A thermosetting bio-based polyurethane antibacterial powder coating and a preparation method thereof

Abstract

The application discloses a thermosetting bio-based polyurethane antibacterial powder coating, which comprises 3-100 parts of rosin-based modified polyol, 0-80 parts of toughening resin, 5-35 parts of curing agent, 0.001-1 part of catalyst, 30-100 parts of modified red mud powder, 0.5-3 parts of leveling agent, 0.2-2 parts of nano antibacterial agent and 0-20 parts of pigment; wherein the rosin-based modified polyol is one or more of hydrogenated rosin alcohol, hydrogenated rosin acid (1-chloro-2-hydroxy) propyl ester, propylene pimaric acid di(1-chloro-2-hydroxy) propyl ester, propylene pimaric alcohol, maleic pimaric alcohol and maleic pimaric acid tri(1-chloro-2-hydroxy) propyl ester. The application provides a thermosetting bio-based polyurethane antibacterial powder coating and a preparation method thereof, which can improve the hardness, adhesion, heat resistance, flexibility and hydrophobicity of the existing polyurethane powder coating, improve the comprehensive performance of the existing antibacterial powder coating and prolong the service life of the coating.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the technical field of antibacterial powder coatings, and particularly relates to a thermosetting bio-based polyurethane antibacterial powder coating and a preparation method thereof. BACKGROUND

[0002] Powder coating is a solid powder synthetic resin coating composed of solid resin and pigment, filler and additive, etc. It uses air as the dispersion medium and has the characteristics of no solvent pollution, 100% film formation and low energy consumption. With the continuous improvement of the low content requirement of volatile organic compounds (VOCs) in the coating industry in recent years, the application of powder coating is increasingly valued, and the use field is constantly breaking through. In order to protect the health of the people, high-efficiency, long-acting and environmentally friendly antibacterial powder coatings are used on the surface of various furniture, appliances and household goods in the living environment, which can cut off the transmission channel of bacteria and viruses and avoid or reduce the transmission route of bacteria, so that antibacterial coatings are increasingly favored by consumers. However, due to the limitations of the application process of antibacterial materials in coatings, the upgrading of antibacterial powder coating production equipment and the performance of resins, the research and production of antibacterial powder coatings are still in the initial stage of development, and breakthroughs are urgently needed.

[0003] At present, vigorously developing low-carbon, green and environmentally friendly materials has become an important development direction of the chemical industry, and one of the important ways to develop new green high-performance materials is to replace petroleum-based materials with biomass raw materials. As a bio-based material, rosin is applied early, which is a mixture composed of tricyclic diterpene resin acids with hydrogenated phenanthrene structure, mainly including rosin acid, abietic acid, and a small part of fatty acid and neutral substances. Because the hydrogenated phenanthrene ring structure of rosin acid is similar to that of some petroleum-based aliphatic and aromatic compounds, it has great potential in replacing petroleum-based compounds to synthesize polyurethane.

[0004] Therefore, rosin as the main raw material applied in the preparation of coatings has broad development prospects. SUMMARY

[0005] Therefore, the present disclosure provides a thermosetting bio-based polyurethane antibacterial powder coating and a preparation method thereof, so as to improve the comprehensive performance of the thermosetting polyurethane antibacterial powder coating, such as adhesion, hardness, heat resistance, hydrophobicity, corrosion resistance and the like.

[0006] The present disclosure includes the following technical solutions: a thermosetting bio-based polyurethane antibacterial powder coating, comprising:

[0007] 3-100 parts of rosin-based modified polyol, 0-80 parts of toughening resin, 5-35 parts of curing agent, 0.001-1 part of catalyst, 30-100 parts of modified red mud powder, 0.5-3 parts of leveling agent, 0.2-2 parts of nano antibacterial agent, and 0-20 parts of pigment;

[0008] wherein the rosin-based modified polyol is one or more of hydrogenated rosin alcohol, hydrogenated rosin acid (1-chloro-2-hydroxy) propyl ester, propenyl pimaric acid di(1-chloro-2-hydroxy) propyl ester, propenyl pimaric alcohol, maleopimaric alcohol, maleopimaric acid tri(1-chloro-2-hydroxy) propyl ester.

[0009] Preferably, the toughening resin is one or more mixture of polyol, carboxyl-terminated polyester resin, acrylate resin, wherein the polyol is preferably one or more of poly(1,3-propylene succinate)diol (PPSu), poly(butylene succinate)diol (PBSu), poly(1,3-propylene sebacate)diol (PPSe), poly(butylene sebacate)diol (PBSe).

[0010] Preferably, the curing agent is one or more mixture of diisocyanate, triisocyanate, tetraisocyanate, isocyanurate triglycidyl ester.

[0011] Preferably, the catalyst is one or more mixture of stannous octoate, dibutyltin dilaurate, bismuth iso-octoate.

[0012] The present application also provides a preparation method of the thermosetting bio-based polyurethane antibacterial powder coating,

[0013] (1) first mix the rosin-based modified polyol and the toughening resin uniformly, then add the curing agent and mix uniformly to obtain a resin premix;

[0014] (2) add the resin premix into a mixer, then sequentially add the modified red mud powder, the leveling agent, the nano antibacterial agent, and the pigment component, and finally add the catalyst, mix thoroughly, then pre-crush for 2-10 min, and then mix for 5-20 min to obtain a uniformly mixed raw material;

[0015] (3) put the uniformly mixed raw material obtained in step (2) into an extruder, heat and react in two stages, press into tablets, cool, and then crush into tablet pieces, wherein the temperature for reaction extrusion is 65-180℃, the first-stage reaction temperature is 65-110℃, and the second-stage reaction temperature is 110-180℃;

[0016] (4) grind the crushed tablet pieces in step (3) in an ACM grinder, and after cyclone separation and sieving, obtain an antibacterial powder coating with an average particle size of 35-40 um. The present application also provides a preparation method of the thermosetting bio-based polyurethane antibacterial powder coating, first mix the rosin-based modified polyol and the toughening resin uniformly, then add the curing agent and mix uniformly to obtain a resin premix;

[0017] The application provides a thermosetting bio-based polyurethane antibacterial powder coating and a preparation method thereof, which is prepared by taking rosin as a main raw material, converting carboxyl in the molecular structure into hydroxyl, and preparing a polyol containing a hydrogenophenanthrene ring structure, which can be used as a polyurethane modification raw material for powder coating, introducing the hydrogenophenanthrene ring structure of rosin structure into the polyurethane macromolecule, improving the hardness, adhesion, heat resistance, flexibility and hydrophobicity of the existing polyurethane powder coating, improving the comprehensive performance of the existing antibacterial powder coating, prolonging the service life of the coating, and further promoting the technical level improvement and sustainable development of the bio-based green coating, which is the development trend of future coating and has a broad development prospect.

[0018] It should be understood that the above general description and the following detailed description are only exemplary and explanatory, and cannot limit the disclosure of the application. BRIEF DESCRIPTION OF DRAWINGS

[0019] The drawings incorporated into the specification and forming a part thereof show embodiments consistent with the application and, together with the specification, serve to explain the principles of the application.

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the application or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced below. Obviously, for those skilled in the art, other drawings can also be obtained without creative labor on the basis of these drawings.

[0021] Figure 1 The preparation schematic diagram of hydrogenated rosin acid (1-chloro-2-hydroxy) propyl ester, propenyl pimaric acid di(1-chloro-2-hydroxy) propyl ester and maleopimaric acid tri(1-chloro-2-hydroxy) propyl ester provided by the application is shown in the figure.

[0022] Figure 2 The preparation schematic diagram of propenyl pimaric alcohol and maleopimaric alcohol provided by the application is shown in the figure. DETAILED DESCRIPTION

[0023] The exemplary embodiments will be described in detail herein with reference to the drawings. Unless otherwise indicated, the same numbers on the different drawings indicate the same or similar elements. The embodiments described in the following exemplary embodiments are not meant to represent all embodiments consistent with the application. Rather, they are merely examples of methods consistent with some aspects of the application as detailed in the appended claims.

[0024] In order to solve the increasingly prominent problems among population, resources and environment, promote the development of bio-based green high-performance coatings, and improve the comprehensive performance of existing thermosetting polyurethane antibacterial powder coatings such as adhesion, hardness, heat resistance, hydrophobicity, corrosion resistance and the like on the basis of simplifying production process and reducing production cost, and prolong the service life of thermosetting polyurethane antibacterial powder coatings, the present application provides a kind of thermosetting bio-based polyurethane antibacterial powder coating, which is polymerized by rosin-based modified polyol, toughening resin, curing agent, catalyst, modified red mud powder, leveling agent, nano antibacterial agent and pigment, specifically, each component is as follows by mass:

[0025] a) the rosin-based modified polyol component is 3-100 parts, preferably 5-30 parts;

[0026] b) the toughening resin component is 0-80 parts, preferably 25-60 parts;

[0027] c) the curing agent component is 5-35 parts, preferably 10-25 parts;

[0028] d) the catalyst component is 0.001-1 part, preferably 0.01-0.5 part;

[0029] e) the modified red mud powder component is 30-100 parts, preferably 60-90 parts;

[0030] f) the leveling agent component is 0.5-3 parts, preferably 0.7-1.6 parts;

[0031] g) the nano antibacterial agent component is 0.2-2 parts, preferably 0.3-0.8 parts;

[0032] h) the pigment component is 0-20 parts, preferably 1-5 parts;

[0033] The rosin-based modified polyol is one or more of hydrogenated rosin alcohol, hydrogenated rosin acid (1-chloro-2-hydroxy) propyl ester, propylene pimaric acid di(1-chloro-2-hydroxy) propyl ester, propylene pimaric alcohol, male pimaric alcohol and male pimaric acid tri(1-chloro-2-hydroxy) propyl ester.

[0034] Specifically, the preparation method of the hydrogenated rosin acid (1-chloro-2-hydroxy) propyl ester, propylene pimaric acid di(1-chloro-2-hydroxy) propyl ester and male pimaric acid tri(1-chloro-2-hydroxy) propyl ester is as follows: dissolving rosin derivative in a non-aqueous solvent, adding epichlorohydrin, adding an accelerator, and reacting at 40-130℃ for 0.5-60h. After the reaction is completed, deionized water is added, and after sufficient oscillation, it is statically layered, the water layer is removed, and the oil container layer liquid is high-vacuum rotary evaporated to obtain the corresponding hydrogenated rosin acid (1-chloro-2-hydroxy) propyl ester, propylene pimaric acid di(1-chloro-2-hydroxy) propyl ester and male pimaric acid tri(1-chloro-2-hydroxy) propyl ester.

[0035] Further, the rosin derivative is hydrogenated rosin, propenyl pimaric acid, maleopimaric acid, or maleopimaric anhydride, and the ratio of carboxyl groups in the structure of the rosin derivative 1 to the epichlorohydrin is 1:1.05-1.50, and preferably 1:1.10-1.20;

[0036] Further, the amount of the non-aqueous solvent is 3-200 wt% of the mass of the rosin derivative 1, and preferably 10-50 wt%; and the amount of the promoter is 0.5-3.5 wt% of the total mass of the rosin derivative and the epichlorohydrin, and preferably 0.8-1.5 wt%.

[0037] Further, to improve the reaction conversion rate, the promoter is preferably added in multiple times, and the optimal number of times is 3-4 times, the first time is 1 / 2 of the total amount of the promoter, and the remaining times are 1 / 2 of the remaining amount of the promoter until all the promoter is added.

[0038] Further, the non-aqueous solvent is preferably one or more of toluene, xylene, ethyl acetate, butyl acetate, dichloromethane, dichloroethane, chloroform, carbon tetrachloride, trichloroethylene, and dichloroethylene.

[0039] Further, the promoter is one or more of tetrabutylammonium bromide, tetrabutylammonium chloride, tetrabutylammonium hydrogen sulfate, tetrabutylammonium fluoride, and tetrabutylammonium hydroxide, and preferably tetrabutylammonium bromide and tetrabutylammonium chloride.

[0040] The preparation method of the propenyl pimaric alcohol and the maleopimaric alcohol is as follows:

[0041] The propenyl pimaric acid or the maleopimaric acid is dissolved in a solvent, and under low temperature conditions, a reducing agent is slowly added under the protection of an inert gas, the reaction is carried out for 0.5-12 hours after the reducing agent is added, and then the temperature is increased to 40-80°C for 6-60 hours. After the reaction is completed, a quenching agent is used to quench the excess reducing agent, deionized water is then added, and then oscillation is carried out, and then filtration is carried out, and then vacuum filtration is carried out at 40-60°C until the constant weight. The non-aqueous solvent is added to the constant weight of the filtrate, oscillation is carried out, and then static layering is carried out, the water layer is removed, and then the oil layer liquid is subjected to high-vacuum rotary evaporation to obtain the viscous liquid product of the propenyl pimaric alcohol or the maleopimaric alcohol with a polyol structure.

[0042] The solvent is preferably one or more of anhydrous tetrahydrofuran, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, ethyl ether, ethyl butyl ether, dihexyl ether, and dipentyl ether; the inert gas is preferably one or a mixture of both of nitrogen and argon; the reducing agent is preferably one or a mixture of lithium aluminum hydride, sodium borohydride, potassium borohydride, and dibutyl aluminum hydride; and the quenching agent is preferably one or more of water, a sodium hydroxide aqueous solution, a sodium carbonate aqueous solution, a sodium bicarbonate aqueous solution, a hydrochloric acid solution, and an oleum solution.

[0043] The low temperature condition can be achieved by liquid nitrogen quick freezing method or by temperature control equipment to maintain the temperature condition of-10℃ to 15℃.

[0044] The toughening resin is one or more mixtures of polyol, carboxyl-terminated polyester resin, and acrylate resin. The polyol is preferably one or more of poly(1,3-propylene succinate)diol (PPSu), poly(butylene succinate)diol (PBSu), poly(1,3-propylene sebacate)diol (PPSe), and poly(butylene sebacate)diol (PBSe).

[0045] The curing agent is one or more mixtures of diisocyanate, triisocyanate, tetraisocyanate, and isocyanurate triglycidyl ester. The isocyanurate triglycidyl ester, 4,4-diphenylmethane diisocyanate, toluene diisocyanate, hexamethylene diisocyanate, 4,4',4"-triphenylmethane triisocyanate, dimethyltriphenylmethane tetraisocyanate, and tetraisocyanatosilane are preferred.

[0046] The catalyst is preferably one or more mixtures of stannous octoate, dibutyltin dilaurate, and bismuth isooctoate.

[0047] The modified red mud powder is prepared by the following steps: acid washing red mud with sulfuric acid to a pH value of 9.2-9.4, mixing with fatty alcohol polyoxyethylene ether ammonium sulfate, diethanolamide glycerol monostearate, sodium fatty acid methyl ester sulfonate, and N-trimethyl chitosan, and grinding. Preferably, the particle size of the modified red mud powder is greater than 300 mesh.

[0048] The leveling agent is PV88 leveling agent.

[0049] The nano-antibacterial agent is one or more mixtures of nano-silver ions and nano-silver-zinc composite ions.

[0050] The pigment is transparent blue or phthalocyanine green.

[0051] A thermosetting bio-based polyurethane antibacterial powder coating and a preparation method thereof, comprising the following steps:

[0052] (1) First, the rosin-based modified polyol is mixed uniformly with the toughening resin, and then the curing agent is added and mixed uniformly to obtain a resin premix;

[0053] (2) The resin premix is added to a mixer, and then the modified red mud powder, leveling agent, nano-antibacterial agent, and pigment component are sequentially added. Finally, the catalyst component is added, and the mixture is mixed thoroughly, followed by pre-crushing for 2-10 min and then mixing for 5-20 min to obtain a uniformly mixed raw material;

[0054] (3) Put the mixed raw materials prepared in step (2) into an extruder, heat and react in two stages, press into tablets, cool, and then crush into tablet pieces, wherein the temperature of the reaction extrusion is 65-180℃, the first stage reaction temperature is 65-110℃, preferably 70-110℃, and the second stage reaction temperature is 110-180℃, preferably 150-170℃;

[0055] (4) Put the crushed tablet pieces in step (3) into an ACM powder mill, mill, and then separate by cyclone and sieve to obtain an antibacterial powder coating with an average particle size of 35-40um.

[0056] The raw material information involved in the embodiments of the present application is as follows:

[0057] (1) Propylene pimaric acid:

[0058] The preparation of propylene pimaric acid is according to the literature (Wang Guoyun, Wang Zhenguo, Su Jianxiong. Preparation of acrylic acid pimaric polyester glass steel from rosin [J]. Plastics Industry, 1987, (01): 30-32+2.)

[0059] Add rosin and acrylic acid in a mass ratio of 4:25 into a three-necked flask, heat to 170℃ under nitrogen protection for 2h to isomerize the abietic acid type resin acid in the rosin to generate levopimaric acid. Then heat to 225℃ for 2h, since the conjugated double bond of levopimaric acid is S-cis, it has higher reactivity, so it reacts with the dieneophile-acrylic acid to prepare propylene pimaric acid in the form of light yellow transparent solid.

[0060] (2) Maleopimaric acid and maleopimaric anhydride:

[0061] Maleopimaric acid and maleopimaric anhydride are prepared by Diels-Alder reaction of rosin and maleic acid or maleic anhydride. According to the literature (Yin Hongmei, Guo Hong, Xu Feng, et al. Synthesis and application research of maleopimaric acid [J]. Journal of Shenyang College of Chemical Industry, 1998, (02): 15-21.)

[0062] Add a certain amount of rosin and maleic anhydride into a three-necked flask, heat to 180℃ for 4-5h, and cool to light yellow solid. Treat the powder with carbon tetrachloride for 2-3 times to remove unreacted rosin, and then treat with water for multiple times to remove unreacted maleic anhydride to obtain white powder product. The rosin and maleopimaric acid in the carbon tetrachloride treatment liquid can be recovered.

[0063] (3) Modified red mud powder:

[0064] Provided by Guangxi Fubaoxin Technology Co., Ltd.

[0065] According to the method disclosed in patent CN 111440515 A, the specific preparation method of the modified red mud powder is as follows:

[0066] 1) The red mud is pickled with 10-20wt% sulfuric acid to a pH value of 9.2-9.4, and then the pickled red mud is washed with water. After washing, the red mud is detected to have a pH value of 7.9-8.1, and then is pressed and filtered into clean red mud. The clean red mud is dried to a water content of ≤3.6%;

[0067] 2) The clean red mud prepared in step 1) is superfine ground, and after sieving, a clean red mud powder greater than 300 mesh is prepared;

[0068] 3) Add modifier a to the clean red mud powder prepared in step 2), the modifier a is composed of fatty alcohol polyoxyethylene ether ammonium sulfate and diethanolamide glycerol monostearate, the addition amount of the modifier a is 2.8-3.5% of the mass of the clean red mud powder, the mass ratio of the fatty alcohol polyoxyethylene ether ammonium sulfate and diethanolamide glycerol monostearate is 5.2-7.8:2.9-4.6, the temperature is controlled at 70-75°C, and stirring is carried out at a speed of 600-900r / min for 30-50min to prepare mixture a;

[0069] 4) Add the mixture a prepared in step 3) and modifier b to a mixing machine, the modifier b is composed of fatty acid methyl ester sodium sulfonate and N-trimethyl chitosan, the addition amount of the modifier b is 4.6-5.7% of the mass of the clean red mud powder, the mass ratio of the fatty acid methyl ester sodium sulfonate and N-trimethyl chitosan is 4.3-5.4:1.8-2.5, the temperature is controlled at 78-86°C, and stirring is carried out at a speed of 900-1300r / min for 32-45min to prepare mixture b;

[0070] 5) Dry the mixture b prepared in step 4) at a temperature of 50-53°C to a water content of ≤1.5%, and then superfine grind, and after sieving, a modified red mud powder greater than 300 mesh is prepared.

[0071] The rosin-based polyol derivative is used as a bio-based modified component of the thermosetting polyurethane antibacterial powder coating, and a high-performance thermosetting bio-based polyurethane antibacterial powder coating is prepared. Compared with the ordinary thermosetting polyurethane antibacterial powder coating, the thermosetting bio-based polyurethane antibacterial powder coating provided by the application not only applies bio-based materials to polyurethane modification to prepare bio-based polyurethane powder coating, has excellent green and environmental protection, but also introduces the bulky triphenyl ring structure of rosin into the polymer main chain, and is used in blending with other polyurethane materials, so that the hardness, heat resistance, hydrophobicity and other comprehensive performance of the polyurethane antibacterial powder coating are further improved, and the service life of the antibacterial powder coating is prolonged. In addition, experiments show that the thermosetting bio-based polyurethane antibacterial powder coating modified by the rosin-based polyol derivative has more excellent antibacterial property, the antibacterial durability is further improved, the comprehensive performance of the antibacterial powder coating is obviously improved, and it is proved that the modified polymer has a synergistic antibacterial effect with the antibacterial agent after the rosin-based polyol derivative is introduced.

[0072] The application has important scientific significance and practical application prospect for further promoting the greenization and functionalization of high-performance polyurethane powder coating.

[0073] The application will be further explained and described below in combination with specific examples, but is not used to limit the protection scope of the application.

[0074] Example 1

[0075] First, 3 parts by mass of hydrogenated rosin alcohol and 80 parts by mass of carboxyl-terminated polyester resin are fully mixed in a mixer, then 0.5 parts by mass of hexamethylene diisocyanate and 6.5 parts by mass of isocyanuric acid triglycidyl ester are added and mixed uniformly to obtain a resin premix; the resin premix is added to the mixer, then 60 parts by mass of modified red mud powder, 3 parts by mass of PV88 leveling agent, 2 parts by mass of nano silver-zinc composite ion antibacterial agent and 20 parts by mass of transparent blue pigment are sequentially added to the mixer containing the resin premix, and finally 0.001 parts by mass of dibutyltin dilaurate catalyst is added and fully mixed, followed by pre-crushing for 2 min and then mixing for 5 min to obtain uniformly mixed raw materials; the uniformly mixed raw materials are put into an extruder, and two-stage heating reaction extrusion is performed, wherein the first-stage reaction temperature is 100 DEG C, and the second-stage reaction temperature is 110 DEG C; the extruded material is pressed into a sheet, cooled, then crushed into a sheet material, and then the crushed sheet material is ground in an ACM powder mill, and after cyclone separation and screening, an antibacterial powder coating with an average particle size of 40 um is prepared.

[0076] Example 2

[0077] First, 50 parts by mass of hydrogenated rosin acid (1-chloro-2-hydroxy) propyl ester and 50 parts by mass of propylene pimaric acid di(1-chloro-2-hydroxy) propyl ester are mixed uniformly in a mixer, and then 15 parts by mass of 4,4-diphenylmethane diisocyanate and 20 parts by mass of toluene diisocyanate curing agent are mixed uniformly to obtain a resin premix; the resin premix is added to the mixer, and then 100 parts by mass of modified red mud powder, 2 parts by mass of PV88 leveling agent, 0.2 parts by mass of nano-silver ion antibacterial agent, and 10 parts by mass of phthalocyanine green pigment are sequentially added to the mixer containing the resin premix, and then 0.5 parts by mass of dibutyltin dilaurate and 0.5 parts by mass of bismuth octoate catalyst are added, followed by thorough mixing, pre-crushing for 10 minutes, and then mixing for 20 minutes to obtain a uniformly mixed raw material; the obtained uniformly mixed raw material is fed into an extruder, and is reacted and extruded in two stages, wherein the first-stage reaction temperature is 65°C, and the second-stage reaction temperature is 180°C; the extruded material is pressed into a sheet, cooled, and then crushed into a sheet material; the crushed sheet material is ground in an ACM grinder, and then separated by a cyclone and sieved to obtain an antibacterial powder coating with an average particle size of 35 um.

[0078] Example 3

[0079] First, 10 parts by mass of propylene pimaric acid di(1-chloro-2-hydroxy) propyl ester, 20 parts by mass of maleopimaric acid tri(1-chloro-2-hydroxy) propyl ester, and 20 parts by mass of maleopimaric alcohol are mixed uniformly in a mixer with 45 parts by mass of carboxyl-terminated polyethylene resin, and then 5 parts by mass of hexamethylene diisocyanate, 7 parts by mass of 4,4',4"-triphenylmethane triisocyanate, and 7 parts by mass of isocyanuric acid triglycidyl ester curing agent are mixed uniformly to obtain a resin premix; the resin premix is added to the mixer, and then 70 parts by mass of modified red mud powder, 1 part by mass of PV88 leveling agent, and 0.5 parts by mass of nano-silver ion antibacterial agent are sequentially added to the mixer containing the resin premix, and then 0.3 parts by mass of stannous octoate and 0.5 parts by mass of bismuth octoate catalyst are added, followed by thorough mixing, pre-crushing for 5 minutes, and then mixing for 10 minutes to obtain a uniformly mixed raw material; the obtained uniformly mixed raw material is fed into an extruder, and is reacted and extruded in two stages, wherein the first-stage reaction temperature is 105°C, and the second-stage reaction temperature is 150°C; the extruded material is pressed into a sheet, cooled, and then crushed into a sheet material; the crushed sheet material is ground in an ACM grinder, and then separated by a cyclone and sieved to obtain an antibacterial powder coating with an average particle size of 38 um.

[0080] Example 4

[0081] First, 5 parts by mass of maleopimarol, 15 parts by mass of maleopimaric acid tri(1-chloro-2-hydroxy)propyl ester and 40 parts by mass of carboxyl-terminated polyester resin are mixed in a mixer to obtain a resin premix; the resin premix is added into the mixer, then 30 parts by mass of modified red mud powder, 0.5 parts by mass of PV88 leveling agent, 0.3 parts by mass of nano-silver ion antibacterial agent, 1.5 parts by mass of transparent blue pigment and 0.5 parts by mass of phthalocyanine green pigment are sequentially added into the mixer containing the resin premix, and then 0.6 parts by mass of bismuth octoate catalyst is added, followed by mixing for 10 min and then mixing for another 8 min to obtain a mixed raw material; the mixed raw material is fed into an extruder, and then heated and reacted in two stages, wherein the first-stage reaction temperature is 90°C and the second-stage reaction temperature is 170°C; the extruded material is pressed into a sheet, cooled, and then crushed into a sheet material; the crushed sheet material is ground in an ACM grinder, and then separated by a cyclone and sieved to obtain an antibacterial powder coating with an average particle size of 37 um.

[0082] Example 5

[0083] First, 10 parts by mass of pimaric acid di(1-chloro-2-hydroxy)propyl ester and 60 parts by mass of carboxyl-terminated polyester resin are mixed in a mixer to obtain a resin premix; the resin premix is added into the mixer, then 70 parts by mass of modified red mud powder, 1.6 parts by mass of PV88 leveling agent, 0.4 parts by mass of nano-silver ion antibacterial agent, 3 parts by mass of transparent blue pigment are sequentially added into the mixer containing the resin premix, and then 0.05 parts by mass of bismuth octoate catalyst is added, followed by mixing for 6 min and then mixing for another 12 min to obtain a mixed raw material; the mixed raw material is fed into an extruder, and then heated and reacted in two stages, wherein the first-stage reaction temperature is 95°C and the second-stage reaction temperature is 110°C; the extruded material is pressed into a sheet, cooled, and then crushed into a sheet material; the crushed sheet material is ground in an ACM grinder, and then separated by a cyclone and sieved to obtain an antibacterial powder coating with an average particle size of 38 um.

[0084] Comparative Example 1

[0085] The difference between the present comparative example and Example 4 is that the present comparative example changes 5 parts by mass of maleopimarol, 15 parts by mass of maleopimaric acid tri(1-chloro-2-hydroxy)propyl ester to 20 parts by mass of carboxyl-terminated polyfatty acid resin, and changes 2 parts by mass of hexamethylene diisocyanate, 4 parts by mass of triphenylmethane tetraisocyanate, and 3 parts by mass of tetraisocyanatosilane curing agent to 3 parts by mass of isocyanuric acid triglycidyl ester.

[0086] Comparative Example 2

[0087] The difference between the present comparative example and Example 5 is that the present comparative example changes 10 parts by mass of pimaric acid di(1-chloro-2-hydroxy)propyl ester to 10 parts by mass of carboxyl-terminated polyfatty acid resin, and changes 2 parts by mass of hexamethylene diisocyanate curing agent to 0.5 parts by mass of isocyanuric acid triglycidyl ester curing agent.

[0088] The pencil hardness, adhesion, antibacterial property, and artificial weathering resistance of the antibacterial powder coating prepared in Examples 1-5 and Comparative Examples 1 and 2 were detected, wherein the pencil hardness was detected according to GB / T 6739-1998; the adhesion was detected according to GB / T 9286-2021 ISO 2409; the antibacterial property was detected according to GB / T 21866-2008; and the artificial weathering resistance was detected according to GB / T 1865-1997 ASTM G151, and the results are shown in Table 1 below.

[0089] Table 1 Performance detection results of the antibacterial powder coating prepared in Examples 1-5 and Comparative Examples 1 and 2

[0090]

[0091]

[0092] Other embodiments of the application will be apparent to those skilled in the art from consideration of the specification and practice of the application disclosed herein. It is intended that the specification and examples be considered as exemplary only, with the true scope and spirit of the application being indicated by the following claims.

[0093] It is to be understood that the application is not limited to the particulars described above and that various modifications and changes can be made in the application without departing from its scope. The scope of the application is limited only by the claims appended hereto.

Claims

1. A thermosetting bio-based polyurethane antibacterial powder coating, characterized in that: The components by mass include: 3-100 parts of rosin-based modified polyol, 0-80 parts of toughening resin, 5-35 parts of curing agent, 0.001-1 parts of catalyst, 30-100 parts of modified red mud powder, 0.5-3 parts of leveling agent, 0.2-2 parts of nano-antibacterial agent, and 0-20 parts of pigment; wherein the rosin-based modified polyol is one or more of propylene pinmarol and maleic pinmarol; or The rosin-based modified polyol is a mixture of one or more of hydrogenated abietic alcohol, hydrogenated abietic acid (1-chloro-2-hydroxy)propyl ester, di(1-chloro-2-hydroxy)propyl acrylopimarate, tri(1-chloro-2-hydroxy)propyl maleopimarate, and one or more of acrylopimarin and maleopimarin. The preparation method of the hydrogenated rosin acid (1-chloro-2-hydroxy)propyl ester, propylene pimaric acid di(1-chloro-2-hydroxy)propyl ester, and maleopimaric acid tri(1-chloro-2-hydroxy)propyl ester is as follows: hydrogenated rosin or propylene pimaric acid or maleopimaric acid are respectively dissolved in a non-aqueous solvent, epichlorohydrin and an accelerator are added, and the mixture is reacted at 40-130°C for 0.5-60 hours; after the reaction, deionized water is added, the mixture is shaken thoroughly, and the mixture is allowed to stand for separation, the water layer is removed, and the oil-containing layer liquid is subjected to high vacuum rotary evaporation to obtain the corresponding hydrogenated rosin acid (1-chloro-2-hydroxy)propyl ester, propylene pimaric acid di(1-chloro-2-hydroxy)propyl ester, and maleopimaric acid tri(1-chloro-2-hydroxy)propyl ester; The preparation method of propylene pimaric acid and maleopimaric acid is as follows: dissolving propylene pimaric acid or maleopimaric acid in a solvent, slowly adding a reducing agent under the protection of an inert gas at low temperature, reacting for 0.5 to 12 hours after the reducing agent is added, and then heating to 40 to 80° C. and reacting for 6 to 60 hours; After the reaction is completed, the excess reducing agent is quenched with a quenching agent, and then deionized water is added and the mixture is fully shaken. After filtration, vacuum filtration is performed at 40-60° C. to a constant weight. A non-aqueous solvent is added to the constant weight filtrate, and after sufficient shaking, the mixture is allowed to stand for separation, the water layer is removed, and the oil-containing layer liquid is subjected to high vacuum rotary evaporation to obtain a viscous liquid product having a polyol structure, namely, propylene pinimarol or maleopimarol.

2. The thermosetting bio-based polyurethane antibacterial powder coating according to claim 1, characterized in that: The toughening resin is a mixture of one or more of polyols, carboxyl-terminated polyester resins, and acrylate resins, wherein the polyol is one or more of poly(1,3-propylene succinate) diol, poly(butylene succinate) diol, poly(1,3-propylene sebacate) diol, and poly(butylene sebacate) diol.

3. The thermosetting bio-based polyurethane antibacterial powder coating according to claim 1, characterized in that: The curing agent is a mixture of one or more of diisocyanate, triisocyanate, tetraisocyanate and triglycidyl isocyanurate.

4. The thermosetting bio-based polyurethane antibacterial powder coating according to claim 1, characterized in that: The catalyst is a mixture of one or more of stannous octoate, dibutyltin dilaurate, and bismuth isooctanoate.

5. The method for preparing the thermosetting bio-based polyurethane antibacterial powder coating according to any one of claims 1 to 4, characterized in that: (1) First, the rosin-based modified polyol and the toughening resin are fully mixed, and then the curing agent is added and mixed evenly to obtain a resin premix; (2) Add the resin premix into the mixer, then add the modified red mud powder, leveling agent, nano antibacterial agent, pigment component in sequence, and finally add the catalyst, mix thoroughly, then pre-crush for 2-10 minutes, and then mix for 5-20 minutes to obtain a uniformly mixed raw material; (3) The uniformly mixed raw materials obtained in step (2) are fed into an extruder, and heated and reacted in two stages, extruded, tableted, and cooled, and then crushed into tablets, wherein the reaction extrusion temperature is 65-180°C, wherein the first stage reaction temperature is 65-110°C; the second stage reaction temperature is 110-180°C; (4) The flakes crushed in step (3) are placed in an ACM grinder for grinding, and after cyclone separation and screening, an antibacterial powder coating with an average particle size of 35-40 μm is obtained.

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