A bio-based modified polyurethane resin coating

Abstract

The application discloses a kind of bio-based modified polyurethane resin coatings, and the preparation raw materials of bio-based modified polyurethane resin coating are calculated as weight fraction polyester polyol 30-40 parts, acrylate 20-30 parts, trimethylolpropane 5-10 parts, microcrystalline cellulose 1-5 parts, 4,4'-diphenyldimethyl dicarboxylate 3-6 parts, omega-undecyl amino acid 4-8 parts, high molecular polymer of isosorbide 4-8 parts, chain extender 1-4 parts, coupling agent 1-3 parts, curing agent 0.1-2 parts.The bio-based modified polyurethane resin coating of the application has excellent hardness and flexibility, strong adhesion after film formation, and the low temperature resistance degree can reach-40 DEG C.In addition, the polyurethane coating also has good flame retardance, fast curing speed, and can be continuously sprayed on any curved surface, vertical surface and top surface without sagging phenomenon.

Description

Technical Field

[0001] This invention belongs to the field of coating technology, specifically relating to a polyurethane resin coating, and more particularly to a bio-based modified polyurethane resin coating. Background Technology

[0002] Polyurethane coatings are a common type of coating, and can be divided into two-component and one-component polyurethane coatings. Two-component polyurethane coatings generally consist of two parts: an isocyanate prepolymer (also called a low-molecular-weight urethane polymer) and a hydroxyl-containing resin, usually referred to as the curing agent and the main component. Their main applications include wood coatings, automotive repair coatings, anti-corrosion coatings, floor paints, electronic coatings, specialty coatings, and polyurethane waterproof coatings. One-component polyurethane coatings mainly include urethane oil coatings, moisture-curing polyurethane coatings, and closed-type polyurethane coatings, primarily used for floor coatings, anti-corrosion coatings, and pre-rolled membrane coatings. Their overall performance is not as comprehensive as that of two-component coatings.

[0003] CN116904102A discloses a single-component polyurethane waterproof coating and its preparation method. The single-component polyurethane waterproof coating includes the following raw materials: a furan-like polyether polyol, a polydimethylphenol diol, a phenylsilane coupling agent, a composite latent curing agent, a plasticizer, a filler, toluene diisocyanate, a catalyst, a chain extender, and a viscosity reducer. This invention introduces furan-like rigid groups into the polyether backbone and introduces polydimethylphenol diol into the formulation system, increasing the content of hard segments in the polyurethane chain. It has good compatibility with the furan-like polyether polyol, synergistically improving the mechanical strength of the material without affecting the elongation of the polyurethane material. It also plays a synergistic reinforcing role with the phenylsilane coupling agent and the composite latent curing agent, significantly improving the mechanical properties of the polyurethane waterproof coating. This method has low manufacturing cost and is easy to industrialize.

[0004] CN116970333A discloses a two-component solvent-free polyurethane hand-applied coating composition, coating, and preparation method thereof. The coating composition consists of a branched polyester polyol and trimethylolpropane triglycidyl ether. The branched polyester polyol comprises 10-50 parts by weight, and the trimethylolpropane triglycidyl ether comprises 50-90 parts by weight, with the sum of the weight parts of the branched polyester polyol and trimethylolpropane triglycidyl ether equal to 100 parts. In this invention, the coating composition in the main formulation uses trimethylolpropane triglycidyl ether containing epoxy groups to replace part of the branched polyester polyol, reducing the amount of branched polyester polyol added. During the reaction with isocyanate, the epoxy groups first undergo a ring-opening reaction, and the hydroxyl groups formed after ring-opening then react with isocyanate. This two-step reaction curing effectively prolongs the reaction time, thereby extending the gel time and enabling hand-applied coating.

[0005] However, neither single-component nor two-component polyurethane coatings can simultaneously meet the dual requirements of hardness and flexibility. Therefore, there is an urgent need to provide a polyurethane coating that combines both flexibility and hardness with better overall performance to meet application needs. Summary of the Invention

[0006] In view of the shortcomings of the prior art, the purpose of this invention is to provide a bio-based modified polyurethane resin coating, which mainly solves the problems of flexibility, hardness and flame retardancy of polyurethane coatings, so that the polyurethane resin coating has the characteristics of wear resistance, strong adhesion, high flexibility and flame retardancy.

[0007] To achieve this objective, the present invention adopts the following technical solution:

[0008] In a first aspect, the present invention provides a bio-based modified polyurethane resin coating, wherein the raw materials for preparing the bio-based modified polyurethane resin coating include, by weight, 30-40 parts of polyester polyol, 20-30 parts of acrylate, 5-10 parts of trimethylolpropane, 1-5 parts of microcrystalline cellulose, 3-6 parts of dimethyl 4,4'-biphenyl dicarboxylate, 4-8 parts of ω-undecyl amino acid, 4-8 parts of isosorbide polymer, 1-4 parts of chain extender, 1-3 parts of coupling agent, and 0.1-2 parts of curing agent.

[0009] In the polyurethane coating of this invention, the dimethyl 4,4'-biphenyl dicarboxylate is a recycled biomass resource, which can be used to improve the toughness of the polyurethane coating and has a very good promoting effect on the tensile strength and elongation at break of the polyurethane; the polar groups of the ω-undecyl amino acid enter the polyurethane, which can reduce the surface tension of the film-forming material and the coating, and improve the adhesion of the coating; the microcrystalline cellulose plays a cross-linking and reinforcing role, and the microcrystalline cellulose and chain extender synergistically can improve the tensile strength of the coating; the trimethylolpropane can improve the tensile strength and flexibility of the coating, etc., and can make the polyurethane coating have higher stability. Through the synergistic combination of the above four components, the polyurethane coating of this invention can form a high-strength cross-linked network structure, which not only improves the toughness of the polyurethane coating, but also promotes the hardness of the polyurethane coating after curing and film formation, while enhancing wear resistance, and improving flexibility and anti-aging properties.

[0010] The amount of polyester polyol added in the bio-based modified polyurethane resin coating of the present invention can be 30 parts, 31 parts, 32 parts, 33 parts, 34 parts, 35 parts, 36 parts, 37 parts, 38 parts, 39 parts, or 40 parts, etc.

[0011] The amount of acrylate added can be 20 parts, 21 parts, 22 parts, 23 parts, 24 parts, 25 parts, 26 parts, 27 parts, 28 parts, 29 parts, or 30 parts, etc.

[0012] The amount of trimethylolpropane added can be 5 parts, 5.5 parts, 6 parts, 6.5 parts, 7 parts, 7.5 parts, 8 parts, 8.5 parts, 9 parts, 9.5 parts, or 10 parts, etc.

[0013] The amount of microcrystalline cellulose added can be 1 part, 1.5 parts, 2 parts, 2.5 parts, 3 parts, 3.5 parts, 4 parts, 4.5 parts, or 5 parts, etc.

[0014] The amount of dimethyl 4,4'-biphenyl dicarboxylate added can be 3 parts, 3.5 parts, 4 parts, 4.5 parts, 5 parts, 5.5 parts, or 6 parts, etc.

[0015] The amount of ω-undecainine added can be 4-8 parts, 4.5 parts, 5 parts, 5.5 parts, 6 parts, 6.5 parts, 7 parts, 7.5 parts, or 8 parts, etc.;

[0016] The amount of the isosorbide polymer added can be 4 parts, 4.5 parts, 5 parts, 5.5 parts, 6 parts, 6.5 parts, 7 parts, 7.5 parts, or 8 parts, etc.;

[0017] The amount of chain extender added can be 1 part, 1.2 parts, 1.5 parts, 1.8 parts, 2 parts, 2.2 parts, 2.5 parts, 2.8 parts, 3 parts, 3.2 parts, 3.5 parts, 3.8 parts, or 4 parts, etc.;

[0018] The amount of the coupling agent added can be 1 part, 1.2 parts, 1.5 parts, 1.8 parts, 2 parts, 2.2 parts, 2.5 parts, 2.8 parts, or 3 parts, etc.;

[0019] The amount of curing agent added can be 0.1 parts, 0.2 parts, 0.4 parts, 0.5 parts, 0.6 parts, 0.8 parts, 1 part, 1.2 parts, 1.4 parts, 1.5 parts, 1.6 parts, 1.8 parts, or 2 parts, etc.

[0020] Preferably, the raw materials for preparing the bio-based modified polyurethane resin coating include, by weight, 32-38 parts of polyester polyol, 23-28 parts of acrylate, 6-9 parts of trimethylolpropane, 2-4 parts of microcrystalline cellulose, 3-5 parts of dimethyl 4,4'-biphenyl dicarboxylate, 5-7 parts of ω-undecyl amino acid, 5-7 parts of isosorbide polymer, 2-3 parts of chain extender, 1-2 parts of coupling agent, and 0.5-1.5 parts of curing agent.

[0021] Preferably, the ω-undecaine is generated by the cleavage of castor oil.

[0022] Preferably, the preparation of the ω-undecaine includes the following steps:

[0023] (1) Castor oil is alcoholyzed with methanol to produce methyl ricinoleate;

[0024] (2) Methyl ricinoleate was decomposed into heptanal and undecenoic acid methyl ester at high temperature;

[0025] (3) Hydrolyze undecenoic acid methyl ester to generate undecenoic acid;

[0026] (4) Undecenoic acid reacts with hydrogen bromide under the action of peroxide to generate undecanoic acid;

[0027] (5) ω-undecanoic acid was prepared by reacting bromoundecanoic acid with ammonia.

[0028] Preferably, the mass ratio of castor oil to methanol is 1:(1-2), for example, it can be 1:1, 1:1.1, 1:1.2, 1:1.3, 1:1.4, 1:1.5, 1:1.6, 1:1.7, 1:1.8, 1:1.9 or 1:2, etc.

[0029] Preferably, the mass ratio of undecenoic acid to hydrogen bromide is 1:(1-3), for example, it can be 1:1, 1:1.1, 1:1.3, 1:1.5, 1:1.7, 1:1.9, 1:2, 1:2.1, 1:2.3, 1:2.5, 1:2.7, 1:2.9 or 1:3, etc.

[0030] Preferably, the mass ratio of undecanoic acid to ammonia is 1:(1-5), for example, it can be 1:1, 1:1.1, 1:1.5, 1:2, 1:2.2, 1:2.5, 1:3, 1:3.2, 1:3.5, 1:4, 1:4.2, 1:4.5, 1:4.8 or 1:5, etc.

[0031] Preferably, the peroxide includes any one or a combination of at least two of di-tert-butyl peroxide, di-tert-pentyl peroxide, benzoyl peroxide, or benzoyl tert-butyl peroxide.

[0032] Preferably, the mass ratio of undecenoic acid to benzoyl tert-butyl peroxide is (10-100):1, for example, it can be 10:1, 20:1, 30:1, 40:1, 50:1, 60:1, 70:1, 80:1, 90:1 or 100:1, etc.

[0033] Preferably, the high temperature in step (2) is 450-550℃, for example, it can be 450℃, 460℃, 480℃, 500℃, 520℃, 540℃ or 550℃, etc.

[0034] Preferably, the polymeric chemical formula of isosorbide is:

[0035]

[0036] Where n is an integer ≥ 2, for example, it can be 2, 3, 4, 5, or 6, etc.

[0037] Preferably, the preparation method of the chain extender includes: mixing maleimide-based phenol and furfuryl alcohol with dioxane and then performing a DA cycloaddition reaction, concentrating and drying the reaction product to obtain the chain extender.

[0038] In this invention, the chain extender prepared by the specific method described above can enhance the tensile strength of the cured polyurethane coating film and improve its elastic modulus.

[0039] Preferably, the molar ratio of maleimide-based phenol, furfuryl alcohol and dioxane is (1-3):(1-2):(1-4).

[0040] The numbers “1-3” can be 1, 1.1, 1.3, 1.5, 1.7, 1.9, 2, 2.1, 2.3, 2.5, 2.7, 2.9, or 3, etc.

[0041] “1-2” can be 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9 or 2, etc.;

[0042] “1-4” can be 1, 1.1, 1.3, 1.5, 1.8, 2, 2.2, 2.5, 2.8, 3, 3.2, 3.5, 3.8 or 4, etc.

[0043] Preferably, the reaction is carried out in a constant temperature water bath.

[0044] Preferably, the temperature of the constant temperature water bath is 70-90℃, for example, it can be 70℃, 72℃, 74℃, 76℃, 78℃, 80℃, 82℃, 84℃, 86℃, 88℃ or 90℃, etc.

[0045] Preferably, the coupling agent comprises 3-aminopropyltriethoxysilane and / or monoalkoxy titanate.

[0046] Preferably, the coupling agent is a combination of 3-aminopropyltriethoxysilane and monoalkoxytitanate.

[0047] Preferably, the mass ratio of 3-aminopropyltriethoxysilane to monoalkoxytitanate is 1:(0.1-0.5), for example, it can be 1:0.1, 1:0.15, 1:0.2, 1:0.25, 1:0.3, 1:0.35, 1:0.4, 1:0.45 or 1:0.5, etc.

[0048] Preferably, the curing agent comprises 4,4′-diphenylmethane diisocyanate prepolymer.

[0049] Preferably, the raw materials for preparing the bio-based modified polyurethane resin coating further include UV stabilizers and / or flame retardants.

[0050] Preferably, the raw materials for preparing the bio-based modified polyurethane resin coating further include 0.5-2 parts by weight of UV stabilizer and 1-3 parts by weight of flame retardant.

[0051] The amount of the UV-resistant agent can be 0.5 parts, 0.6 parts, 0.7 parts, 0.8 parts, 0.9 parts, 1 part, 1.1 parts, 1.2 parts, 1.3 parts, 1.4 parts, 1.5 parts, 1.6 parts, 1.7 parts, 1.8 parts, 1.9 parts, or 2 parts, etc.

[0052] The amount of flame retardant added can be 1 part, 1.2 parts, 1.5 parts, 1.8 parts, 2 parts, 2.2 parts, 2.5 parts, 2.8 parts, or 3 parts, etc.

[0053] Preferably, the flame retardant comprises polybutylene succinate.

[0054] The polybutylene succinate described in this invention is a bio-based polymer material that can improve the flame retardancy of coatings. By adding polybutylene succinate to the polyurethane coating, the material can have good flame retardancy.

[0055] Preferably, the UV stabilizer is a composite of lignin copolymer and silica.

[0056] As a preferred technical solution of the present invention, the use of the above-mentioned specific UV stabilizer can significantly improve the weather resistance of the polyurethane coating of the present invention.

[0057] Preferably, the mass ratio of the lignin copolymer to silica is 1:(2-5), for example, it can be 1:2, 1:2.1, 1:2.3, 1:2.5, 1:2.8, 1:3, 1:3.2, 1:3.5, 1:3.8, 1:4, 1:4.2, 1:4.5, 1:4.8 or 1:5, etc.

[0058] Preferably, the lignin copolymer is prepared by graft polymerization of pre-hydrolyzed lignin, methacryloyloxyethyltrimethylammonium chloride, acrylamide and potassium persulfate.

[0059] Preferably, the mass ratio of the pre-hydrolyzed lignin, methacryloyloxyethyltrimethylammonium chloride and acrylamide is (1-3):(0.5-2):(1-4).

[0060] The numbers “1-3” can be 1, 1.1, 1.3, 1.5, 1.7, 1.9, 2, 2.1, 2.3, 2.5, 2.7, 2.9, or 3, etc.

[0061] "0.5-2" can be 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9 or 2, etc.

[0062] “1-4” can be 1, 1.1, 1.2, 1.3, 1.5, 1.8, 2, 2.2, 2.5, 2.8, 3, 3.2, 3.5, 3.8 or 4, etc.

[0063] Preferably, the amount of potassium persulfate added is 5-20 mmol / L, for example, it can be 5 mmol / L, 6 mmol / L, 8 mmol / L, 10 mmol / L, 12 mmol / L, 15 mmol / L, 17 mmol / L, 19 mmol / L or 20 mmol / L, etc.

[0064] All the specific point values ​​within the above range can be selected, and will not be elaborated on here.

[0065] In a second aspect, the present invention provides a method for preparing a bio-based modified polyurethane resin coating as described in the first aspect, the method comprising: mixing and dispersing a polymer of polyester polyol, acrylate, trimethylolpropane, microcrystalline cellulose, dimethyl 4,4'-biphenyl dicarboxylate, ω-undecyl amino acid, polybutylene succinate, isosorbide, a chain extender, a coupling agent, a curing agent, and an anti-ultraviolet agent to obtain the bio-based modified polyurethane resin coating.

[0066] Thirdly, the present invention provides the application of a bio-based modified polyurethane resin coating as described in the first aspect in furniture, buildings or machinery.

[0067] Compared with the prior art, the present invention has the following beneficial effects:

[0068] (1) The polyurethane coating of the present invention has both excellent hardness and flexibility, smooth and glossy appearance, tensile strength in the range of 16-20MPa, hardness of 4H, adhesion of 0 grade, flame retardancy of FV-0, film flexibility of 1mm, hydrophobic angle of more than 109°, and excellent acid and alkali resistance and salt resistance. In addition, the polyurethane coating has the characteristic of fast curing and can be continuously sprayed on any curved surface, vertical surface and top surface without sagging.

[0069] (2) The polyurethane coating provided by the present invention can be prepared by mixing and dispersing the components. The process route is simple and can be promoted on a large scale. Detailed Implementation

[0070] To further illustrate the technical means and effects of the present invention, the following describes the technical solution of the present invention in conjunction with preferred embodiments of the present invention. However, the present invention is not limited to the scope of the embodiments.

[0071] The following are some of the material and grade information involved in the embodiments and comparative examples:

[0072]

[0073]

[0074] The structural formula of the polymer of isosorbide used is:

[0075] Where n = 2.

[0076] All other raw materials can be used as long as they are purchased from authorized distributors.

[0077] Preparation Example 1

[0078] This preparation example provides an ω-undecanoic acid. The preparation method of the ω-undecanoic acid is as follows: methyl ricinoleate, which is produced by alcoholysis of castor oil and methanol at a mass ratio of 1:1, is converted into heptanal and undecenoic acid methyl ester by high-temperature pyrolysis at 550℃ for 30 min. Then, undecenoic acid methyl ester is further hydrolyzed to generate undecenoic acid. Undecenoic acid is converted into bromoundecanoic acid by hydrogen bromide treatment under the action of benzoyl tert-butyl peroxide (the mass ratio of undecenoic acid to benzoyl tert-butyl peroxide is 100:1, and the peroxide treatment time is 5 h). The mass ratio of undecenoic acid to hydrogen bromide is 1:2. Finally, bromoundecanoic acid and ammonia are reacted at a mass ratio of 1:4 for 100 h to obtain ω-undecanoic acid.

[0079] Preparation Example 2

[0080] This preparation example provides a chain extender, which is prepared by the following method:

[0081] (1) Maleimide-based phenol and furfuryl alcohol were added to a reaction vessel containing dioxane (DO) (the molar ratio of maleimide-based phenol, furfuryl alcohol and dioxane was 1:1:1) to obtain a homogeneous mixed solution.

[0082] (2) After adding the magnetic particle, nitrogen gas was introduced to purge the air for 2 minutes and then the reaction vessel was sealed. The sealed reaction vessel was placed in a constant temperature water bath at 80°C and heated to carry out the DA cycloaddition reaction for 24 hours.

[0083] (3) The product after the reaction is completed is concentrated by rotary evaporation under reduced pressure and the solvent is recovered. Then, it is dissolved in acetone and concentrated to obtain the product. Then, it is precipitated with ice-cold ether. After repeated dissolution, concentration and precipitation three times, the precipitate is dried in a vacuum oven to obtain the product.

[0084] Preparation Example 3

[0085] This preparation example provides an anti-ultraviolet agent, which is a composite of lignin copolymer and silica in a mass ratio of 1:2;

[0086] The lignin copolymer was prepared by graft polymerization of pre-hydrolyzed lignin, methacryloyloxyethyltrimethylammonium chloride, acrylamide, and potassium persulfate at a pH of 7.5±0.5 and a temperature of 65°C for 2 hours; wherein the mass ratio of pre-hydrolyzed lignin, methacryloyloxyethyltrimethylammonium chloride, and acrylamide was 1:0.5:1.2, and the reaction concentration of potassium persulfate initiator was approximately 10 mmol / L.

[0087] Example 1

[0088] This embodiment provides a bio-based modified polyurethane resin coating. The components of the bio-based modified polyurethane, by weight, are: 35 parts polyester polyol, 25 parts acrylate, 7 parts trimethylolpropane, 2 parts microcrystalline cellulose, 4 parts dimethyl 4,4'-biphenyl dicarboxylate, 6 parts ω-undecanoic acid from Preparation Example 1, 2 parts polybutylene succinate, 6 parts isosorbide polymer, 3 parts chain extender from Preparation Example 2, 2 parts coupling agent (3-aminopropyltriethoxysilane and monoalkoxy titanate in a mass ratio of 3:1), 1 part 4,4'-diphenylmethane diisocyanate prepolymer, and 1.5 parts UV stabilizer from Preparation Example 3.

[0089] The preparation method of the bio-based modified polyurethane resin coating is as follows:

[0090] Polyester polyol, acrylate, and trimethylolpropane are added to a reaction vessel and stirred thoroughly with a mixer. The mixture is heated to 90°C, then ω-undecain amino acid is added and stirred until homogeneous. Microcrystalline cellulose, dimethyl 4,4'-biphenyl dicarboxylate, polybutylene succinate, isosorbide, chain extender, coupling agent, and UV stabilizer are then added and the reaction continues for 1 hour. The mixture is then kept at 80°C for at least 4 hours. Finally, a curing agent is added and stirred until homogeneous to obtain the final product.

[0091] Example 2

[0092] This embodiment provides a bio-based modified polyurethane resin coating. The components of the bio-based modified polyurethane, by weight, are: 32 parts polyester polyol, 28 parts acrylate, 6 parts trimethylolpropane, 4 parts microcrystalline cellulose, 3 parts dimethyl 4,4'-biphenyl dicarboxylate, 7 parts ω-undecanoic acid from Preparation Example 1, 2.5 parts polybutylene succinate, 7 parts isosorbide polymer, 2 parts chain extender from Preparation Example 2, 1.5 parts coupling agent (3-aminopropyltriethoxysilane and monoalkoxy titanate in a mass ratio of 2:1), 1.5 parts 4,4′-diphenylmethane diisocyanate prepolymer, and 1.5 parts UV stabilizer from Preparation Example 3.

[0093] The preparation method of the bio-based modified polyurethane resin coating:

[0094] Polyester polyol, acrylate, and trimethylolpropane are added to a reaction vessel and stirred thoroughly with a mixer. The mixture is heated to 100°C, then ω-undecain amino acid is added and stirred until homogeneous. Microcrystalline cellulose, dimethyl 4,4'-biphenyl dicarboxylate, polybutylene succinate, isosorbide, chain extender, coupling agent, and UV stabilizer are then added and the reaction continues for 1 hour. The mixture is then kept at 80°C for at least 4 hours. Finally, a curing agent is added and stirred until homogeneous to obtain the final product.

[0095] Example 3

[0096] This embodiment provides a bio-based modified polyurethane resin coating. The components of the bio-based modified polyurethane, by weight, are: 38 parts polyester polyol, 23 parts acrylate, 9 parts trimethylolpropane, 2 parts microcrystalline cellulose, 5 parts dimethyl 4,4'-biphenyl dicarboxylate, 5 parts ω-undecanoic acid from Preparation Example 1, 1.5 parts polybutylene succinate, 5 parts isosorbide polymer, 2.5 parts chain extender from Preparation Example 2, 1 part coupling agent, 0.5 parts 4,4′-diphenylmethane diisocyanate prepolymer, and 1 part UV stabilizer from Preparation Example 3.

[0097] The preparation method of the bio-based modified polyurethane resin coating is as follows:

[0098] Polyester polyol, acrylate, and trimethylolpropane are added to a reaction vessel and stirred thoroughly with a mixer. The mixture is heated to 100°C, then ω-undecain amino acid is added and stirred until homogeneous. Microcrystalline cellulose, dimethyl 4,4'-biphenyl dicarboxylate, polybutylene succinate, isosorbide, chain extender, coupling agent, and UV stabilizer are then added and the reaction continues for 1 hour. The mixture is then kept at 80°C for at least 4 hours. Finally, a curing agent is added and stirred until homogeneous to obtain the final product.

[0099] Example 4

[0100] This embodiment provides a bio-based modified polyurethane resin coating. The only difference between the bio-based modified polyurethane and that in Example 1 is that the raw materials do not include an anti-UV agent. The reduction is made up by polyester polyol. The remaining components and proportions are the same as in Example 1, and the preparation method is the same as in Example 1.

[0101] Example 5

[0102] This embodiment provides a bio-based modified polyurethane resin coating. The only difference between the bio-based modified polyurethane and that in Example 1 is that the UV stabilizer is silicon dioxide, and the amount of UV stabilizer added remains unchanged. The remaining components and proportions are the same as in Example 1, and the preparation method is the same as in Example 1.

[0103] Example 6

[0104] This embodiment provides a bio-based modified polyurethane resin coating. The only difference between the bio-based modified polyurethane and Example 1 is that the UV stabilizer is a lignin copolymer (the preparation method is the same as in Example 3), and the amount of UV stabilizer added remains unchanged. The remaining components and proportions are the same as in Example 1, and the preparation method is the same as in Example 1.

[0105] Example 7

[0106] This embodiment provides a bio-based modified polyurethane resin coating. The only difference between the bio-based modified polyurethane and that in Example 1 is that an equal amount of isosorbide is used to replace the isosorbide polymer. The remaining components and proportions are the same as in Example 1, and the preparation method is the same as in Example 1.

[0107] Example 8

[0108] This embodiment provides a bio-based modified polyurethane resin coating. The only difference between the bio-based modified polyurethane and Example 1 is that an equal amount of polyamino chain extender (isophorone diamine) is used to replace the chain extender in Preparation Example 2 of this invention. The remaining components and proportions are the same as in Example 1, and the preparation method is the same as in Example 1.

[0109] Example 9

[0110] This embodiment provides a bio-based modified polyurethane resin coating. The only difference between the bio-based modified polyurethane and Example 1 is that an equal amount of castor oil is used to replace the ω-undecainine in the preparation example 1 of this invention. The remaining components and proportions are the same as in Example 1, and the preparation method is the same as in Example 1.

[0111] Example 10

[0112] This embodiment provides a bio-based modified polyurethane resin coating. The only difference between the bio-based modified polyurethane and that in Example 1 is that the coupling agent is 3-aminopropyltriethoxysilane, and the amount of coupling agent added remains unchanged. The remaining components and proportions are the same as in Example 1, and the preparation method is the same as in Example 1.

[0113] Example 11

[0114] This embodiment provides a bio-based modified polyurethane resin coating. The only difference between the bio-based modified polyurethane and that in Example 1 is that the coupling agent is a monoalkoxy titanate, and the amount of coupling agent added remains unchanged. The remaining components and proportions are the same as in Example 1, and the preparation method is the same as in Example 1.

[0115] Example 12

[0116] This comparative example provides a bio-based modified polyurethane resin coating. The only difference between the bio-based modified polyurethane and Example 1 is that polybutylene succinate is not added to the bio-based modified polyurethane resin coating. The reduction is made up by polyester polyol. The remaining components and proportions are the same as in Example 1, and the preparation method is the same as in Example 1.

[0117] Comparative Example 1

[0118] This comparative example provides a bio-based modified polyurethane resin coating. The only difference between the bio-based modified polyurethane and Example 1 is that the bio-based modified polyurethane resin coating does not contain microcrystalline cellulose. The amount of cellulose is reduced and allocated to trimethylolpropane, dimethyl 4,4'-biphenyl dicarboxylate and ω-undecanyl amino acid in proportion. The remaining components and proportions are the same as in Example 1, and the preparation method is the same as in Example 1.

[0119] Comparative Example 2

[0120] This comparative example provides a bio-based modified polyurethane resin coating. The only difference between the bio-based modified polyurethane and Example 1 is that the bio-based modified polyurethane resin coating does not contain trimethylolpropane. The amount of trimethylolpropane is distributed in parts by parts to microcrystalline cellulose, dimethyl 4,4'-biphenyl dicarboxylate and ω-undecanine. The remaining components and proportions are the same as in Example 1, and the preparation method is the same as in Example 1.

[0121] Comparative Example 3

[0122] This comparative example provides a bio-based modified polyurethane resin coating. The only difference between the bio-based modified polyurethane and Example 1 is that the bio-based modified polyurethane resin coating does not contain dimethyl 4,4'-biphenyl dicarboxylate. The amount of 4,4'-biphenyl dicarboxylate is reduced and allocated to microcrystalline cellulose, trimethylolpropane and ω-undecanine in proportion to the parts. The remaining components and proportions are the same as in Example 1, and the preparation method is the same as in Example 1.

[0123] Comparative Example 4

[0124] This comparative example provides a bio-based modified polyurethane resin coating. The only difference between the bio-based modified polyurethane and Example 1 is that ω-undecainine is not added to the bio-based modified polyurethane resin coating. The amount of ω-undecainine is allocated to microcrystalline cellulose, trimethylolpropane and dimethyl 4,4'-biphenyl dicarboxylate in proportion to the amount of ω-undecainine. The remaining components and proportions are the same as in Example 1. The preparation method is the same as in Example 1.

[0125] Test Example 1

[0126] The polyurethane coatings obtained in Examples 1-12 and Comparative Examples 1-4 were tested as follows, and the test results are shown in Table 1:

[0127] Test method:

[0128] 1. Determination of pencil hardness of lacquer film:

[0129] The pencil hardness test was performed using the manual method as specified in GB / T 6739-2006.

[0130] 2. Determination of paint film adhesion:

[0131] The cross-cut test method was adopted, and the determination was carried out according to the cross-cut test method in GB / T 9286-1998.

[0132] 3. Test methods for tensile properties

[0133] The tensile properties of the coating were tested using an AG-IC 100kN universal testing machine manufactured by SHIMADZU Corporation of Japan, with displacement measured using a TRview X optical extensometer. The tensile properties were tested according to the methods specified in GB / T 528—2009, "Determination of Tensile Stress-Strain Properties of Vulcanized Rubber or Thermoplastic Rubber".

[0134] 4. Determination of flexibility

[0135] The flexibility of the coating film is tested using a flexibility tester according to the method in GB / T 1731-93.

[0136] 5. Determination of the chemical resistance of paint film

[0137] Test the chemical properties of the coating film according to the method in ISO 2812-1-2007.

[0138] 6. Test of water resistance of paint film

[0139] The hydrophobicity angle of the coating was tested using a PT-705B video optical contact angle meter, and the test standards and methods were in accordance with GB / T 30693-2014.

[0140] 7. The flame retardancy test method is as follows:

[0141] A. Each group of specimens requires 5 specimens, which should be flat, smooth, and free of air bubbles. The specimens should be 130±3mm long, 13.0±0.3mm wide, and 3.0±0.2mm thick. The prepared specimens should be conditioned under standard climatic conditions for 48 hours.

[0142] B. Test Procedure: The specimen is vertically fixed in the specimen clamp, with 6mm of absorbent cotton placed at the top. A Bunsen burner is lit 150mm from the specimen, with the flame height adjusted to 20±2mm and a blue flame. The center of the Bunsen burner is positioned 10mm below the specimen, with the flame directed towards the center of the lower end. Timing begins. After applying the flame for 10 seconds, the flame source is removed, and the duration of flaming combustion is recorded. After the flaming combustion extinguishes, the flame is applied again for 10 seconds, and the duration of flaming and flameless combustion is recorded after the flame is removed.

[0143] C. Result Evaluation: The combustion performance of the specimens is defined as three levels: FV-0, FV-1, and FV-2.

[0144] V-0: The vertical sample stops burning within 10 seconds; no liquid droplets are allowed.

[0145] V-1: Vertical specimens must cease combustion within 30 seconds; no liquid droplets are allowed.

[0146] V-2: The vertical sample stops burning within 30 seconds; dripping of burning material is permitted.

[0147] The results are shown in Tables 1 and 2.

[0148] Table 1

[0149]

[0150] Table 2

[0151]

[0152]

[0153] As can be seen from the data in Tables 1 and 2, the paint film samples of Examples 1-3 have a smooth and glossy appearance, a tensile strength range of 16-20 MPa, a hardness of 4H, an adhesion rating of 0, a flame retardancy rating of FV-0, a film flexibility of 1 mm, a hydrophobic angle of over 109°, and excellent acid, alkali and salt resistance, indicating that the polyurethane coating of the present invention has excellent mechanical properties and flame retardancy.

[0154] As can be seen from Examples 4-6, the choice of the type of UV stabilizer affects the weather resistance of the polyurethane coating of the present invention.

[0155] As can be seen from Examples 7-11, the selection of coupling agent, ω-undecain, isosorbide polymer, and chain extender directly affects the mechanical properties of the polyurethane coating.

[0156] As can be seen from Example 12, the flame retardancy of the polyurethane coating of the present invention is significantly poor when polybutylene succinate is lacking.

[0157] As can be seen from Comparative Examples 1-4, when any one of trimethylolpropane, dimethyl 4,4'-biphenyldicarboxylate, and microcrystalline cellulose or ω-undecanine is missing, the mechanical properties of the coating decrease significantly. This demonstrates that the trimethylolpropane, dimethyl 4,4'-biphenyldicarboxylate, microcrystalline cellulose, and ω-undecanine described in this application work together synergistically to achieve the polyurethane coating with excellent mechanical strength of this invention.

[0158] The applicant declares that the technical solution of this invention is illustrated by the above embodiments, but this invention is not limited to the above embodiments, that is, it does not mean that this invention must rely on the above embodiments to be implemented. Those skilled in the art should understand that any improvements to this invention, equivalent substitutions of raw materials for the products of this invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of this invention.

[0159] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0160] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

Claims

1. A bio-based modified polyurethane resin coating, characterized in that, The raw materials for preparing the bio-based modified polyurethane resin coating include, by weight, 30-40 parts polyester polyol, 20-30 parts acrylate, 5-10 parts trimethylolpropane, 1-5 parts microcrystalline cellulose, 3-6 parts dimethyl 4,4'-biphenyl dicarboxylate, 4-8 parts ω-undecyl amino acid, 4-8 parts isosorbide polymer, 1-4 parts chain extender, 1-3 parts coupling agent, 0.1-2 parts 4,4′-diphenylmethane diisocyanate prepolymer, 0.5-2 parts UV stabilizer, and 1-3 parts flame retardant. The ω-undecanoic acid is generated by the cleavage of castor oil; The preparation of the ω-undecanoic acid includes the following steps: (1) Castor oil in a mass ratio of 1:(1-2) is alcoholyzed with methanol to produce methyl ricinoleate; (2) Methyl ricinoleate is cleaved into heptanal and undecenoic acid methyl ester at 450-550℃; (3) Hydrolyze undecenoic acid methyl ester to generate undecenoic acid; (4) Undecenoic acid is reacted with hydrogen bromide under the action of peroxide to generate bromoundecanoic acid, wherein the mass ratio of undecenoic acid to hydrogen bromide is 1:(1-3). (5) ω-undecanoic acid was prepared by reacting bromoundecanoic acid in a mass ratio of 1:(1-5) with ammonia. The peroxide includes any one or a combination of at least two of di-tert-butyl peroxide, di-tert-pentyl peroxide, benzoyl peroxide, or benzoyl tert-butyl peroxide. The polymeric chemical structure of isosorbide is: ， Where n is an integer ≥ 2; The chain extender is prepared by mixing maleimide-based phenol, furfuryl alcohol and dioxane in a molar ratio of (1-3):(1-2):(1-4) and carrying out a DA cycloaddition reaction in a constant temperature water bath at 70-90℃. The reaction product is then concentrated and dried to obtain the chain extender.

2. The bio-based modified polyurethane resin coating as described in claim 1, characterized in that, The raw materials for preparing the bio-based modified polyurethane resin coating include, by weight, 32-38 parts of polyester polyol, 23-28 parts of acrylate, 6-9 parts of trimethylolpropane, 2-4 parts of microcrystalline cellulose, 3-5 parts of dimethyl 4,4'-biphenyl dicarboxylate, 5-7 parts of ω-undecyl amino acid, 5-7 parts of isosorbide polymer, 2-3 parts of chain extender, 1-2 parts of coupling agent, 0.5-1.5 parts of 4,4′-diphenylmethane diisocyanate prepolymer, 0.5-2 parts of UV stabilizer, and 1-3 parts of flame retardant.

3. The bio-based modified polyurethane resin coating according to claim 1, characterized in that, The coupling agent is a combination of 3-aminopropyltriethoxysilane and monoalkoxytitanate.

4. The bio-based modified polyurethane resin coating according to claim 3, characterized in that, The mass ratio of 3-aminopropyltriethoxysilane to monoalkoxytitanate is 1:(0.1-0.5).

5. The bio-based modified polyurethane resin coating according to claim 1, characterized in that, The flame retardant includes polybutylene succinate.

6. The bio-based modified polyurethane resin coating according to claim 1, characterized in that, The UV inhibitor is a complex of lignin copolymer and silicon dioxide.

7. The bio-based modified polyurethane resin coating according to claim 6, characterized in that, The mass ratio of the lignin copolymer to silica is 1:(2-5).

8. The bio-based modified polyurethane resin coating according to claim 6 or 7, characterized in that, The lignin copolymer is prepared by graft polymerization of pre-hydrolyzed lignin, methacryloyloxyethyltrimethylammonium chloride, acrylamide and potassium persulfate.

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