A solvent-resistant zinc spraying coating without sealing, a preparation method and application thereof

Abstract

The application relates to the technical field of paint chemistry, and provides a preparation method of a solvent-resistant zinc spraying paint without sealing, which comprises the following steps: sequentially adding resins and a first solvent into a reaction kettle, dehydrating while stirring and heating, observing a water segregator until no water is separated from the water segregator, and cooling to room temperature; sequentially adding a catalyst and a curing agent into the reaction kettle, stirring while heating to a first temperature, keeping the first temperature for a certain time, then heating to a second temperature, keeping the second temperature for a certain time, stopping the reaction, and cooling to room temperature; filtering to obtain a self-crosslinking resin; pouring a second solvent, an additive and a dispersant into a dispersing machine, rotating the dispersing machine at a preset rotating speed until the second solvent, the additive and the dispersant are uniformly mixed, slowly pouring zinc powder into the dispersing machine, adjusting the rotating speed of the dispersing machine, reacting for a certain time, and filtering to obtain a resin-free zinc slurry; and mixing the self-crosslinking resin and the resin-free zinc slurry according to a certain proportion to obtain the solvent-resistant zinc spraying paint without sealing. The application further discloses the solvent-resistant zinc spraying paint without sealing and an application thereof.

Description

Technical Field

[0001] This invention belongs to the field of coating chemistry technology, and particularly relates to a solvent-resistant zinc spray coating that does not require sealing, its preparation method, and its application. Background Technology

[0002] Currently, cold-coated zinc is a single-component coating, mainly composed of high-purity zinc powder, flux, and a special organic mixed resin. The zinc content in the dry film of the coating exceeds 96%, possessing the dual advantages of hot-dip galvanizing and zinc-rich coatings. Cold-coated zinc achieves the effects of hot-dip galvanizing and thermal spraying zinc by being applied and cured at room temperature, providing long-lasting cathodic protection and physical shielding. Cold-coated zinc offers excellent corrosion resistance and is easy to apply. In recent years, as a new type of anti-corrosion coating for the bridge and petrochemical industries, cold-coated zinc has been increasingly adopted by design institutes and applied in steel structure bridges, ships, and petrochemical industries. Cold-coated zinc is simpler, more convenient, more environmentally friendly, and consumes less energy than thermal spraying zinc or hot-dip galvanizing during application.

[0003] During construction, workers discovered that cold-coated zinc has high application requirements, with varying degrees of problems in terms of workability and compatibility. A single coat is difficult to achieve an 80μm thickness without sagging. The film-forming substances in single-component cold-coated zinc coatings are mostly thermoplastic resins with very poor solvent resistance. If a sealing paint is not applied over the cold-coated zinc layer, and a two-component epoxy micaceous iron oxide intermediate paint or epoxy thick-film intermediate paint is sprayed directly, serious construction quality issues such as coating adhesion loss, peeling, and significant reduction in adhesion will occur. The traditional solution is to spray a thin layer of two-component sealing paint over the cold-coated zinc layer. This method is difficult to control film thickness and has the potential for missed or overspraying, posing a certain risk to construction quality. For steel structure corners and complex structural components, incomplete sealing may occur, leading to adhesion loss and other quality issues. The thin-spray sealing process requires changing the dilution ratio and adding more organic solvents, increasing the amount of volatile organic solvents. The thin-spray sealing process causes environmental pollution, harms the health of construction workers, and increases material and labor costs, as well as extending the construction period.

[0004] To solve the above-mentioned technical problems, this invention designs a solvent-resistant zinc spray coating that does not require sealing, its preparation method, and its application. Summary of the Invention

[0005] This invention provides a solvent-resistant, non-sealing zinc spray coating, its preparation method, and its application. It aims to solve the following quality problems in cold zinc coating: undercoat biting and peeling between coating systems; poor solvent resistance of the coating, which leads to dissolution and a sharp decline in adhesion; and the problem of incompatibility with intermediate coatings and 70-90μm sag of single-coat layers when no sealing paint is applied during cold zinc coating.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a method for preparing a solvent-resistant zinc spray coating without sealing, comprising the following steps: adding resin and a first solvent sequentially to a reaction vessel, stirring and heating to dehydrate, observing the water separator until no water is removed from the water separator, and cooling to room temperature; adding a catalyst and a curing agent sequentially to the reaction vessel, stirring and heating to a first temperature and holding for a certain time, then heating to a second temperature and holding for a certain time, terminating the reaction and cooling to room temperature, filtering to obtain a self-crosslinking resin; dispersing the second solvent, additives, and dispersant in a disperser, rotating the disperser at a preset speed until uniform mixing, slowly pouring in zinc powder, adjusting the disperser speed and reacting for a certain time, filtering to obtain a resin-free zinc paste; mixing the self-crosslinking resin and the resin-free zinc paste in a certain proportion to obtain a solvent-resistant zinc spray coating without sealing.

[0007] Based on the above technical solution, the resin is one or more of polycarbonate polyol, polyether polyol, polyether ester polyol, trifunctional polyol, and polyfunctional polyol.

[0008] Based on the above technical solution, the first solvent is one or more of xylene, trimethylbenzene, and butyl acetate.

[0009] Based on the above technical solution, the catalyst is one or more of ferric chloride, zinc naphthenate, and organic bismuth.

[0010] Based on the above technical solution, the curing agent is one or more of carbodiimide-urea ketimide modified 4,4'-diphenylmethane diisocyanate and polymethyl polyphenyl isocyanate.

[0011] Based on the above technical solution, the second solvent is one or more of xylene, trimethylbenzene, methyl acetal, solvent oil, ethyl acetate, and butyl acetate.

[0012] Based on the above technical solution, the additive is an anti-settling additive or a rheology modifier. The anti-settling additive is one or more of organic bentonite, fumed silica, polyamide wax, and ultrafine silica. The rheology modifier is one or more of modified polyamide wax paste, modified urea solution rheology modifier, and polyurea anti-settling agent.

[0013] Based on the above technical solution, the dispersant is one or more of polyether, polyurethane, and polyester dispersants.

[0014] Based on the above technical solution, the mixing ratio of self-crosslinking resin and resin-free zinc paste is (7~9):1.

[0015] Secondly, the present invention provides a solvent-resistant zinc spraying coating that does not require sealing, which is prepared according to the preparation method of the solvent-resistant zinc spraying coating described in any of the above embodiments.

[0016] Thirdly, the present invention provides the application of the solvent-resistant zinc spraying coating prepared by the method of preparing the solvent-resistant zinc spraying coating according to any one of the above embodiments in civil engineering and building engineering.

[0017] Compared with related technologies, the beneficial effects of the present invention are as follows: This invention first prepares a self-crosslinking resin, a high-molecular polymer material that, during film formation or curing, requires no additional coupling agents, curing agents, or other special additives. It can undergo crosslinking and curing reactions with oxygen and moisture in the air at room temperature. After curing, the polymer chains can self-crosslink to form a three-dimensional network structure. The self-crosslinking resin itself exhibits excellent resistance to neutral salt spray and xylene solvents. These characteristics of the self-crosslinking resin result in a solvent-resistant zinc spray coating that exhibits higher chemical corrosion resistance, excellent solvent resistance, and good compatibility with various commercially available epoxy intermediate paints. Furthermore, its excellent flexibility ensures that the paint film does not crack or peel after drying and curing, and it maintains excellent adhesion to the substrate. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only one embodiment of the present invention. For those skilled in the art, other embodiments can be derived from the provided drawings without creative effort.

[0019] Figure 1 This is a flowchart of a method for preparing a solvent-resistant zinc spray coating that does not require sealing, provided by the present invention. Detailed Implementation

[0020] 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 skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] Unless otherwise defined, all technical and scientific terms used in this specification have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention. The term "and / or" as used in this specification includes any and all combinations of one or more of the associated listed items.

[0022] Unless otherwise specified, the experimental methods used in the following examples are conventional methods; unless otherwise specified, the reagents, materials, instruments, etc. used in the following examples are all commercially available.

[0023] Combination Figure 1 As shown, the present invention provides a method for preparing a solvent-resistant zinc spray coating that does not require sealing, comprising the following steps: S101, add the resin and the first solvent to the reactor in sequence, stir and heat up to dehydrate, observe the water separator until no water is removed from the water separator, and cool to room temperature; S102, add catalyst and curing agent to the reactor in sequence, heat to the first temperature while stirring and hold for a certain time, then heat to the second temperature and hold for a certain time, terminate the reaction and cool to room temperature, filter to obtain self-crosslinking resin; S103, the second solvent, additives and dispersant are poured into a disperser and dispersed. The disperser is rotated at a preset speed until the mixture is uniform. Zinc powder is slowly poured in, the disperser speed is adjusted and dispersed for a certain time, and then filtered to obtain resin-free zinc paste. S104, a solvent-resistant zinc coating that does not require sealing is obtained by mixing self-crosslinking resin and resin-free zinc paste in a certain proportion.

[0024] Based on the above technical solution, the resin is one or more of polycarbonate polyol, polyether polyol, polyether ester polyol, trifunctional polyol, and polyfunctional polyol.

[0025] Based on the above technical solution, the first solvent is one or more of xylene, trimethylbenzene, and butyl acetate.

[0026] Based on the above technical solution, the catalyst is one or more of ferric chloride, zinc naphthenate, and organic bismuth.

[0027] Based on the above technical solution, the curing agent is one or more of carbodiimide-urea ketimide modified 4,4'-diphenylmethane diisocyanate and polymethyl polyphenyl isocyanate.

[0028] Based on the above technical solution, the second solvent is one or more of xylene, trimethylbenzene, methyl acetal, solvent oil, ethyl acetate, and butyl acetate.

[0029] Based on the above technical solution, the additive is an anti-settling additive or a rheology modifier. The anti-settling additive is one or more of organic bentonite, fumed silica, polyamide wax, and ultrafine silica. The rheology modifier is one or more of modified polyamide wax paste, modified urea solution rheology modifier, and polyurea anti-settling agent.

[0030] Based on the above technical solution, the dispersant is one or more of polyether, polyurethane, and polyester dispersants.

[0031] Based on the above technical solution, the mixing ratio of self-crosslinking resin and resin-free zinc paste is (7~9):1.

[0032] Secondly, the present invention provides a solvent-resistant zinc spraying coating that does not require sealing, which is prepared according to the preparation method of the solvent-resistant zinc spraying coating described in any of the above embodiments.

[0033] Thirdly, the present invention provides the application of the solvent-resistant zinc spraying coating prepared by the method of preparing the solvent-resistant zinc spraying coating according to any one of the above embodiments in civil engineering and building engineering.

[0034] Example 1 Polycarbonate diol, BASF trifunctional polyol, and xylene (mass ratio 3:7:60) were added sequentially to the reactor. While stirring, the mixture was heated to 150°C for dehydration. The mixture was observed in the water separator until no water was removed, and then cooled to room temperature. Organic bismuth, carbodiimide-urea ketimide-modified 4,4'-diphenylmethane diisocyanate, and polymethylene polyphenyl isocyanate (mass ratio 0.05:10:10) were added sequentially to the reactor. While stirring, the mixture was heated to 80°C and held at that temperature for 2 hours, then heated to 100°C and held at that temperature for 2 hours. The process should be terminated and cooled to room temperature, then filtered to obtain a self-crosslinking resin. Xylene, organobentonite, and a polyether dispersant (mass ratio 13:1:0.5) are poured into a disperser and dispersed for 10 minutes at a speed of 800 rpm. Zinc powder (zinc powder to xylene mass ratio 82:10) is slowly poured in, and the disperser speed is adjusted to 1500 rpm. The mixture is dispersed for 30 minutes, filtered, and a resin-free zinc paste is obtained. The self-crosslinking resin and the resin-free zinc paste are mixed at a mass ratio of 9:1 to obtain a solvent-resistant, non-sealing zinc coating.

[0035] Example 2 The synthesis method in this embodiment is the same as that in Example 1, and the same parts are omitted. The difference from Example 1 is that the mass ratio of self-crosslinking resin to resin-free zinc paste is 8:1.

[0036] Example 3 The synthesis method in this embodiment is the same as that in Example 1, and the same parts are omitted. The difference from Example 1 is that the mass ratio of self-crosslinking resin to resin-free zinc paste is 7:1.

[0037] Example 4 The synthesis method in this embodiment is the same as that in Example 1, with the same parts omitted. The difference from Example 1 is that the organic bentonite is replaced with a modified urea solution rheology modifier, and the mass ratio of self-crosslinking resin to resin-free zinc paste is 9:1.

[0038] Example 5 The synthesis method in this embodiment is the same as that in Example 1, with the same parts omitted. The difference from Example 1 is that the organic bentonite is replaced with a modified urea solution rheology modifier, and the mass ratio of self-crosslinking resin to resin-free zinc paste is 8:1.

[0039] Example 6 The synthesis method in this embodiment is the same as that in Example 1, with the same parts omitted. The difference from Example 1 is that the organic bentonite is replaced with a modified urea solution rheology modifier, and the mass ratio of self-crosslinking resin to resin-free zinc paste is 7:1.

[0040] Comparative Example 1 Add 200g of acrylic modified resin and disperse at 600 rpm for 10 minutes. Slowly add zinc powder (in a mass ratio of 9:1 to acrylic modified resin), adjust the speed to 1200 rpm, and maintain stirring for 30 minutes to disperse evenly. Filter and package to obtain cold-coated zinc coating.

[0041] Comparative Example 2 Add 200g of epoxy modified resin and disperse at 600 rpm for 15 minutes. Slowly add zinc powder (with a mass ratio of 9:1 to epoxy modified resin), adjust the speed to over 1500 rpm, and maintain stirring for 30 minutes to disperse evenly. Add propylene glycol methyl ether and ethylene glycol methyl ether to adjust the viscosity, filter and package to obtain cold-coated zinc coating.

[0042] The coatings prepared in Examples 1-6 and Comparative Examples 1-2 were subjected to performance tests according to the methods specified in relevant national standards, and the results are shown in Table 1.

[0043] Table 1 Performance test results of the coatings prepared in Examples 1-6 and Comparative Examples 1-2

[0044] The coatings prepared in Examples 1-6 and Comparative Examples 1-2 were sprayed onto standard samples. The density of the coating film was observed using a 400x microscope. The coating film of Examples 1-6 had a smooth surface with small and uniform voids. The coating film of Comparative Example 1 had a smooth surface with large and uneven voids. The coating film of Comparative Example 2 had a smooth surface with large and uniform voids.

[0045] The coatings prepared in Examples 1-6 and Comparative Examples 1-2 were subjected to compatibility tests. The coatings from Examples 1-6 and Comparative Examples 1-2 were used to prepare coatings, and the test products were subjected to compatibility tests and interlayer adhesion tests with epoxy micaceous iron oxide intermediate paint without a sealing coat. The substrate size was 150mm*70mm*5mm, the sandblasted steel plate had a cleanliness of sa2.5, a roughness of 40μm~50μm, and a film thickness of 80μm~100μm. After curing at room temperature for 8 hours, the coatings were directly sprayed onto commonly available brands of epoxy micaceous iron oxide intermediate paint. The results are shown in Table 2.

[0046] Table 2. Compatibility test results of the coatings prepared in Examples 1-6 and Comparative Examples 1-2

[0047] The present invention has been described above by way of example, but the present invention is not limited to the specific embodiments described above. Any modifications or variations made based on the present invention shall fall within the scope of protection claimed by the present invention.

Claims

1. A method for preparing a solvent-resistant zinc spray coating that does not require sealing, characterized in that, Includes the following steps: The resin and the first solvent were added to the reaction vessel in sequence, and the mixture was heated while stirring to dehydrate. The water separator was observed until no water was removed from the water separator, and then cooled to room temperature. The resin is a polycarbonate polyol and a trifunctional polyol. A catalyst and a curing agent were added sequentially to a reaction vessel. While stirring, the temperature was raised to 80 degrees Celsius and held for a certain period of time. Then, the temperature was raised to 100 degrees Celsius and held for a certain period of time. The reaction was terminated and cooled to room temperature. The mixture was then filtered to obtain a self-crosslinking resin. The catalyst was one or more of ferric chloride, zinc naphthenate, and organic bismuth. The curing agent was carbodiimide-urea ketimide modified 4,4'-diphenylmethane diisocyanate and polymethyl polyphenyl isocyanate. The second solvent, additives and dispersant are poured into a disperser and dispersed. The disperser is rotated at a preset speed until the mixture is uniform. Zinc powder is slowly poured in, the speed of the disperser is adjusted and the reaction is carried out for a certain period of time. After filtration, resin-free zinc paste is obtained. A solvent-resistant zinc coating that does not require sealing is obtained by mixing self-crosslinking resin and resin-free zinc paste in a certain proportion.

2. The method for preparing the solvent-resistant zinc spray coating without sealing according to claim 1, characterized in that, The first solvent is one or more of xylene, trimethylbenzene, and butyl acetate.

3. The method for preparing the solvent-resistant zinc spray coating without sealing according to claim 1, characterized in that, The second solvent is one or more of xylene, trimethylbenzene, methyl acetal, solvent oil, ethyl acetate, and butyl acetate.

4. The method for preparing the solvent-resistant zinc spray coating without sealing according to claim 1, characterized in that, The additive is an anti-settling additive or a rheology modifier. The anti-settling additive is one or more of organic bentonite, fumed silica, polyamide wax, and ultrafine silica. The rheology modifier is one or more of modified polyamide wax paste, modified urea solution rheology modifier, and polyurea anti-settling agent.

5. The method for preparing the solvent-resistant zinc spray coating without sealing according to claim 1, characterized in that, The mixing ratio of self-crosslinking resin and resin-free zinc paste is (7~9):

1.

6. A solvent-resistant zinc spray coating that does not require sealing, characterized in that, The zinc spraying coating that is free from sealing and resistant to solvent spraying is prepared according to any one of claims 1 to 5.

7. The application of the solvent-resistant zinc spraying coating prepared by the method of any one of claims 1 to 5 in civil engineering.

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