Acrylic acid modified organic silicon polymer, solventless coating and preparation method of acrylic acid modified organic silicon polymer

Abstract

The invention relates to the technical field of modified organic silicon coatings, and discloses an acrylic acid modified organic silicon polymer, a solventless coating and a preparation method thereof.The acrylic acid modified organic silicon polymer is prepared from, by mass, 300 parts of polysiloxane, 100 parts of acrylic acid monomers and 1-2 parts of initiator; the polysiloxane is prepared by mixing alpha, omega-hydroxyl-terminated polymethylsiloxane and alpha, omega-hydroxyl-terminated poly (methyl-methyl vinyl) siloxane according to a mass ratio of (8 to 9): (1 to 2). The coating containing the organic silicon polymer is prepared from the following components in parts by mass: 260 parts of acrylic acid modified organic silicon polymer, 40 to 60 parts of alpha, omega-terminated methoxy polydimethylsiloxane, 5 to 10 parts of fumed silica, 15 to 25 parts of talcum powder, 40 parts of pigment paste, 25 to 30 parts of cross-linking agent, 10 to 20 parts of chain extender, 2.5 to 5 parts of A type coupling agent, 2.5 to 5 parts of B type coupling agent and 0.2 to 0.5 part of catalyst. The coating has the advantages of being environmentally friendly, high in strength, low in viscosity and suitable in surface drying time; the viscosity is below 1200 mpa.s, the tensile property of a corresponding coating is not lower than 3.8 MPa, and the surface drying time is within 45 min.

Description

Technical Field

[0001] The invention relates to the technical field of modified organic silicon coatings, and in particular to an acrylic acid modified organic silicon polymer, a solvent-free coating and a preparation method thereof. Background Art

[0002] Silicone coatings have the advantages of weather resistance, UV resistance, high and low temperature resistance, water resistance, and good elasticity. They have good application prospects in the fields of outdoor cement and metal protection, anti-corrosion, etc. However, silicone coatings also have relatively low mechanical strength and low adhesion to substrates, which restrict their application and development in the field of coatings. Modifying, reinforcing and thickening silicone with acrylic polymers to prepare acrylic modified silicone coatings is a better technical route. Compared with the conventional addition of solid reinforcing fillers, it can effectively prevent excessive thixotropy and ensure the construction performance of the coating. However, the addition of acrylic polymers will also cause a significant increase in the viscosity of the system, which can be adjusted by increasing the amount of solvent in conventional solvent-based coating systems.

[0003] In recent years, restrictions on the amount of volatile organic compounds (VOCs) in coatings have become increasingly stringent at home and abroad. Organic solvents in coatings are the largest source of VOCs. Therefore, solvent-free coatings have gradually been favored by the industry due to their outstanding environmental protection characteristics. However, the characteristic of solvent-free coatings that they do not use solvents for dilution often makes it difficult to solve the problem of high viscosity of the corresponding coatings, and the addition of acrylic polymers will further increase the viscosity of silicone coatings. Therefore, solvent-free acrylic modified silicone coatings often have the problem of high viscosity affecting construction. To prepare acrylic modified silicone coatings with low viscosity, it is necessary to use low-molecular-weight low-viscosity prepolymers as the main film-forming material. However, due to its small molecular weight, even with the reinforcement of acrylic polymers or other raw materials, the strength of the coating after drying and film formation is still not high. Therefore, there is a performance contradiction between high strength and low viscosity in this coating system that is difficult to take into account. In addition, since there is no solvent volatilization after coating, solvent-free acrylic modified silicone coatings only rely on system cross-linking, curing and drying to form a film. It often has a long surface drying time and is difficult to meet the construction requirements in many application environments. Summary of the invention

[0004] The present invention aims to provide an acrylic modified silicone polymer, a solvent-free coating and a preparation method thereof, aiming to obtain a solvent-free acrylic modified silicone coating product which is green, environmentally friendly, has high strength, low viscosity and suitable surface drying time.

[0005] To achieve the above-mentioned purpose, the present invention adopts the following technical scheme: an acrylic modified silicone polymer, which comprises, by weight, 300 parts of polysiloxane, 100 parts of acrylic monomer, and 1 to 2 parts of initiator; the polysiloxane is a mixture of α, ω-terminated hydroxyl polymethylsiloxane and α, ω-terminated hydroxyl poly(methyl-methylvinyl)siloxane in a mass ratio of (8 to 9):(1 to 2).

[0006] Preferably, as an improvement, the α,ω-terminated hydroxyl polymethylsiloxane is a mixture of α,ω-dihydroxy polydimethylsiloxane with a viscosity of 100 mPa.s and α,ω-dihydroxy polydimethylsiloxane with a viscosity of 500 mPa.s in a mass ratio of 1:1; the viscosity of the α,ω-terminated hydroxyl poly(methyl-methylvinyl)siloxane is 100 mPa.s, and the mass fraction of vinyl is 0.03%.

[0007] Preferably, as an improvement, the acrylic monomer includes at least one of methyl acrylate, n-butyl acrylate, isobutyl acrylate, tert-butyl acrylate, methyl methacrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate, cyclohexyl methacrylate, isooctyl acrylate, isobornyl acrylate, styrene, and acrylonitrile; and the initiator includes at least one of azobisisobutyronitrile, azobisisoheptylnitrile, dibenzoyl peroxide, dodecyl peroxide, and tert-butyl peroxypentanoate.

[0008] Preferably, as an improvement, a method for preparing an acrylic acid-modified silicone polymer comprises the following steps:

[0009] Step 1, stirring and mixing α,ω-terminated hydroxyl polymethylsiloxane and α,ω-terminated hydroxyl poly(methyl-methylvinyl)siloxane in a reactor;

[0010] Step 2: Heat the system to 65-100°C and fill with N2 for protection;

[0011] Step 3, adding acrylic acid monomers into the reaction system at a uniform speed for 200 to 400 minutes, and the reaction time from the start of monomer addition lasts for 300 to 600 minutes;

[0012] Step 4: After step 3, add the initiator into the system in three batches. Add the first batch of initiator at the beginning of monomer addition, and add the next batch of initiator every 100 to 200 minutes. After the reaction is completed, cool the material to obtain an acrylic modified silicone polymer.

[0013] Preferably, as an improvement, a solvent-free coating containing an acrylic modified silicone polymer comprises, by mass, 260 parts of an acrylic modified silicone polymer, 40 to 60 parts of α, ω-terminated methoxy polydimethylsiloxane, 40 to 60 parts of active nano-calcium carbonate, 5 to 10 parts of fumed silica, 15 to 25 parts of talc, 40 parts of pigment slurry, 25 to 30 parts of a cross-linking agent, 10 to 20 parts of a chain extender, 2.5 to 5 parts of a type A coupling agent, 2.5 to 5 parts of a type B coupling agent, and 0.2 to 0.5 parts of a catalyst.

[0014] Preferably, as an improvement, the viscosity of α,ω-terminated methoxy polydimethylsiloxane is 300 mPa.s; the D50 of active nano calcium carbonate is 600 nm; the specific surface area of ​​fumed silica is 200 m 2 / g; the fineness of talcum powder is 800 mesh; the pigment slurry is a mixture of titanium white pigment slurry and carbon black slurry.

[0015] Preferably, as an improvement, the mass ratio of titanium white pigment slurry to carbon black slurry in the pigment slurry is 10:0.5.

[0016] Preferably, as an improvement, the crosslinking agent is at least one of tetrabutyl ketone oxime silane, methyl tributyl ketone oxime silane, methyl trimethoxy silane, methyl triethoxy silane, vinyl triethoxy silane, methacryloxypropyl trimethoxy silane, and ethyl orthosilicate; the chain extender is at least one of dimethyl dibutyl ketone oxime silane, methyl vinyl dibutyl ketone oxime silane, dimethyl dimethoxy silane, methyl vinyl dimethoxy silane, and methyl vinyl diethoxy silane.

[0017] Preferably, as an improvement, the Class A coupling agent is at least one of glycidyloxypropyl trimethoxysilane, methacryloxypropyl trimethoxysilane, methacryloxypropyl triethoxysilane, and diethylaminomethyl triethoxysilane; the Class B coupling agent is an aminosilane coupling agent, specifically at least one of aminopropyl trimethoxysilane, aminopropyl triethoxysilane, aminopropyl methyl diethoxysilane, aminopropyl methyl triethoxysilane, and N-phenyl-3-aminopropyl trimethoxysilane; and the catalyst is at least one of dibutyltin dilaurate, dioctyltin dilaurate, dibutyltin diacetate, and stannous octoate.

[0018] Preferably, as an improvement, a method for preparing a solvent-free coating containing an acrylic acid-modified silicone polymer is characterized by comprising the following steps:

[0019] S1, mixing acrylic acid modified silicone polymer, active nano calcium carbonate, fumed silica and talcum powder, stirring evenly, and then kneading under vacuum conditions to obtain a base material;

[0020] S2. Add α,ω-terminated methoxy polydimethylsiloxane to the base material under stirring at room temperature, then stir under vacuum, then add pigment slurry, chain extender and the first part of catalyst respectively, mix well and stir under vacuum; add cross-linking agent, non-amino coupling agent, amino coupling agent and remaining catalyst, mix well and stir under vacuum, and after stirring well, discharge and package.

[0021] The principle and advantage of this scheme are: In this technical scheme, in view of the problems existing in the existing technical routes, the present invention provides a type of technical route: using low-viscosity polysiloxane, including α, ω-terminated hydroxyl polydimethylsiloxane and α, ω-terminated hydroxyl poly(dimethyl-methylvinyl) siloxane as basic film-forming materials, after being modified by acrylic acid, the polysiloxane α, ω-terminated hydroxyl polydimethylsiloxane does not react with the acrylic monomer, and the vinyl side group of the α, ω-terminated hydroxyl poly(dimethyl-methylvinyl) siloxane is copolymerized with the acrylic monomer to finally form a high molecular interpenetrating network structure of polysiloxane and acrylate, and there is partial cross-linking, forming a relatively stable polymer composite system as a film-forming material for the coating. In the subsequent process of making the finished product, a chain extender is added to keep the viscosity of the coating low during construction. At the same time, when the coating is cured in the air, the short chains of the low-viscosity silicone polysiloxane are connected into long chains, which improves the strength and toughness of the final coating, and combines the reinforcement function of the acrylic polymer to obtain a high-strength coating; at the same time, low-viscosity α, ω-terminated methoxy polydimethylsiloxane and amino silane are added in the process of making the finished product. The terminal methoxy polysiloxane has an end group that can directly react and cure with moisture in the air, and its reaction activity is higher than that of conventional α, ω-terminated hydroxyl polydimethylsiloxane. The amino group in the aminosilane promotes the end group cross-linking and curing of α, ω-terminated hydroxyl polydimethylsiloxane and α, ω-terminated methoxy polydimethylsiloxane. Both can accelerate the curing speed of the coating.

[0022] Therefore, the technical solution mainly solves the following problems: (1) the performance contradiction between high strength and low viscosity of solvent-free acrylic modified silicone coating; (2) the problem that the surface drying time of solvent-free acrylic modified silicone coating is too long and is not conducive to construction. Thus, a solvent-free acrylic modified silicone coating with high strength, low viscosity and suitable surface drying time is prepared.

[0023] In summary, this technical solution has the following beneficial effects:

[0024] 1. In the present technical scheme, the prepared acrylic modified silicone coating product has low viscosity based on the low viscosity polysiloxane film former, which ensures the workability. The polysiloxane molecular chain is extended by the chain extender during the later curing of the coating, and the acrylic polymer is further reinforced to obtain a high-strength coating, thereby achieving the performance advantages of both high strength of the coating and low viscosity of the coating.

[0025] 2. In this technical solution, low-viscosity α, ω-terminated methoxy polydimethylsiloxane and amino silane are added during the production of the finished product, both of which accelerate the curing speed of the coating and improve the problem of slow surface drying of general acrylic modified silicone coatings that affects construction. DETAILED DESCRIPTION

[0026] The following is further described in detail through specific implementations, but the implementation of the present invention is not limited thereto. Unless otherwise specified, the technical means used in the following implementations are conventional means well known to those skilled in the art; the experimental methods used are all conventional methods; the materials, reagents, etc. used can all be obtained from commercial channels.

[0027] Program Overview:

[0028] An acrylic acid-modified organic silicon polymer comprises, by weight, 300 parts of polysiloxane, 100 parts of acrylic acid monomers and 1 to 2 parts of initiator.

[0029] The polysiloxane is a mixture of α,ω-terminated hydroxyl polymethylsiloxane and α,ω-terminated hydroxyl poly(methyl-methylvinyl)siloxane in a mass ratio of (8-9):(1-2).

[0030] The α,ω-terminated hydroxyl polymethylsiloxane is prepared by mixing α,ω-dihydroxy polydimethylsiloxane with a viscosity of 100 mPa.s and α,ω-dihydroxy polydimethylsiloxane with a viscosity of 500 mPa.s in a mass ratio of 1:1.

[0031] The viscosity of the α,ω-hydroxy-terminated poly(methyl-methylvinyl)siloxane is 100 mPa.s, and the mass fraction of the vinyl group is 0.03%.

[0032] The acrylic monomer includes at least one of methyl acrylate, n-butyl acrylate, isobutyl acrylate, tert-butyl acrylate, methyl methacrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate, cyclohexyl methacrylate, isooctyl acrylate, isobornyl acrylate, styrene and acrylonitrile.

[0033] The initiator includes at least one of azobisisobutyronitrile, azobisisoheptanenitrile, dibenzoyl peroxide, dodecyl peroxide, and tert-butyl peroxyvalerate.

[0034] A method for preparing an acrylic acid-modified organosilicon polymer comprises the following steps:

[0035] Step 1: Stir and mix α,ω-terminated hydroxyl-polymethylsiloxane and α,ω-terminated hydroxyl-poly(methyl-methylvinyl)siloxane in a reactor.

[0036] Step 2: Heat the system to 65-100°C and fill with N2 for protection.

[0037] Step 3: Add acrylic monomer (if two or more monomers are included, mix them in advance) to the reaction system at a uniform speed for 200 to 400 minutes. The reaction time from the start of the addition of the monomers is 300 to 600 minutes.

[0038] Step 4: After step 3, add the initiator into the system in three batches. Add the first batch of initiator at the beginning of monomer addition, and add the next batch of initiator every 100 to 200 minutes. After the reaction is completed, cool the material to obtain an acrylic modified silicone polymer.

[0039] A solvent-free coating containing an acrylic modified silicone polymer comprises, by mass, 260 parts of an acrylic modified silicone polymer, 40-60 parts of α,ω-terminated methoxy polydimethylsiloxane, 40-60 parts of active nano calcium carbonate, 5-10 parts of fumed silica, 15-25 parts of talc, 40 parts of pigment slurry, 25-30 parts of a crosslinking agent, 10-20 parts of a chain extender, 2.5-5 parts of a type A coupling agent, 2.5-5 parts of a type B coupling agent and 0.2-0.5 parts of a catalyst.

[0040] Among them, the viscosity of α,ω-terminated methoxy polydimethylsiloxane is 300mPa.s; the D50 of active nano calcium carbonate is 600nm; the specific surface area of ​​fumed silica is 200m 2 / g; the fineness of the stone powder is 800 mesh; the pigment slurry is a mixture of titanium dioxide pigment slurry and carbon black slurry in a mass ratio of 10:0.5.

[0041] The crosslinking agent is at least one of tetrabutyl ketoxime silane, methyl tributyketoxime silane, methyl trimethoxy silane, methyl triethoxy silane, vinyl triethoxy silane, methacryloxypropyl trimethoxy silane and ethyl orthosilicate.

[0042] The chain extender is at least one of dimethyl dibutyl ketoxime silane, methyl vinyl dibutyl ketoxime silane, dimethyl dimethoxy silane, methyl vinyl dimethoxy silane and methyl vinyl diethoxy silane.

[0043] The type A coupling agent is at least one of glycidyloxypropyl trimethoxysilane, methacryloxypropyl trimethoxysilane, methacryloxypropyl triethoxysilane, and diethylaminomethyl triethoxysilane.

[0044] The type B coupling agent is an aminosilane coupling agent, specifically at least one of aminopropyltrimethoxysilane, aminopropyltriethoxysilane, aminopropylmethyldiethoxysilane, aminopropylmethyltriethoxysilane, and N-phenyl-3-aminopropyltrimethoxysilane.

[0045] The catalyst is at least one of dibutyltin dilaurate, dioctyltin dilaurate, dibutyltin diacetate and stannous octoate.

[0046] A method for preparing a solvent-free coating containing acrylic acid-modified silicone polymer comprises the following steps:

[0047] S1. Mix and stir acrylic modified silicone polymer, fumed silica and talcum powder evenly, and then knead them at 130°C and 0.09Mpa vacuum for 3 hours to obtain a base material;

[0048] S2. Add α,ω-terminated methoxy polydimethylsiloxane to the base material under stirring at room temperature, then vacuum and stir for 5 minutes. Then add pigment slurry, chain extender and the first part of catalyst (accounting for 1 / 10 of the total amount) respectively, mix well and vacuum and stir for 15 minutes; add cross-linking agent, non-amino coupling agent, amino coupling agent and remaining catalyst, mix well and vacuum and stir for 25 minutes. After stirring well, discharge and package.

[0049] Example 1

[0050] A method for preparing an acrylic acid-modified organosilicon polymer comprises the following steps:

[0051] Step 1, putting 100mPa.s of α,ω-dihydroxy polydimethylsiloxane polysiloxane including 84.8g of α,ω-terminated hydroxyl polymethylsiloxane, 84.8g of 500mPa.s of α,ω-dihydroxy polydimethylsiloxane polysiloxane, and 42.4g of 100mPa.s of α,ω-terminated hydroxyl poly(methyl-methylvinyl) siloxane into a reactor and stirring and mixing evenly;

[0052] Step 2: Heat the system to 90°C and fill with N2 for protection.

[0053] Step 3: Mix 62 g of methyl methacrylate and 8.5 g of n-butyl acrylate, stir, and add into the reaction system at a uniform speed for 280 min.

[0054] Step 4: Add 0.9 g of initiator azobisisobutyronitrile into the system in three batches. Add the first batch of initiator 0.3 g of azobisisobutyronitrile at the beginning of adding the monomers, react for 140 min, add the second batch of 0.3 g of azobisisobutyronitrile, and react for 140 min. Add the second batch of 0.3 g of azobisisobutyronitrile; continue the reaction for 140 min, and then cool and discharge.

[0055] A solvent-free coating containing acrylic acid-modified organosilicon polymer comprises the following steps:

[0056] S1, 260g of the acrylic acid-modified silicone polymer prepared in the above step, 50 parts of active nano-calcium carbonate, 5g of fumed silica, and 20g of talcum powder were mixed and stirred evenly, and then kneaded at 130°C and 0.09Mpa vacuum for 3 hours to obtain a base material;

[0057] S2. At room temperature, add 40 g of α, ω-terminated methoxypolydimethylsiloxane to the base material while stirring, and then vacuum stir for 5 minutes. Then, add 40 g of pigment slurry, 15 g of dimethyl dibutyl ketone oxime silane and 0.03 g of dibutyl tin dilaurate, mix well and vacuum stir for 15 minutes. Add 25 g of methyl tributy ketone oxime silane, 5 g of methacryloyloxypropyl trimethoxy silane, 5 g of aminopropyl triethoxy silane and 0.27 g of dibutyl tin dilaurate, mix well and vacuum stir for 25 minutes. After stirring well, discharge and package.

[0058] Example 2

[0059] A method for preparing an acrylic acid-modified organosilicon polymer comprises the following steps:

[0060] Step 1, put 100mPa.s of α,ω-dihydroxy polydimethylsiloxane polysiloxane including 95.4g of α,ω-terminated hydroxyl polymethylsiloxane, 95.4g of 500mPa.s of α,ω-dihydroxy polydimethylsiloxane polysiloxane, and 21.2g of 100mPa.s of α,ω-terminated hydroxyl poly(methyl-methylvinyl) siloxane into a reactor and stir and mix evenly;

[0061] Step 2: Heat the system to 80°C and fill with N2 for protection.

[0062] Step 3: Mix 56.5 g of cyclohexyl methacrylate and 14 g of isooctyl acrylate, stir, and add into the reaction system at a uniform speed for 340 min.

[0063] Step 4: Add 0.75 g of initiator dibenzoyl peroxide into the system in three batches, add the first batch of initiator 0.25 g of azobisisobutyronitrile at the beginning of adding the monomer, react for 170 min, add the second batch of 0.25 g of azobisisobutyronitrile, react for 170 min, add the second batch of 0.3 g of azobisisobutyronitrile; continue the reaction for 170 min, and cool and discharge.

[0064] A method for preparing a solvent-free coating containing acrylic acid-modified silicone polymer comprises the following steps:

[0065] S1, 260g of the acrylic acid-modified silicone polymer prepared in the above step, 60 parts of active nano-calcium carbonate, 7.5g of fumed silica, and 15g of talcum powder were mixed and stirred evenly, and then kneaded at 130°C and 0.09Mpa vacuum for 3 hours to obtain a base material;

[0066] S2. At room temperature, add 50 g of α, ω-terminated methoxypolydimethylsiloxane to the base material while stirring, and then vacuum stir for 5 minutes. Then add 40 g of pigment slurry, 11 g of methyl vinyl dibutyl ketone oxime silane and 0.04 g of dibutyl tin dilaurate, mix well and vacuum stir for 15 minutes; add 10 g of tetrabutyl ketone oxime silane, 18 g of methyl triethoxy silane, 2.5 g of glycidyl ether oxypropyl trimethoxy silane, 3 g of aminopropyl triethoxy silane and 0.36 g of dioctyltin dilaurate, mix well and vacuum stir for 25 minutes. After stirring well, discharge and package.

[0067] Example 3

[0068] A method for preparing an acrylic acid-modified organosilicon polymer comprises the following steps:

[0069] Step 1, put 100mPa.s of α,ω-dihydroxy polydimethylsiloxane polysiloxane including 90.1g of α,ω-terminated hydroxyl polymethylsiloxane, 90.1g of 500mPa.s of α,ω-dihydroxy polydimethylsiloxane polysiloxane, and 31.8g of 100mPa.s of α,ω-terminated hydroxyl poly(methyl-methylvinyl) siloxane into a reactor and stir and mix evenly;

[0070] Step 2: Heat the system to 70°C and fill with N2 for protection.

[0071] Step 3: Mix 50 g of styrene and 20.5 g of isooctyl acrylate, stir, and add into the reaction system at a uniform speed for 400 min.

[0072] Step 4: 1.35 g of initiator dibenzoyl peroxide is added to the system in three batches. When the monomer is added, the first batch of initiator 0.45 g of azobisisoheptanenitrile is added, and the reaction is continued for 200 min. Then, the second batch of 0.45 g of azobisisobutyronitrile is added. After the reaction is continued for 200 min, the material is cooled and discharged.

[0073] A method for preparing a solvent-free coating containing acrylic acid-modified silicone polymer comprises the following steps:

[0074] S1, 260g of the acrylic acid-modified silicone polymer prepared in the above step, 40 parts of active nano-calcium carbonate, 10g of fumed silica, and 25g of talcum powder were mixed and stirred evenly, and then kneaded at 130°C and 0.09Mpa vacuum for 3 hours to obtain a base material;

[0075] S2. At room temperature, add 60 g of α, ω-terminated methoxypolydimethylsiloxane to the base material under stirring, and stir in a vacuum for 5 minutes. Then, add 40 g of pigment slurry, 12 g of methylvinyldimethoxysilane, 12 g of methylvinyldiethoxysilane and 0.05 g of stannous octoate, mix well and stir in a vacuum for 15 minutes. Add 20 g of methyltrimethoxysilane, 10 g of ethyl orthosilicate, 4 g of methacryloyloxypropyltriethoxysilane, 4 g of N-phenyl-3-aminopropyltrimethoxysilane and 0.45 g of stannous octoate, mix well and stir in a vacuum for 25 minutes. After stirring well, discharge and package.

[0076] Comparative Example 1

[0077] The chain extender dimethyl dibutyl ketone oxime silane in the finished coating formulation of Example 1 was removed, and the other formulations and steps were the same.

[0078] Comparative Example 2

[0079] The polysiloxane raw materials used in the preparation process of the acrylic modified silicone polymer in Example 1 were replaced with 84.8 g of 1000 mPa.s α, ω-dihydroxy polydimethylsiloxane, 84.8 g of 10000 mPa.s α, ω-terminated hydroxyl polymethylsiloxane, and 42.4 g of 1000 mPa.s α, ω-terminated hydroxyl poly(methyl-methylvinyl) siloxane. At the same time, the chain extender dimethyl dibutyl ketoxime silane in the finished coating formula was removed, and the other formulas and steps were the same.

[0080] Comparative Example 3

[0081] The α,ω-terminated methoxy polydimethylsiloxane in the finished solvent-free coating formula containing acrylic modified silicone polymer in Example 1 was replaced with α,ω-terminated hydroxyl polydimethylsiloxane of the same viscosity, and the other formulas and steps were the same.

[0082] Comparative Example 4

[0083] The aminopropyl triethoxysilane in the finished solvent-free coating formula containing acrylic modified silicone polymer in Example 1 was replaced with methacryloxypropyl triethoxysilane, and the other formulas and steps were the same.

[0084] Comparative Example 5

[0085] The α,ω-terminated hydroxyl poly(methyl-methylvinyl)siloxane in Example 1 was replaced with an α,ω-terminated hydroxyl polydimethylsiloxane of equal mass and viscosity, and the other formulas and steps were the same.

[0086] Experimental Example Performance Test

[0087] The performance test indexes and test methods for the solvent-free coating containing acrylic acid-modified silicone polymer in the embodiment of the present invention are as follows:

[0088] The state in the container, construction performance, surface drying time, salt spray resistance, salt water resistance, water resistance, acid resistance, artificial aging resistance and temperature change resistance are tested in accordance with the standard of JG / T 224-2007 Anti-corrosion coatings for steel structures in construction.

[0089] The viscosity was tested using a rotational viscometer under standard conditions, namely, temperature (23±2)°C and relative humidity (50±5)%.

[0090] The tensile strength is tested in accordance with JG / T 512-2017 General Technical Requirements for Building Exterior Wall Paints.

[0091] The test results of the coating properties of the embodiments and comparative examples are shown in Table 1.

[0092] Table 1 Performance test results of embodiments and comparative examples

[0093]

[0094]

[0095] From the data in Table 1, it can be seen that compared with Example 1, after the chain extender is removed from the coating formula of Comparative Example 1, the tensile strength is lower. This is probably because there is no chain extender in the formula. Therefore, when the coating is cured in the air, the short chain of the low-viscosity silicone polysiloxane will not grow into a long chain, and the silicone molecular chain is too short, resulting in a low strength of the coating; in Comparative Example 2, after the chain extender is removed from the coating formula of Example 1, the low-viscosity polysiloxane in the preparation process of the acrylic modified silicone polymer is replaced with a high-viscosity polysiloxane. The tensile strength of the coating is at the same level as that of Example 1, but its viscosity is very large, which has a great impact on the coating construction. Therefore, it can be seen that the use of low-viscosity polysiloxane and chain extender in the present invention can effectively solve the performance contradiction between low viscosity and high strength of solvent-free acrylic modified silicone coating. At the same time, compared with Example 1, the surface drying time of Comparative Examples 3 and 4 is significantly increased, indicating that the use of α,ω-terminated methoxy polydimethylsiloxane or aminosilane has significantly improved the problem of too long surface drying time of solvent-free acrylic modified silicone coating affecting construction. The strength of Comparative Example 5 is lower than that of Example 1, indicating that during the preparation of the acrylic modified silicone polymer, the cross-linked structure formed by the reaction of α,ω-terminated hydroxyl poly(dimethyl-methylvinyl)siloxane with the acrylic monomer is beneficial to improving the strength of the coating.

[0096] The above is only an embodiment of the present invention, and the common knowledge such as the known specific technical solutions and / or characteristics in the solution is not described in detail here. It should be pointed out that for those skilled in the art, without departing from the technical solution of the present invention, several modifications and improvements can be made, which should also be regarded as the protection scope of the present invention, and these will not affect the effect of the implementation of the present invention and the practicality of the patent. The scope of protection required by this application shall be based on the content of its claims, and the specific implementation methods and other records in the specification can be used to interpret the content of the claims.

Claims

1. An acrylic acid-modified silicone polymer, characterized in that: The invention comprises 300 parts of polysiloxane, 100 parts of acrylic monomer and 1 to 2 parts of initiator in parts by mass; the polysiloxane is a mixture of α, ω-terminated hydroxyl polymethylsiloxane and α, ω-terminated hydroxyl poly(methyl-methylvinyl)siloxane in a mass ratio of (8 to 9):(1 to 2).

2. The acrylic acid-modified silicone polymer according to claim 1, characterized in that: The α,ω-terminated hydroxyl polymethylsiloxane is prepared by mixing α,ω-dihydroxy polydimethylsiloxane with a viscosity of 100 mPa.s and α,ω-dihydroxy polydimethylsiloxane with a viscosity of 500 mPa.s in a mass ratio of 1:1; the viscosity of the α,ω-terminated hydroxyl poly(methyl-methylvinyl)siloxane is 100 mPa.s, and the mass fraction of vinyl is 0.03%.

3. An acrylic acid-modified silicone polymer according to claim 2, characterized in that: The acrylic monomer includes at least one of methyl acrylate, n-butyl acrylate, isobutyl acrylate, tert-butyl acrylate, methyl methacrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate, cyclohexyl methacrylate, isooctyl acrylate, isobornyl acrylate, styrene, and acrylonitrile; the initiator includes at least one of azobisisobutyronitrile, azobisisoheptylnitrile, dibenzoyl peroxide, dodecyl peroxide, and tert-butyl peroxypentylate.

4. The method for preparing an acrylic acid-modified silicone polymer according to any one of claims 1 to 3, characterized in that: The steps include: Step 1, stirring and mixing α,ω-terminated hydroxyl-polymethylsiloxane and α,ω-terminated hydroxyl-poly(methyl-methylvinyl)siloxane in a reactor; Step 2: Heat the system to 65-100°C and fill with N2 for protection; Step 3, adding acrylic acid monomers into the reaction system at a uniform speed for 200 to 400 minutes, and the reaction time from the start of monomer addition lasts for 300 to 600 minutes; Step 4: After step 3, add the initiator into the system in three batches. Add the first batch of initiator at the beginning of monomer addition, and add the next batch of initiator every 100 to 200 minutes. After the reaction is completed, cool the material to obtain an acrylic modified silicone polymer.

5. A solvent-free coating containing the acrylic modified silicone polymer according to any one of claims 1 to 3, characterized in that: Calculated by mass, it includes 260 parts of acrylic modified silicone polymer, 40-60 parts of α,ω-terminated methoxy polydimethylsiloxane, 40-60 parts of active nano calcium carbonate, 5-10 parts of fumed silica, 15-25 parts of talc, 40 parts of pigment slurry, 25-30 parts of cross-linking agent, 10-20 parts of chain extender, 2.5-5 parts of type A coupling agent, 2.5-5 parts of type B coupling agent and 0.2-0.5 parts of catalyst.

6. The solvent-free coating containing acrylic acid-modified silicone polymer according to claim 5, characterized in that: The viscosity of the α,ω-terminated methoxy polydimethylsiloxane is 300 mPa.s; the active nano calcium carbonate D50 is 600 nm; the specific surface area of ​​the fumed silica is 200 m 2 / g; the fineness of talcum powder is 800 mesh; the pigment slurry is a mixture of titanium white pigment slurry and carbon black slurry.

7. The solvent-free coating containing acrylic acid-modified silicone polymer according to claim 6, characterized in that: The mass ratio of titanium white pigment slurry to carbon black slurry in the pigment slurry is 10:0.

5.

8. The solvent-free coating containing acrylic acid-modified silicone polymer according to claim 7, characterized in that: The crosslinking agent is at least one of tetrabutyl ketone oxime silane, methyl tributyl ketone oxime silane, methyl trimethoxy silane, methyl triethoxy silane, vinyl triethoxy silane, methacryloxypropyl trimethoxy silane, and ethyl orthosilicate; the chain extender is at least one of dimethyl dibutyl ketone oxime silane, methyl vinyl dibutyl ketone oxime silane, dimethyl dimethoxy silane, methyl vinyl dimethoxy silane, and methyl vinyl diethoxy silane.

9. The solvent-free coating containing acrylic acid-modified silicone polymer according to claim 8, characterized in that: The Class A coupling agent is at least one of glycidyloxypropyl trimethoxysilane, methacryloxypropyl trimethoxysilane, methacryloxypropyl triethoxysilane, and diethylaminomethyl triethoxysilane; the Class B coupling agent is an aminosilane coupling agent, specifically at least one of aminopropyl trimethoxysilane, aminopropyl triethoxysilane, aminopropyl methyl diethoxysilane, aminopropyl methyl triethoxysilane, and N-phenyl-3-aminopropyl trimethoxysilane; the catalyst is at least one of dibutyltin dilaurate, dioctyltin dilaurate, dibutyltin diacetate, and stannous octoate.

10. The method for preparing a solvent-free coating containing acrylic acid-modified silicone polymer according to claim 9, characterized in that: The steps include: S1, mixing acrylic acid modified silicone polymer, active nano calcium carbonate, fumed silica and talcum powder, stirring evenly, and then kneading under vacuum conditions to obtain a base material; S2. Add α,ω-terminated methoxy polydimethylsiloxane to the base material under stirring at room temperature, then stir under vacuum, then add pigment slurry, chain extender and the first part of catalyst respectively, mix well and stir under vacuum; add cross-linking agent, non-amino coupling agent, amino coupling agent and remaining catalyst, mix well and stir under vacuum, and after stirring well, discharge and package.

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