Preparation method of waterproof and oil-proof barrier material and application thereof in waterproof and oil-proof paper

Abstract

The present invention discloses a method for preparing a waterproof and oil-proof barrier material and its application in waterproof and oil-proof paper. The method comprises the following steps: dispersing dried nanocellulose particles in an organic solvent, adding a long-chain alkyltrimethoxysilane modifier thereto, wherein the mass ratio of the nanocellulose particles to the long-chain alkyltrimethoxysilane is 1:1-6, to obtain a liquid A; and compounding the liquid A with ethyl cellulose, wherein the mass ratio of the nanocellulose particles to the ethyl cellulose is 5:1-5, to obtain a waterproof and oil-proof barrier material. When the waterproof and oil-proof barrier material is applied to paper, a layer of nanostructure with good film-forming properties is formed on the surface. This structure can resist the penetration of water and grease, and has excellent waterproof and oil-proof green barrier properties.

Description

Technical Field

[0001] The present invention belongs to the technical field of functional paper, and in particular relates to a preparation method of a waterproof and oil-proof barrier material and an application thereof in waterproof and oil-proof paper. Background Art

[0002] The statements herein merely provide background information related to the present invention and do not necessarily constitute prior art.

[0003] Paper-based packaging materials, due to their lightweight, biodegradable, renewable nature, and mechanical flexibility, are one of the most promising materials for replacing single-use plastics and addressing "white pollution." To date, paper-based packaging accounts for approximately 50% of the packaging industry. However, the hydrophilic and porous nature of paper-based materials' surface fibers results in poor water and oil resistance. Furthermore, the adhesion of water and oil to the paper surface can dramatically degrade the mechanical properties of the paper, severely limiting its daily use. Therefore, improving the water and oil barrier properties of paper-based packaging materials is crucial for further expanding their applications. Applying a polymer coating to the paper surface is one of the simplest and most effective ways to improve its surface water and oil barrier properties. However, current single coatings offer poor water and oil resistance, failing to meet the water and oil resistance requirements of paper-based packaging materials. Therefore, the development of environmentally friendly, water- and oil-resistant paper-based barrier materials has become an urgent need for the paper packaging industry. Summary of the Invention

[0004] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a method for preparing a waterproof and oil-proof barrier material and its application in waterproof and oil-proof paper.

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

[0006] In a first aspect, the present invention provides a method for preparing a waterproof and oil-proof barrier material, comprising the following steps: dispersing dried nanocellulose particles in an organic solvent, and then adding a long-chain alkyltrimethoxysilane modifier thereto, wherein the mass ratio of the nanocellulose particles to the long-chain alkyltrimethoxysilane is 1:1-6, to obtain a liquid A;

[0007] Liquid A is compounded with ethyl cellulose to obtain a mass ratio of nanocellulose particles to ethyl cellulose of 5:1-5.

[0008] Through experiments, the inventors discovered that nanocellulose is a good barrier coating, and its surface contains numerous easily modifiable hydroxyl groups. They formulated a waterproof and oil-resistant barrier material by combining nanocellulose, hydrophobically modified with long-chain alkyltrimethoxysilane, with ethyl cellulose. The low surface energy of the long-chain alkyl groups imparts hydrophobicity to the coating, while the film-forming properties of ethyl cellulose further enhance its oil-repellency. Applying this waterproof and oil-resistant barrier material to paper significantly improves its water and oil resistance, achieving the goal of replacing plastic with paper.

[0009] Furthermore, the use of the waterproof and oil-proof barrier material of the present invention can realize the regulation of the surface properties of paper, so that the coated paper has certain mechanical strength and durability.

[0010] Since nanocellulose is biodegradable and non-toxic, coating hydrophobically modified nanocellulose on the surface of paper to prepare waterproof and oil-proof paper has broad application prospects in the field of replacing plastic and paper packaging.

[0011] In some embodiments, the long-chain alkyltrimethoxysilane modifier is selected from at least one of octadecyltrimethoxysilane, hexadecyltrimethoxysilane, and octadecyltrimethoxysilane.

[0012] In some embodiments, the organic solvent is ethanol. Ethanol is selected as the dispersant and modified solvent system for nanocellulose because nanocellulose can be well dispersed therein, and ethanol is low in toxicity, green, and easily recyclable.

[0013] In some embodiments, the nanocellulose is produced by mechanically grinding bleached softwood pulp after treating it with a cellulose complex enzyme. Bleached softwood pulp has a high aspect ratio and high fiber uniformity, resulting in a highly uniform nanocellulose with improved fiber strength and mechanical properties.

[0014] Preferably, during the enzyme treatment, the slurry concentration is 2%-5%, the slurry pH is 4-6, the temperature is 45-55° C., and the enzyme treatment time is 2-4 h.

[0015] Further preferably, during the enzyme treatment, the slurry concentration is 2.5%-3.5% and the pH value is 4.5-5.5.

[0016] More preferably, during the enzyme treatment, the slurry concentration is 3%, the pH value is 5.0, the temperature is 50° C., and the enzyme treatment time is 3 h.

[0017] In a second aspect, the present invention provides a waterproof and oil-proof barrier material prepared by the preparation method.

[0018] In a third aspect, the present invention provides a waterproof and oil-proof paper comprising a paper substrate and a waterproof and oil-proof coating, wherein the waterproof and oil-proof coating is obtained by coating and curing the waterproof and oil-proof barrier material.

[0019] In a fourth aspect, the present invention provides a method for preparing the waterproof and oil-proof paper, comprising the following steps: coating the waterproof and oil-proof barrier material on a paper substrate, and heating and curing the paper.

[0020] In some embodiments, the temperature of the heat curing is 100-110°C.

[0021] In some embodiments, the coating amount of the waterproof and oil-proof barrier material on the paper substrate is 2-10 g / m 2 .

[0022] Preferably, the coating amount of the waterproof and oil-proof barrier material on the paper substrate is 4-7g / m 2 .

[0023] The coating amount here refers to the coating amount of the solid content of the coating.

[0024] The beneficial effects achieved by one or more embodiments of the present invention are as follows:

[0025] Using nanocellulose prepared by enzyme / mechanical method as raw material, the nanocellulose is hydrophobically modified with silane and compounded with ethyl cellulose to construct a waterproof and oil-proof barrier coating. The hydrophobically modified compounded nanocellulose can be coated on the paper to form a layer of nanostructure with good film-forming properties on the surface. This structure can resist the penetration of water and grease, and has excellent waterproof and oil-proof green and environmentally friendly barrier properties. This waterproof and oil-proof barrier paper has a wider range of application scenarios in the field of plastic substitution.

[0026] The preparation process of nanocellulose is simple and the reaction conditions are mild, making it suitable for large-scale applications.

[0027] The coating amount of waterproof and oil-proof paper is 5g / m 2 When the paper water resistance is 26g / m 2 The oil-proof grade is 10, which has good waterproof and oil-proof performance. The water vapor permeability is 158g / m 2 24h, greatly inhibiting the entry of water vapor into the packaging paper DETAILED DESCRIPTION

[0028] It should be noted that the following detailed description is illustrative and is intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used in the present invention have the same meaning as commonly understood by those skilled in the art to which the present invention belongs.

[0029] The present invention has no special restrictions on the type and source of the cellulose raw materials used. The following uses coniferous wood pulp as an example; the base paper is white food packaging base paper, oil-proof grade 0, Cobb1800 is 100g / m 2 , water vapor permeability is 1293g / m 2 ·24h, water contact angle is 63°, oil contact angle is 19°, and burst resistance index is 6.72kPa·m 2 / g, tear index is 15.76mN·m 2 / g.

[0030] Example 1

[0031] (1) Weigh 500 g of bone-dry softwood pulp and refine it at a concentration of 10%;

[0032] (2) The slurry treated in step (1) was enzymatically hydrolyzed to a slurry concentration of 3%, the amount of cellulose complex enzyme was 10 mg / g, and the slurry was placed in a citric acid-sodium citrate buffer solution with a pH of 5.5, and enzymatically hydrolyzed for 3 hours at 50°C and 100 rpm in a constant temperature shaker;

[0033] (3) subjecting the slurry treated in step (2) to ultrafine grinding at a concentration of 1%;

[0034] (4) dehydrating and drying the nanoparticles obtained in step (3) with ethanol;

[0035] (5) dispersing the nanoparticles obtained in step (4) in 100 g of anhydrous ethanol and adding hexadecyltrimethoxysilane for modification, wherein the mass ratio of the nanoparticles to the hexadecyltrimethoxysilane is 1:5;

[0036] (6) compounding the coating obtained in step (5) with ethyl cellulose to prepare a waterproof and oil-proof coating, wherein the mass ratio of the coating to the ethyl cellulose is 5:1;

[0037] (7) Apply the coating obtained in step (6) to the surface of the paper with a coating amount of 5 g / m 2 , and obtain waterproof and oil-proof paper.

[0038] Result: The obtained waterproof and oil-proof paper has an oil-proof grade of 6 and a Cobb1800 of 81g / m 2 , water vapor permeability is 397g / m 2 ·24h, water contact angle is 92°, oil contact angle is 73°, and burst resistance index is 15.51kPa·m 2 / g, tear index is 17.54mN·m 2 / g.

[0039] Example 2

[0040] (1) Weigh 500 g of bone-dry softwood pulp and refine it at a concentration of 10%;

[0041] (2) The slurry treated in step (1) was enzymatically hydrolyzed to a slurry concentration of 3%, the amount of cellulose complex enzyme was 10 mg / g, and the slurry was placed in a citric acid-sodium citrate buffer solution with a pH of 5.5, and enzymatically hydrolyzed for 3 hours at 50°C and 100 rpm in a constant temperature shaker;

[0042] (3) subjecting the slurry treated in step (2) to ultrafine grinding at a concentration of 1%;

[0043] (4) dehydrating and drying the nanoparticles obtained in step (3) with ethanol;

[0044] (5) dispersing the nanoparticles obtained in step (4) in 100 g of anhydrous ethanol and adding hexadecyltrimethoxysilane for modification, wherein the mass ratio of the nanoparticles to the hexadecyltrimethoxysilane is 1:5;

[0045] (6) compounding the coating obtained in step (5) with ethyl cellulose to prepare a waterproof and oil-proof coating, wherein the mass ratio of the coating to the ethyl cellulose is 5:2;

[0046] (7) Apply the coating obtained in step (6) to the surface of the paper with a coating amount of 5 g / m 2 , and obtain waterproof and oil-proof paper.

[0047] Result: The obtained waterproof and oil-proof paper has an oil-proof grade of 8 and a Cobb1800 of 64g / m 2 , water vapor permeability is 269g / m 2 After 24 hours, the water contact angle is 107°, the oil contact angle is 79°, and the burst resistance index is 15.73 kPa·m 2 / g, tear index is 17.76mN·m 2 / g.

[0048] Example 3

[0049] (1) Weigh 500 g of bone-dry softwood pulp and refine it at a concentration of 10%;

[0050] (2) The slurry treated in step (1) was enzymatically hydrolyzed to a slurry concentration of 3% and a cellulose complex enzyme dosage of 10 mg / g. The slurry was placed in a citric acid-sodium citrate buffer solution with a pH value of 5.5 and enzymatically hydrolyzed for 3 hours at 50°C and 100 rpm in a constant temperature shaker;

[0051] (3) subjecting the slurry treated in step (2) to ultrafine grinding at a concentration of 1%;

[0052] (4) dehydrating and drying the nanoparticles obtained in step (3) with ethanol;

[0053] (5) dispersing the nanoparticles obtained in step (4) in 100 g of anhydrous ethanol and adding hexadecyltrimethoxysilane for modification, wherein the mass ratio of the nanoparticles to the hexadecyltrimethoxysilane is 1:5;

[0054] (6) compounding the coating obtained in step (5) with ethyl cellulose to prepare a waterproof and oil-proof coating, wherein the mass ratio of the coating to the ethyl cellulose is 5:3;

[0055] (7) Apply the coating obtained in step (6) to the surface of the paper with a coating amount of 5 g / m 2 , and obtain waterproof and oil-proof paper.

[0056] Result: The obtained waterproof and oil-proof paper has an oil-proof grade of 10 and a Cobb1800 of 26g / m 2 , water vapor transmission rate is 158g / m 2 24h, water contact angle 90°, oil contact angle 80°, burst resistance index 16.3kPa·m 2 / g, tear index is 17.92mN·m 2 / g.

[0057] Example 4

[0058] (1) Weigh 500 g of bone-dry softwood pulp and refine it at a concentration of 10%;

[0059] (2) The slurry treated in step (1) was enzymatically hydrolyzed to a slurry concentration of 3%, the amount of cellulose complex enzyme was 10 mg / g, and the slurry was placed in a citric acid-sodium citrate buffer solution with a pH of 5.5, and enzymatically hydrolyzed for 3 hours at 50°C and 100 rpm in a constant temperature shaker;

[0060] (3) subjecting the slurry treated in step (2) to ultrafine grinding at a concentration of 1%;

[0061] (4) dehydrating and drying the nanoparticles obtained in step (3) with ethanol;

[0062] (5) dispersing the nanoparticles obtained in step (4) in 100 g of anhydrous ethanol and adding long-chain alkyl groups for modification, wherein the mass ratio of the nanoparticles to hexadecyltrimethoxysilane is 1:5;

[0063] (6) compounding the coating obtained in step (5) with ethyl cellulose to prepare a waterproof and oil-proof coating, wherein the mass ratio of the coating to the ethyl cellulose is 5:4;

[0064] (7) Apply the coating obtained in step (6) to the surface of the paper with a coating amount of 5 g / m 2 , and obtain waterproof and oil-proof paper.

[0065] Result: The obtained waterproof and oil-proof paper has an oil-proof grade of 8 and a Cobb1800 of 48g / m 2 , water vapor permeability is 186g / m 2 After 24 hours, the water contact angle is 123°, the oil contact angle is 82°, and the burst resistance index is 15.91 kPa·m 2 / g, tear index is 17.88mN·m 2 / g.

[0066] Example 5

[0067] (1) Weigh 500 g of bone-dry softwood pulp and refine it at a concentration of 10%;

[0068] (2) The slurry treated in step (1) was enzymatically hydrolyzed to a slurry concentration of 3%, the amount of cellulose complex enzyme was 10 mg / g, and the slurry was placed in a citric acid-sodium citrate buffer solution with a pH of 5.5, and enzymatically hydrolyzed for 3 hours at 50°C and 100 rpm in a constant temperature shaker;

[0069] (3) subjecting the slurry treated in step (2) to ultrafine grinding at a concentration of 1%;

[0070] (4) dehydrating and drying the nanoparticles obtained in step (3) with ethanol;

[0071] (5) dispersing the nanoparticles obtained in step (4) in 100 g of anhydrous ethanol and adding long-chain alkyl groups for modification, wherein the mass ratio of the nanoparticles to hexadecyltrimethoxysilane is 1:5;

[0072] (6) compounding the coating obtained in step (5) with ethyl cellulose to prepare a waterproof and oil-proof coating, wherein the mass ratio of the coating to the ethyl cellulose is 5:5;

[0073] (7) Apply the coating obtained in step (6) to the surface of the paper with a coating amount of 5 g / m 2 , and obtain waterproof and oil-proof paper.

[0074] Result: The obtained waterproof and oil-proof paper has an oil-proof grade of 8 and a Cobb1800 of 51g / m 2 , water vapor permeability is 277g / m 2 ·24h, water contact angle is 133°, oil contact angle is 85°, and burst resistance index is 15.87kPa·m 2 / g, tear index is 17.83mN·m 2 / g.

[0075] Comparative Example 1

[0076] (1) Weigh 500 g of bone-dry softwood pulp and refine it at a concentration of 10%;

[0077] (2) The slurry treated in step (1) was enzymatically hydrolyzed to a slurry concentration of 3%, the amount of cellulose complex enzyme was 10 mg / g, and the slurry was placed in a citric acid-sodium citrate buffer solution with a pH of 5.5, and enzymatically hydrolyzed for 3 hours at 50°C and 100 rpm in a constant temperature shaker;

[0078] (3) subjecting the slurry treated in step (2) to ultrafine grinding at a concentration of 1%;

[0079] (4) dehydrating and drying the nanoparticles obtained in step (3) with ethanol;

[0080] (5) dispersing the nanoparticles obtained in step (4) in 100 g of anhydrous ethanol and adding long-chain alkyl groups for modification, with the mass ratio of the nanoparticles to hexadecyltrimethoxysilane being 1:1;

[0081] (6) Apply the coating obtained in step (5) on the paper surface with a coating amount of 5 g / m 2 , and obtain waterproof and oil-proof paper.

[0082] Result: The obtained waterproof and oil-proof paper has an oil-proof grade of 4 and a Cobb1800 of 92g / m 2 , water vapor permeability is 873g / m 2 ·24h, water contact angle is 75°, oil contact angle is 78°, and burst resistance index is 8.73kPa·m 2 / g, tear index is 15.82mN·m 2 / g.

[0083] Comparative Example 2

[0084] (1) Weigh 500 g of bone-dry softwood pulp and refine it at a concentration of 10%;

[0085] (2) The slurry treated in step (1) was enzymatically hydrolyzed to a slurry concentration of 3%, the amount of cellulose complex enzyme was 10 mg / g, and the slurry was placed in a citric acid-sodium citrate buffer solution with a pH of 5.5, and enzymatically hydrolyzed for 3 hours at 50°C and 100 rpm in a constant temperature shaker;

[0086] (3) subjecting the slurry treated in step (2) to ultrafine grinding at a concentration of 1%;

[0087] (4) dehydrating and drying the nanoparticles obtained in step (3) with ethanol;

[0088] (5) dispersing the nanoparticles obtained in step (4) in 100 g of anhydrous ethanol and adding long-chain alkyl groups for modification, with the mass ratio of the nanoparticles to hexadecyltrimethoxysilane being 1:2;

[0089] (6) Apply the coating obtained in step (5) on the paper surface with a coating amount of 5 g / m 2 , and obtain waterproof and oil-proof paper.

[0090] Result: The obtained waterproof and oil-proof paper has an oil-proof grade of 6 and a Cobb1800 of 88g / m 2 , water vapor transmission rate is 847g / m 2 ·24h, water contact angle is 102°, oil contact angle is 78°, and burst resistance index is 8.77kPa·m 2 / g, tear index is 15.86mN·m 2 / g.

[0091] Comparative Example 3

[0092] (1) Weigh 500 g of bone-dry softwood pulp and refine it at a concentration of 10%;

[0093] (2) The slurry treated in step (1) was enzymatically hydrolyzed to a slurry concentration of 3%, the amount of cellulose complex enzyme was 10 mg / g, and the slurry was placed in a citric acid-sodium citrate buffer solution with a pH of 5.5, and enzymatically hydrolyzed for 3 hours at 50°C and 100 rpm in a constant temperature shaker;

[0094] (3) subjecting the slurry treated in step (2) to ultrafine grinding at a concentration of 1%;

[0095] (4) dehydrating and drying the nanoparticles obtained in step (3) with ethanol;

[0096] (5) dispersing the nanoparticles obtained in step (4) in 100 g of anhydrous ethanol and adding long-chain alkyl groups for modification, wherein the mass ratio of the nanoparticles to hexadecyltrimethoxysilane is 1:3;

[0097] (6) Apply the coating obtained in step (5) on the paper surface with a coating amount of 5 g / m 2 , and obtain waterproof and oil-proof paper.

[0098] Result: The obtained waterproof and oil-proof paper has an oil-proof grade of 6 and a Cobb1800 of 86g / m 2 , water vapor transmission rate is 762g / m 2 ·24h, water contact angle is 110°, oil contact angle is 79°, and burst resistance index is 10.02kPa·m 2 / g, tear index is 15.96mN·m 2 / g.

[0099] Comparative Example 4

[0100] (1) Weigh 500 g of bone-dry softwood pulp and refine it at a concentration of 10%;

[0101] (2) The slurry treated in step (1) was enzymatically hydrolyzed to a slurry concentration of 3%, the amount of cellulose complex enzyme was 10 mg / g, and the slurry was placed in a citric acid-sodium citrate buffer solution with a pH of 5.5, and enzymatically hydrolyzed for 3 hours at 50°C and 100 rpm in a constant temperature shaker;

[0102] (3) subjecting the slurry treated in step (2) to ultrafine grinding at a concentration of 1%;

[0103] (4) dehydrating and drying the nanoparticles obtained in step (3) with ethanol;

[0104] (5) dispersing the nanoparticles obtained in step (4) in 100 g of anhydrous ethanol and adding long-chain alkyl groups for modification, with the mass ratio of the nanoparticles to hexadecyltrimethoxysilane being 1:4;

[0105] (6) Apply the coating obtained in step (5) on the paper surface with a coating amount of 5 g / m 2 , and obtain waterproof and oil-proof paper.

[0106] Result: The obtained waterproof and oil-proof paper has an oil-proof grade of 6 and a Cobb1800 of 81g / m 2 , water vapor permeability is 711g / m 2 After 24 hours, the water contact angle is 131°, the oil contact angle is 78°, and the burst resistance index is 10.44 kPa·m 2 / g, tear index is 15.99mN·m 2 / g.

[0107] Comparative Example 5

[0108] (1) Weigh 500 g of bone-dry softwood pulp and refine it at a concentration of 10%;

[0109] (2) The slurry treated in step (1) was enzymatically hydrolyzed to a slurry concentration of 3%, the amount of cellulose complex enzyme was 10 mg / g, and the slurry was placed in a citric acid-sodium citrate buffer solution with a pH of 5.5, and enzymatically hydrolyzed for 3 hours at 50°C and 100 rpm in a constant temperature shaker;

[0110] (3) subjecting the slurry treated in step (2) to ultrafine grinding at a concentration of 1%;

[0111] (4) dehydrating and drying the nanoparticles obtained in step (3) with ethanol;

[0112] (5) dispersing the nanoparticles obtained in step (4) in 100 g of anhydrous ethanol and adding long-chain alkyl groups for modification, wherein the mass ratio of the nanoparticles to hexadecyltrimethoxysilane is 1:5;

[0113] (6) Apply the coating obtained in step (5) on the paper surface with a coating amount of 5 g / m 2 , and obtain waterproof and oil-proof paper.

[0114] Result: The obtained waterproof and oil-proof paper has an oil-proof grade of 8 and a Cobb1800 of 72g / m 2 , water vapor permeability is 615g / m 2 ·24h, water contact angle is 135°, oil contact angle is 80°, and burst resistance index is 11.34kPa·m 2 / g, tear index is 16.01mN·m 2 / g.

[0115] Comparative Example 6

[0116] (1) Weigh 500 g of bone-dry softwood pulp and refine it at a concentration of 10%;

[0117] (2) The slurry treated in step (1) was enzymatically hydrolyzed to a slurry concentration of 3%, the amount of cellulose complex enzyme was 10 mg / g, and the slurry was placed in a citric acid-sodium citrate buffer solution with a pH of 5.5, and enzymatically hydrolyzed for 3 hours at 50°C and 100 rpm in a constant temperature shaker;

[0118] (3) subjecting the slurry treated in step (2) to ultrafine grinding at a concentration of 1%;

[0119] (4) dehydrating and drying the nanoparticles obtained in step (3) with ethanol;

[0120] (5) dispersing the nanoparticles obtained in step (4) in 100 g of anhydrous ethanol and adding long-chain alkyl groups for modification, with the mass ratio of the nanoparticles to hexadecyltrimethoxysilane being 1:6;

[0121] (6) Apply the coating obtained in step (5) on the paper surface with a coating amount of 5 g / m 2 , and obtain waterproof and oil-proof paper.

[0122] Result: The obtained waterproof and oil-proof paper has an oil-proof grade of 7 and a Cobb1800 of 86g / m 2 , water vapor permeability is 659g / m 2 After 24 hours, the water contact angle is 139°, the oil contact angle is 81°, and the burst resistance index is 10.36 kPa·m 2 / g, tear index is 15.77mN·m 2 / g.

[0123] Comparative Example 7

[0124] (1) Weigh 500 g of bone-dry softwood pulp and refine it at a concentration of 10%;

[0125] (2) The slurry treated in step (1) was enzymatically hydrolyzed to a slurry concentration of 3%, the amount of cellulose complex enzyme was 10 mg / g, and the slurry was placed in a citric acid-sodium citrate buffer solution with a pH of 5.5, and enzymatically hydrolyzed for 3 hours at 50°C and 100 rpm in a constant temperature shaker;

[0126] (3) subjecting the slurry treated in step (2) to ultrafine grinding at a concentration of 1%;

[0127] (4) dehydrating and drying the nanoparticles obtained in step (3) with ethanol;

[0128] (5) compounding the nanoparticles obtained in step (4) with ethyl cellulose to prepare a waterproof and oil-proof coating, wherein the mass ratio of the nanoparticles to the ethyl cellulose is 5:1;

[0129] (6) The coating obtained in step (5) is applied to the surface of paper at a coating amount of 5 g / m2 to obtain waterproof and oil-proof paper.

[0130] Result: The obtained waterproof and oil-proof paper has an oil-proof grade of 7 and a Cobb1800 of 56g / m 2 , water vapor permeability is 501g / m 2 After 24 hours, the water contact angle is 86°, the oil contact angle is 53°, and the burst resistance index is 12.79 kPa·m 2 / g, tear index is 16.04mN·m 2 / g.

[0131] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A waterproof and oil-proof paper, characterized by: It includes a paper substrate and a waterproof and oil-proof coating, wherein the waterproof and oil-proof coating is obtained by coating and curing a waterproof and oil-proof barrier material; The method for preparing the waterproof and oil-proof barrier material comprises the following steps: dispersing dried nanocellulose particles in an organic solvent, adding a long-chain alkyltrimethoxysilane modifier thereto, wherein the mass ratio of the nanocellulose particles to the long-chain alkyltrimethoxysilane is 1:5, to obtain a liquid A; Liquid A was compounded with ethyl cellulose to obtain a mass ratio of nanocellulose particles to ethyl cellulose of 5:1-5; The waterproof and oil-proof barrier material is coated on a paper substrate, and heated and cured to obtain the waterproof and oil-proof paper; The nanocellulose is prepared by treating softwood bleached pulp with a cellulose complex enzyme and then mechanically grinding it; During the enzyme treatment process, the slurry concentration is 2%-5%, the slurry pH is 4-6, the temperature is 45-55°C, and the enzyme treatment time is 2-4h.

2. The waterproof and oil-proof paper according to claim 1, characterized in that: The temperature for heating and curing is 100-110°C.

3. The waterproof and oil-proof paper according to claim 1, characterized in that: The coating amount of waterproof and oil-proof barrier material on the paper substrate is 2-10 g / m 2 .

4. The waterproof and oil-proof paper according to claim 3, characterized in that: The coating amount of waterproof and oil-proof barrier material on the paper substrate is 4-7 g / m 2 .

5. A method for preparing a waterproof and oil-proof barrier material, characterized by: A method for preparing the waterproof and oil-proof coating of the waterproof and oil-proof paper according to claim 1, comprising the steps of: dispersing dried nanocellulose particles in an organic solvent, adding a long-chain alkyltrimethoxysilane modifier thereto, wherein the mass ratio of the nanocellulose particles to the long-chain alkyltrimethoxysilane is 1:5, to obtain a liquid A; Liquid A was compounded with ethyl cellulose to obtain a mass ratio of nanocellulose particles to ethyl cellulose of 5:1-5; The nanocellulose is prepared by treating softwood bleached pulp with a cellulose complex enzyme and then mechanically grinding it; During the enzyme treatment process, the slurry concentration is 2%-5%, the slurry pH is 4-6, the temperature is 45-55°C, and the enzyme treatment time is 2-4h.

6. The method for preparing a waterproof and oil-proof barrier material according to claim 5, characterized in that: The long-chain alkyltrimethoxysilane modifier is selected from at least one of octadecyltrimethoxysilane, hexadecyltrimethoxysilane and octadecyltrimethoxysilane.

7. The method for preparing a waterproof and oil-proof barrier material according to claim 5, characterized in that: The organic solvent is ethanol.

8. The method for preparing a waterproof and oil-proof barrier material according to claim 5, characterized in that: During the enzyme treatment, the slurry concentration is 2.5%-3.5% and the pH value is 4.5-5.

5.

9. The method for preparing a waterproof and oil-proof barrier material according to claim 8, characterized in that: During the enzyme treatment, the slurry concentration was 3%, the pH value was 5.0, the temperature was 50 °C, and the enzyme treatment time was 3 h.

10. A waterproof and oil-proof barrier material, characterized by: The waterproof and oil-proof barrier material is prepared by the preparation method of any one of claims 5 to 9.