Water-based photocureable coating and preparation method thereof

Abstract

The invention relates to a water-based photocureable coating and a preparation method thereof, and belongs to the technical crossing field of biomass materials and photocureable resins. The water-based photocureable coating is prepared from the following raw materials: 50 to 60 parts of acrylic acid modified keratin, 10 to 18 parts of acrylic acid monomer, 10 to 15 parts of organic aldehyde, 0.5 to 1.2 parts of initiator, 3 to 6 parts of emulsifier, 0.5 to 0.7 part of catalyst, 0.2 to 0.6 part of defoaming agent and 40 to 60 parts of deionized water. Pig hair is converted into bio-based macromolecules with sulfydryl, amino and acrylic active groups on the molecular chain surface, the bio-based macromolecules serve as a reaction raw material of acrylic resin and further generate macromolecules with an acrylic monomer, meanwhile, double bonds and aldehyde groups in organic aldehyde can react with sulfydryl and amino in keratin respectively, and therefore the keratin is prepared. Therefore, netted crosslinking is formed among keratin molecular chains, and the strength of the resin after film formation is enhanced. The pig hair is used as the raw material, the cost is low, no organic solvent exists, the film has the advantages of high strength and low VOC after being formed, and the coating is suitable for the field of environment-friendly coatings.

Description

Technical Field

[0001] The present invention belongs to the intersection field of biomass materials and light-curing resin technology, and in particular relates to a water-based light-curing coating and a preparation method thereof. Background Art

[0002] In the field of coatings, bio-based materials, particularly vegetable oils, have been widely used to prepare new green and environmentally friendly coatings. This is because vegetable oils are non-toxic, low-volatile, biodegradable, and readily available. Since the 19th century, a series of studies have been conducted on plant oil-based polymers. For example, triglycerides in vegetable oils are hydrolyzed with glycerol to produce monoglycerides for the preparation of alkyd resins; drying oils or fatty acids are first maleated and then transesterified with epoxy prepolymers to produce fatty acid-modified epoxy coatings; soybean oil is epoxidized and then combined with acrylates to prepare epoxidized soybean oil acrylate resins; monoglycerides are also polyols that can react with diisocyanates to produce polyurethanes. Vegetable oils used to prepare water-based polyurethanes include sunflower oil, castor oil, rapeseed oil, and soybean oil; and tung oil is directly formed into biodegradable coatings after thermal cross-linking polymerization. However, the demand for vegetable oil as a human diet is also increasing. Therefore, the production cost of using vegetable oil as a raw material for synthetic resin is relatively high. Therefore, it is urgent to explore a method to synthesize the resin needed by people using cheap and widely available biomaterials.

[0003] Pig hair, a byproduct of slaughterhouses, is often discarded as solid waste, resulting in a waste of resources and a significant environmental burden. However, the primary component of pig hair is keratin, which is synthesized through a condensation reaction of amino acids such as glutamic acid, cystine, and arginine. These amino acids are rich in disulfide bonds and amino groups. Decomposition and activation of pig hair can expose these groups, allowing them to serve as active sites for chemical reactions. However, no studies have yet been conducted on this topic. Summary of the Invention

[0004] In view of the above-mentioned deficiencies in the prior art, the present invention aims to provide a water-based photocurable coating and a preparation method thereof. Pig hair, a by-product of slaughterhouses, is used as raw material. Through the steps of impurity removal, hair decomposition, and acrylic acid modification, the hair is converted into a bio-based polymer with thiol, amino, and acrylic acid active groups on the molecular chain surface. The bio-based polymer serves as the reaction raw material for acrylic resin, and reacts with acrylic acid monomers to further generate a polymer. Simultaneously, the double bonds and aldehyde groups in the organic aldehyde can react with the thiol and amino groups in keratin, respectively, to form chemical bonds between the keratin molecular chains, forming a network crosslinking, thereby enhancing the strength of the resin after film formation.

[0005] The specific technical solutions are as follows:

[0006] A water-based light-curing coating comprises the following raw materials, calculated by weight: 50-60 parts of acrylic acid-modified keratin, 10-18 parts of acrylic acid monomer, 10-15 parts of organic aldehyde, 0.5-1.2 parts of initiator, 3-6 parts of emulsifier, 0.5-0.7 parts of catalyst, 0.2-0.6 parts of defoamer, and 40-60 parts of deionized water. The preparation method of the acrylic acid-modified keratin comprises the following steps:

[0007] S1 impurity removal: The collected pig hair is rinsed with water to remove pig feces, internal organs, and impurities on the skin, and then the pig hair is immersed in a 1:1 acetone / methanol mixed solution, stirred at a speed of 200 to 500 rpm, and mixed for 12 to 24 hours, and then the pig hair is rinsed with water, dried in an oven at 80 to 100° C. for 12 to 18 hours, and finally the dried pig hair is crushed into fine particles using a grinder to obtain fine particles of pig hair;

[0008] S2 Pig hair decomposition: 8 mol of urea, 0.2 mol of sodium metabisulfite and 1 mol of sodium hydroxide are dissolved in 200 mL of distilled water, and the resulting fine-grained pig hair is then treated in a mixed solution of urea / sodium metabisulfite / sodium hydroxide at a stirring speed of 500-800 rpm and a temperature of 80-100° C. for 12-24 hours to promote the decomposition of the pig hair. After the reaction is completed, the mixture is filtered with a 120-mesh stainless steel sieve, the filtrate is taken, and centrifuged to remove the pig hair residue. The centrifuged filtrate is then dialyzed to remove urea, sodium metabisulfite and sodium hydroxide to obtain a purified pig hair extract; the mass ratio of the fine-grained pig hair to the mixed solution of urea / sodium metabisulfite / sodium hydroxide is 1:10-18;

[0009] S3 Acrylic acid modification: The obtained pig hair extract is added to a multifunctional reactor, and then the pH value of the pig hair extract is adjusted to 12-14, and then 3-formyl-2-butenoic acid methyl ester is added, and nitrogen is introduced for 5-10 minutes, and then the temperature is raised to 80-90°C, and the reaction is carried out at a constant temperature for 2-4 hours at a stirring speed of 500-1000 rpm. After the reaction is completed, the temperature is lowered to 30°C, and then the pH of the mixed solution is adjusted to 3, and the stirring reaction is continued for 8-12 hours. The reaction is stopped and allowed to stand for 0.5-1 hour, the liquid is separated, the supernatant is removed, and then the salts are removed by dialyzing to obtain an acrylic acid-modified keratin solution.

[0010] In some embodiments, the acrylic monomer is a combination of one or more of ethyl acrylate, butyl acrylate, methacrylic acid, methyl methacrylate, and isobutyl acrylate.

[0011] In some embodiments, the organic aldehyde is a combination of one or more of acrolein, crotonaldehyde, 2-methyl-2-pentenal, malondialdehyde, and succinaldehyde.

[0012] In some embodiments, the initiator is a combination of one or more of benzophenone, 2,4-dihydroxybenzophenone, and 2,2-dimethoxy-2-phenylacetophenone.

[0013] In some embodiments, the emulsifier is one or more of 2-acrylamido-methyl-propyl sodium sulfate and 2-acrylamido-methyl-propyl ammonium sulfate.

[0014] In some embodiments, the defoaming agent is a combination of one or more of polysiloxane, GP-type glycerol polyether, and ethylene glycol siloxane.

[0015] In some embodiments, the catalyst is a combination of one or more of antimony trioxide and Sn(Oct)2.

[0016] The present invention also provides a method for preparing the above-mentioned water-based light-curing coating, characterized in that the preparation method comprises the following steps:

[0017] S4: adding acrylic acid-modified keratin, acrylic acid monomer, initiator, emulsifier, defoamer and deionized water into a multifunctional reactor, introducing nitrogen for 20 minutes to remove air from the reactor, and stirring at a stirring speed of 800 to 1000 rpm and a temperature of 40 to 60° C. for 30 to 60 minutes to form a uniform emulsion;

[0018] S5 adds organic aldehyde and catalyst, raises the temperature to 50-60°C, stirs for 30-60 minutes, then raises the temperature to 108-120°C, and reacts at constant temperature for 2-4 hours;

[0019] After the reaction is completed, S6 cools the mixture to 50°C, adjusts the viscosity of the mixed solution to 9000-12000 cps / 25°C, and disperses the mixture at a high speed for 1-3 hours at a stirring speed of 8000-10000 rpm to form a stable emulsion, thereby obtaining the water-based photocurable coating.

[0020] The present invention has the following advantages:

[0021] (1) Using pig hair as raw material has low production cost and can reduce the burden on the environment caused by direct disposal of pig hair;

[0022] (2) The formula does not involve the use of organic solvents, and the subsequent use of water-based light-curing coatings will not produce gases harmful to human health, which is in line with the green and environmentally friendly production concept;

[0023] (3) The present invention converts pig hair into a bio-based polymer with thiol, amino and acrylic acid active groups on the molecular chain surface through the steps of impurity removal, pig hair decomposition and acrylic acid modification. The bio-based polymer is used as a reaction raw material for acrylic resin and reacts with acrylic acid monomer to further generate a polymer. At the same time, the double bonds and aldehyde groups in the organic aldehyde can react with the thiol and amino groups in keratin respectively, so that chemical bonds are formed between the keratin molecular chains, forming a network cross-linking, thereby enhancing the strength of the resin after film formation. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 Schematic diagram of the chemical reaction molecules in the preparation process of water-based light-curing coatings;

[0025] Figure 2 Infrared spectrum of fine-grained pig hair prepared in Example 1;

[0026] Figure 3 Infrared spectra of the acrylic acid-modified keratin prepared in Examples 6 to 8;

[0027] Figure 4 Optical photographs of the water-based photocurable coatings prepared in Examples 9 to 11 after film formation;

[0028] Figure 5 Scanning electron microscope images of the water-based light-curing coatings prepared in Examples 9 to 11 after film formation;

[0029] Figure 6 Tensile curves of the water-based photocurable coatings prepared in Examples 9 to 14 after film formation. DETAILED DESCRIPTION

[0030] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the drawings, technical process steps, specific implementation conditions and materials in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0031] Example 1

[0032] The collected pig hair was rinsed with water to remove pig feces, internal organs, and impurities on the surface of the pig hair. The pig hair was then immersed in a 1:1 acetone / methanol mixed solution and mixed for 24 hours at a stirring speed of 200 rpm. The pig hair was then rinsed with water and dried in an 80°C oven for 18 hours. Finally, the dried pig hair was crushed into fine particles using a grinder to obtain fine particles of pig hair. The infrared spectrum test was performed, as shown in FIG. Figure 2 shown.

[0033] Example 2

[0034] 8 mol of urea, 0.2 mol of sodium metabisulfite and 1 mol of sodium hydroxide were dissolved in 200 mL of distilled water. The fine-particle pig hair prepared in Example 1 was then treated in a mixed solution of urea / sodium metabisulfite / sodium hydroxide at a stirring speed of 500 rpm and a temperature of 100° C. for 12 hours to promote the decomposition of the pig hair. The mass ratio of the fine-particle pig hair to the mixed solution of urea / sodium metabisulfite / sodium hydroxide was 1:10. After the reaction was completed, the mixture was filtered through a 120-mesh stainless steel sieve, the filtrate was taken, and the pig hair residue was removed by centrifugation. The centrifuged filtrate was then dialyzed to remove urea, sodium metabisulfite and sodium hydroxide to obtain a purified pig hair extract.

[0035] Example 3

[0036] 8 mol of urea, 0.2 mol of sodium metabisulfite and 1 mol of sodium hydroxide were dissolved in 200 mL of distilled water. The fine-particle pig hair prepared in Example 1 was then treated in a mixed solution of urea / sodium metabisulfite / sodium hydroxide at a stirring speed of 600 rpm and a temperature of 90° C. for 18 hours to promote the decomposition of the pig hair. The mass ratio of the fine-particle pig hair to the mixed solution of urea / sodium metabisulfite / sodium hydroxide was 1:14. After the reaction was completed, the mixture was filtered through a 120-mesh stainless steel sieve, the filtrate was taken, and the pig hair residue was removed by centrifugation. The centrifuged filtrate was then dialyzed to remove urea, sodium metabisulfite and sodium hydroxide to obtain a purified pig hair extract.

[0037] Example 4

[0038] 8 mol of urea, 0.2 mol of sodium metabisulfite and 1 mol of sodium hydroxide were dissolved in 200 mL of distilled water. The fine-particle pig hair prepared in Example 1 was then treated in a mixed solution of urea / sodium metabisulfite / sodium hydroxide at a stirring speed of 800 rpm and a temperature of 100° C. for 12 hours to promote the decomposition of the pig hair. The mass ratio of the fine-particle pig hair to the mixed solution of urea / sodium metabisulfite / sodium hydroxide was 1:18. After the reaction was completed, the mixture was filtered through a 120-mesh stainless steel sieve, the filtrate was taken, and the pig hair residue was removed by centrifugation. The centrifuged filtrate was then dialyzed to remove urea, sodium metabisulfite and sodium hydroxide to obtain a purified pig hair extract.

[0039] Example 5

[0040] The pig hair extracts prepared in Examples 2 to 4 were tested for amino content. 1 mL of the solutions prepared in Examples 2 to 4 were added to a ninhydrin solution for color reaction. The absorbance of the resulting solutions was then measured spectrophotometrically. According to the Lambert-Beer law and the standard sample, the amino content of the solutions prepared in Examples 2 to 4 was 0.85 mmol g -1 、0.93mmol g-1 and 0.91 mmol g -1 .

[0041] Example 6

[0042] The pig hair extract obtained in Example 2 was added to a multifunctional reactor, and the pH value of the pig hair extract was adjusted to 12. 3-formyl-2-butenoic acid methyl ester was then added, and nitrogen was introduced for 5 to 10 minutes. The temperature was then raised to 80° C. and the reaction was carried out at a constant temperature of 500 rpm for 4 hours. After the reaction was completed, the temperature was lowered to 30° C., and the pH of the mixed solution was adjusted to 3. The reaction was continued with stirring for 8 hours. The reaction was stopped and allowed to stand for 1 hour. The liquid was separated, the supernatant was removed, and then dialyzed to remove salts to obtain an acrylic acid-modified keratin solution. The obtained acrylic acid-modified keratin solution was subjected to infrared spectroscopy test. The results were as follows: Figure 3 As shown, compared Figure 2 The infrared spectrum of this embodiment shows characteristic peaks of C=C, C=O and CO, indicating that the acrylic acid modification is successful.

[0043] Example 7

[0044] The pig hair extract obtained in Example 3 was added to a multifunctional reactor, and the pH value of the pig hair extract was adjusted to 13. 3-formyl-2-butenoic acid methyl ester was then added, and nitrogen was introduced for 5 to 10 minutes. The temperature was then raised to 85° C. and the reaction was carried out at a constant temperature of 700 rpm for 3 hours. After the reaction was completed, the temperature was lowered to 30° C., and the pH of the mixed solution was adjusted to 3. The stirring reaction was continued for 10 hours. The reaction was stopped and allowed to stand for 1 hour. The liquid was separated, the supernatant was removed, and then dialyzed to remove salts to obtain an acrylic acid-modified keratin solution. The obtained acrylic acid-modified keratin solution was subjected to infrared spectroscopy test. The results were as follows: Figure 3 As shown, compared Figure 2 The infrared spectrum of this embodiment shows characteristic peaks of C=C, C=O and CO, indicating that the acrylic acid modification is successful.

[0045] Example 8

[0046] The pig hair extract obtained in Example 4 was added to a multifunctional reactor, and the pH value of the pig hair extract was adjusted to 14. 3-formyl-2-butenoic acid methyl ester was then added, and nitrogen was introduced for 5 to 10 minutes. The temperature was then raised to 90° C. and the reaction was carried out at a constant temperature of 1000 rpm for 2 hours. After the reaction was completed, the temperature was lowered to 30° C., and the pH of the mixed solution was adjusted to 3. The reaction was continued with stirring for 12 hours. The reaction was stopped and allowed to stand for 1 hour. The liquid was separated, the supernatant was removed, and then dialyzed to remove salts to obtain an acrylic acid-modified keratin solution. The obtained acrylic acid-modified keratin solution was subjected to infrared spectroscopy test. The results were as follows: Figure 3 As shown, compared Figure 2The infrared spectrum of this embodiment shows characteristic peaks of C=C, C=O and CO, indicating that the acrylic acid modification is successful.

[0047] Example 9

[0048] Table 1 Raw material ratio of water-based light-curing coating in Example 9

[0049]

[0050]

[0051] The acrylic acid-modified keratin used in this example was prepared in Example 6.

[0052] Acrylic acid modified keratin, ethyl acrylate, benzophenone, 2-acrylamido-methyl-propyl sodium sulfate, polysiloxane and deionized water are added to a multifunctional reactor, nitrogen is introduced for 20 minutes to remove the air in the reactor, and the mixture is stirred at a stirring speed of 800 rpm and a temperature of 40°C for 60 minutes to form a uniform emulsion; acrolein is added, antimony trioxide is added, the temperature is raised to 50°C, stirred for 60 minutes, and then the temperature is raised to 108°C and the reaction is carried out at a constant temperature for 4 hours; after the reaction is completed, the temperature is lowered to 50°C, the viscosity of the mixed solution is adjusted to 9000cps / 25°C, and the mixture is dispersed at a high speed for 3 hours at a stirring speed of 8000 rpm to form a stable emulsion, thereby obtaining the water-based light-curing coating. The prepared water-based light-curing coating is subjected to ultraviolet light curing (curing for 3 hours under ultraviolet light 365nm irradiation), and the resulting film is as shown in FIG. Figure 4 As shown in a, it is translucent. Scanning electron microscopy analysis, such as Figure 5 As shown, a dense structure is formed on the surface, which is beneficial to improving the membrane strength.

[0053] According to GB / T 6739-1996 "Coating Hardness Pencil Test Method", the prepared water-based light-curing coating was cured into a film by manual method (cured for 3 hours under ultraviolet light 365nm) and the strength test was performed. The test results showed that the film strength was >B.

[0054] The VOC of the prepared water-based photocurable coating film was tested according to GB / T 23985-2009 "Paints and varnishes - Determination of volatile organic compound (VOC) content - Difference method", and the result was VOC≤62g / L.

[0055] The water resistance of the prepared water-based photocurable coating film was tested according to GB / T 1727-1992. After immersion for 48 hours, the water absorption rate was 11.8%.

[0056] Example 10

[0057] Table 2 Raw material ratio of water-based light-curing coating in Example 10

[0058] Acrylic acid modified keratin 55 servings Butyl acrylate 14 servings Malondialdehyde 12 servings 2,4-Dihydroxybenzophenone 0.8 servings 2-Acrylamido-methyl-propylammonium sulfate 5 servings GP type glycerol polyether 0.4 serving <![CDATA[Sn(Oct)2]]> 0.6 servings Deionized water 50 servings

[0059] The acrylic acid-modified keratin used in this example was prepared in Example 7.

[0060] like Figure 1 As shown, acrylic acid-modified keratin, butyl acrylate, 2,4-dihydroxybenzophenone, 2-acrylamido-methyl-propyl ammonium sulfate, GP-type glycerol polyether and deionized water are added to a multifunctional reactor, nitrogen is introduced for 20 minutes, the air in the reactor is removed, and the mixture is stirred at a stirring speed of 900 rpm and a temperature of 50°C for 45 minutes to form a uniform emulsion; malondialdehyde is added, Sn(Oct)2 is added, the temperature is raised to 55°C, stirred for 45 minutes, and then the temperature is raised to 114°C and the reaction is carried out at a constant temperature for 3 hours; after the reaction is completed, the temperature is lowered to 50°C, the viscosity of the mixed solution is adjusted to 10000cps / 25°C, and the mixture is dispersed at a high speed for 2 hours at a stirring speed of 9000 rpm to form a stable emulsion, thereby obtaining the water-based light-curing coating. The prepared water-based light-curing coating is subjected to UV curing (cured for 3 hours under UV light 365nm), and the resulting film is as shown Figure 4 As shown in b, it is translucent. Scanning electron microscopy analysis, such as Figure 5 As shown, a dense structure is formed on the surface, which is beneficial to improving the membrane strength.

[0061] According to GB / T 6739-1996 "Coating Hardness Pencil Test Method", the prepared water-based light-curing coating was cured into a film by manual method (cured for 3 hours under ultraviolet light 365nm) and the strength test was performed. The test results showed that the film strength was >B.

[0062] The VOC of the prepared water-based photocurable coating film was tested according to GB / T 23985-2009 "Paints and varnishes - Determination of volatile organic compound (VOC) content - Difference method", and the result was VOC≤62g / L.

[0063] The water resistance of the prepared water-based photocurable coating film was tested according to GB / T 1727-1992. After immersion for 48 hours, the water absorption rate was 11.8%.

[0064] Example 11

[0065] like Figure 1As shown, acrylic acid-modified keratin, methacrylic acid, benzophenone, 2-acrylamido-methyl-propyl ammonium sulfate, ethylene glycol siloxane and deionized water are added to a multifunctional reactor, nitrogen is introduced for 20 minutes to remove the air in the reactor, and the mixture is stirred at a stirring speed of 1000 rpm and a temperature of 60°C for 30 minutes to form a uniform emulsion; crotonaldehyde is added, Sn(Oct)2 is added, the mixture is heated to 60°C and stirred for 30 minutes, and then heated to 120°C and reacted at a constant temperature for 2 hours; after the reaction is completed, the mixture is cooled to 50°C, the viscosity of the mixed solution is adjusted to 12000cps / 25°C, and the mixture is dispersed at a high speed for 1 hour at a stirring speed of 10000 rpm to form a stable emulsion, thereby obtaining the water-based light-curing coating. The prepared water-based light-curing coating is subjected to UV curing (cured for 3 hours under UV light 365nm), and the resulting film is as shown. Figure 4 As shown in c, it is translucent. Scanning electron microscopy analysis, such as Figure 5 As shown, a dense structure is formed on the surface, which is beneficial to improving the membrane strength.

[0066] Table 3 Raw material ratio of water-based light-curing coating in Example 11

[0067] Acrylic acid modified keratin 60 servings Methacrylic acid 18 servings Crotonaldehyde 15 servings Benzophenone 1.2 servings 2-Acrylamido-methyl-propylammonium sulfate 6 servings Ethylene glycol siloxane 0.6 servings <![CDATA[Sn(Oct)2]]> 0.7 serving Deionized water 60 servings

[0068] The acrylic acid-modified keratin used in this example was prepared in Example 8.

[0069] According to GB / T 6739-1996 "Coating Hardness Pencil Test Method", the prepared water-based light-curing coating was cured into a film by manual method (cured for 3 hours under ultraviolet light 365nm) and the strength test was performed. The test results showed that the film strength was >B.

[0070] The VOC of the prepared water-based photocurable coating film was tested according to GB / T 23985-2009 "Paints and varnishes - Determination of volatile organic compound (VOC) content - Difference method", and the result was VOC≤62g / L.

[0071] The water resistance of the prepared water-based photocurable coating film was tested according to GB / T 1727-1992. After immersion for 48 hours, the water absorption rate was 11.8%.

[0072] Comparative Example 1

[0073] The process parameters were the same as those in Example 9, and the formula remained the same except that acrolein in Example 9 was not added.

[0074] Comparative Example 2

[0075] The process parameters were consistent with those in Example 10, and the formula remained the same except that the malondialdehyde in Example 10 was not added.

[0076] Comparative Example 3

[0077] The process parameters were consistent with those in Example 11, and the formula remained the same except that crotonaldehyde in Example 11 was not added.

[0078] Strength test:

[0079] The tensile strength of the films of the water-based photocurable coatings prepared in Examples 9 to 14 after film formation (cured for 3 hours under ultraviolet light 365 nm) was tested using a universal tensile testing machine. The test results are as follows: Figure 6 As shown, the tensile strengths of the water-based photocurable coatings prepared in Examples 9 to 14 were 235.6 kPa, 278.9 kPa, 252.9 kPa, 118.7 kPa, 132.7 kPa, and 109.8 kPa, respectively, and the maximum deformations were 24.6%, 33.1%, 31.5%, 10.4%, 17.8%, and 11.6%, respectively.

[0080] By comparing Example 9 with Example 12, Example 10 with Example 13, and Example 11 with Example 14, the addition of polyaldehyde can promote the formation of network crosslinking of the resin after film formation, thereby improving the strength and toughness of the film; compared with the film strength of the water-based photocurable coatings prepared in Examples 9, 10 and 11 after film formation, the preparation process of Example 10 is the best, which provides guidance for subsequent actual production.

[0081] Technical personnel should note: Although the present invention has been described according to the above specific implementation methods, the inventive concept of the present invention is not limited to this invention. Any modification using the inventive concept will be included in the scope of protection of this patent.

Claims

1. A water-based light-curing coating, characterized in that: The water-based light-curing coating is composed of the following raw materials, in parts by weight: 50-60 parts of acrylic acid-modified keratin, 10-18 parts of acrylic acid monomer, 10-15 parts of organic aldehyde, 0.5-1.2 parts of initiator, 3-6 parts of emulsifier, 0.5-0.7 parts of catalyst, 0.2-0.6 parts of defoaming agent and 40-60 parts of deionized water. The preparation method of the acrylic acid-modified keratin comprises the following steps: S1 impurity removal: The collected pig hair is rinsed with water to remove pig feces, internal organs, and impurities on the skin, and then the pig hair is immersed in an acetone / methanol mixed solution with a mass ratio of 1:1, and mixed at a stirring speed of 200 to 500 rpm for 12 to 24 hours. The pig hair is then rinsed with water and dried in an oven at 80 to 100° C. for 12 to 18 hours. Finally, the dried pig hair is crushed into fine particles using a grinder to obtain fine particles of pig hair; S2 Pig hair decomposition: 8 mol of urea, 0.2 mol of sodium metabisulfite and 1 mol of sodium hydroxide are dissolved in 200 mL of distilled water, and the resulting fine-grained pig hair is then treated in a mixed solution of urea / sodium metabisulfite / sodium hydroxide at a stirring speed of 500-800 rpm and a temperature of 80-100° C. for 12-24 hours to promote the decomposition of the pig hair. After the reaction is completed, the mixture is filtered with a 120-mesh stainless steel sieve, the filtrate is taken, and centrifuged to remove the pig hair residue. The centrifuged filtrate is then dialyzed to remove urea, sodium metabisulfite and sodium hydroxide to obtain a purified pig hair extract; the mass ratio of the fine-grained pig hair to the mixed solution of urea / sodium metabisulfite / sodium hydroxide is 1:10-18; S3 Acrylic acid modification: The obtained pig hair extract is added to a multifunctional reactor, and then the pH value of the pig hair extract is adjusted to 12-14, and then 3-formyl-2-butenoic acid methyl ester is added, and nitrogen is introduced for 5-10 minutes, and then the temperature is raised to 80-90°C, and the reaction is carried out at a constant temperature for 2-4 hours at a stirring speed of 500-1000 rpm. After the reaction is completed, the temperature is lowered to 30°C, and then the pH of the mixed solution is adjusted to 3, and the stirring reaction is continued for 8-12 hours. The reaction is stopped and allowed to stand for 0.5-1 hour, the liquid is separated, the supernatant is removed, and then the salts are removed by dialyzing to obtain an acrylic acid-modified keratin solution.

2. A water-based light-curing coating according to claim 1, characterized in that: The acrylic monomer is a combination of one or more of ethyl acrylate, butyl acrylate, methacrylic acid, methyl methacrylate, and isobutyl acrylate.

3. The water-based light-curing coating according to claim 1, characterized in that: The organic aldehyde is a combination of one or more of acrolein, crotonaldehyde, 2-methyl-2-pentenal, malondialdehyde, and succinaldehyde.

4. The water-based light-curing coating according to claim 1, characterized in that: The initiator is a combination of one or more of benzophenone, 2,4-dihydroxybenzophenone, and 2,2-dimethoxy-2-phenylacetophenone.

5. The water-based light-curing coating according to claim 1, characterized in that: The emulsifier is one or more of 2-acrylamido-methyl-propyl sodium sulfate and 2-acrylamido-methyl-propyl ammonium sulfate.

6. The water-based light-curing coating according to claim 1, characterized in that: The defoaming agent is a combination of one or more of polysiloxane, GP type glycerol polyether and ethylene glycol siloxane.

7. The water-based light-curing coating according to claim 1, characterized in that: The catalyst may be a combination of one or more of antimony trioxide and Sn(Oct)2.

8. A method for preparing a water-based light-curing coating according to any one of claims 1 to 7, characterized in that: The preparation method comprises the following steps: S4: adding acrylic acid-modified keratin, acrylic acid monomer, initiator, emulsifier, defoamer and deionized water into a multifunctional reactor, introducing nitrogen for 20 minutes to remove air from the reactor, and stirring at a stirring speed of 800 to 1000 rpm and a temperature of 40 to 60° C. for 30 to 60 minutes to form a uniform emulsion; S5 adds organic aldehyde and catalyst, raises the temperature to 50-60°C, stirs for 30-60 minutes, then raises the temperature to 108-120°C, and reacts at constant temperature for 2-4 hours; After the reaction is completed, S6 cools the mixture to 50°C, adjusts the viscosity of the mixed reaction system to 9000-12000 cps / 25°C, and disperses the mixture at a high speed for 1-3 hours at a stirring speed of 8000-10000 rpm to form a stable emulsion, thereby obtaining the water-based photocurable coating.

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