A method for preparing hydrophobic paper by using a deep eutectic solvent combined with microwave
By combining eutectic solvent and microwave technology with TEMPO oxidation and AlCl3 crosslinking, a hydrophobic paper with high mechanical strength and flexibility was prepared, solving the problem of complex and time-consuming preparation in existing technologies and realizing environmentally friendly and efficient hydrophobic paper production.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- QILU UNIVERSITY OF TECHNOLOGY (SHANDONG ACADEMY OF SCIENCES)
- Filing Date
- 2024-10-14
- Publication Date
- 2026-07-21
AI Technical Summary
Existing superhydrophobic paper manufacturing processes are complex, time-consuming, and costly, and they lose the advantages of wood cell wall structure during the pulping process.
Balsa wood was pretreated using a eutectic solvent combined with microwave technology, followed by TEMPO oxidation and AlCl3 crosslinking. Finally, cellulose paper was prepared by top-down hot pressing and coated with the hydrophobic material HDTMS.
The process achieves the preparation of hydrophobic paper with high mechanical strength and flexibility. It is simple, efficient, environmentally friendly, and has no polymer matrix, while retaining the advantages of wood cell wall structure.
Smart Images
Figure CN119061729B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of new material development technology, and specifically to a method for preparing hydrophobic paper using a eutectic solvent combined with microwaves. Background Technology
[0002] Superhydrophobic paper refers to paper whose surface forms a contact angle greater than 150° and a roll-off angle less than 10° when in contact with water. Using green and renewable hydrophobic paper as packaging material has broad development prospects; furthermore, superhydrophobic paper possesses self-cleaning and anti-corrosion properties, making it highly promising for industrial production.
[0003] Currently, superhydrophobic paper is mainly prepared by coating, spraying, or impregnating low surface energy materials with micro- to nano-structures. For example, patent application number 201210286775.0, "Preparation Method of Superhydrophobic Coating Based on Superhydrophobic Silica and Resin," mentions that resin is coated on a glass slide as a substrate, superhydrophobic silica is adhered to the resin, and the superhydrophobic coating is obtained after the resin cures. However, the resin requires modification treatment, the synthesis process is complex, and the applicable range is narrow, resulting in relatively high overall costs; the preparation process and procedures are also relatively complex, time-consuming, and energy-intensive, and the structural advantages of the wood cell wall structure are lost during the pulping process. Summary of the Invention
[0004] To address the shortcomings of existing technologies, the first objective of this invention is to provide a method for preparing hydrophobic paper using a eutectic solvent combined with microwaves. This invention uses environmentally friendly and renewable balsa wood as raw material. Microwave-assisted heating of a eutectic solvent rapidly removes some lignin from the wood. The resulting sample is then hot-pressed, and a lignin-based cellulose paper is prepared in one step using a top-down method. This method is simple, efficient, convenient, and fast. Finally, a hydrophobic material HDTMS is coated using a CVD method to obtain a cellulose paper-based material with high mechanical strength, good flexibility, hydrophobicity, and no polymer matrix.
[0005] The above-mentioned applications of hydrophobic paper.
[0006] To achieve the above objectives, the present invention adopts the following technical solution:
[0007] A method for preparing hydrophobic paper using a eutectic solvent combined with microwaves, the method comprising the following steps:
[0008] (1) Mix choline chloride and hydrogen bond donor to obtain DES solution;
[0009] (2) Add balsa wood to the DES solution obtained in step (1), heat the reaction, and use the treated balsa wood;
[0010] (3) Soak the balsa wood obtained in step (2) in sodium phosphate (PBS) solvent, add TEMPO, sodium chlorite and sodium hypochlorite PBS solution, stir, and carry out water bath reaction to obtain oxidized balsa wood;
[0011] (4) After cleaning the oxidized balsa wood chips obtained in step (3), soak them in AlCl3 solution and then hot press them to obtain a dense paper sample.
[0012] (5) The paper sample obtained in step (4) is coated with HDTMS (hexadecyltrimethoxysilane) by chemical vapor deposition (CVD) and dried to obtain a hydrophobic paper sample.
[0013] Further, in step (1), the hydrogen bond donor is at least one of oxalic acid, malonic acid, glutaric acid, lactic acid, malic acid and citric acid.
[0014] Further, in step (1), the molar ratio of choline chloride to hydrogen bond donor is 1:(1-3).
[0015] Furthermore, in step (1), the mixing is carried out at 60-120°C.
[0016] Further, in step (2), the solid-liquid mass ratio of the balsa wood and the DES solution is 1:(20-40).
[0017] Furthermore, in step (2), the heating method is microwave heating.
[0018] Furthermore, the microwave heating power is 800-900 W, and the time is 10-40 min.
[0019] Furthermore, in step (2), the heating reaction also requires rinsing the balsa wood with deionized water until the pH of the rinsed liquid is neutral, thus obtaining the treated balsa wood.
[0020] Further, in step (3), the concentration of the sodium phosphate solvent is 0.5-2 M.
[0021] Further, in step (3), the mass-to-volume ratio of the balsa wood, sodium phosphate solvent, TEMPO, sodium chlorite and sodium hypochlorite PBS solution is (0.6-1.5) g : (100-300) mL : (0.02-0.04) g : (1.5-2.5) g : (10-20) mL.
[0022] Furthermore, the concentration of the sodium hypochlorite PBS solution is 0.05-0.2 M.
[0023] Furthermore, the water bath reaction is carried out at a temperature of 60-80°C for a duration of 40-48 hours.
[0024] Furthermore, in step (4), the reagent used for cleaning is deionized water.
[0025] Further, in step (4), the mass fraction of the AlCl3 solution is 1-2 wt%.
[0026] Furthermore, in step (4), the soaking time is 20-30 h.
[0027] Further, in step (4), the pressure of the hot pressing is 0.8-1.5 MPa, the time is 0.5-3 h, and the temperature is 90-100℃.
[0028] Furthermore, in step (5), the drying temperature is 150-165℃ and the time is 2-6 h.
[0029] The hydrophobic paper prepared by the above method.
[0030] The above-mentioned hydrophobic paper can be used in packaging, video, building materials and other fields.
[0031] This invention uses a eutectic solvent of choline chloride and organic carboxylic acids to pretreat balsa wood chips with microwave-assisted heating to remove some lignin. Subsequently, the bonding strength between fibers is further enhanced by TEMPO oxidation and AlCl3 crosslinking. Then, a top-down hot-pressing process is used to obtain a dense cellulose-based paper, in which the neatly arranged cellulose fibers are retained, which helps to form a dense and orderly structure with higher mechanical strength and flexibility than wood with lignin removed.
[0032] Beneficial Effects: This invention utilizes a eutectic solvent combined with microwaves to rapidly remove lignin from plant fiber raw materials. A simple top-down hot-pressing method is then used to prepare dense cellulose paper with excellent mechanical properties. The resulting paper sample is coated with a hydrophobic HDTMS material using CVD. This process is environmentally friendly and eliminates the need for organic solvents, ultimately yielding a hydrophobic paper material with high mechanical strength, good hydrophobic properties, and no polymer matrix. The research and development of this novel cellulose paper material has significant environmental and application prospects and plays a crucial role in enhancing the competitiveness of core technologies in my country's paper industry. Attached Figure Description
[0033] The accompanying drawings, which form part of this specification, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation thereof. Hereinafter, embodiments of the invention will be described in detail with reference to the accompanying drawings.
[0034] Figure 1 These are macroscopic morphology and flexibility diagrams of the hydrophobic paper prepared in Example 1. Figure 1 a is a macroscopic topographic image. Figure 1 b is a diagram demonstrating flexibility;
[0035] Figure 2 These are scanning electron microscope images of the hydrophobic paper prepared in Examples 1 and 4. Figure 2 a is a scanning electron microscope image of the sample from Example 1. Figure 2 b is a scanning electron microscope image of the sample from Example 4;
[0036] Figure 3 Infrared spectra of the hydrophobic paper prepared in Examples 1-4;
[0037] Figure 4 The stress-strain curves of the hydrophobic paper prepared in Examples 1-4 are shown.
[0038] Figure 5 The diagram shows the water contact angles of the hydrophobic paper prepared in Examples 1-4. Figure 5 a is a water contact angle diagram of the hydrophobic paper prepared in Example 1. Figure 5 b is a water contact angle diagram of the hydrophobic paper prepared in Example 2. Figure 5 c is a water contact angle diagram of the hydrophobic paper prepared in Example 3. Figure 5 d represents the water contact angle of the hydrophobic paper prepared in Example 4. Specific Implementation
[0040] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Experimental methods in the following embodiments, unless otherwise specified, are generally performed under conventional conditions or as recommended by the manufacturer.
[0041] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of skill in the art. The reagents and raw materials used in this invention are readily available through conventional means, and unless otherwise specified, they are used in accordance with conventional methods or product instructions. Furthermore, any methods and materials similar to or equivalent to those described herein may be applied to the methods of this invention. The preferred embodiments and materials described herein are for illustrative purposes only. The invention will now be further described with reference to the accompanying drawings and specific embodiments.
[0042] Example 1
[0043] (1) Mix choline chloride and oxalic acid in a molar ratio of 1:1 and stir at 80°C to form a transparent and stable solution to prepare DES solution;
[0044] (2) Add balsa wood (thickness of 5-10 mm) to the DES solution obtained in step (1) at a solid-liquid mass ratio of 1:30, heat with microwave assistance for 10 min, microwave power of 800 W, after the reaction is completed, rinse balsa wood with deionized water until the pH of the rinsed liquid is neutral, and obtain the treated balsa wood.
[0045] (3) The balsa wood obtained in step (2) was soaked in 0.1 M sodium phosphate (PBS) solvent (160 mL, pH 6.8), and then 0.0256 g of TEMPO, 1.808 g of sodium chlorite and 0.1 M sodium hypochlorite PBS solution (16 mL) were added. The mixture was stirred evenly and placed in a 60℃ water bath for 48 h to obtain oxidized balsa wood.
[0046] (4) The oxidized balsa wood chips obtained in step (3) were washed with deionized water and then immersed in 1.5wt% AlCl3 solution for 24 h. The soaked wood chip samples were then hot-pressed at 1 MPa for 1 h at a temperature of 100℃ to obtain dense paper samples.
[0047] (5) The paper sample obtained in step (4) was coated with HDTMS by CVD. The paper sample coated with HDTMS was stored in a glass beaker and placed in an oven and dried at 155°C for 3 h to obtain a hydrophobic paper sample.
[0048] Example 2
[0049] (1) Mix choline chloride and oxalic acid in a molar ratio of 1:1 and stir at 80°C to form a transparent and stable solution to prepare DES solution;
[0050] (2) Add balsa wood (thickness of 5-10 mm) to the DES solution obtained in step (1) at a solid-liquid ratio of 1:30, and heat with microwave assistance for 20 min. The microwave power is 800 W. After the reaction is completed, rinse the balsa wood with deionized water until the pH of the rinsed liquid is neutral to obtain the treated balsa wood.
[0051] (3) The balsa wood obtained in step (2) was soaked in 0.1 M sodium phosphate (PBS) solvent (160 mL, pH 6.8), and then 0.0256 g of TEMPO, 1.808 g of sodium chlorite and 0.1 M sodium hypochlorite PBS solution (16 mL) were added. The mixture was stirred evenly and placed in a water bath at 60 °C for 48 h to obtain oxidized balsa wood chips.
[0052] (4) The oxidized balsa wood chips obtained in step (3) were washed with deionized water and then immersed in 1.5wt% AlCl3 solution for 24 h. The soaked wood chip samples were then hot-pressed at 1 MPa pressure for 1 h at a temperature of 100℃ to obtain a dense paper sample.
[0053] (5) The surface of the dense paper sample obtained in step (4) is coated with HDTMS by CVD method. The paper sample coated with HDTMS is stored in a glass beaker and placed in an oven. It is then dried at 155°C for 3 h to obtain a hydrophobic paper sample.
[0054] Example 3
[0055] (1) Mix choline chloride and oxalic acid in a molar ratio of 1:1 and stir at 80°C to form a transparent and stable solution to prepare DES solution;
[0056] (2) Add balsa wood (thickness of 5-10 mm) to the DES solution obtained in step (1) at a solid-liquid mass ratio of 1:30, heat with microwave assistance for 30 min, microwave power of 900 W, after the reaction is completed, rinse balsa wood with deionized water until the pH of the rinsed liquid is neutral, and obtain the treated balsa wood.
[0057] (3) The balsa wood obtained in step (2) was soaked in 0.1 M sodium phosphate (PBS) solvent (160 mL, pH 6.8), and then 0.0256 g of TEMPO, 1.808 g of sodium chlorite and 0.1 M sodium hypochlorite PBS solution (16 mL) were added. The mixture was stirred evenly and placed in a water bath at 60 °C for 48 h to obtain oxidized balsa wood.
[0058] (4) The oxidized balsa wood chips obtained in step (3) were washed with deionized water and then immersed in 1.5wt% AlCl3 solution for 24 h. The soaked wood chip samples were then hot-pressed at 1 MPa for 1 h at a temperature of 100℃ to obtain dense paper samples.
[0059] (5) The paper sample obtained in step (4) was coated with HDTMS by CVD. The paper sample coated with HDTMS was stored in a glass beaker and placed in an oven and dried at 155°C for 3 h to obtain a hydrophobic paper sample.
[0060] Example 4
[0061] (1) Mix choline chloride and oxalic acid in a molar ratio of 1:1 to prepare a DES solution. Stir at 80°C to form a transparent and stable solution.
[0062] (2) Add balsa wood (thickness of 5-10 mm) to the DES solution obtained in step (1) at a solid-liquid mass ratio of 1:30, and heat with microwave assistance for 40 min. The microwave power is 900 W. After the reaction is completed, rinse the balsa wood with deionized water until the pH of the rinsed liquid is neutral to obtain the treated balsa wood.
[0063] (3) The balsa wood obtained in step (2) was soaked in 0.1 M sodium phosphate (PBS) solvent (160 mL, pH 6.8), and then 0.0256 g of TEMPO, 1.808 g of sodium chlorite and 0.1 M sodium hypochlorite PBS solution (16 mL) were added. The mixture was stirred evenly and placed in a 60℃ water bath for 48 h to obtain oxidized balsa wood.
[0064] (4) The oxidized balsa wood chips obtained in step (3) were washed with deionized water and then immersed in 1.5wt% AlCl3 solution for 24 h. The soaked wood chip samples were then hot-pressed at 1 MPa for 1 h at a temperature of 100℃ to obtain dense paper samples.
[0065] (5) The paper sample obtained in step (4) was coated with HDTMS by CVD. The paper sample coated with HDTMS was stored in a glass beaker and placed in an oven and dried at 155°C for 3 h to obtain a hydrophobic paper sample.
[0066] Comparative Example 1
[0067] (1) Mix choline chloride and oxalic acid in a molar ratio of 1:1 to prepare a DES solution. Stir at 80°C to form a transparent and stable solution.
[0068] (2) Add balsa wood (thickness of 5-10 mm) to the DES solution obtained in step (1) at a solid-liquid mass ratio of 1:30, heat with microwave assistance for 30 min, microwave power of 900 W, after the reaction is completed, rinse balsa wood with deionized water until the pH of the rinsed liquid is neutral, and obtain the treated balsa wood.
[0069] (3) The balsa wood obtained in step (2) was soaked in 0.1 M sodium phosphate solvent (160 mL, pH 6.8), and then 0.0256 g of TEMPO, 1.808 g of sodium chlorite and 16 mL of 0.1 M sodium hypochlorite PBS solution were added. The mixture was stirred evenly and placed in a 60℃ water bath for 48 h to obtain oxidized balsa wood.
[0070] (4) The oxidized balsa wood chips obtained in step (3) are washed with deionized water, and then the washed wood chip samples are hot-pressed at 1 MPa for 1 h at a temperature of 100℃ to obtain dense paper samples.
[0071] (5) The paper sample obtained in step (4) was coated with HDTMS by CVD. The paper sample coated with HDTMS was stored in a glass beaker and placed in an oven and dried at 155°C for 3 h to obtain a hydrophobic paper sample.
[0072] The hydrophobic paper obtained in Comparative Example 1 has a tensile strength of 16.1 MPa and an elongation at break of 2.48%.
[0073] Comparative Example 2
[0074] (1) Add balsa wood (thickness of 5-10 mm) to deionized water at a solid-liquid mass ratio of 1:30, heat with microwave assistance for 30 min, microwave power of 900 W, after the reaction is complete, rinse balsa wood with deionized water until the pH of the rinsed liquid is neutral, and obtain the treated balsa wood.
[0075] (2) The balsa wood obtained in step (1) was soaked in 0.1 M sodium phosphate (PBS) solvent (160 mL, pH 6.8), and then 0.0256 g of TEMPO, 1.808 g of sodium chlorite and 0.1 M sodium hypochlorite PBS solution (16 mL) were added. The mixture was stirred evenly and placed in a 60℃ water bath for 48 h to obtain oxidized balsa wood.
[0076] (3) The oxidized balsa wood chips obtained in step (2) were washed with deionized water, and then immersed in 1.5wt% AlCl3 solution for 24 h. The soaked wood chip samples were then hot-pressed at 1 MPa pressure for 1 h at a temperature of 100℃ to obtain dense paper samples.
[0077] (4) The paper sample obtained in step (3) was coated with HDTMS by CVD. The paper sample coated with HDTMS was stored in a glass beaker and placed in an oven and dried at 155°C for 3 h to obtain a hydrophobic paper sample.
[0078] The hydrophobic paper obtained in Comparative Example 2 has a tensile strength of 18.6 MPa and an elongation at break of 1.94%.
[0079] It is evident from Comparative Examples 1 and 2 that microwave-assisted heating eutectic solvent pretreatment and AlCl3 crosslinking can further improve the mechanical strength and flexibility of hydrophobic paper.
[0080] Performance testing
[0081] Figure 1 The images show the macroscopic morphology and flexibility of the hydrophobic paper prepared in Example 1. Figure 1 a is a macroscopic topographic image. Figure 1 b is a diagram demonstrating the flexibility. The results show that the macroscopic morphology of the hydrophobic paper obtained in Example 1 is dark yellow in color, and it can be wrapped around a pen without breaking, indicating that the cellulose paper has good flexibility.
[0082] Figure 2 These are scanning electron microscope images of the hydrophobic paper prepared in Examples 1 and 4. Figure 2 a is a scanning electron microscope image of the sample from Example 1. Figure 2 b is a scanning electron microscope (SEM) image of the sample from Example 4. Detection method: The sample was placed on a sample stage covered with conductive double-sided adhesive. After gold sputtering using an Oxford Quorum SC7620 sputtering system, the surface morphology of the sample was photographed using a TESCAN MIRA LMS scanning electron microscope. The results showed that the surface roughness of the cellulose paper gradually increased with increasing DES treatment time, indicating that DES treatment can remove lignin and other components from the balsa wood cell walls, resulting in a rough and uneven surface morphology in the image.
[0083] Figure 3 The infrared spectra of the hydrophobic paper prepared in Examples 1-4 are shown. Detection method: Detection was performed using an ALPHA infrared spectrometer in ATR mode. The image shows the 1732cm² value. -1 The absorption peak at 1507 cm⁻¹ corresponds to the stretching vibration peak of C=O in lignin. -1 The absorption peak at the position is the stretching vibration peak of the lignin benzene ring skeleton. It can be seen from the figure that the sample treated with DES still contains a certain amount of lignin, and its peak intensity gradually weakens with the increase of microwave heating time, indicating that the lignin content gradually decreases with the increase of treatment time.
[0084] Figure 4The stress-strain curves of the hydrophobic papers prepared in Examples 1-4 are shown. Testing method: The physical strength properties of the paper were measured using a texture analyzer at a test speed of 19.8 mm / min, and the stress-strain curves were recorded. The tensile strengths of the hydrophobic papers in Examples 1-4 were 25.4 MPa, 20.1 MPa, 17.2 MPa, and 11.3 MPa, respectively, and the elongation at break were 1.86%, 2.25%, 2.78%, and 1.38%, respectively. The results show that the tensile strength gradually decreases with increasing eutectic solvent treatment time; the elongation at break initially increases and then decreases, reaching its highest value after 30 min of microwave reaction, indicating that the hydrophobic paper is more flexible and has better flexibility. This is because the longer the DES treatment time, the more lignin is removed; and lignin has a certain rigidity and adhesiveness. An appropriate amount of lignin can play a reinforcing role in cellulose paper, but excessive lignin will affect the flexibility of the hydrophobic paper.
[0085] Figure 5 The diagram shows the water contact angles of the hydrophobic paper prepared in Examples 1-4. Figure 5 a is a water contact angle diagram of the hydrophobic paper prepared in Example 1. Figure 5 b is a water contact angle diagram of the hydrophobic paper prepared in Example 2. Figure 5 c is a water contact angle diagram of the hydrophobic paper prepared in Example 3. Figure 5 Figure d shows the water contact angle of the hydrophobic paper prepared in Example 4. Detection method: The water contact angle of the samples was measured using a fully automated video optical contact angle meter (OCA50). Cellulose paper samples that had undergone DES microwave heating treatment for 10 min, 20 min, 30 min, and 40 min, respectively, and were then subjected to contact angle testing. The results show that the contact angles of the hydrophobic papers prepared in Examples 1-4 were 101.6°, 101.1°, 99.3°, and 97.8°, respectively. This indicates that the contact angle of the HDTMS-modified hydrophobic paper gradually decreases with increasing DES pretreatment time. This may be because the content of hydrophobic lignin in the cellulose paper gradually decreases with increasing microwave heating pretreatment time, leading to a gradual decrease in the hydrophobic angle.
[0086] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.
Claims
1. A method for preparing hydrophobic paper using a eutectic solvent combined with microwaves, characterized in that, The method includes the following steps: (1) Mix choline chloride and hydrogen bond donor organic carboxylic acid to obtain DES solution; (2) Add balsa wood to the DES solution obtained in step (1), with a solid-liquid mass ratio of balsa wood to DES solution of 1:(20-40), and microwave heat it. The microwave heating power is 700-800 W and the time is 10-20 min to obtain the treated balsa wood. (3) Soak the balsa wood obtained in step (2) in sodium phosphate solvent, add TEMPO, sodium chlorite and sodium hypochlorite PBS solution, stir, and carry out water bath reaction to obtain oxidized balsa wood; (4) After cleaning the oxidized balsa wood chips obtained in step (3), soak them in AlCl3 solution with a mass fraction of 1-2 wt% for 20-30 h, and then hot press them to obtain dense paper samples. (5) The paper sample obtained in step (4) is coated with HDTMS by CVD method and dried to obtain a hydrophobic paper sample.
2. The method according to claim 1, characterized in that, In step (1), the hydrogen bond donor is at least one of oxalic acid, malonic acid, glutaric acid, lactic acid, malic acid and citric acid; The molar ratio of choline chloride to the hydrogen bond donor is 1:(1-3).
3. The method according to claim 1, characterized in that, In step (2), after microwave heating, the balsa wood needs to be rinsed with deionized water until the pH of the rinsed liquid is neutral, thus obtaining the treated balsa wood.
4. The method according to claim 1, characterized in that, In step (3), the concentration of the sodium phosphate solvent is 0.5-2 M; The concentration of the sodium hypochlorite PBS solution is 0.05-0.2 M; The mass-to-volume ratio of the balsa wood, sodium phosphate solvent, TEMPO, sodium chlorite, and sodium hypochlorite PBS solution is (0.6-1.5) g : (100-300) mL : (0.02-0.04) g : (1.5-2.5) g : (10-20) mL; The water bath reaction is carried out at a temperature of 60-80℃ for 40-48 hours.
5. The method according to claim 1, characterized in that, In step (4), the cleaning reagent used is deionized water; The hot pressing pressure is 0.8-1.5 MPa, the time is 0.5-3 h, and the temperature is 90-100℃.
6. The method according to claim 1, characterized in that, In step (5), the drying temperature is 150-165℃ and the time is 2-6 h.
7. The hydrophobic paper prepared by the method according to any one of claims 1-6.
8. The application of the hydrophobic paper according to claim 7, characterized in that, The hydrophobic paper is used in the packaging and building materials industries.