Preparation method of super-stable brush-like silicone microsphere coated modified pigment

Abstract

The application discloses a preparation method of super-stable brush-shaped silicone microsphere coated modified pigments, which comprises the following steps: weighing raw materials and preparing a pre-emulsified mixed solution, preparing organic silicone resin coated pigments, and preparing brush-shaped silicone microsphere coated modified pigments; the method is simple and easy to operate; by selecting or combining grafting monomers, the brush-shaped composite pigment particles can be endowed with diversified functions, such as antibacterial property, anti-specific adsorption and the like; the rich hydrophilic groups in the grafted polymer chain can further improve the stability of the composite pigment particles; the organic silicone resin layer with various excellent properties, such as UV radiation resistance and corrosion resistance, can also improve the performance of the coated pigments in specific application systems; and the brush-shaped composite pigment particles prepared by the method have wide application prospects in the field of high-quality and functional coating and other industrial products.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of nanocomposites, and particularly relates to a preparation method of super-stable brush-shaped silicone microsphere coated modified pigments. BACKGROUND

[0002] Pigments are often added and dispersed in various application systems such as paints, plastics, rubbers and the like as colorants. Compared with dyes, pigments have advantages such as more types, strong tinting strength, wide color spectrum, non-toxic or low toxicity and the like. However, with the gradual increase of requirements in various aspects such as consumer market and industry transformation and upgrading, the application performance of pigments in specific systems needs to be optimized and improved. Pigment modification technology can change the particle size and distribution, crystal form or surface polarity of pigments by physical or chemical means to achieve the purpose of changing and improving the performance of pigments. At present, the technologies for modifying pigments mainly include two categories: one is pigment coating technology in which pigment particles are coated inside microspheres through physical adsorption or chemical bond, and the other is surface modification technology in which the surface of pigment particles is treated.

[0003] Brush-shaped microspheres are nanoscale spherical polymer brushes with core-shell structure formed by connecting polymer chains to the surface of spherical cores at a high grafting density. Silicone has the characteristics of low surface tension, high and low temperature resistance, corrosion resistance and the like. Brush-shaped silicone microspheres have the advantages of high stability and easy functionalization when used for coating and modifying pigments. The grafted polymer chains can prevent the agglomeration and sedimentation of composite pigment particles through steric hindrance, electrostatic interaction and the like, which can further improve the stability of pigment particles. The grafted monomers forming the brush-shaped structure on the surface of composite pigment particles are abundant in sources, and can be selected or combined according to requirements to endow the coated pigments with various functions such as antibacterial and antifouling.

[0004] In the prior art, the research on coating and modifying pigments by using silicone mainly focuses on the following aspects:

[0005] (1) Using the excellent performance of silicone to improve resins such as polyurethane or acrylic to coat pigment particles;

[0006] (2) Using pure silicone resin to coat and modify pigments;

[0007] (3) Continuously modifying the surface of pigment particles coated by silicone, such as modifying a layer of silane coupling agent and then chemically bonding with other functional materials;

[0008] But because the organic silicon material is a low surface energy hydrophobic material, leading to the composite pigment particles after coating easy to occur agglomeration settlement, so that the composite pigment particles show the shortcomings of poor stability, and the traditional modified pigment coating process also has the problems of complex process, not easy to operate and low universality, the industry urgently needs to obtain the pigment modification preparation method which is simple to operate, has controllable uniform particle size, strong functionality and good universality, therefore, the application provides a preparation method of super stable brush-shaped organic silicon microsphere coated modified pigment to solve the problems in the prior art. SUMMARY

[0009] In view of the above problems, the purpose of the present application is to provide a preparation method of super stable brush-shaped organic silicon microsphere coated modified pigment to solve the problems of poor stability of composite pigment particles and complex process, not easy to operate and low universality in the prior art of organic silicon coated modified pigment.

[0010] In order to achieve the purpose of the present application, the present application is realized by the following technical scheme: a preparation method of super stable brush-shaped organic silicon microsphere coated modified pigment, comprising the following steps:

[0011] Step one: first, the pigment, the reaction monomer, the surfactant, the auxiliary stabilizer, the deionized water and the hydrolysis-condensation catalyst are weighed according to the mass ratio of 1:13:0.5-2.5:0.5:180-250:50 as raw materials for standby, and the raw materials except the hydrolysis-condensation catalyst are pre-emulsified by using an ultrasonic cell crusher;

[0012] Step two: the mixed solution after pre-emulsification is transferred to a three-necked flask and heated in an oil bath pot, and after heating to the preset temperature, the hydrolysis-condensation catalyst is added to the mixed solution at a uniform speed, and the composite pigment emulsion coated with organic silicon is prepared by miniemulsion polymerization;

[0013] Step three: the composite pigment emulsion (calculated according to the solid mass contained in the emulsion) and the initiator are weighed according to the mass ratio of 40:1 as raw materials for standby, and then the weighed composite pigment emulsion and initiator are mixed and the grafting monomer is added, and the brush-shaped composite pigment is prepared by surface direct initiation grafting polymerization, which is the brush-shaped organic silicon microsphere coated modified and functionalized pigment.

[0014] Further improvement lies in that in step one, the pigment is selected from one of phthalocyanine blue, prussian blue, phthalocyanine green, lead chrome green, iron oxide red or composite titanium red, and the reaction monomer is selected from one or more of methyltrimethoxysilane, phenyltrimethoxysilane, methylphenyldimethoxysilane or vinyltrimethoxysilane.

[0015] Further improvement lies in that the surface active agent in step one is selected from one of sodium dodecyl sulfate, cetyltrimethylammonium bromide or alkylphenol polyoxyethylene ether, and the co-stabilizer is selected from one of n-hexadecane or cyclohexane.

[0016] Further improvement lies in that the hydrolysis-condensation catalyst in step one is selected from one of hydrochloric acid aqueous solution or ammonia water, wherein the concentration of the hydrochloric acid aqueous solution is 1.0 wt%, and the concentration of the ammonia water is 3.0 wt%.

[0017] Further improvement lies in that in step two, the oil bath pot is heated to 45-70℃, and then the hydrolysis-condensation catalyst is added dropwise, and the dropping speed of the hydrolysis-condensation catalyst is 0.3-1.0 mL / min.

[0018] Further improvement lies in that in step three, the initiator is a thermal initiator, and is specifically selected from one of potassium persulfate or dibenzoyl peroxide, and the specific steps for preparing the brush-shaped composite pigment by using the thermal initiator are as follows: the weighed composite pigment emulsion and potassium persulfate are poured into a three-necked flask and mixed uniformly, then the three-necked flask is placed in an oil bath pot, heated to 70℃ under nitrogen protection, and stabilized for 10 min, 1.6-3.2 g of grafting monomer is added dropwise into the three-necked flask at a uniform speed, and the brush-shaped composite pigment is obtained by using a surface direct thermal initiation grafting polymerization method.

[0019] Further improvement lies in that the grafting monomer is selected from one of acrylic monomer or hydroxyethyl acrylamide functional monomer, and the dropping speed of the grafting monomer is 0.3-1.0 mL / min.

[0020] Further improvement lies in that in step three, the initiator is a light initiator, and is specifically selected from one of benzophenone or azobisisobutyronitrile, and the specific steps for preparing the brush-shaped composite pigment by using the light initiator are as follows: the weighed composite pigment emulsion and benzophenone are poured into a photo reactor, 0.8-2.4 g of grafting monomer is added and mixed and stirred, then the mixed solution is irradiated under the protection of nitrogen by turning on an ultraviolet radiation lamp, and the brush-shaped composite pigment is obtained by using a surface direct light initiation grafting polymerization method.

[0021] The beneficial effects of the present application are: the present application prepares the composite pigment of the pigment coated by the silicone resin through the miniemulsion polymerization method, then initiates the graft polymerization of the functional monomer under the initiation of the visible light / thermal initiator, obtains the brush-shaped composite pigment particles, and can control the particle size of the brush-shaped composite pigment particles by controlling the addition amount of the functional monomer, the whole preparation process is simple and easy to operate, the brush-shaped composite pigment particles can be endowed with diversified functions such as antibacterial property, anti-specific adsorption and the like by selecting or combining the grafting monomer, and the rich hydrophilic groups in the grafted polymer chain can further improve the stability of the composite pigment particles, the organic silicon resin layer with various excellent properties such as UV radiation resistance, corrosion resistance and the like can also improve the performance of the coated pigment in the specific application system, and the brush-shaped composite pigment particles prepared by the method have wide application prospects in the field of high-quality, functional coating and other industrial products. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 is a preparation method flowchart of the ultra-stable brush-shaped silicone microsphere coated modified pigment of the present application;

[0023] Figure 2 is a strength and hydrodynamic diameter distribution result schematic diagram of the composite pigment particles and the brush-shaped composite pigment particles in the embodiment of the present application;

[0024] Figure 3 is a storage stability comparison schematic diagram of the brush-shaped polyhydroxyethyl acrylamide composite pigment particles, the brush-shaped polyacrylic acid composite pigment particles and the composite pigment particles in the embodiment of the present application. DETAILED DESCRIPTION

[0025] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0026] The raw material pigment is selected from one of phthalocyanine blue, prussian blue, phthalocyanine green, lead chrome green, iron oxide red or composite titanium red, and the following embodiment selects prussian blue; the reaction monomer is selected from one or more of methyl trimethoxysilane, phenyl trimethoxysilane, methyl phenyl dimethoxysilane or vinyl trimethoxysilane, and the following embodiment selects a combination of methyl trimethoxysilane, phenyl trimethoxysilane and methyl phenyl dimethoxysilane; the surfactant is selected from one of sodium dodecyl sulfate, cetyl trimethyl ammonium bromide or alkyl phenol polyoxyethylene ether, and the following embodiment selects sodium dodecyl sulfate; the co-stabilizer is selected from one of n-hexadecane or cyclohexane, and the following embodiment selects n-hexadecane; and the hydrolysis-condensation catalyst is selected from one of an aqueous hydrochloric acid solution or ammonia water, wherein the concentration of the aqueous hydrochloric acid solution is 1.0wt%, the concentration of the ammonia water is 3.0wt%, and the following embodiment selects an aqueous hydrochloric acid solution with a concentration of 1.0wt%.

[0027] Example One

[0028] Reference Figure 1 The present embodiment provides a preparation method of a super-stable brush-shaped silicone microsphere coated modified pigment, comprising the following steps:

[0029] Step One, preparation of an organic silicone resin coated pigment composite pigment

[0030] Accurately weigh 0.2 g of Prussian blue pigment (PB) and 0.05 g of sodium dodecyl sulfate (SDS) into a 50 mL beaker A, and add 18.5 g of deionized water, then place the beaker A in an ice water bath, and start the ultrasonic cell crusher at a power of 150 W to ultrasonically disperse the mixture in beaker A for 2 minutes to obtain a pre-dispersed pigment solution, then accurately weigh 0.68 g of methyltrimethoxysilane (MTMS), 0.91 g of phenyltrimethoxysilane (PTMS), 0.99 g of methylphenyldimethoxysilane (MPDMS), 0.1 g of n-hexadecane (HD), and 0.05 g of sodium dodecyl sulfate (SDS) into a 50 mL beaker B, and add 18.5 g of deionized water, then place the beaker B in an ice water bath, and start the ultrasonic cell crusher at a power of 150 W to pre-emulsify the mixture in beaker B for 2 minutes to obtain a pre-emulsified monomer solution, then mix the pre-dispersed pigment solution and the pre-emulsified monomer solution and place them in an ice water bath, while starting the ultrasonic cell crusher at a power of 150 W to pre-emulsify for 2 minutes, after pre-emulsification, transfer the mixture to a 100 mL three-necked flask for mechanical stirring, after stirring is completed, place it in an oil bath heater to heat and warm up to 45-70℃, after heating to 55℃ in this example, add 10 g of 1.0 wt% hydrochloric acid aqueous solution at a dropping speed of 0.5 mL / min, and prepare a composite pigment emulsion coated with silicone by miniemulsion polymerization;

[0031] The particle size of the prepared composite pigment particles was measured by a laser particle size analyzer, and the results were as follows: when 0.1 g of SDS was added (in this example), the particle size of the prepared composite pigment particles was 257 nm, and the particle size distribution was 0.18; when 0.3 g of SDS was added, the particle size of the prepared composite pigment particles was 211 nm, and the particle size distribution was 0.10; when 0.5 g of SDS was added, the particle size of the prepared composite pigment particles was 198 nm, and the particle size distribution was 0.18;

[0032] Step two, preparation of brush-like silicone microsphere coated modified pigment

[0033] Accurately weigh 50 g of the prepared composite pigment emulsion coated with silicone (containing 0.8 g of solid mass) and 0.02 g of potassium persulfate (KPS) into a 100 mL three-necked flask and mechanically stir uniformly, then place the three-necked flask in an oil bath heater and heat and warm up to 70℃ under nitrogen protection and stabilize for 10 min, then add 1.6 g-3.2 g of acrylic acid (AA) monomer by means of a 5 mL syringe at a speed of 0.3-1.0 mL / min, the dropping speed in this example is 0.5 mL / min, and brush-like polyacrylic acid composite pigment is obtained by surface direct thermal initiation graft polymerization;

[0034] The particle size of the brush-shaped composite pigment particles prepared by direct thermal initiation method with different amounts of acrylic monomer is determined by a laser particle size analyzer, and the results are as follows: the particle size of the brush-shaped composite pigment particles prepared by adding 1.6 g of acrylic acid is 252 nm; the particle size of the brush-shaped composite pigment particles prepared by adding 2.4 g of acrylic acid is 485 nm; the particle size of the brush-shaped composite pigment particles prepared by adding 3.2 g of acrylic acid is 686 nm.

[0035] Example two

[0036] Referring to Figure 1 The present embodiment provides a preparation method of super-stable brush-shaped silicone microsphere coated modified pigment, comprising the following steps:

[0037] Step one, preparing composite pigment of silicone resin coated pigment

[0038] Accurately weigh 0.2 g of Prussian blue pigment (PB) and 0.15 g of sodium dodecyl sulfate (SDS) into a 50 mL beaker A, and add 18.4 g of deionized water, then place the beaker A in an ice water bath, and start the ultrasonic cell crusher at a power of 150 W to ultrasonically disperse the mixture in beaker A for 2 minutes to obtain a pre-dispersed pigment solution, then accurately weigh 0.68 g of methyltrimethoxysilane (MTMS), 0.91 g of phenyltrimethoxysilane (PTMS), 0.99 g of methylphenyldimethoxysilane (MPDMS), 0.1 g of n-hexadecane (HD) and 0.15 g of sodium dodecyl sulfate (SDS) into a 50 mL beaker B, and add 18.4 g of deionized water, then place the beaker B in an ice water bath, and start the ultrasonic cell crusher at a power of 150 W to pre-emulsify the mixture in beaker B for 2 minutes to obtain a pre-emulsified monomer solution, then mix the pre-dispersed pigment solution and the pre-emulsified monomer solution and place them in an ice water bath, and start the ultrasonic cell crusher at a power of 150 W to pre-emulsify for 2 minutes, then transfer the mixture to a 100 mL three-necked flask for mechanical stirring, and after stirring, place it in an oil bath to heat to 45-70℃, then add 10 g of 1.0 wt% hydrochloric acid aqueous solution at a dropping speed of 0.5 mL / min after heating to 55℃, and obtain a composite pigment emulsion coated with silicone on the surface by miniemulsion polymerization;

[0039] The particle size of the prepared composite pigment particles is determined by a laser particle size analyzer, and the results are as follows: when 0.1 g of SDS is added, the particle size of the prepared composite pigment particles is 257 nm, and the particle size distribution is 0.18; when 0.3 g of SDS is added (this embodiment), the particle size of the prepared composite pigment particles is 211 nm, and the particle size distribution is 0.10; when 0.5 g of SDS is added, the particle size of the prepared composite pigment particles is 198 nm, and the particle size distribution is 0.18;

[0040] Step 2: Preparation of brush-shaped organosilicon microspheres coated with modified pigments

[0041] 50g (containing 0.8g of solid mass) of the organosilicon-coated pigment emulsion prepared in step one and 0.02g of benzophenone were accurately weighed using a precision weighing instrument and transferred to a photoreactor. At the same time, 0.8g to 2.4g of hydroxyethyl acrylamide (HEAA) functional monomer were added to the photoreactor and mixed and stirred. Then, under nitrogen protection, a 175W ultraviolet radiation lamp was turned on to irradiate the mixture. The brush-shaped polyhydroxyethyl acrylamide composite pigment was obtained by direct photoinitiated graft polymerization.

[0042] The particle size of brush-shaped composite pigment particles prepared by direct photoinitiation under different amounts of hydroxyethyl acrylamide monomer was determined using a laser particle size analyzer. The results are as follows: the particle size of the brush-shaped composite pigment particles prepared with 0.8 g of hydroxyethyl acrylamide was 213 nm; the particle size of the brush-shaped composite pigment particles prepared with 1.6 g of hydroxyethyl acrylamide was 325 nm; and the particle size of the brush-shaped composite pigment particles prepared with 2.4 g of hydroxyethyl acrylamide was 390 nm.

[0043] like Figure 2 The results show the intensity and hydrodynamic diameter distribution of the composite pigment particles and the brush-shaped composite pigment particles. Figure 2 (a) represents composite pigment particles. Figure 2 (b) represents brush-shaped polyacrylic acid composite pigment particles. Figure 2 (c) represents brush-shaped polyhydroxyethylacrylamide composite pigment particles.

[0044] like Figure 3 The comparison of storage stability between brush-shaped polyhydroxyethylacrylamide composite pigment particles, brush-shaped polyacrylic acid composite pigment particles, and composite pigment particles is shown. Figure 3 (a) represents composite pigment particles. Figure 3 (b) represents brush-shaped polyacrylic acid composite pigment particles. Figure 3 (c) represents brush-shaped polyhydroxyethylacrylamide composite pigment particles.

[0045] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing ultra-stable brush-shaped organosilicon microspheres coated with modified pigments, characterized in that, Includes the following steps: Step 1: Weigh out the pigment, reactive monomer, surfactant, stabilizer, deionized water and hydrolysis-condensation catalyst in a mass ratio of 1:13:0.5~2.5:0.5:180~250:50 as raw materials. Then, use an ultrasonic cell disruptor to pre-emulsify the raw materials other than the hydrolysis-condensation catalyst. The pigment is selected from one of phthalocyanine blue, Prussian blue, phthalocyanine green, lead chromium green, iron oxide red, or composite titanium red, and the reaction monomer is selected from one or more of methyltrimethoxysilane, phenyltrimethoxysilane, methylphenyldimethoxysilane, or vinyltrimethoxysilane. The surfactant is selected from sodium dodecyl sulfate, hexadecyltrimethylammonium bromide or alkylphenol polyoxyethylene ether, and the stabilizer is selected from n-hexadecane or cyclohexane; The hydrolysis-condensation catalyst is selected from either hydrochloric acid aqueous solution or ammonia solution, wherein the concentration of hydrochloric acid aqueous solution is 1.0 wt% and the concentration of ammonia solution is 3.0 wt%. Step 2: Transfer the pre-emulsified mixture to a three-necked flask and heat it in an oil bath. After heating to the preset temperature, add the hydrolysis-condensation catalyst dropwise to the mixture at a uniform rate. Prepare a composite pigment emulsion with organosilicon coating by fine emulsion polymerization. Step 3: Weigh the composite pigment emulsion and initiator at a mass ratio of 40:1 as raw materials for later use. The mass ratio is the ratio of the solid mass in the composite pigment emulsion to the mass of the initiator. Then mix the weighed composite pigment emulsion and initiator and add graft monomers. Prepare a brush-shaped composite pigment by direct surface initiation graft polymerization, which is a brush-shaped organosilicon microsphere coated modified and functionalized pigment.

2. The method for preparing an ultra-stable brush-shaped organosilicon microsphere-coated modified pigment according to claim 1, characterized in that: In step two, the oil bath is heated to 45-70°C before the hydrolysis-condensation catalyst is added dropwise. The dropwise addition rate of the hydrolysis-condensation catalyst is 0.3-1.0 mL / min.

3. The method for preparing an ultra-stable brush-shaped organosilicon microsphere-coated modified pigment according to claim 1, characterized in that: In step three, the initiator is a thermal initiator, specifically selected from potassium persulfate or benzoyl peroxide. The specific steps for preparing the brush-like composite pigment with the thermal initiator are as follows: First, the weighed composite pigment emulsion and potassium persulfate are poured into a three-necked flask and mixed evenly. Then, the three-necked flask is placed in an oil bath and heated to 70°C under nitrogen protection and stabilized for 10 minutes. Then, 1.6g to 3.2g of grafted monomer is added dropwise to the three-necked flask at a uniform rate. The brush-like composite pigment is obtained by direct thermal initiation graft polymerization.

4. The method for preparing an ultra-stable brush-shaped organosilicon microsphere-coated modified pigment according to claim 3, characterized in that: The grafting monomer is selected from either an acrylic acid monomer or a hydroxyethyl acrylamide functional monomer, and the dropping rate of the grafting monomer is 0.3–1.0 mL / min.

5. The method for preparing an ultra-stable brush-shaped organosilicon microsphere-coated modified pigment according to claim 1, characterized in that: In step three, the initiator is a photoinitiator, specifically selected from benzophenone or azobisisobutyronitrile. The specific steps for preparing the brush-like composite pigment with the photoinitiator are as follows: First, the weighed composite pigment emulsion and benzophenone are poured into the photoreactor, and 0.8g to 2.4g of graft monomer is added and mixed. Then, under nitrogen protection, the ultraviolet radiation lamp is turned on to irradiate the mixture, and the brush-like composite pigment is obtained by direct surface photoinitiated graft polymerization.

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