Triazine ring group epoxy resin, modified epoxy resin and preparation method and application thereof

Abstract

The invention provides triazine ring-based epoxy resin, modified epoxy resin and a preparation method and application of the triazine ring-based epoxy resin. The preparation method of the triazine ring-based epoxy resin comprises the steps that a first mixed reaction system containing a triazine ring substance and a chain extender is subjected to a first reaction, a triazine ring adduct is prepared, and the chain extender comprises at least one of an alcohol chain extender, an acid chain extender and an aldehyde chain extender; and carrying out a second reaction on a second mixed reaction system containing the triazine cycloadduct, epoxy chloropropane and hydroxide to prepare the triazine ring-based epoxy resin. According to the invention, the triazine ring-containing substance and the chain extender are subjected to a chain extension reaction, so that on one hand, the content of the triazine ring can be increased, and the hardness and corrosion resistance of the coating can be adjusted through the plane structure of the triazine ring; on the other hand, the hydroxyl functionality can be increased, and the strength and flexibility of the triazine cycloadduct can be adjusted. The prepared triazine ring-based epoxy resin has excellent weather resistance and salt spray resistance.

Description

Technical Field

[0001] This invention belongs to the field of epoxy resin technology, specifically relating to a triazine cyclic epoxy resin, a modified epoxy resin, its preparation method, and its application. Background Technology

[0002] Epoxy resins are thermosetting polymers containing two or more epoxy groups in their molecular chains. These epoxy groups typically exhibit a three-membered epoxy ring structure, consisting of one oxygen atom and two adjacent carbon atoms. Due to the inherent ring strain of the three-membered ring, this functional group possesses extremely high chemical reactivity, allowing it to undergo cross-linking polymerization reactions with various types of curing agents, including amines, acid anhydrides, phenols, and thiols. Through ring-opening and chain growth of the epoxy groups, a three-dimensional network cross-linked structure is ultimately formed in the cured product. Cured epoxy resins exhibit excellent comprehensive properties, such as superior mechanical properties, corrosion resistance, chemical resistance, and electrical insulation, while also possessing good dimensional stability and processability. Based on these performance advantages, epoxy resins are widely used in high-performance structural adhesives, heavy-duty anti-corrosion coatings, advanced composite material matrices, electronic device packaging materials, and electrical insulation materials.

[0003] However, bisphenol A epoxy resins, which are widely used in industry, have the following performance shortcomings: their main and side chain structures contain a large number of rigid benzene ring units. These units are prone to photo-oxidative degradation under ultraviolet (UV) irradiation. Specifically, the conjugated structure of the benzene rings is destroyed, the molecular chains break, and small oxygen-containing degradation products are generated. This leads to severe chalking, loss of gloss, and discoloration on the material surface, and a sharp decline in key properties such as mechanical strength and adhesion. These photo-aging failure problems significantly limit the application of bisphenol A epoxy resins in outdoor exposed environments (such as building exterior wall coatings, outdoor composite material components, and outdoor electrical equipment insulation components).

[0004] To address the technical problem of insufficient weather resistance in epoxy resins, researchers typically start with the molecular structure design of the epoxy resin itself and the curing agent, developing alicyclic epoxy resins and matching alicyclic curing agents with excellent weather resistance and heat resistance. For example, existing technology CN104193961A discloses a hydrogenated bisphenol A type epoxy resin prepared using hydrogenated bisphenol A and epichlorohydrin as core raw materials under the action of a Lewis acid catalyst. The synthesis of the key intermediate, hydrogenated bisphenol A, requires specific reaction conditions: a benzene ring catalytic hydrogenation reaction must be carried out under high temperature and high pressure conditions of 80-150℃ and 3-10MPa, and noble metal catalysts such as Pd / C and Rh / Al2O3 must be used. This process results in a synthesis cost 40%-80% higher than that of traditional bisphenol A type epoxy resins, indicating a significant problem of high production costs. Existing technology CN103756610A discloses a two-component yellowing-resistant epoxy adhesive. However, its two-component system involves complex raw material compatibility and cumbersome preparation processes, ultimately resulting in high overall product costs and hindering low-cost large-scale production. Existing technology CN114524785A uses cyclohexene-methanol and 1,6-dibromohexane as raw materials, undergoing a substitution reaction to obtain 1,6-bis(cyclohex-3-en-1-ylmethoxy)hexane, which then undergoes a cyclization reaction with dichloroethane. Although this monomer possesses advantages such as high purity and high thermal stability, this type of alicyclic epoxy resin exhibits significant reactivity defects. Its reactivity with amine curing agents is low, making it difficult to complete effective crosslinking reactions at room temperature. Additional temperature control or the addition of specific accelerators is required, increasing the complexity of the application process. Summary of the Invention

[0005] To solve all or part of the above-mentioned technical problems, the present invention provides the following technical solutions: A first aspect of the present invention provides a method for preparing a triazine cyclic epoxy resin, comprising: A first reaction is carried out in a first mixed reaction system containing a triazine ring substance and a first chain extender to obtain a triazine cycloadduct, wherein the first chain extender includes at least one of alcohol chain extenders, acid chain extenders, and aldehyde chain extenders; A second reaction is carried out on a second mixed reaction system containing the triazine cycloaddition compound, epichlorohydrin, and hydroxide to obtain a triazine cyclo-based epoxy resin.

[0006] The preparation method provided by this invention first involves reacting a triazine ring-containing substance with a first chain extender. This increases the triazine ring content, allowing the planar structure of the triazine ring to adjust the hardness and corrosion resistance of the coating. It also increases the hydroxyl functionality, adjusting the strength and flexibility of the triazine ring adduct. Then, it reacts with epichlorohydrin to introduce epoxy groups. The resulting triazine ring-based epoxy resin exhibits improved weather resistance and salt spray resistance compared to existing bisphenol A type epoxy resins.

[0007] In some embodiments, the temperature of the first reaction is 60°C to 200°C, or it can be 60°C to 190°C.

[0008] In some embodiments, the first reaction takes 1 to 10 hours.

[0009] In some embodiments, the mass ratio of the triazine ring substance to the first chain extender in the first mixed reaction system is 10~80:1~50.

[0010] In some embodiments, the temperature of the second reaction is 30°C to 100°C, and can be 50°C to 100°C.

[0011] In some embodiments, the second reaction takes 1 to 10 hours.

[0012] In some embodiments, the amount of epichlorohydrin used satisfies the following condition: the molar ratio of the alcohol hydroxyl group in the triazine cycloadduct to epichlorohydrin is 0.3~0.5:0.4~0.6. Alternatively, the amount of epichlorohydrin added can be 1~1.3 times the molar number of hydroxyl groups in the triazine cycloadduct.

[0013] In some embodiments, the amount of hydroxide added satisfies the following condition: the molar ratio of the alcohol hydroxyl group in the triazine cycloaddition to the hydroxide is 0.3~0.5:0.5~0.7.

[0014] In some embodiments, the triazine-containing substance includes one or more of the following: triazine A resin, melamine, methylated melamine-formaldehyde resin, butylated melamine-formaldehyde resin, 1,2,3-triazine, 1,3,5-homogeneous triazine, 1,2,4-triazine, cyanuryl chloride, cyanuryl bromide, and triglycidyl isocyanurate, but is not limited thereto.

[0015] In some embodiments, the alcohol chain extender includes one or more of ethylene glycol, glycidol, neopentyl glycol, and trimethylpentyl glycol.

[0016] In some embodiments, the acid chain extender includes one or more of neodecanoic acid, acetic acid, propionic acid, butyric acid, dodecanoic acid, stearic acid, and soybean oil fatty acids.

[0017] In some embodiments, the aldehyde chain extender includes one or a combination of formaldehyde, paraformaldehyde, glyoxal, and glutaraldehyde.

[0018] If melamine is chosen as the triazine ring-containing substance, then aldehyde chain extenders and / or alcohol chain extenders, such as formaldehyde, glyoxal, and ethylene glycol, can be selected. If triglycidyl isocyanurate is chosen as the triazine ring-containing substance, then acid chain extenders can be selected to convert epoxy groups into hydroxyl groups.

[0019] In some embodiments, the first mixed reaction system and / or the second mixed reaction system further include a catalyst, wherein the mass ratio of the triazine ring-containing substance to the catalyst is 10~80:0.1~5.

[0020] In some embodiments, the catalyst includes one or more of the following: boron trifluoride ether, tin chloride, phosphoric acid, sulfuric acid, potassium persulfate, amine persulfate, triphenylphosphine, benzoic acid, and p-toluenesulfonic acid.

[0021] In some embodiments, the second reaction specifically includes: reacting the triazine cycloaddition with epichlorohydrin at 30°C to 100°C for 1 to 5 hours, then adding hydroxide and continuing the reaction at 30°C to 100°C for another 1 to 5 hours, thereby obtaining a triazine cyclo-based epoxy resin. The addition of hydroxide is used to remove chlorine atoms to form epoxy groups.

[0022] In some embodiments, the hydroxide includes one or a combination of sodium hydroxide and calcium hydroxide. For example, it can be prepared as an aqueous solution of hydroxide for use.

[0023] In some embodiments, the amount of hydroxide added satisfies the following condition: the molar ratio of the alcohol hydroxyl group in the triazine cycloaddition to the hydroxide is 0.3~0.5:0.5~0.7.

[0024] For example, the preparation method of the triazine cyclic epoxy resin specifically includes: S1: Mix 10-80 parts by mass of a triazine ring-containing substance, 1-50 parts by mass of a first chain extender, and 0-5 parts by mass of a catalyst (optional), and heat to 60℃-190℃ under stirring for 1-10 hours to obtain a triazine cycloadduct. S2: Add 0.1-3 parts by mass of catalyst to the reaction product of step S1, mix and stir until dissolved, then add epichlorohydrin, react at 50-100°C for 1-5 hours, then add sodium hydroxide aqueous solution, react at 50-100°C for 1-5 hours, wash with water until neutral, dehydrate to obtain triazine cyclo-based epoxy resin.

[0025] A solvent can also be added during the above reaction process. The solvent can be any one or a combination of xylene, benzene, toluene, trimethylbenzene, ethylene glycol, propylene glycol, and butanediol. The amount of solvent used can be, for example, 0-50 parts by mass. The solvent's main function is extraction and purification, and it can be recovered and reused.

[0026] A second aspect of the present invention provides another method for preparing a triazine cyclic epoxy resin, comprising: subjecting a third mixed reaction system having a triazine cyclic substance and a second chain extender to a third reaction; wherein the triazine cyclic substance comprises one or a combination of melamine, methylated melamine-formaldehyde resin, and butylated melamine-formaldehyde resin, and the second chain extender comprises glycidol, thereby obtaining a triazine cyclic epoxy resin.

[0027] In some embodiments, the reaction temperature of the third reaction is 140°C to 180°C.

[0028] In some embodiments, the reaction temperature of the third reaction is 1~10h.

[0029] In some embodiments, the mass ratio of the triazine ring substance to the second chain extender in the third mixed reaction system is 10~80:1~50.

[0030] In some embodiments, the second chain extender may further include one or more of other alcohol chain extenders and aldehyde chain extenders. Other alcohol chain extenders include one or more of ethylene glycol, neopentyl glycol, and trimethylpentyl glycol; aldehyde chain extenders include one or more of formaldehyde, paraformaldehyde, glyoxal, and glutaraldehyde. In embodiments where other second chain extenders besides glycidol are included, the mass percentage of glycidol may be 60% or more of the second chain extender.

[0031] In some embodiments, the third mixed reaction system may further include a catalyst, wherein the mass ratio of the triazine ring-containing substance to the catalyst is 10-80:0.1-5. The catalyst may, for example, include one or a combination of boron trifluoride diethyl ether, tin chloride, phosphoric acid, sulfuric acid, potassium persulfate, amine persulfate, triphenylphosphine, benzoic acid, and p-toluenesulfonic acid.

[0032] In some embodiments, the third mixed reaction system may further include a solvent, such as any one or a combination of xylene, benzene, toluene, trimethylbenzene, ethylene glycol, propylene glycol, and butanediol.

[0033] A third aspect of the present invention provides a triazine cyclic epoxy resin, which is prepared by the method for preparing triazine cyclic epoxy resin as described in any of the technical solutions.

[0034] A fourth aspect of the present invention provides a method for preparing a modified epoxy resin, comprising: Triazine cycloalkyl epoxy resin is prepared by any of the preparation methods of triazine cycloalkyl epoxy resin described in any of the technical solutions; A fourth reaction is carried out in the fourth mixed reaction system containing the triazine cyclic epoxy resin and the organic ultraviolet absorber, so that the triazine cyclic epoxy resin is grafted with the organic ultraviolet absorber through epoxy groups to obtain a modified epoxy resin.

[0035] By utilizing the chemical reaction between the epoxy groups in triazine cyclic epoxy resin and organic ultraviolet absorbers to graft ultraviolet absorbers, the weather resistance of the resulting modified epoxy resin is further improved.

[0036] In some embodiments, the temperature of the fourth reaction is 60°C to 120°C.

[0037] In some embodiments, the fourth reaction takes 1 to 5 hours.

[0038] In some embodiments, the mass ratio of the triazine ring-containing substance to the organic ultraviolet absorber is 10~80:1~5.

[0039] In some embodiments, the organic ultraviolet absorber includes one or more combinations of 2-(2-hydroxy-5-benzyl)benzotriazole, benzotriazole, salicylates (such as salicylic acid), benzophenones, and substituted acrylonitrile.

[0040] For example, the preparation method of the modified epoxy resin specifically includes: S1: Mix 10-80 parts by mass of a triazine ring-containing substance, 1-50 parts by mass of a first chain extender, and 0-5 parts by mass of a catalyst (optional), and heat to 60-190°C under stirring for 1-10 hours to obtain a triazine cycloadduct. S2: Add 0.1-3 parts by mass of catalyst to the reaction product of step S1, mix and stir until dissolved, then add epichlorohydrin, react at 50-100°C for 1-5 hours, then add sodium hydroxide aqueous solution, react at 50-100°C for 1-5 hours, wash with water until neutral, dehydrate to obtain triazine cyclo-epoxy resin. S3: The triazine cyclic epoxy resin obtained in step S2 is mixed with 1-5 parts by weight of an organic ultraviolet absorber and reacted at 60-120°C for 1-5 h to obtain the modified epoxy resin.

[0041] The fifth aspect of the present invention provides a modified epoxy resin, which is prepared by the method for preparing the modified epoxy resin described in any of the technical solutions.

[0042] A sixth aspect of the present invention provides a coating comprising the triazine cycloalcoholic epoxy resin described in any one of the technical solutions and / or the modified epoxy resin described in any one of the technical solutions.

[0043] The coating may be, for example, an anti-corrosion coating. The coating formulation may be any epoxy resin-based coating formulation known in the art; for example, the epoxy resin in any known coating formulation may be replaced with the triazine cyclic epoxy resin and / or modified epoxy resin of the present invention to obtain the coating described in the present invention.

[0044] A sixth aspect of the invention provides a coating comprising a cured product of the coating.

[0045] Compared with the prior art, the present invention includes some or all of the following beneficial effects: (1) The preparation method provided by the present invention first involves reacting a triazine ring-containing substance with a chain extender to increase the triazine ring content, thereby adjusting the hardness and corrosion resistance of the coating through the planar structure of the triazine ring; on the other hand, it increases the hydroxyl functionality to adjust the strength and flexibility of the triazine ring adduct; then, it reacts with epichlorohydrin to introduce epoxy groups. The triazine ring-based epoxy resin obtained in this way has improved weather resistance and salt spray resistance compared with the existing bisphenol A type epoxy resin.

[0046] (2) The present invention utilizes the chemical reaction between the epoxy groups in the triazine cyclic epoxy resin and the organic ultraviolet absorber to graft the ultraviolet absorber, thereby further improving the weather resistance of the modified epoxy resin. Attached Figure Description

[0047] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0048] In the infrared spectrum, characteristic absorption peaks of the amino group were observed at 3441 cm⁻¹ and near 1700 cm⁻¹, the stretching vibration absorption peak of the methylene group was observed near 3000 cm⁻¹, the carbonyl group absorption peak was observed at 1700 cm⁻¹, and the triazine ring skeletal vibration peaks were observed at 1300, 1500, and 1600 cm⁻¹. The NMR spectrum indicated that the peak at 3.34–3.36 cm⁻¹ was the proton peak of the methylene group connected to -NH.

[0049] Figure 1 This is the infrared spectrum of the epoxy resin prepared in Example 3-1 of this invention; Figure 2 This is the nuclear magnetic resonance spectrum of the epoxy resin prepared in Example 3-1 of this invention. Detailed Implementation

[0050] The invention will be more fully understood through the following detailed description, which should be read in conjunction with the accompanying drawings. Detailed embodiments of the invention are disclosed herein; however, it should be understood that the disclosed embodiments are merely exemplary of the invention, which may be embodied in various forms. Therefore, the specific functional details disclosed herein should not be construed as limiting, but rather as the basis for the claims and as intended to teach those skilled in the art to employ the representative basis of the invention in different ways in any suitable detailed embodiment.

[0051] In addition, unless otherwise specified, all raw materials used in the following embodiments can be purchased from the market or other sources, and all production and testing equipment used are known in the art, as are the testing methods used.

[0052] Unless otherwise specified, in the following specific embodiments of the present invention, the "parts" of raw material usage refers to parts by mass, and the "%" of raw material concentration refers to a percentage by mass.

[0053] Example 1-1 This embodiment provides a triazine cyclic epoxy resin and its preparation method, the reaction process of which is shown below: The preparation method specifically includes the following steps: 10 parts of melamine, 15 parts of paraformaldehyde (paraformaldehyde decomposes into formaldehyde under high temperature conditions), and 45 parts of ethylene glycol were added to a reaction vessel. The mixture was heated to 50°C and held for 2 hours with stirring, then heated to 150°C and held for 1 hour. Unreacted ethylene glycol was removed under vacuum. After the reaction was completed, a triazine cycloaddition was obtained. Then, 0.5 parts of boron trifluoride ether were added and stirred until dissolved. 35 parts of epichlorohydrin were added to the solution and reacted at 100°C for 2 hours. Then, 38 parts of 40wt% sodium hydroxide aqueous solution were added and reacted at 80°C for 3 hours. The mixture was washed with water until neutral and dehydrated to obtain a triazine cyclo-based epoxy resin.

[0054] Examples 1-2 Examples 1-2 provide a modified epoxy resin and its preparation method, which differ from Examples 1-1 only in that: In Examples 1-2, after obtaining the triazine cyclic epoxy resin, 5 parts of benzotriazole were added to the reaction product containing the triazine cyclic epoxy resin, and the mixture was reacted at 80°C for 1 hour to obtain a modified epoxy resin with high weather resistance. The rest of the process was the same as in Example 1-1, and will not be repeated here.

[0055] Example 2-1 This embodiment provides a triazine cyclic epoxy resin and its preparation method, specifically including the following steps: 80 parts of butylated melamine-formaldehyde resin, 24 parts of ethylene glycol, and 1 part of phosphoric acid were added to a reaction vessel. The mixture was heated to 190°C with stirring and reacted for 3 hours. After evacuation for 1 hour, a triazine cycloaddition was obtained. The mixture was then cooled to 50°C, and 0.2 parts of 47wt% boron trifluoride ether were added. The mixture was stirred until dissolved, and 45 parts of epichlorohydrin were added to the solution. The mixture was reacted at 50°C for 1 hour. Excess epichlorohydrin was removed under vacuum, and 40 parts of 40wt% sodium hydroxide aqueous solution were added. The mixture was reacted at 50°C for 2 hours, washed with water until neutral, and dehydrated to obtain a triazine cyclo-based epoxy resin.

[0056] Example 2-2 Example 2-2 provides a modified epoxy resin and its preparation method, which differs from Example 2-1 only in that: In Example 2-2, after obtaining the triazine cyclic epoxy resin, 1 part of benzotriazole was added to the reaction product containing the triazine cyclic epoxy resin, and the mixture was reacted at 60°C for 1 hour to obtain the modified epoxy resin. The rest of the process was the same as in Example 2-1, and will not be repeated here.

[0057] Example 3-1 This embodiment provides a triazine cyclic epoxy resin and its preparation method, specifically including the following steps: 39 parts of triglycidyl isocyanurate and 30 parts of lauric acid were added to a reaction vessel and heated to 120°C under stirring until the acid value of the reactant was ≤3. The reaction was then stopped to obtain a triazine cycloaddition. The temperature was then lowered to 60°C and 0.5 parts of tin chloride were added. The mixture was stirred until dissolved and 14 parts of epichlorohydrin were added to the solution. The reaction was carried out at 90°C for 3 hours. Then, 15 parts of a 40wt% sodium hydroxide aqueous solution were added and the reaction was carried out at 100°C for 5 hours. The mixture was washed with water until neutral and dehydrated to obtain a triazine cyclo-based epoxy resin.

[0058] Example 3-2 Example 3-2 provides a modified epoxy resin and its preparation method, which differs from Example 3-1 only in that: In Example 3-2, after obtaining the triazine cyclic epoxy resin, 1 part of 2-(2-hydroxy-5-benzyl)benzotriazole was added to the reaction product containing the triazine cyclic epoxy resin, and the mixture was reacted at 80°C for 2 hours to obtain the modified epoxy resin. The rest of the process was the same as in Example 3-1, and will not be repeated here.

[0059] Example 4 This embodiment provides a method for preparing modified epoxy resin, specifically including: adding 50 parts of methylated melamine-formaldehyde resin, 45 parts of glycidol, and 0.5 parts of p-toluenesulfonic acid to a reaction vessel, heating to 180°C while stirring, removing 20 parts of methanol, and then cooling to obtain triazine cycloalkyl epoxy resin; then adding 5 parts of xylene and 1 part of salicylic acid, and reacting at 120°C for 2 hours to obtain modified epoxy resin.

[0060] Example 5 10 parts of melamine, 38 parts of glutaraldehyde aqueous solution (glutaraldehyde concentration of 40wt%) and 30 parts of glycidol were added to a reaction vessel, heated to 100°C under stirring, and kept at that temperature for 5 hours. Excess water was removed under vacuum to obtain triazine cyclo-based epoxy resin. Then, 2 parts of salicylic acid were added and reacted at 120°C for 1 hour to obtain modified epoxy resin.

[0061] Comparative Example 1 The only difference between Comparative Example 1 and Example 1-1 is that melamine is not used in Comparative Example 1. The rest of the implementation is the same as in Example 1-1, and will not be repeated here.

[0062] Comparative Example 2 The only difference between Comparative Example 2 and Example 1-1 is that Comparative Example 2 does not use paraformaldehyde. The rest of the procedures are the same as those in Example 1-1, and will not be repeated here.

[0063] Comparative Example 3 The only difference between Comparative Example 3 and Example 1-1 is that Comparative Example 3 does not use ethylene glycol. The rest of the implementation is the same as that of Example 1-1, and will not be repeated here.

[0064] Comparative Example 4 The only difference between Comparative Example 4 and Examples 1-1 is that Comparative Example 4 does not use boron trifluoride ether. The rest of the procedures are the same as those in Examples 1-1, and will not be repeated here.

[0065] Comparative Example 5 Commercially available epoxy resin E51.

[0066] Comparative Example 6 Commercially available acrylic resin, purchased from Jiangsu Sanmu Chemical Co., Ltd.

[0067] Figure 1 This is the infrared spectrum of the epoxy resin prepared in Example 3-1 of this invention; Figure 2 This is the nuclear magnetic resonance spectrum of the epoxy resin prepared in Example 3-1 of this invention. Figure 1 In the infrared spectrum shown, a region located at 3441 cm⁻¹ was observed. -1 1700cm -1 The area near the characteristic absorption peak of amino groups is 3000 cm⁻¹. -1The nearby peak is the stretching absorption vibration absorption peak of the methylene group, at 1700 cm⁻¹. -1 It is the absorption peak of the carbonyl group, and 1300 cm⁻¹ is the peak value of the carbonyl group -1 1500cm -1 1600cm -1 It is a triazine ring skeletal vibration peak. Figure 2 The NMR spectrum shown indicates that the peak at 3.34–3.36 is a methylene proton peak connected to -NH.

[0068] Anti-rust coatings were prepared using the triazine cyclic epoxy resin, modified epoxy resin, and commercially available epoxy resin obtained in the above examples. The coating formulations are shown in Table 1. Table 1. Formulation of epoxy resin anti-rust coating A rust-preventive coating, made from triazine cyclic epoxy resin, modified epoxy resin, and commercially available epoxy resin, is applied to a carbon steel plate to form a dried rust-preventive coating with a thickness of approximately 100 μm.

[0069] Under the same conditions, the above-mentioned anti-rust coatings and anti-rust coatings were subjected to relevant performance tests. The relevant performance test methods are shown in Table 2.

[0070] Table 2 Test methods for relevant performance of anti-rust coatings Table 3. Relevant properties of epoxy resin anti-rust coatings and anti-rust coatings based on the above embodiments and comparative examples. As can be seen from Table 3, the anti-rust coatings of triazine cyclic epoxy resin and UV absorber-modified epoxy resin prepared by the embodiments of the present invention have better aging resistance and salt spray resistance than the comparative examples. Moreover, the directional coatings obtained have excellent workability, with fast drying speed, high viscosity, good flexibility and good adhesion, and obvious comprehensive performance advantages.

[0071] Comparing the three groups of Examples 1-1 and 1-2, 2-1 and 2-2, and 3-1 and 3-2 respectively, it was found that the modified epoxy resin obtained by further modification with ultraviolet absorber has better aging resistance and is therefore the preferred solution.

[0072] In addition, the inventors of this case also conducted experiments with other raw materials, process operations, and process conditions described in this specification, referring to the aforementioned embodiments, and obtained relatively ideal results in all cases.

[0073] All aspects, embodiments, features, and examples of this invention should be considered illustrative and used to explain and illustrate the invention, but not to limit the invention. The scope of the invention is defined only by the claims.

[0074] Although the invention has been described with reference to illustrative embodiments, those skilled in the art will understand that various other changes, omissions, and / or additions can be made without departing from the spirit and scope of the invention, and that elements of the described embodiments can be substituted with substantially equivalents. Furthermore, many modifications can be made without departing from the scope of the invention to adapt particular situations or materials to the teachings of the invention. Therefore, this invention is not intended to be limited to the specific embodiments disclosed for carrying out the invention, but rather is intended to encompass all embodiments falling within the scope of the appended claims.

Claims

1. A method for preparing a triazine cyclic epoxy resin, characterized in that, include: A first reaction is carried out in a first mixed reaction system containing a triazine ring substance and a first chain extender to obtain a triazine cycloadduct, wherein the first chain extender includes at least one of alcohol chain extenders, acid chain extenders, and aldehyde chain extenders; A second reaction is carried out on a second mixed reaction system containing the triazine cycloaddition compound, epichlorohydrin, and hydroxide to obtain a triazine cyclo-based epoxy resin.

2. The method for preparing the triazine cyclic epoxy resin according to claim 1, characterized in that: The temperature of the first reaction is 60℃~200℃, and / or the time of the first reaction is 1~10h; And / or, the mass ratio of the triazine ring substance to the first chain extender in the first mixed reaction system is 10~80:1~50; And / or, the temperature of the second reaction is 30℃~100℃, and / or, the time of the second reaction is 1~10h; And / or, the molar ratio of the alcohol hydroxyl group to epichlorohydrin in the triazine cycloaddition is 0.3~0.5:0.4~0.6; And / or, the amount of hydroxide added satisfies the following condition: the molar ratio of the alcohol hydroxyl group to the hydroxide in the triazine cycloaddition is 0.3~0.5:0.5~0.7; And / or, the triazine ring-containing substance includes one or more of the following: triazine A resin, melamine, methylated melamine-formaldehyde resin, butylated melamine-formaldehyde resin, 1,2,3-triazine, 1,3,5-homogeneous triazine, 1,2,4-triazine, cyanuryl chloride, cyanuryl bromide, and triglycidyl isocyanurate; And / or, the alcohol chain extender includes one or more of ethylene glycol, glycidol, neopentyl glycol, and trimethylpentyl glycol; and / or, the acid chain extender includes one or more of neodecanoic acid, acetic acid, propionic acid, butyric acid, lauric acid, stearic acid, and soybean oil fatty acids; and / or, the aldehyde chain extender includes one or more of formaldehyde, paraformaldehyde, glyoxal, and glutaraldehyde.

3. The method for preparing the triazine cyclic epoxy resin according to claim 1 or 2, characterized in that: The first mixed reaction system and / or the second mixed reaction system further include a catalyst, wherein the mass ratio of the triazine ring-containing substance to the catalyst is 10~80:0.1~5; preferably, the catalyst includes one or more of boron trifluoride diethyl ether, tin chloride, phosphoric acid, sulfuric acid, potassium persulfate, amine persulfate, triphenylphosphine, benzoic acid, and p-toluenesulfonic acid. And / or, the second reaction specifically includes: reacting the triazine cycloaddition with epichlorohydrin at 30°C to 100°C for 1 to 5 hours, and then adding the hydroxide and continuing the reaction at 30°C to 100°C for 1 to 5 hours, thereby obtaining a triazine cyclo-based epoxy resin.

4. A method for preparing a triazine cyclic epoxy resin, characterized in that, include: A third reaction is carried out in a third mixed reaction system containing a triazine ring substance and a second chain extender; the triazine ring substance includes one or more of melamine, methylated melamine-formaldehyde resin, and butylated melamine-formaldehyde resin, and the second chain extender includes glycidol, to obtain a triazine cyclic epoxy resin.

5. The preparation method according to claim 4, characterized in that: The reaction temperature of the third reaction is 140℃~180℃, and / or the reaction time is 1~10h; And / or, the mass ratio of the triazine ring substance to the second chain extender in the third mixed reaction system is 10~80:1~50; And / or, the third mixed reaction system further includes a catalyst, wherein the mass ratio of the triazine ring-containing substance to the catalyst is 10~80:0.1~5; preferably, the catalyst includes one or more of boron trifluoride diethyl ether, tin chloride, phosphoric acid, sulfuric acid, potassium persulfate, amine persulfate, triphenylphosphine, benzoic acid, and p-toluenesulfonic acid.

6. A triazine cyclic epoxy resin, characterized in that, It is prepared by the method of any one of claims 1 to 5.

7. A method for preparing a modified epoxy resin, characterized in that, include: Triazine cyclic epoxy resin was prepared by the preparation method according to any one of claims 1-5; A fourth reaction is carried out in the fourth mixed reaction system containing the triazine cyclic epoxy resin and the organic ultraviolet absorber, so that the triazine cyclic epoxy resin is grafted with the organic ultraviolet absorber through epoxy groups to obtain a modified epoxy resin.

8. The method for preparing the modified epoxy resin according to claim 7, characterized in that: The temperature of the fourth reaction is 60℃~120℃, and / or the time of the fourth reaction is 1~5h; And / or, the mass ratio of the triazine ring-containing substance to the organic ultraviolet absorber is 10~80:1~5; And / or, the organic ultraviolet absorber includes one or more combinations of 2-(2-hydroxy-5-benzyl)benzotriazole, benzotriazole, salicylates, benzophenones, and substituted acrylonitriles.

9. A modified epoxy resin, characterized in that, It is prepared by the method of any one of claims 7 to 8.

10. A coating, characterized in that, It includes the triazine cycloalcoholic epoxy resin of claim 6 and / or the modified epoxy resin of claim 9.

Images