Solvent-free and plasticizer-free spraying type metal anticorrosive paint and preparation method thereof

Abstract

The invention relates to the technical field of anticorrosive paint, in particular to solvent-free and plasticizer-free spraying type metal anticorrosive paint and a preparation method thereof.The solvent-free and plasticizer-free spraying type metal anticorrosive paint is prepared from, by weight, 40-60 parts of polysiloxane resin, 30-50 parts of reactive diluent, 0.3-1 part of epoxy silane coupling agent, 1-3 parts of amino silane coupling agent, 30-40 parts of silica powder and 0.15-0.4 part of organic tin. 1 to 3 parts of vinyl trimethoxy silane, 0.4 to 1.6 parts of anti-aging agent and 0.1 to 0.5 part of polyamide wax; 0.3 to 0.8 part of an organic silicon defoaming agent; by optimizing the matching of the modified polysiloxane resin, the reactive diluent and other raw materials and controlling the addition amount, the provided product achieves high solid content and low viscosity, and comprehensive properties such as adhesive force and mechanical properties are guaranteed while the spraying construction requirement is met.

Description

Technical Field

[0001] This invention relates to the field of anti-corrosion coating technology, specifically to a solvent-free, plasticizer-free sprayable metal anti-corrosion coating and its preparation method. Background Technology

[0002] Traditional solvent-based coatings can be flexibly adjusted in solvent ratio to meet different application methods, but the resulting coating performance needs further improvement and does not meet increasingly stringent environmental protection requirements. Spray application requires the coating to have a suitable viscosity for good atomization. Excessive viscosity leads to poor atomization and uneven paint film; excessively low viscosity easily causes sagging. Achieving the required low viscosity for spraying without solvent dilution is extremely difficult. Solvent-free coating systems typically add reactive diluents to reduce viscosity, but the addition of reactive diluents affects crosslinking density, thus affecting hardness and chemical resistance. Chinese patent (publication number CN 113174188 A) discloses a high-solids-content rust-free anti-corrosion coating for metals and its preparation method, which improves the anti-corrosion and wear-resistant properties of the coating through a combination of oil-soluble resins, functional ceramic fillers, and active small molecules, but still requires organic solvents, and the overall performance of the product needs further improvement. Chinese patent application (publication number CN121108843 A) discloses a multifunctional long-lasting anti-corrosion coating and its preparation method. It uses a high-activity epoxy resin and a flexible resin compounded together, combined with doped polyaniline, vapor phase rust inhibitor and benzotriazole rust inhibitor, and adds Es rust-preventive microcapsules to improve density, corrosion resistance and adhesion. However, the product is relatively brittle and its weather resistance needs to be further improved. Summary of the Invention

[0003] This invention provides a solvent-free and plasticizer-free sprayable metal anti-corrosion coating and its preparation method. By optimizing the combination and addition amount of modified polysiloxane resin, reactive diluent and other raw materials, the provided product achieves high solids and low viscosity, meeting the requirements of spraying construction while ensuring comprehensive performance such as adhesion and mechanical properties.

[0004] This invention provides a solvent-free, plasticizer-free sprayable metal anti-corrosion coating, which, by weight, comprises the following raw materials: 40-60 parts of polysiloxane resin, 30-50 parts of reactive diluent, 0.3-1 parts of epoxy silane coupling agent, 1-3 parts of amino silane coupling agent, 30-40 parts of silica powder, 0.15-0.4 parts of organotin, 1-3 parts of vinyltrimethoxysilane, 0.4-1.6 parts of anti-aging agent, 0.1-0.5 parts of polyamide wax, and 0.3-0.8 parts of organosilicon defoamer; wherein the active end group of the polysiloxane resin is alkoxysilyl, and the viscosity of the polysiloxane resin at 25°C is 2000-10000 mPa·s; and the active end group of the reactive diluent is alkoxysilyl, and the viscosity of the reactive diluent at 25°C is 100-200 mPa·s.

[0005] Based on a high-addition polysiloxane resin system, solvents were initially introduced to reduce viscosity in order to meet the requirements of spray coating applications. However, the solvent evaporation creates pores, leading to a decrease in adhesion and weather resistance. This invention further reduced viscosity by introducing plasticizers, but this resulted in a decrease in adhesion and chemical resistance. Through further investigation, this invention discovered that introducing an active diluent with an alkoxysilane-based active end group and a viscosity of 100-200 mPa·s at 25°C into a solvent-free coating system, combined with a polysiloxane resin with an active alkoxysilane-based active end group and a viscosity of 2000-10000 mPa·s at 25°C, ensures that the viscosity meets the requirements of spray coating applications at high solids content, effectively avoiding problems such as excessive hardness and reduced toughness, resulting in a product with good overall performance. The reasons for this may be as follows: By introducing low-viscosity small molecules with reactive alkoxysilane end groups, they can effectively interpenetrate between polymer chains, significantly reducing the initial viscosity of the system. When combined with medium-to-low viscosity polysiloxane resins (2000-10000 mPa·s), the molecular weight distribution and viscosity gradient of both are well matched, making them easy to flow and atomize under shear force (spraying), achieving sprayability with high solids content (low volatile organic compound content). Since both the reactive diluent and the resin have alkoxysilane end groups, they jointly participate in the hydrolysis-condensation reaction during the curing process. The reactive diluent, as a "flexible short segment," is introduced into the network, effectively balancing hardness and toughness. At the same time, the alkoxysilane groups react with the hydroxyl groups on the substrate surface to form strong Si-O-substrate chemical bonds, improving the overall performance.

[0006] In one embodiment, the raw materials for preparation, by weight, include: 50-55 parts of polysiloxane resin, 33-43 parts of reactive diluent, 0.5-0.8 parts of epoxy silane coupling agent, 1.5-2 parts of amino silane coupling agent, 35-38 parts of silica powder, 0.2-0.25 parts of organotin, 1.8-2 parts of vinyltrimethoxysilane, 1-1.2 parts of anti-aging agent, 0.2-0.3 parts of polyamide wax, and 0.5-0.6 parts of organosilicon defoamer.

[0007] In one embodiment, the polysiloxane resin has a viscosity (Brookfield, #2 shaft, 10 rpm) of 3000-5000 mPa.s at 25°C and is of the PolyHydrogen HP516 type.

[0008] In one embodiment, the modified polysiloxane reactive diluent is designated as Plihenghe HD200.

[0009] In one embodiment, the epoxy silane coupling agent includes at least one of 3-glycidyl etheroxypropyltrimethoxysilane, 3-glycidyl etheroxypropyltriethoxysilane, or 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane.

[0010] In one embodiment, the aminosilane coupling agent comprises N-β-aminoethyl-γ-aminopropyltrimethoxysilane and aminopolymer silane.

[0011] In one embodiment, the mass ratio of N-β-aminoethyl-γ-aminopropyltrimethoxysilane to amino polymer silane is 1-2:0.5-1.

[0012] In one embodiment, the mass ratio of N-β-aminoethyl-γ-aminopropyltrimethoxysilane to amino polymer silane is 1.2-1.5:0.5.

[0013] In one embodiment, the amino polymer silane is designated as Jianghan JH-AP1231.

[0014] This invention introduces epoxy silane coupling agents and amino silane coupling agents, particularly by simultaneously introducing 3-glycidyl etheroxypropyltrimethoxysilane, N-β-aminoethyl-γ-aminopropyltrimethoxysilane, and amino polymer silane, forming a "rigid" coupling agent. Flexible "Polymer-bridged" composite interface layer, in resin filler Strong and stable chemical bonds and physical entanglements are established between the substrates, thereby simultaneously improving adhesion, strength and toughness.

[0015] In one embodiment, the silicon micropowder has a particle size of 2000-3000 mesh.

[0016] In one embodiment, the silicon micropowder has a particle size of 2000 mesh and is of type GS2000, sourced from Jiangxi Guangyuan Chemical Co., Ltd.

[0017] Furthermore, this invention introduces silica micropowder with a particle size of 2000-3000 mesh, which condenses with the silane coupling agent in the system to form... Si O Si Key, reinforcing filler The resin interface bonding enhances the product's rigidity, hardness, wear resistance, and chemical resistance.

[0018] In one embodiment, the anti-aging agent includes UV-328 and UV-770.

[0019] In one embodiment, the mass ratio of UV-328 to UV-770 is 0.4-0.8:0.4-0.8.

[0020] In one embodiment, the mass ratio of UV-328 to UV-770 is 0.5-0.7:0.4-0.5.

[0021] This invention introduces UV-328 and UV-770 simultaneously, which quench free radicals and absorb ultraviolet rays respectively, to synergistically inhibit photoaging and ensure outdoor weather resistance.

[0022] In one embodiment, the organotin comprises dibutyltin dilaurate.

[0023] In one embodiment, the silicone defoamer is designated as BETTERSOL 4100 by Canghong Industrial.

[0024] In one embodiment, the polyamide wax is of the Arkema SLT type.

[0025] Another aspect of the present invention provides a method for preparing a solvent-free, plasticizer-free sprayable metal anti-corrosion coating, comprising the following steps: The polysiloxane resin, vinyltrimethoxysilane, anti-aging agent, epoxy silane coupling agent, polyamide wax, and reactive diluent are stirred and dispersed; filler is added and vacuum dispersed; organotin, aminosilane coupling agent, and defoamer are added and vacuum stirred, and after passing the test, they are filled.

[0026] In one embodiment, the stirring and dispersion conditions include: a scraping speed of 40-50 rpm, a dispersion disc speed of 200-300 rpm, and a time of 10-30 min.

[0027] In one embodiment, the vacuum dispersion conditions include: a wall scraping speed of 80-100 rpm, a dispersion disc speed of 800-1000 rpm, a time of 30-60 min, a temperature of 30-80℃, and a vacuum pressure of -0.1 MPa to -0.09 MPa.

[0028] In one embodiment, the vacuum stirring conditions include: a wall scraping speed of 60-70 rpm, a dispersion disc speed of 500-600 rpm, a time of 10-30 min, a temperature of 20-30℃, and a vacuum pressure of <-0.09 MPa.

[0029] Beneficial effects 1. This invention provides a solvent-free and plasticizer-free sprayable metal anti-corrosion coating and its preparation method. By optimizing the combination and addition amount of modified polysiloxane resin, reactive diluent and other raw materials, the provided product achieves high solids and low viscosity, meeting the requirements of spraying construction while ensuring comprehensive performance such as adhesion and mechanical properties.

[0030] 2. This invention introduces an active diluent with an active end group of alkoxysilane with a viscosity of 100-200 mPa·s at 25°C into a solvent-free coating system, combined with a polysiloxane resin with an active end group of alkoxysilane with a viscosity of 2000-10000 mPa·s at 25°C. This ensures that the viscosity of the product meets the requirements of spraying applications at high solids content, and effectively avoids the problems of excessive hardness and reduced toughness. The product has good overall performance.

[0031] 3. This invention introduces epoxy silane coupling agents and amino silane coupling agents, especially simultaneously introducing 3-glycidyl etheroxypropyltrimethoxysilane, N-β-aminoethyl-γ-aminopropyltrimethoxysilane, and amino polymer silane, forming a "rigid" coupling agent. Flexible "Polymer-bridged" composite interface layer, in resin filler Strong and stable chemical bonds and physical entanglements are established between the substrates, thereby simultaneously improving adhesion, strength and toughness.

[0032] 4. This invention introduces silica micropowder with a particle size of 2000-3000 mesh, which condenses with the silane coupling agent in the system to form... Si O Si Key, reinforcing filler The resin interface bonding enhances the product's rigidity, hardness, wear resistance, and chemical resistance.

[0033] 5. This invention introduces UV-328 and UV-770 simultaneously, which quench free radicals and absorb ultraviolet rays respectively, synergistically inhibiting photoaging and ensuring outdoor weather resistance. Detailed Implementation

[0034] The types of raw materials used in Examples 1-2 and Comparative Examples 1-14 of this invention are shown in Table 1.

[0035] Table 1

[0036] Examples 1-2, Comparative Examples 1-9 Examples 1-2 and Comparative Examples 1-9 of the present invention provide a solvent-free and plasticizer-free sprayable metal anti-corrosion coating, the formulation of which is shown in Tables 2 and 3 by weight.

[0037] Table 2

[0038] Table 3

[0039] Examples 1-2 and Comparative Examples 1-9 of the present invention provide a method for preparing a solvent-free and plasticizer-free sprayable metal anti-corrosion coating, comprising the following steps: Polysiloxane resin, vinyltrimethoxysilane, anti-aging agent, epoxy silane coupling agent, polyamide wax, and reactive diluent are stirred and dispersed (in Comparative Example 2, a solvent is also added in this step, and in Comparative Example 3, a plasticizer is also added in this step); filler is added and vacuum dispersed; organotin, aminosilane coupling agent, and defoamer are added and vacuum stirred, and after passing the test, they are filled.

[0040] The stirring and dispersion conditions include: a wall scraping speed of 50 rpm, a dispersion disc speed of 300 rpm, and a time of 10 min.

[0041] The conditions for vacuum dispersion include: a wall scraping speed of 100 rpm, a dispersion disc speed of 800 rpm, a time of 30 min, a temperature of 50 °C, and a vacuum pressure of -0.1 MPa.

[0042] The conditions for vacuum stirring include: wall scraping speed of 70 rpm, dispersion disk speed of 500 rpm, time of 10 min, temperature of 25℃, and vacuum pressure of -0.1 MPa.

[0043] Performance testing methods The products provided in each embodiment and comparative example of this application were subjected to the tests shown in Table 4. The test results are shown in Tables 5 and 6.

[0044] Table 4

[0045] Table 5

[0046] Table 6

[0047] Analysis of the data in Tables 5 and 6 shows that the products provided in Examples 1-2 have better overall performance than those in Comparative Examples 1-9, and better meet the needs of practical applications.

Claims

1. A solvent-free, plasticizer-free sprayable anti-corrosion coating for metals, characterized in that, The raw materials for preparing the metal anti-corrosion coating, by weight, include: 40-60 parts of polysiloxane resin, 30-50 parts of reactive diluent, 0.3-1 parts of epoxy silane coupling agent, 1-3 parts of amino silane coupling agent, 30-40 parts of silica powder, 0.15-0.4 parts of organotin, 1-3 parts of vinyltrimethoxysilane, 0.4-1.6 parts of anti-aging agent, 0.1-0.5 parts of polyamide wax, and 0.3-0.8 parts of organosilicon defoamer. The active end group of the polysiloxane resin is alkoxysilane, and the viscosity of the polysiloxane resin at 25°C is 2000-10000 mPa·s; the active end group of the reactive diluent is alkoxysilane, and the viscosity of the reactive diluent at 25°C is 100-200 mPa·s.

2. The solvent-free, plasticizer-free sprayable metal anti-corrosion coating according to claim 1, characterized in that, The raw materials for preparing the metal anti-corrosion coating, by weight, include: 50-55 parts of polysiloxane resin, 33-43 parts of reactive diluent, 0.5-0.8 parts of epoxy silane coupling agent, 1.5-2 parts of amino silane coupling agent, 35-38 parts of silica powder, 0.2-0.25 parts of organotin, 1.8-2 parts of vinyltrimethoxysilane, 1-1.2 parts of anti-aging agent, 0.2-0.3 parts of polyamide wax, and 0.5-0.6 parts of organosilicon defoamer.

3. The solvent-free, plasticizer-free sprayable metal anti-corrosion coating according to claim 1, characterized in that, The epoxy silane coupling agent includes at least one of 3-glycidyl etheroxypropyltrimethoxysilane, 3-glycidyl etheroxypropyltriethoxysilane, or 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane.

4. The solvent-free, plasticizer-free sprayable metal anti-corrosion coating according to claim 1, characterized in that, The aminosilane coupling agent includes N-β-aminoethyl-γ-aminopropyltrimethoxysilane and amino polymer silane.

5. The solvent-free, plasticizer-free sprayable metal anti-corrosion coating according to claim 3, characterized in that, The mass ratio of N-β-aminoethyl-γ-aminopropyltrimethoxysilane to amino polymer silane is 1-2:0.5-1.

6. The solvent-free, plasticizer-free sprayable metal anti-corrosion coating according to claim 1, characterized in that, The particle size of the silicon micro powder is 2000-3000 mesh.

7. The solvent-free, plasticizer-free sprayable metal anti-corrosion coating according to claim 1, characterized in that, The anti-aging agents include UV-328 and UV-770.

8. The solvent-free, plasticizer-free sprayable metal anti-corrosion coating according to claim 7, characterized in that, The mass ratio of UV-328 to UV-770 is 0.4-0.8:0.4-0.

8.

9. The solvent-free, plasticizer-free sprayable metal anti-corrosion coating according to claim 1, characterized in that, The organotin includes dibutyltin dilaurate.

10. A method for preparing a solvent-free, plasticizer-free sprayable metal anti-corrosion coating according to any one of claims 1-9, characterized in that, Includes the following steps: The polysiloxane resin, vinyltrimethoxysilane, anti-aging agent, epoxy silane coupling agent, polyamide wax, and reactive diluent are stirred and dispersed; filler is added and vacuum dispersed; organotin, aminosilane coupling agent, and defoamer are added and vacuum stirred, and after passing the test, they are filled.

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