Sealing-free solvent-resistant zinc spraying coating as well as preparation method and application thereof

Abstract

The invention relates to the technical field of coating chemistry, and provides a preparation method of a sealing-free solvent-resistant zinc spraying coating, which comprises the following steps: sequentially adding resin and a first solvent into a reaction kettle, heating while stirring to dehydrate, observing a water segregator until no water is removed from the water segregator, and cooling to room temperature; sequentially adding a catalyst and a curing agent into the reaction kettle, heating to a first temperature while stirring, preserving heat for a certain time, heating to a second temperature, preserving heat for a certain time, ending the reaction, cooling to room temperature, and filtering to obtain self-crosslinking resin; pouring a second solvent, an auxiliary agent and a dispersing agent into a dispersing machine for dispersing, rotating the dispersing machine at a preset rotating speed until the materials are uniformly mixed, slowly pouring zinc powder, adjusting the rotating speed of the dispersing machine, reacting for a certain time, and filtering to obtain resin-free zinc slurry; and mixing the self-crosslinking resin and the resin-free zinc slurry according to a certain proportion to obtain the sealing-free solvent-resistant zinc spraying coating. The invention further discloses the sealing-free solvent-resistant zinc spraying coating and application thereof.

Description

Technical Field

[0001] The invention belongs to the technical field of coating chemistry, and in particular relates to a sealing-free solvent-resistant zinc spray coating and a preparation method and application thereof. Background Art

[0002] At present, cold zinc coating is a single-component coating, which is mainly composed of three parts: high-purity zinc powder, co-solvent and special organic mixed resin. The zinc content in the dry film of the coating is higher than 96%, and it has the dual advantages of hot-dip galvanizing and zinc-rich coating. Cold zinc coating can achieve the effect of hot-dip galvanizing and hot-spraying zinc by construction and curing at room temperature, providing long-term cathodic protection and physical shielding dual protection functions. Cold zinc coating has excellent anti-corrosion performance and convenient construction. In recent years, cold zinc coating has been increasingly adopted by design institutes as a new type of anti-corrosion coating in the bridge industry and petrochemical industry, and is used in steel structure bridges, ships, petrochemicals and other industries. Cold zinc coating is simpler, more convenient, more environmentally friendly and low-energy than hot-spraying zinc and hot-dip galvanizing in construction.

[0003] During the construction process, the staff found that cold zinc coating has relatively high construction requirements, and there are problems in construction and matching to varying degrees. It is difficult to make a single coat of 80μm without sagging. The film-forming material of single-component cold zinc coating is mostly thermoplastic resin, and the solvent resistance is very poor. If no sealing paint is applied on the cold zinc coating, and the two-component epoxy micaceous iron intermediate paint and epoxy thick paste intermediate paint are directly sprayed, serious construction quality accidents such as coating biting, shedding, and extremely reduced adhesion will occur. The traditional solution is to spray a thin layer of two-component sealing paint on the cold zinc coating. This method is not easy to control the film thickness and has leakage and overspraying phenomena, which has certain construction quality risks. For the Yin-Yang corners of steel structures and complex structural workpieces, there will be a phenomenon of loose sealing, which will lead to quality accidents such as biting. The thin spray sealing construction process requires changing the dilution ratio and adding more organic solvents, which increases the volatilization of organic solvents. The thin spray sealing construction process causes environmental pollution, endangers the health of construction workers, and increases material costs, labor costs, and prolongs the construction period.

[0004] In order to solve the above technical problems, the present invention designs a sealing-free solvent-resistant zinc spray coating and a preparation method and application thereof. Summary of the invention

[0005] The present invention provides a sealing-free solvent-resistant zinc spray coating and a preparation method and application thereof, aiming to solve the problems of biting and falling off between coating systems during cold zinc coating construction; poor solvent resistance of the coating, dissolution, and a sharp drop in adhesion; and to solve the problem of incompatibility with various intermediate coatings caused by not applying sealing paint during cold zinc coating construction and the problem of 70-90μm sag of a single coating.

[0006] To achieve the above-mentioned purpose, the present invention provides the following technical scheme: a method for preparing a non-blocking solvent-resistant zinc spray coating, comprising the following steps: adding a resin and a first solvent to a reactor in sequence, heating up while stirring for dehydration, observing a water separator until no water is removed from the water separator, and cooling to room temperature; adding a catalyst and a curing agent to the reactor in sequence, heating up to a first temperature while stirring and keeping the temperature for a certain time, then heating up to a second temperature and keeping the temperature for a certain time, terminating the reaction and cooling to room temperature, filtering, and obtaining a self-crosslinking resin; pouring a second solvent, an auxiliary agent, and a dispersant into a disperser for dispersion, rotating the disperser at a preset speed until the mixture is evenly mixed, slowly pouring in zinc powder, adjusting the speed of the disperser to react for a certain time, filtering, and obtaining a resin-free zinc slurry; mixing the self-crosslinking resin and the resin-free zinc slurry in a certain proportion to obtain a non-blocking solvent-resistant zinc spray coating.

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

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

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

[0010] On the basis of the above technical solution, the curing agent is one or more of carbodiimide-uretonimine 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, trimethylol, methylal, solvent oil, ethyl acetate, and butyl acetate.

[0012] Based on the above technical solution, the auxiliary agent is an anti-settling auxiliary agent or a rheological auxiliary agent, the anti-settling auxiliary agent is one or more of organic bentonite, fumed silica, polyamide wax, and ultrafine silica, and the rheological auxiliary agent is one or more of modified polyamide wax paste, modified urea solution rheological agent, 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 the self-crosslinking resin and the resin-free zinc paste is (7~9):1.

[0015] In a second aspect, the present invention provides a non-blocking solvent-resistant zinc spray coating, which is prepared according to the preparation method of the non-blocking solvent-resistant zinc spray coating described in any one of the above embodiments.

[0016] In a third aspect, the present invention provides the use of a non-sealed solvent-resistant zinc spray coating prepared by the method for preparing a non-sealed solvent-resistant zinc spray coating according to any one of the above embodiments in civil engineering and construction engineering.

[0017] Compared with the related art, the beneficial effects of the present invention are as follows: The present invention first prepares a self-crosslinking resin, which is a high molecular polymer material. In the process of film formation or curing, no special auxiliary agents such as coupling agents and curing agents need to be added. It can undergo a crosslinking curing reaction with oxygen moisture in the air at room temperature. After curing, the polymer chains can crosslink into a three-dimensional network structure by themselves. The self-crosslinking resin itself has excellent resistance to neutral salt spray and xylene solvents. The characteristics of this self-crosslinking resin make the prepared non-sealed solvent-resistant zinc spray coating have higher chemical corrosion resistance and excellent solvent resistance, and have good matching compatibility with various epoxy intermediate paints sold on the market. In addition, the excellent flexibility makes the paint film not crack or fall off after drying and curing, and has excellent adhesion to the substrate. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the prior art descriptions are briefly introduced below. Obviously, the drawings described below are only one embodiment of the present invention, and for ordinary technicians in this field, other implementation drawings can be derived from the provided drawings without creative work.

[0019] Figure 1 The present invention provides a flow chart of a method for preparing a sealing-free solvent-resistant zinc spray coating. DETAILED DESCRIPTION

[0020] The following will combine the contents in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work 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 those commonly understood by those skilled in the art of the present invention. The terms used in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used in this specification includes any and all combinations of one or more of the related listed items.

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

[0023] Combination Figure 1 As shown, the present invention provides a method for preparing a sealing-free solvent-resistant zinc spray coating, comprising the following steps: S101, adding the resin and the first solvent into the reaction kettle in sequence, heating the reactor while stirring to dehydrate, observing the water separator until no water is removed from the water separator, and cooling the reactor to room temperature; S102, adding a catalyst and a curing agent to a reaction kettle in sequence, heating the reaction kettle to a first temperature and keeping the temperature for a certain time while stirring, then heating the reaction kettle to a second temperature and keeping the temperature for a certain time, terminating the reaction, cooling the reaction kettle to room temperature, filtering the reaction kettle, and obtaining a self-crosslinking resin; S103, pouring the second solvent, the auxiliary agent and the dispersant into a disperser for dispersion, rotating the disperser at a preset speed until the mixture is uniform, slowly pouring the zinc powder, adjusting the speed of the disperser for dispersion for a certain time, filtering, and obtaining a resin-free zinc slurry; S104, mixing the self-crosslinking resin and the resin-free zinc paste in a certain proportion to obtain a sealing-free solvent-resistant zinc spray coating.

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

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

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

[0027] On the basis of the above technical solution, the curing agent is one or more of carbodiimide-uretonimine 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, trimethylol, methylal, solvent oil, ethyl acetate, and butyl acetate.

[0029] Based on the above technical solution, the auxiliary agent is an anti-settling auxiliary agent or a rheological auxiliary agent, the anti-settling auxiliary agent is one or more of organic bentonite, fumed silica, polyamide wax, and ultrafine silica, and the rheological auxiliary agent is one or more of modified polyamide wax paste, modified urea solution rheological agent, 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 the self-crosslinking resin and the resin-free zinc paste is (7~9):1.

[0032] In a second aspect, the present invention provides a non-blocking solvent-resistant zinc spray coating, which is prepared according to the preparation method of the non-blocking solvent-resistant zinc spray coating described in any one of the above embodiments.

[0033] In a third aspect, the present invention provides the use of a non-sealed solvent-resistant zinc spray coating prepared by the method for preparing a non-sealed solvent-resistant zinc spray coating according to any one of the above embodiments in civil engineering and construction engineering.

[0034] Example 1 Polycarbonate diol, BASF trifunctional polyol and xylene (mass ratio of 3:7:60) were added to the reactor in sequence, and the temperature was raised to 150 degrees for dehydration while stirring, and the water separator was observed until no water was removed from the water separator, and then cooled to room temperature; organic bismuth, carbodiimide-uretonimine modified 4,4'-diphenylmethane diisocyanate and polymethyl polyphenyl isocyanate (mass ratio of 0.05:10:10) were added to the reactor in sequence, and the temperature was raised to 80 degrees for 2 hours while stirring, and then raised to 100 degrees for 2 hours. The process should be terminated and cooled to room temperature, filtered to obtain a self-crosslinking resin; xylene, organic bentonite and polyether dispersant (mass ratio of 13:1:0.5) are poured into a disperser and dispersed for 10 minutes. The disperser rotates at a speed of 800 revolutions per minute, and zinc powder is slowly poured in (the mass ratio of zinc powder to xylene is 82:10). The speed of the disperser is adjusted to 1500 revolutions per minute, dispersed for 30 minutes, filtered to obtain a resin-free zinc slurry; the self-crosslinking resin and the resin-free zinc slurry are mixed in a mass ratio of 9:1 to obtain a non-sealed solvent-resistant zinc spray coating.

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

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

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

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

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

[0040] Comparative Example 1 Add 200 grams of acrylic modified resin and disperse it at a speed of 600 revolutions per minute for 10 minutes, slowly add zinc powder (the mass ratio of zinc powder to acrylic modified resin is 9:1), adjust the speed to 1200 revolutions per minute, maintain stirring time for 30 minutes, disperse evenly, filter and package to obtain cold-coated zinc coating.

[0041] Comparative Example 2 Add 200 grams of epoxy modified resin and disperse it at a speed of 600 revolutions per minute for 15 minutes, slowly add zinc powder (the mass ratio of zinc powder to epoxy modified resin is 9:1), adjust the speed to more than 1500 revolutions per minute, maintain stirring time for 30 minutes, disperse evenly, add propylene glycol methyl ether and ethylene glycol methyl ether to adjust 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. 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 on standard samples, and the density of the paint films was observed using a 400x microscope. The paint films of Examples 1-6 had smooth surfaces, small and evenly distributed voids, the paint films of Comparative Example 1 had smooth surfaces, large and unevenly distributed voids, and the paint films of Comparative Example 2 had smooth surfaces, large and evenly distributed voids.

[0045] The coatings prepared in Examples 1-6 and Comparative Examples 1-2 were tested for compatibility. The coatings obtained in Examples 1-6 and Comparative Examples 1-2 were prepared into coatings. The test products were tested for compatibility and interlayer adhesion with epoxy micaceous iron intermediate paint without sealing paint. 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, it was directly sprayed on a common brand of epoxy micaceous iron intermediate paint on the market. 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 is described above by way of examples, but the present invention is not limited to the above specific embodiments, and any changes or modifications made based on the present invention belong to the scope of protection claimed by the present invention.

Claims

1. A method for preparing a non-sealed solvent-resistant zinc spray coating, characterized in that: The following steps are involved: The resin and the first solvent are sequentially added to the reaction kettle, and the temperature is raised while stirring to dehydrate, and the water separator is observed until no water is removed from the water separator, and then cooled to room temperature; Adding a catalyst and a curing agent to the reaction kettle in sequence, heating to a first temperature and keeping the temperature for a certain time while stirring, then heating to a second temperature and keeping the temperature for a certain time, terminating the reaction and cooling to room temperature, filtering, and obtaining a self-crosslinking resin; Pour the second solvent, the auxiliary agent and the dispersant into a disperser for dispersion, rotate the disperser at a preset speed until the mixture is uniform, slowly pour in the zinc powder, adjust the speed of the disperser for a certain reaction time, filter, and obtain a resin-free zinc slurry; The self-crosslinking resin and the resin-free zinc paste are mixed in a certain proportion to obtain a sealing-free solvent-resistant zinc spray coating.

2. The method for preparing the non-sealed solvent-resistant zinc spray coating according to claim 1, characterized in that: The resin is one or more of polycarbonate polyol, polyether polyol, polyether ester polyol, trifunctional polyol and multifunctional polyol.

3. The method for preparing the non-sealed solvent-resistant zinc spray coating according to claim 1, characterized in that: The first solvent is one or more of xylene, trimethylbenzene, and butyl acetate.

4. The method for preparing the non-sealed solvent-resistant zinc spray coating according to claim 1, characterized in that: The catalyst is one or more of ferric chloride, zinc naphthenate, and organic bismuth.

5. The method for preparing the non-sealed solvent-resistant zinc spray coating according to claim 1, characterized in that: The curing agent is one or more of carbodiimide-uretonimine modified 4,4'-diphenylmethane diisocyanate and polymethyl polyphenyl isocyanate.

6. The method for preparing the non-sealed solvent-resistant zinc spray coating according to claim 1, characterized in that: The second solvent is one or more of xylene, trimethylbenzene, methylal, solvent oil, ethyl acetate, and butyl acetate.

7. The method for preparing the non-sealed solvent-resistant zinc spray coating according to claim 1, characterized in that: The additive is an anti-settling additive or a rheological additive. The anti-settling additive is one or more of organic bentonite, fumed silica, polyamide wax, and ultrafine silica. The rheological additive is one or more of modified polyamide wax paste, modified urea solution rheological agent, and polyurea anti-settling agent.

8. The method for preparing the non-sealed solvent-resistant zinc spray coating according to claim 1, characterized in that: The mixing ratio of self-crosslinking resin and resin-free zinc paste is (7~9):

1.

9. A non-sealed solvent-resistant zinc spray coating, characterized in that: The method for preparing the non-sealed solvent-resistant zinc spray coating according to any one of claims 1 to 8 is disclosed.

10. Use of the non-sealed solvent-resistant zinc spray coating prepared by the method for preparing the non-sealed solvent-resistant zinc spray coating according to any one of claims 1 to 8 in civil engineering and construction engineering.

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