High-salt-fog-resistant water-based acrylic industrial paint emulsion, preparation method and application thereof

Abstract

The application discloses a high-salt-fog-resistance water-based acrylic industrial paint emulsion, a preparation method and application thereof, and belongs to the technical field of water-based paint emulsion. The application discloses a high-salt-fog-resistance water-based acrylic industrial paint emulsion, a preparation method and application thereof, and belongs to the technical field of water-based paint emulsion. The application discloses a high-salt-fog-resistance water-based acrylic industrial paint emulsion, a preparation method and application thereof, and belongs to the technical field of water-based paint emulsion. The application discloses a high-salt-fog-resistance water-based acrylic industrial paint emulsion, a preparation method and application thereof, and belongs to the technical field of water-based paint emulsion. The application discloses a high-salt-fog-resistance water-based acrylic industrial paint emulsion, a preparation method and application thereof, and belongs to the technical field of water-based paint emulsion. The application discloses a high-salt-fog-resistance water-based acrylic industrial paint emulsion, a preparation method and application thereof, and belongs to the technical field of water-based paint emulsion. The application discloses a high-salt-fog-resistance water-based acrylic industrial paint emulsion, a preparation method and application thereof, and belongs to the technical field

Description

Technical Field

[0001] This invention belongs to the field of waterborne industrial coatings technology, specifically relating to a high salt spray resistant waterborne acrylic industrial paint emulsion, its preparation method, and its application. Background Technology

[0002] Metal corrosion is an extremely serious problem in industrial production. It is estimated that the economic losses caused by metal corrosion each year can reach as high as 4% of the GDP. Coating metal surfaces with polymer protective films is one of the important means to effectively prevent metal corrosion, and water-based acrylic emulsions, as environmentally friendly coating base materials, play a key role in this process.

[0003] However, traditional water-based acrylic emulsions often struggle to simultaneously meet multiple requirements, including high salt spray resistance, high hardness, high gloss, and high water resistance, when applied to light / medium corrosion protection, colored roof tiles, and steel structures. This is especially true in coastal or saline-alkali areas, where the high salinity poses even more stringent challenges to the coating's corrosion resistance. Currently available acrylic emulsion products do not fully meet customer standards in terms of outdoor weather resistance, high salt spray resistance, high hardness, high gloss, and high water resistance. Furthermore, the production process of acrylic emulsions presents two main technical challenges: firstly, the size, shape, structure, and distribution of latex particles are difficult to control precisely, affecting the product's saturation, dispersibility, and stability; secondly, poor performance consistency between different batches leads to unstable coating performance, increasing maintenance costs. Summary of the Invention

[0004] To overcome the problems existing in the prior art, this invention provides a high salt spray resistance water-based acrylic industrial paint emulsion, its preparation method, and its application. The high salt spray resistance water-based acrylic industrial paint emulsion prepared by the method of this invention can solve the problem that existing acrylic emulsions are difficult to balance in terms of salt spray resistance, hardness, gloss, and water resistance, while improving the consistency between product batches.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] In one aspect, this invention provides a method for preparing a highly salt spray resistant water-based acrylic industrial paint emulsion, comprising the following steps:

[0007] (1) Dispersion preparation: Mix part of deionized water, composite emulsifier I and part of buffer evenly, add part of hard monomer, part of soft monomer, part of acidic monomer and part of functional monomer, disperse for 30-45 min to obtain dispersion;

[0008] (2) Preparation of core particle emulsion: Heat part of deionized water, composite emulsifier II and the remaining buffer to 80-95°C, add part of the dispersion and initiator I, react for 20-60 min to obtain core particle emulsion;

[0009] (3) Preparation of the core-shell emulsion in section I: A portion of the silane coupling agent is added to the remaining dispersion, and simultaneously added dropwise to the core particle emulsion with initiator II at 80-95°C, and then kept warm for 20-50 min to obtain the core-shell emulsion in section I;

[0010] (4) Preparation of the second-stage core-shell emulsion: The remaining hard monomer, remaining soft monomer, remaining acidic monomer, remaining functional monomer, remaining silane coupling agent and remaining composite emulsifier are mixed to form the second-stage shell mixture, which is simultaneously added dropwise to the first-stage core-shell emulsion at 80-95°C, and then kept warm for 60-90 min to obtain the second-stage core-shell emulsion;

[0011] (5) Stabilization treatment: Cool down to below 50°C, add pH adjuster to adjust pH to 7-8, add other additives, and filter to obtain the high salt spray resistant water-based acrylic industrial paint emulsion.

[0012] As a further embodiment of the present invention, the weight parts of each component are as follows: 550-850 parts of deionized water, 1-30 parts of composite emulsifier, 10-30 parts of acidic monomer, 400-600 parts of hard monomer, 100-300 parts of soft monomer, 10-40 parts of functional monomer, 2-20 parts of silane coupling agent, 4-8 parts of initiator, 1-10 parts of buffer, 7-15 parts of pH adjuster, and 1-10 parts of other additives.

[0013] As a further embodiment of the present invention: the composite emulsifier is a composite system composed of a reactive emulsifier and an anionic emulsifier;

[0014] And / or, the acidic monomer is selected from at least one of acrylic acid and methacrylic acid;

[0015] And / or, the hard monomer is selected from at least one of styrene and methyl methacrylate;

[0016] And / or, the soft monomer is selected from at least one of butyl acrylate and ethyl acrylate;

[0017] And / or, the functional monomer is at least one of ethyl methacrylate, phosphate methacrylate, and hexafluorobutyl acrylate;

[0018] And / or, the silane coupling agent is at least one of γ-(methacryloyloxy)propyltrimethoxysilane and vinyltriethoxysilane;

[0019] And / or, the initiator is selected from at least one of potassium persulfate and ammonium persulfate;

[0020] And / or, the buffer is selected from at least one of disodium hydrogen phosphate and sodium bicarbonate;

[0021] And / or, the pH adjuster is selected from at least one of ammonia and potassium hydroxide;

[0022] And / or, the other additives include defoamers and preservatives.

[0023] As a further embodiment of the present invention: the reactive emulsifier is selected from at least one of sodium allyloxyhydroxypropyl sulfonate and sodium 2-acrylamido-2-methylpropane sulfonate;

[0024] And / or, the anionic emulsifier is selected from at least one of sodium dodecyl sulfate and sodium dodecylbenzene sulfonate.

[0025] As a further aspect of the present invention: in step (1), the amount of the deionized water used is 28-32% of the total amount of deionized water;

[0026] And / or, in step (1), the amount of the composite emulsifier I is 28-32% of the total amount of the composite emulsifier;

[0027] And / or, in step (1), the amount of the partial buffer is 40-45% of the total amount of buffer;

[0028] And / or, in step (1), the amount of the partial hard monomer used is 40 to 45% of the total amount of hard monomer;

[0029] And / or, in step (1), the amount of the soft monomer used is 40 to 45% of the total amount of soft monomer;

[0030] And / or, in step (1), the amount of the acidic monomer used is 40 to 45% of the total amount of acidic monomer;

[0031] And / or, in step (1), the amount of the partial functional monomer used is 40 to 60% of the total amount of functional monomers;

[0032] And / or, in step (2), the amount of the deionized water used is 28-35% of the total amount of deionized water;

[0033] And / or, in step (2), the amount of composite emulsifier II is 28-32% of the total amount of composite emulsifier;

[0034] And / or, in step (2), the amount of the dispersion used in the portion is 5 to 15% of the total amount of dispersion;

[0035] And / or, in step (2), the amount of initiator I is 28-32% of the total amount of initiator;

[0036] And / or, in step (3), the amount of the partial silane coupling agent is 40-45% of the total amount of silane coupling agent;

[0037] And / or, in step (3), the amount of initiator II is 28-32% of the total amount of initiator;

[0038] And / or, the dropping process in steps (3) and (4) adopts a semi-continuous dropping process, with dropping times of 60-120 min and 120-200 min, respectively;

[0039] And / or, in step (4), the remaining initiator is added in the form of an aqueous solution, in an amount of 1 to 3% of the total amount of deionized water.

[0040] As a further aspect of the present invention: the preparation of the dispersion in step (1) specifically includes:

[0041] (1-1) Mix a portion of deionized water, composite emulsifier I and a portion of buffer evenly to obtain emulsifier solution I;

[0042] (1-2) Mix some hard monomers, some soft monomers, some acidic monomers and some functional monomers and slowly add them to the emulsifier solution I, disperse for 30-45 min to obtain the dispersion.

[0043] As a further aspect of the present invention: the preparation of the core-shell emulsion in step (3) specifically includes:

[0044] (3-1) Mix a portion of deionized water with initiator II to obtain catalyst solution I, wherein the amount of the portion of deionized water is 1 to 3% of the total amount of deionized water;

[0045] (3-2) Add a portion of the silane coupling agent to the remaining dispersion and disperse it evenly to obtain a shell-layer mixture of section I.

[0046] (3-3) At 80-95℃, the first shell-shell mixture and the catalyst solution I are added dropwise to the core particle emulsion, and then kept warm for 20-50 min to obtain the first core-shell emulsion.

[0047] As a further aspect of the present invention: the preparation of the second-stage core-shell emulsion in step (4) specifically includes:

[0048] (4-1) Mix a portion of deionized water with the remaining composite emulsifier to obtain an emulsifier solution, wherein the amount of the portion of deionized water is 30-42% of the total amount of deionized water;

[0049] (4-2) After mixing the remaining hard monomer, remaining soft monomer, remaining acidic monomer, remaining functional monomer and remaining silane coupling agent, add them to the emulsifier solution and disperse them to obtain the II shell layer mixture.

[0050] (4-3) The shell mixture of the second stage and the remaining initiator are simultaneously added dropwise to the core-shell emulsion of the first stage at 80-95°C, and then kept warm for 60-90 minutes to obtain the core-shell emulsion of the second stage.

[0051] In a second aspect, the present invention provides a highly salt-spray resistant water-based acrylic industrial paint emulsion, which is prepared by the above-described method for preparing highly salt-spray resistant water-based acrylic industrial paint emulsion.

[0052] In a third aspect, the present invention provides the application of the above-mentioned high salt spray resistant waterborne acrylic industrial paint emulsion in the preparation of waterborne industrial paint for metal protection.

[0053] The beneficial effects of this invention are as follows:

[0054] (1) This invention significantly improves the corrosion resistance of the coating by using a core-shell structure design and introducing functional monomers, making its salt spray resistance time reach more than 900 hours, which greatly exceeds the 500-hour level of conventional acrylic emulsions.

[0055] (2) This invention, through the design of multi-layered core-shell structured latex particles, endows the coating film with excellent gloss performance, with a gloss level of over 96%, which can fully meet the needs of highly decorative applications. At the same time, the coating film has high hardness and strong adhesion (grade 0), while maintaining good toughness, and has excellent comprehensive physical properties.

[0056] (3) This invention uses matched special functional monomers and employs a core-shell polymerization process to impart excellent water resistance to the coating film. The coating film does not turn white when immersed in water, and its water resistance is significantly better than that of conventional products. In addition, this system is a water-based system with low VOC content and no heavy metals, meeting the requirements for green environmental protection.

[0057] (4) This invention effectively solves the problem of large performance differences between different batches of products through standardized preparation process and multi-layer core-shell structure design, thus ensuring product consistency and stability. Attached Figure Description

[0058] Figure 1 This is a schematic diagram of the core-shell structure of the emulsion particles prepared in Example 1 of the present invention;

[0059] Figure 2 This is a graph showing the salt spray resistance of the emulsion prepared in Example 1 of this invention;

[0060] Figure 3 This is a graph showing the salt spray resistance of the acrylic emulsion in Comparative Example 1. Detailed Implementation

[0061] To enable those skilled in the art to better understand the technical solutions of the present invention, preferred embodiments of the present invention are described below in conjunction with specific examples, but these should not be construed as limiting the present patent. Unless otherwise specified, the experimental methods or testing methods described in the following embodiments are conventional methods; the reagents and materials, unless otherwise specified, are obtained from conventional commercial sources or prepared using conventional methods.

[0062] Example 1

[0063] A highly salt spray resistant water-based acrylic industrial paint emulsion, the raw materials of which are shown in Table 1:

[0064] Table 1

[0065]

[0066]

[0067] A method for preparing a highly salt spray resistant water-based acrylic industrial paint emulsion includes the following steps:

[0068] (1) Mix deionized water I, emulsifier I, and buffer I evenly to obtain emulsifier solution I. Mix hard monomer I, soft monomer I, acid monomer I, and functional monomer I and slowly add them to emulsifier solution I, disperse for 40 min to obtain a dispersion. Divide the dispersion into dispersion I and dispersion II at a weight ratio of 10% and 90%.

[0069] (2) Add deionized water II, emulsifier II and buffer II to the reactor and heat to 85°C. Mix dispersion I with initiator I (ammonium persulfate solution) and add to the reactor. React for 40 min to obtain core particle emulsion.

[0070] (3) Deionized water III and initiator II were mixed to obtain catalyst I. Silane coupling agent I was added to dispersion II and dispersed evenly to obtain a shell-shell mixture. At 85°C, the shell-shell mixture and catalyst I were simultaneously added dropwise to the core particle emulsion for 90 min, and the mixture was kept at this temperature for 30 min to obtain a core-shell emulsion.

[0071] (4) Deionized water IV was mixed with emulsifier III to obtain emulsifier solution II. Hard monomer II, soft monomer II, acid monomer II, functional monomer II and silane coupling agent II were mixed and slowly added to emulsifier solution II, and dispersed for 40 min to obtain the shell-shell mixture of section II. Deionized water V was mixed with initiator III to obtain catalyst solution II. At 85℃, the shell-shell mixture of section II and catalyst solution II were simultaneously added dropwise to the core-shell emulsion of section I for 150 min, and the mixture was kept at this temperature for 75 min to obtain the core-shell emulsion of section II.

[0072] (5) Cool the core-shell emulsion of stage II to 40°C, add pH adjuster to adjust pH to 7.5, add defoamer and preservative, and filter to obtain the final emulsion product.

[0073] Example 2

[0074] A highly salt spray resistant water-based acrylic industrial paint emulsion, the raw materials of which are shown in Table 2:

[0075] Table 2

[0076]

[0077]

[0078] A method for preparing a highly salt spray resistant water-based acrylic industrial paint emulsion includes the following steps:

[0079] (1) Mix deionized water I, emulsifier I, and buffer I evenly to obtain emulsifier solution I. Mix hard monomer I, soft monomer I, acid monomer I, and functional monomer I and slowly add them to emulsifier solution I, disperse for 40 min to obtain a dispersion. Divide the dispersion into dispersion I and dispersion II at a weight ratio of 10% and 90%.

[0080] (2) Add deionized water II, emulsifier II and buffer II to the reactor and heat to 85°C. Mix dispersion I with initiator I (ammonium persulfate solution) and add to the reactor. React for 40 min to obtain core particle emulsion.

[0081] (3) Deionized water III and initiator II were mixed to obtain catalyst I. Silane coupling agent I was added to dispersion II and dispersed evenly to obtain a shell-shell mixture. At 85°C, the shell-shell mixture and catalyst I were simultaneously added dropwise to the core particle emulsion for 90 min, and the mixture was kept at this temperature for 30 min to obtain a core-shell emulsion.

[0082] (4) Deionized water IV was mixed with emulsifier III to obtain emulsifier solution II. Hard monomer II, soft monomer II, acid monomer II, functional monomer II and silane coupling agent II were mixed and slowly added to emulsifier solution II, and dispersed for 40 min to obtain the shell-shell mixture of section II. Deionized water V was mixed with initiator III to obtain catalyst solution II. At 85℃, the shell-shell mixture of section II and catalyst solution II were simultaneously added dropwise to the core-shell emulsion of section I for 150 min, and the mixture was kept at this temperature for 75 min to obtain the core-shell emulsion of section II.

[0083] (5) Cool the core-shell emulsion of stage II to 40°C, add pH adjuster to adjust pH to 7.5, add defoamer and preservative, and filter to obtain the final emulsion product.

[0084] Example 3

[0085] A highly salt spray resistant water-based acrylic industrial paint emulsion, the raw materials of which are shown in Table 3:

[0086] Table 3

[0087]

[0088]

[0089] A method for preparing a highly salt spray resistant water-based acrylic industrial paint emulsion includes the following steps:

[0090] (1) Mix deionized water I, emulsifier I, and buffer I evenly to obtain emulsifier solution I. Mix hard monomer I, soft monomer I, acid monomer I, and functional monomer I and slowly add them to emulsifier solution I, disperse for 40 min to obtain a dispersion. Divide the dispersion into dispersion I and dispersion II at a weight ratio of 10% and 90%.

[0091] (2) Add deionized water II, emulsifier II and buffer II to the reactor and heat to 85°C. Mix dispersion I with initiator I (ammonium persulfate solution) and add to the reactor. React for 40 min to obtain core particle emulsion.

[0092] (3) Deionized water III and initiator II were mixed to obtain catalyst I. Silane coupling agent I was added to dispersion II and dispersed evenly to obtain a shell-shell mixture. At 85°C, the shell-shell mixture and catalyst I were simultaneously added dropwise to the core particle emulsion for 90 min, and the mixture was kept at this temperature for 30 min to obtain a core-shell emulsion.

[0093] (4) Deionized water IV was mixed with emulsifier III to obtain emulsifier solution II. Hard monomer II, soft monomer II, acid monomer II, functional monomer II and silane coupling agent II were mixed and slowly added to emulsifier solution II, and dispersed for 40 min to obtain the shell-shell mixture of section II. Deionized water V was mixed with initiator III to obtain catalyst solution II. At 85℃, the shell-shell mixture of section II and catalyst solution II were simultaneously added dropwise to the core-shell emulsion of section I for 150 min, and the mixture was kept at this temperature for 75 min to obtain the core-shell emulsion of section II.

[0094] (5) Cool the core-shell emulsion of stage II to 40°C, add pH adjuster to adjust pH to 7.5, add defoamer and preservative, and filter to obtain the final emulsion product.

[0095] Example 4

[0096] Unlike Example 1, the functional monomers used are phosphate methacrylate (10 parts, of which 6 parts are segment I and 4 parts are segment II); and hexafluorobutyl acrylate (15 parts, of which 8 parts are segment I and 7 parts are segment II), and the silane coupling agent used is vinyltriethoxysilane. The rest is the same as in Example 1.

[0097] Example 5

[0098] Unlike Example 1, the functional monomers used were phosphate methacrylate (10 parts, of which 4 parts were segment I and 6 parts were segment II); and hexafluorobutyl acrylate (15 parts, of which 10 parts were segment I and 5 parts were segment II), the silane coupling agent was vinyltriethoxysilane, and the initiator was potassium persulfate. The rest was the same as in Example 1.

[0099] The present invention also provides the following comparative examples.

[0100] Comparative Example 1

[0101] The only difference from Example 1 is that it does not contain functional monomers and silane coupling agents.

[0102] Comparative Example 2

[0103] The difference from Example 1 is that the hard monomer, soft monomer, acidic monomer and functional monomer are added all at once in step (1).

[0104] Comparative Example 3

[0105] The only difference from Example 1 is that no acidic monomer was added.

[0106] Comparative Example 4

[0107] The only difference from Example 1 is that no functional monomer was added.

[0108] Comparative Example 5

[0109] The only difference from Example 1 is that the functional monomer is replaced with glycidyl methacrylate.

[0110] Comparative Example 6

[0111] The only difference from Example 1 is that the functional monomer is replaced with hydroxyethyl methacrylate.

[0112] Comparative Example 7

[0113] The difference from Example 1 is only that the materials in Stage I and Stage II are mixed together, without segmented dripping, and are used only once. Specifically, the raw materials are shown in Table 4:

[0114] Table 4

[0115]

[0116]

[0117] Includes the following steps:

[0118] (1) Combine the two parts of the emulsion at the core and shell ends in Example 1, prepare without segmentation, disperse for 40 min to obtain a dispersion, heat to 85°C, add initiator I, and then drop the dispersion into the core particle emulsion for 240 min, and keep warm for 75 min.

[0119] (2) After the above materials have been kept warm, cool them down to 40°C, add a pH adjuster to adjust the pH to 7.5, add an antifoaming agent and a preservative, and filter to obtain the final emulsion product.

[0120] Comparative Example 8

[0121] Commercially available product: Acrylic emulsion with model number XG-928 produced by Hengshui Xinguang New Material Technology Co., Ltd.

[0122] Effect Example

[0123] The emulsions of Examples 1-5 and Comparative Examples 1-8 were tested using the following methods:

[0124] 1. Salt spray resistance time: Conducted according to the method specified in ASTM B117-19.

[0125] 2. Gloss: Performed according to the method specified in GB / T 9754-2025.

[0126] 3. Adhesion: Tested according to the method specified in GB / T 9286-2021.

[0127] IV. Pencil hardness: Tested according to the method specified in GB / T 6739-2022.

[0128] V. Water resistance: Tested according to the method specified in GB / T 1733-1993.

[0129] VI. Storage stability: Tested according to the methods specified in GB / T 6753.3-1986.

[0130] The emulsions of Examples 1-5 and Comparative Examples 1-8 were tested, and the test results are shown in Table 5.

[0131] Table 5

[0132]

[0133]

[0134] As shown in Table 5, the acrylic emulsions prepared in Examples 1-5 of this invention are significantly superior to commercially available acrylic emulsions and comparative examples 1-7 in terms of key performance indicators such as salt spray resistance, gloss, and hardness. Among them, Examples 2 and 4 show the best technical effects.

[0135] also, Figure 1 This is a schematic diagram of the core-shell structure of the emulsion particles prepared in Example 1 of the present invention. Specifically, the yellow part inside is the core layer and the blue part outside is the shell layer. Figure 2 and Figure 3 The figures show the salt spray resistance of the emulsions prepared in Example 1 and Comparative Example 1 of this invention, respectively. As can be seen from the figures, Example 1 can effectively protect the substrate, while the comparative example shows rust exceeding 2 mm and severe blistering.

[0136] This invention successfully developed a water-based acrylic industrial paint emulsion with high salt spray resistance, high hardness, high gloss, and high water resistance through multi-layered core-shell structure design, introduction of functional monomers, and precise control of the preparation process. This product not only boasts excellent performance but also good environmental friendliness and strong batch-to-batch consistency, meeting the metal protection requirements in harsh environments and possessing broad application prospects.

[0137] Finally, it should be noted that in this invention, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus.

[0138] Although this disclosure has been described above through specific embodiments, it should be understood that those skilled in the art can devise various modifications, improvements, or equivalents to this disclosure within the spirit and scope of the appended solutions. Such modifications, improvements, or equivalents should also be considered to be included within the scope of protection claimed in this disclosure.

Claims

1. A method for preparing a water-based acrylic industrial paint emulsion with high salt spray resistance, characterized in that, Includes the following steps: (1) Preparation of dispersion: Mix part of deionized water, composite emulsifier I and part of buffer evenly, add part of hard monomer, part of soft monomer, part of acidic monomer and part of functional monomer, disperse for 30~45min to obtain dispersion; The amount of the composite emulsifier I is 28-32% of the total amount of the composite emulsifier; the amount of the partial hard monomer is 40-45% of the total amount of the hard monomer; the amount of the partial soft monomer is 40-45% of the total amount of the soft monomer; the amount of the partial acidic monomer is 40-45% of the total amount of the acidic monomer; and the amount of the partial functional monomer is 40-60% of the total amount of the functional monomer. (2) Preparation of core particle emulsion: Part of deionized water, composite emulsifier II and the remaining buffer are heated to 80~95℃, part of the dispersion and initiator I are added, and the reaction is carried out for 20~60min to obtain core particle emulsion; the amount of composite emulsifier II is 28~32% of the total amount of composite emulsifier; the amount of the part of the dispersion is 5~15% of the total amount of dispersion. (3) Preparation of the first-stage core-shell emulsion: A portion of the silane coupling agent is added to the remaining dispersion, and simultaneously added dropwise to the core particle emulsion along with initiator II at 80-95°C, and then kept at this temperature for 20-50 minutes to obtain the first-stage core-shell emulsion; the amount of the portion of the silane coupling agent is 40-45% of the total amount of silane coupling agent; (4) Preparation of the second-stage core-shell emulsion: The remaining hard monomer, remaining soft monomer, remaining acidic monomer, remaining functional monomer, remaining silane coupling agent and remaining composite emulsifier are mixed to form the second-stage shell mixture, which is simultaneously added dropwise to the first-stage core-shell emulsion at 80~95℃ and then kept warm for 60~90min to obtain the second-stage core-shell emulsion; (5) Stabilization treatment: Cool down to below 50°C, add pH adjuster to adjust pH to 7~8, add other additives, and filter to obtain the high salt spray resistant water-based acrylic industrial paint emulsion; The composite emulsifier is a composite system composed of a reactive emulsifier and anionic emulsifier; the acidic monomer is methacrylic acid; the hard monomer is methyl methacrylate; the soft monomer is butyl acrylate; the functional monomer is hexafluorobutyl acrylate, or a combination of hexafluorobutyl acrylate and phosphate methacrylate; and the silane coupling agent is at least one of γ-(methacryloyloxy)propyltrimethoxysilane and vinyltriethoxysilane. The weight parts of each component are as follows: 550-850 parts of deionized water, 1-30 parts of composite emulsifier, 10-30 parts of acidic monomer, 400-600 parts of hard monomer, 100-300 parts of soft monomer, 10-40 parts of functional monomer, 2-20 parts of silane coupling agent, 4-8 parts of initiator, 1-10 parts of buffer, 7-15 parts of pH adjuster, and 1-10 parts of other additives.

2. The method for preparing the high salt spray resistant waterborne acrylic industrial paint emulsion according to claim 1, characterized in that, The initiator is selected from at least one of potassium persulfate and ammonium persulfate; And / or, the buffer is selected from at least one of disodium hydrogen phosphate and sodium bicarbonate; And / or, the pH adjuster is selected from at least one of ammonia and potassium hydroxide; And / or, the other additives include defoamers and preservatives.

3. The method for preparing the high salt spray resistant waterborne acrylic industrial paint emulsion according to claim 2, characterized in that, The reactive emulsifier is selected from at least one of sodium allyloxyhydroxypropyl sulfonate and sodium 2-acrylamido-2-methylpropane sulfonate. And / or, the anionic emulsifier is selected from at least one of sodium dodecyl sulfate and sodium dodecylbenzene sulfonate.

4. The method for preparing the high salt spray resistant waterborne acrylic industrial paint emulsion according to claim 1, characterized in that, In step (1), the amount of deionized water used is 28-32% of the total amount of deionized water; And / or, in step (1), the amount of the buffer is 40-45% of the total amount of buffer; And / or, in step (2), the amount of the deionized water used is 28-35% of the total amount of deionized water; And / or, in step (2), the amount of initiator I is 28-32% of the total amount of initiator; And / or, in step (3), the amount of initiator II is 28-32% of the total amount of initiator; And / or, the dripping process in steps (3) and (4) adopts a semi-continuous dripping process, with dripping times of 60~120min and 120~200min respectively; And / or, in step (4), the remaining initiator is added in the form of an aqueous solution, the amount of which is 1 to 3% of the total amount of deionized water.

5. The method for preparing the high salt spray resistant waterborne acrylic industrial paint emulsion according to claim 1, characterized in that, The preparation of the dispersion in step (1) specifically includes: (1-1) Mix a portion of deionized water, composite emulsifier I, and a portion of buffer to obtain emulsifier solution I; (1-2) Mix some hard monomers, some soft monomers, some acidic monomers and some functional monomers and slowly add them to the emulsifier solution I, disperse for 30-45 min to obtain the dispersion.

6. The method for preparing the high salt spray resistant waterborne acrylic industrial paint emulsion according to claim 1, characterized in that, The preparation of the core-shell emulsion in step (3) specifically includes: (3-1) Mix a portion of deionized water with initiator II to obtain catalyst solution I, wherein the amount of the deionized water is 1-3% of the total amount of deionized water; (3-2) Add a portion of the silane coupling agent to the remaining dispersion and disperse it evenly to obtain a shell-layer mixture of section I; (3-3) At 80~95℃, the first shell-shell mixture and the catalyst solution I are added dropwise to the core particle emulsion, and then kept warm for 20~50 min to obtain the first core-shell emulsion.

7. The method for preparing the high salt spray resistant waterborne acrylic industrial paint emulsion according to claim 1, characterized in that, The preparation of the second-stage core-shell emulsion in step (4) specifically includes: (4-1) Mix a portion of deionized water with the remaining composite emulsifier to obtain an emulsifier solution, wherein the amount of the deionized water is 30-42% of the total amount of deionized water; (4-2) Mix the remaining hard monomer, remaining soft monomer, remaining acidic monomer, remaining functional monomer and remaining silane coupling agent, add them to the emulsifier solution and disperse them to obtain the second-stage shell mixture. (4-3) The shell mixture of the second stage and the remaining initiator are simultaneously added dropwise to the core-shell emulsion of the first stage at 80~95℃, and then kept warm for 60~90min to obtain the core-shell emulsion of the second stage.

8. A high salt spray resistant waterborne acrylic industrial paint emulsion, which is prepared by the preparation method of the high salt spray resistant waterborne acrylic industrial paint emulsion according to any one of claims 1 to 7.

9. The application of the high salt spray resistant waterborne acrylic industrial paint emulsion as described in claim 8 in the preparation of waterborne industrial paint for metal protection.

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