Polysiloxane anticorrosive paint as well as preparation method and application thereof

Abstract

The invention discloses a polysiloxane anticorrosive coating as well as a preparation method and application thereof. The polysiloxane anticorrosive paint comprises a component A and a component B, the component A and the component B are matched according to the mass ratio of (6-16): 1 during use, the component A comprises epoxy-terminated polysiloxane, polyether epoxy co-modified silicone oil, pigment, filler, a dispersing agent, a defoaming agent, a rheological additive and a solvent, and the component B comprises amino silane and a curing accelerator. The polysiloxane anticorrosive paint can be cured at normal temperature, a formed paint film is large in crosslinking density, good in flexibility, good in corrosion resistance, outstanding in weather resistance and good in shielding property, the polysiloxane anticorrosive paint can be used for metal corrosion prevention in a special corrosive environment, the preparation method is simple, and the polysiloxane anticorrosive paint is suitable for large-scale industrial production and application.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of heavy-duty anticorrosion technology, and particularly relates to a polysiloxane anticorrosive coating, a preparation method and application thereof. BACKGROUND

[0002] Heavy-duty anticorrosive coating refers to a special coating capable of providing long-term effective protection (usually designed for a service life of more than 10 years, or even 20-30 years) in a severe corrosive environment (for example, marine environment, chemical corrosive environment, etc.). Compared with ordinary anticorrosive coating, heavy-duty anticorrosive coating has higher anticorrosive performance, longer service life and more stringent construction requirements.

[0003] Epoxy-terminated polysiloxane has weather resistance of polysiloxane, high reactivity and adhesion of epoxy resin, and is an ideal film-forming resin for heavy-duty anticorrosive coating. However, the existing film-forming resin for polysiloxane coating has insufficient flexibility and relatively large brittleness, and the paint film is prone to cracking and peeling under cold and hot environments or mechanical impact. In addition, the pigment system and filler system in the existing polysiloxane coating also have problems of insufficient durability and unsatisfactory shielding performance in harsh outdoor environments. In summary, the existing polysiloxane coating cannot completely meet the requirements of practical applications, and the practical application is greatly limited.

[0004] Therefore, it is of great significance to develop a polysiloxane anticorrosive coating with good flexibility, good weather resistance, good shielding performance and excellent anticorrosive performance. SUMMARY

[0005] The present application aims to provide a polysiloxane anticorrosive coating, a preparation method and application thereof.

[0006] The technical solution adopted by the present application is as follows: A polysiloxane anticorrosive coating comprises A component and B component, and the A component and the B component are matched in a mass ratio of 6-16:1 when used. The A component comprises the following components in mass percentage: Epoxy-terminated polysiloxane: 40%-65%; Polyether epoxy co-modified silicone oil: 3%-10%; Pigment: 4%-25%; Filler: 6%-30%; Dispersing agent: 0.3%-0.8%; Defoaming agent: 0.2%-0.4%; Rheological aid: 0.5%-1.5%; Solvent: 4%-9%; The B component comprises the following components in mass percentage: Aminosilanes: 99.4%–99.7%; Curing accelerator: 0.3%~0.6%.

[0007] Preferably, the epoxy equivalent of the terminal epoxy polysiloxane is 780 g / eq to 840 g / eq.

[0008] More preferably, the epoxy-terminated polysiloxane is EP-S19L from Wuhan Niobium Energy Materials Co., Ltd.

[0009] Preferably, the epoxy equivalent of the polyether epoxy co-modified silicone oil is 8500 g / eq to 12000 g / eq.

[0010] More preferably, the polyether epoxy co-modified silicone oil is Dow Corning's DOWSIL. TM SF 8421 EG Fluid.

[0011] Preferably, the pigment is a coated modified rutile titanium dioxide, and the coating is at least one of aluminum, zirconium, and organosilicon.

[0012] More preferably, the pigment is KRONOS 2310 from KRONOS GmbH, Germany, or KRONOS from KRONOS GmbH, Germany. ® 2360, at least one of Chemours' R-960.

[0013] Preferably, the filler is one of sericite powder, talc powder, sericite powder-talc powder composite, sericite powder-barium sulfate powder composite, talc powder-barium sulfate powder composite, and sericite powder-talc powder-barium sulfate powder composite.

[0014] Preferably, the particle size of the filler is 15μm to 25μm.

[0015] Preferably, the dispersant is at least one of BYK-163, BYK-164, Disponer 903, and Disponer 904S.

[0016] Preferably, the defoamer is at least one of Deqian Defom 5300, Deqian Defom 5400, and Deqian Defom 6500.

[0017] Preferably, the rheology modifier is at least one of organobentonite, polyamide wax, and fumed silica.

[0018] Preferably, the solvent is at least one of xylene, n-butanol, and propylene glycol methyl ether acetate.

[0019] Preferably, the aminosilane is at least one of γ-aminopropyltriethoxysilane (silane coupling agent KH-550), γ-aminoethylaminopropyltrimethoxysilane (silane coupling agent KH-792), and bis[3-(trimethoxysilyl)propyl]amine.

[0020] More preferably, the aminosilane is Dynasylan from Evonik Industries, Germany. ® AMEO (main component is γ-aminopropyltriethoxysilane), Evonik's Dynasylan ® 1124 (the main component is at least one of bis[3-(trimethoxysilyl)propyl]amine).

[0021] Preferably, the curing accelerator is an organotin catalyst.

[0022] Preferably, the organotin catalyst is at least one of dibutyltin dilaurate and di-n-octyltin dilaurate.

[0023] A method for preparing a polysiloxane anticorrosive coating as described above includes the following steps: Preparation of component A: Add terminal epoxy polysiloxane and solvent to a dispersion device and stir evenly. Then add polyether epoxy co-modified silicone oil, dispersant, rheology modifier and defoamer in sequence and stir evenly. Then add pigment and filler and stir evenly. Then grind and filter to obtain component A. Preparation of component B: The aminosilane and curing accelerator were stirred evenly and filtered to obtain component B.

[0024] Preferably, a method for preparing a polysiloxane anticorrosive coating as described above includes the following steps: Preparation of Component A: Add terminal epoxy polysiloxane and solvent to a dispersion device, and stir for 5 min to 10 min at a stirring speed of 200 rpm to 400 rpm. Then add polyether epoxy co-modified silicone oil, dispersant, rheology modifier and defoamer in sequence and continue stirring for 10 min to 20 min. Then add pigment and filler and adjust the stirring speed to 800 rpm to 1500 rpm and stir for 20 min to 30 min. Then grind until the particle size is ≤30 μm, filter and obtain Component A. Preparation of component B: Add aminosilane and curing accelerator to a dispersion device, stir for 20 min to 30 min at a stirring rate of 150 rpm to 300 rpm, filter, and obtain component B.

[0025] A method for using the polysiloxane anticorrosive coating as described above: Mix component A and component B in a certain proportion until homogeneous, then let stand for 10 to 20 minutes to allow to mature before applying.

[0026] A polysiloxane anticorrosion coating as described above is used for corrosion protection of storage tanks in the petrochemical industry or for corrosion protection of steel structures in marine engineering.

[0027] The beneficial effects of this invention are: the polysiloxane anticorrosion coating of this invention can be cured at room temperature, and the resulting paint film has high cross-linking density, good flexibility, good corrosion resistance, outstanding weather resistance, and good shielding properties. It can be used for metal corrosion protection in special corrosive environments (e.g., corrosion protection of storage tanks in the petrochemical industry, corrosion protection of steel structures in marine engineering, etc.). Moreover, its preparation method is simple and suitable for large-scale industrial production and application.

[0028] Specifically: 1) Excellent balance of rigidity and toughness and impact resistance: The polysiloxane anticorrosive coating of the present invention contains polyether epoxy co-modified silicone oil, which can introduce flexible segments, significantly reduce the internal stress of the paint film, and improve the flexibility and impact resistance of the paint film. The bending test result of the paint film is ≤2mm and the impact resistance is ≥50kg·cm. It overcomes the problems of insufficient flexibility and excessive brittleness of the paint film formed by the existing polysiloxane coating with end-epoxy polysiloxane as the film-forming resin. 2) Optimized curing system and performance: The polysiloxane anticorrosive coating of the present invention contains aminosilane, the amino group of which can undergo efficient ring-opening crosslinking with the epoxy group of the terminal epoxy polysiloxane, and the alkoxy group of which can undergo hydrolysis and condensation with the silanol group in the system to form a dense and stable organic-inorganic hybrid network, which can impart excellent flexibility and high adhesion to the coating film while ensuring high reactivity. 3) Excellent weather resistance and gloss and color retention: The polysiloxane anticorrosive coating of the present invention contains coated modified rutile titanium dioxide, which has excellent light resistance and anti-chalking properties. Combined with the assistance of fillers, it can give the paint film excellent resistance to artificial weathering (≥3000h). 4) Enhanced physical shielding effect and anti-permeability performance: The polysiloxane anti-corrosion coating of the present invention contains flake fillers (sericite powder, talc powder), which can form a "maze effect" by arranging them in parallel in the paint film, which greatly extends the penetration path of corrosive media such as water, oxygen, and chloride ions. The salt spray resistance of the paint film can reach 3000h without abnormality. 5) System compatibility and construction friendliness: The polysiloxane anticorrosion coating of the present invention can be cured at room temperature, has a moderate service life, can be sprayed or brushed, and has good compatibility with common epoxy zinc-rich primers and epoxy micaceous iron oxide intermediate paints, making it suitable for harsh outdoor environments such as petrochemical, marine, and bridge industries. 6) Compared with traditional epoxy coatings, the polysiloxane anticorrosive coating of the present invention has significantly better weather resistance, damp heat resistance, UV aging resistance and long-term anticorrosive performance of the coating film formed, especially in harsh environments with high temperature, high humidity and strong ultraviolet radiation, it has greater service advantages. Detailed Implementation

[0029] The present invention will be further explained and described below with reference to specific embodiments.

[0030] Example 1: A polysiloxane anticorrosive coating, the composition of which is shown in the table below: Table 1. Composition of a polysiloxane anticorrosive coating

[0031] The preparation method of the above-mentioned polysiloxane anticorrosive coating is as follows: Preparation of Component A: EP-S19L, xylene, and propylene glycol methyl ether acetate were added to dispersion tank A and stirred for 5 minutes at a stirring speed of 300 rpm. Then, DOWSIL was added sequentially. TM After adding SF 8421 EG Fluid, BYK-163, polyamide wax and Deqian Defom 5400, continue stirring for 10 min. Then add KRONOS 2310 and sericite powder and stir at 1000 rpm for 20 min. Then transfer to a sand mill and grind until the particle size is ≤30μm. Filter to obtain component A. Preparation of component B: Dynasylan ® AMEO, Dynasylan ® 1124 and dibutyltin dilaurate were added to dispersion tank B, and then stirred for 20 minutes at a stirring speed of 200 rpm. After filtration, component B was obtained.

[0032] The application method of the above-mentioned polysiloxane anticorrosive coating is as follows: Mix components A and B at a mass ratio of 6:1 until homogeneous, then let stand for 15 minutes before applying.

[0033] Example 2: A polysiloxane anticorrosive coating, the composition of which is shown in the table below: Table 2. Composition of a polysiloxane anticorrosive coating

[0034] The preparation method of the above-mentioned polysiloxane anticorrosive coating is as follows: Preparation of Component A: EP-S19L, xylene, and propylene glycol methyl ether acetate were added to dispersion tank A and stirred for 5 minutes at a stirring speed of 300 rpm. Then, DOWSIL was added sequentially. TMAfter adding SF 8421 EG Fluid, Disponer 904S, polyamide wax and Deqian Defom 6500, continue stirring for 10 min. Then add KRONOS 2310, sericite powder and precipitated barium sulfate, and stir at 1000 rpm for 20 min. Then transfer to a sand mill and grind until the particle size is ≤30μm. Filter to obtain component A. Preparation of component B: Dynasylan ® AMEO and dibutyltin dilaurate were added to dispersion tank B and stirred for 20 minutes at a stirring speed of 200 rpm. After filtration, component B was obtained.

[0035] The application method of the above-mentioned polysiloxane anticorrosive coating is as follows: Mix components A and B at a mass ratio of 16:1 until homogeneous, then let stand for 15 minutes before applying.

[0036] Example 3: A polysiloxane anticorrosive coating, the composition of which is shown in the table below: Table 3. Composition of a polysiloxane anticorrosive coating

[0037] The preparation method of the above-mentioned polysiloxane anticorrosive coating is as follows: Preparation of Component A: EP-S19L, xylene, and propylene glycol methyl ether acetate were added to dispersion tank A and stirred for 5 minutes at a stirring speed of 300 rpm. Then, DOWSIL was added sequentially. TM After adding SF 8421 EG Fluid, BYK-164, polyamide wax and Deqian Defom 5300, continue stirring for 10 min. Then add KRONOS 2310, sericite powder and precipitated barium sulfate, and stir at 1000 rpm for 20 min. Then transfer to a sand mill and grind until the particle size is ≤30μm. Filter to obtain component A. Preparation of component B: Dynasylan ® AMEO, Dynasylan ® 1124 and dibutyltin dilaurate were added to dispersion tank B, and then stirred for 20 minutes at a stirring speed of 200 rpm. After filtration, component B was obtained.

[0038] The application method of the above-mentioned polysiloxane anticorrosive coating is as follows: Mix components A and B at a mass ratio of 7.2:1 until homogeneous, then let stand for 15 minutes before applying.

[0039] Comparative Example 1: (Polyether epoxy co-modified silicone oil without toughening resin) A type of anti-corrosion coating, in addition to removing DOWSIL from component A TM Except for replacing SF 8421 EG Fluid with EP-S19L (i.e., adjusting the mass percentage of EP-S19L to 61%), the polysiloxane anti-corrosion coating of Example 1 is completely identical.

[0040] Comparative Example 2: (excluding sheet filler) An anti-corrosion coating is identical to the polysiloxane anti-corrosion coating of Example 1, except that the sericite powder and other components in component A are replaced by precipitated barium sulfate.

[0041] Comparative Example 3: (The pigment is anatase titanium dioxide) An anti-corrosion coating is identical to the polysiloxane anti-corrosion coating of Example 1, except that the mass of KRONOS 2310 in component A is replaced with anatase titanium dioxide.

[0042] Comparative Example 4: (The film-forming resin is hydrogenated bisphenol A epoxy resin) An anti-corrosion coating is identical to the polysiloxane anti-corrosion coating of Example 1, except that the EP-S19L in component A is replaced by hydrogenated bisphenol A epoxy resin WZST-3000 (epoxy equivalent of 215 g / eq to 240 g / eq) and components A and B are compounded in a 1:1 ratio according to the epoxy equivalent of component A and the amine equivalent of component B when the anti-corrosion coating is used.

[0043] Performance testing: The polysiloxane anti-corrosion coatings of Examples 1-3 and the anti-corrosion coatings of Comparative Examples 1-4 were applied to the surface of a surface-treated tinplate substrate by spraying with a spray gun to form a film. After curing, the film was tested for hardness, flexibility, adhesion, impact resistance and artificial weathering resistance.

[0044] The polysiloxane anticorrosive coatings of Examples 1-3 and the anticorrosive coatings of Comparative Examples 1-4 were sprayed onto sandblasted Sa2.5 steel plates coated with an epoxy zinc-rich primer with a thickness of 60 μm (dry film) and an epoxy micaceous iron oxide intermediate paint with a thickness of 150 μm (dry film). The paint films (dry film thickness of 80 μm) were completely dried and subjected to neutral salt spray resistance tests.

[0045] The polysiloxane anticorrosive coatings of Examples 1-3 and the anticorrosive coatings of Comparative Examples 1-4 were sprayed onto glass plates. After complete curing at room temperature, the abrasion resistance of the coating film was tested (500g / 500r, CS-10).

[0046] The performance test data of the polysiloxane anticorrosive coatings of Examples 1-3 and the anticorrosive coatings of Comparative Examples 1-4 are shown in the table below: Table 4 Performance test data of polysiloxane anticorrosive coatings in Examples 1-3

[0047] Table 5 Performance test data of anti-corrosion coatings in Comparative Examples 1–4

[0048] As can be seen from Tables 4 and 5: 1) The polysiloxane anticorrosive coating of Example 1 has the best overall performance, especially in terms of the flexibility, impact resistance and long-term weather resistance of the coating film. The polysiloxane anticorrosive coatings of Example 2 and Example 3 achieve different cost and performance positioning while ensuring good performance. 2) Compared with the polysiloxane anticorrosive coating of Example 1, the anticorrosive coating of Comparative Example 1 (without toughening resin polyether epoxy co-modified silicone oil) showed a significant decrease in film flexibility and impact resistance, and the film was brittle and prone to cracking when bent, indicating that DOWSIL TM SF 8421 EG Fluid is crucial for improving the flexibility of the coating film; 3) Compared with the polysiloxane anticorrosive coating of Example 1, the anticorrosive coating of Comparative Example 2 (without flake filler) showed a significant decrease in salt spray resistance and artificial weathering resistance. This is because the physical and ultraviolet shielding effects of the flake filler (sericite powder) were lacking, indicating that the flake filler plays an irreplaceable role in improving the long-term anticorrosive and weather-resistant performance of the coating. 4) Compared with the polysiloxane anticorrosive coating of Example 1, the anticorrosive coating of Comparative Example 3 (pigment is anatase titanium dioxide) showed a significant decrease in the resistance to artificial weathering, indicating that the coating modified rutile titanium dioxide is crucial for improving the weather resistance of the coating film. 5) Compared with the polysiloxane anticorrosive coating of Example 1, the anticorrosive coating of Comparative Example 4 (the film-forming resin is hydrogenated bisphenol A epoxy resin) showed a significant decrease in film hardness, salt spray resistance, artificial aging resistance and wear resistance, indicating that terminal epoxy polysiloxane has a greater long-term protective advantage in harsh environments. In summary, the polysiloxane anticorrosive coating of the present invention forms a film with high cross-linking density, good flexibility, good corrosion resistance, outstanding weather resistance, and good shielding properties. In particular, it combines toughness and ultra-weather resistance, making it suitable for metal corrosion protection in special corrosive environments, and it can provide long-term protection.

[0049] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A polysiloxane anticorrosive coating, characterized in that, It includes component A and component B. When using it, component A and component B should be mixed in a mass ratio of 6 to 16:

1. Component A comprises the following components by mass percentage: Terminally epoxy-based polysiloxanes: 40%–65%; Polyether-epoxy co-modified silicone oil: 3%–10%; Pigment: 4%–25%; Filler: 6%–30%; Dispersant: 0.3%–0.8%; Defoamer: 0.2%–0.4%; Rheology modifiers: 0.5%–1.5%; Solvent: 4%–9%; Component B comprises the following components by mass percentage: Aminosilanes: 99.4%–99.7%; Curing accelerator: 0.3%~0.6%.

2. The polysiloxane anticorrosive coating according to claim 1, characterized in that: The epoxy equivalent of the terminal epoxy polysiloxane is 780 g / eq to 840 g / eq.

3. The polysiloxane anticorrosive coating according to claim 1, characterized in that: The epoxy equivalent of the polyether epoxy co-modified silicone oil is 8500 g / eq to 12000 g / eq.

4. The polysiloxane anticorrosive coating according to any one of claims 1 to 3, characterized in that: The pigment is a coated modified rutile titanium dioxide, and the coating is at least one of aluminum, zirconium, and organosilicon.

5. The polysiloxane anticorrosive coating according to any one of claims 1 to 3, characterized in that: The filler is one of sericite powder, talc powder, sericite powder-talc powder composite, sericite powder-barium sulfate powder composite, talc powder-barium sulfate powder composite, and sericite powder-talc powder-barium sulfate powder composite; the particle size of the filler is 15μm to 25μm.

6. The polysiloxane anticorrosive coating according to any one of claims 1 to 3, characterized in that: The dispersant is at least one of BYK-163, BYK-164, Disponer 903, and Disponer 904S; the defoamer is at least one of Deqian Defom 5300, Deqian Defom 5400, and Deqian Defom 6500; the rheology modifier is at least one of organobentonite, polyamide wax, and fumed silica; and the solvent is at least one of xylene, n-butanol, and propylene glycol methyl ether acetate.

7. The polysiloxane anticorrosive coating according to any one of claims 1 to 3, characterized in that: The aminosilane is at least one of γ-aminopropyltriethoxysilane, γ-aminoethylaminopropyltrimethoxysilane, and bis[3-(trimethoxysilyl)propyl]amine.

8. The polysiloxane anticorrosive coating according to any one of claims 1 to 3, characterized in that: The curing accelerator is an organotin catalyst.

9. A method for preparing a polysiloxane anticorrosive coating as described in any one of claims 1 to 8, characterized in that, Includes the following steps: Preparation of component A: Add terminal epoxy polysiloxane and solvent to a dispersion device and stir evenly. Then add polyether epoxy co-modified silicone oil, dispersant, rheology modifier and defoamer in sequence and stir evenly. Then add pigment and filler and stir evenly. Then grind and filter to obtain component A. Preparation of component B: The aminosilane and curing accelerator were stirred evenly and filtered to obtain component B.

10. The application of a polysiloxane anticorrosive coating as described in any one of claims 1 to 8 for corrosion protection of storage tanks in the petrochemical industry or steel structures in marine engineering.

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