A method for preparing a marine antifouling anti-bioadhesion hydrogel microparticle coating

Abstract

This invention discloses a method for preparing a marine antifouling and antibioadhesion hydrogel microparticle coating. First, hydrophilic polymer monomers, nano-clay, and ultrapure water are mixed, and a catalyst and initiator are added and stirred to form a prepolymer solution. This solution is poured into a template for polymerization, and the mixture is then peeled off and cleaned to obtain a composite hydrogel. Next, the hydrogel is pre-frozen, vacuum freeze-dried, pulverized, and ball-milled to produce hydrogel microparticles with uniform particle size. A stainless steel plate is polished, ultrasonically cleaned, and dried, then a bonding layer is brushed on, followed by spraying with the hydrogel microparticles and curing to finally obtain the final product. This invention features a simple process, strong versatility, and no requirements on the substrate material or shape. The coating adhesion strength meets the needs of practical applications. When immersed in seawater, the coating quickly absorbs water to form a superhydrophilic layer, exhibiting excellent superoleophobic properties. Furthermore, the coating shows significant antibacterial adhesion, with a low bacterial adhesion rate, and is free of harmful antifouling agents such as cuprous oxide, making it safe and environmentally friendly, and providing a marine static antifouling effect.

Description

Technical Field

[0001] This invention belongs to the field of marine antifouling materials technology, specifically relating to a method for preparing a marine antifouling and antibioadhesion hydrogel microparticle coating. Background Technology

[0002] Marine fouling organisms (such as diatoms, barnacles, and mussels) readily adhere to ship hulls, buoys, water pipelines, submarine cables, floating bridges, and fish cages, rapidly growing and multiplying to form biofouling. This leads to accelerated wear and tear on marine engineering equipment, causing significant safety hazards and economic losses, and severely hindering the development of the marine economy. Therefore, developing an effective marine antifouling system is of great significance and extremely urgent.

[0003] With the development of marine antifouling technology, antifouling methods with different properties have been continuously developed and applied. Among them, antifouling coatings are widely used as an economical and effective method. Early marine antifouling coatings mainly reduced marine fouling organisms by releasing toxic heavy metals such as arsenic and mercury, but this method also led to the death of other marine life and has therefore been banned. Low-toxicity cuprous oxide self-polishing antifouling coatings have attracted great attention due to their relatively low toxicity and have become the main antifouling coating currently used. However, excessive use of copper can still lead to the death of algae and other organisms, damaging the marine ecosystem, so its use in antifouling coatings is strictly limited. Given the fatal flaws of traditional toxic antifouling coatings, the development of non-toxic antifouling coatings has become a global consensus and goal for researchers, and the development of environmentally friendly and durable antifouling coatings has become a research hotspot.

[0004] In recent years, non-toxic and environmentally friendly antifouling coatings have made breakthrough progress, including dynamically degradable antifouling coatings, natural antifouling agent coatings, and hydrogel antifouling coatings. Among them, the design and development of hydrogel self-cleaning antifouling coatings has provided a new perspective and path for the application of hydrophilic polymers in marine antifouling, demonstrating huge market prospects and application value. Researchers have developed several hydrogel self-cleaning coating products based on the dynamic and static antifouling characteristics of hydrophilic mucus simulating the skin of marine organisms (such as sharks and corals), and have conducted comprehensive real-sea performance evaluations. For example, Professor Zhou Feng's team developed a series of interpenetrating polymer networks (IPNs) with self-secreting properties through free radical polymerization, containing zwitterionic nanoparticles and lubricants, endowing them with quasi-static antifouling and dynamic fouling release properties, giving them broad application value (Chemical Engineering Journal, 2022, 429, 132300). However, hydrogel materials still face technical bottlenecks in long-term applications, such as insufficient hydrophilicity, poor mechanical properties, and weak adhesion to the substrate, which urgently need to be addressed. Summary of the Invention

[0005] The purpose of this invention is to overcome the defects of the prior art and provide a method for preparing a marine antifouling and antibioadhesion hydrogel microparticle coating.

[0006] The technical solution of the present invention is as follows:

[0007] A method for preparing a marine antifouling and antibioadhesion hydrogel microparticle coating includes the following steps:

[0008] (1) The hydrophilic polymer monomer, nano clay and ultrapure water are mixed and fully dissolved to form a uniform mixture. Then, the catalyst N,N,N',N'-tetramethylethylenediamine and the initiator potassium persulfate are added and stirred rapidly to obtain a prepolymer solution. The prepared prepolymer solution is immediately poured into the template for polymerization reaction. Then, it is peeled off from the template and the residual solution is washed away to obtain a composite hydrogel.

[0009] (2) The composite hydrogel obtained in step (1) is pre-frozen, then vacuum freeze-dried, then pre-pulverized, and then ball-milled to obtain hydrogel powder; after sieving, hydrogel microparticles with uniform particle size distribution are obtained.

[0010] (3) Polish the stainless steel plate with sandpaper, then clean it with acetone, ethanol and deionized water in sequence using ultrasonic cleaning, and dry it for later use.

[0011] (4) Prepare a pre-cured bonding layer on the surface of the stainless steel plate after the treatment in step (3);

[0012] (5) The hydrogel microparticles obtained in step (2) are sprayed onto the bonding layer prepared in step (4) and cured at room temperature to obtain the marine antifouling and antibioadhesion hydrogel microparticle coating.

[0013] In a preferred embodiment of the present invention, the hydrophilic polymer monomer is selected from isopropylacrylamide, acrylamide, ethylene glycol, vinyl alcohol, and sodium alginate.

[0014] More preferably, the hydrophilic polymer monomer is isopropylacrylamide or acrylamide.

[0015] In a preferred embodiment of the present invention, the nanoclay is selected from S482, XLG, RD and nanomontmorillonite.

[0016] More preferably, the nano-clay is S482.

[0017] In a preferred embodiment of the present invention, the bonding layer is obtained by brushing, rolling or spraying with Xingang DTM-SS17 varnish, Ergo 7300 epoxy adhesive or Araldite 937308 epoxy adhesive, and its thickness is 0.1-0.3 mm.

[0018] In a preferred embodiment of the present invention, the hydrophilic polymer monomer is isopropylacrylamide or acrylamide, the nano-clay is S482, the connecting layer is obtained by brushing with Xin Gang DTM-SS17 varnish, and the pre-curing time of Xin Gang DTM-SS17 varnish is 1 hour.

[0019] In a preferred embodiment of the present invention, in step (1), the hydrophilic polymer monomer and the nanoclay are 10 wt% and 20 wt% of the ultrapure water, respectively.

[0020] More preferably, in step (1), the amount of catalyst N,N,N',N'-tetramethylethylenediamine and initiator potassium persulfide added is 0.3 wt%.

[0021] In a preferred embodiment of the present invention, in step (2), the pre-freezing temperature is -80°C, the vacuum freeze-drying conditions are -40°C for 48 hours, and the ball milling conditions are ball milling at 1600 r / min for 2 minutes; the continued curing time in step (4) is 2 hours.

[0022] The beneficial effects of this invention are:

[0023] 1. The preparation method of this invention is simple and universally applicable. It has no specific requirements on the material and shape of the substrate, and the resulting marine antifouling and antibioadhesion hydrogel microparticle coating exhibits an adhesion strength greater than 1 MPa on different substrates, meeting the practical application requirements of marine antifouling coatings.

[0024] 2. The marine antifouling and antibioadhesion hydrogel microparticle coating prepared by this invention has good hydrophilicity. When the coating is immersed in seawater, it can quickly absorb water and swell to form a superhydrophilic hydrogel layer.

[0025] 3. The marine antifouling and antibioadhesion hydrogel microparticle coating prepared by the present invention exhibits excellent underwater superoleophobic properties, with an underwater oil droplet contact angle greater than 140°.

[0026] 4. The marine antifouling and antibioadhesion hydrogel microparticle coating prepared by the present invention has a good antibacterial adhesion effect, with a bacterial adhesion rate of less than 40%.

[0027] 5. The marine antifouling and antibioadhesion hydrogel microparticle coating prepared by this invention is safe and environmentally friendly, does not contain harmful antifouling agents such as cuprous oxide, and has excellent marine static antifouling effect. Attached Figure Description

[0028] Figure 1 This is a photograph of the PNIPAM / Clay composite hydrogel prepared in Example 1 of the present invention.

[0029] Figure 2This is a photograph of the marine antifouling and antibioadhesion hydrogel microparticle coating prepared in Example 1 of the present invention.

[0030] Figure 3 This is an optical image of the underwater contact angle of the marine antifouling and antibioadhesion hydrogel microparticle coating prepared in Example 1 of the present invention with oil droplets.

[0031] Figure 4 This is a comparison chart showing the antibacterial adhesion performance of the marine antifouling and antibioadhesion hydrogel microparticle coating (PNIPAM / Clay) prepared in Example 1 of the present invention, the comparative hydrogel microparticle coating (PNIPAM / Agar coating) prepared in Comparative Example 1, and stainless steel as a control.

[0032] Figure 5 The images show the marine antifouling and antibioadhesion hydrogel microparticle coating (left) prepared in Example 1 of this invention and the blank control group (stainless steel, right) on a real seabed. Detailed Implementation

[0033] The technical solution of the present invention will be further explained and described below with reference to specific embodiments and accompanying drawings.

[0034] Example 1

[0035] (1) Isopropylacrylamide monomer (NIPAM), nanoclay (Clay S482), and ultrapure water were mixed and fully dissolved to form a homogeneous mixture. The amounts of NIPAM and S482 added were 10 wt% and 20 wt% of the mass of ultrapure water, respectively. Next, N,N,N',N'-tetramethylethylenediamine (0.3 wt%) as catalyst and potassium persulfide (0.3 wt%) as initiator were added to the mixture, and the mixture was stirred rapidly for approximately 30 seconds to obtain a prepolymer solution. The prepared prepolymer solution was immediately poured into a template for polymerization. After the reaction was complete, the mixture was peeled off from the template, and the residual solution was washed away with pure water to obtain the desired product. Figure 1 The PNIPAM / Clay composite hydrogel shown.

[0036] (2) The PNIPAM / Clay composite hydrogel obtained in step (1) was pre-frozen overnight at -80℃, then placed in a vacuum freeze dryer and dried at -40℃ for 48 hours. It was then pre-crushed using a pulverizer, followed by ball milling at a speed of 1600 r / min for 2 minutes to obtain PNIPAM / Clay hydrogel powder. After sieving, hydrogel microparticles with uniform particle size distribution were obtained.

[0037] (3) Polish the stainless steel plate with sandpaper, then clean it with acetone, ethanol and deionized water in sequence for 5 minutes, and dry it for later use.

[0038] (4) Using a brush coating method, a bonding layer with a thickness of 0.1-0.3 mm is prepared on the surface of the stainless steel plate after the treatment in step (3) (using Xin Gang DTM-SS17 varnish), and the varnish is pre-cured for 1 hour.

[0039] (5) Spray the hydrogel microparticles obtained in step (2) onto the connecting layer prepared in step (4), and continue to cure at room temperature for 2 hours to prepare the product as shown in the figure. Figure 2 The image shows a marine antifouling and antibioadhesion hydrogel microparticle coating.

[0040] The contact angle of the marine antifouling and antibioadhesion hydrogel microparticle coating prepared in this embodiment was tested, and the contact angle of water droplets in the air was 45°.

[0041] A stainless steel plate coated with the marine antifouling and antibioadhesion hydrogel microparticles prepared in this embodiment is immersed in seawater. The hydrogel microparticles absorb water and swell to form a superhydrophilic gel layer that resists bioadhesion.

[0042] Contact angle tests were conducted on the marine antifouling and antibioadhesion hydrogel microparticle coating on the surface of the aforementioned stainless steel plate. The contact angle with water droplets in air was approximately 0°, and the contact angle with oil droplets underwater was approximately 141° (e.g., ...). Figure 3 (As shown).

[0043] Antibacterial tests (E. coli) were conducted on the marine antifouling and antibioadhesion hydrogel microparticle coating on the surface of the above-mentioned stainless steel plate. The results showed that it had good antibacterial adhesion effect, with an anti-adhesion rate greater than 56% (e.g., E. coli). Figure 4 (As shown).

[0044] The marine antifouling and antibioadhesion hydrogel microparticle coating prepared in this embodiment was placed in the sea area of ​​Dalipu Island, Xiamen, and immersed for 5 days and 30 days, respectively. The results are as follows: Figure 5 As shown, a small number of round barnacles and slender limestone worms adhered to the coating surface, but no corrosion was observed. The biofouling area was less than 25%, demonstrating excellent anti-biofouling performance.

[0045] Example 2

[0046] (1) Acrylamide monomer (AM), nanoclay (Clay S482), and ultrapure water were mixed and fully dissolved to form a homogeneous mixture. The amounts of AM and S482 added were 10 wt% and 20 wt% of the mass of ultrapure water, respectively. Next, N,N,N',N'-tetramethylethylenediamine (0.3 wt%) as a catalyst and potassium persulfide (0.3 wt%) as an initiator were added to the mixture, and the mixture was stirred rapidly for approximately 30 seconds to obtain a prepolymer solution. The prepared prepolymer solution was immediately poured into a template for polymerization. After the reaction was complete, the mixture was peeled off from the template, and the residual solution was washed away with pure water to obtain a PAM / Clay composite hydrogel.

[0047] (2) The PAM / Clay composite hydrogel obtained in step (1) was pre-frozen overnight at -80℃, then placed in a vacuum freeze dryer and dried at -40℃ for 48 hours. It was then initially pulverized using a pulverizer, followed by ball milling at a speed of 1600 r / min for 2 minutes to obtain PAM / Clay hydrogel powder. After sieving, hydrogel microparticles with uniform particle size distribution were obtained.

[0048] (3) Polish the stainless steel plate with sandpaper, then clean it with acetone, ethanol and deionized water in sequence for 5 minutes, and dry it for later use.

[0049] (4) Using a brush coating method, a bonding layer with a thickness of 0.1-0.3 mm is prepared on the surface of the stainless steel plate after the treatment in step (3) (using Xin Gang DTM-SS17 varnish), and the varnish is pre-cured for 1 hour.

[0050] (5) Spray the hydrogel microparticles obtained in step (2) onto the connecting layer prepared in step (4), and continue to cure at room temperature for 2 hours to prepare a marine antifouling and antibioadhesion hydrogel microparticle coating.

[0051] The contact angle of the marine antifouling and antibioadhesion hydrogel microparticle coating prepared in this embodiment was tested, and the contact angle of water droplets in air was 30°.

[0052] The stainless steel plate with a marine antifouling and antibioadhesion hydrogel microparticle coating obtained in this embodiment was immersed in seawater. The hydrogel microparticles absorbed water and swelled to form a superhydrophilic gel layer that resists bioadhesion.

[0053] The contact angle of the marine antifouling and antibioadhesion hydrogel microparticle coating on the surface of the above stainless steel plate was tested. The contact angle of water droplets in air was about 0°, and the contact angle of oil droplets underwater was about 140°.

[0054] Antibacterial tests (E. coli) were conducted on the marine antifouling and antibioadhesion hydrogel microparticle coating on the surface of the above stainless steel plate. The results showed that it had a good antibacterial adhesion effect with an anti-adhesion rate of more than 55%.

[0055] The marine antifouling and antibioadhesion hydrogel microparticle coating prepared in this embodiment was placed in the sea area of ​​Dalipu Island, Xiamen, and immersed for 5 days and 30 days, respectively. The results are as follows: Figure 5 As shown, a small number of round barnacles and slender limestone worms adhered to the coating surface, but no corrosion was observed. The biofouling area was less than 25%, demonstrating excellent anti-biofouling performance.

[0056] Comparative Example 1

[0057] (1) Acrylamide monomer (NIPAM), agar, and ultrapure water were mixed and fully dissolved to form a homogeneous mixture. The amounts of NIPAM and agar added were 10 wt% and 1 wt% of the mass of ultrapure water, respectively. Next, N,N,N',N'-tetramethylethylenediamine (0.3 wt%) as a catalyst and potassium persulfide (0.3 wt%) as an initiator were added to the mixture, and the mixture was stirred rapidly for approximately 30 seconds to obtain a prepolymer solution. The prepared prepolymer solution was immediately poured into a template for polymerization. After the reaction was complete, the mixture was peeled off from the template, and the residual solution was washed away with pure water to obtain the PNIPAM / Agar composite hydrogel.

[0058] (2) The PNIPAM / Agar composite hydrogel obtained in step (1) was pre-frozen overnight at -80℃, then placed in a vacuum freeze dryer and dried at -40℃ for 48 hours. It was then initially pulverized using a pulverizer, followed by ball milling at a speed of 1600 r / min for 2 minutes to obtain PNIPAM / Agar hydrogel powder. After sieving, hydrogel microparticles with uniform particle size distribution were obtained.

[0059] (3) Polish the stainless steel plate with sandpaper, then clean it with acetone, ethanol and deionized water in sequence for 5 minutes, and dry it for later use.

[0060] (4) Using a brush coating method, a bonding layer with a thickness of 0.1-0.3 mm is prepared on the surface of the stainless steel plate after the treatment in step (3) (using Xin Gang DTM-SS17 varnish), and the varnish is pre-cured for 1 hour.

[0061] (5) Spray the hydrogel microparticles obtained in step (2) onto the connecting layer prepared in step (4), and continue to cure at room temperature for 2 hours to prepare a comparative hydrogel microparticle coating.

[0062] The contact angle of the comparative hydrogel microparticle coating prepared in this comparative example was tested, and the contact angle of the water droplet in the air was 50°.

[0063] When the stainless steel plate with the comparative hydrogel microparticle coating obtained in this comparative example was immersed in seawater, the hydrogel microparticles absorbed water and swelled to form a superhydrophilic gel layer.

[0064] Contact angle tests were performed on the comparative hydrogel microparticle coating on the surface of the stainless steel plate. The contact angle of the coating with water droplets in air was approximately 0°, and the contact angle of the coating with oil droplets underwater was approximately 135°.

[0065] Antibacterial tests (E. coli) were performed on the comparative hydrogel microparticle coating on the surface of the above stainless steel plate, and the results are as follows: Figure 4 As shown, its antibacterial adhesion effect is poor, with an anti-adhesion rate of approximately -850%.

[0066] Comparative Example 2

[0067] (1) Isopropylacrylamide monomer (NIPAM), nanoclay (Clay S482), and ultrapure water were mixed and fully dissolved to form a homogeneous mixture. The amounts of NIPAM and S482 added were 10 wt% and 20 wt% of the mass of ultrapure water, respectively. Next, N,N,N',N'-tetramethylethylenediamine (0.3 wt%) as catalyst and potassium persulfide (0.3 wt%) as initiator were added to the mixture, and the mixture was stirred rapidly for approximately 30 seconds to obtain a prepolymer solution. The prepared prepolymer solution was immediately poured into a template for polymerization. After the reaction was complete, the mixture was peeled off from the template, and the residual solution was washed away with pure water to obtain the desired product. Figure 1 The PNIPAM / Clay composite hydrogel shown.

[0068] (2) The PNIPAM / Clay composite hydrogel obtained in step (1) was pre-frozen overnight at -80℃, then placed in a vacuum freeze dryer and dried at -40℃ for 48 hours. It was then pre-crushed using a pulverizer, followed by ball milling at a speed of 1600 r / min for 2 minutes to obtain PNIPAM / Clay hydrogel powder. After sieving, hydrogel microparticles with uniform particle size distribution were obtained.

[0069] (3) Polish the stainless steel plate with sandpaper, then clean it with acetone, ethanol and deionized water in sequence for 5 minutes, and dry it for later use.

[0070] (4) A bonding layer with a thickness of 0.1-0.3 mm (using Xin Gang DTM-SS17 varnish) is prepared on the surface of the stainless steel plate after step (3) by brushing. The varnish is pre-cured for 0.5 h.

[0071] (5) Spray the hydrogel microparticles obtained in step (2) onto the connecting layer prepared in step (4), and continue to cure at room temperature for 2 hours to prepare a coating with a wrinkled and undulating structure.

[0072] Antibacterial tests (E. coli) were conducted on the coating with the above-mentioned folded and undulating structure, and the results showed that it did not have a bacterial adhesion effect.

[0073] Comparative Example 3

[0074] (1) Isopropylacrylamide monomer (NIPAM), nanoclay (Clay S482), and ultrapure water were mixed and fully dissolved to form a homogeneous mixture. The amounts of NIPAM and S482 added were 10 wt% and 20 wt% of the mass of ultrapure water, respectively. Next, N,N,N',N'-tetramethylethylenediamine (0.3 wt%) as catalyst and potassium persulfide (0.3 wt%) as initiator were added to the mixture, and the mixture was stirred rapidly for approximately 30 seconds to obtain a prepolymer solution. The prepared prepolymer solution was immediately poured into a template for polymerization. After the reaction was complete, the mixture was peeled off from the template, and the residual solution was washed away with pure water to obtain the desired product. Figure 1 The PNIPAM / Clay composite hydrogel shown.

[0075] (2) The PNIPAM / Clay composite hydrogel obtained in step (1) was pre-frozen overnight at -80℃, then placed in a vacuum freeze dryer and dried at -40℃ for 48 hours. It was then pre-crushed using a pulverizer, followed by ball milling at a speed of 1600 r / min for 2 minutes to obtain PNIPAM / Clay hydrogel powder. After sieving, hydrogel microparticles with uniform particle size distribution were obtained.

[0076] (3) Polish the stainless steel plate with sandpaper, then clean it with acetone, ethanol and deionized water in sequence for 5 minutes, and dry it for later use.

[0077] (4) Using a brush coating method, a bonding layer with a thickness of 0.1-0.3 mm is prepared on the surface of the stainless steel plate after the treatment in step (3) (using Xin Gang DTM-SS17 varnish), and the varnish is pre-cured for 1.5 h.

[0078] (5) Spray the hydrogel microparticles obtained in step (2) onto the bonding layer prepared in step (4) and continue to cure at room temperature for 2 hours. However, because the curing time of the primer is long, the hydrogel microparticles cannot form effective hydrogen bonds with the primer and cannot form a coating.

[0079] The above description is merely a preferred embodiment of the present invention, and therefore should not be construed as limiting the scope of the present invention. All equivalent changes and modifications made in accordance with the scope of the patent and the contents of the specification should still fall within the scope of the present invention.

Claims

1. A method for the preparation of a marine antifouling anti-biofouling hydrogel microparticle coating, characterized by: Includes the following steps: (1) The hydrophilic polymer monomer, nano clay and ultrapure water are mixed and fully dissolved to form a uniform mixture. Then, the catalyst N,N,N',N'-tetramethylethylenediamine and the initiator potassium persulfate are added and stirred rapidly to obtain a prepolymer solution. The prepared prepolymer solution is immediately poured into the template for polymerization reaction. Then, it is peeled off from the template and the residual solution is washed away to obtain a composite hydrogel. (2) The composite hydrogel obtained in step (1) is pre-frozen, then vacuum freeze-dried, then pre-pulverized, and then ball-milled to obtain hydrogel powder; after sieving, hydrogel microparticles with uniform particle size distribution are obtained. (3) Polish the stainless steel plate with sandpaper, then clean it with acetone, ethanol and deionized water in sequence using ultrasonic cleaning, and dry it for later use. (4) Prepare a pre-cured bonding layer on the surface of the stainless steel plate after the treatment in step (3); (5) Spray the hydrogel microparticles obtained in step (2) onto the bonding layer prepared in step (4) and continue to cure at room temperature to prepare the marine antifouling and antibioadhesion hydrogel microparticle coating.

2. The production method according to claim 1, characterized by: The hydrophilic polymer monomers are selected from isopropylacrylamide, acrylamide, ethylene glycol, vinyl alcohol, and sodium alginate.

3. The preparation method according to claim 2, characterized in that: The hydrophilic polymer monomer is isopropylacrylamide or acrylamide.

4. The production method according to claim 1, wherein: The nano-clay is selected from S482, XLG, RD and nano-montmorillonite.

5. The production method according to claim 4, characterized by: The nano-clay is S482.

6. The production method according to claim 1, wherein: The bonding layer is made by brushing, rolling or spraying with Xingang DTM-SS17 varnish, Ergo7300 epoxy adhesive or Araldite 937308 epoxy adhesive, and its thickness is 0.1-0.3mm.

7. The production method according to claim 1, wherein: The hydrophilic polymer monomer is isopropylacrylamide or acrylamide, the nano-clay is S482, and the connecting layer is obtained by brushing on Xin Gang DTM-SS17 varnish, and the pre-curing time of Xin Gang DTM-SS17 varnish is 1 hour.

8. The production method according to any one of claims 1 to 7, characterized by: In step (1), the hydrophilic polymer monomer and the nano clay are 10 wt% and 20 wt% of the ultrapure water, respectively.

9. The production method according to claim 8, characterized by: In step (1), the amount of catalyst N,N,N',N'-tetramethylethylenediamine and initiator potassium persulfide added is 0.3 wt%.

10. The production method according to any one of claims 1 to 7, characterized by: In step (2), the pre-freezing temperature is -80℃, the vacuum freeze-drying condition is -40℃ for 48 hours, and the ball milling condition is ball milling at 1600r / min for 2 minutes; the continued curing time in step (4) is 2 hours.

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