A high-performance water-based single-component zinc plating-like paint, its preparation method and application

Abstract

This invention discloses a high-performance water-based single-component imitation zinc plating paint, its preparation method, and its application. The raw materials of the paint include LH-38X resin and zinc powder. The raw materials of LH-38X resin include, by weight, 6-8 parts of methyl methacrylate, 5-7 parts of butyl acrylate, 1-3 parts of methoxy polyethylene glycol methacrylate, 1-3 parts of acrylic acid, 0.7-0.9 parts of benzoyl peroxide, 0.3-0.5 parts of n-dodecyl mercaptan, 1-3 parts of organosilicon intermediate, 16-18 parts of epoxy resin, 2-4 parts of fatty acid, 0.2-0.4 parts of tetrabutylammonium bromide, 0.03-0.1 parts of zinc oxide, 3-5 parts of dimethyl ethanolamine, 0.8-1 parts of flash etchant, 2-4 parts of anti-settling agent, and 52-58 parts of propylene glycol methyl ether. The paint of this invention has an adhesion of 5MPa, a salt spray resistance of 2000h, a total zinc content of >93%, and a metallic zinc content of >90%, which meets the environmental protection requirements of GB30981-2020.

Description

Technical Field

[0001] This invention relates to the field of paint technology, specifically to a high-performance water-based single-component imitation zinc plating paint, its preparation method, and its application. Background Technology

[0002] The cathodic protection effect of zinc powder in galvanized steel imitation coatings gives the coating excellent corrosion resistance, making it widely used in metal protection. With the development of water-based coatings, most commercially available water-based galvanized steel imitation coatings are two-component products. Due to their viscous consistency, they are difficult to mix evenly during application, affecting coating performance and reducing application efficiency. In contrast, water-based one-component galvanized steel imitation paints are easy to apply, thus the development of high-performance water-based one-component galvanized steel imitation paints has broad market prospects. Summary of the Invention

[0003] The technical problem to be solved by this invention is how to obtain a high-performance single-component imitation zinc plating paint.

[0004] The present invention solves the above-mentioned technical problems through the following technical means:

[0005] A high-performance water-based single-component imitation zinc plating paint, the raw materials of which include LH-38X resin and zinc powder; the raw materials of LH-38X resin include, by weight: 6-8 parts methyl methacrylate, 5-7 parts butyl acrylate, 1-3 parts methoxy polyethylene glycol methacrylate, 1-3 parts acrylic acid, 0.7-0.9 parts benzoyl peroxide, 0.3-0.5 parts n-dodecyl mercaptan, 1-3 parts organosilicon intermediate, 16-18 parts epoxy resin, 2-4 parts fatty acid, 0.2-0.4 parts tetrabutylammonium bromide, 0.03-0.1 parts zinc oxide, 3-5 parts dimethyl ethanolamine, 0.8-1 parts flash etchant, 2-4 parts anti-settling agent, and 52-58 parts propylene glycol methyl ether.

[0006] Preferably, the mass ratio of LH-38X resin to zinc powder is 14-16:84-86.

[0007] Preferably, the preparation method of the LH-38X resin includes the following steps:

[0008] S1. Methyl methacrylate, butyl acrylate, methoxy polyethylene glycol methacrylate, acrylic acid, n-dodecyl mercaptan and benzoyl peroxide initiator are mixed to prepare a monomer mixture; a portion of propylene glycol methyl ether is stirred and heated, and then added dropwise to the monomer mixture, and the reaction is maintained at the temperature to obtain an acrylate polymer.

[0009] S2. Epoxy resin, fatty acid, tetrabutylammonium bromide, and another portion of propylene glycol methyl ether are added to the reaction apparatus, and the mixture is heated and kept at the temperature to prepare the epoxy graft. During the heat preservation reaction, a portion of propylene glycol methyl ether is added to balance the temperature.

[0010] S3. Add epoxy graft, acrylate polymer, organosilicon intermediate and zinc oxide to the reaction apparatus, heat and react. After the reaction is completed, cool to room temperature, add another part of propylene glycol methyl ether, and then add dimethyl ethanolamine to obtain a mixture.

[0011] S4. After mixing the above mixture with the flash etchant and the anti-settling agent and dispersing it evenly, add the remaining propylene glycol methyl ether to obtain the LH-38X resin.

[0012] Preferably, in S1, the monomer mixture is added dropwise after stirring and heating to 95°C; the monomer mixture is added dropwise over 2-3 hours, with the temperature controlled at 100-105°C throughout the addition process; after addition, the reaction is maintained at 100-110°C for 3 hours; in S2, the reaction temperature is maintained at 110-120°C until the acid value is ≤1mgKOH / g; in S3, the temperature is raised to 110-120°C until the acid value is ≤28mgKOH / g.

[0013] Preferably, the epoxy resin is epoxy resin E12; and the fatty acid is linoleic acid.

[0014] Preferably, the organosilicon intermediate is a dimethylsiloxane and diphenylsiloxane condensate.

[0015] Preferably, the flash etchant is one or a mixture of ZT703, ZT705, and ZT707 from Beijing Zhitu Chemical Co., Ltd.; the anti-settling agent is one or a mixture of two of BYK420 and BYK428 from BYK Chemical Co., Ltd.; and the zinc powder is 800-1000 mesh zinc powder.

[0016] Preferably, in step S4, the dispersion is uniform in a disperser at a speed of 1500 r / min for 30 min.

[0017] The present invention also proposes a method for preparing the high-performance water-based single-component imitation zinc plating paint, comprising the following steps: mixing LH-38X resin and zinc powder uniformly to obtain the high-performance water-based single-component imitation zinc plating paint.

[0018] Preferably, the preparation method of the high-performance water-based single-component imitation zinc-plating paint includes the following steps: adding LH-38X resin into a batching device, adding zinc powder under stirring at 300 r / min, then adjusting the speed to 600-800 r / min, maintaining stirring for 30 min, controlling the outlet material temperature to ≤50℃ for discharge, and obtaining the high-performance water-based single-component imitation zinc-plating paint.

[0019] The present invention also proposes an application of the aforementioned high-performance water-based single-component zinc plating-like paint on metal surfaces.

[0020] In this invention, during the preparation of LH-38X resin, one side of the epoxy resin is first ring-opened with fatty acids, and the other side is ring-opened with a carboxyl-containing acrylate polymer. The carboxyl groups in the carboxyl-containing acrylate polymer are introduced into the acrylate prepolymer by the acrylic acid, organically combining the three into a single resin. The epoxy resin in this resin structure provides excellent adhesion, water resistance, and salt spray resistance to the coating film. The long-chain aliphatic hydrocarbons act as internal plasticizers, giving the high pigment-to-binder ratio system sufficient flexibility. The double bonds it contains also facilitate oxidative polymerization. The acrylate polymer portion not only introduces carboxyl groups to ensure the system's water-based properties but also ensures fast drying during film formation, facilitating water evaporation. Therefore, the coating film possesses the flexibility of the long-chain aliphatic hydrocarbons, the fast-drying and anti-aging properties of acrylic acid, and the excellent adhesion and salt spray resistance of epoxy resin. This organic combination allows for the complementary use of performance advantages. This resin system is water-free and contains its own phase inversion catalyst, tetrabutylammonium bromide. Therefore, it can be diluted indefinitely with water without showing a significant dilution peak.

[0021] In this invention, organosilicon chemistry is applied to the epoxy polymerization of acrylic acid during the preparation of LH-38X resin, resulting in a product that combines the advantages of three materials. Because organosilicon functional groups (Si-O bonds) are introduced into the resin, the anchoring groups are anchored to the zinc powder. This provides a water barrier when the product is diluted with water during application. Simultaneously, the Si-O bonds increase the crosslinking density of the coating film during resin curing, accelerating the transformation of the resin from a linear polymer to a three-dimensional structure. Furthermore, the organosilicon intermediates in this invention are dimethylsiloxane and diphenylsiloxane condensation units with relatively small molecular weights. Their functional groups are adsorbed onto the zinc powder surface, providing stability to the zinc powder during dilution with water during application.

[0022] This invention relates to a high-performance water-based single-component imitation zinc-plating paint, requiring salt spray resistance ≥2000h, adhesion ≥5MPa, total zinc content ≥93%, and metallic zinc content ≥90%. By incorporating the flash etchant and anti-settling agent into the resin during the later stages of resin synthesis, not only is high dispersibility of both agents within the system ensured, but the finished paint also meets both total and metallic zinc content requirements. If a process is used where resin liquid, flash etchant, anti-settling agent, and zinc powder are added sequentially, the system temperature is high and the air concentration is high before the zinc powder is added, which only ensures the total zinc content meets the requirements; therefore, the metallic zinc content fluctuates, sometimes dropping to around 82-85%. Since the LH-38X resin system does not contain water, the paint formulation uses LH-38X resin with direct addition of zinc powder.

[0023] In the production process of the high-performance water-based single-component imitation zinc-plating paint of this invention, LH-38X resin is the key material for paint making. The resin synthesis adopts an automatic temperature control device and a numerical control dropper, thereby effectively controlling the reaction rate and polymerization time, which can make the molecular weight distribution of the synthesized resin narrow and the molecular weight moderate, ensuring that no obvious dilution peak appears, thus obtaining an ideal paint film. The selection of zinc powder is also very important. The zinc powder dispersion process in LH-38X resin is the final control of product quality to achieve satisfactory results.

[0024] Advantages of this invention:

[0025] (1) This invention uses a carboxyl-containing acrylic copolymer, a long-chain aliphatic hydrocarbon monocarboxylic acid, and an organosilicon intermediate to modify epoxy resin, organically combining the various substances into a whole resin, which has excellent film-forming properties in aqueous media, good adhesion, and good salt spray resistance. The introduction of organosilicon intermediate enhances the stability of zinc powder in aqueous systems, solves the problems of coating flexibility and wettability of zinc powder, solves the water-based problem, and has the characteristics of fast drying film formation, as well as the characteristics of good adhesion and salt spray resistance and the stability of zinc powder, thereby ensuring the stability of the zinc content.

[0026] (2) The high-performance water-based single-component imitation galvanized paint of the present invention is suitable for long-term corrosion protection of steel surfaces, replacing traditional hot-dip galvanizing and thermal spraying, achieving better protective effects than hot-dip galvanizing and thermal spraying. It can be used alone as a metal anti-corrosion protective layer and a primer for heavy-duty anti-corrosion coating systems, and can also be used to repair damage to various galvanized coatings on steel structures caused by corrosion, welding, cutting, and riveting. It is widely used for corrosion protection of various steel components and facilities, such as power transmission and transformation systems, power generation systems, bridge steel structures, concrete steel structures, steel structure buildings, marine facilities, high-speed railway and highway facilities, water conservancy facilities, civil defense facilities, petrochemical equipment, etc.

[0027] (3) The high-performance water-based single-component imitation zinc plating paint of this invention has an adhesion of 5MPa, a salt spray resistance of 2000h, a total zinc content of >93%, and a metallic zinc content of >90%, fully complying with the environmental protection requirements of GB30981-2020. It can be directly diluted with water during construction, meeting environmental protection requirements. The resin system does not contain water, but it can be infinitely diluted with water without showing a significant dilution peak. The VOC of the finished paint is 270-276g / L, which meets the requirement of VOC≤300g / L (GB30981-2020 Metal Substrate Protective Coating Single-component Primer). Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0029] Unless otherwise specified, all test materials and reagents used in the following examples are commercially available.

[0030] Unless otherwise specified in the embodiments, the techniques or conditions described in the literature in this field or in accordance with the product manual may be followed.

[0031] Example 1

[0032] Preparation of LH-38X resin used in high-performance waterborne single-component imitation zinc plating paint

[0033] Raw materials used in the synthesis of LH-38X resin

[0034] 1.1 Material Composition

[0035] Methyl methacrylate (MMA), butyl acrylate (BA), methoxy polyethylene glycol methacrylate (MPEG-MA), acrylic acid (AA), benzoyl peroxide (BPO), n-dodecyl mercaptan, epoxy resin (E12), fatty acids (linolenic acid with an iodine value of 160-180 mg KOH / g, Anhui Ruifende Oil Deep Processing Co., Ltd.), tetrabutylammonium bromide, zinc oxide, organosilicon intermediates dimethylsiloxane and diphenylsiloxane condensate (Dow Chemical), dimethylethanolamine, flash etchant (Beijing Zhitu Chemical Co., Ltd. ZT703), anti-settling agent (BYK420 from BYK Chemical), propylene glycol methyl ether, all are industrial grade, and zinc oxide is analytical grade.

[0036] 1.2 Parts by weight of raw material components of LH-38X resin

[0037]

[0038]

[0039] 1.3LH-38X Resin Production Process:

[0040] (1) Preparation of acrylate polymers

[0041] a. First, mix the prescribed amounts of methyl methacrylate, butyl acrylate, methoxy polyethylene glycol methacrylate, acrylic acid, n-dodecyl mercaptan and initiator benzoyl peroxide to form a monomer mixture, and place it in a dropping vessel.

[0042] b. Add 1 / 4 part by weight of propylene glycol methyl ether as a base in a reactor equipped with a reflux device, start stirring, heat to 95°C, and begin to add the monomer mixture dropwise. The addition is completed in 2 hours. The temperature is controlled at 100-105°C throughout the entire addition process. After the addition is completed, keep the temperature at 100-110°C for 3 hours to obtain the acrylate polymer.

[0043] (2) Preparation of epoxy grafts

[0044] Epoxy resin, fatty acid, tetrabutylammonium bromide, and 1 / 3 part by weight of propylene glycol methyl ether were added to a reactor equipped with a reflux device. The temperature was raised until the epoxy resin melted and stirring was started. The mixture was kept at 110-120℃ for 2 hours. As the azeotropic point increased, some propylene glycol methyl ether was added to balance the temperature. After 2 hours, a sample was taken to measure the acid value. The reaction endpoint was reached when the acid value was ≤1mgKOH / g, and the epoxy grafted product was obtained.

[0045] (3) Preparation of LH-38X resin

[0046] a. Add epoxy graft, acrylate polymer, organosilicon intermediate and zinc oxide to the reaction vessel, heat to 110-120℃ and maintain for 2 hours. After 2 hours, take a sample to measure the acid value. When the acid value is ≤28mgKOH / g, cool to room temperature, add some propylene glycol methyl ether to reduce viscosity, and then add dimethyl ethanolamine to neutralize the pH value of the system to the range of 7-9.

[0047] b. Transfer the obtained mixture into a high-speed disperser, add flash etchant and anti-settling agent in sequence, maintain at 1500 r / min for 30 min, add the remaining propylene glycol methyl ether, and obtain LH-38X resin.

[0048] 1.4LH-38X Resin Test Results

[0049]

[0050]

[0051] Example 2

[0052] Preparation of high-performance water-based single-component imitation zinc plating paint

[0053] Main raw materials

[0054] 2.1 Material Composition

[0055] The LH-38X resin and 800-mesh zinc powder prepared in Example 1 are industrial grade. The 800-mesh zinc powder used in this example (purchased from Hunan Xinweiling Metal New Material Technology Co., Ltd.) is an industrial grade.

[0056] 2.2 The weight (kg) of each component of the high-performance water-based single-component imitation galvanized paint is as follows:

[0057] LH-38X resin 14, zinc powder (800 mesh) 86.

[0058] 2.3 The preparation process of high-performance water-based single-component imitation zinc plating paint is as follows:

[0059] (1) Put LH-38X resin into the mixing tank, start the high-speed disperser, and add zinc powder while stirring at a slow speed of 300r / min.

[0060] (2) After the zinc powder is added, adjust the speed to 600-800 r / min and keep stirring for 30 min until the mixture is uniform (the scraper is flat and free of particles). Control the outlet material temperature to ≤50℃. Stop stirring, filter and package to obtain high-performance water-based single-component imitation zinc plating paint.

[0061] 2.4 Test results of high-performance water-based single-component imitation zinc plating paint (referencing HG / T4845-2015 Cold-applied zinc coatings (oil-based))

[0062]

[0063]

[0064] Comparative Example 1

[0065] The only difference from Example 1 is that:

[0066] 1.2 Parts by weight of raw material components of LH-38X resin

[0067]

[0068] In the production process of 1.3LH-38X resin, during the preparation of the acrylate polymer, dropwise b is completed in 2.5 hours.

[0069] Comparative Example 2

[0070] The only difference from Example 1 is that:

[0071] 1.2 Parts by weight of raw material components of LH-38X resin

[0072]

[0073] In the production process of 1.3LH-38X resin, during the preparation of the acrylate polymer, dropwise part b is completed in 3 hours.

[0074] In the comparative example, the mass ratios of epoxy grafting material, acrylate polymer, and silicone intermediate in the preparation of LH-38X resin differed from those in Example 1, which will affect the coating performance of the product.

[0075] Comparative Example 3

[0076] The coatings prepared using the resins prepared in Comparative Examples 1 and 2 instead of the resin in Example 2 were compared in the following table:

[0077] Zinc content in non-volatile substances / % ≥ 91.6 91.2 91.3 Total zinc content in non-volatile substances ≥ 93.4 93.2 93.2 Adhesion (pull-off method) / MPa ≥ 6.23 4.30 5.84 Salt spray test / 2000h conform to 1200h 850h surface dry min 20 15 20

[0078] The test results above show that a high epoxy content results in good adhesion and salt spray resistance; a high acrylic content leads to fast drying; and the silicone content has a stabilizing effect on zinc powder.

[0079] Comparative Example 4

[0080] The only difference from Example 1 is that: the raw material components of LH-38X resin do not contain methoxy polyethylene glycol methacrylate, and the acrylate polymer is prepared according to the mass ratio of methyl methacrylate: butyl acrylate: acrylic acid: benzoyl peroxide: n-dodecyl mercaptan of 7:5.5:2:0.8:0.4; the epoxy graft is prepared according to the mass ratio of epoxy resin: fatty acid: tetrabutylammonium bromide of 16.8:2.9:0.25; the total content of acrylate polymer is kept unchanged when preparing LH-38X resin, that is, in the preparation process of (3) LH-38X resin, the mass ratio of acrylate polymer, epoxy graft and organosilicon intermediate is the same as in Example 1.

[0081] Comparative Example 5

[0082] The only difference from Example 1 is that epoxy resin E18 is used instead of E12 in the raw material components of LH-38X resin, while keeping its amount unchanged.

[0083] Comparative Example 6

[0084] The resins prepared in Comparative Examples 4 and 5 were used instead of the resin in Example 2 to prepare coatings, and their performance was compared as shown in the table below:

[0085]

[0086] The test results above show that without the MPEG-MA system, the viscosity is high, the water solubility is poor, the drying properties are poor, and the initial water resistance is poor; replacing it with an epoxy resin with a high epoxy value results in poor water solubility, poor drying properties, and poor initial water resistance.

[0087] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A high-performance water-based single-component imitation zinc plating paint, characterized in that: The raw materials include LH-38X resin and zinc powder; the raw materials of LH-38X resin, by weight, include: 6-8 parts methyl methacrylate, 5-7 parts butyl acrylate, 1-3 parts methoxy polyethylene glycol methacrylate, 1-3 parts acrylic acid, 0.7-0.9 parts benzoyl peroxide, 0.3-0.5 parts n-dodecyl mercaptan, 1-3 parts organosilicon intermediate, 16-18 parts epoxy resin, 2-4 parts fatty acid, 0.2-0.4 parts tetrabutylammonium bromide, 0.03-0.1 parts zinc oxide, 3-5 parts dimethyl ethanolamine, 0.8-1 parts flash etchant, 2-4 parts anti-settling agent, and 52-58 parts propylene glycol methyl ether; the mass ratio of LH-38X resin to zinc powder is 14-16:84-86; the preparation method of LH-38X resin includes the following steps: S1. Methyl methacrylate, butyl acrylate, methoxy polyethylene glycol methacrylate, acrylic acid, n-dodecyl mercaptan and benzoyl peroxide initiator are mixed to prepare a monomer mixture; a portion of propylene glycol methyl ether is stirred and heated, and then added dropwise to the monomer mixture, and the reaction is maintained at the temperature to obtain an acrylate polymer. S2. Epoxy resin, fatty acid, tetrabutylammonium bromide, and another portion of propylene glycol methyl ether are added to the reaction apparatus, and the mixture is heated and kept at the temperature to prepare the epoxy graft. During the heat preservation reaction, a portion of propylene glycol methyl ether is added to balance the temperature. S3. Add epoxy graft, acrylate polymer, organosilicon intermediate and zinc oxide to the reaction apparatus, heat and react. After the reaction is completed, cool to room temperature, add another part of propylene glycol methyl ether, and then add dimethyl ethanolamine to obtain a mixture. S4. After mixing the above mixture with the flash etchant and the anti-settling agent and dispersing it evenly, add the remaining propylene glycol methyl ether to obtain the LH-38X resin.

2. The high-performance water-based single-component imitation zinc plating paint according to claim 1, characterized in that: In S1, the monomer mixture is added dropwise after stirring and heating to 95℃; the monomer mixture is added dropwise over 2-3 hours, with the temperature controlled at 100-105℃ throughout the entire addition process. After the addition is complete, the reaction is maintained at 100-110℃ for 3 hours. In S2, the reaction temperature is maintained at 110-120℃ until the acid value is ≤1mgKOH / g. In S3, the temperature is raised to 110-120℃ until the acid value is ≤28mgKOH / g.

3. The high-performance water-based single-component imitation zinc plating paint according to claim 1, characterized in that: The epoxy resin is epoxy resin E12; the fatty acid is linoleic acid.

4. The high-performance water-based single-component imitation zinc plating paint according to claim 1, characterized in that: The organosilicon intermediate is a condensation polymer of dimethylsiloxane and diphenylsiloxane.

5. The high-performance water-based single-component imitation zinc plating paint according to any one of claims 1-4, characterized in that: The flash etchant is one or a mixture of ZT703, ZT705, and ZT707; the anti-settling agent is one or a mixture of two of BYK420 and BYK428; and the zinc powder is 800-1000 mesh zinc powder.

6. A method for preparing a high-performance water-based single-component imitation zinc plating paint as described in any one of claims 1-5, characterized in that: The process includes the following steps: mixing LH-38X resin and zinc powder evenly to obtain the high-performance water-based single-component imitation zinc plating paint.

7. The method for preparing high-performance water-based single-component imitation zinc plating paint according to claim 6, characterized in that: The process includes the following steps: adding LH-38X resin into a batching device, adding zinc powder while stirring at 300 r / min, then adjusting the speed to 600-800 r / min, maintaining stirring for 30 min, and controlling the outlet material temperature to ≤50℃ to obtain the high-performance water-based single-component imitation zinc plating paint.

8. The application of a high-performance water-based single-component imitation zinc plating paint as described in any one of claims 1-5 on a metal surface.

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