High-strength high-air-permeability germinable seed paper and preparation method thereof

Abstract

The invention discloses high-strength high-air-permeability germinable seed paper and a preparation method thereof, and belongs to the technical field of seed paper preparation. The technical problem that the water absorption and air permeability of traditional seed paper are reduced due to addition of a chemical reinforcing agent, and then the germination rate of seeds is affected is solved. According to the technical scheme, unbleached softwood pulp is used as a raw material, after being pulped by a PFI mill, the unbleached softwood pulp is mixed with cationic lignocellulose nanofibrils and seeds which account for 4-8% of the mass of absolute dry pulp for pulping, forming is conducted through an automatic paper making system of a Kaiser method, and drying and shaping are conducted at the temperature of 40 DEG C; the cationic lignocellulose nanofibrils are prepared by the steps of grinding unbleached softwood pulp, performing alkali treatment, performing etherification reaction and performing ultrahigh-pressure homogenization. The seed paper does not need a chemical reinforcing agent, the air permeability is 17.4-18.8 [mu] m / (Pa.S), the tensile strength is 6.08-6.84 kN / m, and the relative absorptivity is 214-230%.

Description

Technical Field

[0001] This invention relates to the field of seed paper preparation technology, specifically to a high-strength, high-permeability germinating seed paper and its preparation method. Background Technology

[0002] Seed paper is a germination-promoting paper product made by mixing seeds into pulp using papermaking technology. Its core application is in the plant seed propagation process, providing a stable growth environment for seeds and promoting germination, growth, and survival. It has become a crucial auxiliary material in modern agricultural production. Furthermore, seed paper can be combined with other paper products such as tickets, signs, and labels to expand product functions and enhance its utilization value.

[0003] Seed germination requires specific humidity and air permeability conditions. If seed paper has poor water absorption and air permeability, it will directly lead to a decrease in seed germination rate. In traditional technology, chemical strengthening agents are usually added to the pulp to enhance the physical strength of seed paper. However, chemical strengthening agents significantly reduce the paper's water absorption and air permeability, creating a contradiction between "strength improvement and ensuring germination conditions." Therefore, developing germinating seed paper that does not require the addition of papermaking chemicals and possesses high strength, high water absorption, and high air permeability is of great significance for promoting the upgrading of seed paper technology and its agricultural applications. Summary of the Invention

[0004] The primary objective of this invention is to provide a high-strength, high-breathability germinating seed paper that solves the problems of poor water absorption and air permeability and low seed germination rate caused by the addition of chemical reinforcing agents in traditional seed paper. Another objective of this invention is to provide a method for preparing the above-mentioned seed paper, so as to achieve environmentally friendly and efficient large-scale production.

[0005] The technical solution adopted by this invention to solve its technical problem is: a high-strength, high-permeability germinating seed paper, comprising a pulp base and seeds uniformly dispersed in the pulp base; the pulp base is made of unbleached softwood pulp mixed with cationic lignocellulose nanofibers, wherein the cationic lignocellulose nanofibers account for 4-8% of the oven-dry pulp mass, and the basis weight of the seed paper is 110 g / m³. 2 .

[0006] A method for preparing the high-strength, high-permeability, germinating seed paper includes the following steps: S1: Pulping treatment: PFI mill is used to pulp the unbleached softwood pulp, and the pulp concentration is controlled at 10% and the freeness is 50~70°SR; S2: Pulp preparation: Mix the cationic lignocellulose nanofibers with the pulp treated in step S1, then sprinkle in the seeds, and use a debonding machine to stir at a speed of 3000~5000r to make the pulp, cationic lignocellulose nanofibers and seeds evenly mixed. S3: Paper forming: The pulp from step S2 is formed using a Kaiser process automatic paper forming system. Most of the moisture is removed by vacuuming, and the paper is formed. S4: Drying and storage: Place the paper formed in step S3 in a dehumidifying heating room at 40℃ to dry and set its shape, and collect and store it after drying; The cationic lignocellulose nanofibers described in step S2 are prepared by the following method: a. Refining: Unbleached softwood pulp was refined using a PFI mill with a pulping concentration of 10% and a freeness of 90°SR after refining; b. Alkali treatment: Take 1g of oven-dry slurry, add 100ml of 5% NaOH solution, and stir at 300-500rpm for 1-2 hours at room temperature; c. Etherification reaction: Add 2,3-epoxypropyltrimethylammonium chloride dissolved in isopropanol to the system of step b. The mass ratio of 2,3-epoxypropyltrimethylammonium chloride to oven-dry slurry is 3~7 g / g. After mixing, place the mixture in a constant temperature water bath and stir at 30~70℃ for 2~4 h. d. Termination and washing: Add 5-7g of glacial acetic acid to the reaction system in step c to terminate the reaction, and wash the slurry repeatedly with deionized water until the pH of the washing wastewater is 7; e. Ultra-high pressure homogenization: Dilute the slurry washed in step d with deionized water, add it to an ultra-high pressure nanomaterial preparation disperser, adjust the pressure to 25 MPa, cycle and homogenize 15 times, then let it stand for 6-10 hours, collect the lower fiber suspension and store it for later use.

[0007] Specifically, in step c, the mass ratio of 2,3-epoxypropyltrimethylammonium chloride to oven-dried pulp is 5 g / g.

[0008] Specifically, the reaction temperature in step c is 40°C and the reaction time is 3 hours.

[0009] Specifically, the beating degree mentioned in step S1 is 50°SR or 70°SR.

[0010] Specifically, the stirring speed in step b is 300~500 rpm, and the stirring time is 1~2 hours.

[0011] Specifically, the amount of glacial acetic acid added in step d is 7g.

[0012] The beneficial effects of this invention are: Overcoming the contradictions of traditional technologies and ensuring seed germination requirements: This invention abandons the traditional approach of relying on chemical reinforcing agents to improve the strength of seed paper. Through a scientific blend of unbleached softwood pulp and cationic lignocellulose nanofibers, it simultaneously achieves high strength and excellent air permeability and water absorption properties in seed paper without adding any chemical reinforcing agents. This avoids the damage to the seed germination environment caused by chemical agents while providing a stable support structure for the seeds, effectively resolving the core contradiction of "strength improvement and germination condition assurance," ensuring that seeds germinate in a suitable humidity and air permeability environment.

[0013] The materials and processes are green and environmentally friendly, aligning with sustainable development principles: unbleached softwood pulp is used as raw material, reducing the bleaching process in paper production and minimizing chemical pollution; the preparation of cationic lignocellulose nanofibers employs gentle processes such as alkali treatment and etherification reaction, and multiple washing steps remove byproducts and unreacted reagents, resulting in a final product with no harmful residues and no pollution to soil or seeds. The overall preparation process avoids high-pollution and high-energy-consumption stages, meeting the requirements of modern agricultural green development and environmental protection.

[0014] With stable and reliable overall performance, seed paper is suitable for seedling cultivation scenarios: It possesses excellent dry tensile strength as well as good wet tensile strength, making it resistant to damage after contact with water during seedling cultivation, thus providing a stable growth medium for seeds. Simultaneously, its excellent air permeability and water absorption properties allow for rapid response to the water requirements of seed germination and ensure adequate airflow for root respiration. Furthermore, high-speed mixing via a de-leveraging machine ensures uniform seed dispersion in the pulp, preventing seed clumping, guaranteeing stable and uniform germination rates, and reducing replanting costs during the seedling cultivation process.

[0015] The process is highly controllable and facilitates large-scale production: the preparation process parameters of this invention are clearly defined (such as pulping concentration, homogenization pressure, drying temperature, etc.), and the key equipment (PFI mill, Kaiser process automatic papermaking system, ultra-high pressure nanomaterial preparation disperser) are all mature equipment in the industry, requiring no special customization and easily achieving standardized operation. Whether it is the preparation of cationic lignocellulose nanofibers or the papermaking of seed paper, the process is continuous and highly stable, which can meet the needs of large-scale industrial production, laying the foundation for the agricultural promotion and commercial application of seed paper.

[0016] Convenient storage and transportation, extending product lifespan: The formed seed paper is dried and shaped at a low temperature of 40℃, effectively preserving seed activity. Furthermore, after drying, it is stored in a sealed, refrigerated container to prevent premature germination due to changes in environmental temperature and humidity during storage and transportation, significantly extending the shelf life of the seed paper. This characteristic facilitates long-distance transportation and long-term storage of the seed paper, enhancing the product's market circulation and practical value, and is particularly well-suited to the supply chain needs of modern large-scale seedling cultivation. Attached Figure Description

[0017] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0018] Figure 1 The flowchart illustrates a method for preparing high-strength, high-permeability, germinating seed paper provided by this invention. Detailed Implementation

[0019] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below in conjunction with specific embodiments.

[0020] The present invention discloses a high-strength, high-permeability, germinating seed paper comprising a pulp base and seeds uniformly dispersed in the pulp base. The pulp base is primarily composed of unbleached softwood pulp, compounded with cationic lignocellulose nanofibers (accounting for 4-8% of the oven-dry pulp mass), and the seed paper basis weight is controlled at 110 g / m³. 2 This ensures that the paper thickness and density are suitable for the seed germination requirements.

[0021] like Figure 1 As shown, the preparation method of a high-strength, high-permeability germinating seed paper according to the present invention includes the following steps: S1: Pulping Treatment. Unbleached softwood pulp was used as raw material and pulped using a PFI mill. The pulp concentration was controlled at 10% (mass ratio of oven-dry pulp to water), and the freeness was adjusted to 50-70°SR. This step mechanically breaks down the fiber structure, increases the fiber specific surface area, and lays the foundation for subsequent bonding with cationic lignocellulose nanofibers and improved paper strength.

[0022] S2: Add cationic lignocellulose nanofibers at 4-8% of the oven-dry pulp mass and mix with the pulp treated in step S1; then sow the seeds to be cultivated (the amount of seeds is adjusted according to actual needs to ensure that the number of seeds per square meter of paper is uniform); use a de-stirring machine to fully stir at 3000-5000 rpm to make the pulp, cationic lignocellulose nanofibers and seeds completely integrated, avoid seed agglomeration and ensure that they are evenly dispersed in the pulp.

[0023] S3: Papermaking is performed using a Kaiser process automated papermaking system to form paper from the pulp prepared in step S2. The system's built-in vacuum device quickly removes most of the moisture from the pulp (residual moisture content controlled at 20-30%), allowing the pulp fibers to bind tightly with the seeds, forming a pre-formed sheet.

[0024] S4: Drying and Storage. Transfer the paper after shaping in step S3 to a dehumidifying and heating chamber, controlling the temperature to be constant at 40℃ and the relative humidity below 30%. Remove residual moisture from the paper by slow drying at low temperature (drying time is about 2~3 hours) (final moisture content ≤8%) to avoid high temperature damaging seed activity. After drying, cut the paper to the required size, seal and refrigerate (temperature 0~5℃) to prevent premature seed germination.

[0025] Preparation of cationic lignocellulose nanofibers The key reinforcing material in step S2—cationic lignocellulose nanofibers—is prepared through the following steps: a. Pulping pretreatment: Unbleached softwood pulp was pulped using a PFI mill with a pulping concentration of 10% and a freeness of 90°SR after pulping to fully refine the fibers and provide reaction sites for subsequent chemical modification. b. Alkali treatment: Take 1g of oven-dry pulp (the oven-dry weight of the pulp after grinding is calculated), add 100ml of 5% NaOH solution, and stir at room temperature (20~25℃) using a magnetic stirrer at 300~500rpm for 1~2h. NaOH solution can break the hydrogen bonds between fibers, remove some hemicellulose, and increase the number of hydroxyl groups on the fiber surface; c. Etherification reaction: 2,3-epoxypropyltrimethylammonium chloride (EPTMAC) dissolved in isopropanol is added to the above-mentioned alkali treatment system, with the mass ratio of EPTMAC to oven-dry pulp being 3~7 g / g (preferably 5 g / g); after thorough mixing, the fiber suspension is transferred to a round-bottom flask, placed in a constant-temperature water bath, and stirred at 30~70℃ (preferably 40℃) for 2~4 h (preferably 3 h). In this step, the epoxy groups of EPTMAC react with the hydroxyl groups on the fiber surface to achieve cationization modification of the fiber; d. Termination and washing: Add 5-7g of glacial acetic acid (preferably 7g) to the reaction system to neutralize excess NaOH and terminate the etherification reaction; then wash the slurry repeatedly with deionized water (each wash uses 5-10 times the volume of the slurry) until the pH of the washing wastewater is 7, to remove reaction byproducts (such as NaCl) and unreacted EPTMAC and NaOH; e. Ultra-high pressure homogenization: Dilute the washed slurry with deionized water to a concentration of 1-2%, add it to the material tank of an ultra-high pressure nanomaterial dispersing machine; adjust the equipment pressure to 25MPa, turn on the equipment to circulate and homogenize the slurry 15 times, and refine the fibers to the nanoscale through high pressure shearing force; then let the homogenized fiber suspension stand for 6-10 hours, and after the coarse fibers settle, collect the upper stable fiber suspension and refrigerate (0-5℃) for later use to obtain cationic lignocellulose nanofibers.

[0026] The present invention will be further described in detail below with reference to embodiments, but the embodiments of the present invention are not limited thereto. Unless otherwise specified, the reagents, methods and equipment used in the present invention are conventional reagents, methods and equipment in this technical field. Test methods in the following embodiments that do not specify specific experimental conditions are generally performed under conventional experimental conditions. Unless otherwise specified, the reagents and raw materials used in the present invention are commercially available. In the present invention, unless otherwise stated, all percentages (%) are mass percentages (wt%).

[0027] The wood pulp involved in this embodiment of the invention is unbleached softwood pulp; 2,3-epoxypropyltrimethylammonium chloride (EPTMAC) was purchased from Shanghai Maclean Biochemical Technology Co., Ltd.; sodium hydroxide was purchased from Fuchen Chemical Reagent Co., Ltd.; glacial acetic acid and isopropanol were purchased from Shanghai Runjie Chemical Reagent Co., Ltd.

[0028] Example 1: S1: Unbleached softwood pulp is pulped using a PFI mill with a pulping concentration of 10% and a freeness of 50°SR.

[0029] S2: Prepare the pulp by mixing cationic lignocellulose nanofibers with the pulp prepared in step S1. The cationic lignocellulose nanofibers account for 8% of the dry weight of the pulp. Add the seeds and use a desolvator to mix thoroughly at 3000-5000 rpm to integrate the pulp, cationic lignocellulose nanofibers, and seeds.

[0030] S3: Papermaking is carried out. The pulp prepared in step S2 is used for papermaking. The paper basis weight is 110g / m2. The Kaiser process automatic papermaking system is used to vacuum and remove most of the moisture, so that the paper is formed.

[0031] S4: Place the shaped paper obtained in step S3 into a dehumidifying heating chamber at a constant temperature of 40°C to dry and shape the paper. After drying, collect and store the paper. The cationic lignocellulose nanofibers used in step S2 are preferably prepared by the following method: Unbleached softwood pulp was refined using a PFI mill to achieve a pulp concentration of 10% and a freeness of 90%. 1g of pulp (equivalent to oven-dry pulp) was added to 100ml of 5wt% NaOH solution and stirred for 1-2 hours at room temperature and 300-500rpm using a magnetic stirrer. 2,3-epoxypropyltrimethylammonium chloride dissolved in isopropanol was added to the system at a mass ratio of 5g / g of oven-dry pulp. After thorough mixing, the fiber suspension was placed in a round-bottom flask and placed in a constant-temperature water bath at 40℃, where the mixture was stirred for 3 hours. Finally, 7g of glacial acetic acid was added to the flask to terminate the reaction, and the pulp was repeatedly washed with deionized water until the pH of the washing wastewater reached 7 to remove reaction byproducts and unreacted reagents. The reacted pulp was diluted with deionized water and added to the feed tank of an ultra-high pressure nanomaterial dispersant, with the equipment pressure adjusted to approximately 25MPa. Turn on the equipment and circulate the slurry for homogenization about 15 times before collecting the product. Let the fiber suspension stand for about 6-10 hours, then collect the lower layer of fiber suspension and refrigerate it.

[0032] Example 2: S1: Unbleached softwood pulp is pulped using a PFI mill with a pulping concentration of 10% and a freeness of 50°SR.

[0033] S2: Prepare the pulp by mixing cationic lignocellulose nanofibers with the pulp prepared in step S1. The cationic lignocellulose nanofibers account for 6% of the dry weight of the pulp. Add the seeds and use a desolvator to mix thoroughly at 3000-5000 rpm to integrate the pulp, cationic lignocellulose nanofibers, and seeds.

[0034] S3: Papermaking is carried out. The pulp prepared in step S2 is used for papermaking. The paper basis weight is 110g / m2. The Kaiser process automatic papermaking system is used to vacuum and remove most of the moisture, so that the paper is formed.

[0035] S4: Place the shaped paper obtained in step S3 into a dehumidifying heating chamber at a constant temperature of 40°C to dry and shape the paper. After drying, collect and store the paper. The cationic lignocellulose nanofibers used in step S2 are preferably prepared by the following method: Unbleached softwood pulp was refined using a PFI mill to achieve a pulp concentration of 10% and a freeness of 90%. 1g of pulp (equivalent to oven-dry pulp) was added to 100ml of 5wt% NaOH solution and stirred for 1-2 hours at room temperature and 300-500rpm using a magnetic stirrer. 2,3-epoxypropyltrimethylammonium chloride dissolved in isopropanol was added to the system at a mass ratio of 5g / g of oven-dry pulp. After thorough mixing, the fiber suspension was placed in a round-bottom flask and placed in a constant-temperature water bath at 40℃, where the mixture was stirred for 3 hours. Finally, 7g of glacial acetic acid was added to the flask to terminate the reaction, and the pulp was repeatedly washed with deionized water until the pH of the washing wastewater reached 7 to remove reaction byproducts and unreacted reagents. The reacted pulp was diluted with deionized water and added to the feed tank of an ultra-high pressure nanomaterial dispersant, with the equipment pressure adjusted to approximately 25MPa. Turn on the equipment and circulate the slurry for homogenization about 15 times before collecting the product. Let the fiber suspension stand for about 6-10 hours, then collect the lower layer of fiber suspension and refrigerate it.

[0036] Example 3: S1: Unbleached softwood pulp is pulped using a PFI mill with a pulping concentration of 10% and a freeness of 70°SR.

[0037] S2: Prepare the pulp by mixing cationic lignocellulose nanofibers with the pulp prepared in step S1. The cationic lignocellulose nanofibers account for 4% of the dry weight of the pulp. Sprinkle in the seeds and use a desolvator to stir thoroughly at 3000~5000 rpm to integrate the pulp, cationic lignocellulose nanofibers and seeds.

[0038] S3: Papermaking is carried out. The pulp prepared in step S2 is used for papermaking. The paper basis weight is 110g / m2. The Kaiser process automatic papermaking system is used to vacuum and remove most of the moisture, so that the paper is formed.

[0039] S4: Place the shaped paper obtained in step S3 into a dehumidifying heating chamber at a constant temperature of 40°C to dry and shape the paper. After drying, collect and store the paper. The cationic lignocellulose nanofibers used in step S2 are preferably prepared by the following method: Unbleached softwood pulp was refined using a PFI mill to achieve a pulp concentration of 10% and a freeness of 90%. 1g of pulp (equivalent to oven-dry pulp) was added to 100ml of 5wt% NaOH solution and stirred for 1-2 hours at room temperature and 300-500rpm using a magnetic stirrer. 2,3-epoxypropyltrimethylammonium chloride dissolved in isopropanol was added to the system at a mass ratio of 5g / g of oven-dry pulp. After thorough mixing, the fiber suspension was placed in a round-bottom flask and placed in a constant-temperature water bath at 40℃, where the mixture was stirred for 3 hours. Finally, 7g of glacial acetic acid was added to the flask to terminate the reaction, and the pulp was repeatedly washed with deionized water until the pH of the washing wastewater reached 7 to remove reaction byproducts and unreacted reagents. The reacted pulp was diluted with deionized water and added to the feed tank of an ultra-high pressure nanomaterial dispersant, with the equipment pressure adjusted to approximately 25MPa. Turn on the equipment and circulate the slurry for homogenization about 15 times before collecting the product. Let the fiber suspension stand for about 6-10 hours, then collect the lower layer of fiber suspension and refrigerate it.

[0040] Example 4: S1: Unbleached softwood pulp is pulped using a PFI mill with a pulping concentration of 10% and a freeness of 70°SR.

[0041] S2: Prepare the pulp by mixing cationic lignocellulose nanofibers with the pulp prepared in step S1. The cationic lignocellulose nanofibers account for 6% of the dry weight of the pulp. Add the seeds and use a desolvator to mix thoroughly at 3000-5000 rpm to integrate the pulp, cationic lignocellulose nanofibers, and seeds.

[0042] S3: Papermaking is carried out. The pulp prepared in step S2 is used for papermaking. The paper basis weight is 110g / m2. The Kaiser process automatic papermaking system is used to vacuum and remove most of the moisture, so that the paper is formed.

[0043] S4: Place the shaped paper obtained in step S3 into a dehumidifying heating chamber at a constant temperature of 40°C to dry and shape the paper. After drying, collect and store the paper. The cationic lignocellulose nanofibers used in step S2 are preferably prepared by the following method: Unbleached softwood pulp was refined using a PFI mill to achieve a pulp concentration of 10% and a freeness of 90%. 1g of pulp (equivalent to oven-dry pulp) was added to 100ml of 5wt% NaOH solution and stirred for 1-2 hours at room temperature and 300-500rpm using a magnetic stirrer. 2,3-epoxypropyltrimethylammonium chloride dissolved in isopropanol was added to the system at a mass ratio of 5g / g of oven-dry pulp. After thorough mixing, the fiber suspension was placed in a round-bottom flask and placed in a constant-temperature water bath at 40℃, where the mixture was stirred for 3 hours. Finally, 7g of glacial acetic acid was added to the flask to terminate the reaction, and the pulp was repeatedly washed with deionized water until the pH of the washing wastewater reached 7 to remove reaction byproducts and unreacted reagents. The reacted pulp was diluted with deionized water and added to the feed tank of an ultra-high pressure nanomaterial dispersant, with the equipment pressure adjusted to approximately 25MPa. Turn on the equipment and circulate the slurry for homogenization about 15 times before collecting the product. Let the fiber suspension stand for about 6-10 hours, then collect the lower layer of fiber suspension and refrigerate it.

[0044] Example 5: S1: Unbleached softwood pulp is pulped using a PFI mill with a pulping concentration of 10% and a freeness of 60°SR.

[0045] S2: Prepare the pulp by mixing cationic lignocellulose nanofibers with the pulp prepared in step S1. The cationic lignocellulose nanofibers account for 6% of the dry weight of the pulp. Add the seeds and use a desolvator to mix thoroughly at 3000-5000 rpm to integrate the pulp, cationic lignocellulose nanofibers, and seeds.

[0046] S3: Papermaking is carried out. The pulp prepared in step S2 is used for papermaking. The paper basis weight is 110g / m2. The Kaiser process automatic papermaking system is used to vacuum and remove most of the moisture, so that the paper is formed.

[0047] S4: Place the shaped paper obtained in step S3 into a dehumidifying heating chamber at a constant temperature of 40°C to dry and shape the paper. After drying, collect and store the paper. The cationic lignocellulose nanofibers used in step S2 are preferably prepared by the following method: Unbleached softwood pulp was refined using a PFI mill to achieve a pulp concentration of 10% and a freeness of 90%. 1g of pulp (equivalent to oven-dry pulp) was added to 100ml of 5wt% NaOH solution and stirred for 1-2 hours at room temperature and 300-500rpm using a magnetic stirrer. 2,3-epoxypropyltrimethylammonium chloride dissolved in isopropanol was added to the system at a mass ratio of 5g / g of oven-dry pulp. After thorough mixing, the fiber suspension was placed in a round-bottom flask and placed in a constant-temperature water bath at 40℃, where the mixture was stirred for 3 hours. Finally, 7g of glacial acetic acid was added to the flask to terminate the reaction, and the pulp was repeatedly washed with deionized water until the pH of the washing wastewater reached 7 to remove reaction byproducts and unreacted reagents. The reacted pulp was diluted with deionized water and added to the feed tank of an ultra-high pressure nanomaterial dispersant, with the equipment pressure adjusted to approximately 25MPa. Turn on the equipment and circulate the slurry for homogenization about 15 times before collecting the product. Let the fiber suspension stand for about 6-10 hours, then collect the lower layer of fiber suspension and refrigerate it.

[0048] Comparative Example 1 This comparative example follows the preparation method of Example 1, except that cationic lignocellulose nanofibers were not added in step S2.

[0049] Comparative Example 2 This comparative example follows the preparation method of Example 1, except that in step S2, ordinary nanocellulose is added to replace cationic lignocellulose nanofibers.

[0050] Comparative Example 3 This comparative example follows the preparation method of Example 1, except that the unbleached softwood pulp has a freeness of 30°SR.

[0051] Performance testing The seed papers prepared in Examples 1-5 and Comparative Examples 1-3 were tested for air permeability, tensile strength, wet tensile strength, relative absorbency, and seed germination rate, respectively. The test methods are as follows: Air permeability: Tested according to the Schubert method in national standard GB / T 458-2008; Tensile strength: Tested according to GB / T N12914; Wet tensile strength: Tested according to national standard GB / T 465.2; Relative absorbance: Tested according to the national standard GB / T 461.3; Germination rate: The percentage of seeds that germinate under standard seedling conditions.

[0052] The results are shown in Table 1 below: Table 1. Performance analysis of seed paper in examples and comparative examples.

[0053] The test results show that the seed paper prepared in this embodiment of the invention is significantly superior to the comparative example in terms of air permeability, tensile strength, relative absorbency, and germination rate. In particular, the germination rate exceeds 99%, significantly higher than the comparative example without cationic lignocellulose nanofibers or using ordinary nanocellulose, proving that the technical solution of this invention can effectively improve the overall performance of seed paper and meet practical application requirements.

[0054] The implementation of the present invention is not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A high-strength, high-breathability seed paper for germinating seeds, characterized in that, The paper comprises a pulp base and seeds uniformly dispersed in the pulp base; the pulp base is made of unbleached softwood pulp and cationic lignocellulose nanofibers, wherein the cationic lignocellulose nanofibers account for 4-8% of the oven-dry pulp mass, and the basis weight of the seed paper is 110 g / m³. 2 .

2. A method for preparing a high-strength, high-permeability seed paper capable of germinating seeds, characterized in that, Includes the following steps: S1: Pulping treatment: PFI mill is used to pulp the unbleached softwood pulp, and the pulp concentration is controlled at 10% and the freeness is 50~70°SR; S2: Pulp preparation: Mix the cationic lignocellulose nanofibers with the pulp treated in step S1, then sprinkle in the seeds, and use a debonding machine to stir at a speed of 3000~5000r to make the pulp, cationic lignocellulose nanofibers and seeds evenly mixed. S3: Paper forming: The pulp from step S2 is formed using a Kaiser process automatic paper forming system. Most of the moisture is removed by vacuuming, and the paper is formed. S4: Drying and storage: Place the paper formed in step S3 in a dehumidifying heating room at 40℃ to dry and set its shape, and collect and store it after drying; The cationic lignocellulose nanofibers described in step S2 are prepared by the following method: a. Refining: Unbleached softwood pulp was refined using a PFI mill with a pulping concentration of 10% and a freeness of 90°SR after refining; b. Alkali treatment: Take 1g of oven-dry slurry, add 100ml of 5% NaOH solution, and stir at 300-500rpm for 1-2 hours at room temperature; c. Etherification reaction: Add 2,3-epoxypropyltrimethylammonium chloride dissolved in isopropanol to the system of step b. The mass ratio of 2,3-epoxypropyltrimethylammonium chloride to oven-dry slurry is 3~7 g / g. After mixing, place the mixture in a constant temperature water bath and stir at 30~70℃ for 2~4 h. d. Termination and washing: Add 5-7g of glacial acetic acid to the reaction system in step c to terminate the reaction, and wash the slurry repeatedly with deionized water until the pH of the washing wastewater is 7; e. Ultra-high pressure homogenization: Dilute the slurry washed in step d with deionized water, add it to an ultra-high pressure nanomaterial preparation disperser, adjust the pressure to 25 MPa, cycle and homogenize 15 times, then let it stand for 6-10 hours, collect the lower fiber suspension and store it for later use.

3. The method for preparing a high-strength, high-permeability germinating seed paper according to claim 2, characterized in that: The mass ratio of 2,3-epoxypropyltrimethylammonium chloride to oven-dried pulp in step c is 5 g / g.

4. The method for preparing a high-strength, high-permeability germinating seed paper according to claim 2, characterized in that: The reaction temperature in step c is 40°C and the reaction time is 3 hours.

5. The method for preparing a high-strength, high-permeability germinating seed paper according to claim 2, characterized in that: The beating degree mentioned in step S1 is 50°SR or 70°SR.

6. The method for preparing a high-strength, high-permeability germinating seed paper according to claim 2, characterized in that: The stirring speed in step b is 300~500 rpm, and the stirring time is 1~2 hours.

7. The method for preparing a high-strength, high-permeability germinating seed paper according to claim 2, characterized in that: The amount of glacial acetic acid added in step d is 7g.

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