A modified organic silicon resin aqueous dispersion and its preparation method and application

Abstract

The present invention relates to the technical field of resin coatings, and in particular to a modified silicone resin aqueous dispersion and a preparation method and application thereof, wherein the modified silicone resin aqueous dispersion is obtained by high-speed dispersion according to the following components in parts by weight: 200-300 parts of high acid value acrylic resin, 300-500 parts of silicone resin, 5-20 parts of amine neutralizer, and 300-650 parts of deionized water. The above-mentioned modified silicone resin aqueous dispersion is used as a film-forming substance, and a certain amount of water-based color paste and auxiliary agent, deionized water are added to prepare a high-temperature resistant coating that can be self-dried at room temperature or cured at high temperature, which can greatly reduce the volatile organic matter content in the current silicone high-temperature resistant paint. The paint film has good mechanical properties and excellent high-temperature resistance, and can be widely used in high-temperature resistant and anti-corrosion fields such as steam pipes, fireplaces, large boilers, and flues.

Description

Technical Field

[0001] The invention relates to the technical field of resin coatings, and in particular to a modified organic silicon resin aqueous dispersion and a preparation method and application thereof. Background Art

[0002] Organic silicon resin is mainly composed of Si-O-Si bonds with high bond energy. Its thermal oxidation stability is much higher than that of resins commonly used in coatings, and it has good high temperature resistance. When pure organic silicon resin is used as a film-forming substance in coatings, it often has problems such as poor mechanical properties, poor adhesion, and high temperature curing, which greatly limits its application range. Modification of silicone resins with acrylic resins, epoxy resins, polyester resins, etc. can broaden the application scope of silicone resins, such as patent document CN111019138A, a method for preparing acrylic and polyester modified silicone resins and their applications, which mentions acrylic resins and saturated polyester resin modified silicone resins and their self-drying high-temperature resistant coatings; CN107033296A, a method for preparing super-weather-resistant polysiloxane modified acrylic resins and topcoats, which mentions polysiloxane modified acrylic resins and their room-temperature curing weather-resistant topcoats. However, this type of traditional modified silicone resin is still mainly solvent-based and must be diluted with a large amount of organic solvents to achieve construction conditions, and cannot meet increasingly stringent environmental protection requirements; in CN114015307A, a one-component water-based acrylic strippable coating and its preparation method and application, the water-based high-temperature resistant coating prepared with silicone emulsion has good performance, but requires high temperature and long-term curing, which limits its application scope. How to prepare a water-based modified silicone resin, reduce the content of volatile organic matter in high-temperature resistant coatings, achieve room temperature curing or self-drying film formation, improve mechanical properties and adhesion, and broaden the application range of silicone high-temperature resistant coatings has become an urgent problem to be solved. The use of water-based acrylic modified silicone resins with high silicone content can better solve the above problems. For example, in CN110885630A silicone water-based high-temperature resistant special coatings and preparation methods, the room temperature self-drying high-temperature resistant coating prepared by mixing silicone emulsion and modified acrylic emulsion has good performance, but the stability of the two emulsions is usually poor after mixing. In the case of poor compatibility, phase separation is easily generated during room temperature self-drying or curing, which affects the performance of the paint film. In addition, due to the limitations of the emulsion characteristics, the gloss of the paint film is generally low. Summary of the invention

[0003] The purpose of the present invention is to solve the defects of the prior art, adopt conventional synthesis process to obtain silicone resin and high acid value acrylic resin with good compatibility, and after the two are blended, neutralized by amine, and dispersed at high speed by adding water to obtain a modified silicone resin aqueous dispersion with high silicone content, and then matched with high temperature resistant pigments, fillers, additives, etc. to provide a high temperature resistant coating. The principle is: the synthesized high acid value acrylic resin has a strong emulsification ability after being neutralized by amine, and the blended liquid is slowly added with water under high-speed stirring, and a modified silicone resin aqueous dispersion with stable state and high silicone content is obtained by phase inversion emulsification technology. The high acid value acrylic resin used has good mechanical properties, excellent adhesion to metal substrates, and excellent self-drying performance at room temperature, which makes up for the defects of silicone resin; the high temperature resistant coating prepared by the obtained modified silicone resin aqueous dispersion has low volatile organic matter content, can be self-dried at room temperature, and has excellent high temperature resistance.

[0004] In order to achieve the above-mentioned invention object, the present invention adopts the following technical solutions:

[0005] A modified organic silicon resin aqueous dispersion comprises the following components in parts by weight: 200-300 parts of acrylic resin, 300-500 parts of organic silicon resin, 5-20 parts of amine neutralizer and 300-650 parts of deionized water.

[0006] The acrylic resin is obtained by free radical polymerization of acrylic acid (ester) monomers in a solvent, wherein the acrylic acid (ester) monomers are selected from at least four of isooctyl acrylate, methyl methacrylate, hydroxyethyl methacrylate, hydroxyethyl acrylate, methacrylic acid, acrylic acid, and hydroxyethyl methacrylate phosphate; the initiator is selected from at least one of benzoyl peroxide, tert-butyl perbenzoate, and tert-butyl peroxydiethylhexanoate; and the solvent is selected from at least one of ethylene glycol monobutyl ether, propylene glycol methyl ether, n-butanol, and 100# solvent oil.

[0007] The organic silicone resin is prepared by hydrolysis-polycondensation reaction of organic siloxane monomers, wherein the organic siloxane monomers are selected from at least two of methyltrimethoxysilane, phenyltrimethoxysilane, dimethyldiethoxysilane, diphenyldimethoxysilane, and vinyltrimethoxysilane, and the catalyst is selected from any two of concentrated hydrochloric acid, hydrofluoric acid, and glacial acetic acid.

[0008] The amine neutralizer is selected from any one of triethylamine, N,N-dimethylethanolamine and ammonia water.

[0009] The preparation method of the acrylic resin is as follows:

[0010] 1) Add part of the above one or more solvents into the reactor, and heat it to 80-140°C with nitrogen;

[0011] 2) After mixing part of the above one or more initiators with acrylic acid (ester) monomer and part of the solvent, evenly add them dropwise into the reactor over a period of 3-5 hours;

[0012] 3) After the addition is completed, add some initiator, keep the temperature at 80-140℃ for 0.5-1h, then add some initiator again. After the addition is completed, react at 80-140℃ for 3-5h, cool to below 80℃, add some solvent to adjust the solid content to 45-55%, the viscosity to 5000-15000mPa•s, and the acid value to 20-40mgKOH / g.

[0013] The preparation method of the organosilicon resin is as follows:

[0014] After adding the organosiloxane monomer and catalyst into the reactor and mixing evenly, slowly add deionized water, raise the temperature to 60-75℃ for hydrolysis for 3-5h, slowly raise the temperature to distill out the alcohol and water produced by the hydrolysis and polycondensation of the organosiloxane, and stop the reaction when the resin viscosity reaches 2000-10000mPa•s and the solid content reaches 80-95%.

[0015] The method for preparing the modified silicone resin aqueous dispersion comprises the following steps, measured in parts by weight:

[0016] Heat 200-300 parts of acrylic resin and 300-500 parts of silicone resin to 30-60℃ and mix them evenly; add 5-20 parts of amine neutralizer at a stirring speed of 300-600r / min and neutralize for 10-30min; adjust the speed to 800-1200r / min, slowly add 300-650 parts of deionized water for 0.5-2h; after the deionized water is added, continue to disperse at a speed of 800-1200r / min for 0.5-1.5h; after the dispersion is completed, adjust the speed to 200-400r / min and continue stirring for 2h to eliminate bubbles generated during dispersion, and adjust the solid content to 35-45% and the viscosity ≤1000mPa•s with deionized water.

[0017] A coating comprises the following components in parts by weight: 30-50 parts of the modified silicone resin aqueous dispersion, 30-50 parts of water-based color paste, 0.1-0.3 parts of BYK333 wetting and leveling agent, 0.2-0.5 parts of Deqian FA179 anti-flash rust agent, 0.1-0.5 parts of Gel0620 thickener, and 0-3 parts of ethylene glycol monobutyl ether.

[0018] The water-based color paste is obtained by grinding the following components in parts by weight: 20-40 parts of deionized water, 1-5 parts of ethylene glycol monobutyl ether, 1-4 parts of BYK190 dispersant, 0.1-0.3 parts of BYK016 defoamer, 5-20 parts of copper chrome black, 5-20 parts of glass powder, 10-30 parts of talc powder, and 10-30 parts of mica powder.

[0019] Compared with the prior art, the modified silicone resin aqueous dispersion of the present invention and its preparation method and application have the following advantages:

[0020] The silicone resin is blended and modified with a high-acid value acrylic resin, and the modified silicone resin aqueous dispersion is obtained after amine neutralization and high-speed dispersion. The preparation method is simple, and the amount of silicone resin can be flexibly adjusted to meet different heat resistance requirements; the modified silicone resin aqueous dispersion paint film has good mechanical properties, high gloss, excellent adhesion to metal substrates, and good self-drying performance at room temperature, which makes up for the defects of high curing temperature and poor mechanical properties of single silicone resin, and broadens the application scope of silicone high-temperature resistant coatings; when used in high-temperature resistant coatings, it greatly reduces the emission of volatile organic compounds, and the coating film has excellent heat resistance. DETAILED DESCRIPTION

[0021] In order to more clearly describe the technical solutions and beneficial effects of the present invention, the present invention is further described in detail below in conjunction with embodiments.

[0022] Preparation Example 1 of High Acid Value Acrylic Resin:

[0023] 90.0g of propylene glycol methyl ether and 90.0g of 100# solvent oil were added to the reactor, and the temperature was raised to 126-130°C through nitrogen; 50.0g of isooctyl acrylate, 200.0g of methyl methacrylate, 20.0g of hydroxyethyl acrylate, 25.0g of methacrylic acid, 2.0g of hydroxyethyl methacrylate phosphate, 1.3g of tert-butyl peroxybenzoate, 1.5g of tert-butyl peroxydiethylhexanoate, propylene glycol 50.0g of methyl ether was mixed evenly and then added dropwise to the reactor for 4 hours; after the addition was completed, 0.5g of tert-butyl peroxydiethylhexanoate and 5g of propylene glycol methyl ether were added; after keeping at 126-130℃ for 1 hour, 0.5g of tert-butyl peroxydiethylhexanoate and 5g of propylene glycol methyl ether were added again; after keeping at 126-130℃ for 4 hours, after the insulation was completed, the temperature was lowered to below 80℃, 110g of 100# solvent oil was added for dilution. The resin viscosity was 6000-6500mPa•s, the solid content was 46.1%, and the acid value was 26.5mgKOH / g.

[0024] Preparation Example 2 of High Acid Value Acrylic Resin:

[0025] 54.0g of ethylene glycol monobutyl ether and 77.0g of 100# solvent oil were added to the reactor, and the temperature was raised to 136-140°C through nitrogen; 77.0g of isooctyl acrylate, 183.0g of methyl methacrylate, 23.0g of hydroxyethyl methacrylate, 25.0g of methacrylic acid, 2.7g of hydroxyethyl methacrylate phosphate, 2.3g of tert-butyl perbenzoate and 45.0g of ethylene glycol monobutyl ether were mixed evenly and added dropwise to the reactor for 3h; after the addition was completed, 0.4g of tert-butyl perbenzoate and 8.0g of ethylene glycol monobutyl ether were added; after keeping warm at 136-140°C for 0.5h, 0.4g of tert-butyl perbenzoate and 8.0g of ethylene glycol monobutyl ether were added again; after keeping warm at 136-140°C for 3h, after the insulation was completed, the temperature was lowered to below 80°C, 115.0g of 100# solvent oil was added for dilution. Resin viscosity is 7000-9000mPa•s, solid content is 50.2%, and acid value is 28.3mgKOH / g.

[0026] Preparation Example 3 of High Acid Value Acrylic Resin:

[0027] 100.0g of n-butanol and 100# solvent oil were added to the reactor, and the temperature was raised to 116-120°C by nitrogen; 100.0g of isooctyl acrylate, 250.0g of methyl methacrylate, 30.0g of hydroxyethyl methacrylate, 25.0g of acrylic acid, 3.0g of hydroxyethyl methacrylate phosphate, 3.0g of benzoyl peroxide, 3.0g of tert-butyl peroxydiethylhexanoate and 50.0g of n-butanol were mixed evenly and then added dropwise to the reactor for 4h; after the addition was completed, 0.5g of tert-butyl peroxydiethylhexanoate and 5.0g of n-butanol were added; after keeping warm at 116-120°C for 0.5h, 0.5g of tert-butyl peroxydiethylhexanoate and 5.0g of n-butanol were added again; the temperature was kept warm at 116-120°C for 3h, and after the insulation was completed, the temperature was lowered to below 80°C, 100g of 100# solvent oil was added for dilution. The resin viscosity is 12000-13000mPa•s, the solid content is 53.2%, and the acid value is 26.8mgKOH / g.

[0028] Preparation Example 4 of Silicone Resin:

[0029] 125.0 g of methyltrimethoxysilane, 130.0 g of phenyltrimethoxysilane, 25.0 g of dimethyldiethoxysilane, 35.0 g of diphenyldimethoxysilane, 30.0 g of vinyltrimethoxysilane, 0.03 g of concentrated hydrochloric acid and 2.0 g of acetic acid were put into a reaction kettle and mixed evenly; 60.0 g of deionized water was slowly added, and the temperature was raised to 66-70°C and kept warm for 4 hours; the temperature was slowly raised to distill out the alcohol and water produced by the hydrolysis and condensation of the organosiloxane, and the resin viscosity when the temperature was raised to 86°C was 2200-2600 mPa•s and the solid content was 88.9%.

[0030] Preparation Example 5 of Silicone Resin:

[0031] 175.0 g of methyltrimethoxysilane, 150.0 g of phenyltrimethoxysilane, 50.0 g of diphenyldimethoxysilane, 0.05 g of hydrofluoric acid and 2.5 g of acetic acid were put into a reaction kettle and mixed evenly; 65.0 g of deionized water was slowly added, and the temperature was raised to 70-72°C and kept warm for 3 hours; the temperature was slowly raised to distill out the alcohol and water produced by the hydrolysis and condensation of the organosiloxane, and the resin viscosity when the temperature was raised to 82°C was 8300-8500 mPa•s and the solid content was 85.8%.

[0032] Preparation Example 6 of Silicone Resin:

[0033] 100.0 g of methyltrimethoxysilane, 150.0 g of phenyltrimethoxysilane, 75.0 g of dimethyldiethoxysilane, 50.0 g of diphenyldimethoxysilane, 0.05 g of concentrated hydrochloric acid and 2.0 g of acetic acid were put into a reaction kettle and mixed evenly; 60.5 g of deionized water was slowly added, and the temperature was raised to 68-72°C and kept warm for 4 hours; the temperature was slowly raised to distill out the alcohol and water produced by the hydrolysis and condensation of the organosiloxane, and the resin viscosity when the temperature was raised to 92°C was 3000-3400 mPa•s and the solid content was 92.3%.

[0034] Preparation Example 7 of Water-Based Color Paste:

[0035] Mix 34.3g of deionized water, 3.0g of ethylene glycol monobutyl ether, 2.5g of BYK190 dispersant, and 0.2g of BYK016 defoamer evenly; add 12.5g of copper chrome black, 12.5g of glass powder, 17.5g of talcum powder, and 17.5g of mica powder under stirring; after all the materials are mixed evenly, grind the materials to a fineness of ≤20μm.

[0036] Preparation Example 8 of Water-Based Color Paste:

[0037] Mix 35.8g of deionized water, 2.0g of ethylene glycol monobutyl ether, 2.0g of BYK190 dispersant, and 0.2g of BYK016 defoamer evenly; add 12.5g of copper chrome black, 17.5g of glass powder, 17.5g of talcum powder, and 12.5g of mica powder under stirring; after all the materials are mixed evenly, grind the materials to a fineness of ≤20μm.

[0038] Example 1

[0039] 280.0g of high acid value acrylic resin in Preparation Example 2 and 460.0g of silicone resin in Preparation Example 4 were stirred and heated to 40°C; the dispersion speed was adjusted to 500r / min, 12.4g of N,N-dimethylethanolamine was added and stirred for 15min; the dispersion speed was adjusted to 1000r / min, 640.0g of deionized water was dripped for 1.0h, and after the dripping was completed, it was dispersed for 45min; the dispersion speed was adjusted to 400r / min and continued to stir for 2h to eliminate bubbles generated during dispersion, and a modified silicone resin dispersion with a solid content of 39.9% and a viscosity of 120-180mPa•s was obtained. The silicone resin content was 74.4% based on solid content.

[0040] 5.0 g of deionized water, 0.2 g of GEL0620 thickener, 0.2 g of BYK333 wetting and leveling agent, and 0.2 g of Deqian FA179 anti-flash rust agent are mixed evenly, added to 40.0 g of the aqueous color paste of Preparation Example 7 and 40.0 g of the above-mentioned modified silicone resin dispersion, and stirred thoroughly to obtain a high temperature resistant coating.

[0041] The finished coating is diluted with water and sprayed onto the cold-rolled steel plate. Its test performance is as follows:

[0042]

[0043] Example 2

[0044] 300.0g of high acid value acrylic resin in Preparation Example 1 and 305.0g of silicone resin in Preparation Example 6 were stirred and heated to 45°C; the dispersion speed was adjusted to 600r / min, 15.0g of triethylamine was added and stirred for 20min; the dispersion speed was adjusted to 1200r / min, 600.0g of deionized water was dripped for 1.0h, and after the dripping was completed, it was dispersed for 1h; the dispersion speed was adjusted to 350r / min and continued to stir for 2h to eliminate bubbles generated during dispersion, and a modified silicone resin dispersion with a solid content of 34.6% and a viscosity of 800-950mPa•s was obtained. The silicone resin content was 67.0% based on solid content.

[0045] 5.0 g of deionized water, 0.1 g of GEL0620 thickener, 0.2 g of BYK333 wetting and leveling agent, and 0.2 g of Deqian FA179 anti-flash rust agent are mixed evenly, added to 40.0 g of the aqueous color paste of Preparation Example 8 and 50.0 g of the above-mentioned modified silicone resin dispersion, and stirred thoroughly to obtain a high temperature resistant coating.

[0046] The finished coating is diluted with water and sprayed onto the cold-rolled steel plate. Its test performance is as follows:

[0047]

[0048] Example 3

[0049] 250.0g of high acid value acrylic resin in Preparation Example 3 and 340.0g of silicone resin in Preparation Example 5 were stirred and heated to 30°C; the dispersion speed was adjusted to 600r / min, and 10.0g of ammonia water was added for 10min; the dispersion speed was adjusted to 1200r / min, 300.0g of deionized water was dripped for 0.5h, and dispersed for 1h after the dripping was completed; the dispersion speed was adjusted to 300r / min and continued to stir for 2h to eliminate bubbles generated during dispersion, and a modified silicone resin dispersion with a solid content of 47.6% and a viscosity of 700-800mPa•s was obtained. The silicone resin content was 68.6% based on solid content.

[0050] 15.0 g of deionized water, 0.3 g of GEL0620 thickener, 0.2 g of BYK333 wetting and leveling agent, and 0.2 g of Deqian FA179 anti-flash rust agent are mixed evenly, added to 40.0 g of the aqueous color paste of Preparation Example 7 and 35.0 g of the above-mentioned modified silicone resin dispersion, and stirred thoroughly to obtain a high temperature resistant coating.

[0051] The finished coating is diluted with water and sprayed onto the cold-rolled steel plate. Its test performance is as follows:

[0052]

[0053] The applicant declares that the above is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention shall fall within the protection scope and disclosure scope of the present invention.

Claims

1. A modified silicone resin aqueous dispersion, characterized in that: The invention comprises the following components in parts by weight: 200-300 parts of acrylic resin, 300-500 parts of silicone resin, 5-20 parts of amine neutralizer, and 300-650 parts of deionized water; the acrylic resin is obtained by free radical polymerization of acrylic acid (ester) monomer in a solvent, the acrylic acid (ester) monomer is selected from at least four of isooctyl acrylate, methyl methacrylate, hydroxyethyl methacrylate, hydroxyethyl acrylate, methacrylic acid, acrylic acid, and hydroxyethyl methacrylate phosphate; the initiator is selected from at least one of benzoyl peroxide, tert-butyl perbenzoate, and tert-butyl peroxydiethylhexanoate; the solvent is selected from at least one of ethylene glycol monobutyl ether, propylene glycol methyl ether, n-butanol, and 100# solvent oil; The preparation method of the acrylic resin is as follows: 1) Add part of the one or more solvents into the reaction kettle, and heat it to 80-140° C. by nitrogen; 2) After uniformly mixing part of the one or more initiators, acrylic acid (ester) monomers and part of the solvent, uniformly dropwise add the mixture into the reaction kettle over a period of 3-5 hours; 3) After the addition is completed, add some initiator, keep the temperature at 80-140℃ for 0.5-1h, then add some initiator again. After the addition is completed, react at 80-140℃ for 3-5h, cool to below 80℃, add some solvent to adjust the solid content to 45-55%, the viscosity to 5000-15000mPa•s, and the acid value to 20-40mgKOH / g.

2. The modified silicone resin aqueous dispersion according to claim 1, characterized in that: The organic silicone resin is prepared by hydrolysis-polycondensation reaction of organic siloxane monomers, wherein the organic siloxane monomers are selected from at least two of methyltrimethoxysilane, phenyltrimethoxysilane, dimethyldiethoxysilane, diphenyldimethoxysilane, and vinyltrimethoxysilane, and the catalyst is selected from any two of concentrated hydrochloric acid, hydrofluoric acid, and glacial acetic acid.

3. The modified silicone resin aqueous dispersion according to claim 1, characterized in that: The amine neutralizer is selected from any one of triethylamine, N,N-dimethylethanolamine and ammonia water.

4. The modified silicone resin aqueous dispersion according to claim 2, characterized in that: The preparation method of the organosilicon resin is as follows: After adding the organosiloxane monomer and catalyst into the reactor and mixing evenly, slowly add deionized water, raise the temperature to 60-75℃ for hydrolysis for 3-5h, slowly raise the temperature to distill out the alcohol and water produced by the hydrolysis and polycondensation of the organosiloxane, and stop the reaction when the resin viscosity reaches 2000-10000mPa•s and the solid content reaches 80-95%.

5. The method for preparing the modified silicone resin aqueous dispersion according to any one of claims 1 to 4, characterized in that: The method comprises the following steps, measured by weight: Heat 200-300 parts of acrylic resin and 300-500 parts of silicone resin to 30-60℃ and mix them evenly; add 5-20 parts of amine neutralizer at a stirring speed of 300-600r / min and neutralize for 10-30min; adjust the speed to 800-1200r / min, slowly add 300-650 parts of deionized water for 0.5-2h; after the deionized water is added, continue to disperse at a speed of 800-1200r / min for 0.5-1.5h; after the dispersion is completed, adjust the speed to 200-400r / min and continue stirring for 2h to eliminate bubbles generated during dispersion, and adjust the solid content to 35-45% and the viscosity ≤1000mPa•s with deionized water.

6. A coating, characterized in that: The composition comprises the following components in parts by weight: 30-50 parts of the modified silicone resin aqueous dispersion prepared by the method of claim 5, 30-50 parts of water-based color paste, 0.1-0.3 parts of BYK333 wetting and leveling agent, 0.2-0.5 parts of Deqian FA179 anti-flash rust agent, 0.1-0.5 parts of Gel0620 thickener, and 0-3 parts of ethylene glycol monobutyl ether.

7. The coating according to claim 6, characterized in that The water-based color paste is obtained by grinding the following components in parts by weight: 20-40 parts of deionized water, 1-5 parts of ethylene glycol monobutyl ether, 1-4 parts of BYK190 dispersant, 0.1-0.3 parts of BYK016 defoamer, 5-20 parts of copper chrome black, 5-20 parts of glass powder, 10-30 parts of talc powder, and 10-30 parts of mica powder.

Images