Bio-based coating for generator shell as well as preparation method and application of bio-based coating

Abstract

The invention relates to a bio-based coating for a generator shell as well as a preparation method and application of the bio-based coating. The bio-based coating comprises the following components in percentage by weight: 40-50% of modified rosin glyceride, 13-25% of modified ricinoleic anhydride, 12-35% of a bio-based solvent, 3-8% of filler and 2-6% of an anti-corrosion additive. The bio-based paint for the generator shell supports selection of multiple curing modes to form a coating, the construction efficiency is effectively improved, a user can select the corresponding curing mode according to the construction condition of the user, the bio-based paint has extremely high universality and flexibility, in addition, the formed coating has good temperature resistance, wear resistance, corrosion resistance and environmental protection performance, and the application prospect is wide. The comprehensive performance is excellent, and the protection requirement of the large-scale generator surface of a coal-fired unit can be met.

Description

Technical Field

[0001] The present invention relates to the technical field of coatings, and in particular to a bio-based coating for a generator housing and a preparation method and application thereof. Background Art

[0002] In the construction of power systems, large generators are indispensable core components that play a key role in industrial production and energy supply. However, these devices will inevitably encounter a series of problems such as corrosion, wear, high temperature and chemical erosion during long-term operation, which not only affect the performance of the generator, but also may shorten its service life.

[0003] In order to solve the above problems and extend the service life of the generator, a protective coating is usually applied on its surface. The coatings currently on the market are mainly divided into the following categories: (1) Traditional organic coatings: This type of coating is based on petroleum-based resins. Although it provides good protective performance, it has shortcomings in terms of environmental protection and sustainability; (2) Water-based coatings: Compared with traditional organic coatings, water-based coatings use water as a solvent or dispersion medium and have better environmental performance. However, water-based coatings are generally inferior to organic coatings in terms of temperature resistance and corrosion resistance; (3) High-solid coatings: This type of coating has a low solvent content, which reduces the emission of volatile organic compounds (VOCs) and improves environmental protection, but it has shortcomings in cost and construction performance; (4) Nano-composite coatings: By adding nanomaterials, this type of coating has been significantly improved in physical and chemical properties, but the high cost of nanomaterials and potential environmental health issues limit its widespread application.

[0004] Although the existing coatings suitable for coal-fired unit generator technology have made progress in terms of performance, with the rapid development of modern science and technology, the country has attached more and more importance to the energy-saving and environmental protection effects of coal-fired power plants. The coatings used in existing coal-fired power plants generally use traditional organic coatings. Although they provide good protection for the generator, they are not enough to cope with the increasingly severe environmental protection form. There is still a problem of insufficient environmental protection. Coatings containing harmful substances will pose a threat to the environment and human health after volatilization. Or, if coal-fired power plants choose coatings with good environmental protection and low pollution, due to the different construction conditions of each power plant, in most cases, only coatings with thermal curing conditions can be selected, but this usually requires a long curing time and high energy consumption. It is difficult for thermal power plants to flexibly select the most suitable curing method according to their own construction conditions, which not only increases costs, but also limits the possibility of efficiency improvement. Therefore, a coating that is both universal and environmentally friendly and can meet the protection needs of large coal-fired unit generators is needed. To this end, a bio-based coating for a generator housing and a preparation method and application thereof are provided to solve the above problems. Summary of the invention

[0005] In view of the deficiencies in the prior art mentioned in the background technology, the present invention proposes a bio-based coating for a generator housing and a preparation method and application thereof.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] A bio-based coating for a generator housing, characterized in that it comprises the following components in weight percentage: 40-50% of modified rosin glycerol ester, 13-25% of modified ricinoleic anhydride, 12-35% of a bio-based solvent, 3-8% of a filler, and 2-6% of an anti-corrosion additive;

[0008] Used to form coatings under any of the curing methods: thermal curing, UV curing, and electron beam curing.

[0009] Furthermore, the weight ratio of the modified rosin glycerol ester to the modified ricinoleic anhydride is 3:1.

[0010] Furthermore, the particle size of the filler is 20-100 nm.

[0011] Further, the bio-based solvent is any one or a combination of bio-based propylene glycol, bio-based butylene glycol and bio-based glycerol; and / or

[0012] The filler is any one or a combination of nano titanium dioxide, nano silicon dioxide and nano zirconium dioxide; and / or

[0013] The anti-corrosion additive is any one or a combination of zinc phosphate, zinc molybdate and zinc tungstate.

[0014] Furthermore, it also includes 0.5-2% of a rheology modifier, wherein the rheology modifier is hydroxyethyl cellulose; and / or

[0015] It also includes 0.1-1% of a stabilizer, wherein the stabilizer is any one or a combination of ammonium dodecyl sulfate, propylene glycol alginate and bis(1,2,2,6,6-pentylmethyl-4-piperidinyl) sebacate; and / or

[0016] It also includes 0.05-0.5% of a surfactant, wherein the surfactant is any one or a combination of polyoxyethylene (20) sorbitan monolaurate and fatty alcohol polyoxyethylene ether; and / or

[0017] It also contains 5-10% pigment.

[0018] To achieve the above object, the present invention adopts the following technical solutions:

[0019] A method for preparing a bio-based coating for a generator housing, the method being used to prepare any one of the bio-based coatings for a generator housing, comprising the following steps:

[0020] Step S 1 , mixing 40-50% of modified rosin glycerol ester and 12-35% of bio-based solvent to obtain a mixed solution;

[0021] Step S 2 , dispersing the mixed solution and 3-8% of filler to form a suspension;

[0022] Step S 3 3. Continue to add 13-25% of modified ricinoleic anhydride and 2-6% of anti-corrosion additive into the suspension to obtain the target coating.

[0023] Furthermore, the method further comprises the step of adjusting the construction viscosity:

[0024] Step S 4 , adding 0.1-1% stabilizer to the target coating, and adding 0.05-0.5% surfactant in portions;

[0025] The surfactant is added to the target coating at least once, 0.05% each time, until the construction viscosity is adjusted to 60-120 centipoise.

[0026] Further, 5 to 10% of the pigment is added in step S 2 Add together with 3-8% of the filler; and / or

[0027] 0.5-2% rheology modifier in step S 3 The modified ricinoleic anhydride is added together with 13-25% and 2-6% of the anti-corrosion additive.

[0028] To achieve the above object, the present invention adopts the following technical solutions:

[0029] A bio-based coating for a generator housing is a coating formed by coating and curing a bio-based coating for a generator housing; the bio-based coating for a generator housing is any one of the bio-based coatings for a generator housing described above.

[0030] In summary, compared with the prior art, the present invention has at least the following beneficial effects:

[0031] The present invention relates to a bio-based coating for a generator housing and a preparation method and application thereof, comprising the following components in weight percentage: 40-50% of modified rosin glycerol ester, 13-25% of modified ricinoleic anhydride, 12-35% of bio-based solvent, 3-8% of filler, and 2-6% of anti-corrosion additive; used to form a coating under any curing mode of thermal curing, ultraviolet curing, and electron beam curing. The bio-based coating for a generator housing prepared by the present invention is easy to induce a chemical reaction under the action of external energy. When curing, the modified rosin glycerol ester and the modified ricinoleic anhydride can generate a large number of free radicals and cross-linking sites with high reactivity. These free radicals can cooperate with the cross-linking sites to form a cross-linking network during curing, and have high reactivity. The modified ricinoleic anhydride stabilizes the activity of the free radicals through the synergistic effect with the modified rosin glycerol ester, so that the coating is quickly and controllably transformed from a liquid state to a solid coating. The bio-based coating for the generator casing in this application supports the selection of multiple curing methods to form the coating, which effectively improves the construction efficiency. Users can choose the corresponding curing method according to their own construction conditions. It has strong versatility and flexibility. In addition, the formed coating has good temperature resistance, wear resistance, corrosion resistance and environmental protection, and has excellent comprehensive performance, which can meet the protection needs of the surface of large generators of coal-fired units. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0033] Figure 1 A comparison of the free radical intensity during the curing process of Example 2 and Example 5 provided by the present invention

[0034] Figure 2 A comparison chart of the free radical intensity during the curing process of Example 3 and Example 6 provided by the present invention.

[0035] Figure 3 A comparison chart of the free radical intensity during the curing process of Example 4 and Example 7 provided by the present invention.

[0036] Figure 4 This is a comparison chart of the free radical intensity during the curing process of Examples 2-4 provided by the present invention. DETAILED DESCRIPTION

[0037] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions 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.

[0038] A bio-based coating for a generator housing, characterized in that it comprises the following components in weight percentage: 40-50% of modified rosin glycerol ester, 13-25% of modified castor oil anhydride, 12-35% of bio-based solvent, 3-8% of filler, and 2-6% of anti-corrosion additive, and is used to form a coating under any curing method of thermal curing, ultraviolet light curing, and electron beam curing. Among them, the modified rosin glycerol ester is a bio-based resin, the modified castor oil anhydride is a bio-based curing agent, the modified rosin glycerol ester has better adhesion performance, and the modified castor oil anhydride has good compatibility, and can be fully mixed with other components in the coating to form a uniform coating, ensuring the uniformity and stability of the coating.

[0039] In the present invention, the various curing methods of bio-based coatings for generator housings rely on the reaction of functional groups provided by modified rosin glycerol esters and modified ricinoleic anhydride to form a cross-linked network. Each curing method is adapted to different production environments and needs: thermal curing is suitable for traditional baking processes, suitable for conventional industrial environments, usually takes a long time (several hours), and is suitable for coatings of large generators that require high-temperature curing; UV curing greatly improves the curing efficiency with its fast curing characteristics, and the UV curing speed is extremely fast (several seconds to several minutes), which is suitable for scenes with high requirements for coating quality and high construction efficiency; and electron beam curing not only does not require additional photoinitiators, but also has a further improvement in curing speed compared to UV curing (usually completed within a few seconds), and has lower energy consumption, which is particularly suitable for the rapid construction of thick coatings or complex-shaped generators. The versatility of multiple curing methods allows thermal power plants to select the most suitable curing method according to specific production conditions, effectively controlling energy consumption and coating costs, which is particularly important for generator housings that need to maintain stability and reliability for a long time under harsh working conditions. Users can choose the corresponding curing method according to their own construction conditions, which has strong versatility and flexibility.

[0040] Specifically, when using thermal curing, the modified rosin glycerol ester provides hydroxyl groups (-OH) and unsaturated carbon-carbon double bonds (C=C), and the modified castor oil anhydride provides several carboxyl groups (-COOH). Under the high temperature of thermal curing, the esterification reaction between the hydroxyl groups (-OH) and the carboxyl groups (-COOH) forms a stable ester bond (-COO-) and then forms a cross-linked network. The unsaturated carbon-carbon double bonds (C=C) are decomposed into free radicals by heat, and free radical polymerization occurs to induce double bond crosslinking, further improving the strength and density of the cured coating. When using the ultraviolet light curing method, both the modified rosin glycerol ester and the modified castor oil anhydride contain abundant unsaturated carbon-carbon double bonds (C=C), and because ultraviolet light curing requires a photoinitiator, the modified rosin glycerol ester also contains a photosensitive group (carbonyl), which can absorb ultraviolet light and decompose to generate free radicals. Under the action of ultraviolet light, ultraviolet light excites the unsaturated carbon-carbon double bonds (C=C) and the photosensitive groups of the modified rosin glycerol ester to generate free radicals, and these free radicals then attack the unsaturated carbon-carbon double bonds (C=C) of the modified rosin glycerol ester and the modified castor oil anhydride, triggering the cross-linking reaction of the carboxyl group (-COOH) and the resin monomer, and the modified castor oil anhydride also contains an aromatic ring structure, which can absorb ultraviolet light, excite electrons after π→π* transition, and assist in generating free radical reactions. When electron beam curing is used, the modified rosin glycerol ester provides hydroxyl groups (-OH) and unsaturated carbon-carbon double bonds (C=C), and the modified castor oil anhydride provides unsaturated carbon-carbon double bonds (C=C). The high-speed electron beam directly acts on the unsaturated carbon-carbon double bonds (C=C) and hydroxyl groups (-OH) to generate free radicals or ionic intermediates, which trigger cross-linking polymerization of carboxyl groups (-COOH) and resin monomers. Under the action of the above multiple curing processes, the free radicals can quickly polymerize to form a cross-linked structure, so that the coating can be quickly and controllably transformed from a liquid state to a solid coating.

[0041] Furthermore, modified rosin glycerol ester (bio-based resin) as the main film-forming substance has excellent adhesion and chemical resistance; the combination of modified castor oil anhydride and modified rosin glycerol ester ensures that the paint can be quickly cured and has long-term stability when it is brushed into a coating; the bio-based solvent is used to adjust the concentration of the paint so that it is easy to apply when it is subsequently applied as a coating and can form a smooth surface of the coating, is non-volatile, and facilitates uniform mixing of the various raw materials of the coating; the filler is used to improve the wear resistance of the coating when it is cured into a coating; the anti-corrosion additive is used to improve the corrosion resistance of the coating and protect the metal surface of the generator from corrosion.

[0042] It is worth noting that most of the coating components of the present invention use bio-based materials, which are derived from renewable resources such as plants grown through photosynthesis and non-food crops, from which chemical monomers required for the synthesis of polymer raw materials are extracted, and then polymerized into the required bio-based materials through microbial or chemical synthesis methods, which have extremely high environmental protection. This process reduces dependence on fossil fuels and produces less greenhouse gas emissions, which helps to reduce the carbon dioxide content in the atmosphere, reduces the carbon footprint in the production process, and conforms to the development trend of green environmental protection. For example, compared with the epoxy resin commonly used in traditional coatings, bisphenol A and epichlorohydrin are polycondensed under the action of NaOH, wherein bisphenol A is condensed with phenol and acetone in the presence of a catalyst, wherein phenol is a part of coal tar and belongs to non-renewable resources. In addition, compared with the organic solvents widely used in existing coatings containing volatile organic compounds VOCs, the coating of the present invention does not contain or significantly reduces volatile organic compounds VOCs, and has little impact on the environment and human health.

[0043] Furthermore, in certain embodiments of the present invention, the weight ratio of modified rosin glycerol ester and modified castor oil anhydride is 3:1. When the ratio is lower than 3:1, it will cause the subsequent conversion to a coating that needs to be cured to be too sufficient, which will cause the coating surface to peel, thereby affecting the protectiveness of the coating; when the ratio is higher than 3:1, incomplete curing will occur, thereby affecting the performance of the coating. Moreover, when the ratio is 3:1, the number of carboxyl groups (-COOH) in the modified rosin glycerol ester and the modified castor oil anhydride and the number of unsaturated carbon-carbon double bonds (C=C) are in an optimized state, so that after each free radical is generated, there are enough carboxyl groups (-COOH) to participate in cross-linking, reducing free radical annihilation, and making the cured network more uniform. Therefore, the weight ratio of modified rosin glycerol ester and modified castor oil anhydride in the present invention is most preferably 3:1.

[0044] In certain embodiments of the present invention, in order to make the subsequent coating have a good anti-fouling surface, the particle size of the filler is preferably 20-100 nm.

[0045] In certain embodiments of the present invention, the bio-based solvent is preferably any one or a combination of bio-based propylene glycol, bio-based butylene glycol and bio-based glycerol. Among them, bio-based propylene glycol has the best compatibility and can effectively dissolve and disperse other materials in the coating formulation to avoid problems such as stratification and precipitation. Therefore, the bio-based solvent in the present invention is most preferably bio-based propylene glycol.

[0046] In certain embodiments of the present invention, the filler is preferably any one or a combination of nano titanium dioxide, nano silicon dioxide and nano zirconium dioxide. Among them, nano titanium dioxide has strong adhesion, is not easy to undergo chemical changes, has high stability when added to the coating, and will not undergo unnecessary chemical reactions with other ingredients. Therefore, the filler in the present invention is most preferably nano titanium dioxide.

[0047] In certain embodiments of the present invention, the anti-corrosion agent can be any anti-corrosion agent known to those skilled in the art, without any special restrictions. Preferably, the anti-corrosion agent is any one or a combination of zinc phosphate, zinc molybdate and zinc tungstate. Among them, zinc phosphate can provide sacrificial anode protection in an environment containing water and oxygen. Since the material of the generator housing is generally made of iron-containing materials, and zinc is a more active metal that is more easily corroded than iron, a layer of zinc phosphate will be formed on the surface of the generator iron housing, and zinc will be corroded first, thereby protecting the generator housing from corrosion; and the zinc phosphate coating will form a hard film after drying, which can act as a barrier to prevent corrosive media such as water and oxygen from contacting the surface of the generator housing, slowing down the corrosion process. Therefore, the most preferred anti-corrosion agent in the present invention is zinc phosphate.

[0048] In certain embodiments of the present invention, 0.5-2% of a rheology modifier is added to the bio-based coating for the generator housing to improve the rheology of the coating so that it maintains good leveling, ensuring the uniformity of the coating when applied as a coating and the flatness after construction. The rheology modifier in the present invention is hydroxyethyl cellulose, which is a kind of biomass and can increase the viscosity of the coating of the present invention, so that the coating has better anti-sagging and anti-settling properties, is easy to construct and can further improve the uniformity of the coating. In addition, hydroxyethyl cellulose helps to improve the stability of the coating during storage and prevent viscosity changes or stratification caused by long-term storage.

[0049] In certain embodiments of the present invention, 0.1 to 1% of a stabilizer is added to the bio-based coating for the generator housing to further improve the stability of the coating, reduce the overall activity of the coating, and reduce the cracking phenomenon of the coating when it is applied as a coating. The stabilizer in the present invention is any one or a combination of several of ammonium dodecyl sulfate, propylene glycol alginate, and bis(1,2,2,6,6-pentylmethyl-4-piperidyl) sebacate. Among them, ammonium dodecyl sulfate, as a cationic surfactant, can effectively stabilize the emulsion and suspension produced in the process of preparing the coating, prevent the phase separation of the coating during storage and use, and can also be used to control the generation of foam in the coating, especially effectively reduce the generation of foam during stirring and mixing. Therefore, the stabilizer in the present invention is most preferably ammonium dodecyl sulfate.

[0050] In certain embodiments of the present invention, 0.05-0.5% of a surfactant is added to the bio-based coating for the generator housing to change the surface tension of the coating, which helps to evenly disperse the materials inside the coating, and then adjust the construction viscosity of the coating to an appropriate range of 60-120 centipoise. The surfactant in the present invention is any one or a combination of polyoxyethylene (20) sorbitan monolaurate and fatty alcohol polyoxyethylene ether. Among them, polyoxyethylene (20) sorbitan monolaurate has good biodegradability and is relatively friendly to the environment. As a non-ionic surfactant, it can also be used as an emulsifier to help the oil-water mixture form a stable emulsion, which is suitable for the preparation of water-based coatings. Therefore, the surfactant in the present invention is most preferably polyoxyethylene (20) sorbitan monolaurate.

[0051] In certain embodiments of the present invention, 5-10% of pigment is added to the bio-based paint for the generator housing. The color of the pigment is selected and adjusted by the user according to the actual application and product requirements, and there is no special restriction.

[0052] The present invention also provides a method for preparing the above-mentioned bio-based coating for the generator housing, comprising the following steps:

[0053] Step S 1 , 40-50% of modified rosin glycerol ester and 12-35% of bio-based solvent are mixed evenly to obtain a mixed solution.

[0054] In certain embodiments of the present invention, the mixing method is preferably stirring, and the stirring conditions are preferably stirring at a speed of 1300-1700 r / min for 7-9 min.

[0055] Step S 2 , disperse the mixed solution and 3-8% filler until a uniform suspension is formed.

[0056] In certain embodiments of the present invention, the dispersion is preferably carried out using a high-speed disperser.

[0057] In certain embodiments of the present invention, when the coating composition of the present invention contains a pigment, preferably 5 to 10% of the pigment is added and dispersed together with 3 to 8% of the filler.

[0058] Step S 3 3. Continue to add 13-25% of modified ricinoleic anhydride and 2-6% of anti-corrosion additive into the suspension and stir evenly to obtain the target coating.

[0059] In certain embodiments of the present invention, the mixing method is preferably stirring, and the stirring conditions are preferably stirring at a speed of 1300-1700 r / min for 7-20 min.

[0060] In certain embodiments of the present invention, the condition for determining whether the mixture is uniformly mixed is until the mixture is completely dissolved as observed by naked eyes.

[0061] In certain embodiments of the present invention, when the coating composition of the present invention contains a rheology modifier, preferably 0.5-2% of the rheology modifier is stirred together with 13-25% of the modified ricinoleic anhydride and 2-6% of the anti-corrosion agent.

[0062] In addition, in order to further adjust the construction viscosity of the bio-based coating for the generator housing to the optimum, the preparation method further comprises the step of adjusting the construction viscosity:

[0063] Step S 4 1. Add 0.1-1% stabilizer to the target coating, and add 0.05-0.5% surfactant in batches;

[0064] The surfactant is added to the target coating at least once, 0.05% each time, until the construction viscosity is adjusted to 60-120 centipoise.

[0065] Specifically, after adding the stabilizer, first add 0.05% surfactant, mix evenly and measure whether the construction viscosity is the set value. If so, stop adding the surfactant to obtain the final required coating. If it does not reach the set value, add 0.05% surfactant again, mix evenly and measure again, and so on, until the measured construction viscosity value is the set value between 60-120 centipoise to obtain the final required coating.

[0066] The present invention also provides a bio-based coating for a generator housing, which is a coating formed by coating and curing the above-mentioned bio-based coating for a generator housing.

[0067] In order to further illustrate the technical solution of the present invention, the preferred embodiments of the present invention are described below in conjunction with examples. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, rather than limiting the claims of the present invention.

[0068] The reagents and materials used in the following examples are all commercially available. Among them, the reagents and materials used in the examples of the present invention are as follows:

[0069] Modified rosin glycerol ester was purchased from Hebei Chuangzhiyuan Biotechnology Co., Ltd., modified castor oil anhydride was purchased from Jinan Shiji Tongda Chemical Co., Ltd., bio-based propylene glycol was purchased from Wuhan Tianzhi Biotechnology Co., Ltd., nano titanium dioxide was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd., zinc phosphate was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd., hydroxyethyl cellulose was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd., ammonium dodecyl sulfate was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd., polyoxyethylene (20) sorbitan monolaurate was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd., and titanium dioxide was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.

[0070] Example 1

[0071] (1) The formula of the bio-based coating for the generator housing provided in this embodiment is as follows:

[0072] The bio-based coating for the generator housing comprises the following components in percentage by weight: 40% of modified rosin glycerol ester, 15% of modified ricinoleic anhydride, 35% of bio-based propylene glycol, 6% of nano titanium dioxide, and 4% of zinc phosphate.

[0073] (2) The preparation method provided in this embodiment has the following steps:

[0074] Step S 1 40% of modified rosin glycerol ester and 35% of bio-based propylene glycol were stirred at a speed of 1500 r / min for 8 minutes to obtain a mixed solution;

[0075] Step S 2 1. After gradually adding 6% nano titanium dioxide into the mixed solution, use a high-speed disperser to disperse it until a uniform suspension is formed;

[0076] Step S 3 3. Continue to add 15% modified ricinoleic anhydride and 4% zinc phosphate into the suspension and stir at a speed of 1500 r / min for 8 minutes to mix evenly.

[0077] (3) In this embodiment, the coating is applied to the generator housing to form a coating process flow:

[0078] a. Surface treatment: Degreasing and phosphating of the newly manufactured generator housing samples;

[0079] b. Roll coating: Use a roller to form a uniform coating with a thickness of 1.0 mm on the surface of the generator housing sample;

[0080] c. Thermal curing: Place at 80°C for 40 hours.

[0081] Example 2

[0082] (1) The formula of the bio-based coating for the generator housing provided in this embodiment is as follows:

[0083] The bio-based coating for the generator shell includes the following ingredients in weight percentage: 48% modified rosin glycerol ester, 16% modified ricinoleic anhydride, 20% bio-based propylene glycol, 3% nano titanium dioxide, 6% zinc phosphate, 1% hydroxyethyl cellulose, 0.5% ammonium lauryl sulfate, 0.5% polyoxyethylene (20) sorbitan monolaurate, and 5% titanium dioxide.

[0084] (2) The preparation method provided in this embodiment has the following steps:

[0085] Step S 1 48% of modified rosin glycerol ester and 20% of bio-based propylene glycol were stirred at a speed of 1500 r / min for 8 minutes to obtain a mixed solution;

[0086] Step S 2 1. After gradually adding 3% nano titanium dioxide and 5% titanium dioxide to the mixed solution, use a high-speed disperser to disperse until a uniform suspension is formed;

[0087] Step S 3 2. Add 16% modified ricinoleic anhydride, 6% zinc phosphate and 1% hydroxyethyl cellulose to the suspension and stir at a speed of 1500 r / min for 8 minutes to mix evenly;

[0088] Step S 4 , continue to add 0.5% ammonium dodecyl sulfate, add 0.05% polyoxyethylene (20) sorbitan monolaurate each time, mix evenly and test the construction viscosity until a total of 0.5% polyoxyethylene (20) sorbitan monolaurate is added to make the construction viscosity 80 centipoise.

[0089] (3) In this embodiment, the coating is applied to the generator housing to form a coating process flow:

[0090] a. Surface treatment: Degreasing and phosphating of the newly manufactured generator housing samples;

[0091] b. Roll coating: Use a roller to form a uniform coating with a thickness of 1.0 mm on the surface of the generator housing sample;

[0092] c. Thermal curing: Place at 80°C for 40 hours.

[0093] Example 3

[0094] The difference between this embodiment and embodiment 2 is that the coating is applied to the generator housing to form a coating, and the curing method is UV curing. The curing conditions are irradiation with 365nm UV light for 2 minutes, and the UV light power is 10mW / cm 2, other parameters are the same.

[0095] Example 4

[0096] The difference between this embodiment and embodiment 2 is that the curing method of applying the coating to the generator housing to form a coating is electron beam curing, the curing condition is irradiation under a 200 keV electron beam for one minute, the electron beam current setting range is 5 to 15 mA, and other parameters are the same.

[0097] Example 5

[0098] (1) The formula of the bio-based coating for the generator housing provided in this embodiment is as follows:

[0099] Modified rosin glycerol ester 50%, modified ricinoleic anhydride 13%, bio-based propylene glycol 20%, nano titanium dioxide 3%, zinc phosphate 6%, hydroxyethyl cellulose 2%, ammonium lauryl sulfate 0.5%, polyoxyethylene (20) sorbitan monolaurate 0.5%, titanium dioxide 5%.

[0100] (2) The preparation method provided in this embodiment has the following steps:

[0101] Step S 1 50% of modified rosin glycerol ester and 20% of bio-based propylene glycol were stirred at a speed of 1500 r / min for 8 minutes to obtain a mixed solution;

[0102] Step S 2 1. After gradually adding 3% nano titanium dioxide and 5% titanium dioxide to the mixed solution, use a high-speed disperser to disperse until a uniform suspension is formed;

[0103] Step S 3 , continue to add 13% modified ricinoleic anhydride, 6% zinc phosphate and 2% hydroxyethyl cellulose to the suspension and stir at a speed of 1500r / min for 8 minutes to mix evenly;

[0104] Step S 4 , continue to add 0.5% ammonium dodecyl sulfate, add 0.05% polyoxyethylene (20) sorbitan monolaurate each time, mix evenly and test the construction viscosity until a total of 0.5% polyoxyethylene (20) sorbitan monolaurate is added to make the construction viscosity 80 centipoise.

[0105] (3) In this embodiment, the coating is applied to the generator housing to form a coating process flow:

[0106] a. Surface treatment: Degreasing and phosphating of the newly manufactured generator housing samples;

[0107] b. Roll coating: Use a roller to form a uniform coating with a thickness of 1.0 mm on the surface of the generator housing sample;

[0108] c. Thermal curing: Place at 80°C for 40 hours.

[0109] Example 6

[0110] The difference between this embodiment and embodiment 5 is that the coating is applied to the generator housing to form a coating, and the curing method is UV curing. The curing conditions are irradiation with 365nm UV light for 2 minutes, and the UV light power is 10mW / cm 2 , other parameters are the same.

[0111] Example 7

[0112] The difference between this embodiment and embodiment 5 is that the curing method of applying the coating to the generator housing to form a coating is electron beam curing, the curing condition is irradiation under a 200 keV electron beam for one minute, the electron beam current setting range is 5 to 15 mA, and other parameters are the same.

[0113] Comparative Example 1

[0114] The coating formula provided in this comparative example is as follows:

[0115] The coating comprises the following components in percentage by weight: 55% of modified rosin glycerol ester, 8% of modified castor oil anhydride, 20% of bio-based propylene glycol, 3% of nano titanium dioxide, 6% of zinc phosphate, 2% of hydroxyethyl cellulose, 0.5% of ammonium lauryl sulfate, 0.5% of polyoxyethylene (20) sorbitan monolaurate and 5% of titanium dioxide.

[0116] (2) The preparation method provided in this comparative example has the following steps:

[0117] Step S 1 55% of modified rosin glycerol ester and 20% of bio-based propylene glycol were stirred at a speed of 1500 r / min for 8 minutes to obtain a mixed solution;

[0118] Step S 2 1. After gradually adding 3% nano titanium dioxide and 5% titanium dioxide to the mixed solution, use a high-speed disperser to disperse until a uniform suspension is formed;

[0119] Step S 3 , continue to add 8% modified ricinoleic anhydride, 6% zinc phosphate and 2% hydroxyethyl cellulose into the suspension and stir at a speed of 1500r / min for 8 minutes to mix evenly;

[0120] Step S 4, continue to add 0.5% ammonium dodecyl sulfate, add 0.05% polyoxyethylene (20) sorbitan monolaurate each time, mix evenly and test the construction viscosity until a total of 0.5% polyoxyethylene (20) sorbitan monolaurate is added to make the construction viscosity 80 centipoise.

[0121] (3) The process flow of applying the coating to the generator housing to form a coating in this comparative example:

[0122] a. Surface treatment: Degreasing and phosphating of the newly manufactured generator housing samples;

[0123] b. Roll coating: Use a roller to form a uniform coating with a thickness of 1.0 mm on the surface of the generator housing sample;

[0124] c. Thermal curing: Place at 80°C for 40 hours.

[0125] The coatings prepared in Examples 1-7 and Comparative Example 1 are marked as Example 1, Example 2, Example 3, Example 4, Example 5, Example 6, Example 7 and Comparative Example 1, respectively. Then, the performances of Examples 1-7 and Comparative Example 1 are tested and compared, and the specific testing methods and test items are as follows:

[0126] (1) Temperature resistance test: Examples 1-7 and Comparative Example 1 were exposed to 130°C and 150°C for 1h for testing. The results are shown in Table 1. The experimental results show that the bio-based coating for the generator housing of a coal-fired unit of the present invention will not crack, fall off or change color significantly at 130°C. The weight loss rate of the coating of Example 1 at 150°C is 3.5%, and the product has good temperature resistance. Example 2 adds auxiliary components such as rheology modifier, stabilizer, surfactant and coating, and the weight ratio of modified rosin glycerol ester and modified castor oil anhydride is the optimal ratio of 3:1. The weight loss rate of the coating at 150°C is only 0.6%, which further improves the temperature resistance of the coating. In Example 5, compared with Example 2, the weight ratio of modified rosin glycerol ester and modified castor oil anhydride is not the optimal ratio of 3:1, and the weight loss rate of the coating at 150°C is 3.1%, indicating that the weight ratio of modified rosin glycerol ester and modified castor oil anhydride will affect the temperature resistance of the coating; although the coating of Comparative Example 1 will not crack, fall off or change color significantly at 130°C, the weight loss rate of the coating at 150°C is as high as 7.6%, and the product has poor temperature resistance. In addition, the excessively high weight loss rate of Comparative Example 1 will lead to waste of coating and increase coating costs.

[0127] Table 1

[0128] 130℃ 150℃ Example 1 No cracking, peeling or significant discoloration Weight loss rate 3.5% Example 2 No cracking, peeling or significant discoloration Weight loss rate 0.6% Example 3 No cracking, peeling or significant discoloration Weight loss rate 0.4% Example 4 No cracking, peeling or significant discoloration Weight loss rate 0.4% Example 5 No cracking, peeling or significant discoloration Weight loss rate 3.1% Example 6 No cracking, peeling or significant discoloration Weight loss rate 1.8% Example 7 No cracking, peeling or significant discoloration Weight loss rate 1.3% Comparative Example 1 No cracking, peeling or significant discoloration Weight loss rate 7.6%

[0129] (2) Wear resistance test: Examples 1-7 and Comparative Example 1 were subjected to pencil scratch test, and the operation process was carried out in accordance with GB / T6739-2006 Determination of film hardness by pencil method for paint and varnish, and the results are shown in Table 2. The experimental results show that the coating made of the bio-based coating for the generator housing of the coal-fired unit of Example 1 can reach a hardness of 7H, and the coating made of the bio-based coating for the generator housing of the coal-fired unit of Example 2 can reach a hardness of 8H. Compared with Example 2, the hardness of the coating made of the bio-based coating for the generator housing of Example 5 is slightly reduced to 7H, indicating that the weight ratio of modified rosin glycerol ester and modified castor oil anhydride has a certain effect on the hardness of the coating. When Example 2 is cured into a coating, the reaction activity is higher and the molecular cross-linking degree is tighter, which further affects the hardness of the coating. The coating hardness of Comparative Example 1 is 6H, and the coating hardness performance is the worst, indicating that the coating cured using the bio-based coating formula for the generator housing of the present invention has excellent wear resistance and compressive strength. In addition, by comparing the hardness results of Examples 2-4 and 5-7, it was found that under the same weight ratio of modified rosin glycerol ester to modified ricinoleic anhydride, different curing methods also have a certain effect on the hardness of the coating, indicating that different curing methods have different reaction activities, so the degree of crosslinking and molecular weight are different. The higher and larger these two indicators are, the stronger the hardness is. In general, electron beam curing method>UV light curing method>thermal curing method.

[0130] Table 2

[0131] hardness Example 1 7H Example 2 8H Example 3 9H Example 4 9H Example 5 7H Example 6 8H Example 7 9H Comparative Example 1 6H

[0132] (3) Standard tape test: Examples 1-7 and Comparative Example 1 were subjected to a standard tape test according to the operating procedures of ASTM D3359. The experimental results showed that a portion of the coatings of Example 1, Examples 3-7 and Comparative Example 1 were torn off, while the coating of Example 2 was not torn off at all and the test was completely passed, indicating that the coating had excellent adhesion strength.

[0133] (4) Corrosion resistance test: Examples 1-7 and Comparative Example 1 were subjected to a neutral salt spray test, and the operation process was referred to "GB / T 6464-2002 Rating of samples and test pieces of metal and other inorganic coatings on metal substrates after corrosion tests". The experimental results show that the protection level Rp of the coating made of bio-based coatings for the generator housing of Examples 1-7 and Comparative Example 1 can reach 10, indicating that the coating has a high ability to protect the generator housing from corrosion and has good salt spray corrosion resistance.

[0134] (5) Electron paramagnetic resonance test:

[0135] Examples 2-7 were subjected to electron paramagnetic resonance testing using a German

[0136] BrukerEMXmicro-6 / 1, the test frequency band is X-band (9.8GHz).

[0137] By the attached Figure 1 As shown, it is a comparison diagram of the free radical intensity of the curing process of Example 2 and Example 5. When the curing method is the same as the thermal curing, the free radical intensity of Example 2 is higher than that of Example 5, indicating that the coating prepared by Example 2 has better mechanical properties. This is because in Example 5, the ratio of modified rosin glycerol ester and modified castor oil anhydride is much greater than 3:1, that is, in the thermal curing reaction process, the carboxyl group (-COOH) provided by the modified castor oil anhydride is insufficient, that is, the cross-linking site is insufficient, and the unsaturated carbon-carbon double bond (C=C) is too much, that is, the free radical source is too much, thus affecting the esterification and cross-linking reaction between the carboxyl group (-COOH) and the unsaturated carbon-carbon double bond (C=C), resulting in low curing efficiency. The 3:1 mass ratio of modified rosin glycerol ester and modified castor oil anhydride can ensure the synergistic effect of the carboxyl group (-COOH) and the unsaturated carbon-carbon double bond (C=C), so that the free radical generation and reaction rate are balanced.

[0138] By the attached Figure 2 As shown, it is a comparison diagram of the free radical intensity of the curing process of Example 3 and Example 6. When both are UV curing methods, Example 3 has a higher free radical intensity than Example 6, indicating that the coating prepared by Example 3 has better mechanical properties. This is because the initiator generates free radicals through light excitation, and these free radicals need to quickly react with double bonds (C=C) to generate active chains. The number of unsaturated carbon-carbon double bonds (C=C) (free radical sources) must match the number of carboxyl groups (-COOH) (cross-linking sites). The 3:1 ratio in the embodiment optimizes the free radical generation and diffusion path, which is the optimal matching ratio, making the curing fast and uniform. In Example 6, the ratio of modified rosin glycerol ester and modified castor oil anhydride is much greater than 3:1, resulting in the number of unsaturated carbon-carbon double bonds (C=C) being much greater than the number of carboxyl groups (-COOH). The imbalance of the cross-linking reaction will make the free radicals more easily lose their activity and reduce the utilization efficiency of the initiator.

[0139] By the attached Figure 3As shown, it is a comparison diagram of the free radical intensity of the curing process of Example 4 and Example 7. When the curing method is the same as electron beam curing, the free radical intensity of Example 4 is higher than that of Example 7, indicating that the coating prepared by Example 4 has better mechanical properties. This is because in electron beam curing, the generation of free radicals depends on the direct action of high-energy electrons on unsaturated carbon-carbon double bonds (C=C), but the free radicals generated by unsaturated carbon-carbon double bonds (C=C) require carboxyl groups (-COOH) to assist crosslinking. When the ratio of modified rosin glycerol ester and modified ricinoleic anhydride in Example 7 is much greater than 3:1, the number of unsaturated carbon-carbon double bonds (C=C) is much greater than the number of carboxyl groups (-COOH), and the free radicals are easily annihilated, resulting in a significant decrease in curing efficiency. The imbalance of the crosslinking reaction will make the free radicals more likely to lose activity and annihilate, reducing the utilization efficiency of the initiator.

[0140] Therefore, when the mass ratio of modified rosin glycerol ester and modified castor oil anhydride is the optimal ratio of 3:1, the number of carboxyl groups and the number of carbon-carbon double bonds are in stoichiometric balance. After each free radical is generated, there are enough carboxyl groups to participate in crosslinking, which reduces the annihilation of free radicals and improves the conversion rate of double bonds. The presence of an appropriate number of carboxyl groups promotes the diffusion and reaction of free radicals, and the rates of free radical generation and curing network formation are more matched, making the curing network more uniformly formed. When the mass ratio of modified rosin glycerol ester and modified castor oil anhydride is greater than 3:1, the number of carboxyl groups provided by modified castor oil anhydride is too small, which directly affects the generation and stable diffusion of free radicals, because carboxyl groups are both reaction sites and free radical stabilizing additives. At this time, the free radical reaction sites are insufficient and cannot fully react. The excessively high ratio of carbon-carbon double bonds makes it easier for free radicals to directly combine with each other (such as two free radicals react to generate inactive molecules), resulting in a decrease in the total amount of free radicals and an enhanced annihilation effect. In addition, the crosslinking network density is insufficient, the curing efficiency is reduced, and the overall free radical concentration and curing efficiency are inhibited.

[0141] By the attached Figure 4As shown, it is a comparison chart of the free radical intensity of the curing process under different curing methods of Examples 2-4 (i.e., the mass ratio of modified rosin glycerol ester and modified castor oil anhydride is the optimal ratio of 3:1). It can be seen that the bio-based coating provided by the present invention can undergo chemical reactions under different curing methods such as electron beam curing, ultraviolet light curing and thermal curing to form a coating, and the free radical intensity of different curing methods is different. Among them, the free radical intensity of Example 4 is higher and the curing reaction time is shorter, indicating that the electron beam curing coating is faster and has better mechanical properties, which is suitable for the rapid construction of thick coatings or complex-shaped generators; compared with Example 3 and Example 4, the free radical intensity has decreased to a certain extent and the reaction time has been extended in the ultraviolet light curing method; and compared with Example 2 and Example 3 and Example 4, the free radical intensity has decreased significantly in the thermal curing method, and the reaction time has been extended to about ten hours, and the mechanical properties have decreased compared with Example 3 and Example 4.

[0142] In summary, the bio-based coating for the generator casing prepared by the present invention supports the selection of a variety of curing methods to form a coating, which effectively improves the construction efficiency. Users can choose the corresponding curing method according to their own construction conditions. It has strong versatility and flexibility. In addition, the formed coating has good temperature resistance, wear resistance, corrosion resistance and environmental protection, and has excellent comprehensive performance, which can meet the protection needs of the surface of large generators of coal-fired units.

[0143] The above-mentioned embodiments are only preferred embodiments of the present invention and cannot be used to limit the scope of protection of the present invention. Any non-substantial changes and substitutions made by technicians in this field on the basis of the present invention shall fall within the scope of protection required by the present invention.

Claims

1. A bio-based coating for a generator housing, characterized in that: The invention comprises the following components in weight percentage: 40-50% of modified rosin glycerol ester, 13-25% of modified ricinoleic anhydride, 12-35% of bio-based solvent, 3-8% of filler, and 2-6% of anti-corrosion additive; Used to form coatings under any of the curing methods: thermal curing, UV curing, and electron beam curing.

2. The bio-based coating for a generator housing according to claim 1, characterized in that: The weight ratio of the modified rosin glycerol ester to the modified ricinoleic anhydride is 3:

1.

3. The bio-based coating for a generator housing according to claim 1, characterized in that: The particle size of the filler is 20-100 nm.

4. The bio-based coating for a generator housing according to claim 1, characterized in that: The bio-based solvent is any one or a combination of bio-based propylene glycol, bio-based butylene glycol and bio-based glycerol; and / or The filler is any one or a combination of nano titanium dioxide, nano silicon dioxide and nano zirconium dioxide; and / or The anti-corrosion additive is any one or a combination of zinc phosphate, zinc molybdate and zinc tungstate.

5. The bio-based coating for a generator housing according to claim 1, characterized in that: It also includes 0.5-2% of a rheology modifier, wherein the rheology modifier is hydroxyethyl cellulose; and / or It also includes 0.1-1% of a stabilizer, wherein the stabilizer is any one or a combination of ammonium dodecyl sulfate, propylene glycol alginate and bis(1,2,2,6,6-pentylmethyl-4-piperidinyl) sebacate; and / or It also includes 0.05-0.5% of a surfactant, wherein the surfactant is any one or a combination of polyoxyethylene (20) sorbitan monolaurate and fatty alcohol polyoxyethylene ether; and / or It also contains 5-10% pigment.

6. A method for preparing a bio-based coating for a generator housing, characterized in that: The preparation method is used to prepare the bio-based coating for the generator housing according to any one of claims 1 to 5, comprising the following steps: Step S1, mixing 40-50% of modified rosin glycerol ester and 12-35% of bio-based solvent to obtain a mixed solution; Step S2, dispersing the mixed solution and 3-8% of filler to form a suspension; Step S3, adding 13-25% of modified ricinoleic anhydride and 2-6% of anti-corrosion additive to the suspension to obtain the target coating.

7. The preparation method according to claim 6, characterized in that: The method further comprises the step of adjusting the construction viscosity: Step S4, adding 0.1-1% of a stabilizer to the target coating, and adding 0.05-0.5% of a surfactant in portions; The surfactant is added to the target coating at least once, 0.05% each time, until the construction viscosity is adjusted to 60-120 centipoise.

8. The preparation method according to claim 6, characterized in that: 5-10% of the pigment is added in step S2 together with 3-8% of the filler; and / or 0.5-2% of the rheology modifier is added in step S3 together with 13-25% of the modified ricinoleic anhydride and 2-6% of the anti-corrosion aid.

9. A bio-based coating for a generator housing, characterized in that: The coating is formed by applying and curing the bio-based coating for the generator housing; the bio-based coating for the generator housing is the bio-based coating for the generator housing according to any one of claims 1-5.

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