An epoxy coating comprising a high flow diluent and a method of making the same

Abstract

The application discloses an epoxy coating containing a high-flowing diluent and a preparation method thereof, relates to the technical field of coatings, and has the following components in parts by weight: bisphenol A type epoxy resin 30-50 parts, acrylic resin 20-40 parts, bio-inspired diluent 5-15 parts, modified nano silicon dioxide 5-10 parts, defoaming agent 0.5-1 part, leveling agent 1-2 parts, pigment 4-6 parts, and short-cut glass fiber 20-30 parts. The technical effect is that the bio-inspired diluent has a double-response characteristic, the shearing dilution promotes leveling during construction, the light response increases the resistance to flow hanging after construction, the adhesion and aging resistance are improved, the gradient dispersion process guarantees uniform distribution of nano particles, and the mechanical properties of the coating are strengthened.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of coatings, in particular to an epoxy coating containing a high-level leveling diluent and a preparation method thereof. BACKGROUND

[0002] In the field of coatings, leveling property and sag resistance are the core performance indicators affecting the quality of the coating and the construction effect. The leveling property of the coating refers to its ability to eliminate surface defects and form a smooth coating after construction by itself flowing. The sag resistance refers to the ability of the coating to resist flowing down under the action of gravity and maintain the uniform thickness of the coating when it is applied on a vertical surface. However, there is a natural contradiction between the leveling property and the sag resistance of the coating: when the viscosity of the coating is low, the flowability is good, the coating can quickly level to obtain a smooth surface, but the coating is prone to sagging when it is applied on a vertical surface, resulting in uneven coating thickness and surface quality degradation; if the viscosity of the coating is increased to enhance the sag resistance, the flowability of the coating becomes poor, the coating is difficult to level, and defects such as brush marks and orange peel are prone to occur.

[0003] Traditional epoxy coatings face many difficulties in solving this contradiction. The conventional method is to add a diluent to reduce the viscosity of the coating to improve the leveling property, but this often sacrifices the sag resistance of the coating, and excessive dilution also reduces the crosslinking density of the coating, weakening its mechanical strength and chemical corrosion resistance. On the contrary, simply increasing the thickening agent to increase the viscosity can enhance the sag resistance, but it seriously affects the leveling effect and construction efficiency of the coating. In the fields of industrial painting, building protection and other fields with strict requirements on the quality of the coating, this contradiction between leveling and sag resistance makes it difficult for traditional epoxy coatings to meet the growing demand for high-quality construction, and new technical solutions are needed to balance the relationship between the two and improve the overall performance of the epoxy coating. SUMMARY

[0004] In view of the deficiencies of the prior art, the present application provides an epoxy coating containing a high-level leveling diluent and a preparation method thereof, which effectively solves the performance defects of traditional epoxy coatings and improves the construction performance of the coating and the overall performance of the coating to meet the demand for high-quality epoxy coatings in different fields.

[0005] To achieve the above-mentioned purpose, the present application provides the following technical solution: an epoxy coating containing a high-level leveling diluent, comprising the following components by weight:

[0006] 30-50 parts of bisphenol A type epoxy resin, 20-40 parts of acrylic resin, 5-15 parts of bio-inspired diluent, 5-10 parts of modified nano-silica, 0.5-1 part of defoaming agent, 1-2 parts of leveling agent, 4-6 parts of pigment, and 20-30 parts of chopped glass fiber;

[0007] The bio-inspired diluent is an amphiphilic block copolymer with shear thickening-shear thinning dual response characteristics, and its structure comprises hydrophobic segments (containing photoresponsive groups) and hydrophilic segments (grafted ionic liquid groups).

[0008] Preferably, the hydrophobic segment of the bio-inspired diluent is azobenzene-modified polymethyl methacrylate (Azo-PMMA), and the hydrophilic segment is 1-butyl-3-methyl imidazole hexafluorophosphate ([BMIM][PF6]) grafted polyacrylic acid, and the mass ratio of the two segments is 1:1.5-2.5.

[0009] Preferably, the modified nano-silica is a nano-particle surface modified by silane coupling agent KH-570, with an average particle size of 20-50 nm and a specific surface area of 150-200 m 2 / g.

[0010] Preferably, the short-cut glass fiber is an alkali-resistant glass fiber with a length of 1-3 mm and a diameter of 10-15 μm, and the surface is treated with an epoxy silane coupling agent.

[0011] Preferably, the preparation of the bio-inspired diluent comprises the following steps:

[0012] (a) Synthesis of Azo-PMMA: methyl methacrylate, azobenzene monomer (molar ratio 10:1) and initiator AIBN are reacted at 70°C for 8 hours, and then precipitated and dried;

[0013] (b) Synthesis of ionic liquid grafted polyacrylic acid (PAA-IL): acrylic acid, 1-vinyl-3-butyl imidazole hexafluorophosphate (molar ratio 5:1) are polymerized at 65°C, and then purified by dialysis;

[0014] (c) Mix Azo-PMMA and PAA-IL at a mass ratio of 1:2, add 0.1% photoinitiator TPO, and crush into microspheres after ultraviolet light curing.

[0015] A preparation method of an epoxy coating containing a high leveling diluent, comprising the following steps:

[0016] (1) Pre-mix the resin matrix: add bisphenol A type epoxy resin and bio-inspired diluent at a mass ratio of 3:1-5:1 into a reaction kettle, stir at 500-700 rpm for 30-40 minutes under the conditions of vacuum degree-0.08~ -0.1 MPa and temperature 40-50°C, to form a homogeneous transparent liquid;

[0017] (2) Gradient blending aids: Add acrylic resin, defoamer and leveling agent to the mixture of step (1) in turn, control the feeding rate at 5-10 g / min, adjust the stirring speed in three stages: the first stage 600-800 rpm for 5 minutes, the second stage 1000-1200 rpm for 10 minutes, and the third stage 800-1000 rpm for 5 minutes;

[0018] (3) Nano-enhanced dispersion: Premix modified nano-silica, chopped glass fiber and pigment, then add them to the system of step (2) in three times with an interval of 5 minutes, high-speed dispersion at 40-50°C and 2000-3000 rpm for 40-50 minutes, and use a circulating cooling system to control the system temperature ≤55°C during the dispersion process;

[0019] (4) Directional curing molding: After vacuum degassing (vacuum degree -0.095 MPa, degassing time 20-30 minutes) of the slurry obtained in step (3), spray it on the surface of a high-temperature resistant filter cloth, control the wet film thickness at 150-200 μm, immediately irradiate it with a UV-LED light source with a wavelength of 365 nm and a light intensity of 50-80 mW / cm 2 for 5-10 seconds to form an initial gel network, and then cure it in an oven at 80°C for 30 minutes.

[0020] Preferably, in step (1), the mass ratio of bisphenol A type epoxy resin to bio-inspired diluent is 4:1, the stirring rate is 600 rpm, the vacuum degree is -0.09 MPa, and the stirring time is 35 minutes.

[0021] Preferably, in step (2), the addition rate of acrylic resin is 8 g / min, and the three-stage stirring speeds are 700 rpm (first stage), 1100 rpm (second stage), and 900 rpm (third stage), respectively, and the total mixing time is 20 minutes.

[0022] Preferably, in step (3), the premixing mass ratio of modified nano-silica, chopped glass fiber and pigment is 1:3:0.6, the interval time for three times of feeding is 5 minutes, the disperser speed is 2500 rpm, and the system temperature is maintained at 48°C by circulating cooling water.

[0023] Preferably, in step (4), the UV-LED light source has a wavelength of 365 nm and a light intensity of 65 mW / cm 2 , the irradiation time is 8 seconds, the post-curing temperature is 80°C, the curing time is 30 minutes, and the final coating thickness is 180 μm.

[0024] Compared with the prior art, the present application provides an epoxy coating containing a high-flowing diluent and a preparation method thereof, which has the following beneficial effects: through the biologically inspired diluent with a double-response characteristic, shear thinning is promoted to flow and level during construction, light response is increased to resist sagging after construction, adhesion and aging resistance are improved, gradient dispersion process ensures uniform distribution of nanoparticles, and mechanical properties of the coating are strengthened.

[0025] In terms of process optimization, light-heat synergistic curing significantly shortens the molding time and improves the production efficiency, the excellent leveling and anti-sagging balance performance of the coating reduces the construction technical threshold and reduces rework. DETAILED DESCRIPTION

[0026] The technical solutions in the embodiments of the present application will be clearly and completely described below in combination with the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0027] The reference standard for leveling time test is the standard test method for evaluating the leveling of coatings by using a fixed gap flow coater according to ASTM D4212-98 (2019). The standard sets specific tools and environmental conditions to standardize the test process of the leveling of coatings, so as to ensure the comparability of the test results of the leveling time of different coatings.

[0028] Test steps:

[0029] Prepare the tools: select a flow coater with a fixed gap of 100 μm, ensure that its surface is smooth and flat without any wear or contamination; prepare a clean and flat glass plate with a size of not less than 20 cm x 20 cm.

[0030] Prepare the sample: thoroughly stir the epoxy coating to be tested to ensure uniform dispersion of the components without precipitation or stratification.

[0031] Coating operation: place the flow coater at one end of the glass plate, pour an appropriate amount of epoxy coating into the gap of the flow coater, and quickly push the flow coater along the surface of the glass plate at a uniform speed to evenly coat the epoxy coating on the glass plate to form a wet film.

[0032] Timing observation: start timing from the moment when the coating is completed, and continuously observe the surface of the wet film under standard environmental conditions (temperature 23±2℃, relative humidity 50±5%) using a low-power magnifying glass (such as 5-10 times). When the surface of the wet film is completely smooth without any visible brush marks, flow marks or depressions, stop timing and record the time as the leveling time.

[0033] Anti-sag thickness test reference standard: Refer to ISO 12635:1998 "Determination of sagging of pigmented coatings and paints", which establishes a unified method and evaluation index for measuring the ability of coatings to resist sagging on vertical surfaces due to gravity.

[0034] Test steps:

[0035] Prepare the sample plate: Select a tin plate with dimensions of 15 cm x 10 cm, and surface polishing and degreasing treatment to ensure a clean surface with good adhesion.

[0036] Coating preparation: Use an airbrush to spray epoxy coating on the tin plate, keep the airbrush distance from the sample plate surface at 15-20 cm, and control the spraying pressure at 0.3-0.4 MPa. Increase the coating thickness gradually, wait for 5-10 minutes after each spraying to allow the solvent to evaporate properly. Measure the wet film thickness at different positions on the sample plate with a wet film thickness meter and record 3-5 points after each spraying.

[0037] Sag observation: Hang the sprayed sample plate vertically in standard environmental conditions (temperature 23±2℃, relative humidity 50±5%), and wait for the coating to dry. The drying time depends on the characteristics of the coating, generally 24-48 hours. Observe the coating surface, and when obvious sag marks (such as tear drop-shaped or corrugated) are found, record the corresponding wet film thickness at this time, which is the anti-sag thickness.

[0038] 180℃ adhesion test reference standard: Follow the grid method in ASTM D3359-21 "Standard Test Methods for Measuring Adhesion by Tape Test", which is suitable for evaluating the adhesion between coating and substrate under different temperature conditions.

[0039] Test steps:

[0040] Sample preparation: Apply epoxy coating evenly on a metal substrate (such as carbon steel sheet) with dimensions of 10 cm x 10 cm, and follow the specified curing process for curing. After curing, place the sample plate in an oven at 180℃ for 30 minutes, then take it out and cool it to room temperature naturally.

[0041] Grid operation: Use a sharp grid tool to draw 100 small squares with a side length of 1 mm on the coating surface in a crisscross manner. The tool should be perpendicular to the coating surface and the force should be uniform to ensure that the coating is cut through to the substrate surface.

[0042] Adhesive tape sticking: Choose a semi-transparent pressure-sensitive adhesive tape with a width of 25 mm, and firmly stick it to the grid area. Use fingers or rubber rollers to repeatedly roll on the adhesive tape to ensure that there are no bubbles or gaps between the adhesive tape and the coating.

[0043] Tape peel: After 1 minute of adhesive tape application, quickly peel the tape from the coating surface at a 180° angle, maintaining a speed of 200-300 mm / min.

[0044] Result rating: According to the adhesion rating standards specified in ASTM D3359-21, observe the coating detachment and rate accordingly. 5B indicates that the cut edges are completely smooth with no detachment at the grid edges; 4B indicates a small amount of coating detachment at the intersection of the cuts, but the detached area does not exceed 5%; 3B indicates coating detachment at the edges of the cuts and at the intersection, with a detached area between 5% and 15%; 2B indicates a detached area between 15% and 35%; IB indicates a detached area between 35% and 65%; and 0B indicates a detached area exceeding 65%.

[0045] Yellowing value test reference standard: Refer to the GB / T 23987-2009 "Artificial Weathering Exposure of Paint and Varnish Coatings - Exposure to Fluorescent UV and Water" standard, which specifies the simulation of ultraviolet radiation in natural environments through fluorescent UV lamps, combined with condensed water to simulate a humid environment, testing the degree of yellowing of the coating under accelerated aging conditions.

[0046] Test procedure:

[0047] Sample preparation: Apply the epoxy coating to a white aluminum panel measuring 7 cm x 5 cm, forming a uniform coating and curing according to the specified process.

[0048] Instrument settings: Set the temperature of the aging test chamber to 60 ± 3°C and the relative humidity to 50 ± 5%, with a wavelength range of 315-400 nm for the fluorescent UV lamp, controlling the irradiance at 0.89 W / (m 2 ·nm).

[0049] Sample placement: Place the prepared sample in the aging test chamber, maintaining a distance of approximately 50 cm between the sample and the light source to ensure uniform exposure to light and humidity.

[0050] Test procedure: Turn on the aging test chamber and expose the sample to the specified conditions for 30 minutes continuously.

[0051] Data measurement: After the test is completed, remove the sample and place it in a standard environment for 1 hour to allow the temperature and humidity to reach equilibrium. Use a colorimeter to measure the color change of the sample before and after the test, recording the yellowing value Δb. The larger the yellowing value, the more severe the yellowing of the coating.

[0052] Test-related instruments:

[0053] Leveling time test:

[0054] Fixed gap flow coater: Model BYK-4420, which adopts high-precision machining process, with gap accuracy of ±1 μm, fixed gap set to 100 μm, can ensure the consistency of coating thickness, suitable for leveling test of coatings with various viscosity ranges.

[0055] Low-power magnifying glass: Magnus ML300 is selected, with magnification of 5-10 times adjustable, clear field of view, stable imaging, which can help the tester to accurately observe the defect changes on the surface of the wet film of the coating, and ensure the accuracy of the leveling time measurement.

[0056] Thermohygrograph: Model Testo645, which can monitor the environmental temperature and relative humidity in real time, the temperature measurement range is-20-60℃, the accuracy is ±0.3℃; the relative humidity measurement range is 0-100% RH, the accuracy is ±1.5% RH, which meets the strict requirements of the standard for the test environment (temperature 23±2℃, relative humidity 50±5%).

[0057] Anti-sagging thickness test:

[0058] Spray gun: SATAjet5000B is recommended, which has excellent atomization effect and precise flow control, the spray gun caliber can be selected according to the viscosity of the coating, adjusted between 0.8-2.0mm, the spraying pressure is stable at 0.3-0.4MPa, which can uniformly spray the coating on the sample plate.

[0059] Wet film thickness gauge: PosiTector6000F1 is adopted, which has fast and accurate measurement performance, the measurement range is 0-2000μm, the accuracy is ±2%, which can quickly obtain the wet film thickness data at different positions of the sample plate, ensuring the representativeness of the test results.

[0060] Suspension device: Customized stainless steel suspension rack with good load-bearing capacity and stability, which can ensure the vertical suspension of the sample plate and avoid test errors caused by inclined suspension.

[0061] 180℃ adhesion test:

[0062] Oven: Model Binder FD115, temperature control range is room temperature-300℃, temperature fluctuation is ±0.3℃, which can accurately control the heating rate and holding time, ensuring that the sample plate is stably treated at 180℃ for 30 minutes.

[0063] Grid cutter: QFH type grid cutter is selected, which is equipped with high-hardness alloy blade, can draw 1mm×1mm standard grid, with high grid spacing accuracy, can complete the drawing of 100 grids at one time, improving the test efficiency.

[0064] Pressure-sensitive adhesive tape: 3M 600 test tape, width 25mm, with stable adhesion and good flexibility, can closely adhere to the coating surface, ensure the accuracy of the tape peeling test.

[0065] Tensile testing machine (for tape peeling): Instron 3367, with precise tension control and speed adjustment function, can realize 180° angle, 200-300mm / min tape peeling speed, ensure the consistency of test conditions.

[0066] Yellowness value test:

[0067] Aging test chamber: QUV / se, equipped with fluorescent ultraviolet light, wavelength range 315-400nm, irradiance can be adjusted in the range of 0-1.5W / (m 2 ·nm), temperature control range 10-80℃, relative humidity control range 30-95%RH, can accurately simulate the standard specified artificial climate aging environment.

[0068] Color difference meter: Konica Minolta CM-26dG, with high-precision color measurement capability, can accurately capture the color change before and after the coating test, and obtain the yellowness value data.

[0069] Example one

[0070] An epoxy coating containing a high-flow diluent, the components are weighed as follows: bisphenol A type epoxy resin 30 parts, acrylic resin 20 parts, bio-inspired diluent 5 parts, modified nano-silica 5 parts, defoamer 0.5 parts, leveling agent 1 part, pigment 4 parts, chopped glass fiber 20 parts. The preparation of bio-inspired diluent is carried out according to the above steps, and the mass ratio of two segments is 1:1.5.

[0071] The preparation method of epoxy coating is as follows:

[0072] (1) Premix resin matrix: bisphenol A type epoxy resin and bio-inspired diluent are added to the reaction kettle according to the mass ratio of 3:1, stirred at 500rpm for 30 minutes under the condition of vacuum degree-0.08MPa and temperature 40℃, forming a homogeneous transparent liquid;

[0073] (2) Gradient blending aid: add acrylic resin, defoamer and leveling agent to the mixture of step (1) in turn, the addition rate is 5g / min, adjust the stirring speed in three stages: the first stage 600rpm mixing for 5 minutes, the second stage 1000rpm mixing for 10 minutes, the third stage 800rpm mixing for 5 minutes;

[0074] (3) Nano-enhanced dispersion: The modified nano-silica, chopped glass fiber and pigment were pre-mixed at a mass ratio of 1:4:0.8, then added into the system of step (2) in three times with an interval of 5 minutes, and high-speed dispersed at 40°C and 2000 rpm for 40 minutes. During the dispersion process, a circulating cooling system was used to control the system temperature ≤55°C;

[0075] (4) Directional curing molding: The slurry obtained in step (3) was vacuum degassed (vacuum degree-0.095 MPa, degassing time 20 minutes), then sprayed on the surface of a high-temperature resistant filter cloth, and the wet film thickness was controlled at 150 μm. Immediately, a UV-LED light source with a wavelength of 365 nm and a light intensity of 50 mW / cm 2 was used for irradiation for 5 seconds to form an initial gel network, and then cured in an oven at 80°C for 30 minutes.

[0076] Example Two

[0077] An epoxy coating containing a high-levelling diluent, the components were weighed as follows: bisphenol A type epoxy resin 50 parts, acrylic resin 40 parts, bio-inspired diluent 15 parts, modified nano-silica 10 parts, defoamer 1 part, leveling agent 2 parts, pigment 6 parts, chopped glass fiber 30 parts. The bio-inspired diluent was prepared according to the above steps, and the mass ratio of two segments was 1:2.5.

[0078] The preparation method of the epoxy coating is as follows:

[0079] (1) Pre-mixing resin matrix: Bisphenol A type epoxy resin and bio-inspired diluent were added into a reaction kettle at a mass ratio of 5:1, and stirred at 700 rpm for 40 minutes under the conditions of vacuum degree-0.1 MPa and temperature 50°C, forming a homogeneous transparent liquid;

[0080] (2) Gradient blending aid: The acrylic resin, defoamer and leveling agent were added into the mixture of step (1) in turn at a rate of 10 g / min, and the stirring speed was adjusted in three stages: 800 rpm for 5 minutes in the first stage, 1200 rpm for 10 minutes in the second stage, and 1000 rpm for 5 minutes in the third stage;

[0081] (3) Nano-enhanced dispersion: The modified nano-silica, chopped glass fiber and pigment were pre-mixed at a mass ratio of 1:2:0.4, then added into the system of step (2) in three times with an interval of 5 minutes, and high-speed dispersed at 50°C and 3000 rpm for 50 minutes. During the dispersion process, a circulating cooling system was used to control the system temperature ≤55°C;

[0082] (4) Directional curing molding: the slurry obtained in step (3) is vacuum degassed (vacuum degree-0.095 MPa, degassing time 30 minutes) and then sprayed on the surface of a high-temperature-resistant filter cloth, with the wet film thickness controlled at 200 μm, immediately irradiated for 10 seconds with a UV-LED light source with a wavelength of 365 nm and a light intensity of 80 mW / cm 2 , to form an initial gel network, and then cured in an 80°C oven for 30 minutes.

[0083] Example Three

[0084] An epoxy coating containing a high-levelling diluent, the components are weighed as follows: bisphenol A type epoxy resin 40 parts, acrylic resin 30 parts, bio-inspired diluent 10 parts, modified nano-silica 8 parts, defoamer 0.8 parts, levelling agent 1.5 parts, pigment 5 parts, chopped glass fiber 25 parts. The bio-inspired diluent is prepared according to the above steps, and the mass ratio of the two segments is 1:2.

[0085] The preparation method of the epoxy coating is as follows:

[0086] (1) Premix resin matrix: bisphenol A type epoxy resin and bio-inspired diluent are added to the reaction kettle at a mass ratio of 4:1, stirred at 600 rpm for 35 minutes under the conditions of vacuum degree-0.09 MPa and temperature 45°C, to form a homogeneous transparent liquid;

[0087] (2) Gradient blending aid: acrylic resin, defoamer and levelling agent are added to the mixture of step (1) in turn at a rate of 8 g / min, and the stirring speed is adjusted in three stages: 700 rpm for 5 minutes in the first stage, 1100 rpm for 10 minutes in the second stage, and 900 rpm for 5 minutes in the third stage;

[0088] (3) Nano-enhanced dispersion: modified nano-silica, chopped glass fiber and pigment are pre-mixed at a mass ratio of 1:3:0.6 and then added to the system of step (2) in three times with an interval of 5 minutes each, and high-speed dispersed at 48°C and 2500 rpm for 45 minutes, and the system temperature is controlled to be ≤55°C during the dispersion process by using a circulating cooling system;

[0089] (4) Directional curing molding: the slurry obtained in step (3) is vacuum degassed (vacuum degree-0.095 MPa, degassing time 25 minutes) and then sprayed on the surface of a high-temperature-resistant filter cloth, with the wet film thickness controlled at 180 μm, immediately irradiated for 8 seconds with a UV-LED light source with a wavelength of 365 nm and a light intensity of 65 mW / cm 2 , to form an initial gel network, and then cured in an 80°C oven for 30 minutes.

[0090] Example Four

[0091] An epoxy coating comprising a high leveling diluent, the components are weighed as follows: bisphenol A type epoxy resin 35 parts, acrylic resin 25 parts, bio-inspired diluent 8 parts, modified nano-silica 6 parts, defoamer 0.6 parts, leveling agent 1.2 parts, pigment 4.5 parts, chopped glass fiber 22 parts. The bio-inspired diluent is prepared according to the above steps, and the mass ratio of the two segments is 1:1.8.

[0092] The other steps are the same as example two.

[0093] Example five

[0094] An epoxy coating comprising a high leveling diluent, the components are weighed as follows: bisphenol A type epoxy resin 45 parts, acrylic resin 35 parts, bio-inspired diluent 12 parts, modified nano-silica 9 parts, defoamer 0.9 parts, leveling agent 1.8 parts, pigment 5.5 parts, chopped glass fiber 28 parts. The bio-inspired diluent is prepared according to the above steps, and the mass ratio of the two segments is 1:2.2.

[0095] The other steps are the same as example two.

[0096] Comparative example one

[0097] The bio-inspired diluent is replaced by a common diluent (xylene), and the other components and preparation methods are the same as example two.

[0098] Comparative example two

[0099] The gradient dispersion process is not used, all the additives are added at once, and the stirring speed is always kept at 800 rpm, and the other steps are the same as example two.

[0100] Comparative example three

[0101] The light-heat synergistic curing is not used, only 80°C oven curing for 60 minutes is used, and the other steps are the same as example two.

[0102] Comparative example four

[0103] The bio-inspired diluent only contains hydrophobic segments (azobenzene modified polymethyl methacrylate), and does not contain hydrophilic segments, and the other steps are the same as example two.

[0104] Comparative example five

[0105] The bio-inspired diluent only contains hydrophilic segments (1-butyl-3-methyl imidazole hexafluorophosphate grafted polyacrylic acid), and does not contain hydrophobic segments, and the other steps are the same as example two.

[0106] Comparative example six

[0107] A common epoxy coating purchased from the market.

[0108] Comparative Example Six uses a commonly used epoxy coating on the market, model PPG Dura-Pox 100, the main components of which are as follows:

[0109] Epoxy resin: bisphenol A type epoxy resin, content about 40-50%, curing agent: polyamide curing agent, content 15-25%, solvent: mixed solvent of dimethylbenzene and butanol, content 20-30%, pigment and filler: including titanium dioxide, calcium carbonate, etc., content 10-15%, additives: including leveling agent, defoaming agent, etc., total content 1-5%.

[0110] The epoxy coatings obtained in Examples One to Five and Comparative Examples One to Six are numbered in groups as HYSZ-1001, HYSZ-1002, HYSZ-1003, HYSZ-1004, HYSZ-1005, HYSZ-1006, HYSZ-1007, HYSZ-1008, HYSZ-1009, HYSZ-10010, HYSZ-10011, and the leveling time, anti-sagging thickness, 180°C adhesion, and yellowing value of the products of the examples and comparative examples are tested, and the specific test results are shown in Table 1 and Table 2.

[0111] Table 1 is the test results of leveling time and anti-sagging thickness

[0112] Test No. Leveling time (min) Anti-sag thickness (μm) HYSZ-1001 4.5 130 HYSZ-1002 3 160 HYSZ-1003 2.5 170 HYSZ-1004 4 140 HYSZ-1005 3.5 150 HYSZ-1006 9 75 HYSZ-1007 8 85 HYSZ-1008 8 90 HYSZ-1009 7 110 HYSZ-1010 7 105 HYSZ-1011 10 70

[0113] Table 2 is the test results of 180°C adhesion and yellowing value

[0114] Test No. 180°C adhesion (grade) Yellowing value Δb (220°C / 30 min) HYSZ-1001 2 3.2 HYSZ-1002 1 1.8 HYSZ-1003 1 1.5 HYSZ-1004 2 2.8 HYSZ-1005 1 2 HYSZ-1006 4 7 HYSZ-1007 4 6.5 HYSZ-1008 4 6 HYSZ-1009 3 5.5 HYSZ-1010 3 5.2 HYSZ-1011 5 8

[0115] The comprehensive test results show that: Comparative Example One uses a common diluent, the leveling time is long and the anti-sagging thickness is low, while the bio-inspired diluent in the examples has the shear thickening-shear thinning dual response characteristics, presents shear thinning characteristics during construction, reduces the viscosity of the coating, and realizes rapid leveling; after construction, the light response group promotes the increase of viscosity, improves the anti-sagging ability, and effectively balances the contradiction between leveling and anti-sagging. Comparative Examples Four and Five respectively lack hydrophilic segments or hydrophobic segments, and the performance is not as good as the examples. The bio-inspired diluent with complete structure in the present application not only improves the leveling and anti-sagging performance, but also participates in the crosslinking of the coating, improving the adhesion and aging resistance of the coating;

[0116] The comparative example two does not adopt the gradient dispersion process, resulting in uneven dispersion of nanoparticles, and the test data shows that the performance is lower than that of the embodiment. The present application controls the stirring speed and feeding sequence in stages to ensure uniform dispersion of modified nano-silica and other additives, enhance the mechanical properties and stability of the coating, and thus improve the anti-sagging thickness, adhesion and other indicators. Improve the curing efficiency and quality: the comparative example three only uses a single thermal curing method, and compared with the embodiment, the curing effect is poor, resulting in poorer performance of leveling property, adhesion and the like. The light-thermal synergistic curing of the present application quickly triggers the diluent to form a gel network under UV light, realizes rapid forming, and shortens the leveling time; the post-curing further improves the crosslinking density, enhances the hardness, wear resistance and chemical corrosion resistance of the coating, reduces the yellowing value, and improves the comprehensive performance and durability of the coating.

[0117] In summary, the present application overcomes the performance defects of traditional epoxy coatings by using innovative technologies such as bio-inspired diluent, gradient dispersion process and light-thermal synergistic curing, greatly improves the comprehensive performance of the coating, and has significant technical value and broad application prospect.

[0118] The above is only a specific embodiment of the present application, but the technical features of the present application are not limited thereto. Any simple change, equivalent replacement or modification made on the basis of the present application to solve the same technical problem and achieve the same technical effect is also covered by the protection scope of the present application.

Claims

1. An epoxy coating comprising a high-leveling diluent, characterized in that, It contains the following components in parts by weight: 30-50 parts of bisphenol A type epoxy resin, 20-40 parts of acrylic resin, 5-15 parts of bio-inspired diluent, 5-10 parts of modified nano silica, 0.5-1 part of defoamer, 1-2 parts of leveling agent, 4-6 parts of pigment, and 20-30 parts of chopped glass fiber. The bio-inspired diluent is an amphiphilic block copolymer with shear thickening-shear thinning dual-response properties, and its structure includes hydrophobic segments and hydrophilic segments; The bio-inspired diluent has a hydrophobic segment of azobenzene-modified polymethyl methacrylate (Azo-PMMA) and a hydrophilic segment of 1-butyl-3-methylimidazolium hexafluorophosphate-grafted polyacrylic acid, with a mass ratio of 1:1.5-2.5 between the two segments. The modified nano-silica consists of nanoparticles surface-modified with silane coupling agent KH-570, with an average particle size of 20-50 nm and a specific surface area of ​​150-200 m². 2 / g; The preparation of the bio-inspired diluent includes the following steps: (a) Synthesis of Azo-PMMA: Methyl methacrylate, azobenzene monomer and initiator AIBN were reacted at 70°C for 8 hours, and the precipitate was dried; (b) Synthesis of ionic liquid-grafted polyacrylic acid (PAA-IL): Acrylic acid and 1-vinyl-3-butylimidazolium hexafluorophosphate were polymerized at 65°C and purified by dialysis; (c) Mix Azo-PMMA and PAA-IL at a mass ratio of 1:2, add 0.1% photoinitiator TPO, cure under ultraviolet light and then pulverize into microspheres.

2. An epoxy coating containing a high-leveling diluent according to claim 1, characterized in that: The chopped glass fibers are alkali-resistant glass fibers with a length of 1-3 mm and a diameter of 10-15 μm, and the surface is treated with an epoxy silane coupling agent.

3. A method for preparing an epoxy coating comprising a high-leveling diluent as described in any one of claims 1-2, characterized in that: Includes the following steps: (1) Premixed resin matrix: Bisphenol A type epoxy resin and bio-inspired diluent are added to the reactor at a mass ratio of 3:1-5:

1. Under vacuum conditions of -0.08~-0.1MPa and temperature of 40-50℃, the mixture is stirred at 500-700rpm for 30-40 minutes to form a homogeneous transparent liquid. (2) Gradient blending aids: Add acrylic resin, defoamer and leveling agent to the mixture in step (1) in sequence, control the feeding rate to 5-10 g / min, and adjust the stirring speed in three stages: the first stage is 600-800 rpm for 5 minutes, the second stage is 1000-1200 rpm for 10 minutes, and the third stage is 800-1000 rpm for 5 minutes. (3) Nano-reinforced dispersion: After premixing the modified nano-silica, chopped glass fiber and pigment, add them to the system of step (2) in three parts, with an interval of 5 minutes each time. Disperse at high speed for 40-50 minutes at 40-50℃ and 2000-3000rpm. During the dispersion process, use a circulating cooling system to control the system temperature ≤55℃. (4) Directional curing and molding: After vacuum degassing, the slurry obtained in step (3) is sprayed onto the surface of high temperature resistant filter cloth. The wet film thickness is controlled at 150-200μm. Immediately irradiate it with a UV-LED light source with a wavelength of 365nm and a light intensity of 50-80mW / cm² for 5-10 seconds to form an initial gel network. Then cure it in an oven at 80℃ for 30 minutes.

4. The method for preparing an epoxy coating containing a high-leveling diluent according to claim 3, characterized in that: In step (1), the mass ratio of bisphenol A epoxy resin to bio-inspired diluent is 4:1, the stirring speed is 600 rpm, the vacuum degree is -0.09 MPa, and the stirring time is 35 minutes.

5. The method for preparing an epoxy coating containing a high-leveling diluent according to claim 3, characterized in that: In step (2), the addition rate of acrylic resin is 8 g / min, the stirring speeds in the three stages are 700 rpm, 1100 rpm and 900 rpm respectively, and the total mixing time is 20 minutes.

6. The method for preparing an epoxy coating containing a high-leveling diluent according to claim 3, characterized in that: In step (3), the premixed mass ratio of modified nano silica, chopped glass fiber and pigment is 1:3:0.6, the interval between the three feedings is 5 minutes, the speed of the disperser is 2500 rpm, and the system temperature is maintained at 48℃ by circulating cooling water.

7. The method for preparing an epoxy coating containing a high-leveling diluent according to claim 3, characterized in that: In step (4), the UV-LED light source has a wavelength of 365nm, a light intensity of 65mW / cm², an irradiation time of 8 seconds, a post-curing temperature of 80℃, a curing time of 30 minutes, and a final coating thickness of 180μm.