Quick-drying high-adhesion modified curing agent and application method thereof
By leveraging the synergistic effect of modified alicyclic amines, polyamine ethers, and acetylacetone trimetallic complexes, the problem of imbalance between curing efficiency and performance in the curing agent system was solved, achieving fast drying and high adhesion of the coating, and improving the long-term adhesion stability and overall performance of the coating.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-01-09
- Publication Date
- 2026-03-27
AI Technical Summary
Existing curing agent systems cannot precisely control the curing rate and final performance, resulting in excessively long surface drying and hard drying times or rapid curing leading to stress concentration inside the coating, making it prone to cracking and reducing adhesion, thus failing to meet the long-term stability requirements for high adhesion.
A modified curing agent composed of modified alicyclic amines, polyamine ethers, and acetylacetone trimetallic complexes is used to precisely control the curing rate and film-forming properties by chemically modifying the substrate and functionalizing the micro-nano structure, thereby improving catalytic efficiency and the adhesion between the coating and the substrate.
It shortens the surface drying and hard drying time of the coating, distributes the internal stress of the coating evenly, improves tensile strength and flexural strength, significantly enhances the adhesion between the coating and the substrate, and improves weather resistance and chemical resistance, thus meeting the needs of high-end industrial coating for fast drying, high adhesion and high stability.
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Abstract
Description
TECHNICAL FIELD
[0001] The application belongs to the technical field of coating curing, and particularly relates to a quick-drying high-adhesion modified curing agent and an application method thereof. BACKGROUND
[0002] In many industrial fields such as industrial protection, automobile parts, marine engineering equipment, and electronic component packaging, the equipment is in a harsh environment for a long time, and the coating needs to have long-term adhesion stability and comprehensive properties such as weather resistance and chemical resistance. The coating needs to solve the problem of rapid drying during use, especially in severe winter or alternating seasons, which is prone to curing difficulty or cannot be constructed.
[0003] In the prior art, a common curing system usually uses a single amine curing agent such as an alicyclic amine or a polyether amine alone, and is prepared by mixing in a conventional proportion. However, the single amine curing agent system cannot accurately control the curing rate and the final performance, and is prone to problems such as overlong surface drying and real drying time, or internal stress concentration and easy cracking of the coating due to rapid curing, and cannot meet the requirements of quick drying and stable film formation. In order to improve the quick drying efficiency, an accelerator is usually added to the curing agent. The accelerator in the prior art is usually a simple metal salt, a single metal complex such as Zn or Al, or a double metal complex such as a Zn / Al metal complex. Although the accelerator has a certain catalytic effect, the catalytic activity is weak, and the curing process cannot be effectively accelerated. Moreover, the accelerator has an adverse effect on the long-term stability of the coating, such as weather resistance and chemical resistance, and is prone to problems such as yellowing and powdering of the coating in the later period.
[0004] In addition to the above technical problems, the surface treatment of the coating in the prior art is usually conventional polishing or simple cleaning, and the surface micro-nano structure is not designed specifically. The coating and the substrate are only combined by physical adsorption and simple chemical bonds, and cannot form an effective anchoring effect. In a complex environment such as cold and hot cycles or external force impact, the adhesion is prone to decrease, and the coating is prone to fall off, which cannot meet the requirements of long-term stability of high adhesion, and cannot meet the dual standards of quick drying and high adhesion in industrialized and building decoration scenes with high construction efficiency requirements.
[0005] In summary, the existing curing system has the problems of simple physical mixing of the two-component amine curing agent, no structural modification, limited performance control, single metal catalytic efficiency and stability of the acetylacetone metal complex accelerator, and limited adhesion improvement of the substrate surface etching only relying on the general process and no specific structure design. Therefore, it is necessary to propose a solution that breaks through the limitation of simple compounding in the prior art, further shortens the curing time, enhances the long-term adhesion stability of the coating and the substrate, and improves the comprehensive properties such as weather resistance and chemical resistance of the coating. SUMMARY
[0006] The present application aims to solve the technical problems of poor balance between curing efficiency and performance, poor adhesion, and reduction of long-term adhesion stability of coating and substrate existing in the prior art curing agent, and proposes a fast-drying high-adhesion modified curing agent and its application method.
[0007] To achieve the above-mentioned purpose, the present application provides the following technical solutions. A fast-drying high-adhesion modified curing agent comprises the following raw materials by weight: modified alicyclic amine 40-60 parts, modified polyamine ether 40-60 parts, and acetylacetone three-metal complex accelerator 4-6 parts.
[0008] The present application realizes precise regulation of curing rate and film forming performance by modifying the chemical structure of alicyclic amine and polyether amine respectively, and then compounding them in a specific ratio, and utilizing the synergistic effect of the modified functional groups, solves the performance fluctuation problem of traditional physical mixing system; at the same time, the acetylacetone three-metal complex accelerator is introduced to improve the catalytic efficiency, and through the synergistic effect of the modified two-component amine curing agent and the three-metal accelerator, the surface dry time and the real dry time of the coating are shortened, the internal stress of the coating is uniformly dispersed, the tensile strength and the bending strength are improved, and the film forming quality and the mechanical properties are improved.
[0009] Preferably, the modified alicyclic amine is prepared by the following method: under nitrogen protection at 60-70 DEG C, alicyclic amine is reacted with propylene oxide at a molar ratio of 1:1.2-1.5 for 2-3h to obtain modified alicyclic amine with a molecular weight of 800-1000. The polyoxypropylene side chain is introduced by propylene oxide reaction to improve the compatibility with resin and the curing flexibility.
[0010] Preferably, the modified polyamine ether is prepared by the following method: at 40-50 DEG C, polyether amine is reacted with maleic anhydride at a molar ratio of 1:0.8-1.0 for 1.5-2h to obtain modified polyether amine with an acid value of 20-30mgKOH / g. The carboxyl functional group is introduced by maleic anhydride reaction to enhance the chemical bonding ability with the substrate.
[0011] Preferably, the acetylacetone metal complex accelerator is acetylacetone Zn / Al / La three-metal complex.
[0012] Preferably, the acetylacetone Zn / Al / La trimetallic complex is prepared by the following method: acetylacetone with a concentration of 0.5 mol / L is mixed with Zn(NO3)2, AlCl3 and La(NO3)3 in a molar ratio of 3:1:1:0.5, ethanol is used as a solvent, ammonia water is added dropwise to adjust the pH to 6.0-6.5, after reaction for 3-4 h, centrifugal separation and vacuum drying for 8 h, an acetylacetone Zn / Al / La trimetallic complex with a particle size of 10-15 nm is prepared.
[0013] The acetylacetone Zn / Al / La trimetallic complex is selected in the application, wherein Zn 2+ dominates the initial reaction of accelerated curing, Al 3+ enhances the cross-linking density of the coating, and La 3+ suppresses the migration of metal ions, and after 500 h of artificial accelerated aging test, the yellowing index of the coating is only 1.8-2.2, which is reduced by 40%-50% compared with the bimetallic complex system; after soaking in 5% sulfuric acid and 5% sodium hydroxide solution for 72 h, the adhesion retention rate of the coating reaches more than 95%, solving the problem of insufficient weather resistance and chemical resistance caused by traditional accelerators.
[0014] Another object of the application is to provide a preparation method of a quick-drying high-adhesion modified curing agent, comprising the following steps: slowly adding modified alicyclic amine and modified polyether amine into a reaction kettle under the conditions of 28-32℃ and a stirring rate of 250-300 r / min, continuously stirring for 40-50 min under a nitrogen atmosphere, and uniformly mixing to obtain a modified curing agent system; adding acetylacetone Zn / Al / La trimetallic complex into the modified curing agent system in 2-3 times with an interval of 5 min each time, and continuously stirring for 20-25 min to obtain the modified curing agent.
[0015] The process design of nitrogen protection stirring and batch addition of accelerators is adopted in the application, which ensures the stability of functional groups in the modified curing agent and the uniform dispersion of accelerators, avoids problems such as uneven dispersion and oxidation of functional groups caused by traditional one-time mixing, and lays a foundation for efficient curing.
[0016] The application further provides an application method of the quick-drying high-adhesion modified curing agent, comprising the following steps: (1) substrate pretreatment: 80-100 mesh white corundum sand is used for sand blasting treatment on the surface of the substrate under the pressure of 0.5 MPa, and the substrate is ultrasonically cleaned with acetone for 15 min to remove the oxide layer; a gradient micron groove with alternating shallow and deep grooves is etched on the surface of the substrate by using a fiber laser; the substrate after laser etching is immersed in a composite etching liquid, and reacted at 45-50 DEG C for 12-18 min to form a nano protrusion with a height of 80-150 nm and a diameter of 50-80 nm on the inner wall of the micron groove and the interstitial region; after the substrate is washed with deionized water, it is dried at 75-80 DEG C for standby; (2) coating curing: the modified curing agent and the coating are uniformly coated on the surface of the treated substrate in a mass ratio of 1:4-1:5 by spraying / scratching, and the coating thickness is controlled at 80-120 mu m, and the coating is cured in an environment of 23-25 DEG C and a relative humidity of 45%-55%.
[0017] The present application is processed by pretreatment, laser etching, chemical etching and post-treatment, and the surface of the substrate is designed with a gradient micro-nano structure, so that the contact area of the coating with the substrate is increased by 2-3 times, the chemical bonding sites are increased by more than 50%, the tensile shear strength is increased by more than 45%, and the long-term adhesion requirement under complex environment is met.
[0018] Preferably, the depth of the shallow groove in step (1) is 5-8 mu m, and the width is 10-15 mu m; the depth of the deep groove is 12-15 mu m, and the width is 25-30 mu m.
[0019] Preferably, the composite etching liquid in step (1) is composed of 5% sulfuric acid, 0.5% phosphoric acid and 0.1% fluoride.
[0020] Compared with the prior art, the present application has the following advantages: 1. The modified curing agent of the present application is synergistically acted by modified double-component modified alicyclic amine and three-metal accelerators, so that the surface drying time of the coating is shortened to 1-1.5 h at room temperature, which is shortened by more than 30% compared with the existing traditional curing agent; the dry time is shortened to 4-5 h, which is shortened by more than 25% compared with the existing traditional curing agent; and the internal stress of the coating is uniformly dispersed, the stress value is reduced to below 5 MPa, there is no cracking phenomenon, the tensile strength is increased by 35-45%, the bending strength is increased by 30-40%, and the film forming quality and mechanical properties are significantly improved.
[0021] 2. The modified curing agent of the present application selects acetylacetone Zn / Al / La three-metal complex as an accelerator, which inhibits the migration of metal ions through La 3+ After 500 h of artificial accelerated aging test, the yellowing index of the coating is significantly reduced to only 1.8-2.2, and after soaking in 5% sulfuric acid and 5% sodium hydroxide solution for 72 h, the coating adhesion retention rate still reaches more than 95%, solving the problem of insufficient weather resistance and chemical resistance caused by traditional accelerators.
[0022] 3. The application improves the contact area of the coating with the substrate by 2-3 times, increases the chemical bonding sites by more than 50%, and achieves a 0 level in the adhesion test. After 60 times of cold and hot cycle at -25℃-85℃ and 120 times of impact test, the coating has no peeling, peeling, and cracking phenomenon; the tensile shear strength of the substrate of different materials is improved by more than 45%, meeting the long-term adhesion requirements in complex environments.
[0023] 4. The application shortens the curing time, enhances the long-term adhesion stability of the coating and the substrate, and improves the weather resistance and chemical resistance of the coating, meeting the technical requirements of fast drying, high adhesion and high stability of the cured coating in high-end industrial coating applications such as automobile parts, marine engineering equipment and electronic component packaging. DETAILED DESCRIPTION
[0024] The technical solutions in the embodiments of the application will be clearly and completely described below with reference to the embodiments of the application. Obviously, the described embodiments are only part of the embodiments of the application, not all. The embodiments in the application and the features in the embodiments can be combined with each other without conflict.
[0025] A modified curing agent with fast drying and high adhesion force comprises the following raw materials by weight: modified alicyclic amine 40-60 parts, modified polyamine ether 40-60 parts, and acetylacetone three-metal complex accelerator 4-6 parts.
[0026] It should be noted that the modified alicyclic amine is prepared by the following method: under the protection of nitrogen at 60℃, alicyclic amine is reacted with propylene oxide at a molar ratio of 1:1.2 for 3h to obtain modified alicyclic amine 1# with a molecular weight of 800.
[0027] It should be noted that the modified alicyclic amine is prepared by the following method: under the protection of nitrogen at 65℃, alicyclic amine H-1230 is reacted with propylene oxide at a molar ratio of 1:1.3 for 2.5h to obtain modified alicyclic amine 2# with a molecular weight of 900.
[0028] It should be noted that the modified alicyclic amine is prepared by the following method: under the protection of nitrogen at 70℃, alicyclic amine is reacted with propylene oxide at a molar ratio of 1:1.5 for 2h to obtain modified alicyclic amine 3# with a molecular weight of 1000.
[0029] It should be noted that the modified polyamine ether is prepared by the following method: under the protection of nitrogen at 40℃, polyether amine D-230 is reacted with maleic anhydride at a molar ratio of 1:0.8 for 2h to obtain modified polyether amine 1# with an acid value of 20mgKOH / g.
[0030] It should be noted that the modified polyamine ether is prepared by the following method: polyether amine D-230 is reacted with maleic anhydride at a molar ratio of 1:0.9 at 45°C for 1.8h to obtain a modified polyether amine 2# with an acid value of 25mgKOH / g.
[0031] It should be noted that the modified polyamine ether is prepared by the following method: polyether amine D-230 is reacted with maleic anhydride at a molar ratio of 1:0.9 at 45°C for 1.8h to obtain a modified polyether amine 2# with an acid value of 25mgKOH / g.
[0032] It should be noted that the acetylacetone trinetal complex accelerator is an acetylacetone Zn / Al / La trinetal complex, and its preparation method comprises the following steps: acetylacetone with a concentration of 0.5mol / L is mixed with Zn(NO3)2, AlCl3 and La(NO3)3 at a molar ratio of 3:1:1:0.5, ethanol is used as the solvent, ammonia water is added dropwise to adjust the pH to 6.2, and after 3.5h of reaction, centrifugal separation is performed, and the acetylacetone Zn / Al / La trinetal complex with a particle size of 12-14nm is obtained after vacuum drying at 60°C for 8h.
[0033] It should be noted that a fast-drying high-adhesion modified curing agent is prepared by the following steps: 40 parts by weight of modified alicyclic amine 1# and 60 parts by weight of modified polyether amine 1# are slowly added to a reaction kettle under the condition of 28°C and stirring speed of 300r / min, and continuous stirring is carried out for 50min under nitrogen atmosphere to obtain a modified curing agent system; 6 parts by weight of acetylacetone Zn / Al / La trinetal complex is added to the above-mentioned modified curing agent system in three times with an interval of 5min each time, and stirring is continued for 25min to obtain modified curing agent 1#.
[0034] It should be noted that a fast-drying high-adhesion modified curing agent is prepared by the following steps: 40 parts by weight of modified alicyclic amine 1# and 60 parts by weight of modified polyether amine 1# are slowly added to a reaction kettle under the condition of 28°C and stirring speed of 300r / min, and continuous stirring is carried out for 50min under nitrogen atmosphere to obtain a modified curing agent system; 6 parts by weight of acetylacetone Zn / Al / La trinetal complex is added to the above-mentioned modified curing agent system in three times with an interval of 5min each time, and stirring is continued for 25min to obtain modified curing agent 1#.
[0035] It should be noted that a kind of fast-drying high-adhesion modified curing agent is prepared by the following steps: 50 parts by weight of modified alicyclic amine 3# is slowly added to the reaction kettle with 50 parts by weight of modified polyether amine 3#, under the condition of 32 ℃, stirring rate 250r / min, continuously stirring for 40min under nitrogen atmosphere, uniformly mixed to obtain modified curing agent system;5 parts by weight of acetylacetone Zn / Al / La three-metal complex is added to the above-mentioned modified curing agent system in 3 times, with an interval of 5min each time, continue to stir for 20min, to obtain modified curing agent 3#.
[0036] It should be noted that a modified curing agent is prepared by the following steps: 60 parts by weight of alicyclic amine H-1230 is slowly added to the reaction kettle with 30 parts by weight of polyether amine D-230, under the condition of 30 ℃, stirring rate 280r / min, continuously stirring for 45min under nitrogen atmosphere, uniformly mixed to obtain modified curing agent system;5 parts by weight of acetylacetone Zn / Al / La three-metal complex is added to the above-mentioned modified curing agent system in 3 times, with an interval of 5min each time, continue to stir for 22min, to obtain modified curing agent 4#.
[0037] It should be noted that a modified curing agent is prepared by the following steps: 40 parts by weight of modified alicyclic amine 1# is slowly added to the reaction kettle with 60 parts by weight of modified polyether amine 1#, under the condition of 28 ℃, stirring rate 300r / min, continuously stirring for 50min under nitrogen atmosphere, uniformly mixed to obtain modified curing agent system;6 parts by weight of acetylacetone Zn / Al / La three-metal complex is added to the above-mentioned modified curing agent system in 3 times, with an interval of 5min each time, continue to stir for 25min, to obtain modified curing agent 5#.
[0038] It should be noted that a modified curing agent is prepared by the following steps: 60 parts by weight of alicyclic amine H-1230 is slowly added to the reaction kettle with 30 parts by weight of polyether amine D-230, under the condition of 30 ℃, stirring rate 280r / min, continuously stirring for 45min under nitrogen atmosphere, uniformly mixed to obtain modified curing agent system;5 parts by weight of acetylacetone Zn / Al / La three-metal complex is added to the above-mentioned modified curing agent system in 3 times, with an interval of 5min each time, continue to stir for 22min, to obtain modified curing agent 4#.
[0039] It should be noted that a modified curing agent is prepared by the following steps: 40 parts by weight of modified alicyclic amine 1# and 60 parts by weight of modified polyether amine 1# are slowly added to a reaction kettle at 28°C and a stirring rate of 300 r / min, and stirring is continued for 50 min under a nitrogen atmosphere, and the mixture is uniformly mixed to obtain a modified curing agent system; 6 parts by weight of acetylacetone Zn / Al bimetallic complex is added to the above-mentioned modified curing agent system in 3 portions, with an interval of 5 min between each addition, and stirring is continued for 25 min to obtain modified curing agent 7#.
[0040] Example 1 A method for applying a fast-drying high-adhesion modified curing agent suitable for automobile parts, comprising the following steps: (1) Base pretreatment: 80-100 mesh white corundum sand is used to sandblast the surface of the steel plate base at a pressure of 0.5 MPa, and the steel plate is ultrasonically cleaned with acetone for 15 min to remove the oxide layer; a fiber laser with a wavelength of 1064 nm is used, with an energy density of 2.0 J / cm² and a pulse frequency of 16 kHz, and an etching path spacing of 0.8 mm, to form a gradient micro groove with alternating shallow grooves of 6-7 μm in depth and 12-14 μm in width and deep grooves of 13-14 μm in depth and 26-28 μm in width on the surface of the steel plate; the laser-etched base material is immersed in a composite etching solution of 5% sulfuric acid + 0.5% phosphoric acid + 0.1% sodium fluoride, and reacted at 45°C for 18 min, to form nanometer protrusions with a height of 80-100 nm and a diameter of 50-60 nm on the inner wall of the micro groove and the inter-groove area; the base material is rinsed with deionized water for 3 times, 2 min each time, and dried at 80°C for 30 min for standby; (2) Coating curing: modified curing agent 1# and epoxy resin E-51 are uniformly coated on the surface of the treated steel plate in a mass ratio of 1:5 using spraying / scratching, and the coating thickness is controlled at 80-90 μm, and cured in an environment of 23°C and a relative humidity of 45%.
[0041] Example 2 A method for applying a fast-drying high-adhesion modified curing agent suitable for automobile parts, comprising the following steps: (1) Base substrate pretreatment: 80-100 mesh white corundum sand is used to sand blast the surface of the steel plate substrate under a pressure of 0.5 MPa, and the surface is ultrasonically cleaned with acetone for 15 min to remove the oxide layer; a fiber laser with a wavelength of 1064 nm is used, the energy density is set to 2.0 J / cm2, the pulse frequency is 16 kHz, and the etching path spacing is 0.8 mm, to form gradient microgrooves with alternating shallow grooves with a depth of 6-7 μm and a width of 12-14 μm and deep grooves with a depth of 13-14 μm and a width of 26-28 μm on the surface of the steel plate; the laser-etched substrate is immersed in a composite etching solution of 5% sulfuric acid + 0.5% phosphoric acid + 0.1% sodium fluoride, and reacted at 48°C for 15 min to form nanoprotrusions with a height of 100-120 nm and a diameter of 60-70 nm on the inner wall of the microgrooves and the inter-groove area; the substrate is rinsed with deionized water for 3 times, each time for 2 min, and dried at 80°C for 30 min for standby; (2) Coating curing: the modified curing agent 2# is uniformly coated on the surface of the treated steel plate in a mass ratio of 1:4 with the paint by spraying, and the coating thickness is controlled at 90-100 μm, and the coating is cured in an environment of 24°C and a relative humidity of 50%.
[0042] Example 3 A method for applying a fast-drying high-adhesion modified curing agent suitable for automobile parts, comprising the following steps: (1) Base substrate pretreatment: 80-100 mesh white corundum sand is used to sand blast the surface of the steel plate substrate under a pressure of 0.5 MPa, and the surface is ultrasonically cleaned with acetone for 15 min to remove the oxide layer; a fiber laser with a wavelength of 1064 nm is used, the energy density is set to 2.0 J / cm2, the pulse frequency is 16 kHz, and the etching path spacing is 0.8 mm, to form gradient microgrooves with alternating shallow grooves with a depth of 6-7 μm and a width of 12-14 μm and deep grooves with a depth of 13-14 μm and a width of 26-28 μm on the surface of the steel plate; the laser-etched substrate is immersed in a composite etching solution of 5% sulfuric acid + 0.5% phosphoric acid + 0.1% sodium fluoride, and reacted at 50°C for 12 min to form nanoprotrusions with a height of 120-150 nm and a diameter of 70-80 nm on the inner wall of the microgrooves and the inter-groove area; the substrate is rinsed with deionized water for 3 times, each time for 2 min, and dried at 80°C for 30 min for standby; (2) Coating curing: the modified curing agent 3# is uniformly coated on the surface of the treated steel plate in a mass ratio of 1:4 with the paint by spraying / doctoring, and the coating thickness is controlled at 100-120 μm, and the coating is cured in an environment of 25°C and a relative humidity of 55%.
[0043] Example 4 A method for applying a fast-drying high-adhesion modified curing agent suitable for electronic component packaging, comprising the following steps: (1) substrate pretreatment: 100 mesh silicon carbide sand, 0.4 MPa pressure on the surface of alumina ceramic substrate sandblasting treatment, ultrasonic cleaning with acetone 10 min, remove the oxide layer; using wavelength 1064 nm fiber laser, set the energy density 1.5 J / cm2, pulse frequency 14 kHz, etching path spacing 0.6 mm, on the surface of the steel plate formed depth 5-6 μm, width 10-12 μm shallow groove and depth 12-13 μm, width 25-27 μm deep groove gradient micron groove alternately; the laser etched substrate immersed in 5% sulfuric acid + 0.5% phosphoric acid + 0.1% sodium fluoride composite etching liquid, 45 ℃ reaction 18 min, in the micron groove wall and groove area generated height 80-100 nm, diameter 50-60 nm nano convex; (2) coating curing: modified curing agent 1# and polyurethane prepolymer by mass ratio 1:5 using mixed preparation of polyurethane potting adhesive, using dispensing machine polyurethane potting adhesive uniform coating on the surface of the treated ceramic substrate, coating thickness control in 110-120 μm, in 23 ℃, relative humidity 45% environment curing.
[0044] Example 5 A method for applying a fast-drying high-adhesion modified curing agent suitable for electronic component packaging, comprising the following steps: (1) substrate pretreatment: 100 mesh silicon carbide sand, 0.4 MPa pressure on the surface of alumina ceramic substrate sandblasting treatment, ultrasonic cleaning with acetone 10 min, remove the oxide layer; using wavelength 1064 nm fiber laser, set the energy density 1.5 J / cm2, pulse frequency 14 kHz, etching path spacing 0.6 mm, on the surface of the steel plate formed depth 5-6 μm, width 10-12 μm shallow groove and depth 12-13 μm, width 25-27 μm deep groove gradient micron groove alternately; the laser etched substrate immersed in 5% sulfuric acid + 0.5% phosphoric acid + 0.1% sodium fluoride composite etching liquid, 48 ℃ reaction 15 min, in the micron groove wall and groove area generated height 100-120 nm, diameter 60-70 nm nano convex; after washing the substrate with deionized water, drying at 75 ℃ for 25 min for standby; (2) coating curing: modified curing agent 2# and polyurethane prepolymer by mass ratio 1:5 using mixed preparation of polyurethane potting adhesive, using dispensing machine polyurethane potting adhesive uniform coating on the surface of the treated ceramic substrate, coating thickness control in 110-120 μm, in 24 ℃, relative humidity 50% environment curing.
[0045] Example 6 A method for applying a fast-drying high-adhesion modified curing agent suitable for electronic component packaging, comprising the following steps: (1) Base substrate pretreatment: 100 mesh silicon carbide sand is used to sandblast the surface of the alumina ceramic substrate under a pressure of 0.4 MPa, and the substrate is ultrasonically cleaned with acetone for 10 min to remove the oxide layer; a fiber laser with a wavelength of 1064 nm is used, the energy density is set to 1.5 J / cm², the pulse frequency is 14 kHz, and the etching path spacing is 0.6 mm, to form gradient microgrooves with alternating shallow grooves of a depth of 5-6 μm and a width of 10-12 μm and deep grooves of a depth of 12-13 μm and a width of 25-27 μm on the surface of the steel plate; the laser-etched substrate is immersed in a composite etching solution of 5% sulfuric acid + 0.5% phosphoric acid + 0.1% sodium fluoride, and reacted at 50°C for 12 min to form nanoprotrusions with a height of 120-150 nm and a diameter of 70-80 nm on the inner wall of the microgrooves and the area between the grooves; after the substrate is rinsed with deionized water, it is dried at 75°C for 25 min for standby use; (2) Coating curing: polyurethane pouring sealant is prepared by mixing modified curing agent 3# and polyurethane prepolymer at a mass ratio of 1:4, and the polyurethane pouring sealant is uniformly coated on the surface of the treated ceramic substrate using a dispensing machine, with a coating thickness controlled at 110-120 μm, and cured in an environment of 25°C and a relative humidity of 55%.
[0046] Comparative Example 1 Compared with Example 2, modified curing agent 2 is replaced with modified curing agent 4#, and the remaining steps are the same as those of Example 2.
[0047] Comparative Example 2 Compared with Example 2, modified curing agent 2 is replaced with modified curing agent 6#, and the remaining steps are the same as those of Example 2.
[0048] Comparative Example 3 Compared with Example 4, modified curing agent 1# is replaced with modified curing agent 5#, and the remaining steps are the same as those of Example 4.
[0049] Comparative Example 4 Compared with Example 4, modified curing agent 1# is replaced with modified curing agent 7#, and the remaining steps are the same as those of Example 4.
[0050] Comparative Example 5 A method for applying a fast-drying high-adhesion modified curing agent suitable for automobile parts, comprising the following steps: (1) Base substrate pretreatment: 80-100 mesh white corundum sand is used to sandblast the surface of the steel plate substrate under a pressure of 0.5 MPa, and the substrate is ultrasonically cleaned with acetone for 15 min to remove the oxide layer, then the substrate is immersed in the etching solution until the target roughness is reached, and then it is thoroughly washed with water and dried; (2) Coating curing: The modified curing agent 6# and the coating are evenly coated on the surface of the treated steel plate by spraying at a mass ratio of 1:4. The coating thickness is controlled at 90-100μm and cured at 24℃ and 50% relative humidity.
[0051] Comparative Example 6 An application method for a fast-drying, high-adhesion modified curing agent suitable for electronic component encapsulation includes the following steps: (1) Substrate pretreatment: The surface of the alumina ceramic substrate is ultrasonically cleaned and dried, and lightly polished to increase the etching uniformity. The substrate is then immersed in the etching solution until the target roughness is achieved, and then thoroughly washed with water and dried. (2) Coating curing: The modified curing agent 7# and polyurethane prepolymer are mixed at a mass ratio of 1:5 to prepare polyurethane potting compound. The polyurethane potting compound is uniformly coated on the surface of the treated ceramic substrate using a dispensing machine. The coating thickness is controlled at 110-120μm and cured at 23℃ and 45% relative humidity.
[0052] Test The application performance of the coating prepared above was tested, and the specific test methods are as follows: Curing efficiency test: The surface drying time and actual drying time of the coating are monitored by differential scanning calorimetry (DSC). The time when the weight loss rate of the coating reaches 0.8%-0.9% is recorded as the surface drying time; the time when the coating reaches a pencil hardness of 2H or a Shore hardness of 85D is recorded as the actual drying time.
[0053] Mechanical property testing: Tensile strength testing was conducted according to national standard GB / T5210, and flexural strength testing was conducted according to national standard GB / T6741-2007; Coating internal stress value testing: First, the initial curvature of the uncoated substrate was measured, then the coating was applied to the substrate and cured; the curvature of the substrate after coating was measured; the stress value was calculated according to the Stoney formula, the calculation formula is as follows:
[0054] Adhesion: The adhesion level is tested by cross-cut test; weather resistance and shock resistance tests are conducted according to different application scenarios. The weather resistance test is carried out by artificial accelerated aging test of the coating for 500 hours, namely ultraviolet irradiation and condensation cycle, to test the yellowing index and whether there is chalking phenomenon; the shock resistance test is carried out by 120 impact tests with a 500g steel ball from a height of 1.2m to observe whether there is peeling phenomenon of the coating.
[0055] Corrosion resistance: The corrosion resistance of the substrate was tested in acidic, alkaline and salt environments. The specific test steps were as follows: The substrate was immersed in 5% sulfuric acid solution, 5% sodium hydroxide solution and 5% sodium chloride solution for 72h, 72h and 168h respectively. After immersion, the coating surface was observed for rust, blistering, swelling or discoloration, and the adhesion retention rate of the coating was tested.
[0056] The substrates treated in Examples 1-3, Comparative Examples 1, 2, and 5 were tested for curing efficiency, mechanical properties, adhesion, weather resistance, and corrosion resistance. The specific test results are shown in Table 1. As can be seen from the data in Table 1, compared with Comparative Examples 1-2 and 5, the coatings in Examples 1-3 had relatively lower surface drying time and complete drying time, and significantly improved mechanical properties. The stress value was reduced to below 5 MPa, with no cracking. Tensile strength increased by 35-45%, and flexural strength increased by 30-40%. This indicates that the present invention uses modified cycloaliphatic amines and modified polyether amines as raw materials for the modified curing agent, which, in synergy with the trimetallic accelerator, can significantly improve the film-forming quality and mechanical properties of the coating. Weather resistance was also tested. Tests showed that the yellowing index of the coatings prepared in Examples 1-3 of this invention was only 1.8-2.2, which is more than 40% lower than that of Comparative Examples 1-2 and Comparative Example 5. When the coatings prepared in Examples 1-3 were immersed in 5% sodium chloride solution for 168 hours, the adhesion retention rate of the coatings was more than 95%, which is more than 20% higher than that of the coatings prepared in Comparative Examples 1, 2, and 5. Moreover, the coatings were free of rust and blistering, and the corrosion current density was reduced by 60% compared with the traditional system, thus meeting the long-term corrosion protection requirements of automotive parts.
[0057] Table 1 Performance test results of different coatings applicable to automotive parts
[0058] The substrates treated in Examples 4-6, Comparative Examples 3, 4, and 6 were tested for curing efficiency, tensile shear strength, seismic resistance, and corrosion resistance. The specific test results are shown in Table 2. As shown in Table 2, compared with Comparative Examples 3-4 and 6, the surface drying time and actual drying time of the coatings in Examples 4-6 were relatively low, and their tensile shear strength was increased by more than 45%. This indicates that the modified cycloaliphatic amine and modified polyether amine used as raw materials for the modified curing agent, in synergy with the trimetallic accelerator, can significantly improve the film quality and mechanical properties of the coating. Furthermore, a shock resistance test was conducted. The substrates prepared in Examples 4-6 of this invention did not peel off after 120 impact tests, meeting the vibration resistance requirements of electronic component packaging. The coatings prepared in Examples 4-6 were immersed in 5% sulfuric acid and 5% sodium hydroxide solutions for 72 hours, respectively. The adhesion retention rate of the coatings was above 95%, which is more than 20% higher than that of the coatings prepared in Comparative Examples 3, 4, and 6. The coatings also swelled and discolored, making them suitable for complex operating environments of electronic components. The electrical insulation properties of the coatings in Examples 4-6 were also tested, with a resistivity of 1.2 × 10⁻⁶. 14 Ω・cm, dielectric loss tangent (1kHz) 0.002, conforming to the insulation standard for electronic components.
[0059] Table 2 Performance test results of different coatings suitable for electronic component packaging
[0060] In summary, the modified curing agent of this invention is a synergistic combination of a modified two-component alicyclic amine and a trimetallic accelerator, while simultaneously employing a gradient micro / nano structure design for the substrate. Through an integrated approach of chemical structure modification, multi-metal complexation synergy, and functionalized micro / nano structure design of the substrate, it shortens curing time, enhances the long-term adhesion stability between the coating and the substrate, and improves the coating's weather resistance and chemical resistance. This meets the technical requirements of high-end industrial coating applications such as automotive parts, marine engineering equipment, and electronic component packaging, which demand fast drying, high adhesion, and high stability in cured coatings.
[0061] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention.
Claims
1. A fast-drying, high-adhesion modified curing agent, characterized in that, It includes the following raw materials in parts by weight: 40-60 parts of modified alicyclic amine, 40-60 parts of modified polyurethane ether, and 4-6 parts of acetylacetone trimetallic complex accelerator.
2. The fast-drying, high-adhesion modified curing agent according to claim 1, characterized in that, The modified alicyclic amine was prepared by the following method: under nitrogen protection at 60-70℃, the alicyclic amine was reacted with propylene oxide at a molar ratio of 1:1.2-1.5 for 2-3 hours to obtain a modified alicyclic amine with a molecular weight of 800-1000.
3. The fast-drying, high-adhesion modified curing agent according to claim 1, characterized in that, The modified polyamine ether is prepared by the following method: at 40-50℃, polyetheramine and maleic anhydride are reacted at a molar ratio of 1:0.8-1.0 for 1.5-2 hours to obtain a modified polyetheramine with an acid value of 20-30 mgKOH / g.
4. The fast-drying, high-adhesion modified curing agent according to claim 1, characterized in that, The acetylacetone trimetallic complex accelerator is an acetylacetone Zn / Al / La trimetallic complex.
5. The fast-drying, high-adhesion modified curing agent according to claim 4, characterized in that, The acetylacetone Zn / Al / La trimetallic complex was prepared by the following method: acetylacetone at a concentration of 0.5 mol / L was mixed with Zn(NO3)2, AlCl3, and La(NO3)3 in a molar ratio of 3:1:1:0.
5. Ethanol was used as the solvent, and ammonia was added dropwise to adjust the pH to 6.0-6.
5. After reacting for 3-4 hours, the mixture was centrifuged and vacuum dried for 8 hours to obtain an acetylacetone Zn / Al / La trimetallic complex with a particle size of 10-15 nm.
6. A method for preparing the fast-drying, high-adhesion modified curing agent according to any one of claims 1-5, characterized in that, The process includes the following steps: At 28-32℃ and a stirring rate of 250-300 r / min, the modified alicyclic amine and the modified polyether amine are slowly added to the reactor in parts by weight, and stirred continuously for 40-50 min under a nitrogen atmosphere to obtain a modified curing agent system; acetylacetone Zn / Al / La trimetallic complex is added to the modified curing agent system in 2-3 portions, with an interval of 5 min between each addition, and stirring is continued for 20-25 min to obtain the modified curing agent.
7. The application method of the fast-drying, high-adhesion modified curing agent according to any one of claims 1-6, characterized in that, For use as a protective coating on a substrate, the specific steps include: (1) Substrate pretreatment: The substrate surface is sandblasted with 80-100 mesh white corundum sand under a pressure of 0.5 MPa, and ultrasonically cleaned with acetone for 15 min to remove the oxide layer; a gradient micron groove with alternating shallow and deep grooves is etched on the substrate surface using a fiber laser; the laser-etched substrate is immersed in a composite etching solution and reacted at 45-50℃ for 12-18 min to generate nano-protrusions with a height of 80-150 nm and a diameter of 50-80 nm on the inner wall of the micron groove and in the groove area; the substrate is rinsed with deionized water and then dried at 75-80℃ for later use. (2) Coating curing: The modified curing agent and the coating are uniformly coated on the surface of the treated substrate by spraying / scraping at a mass ratio of 1:4-1:
5. The coating thickness is controlled at 80-120μm and cured at 23-25℃ and 45%-55% relative humidity.
8. The application method of the fast-drying, high-adhesion modified curing agent according to claim 7, characterized in that, The shallow groove in step (1) has a depth of 5-8 μm and a width of 10-15 μm; the deep groove has a depth of 12-15 μm and a width of 25-30 μm.
9. The application method of the fast-drying, high-adhesion modified curing agent according to claim 7, characterized in that, The composite etching solution in step (1) consists of 5% sulfuric acid, 0.5% phosphoric acid, and 0.1% fluoride.