Anticorrosive solventless coating and method for preparing the same

Abstract

The application discloses a kind of anticorrosive solvent-free paint and preparation method thereof, it is related to anticorrosive paint technical field.The application is prepared polyurethane first with octahydro-4,7-methyl-1H-methylene diisocyanate and polyol crosslinking;When the two isocyanate of octahydro-4,7-methyl-1H-methylene diisocyanate and polyol crosslinking, three-dimensional network structure can be formed, and the spacing and arrangement between each other of hydrophobic branched chain that can orderly stretch to surface are favorable to prevent water molecules from entering, effectively improve the water resistance of coating;Then utilize nano silicon dioxide to load methyl benzotriazole as anticorrosive agent;When coating solidification, with chemical reaction and the change of coating structure, methyl benzotriazole will be released and dispersed into coating, further fill the tiny pore in coating, and can more directly with the active site of metal surface interact, improve anticorrosive efficiency.The anticorrosive solvent-free paint prepared by the application has the effect of water resistance, anticorrosion.

Description

Technical Field

[0001] This invention relates to the field of anti-corrosion coatings, specifically to an anti-corrosion solvent-free coating and its preparation method. Background Technology

[0002] Paint, traditionally known as varnish in China, is a viscous liquid applied to the surface of an object to be protected or decorated, forming a continuous, firmly adhering film. It is typically made primarily of resin, oil, or emulsion, with or without pigments and fillers, and with appropriate additives, and is prepared using organic solvents or water.

[0003] Therefore, the development of anti-corrosion solvent-free coatings is of great significance for protecting human health. Summary of the Invention

[0004] The purpose of this invention is to provide a corrosion-resistant solvent-free coating and its preparation method, so as to solve the problems existing in the prior art.

[0005] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a corrosion-resistant solvent-free coating, comprising a first component and a second component.

[0006] The first component comprises the following components in parts by weight: 45-60 parts of polyol, 5-15 parts of functional additives, 30-45 parts of filler, 10-15 parts of epoxy resin, 10-20 parts of thermosetting polyacrylate, and 0.5-3 parts of anti-corrosion additives.

[0007] The second component comprises the following components in parts by weight: 26 to 58 parts of octahydro-4,7-methyl-1H-methylene diisocyanate prepolymer;

[0008] The corrosion inhibitor is nano-silica loaded with methylbenzotriazole.

[0009] Furthermore, the polyol includes one or more of polyester diols, polyether diols, and polyether triols.

[0010] Furthermore, the functional additives include one or more of dispersants, defoamers, and leveling agents.

[0011] Furthermore, the dispersant includes one or more of fatty acids, DY-9006, or metal soap dispersants; the defoamer is one or more of silicone defoamers, higher alcohol defoamers, and polyether defoamers; and the leveling agent is one or more of acrylic leveling agents, silicone leveling agents, and fluorocarbon leveling agents.

[0012] Furthermore, the filler is one or more of bentonite, titanium dioxide, and barium sulfate.

[0013] Furthermore, the epoxy resin is one or more of bisphenol A type epoxy resin and bisphenol F type epoxy resin.

[0014] Furthermore, the preparation method of the octahydro-4,7-methyl-1H-methylene diisocyanate prepolymer includes the following steps:

[0015] A. Dehydrate the polyol at 130-140 Pa and 110-120 °C for 1-3 h to obtain dehydrated polyol; B. Mix the dehydrated polyol with octahydro-4,7-methyl-1H-methylene diisocyanate at a molar ratio of 1:2-4 and react at 200 r / min and 80 °C for 2-3 h.

[0016] Furthermore, the preparation method of the preservative additive includes the following preparation steps:

[0017] a) Place nano-silica in a microwave oven and heat on high (800W) for 3-5 minutes, then cool to room temperature to obtain activated nano-silica; b) Dissolve methylbenzotriazole in ethanol at 4-6 times the mass of methylbenzotriazole, add activated nano-silica at 3-5 times the mass of methylbenzotriazole, sonicate at 200W for 4-6 hours, filter, and dry to obtain the preservative additive.

[0018] Furthermore, the particle size of the nano-silica is 50~80nm.

[0019] Furthermore, the preparation method of the anti-corrosion solvent-free coating includes the following preparation steps: mixing the first component and the second component according to the weight ratio, mixing evenly, filtering and discharging to obtain the anti-corrosion solvent-free coating.

[0020] Compared with the prior art, the beneficial effects achieved by the present invention are:

[0021] This invention first prepares a solvent-free polyurethane coating by crosslinking octahydro-4,7-methyl-1H-methylene diisocyanate and polyol, and then adds a nano-silica preservative loaded with methylbenzotriazole to obtain a corrosion-resistant solvent-free coating, so as to achieve the effects of water resistance and corrosion prevention.

[0022] First, polyurethane was prepared by crosslinking octahydro-4,7-methyl-1H-methylene diisocyanate with a polyol. When the two isocyanates of octahydro-4,7-methyl-1H-methylene diisocyanate crosslink with the polyol, they form a three-dimensional network structure. This crosslinking structure helps to improve the strength and stability of the polyurethane coating. At the same time, the hydrophobic branches can extend to the surface in an orderly manner, and the spacing and arrangement between them help to prevent water molecules from entering, forming a structure similar to a hydrophobic layer. This effectively improves the water resistance of the coating, prevents water from penetrating into the interior of the coating, protects the coated object from water erosion, and the hydrophobic layer can also act as a barrier to reduce the damage of corrosive chemicals to the coating and the coated object, thereby improving the corrosion resistance of the coating.

[0023] Secondly, methylbenzotriazole loaded with nano-silica is used as a corrosion inhibitor. The nano-silica particles fill the pores of the polyurethane coating, increasing the density of the coating and forming a physical barrier to prevent corrosive substances such as moisture, oxygen, acids, and alkalis from penetrating into the coating, thus protecting the coated object from corrosion. During the curing of the solvent-free polyurethane coating, the interaction between methylbenzotriazole and nano-silica weakens or is even destroyed due to the chemical reaction and changes in the coating structure. Methylbenzotriazole is released and dispersed into the coating, further filling the micropores in the coating and interacting more directly with the active sites on the metal surface, improving the corrosion protection efficiency. Especially in areas with micro-defects or where nano-silica is difficult to cover, it compensates for the lack of corrosion protection. Nano-silica has a large specific surface area and surface activity, which can adsorb more methylbenzotriazole molecules, causing them to be slowly released on the metal surface and prolonging the corrosion protection time. Detailed Implementation

[0024] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0025] To more clearly illustrate the method provided by the present invention, the following embodiments are provided in detail. The test methods for various indicators of the anti-corrosion solvent-free coatings prepared in the following embodiments are as follows:

[0026] Hardness: The coatings of the anti-corrosion solvent-free coatings prepared by the same mass of the examples and comparative examples were cured and their hardness was tested according to GB / T 6739-2006 standard "Determination of Hardness of Paint Film by Pencil Method".

[0027] Water resistance: The cured coatings of the anti-corrosion solvent-free coatings prepared in the same mass as those in the examples and comparative examples were placed in water for 200 hours, and the presence of blistering, peeling and discoloration was observed.

[0028] Salt spray resistance: The coatings of the anti-corrosion solvent-free coatings prepared by the same mass of the examples and comparative examples were cured and their salt spray resistance was tested according to GB / T 1771-1991 "Determination of resistance to neutral salt spray of paints and varnishes".

[0029] Chemical corrosion resistance: The cured coatings of the anti-corrosion solvent-free coatings prepared in the same mass as those in the examples and comparative examples were placed in a mixture of 10wt% sulfuric acid, 30wt% sodium chloride, 30wt% sodium hydroxide and No. 2 diesel oil for 30 days, and the presence of damage or corrosion was observed.

[0030] Example 1

[0031] A method for preparing a corrosion-resistant solvent-free coating includes the following preparation steps:

[0032] (1) Preparation of octahydro-4,7-methyl-1H-methylene diisocyanate prepolymer:

[0033] A. Polycaprolactone diol was dehydrated at 130 Pa and 110 °C for 2 h to obtain dehydrated polycaprolactone diol; B. Dehydrated polycaprolactone diol was mixed with octahydro-4,7-methyl-1H-methylene diisocyanate at a molar ratio of 1:2 and reacted at 200 r / min and 80 °C for 2 h.

[0034] (2) Preparation of preservatives:

[0035] a) Place nano-silica in a microwave oven and heat on high for 3 minutes at 800W. Cool to room temperature to obtain activated nano-silica. b) Dissolve methylbenzotriazole in ethanol at 4 times the mass of methylbenzotriazole, add activated nano-silica at 3 times the mass of methylbenzotriazole, sonicate at 200W for 4 hours, filter, and dry to obtain the preservative additive.

[0036] (3) Mix the first component and the second component according to the weight ratio, and after mixing evenly, filter the material to obtain a solvent-free anti-corrosion coating; the first component includes: 45 parts of polycaprolactone diol, 2 parts of polydimethylsiloxane, 2 parts of polybutyl acrylate, 1 part of DY-9006, 30 parts of bentonite, 10 parts of bisphenol A epoxy resin, 10 parts of thermosetting polyacrylate, and 0.5 parts of anti-corrosion additive; the second component includes: 42 parts of octahydro-4,7-methyl-1H-methylene diisocyanate prepolymer.

[0037] Example 2

[0038] A method for preparing a corrosion-resistant solvent-free coating includes the following preparation steps:

[0039] (1) Preparation of octahydro-4,7-methyl-1H-methylene diisocyanate prepolymer:

[0040] A. Polycaprolactone diol was dehydrated at 135 Pa and 115 °C for 2 h to obtain dehydrated polycaprolactone diol; B. Dehydrated polycaprolactone diol was mixed with octahydro-4,7-methyl-1H-methylene diisocyanate at a molar ratio of 1:3 and reacted at 200 r / min and 80 °C for 2.5 h.

[0041] (2) Preparation of preservatives:

[0042] a) Place nano-silica in a microwave oven and heat on high for 4 minutes at 800W. Cool to room temperature to obtain activated nano-silica. b) Dissolve methylbenzotriazole in ethanol at 5 times the mass of methylbenzotriazole, add activated nano-silica at 4 times the mass of methylbenzotriazole, sonicate at 200W for 5 hours, filter, and dry to obtain the preservative additive.

[0043] (3) Mix the first component and the second component according to the weight ratio, and after mixing evenly, filter the material to obtain a corrosion-resistant solvent-free coating; the first component includes: 55 parts of polycaprolactone diol, 5 parts of polydimethylsiloxane, 3 parts of polybutyl acrylate, 2 parts of DY-9006, 35 parts of bentonite, 13 parts of bisphenol A epoxy resin, 15 parts of thermosetting polyacrylate, and 2 parts of corrosion inhibitor; the second component includes: 48 parts of octahydro-4,7-methyl-1H-methylene diisocyanate prepolymer.

[0044] The problem in Example 3 is as described above.

[0045] A method for preparing a corrosion-resistant solvent-free coating includes the following preparation steps:

[0046] (1) Preparation of octahydro-4,7-methyl-1H-methylene diisocyanate prepolymer:

[0047] A. Polycaprolactone diol was dehydrated at 140 Pa and 120 °C for 3 h to obtain dehydrated polycaprolactone diol; B. Dehydrated polycaprolactone diol was mixed with octahydro-4,7-methyl-1H-methylene diisocyanate at a molar ratio of 1:4 and reacted at 200 r / min and 80 °C for 3 h.

[0048] (2) Preparation of preservatives:

[0049] a) Place nano-silica in a microwave oven and heat on high for 5 minutes at 800W. Cool to room temperature to obtain activated nano-silica. b) Dissolve methylbenzotriazole in ethanol at 6 times the mass of methylbenzotriazole, add activated nano-silica at 5 times the mass of methylbenzotriazole, sonicate at 200W for 6 hours, filter, and dry to obtain the preservative additive.

[0050] (3) Mix the first component and the second component according to the weight ratio, and after mixing evenly, filter the material to obtain a corrosion-resistant solvent-free coating; the first component includes: 60 parts of polycaprolactone diol, 5 parts of polydimethylsiloxane, 5 parts of polybutyl acrylate, 5 parts of DY-9006, 45 parts of bentonite, 15 parts of bisphenol A epoxy resin, 20 parts of thermosetting polyacrylate, and 3 parts of corrosion inhibitor; the second component includes: 58 parts of octahydro-4,7-methyl-1H-methylene diisocyanate prepolymer.

[0051] Comparative Example 1

[0052] The difference between Comparative Example 1 and Example 2 is that step (1) is different. Step (1) is changed to: dehydrating polycaprolactone diol at 135 Pa and 115 °C for 2 h to obtain dehydrated polycaprolactone diol; B. mixing dehydrated polycaprolactone diol and toluene diisocyanate at a molar ratio of 1:3 and reacting at 200 r / min and 80 °C for 2.5 h to obtain toluene diisocyanate prepolymer; Step (3) is changed to: mixing the first component and the second component according to the weight ratio, filtering after uniform mixing to obtain anti-corrosion solvent-free coating; The first component includes: 55 parts of polycaprolactone diol, 5 parts of polydimethylsiloxane, 3 parts of polybutyl acrylate, 2 parts of DY-9006, 35 parts of bentonite, 13 parts of bisphenol A epoxy resin, 15 parts of thermosetting polyacrylate, and 2 parts of anti-corrosion additive; The second component includes: 48 parts of toluene diisocyanate prepolymer; The remaining steps are the same as in Example 2.

[0053] Comparative Example 2

[0054] The difference between Comparative Example 2 and Example 2 is that step (1) is omitted, and step (3) is changed to: mixing the first component and the second component according to the weight ratio, filtering the mixture after uniform mixing, and obtaining a corrosion-resistant solvent-free coating; the first component includes: 55 parts of polycaprolactone diol, 5 parts of polydimethylsiloxane, 3 parts of polybutyl acrylate, 2 parts of DY-9006, 35 parts of bentonite, 13 parts of bisphenol A epoxy resin, 15 parts of thermosetting polyacrylate, and 2 parts of corrosion inhibitor; the second component includes: 48 parts of octahydro-4,7-methyl-1H-methylene diisocyanate; the remaining steps are the same as in Example 2.

[0055] Comparative Example 3

[0056] The difference between Comparative Example 3 and Example 2 is that step (2) is omitted, and step (3) is changed to: mixing the first component and the second component according to the weight ratio, filtering the mixture after uniform mixing, and obtaining a corrosion-resistant solvent-free coating; the first component includes: 55 parts of polycaprolactone diol, 5 parts of polydimethylsiloxane, 3 parts of polybutyl acrylate, 2 parts of DY-9006, 35 parts of bentonite, 13 parts of bisphenol A epoxy resin, 15 parts of thermosetting polyacrylate, and 2 parts of methylbenzotriazole; the second component includes: 48 parts of octahydro-4,7-methyl-1H-methylene diisocyanate prepolymer; the remaining steps are the same as in Example 2.

[0057] Comparative Example 4

[0058] The difference between Comparative Example 4 and Example 2 is that step (2) is omitted, and step (3) is changed to: mixing the first component and the second component according to the weight ratio, filtering the mixture after uniform mixing, and obtaining a corrosion-resistant solvent-free coating; the first component includes: 55 parts of polycaprolactone diol, 5 parts of polydimethylsiloxane, 3 parts of polybutyl acrylate, 2 parts of DY-9006, 35 parts of bentonite, 13 parts of bisphenol A epoxy resin, 15 parts of thermosetting polyacrylate, and 2 parts of nano silica; the second component includes: 48 parts of octahydro-4,7-methyl-1H-methylene diisocyanate prepolymer; the remaining steps are the same as in Example 2.

[0059] Comparative Example 5

[0060] The difference between Comparative Example 5 and Example 2 is that step (2) is omitted, and step (3) is changed to: mixing the first component and the second component according to the weight ratio, filtering the mixture after uniform mixing, and obtaining a corrosion-resistant solvent-free coating; the first component includes: 55 parts of polycaprolactone diol, 5 parts of polydimethylsiloxane, 3 parts of polybutyl acrylate, 2 parts of DY-9006, 35 parts of bentonite, 13 parts of bisphenol A epoxy resin, and 15 parts of thermosetting polyacrylate; the second component includes: 48 parts of octahydro-4,7-methyl-1H-methylene diisocyanate prepolymer; the remaining steps are the same as in Example 2.

[0061] Comparative Example 6

[0062] The difference between Comparative Example 6 and Example 2 is that step (2) is omitted, and step (3) is changed to: mixing the first component and the second component according to the weight ratio, filtering the mixture after uniform mixing, and obtaining a corrosion-resistant solvent-free coating; the first component includes: 55 parts of polycaprolactone diol; 5 parts of polydimethylsiloxane; 3 parts of polybutyl acrylate; 2 parts of DY-9006; 35 parts of bentonite; 13 parts of bisphenol A epoxy resin; 15 parts of thermosetting polyacrylate; 1 part of nano silica; and 1 part of methylbenzotriazole; the second component includes: 48 parts of octahydro-4,7-methyl-1H-methylene diisocyanate prepolymer; the remaining steps are the same as in Example 2.

[0063] Comparative Example 7

[0064] The difference between Comparative Example 1 and Example 2 is that step (2) is different. Step (2) is changed to: dissolving methylbenzotriazole in ethanol at 5 times the mass of methylbenzotriazole, adding nano-silica at 4 times the mass of methylbenzotriazole, ultrasonically vibrating at 200W for 5 hours, filtering, and drying to obtain the preservative additive; the remaining steps are the same as in Example 2.

[0065] Example of effect

[0066] Table 1 below shows the performance analysis results of the anti-corrosion solvent-free coatings of Examples 1 to 3 and Comparative Examples 1 to 7 of the present invention.

[0067] Table 1

[0068]

[0069] A comparison of the experimental data from Example 2 with Comparative Examples 1 and 2 reveals that the present invention uses octahydro-4,7-methyl-1H-methylene diisocyanate and polyol crosslinking to prepare polyurethane. When the two isocyanates of octahydro-4,7-methyl-1H-methylene diisocyanate crosslink with the polyol, they form a three-dimensional network structure. This crosslinking structure helps improve the strength and stability of the polyurethane coating. Simultaneously, the hydrophobic branches can extend orderly to the surface, and their spacing and arrangement help prevent water molecules from entering, forming a structure similar to a hydrophobic layer. This effectively improves the water resistance of the coating, prevents moisture from penetrating into the coating interior, protects the coated object from water erosion, and the hydrophobic layer can act as a barrier, reducing the damage of corrosive chemicals to the coating and the coated object, thus improving the coating's corrosion resistance. A comparison of the experimental data from Example 2 with Comparative Examples 3, 4, 5, and 6 reveals that using nano-silica loaded with methylbenzotriazole as a preservative; nano-silica... Silica particles fill the pores of the polyurethane coating, increasing its density and forming a physical barrier that prevents corrosive substances such as moisture, oxygen, acids, and alkalis from penetrating into the coating, thus protecting the coated object from corrosion. During the curing of the solvent-free polyurethane coating, the interaction between methylbenzotriazole and nano-silica weakens or is even destroyed due to chemical reactions and changes in the coating structure. Methylbenzotriazole is released and dispersed into the coating, further filling the micropores and interacting more directly with active sites on the metal surface, improving corrosion resistance, especially in areas with micro-defects or where nano-silica is difficult to cover, thus compensating for insufficient corrosion protection. Nano-silica has a large specific surface area and surface activity, enabling it to adsorb more methylbenzotriazole molecules, causing them to be slowly released onto the metal surface and prolonging the corrosion protection time. A comparison of experimental data from Example 2 and Comparative Example 7 shows that activated nano-silica is more conducive to the adsorption of methylbenzotriazole.

[0070] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No markings in the claims should be construed as limiting the scope of the claims.

Claims

1. A solvent-free anti-corrosion coating, comprising a first component and a second component, characterized in that, The first component comprises the following components in parts by weight: 45-60 parts of polyol, 5-15 parts of functional additives, 30-45 parts of filler, 10-15 parts of epoxy resin, 10-20 parts of thermosetting polyacrylate, and 0.5-3 parts of anti-corrosion additives. The second component comprises the following components in parts by weight: 26 to 58 parts of octahydro-4,7-methyl-1H-methylene diisocyanate prepolymer; The corrosion inhibitor is nano-silica loaded with methylbenzotriazole; The octahydro-4,7-methyl-1H-methylene diisocyanate prepolymer was prepared by the following steps: A. Dehydrate the polyol at 130-140 Pa and 110-120 °C for 1-3 h to obtain the dehydrated polyol; B. Mix the dehydrated polyol with octahydro-4,7-methyl-1H-methylene diisocyanate at a molar ratio of 1:2-4 and react at 200 r / min and 80 °C for 2-3 h. The preservative agent is prepared by the following steps: a) Place nano-silica in a microwave oven and heat on high for 3-5 minutes at 800W, then cool to room temperature to obtain activated nano-silica; b) Dissolve methylbenzotriazole in ethanol at 4-6 times the mass of methylbenzotriazole, add activated nano-silica at 3-5 times the mass of methylbenzotriazole, sonicate at 200W for 4-6 hours, filter, and dry to obtain the preservative additive. The functional additives include one or more of dispersants, defoamers, and leveling agents.

2. The anti-corrosion solvent-free coating according to claim 1, characterized in that, The polyols include one or more of polyester diols, polyether diols, and polyether triols.

3. The anti-corrosion solvent-free coating according to claim 1, characterized in that, The dispersant includes one or more of fatty acids, DY-9006, or metal soap dispersants; the defoamer is one or more of silicone defoamers, higher alcohol defoamers, and polyether defoamers; and the leveling agent is one or more of acrylic leveling agents, silicone leveling agents, and fluorocarbon leveling agents.

4. The anti-corrosion solvent-free coating according to claim 1, characterized in that, The filler is one or more of bentonite, titanium dioxide, and barium sulfate.

5. The anti-corrosion solvent-free coating according to claim 1, characterized in that, The epoxy resin is one or more of bisphenol A type epoxy resin and bisphenol F type epoxy resin.

6. The anti-corrosion solvent-free coating according to claim 5, characterized in that, The particle size of the nano-silica is 50~80nm.

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