High performance kraft paper and preparation method and application thereof

Abstract

The application discloses high-performance kraft paper and a preparation method and application thereof. In the application, three kinds of fiber raw materials, bleached kraft pulp, bamboo fiber and bamboo powder are compounded to form a paper sample, and a polyvinyl alcohol barrier coating with water resistance and gas barrier performance is coated on the surface of the paper sample, so that the strength of the kraft paper is increased, the surface pore structure of the kraft paper is improved, and the oxygen resistance and antibacterial capacity are increased. The high-performance kraft paper prepared in the application has good mechanical properties, barrier properties and antibacterial properties, and can be used in the field of mildew-resistant and antibacterial packaging materials for drugs.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of packaging materials, in particular to a high-performance kraft paper and a preparation method and application thereof. BACKGROUND

[0002] It is known that, during the production, circulation and storage of drugs, if the storage method is improper, under the action of external conditions (temperature, humidity, microorganisms, etc.) and its own properties, physical or chemical changes will gradually occur, such as mold, insect damage, taste change, deterioration and the like, which directly affect the quality and safety of the drugs. This phenomenon is not only related to the properties of the drugs themselves, but also closely related to the external environment. Barrier packaging materials usually have the functions of moisture resistance, gas resistance, antibacterial and the like, and can effectively protect the quality of the drugs and prolong the shelf life. At the present stage, the barrier packaging materials commonly used are mainly plastics, metals, glass and the like. The packaging materials based on biological substrates have obvious environmental protection advantages because the raw materials are derived from natural biomass resources, and play an important role in promoting green and low-carbon packaging. Compared with plastics, paper has many advantages such as renewability, biodegradability and recyclability, and is widely used in the packaging field. However, the paper forming process is to form a fiber slurry on a screen, which belongs to a porous structure material, and the self-blocking ability cannot meet the actual packaging requirements. In order to obtain good water resistance, oil resistance, antibacterial and gas barrier properties, the common method is to coat a plastic film on the surface of the paper or to be compounded with aluminum foil and plastic and the like, but this will affect the recycling of the paper. Therefore, researchers use barrier coatings to replace plastic films to realize the recycling of the packaging paper.

[0003] Kraft paper is usually made of pure wood pulp and has a tightly interwoven cellulose fiber structure, which has very good carrying capacity and is not easy to tear. In addition, the production cost is low, so kraft paper is an ideal choice for packaging materials and has many application scenarios in daily life. At present, some enterprises use kraft paper bags for the packaging of drugs or medical devices, but there are still some problems, such as poor comprehensive performance, for example, the mechanical performance is not outstanding and cannot withstand strong external force damage; the barrier ability is limited and it is difficult to achieve high barrier; the antibacterial and antibacterial ability is very weak and easy to mold and deteriorate, which leads to the fact that kraft paper has a small range of use in drug packaging. Therefore, it is very important and has practical significance to develop an environmentally friendly high-performance kraft paper, which will help to build a sustainable development of high-performance paper-based packaging materials and effectively promote the high-quality development of the packaging industry towards green and functional direction. SUMMARY

[0004] The primary purpose of the present application is to overcome the shortcomings and deficiencies of the prior art, and the primary purpose of the present application is to provide a preparation method of high-performance kraft paper.

[0005] Another purpose of the present application is to provide a high-performance kraft paper prepared by the preparation method.

[0006] Still another object of the present application is to provide the use of the high-performance kraft paper.

[0007] The object of the present application is achieved by the following technical solutions:

[0008] A preparation method of high-performance kraft paper, comprising the following steps:

[0009] (1) Slurry compounding: bleached kraft pulp of wet pine fiber (PF) and bamboo fiber (SAF) are respectively subjected to beating treatment, and then PF dispersion liquid and SAF dispersion liquid are obtained after sufficient dispersion treatment, and then the PF dispersion liquid and the SAF fiber dispersion liquid are uniformly mixed to obtain PF / SAF compound slurry; finally, bamboo powder (BP) is added to the PF / SAF compound slurry under stirring to obtain PF / SAF / BP mixed slurry;

[0010] (2) Forming papermaking: the PF / SAF / BP mixed slurry obtained in step (1) is formed into a shape, and then dehydrated and dried to obtain paper sample I;

[0011] (3) Preparation of barrier coating: montmorillonite is ultrasonically dispersed in water to obtain a montmorillonite suspension; polyvinyl alcohol is added to water, and the temperature is raised to 95±5 ℃ for stirring and dissolution to obtain a polyvinyl alcohol solution; then the polyvinyl alcohol solution is added to the montmorillonite suspension, and glycerol (plasticizer), tributyl phosphate (defoaming agent) and sodium tetraborate are added, and the temperature is lowered to 80±5 ℃ for stirring and reaction, and then the reaction is stopped and defoaming is performed to obtain a barrier coating material;

[0012] (4) Coating treatment: the barrier coating material liquid obtained in step (3) is diluted with water and coated on both sides of the paper sample I obtained in step (2), and then infrared drying is performed to obtain paper sample II;

[0013] (5) Post-treatment: the paper sample II obtained in step (4) is subjected to heat pressing and drying treatment to obtain high-performance kraft paper.

[0014] The length of the bleached kraft pulp of wet pine fiber in step (1) is 2-15 mm, and the diameter is 22-48 μm; the length of the bamboo fiber is 3-9 mm, and the diameter is 26-37 μm.

[0015] The beating treatment in step (1) is performed by a Val pulp beater.

[0016] In step (1), the bleached sulfate wet pine fibers are treated by a Val pulp machine under the conditions of 8000-12000 revolutions, 2.5-3.0 wt% of pulp consistency, and 55-70°SR of pulp degree; and the bamboo fibers are treated by a Val pulp machine under the conditions of 6000-8000 revolutions, 1.0-2.0 wt% of pulp consistency, and 40-50°SR of pulp degree.

[0017] In the dispersion treatment in step (1), the bleached sulfate wet pine fibers are dispersed in a cell wall breaker at a speed of 6000-8000 r / min for 10-20 min at a concentration of 1.0-1.5% by mass; and the bamboo fibers are dispersed in a cell wall breaker at a speed of 3000-5000 r / min for 5-10 min at a concentration of 1.0-1.5% by mass.

[0018] In step (1), the dry mass ratio of the bleached sulfate wet pine fibers to the bamboo fibers in the PF / SAF compound pulp system is (5-8):(2-5).

[0019] In step (1), the bamboo powder of the bamboo is a nano bamboo powder; preferably, the bamboo powder has a particle size of 30-300 nm; further preferably, the bamboo powder is prepared by mechanically grinding bamboo chips, and the preparation method comprises the following steps: mechanically grinding the bamboo chips at 30-35 ℃ and 4000-6000 rpm to obtain the bamboo powder with a particle size of 30-300 nm.

[0020] The number of mechanical grinding is 3-5 times.

[0021] In step (1), the addition amount of the bamboo powder is 2.0-5.0% by mass of the dry mass of the PF / SAF / BP mixed pulp.

[0022] In step (1), the stirring speed is 5000-8000 r / min.

[0023] In step (2), the pulp consistency of the PF / SAF / BP mixed pulp is 1.3-1.6% by mass.

[0024] In step (2), the forming is performed by a Fourdrinier former.

[0025] In step (3), the mass ratio of the montmorillonite to the polyvinyl alcohol is (1-3):(5-7).

[0026] In step (3), the ultrasonic dispersion time is 20-30 min.

[0027] The glycerol used in step (3) accounts for 3-6% of the total volume of the reaction system.

[0028] The tributyl phosphate used in step (3) accounts for 1-2% of the total volume of the reaction system.

[0029] The sodium tetraborate used in step (3) accounts for 4-7% of the mass of the montmorillonite.

[0030] The stirring time in step (3) is 40-60 min.

[0031] The standing time in step (3) is 12-18 h.

[0032] The concentration of the barrier coating material used in step (4) is 1.0-1.5% by mass.

[0033] The coating conditions in step (4) are as follows: the coating speed is 15-30 m / min, and the single-sided coating amount is 1.5-2.5 g / m 2 .

[0034] The infrared drying conditions in step (4) are as follows: the coated paper sample is subjected to infrared drying at 90-130 ℃ for 20-30 min using an electric infrared generator.

[0035] The hot-pressing conditions in step (5) are as follows: the temperature is 96-110 ℃, the pressure is 20-25 MPa, and the time is 10-20 min.

[0036] The drying conditions in step (5) are as follows: infrared drying is performed at 41-48 ℃ for 40-80 min.

[0037] A high-performance kraft paper is prepared by the above preparation method.

[0038] The performance indicators of the high-performance kraft paper are as follows: basis weight: 36-43 g / m 2 ; tensile strength: 2.91-3.67 kN / m; tear strength: 731.5-789.2 mN; oxygen transmission rate: 304-412 cm 3 / m 2 ·day·0.1 MPa; water vapor transmission rate: 96-128 g / m 2 ·day; and antibacterial rate: 92.4-98.3%.

[0039] The high-performance kraft paper is applied to packaging materials.

[0040] The packaging material includes a mildew-resistant and antibacterial packaging material; and preferably a mildew-resistant and antibacterial packaging material for drug packaging (a mildew-resistant and antibacterial packaging material for drugs).

[0041] The present application has the following advantages and effects relative to the prior art:

[0042] (1) The wet pine fiber, the bamboo fiber and the bamboo powder used in the present application are all plant-based materials that can be degraded, and the kraft paper prepared from these raw materials can be naturally degraded or recycled, thus belonging to an environmentally friendly packaging material, and can be used in the field of drug packaging to replace plastic with paper, thus meeting the concept of green and sustainable development.

[0043] (2) The high-performance kraft paper prepared in the present application is obtained by reasonably compounding three types of fiber raw materials, and fully utilizes the advantages of different types of fibers: the wet pine fiber is long and high-strength, and can significantly improve the physical strength of the paper; the bamboo fiber is fine and soft, and has good fiber morphology, and has the softness of broadleaf wood and the flexibility of coniferous wood, thus ensuring the close combination between fibers; in addition, the bamboo fiber contains bamboo charcoal, and has the natural properties of bacteriostasis, anti-mite, deodorization and insect prevention, thus improving the mildew-resistant and antibacterial effect of the kraft paper; the bamboo powder has a nanoscale size and a large specific surface area, and belongs to a natural nanoscale antibacterial agent, which can be well filled between the wet pine fiber and the bamboo fiber, improve the interfacial bonding force between different fibers, and make the long fibers and the short fibers closely connected, thus improving the mechanical strength of the kraft paper.

[0044] (3) The present application independently prepares an environmentally friendly barrier coating, and the polyvinyl alcohol is a polymer that can be degraded, and belongs to an environmentally friendly product. The polyvinyl alcohol itself has good gas barrier properties, but has poor water resistance, and is easy to lose gas barrier properties in a highly humid environment, thus a polyvinyl alcohol barrier coating with water resistance and gas barrier properties is prepared by modification, and through a coating process, the strength of the kraft paper can be increased, and the surface pore structure of the kraft paper can be improved, thus further increasing the oxygen resistance and antibacterial capacity.

[0045] (4) The two sides of the paper web are dehydrated by the gap former, which can overcome the problems of fiber flocculation, non-uniformity of the paper web along the thickness direction, different fiber components and interlaced states of the web surface and the blanket surface, and different properties of the two sides of the paper web. The use of the gap former in the present application can make the two sides of the paper web have similar properties, the outer surface of the paper web has a good fiber interlaced state, the physical properties and basis weight of the paper web are more uniform, and the longitudinal and transverse strengths and the property difference of the two sides of the obtained paper are small, which is beneficial to improving the mechanical properties and overall quality of the kraft paper; and the wet heat pressing treatment is beneficial to the softening and interlacing of the fibers, the uniformity of the kraft paper, the close combination of fibers of different sizes, and the strong toughness and compactness of the kraft paper.

[0046] (5) The high-performance kraft paper prepared by the method has good mechanical properties, barrier properties and antibacterial properties, can be used for the field of mildew-resistant and antibacterial packaging materials for drugs, and will promote the green, low-carbon and high-quality development of the packaging industry, and help the double-carbon target. BRIEF DESCRIPTION OF DRAWINGS

[0047] Figure 1 is a preparation flowchart of the high-performance kraft paper of the present application.

[0048] Figure 2 is a preparation process schematic diagram of the high-performance kraft paper of the present application.

[0049] Figure 3 is a scanning electron microscope image of the surface of the coated kraft paper in Example 1 of the present application. DETAILED DESCRIPTION

[0050] The present application will be further described in conjunction with the examples, but the embodiments of the present application are not limited thereto. Unless otherwise specified, the reagents, methods and devices used in the present application are conventional reagents, methods and devices in the technical field. Unless otherwise specified, the test methods in the following examples are usually carried out according to conventional experimental conditions or according to the experimental conditions recommended by the manufacturer. Unless otherwise specified, the reagents and raw materials used in the present application are commercially available.

[0051] 1. The bleached kraft pulp of wet pine fiber (PF) involved in the examples and comparative examples of the present application is taken from the State Key Laboratory of Pulp and Paper Engineering, with a length of 2-15 mm and a diameter of 22-48 μm; the bamboo fiber (SAF) is taken from the State Key Laboratory of Pulp and Paper Engineering, with a length of 3-9 mm and a diameter of 26-37 μm; the fiber of broussonetia papyrifera bark (TF) is taken from the State Key Laboratory of Pulp and Paper Engineering, with a length of 3-15 mm and a diameter of 28-40 μm; the bleached kraft pulp of wet pine fiber (PF) is taken from the State Key Laboratory of Pulp and Paper Engineering, with a length of 2-10 mm and a diameter of 32-45 μm.

[0052] 2. The nanoscale bamboo powder involved in the examples and comparative examples of the present application is prepared by mechanical pulverization with Cymbidium leaf as raw material; wherein the mechanical pulverization conditions are: pulverization for 3-5 times at 30-35 ℃ and a rotation speed of 4000-6000 rpm, and drying treatment to obtain nanoscale bamboo powder (BP) with a particle diameter of 30-300 nm.

[0053] 3. The coating liquid involved in the embodiments and comparative examples of this invention is a barrier coating prepared in the laboratory, specifically prepared through the following steps: 1-3g of montmorillonite is placed in a beaker containing 30g of deionized water, stirred and dispersed, and then ultrasonically dispersed in an ultrasonic vibrating disperser for 20-30 min to obtain a montmorillonite suspension; 5-7g of polyvinyl alcohol (molecular weight 1.36 x 10) is weighed. 5 Place the solution in a beaker containing 60 g of deionized water, then place it in a water bath. First, stir at low speed at room temperature, then raise the temperature to 95±5 ℃ and stir at high speed until the polyvinyl alcohol is completely dissolved. Add the prepared montmorillonite suspension, followed by 3.0–4.5 ml of glycerol for plasticization and 1.0–1.5 ml of tributyl phosphate for defoaming. After sufficient reaction, slowly add 0.04–0.07 g of sodium tetraborate to the solution. Adjust the water bath temperature to 80±5 ℃ and stir at low speed for 40–60 min. Cool to room temperature and allow to stand for 12–18 h to defoam, obtaining the barrier coating required for the experiment. When using, dilute the barrier coating with water to a concentration of 1.0–1.5% by mass.

[0054] 4. The various parameters involved in the embodiments and comparative examples of this invention were tested according to national standard testing methods and industry standards, specifically as follows:

[0055] ① Quantitative (GB / T 451.2-2002);

[0056] ②Tensive strength (GB / T 453-2002);

[0057] ③ Tear strength (GB / T 455-2002);

[0058] ④Oxygen transmission rate (GB / T 19789-2005);

[0059] ⑤ Water vapor transmission rate (GB / T 22921-2008);

[0060] ⑥ Antibacterial rate (GB15979-2002): The selected colonies were Staphylococcus aureus (BNCC188012) or Escherichia coli (BNCC364150), both purchased from Beina Chuanglian Biotechnology Co., Ltd.

[0061] The preparation process of the high-performance packaging kraft paper in this invention is as follows: Figure 1 As shown in the diagram, the preparation process is illustrated below. Figure 2 As shown.

[0062] Example 1

[0063] This embodiment provides a method for preparing high-performance kraft paper, and the specific preparation steps are as follows:

[0064] (1) Slurry compounding: the bleached kraft pine fibers (PF, length of 2-15 mm, diameter of 22-48 μm) were treated by beating in a Valmet beater, the beating revolution was 8000 revolutions, the beating consistency was 2.5 wt%, and the beating degree was 55°SR; and the sinocalamus acuminatus fibers (SAF, length of 3-9 mm, diameter of 26-37 μm) were also treated by beating in a Valmet beater, the beating revolution was 6000 revolutions, the beating consistency was 1.0 wt%, and the beating degree was 40°SR. Then the bleached kraft pine fibers after beating were dispersed in a wall-breaking machine at a speed of 6000 r / min for 10 min at a concentration of 1.0 wt%, and the sinocalamus acuminatus fibers after beating were dispersed in a wall-breaking machine at a speed of 3000 r / min for 5 min at a concentration of 1.0 wt%. Finally, the bleached kraft pine fiber dispersion liquid and the sinocalamus acuminatus fiber dispersion liquid obtained after dispersion were uniformly mixed at a dry mass ratio of 8:5 (i.e. the mass ratio of bleached kraft pine fibers and sinocalamus acuminatus fibers, the same below), to obtain a PF / SAF compounded slurry; under the condition of high-speed stirring (speed: 5000 r / min), nano-sized bamboo powder (BP) (particle diameter of 30-300 nm) was added to the PF / SAF compounded slurry, the amount of bamboo powder (BP) added was 2.0% of the dry mass of the PF / SAF / BP mixed slurry, and the mixture was uniformly mixed to prepare a PF / SAF / BP mixed slurry.

[0065] (2) Forming papermaking: the PF / SAF / BP mixed slurry obtained in step (1) was formed, dewatered and dried on a gap former paper machine at a slurry concentration of 1.3 wt% to obtain a paper sample I.

[0066] (3) Preparation of barrier coating: 1 g of montmorillonite was put into a beaker containing 30 g of deionized water, stirred and dispersed, and put into an ultrasonic vibration disperser for ultrasonic dispersion for 20 min to obtain a montmorillonite suspension; 5 g of polyvinyl alcohol (molecular weight of 1.36 x 10 5 ) was weighed into a beaker containing 60 g of deionized water, put into a water bath, first stirred at room temperature at low speed, and then stirred at high speed after the temperature was raised to 93 ℃ until the polyvinyl alcohol was completely dissolved, then the prepared montmorillonite suspension was added, 3.0 ml of glycerol was added for plasticization, 1.0 ml of tributyl phosphate was added for defoaming, and after sufficient reaction, 0.04 g of sodium tetraborate was slowly added to the solution, the water bath temperature was adjusted to 80 ℃ and stirred at low speed for 40 min, then cooled to room temperature, and defoamed for 12 h to obtain the required barrier coating.

[0067] (4) Coating treatment: the barrier coating material obtained in step (3) is diluted with water and coated on both sides of the paper sample I obtained in step (2), wherein the use concentration of the barrier coating is 1.0 wt%, the coating speed is 15 m / min, and the single-side coating amount is 1.5 g / m 2 . After the double-side coating is completed, the coated paper sample is dried by infrared rays at 90 °C for 20 min using an electric infrared ray generator, to obtain a paper sample II.

[0068] (5) Post-treatment: the paper sample II obtained in step (4) is subjected to hydrothermal pressure treatment at a temperature of 96 °C and a pressure of 20 MPa for 10 min, and then is subjected to infrared ray drying at 41 °C for 40 min, to obtain a high-performance kraft paper.

[0069] The performance indexes of the high-performance kraft paper prepared in this example are as follows: basis weight: 36 g / m 2 ; tensile strength: 2.91 kN / m; tear strength: 731.5 mN; oxygen transmission rate: 412 cm 3 / m 2 ·day·0.1 MPa; water vapor transmission rate: 128 g / m 2 ·day; antibacterial rate against Escherichia coli is 92.4%; antibacterial rate against Staphylococcus aureus is 95.7%. The scanning electron microscope image of the surface of the kraft paper is shown in Figure 3 .

[0070] Example 2

[0071] This example provides a method for preparing a high-performance kraft paper, and the specific preparation steps are as follows:

[0072] (1) Slurry compounding: bleached kraft pine fibers (PF, length 2-15 mm, diameter 22-48 μm) were treated by beating in a Valmet beater, the beating revolutions were 9500, the beating consistency was 2.7 wt%, and the beating degree was 60°SR; and the bamboo fibers (SAF, length 3-9 mm, diameter 26-37 μm) were also treated by beating in a Valmet beater, the beating revolutions were 6500, the beating consistency was 1.4 wt%, and the beating degree was 45°SR. Then the bleached kraft pine fibers after beating were dispersed in a wall-breaking machine at a speed of 6500 r / min for 14 min at a concentration of 1.2 wt%, and the bamboo fibers after beating were dispersed in a wall-breaking machine at a speed of 4000 r / min for 7 min at a concentration of 1.3 wt%. Finally, the bleached kraft pine fiber dispersion liquid and the bamboo fiber dispersion liquid obtained after dispersion treatment were uniformly mixed at a dry mass ratio of 7:4 to obtain a PF / SAF compounded slurry; under the condition of high-speed stirring (speed: 6000 r / min), nano bamboo powder (BP) (particle diameter 30-300 nm) was added to the PF / SAF compounded slurry, the amount of bamboo powder (BP) added was 3.0% of the dry mass of the PF / SAF / BP mixed slurry, and the mixture was uniformly mixed to prepare a PF / SAF / BP mixed slurry.

[0073] (2) Forming papermaking: the PF / SAF / BP mixed slurry obtained in step (1) was formed, dewatered, and dried on a gap former paper machine at a slurry concentration of 1.4 wt% to obtain paper sample I.

[0074] (3) Preparation of barrier coating: 2 g of montmorillonite was placed in a beaker containing 30 g of deionized water, stirred and dispersed, and placed in an ultrasonic vibration disperser for ultrasonic dispersion for 25 min to obtain a montmorillonite suspension; 6 g of polyvinyl alcohol (molecular weight 1.36 x 10 5 ) was placed in a beaker containing 60 g of deionized water, placed in a water bath, first stirred at low speed at room temperature, and then stirred at high speed at 95 ℃ until the polyvinyl alcohol was completely dissolved. Then the prepared montmorillonite suspension was added, 3.5 ml of glycerol was added for plasticization, 1.0 ml of tributyl phosphate was added for defoaming, and after sufficient reaction, 0.05 g of sodium tetraborate was slowly added to the solution. The water bath temperature was adjusted to 75 ℃ and stirred at low speed for 50 min, then cooled to room temperature, and left to stand for 16 h to defoam, to obtain the barrier coating required for the experiment.

[0075] (4) Coating treatment: the barrier coating material obtained in step (3) was diluted with water and coated on both sides of the paper sample I obtained in step (2), wherein the concentration of the barrier coating was 1.2 wt%, the coating speed was 20 m / min, and the single-sided coating amount was 1.9 g / m2 After the double-side coating is completed, the coated paper sample is dried by infrared ray at 100 ℃ for 24 min to obtain paper sample II.

[0076] (5) Post-processing: the paper sample II obtained in step (4) is subjected to hydrothermal pressure treatment at a temperature of 100 ℃ and a pressure of 22 MPa for 13 min, and then is subjected to infrared drying at 43 ℃ for 55 min to obtain high-performance kraft paper.

[0077] The performance indicators of the high-performance kraft paper prepared in this example are as follows: basis weight: 39 g / m 2 ; tensile strength: 3.14 kN / m; tear strength: 752.3 mN; oxygen transmission rate: 386 cm 3 / m 2 ·day·0.1 MPa; water vapor transmission rate: 113 g / m 2 ·day; antibacterial rate on Escherichia coli is 95.7%; antibacterial rate on Staphylococcus aureus is 94.2%.

[0078] Example 3

[0079] This example provides a method for preparing high-performance kraft paper, and the specific preparation steps are as follows:

[0080] (1) Slurry compounding: the bleached kraft pine fiber (PF, length of 2-15 mm, diameter of 22-48 μm) is subjected to beating treatment in a Valmet beater, the beating revolution is 11000 revolutions, the beating consistency is 2.8 wt%, and the beating degree is 65°SR; and the bamboo fiber (SAF, length of 3-9 mm, diameter of 26-37 μm) is also subjected to beating treatment in a Valmet beater, the beating revolution is 7500 revolutions, the beating consistency is 1.7 wt%, and the beating degree is 47°SR. Then the bleached kraft pine fiber after beating is dispersed in a cell disrupter at a speed of 7000 r / min for 18 min at a concentration of 1.4% by mass percentage, and the bamboo fiber after beating is dispersed in a cell disrupter at a speed of 4500 r / min for 9 min at a concentration of 1.5% by mass percentage. Finally, the bleached kraft pine fiber dispersion liquid and the bamboo fiber dispersion liquid obtained after dispersion treatment are uniformly mixed at an absolute dry mass ratio of 6:3 to obtain PF / SAF compounded slurry; under the condition of high-speed stirring (speed: 7000 r / min), nano bamboo powder (BP) (particle diameter of 30-300 nm) is added to the PF / SAF compounded slurry, and the addition amount of the bamboo powder (BP) is 4.0% of the absolute dry mass of the PF / SAF / BP mixed slurry, and the mixture is uniformly mixed to prepare PF / SAF / BP mixed slurry.

[0081] (2) Forming paper: the PF / SAF / BP mixed slurry obtained in step (1) is formed into a sheet, dewatered, and dried on a gap former paper machine at a slurry concentration of 1.5 wt% to obtain a paper sample I.

[0082] (3) Preparation of barrier coating: 3 g of montmorillonite is put into a beaker containing 30 g of deionized water, stirred and dispersed, and placed in an ultrasonic vibration disperser for ultrasonic dispersion for 30 min to obtain a montmorillonite suspension; 7 g of polyvinyl alcohol (molecular weight 1.36 x 10 5 ) is weighed into a beaker containing 60 g of deionized water, placed in a water bath, stirred at low speed at room temperature, and stirred at high speed at 90 ℃ until the polyvinyl alcohol is completely dissolved, then the prepared montmorillonite suspension is added, 4.0 ml of glycerol is added for plasticization, 1.5 ml of tributyl phosphate is added for defoaming, and after sufficient reaction, 0.06 g of sodium tetraborate is slowly added to the solution, the water bath temperature is adjusted to 82 ℃ and stirred at low speed for 55 min, then cooled to room temperature, and allowed to stand for 16 h to defoam, to obtain the barrier coating required for the experiment.

[0083] (4) Coating treatment: the barrier coating material obtained in step (3) is diluted with water and coated onto both sides of the paper sample I obtained in step (2), wherein the barrier coating concentration is 1.4 wt%, the coating speed is 25 m / min, and the single-sided coating amount is 2.2 g / m 2 . After both sides are coated, the coated paper sample is dried by infrared radiation at 110 ℃ for 28 min using an electric infrared generator to obtain a paper sample II.

[0084] (5) Post-treatment: the paper sample II obtained in step (4) is subjected to hydrothermal pressure treatment at a temperature of 105 ℃ and a pressure of 24 MPa for 17 min, and then dried by infrared radiation at 45 ℃ for 65 min to obtain a high-performance kraft paper.

[0085] The performance indicators of the high-performance kraft paper prepared in this example are as follows: basis weight: 41 g / m 2 ; tensile strength: 3.45 kN / m; tear strength: 771.6 mN; oxygen transmission rate: 335 cm 3 / m 2 ·day·0.1 MPa; water vapor transmission rate: 102 g / m 2 ·day; antibacterial rate against Escherichia coli is 97.1%; antibacterial rate against Staphylococcus aureus is 96.3%.

[0086] Example 4

[0087] This example provides a method for preparing a high-performance kraft paper, and the specific preparation steps are as follows:

[0088] (1) Slurry compounding: bleached kraft pine fibers (PF, length 2-15 mm, diameter 22-48 μm) were treated by beating in a Valmet beater, the beating revolutions were 12000, the beating consistency was 3.0 wt%, and the beating degree was 70°SR; and the bamboo fibers (SAF, length 3-9 mm, diameter 26-37 μm) were also treated by beating in a Valmet beater, the beating revolutions were 8000, the beating consistency was 2.0 wt%, and the beating degree was 50°SR. Then the bleached kraft pine fibers after beating were dispersed in a wall-breaking machine at a speed of 8000 r / min for 20 min at a concentration of 1.5 wt%, and the bamboo fibers after beating were dispersed in a wall-breaking machine at a speed of 5000 r / min for 10 min at a concentration of 1.5 wt%. Finally, the bleached kraft pine fiber dispersion and the bamboo fiber dispersion obtained after dispersion were mixed uniformly at a dry mass ratio of 5:2 to obtain a PF / SAF compounded slurry; under the condition of high-speed stirring (speed: 8000 r / min), nano bamboo powder (BP) (particle diameter 30-300 nm) was added to the PF / SAF compounded slurry, the amount of bamboo powder (BP) added was 5.0% of the dry mass of the PF / SAF / BP mixed slurry, and the mixture was uniformly mixed to prepare a PF / SAF / BP mixed slurry.

[0089] (2) Forming papermaking: the PF / SAF / BP mixed slurry obtained in step (1) was formed, dewatered, and dried on a gap former paper machine at a slurry concentration of 1.6 wt% to obtain paper sample I.

[0090] (3) Preparation of barrier coating: 3 g of montmorillonite was placed in a beaker containing 30 g of deionized water, stirred and dispersed, and placed in an ultrasonic vibration disperser for ultrasonic dispersion for 30 min to obtain a montmorillonite suspension; 7 g of polyvinyl alcohol (molecular weight 1.36 x 10 5 ) was placed in a beaker containing 60 g of deionized water, placed in a water bath, first stirred at low speed at room temperature, and then stirred at high speed at 100 ℃ until the polyvinyl alcohol was completely dissolved. Then the prepared montmorillonite suspension was added, 4.5 ml of glycerol was added for plasticization, 1.5 ml of tributyl phosphate was added for defoaming, and after sufficient reaction, 0.07 g of sodium tetraborate was slowly added to the solution. The water bath temperature was adjusted to 85 ℃ and stirred at low speed for 60 min, then cooled to room temperature, and left to stand for 18 h to defoam, to obtain the barrier coating required for the experiment.

[0091] (4) Coating treatment: the barrier coating material obtained in step (3) was diluted with water and coated on both sides of the paper sample I obtained in step (2), wherein the concentration of the barrier coating was 1.5 wt%, the coating speed was 30 m / min, and the single-sided coating amount was 2.5 g / m2 After the double-sided coating is completed, the coated paper sample is dried by infrared ray at 130 ℃ for 30 min to obtain paper sample II.

[0092] (5) Post-processing: the paper sample II obtained in step (4) is subjected to hydrothermal pressure treatment at a temperature of 110 ℃ and a pressure of 25 MPa for 20 min, and then is subjected to infrared drying at 48 ℃ for 80 min to obtain high-performance kraft paper.

[0093] The performance indicators of the high-performance kraft paper prepared in this example are as follows: basis weight: 43 g / m 2 ; tensile strength: 3.67 kN / m; tear strength: 789.2 mN; oxygen transmission rate: 304 cm 3 / m 2 ·day·0.1 MPa; water vapor transmission rate: 96 g / m 2 ·day; antibacterial rate against Escherichia coli is 98.1%; antibacterial rate against Staphylococcus aureus is 98.3%.

[0094] Comparative Example 1

[0095] This comparative example provides a preparation method of kraft paper, and the specific preparation steps are as follows:

[0096] (1) Slurry compounding: the bleached kraft pulp (PF, length of 2-15 mm, diameter of 22-48 μm) is subjected to beating treatment in a valve beater, the beating revolution is 8000 revolutions, the beating concentration is 2.5 wt%, and the beating degree is 55°SR. Then the bleached kraft pulp after beating is dispersed in a wall-breaking machine at a speed of 6000 r / min for 10 min at a concentration of 1.0% by mass. Finally, the bleached kraft pulp dispersion obtained after dispersion is used as PF slurry; under the condition of high-speed stirring (speed: 5000 r / min), nano bamboo powder (BP) (particle diameter of 30-300 nm) is added to the PF slurry, and the addition amount of the bamboo powder (BP) is 2.0% of the absolute dry mass of the PF / BP mixed slurry, and the mixture is uniformly mixed to obtain PF / BP mixed slurry.

[0097] (2) Forming papermaking: the PF / BP mixed slurry obtained in step (1) is formed, dewatered and dried on a gap former paper machine at a slurry concentration of 1.3 wt% to obtain paper sample I.

[0098] (3) Preparation of barrier coating: 1 g of montmorillonite is put into a beaker containing 30 g of deionized water, stirred and dispersed, and then put into an ultrasonic vibration disperser for ultrasonic dispersion for 20 min to obtain a montmorillonite suspension; 5 g of polyvinyl alcohol (molecular weight of 1.36ⅹ105 ) Put into a beaker containing 60 g of deionized water, and put it into a water bath, first at room temperature with low speed stirring, and then at 93℃ with high speed stirring until the polyvinyl alcohol is completely dissolved. Then add the prepared montmorillonite suspension, 3.0 ml of glycerol for plasticization, 1.0 ml of tributyl phosphate for defoaming, and 0.04 g of sodium tetraborate slowly into the solution. After fully reacting, the water bath temperature is adjusted to 80℃ with low speed stirring for 40 min, and then cooled to room temperature. After standing for 12 h to defoam, the barrier coating required for the experiment is obtained.

[0099] (4) Coating treatment: dilute the barrier coating material obtained in step (3) with water and coat it onto both sides of the paper sample I obtained in step (2), with a barrier coating concentration of 1.0 wt%, a coating speed of 15 m / min, and a single-sided coating amount of 1.5 g / m 2 . After both sides are coated, use an electric infrared generator to dry the coated paper sample at 90℃ for 20 min to obtain paper sample II.

[0100] (5) Post-treatment: wet-heat press the paper sample II obtained in step (4) at a temperature of 96℃ and a pressure of 20 MPa for 10 min, and then dry it with infrared rays at 41℃ for 40 min to obtain kraft paper.

[0101] The performance indicators of the kraft paper prepared in this comparative example are as follows: basis weight: 36 g / m 2 ; tensile strength: 2.24 kN / m; tear strength: 615.3 mN; oxygen transmission rate: 876 cm 3 / m 2 ·day·0.1 MPa; water vapor transmission rate: 432 g / m 2 ·day; antibacterial rate against E. coli: 81.5%; antibacterial rate against S. aureus: 79.6%.

[0102] Comparative Example 2

[0103] This comparative example provides a method for preparing kraft paper, and the specific preparation steps are as follows:

[0104] (1) Slurry compounding: bleached kraft pine fibers (PF, length 2-15 mm, diameter 22-48 μm) were treated by beating in a Valmet beater, the beating revolutions were 8000, the beating consistency was 2.5 wt%, and the beating degree was 55°SR; and the bamboo fibers (SAF, length 3-9 mm, diameter 26-37 μm) were also treated by beating in a Valmet beater, the beating revolutions were 6000, the beating consistency was 1.0 wt%, and the beating degree was 40°SR. Then the bleached kraft pine fibers after beating were dispersed in a wall-breaking machine at a speed of 6000 r / min for 10 min at a concentration of 1.0 wt%, and the bamboo fibers after beating were dispersed in a wall-breaking machine at a speed of 3000 r / min for 5 min at a concentration of 1.0 wt%. Finally, the bleached kraft pine fiber dispersion and the bamboo fiber dispersion obtained after dispersion were uniformly mixed at a dry mass ratio of 8:5 to obtain a PF / SAF compound slurry;

[0105] (2) Forming papermaking: the PF / SAF compound slurry obtained in step (1) was formed, dewatered, and dried on a gap former paper machine at a slurry consistency of 1.3 wt% to obtain paper sample I.

[0106] (3) Preparation of barrier coating: 1 g of montmorillonite was placed in a beaker containing 30 g of deionized water, stirred and dispersed, and placed in an ultrasonic vibration disperser for ultrasonic dispersion for 20 min to obtain a montmorillonite suspension; 5 g of polyvinyl alcohol (molecular weight 1.36 x 10 5 ) was placed in a beaker containing 60 g of deionized water, placed in a water bath, stirred at low speed at room temperature, and stirred at high speed at 93 ℃ until the polyvinyl alcohol was completely dissolved, then the prepared montmorillonite suspension was added, 3.0 ml of glycerol was added for plasticization, 1.0 ml of tributyl phosphate was added for defoaming, and after sufficient reaction, 0.04 g of sodium tetraborate was slowly added to the solution, the water bath temperature was adjusted to 80 ℃ and stirred at low speed for 40 min, then cooled to room temperature, and allowed to stand for 12 h to defoam, to obtain the barrier coating required for the experiment.

[0107] (4) Coating treatment: the barrier coating material obtained in step (3) was diluted with water and coated on both sides of the paper sample I obtained in step (2), wherein the use concentration of the barrier coating was 1.0 wt%, the coating speed was 15 m / min, and the single-sided coating amount was 1.5 g / m 2 . After both sides were coated, the coated paper sample was dried by infrared rays at 90 ℃ for 20 min using an electric infrared generator to obtain paper sample II.

[0108] (5) Post-processing: the paper sample II obtained in step (4) is treated by wet heat pressing at a temperature of 96 ℃ and a pressure of 20 MPa for 10 min, followed by infrared drying at 41 ℃ for 40 min, to obtain kraft paper.

[0109] The performance indicators of the kraft paper prepared in this comparative example are as follows: basis weight: 36 g / m 2 ; tensile strength: 2.36 kN / m; tear strength: 634.7 mN; oxygen transmission rate: 936 cm 3 / m 2 ·day·0.1 MPa; water vapor transmission rate: 581 g / m 2 ·day; antibacterial rate against Escherichia coli is 65.3%; antibacterial rate against Staphylococcus aureus is 62.7%.

[0110] Comparative Example 3

[0111] This comparative example provides a method for preparing kraft paper, and the specific preparation steps are as follows:

[0112] (1) Slurry compounding: the bleached kraft pine fibers (PF, length of 2-15 mm, diameter of 22-48 μm) are treated by beating in a Valmet beater, with a beating revolution of 8000, a beating consistency of 2.5 wt%, and a beating degree of 55°SR; and the bamboo fibers (SAF, length of 3-9 mm, diameter of 26-37 μm) are also treated by beating in a Valmet beater, with a beating revolution of 6000, a beating consistency of 1.0 wt%, and a beating degree of 40°SR. Then the bleached kraft pine fibers after beating are dispersed in a cell wall breaker at a speed of 6000 r / min for 10 min at a concentration of 1.0% by mass, and the bamboo fibers after beating are dispersed in a cell wall breaker at a speed of 3000 r / min for 5 min at a concentration of 1.0% by mass. Finally, the bleached kraft pine fiber dispersion obtained after dispersion and the bamboo fiber dispersion are uniformly mixed at an absolute dry mass ratio of 8:5 to obtain PF / SAF compounded slurry; under the condition of high-speed stirring (speed: 5000 r / min), nano bamboo powder (BP) (particle diameter of 30-300 nm) is added to the PF / SAF compounded slurry, and the addition amount of the bamboo powder (BP) is 2.0% of the absolute dry mass of the BF / SF / BP compounded slurry, and the mixture is uniformly mixed to obtain PF / SAF / BP mixed slurry.

[0113] (2) Forming papermaking: the PF / SAF / BP mixed slurry obtained in step (1) is formed, dewatered, and dried on a gap former paper machine at a slurry concentration of 1.3 wt% to obtain paper sample I.

[0114] (3) Post-processing: the paper sample I obtained in step (2) was treated by wet heat pressing at a temperature of 96 ℃ and a pressure of 20 MPa for 10 min, followed by infrared drying at 41 ℃ for 40 min, to obtain kraft paper.

[0115] The performance indicators of the kraft paper prepared in this comparative example are as follows: basis weight: 36 g / m 2 ; tensile strength: 1.97 kN / m; tear strength: 574.3 mN; oxygen transmission rate: 1023 cm 3 / m 2 ·day·0.1 MPa; water vapor transmission rate: 845 g / m 2 ·day; antibacterial rate against Escherichia coli was 60.3%; antibacterial rate against Staphylococcus aureus was 58.7%.

[0116] Comparative Example 4

[0117] This comparative example provides a method for preparing kraft paper, and the specific preparation steps are as follows:

[0118] (1) Slurry compounding: bleached kraft pine fibers (PF, length of 2-10 mm, diameter of 32-45 μm) were treated by beating in a Valmet beater, with a beating revolution of 8000, a beating consistency of 2.5 wt%, and a beating degree of 55°SR; and tree bark fibers (TF, length of 3-15 mm, diameter of 28-40 μm) were also treated by beating in a Valmet beater, with a beating revolution of 6000, a beating consistency of 1.0 wt%, and a beating degree of 40°SR. Then the bleached kraft pine fibers after beating were dispersed in a cell wall breaker at a speed of 6000 r / min for 10 min at a concentration of 1.0% by mass, and the tree bark fibers after beating were dispersed in a cell wall breaker at a speed of 3000 r / min for 5 min at a concentration of 1.0% by mass. Finally, the bleached kraft pine fiber dispersion and the tree bark fiber dispersion obtained after dispersion were uniformly mixed at a dry mass ratio of 8:5 (mass ratio of bleached kraft pine fibers to tree bark fibers) to obtain PF / TF compounded slurry; under the condition of high-speed stirring (speed: 5000 r / min), nano bamboo powder (BP) (particle diameter of 30-300 nm) was added to the PF / TF compounded slurry, and the addition amount of the bamboo powder (BP) was 2.0% of the dry mass of the PF / TF / BP mixed slurry, and the mixture was uniformly mixed to prepare PF / TF / BP mixed slurry.

[0119] (2) Forming papermaking: the PF / TF / BP mixed slurry obtained in step (1) was formed, dewatered, and dried on a Fourdrinier former paper machine at a slurry consistency of 1.3 wt% to obtain paper sample I.

[0120] (3) Barrier coating preparation: Put 1 g of montmorillonite into a beaker containing 30 g of deionized water, stir and disperse, and put into an ultrasonic vibration disperser for ultrasonic dispersion for 20 min to obtain a montmorillonite suspension; weigh 5 g of polyvinyl alcohol (molecular weight 1.36 x 10 5 ) into a beaker containing 60 g of deionized water, put it into a water bath, first stir at room temperature at low speed, and then stir at high speed at 93 ℃ until the polyvinyl alcohol is completely dissolved, then add the prepared montmorillonite suspension, and then add 3.0 ml of glycerol for plasticization, 1.0 ml of tributyl phosphate for defoaming, and fully react, then slowly add 0.04 g of sodium tetraborate into the solution, adjust the water bath temperature to 80 ℃ and stir at low speed for 40 min, then cool to room temperature, and stand for 12 h to defoam, to obtain the barrier coating required for the experiment.

[0121] (4) Coating treatment: dilute the barrier coating material obtained in step (3) with water and coat it onto both sides of the paper sample I obtained in step (2), wherein the use concentration of the barrier coating is 1.0 wt%, the coating speed is 15 m / min, and the single-sided coating amount is 1.5 g / m 2 . After both sides are coated, use an electric infrared generator to dry the coated paper sample at 90 ℃ for 20 min to obtain paper sample II.

[0122] (5) Post-treatment: wet-heat press the paper sample II obtained in step (4) at a temperature of 96 ℃ and a pressure of 20 MPa for 10 min, and then dry it with infrared rays at 41 ℃ for 40 min to obtain kraft paper.

[0123] The performance indicators of the kraft paper prepared in the above comparative example are as follows: basis weight: 36 g / m 2 ; tensile strength: 2.13 kN / m; tear strength: 658.4 mN; oxygen transmission rate: 502 cm 3 / m 2 ·day·0.1 MPa; water vapor transmission rate: 217 g / m 2 ·day; antibacterial rate against E. coli: 78.2%; antibacterial rate against S. aureus: 82.5%.

[0124] The above examples are the preferred embodiments of the present application, but the embodiments of the present application are not limited by the above examples, and any changes, modifications, substitutions, combinations, simplifications made without departing from the spirit and principles of the present application should be equivalent replacement methods, and are all included in the protection scope of the present application.

Claims

1. A method for producing high performance kraft paper, characterized by, It comprises the following steps: (1) pulp compounding: the bleached kraft pulp of wet pine and the bamboo fiber of Neosinocalamus affinis are respectively subjected to beating treatment, then PF dispersion liquid and SAF dispersion liquid are obtained after being dispersed sufficiently, then the PF dispersion liquid and the SAF dispersion liquid are mixed uniformly to obtain PF / SAF compounded pulp, finally the bamboo powder of Neosinocalamus affinis is added into the PF / SAF compounded pulp under stirring to obtain PF / SAF / BP mixed pulp; (2) forming papermaking: the PF / SAF / BP mixed pulp obtained in step (1) is formed into a paper sample I by papermaking, and then the paper sample I is subjected to dehydration and drying treatment; (3) preparation of barrier coating: the montmorillonite is dispersed in water to obtain a montmorillonite suspension; polyvinyl alcohol is added into water, and the temperature is raised to 95±5 ℃ for stirring and dissolving to obtain a polyvinyl alcohol solution; then the polyvinyl alcohol solution is added into the montmorillonite suspension, and glycerol, tributyl phosphate and sodium tetraborate are added, and the temperature is lowered to 80±5 ℃ for stirring and reaction, and then the reaction product is allowed to stand and defoamed to obtain a barrier coating material; (4) coating treatment: the barrier coating material obtained in step (3) is diluted with water, and then coated on both sides of the paper sample I obtained in step (2), and then subjected to infrared drying to obtain a paper sample II; (5) post-treatment: the paper sample II obtained in step (4) is subjected to heat pressing and drying treatment to obtain a high-performance kraft paper; In step (1), the length of the bleached kraft pulp of wet pine is 2-15 mm, and the diameter is 22-48 μm; the length of the bamboo fiber of Neosinocalamus affinis is 3-9 mm, and the diameter is 26-37 μm; In step (1), the absolute dry mass ratio of the bleached kraft pulp of wet pine to the bamboo fiber of Neosinocalamus affinis in the PF / SAF compounded pulp system is 5-8:2-5; In step (1), the addition amount of the bamboo powder of Neosinocalamus affinis is 2.0-5.0 % of the absolute dry mass of the PF / SAF / BP mixed pulp; In step (2), the pulp concentration of the PF / SAF / BP mixed pulp is 1.3-1.6 % by mass; In step (2), the forming papermaking is carried out by using a Fourdrinier former; In step (3), the mass ratio of the montmorillonite to the polyvinyl alcohol is 1-3:5-7; In step (3), the amount of the glycerol is 3-6 % of the total volume of the reaction system; In step (3), the amount of the tributyl phosphate is 1-2 % of the total volume of the reaction system; In step (3), the amount of the sodium tetraborate is 4-7 % of the mass of the montmorillonite; In step (4), the concentration of the barrier coating material is 1.0-1.5 % by mass; The coating conditions in step (4) are as follows: the coating speed is 15 to 30 m / min, and the single-side coating amount is 1.5 to 2.5 g / m 2 ; In step (4), the infrared drying is carried out at 90-130 ℃ for 20-30 min by using an electric infrared generator; In step (5), the heat pressing is carried out at 96-110 ℃ and a pressure of 20-25 MPa for 10-20 min; In step (5), the drying is carried out at 41-48 ℃ for 40-80 min by infrared drying; The bamboo powder in step (1) is a bamboo powder of Dendrocalamopsis oldhami with a particle size of 30-300 nm.

2. The method for preparing high-performance kraft paper according to claim 1, characterized in that: In step (1), the bleached kraft pine fibers are treated by a valve refiner, with a refining revolution of 8000-12000, a refining consistency of 2.5-3.0 wt%, and a refining degree of 55-70°SR; the bamboo fibers are treated by a valve refiner, with a refining revolution of 6000-8000, a refining consistency of 1.0-2.0 wt%, and a refining degree of 40-50°SR. In step (1), the bleached kraft pine fibers are dispersed in a cell wall breaker at a rotation speed of 6000-8000 r / min for 10-20 min at a concentration of 1.0-1.5 wt%; the bamboo fibers are dispersed in a cell wall breaker at a rotation speed of 3000-5000 r / min for 5-10 min at a concentration of 1.0-1.5 wt%.

3. The method for preparing high-performance kraft paper according to claim 1, characterized in that: In step (1), the stirring rotation speed is 5000-8000 r / min; In step (3), the ultrasonic dispersion time is 20-30 min; In step (3), the stirring reaction time is 40-60 min; In step (3), the standing time is 12-18 h.

4. A high performance kraft paper characterized by: The high-performance kraft paper is prepared by any one of the preparation methods in claims 1-3.

5. The use of the high-performance kraft paper in claim 4 in packaging materials.

6. Use according to claim 5, characterized in that: The packaging material is a mildew-resistant and antibacterial packaging material.

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