阅读说明：本技术 一种水性纳米磁性黑板涂料及其制备方法 (Water-based nano magnetic blackboard paint and preparation method thereof ) 是由 张涛 何新波 于 2020-12-28 设计创作，主要内容包括：本发明公开了一种水性纳米磁性黑板涂料及其制备方法,该黑板涂料以永磁材料粉末为涂层原料,以有机硅改性丙烯酸酯乳液为聚合物乳液,选择适合的成膜助剂、分散剂、消泡剂、流平剂、防沉剂、防腐剂、防霉剂、pH调节剂等助剂,制备水性纳米磁性涂料,具有制备工艺简单,绿色环保等优点；且本发明的黑板涂料固化后的漆膜磁性强,漆膜硬度高,耐刮擦性好,并且具有良好的疏水性。同时该黑板涂料的制备工艺简单,成本低,直接在分散缸中完成制备的整体流程,适合大规模工业生产。(The invention discloses a water-based nano magnetic blackboard coating and a preparation method thereof, the blackboard coating takes permanent magnet material powder as a coating raw material, takes organic silicon modified acrylate emulsion as polymer emulsion, and selects proper film-forming auxiliary agents, dispersing agents, defoaming agents, flatting agents, anti-settling agents, preservatives, mildew inhibitors, pH regulators and other auxiliary agents to prepare the water-based nano magnetic coating, and the water-based nano magnetic coating has the advantages of simple preparation process, environmental protection and the like; the paint film of the cured blackboard paint has strong magnetism, high hardness, good scraping resistance and good hydrophobicity. Meanwhile, the preparation process of the blackboard paint is simple, the cost is low, the whole preparation process is directly completed in a dispersion cylinder, and the blackboard paint is suitable for large-scale industrial production.)

1. The water-based nano magnetic blackboard paint is characterized by being prepared from the following raw materials in percentage by weight:

wherein the weight percentages of the raw materials are all based on the total weight of the blackboard paint.

2. The aqueous nanometer magnetic blackboard paint of claim 1, wherein the magnetic material powder is permanent magnetic material powder.

3. The aqueous nanometer magnetic blackboard paint according to claim 2, wherein the permanent magnet material powder is one or more of an aluminum-nickel-cobalt system permanent magnet alloy material, an iron-chromium-cobalt system permanent magnet alloy material, a ferrite permanent magnet material and a rare earth permanent magnet material.

4. The aqueous nano magnetic blackboard paint according to claim 1, wherein the filler is precipitated barium sulfate and/or quartz powder.

5. The aqueous nano magnetic blackboard coating of claim 1, wherein the polymer emulsion is silicone modified acrylate emulsion.

6. The aqueous nano magnetic blackboard paint according to claim 1, wherein the film forming aid is one or more of alcohol ester-12, ethylene glycol, hexylene glycol butyl ether acetate, and propylene glycol phenyl ether.

7. The aqueous nano magnetic blackboard paint according to claim 1, wherein the anti-settling agent is one or more of polyurethane associative thickener and polyamide thickener.

8. The aqueous nano magnetic blackboard paint according to claim 1, characterized in that the dispersant is a polymer dispersant; the defoaming agent is one or more of a silicone defoaming agent and a polyether defoaming agent.

9. The aqueous nano magnetic blackboard paint according to claim 1, wherein the leveling agent is H6200; the preservative is JL-B509; the mildew preventive is iHeir-TQ; the pH regulator is AMP-95; the water is deionized water.

10. A method for preparing the aqueous nano magnetic blackboard paint according to any one of claims 1 to 9, characterized by comprising the following steps:

s1, magnetizing: magnetizing the magnetic material powder;

s2, premixing: sequentially adding water and a dispersant into a dispersion container under stirring, then adding a pH regulator to regulate the pH value of the mixed solution, and stirring for 10-60min to fully and uniformly mix the water and the dispersant;

s3, grinding and dispersing: sequentially adding magnetic material powder and a filler into the mixture obtained in the step S2, and grinding the mixture until the fineness is lower than 40 mu m;

s4, adding emulsion: adding the polymer emulsion into the mixture obtained in S3, and stirring for 10-60min to fully and uniformly mix;

s5, adding an auxiliary agent: and (4) adding a film forming auxiliary agent, a defoaming agent, a flatting agent, a preservative, a mildew preventive and an anti-settling agent into the system obtained in the step (S4), and stirring for 10-60min to obtain the water-based nano magnetic blackboard paint.

Technical Field

The invention belongs to the field of coatings, and particularly relates to a water-based nano magnetic blackboard coating and a preparation method thereof.

Background

Children are curious and like various forms of graffiti, the wall surfaces of families and schools can be used as graffiti places, teenagers can often use the blackboard in daily learning, and the traditional blackboard is generally oily paint and contains more organic solvents. The water-based blackboard paint is more environment-friendly than the traditional solvent-based blackboard paint, and the water-based paint can be constructed by blending clear water or deionized water. The diluents and curing agents indispensable to the conventional solvent-based blackboards contain a large amount of toxic components, and the water-based paint is environmentally friendly in that no diluents and curing agents are required. The existing traditional blackboard paint mainly adopts a solvent type, and the problems of high VOC content, serious pollution and fire hazard of the paint need to be solved. The existing water-based paint on the market has the problems that the paint is easy to drop and crack along with the increase of the using time, and further the blackboard is difficult to clean. In addition, the traditional blackboard paint is difficult to maintain the color for a long time, and the problems of color loss and the like can occur after repeated erasing and writing. Along with the improvement of the technological level, the demand of people on individual life is higher and higher, and the magnetic blackboard coating which is green, environment-friendly, has multiple functions and can show the individual character is more and more popular among people.

The patent with publication number CN108314945A discloses a blackboard and a preparation method thereof, wherein the blackboard comprises a substrate and a blackboard film coated on the surface of the substrate; the blackboard film is prepared from the following raw materials in parts by weight: 25-35 parts of water-based acrylic resin, 25-30 parts of deionized water, 5-7 parts of water-based amino resin, 10-15 parts of pigment and filler, 1-2 parts of graphite powder, 3-5 parts of nano titanium dioxide, 3-5 parts of talcum powder, 1-3 parts of dispersing agent, 1-3 parts of starch, 0.5-2.5 parts of chitosan, 0.5-1.5 parts of flatting agent, 1-2 parts of wetting agent, 0.5-1.5 parts of adhesion promoter, 0.2-0.4 part of defoaming agent, 0.2-0.4 part of potassium persulfate, 0.1-0.2 part of glycerol and 8-12 parts of purified konjac powder; wherein, the purified konjac powder refers to particles with the granularity of 0.125-0.425 mm, and the particle content of the konjac powder is more than 80%. The blackboard paint disclosed by the patent cannot be suitable for a blackboard needing magnetic force adsorption, and the application scene is limited.

Patent publication No. CN104629503A discloses a portable blackboard film substrate, an easily erasable portable blackboard film and a preparation method thereof, which are prepared from the following raw materials: the coating comprises water-based acrylate, pigment and filler, an auxiliary agent, hydroxypropyl methyl cellulose, polyethylene glycol, graphite powder, nano titanium dioxide, sodium dodecyl sulfate, talcum powder, deionized water, a leveling agent, a wetting agent, a thickening agent, an adhesion promoter and a cross-linking agent. According to the invention, the water-based acrylate is used as the film forming resin, so that the crosslinking density is improved, and the water resistance, the adhesive force and the strength of the film layer are improved; in addition, the water-based acrylate is a polar material, and the ink component in the white marker is generally a weak polar resin, so that the written note is convenient to wipe. The nanometer titanium dioxide and the talcum powder form a smooth paint surface under the action of the water-based polyethylene glycol and the surfactant sodium dodecyl sulfate, so that the erasability of the paint surface is improved. The black board film of the patent can not adsorb hard magnetic materials and soft magnetic materials, the application scene is limited, the required raw material components are more, and the preparation process is complex.

In conclusion, how to obtain the water-based nano magnetic blackboard paint by a low-cost and simple preparation method has great significance for the wide application of the magnetic blackboard paint.

Disclosure of Invention

The invention provides the aqueous nano magnetic blackboard coating and the preparation method thereof for solving the defects of the aqueous blackboard coating in the prior art, the blackboard coating takes permanent magnet material powder as a coating raw material, takes organic silicon modified acrylate emulsion as polymer emulsion, and selects proper film-forming auxiliary agents, dispersing agents, defoaming agents, flatting agents, anti-settling agents, preservatives, mildew inhibitors, pH regulators and other auxiliary agents to prepare the aqueous nano magnetic coating, and the aqueous nano magnetic coating has the advantages of simple preparation process, environmental protection and the like; the cured paint film has strong magnetism, high hardness, good scratch resistance and good hydrophobicity. Meanwhile, the preparation process of the blackboard paint is simple, the cost is low, the whole preparation process is directly completed in a dispersion container, and the blackboard paint is suitable for large-scale industrial production.

According to a first aspect of the invention, the invention provides a water-based nano magnetic blackboard paint, which is prepared from the following raw materials in percentage by weight:

wherein the weight percentages of the raw materials are all based on the total weight of the blackboard paint.

Preferably, in the method of the present invention, the magnetic material powder is a permanent magnetic material powder. According to the invention, the water-based nano magnetic coating is prepared by taking the permanent magnetic material powder as a coating raw material and selecting the fillers, the polymer emulsion, the film forming auxiliary agent, the dispersing agent, the defoaming agent, the leveling agent, the anti-settling agent, the preservative, the mildew preventive, the pH regulator and other auxiliary agents, so that the cured paint film has strong magnetism, high paint film hardness, good scratch resistance and good hydrophobicity.

Preferably, in the method of the present invention, the permanent magnet material powder is one or more of an aluminum-nickel-cobalt permanent magnet alloy material, an iron-chromium-cobalt permanent magnet alloy material, a ferrite permanent magnet material, and a rare earth permanent magnet material. The permanent magnetic material powder is used as a main pigment, and magnetic force exists among particles of the permanent magnetic material powder in the coating, so that the interaction with the polymer emulsion can be strengthened, and the solid content of the coating is improved, so that the coating has high magnetic force, not only can adsorb a hard magnetic material, but also can adsorb a soft magnetic material, and the application scene of the magnetic coating is widened.

Preferably, in the method of the present invention, the permanent magnet material powder is a rare earth permanent magnet material, the rare earth permanent magnet material is a samarium-based magnet or a neodymium-based magnet, the neodymium-based magnet is an ndfeb magnet, the rare earth permanent magnet material contains rare earth components, and the rare earth components include 30% of praseodymium and neodymium and 2% of dysprosium.

Preferably, in the method of the present invention, the ratio range of the magnetic material powder and the filler is: 4:3-10:1.

More preferably, in the method of the present invention, the ratio of the magnetic material powder to the filler is in the range of: 3:1-8:1.

More preferably, in the method of the present invention, the ratio of the magnetic material powder to the filler is: 3:1.

Preferably, in the method of the present invention, the filler is one or more of precipitated barium sulfate and quartz powder.

Preferably, in the method of the present invention, the filler is precipitated barium sulfate and quartz powder, and the ratio of the precipitated barium sulfate to the quartz powder is 1:1.

Preferably, the particle size of the magnetic material powder is 200-800 nm; the grain diameter of the filler is 20-50 μm; the particle size of the magnetic material powder is not too large or too small, and the proper particle size proportion is used for reducing the porosity and ensuring the magnetic force among the particles of the magnetic material powder. The magnetic material powder is matched with the filler, so that the magnetic material powder can be sufficiently ground in the grinding and dispersing process to reach the target particle size, and meanwhile, the quartz powder and the barium sulfate are used as the filler, so that the scratch resistance and the stain resistance of the coating can be improved.

More preferably, the particle size of the magnetic material powder is 350-650 nm.

Preferably, in the method of the present invention, the polymer emulsion is a silicone-modified acrylate emulsion. The organic silicon modified acrylate emulsion can not only exert excellent film-forming performance of acrylate in the film-forming process and ensure the bonding strength of the coating, but also facilitate the migration of silicon to the surface of the coating and exert the hydrophobic performance of organic silicon resin. Compared with water-based acrylate, the organosilicon modified acrylate has better erasing resistance because silicon element can migrate to the surface of a coating during film forming.

Preferably, in the method of the present invention, the coalescing agent is one or more of alcohol ester-12, ethylene glycol, hexylene glycol butyl ether acetate, and propylene glycol phenyl ether.

Preferably, in the method of the present invention, the anti-settling agent is one or more of a polyurethane associative thickener and a polyamide thickener. The polyamide thickener has strong persistence, anti-sagging and anti-settling properties, basically cannot be separated out, has little influence on glossiness and weather resistance, has strong universality, can be well compatible with various solvents and resins, does not need to accurately control temperature and prefabricate gel liquid, can improve the coordination of magnetic material powder, and has the function of directional arrangement.

Preferably, in the method of the present invention, the dispersant is a polymeric dispersant; the defoaming agent is one or more of a silicone defoaming agent and a polyether defoaming agent. The main component of the organic silicon defoamer is linear polysiloxane (also called silicone oil) which can keep liquid state at room temperature as an active agent, and the organic silicon defoamer has small surface tension, good thermal stability, good chemical stability, physiological inertia and strong defoaming capability; the polyether defoamer is a block polymer of polyoxypropylene and polyoxyethylene in the presence of an initiator, has excellent defoaming and foam inhibiting functions, is non-toxic, insoluble in water, soluble in an organic solvent, can be used independently or prepared into emulsion, wherein GPE is particularly suitable for fermentation industry, and PPE is suitable for high-temperature use.

More preferably, in the process of the present invention, the silicone-based antifoaming agent is a silicone oil-based antifoaming agent.

More preferably, in the process of the present invention, the polymeric dispersant is a BYK-199 polymeric wetting dispersant for aqueous systems.

Preferably, in the method of the present invention, the leveling agent is H6200, the H6200 leveling agent is an aqueous fluorine-containing anti-cratering leveling agent, and the leveling agent is a commercially available product; the preservative is JL-B509, the preservative JL-B509 is a high-efficiency industrial bactericide, and the preservative is a commercially available product; the mildew preventive is iHeir-TQ; the pH regulator is AMP-95; the water is deionized water.

H6200 leveling agent, mildew inhibitor iHeir-TQ, preservative JL-B509 and pH regulator are all commercial products; AMP-95 is used as 2-amino-2-methyl-1-propanol containing 5% of water and multifunctional auxiliary agent for blackboard paint, and can effectively reduce the cost of blackboard paint, prevent secondary flocculation of blackboard paint and improve the comprehensive performance of the paint. The paint preservative JL-B509 has high effect of killing bacteria, fungi and yeasts, and the required addition amount is small; the compatibility with polymer emulsion is good; is easy to dilute by water, and the pH value of the coating is adjusted by a pH regulator AMP-95 to be less than or equal to 9, and when the pH value is less than or equal to 9, the coating preservative JL-B509 is kept stable.

Preferably, in the invention, the aqueous nano magnetic blackboard paint is prepared from the following raw materials in percentage by weight:

according to a second aspect of the present invention, the present invention provides a method for preparing the above aqueous nano magnetic blackboard paint, comprising the steps of:

s1, magnetizing: magnetizing the magnetic material powder;

s2, premixing: sequentially adding water and a dispersant into a dispersion container under stirring, then adding a pH regulator to regulate the pH value of the mixed solution, and stirring for 10-60min to fully and uniformly mix the water and the dispersant;

s3, grinding and dispersing: sequentially adding magnetic material powder and a filler into the mixture obtained in the step S2, and grinding the mixture until the fineness is lower than 40 mu m;

s4, adding emulsion: adding the polymer emulsion into the mixture obtained in S3, and stirring for 10-60min to fully and uniformly mix;

s5, adding an auxiliary agent: and (4) adding a film forming auxiliary agent, a defoaming agent, a flatting agent, a preservative, a mildew preventive and an anti-settling agent into the system obtained in the step (S4), and stirring for 10-60min to obtain the water-based nano magnetic blackboard paint.

Preferably, in the present invention: a method for preparing the water-based nano magnetic blackboard paint comprises the following steps:

s1, magnetizing: magnetizing the magnetic material powder;

s2, premixing: sequentially adding water and a dispersing agent in a dispersing container under the condition of dispersing and stirring, stirring for 5min, adding a pH regulator to regulate the pH value of the mixed solution to 7-8, and stirring for 20min to fully and uniformly mix the water and the dispersing agent;

s3, grinding and dispersing: sequentially adding magnetic material powder and a filler into the mixture obtained in the step S2, and grinding the mixture until the fineness is lower than 40 mu m;

s4, adding emulsion: adding the polymer emulsion into the mixture obtained in the step S3, then adding the polymer emulsion while stirring, and dispersing for 20min to fully and uniformly mix the polymer emulsion;

s5, adding an auxiliary agent: and (4) adding a film-forming assistant, a defoaming agent, a flatting agent, a preservative, a mildew preventive and an anti-settling agent into the system obtained in the step (S4), and dispersing for 20min to obtain the water-based nano magnetic blackboard paint.

Preferably, in the method, the dispersion rotating speed of the dispersion container in the premixing process is 600r/min-800 r/min; the dispersion rotating speed of the dispersion container in the grinding dispersion process is 2500r/min-3000 r/min; the dispersion rotating speed of the dispersion container in the emulsion adding process is 800r/min-1200 r/min; the dispersing speed of the dispersing container in the process of adding the auxiliary agent is 800r/min-1200 r/min.

Preferably, in the method of the present invention, the fineness of the magnetic material powder and the filler during the grinding dispersion is measured by a blade fineness meter. This ensures that the particle diameter of the magnetic material powder after grinding reaches a desired value.

Preferably, in the present invention, the dispersion vessel is a dispersion cylinder.

Compared with the prior art, the invention has the following advantages:

1. the invention takes the permanent magnetic material powder as the coating raw material, takes the organic silicon modified acrylate emulsion as the polymer emulsion, and selects proper film-forming auxiliary agent, dispersant, defoamer, leveling agent, anti-settling agent, preservative, mildew preventive, pH regulator and other auxiliary agents to prepare the water-based nano magnetic coating, and has the advantages of simple preparation process, environmental protection and the like; the cured paint film has strong magnetism, high hardness, good scratch resistance and good hydrophobicity;

2. the invention takes the permanent magnetic material powder as the main raw material, the magnetic force exists between the permanent magnetic material powder in the coating, the interaction with the polymer emulsion is strengthened, and the solid content of the coating is improved, so that the coating has high magnetic force, not only can adsorb hard magnetic materials, but also can adsorb soft magnetic materials, and the application scene of the magnetic coating is widened; the organic silicon modified acrylate emulsion adopted by the invention can not only exert excellent film-forming property of acrylate and ensure the bonding strength of the coating, but also facilitate the migration of silicon to the surface of the coating and exert the hydrophobic property of organic silicon resin in the film-forming process; according to the invention, quartz powder and barium sulfate are used as fillers, so that the scratch resistance and stain resistance of the coating can be improved;

3. the invention overcomes the defect that the application scene of the blackboard paint in the prior art is limited, so that the magnetic blackboard paint has wider application scene, and the preparation method is simple and is more suitable for large-scale production.

Detailed Description

In order to make the objects and advantages of the invention more concise, the invention will be described in more detail with reference to the following examples, to which it is in no way limited. The following examples are merely preferred examples of the present invention and are only illustrative of the present invention and should not be construed as limiting the scope of the present invention. It should be understood that any modification, equivalent replacement, and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.

Examples of the invention

Inventive example 1

Firstly, preparing the following raw materials by weight:

wherein the particle size of the rare earth permanent magnet material powder is 500 nm; the particle size of the precipitated barium sulfate and quartz powder is 25 μm.

The preparation process of the aqueous nanometer magnetic blackboard paint of the embodiment is as follows:

(1) magnetizing the rare earth permanent magnet material powder;

(2) premixing: adding deionized water and a polymer dispersant into a dispersing container while stirring in sequence, stirring for 5min, adding AMP95 to adjust the pH value to 7-8, stirring for 20min to fully and uniformly mix the deionized water and the polymer dispersant, and controlling the rotating speed of the dispersing container to be 800 r/min;

(3) grinding and dispersing: sequentially adding rare earth permanent magnet material powder, precipitated barium sulfate and quartz powder into the mixture obtained in the step (2), dispersing and grinding at a high speed until the fineness is lower than 40 mu m, detecting the particle size of the mixed particles of the rare earth permanent magnet material powder, the precipitated barium sulfate and the quartz powder by a scraper fineness gauge, and controlling the rotating speed of a dispersing container at 2500 r/min;

(4) adding an emulsion: after high-speed grinding and dispersion, adding the organosilicon modified acrylate emulsion into the mixture obtained in the step (3) while stirring, and dispersing for 20min to fully and uniformly mix the mixture, wherein the rotating speed of a dispersing container is controlled at 1200 r/min;

(5) adding an auxiliary agent: and (3) adding alcohol ester-12, a polyurethane associative thickener, a silicone defoamer, an H6200 leveling agent, an iHeir-TQ mildew preventive and a JL-B509 preservative into the system obtained in the step (4), and dispersing for 20min to prepare the water-based nano magnetic blackboard paint, wherein the rotating speed of a dispersing container in the step is controlled at 800 r/min.

Inventive example 2

Firstly, preparing the following raw materials by weight:

the particle size of the aluminum-nickel-cobalt permanent magnetic alloy powder is 800 nm; the particle size of the quartz powder is 30 μm.

The preparation process of the aqueous nanometer magnetic blackboard paint of the embodiment is as follows:

(1) magnetizing the permanent magnetic alloy powder of the aluminum-nickel-cobalt system;

(2) premixing: adding deionized water and a polymer dispersant into a dispersing container while stirring in sequence, stirring for 5min, adding AMP95 to adjust the pH value to 7-8, stirring for 20min to fully and uniformly mix the deionized water and the polymer dispersant, and controlling the rotating speed of the dispersing container to be 800 r/min;

(3) grinding and dispersing: sequentially adding aluminum-nickel-cobalt permanent magnet alloy powder and quartz powder into the mixture obtained in the step (2), dispersing and grinding at a high speed until the fineness is lower than 45 mu m, detecting the particle size of the mixed rare earth permanent magnet material powder and quartz powder by a scraper blade fineness gauge, and controlling the rotating speed of a dispersing container at 2500 r/min;

(4) adding an emulsion: after high-speed grinding and dispersion, adding the organosilicon modified acrylate emulsion into the mixture obtained in the step (3) while stirring, and dispersing for 20min to fully and uniformly mix the mixture, wherein the rotating speed of a dispersing container is controlled at 1200 r/min;

(5) adding an auxiliary agent: adding hexanediol butyl ether acetate, a polyamide thickener, a polyether defoamer, an H6200 leveling agent, an iHeir-TQ mildew preventive and a JL-B509 preservative into the system obtained in the step (4), and dispersing for 20min to prepare the water-based nano magnetic blackboard paint, wherein the rotating speed of a dispersing container in the step is controlled at 800 r/min.

Inventive example 3

Firstly, preparing the following raw materials by weight:

the grain diameter of the iron-chromium-cobalt permanent magnetic alloy powder is 600 nm; the particle size of the precipitated barium sulfate is 35 mu m;

the preparation process of the aqueous nanometer magnetic blackboard paint of the embodiment is as follows:

(1) magnetizing iron-chromium-cobalt permanent magnet alloy powder;

(2) premixing: adding deionized water and a polymer dispersant into a dispersing container while stirring in sequence, stirring for 5min, adding AMP95 to adjust the pH value to 7-8, stirring for 20min to fully and uniformly mix the deionized water and the polymer dispersant, and controlling the rotating speed of the dispersing container to be 800 r/min;

(3) grinding and dispersing: sequentially adding iron-chromium-cobalt permanent magnet alloy powder and precipitated barium sulfate into the mixture obtained in the step (2), dispersing and grinding at a high speed until the fineness is lower than 40 mu m, detecting the particle size of the mixed iron-chromium-cobalt permanent magnet alloy powder and precipitated barium sulfate by a scraper blade fineness gauge, and controlling the rotating speed of a dispersing container at 2500 r/min;

(4) adding an emulsion: after high-speed grinding and dispersion, adding the organosilicon modified acrylate emulsion into the mixture obtained in the step (3) while stirring, and dispersing for 20min to fully and uniformly mix the mixture, wherein the rotating speed of a dispersing container is controlled at 1200 r/min;

(5) adding an auxiliary agent: and (3) sequentially adding propylene glycol phenyl ether, a polyamide thickener, a polyether defoamer, an H6200 leveling agent, an iHeir-TQ mildew preventive and a JL-B509 preservative into the system obtained in the step (4), and dispersing for 20min to prepare the water-based nano magnetic blackboard paint, wherein the rotating speed of a dispersing container in the step is controlled at 800 r/min.

Inventive example 4

Firstly, preparing the following raw materials by weight:

the particle size of the ferrite permanent magnet material powder is 600 nm; the particle size of the quartz powder is 35 mu m;

the preparation process of the aqueous nanometer magnetic blackboard paint of the embodiment is as follows:

(1) magnetizing ferrite permanent magnet material powder;

(2) premixing: adding deionized water and a polymer dispersant into a dispersing container while stirring in sequence, stirring for 5min, adding AMP95 to adjust the pH value to 7-8, stirring for 20min to fully and uniformly mix the deionized water and the polymer dispersant, and controlling the rotating speed of the dispersing container to be 800 r/min;

(3) grinding and dispersing: sequentially adding ferrite permanent magnet material powder and quartz powder into the mixture obtained in the step (2), dispersing and grinding at a high speed until the fineness is lower than 45 mu m, detecting the particle size of the mixed ferrite permanent magnet material powder and quartz powder by a scraper blade fineness gauge, and controlling the rotating speed of a dispersing container at 2500 r/min;

(4) adding an emulsion: after high-speed grinding and dispersion, adding the organosilicon modified acrylate emulsion into the mixture obtained in the step (3) while stirring, and dispersing for 20min to fully and uniformly mix the mixture, wherein the rotating speed of a dispersing container is controlled at 1200 r/min;

(5) adding an auxiliary agent: and (3) adding propylene glycol phenyl ether, a polyamide thickener, a polyether defoamer, an H6200 leveling agent, an iHeir-TQ mildew preventive and a JL-B509 preservative into the system obtained in the step (4), and dispersing for 20min to prepare the water-based nano magnetic blackboard paint, wherein the rotating speed of a dispersing container in the step is controlled at 800 r/min.

Inventive example 5

Firstly, preparing the following raw materials by weight:

the particle size of the ferrite permanent magnet material powder is 600 nm; the particle size of the quartz powder is 35 mu m;

the preparation process of the aqueous nanometer magnetic blackboard paint of the embodiment is as follows:

(1) magnetizing ferrite permanent magnet material powder;

(2) premixing: adding deionized water and a polymer dispersant into a dispersing container while stirring in sequence, stirring for 5min, adding AMP95 to adjust the pH value to 7-8, stirring for 20min to fully and uniformly mix the deionized water and the polymer dispersant, and controlling the rotating speed of the dispersing container to be 800 r/min;

(3) grinding and dispersing: sequentially adding ferrite permanent magnet material powder and quartz powder into the mixture obtained in the step (2), dispersing and grinding at a high speed until the fineness is lower than 45 mu m, detecting the particle size of the mixed ferrite permanent magnet material powder and quartz powder by a scraper blade fineness gauge, and controlling the rotating speed of a dispersing container at 2500 r/min;

(4) adding an emulsion: after high-speed grinding and dispersion, adding the organosilicon modified acrylate emulsion into the mixture obtained in the step (3) while stirring, and dispersing for 20min to fully and uniformly mix the mixture, wherein the rotating speed of a dispersing container is controlled at 1200 r/min;

(5) adding an auxiliary agent: and (3) adding ethylene glycol, a polyamide thickener, a polyether defoamer, an H6200 leveling agent, an iHeir-TQ mildew preventive and a JL-B509 preservative into the system obtained in the step (4), and dispersing for 20min to prepare the water-based nano magnetic blackboard paint, wherein the rotating speed of a dispersing container in the step is controlled at 800 r/min.

Inventive example 6

Firstly, preparing the following raw materials by weight:

the particle size of the ferrite permanent magnet material powder is 600 nm; the particle size of the quartz powder is 35 mu m;

the preparation process of the aqueous nanometer magnetic blackboard paint of the embodiment is as follows:

(1) magnetizing ferrite permanent magnet material powder;

(2) premixing: adding deionized water and a polymer dispersant into a dispersing container while stirring in sequence, stirring for 5min, adding AMP95 to adjust the pH value to 7-8, stirring for 20min to fully and uniformly mix the deionized water and the polymer dispersant, and controlling the rotating speed of the dispersing container to be 800 r/min;

(3) grinding and dispersing: sequentially adding ferrite permanent magnet material powder and quartz powder into the mixture obtained in the step (2), dispersing and grinding at a high speed until the fineness is lower than 45 mu m, detecting the particle size of the mixed ferrite permanent magnet material powder and quartz powder by a scraper blade fineness gauge, and controlling the rotating speed of a dispersing container at 2500 r/min;

(4) adding an emulsion: after high-speed grinding and dispersion, adding the organosilicon modified acrylate emulsion into the mixture obtained in the step (3) while stirring, and dispersing for 20min to fully and uniformly mix the mixture, wherein the rotating speed of a dispersing container is controlled at 1200 r/min;

(5) adding an auxiliary agent: and (3) adding ethylene glycol, a polyurethane associative thickener, a polyether defoamer, an H6200 leveling agent, an iHeir-TQ mildew preventive and a JL-B509 preservative into the system obtained in the step (4), and dispersing for 20min to obtain the water-based nano magnetic blackboard paint, wherein the rotating speed of a dispersing container in the step is controlled at 800 r/min.

Inventive example 7

Firstly, preparing the following raw materials by weight:

the particle size of the ferrite permanent magnet material powder is 600 nm; the particle size of the quartz powder is 35 mu m;

the preparation process of the aqueous nanometer magnetic blackboard paint of the embodiment is as follows:

(1) magnetizing ferrite permanent magnet material powder;

(2) premixing: adding deionized water and a polymer dispersant into a dispersing container while stirring in sequence, stirring for 5min, adding AMP95 to adjust the pH value to 7-8, stirring for 20min to fully and uniformly mix the deionized water and the polymer dispersant, and controlling the rotating speed of the dispersing container to be 800 r/min;

(3) grinding and dispersing: sequentially adding ferrite permanent magnet material powder and quartz powder into the mixture obtained in the step (2), dispersing and grinding at a high speed until the fineness is lower than 45 mu m, detecting the particle size of the mixed ferrite permanent magnet material powder and quartz powder by a scraper blade fineness gauge, and controlling the rotating speed of a dispersing container at 2500 r/min;

(4) adding an emulsion: after high-speed grinding and dispersion, adding the organosilicon modified acrylate emulsion into the mixture obtained in the step (3) while stirring, and dispersing for 20min to fully and uniformly mix the mixture, wherein the rotating speed of a dispersing container is controlled at 1200 r/min;

(5) adding an auxiliary agent: and (3) adding alcohol ester-12, ethylene glycol, a polyurethane associative thickener, a polyether defoamer, an H6200 leveling agent, an iHeir-TQ mildew preventive and a JL-B509 preservative into the system obtained in the step (4) in sequence, and dispersing for 20min to obtain the water-based nano magnetic blackboard paint, wherein the rotating speed of a dispersing container in the step is controlled at 800 r/min.

Comparative example

Comparative example 1

The other conditions were the same as in example 1 except that: the blackboard paint comprises the following raw materials:

the particle size of the precipitated barium sulfate and quartz powder is 25 μm. The preparation method of the blackboard paint in comparative example 1 does not include the step (1) of magnetizing the magnetic material split body, compared with example 1.

Comparative example 2

His conditions were identical to those of example 1, except that: the blackboard paint comprises the following raw materials:

the particle size of the rare earth permanent magnet material powder is 500 nm; the particle size of the precipitated barium sulfate and quartz powder is 25 μm.

Comparative example 3

The blackboard paint of comparative example 3 and example 1 had the same raw material composition, except that: the preparation process of the blackboard coating comprises the following steps:

(1) magnetizing the rare earth permanent magnet material powder;

(2) premixing: adding deionized water and a polymer dispersant into a dispersing container while stirring in sequence, stirring for 5min, adding AMP95 to adjust the pH value to 7-8, stirring for 20min to fully and uniformly mix the deionized water and the polymer dispersant, and controlling the rotating speed of the dispersing container to be 800 r/min;

(3) grinding and dispersing: sequentially adding rare earth permanent magnet material powder, precipitated barium sulfate and quartz powder into the mixture obtained in the step (2), dispersing and grinding at a high speed until the fineness is lower than 80 micrometers and higher than 45 micrometers, detecting the particle size of the mixed rare earth permanent magnet material powder, precipitated barium sulfate and quartz powder by using a scraper fineness meter, and controlling the rotating speed of a dispersing container at 2000 r/min;

(4) adding an emulsion: after high-speed grinding and dispersion, adding the organosilicon modified acrylate emulsion into the mixture obtained in the step (3) while stirring, and dispersing for 20min to fully and uniformly mix the mixture, wherein the rotating speed of a dispersing container is controlled at 1200 r/min;

(5) adding an auxiliary agent: and (3) adding alcohol ester-12, a polyurethane associative thickener, a silicone defoamer, an H6200 leveling agent, an iHeir-TQ mildew preventive and a JL-B509 preservative into the system obtained in the step (4) in sequence, and dispersing for 20min to obtain the water-based nano magnetic blackboard paint, wherein the rotating speed of a dispersing container in the step is controlled at 800 r/min.

Performance testing

The aqueous nano magnetic blackboard paints P1-P7 prepared in inventive examples 1-7 and blackboard paints prepared in comparative examples 1-3 were subjected to performance tests according to the following methods, and the results thereof are shown in table 1 below.

The performance test method comprises the following steps: the aqueous nano magnetic blackboard paint prepared in examples 1 to 7, the non-magnetic blackboard paint of comparative example 1 and the blackboard paint of comparative examples 2 to 3 were respectively used for preparing a magnetic blackboard coating by brushing, after the coating was dried, a magnet block and an iron block were used for adsorbing the magnetic blackboard coating, and a dust-free chalk was used for writing and wiping on the surface of the blackboard coating, and the specific performance test results are shown in the following table:

TABLE 1

	Magnet block adsorptivity	Iron block adsorption	Number of times of erasing and writing
				Example 1	Is that	Is that	More than 4000 times
Example 2	Is that	Is that	More than 4000 times
				Example 3	Is that	Is that	More than 4000 times
Example 4	Is that	Is that	More than 4000 times
				Example 5	Is that	Is that	More than 4000 times
Example 6	Is that	Is that	More than 4000 times
				Example 7	Is that	Is that	More than 4000 times
Comparative example 1	Whether or not	Whether or not	Less than 3800 times
				Comparative example 2	Is that	Whether or not	Less than 3300 times
Comparative example 3	Is that	Is that	Less than 3500 times

As can be seen from the above table, the method of the present invention uses the main raw materials of the permanent magnetic material powder, and the magnetic force exists between the permanent magnetic material powder to strengthen the interaction with the polymer emulsion and improve the solid content of the coating, so that the coating has high magnetic force, can adsorb both hard magnetic materials and soft magnetic materials, and can also adsorb metal materials, thereby widening the application scenarios of the magnetic coating; the invention adopts quartz powder and barium sulfate as fillers to match with the permanent magnetic material powder, thereby improving the scratch resistance of the blackboard coating. And the magnetic material powder must ensure sufficient quantity and fine grinding particle size to ensure that the blackboard coating has long enough scratch resistance under the condition of adsorbing the hard magnetic material and the soft magnetic material.

The above description is only an embodiment of the present application, but the scope of the present application is not limited thereto, and any changes or substitutions within the technical scope of the present disclosure should be covered by the scope of the present application. Therefore, the scope of the present application shall be determined by the scope of the appended claims, and variations and modifications of the above embodiments can be made by those skilled in the art based on the disclosure and teaching of the above description. Therefore, the scope of protection is not limited to the specific embodiments disclosed and described above, and some modifications and variations to the claims should fall within the scope of the invention. Furthermore, although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.