CN113088107A

CN113088107A - Second-level composite modifier with antibacterial property and application thereof in coating modified filler

Info

Publication number: CN113088107A
Application number: CN202110349750.XA
Authority: CN
Inventors: 王雄
Original assignee: Guangxi Fubaoxin Technology Co ltd
Current assignee: Guangxi Fubaoxin Technology Co ltd
Priority date: 2021-03-31
Filing date: 2021-03-31
Publication date: 2021-07-09

Abstract

The invention discloses a second-stage composite modifier with antibacterial property, which consists of 2-methyl-5-vinylpyridine, lauroyl sulfate deacetylated chitosan and trihydroxy triethylamine, and is applied to modified fillers, and comprises the following steps: (1) adding a first-stage composite modifier into clean coal ash for first modification to prepare a first mixture; (2) adding the first mixture prepared in the step (1), a secondary composite modifier and methyl ethyl ketone peroxide into a mixer for secondary modification to prepare a second mixture; (3) and (3) drying, grinding and sieving the second mixture prepared in the step (2) to obtain the modified coal ash. The invention adopts the secondary composite modifier consisting of 2-methyl-5-vinylpyridine, lauroyl sulfate chitosan and trihydroxy triethylamine to play a synergistic role in the modification of coal ash, thereby improving the antibacterial rate of the powder coating.

Description

Second-level composite modifier with antibacterial property and application thereof in coating modified filler

[ technical field ] A method for producing a semiconductor device

The invention belongs to the technical field of powder coating preparation, and particularly relates to a secondary composite modifier with antibacterial property and application thereof in coating modified filler.

[ background of the invention ]

Along with rapid take-off of industrial development, the use frequency of various motors is higher and higher, and for electrical equipment, an insulating material is an indispensable material, and insulativity is an indispensable assessment standard and is directly related to the use performance of the motor, thereby playing a decisive role in the use stability and the service life of the motor. The insulating paint is one kind of insulating material, and is coated on the surface of the conductor to form an insulating film, so as to play a role in insulation protection. The antibacterial coating industry is still in the development stage at present, and the application process of the antibacterial material in the coating is a common subject in the coating industry.

Chinese patent application document "an electrically insulating anticorrosive powder coating" (publication number: CN105754454A) "discloses an electrically insulating anticorrosive powder coating, which comprises the following components in parts by weight: 600 parts of epoxy resin, 82 parts of curing agent, 10 parts of flatting agent, 8 parts of brightening agent, 5 parts of benzoin, 2 parts of catalyst, 10 parts of defoaming dispersant, 20 parts of pigment, 150 parts of mica powder, 63 parts of silicon micropowder and 50 parts of flame retardant, wherein the epoxy resin is a mixture of bisphenol F epoxy resin and novolac epoxy resin, and the weight part ratio of the bisphenol F epoxy resin to the novolac epoxy resin is 2: 1. The electrical insulation anticorrosive powder coating has good electrical insulation property and corrosion resistance, but has low antibacterial property and high preparation cost.

Main component SiO of coal ash₂、Al₂O₃、Fe₃O₄And FeO, and a small amount of CaO, MgO and the like, so that the coal ash surface contains a large amount of hydroxyl groups, and if the unmodified coal ash is directly filled into the coating, the agglomeration effect in the matrix of the coal ash cannot be reduced, so that the caking property, the compatibility and the wettability between the unmodified coal ash and other raw materials of the powder coating, such as resin, are extremely poor, the apparent property and the gloss of the prepared powder coating are poor, the weather resistance is not high, and the application requirement of the powder coating cannot be met. How to creatively apply the coal ash in the powder coating and solve the problem of powder coating generationHigh production cost, environmental pollution caused by coal ash and the like, thereby realizing the industrial and industrialized application of the coal ash and having important economic and environmental benefits.

[ summary of the invention ]

The invention provides a second-level composite modifier with antibacterial property and application thereof in a coating modified filler, aiming at solving the problems of low antibacterial property, high cost and the like of powder coatings produced by the prior art.

In order to solve the technical problems, the invention adopts the following technical scheme:

a second-stage composite modifier with antibacterial property is composed of 2-methyl-5-vinylpyridine, lauroyl sulfate deacetylated chitosan and trihydroxy triethylamine.

Further, the mass ratio of the 2-methyl-5-vinylpyridine to the lauroyl sulfate chitosan to the trihydroxy triethylamine is 1:2.9: 6.4.

The invention also provides an application of the second-level composite modifier in the coating modified filler, which comprises the following steps:

(1) adding a first-stage composite modifier into clean coal ash for first modification to prepare a first mixture, wherein the first-stage composite modifier consists of coconut oil fatty acid diethylamide, hexa-polyglycerol monostearate and N-oleoyl-N-methyl sodium taurate;

(2) adding the first mixture prepared in the step (1), a secondary composite modifier and methyl ethyl ketone peroxide into a mixer, wherein the secondary composite modifier consists of 2-methyl-5-vinylpyridine, lauroyl sulfuric acid deacetylated chitosan and trihydroxy triethylamine, and performing secondary modification by controlling microwave power, temperature and speed to prepare a second mixture;

(3) and (3) drying, grinding and sieving the second mixture prepared in the step (2) to obtain the modified coal ash.

Further, the adding amount of the first-stage composite modifier in the step (1) is 4.7% of the mass of the clean coal ash.

Further, in the step (1), adding a first-stage composite modifier into the clean coal ash for first modification: stirring for 1.3h at the microwave power of 160W, the temperature of 63 ℃ and the rotating speed of 400 r/min.

Further, the adding amount of the secondary composite modifier in the step (2) is 2.7% of the mass of the clean coal ash.

Further, the adding amount of the methyl ethyl ketone peroxide in the step (2) is 0.5% of the mass of the clean coal ash.

Further, the conditions for the second modification in step (2): stirring for 2.6h at the microwave power of 250W, the temperature of 110 ℃ and the rotating speed of 500 r/min.

The invention has the following beneficial effects:

the 2-methyl-5-vinylpyridine, lauroyl sulfate chitosan and trihydroxy triethylamine are adopted to play a synergistic role in the modification of coal ash, so that the antibacterial rate of the powder coating is improved, because: after the coal ash is modified for the first time, 2-methyl-5-vinylpyridine, lauroyl sulfate deacetylated chitosan and trihydroxy triethylamine are adopted for carrying out secondary modification, and the 2-methyl-5-vinylpyridine, the lauroyl sulfate deacetylated chitosan and the trihydroxy triethylamine contain groups such as pyridyl and amino, so that antibacterial groups such as pyridyl and amino can be introduced to the surface of coal ash particles during secondary modification, under the mutual cooperation of the components, the antibacterial components are contacted with staphylococcus aureus and then adsorbed to the surface of the bacteria to penetrate cell walls, the composition of cell membranes is disturbed through the change of osmotic pressure and the decomposition of organic matters, the leakage of intracellular substances (DNA and RNA) is promoted, and the staphylococcus aureus can be effectively killed. In addition, the introduced antibacterial groups such as pyridyl, amino and the like are concentrated on the surface of the coal ash, so that the concentration is increased, the sterilization time is shortened, and the effect is effectively improved.

[ description of the drawings ]

FIG. 1 is a black and white drawing of an electrically insulating powder coating product of preferred embodiment 3 of the present invention.

[ detailed description ] embodiments

In order to facilitate a better understanding of the invention, the following examples are given to illustrate, but not to limit the scope of the invention.

In an embodiment, a process for producing an electrically insulating powder coating, comprises the steps of:

a. mixing raw materials: mixing various raw materials according to mass percentage, then respectively adding the raw materials into a mixing machine, then pre-crushing for 1min, and then mixing for 4min to prepare uniformly mixed raw materials;

the raw materials in percentage by mass are as follows: 32.8 to 38.1 percent of modified coal ash, 44.6 to 50.2 percent of epoxy resin, 7.2 to 9.1 percent of curing agent, 0.1 to 0.2 percent of accelerant, 1.2 to 1.8 percent of flatting agent, 0.3 to 0.8 percent of benzoin, 0.5 to 0.9 percent of defoaming agent, 0.3 to 0.5 percent of dispersing agent, 0.7 to 0.9 percent of brightener and 0.4 to 0.6 percent of pigment.

The epoxy resin is hydrogenated bisphenol A epoxy resin ST-3000.

The curing agent is a BTDA curing agent.

The accelerant is 2-methylimidazole.

The leveling agent is a PV88 leveling agent.

The defoaming agent is a polyoxyethylene polyoxypropylene amine ether defoaming agent.

The dispersant is dispersant NC.

The brightener is 701B brightener.

The pigment is phthalocyanine green.

The preparation method of the modified coal ash comprises the following steps:

the method comprises the following steps: washing the coal ash with hydrochloric acid with the mass concentration of 29.1% until the pH value of the coal ash is 8.9, then washing the washed coal ash with water, detecting the pH value of the washed coal ash to be 7.4, and performing filter pressing treatment to obtain clean coal ash, wherein the clean coal ash is dried at the temperature of 75 ℃ until the water content is 1.7%;

step two: grinding the clean coal ash obtained in the step one, and sieving to obtain clean coal ash with the particle size of more than 400 meshes;

step three: adding a first-stage composite modifier into the clean coal ash prepared in the second step, wherein the first-stage composite modifier consists of coconut oil fatty acid diethylamide, hexa-polyglycerol monostearate and N-oleoyl-N-methyl sodium taurate, the adding amount of the first-stage composite modifier is 4.7% of the mass of the clean coal ash, the mass ratio of the coconut oil fatty acid diethylamide to the hexa-polyglycerol monostearate to the N-oleoyl-N-methyl sodium taurate is 4.2:1:8.9, and stirring is carried out for 1.3 hours at the microwave power of 160W, the temperature of 63 ℃ and the rotating speed of 400r/min to prepare a first mixture;

step four: adding the first mixture prepared in the third step, a second-stage composite modifier and methyl ethyl ketone peroxide into a mixer, wherein the second-stage composite modifier comprises 2-methyl-5-vinylpyridine, lauroyl sulfuric acid deacetylated chitosan and trihydroxy triethylamine, the addition amount of the second-stage composite modifier is 2.7% of the mass of the clean coal ash, the addition amount of the methyl ethyl ketone peroxide is 0.5% of the mass of the clean coal ash, the mass ratio of the 2-methyl-5-vinylpyridine to the lauroyl sulfuric acid deacetylated chitosan to the trihydroxy triethylamine is 1:2.9:6.4, stirring for 2.6 hours at the microwave power of 250W and the rotation speed of 500r/min, and preparing a second mixture;

step five: drying the second mixture prepared in the fourth step at the temperature of 62 ℃ until the water content is 0.9%, grinding the dried second mixture into powder, and sieving the powder to obtain modified coal ash with the particle size of more than 400 meshes;

b. melt extrusion: b, putting the uniformly mixed raw materials prepared in the step a into an extruder, performing melt extrusion, tabletting and cooling, and then crushing into sheet materials, wherein the melt extrusion temperature is 105-110 ℃, and the temperature in the area I is 105 ℃ and the temperature in the area II is 110 ℃;

c. grinding and crushing: and c, placing the crushed sheet materials in the step b into an ACM (Acetobacter caldroni) pulverizer for pulverizing, and performing cyclone separation and screening to obtain the electrically insulating powder coating with the average particle size of 52.1-59.7 mu m.

In order to further illustrate the present invention and make the disclosure more complete, more specific embodiments are described below.

EXAMPLE 1

A process for producing an electrically insulating powder coating, comprising the steps of:

the raw materials in percentage by mass are as follows: 35.8% of modified coal ash, 49.8% of epoxy resin, 8.9% of curing agent, 0.2% of accelerator, 1.7% of flatting agent, 0.8% of benzoin, 0.9% of defoaming agent, 0.5% of dispersing agent, 0.8% of brightener and 0.6% of pigment.

The epoxy resin is hydrogenated bisphenol A epoxy resin ST-3000.

The curing agent is a BTDA curing agent.

The accelerant is 2-methylimidazole.

The leveling agent is a PV88 leveling agent.

The dispersant is dispersant NC.

The brightener is 701B brightener.

The pigment is phthalocyanine green.

The preparation method of the modified coal ash comprises the following steps:

step five: and (3) drying the second mixture prepared in the fourth step at the temperature of 62 ℃ until the water content is 0.9%, grinding the dried mixture into powder, and sieving the powder to obtain the modified coal ash with the particle size of more than 400 meshes.

The modified coal ash prepared above was subjected to infrared characterization (FTIR) and electron microscopy Scanning (SEM).

Infrared characterization (FTIR): the modified coal ash is repeatedly washed by absolute ethyl alcohol and acetone, vacuum-dried and potassium bromide tabletted, and a Nicolet 67 model Fourier infrared spectrometer produced by the American Thermo Nicolet company is adopted to record the characteristic peak of the surface of the modified coal ash. Resolution of 1cm^-1The number of scans was 16.

FT-IR analysis shows that the amido, carbonyl, sulfonic acid, pyridyl, amino and other groups are successfully grafted to the surface of the coal ash particle.

Electron microscopy Scanning (SEM): the modified coal ash is filled in a resin matrix (epoxy resin) to obtain a sample, the normal-temperature notch impact section of the sample is subjected to metal spraying treatment, and a tungsten filament scanning electron microscope is used for observing the surface morphology at the voltage of 20 KV. Instrument model JSM-6490LV, manufactured by Japan.

SEM analysis shows that the modified coal ash has increased compatibility with the resin matrix (epoxy resin), and the modified coal ash is well dispersed in the resin matrix (epoxy resin).

c. grinding and crushing: and c, placing the crushed sheet materials in the step b into an ACM (acid-activated metal) pulverizer for pulverizing, and performing cyclone separation and screening to obtain the electrically insulating powder coating with the average particle size of 56.3 mu m.

EXAMPLE 2

the raw materials in percentage by mass are as follows: 38.1% of modified coal ash, 48.8% of epoxy resin, 8.8% of curing agent, 0.1% of accelerator, 1.7% of flatting agent, 0.4% of benzoin, 0.6% of defoaming agent, 0.3% of dispersing agent, 0.8% of brightener and 0.4% of pigment.

The epoxy resin is hydrogenated bisphenol A epoxy resin ST-3000.

The curing agent is a BTDA curing agent.

The accelerant is 2-methylimidazole.

The leveling agent is a PV88 leveling agent.

The dispersant is dispersant NC.

The brightener is 701B brightener.

The pigment is phthalocyanine green.

The preparation method of the modified coal ash comprises the following steps:

c. grinding and crushing: and c, placing the crushed sheet materials in the step b into an ACM (Acetobacter caldroni) pulverizer for pulverizing, and performing cyclone separation and screening to obtain the electrically insulating powder coating with the average particle size of 53.4 mu m.

EXAMPLE 3

the raw materials in percentage by mass are as follows: 37.6 percent of modified coal ash, 48.2 percent of epoxy resin, 9 percent of curing agent, 0.2 percent of accelerant, 1.6 percent of flatting agent, 0.7 percent of benzoin, 0.8 percent of defoaming agent, 0.5 percent of dispersing agent, 0.8 percent of brightener and 0.6 percent of pigment.

The epoxy resin is hydrogenated bisphenol A epoxy resin ST-3000.

The curing agent is a BTDA curing agent.

The accelerant is 2-methylimidazole.

The leveling agent is a PV88 leveling agent.

The dispersant is dispersant NC.

The brightener is 701B brightener.

The pigment is phthalocyanine green.

The preparation method of the modified coal ash comprises the following steps:

c. grinding and crushing: and c, putting the crushed sheet materials in the step b into an ACM (Acetobacter xylinum) mill for milling, and obtaining the electrically insulating powder coating with the average particle size of 57.8 mu m after cyclone separation and screening, wherein the black and white picture of the product is shown in figure 1.

Comparative example 1

The process for preparing an electrically insulating powder coating was substantially the same as that of example 3, except that only the modification of step four was performed in the preparation of the modified coal ash, and the modification of step three was not performed.

Comparative example 2

The electrically insulating powder coating was prepared by a process substantially identical to that of example 3, except that the primary composite modifier used in the preparation of the modified coal ash lacked coconut oil fatty acid diethylamide.

Comparative example 3

The process for preparing the electrically insulating powder coating was substantially the same as that of example 3, except that the primary composite modifier used in the preparation of the modified coal ash lacked hexaglycerol monostearate.

Comparative example 4

The process for preparing the electrically insulating powder coating was substantially the same as that of example 3, except that the primary composite modifier used in the preparation of the modified coal ash lacked N-oleoyl-N-methyltaurate.

Comparative example 5

The process for preparing an electrically insulating powder coating was substantially the same as that of example 3, except that only the modification of step three was performed in the preparation of the modified coal ash, and the modification of step four was not performed.

Comparative example 6

The process for preparing an electrically insulating powder coating was substantially the same as that of example 3, except that the second-order composite modifier used in the preparation of the modified coal ash lacked 2-methyl-5-vinylpyridine.

Comparative example 7

The process for preparing the electrically insulating powder coating was substantially the same as that of example 3, except that the secondary composite modifier used in the preparation of the modified coal ash lacked lauroyl sulfated chitosan.

Comparative example 8

The preparation process of the electrical insulation powder coating is basically the same as that of example 3, except that the second-order composite modifier used in the preparation of the modified coal ash lacks trihydroxy triethylamine.

Comparative example 9

The preparation process of the electrically insulating powder coating was substantially the same as that of example 3, except that the modified coal ash was not modified in the third and fourth steps.

Comparative example 10

The electrically insulating powder coating prepared by the process of example 1 of the Chinese patent application document "an electrically insulating anticorrosive powder coating" (publication No. CN105754454A) "was used.

And (3) performance detection:

preparing a coating layer: the electrically insulating powder coatings of examples 1 to 3 and comparative examples 1 to 4 and 9 were sprayed on the surface-treated cold-rolled steel sheets using an electrostatic spray gun, the thickness of the coating films was substantially uniform, and the coating films were cured at 200 ℃/10min to give coating layers corresponding to examples 1 to 3 and comparative examples 1 to 4 and 9, the gloss being measured using GB/T1743-1979.

The results of coating tests of examples 1 to 3 and comparative examples 1 to 4 and 9 are shown in Table 1.

TABLE 1 coating test results of examples 1-3 and comparative examples 1-4, 9

Experimental project	Apparent appearance of coating film	Gloss (60 degree specular gloss),% of
			Example 1	Smooth and pore-free	76.4
Example 2	Smooth and pore-free	74.3
			Example 3	Smooth and pore-free	78.5
Comparative example 1	Rough, unsmooth and porous	50.6
			Comparative example 2	Basically flat and smooth without air holes	67.8
Comparative example 3	Basically flat and smooth without air holes	72.1
			Comparative example 4	Basically flat and smooth without air holes	70.5
Comparative example 9	Rough, unsmooth and porous	39.4

As can be seen from Table 1: (1) as can be seen from the data of example 3 and comparative examples 1-4, coconut oil fatty acid diacetic amide, hexa-polyglycerol monostearate, and sodium N-oleoyl-N-methyltaurate act synergistically in coal ash modification to improve the apparent performance and gloss of the coating film of the electrically insulating powder coating; this is:

the polyester resin is non-polar, and the unmodified coal ash is alkaline, contains a large amount of hydroxyl on the surface, and has a complex result, so that the electrical insulation powder coating prepared by directly filling the unmodified coal ash into the polyester resin has poor appearance and gloss. The coal ash is subjected to surface modification by coconut oil fatty acid diethylamide, hexapolyglycerol monostearate and N-oleoyl-N-methyl sodium taurate at a certain microwave and temperature, and because the coconut oil fatty acid diethylamide, the hexapolyglycerol monostearate and the N-oleoyl-N-methyl sodium taurate contain amide, long-carbon-chain fatty acid, carbonyl, sulfonic group and other groups, amide, long-carbon-chain fatty acid, carbonyl, sulfonic group and other groups can be introduced into the surface of coal ash particles during the first modification, not only can the processing fluidity and the dispersibility of the modified coal ash be improved, but also the modified coal ash is changed from hydrophilicity to lipophilicity, and the modified coal ash and other raw materials of the electrical insulation powder coating, such as polyester resin, have better cohesiveness, wettability and compatibility, and the interfacial cohesive force of the coating of the electrical insulation powder coating is improved, further improving the apparent property and the gloss of the coating film of the electric insulating powder coating.

(2) As can be seen from the data of examples 1-3 and comparative example 9, the electrically insulating powder coatings produced using the modified coal ash exhibited improved film appearance and gloss of at least 88.6% as compared to powder coatings produced using unmodified coal ash.

The impact strength, puncture strength, antibacterial rate, volume resistivity, and salt spray resistance of the electrically insulating powder coatings prepared in examples 1 to 3 and comparative examples 5 to 8, and 10 were measured, wherein the impact strength was measured using GB/T1732-93; the breakdown strength is detected by GB 6554-2003; the antibacterial rate is detected by GB/T21866-2008, wherein the bacteria are staphylococcus aureus; the volume resistivity is detected by GB 6554-2003; the salt spray resistance was measured by GB/T1771-1991, and the results are shown in Table 2 below.

TABLE 2 tables of results of performance tests of the powder coatings obtained in examples 1 to 3 and comparative examples 5 to 8 and 10

As can be seen from Table 2:

(1) as can be seen from the data of example 3 and comparative examples 5-8, 2-methyl-5-vinylpyridine, lauroyl chitosan sulfate, trihydroxy triethylamine have a synergistic effect in the modification of coal ash, increasing the antibacterial rate of the powder coating, which is:

after the coal ash is modified for the first time, 2-methyl-5-vinylpyridine, lauroyl sulfate deacetylated chitosan and trihydroxy triethylamine are adopted for carrying out secondary modification, and the 2-methyl-5-vinylpyridine, the lauroyl sulfate deacetylated chitosan and the trihydroxy triethylamine contain groups such as pyridyl and amino, so that antibacterial groups such as pyridyl and amino can be introduced to the surface of coal ash particles during secondary modification, under the mutual cooperation of the components, the antibacterial components are contacted with staphylococcus aureus and then adsorbed to the surface of the bacteria to penetrate cell walls, the composition of cell membranes is disturbed through the change of osmotic pressure and the decomposition of organic matters, the leakage of intracellular substances (DNA and RNA) is promoted, and the staphylococcus aureus can be effectively killed. In addition, the introduced antibacterial groups such as pyridyl, amino and the like are concentrated on the surface of the coal ash, so that the concentration is increased, the sterilization time is shortened, and the effect is effectively improved.

(2) As can be seen from the data of examples 1-3, the impact strength of the electrically insulating powder coating of the invention is 50.6-55.4kg/cm, an improvement of at least 54.3% over the prior art (comparative example 10); the breakdown strength is 38.7-43.5kv/mm, which is improved by at least 59.3% compared with the prior art (comparative example 10); the antibacterial rate is 96.82-98.78%, which is at least 65.1% higher than that of the prior art (comparative example 10); volume resistivity of 5.6X 10¹⁴-6.5×10¹⁴Ω. cm, at least 60% higher than the prior art (comparative example 10); the salt spray resistance was 1179-.

(3) The invention effectively solves the problem of poor weather resistance of powder coating obtained by using traditional coal ash as filler after modifying the coal ash, the filler is filled into the prepared electric insulation powder coating, the filling amount is up to more than 32.8 percent, compared with the conventional filler such as mica powder, the filler has good filling performance, and can effectively reduce the production cost (because the cost for purchasing waste coal ash is extremely low, the waste coal ash is used as raw material, and the modified coal ash obtained after modification is used as filler, the cost for preparing the modified coal ash filler is far less than that of the conventional filler mica powder, and is about more than 540 yuan/ton less, therefore, the production cost for preparing the electric insulation powder coating can be effectively reduced).

(4) As can be seen from the data of examples 1-3, example 3 of the present invention is the most preferred example, and when the modified coal ash loading in example 3 is 37.6%, the electrically insulating powder coating achieves the best overall performance, wherein the impact strength is 55.4kg/cm, the breakdown strength is 42.1kv/mm, the antibacterial property is 98.78%, and the volume resistivity is 6.5X 10¹⁴Omega cm, and the salt spray resistance is 1231h, which provides basis for seeking the optimal process for producing the electric insulation powder coating.

The above description should not be taken as limiting the invention to the embodiments, but rather, as will be apparent to those skilled in the art to which the invention pertains, numerous simplifications or substitutions may be made without departing from the spirit of the invention, which shall be deemed to fall within the scope of the invention as defined by the claims appended hereto.

Claims

1. A second-stage composite modifier with antibacterial property is characterized in that: the secondary composite modifier consists of 2-methyl-5-vinylpyridine, lauroyl sulfate deacetylated chitosan and trihydroxy triethylamine.

2. The antibacterial secondary composite modifier of claim 1, wherein: the mass ratio of the 2-methyl-5-vinylpyridine to the lauroyl sulfate chitosan to the trihydroxy triethylamine is 1:2.9: 6.4.

3. The application of the two-stage composite modifier according to claim 1 or 2 in coating material modified fillers is characterized by comprising the following steps:

4. The use of the secondary composite modifier in a coating modified filler according to claim 3, wherein: the addition amount of the primary composite modifier in the step (1) is 4.7 percent of the mass of the clean coal ash.

5. The use of the secondary composite modifier in a coating modified filler according to claim 3, wherein: adding a first-stage composite modifier into the clean coal ash in the step (1) to carry out first modification: stirring for 1.3h at the microwave power of 160W, the temperature of 63 ℃ and the rotating speed of 400 r/min.

6. The use of the secondary composite modifier in a coating modified filler according to claim 3, wherein: the addition amount of the secondary composite modifier in the step (2) is 2.7 percent of the mass of the clean coal ash.

7. The use of the secondary composite modifier in a coating modified filler according to claim 3, wherein: the adding amount of the methyl ethyl ketone peroxide in the step (2) is 0.5 percent of the mass of the clean coal ash.

8. The use of the secondary composite modifier in a coating modified filler according to claim 3, wherein: the conditions for the second modification in the step (2) are as follows: stirring for 2.6h at the microwave power of 250W, the temperature of 110 ℃ and the rotating speed of 500 r/min.