阅读说明：本技术 一种水性复合涂层材料及其制备方法和应用 (Water-based composite coating material and preparation method and application thereof ) 是由 唐建振 吴光飞 余栋才 彭派潜 陈巧站 于 2019-09-05 设计创作，主要内容包括：本发明公开一种水性复合涂层材料及其制备方法和应用,该涂层材料由硅橡胶、硅烷单体、丙烯酸单体以及特殊的复合功能材料制备得到,不含有毒有机溶剂,对环境友好,且不自燃,施工便捷、综合性能优越,能在-40℃～250℃下长期使用,其物理性能也不发生改变。(The invention discloses a water-based composite coating material and a preparation method and application thereof, the coating material is prepared from silicon rubber, a silane monomer, an acrylic acid monomer and a special composite functional material, does not contain toxic organic solvent, is environment-friendly, does not self-ignite, is convenient and fast to construct, has excellent comprehensive performance, can be used for a long time at the temperature of minus 40-250 ℃, and does not change the physical performance.)

1. A preparation method of a water-based composite coating material, which comprises a main agent and an auxiliary agent, is characterized by comprising the following steps:

dissolving 107 silicon rubber by using a solvent 1, adding a catalyst and a vinyl trialkoxysilane monomer, and reacting to obtain an organic silicon intermediate material;

mixing the organic silicon intermediate material with an acrylate reaction monomer and a free radical initiator, heating and stirring for reaction, continuously reacting after neutralization, removing the solvent 1, increasing the stirring speed, adding a composite functional material, water and an auxiliary agent, and continuously stirring to obtain a water-based composite emulsion serving as a main agent; the composite functional material is prepared from an aluminum sol solution, hydroxyl-containing polysiloxane and alkyl orthosilicate;

and mixing the curing agent with the catalyst to obtain the auxiliary agent.

2. The preparation method of the water-based composite coating material as claimed in claim 1, wherein the mass ratio of the 107 silicone rubber, the vinyl alkoxy silane monomer and the acrylate reaction monomer is (20-45): (2-5): (2.5-12).

3. The preparation method of the water-based composite coating material according to claim 2, wherein the mass ratio of the composite functional material to 107 silicone rubber is (5-20): (20-45).

4. A method for preparing the aqueous composite coating material according to any one of claims 1 to 3, wherein the method for preparing the composite functional material comprises the following steps:

A. mixing aluminum alkyl alkoxide, water and acid, heating for reaction, removing the alkyl alcohol and the water to obtain a crystalline material, cooling, and adding an acidic aqueous solution to obtain an aluminum sol solution;

B. mixing hydroxyl-containing polysiloxane, a solvent 3 and a catalyst, dropwise adding alkyl orthosilicate, stirring at a low speed after dropwise adding, adding an emulsifier, stirring at a low speed, dropwise adding the alumina sol solution prepared in the step A while improving the stirring speed, stirring at a high speed for reaction after dropwise adding, removing the solvent 3 and alkyl alcohol after the reaction is finished, and adjusting the pH value to be neutral to obtain a composite functional material; the hydroxyl-containing polysiloxane is an alkyl polysiloxane having at least two silicon-bonded hydroxyl groups and/or an alkyl polysiloxane having at least two silicon-bonded alkylhydroxyl groups.

5. The preparation method of the water-based composite coating material according to claim 4, wherein in the preparation method of the composite functional material, the mass ratio of the hydroxyl-containing polysiloxane to the alkyl orthosilicate in the step B and the alumina sol solution prepared in the step A is as follows: (28-40):(4-7):(25-35).

6. The method for preparing the water-based composite coating material according to claim 4, wherein in the step B, the solvent 3 is one or more of absolute ethyl alcohol, acetone and ethyl acetate, and the mass ratio of the solvent 3 to the hydroxyl-containing polysiloxane is (0.8-2.5) to (1-1.2).

7. The method for preparing an aqueous composite coating material according to claim 4, wherein in the step B, the emulsifier is a surfactant having acidity in aqueous solution, and is an alkylbenzene sulfonic surfactant, a sulfonate surfactant, a sulfate surfactant or a phosphate surfactant.

8. The method for preparing the water-based composite coating material according to claim 4, wherein in the step B, the stirring speed is increased to 8000-12000 r/min, and the stirring speed of the high-speed stirring reaction is 8000-12000 r/min.

9. An aqueous composite coating material, which comprises a main agent and an auxiliary agent, and is prepared by the preparation method of any one of claims 1 to 4, wherein the solid content of the mixed main agent and the mixed auxiliary agent is 60 to 80 percent, and the viscosity at 25 ℃ is 5000-8000mpa.s.

10. A composite coating is prepared by mixing the main agent and the auxiliary agent in the water-based composite coating material of claim 9, coating, and curing at 80-120 ℃ for 1.5-2.5 h.

Technical Field

The invention relates to an aqueous environment-friendly composite coating material, in particular to an insulating, high and low temperature resistant and anti-corrosion aqueous composite coating material for protecting important parts of new energy automobiles such as motor coils, igniters, battery wire sheaths, spark plug sheaths and the like, and a preparation method and application thereof.

Technical Field

The average usage amount of the organic silicon material in the automobile is about 3.2 kg/automobile, the automobile sales amount in China can reach 3300 thousands in 2020, 210 thousands of new energy automobiles are estimated, the domestic market can reach more than 100 million yuan in 2020, the new energy automobile market can reach more than 10 million yuan, and the prospect is very good. At present, the water-based organic silicon material technology is monopolized by foreign companies, and no water-based organic silicon material can be used in the field of new energy automobiles, so that the research on the water-based organic silicon material technology is developed and creatively applied to new energy automobiles, the water-based organic silicon material technology is necessary for seizing the high point of the new energy automobile material technology and improving the domestic competitiveness, and the water-based organic silicon material technology has great significance for promoting the development of the new energy automobile material technology.

On the protection materials of important components of new energy automobiles such as motor coils, igniters, battery wire sheaths, spark plug sheaths and the like, the currently applied organic silicon materials are mainly solvent-based, and the materials have the problems of high VOC (volatile organic compound) emission and high-temperature curing and are extremely easy to self-ignite, namely are not environment-friendly and have potential safety hazards, while the protection materials obtained by organic silicon modified polyurethane, acrylic acid, alkyd resin and the like have low silicon content, cannot fully exert the characteristics of organic silicon and are limited in application.

Disclosure of Invention

In order to solve the problems in the prior art, the invention aims to provide a water-based composite coating material, a preparation method and application thereof, the water-based composite coating material does not contain toxic organic solvents, is environment-friendly, does not spontaneously combust, is convenient and fast to construct, has excellent comprehensive performance, has the effects of sealing, insulation, corrosion prevention, cold resistance, heat resistance protection, flame retardance and the like in practical application, can be used for a long time at the temperature of minus 40 ℃ to 250 ℃, and does not change the physical properties.

The technical scheme of the invention is as follows:

a preparation method of an aqueous composite coating material, wherein the aqueous composite coating material comprises a main agent and an auxiliary agent, and the preparation method comprises the following steps:

dissolving 107 silicon rubber by using a solvent 1, adding a catalyst and a vinyl trialkoxysilane monomer, and reacting to obtain an organic silicon intermediate material;

mixing the organic silicon intermediate material with an acrylate reaction monomer and a free radical initiator, heating and stirring for reaction, continuously reacting after neutralization, removing the solvent 1, increasing the stirring speed, adding a composite functional material, water and an auxiliary agent, and continuously stirring to obtain a water-based composite emulsion serving as a main agent; the composite functional material is prepared from an aluminum sol solution, hydroxyl-containing polysiloxane and alkyl orthosilicate;

and mixing the curing agent with the catalyst to obtain the auxiliary agent.

The 107 silicone rubber is hydroxyl-terminated polydimethylsiloxane (alpha, omega-dihydroxy polydimethylsiloxane), and the number average molecular weight of the 107 silicone rubber is preferably 5000-80000. The alkoxy in the vinyl trialkoxy silane monomer is C1-C5 alkoxy, preferably methoxy, ethoxy or isopropoxy.

The solvent 1 can dissolve 107 silicon rubber and is easy to distill off, and can be ethyl acetate, and the dosage ratio of the solvent 1 to the 107 silicon rubber is preferably (0.5-2): 1.

Preferably, the reaction of the 107 silicone rubber and the vinyl alkoxy silane monomer is carried out under the catalysis of a catalyst, and the reaction is carried out for 2-4 hours at the temperature of 50-70 ℃ with stirring, wherein the catalyst comprises an organic tin catalyst, specifically dibutyltin dilaurate, octylstannous and tin acetate, and the ratio of the usage amount of the catalyst to the vinyl alkoxy silane monomer is (0.05-0.1): 100. In the reaction of the step, part of 107 silicon rubber reacts to introduce vinyl, and reacts with acrylate monomers in subsequent reaction, so that part of 107 silicon rubber molecules are modified, and the modified substance plays a role in stabilizing and emulsifying 107 silicon rubber, so that the 107 silicon rubber is easy to emulsify and disperse.

The acrylate reaction monomer comprises alkyl (meth) acrylate, acrylic acid and hydroxyl (meth) acrylate, wherein the alkyl (meth) acrylate refers to alkyl methacrylate and/or alkyl acrylate, the (meth) acrylic acid refers to methacrylic acid and/or acrylic acid, the hydroxyl (meth) acrylate refers to hydroxyl methacrylate and/or hydroxyl acrylate, the hydroxyl (meth) acrylate is an ester obtained by reacting (meth) acrylic acid with alcohol, and the alcohol is C1-C5 alcohol, preferably ethanol. Preferably, the mass ratio of the alkyl (meth) acrylate, the (meth) acrylic acid and the hydroxyl (meth) acrylate is (2-10): (0.25-1): (0.25-0.5).

Preferably, the mass ratio of the 107 silicone rubber, the vinyl alkoxy silane monomer and the acrylate reaction monomer is (20-45): (2-5): (2.5-12).

The free radical initiator is a commonly used free radical initiator in the field of acrylic emulsion polymerization, and comprises azobisisobutyronitrile and the like, and the mass ratio of the free radical initiator to the mass of an acrylate reaction monomer is preferably (0.05-0.2): (2.5-11.5).

Preferably, the step of mixing the organosilicon intermediate material with the acrylate reaction monomer and the free radical initiator is to drop the organosilicon intermediate material into a mixed solution containing the acrylate reaction monomer and the free radical initiator, and the stirring speed is 200-400r/min in the operation of heating and stirring reaction; the dropwise adding process is carried out at 60-80 ℃, and after the dropwise adding is finished, the temperature is raised to 75-85 ℃, and the stirring reaction is carried out for 1.5-2 hours.

The solvent 1 is usually removed by distillation or distillation under reduced pressure. The neutralization is carried out by adding a neutralizing agent to adjust ph to 7-9, and the neutralizing agent is not particularly limited and includes N, N-dimethylethanolamine, ammonia water and the like.

Preferably, in the step of adding the composite functional material, water and the auxiliary agent, the mass ratio of the water to the 107 silicone rubber is (5-12): (4-9). The auxiliary agent is an auxiliary agent commonly used in the coating, and comprises a wetting agent, a defoaming agent, a leveling agent and the like, and the type and the using amount of specific substances are not particularly limited.

Preferably, the mass ratio of the composite functional material to 107 silicone rubber is (5-20): (20-45).

Preferably, in the step of increasing the stirring speed, adding the composite functional material, water and the auxiliary agent, and continuing stirring, the stirring speed is 1000-2000 r/min, the adding is in a dropwise adding mode, and after the dropwise adding is finished, the stirring is continued for 30-60 minutes at 1000-2000 r/min and 30-45 ℃, so that the dispersion rate is increased, and the floating oil and the layering can be reduced.

The curing agent is a substance capable of reacting with hydroxyl in 107 silicone rubber to crosslink 107 silicone rubber, and the specific substance is not particularly limited and includes one or more of methyltrimethoxysilane, aminopropyltriethoxysilane, gamma-methacryloxypropyltrimethoxysilane and 3-glycidyloxypropyltrimethoxysilane. Preferably, the mass ratio of the curing agent to the 107 silicone rubber is (0.8-1.2): 1. The catalyst is the same as the catalyst used in the step of reacting 107 silicon rubber with the vinyl alkoxy silane monomer, the substance type is not particularly limited, and the mass ratio of the mass to the curing agent is (0.1-0.5): (10-25).

Preferably, the preparation method of the composite functional material comprises the following steps:

A. mixing aluminum alkyl alkoxide, water and acid, heating for reaction, removing the alkyl alcohol and the water to obtain a crystalline material, cooling, and adding an acidic aqueous solution to obtain an aluminum sol solution;

B. mixing hydroxyl-containing polysiloxane, a solvent 3 and a catalyst, dropwise adding alkyl orthosilicate, stirring at a low speed after dropwise adding, adding an emulsifier, stirring at a low speed, dropwise adding the alumina sol solution prepared in the step A while improving the stirring speed, stirring at a high speed for reaction after dropwise adding, removing the solvent 3 and alkyl alcohol after the reaction is finished, and adjusting the pH value to be neutral to obtain a composite functional material; the hydroxyl-containing polysiloxane is an alkyl polysiloxane having at least two silicon-bonded hydroxyl groups and/or an alkyl polysiloxane having at least two silicon-bonded alkylhydroxyl groups.

Preferably, the aluminum alkyl alkoxide is aluminum isopropoxide or aluminum sec-butoxide.

In the step A, the alkyl alcohol is obtained by hydrolysis reaction of aluminum alkyl alcohol and is removed by evaporation and the like. The removal of alkyl alcohol and water is generally carried out by distillation under reduced pressure at a temperature of 80-90 ℃.

Preferably, the temperature rise reaction in the step A is carried out for 4-6 h when the temperature rises to 70-80 ℃.

Preferably, in the step A, the mass ratio of the aluminum alkyl alcohol to the water is (8-20): (70-100).

The acid is not particularly limited, and those skilled in the art can select the acid according to practical needs, preferably hydrochloric acid with a mass fraction of 37%, wherein the mass of the acid is 0.5-2% of the mass of water.

Preferably, in the step a, the pH of the acidic aqueous solution is 1 to 2.

In the step A, the solid content of the aluminum sol solution is Al in the aluminum sol solution₂O₃Preferably, the solid content of the aluminum sol solution is 15-30%.

In the preparation method of the composite functional material, the hydroxyl-containing polysiloxane is alkyl polysiloxane with at least two silicon-bonded hydroxyl groups and/or alkyl polysiloxane with at least two silicon-bonded alkyl hydroxyl groups, which can be linear or organopolysiloxane with certain branched structure, the hydroxyl groups and alkyl hydroxyl groups can be positioned at terminal position or on the side chain of the polysiloxane, and the product is not specially limited, and the product is commercially named as hydroxy silicone oil and alkyl hydroxyl silicone oil, wherein the alkyl groups are preferably C1-C4 alkyl groups, more preferably methyl groups, and the alkyl hydroxyl groups are preferably-CH 2OH, -CH2-CH2-CH2 OH. Preferably, the hydroxyl-containing polysiloxane has a number average molecular weight of 300-1000.

Preferably, the hydroxyl group content of the hydroxyl group-containing polysiloxane is 5 to 12% by mass. The molecular weight and the hydroxyl content directly influence the reactivity of substances and the performance of reaction products, the lower the molecular weight, the higher the hydroxyl activity, and the excellent scratch resistance is finally realized, but the toughness of the coating is insufficient, the lower the hydroxyl content, the insufficient crosslinking points are easy to generate in reaction, and the higher the molecular weight, the insufficient reactivity is generated, and the oil floating and the delamination are generated.

The test method for the medium hydroxyl group of the hydroxyl-containing polysiloxane of the present invention is as follows: determination of hydroxyl content in hydroxyl silicone oil by a volumetric method, namely Yaojian, Zhangjihong, Wangshupu, the chemical world, 1999, 13 (2): 53-54.

Preferably, in the step B, the reaction is performed under the protection of an inert gas, and the inert gas includes nitrogen.

Preferably, in the step B, the alkyl orthosilicate is ethyl orthosilicate or methyl orthosilicate.

Preferably, in the step B, the mass ratio of the hydroxyl-containing polysiloxane to the alkyl orthosilicate and the alumina sol solution prepared in the step a is as follows: (28-40):(4-7):(25-35).

In the step B, the solvent 3 is used for dissolving and diluting the hydroxyl-containing polysiloxane to control the reaction rate thereof, and the solvent 3 is also a solvent that can be distilled off to reduce the VOC content, and is not limited to a particular kind, including one or more of absolute ethyl alcohol, acetone, and ethyl acetate. Step B the alkyl alcohol is one of the reaction products of alkyl orthosilicate and hydroxyl-containing polysiloxane, the solvent 3 and the alkyl alcohol are removed by conventional distillation or reduced pressure distillation method, and the temperature of the distillation process needs to be controlled at 60-75 ℃ to effectively separate the alcohol and the solvent 3 from the system. Preferably, in the step B, the mass ratio of the solvent 3 to the hydroxyl-containing polysiloxane is (0.8-2.5): 1-1.2.

The catalyst in the step B can catalyze the polymerization reaction of the hydroxyl-containing polysiloxane and the alkyl orthosilicate, the type of the catalyst is not particularly limited, and the preferred catalyst is one or two of stannous octoate and stannous oleate. Preferably, in the step B, the mass ratio of the catalyst to the hydroxyl-containing polysiloxane is (0.5-2): 1000.

In the step B, the emulsifier is a surfactant whose aqueous solution has acidity, which can catalyze and promote hydrolysis of ethyl orthosilicate and has strong emulsifying property, and is preferably an alkylbenzene sulfonic surfactant, a sulfonate surfactant, a sulfate surfactant or a phosphate surfactant, specifically alkylbenzene sulfonate, α -olefin sulfonate, alkylsulfonate, α -sulfo monocarboxylic acid ester, fatty acid sulfoalkyl ester, succinate sulfonate, alkylnaphthalene sulfonate, petroleum sulfonate, lignosulfonate, fatty alcohol sulfate, secondary alkyl sulfate, nonylphenol polyoxyethylene ether phosphate, fatty alcohol polyoxyethylene ether phosphate, triphenylethylphenol polyoxyethylene ether phosphate or dodecylbenzene sulfonic acid. Preferably, in the step B, the mass of the emulsifier is 2-8% of that of the hydroxyl-containing polysiloxane.

Preferably, the low-speed stirring is carried out for 0.5-1 h at 20-30 ℃ after the dropwise adding in the step B is finished; the emulsifier is added and stirred at a low speed for 4-6 h at 20-30 ℃. In the step B, preferably, the stirring speed of low-speed stirring after the dropwise adding is finished is 200-1000 r/min, and the stirring speed of adding the emulsifier for low-speed stirring is 200-1000 r/min.

In the step B, preferably, the stirring speed is increased to 8000-12000 r/min. Preferably, the stirring speed of the high-speed stirring reaction is 8000-12000 r/min, and the reaction temperature is 20-35 ℃. Preferably, the high-speed stirring reaction time is 6-10 h. According to the invention, the cross-linking reaction of polysiloxane, alkyl silicate and aluminum sol is effectively controlled by optimizing the stirring conditions and process steps, and oil-water separation is avoided.

The composite functional material of the present invention is an aqueous emulsion, which contains a small amount of water, and the emulsion obtained through the emulsification step of step B is a stable water-in-oil emulsion, which can be phase-converted into an oil-in-water emulsion by further dropping water, which is a common practice in the art.

And B, adjusting the pH value in the step B, namely taking a water-in-oil emulsion sample, adding water to convert the phase of the water-in-oil emulsion sample into the water-in-oil emulsion, measuring the pH value, adding alkali liquor, sampling, adding an equal amount of water, measuring the pH value, and directly sampling and testing if the water-in-oil emulsion is the oil-in-water emulsion.

Preferably, the solid content of the composite functional material is 60-68%, and the viscosity at 25 ℃ is 1500-2500 mpa.s.

The water-based composite coating material comprises a main agent and an auxiliary agent, and is prepared by the preparation method, wherein the solid content of the mixed main agent and the mixed auxiliary agent is 60-80%, and the viscosity at 25 ℃ is 5000-.

A composite coating is prepared by mixing a main agent and an auxiliary agent in the water-based composite coating material, coating to form a coating, and curing at 80-120 ℃ for 1.5-2.5 h. The main agent and the auxiliary agent are preferably mixed, vacuumized, defoamed and coated, and the coating method includes spraying, dipping, brushing and the like, and the base material is not particularly limited and includes a glass fiber sleeve, an aluminum alloy and the like.

Compared with the prior art, the invention has the following beneficial effects:

1. 107 silicon rubber is selected as the main film forming substance of the invention, which provides good rebound resilience, flexibility and flexing resistance for the coating.

2. The organosilicon material system of the invention has extremely high silicon content, endows the paint film with good performances of sealing, insulation, corrosion prevention, cold resistance, heat-resistant protection, flame retardance and the like, can be used for a long time at the temperature of-40 ℃ to 250 ℃, and does not change the physical properties.

3. The organic silicon material system comprises a composite functional material, has a good reinforcing effect on a film forming material, improves the adhesive force of a paint film to a base material, and does not influence the application performance of the paint film.

4. The water-based organic silicon material disclosed by the invention does not contain toxic solvents, is environment-friendly, does not self-ignite, is convenient and fast to construct and has excellent comprehensive performance.

Detailed Description