Furthermore, the pH value of the acetic acid / sodium acetate buffer solution is 4.8±0.1.

[0011] Furthermore, the bleached eucalyptus pulp is sulfate bleached eucalyptus pulp.

[0012] Furthermore, the enzyme activity of the endoglucanase is 20,000 to 200,000 U / g, the enzyme activity of the pectinase is 20,000 to 200,000 U / g, and the enzyme activity of the xylanase is 20,000 to 200,000 U / g.

[0013] Furthermore, the dosage of the pectinase can be selected to be 5 to 40 U / g.

[0014] Furthermore, the dosage of the endoglucanase can be selected to be 5 to 20 U / g.

[0015] Furthermore, the dosage of the xylanase can be selected to be 5 to 40 U / g.

[0016] Furthermore, the PFI refining speed is 8000-15000r; the refining gap is 0.1-0.35mm, and the refining pulp concentration is 3-10%.

[0017] The second object of the present invention is to provide the use of the pulp prepared by the above-mentioned pulping process in the preparation of cultural paper.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] (1) The present invention provides an enzymatic pulping process for improving the performance of cultural paper. Compared with the conventional pulping process, two different enzyme pretreatment steps are added. On the one hand, the fiber surface of bleached eucalyptus sulfate pulp is relaxed and activated under the joint action of acetic acid / sodium acetate buffer solution and endoglucanase to achieve latent delamination of the fiber cell wall. Subsequently, under mechanical action, the fiber is crushed, swollen and fibrillated, thereby reducing the use of chemicals and reducing the energy consumption in the process of converting the fiber into microfibrillated cellulose. On the other hand, the fine fibers on the fiber surface of bleached eucalyptus sulfate pulp are reduced under the joint action of acetic acid / sodium acetate buffer solution, xylanase and pectinase, and the average length of the fiber is increased. The hemicellulose on the fiber surface is removed, making the fiber more supple and slender, and the fibers are more closely interwoven, thereby improving the physical properties of the paper. The former can fibrillate the pulp so that it is better dispersed in the long fiber network, and the latter provides a long fiber network. Mixing the pulp treated with two steps of enzymes can not only ensure that the pulp can reach the corresponding beating degree at low energy consumption, but also ensure the strength performance of the fiber;

[0020] (2) Compared with the traditional pulping process, it can act on the fibers more efficiently, reduce excessive fiber loss, and thus reduce pulping energy consumption and improve paper performance;

[0021] (3) The present invention can relatively reduce the competition between different enzymes and improve the effective utilization of enzymes;

[0022] (4) Compared with chemical methods, the present invention uses less liquid medicine, does not form accumulation in the system, does not cause imbalance in the pulp system, and reduces the impact on the environment. The addition of specific enzymes helps to reduce the amount of chemicals used, has less odor and is non-corrosive, and is safe and friendly to workshop operators. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is the variation diagram of specific beating energy consumption of bleached eucalyptus pulp treated with endoglucanase at different enzyme dosages and refining revolutions;

[0024] Figure 2 This is a scanning electron micrograph of bleached eucalyptus pulp without enzyme treatment;

[0025] Figure 3 Scanning electron micrograph of bleached eucalyptus pulp treated with xylanase;

[0026] Figure 4 Scanning electron micrograph of bleached eucalyptus pulp treated with endoglucanase;

[0027] Figure 5 Scanning electron micrograph of bleached eucalyptus pulp treated with pectinase. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical solution and advantages of the present invention clearer, embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements with the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0029] The reagents and experimental materials used in the present invention can be obtained commercially.

[0030] In this embodiment, the kraft bleached eucalyptus pulp board is provided by a paper mill in Hunan.

[0031] Preparation of acetic acid / sodium acetate buffer solution in this example: weigh 8.02 g of sodium acetate trihydrate, add 3.5 mL of glacial acetic acid, dissolve in water, dilute to 1000 mL, and measure its pH. If the pH deviates from 4.8, adjust it to 4.8±0.1 with 0.1 mol / L acetic acid or sodium acetate solution.

[0032] Example 1

[0033] This embodiment provides an enzymatic pulping process for improving the performance of cultural paper, and the specific steps are as follows:

[0034] (1) 360 g of bleached eucalyptus kraft pulp board was soaked in 5 L of distilled water for more than 4 hours, and the soaked pulp board was torn into pulp pieces of 4 cm × 4 cm in size, and the soaked small pieces of pulp were debonded with a Wall-E pulper until the fibers in the pulp were evenly dispersed, and then the pulp was taken out and dried, put into a sealed bag, and refrigerated in a refrigerator to balance the moisture;

[0035] (2) setting the dosage gradient of endoglucanase and xylanase at the selected pH, pulp concentration and temperature for enzyme treatment for 60 minutes, and continuously washing the pulp with deionized water after the reaction, and re-adjusting the pulp concentration to 10% after the washing, and measuring the pulp beating degree and paper performance changes at different rotation speeds;

[0036] (3) The pulp concentration is prepared to be 4%. The acetic acid / sodium acetate buffer solution and the bleached eucalyptus kraft pulp are mixed and poured into a reactor for preheating at a reaction temperature of 30-50° C. The preheated bleached eucalyptus pulp is divided into two thermostatic tanks A1 and A2. 5 U / g endoglucanase is added to A1, and 10 U / g xylanase and 5 U / g pectinase are added to A2. The mixture is stirred every 10 minutes. After reacting for 60 minutes, the enzymes are inactivated.

[0037] (4) After the enzyme pretreatment, 15 g of absolute dry pulp was taken from A1 and A2 respectively, and the pulp was mixed to set the pulp concentration to 10%, and the pulp was refined in a PFI refiner.

[0038] Refining conditions: pulp concentration 10%, refining gap 0.2mm, speed 8000r, measure the beating degree and energy consumption;

[0039] (5) Testing of physical properties of hand sheets: PFI pulp was made into 60 g / m2 using a fast paper former. 2 Each group of hand-coated sheets was made into 6 to 10 sheets. After being balanced in a constant temperature and humidity laboratory at a temperature of (23±1)°C and a relative humidity of (50±2)% for 4 hours, relevant physical properties were tested.

[0040] In this embodiment, two different enzyme pretreatments are added to the conventional pulping process. On the one hand, the bleached sulphate eucalyptus pulp is subjected to the combined action of acetic acid / sodium acetate buffer solution and endoglucanase to relax and activate the fiber surface, realize the latent delamination of the fiber cell wall, and subsequently promote fiber crushing, swelling and fine fiberization under mechanical action, thereby reducing the use of chemicals and reducing the energy consumption in the process of fiber conversion into microfibrillated cellulose; on the other hand, the bleached sulphate eucalyptus pulp is subjected to the action of acetic acid / sodium acetate buffer solution, xylanase and pectinase to reduce the fine fibers on the fiber surface, increase the average length of the fiber, remove the hemicellulose on the fiber surface, make the fiber more supple and slender, and interweave the fibers more closely, thereby improving the physical properties of the paper. Mixing the pulp treated with the two steps of enzymes can not only ensure that the pulp can reach the corresponding beating degree under low energy consumption, but also ensure the strength performance of the fiber. Subsequently, the pulp is refined in a PFI refiner, and the refining conditions are: pulp concentration 10%, refining gap 0.2mm, and speed 8000r. The pulp is used to make paper with a basis weight of 60g / m 2 The enzyme dosage was determined to be 5U / g endoglucanase, 5U / g pectinase, and 10U / g xylanase, which increased the beating degree by 17.3-22.3%, significantly reduced the beating energy consumption, improved the fiber morphology distribution, and enhanced the strength performance of the finished paper.

[0041] Example 2

[0042] This embodiment provides an enzymatic pulping process for improving the performance of cultural paper, which is basically the same as Example 1, except that different amounts of xylanase added are examined: 0 U / g, 10 U / g, 20 U / g, 30 U / g, and 40 U / g.

[0043] Example 3

[0044] This embodiment provides an enzymatic pulping process for improving the performance of cultural paper, which is basically the same as Example 1, except that different amounts of endoglucanase added are examined: 0U / g, 5U / g, 10U / g, 15U / g, and 20U / g.

[0045] Comparative Example 1

[0046] This comparative example provides an enzymatic pulping process.

[0047] The method is basically the same as Example 1, except for the first stage of enzyme treatment: the pulp concentration is 4%, the acetic acid / sodium acetate buffer solution and the bleached eucalyptus pulp are mixed and poured into the reactor for preheating, the reaction temperature is 30-50°C, 5U / g endoglucanase, 5U / g pectinase, and 10U / g xylanase are added, and the mixture is stirred every 10 minutes. After the reaction for 60 minutes, the enzyme is inactivated. After the enzyme pretreatment is completed, 30g of the absolute dry pulp is taken and mixed, and the pulp concentration is set to 10%. The pulp is refined in the PFI refiner. Finally, the PFI pulp is made into 60g / m 2 Each group of hand-coated sheets was made into 6 to 10 sheets. After being balanced in a constant temperature and humidity laboratory at a temperature of (23±1)°C and a relative humidity of (50±2)% for 4 hours, relevant physical properties were tested.

[0048] Comparative Example 2

[0049] This comparative example provides a pulping process.

[0050] (1) 360 g of bleached eucalyptus kraft pulp board was soaked in 5 L of distilled water for more than 4 hours, and the soaked pulp board was torn into pulp pieces of 4 cm × 4 cm in size, and the soaked small pieces of pulp were debonded with a Wall-E pulper until the fibers in the pulp were evenly dispersed, and then the pulp was taken out and dried, put into a sealed bag, and refrigerated in a refrigerator to balance the moisture;

[0051] (2) Pour the bleached eucalyptus kraft pulp into a reactor to preheat the pulp to a pulp concentration of 4% at a reaction temperature of 30 to 50° C., stir the pulp every 10 minutes, and react for 60 minutes;

[0052] (3) After the hydrothermal pretreatment, 30 g of absolute dry pulp was mixed and the pulp concentration was set to 10%, and the pulp was refined in a PFI refiner.

[0053] Refining conditions: pulp concentration 10%, refining gap 0.2mm, speed 8000r, measure the beating degree and energy consumption;

[0054] (4) Testing of physical properties of hand sheets: PFI pulp was refining and made into 60 g / m2 paper using a fast paper former. 2 Each group of hand-coated sheets was made into 6 to 10 sheets. After being balanced in a constant temperature and humidity laboratory at a temperature of (23±1)°C and a relative humidity of (50±2)% for 4 hours, relevant physical properties were tested.

[0055] Comparative Example 3

[0056] This comparative example provides an enzymatic pulping process.

[0057] (1) 360 g of bleached eucalyptus kraft pulp board was soaked in 5 L of distilled water for more than 4 hours, and the soaked pulp board was torn into pulp pieces of 4 cm × 4 cm in size, and the soaked small pieces of pulp were debonded with a Wall-E pulper until the fibers in the pulp were evenly dispersed, and then the pulp was taken out and dried, put into a sealed bag, and refrigerated in a refrigerator to balance the moisture;

[0058] (2) using deionized water to prepare a pulp concentration of 4%, pouring the bleached eucalyptus kraft pulp into a reactor for preheating at a reaction temperature of 30-50° C., placing the preheated bleached eucalyptus pulp into two thermostatic tanks A1 and A2, adding 5 U / g endoglucanase to A1, and adding 10 U / g xylanase and 5 U / g pectinase to A2, stirring once every 10 minutes, and inactivating the enzymes after reacting for 60 minutes;

[0059] (3) After the enzyme pretreatment, 15 g of absolute dry pulp was taken from A1 and A2 respectively, mixed, and the pulp concentration was set to 10%, and the pulp was refined in a PFI refiner.

[0060] Refining conditions: pulp concentration 10%, refining gap 0.2mm, speed 8000r, measure the beating degree and energy consumption;

[0061] (4) Testing of physical properties of hand sheets: PFI pulp was refining and made into 60 g / m2 paper using a fast paper former. 2 Each group of hand-coated sheets was made into 6 to 10 sheets. After being balanced in a constant temperature and humidity laboratory at a temperature of (23±1)°C and a relative humidity of (50±2)% for 4 hours, relevant physical properties were tested.

[0062] Comparative Example 4

[0063] (1) 360 g of bleached eucalyptus kraft pulp board was soaked in 5 L of distilled water for more than 4 hours, and the soaked pulp board was torn into pulp pieces of 4 cm × 4 cm in size, and the soaked small pieces of pulp were debonded with a Wall-E pulper until the fibers in the pulp were evenly dispersed, and then the pulp was taken out and dried, put into a sealed bag, and refrigerated in a refrigerator to balance the moisture;

[0064] (2) using a sodium acetate buffer solution to prepare a pulp concentration of 4%, pouring the bleached eucalyptus kraft pulp into a reactor for preheating at a reaction temperature of 30-50° C., adding 5 U / g endoglucanase and 5 U / g pectinase to the preheated bleached eucalyptus pulp, stirring once every 10 minutes, and inactivating the enzymes after reacting for 60 minutes;

[0065] (3) After the enzyme pretreatment, 30 g of absolute dry pulp was taken, the pulp concentration was set to 10%, and the pulp was refined in a PFI refiner.

[0066] Refining conditions: pulp concentration 10%, refining gap 0.2mm, speed 8000r, measure the beating degree and energy consumption;

[0067] (4) Testing of physical properties of hand sheets: PFI pulp was refining and made into 60 g / m2 paper using a fast paper former. 2 Each group of hand-coated sheets was made into 6 to 10 sheets. After being balanced in a constant temperature and humidity laboratory at a temperature of (23±1)°C and a relative humidity of (50±2)% for 4 hours, relevant physical properties were tested.

[0068] like Figure 1 As shown in the figure, with the increase of endoglucanase dosage, the energy consumption of pulp beating decreases. When the enzyme dosage reaches 10U / g, the change of specific energy consumption tends to be stable. This is because endoglucanase promotes the fibrillation of fibers and provides a latent structure for fibers. After pulping, this structure of fibers collapses, and it is easier to form a filter layer between fibers. The fiber beating degree is improved, and the increase in interweaving between fibers also increases the strength performance of paper to a certain extent, as shown in Table 1.

[0069] The calculation formula for specific beating energy consumption in the figure is:

[0070]

[0071] In the formula: SEC is the specific pulping energy consumption, W is the pulping energy consumption at the current beating degree, m is the absolute dry weight of the pulp, d is the current beating degree value, and 400 is the expansion factor. In order to facilitate the observation of energy consumption changes, the pulping energy consumption changes are expanded 400 times.

[0072] like Figure 2-Figure 5 As shown in the figure, the fiber surface without enzyme treatment is smooth and the fiber morphology is obvious; after xylanase treatment, the xylan on the fiber surface is decomposed and some non-cellulose components are removed. This makes the fiber more flexible and easy to deform, thereby increasing the tear resistance of the paper. Although the fiber kink index has not been significantly improved, at the microscopic level, xylanase treatment may make the fiber surface more "rough" or have tiny grooves, which helps the physical interlacing between fibers. This interlaced structure increases the support force of the fiber under the action of tearing force, thereby increasing the tearing degree. After endoglucanase treatment, the fiber has some wrinkles and kinks, some small holes appear on the fiber surface, and even begins to break and form small fiber pieces. The increase of fine fibers filling between fibers greatly improves the pulp beating degree and reduces the energy consumption of pulp beating; pectinase can decompose the pectin component in the plant cell wall, reduce the bonding force of the fiber, make the fiber easier to separate and handle, and improve the flexibility of the fiber: through the degradation of pectin, the flexibility and elasticity of the fiber may be improved, thereby improving the feel and processing performance of the fiber.

[0073] The changes in the physical properties of paper in different pulping methods were investigated, and the results are shown in Table 1:

[0074] Table 1. Changes in physical properties of bleached eucalyptus pulp paper treated with different pulping methods

[0075]

[0076] As shown in Table 1, the paper tensile index, bursting index and tearing index in the embodiment of the paper physical properties change in different beating methods are 44.33N·m / g, 2.53KPa·m 2 / g, 5.18mN·m 2 / g, under the same energy consumption, the pulp beating degree is increased to 37°SR, compared with comparative example 2, the tensile strength of the paper is increased by 18.40%, the bursting strength is increased by 12.44%, the tear strength is increased by 6.15%, and the pulping energy consumption is reduced by 42.31%; Comparative example 1 is a one-step enzyme treatment with acetic acid / sodium acetate synergistic enzyme. Although it is partially improved compared with comparative example 2, the joint treatment of the three enzymes causes a certain damage to the fiber properties and the paper performance decreases; Comparative example 3 lacks the synergistic effect of acetic acid / sodium acetate, and there is a certain competitive relationship between the three enzymes, and the enzyme cannot be fully utilized. In comparative example 4, the cutting of the fiber by endoglucanase reduces the average length of the fiber, and its tear strength also decreases accordingly.

[0077] The changes in the physical properties of paper with different xylanase addition amounts were investigated, and the results are shown in Table 2:

[0078] Table 2. Changes in paper properties at different dosages of xylanase

[0079]

[0080] As shown in Table 2, the physical properties of paper change under different xylanase addition amounts. When the enzyme dosage is 0-40U / g, the tensile strength and bursting resistance are less affected by the enzyme dosage. When the enzyme dosage is 20U / g, the tensile index of the paper reaches the optimal value, but its bursting resistance index decreases. The tear strength gradually improves with the increase of enzyme dosage, reaching the maximum at 40U / g. In order to ensure the integrity of the fiber, the enzyme dosage is selected to be 10U / g.

[0081] Table 3. Changes in paper properties at different dosages of endoglucanase

[0082]

[0083] It can be seen from Table 3 that endoglucanase can significantly improve the beating degree of the pulp after PFI. The beating degree gradually increases with the increase of enzyme dosage. When the enzyme dosage is 5U / g, the tensile strength and bursting resistance of the paper are improved to a certain extent. However, with the increase of enzyme dosage, the fiber properties are damaged. Various indicators of the paper decrease with the increase of enzyme dosage, especially the tear resistance of the paper decreases significantly.

[0085] For matters not mentioned above, the prior art applies.

[0086] Although some specific embodiments of the present invention have been described in detail through examples, those skilled in the art should understand that the above examples are for illustration only and are not intended to limit the scope of the present invention. Those skilled in the art to which the present invention belongs may make modifications or supplements to the described specific embodiments or replace them in a similar manner, but they will not deviate from the direction of the present invention or exceed the scope defined by the attached claims. Those skilled in the art should understand that any modifications, equivalent substitutions, improvements, etc. made to the above implementations based on the technical essence of the present invention should be included in the protection scope of the present invention.

Claims

1. An enzymatic pulping process for improving the performance of cultural paper, characterized in that: The following steps are involved: S1. Pour the mixture of acetic acid / sodium acetate buffer solution and bleached eucalyptus pulp into a reactor for preheating at a reaction temperature of 30-50°C; S2, the preheated bleached eucalyptus pulp is divided into two constant temperature tanks A1 and A2, endoglucanase is added to A1, and xylanase and pectinase are added to A2, and after the reaction time is preset, the pulp is inactivated; S3. Take 10-30 g of absolute dry pulp from A1 and A2 respectively, mix them evenly, adjust the pulp concentration to 3-10% with deionized water, and refine the pulp in a PFI refiner.

2. The enzymatic pulping process according to claim 1, characterized in that: The pH value of the acetic acid / sodium acetate buffer solution is 4.8±0.

1.

3. The enzymatic pulping process according to claim 1, characterized in that: The bleached eucalyptus pulp is kraft bleached eucalyptus pulp.

4. The enzymatic pulping process according to claim 1, characterized in that: The enzyme activity of the endoglucanase is 20000-200000 U / g, the enzyme activity of the pectinase is 20000-200000 U / g, and the enzyme activity of the xylanase is 20000-200000 U / g.

5. The enzymatic pulping process according to claim 4, characterized in that: The dosage of the endoglucanase is 5-20 U / g.

6. The enzymatic pulping process according to claim 1, characterized in that: The dosage of the pectinase is 5-40 U / g.

7. The enzymatic pulping process according to claim 1, characterized in that: The dosage of the xylanase is 5-100 U / g.

8. The enzymatic pulping process according to claim 1, characterized in that: The PFI refining speed is 8000-15000r; the refining gap is 0.1-0.35mm, and the refining pulp concentration is 3-10%.

9. Use of pulp prepared by the enzymatic pulping process according to any one of claims 1 to 8 in the preparation of cultural paper.

Images