A kind of aging-resistant organic silicon insulating waterproof coating and its preparation method and application

Abstract

The present invention belongs to the technical field of organic silicon coatings, and discloses an aging-resistant organic silicon insulating waterproof coating, a preparation method thereof, and an application thereof. The preparation method comprises the following steps: mixing a hydrogen-containing ring body with a vinyl silane coupling agent under the conditions of a silicon hydroaddition catalyst to obtain a cyclosiloxane crosslinker; uniformly mixing the obtained cyclosiloxane crosslinker with α,ω-dihydroxy polysiloxane, polydimethylsiloxane, dialkoxy epoxy silane coupling agent, fumed silica, an antistatic agent, a fluorine-containing silicone resin, a catalyst, and solvent oil under a protective atmosphere to obtain an aging-resistant organic silicon insulating waterproof coating. The present invention adopts a specific cyclosiloxane crosslinker compared to conventional alkoxysilane crosslinkers and ketoxime silane crosslinkers, which can significantly improve the mechanical properties, weather resistance, and storage stability of the obtained organic silicon coating.

Description

Technical Field

[0001] The present invention belongs to the technical field of organic silicon coatings, and in particular relates to an aging-resistant organic silicon insulating waterproof coating and a preparation method and application thereof. Background Art

[0002] Electricity meter boxes are used in harsh environments and require certain corrosion and rust resistance. Currently, appropriate surface treatment methods are generally used, such as applying a layer of insulating coating on the surface for surface modification. However, existing insulating coatings have poor aging and oxidation resistance, and the service life of the coated electricity meter boxes is limited. In order to reduce costs, increase the utilization rate of electricity meter boxes, and improve the safety factor, it is urgent to improve the surface treatment technology of electricity meter boxes.

[0003] Silicone coatings have promising applications in the surface treatment of electric meter boxes due to their excellent weather resistance, hydrophobicity, and insulation properties. Patent CN 105176387 A discloses an enhanced, solvent-free, heat-resistant silicone insulating varnish, prepared from the following components (by weight): 40-50 parts hydrogenated silicone oil, 44.996-49.994 parts modified hydroxy silicone oil, 5-10 parts modified nano-silica, and 0.004-0.006 parts chloroplatinum. This silicone insulating varnish utilizes addition-type silicone rubber and requires the preparation of a special modified hydroxy silicone oil, resulting in high costs. Patent CN 102559047 A discloses a silicone coating composed of dihydroxypolydimethylsiloxane, MQ resin, white carbon black, a vulcanization accelerator, methyltributylanoximesilane, vinyltributylanoximesilane, propylaminotriethoxysilane, 3-glycidoxypropyltrimethoxysilane, and a solvent. The use of deketoxime-type cross-linking agents is relatively expensive and corrosive to the copper substrate, which has a certain impact on its application.

[0004] Dealcoholized silicone rubber is widely used in silicone coatings due to its excellent adhesion to substrates after vulcanization, its non-corrosive properties, its excellent physical and mechanical properties, its electrical properties, and its low cost. Currently, the crosslinkers used in dealcoholized silicone coatings are generally small-molecule orthosilicates and trialkoxysilanes. However, these crosslinkers have a strong tendency to self-aggregate, resulting in a gradual loss of crosslinking properties during storage. Excessive self-aggregation also reduces the crosslinking strength of the hydroxyl polysiloxane matrix, significantly reducing the mechanical and weathering properties of the resulting coating. Summary of the Invention

[0005] In view of the shortcomings and deficiencies of the above prior art, the primary purpose of the present invention is to provide a method for preparing an aging-resistant organic silicon insulating waterproof coating.

[0006] Another object of the present invention is to provide an aging-resistant organic silicon insulating waterproof coating prepared by the above method.

[0007] Another object of the present invention is to provide an application of the above-mentioned aging-resistant silicone insulating waterproof coating in the surface treatment of power equipment.

[0008] The purpose of the present invention is achieved through the following technical solutions:

[0009] A method for preparing an aging-resistant organic silicon insulating waterproof coating comprises the following steps:

[0010] (1) mixing a hydrogen-containing ring body with a vinyl silane coupling agent under a hydrosilylation catalyst to obtain a cyclosiloxane crosslinking agent;

[0011] (2) The obtained cyclosiloxane crosslinking agent is mixed evenly with α,ω-dihydroxypolysiloxane, polydimethylsiloxane, dialkoxyepoxysilane coupling agent, fumed silica, antistatic agent, fluorine-containing silicone resin, catalyst and solvent oil under a protective atmosphere to obtain an aging-resistant silicone insulating waterproof coating.

[0012] Furthermore, the hydrogen-containing ring compound in step (1) is preferably tetramethylhydrogencyclotetrasiloxane (D4H) or pentamethylhydrogencyclopentasiloxane (D5H).

[0013] Furthermore, the molar ratio of the reaction of the hydrogen-containing ring body and the vinyl silane coupling agent in step (1) is preferably 1:2-5.

[0014] Furthermore, the vinyl silane coupling agent in step (1) is preferably vinyl trimethoxy silane or vinyl triethoxy silane.

[0015] Furthermore, the mixing reaction in step (1) is carried out under solvent-free conditions or anhydrous solvent conditions, and the anhydrous solvent is preferably one or a mixed solvent of two or more of ethanol, isopropanol, acetone, benzene, toluene, ethyl acetate, cyclohexane, dimethylformamide, and dimethyl sulfoxide.

[0016] Furthermore, the hydrosilylation catalyst in step (1) is an isopropanol solution of chloroplatinic acid (Speier catalyst) or a vinyl platinum complex (Karstedt's catalyst).

[0017] Furthermore, the temperature of the mixing reaction in step (1) is 70-90° C., and the time is 2-8 hours.

[0018] Furthermore, the viscosity of the α,ω-dihydroxy polysiloxane in step (2) is preferably 50 to 150 mPa·s (25° C.).

[0019] Furthermore, the viscosity of the polydimethylsiloxane in step (2) is preferably 1000 to 5000 mPa.s (25° C.).

[0020] Furthermore, the dialkoxy epoxy silane coupling agent in step (2) is at least one of γ-glycidyloxypropylmethyldimethoxysilane and γ-glycidyloxypropylmethyldiethoxysilane.

[0021] Furthermore, the antistatic agent in step (2) is preferably at least one of stearamidopropyl hydroxyethyl quaternary ammonium nitrate, alkyl dicarboxymethyl ammonium betaine, and dodecyl dimethyl quaternary betaine.

[0022] Furthermore, the fluorine-containing silicone resin in step (2) is preferably polymethyl nonafluorohexylsiloxane.

[0023] Furthermore, the catalyst in step (2) is preferably a compound of a titanate catalyst and an organotin catalyst.

[0024] Furthermore, the solvent oil in step (2) is preferably 120# solvent oil.

[0025] Furthermore, the weight proportions of the materials in step (2) are as follows:

[0026] 50-150 parts of α,ω-dihydroxypolysiloxane, 2-10 parts of polydimethylsiloxane, 1-5 parts of dialkoxyepoxysilane coupling agent, 20-40 parts of fumed silica, 0.2-2 parts of antistatic agent, 20-50 parts of fluorine-containing silicone resin, 2-5 parts of cyclosiloxane crosslinking agent, 0.01-0.05 parts of catalyst, and 100-300 parts of solvent oil.

[0027] An aging-resistant organic silicon insulating waterproof coating is prepared by the method.

[0028] Application of the above-mentioned aging-resistant silicone insulating waterproof coating in surface treatment of power equipment.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] The present invention adopts a specific cyclosiloxane crosslinking agent as the crosslinking agent of hydroxy silicone oil, and its synthesis route and molecular structure are as follows Figure 1As shown (under the condition that the molar ratio of D4H to vinyl silane coupling agent is 1:4). The crosslinking agent has a central structure of cyclosiloxane and an alkoxy dealcohol-type crosslinking structure distributed around it. The central structure of the cyclosiloxane can effectively enhance the reaction steric hindrance between the crosslinking agent molecules and enhance the compatibility with α,ω-dihydroxy polysiloxane. In addition, the increase in the number of alkoxy groups distributed around it is conducive to improving the reactivity with low-steric-hindered linear α,ω-dihydroxy polysiloxane. Through the above-mentioned combined effects, the self-polymerization tendency of the crosslinking agent is significantly reduced and the crosslinking efficiency with linear α,ω-dihydroxy polysiloxane is improved, thereby improving the storage stability of the resulting coating composition and improving the mechanical properties and weather resistance of the resulting coating film. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 The synthetic route of the cyclosiloxane crosslinking agent of the present invention is shown in FIG. DETAILED DESCRIPTION

[0032] The present invention will be further described in detail below with reference to examples, but the embodiments of the present invention are not limited thereto.

[0033] Example 1

[0034] A method for preparing an aging-resistant organic silicon insulating waterproof coating comprises the following steps:

[0035] (1) D4H and vinyltrimethoxysilane were added to a reactor in a molar ratio of 1:4 and mixed evenly. After nitrogen replacement, the temperature was raised to 70-80°C, Speier catalyst was added dropwise and stirred for 4 hours. The vinyl content in the product was sampled and the addition reaction rate was calculated to be 98.6%. The temperature was raised to 100-110°C and the residual solvent and unreacted raw materials were removed in vacuo to obtain a cyclosiloxane crosslinker.

[0036] (2) Weigh each component by weight, mix 4 parts of cyclosiloxane crosslinker with 100 parts of α,ω-dihydroxypolysiloxane with a viscosity of 100mPa.s, 6 parts of polydimethylsiloxane with a viscosity of 3000mPa.s, 3 parts of γ-glycidyloxypropylmethyldiethoxysilane, 30 parts of fumed silica, 1 part of stearamidopropyl hydroxyethyl quaternary ammonium nitrate, 30 parts of polymethyl nonafluorohexylsiloxane, 0.02 parts of dibutyltin dilaurate, 0.01 parts of tetraisopropyl titanate and 200 parts of 120# solvent oil under nitrogen protection to obtain an aging-resistant silicone insulating waterproof coating with a viscosity of 116mPa.s.

[0037] Example 2

[0038] A method for preparing an aging-resistant organic silicon insulating waterproof coating comprises the following steps:

[0039] (1) D4H and vinyltrimethoxysilane were added to a reactor in a molar ratio of 1:3 and mixed evenly. After nitrogen replacement, the temperature was raised to 75-85°C, Speier catalyst was added dropwise and stirred for 3 hours. The vinyl content in the product was sampled and the addition reaction rate was calculated to be 99.1%. The temperature was raised to 100-110°C and the residual solvent and unreacted raw materials were removed in vacuo to obtain a cyclosiloxane crosslinker.

[0040] (2) Weigh each component by weight, mix 5 parts of cyclosiloxane crosslinker with 150 parts of α,ω-dihydroxypolysiloxane with a viscosity of 150 mPa.s, 2 parts of polydimethylsiloxane with a viscosity of 1000 mPa.s, 3 parts of γ-glycidyloxypropylmethyldiethoxysilane, 40 parts of fumed silica, 1 part of stearamidopropyl hydroxyethyl quaternary ammonium nitrate, 20 parts of polymethyl nonafluorohexylsiloxane, 0.02 parts of dibutyltin dilaurate, 0.01 parts of tetraisopropyl titanate and 300 parts of 120# solvent oil under nitrogen protection to obtain an aging-resistant silicone insulating waterproof coating with a viscosity of 125 mPa.s.

[0041] Example 3

[0042] A method for preparing an aging-resistant organic silicon insulating waterproof coating comprises the following steps:

[0043] (1) D4H and vinyl triethoxysilane were added to a reactor in a molar ratio of 1:2 and mixed evenly. After nitrogen replacement, the temperature was raised to 80-90°C, Speier catalyst was added dropwise and stirred for 2 hours. The vinyl content in the product was sampled and the addition reaction rate was calculated to be 99.4%. The temperature was raised to 110-120°C and the residual solvent and unreacted raw materials were removed in vacuo to obtain a cyclosiloxane crosslinker.

[0044] (2) Weigh each component by weight, and mix 2 parts of cyclosiloxane crosslinker with 50 parts of α,ω-dihydroxypolysiloxane with a viscosity of 50mPa.s, 10 parts of polydimethylsiloxane with a viscosity of 5000mPa.s, 3 parts of γ-glycidyloxypropylmethyldiethoxysilane, 20 parts of fumed silica, 1 part of stearamidopropyl hydroxyethyl quaternary ammonium nitrate, 40 parts of polymethyl nonafluorohexylsiloxane, 0.02 parts of dibutyltin dilaurate, 0.01 parts of tetraisopropyl titanate and 100 parts of 120# solvent oil under nitrogen protection to obtain an aging-resistant silicone insulating waterproof coating with a viscosity of 132mPa.s.

[0045] Example 4

[0046] A method for preparing an aging-resistant organic silicon insulating waterproof coating comprises the following steps:

[0047] (1) D5H, vinyltrimethoxysilane and isopropanol solvent are added to a reactor and mixed evenly. The molar ratio of D5H to vinyltrimethoxysilane is 1:5, and the volume ratio of the added amount of isopropanol solvent to D5H is 1:1. After nitrogen substitution, the temperature is raised to 75-80°C, Speier catalyst is added dropwise and stirred for reaction for 5 hours. The vinyl content in the product is sampled and the addition reaction rate is calculated to be 97.9%. The temperature is raised to 100-110°C and the solvent and unreacted raw materials are removed in vacuo to obtain a cyclosiloxane crosslinker.

[0048] (2) Weigh each component by weight, mix 4 parts of cyclosiloxane crosslinker with 100 parts of α,ω-dihydroxypolysiloxane with a viscosity of 100mPa.s, 6 parts of polydimethylsiloxane with a viscosity of 3000mPa.s, 3 parts of γ-glycidyloxypropylmethyldiethoxysilane, 30 parts of fumed silica, 1 part of stearamidopropyl hydroxyethyl quaternary ammonium nitrate, 30 parts of polymethyl nonafluorohexylsiloxane, 0.02 parts of dibutyltin dilaurate, 0.01 parts of tetraisopropyl titanate and 200 parts of 120# solvent oil under nitrogen protection to obtain an aging-resistant silicone insulating waterproof coating with a viscosity of 115mPa.s.

[0049] Comparative Example 1

[0050] A method for preparing an aging-resistant organic silicon insulating waterproof coating. Compared with Example 1, the coating is prepared by using an equal amount of vinyltrimethoxysilane crosslinking agent instead of a cyclosiloxane crosslinking agent.

[0051] Comparative Example 2

[0052] A method for preparing an aging-resistant organic silicon insulating waterproof coating. Compared with Example 1, the coating is prepared by using an equal amount of vinyltributylanoxime silane crosslinking agent instead of a cyclosiloxane crosslinking agent.

[0053] The mechanical properties (GB / T 528-2009), weather resistance (mechanical property retention rate was tested after 600 hours of artificial weather aging (exposure to fluorescent ultraviolet light and water)) and storage stability (the coating sample was sealed and placed in an 80°C oven for accelerated aging for 48 hours, then taken out and placed under standard conditions (temperature 25°C, relative humidity 55%) for 24 hours to test the mechanical properties after curing) of the organic silicone insulating waterproof coatings obtained in the above examples and comparative examples. The results are shown in Table 1 below.

[0054] Table 1

[0055]

[0056] The results in Table 1 show that the specific cyclosiloxane crosslinking agent used in the present invention can significantly improve the mechanical properties, weather resistance and storage stability of the obtained silicone coating compared with conventional alkoxysilane crosslinking agents and ketoxime silane crosslinking agents.

[0057] The above embodiments are preferred implementations of the present invention, but the implementations of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be considered as equivalent replacement methods and are included in the scope of protection of the present invention.

Claims

1. A method for preparing an aging-resistant organic silicon insulating waterproof coating, characterized in that: The method comprises the following preparation steps: (1) mixing a hydrogen-containing ring body with a vinyl silane coupling agent under the conditions of a hydrosilylation catalyst to obtain a cyclosiloxane crosslinking agent; (2) uniformly mixing the obtained cyclosiloxane crosslinking agent with α,ω-dihydroxy polysiloxane, polydimethylsiloxane, dialkoxy epoxy silane coupling agent, fumed silica, antistatic agent, fluorine-containing silicone resin, catalyst and solvent oil under a protective atmosphere to obtain an aging-resistant organic silicone insulating waterproof coating; In step (1), the hydrogen-containing ring body is tetramethylhydrogencyclotetrasiloxane or pentamethylhydrogencyclopentasiloxane, and the vinyl silane coupling agent is vinyltrimethoxysilane or vinyltriethoxysilane; the molar ratio of the reaction of the hydrogen-containing ring body and the vinyl silane coupling agent is 1:2-5; The weight proportions of the materials in step (2) are as follows: 50-150 parts of α,ω-dihydroxypolysiloxane, 2-10 parts of polydimethylsiloxane, 1-5 parts of dialkoxyepoxysilane coupling agent, 20-40 parts of fumed silica, 0.2-2 parts of antistatic agent, 20-50 parts of fluorine-containing silicone resin, 2-5 parts of cyclosiloxane crosslinking agent, 0.01-0.05 parts of catalyst, 100-300 parts of solvent oil; The viscosity of the α,ω-dihydroxy polysiloxane at 25° C. is 50-150 mPa•s.

2. The method for preparing an aging-resistant organic silicon insulating waterproof coating according to claim 1, characterized in that: The mixed reaction in step (1) is carried out under solvent-free conditions or anhydrous solvent conditions, and the anhydrous solvent is one or a mixed solvent of two or more of ethanol, isopropanol, acetone, benzene, toluene, ethyl acetate, cyclohexane, dimethylformamide, and dimethyl sulfoxide.

3. The method for preparing an aging-resistant organic silicon insulating waterproof coating according to claim 1, characterized in that: The hydrosilylation catalyst in step (1) is a Speier catalyst or a Karstedt's catalyst; the temperature of the mixed reaction is 70-90° C., and the time is 2-8 hours.

4. The method for preparing an aging-resistant organic silicon insulating waterproof coating according to claim 1, characterized in that: The viscosity of the polydimethylsiloxane in step (2) at 25° C. is 1000-5000 mPa•s.

5. The method for preparing an aging-resistant organic silicon insulating waterproof coating according to claim 1, characterized in that: The dialkoxy epoxy silane coupling agent in step (2) is at least one of γ-glycidyloxypropylmethyldimethoxysilane and γ-glycidyloxypropylmethyldiethoxysilane; the antistatic agent is at least one of stearamidopropyl hydroxyethyl quaternary ammonium nitrate, alkyl dicarboxymethyl ammonium ethyl lactone, and dodecyl dimethyl quaternary ethyl lactone; the fluorine-containing silicone resin is polymethyl nonafluorohexylsiloxane; the catalyst is a compound of a titanate catalyst and an organic tin catalyst; and the solvent oil is 120# solvent oil.

6. An aging-resistant organic silicon insulating waterproof coating, characterized in that: It is prepared by the method according to any one of claims 1 to 5.

7. Use of the aging-resistant organic silicon insulating waterproof coating according to claim 6 in the surface treatment of power equipment.

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