Preparation method and application of multifunctional water-based primer

Abstract

The application discloses a preparation method of a multifunctional water-based primer, and the primer comprises the following components: 40-55 parts of water-based acrylic resin, 20-30 parts of water-based silicone resin, 5-10 parts of deionized water, 1-5 parts of solvent, 8-12 parts of amino resin, 0.3-1 part of catalyst, 0.3-1.5 parts of wetting agent, 0.3-1.5 parts of leveling agent, 0.3-1 part of defoaming agent and 0.5-1.5 parts of water-based thickening agent; and the preparation method comprises the following steps: mixing the deionized water and the solvent to obtain a first mixed solution; mixing the water-based acrylic resin and the water-based silicone resin to obtain a second mixed solution; mixing the first mixed solution and the second mixed solution to obtain a third mixed solution; mixing the amino resin and the third mixed solution to obtain a fourth mixed solution; and mixing the catalyst, the wetting agent, the leveling agent, the defoaming agent, the water-based thickening agent and the fourth mixed solution and filtering. The multifunctional water-based primer provided by the application solves the problems that different coating materials are needed for different metal substrates, and the problems that the coating needs to simultaneously meet the requirements of good bending resistance, impact resistance, high-temperature resistance and cycle resistance, and the research and development cost and the downstream application cost are saved.

Description

Technical Field

[0001] This invention relates to the field of coating technology, and in particular to a method for preparing and applying a multifunctional water-based primer. Background Technology

[0002] Currently, with the rapid iteration and upgrading of products in the consumer electronics sector, the substrate and functional requirements of these products are constantly changing. This constant evolution of substrates necessitates continuous iteration and upgrading of coating materials. However, this continuous iteration of coating products requires significant investment in research and development and application costs. The market urgently needs a multifunctional coating material that can simultaneously meet the requirements for protection and decoration on various metal substrates. This material should not only satisfy the adhesion requirements of different metal substrates but also possess good wear resistance, withstand various environmental tests, and high-temperature resistance. Summary of the Invention

[0003] To address the technical problems in the background art, this invention provides a method for preparing and applying a multifunctional water-based primer. The specific technical solution is as follows:

[0004] A method for preparing a multifunctional water-based primer, the multifunctional water-based primer comprising the following components by weight: 40-55 parts water-based acrylic resin, 20-30 parts water-based silicone resin, 5-10 parts deionized water, 1-5 parts solvent, 8-12 parts amino resin, 0.3-1 part catalyst, 0.3-1.5 parts wetting agent, 0.3-1.5 parts leveling agent, 0.3-1 part defoamer, and 0.5-1.5 parts water-based thickener. The specific steps of preparing the multifunctional water-based primer are as follows:

[0005] Step 1: Mix deionized water and solvent, and disperse evenly to obtain the first mixture;

[0006] Step 2: Mix the water-based acrylic resin and the water-based silicone resin, and disperse them evenly to obtain the second mixture;

[0007] Step 3: Mix the first mixture and the second mixture, and disperse them evenly to obtain the third mixture;

[0008] Step 4: Mix the amino resin and the third mixture, and disperse them evenly to obtain the fourth mixture;

[0009] Step 5: Mix and disperse the catalyst, wetting agent, leveling agent, defoamer, water-based thickener and the fourth mixture evenly, filter to obtain the first filtrate, which is the multifunctional water-based primer.

[0010] Preferably, the multifunctional water-based primer further comprises 2 to 6 parts of matting powder, which is added to the fourth mixture in step 5.

[0011] Preferably,

[0012] In step 3, the first mixture and the second mixture are mixed by slowly adding the first mixture to the second mixture.

[0013] In step 4, the amino resin and the third mixture are mixed by slowly adding the amino resin to the third mixture.

[0014] Preferably, the first mixture and the amino resin are added dropwise.

[0015] Preferably, the dispersion method is stirring dispersion.

[0016] Preferably,

[0017] The waterborne acrylic resin is a carboxyl-modified waterborne acrylic resin and / or a waterborne acrylic resin modified with phosphate ester groups.

[0018] The aqueous organosilicon resin is an aqueous organosilicon modified emulsion;

[0019] The amino resin is one or more of fully methylated amino resin, mixed etherified amino resin, and partially etherified high imino resin;

[0020] The catalyst is a blocked acid catalyst, and the deblocking temperature of the blocked acid catalyst is 80~130℃;

[0021] The solvent is one or more of diethylene glycol butyl ether, ethylene glycol butyl ether, dipropylene glycol butyl ether, and propylene glycol butyl ether;

[0022] The wetting agent is one or more of BYK 349, BYK 346, TEGO® Wet 245, and TEGO® Wet 270;

[0023] The leveling agent is one or more of BYK 333, BYK 3760, TEGO® Glide 406, and TEGO® Glide 410;

[0024] The defoamer is one or more of BYK 3481, BYK 024, TEGO® Foamex 810, and TEGO® Foamex 825;

[0025] The matting agent is one or more of Tosoh E-220A, Tosoh E-1011, Grace C803, Grace SYLOID 7000, and Evonik ACEMATT TS100;

[0026] The aqueous thickener is one or more of TEGO® ViscoPlus 3030, TEGO® ViscoPlus 3060, RHEOLATE 299, and RHEOLATE FX 1010.

[0027] Preferably, the preparation method of the phosphate ester group-modified waterborne acrylic resin specifically includes the following steps:

[0028] Step 10: Mix acrylate, phosphate ester and alcohol ether solvent in a mass ratio of 1:(0.8~1):(8~10) and disperse evenly. Heat to 100℃ to obtain the process solution.

[0029] Step 20: Add the initiator according to the mass ratio Add 1:(35~40) to the process solution and stir to disperse evenly;

[0030] Step 30: Cool down to 50~60℃, then add an alkaline regulator to adjust the pH to 7.5~8.5, and after uniform dispersion, the waterborne acrylic resin modified with phosphate ester groups is obtained.

[0031] The present invention also provides an application of a multifunctional water-based primer, wherein the multifunctional water-based primer prepared by any of the preparation methods described above is coated onto a metal substrate to form a paint film.

[0032] Preferably, the metal substrate is made of aluminum alloy, magnesium alloy, stainless steel, iron, zinc alloy, copper, or nickel.

[0033] Preferably, the process of coating the metal substrate to form a paint film specifically includes the following steps:

[0034] Step 100: Mix the multifunctional water-based primer and deionized water, and disperse them evenly to obtain a dispersion;

[0035] Step 200: Filter the dispersion through a 150-300 mesh filter cloth to obtain a second filtrate;

[0036] Step 300: Spray the second filtrate onto the metal substrate;

[0037] Step 400: Pre-bake the sprayed metal substrate at 60~80℃ for 5~15 minutes, then adjust the temperature to 140~170℃ and bake for 25~35 minutes.

[0038] The multifunctional water-based primer prepared by the method provided in this invention solves the problem of requiring different coating materials for different metal substrates, as well as the issue of coatings needing to simultaneously meet good bending resistance, impact resistance, high temperature resistance, and environmental testing resistance. By using only one coating material to meet the coating protection and decorative functions of more than 90% of metal substrates on the market, it saves R&D costs and downstream application costs. Detailed Implementation

[0039] To enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be described in detail below. The description in this part is only exemplary and explanatory, and should not be used to limit the scope of protection of the present invention in any way.

[0040] This embodiment provides a method for preparing a multifunctional water-based primer. The multifunctional water-based primer comprises the following components: by weight, 40-55 parts of water-based acrylic resin, 20-30 parts of water-based silicone resin, 5-10 parts of deionized water, 1-5 parts of solvent, 8-12 parts of amino resin, 0.3-1 part of catalyst, 0.3-1.5 parts of wetting agent, 0.3-1.5 parts of leveling agent, 0.3-1 part of defoamer, and 0.5-1.5 parts of water-based thickener. The specific steps of preparing the multifunctional water-based primer are as follows:

[0041] Step 1: Mix deionized water and solvent, and disperse evenly to obtain the first mixture.

[0042] Step 2: Mix the water-based acrylic resin and water-based silicone resin and disperse them evenly to obtain the second mixture.

[0043] Step 3: Mix the first mixture and the second mixture, and disperse them evenly to obtain the third mixture.

[0044] Step 4: Mix the amino resin and the third mixture, and disperse them evenly to obtain the fourth mixture.

[0045] Step 5: Mix and disperse the catalyst, wetting agent, leveling agent, defoamer, water-based thickener and the fourth mixture evenly, filter to obtain the first filtrate, which is a multifunctional water-based primer.

[0046] Water-based baking paint has a wide range of applications on metal substrates in the 3C industry. In the 3C field, water-based acrylic resin is typically used as the main resin for metal baking paint. Baking paint prepared with water-based acrylic resin as the main resin generally exhibits good adhesion to metal substrates, as well as good impact and bending resistance. However, when simulated high-temperature tests (300℃ and above), adhesion deteriorates and discoloration occurs. Water-based organic resins, on the other hand, have good high-temperature resistance and aging resistance. Combining them with water-based acrylic resin can improve the high-temperature resistance and aging resistance of the paint film. Baking paint prepared by combining the two in an appropriate ratio combines the advantages of both resins. Adding a suitable proportion of amino resin further enhances the paint film's flexibility, high-temperature resistance, and aging resistance. Compared to water-based acrylic resins, water-based silicone resins, after hydrolysis and curing, can form stronger chemical bonds with the metal substrate surface, giving the paint film better adhesion strength and further enhancing the water-boiling adhesion between the paint film and the metal substrate. This water-based baking paint exhibits good water resistance on various metal substrates, including aluminum alloys, magnesium alloys, various types of stainless steel, iron, zinc alloys, copper, and nickel, effectively solving adhesion problems on multiple substrates. The prepared paint can be used on a variety of metal substrates, and the cured film possesses excellent performance, making it promising for widespread application in the 3C and industrial sectors.

[0047] The multifunctional water-based primer prepared by the method provided in this embodiment solves the problem of requiring different coating materials for different metal substrates, as well as the problem of coatings needing to simultaneously meet good bending resistance, impact resistance, high temperature resistance, and environmental testing resistance. By using only one coating material to meet the coating protection and decorative functions of more than 90% of metal substrates on the market, it saves R&D costs and downstream application costs.

[0048] Furthermore, the multifunctional water-based primer also includes 2 to 6 parts of matting agent, which is added to the fourth mixture in step 5.

[0049] Furthermore, in step 3, the mixing method of the first mixture and the second mixture is as follows: the first mixture is slowly added to the second mixture.

[0050] In step 4, the amino resin and the third mixture are mixed by slowly adding the amino resin to the third mixture.

[0051] Furthermore, the first mixture and the amino resin are added dropwise.

[0052] Furthermore, the dispersion method is stirring dispersion.

[0053] Furthermore, the waterborne acrylic resin is a carboxyl-modified waterborne acrylic resin and / or a waterborne acrylic resin modified with phosphate ester groups.

[0054] The waterborne organosilicon resin is a waterborne organosilicon modified emulsion.

[0055] The amino resin is one or more of the following: fully methylated amino resin, mixed etherified amino resin, and partially etherified high-imino resin.

[0056] The catalyst is a blocked acid catalyst, and the deblocking temperature of the blocked acid catalyst is 80~130℃.

[0057] The solvent is one or more of diethylene glycol butyl ether, ethylene glycol butyl ether, dipropylene glycol butyl ether, and propylene glycol butyl ether.

[0058] The wetting agent is one or more of BYK 349, BYK 346, TEGO® Wet 245, and TEGO® Wet 270.

[0059] The leveling agent is one or more of BYK 333, BYK 3760, TEGO® Glide 406, and TEGO® Glide 410.

[0060] The defoamer is one or more of BYK 3481, BYK 024, TEGO® Foamex 810, and TEGO® Foamex 825.

[0061] The matting agent is one or more of the following: Tosoh E-220A, Tosoh E-1011, Grace C803, Grace SYLOID 7000, and Evonik ACEMATT TS100.

[0062] The water-based thickener is one or more of TEGO® ViscoPlus 3030, TEGO® ViscoPlus 3060, RHEOLATE 299, and RHEOLATE FX 1010.

[0063] Furthermore, the preparation method of the phosphate ester group modified waterborne acrylic resin specifically includes the following steps:

[0064] Step 10: Mix acrylate, phosphate ester and alcohol ether solvent in a mass ratio of 1:(0.8~1):(8~10) and disperse evenly. Heat to 100℃ to obtain the process solution.

[0065] Step 20: Add the initiator according to the mass ratio =1:(35~40) Add to the process solution and stir to disperse evenly.

[0066] Step 30: Cool to 50~60℃, then add an alkaline regulator to adjust the pH to 7.5~8.5, and after uniform dispersion, obtain a waterborne acrylic resin modified with phosphate ester groups.

[0067] This embodiment also provides an application of a multifunctional water-based primer, wherein the multifunctional water-based primer prepared by any of the above preparation methods is coated onto a metal substrate to form a paint film.

[0068] Furthermore, the metal substrate can be made of aluminum alloy, magnesium alloy, stainless steel, iron, zinc alloy, copper, or nickel.

[0069] Furthermore, the process of coating a metal substrate to form a paint film specifically includes the following steps:

[0070] Step 100: Mix the multi-functional water-based primer and deionized water, and disperse them evenly to obtain a dispersion.

[0071] Step 200: Filter the dispersion through a 150-300 mesh filter cloth to obtain the second filtrate.

[0072] Step 300: Spray the second filtrate onto the metal substrate.

[0073] Step 400: Pre-bake the sprayed metal substrate at 60~80℃ for 5~15 minutes, then adjust the temperature to 140~170℃ and bake for 25~35 minutes.

[0074] Furthermore, the components of the multifunctional water-based primer can be formulated in the specific proportions shown in the table below:

[0075]

[0076] The following provides the component ratios of several specific embodiments. Each embodiment is prepared according to the following steps:

[0077] Step 1: Mix the weighed deionized water and solvent to prepare the first mixture.

[0078] Step 2: Mix the weighed water-based acrylic resin and water-based silicone resin to prepare a second mixture.

[0079] Step 3: Slowly add the first mixture to the weighed second mixture and mix to prepare the third mixture.

[0080] Step 4: Slowly add the weighed amino resin to the third mixture, and after mixing, prepare the fourth mixture.

[0081] Step 5: Add the weighed catalyst, wetting agent, leveling agent, defoamer, matting agent and water-based thickener to the fourth mixture, mix them, and then prepare the fifth mixture. After filtration, the multifunctional water-based primer coating is obtained.

[0082] The group allocation examples for each group of embodiments are shown in the table below:

[0083]

[0084] The multifunctional water-based primers prepared in each group of examples were applied to metal substrates according to the following steps:

[0085] The prepared multifunctional water-based primer was mixed with 20% deionized water according to the weight ratio, then filtered through a 200-mesh filter cloth, and sprayed onto a metal substrate through an automatic spray gun. The sprayed product was pre-baked at 75°C for 15 minutes, and then transferred to 170°C for 35 minutes.

[0086] Results of physical property tests on coatings in Examples 1-5 and Comparative Examples 1-3:

[0087]

[0088] As can be seen from Examples 1 to 5 in the table above, when waterborne acrylic resin, waterborne silicone resin and amino resin are mixed in an appropriate ratio, the resulting paint film has good conventional adhesion and boiling water adhesion on different metal substrates. At the same time, the paint film has good bending resistance, impact resistance, wear resistance, high temperature resistance, aging resistance, high temperature and high humidity resistance, cold and heat cycle resistance and high pencil hardness.

[0089] As shown in Comparative Example 1 and Examples 1-5, when acrylic resin and amino resin are used alone, the resulting paint film exhibits decreased resistance to bending, impact, and high temperatures. Simultaneously, its resistance to high temperature and humidity, as well as its resistance to thermal cycling, decreases. This is mainly because the acrylic resin molecular chain has a certain rigidity, exhibiting brittleness under external stress. Since waterborne acrylic polymers do not have good temperature resistance, generally above 300℃, the polymer chains undergo oxidative degradation, causing the paint film to gradually yellow. However, as shown in Comparative Example 2 and Comparative Example 1, waterborne silicone resins possess better high-temperature resistance. This is due to the protective effect of inorganic siloxanes in the molecular chain segments on nearby molecular chain segments, resulting in better resistance to high-temperature degradation. It can withstand temperatures above 300℃ without yellowing. When used in combination with resins prone to yellowing, it can alleviate yellowing under high-temperature conditions and reduce adhesion after high-temperature baking, demonstrating better high-temperature resistance. The free rotation of silicon-oxygen bonds in organosilicon molecular chains endows the molecular chains with good flexibility, resulting in coatings with excellent bending and impact resistance. However, these coatings also suffer from poor abrasion resistance and low hardness. When waterborne acrylic resins are used alone, their resistance to thermal cycling decreases because acrylic resins typically have a high Tg point. Under thermal shock cycles, the internal stress of the coating continuously changes, leading to decreased adhesion to the substrate and blistering. In contrast, organosilicon resins, due to the free rotation of their siloxane segments, can mitigate the drastic changes in internal stress under high and low temperature shocks, ensuring good adhesion between the coating and the substrate. Therefore, coatings prepared by combining the properties of both resins can possess the excellent characteristics of both, resulting in coatings with superior performance.

[0090] As shown in Comparative Example 3 and Examples 4-5, when the amount of amino resin in the system exceeds a certain range, the paint film becomes harder, and its flexibility, impact resistance, adhesion, and resistance to high temperature and humidity, as well as its resistance to thermal cycling, decrease. This is attributed to the self-crosslinking tendency of amino resin under high temperature conditions, leading to excessive self-crosslinking of the amino resin in the paint film, making the paint film brittle, reducing its flexibility and impact resistance, and consequently worsening its adhesion. It is necessary to combine it with appropriate resins in a certain proportion to form a paint film with better performance.

[0091] As can be seen from Examples 1-5 and Comparative Examples 1-3 above, when waterborne acrylic resin and waterborne silicone resin are mixed in a certain proportion in the system, and an appropriate proportion of amino resin is added, the prepared coating film not only has good conventional adhesion on various metal substrates, but also has good boiling water resistance. The coating film also has good flexibility, wear resistance and environmental resistance, and has a wide range of applications.

[0092] Baking varnishes made primarily of waterborne acrylic resins generally exhibit good adhesion to metal substrates, along with good impact and bending resistance. In contrast, baking varnishes made from waterborne silicone resins demonstrate superior high-temperature resistance and aging resistance. Research has shown that combining these two resins in appropriate proportions creates a baking varnish that combines the advantages of both. The resulting film possesses not only good flexibility but also excellent high-temperature and aging resistance. Bending and impact resistance tests on the cured film showed that it did not crack after bending 180 degrees or undergoing a 50 kg·cm impact test. Further high-temperature testing revealed that the film remained unchanged after 0.5 hours of baking at 300℃. Compared to waterborne acrylic resins, waterborne silicone resins, after hydrolysis and curing, form stronger chemical bonds with the metal substrate surface, resulting in better adhesion and further enhancing the water-resistant adhesion between the film and the metal substrate. This water-based baking paint exhibits good water resistance on various metal substrates, including aluminum alloys, magnesium alloys, various types of stainless steel, iron, zinc alloys, copper, and nickel, effectively solving adhesion problems on multiple substrates. The prepared paint can be used on a variety of metal substrates, and the cured film possesses excellent performance, making it promising for widespread application in the 3C and industrial sectors.

[0093] This article uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the technical scope disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be within the scope of protection of the present invention.

Claims

1. A method for preparing a multifunctional waterborne primer, characterized by, The multifunctional water-based primer is prepared from the following components: 40-55 parts by weight of water-based acrylic resin, 20-30 parts by weight of water-based silicone resin, 5-10 parts by weight of deionized water, 1-5 parts by weight of solvent, 8-12 parts by weight of amino resin, 0.3-1 part by weight of catalyst, 0.3-1.5 parts by weight of wetting agent, 0.3-1.5 parts by weight of leveling agent, 0.3-1 part by weight of defoaming agent, 0.5-1.5 parts by weight of water-based thickening agent, and 2-6 parts by weight of flatting powder. S1: mixing deionized water and solvent, and uniformly dispersing to obtain a first mixture; S2: mixing water-based acrylic resin and water-based silicone resin, and uniformly dispersing to obtain a second mixture; S3: mixing the first mixture and the second mixture, and uniformly dispersing to obtain a third mixture; S4: mixing amino resin and the third mixture, and uniformly dispersing to obtain a fourth mixture; S5: mixing catalyst, wetting agent, leveling agent, defoaming agent, water-based thickening agent, flatting powder, and the fourth mixture, and uniformly dispersing to obtain a first filtrate, wherein the first filtrate is the multifunctional water-based primer; In step S3, the first mixture and the second mixture are mixed by slowly adding the first mixture into the second mixture; In step S4, the amino resin and the third mixture are mixed by slowly adding the amino resin into the third mixture; The first mixture and the amino resin are added dropwise; The dispersion is by stirring; The water-based acrylic resin is carboxyl water-based acrylic resin and / or phosphate group modified water-based acrylic resin; The water-based silicone resin is water-based organosiloxane modified emulsion; The amino resin is one or more of fully methyl etherified amino resin, mixed etherified amino resin, and partially etherified high imino resin; The catalyst is a blocked acid catalyst, and the deblocking temperature of the blocked acid catalyst is 80-130°C; The solvent is one or more of diethylene glycol butyl ether, ethylene glycol butyl ether, dipropylene glycol butyl ether, and propylene glycol butyl ether; The wetting agent is one or more of BYK 349, BYK 346, TEGO Wet 245, and TEGO Wet 270; The leveling agent is one or more of BYK 333, BYK 3760, TEGO Glide 406, and TEGO Glide 410; The defoaming agent is one or more of BYK 3481, BYK 024, TEGO Foamex 810, and TEGO Foamex 825; The flatting powder is one or more of DOWSIL E-220A, DOWSIL E-1011, Grace C803, Grace SYLOID 7000, and WACKER ACEMATT TS100. ​ The aqueous thickening agent is one or more of the following: DEGOTEGO ViscoPlus 3030, TEGO ViscoPlus 3060, HEMMELTE RHEOLATE 299, and RHEOLATE FX 1010.

2. The method for preparing a multifunctional waterborne primer according to claim 1, characterized in that, The preparation method of the phosphate group modified aqueous acrylic resin specifically comprises the following steps: S10: uniformly mix the acrylate, phosphate and alcohol ether solvent in a mass ratio of 1: (0.8-1): (8-10), and then obtain a process solution by heating to 100°C; S20: Add initiator to the process solution at a mass ratio of =1:(35~40) and stir to disperse evenly. S30: cool to 50-60°C, then add an alkaline adjusting agent, adjust the pH to 7.5-8.5, and then obtain the phosphate group modified aqueous acrylic resin by uniformly dispersing.

3. Use of a multifunctional waterborne primer, characterized in that, The multifunctional aqueous primer prepared by the preparation method of claim 1 or 2 is coated on a metal substrate to form a paint film, and the metal substrate is made of aluminum alloy, magnesium alloy, stainless steel, iron, zinc alloy, copper or nickel; The coating on the metal substrate to form a paint film specifically comprises the following steps: S100: mix the multifunctional aqueous primer and deionized water, and then obtain a dispersion liquid by uniformly dispersing; S200: filter the dispersion liquid through a 150-300 mesh filter cloth to obtain a second filtrate; S300: spray the second filtrate on the metal substrate; S400: pre-bake the sprayed metal substrate at 60-80°C for 5-15 min, and then adjust the temperature to 140-170°C and bake for 25-35 min.

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