Epoxy siloxane modified acrylic resin and method for preparing a topcoat

Abstract

The application discloses an epoxy siloxane modified acrylic resin and a preparation method of a topcoat. The resin is prepared by using styrene, methyl methacrylate, butyl acrylate, acrylic acid, vinyl triisopropoxy silane and the like as monomers, using di-tert-butyl peroxide as an initiator, using beta-(3,4-epoxycyclohexyl) ethyl triethoxysilane and gamma-glycidyl ether propyl trimethoxysilane as modifiers, using specific raw material ratios, and using a chemical synthesis modification method under catalyst conditions to synthesize the epoxy polysiloxane modified acrylic resin. The resin is used as a base material, and is combined with pigments, fillers, solvents and additives to prepare paint through dispersion, grinding and other processes. Compared with pure silicone resin, the epoxy siloxane modified acrylic resin has a cost advantage, is a single-component coating compared with common silicone modified acrylic resin, has the characteristics of simple construction process, and the paint film has a long service life and more durable weather resistance after moisture curing.

Description

Technical Field

[0001] This invention belongs to the field of coating technology, specifically relating to an epoxy siloxane modified acrylic resin and a method for preparing a topcoat. Background Technology

[0002] Currently, alkyd resins and acrylic resins are commonly used in outdoor weather-resistant coatings, with their weather resistance lasting approximately 2-3 years. Organosilicon siloxane resins have a Si-O-Si main chain. Because the bond energy of the Si-O bond (450 kJ / mol) is greater than that of the C-C bond (345 kJ / mol) and CO bond (351 kJ / mol) in ordinary organic polymers, siloxane resins exhibit excellent heat resistance and UV aging resistance. Pure organosilicon resins are relatively expensive, so alkyd and acrylic resins are often used to modify them. Siloxanes and acrylic resins have good miscibility; therefore, polysiloxanes containing active groups (such as -OH) are often condensed with acrylic resins containing active groups (such as -OH, -COOH) to combine the weather resistance and adhesion properties of both.

[0003] Commercially available siloxane-modified acrylic resin coatings typically have a service life of 5-8 years before the paint film begins to rust and become damaged. Conventional siloxane-modified acrylic resins modified using the methods described above generally require the use of a curing agent, resulting in two-component coatings with relatively cumbersome application processes. Currently, due to high labor costs and the environmental pollution and safety / environmental issues caused by frequent coating applications and maintenance, epoxy polysiloxane-modified acrylic resin coatings, with their simpler application process, longer service life, and superior weather resistance, are gaining popularity. Summary of the Invention

[0004] The purpose of this invention is to provide a method for preparing epoxy siloxane-modified acrylic resin and topcoat, addressing the problems existing in the above-mentioned technologies.

[0005] The objective of this invention can be achieved through the following technical solutions:

[0006] A high-performance epoxy-siloxane modified acrylic resin, comprising the following components in parts by weight:

[0007]

[0008]

[0009] In the above technical solution: the resin is composed of 36-55 parts of acrylate monomers, 2-6 parts of vinyltriisopropoxysilane, 1.5-2.5 parts of initiator, 1-5 parts of epoxysiloxane, 0.08-0.2 parts of catalyst and 20-25 parts of solvent;

[0010] Preferably, the acrylate monomers are styrene, methyl methacrylate, butyl acrylate and acrylic acid in a mass ratio of 5-8:20-30:10-18:0.5-1.

[0011] In the above technical solution, the initiator is selected from one or more of di-tert-butyl peroxide and dicumyl peroxide.

[0012] In the above technical solution: the epoxy siloxane is selected from one or more of β-(3,4-epoxycyclohexyl)ethyltriethoxysilane and γ-glycidyl etherpropyltrimethoxysilane;

[0013] Preferably, the epoxy siloxane is β-(3,4-epoxycyclohexyl)ethyltriethoxysilane or γ-glycidyl etherpropyltrimethoxysilane in a mass ratio of 1-2.5:0.5-1.2.

[0014] In the above technical solution: the catalyst is selected from one or more of triethylamine and triethanolamine;

[0015] Preferably, the catalyst is triethylamine and triethanolamine in a mass ratio of 0.03-0.06:0.07-0.2.

[0016] A method for preparing the above-mentioned epoxy-siloxane modified acrylic resin, the method comprising the following steps:

[0017] Step 1: Nitrogen gas is introduced into the reaction flask, and part of the solvent of the components is added into the reaction flask. The mixture is heated and refluxed to remove water. Then the temperature is lowered to 120-130℃, and the mixture of acrylate monomers and part of the initiator is slowly and evenly added. The reaction is maintained at this temperature for 1-3 hours.

[0018] Step 2: Mix vinyltriisopropoxysilane with the remaining solvent and initiator evenly, and slowly and evenly add it to the reaction flask at a temperature of 120-130℃. After the addition is complete, continue to keep the temperature for 1-3 hours. Add the epoxy siloxane and catalyst to the reaction flask at the same temperature, and continue to keep the temperature for the reaction until the acid value is <5mgKOH / g and the reaction is completed. The epoxy siloxane modified acrylic resin can then be obtained.

[0019] A weather-resistant topcoat made from an epoxy-siloxane-modified acrylic resin prepared by the above method, the composition of which is as follows:

[0020]

[0021] The pigment is selected from one or more of titanium dioxide, barium sulfate, iron oxide series, aluminum powder, zinc oxide, etc.; the additive is selected from at least one of pigment wetting and dispersing agents, leveling agents, UV stabilizers and UV absorbers; the solvent is xylene.

[0022] In the technical solution of this invention: the epoxy siloxane modified acrylic resin is 40-60 parts, the pigment is 15-30 parts, the additive is 0.1-1 parts, and the solvent is 8-12 parts.

[0023] A method for preparing a topcoat using the above-mentioned epoxy siloxane-modified acrylic resin as a base material, wherein the epoxy siloxane-modified acrylic resin is mixed evenly with the required pigments, fillers, additives, and solvents, dispersed, ground to a fineness of less than 20 micrometers, filtered, and packaged to obtain the finished epoxy siloxane-modified acrylic topcoat.

[0024] The beneficial effects of this invention are:

[0025] This resin uses styrene, methyl methacrylate, butyl acrylate, acrylic acid, and vinyltriisopropoxysilane as monomers, di-tert-butyl peroxide as an initiator, and β-(3,4-epoxycyclohexyl)ethyltriethoxysilane and γ-glycidyl etherpropyltrimethoxysilane as modifiers. Through chemical synthesis and modification under catalytic conditions, epoxy polysiloxane-modified acrylic resin is synthesized using a specific raw material ratio. Using this resin as a base material, it is combined with pigments, fillers, solvents, and additives, and then dispersed and ground to produce paint. The epoxy polysiloxane-modified acrylic resin described in this invention has a cost advantage over pure silicone resin. Compared with ordinary silicone-modified acrylic resin, it is a single-component coating with simple application processes. After moisture curing, the paint film has a long service life and more durable weather resistance. Detailed Implementation

[0026] The present invention will be further described below with reference to embodiments, but the scope of protection of the present invention is not limited thereto:

[0027] The formulation components and their mass percentages used in the epoxy siloxane modified acrylic resin of this invention are shown in Table 1.

[0028] The preparation methods of the epoxy-siloxane modified acrylic resin in Examples 1 to 3 of this invention are as follows:

[0029] Nitrogen gas was bubbled into the reaction flask for 10 minutes. A portion of the xylene solvent from the components was then added to the reaction flask, and the mixture was heated and refluxed to remove water. After complete water removal, the temperature was lowered to 125°C and maintained constant. The styrene, methyl methacrylate, butyl acrylate, acrylic acid, and other acrylate monomers from the components, along with a portion of the di-tert-butyl peroxide initiator, were mixed thoroughly. This mixture of acrylate monomers and initiator was then slowly and uniformly added at 125°C, and the reaction was maintained at this temperature for 2 hours.

[0030] Vinyltriisopropoxysilane was mixed thoroughly with the remaining xylene solvent and di-tert-butyl peroxide initiator, and then slowly and uniformly added to the reaction flask at 125°C. After the addition was complete, the temperature was maintained for 2 hours. β-(3,4-epoxycyclohexyl)ethyltriethoxysilane, γ-glycidyl ether propyltrimethoxysilane, and the catalysts triethylamine and triethanolamine were then added to the reaction flask at the same temperature. The reaction was maintained until the acid value was <5 mg KOH / g, thus obtaining epoxysiloxane-modified acrylic resin.

[0031] Table 1

[0032]

[0033] The specific parameters of the prepared epoxysiloxane modified acrylic resin are shown in Table 2.

[0034] Table 2

[0035] 1 Clarity and transparency Clear and transparent Clear and transparent Clear and transparent 2 Color (Fe-Co method), number 2 2 2 3 Viscosity (Greek tube / 25℃), s 52 47 56 4 Acid value, mgKOH / g 3.7 4.1 3.5 5 Fineness, μm 15 15 15

[0036] Example 4: 60% of the epoxy-siloxane modified acrylic resin prepared in Example 1 was mixed with 20% rutile titanium dioxide, 10% zinc oxide, 9.4% xylene solvent, 0.5% dispersant, and 0.1% defoamer until homogeneous. The mixture was dispersed, ground, and then filtered and packaged to obtain the finished epoxy-siloxane modified acrylic weather-resistant topcoat. The coating was applied to boards by spraying or brushing, and its performance was tested after curing at room temperature for 7 days. See Table 3 for the results.

[0037] Example 5: 60% of the epoxy-siloxane modified acrylic resin prepared in Example 3 was mixed with 20% chrome yellow, 10% barium sulfate, 9.4% xylene solvent, 0.5% dispersant, and 0.1% defoamer until homogeneous. The mixture was dispersed, ground, and then filtered and packaged to obtain the finished epoxy-siloxane modified acrylic weather-resistant topcoat. The coating was applied to boards by spraying or brushing, and its performance was tested after curing at room temperature for 7 days. The results are shown in Table 3.

[0038] Table 3 Performance Indicators of Epoxy-Siloxane Modified Acrylic Paint

[0039]

Claims

1. A high-performance epoxy-siloxane modified acrylic resin, characterized in that: The resin is made from the following components in parts by weight: 30-80 parts of acrylate monomers; Vinyltriisopropoxysilane 1-10 parts; Initiator 0.1-10 parts; 1-10 parts of epoxy-based siloxane; Catalyst 0.05-1 part; Solvent 1-30 parts; The acrylate monomers are styrene, methyl methacrylate, butyl acrylate and acrylic acid in a mass ratio of 5~8:20~30:10~18:0.5~1; The epoxy siloxane is β-(3,4-epoxycyclohexyl)ethyltriethoxysilane or γ-glycidyl etherpropyltrimethoxysilane in a mass ratio of 1~2.5:0.5~1.

2. The method includes the following steps: Step 1: Nitrogen gas is introduced into the reaction flask, and part of the solvent of the components is added into the reaction flask. The mixture is heated and refluxed to remove water. Then the temperature is lowered to 120-130℃, and the mixture of acrylate monomers and part of the initiator is slowly and evenly added. The reaction is maintained at this temperature for 1-3 hours. Step 2: Mix vinyltriisopropoxysilane with the remaining solvent and initiator evenly, and slowly and evenly add it to the reaction flask at a temperature of 120-130℃. After the addition is complete, continue to keep the temperature for 1-3 hours. Add the epoxy siloxane and catalyst to the reaction flask at the same temperature, and continue to keep the temperature for the reaction until the acid value is <5mgKOH / g and the reaction is completed. The epoxy siloxane modified acrylic resin can then be obtained.

2. The epoxy-siloxane modified acrylic resin according to claim 1, characterized in that: The resin is made from 36-55 parts of acrylate monomers, 2-6 parts of vinyltriisopropoxysilane, 1.5-2.5 parts of initiator, 1-5 parts of epoxysiloxane, 0.08-0.2 parts of catalyst and 20-25 parts of solvent.

3. The epoxy siloxane modified acrylic resin according to claim 1 or 2, characterized in that: the initiator is selected from one or more of di-tert-butyl peroxide and dicumyl peroxide.

4. The epoxysiloxane modified acrylic resin according to claim 1 or 2, wherein the catalyst is selected from one or more of triethylamine and triethanolamine.

5. The epoxysiloxane modified acrylic resin according to claim 4, wherein the catalyst is triethylamine and triethanolamine in a mass ratio of 0.03~0.06:0.07~0.

2.

6. A weather-resistant topcoat, characterized in that, The composition of this paint is as follows: 35-70 parts of the epoxy siloxane modified acrylic resin according to claim 1; 10-35 parts pigment; Additives: 0.1-3 parts; Solvent 5-15 parts; The pigment is selected from one or more of titanium dioxide, barium sulfate, iron oxide series, aluminum powder, and zinc oxide; the additive is selected from at least one of pigment wetting and dispersing agents, leveling agents, UV stabilizers, and UV absorbers; and the solvent is xylene.

7. The weather-resistant topcoat according to claim 6, characterized in that: The epoxy siloxane modified acrylic resin of claim 1 comprises 40-60 parts, pigment comprises 15-30 parts, additive comprises 0.1-1 parts, and solvent comprises 8-12 parts.

8. A method for preparing the weather-resistant topcoat according to claim 6, characterized in that: The epoxy siloxane modified acrylic resin is mixed evenly with the required pigments, fillers, additives, and solvents, dispersed, ground to a fineness of less than 20 micrometers, filtered, and packaged to obtain the finished weather-resistant topcoat.

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