CN114163777B

CN114163777B - Mica composite material of internal-added short fibers for new energy automobile and preparation process

Info

Publication number: CN114163777B
Application number: CN202210128055.5A
Authority: CN
Inventors: 黄静; 周培学; 孙虎
Original assignee: Zhejiang Rongtai Electrical Equipment Co ltd
Current assignee: Zhejiang Rongtai Electrical Equipment Co ltd
Priority date: 2022-02-11
Filing date: 2022-02-11
Publication date: 2022-06-28
Anticipated expiration: 2042-02-11
Also published as: CN114163777A

Abstract

The application relates to the field of mica insulation materials, and particularly discloses a mica composite material of an internal-adding short fiber for a new energy automobile and a preparation process. The mica composite material comprises 18-26 parts of modified mica powder, 6-12 parts of adhesive, 2-8 parts of modified ceramic powder and 3-5 parts of modified aramid fiber; the preparation method comprises the following steps: adding an adhesive into the modified mica powder, the modified ceramic powder and the modified aramid fiber, uniformly mixing, injecting into a three-dimensional die, stirring, and heating for molding. The mica composite material of the internal short fiber added for the new energy automobile can be used for protecting the battery of the new energy automobile, and has the advantages of good compatibility of mica and a reinforcing material and high mechanical strength; in addition, the preparation method has the advantages that the special-shaped three-dimensional mica is integrally formed, the electrical insulation effect of each point of the prepared special-shaped three-dimensional mica is kept consistent, and the electrical strength is high.

Description

Mica composite material of internal-added short fibers for new energy automobile and preparation process

Technical Field

The application relates to the field of mica composite materials, in particular to a mica composite material with internally-increased short fibers for a new energy automobile and a preparation process thereof.

Background

The insulating material is a material for isolating the charged body from other parts in an electrical apparatus, is an important guarantee that an electrical product can run safely for a long time, and is a key material for directly influencing the advanced degree of technical indexes of the electrical product. Mica is a special sheet silicate mineral, the crystal structure of which is a lamellar structure consisting of two silicon-oxygen tetrahedrons sandwiching one aluminum-oxygen octahedron, and the structure determines that the crystal structure has extremely high electrical insulation property on a plane perpendicular to a cleavage plane, and simultaneously has the characteristics of good strippability, chemical stability, reducibility and capability of keeping the excellent physical and chemical properties at a high temperature, and is 'industrial monosodium glutamate' which is indispensable for electrical insulation materials.

At present, an insulating material can be used for protecting a battery of a new energy automobile, and when the insulating material for protecting the battery is manufactured and an insulating mica plate is manufactured, mica powder is firstly used for preparing mica slurry, the mica slurry is poured into a funnel with filter paper, and the mica paper is formed after vacuum filtration and drying. And coating the organic silicon resin on the surface of the mica paper, overlapping the mica paper to a certain thickness, pressing the overlapped mica plate, and drying at high temperature to obtain the mica plate.

In view of the above-mentioned related technologies, the applicant believes that it is difficult to keep the electrical strength of each point where the mica paper is adhered to be consistent in the process of manufacturing the mica paper, and the electrical strength of the insulating mica plate is reduced, so that electrical breakdown is easy to occur, and the battery cannot be effectively protected.

Disclosure of Invention

In order to solve the problem of low electrical strength of a mica plate in the related technical problems, the application provides a mica composite material of an internal-added short fiber for a new energy automobile and a preparation process thereof.

In a first aspect, the application provides a mica composite material of an internal-added short fiber for a new energy automobile, which adopts the following technical scheme:

the mica composite material of the internal short fiber added for the new energy automobile is prepared from the following raw materials in parts by weight: 18-26 parts of modified mica powder, 6-12 parts of adhesive, 2-8 parts of modified ceramic powder and 3-5 parts of modified aramid fiber, wherein the surface of the modified mica powder is provided with concave-convex parts, and the surfaces of the modified ceramic powder and the modified aramid fiber are both provided with concave parts.

By adopting the technical scheme, the concave-convex representation structure is formed on the surface of the mica, so that the mica has a larger specific surface area and a rough surface matrix, the mica is easy to form mechanical engagement with the modified aramid fiber and the modified ceramic powder, and the compatibility of the mica with the modified ceramic powder and the modified aramid fiber is improved; meanwhile, the added modified aramid fiber improves the bending strength of the mica composite material, and the added modified ceramic powder improves the high-temperature resistance and the electrical strength of the mica composite material, so that the mica composite material has the effects of good compatibility of mica and a reinforcing material, high mechanical strength and high electrical strength.

Preferably, the modified aramid fiber is prepared from the following raw materials in parts by weight: 6-10 parts of aramid fiber, 1-2 parts of sodium hydroxide, 0.3-0.8 part of polyoxyethylene and 0.2-0.4 part of sodium dodecyl benzene sulfonate; wherein the length of the aramid fiber is 3-10 mm; the modified aramid fiber is prepared by the following method: putting the aramid fiber into a sodium hydroxide solution, adding sodium dodecyl benzene sulfonate and polyethylene oxide, uniformly stirring, reacting for 20-30min, taking out, and drying.

By adopting the technical scheme, because the surface crystallinity of the aramid fiber is high, the mica surface is compact and smooth, the inertia is strong, the interface bonding performance of the aramid fiber and a mica material is poor, the strength of the composite material is low, the surface of the aramid fiber is etched by sodium hydroxide to form a surface concave structure, the specific surface area of the aramid fiber is increased, the surface of the aramid fiber is roughened, the compatibility of the aramid fiber and the mica material is improved, and the possibility of interface separation between the aramid fiber and a matrix under the action of cracks of the aramid fiber is reduced.

Preferably, the modified mica powder is prepared from the following raw materials in parts by weight: 1-3 parts of tris (hydroxymethyl) aminomethane hydrochloride, 0.2-0.6 part of sodium hydroxide, 0.5-2 parts of dopamine hydrochloride and 22-25 parts of mica powder; the mica powder comprises coarse-fraction mica with the particle size of 250-550um and fine-fraction mica with the particle size of 74-150um, wherein the weight ratio of the coarse-fraction mica to the fine-fraction mica is 1: 3.

By adopting the technical scheme, alkaline solution of dopamine is prepared by using tris (hydroxymethyl) aminomethane hydrochloride, sodium hydroxide and dopamine hydrochloride, and the dopamine is continuously deposited on the mica surface in the alkaline solution through self-polymerization, so that an uneven structure is formed on the mica surface, and the specific surface area of the mica surface is increased;

meanwhile, the mica composite material has a structure with coarse-grain mica as a framework structure and is filled with fine-grain mica, so that the density of the mica composite material is maximized, and further, the reasonable grain size distribution is realized.

Preferably, the preparation of the modified mica powder comprises the following steps:

b1, washing mica powder with deionized water, drying, and grinding the mica powder into coarse-fraction mica and fine-fraction mica;

b2, preparing a trihydroxymethylaminomethane hydrochloride buffer solution with the pH of 8.5 by using sodium hydroxide and trihydroxymethylaminomethane hydrochloride, adding dopamine hydrochloride to prepare a dopamine solution, adding coarse-fraction mica and fine-fraction mica into the dopamine solution, stirring for 6-7h, taking out the modified mica, and drying.

By adopting the technical scheme, dopamine is continuously deposited on the mica surface through self-polymerization in an alkaline solution to form a convex appearance on the mica surface, so that the trihydroxymethyl aminomethane hydrochloride buffer solution with the pH value of 8.5 is firstly adjusted, and dopamine hydrochloride is added, so that dopamine is easily self-polymerized on the mica surface and deposited on the mica surface, the characteristic structure of mica is improved, and then the compatibility of mica powder modified by the dopamine solution and aramid fiber is good, and the purpose of improving the overall mechanical property is realized.

Preferably, the modified ceramic powder is prepared from the following raw materials in parts by weight: 2-4 parts of tertiary butanol, 1-2 parts of acrylamide, 2-4 parts of methylene bisacrylamide, 0.5-1 part of ammonium persulfate, 0.2-0.8 part of tetramethyl ethylenediamine and 7-16 parts of ceramic powder.

By adopting the technical scheme, acrylamide and methylene bisacrylamide can generate polymerization reaction under the action of ammonium persulfate and tetramethylethylenediamine, so that the curing and forming are realized, tert-butyl alcohol can volatilize in the curing process, air phase is introduced into the ceramic material, the ceramic material is endowed with a concave structure, the obtained concave structure ceramic material has lower density than a compact ceramic material, higher specific surface area and lower thermal conductivity, the formed concave cavity structure improves the thermal insulation performance of modified ceramic powder, and meanwhile, the modified mica and the modified aramid fiber can be combined with the concave part of the modified ceramic powder, so that the using amount of an adhesive is reduced.

Preferably, the preparation of the modified ceramic powder comprises the following steps:

c1, heating tert-butyl alcohol into liquid, and uniformly mixing with acrylamide and methylene bisacrylamide to prepare a mixed solution A;

c2, adding the ceramic powder into the mixed solution A and uniformly mixing;

c3, adding ammonium persulfate and tetramethylethylenediamine into the mixed solution obtained in the step c2, uniformly stirring again, and pouring into a mold after uniformly stirring;

c4, heating the die to 50-60 ℃, heating for 13-15h, demoulding and taking out, heating to 550 ℃ of 450-;

c5, crushing the modified ceramic block in the step c4 to 150-200 meshes.

By adopting the technical scheme, at the temperature of 50-60 ℃, heating is carried out for 13-15h, acrylamide and methylene bisacrylamide in the ceramic powder slurry are subjected to polymerization reaction under the action of ammonium persulfate and tetramethylethylenediamine, so as to be cured and molded, and after being taken out, heating is carried out for 2-3h at the temperature of 450-550 ℃ so as to volatilize tert-butyl alcohol.

Preferably, the adhesive comprises a mixed solution B, methylated amino resin and dibenzoyl peroxide, wherein the mixed solution B is prepared from the following raw materials in parts by weight: 8-10 parts of organic silicon epoxy resin, 5-8 parts of polyethylene glycol, 0.6-2 parts of phthalic anhydride, 0.8-3 parts of maleic anhydride, 0.1-0.6 part of dimethylethanolamine and 0.5-0.9 part of diethylene glycol monobutyl ether.

By adopting the technical scheme, the organic silicon epoxy resin is compounded by adopting the polyethylene glycol, the phthalic anhydride and the maleic anhydride, the polyethylene glycol has good hydrophilicity and can be added to the main chain of the epoxy resin in a nucleophilic mode under the action of hydrogen ions, the phthalic anhydride and the maleic anhydride react with the epoxy group and the hydroxyl group under the action of alcoholysis, and the carboxyl group is introduced.

Preferably, the preparation of the mixed solution B includes the steps of:

d1, adding 1/3-3/5 mass percent of polyethylene glycol, 1/6-1/5 mass percent of phthalic anhydride, 1/6-1/5 mass percent of maleic anhydride and diethylene glycol butyl ether into the organic silicon epoxy resin, uniformly stirring, raising the temperature to 180 ℃ and 210 ℃, and reacting for 2-3 h;

d2, adding the rest of polyethylene glycol, the rest of phthalic anhydride and the rest of maleic anhydride into the step d1, stirring uniformly, controlling the reaction temperature at 140-160 ℃, adding dimethylethanolamine after measuring the acid value at 50mgKOH/g, adjusting the pH value to 7-8.5, and stirring to obtain a mixed solution B.

By adopting the technical scheme, the content of polyethylene glycol at the initial reaction stage is higher by adopting a mode of distributed feeding, the polyethylene glycol can react with more epoxy groups to form epoxy resin-polyethylene glycol block macromolecules, after the reaction is continued for a period of time, the contents of maleic anhydride and phthalic anhydride are higher, the polyethylene glycol reacts with secondary hydroxyl of an epoxy main chain, the esterification reaction of maleic anhydride, phthalic anhydride and polyethylene glycol is inhibited, the esterification reaction of maleic anhydride, phthalic anhydride and epoxy groups is also inhibited, the reaction is smoothly carried out, the generation of byproducts in the reaction process is effectively reduced, the hydrophilic performance of the adhesive is improved, the modified aramid fiber, the modified mica powder, the modified ceramic powder and the adhesive are easily mixed, and the dispersion effect is improved.

In a second aspect, the application provides a preparation process of a mica composite material of an internal reinforced short fiber for a new energy automobile, which comprises the following steps:

S1, preparation of raw materials: modified mica powder, modified ceramic powder and modified aramid fiber;

s2, adding a hydroxypropyl methyl cellulose solution and a polyacrylamide solution, then adding modified mica powder, modified ceramic powder and modified aramid fiber, heating and uniformly stirring to prepare mica slurry;

s3, adding dibenzoyl peroxide into the mica slurry obtained in the step S2, and stirring and dispersing the mixture evenly;

s4, adding the mixed solution B and methylated amino resin in the step S3, and uniformly stirring;

s5, compression molding, heating the mold to 40-80 ℃, heating for 4-6h, heating to 150-170 ℃, heating for 1-2h, taking out the mica blank, heating to 200-230 ℃, heating for 1-2min, taking out, cooling and preparing for molding.

By adopting the technical scheme, the dibenzoyl peroxide is added firstly to initiate polymerization reaction, and then the methylated amino resin is added and then the mixture is heated gradually, so that the problem of exhaust is solved, the mica with different particle sizes is utilized, the resource utilization rate is improved, the VOC emission is reduced, and the environmental pollution is improved.

Preferably, the three-dimensional mold in the step S5 includes an upper mold and a lower mold, the upper mold is fixedly connected with an air cylinder, a mold groove is formed between the upper mold and the lower mold, the mold groove and the mica green body are manufactured in a 1: 1 reduction effect, a slurry hole for feeding mica slurry is formed in the upper surface of the upper mold, and the slurry hole is communicated with the mold groove.

Through adopting above-mentioned technical scheme, operator's accessible thick liquids hole pours into the mica thick liquids into the mould inslot into, through heating the mould afterwards to prepare the shaping with mica composite material, at last through the piston rod that removes the cylinder, thereby take out fashioned mould.

In summary, the present application has the following beneficial effects:

1. the mica is modified by the dopamine solution, so that dopamine is self-polymerized and deposited on the surface of the mica in the alkaline solution, the compatibility of the mica material with aramid fiber and ceramic powder is improved, the structural strength of the mica composite material is further improved, the using amount of an adhesive is reduced, and higher structural strength is obtained; meanwhile, the use amount of the adhesive is reduced, so that the electrical strength of the mica composite material is improved;

2. the tertiary butanol is introduced when the ceramic is fired at high temperature, so that the ceramic surface is sunken in the ceramic firing process, and the heat insulation performance of the mica composite material is improved; meanwhile, the modified aramid fiber, the modified mica powder and the modified ceramic powder are provided with the depressions on the surfaces, so that mechanical meshing is easy to form, the compatibility of the mica composite material is improved, and the integral mechanical property and structural strength are further improved;

3. The base material raw stock is prepared by uniformly mixing the modified ceramic powder, the modified aramid fiber, the modified mica powder and the adhesive and is injected into a three-dimensional die for integral pressing and forming, so that the mica composite material has the advantages of high integration degree, high structural strength and electrical strength consistency at each position, and high electrical strength and structural strength.

Detailed Description

Raw materials

Reagent	CAS number
		Tris hydroxymethyl aminomethane hydrochloride	1185-53-1
Dopamine hydrochloride	62-31-7
		Phthalic anhydride	85-44-9
Maleic anhydride	108-31-6
		Dimethylethanolamine	108-01-0
Diethylene glycol butyl ether	112-34-5
		Dibenzoyl peroxide	94-36-0
Tert-butyl alcohol	75-65-0
		Acrylamide	79-06-1
Methylene bisacrylamide	110-26-9
		Ammonium persulfate	7727-54-0
Tetramethyl ethylene diamine	110-18-9
		Polyethylene oxide	68441-17-8
Sodium dodecyl benzene sulfonate	25155-30-0

The methylated amino resin can be aqueous methylated amino resin 717 of chemical Limited of Jinan Hua, Jinan province;

the silicone epoxy resin can be Japanese shin-Etsu silicone epoxy resin ES 1001N;

the aramid fiber can be aramid 1414 short fiber, and the selected length is 3-5 mm;

preparation example 1, modified mica powder was prepared, which was prepared from the following raw materials in parts by weight:

0.60kg of coarse mica, 1.80kg of fine mica, 0.2kg of tris hydrochloride, 0.04kg of sodium hydroxide and 0.1kg of dopamine hydrochloride.

The preparation of the modified mica powder comprises the following steps:

b1, washing mica powder by deionized water, drying, grinding the mica powder into coarse-fraction mica of 250-550um and fine-fraction mica of 74-150um by using a ball mill;

2, preparing a trihydroxymethylaminomethane hydrochloride buffer solution with the pH value of 8.5 by using 0.04kg of sodium hydroxide and 0.2kg of trihydroxymethylaminomethane hydrochloride, adding 0.1kg of dopamine hydrochloride to prepare a dopamine solution, pouring 0.60kg of coarse-fraction mica and 1.80kg of fine-fraction mica into the dopamine solution, stirring for 7 hours by using a high-speed stirrer to prepare modified mica, taking out the prepared modified mica, and drying.

Preparation example 2, unmodified mica powder was prepared, and the difference between the preparation example 2 and the preparation example 1 is that: washing mica powder with deionized water, drying, grinding the mica powder into coarse-fraction mica of 250-550um and fine-fraction mica of 74-150um by using a ball mill, and selecting 0.60kg of the coarse-fraction mica and 1.80kg of the fine-fraction mica.

Preparation example 3, a modified aramid fiber was prepared, which was prepared from the following raw materials in parts by weight:

0.8kg of aramid fiber, 0.2kg of sodium hydroxide, 0.05kg of polyethylene oxide and 0.03kg of sodium dodecyl benzene sulfonate.

The preparation of the modified aramid fiber comprises the following steps: shearing 0.8kg of aramid fiber to 3-5mm, putting 0.8kg of aramid fiber into 0.2kg of sodium hydroxide solution, adding 0.03kg of sodium dodecyl benzene sulfonate and 0.05kg of polyoxyethylene, uniformly stirring by using a stirrer at a stirring speed of 100r/min, reacting for 30min, taking out, and drying.

Preparation example 4, preparing unmodified aramid fiber, selecting 0.8kg of raw material aramid fiber, and shearing the raw material aramid fiber to 3-5 mm.

Preparation example 5 modified ceramic powder was prepared, which was prepared from the following raw materials in parts by weight:

0.2kg of t-butanol, 0.1kg of acrylamide, 0.2kg of methylenebisacrylamide, 0.05kg of ammonium persulfate, 0.04kg of tetramethylethylenediamine and 1kg of ceramic powder.

The preparation of the modified ceramic powder comprises the following steps:

c1, heating 0.2kg of tertiary butanol in a water bath to ensure that the tertiary butanol is in a liquid state, and uniformly mixing 0.2kg of tertiary butanol, 0.1kg of acrylamide and 0.2kg of methylene bisacrylamide to prepare a mixed solution A;

c2, adding 1kg of ceramic powder into the mixed solution A and uniformly mixing;

c3, adding 0.05kg of ammonium persulfate and 0.04kg of tetramethylethylenediamine into the mixed solution in the step c2, uniformly stirring again, and pouring into a mold after uniformly stirring;

c4, heating the die to 60 ℃, demoulding after heating for 15h, taking out, heating to 500 ℃, heating for 3h, taking out, heating to 750 ℃, preserving heat for 3min, cooling to room temperature, and taking out;

c5, crushing the modified ceramic blank taken out from the step c4 to 150-200 meshes.

Preparation example 6 unmodified ceramic powder was prepared by selecting 1kg of raw ceramic powder and pulverizing it to 150-mesh 200-mesh.

Preparation example 7, an adhesive was prepared, the adhesive including mixed solution B, methylated amino resin, dibenzoyl peroxide, the mixed solution B being prepared from the following raw materials in parts by weight:

0.09kg of organic silicon epoxy resin, 0.06kg of polyethylene glycol, 0.01kg of phthalic anhydride, 0.02kg of maleic anhydride, 0.002kg of dimethyl ethanol anhydride and 0.008kg of diethylene glycol butyl ether.

The preparation of the mixed solution B comprises the following steps:

d1, adding 0.02kg of polyethylene glycol, 0.0017kg of phthalic anhydride, 0.0034kg of maleic anhydride and 0.008kg of diethylene glycol monobutyl ether into 0.09kg of organic silicon epoxy resin, uniformly stirring, raising the temperature to 200 ℃, and reacting for 2.5 hours;

d2, adding the rest of polyethylene glycol, the rest of phthalic anhydride and the rest of maleic anhydride into the step d1, uniformly stirring, controlling the reaction temperature to be 150 ℃, measuring the acid value to be 50mg/KOHg, adding dimethylethanolamine, adjusting the pH to be 7, and stirring to obtain a mixed solution B.

Preparation 8, preparation 8 differs from preparation 7 in that polyethylene glycol, phthalic anhydride, maleic anhydride were added in one portion.

Examples

Example 1, a mica composite material was prepared from the following raw materials in parts by weight: 0.18kg of the modified mica powder prepared in preparation example 1, 0.02kg of the modified ceramic powder prepared in preparation example 5, 0.03kg of the modified aramid fiber prepared in preparation example 3, and 0.09kg of the adhesive prepared in preparation example 7, wherein the adhesive comprises 0.082kg of mixed solution B, 0.004kg of dibenzoyl peroxide and 0.004kg of methylated amino resin.

A preparation process of a mica composite material with internally-added short fibers for a new energy automobile comprises the following steps:

s1, preparation of raw materials: 0.18kg of modified mica powder, 0.02kg of modified ceramic powder and 0.03kg of modified aramid fiber;

s2, adding 0.01kg of hydroxypropyl methyl cellulose solution and 0.02kg of polyacrylamide solution into a beaker, then adding 0.18kg of modified mica powder, 0.02kg of modified ceramic powder and 0.03kg of modified aramid fiber, raising the temperature to 80 ℃, stirring for 20min by a high-speed stirrer at the stirring speed of 100r/min, and preparing mica slurry;

s3, adding 0.004kg of dibenzoyl peroxide into the mica slurry obtained in the step S2, and stirring for 20min by a high-speed stirrer at a stirring speed of 100r/min to uniformly disperse the dibenzoyl peroxide;

s4, adding 0.082kg of mixed liquor B and 0.004kg of methylated amino resin in the step S3, and stirring for 20min by a high-speed stirrer at a stirring speed of 100r/min to uniformly disperse the mixture;

s5, injecting the stirred slurry into a three-dimensional mold, heating the mold to 60 ℃, heating for 5h, heating to 160 ℃, heating for 1.5h, taking out the mica green body, heating to 210 ℃, heating for 2min, taking out, cooling, and preparing and molding; the three-dimensional die in the step S5 comprises an upper die and a lower die, the upper die is fixedly connected with a cylinder, a die groove is formed between the upper die and the lower die, the die groove and the mica green body are manufactured in a 1: 1 reshaping effect, a slurry hole for feeding mica slurry is formed in the upper surface of the upper die, and the slurry hole is communicated with the die groove;

And S6, injecting the mica slurry into the die groove through the slurry hole, enabling the piston rod of the air cylinder to move downwards, enabling the upper die to extrude downwards to the lower die, extruding redundant slurry, heating the die, forming the mica composite material, enabling the upper die to move upwards, taking out the mica composite material in the die groove, heating the mica composite material, removing impurities in the mica material, and forming the mica composite material.

Example 2, example 2 differs from example 1 in that: the modified mica in step S1 was 0.22 kg.

Example 3, example 3 differs from example 2 in that: the modified mica in step S1 was 0.24 kg.

Example 4, example 4 differs from example 2 in that: the modified ceramic powder in steps S1 and S2 was 0.05 kg.

Example 5, example 5 differs from example 2 in that: the modified ceramic powder in steps S1 and S2 was 0.08 kg.

Example 6, example 6 differs from example 4 in that: the modified aramid fiber in steps S1 and S2 was 0.04 kg.

Example 7, example 7 differs from example 4 in that: the modified aramid fiber in steps S1 and S2 was 0.05 kg.

Example 8, example 8 differs from example 6 in that: the adhesive prepared in preparation example 7 was selected to be 0.06kg, which included 0.055kg of mixed solution B, 0.0025kg of dibenzoyl peroxide, and 0.0025kg of methylated amino resin.

Example 9, example 9 differs from example 6 in that: the adhesive prepared in preparation example 7 was selected to be 0.12kg, which included 0.11kg of the mixed solution B, 0.005kg of dibenzoyl peroxide, and 0.005kg of methylated amino resin.

Table 1 shows the material ratios of examples 1 to 9

Mica powder

Ceramic powder

Aramid fiber

Mixed liquor B

Methylated amino resin

Dibenzoyl peroxide

Example 1

0.18kg

0.02kg

0.03kg

0.082kg

0.004kg

Example 2

0.22kg

0.02kg

0.03kg

0.082kg

0.004kg

Example 3

0.24kg

0.02kg

0.03kg

0.082kg

0.004kg

Example 4

0.22kg

0.05kg

0.03kg

0.082kg

0.004kg

Example 5

0.22kg

0.08kg

0.03kg

0.082kg

0.004kg

Example 6

0.22kg

0.05kg

0.04kg

0.082kg

0.004kg

Example 7

0.22kg

0.05kg

0.082kg

0.004kg

Example 8

0.22kg

0.05kg

0.04kg

0.055kg

0.0025kg

Example 9

0.22kg

0.05kg

0.04kg

0.11kg

0.005kg

Comparative example

Comparative example 1, comparative example 1 differs from example 1 in that: in the steps S1 and S2, the mass of the modified mica powder is 0.15 kg.

Comparative example 2, comparative example 2 differs from example 1 in that: in the steps S1 and S2, the mass of the modified mica powder is 0.29 kg.

Comparative example 3, comparative example 3 differs from example 1 in that: 0.18kg of the unmodified mica prepared in production example 2 selected in step S1 and step S2.

Comparative example 4, comparative example 4 differs from example 1 in that: the modified ceramic powder used in step S1 and step S2 was 0.005 kg.

Comparative example 5, comparative example 5 differs from example 1 in that: the amount of the modified ceramic powder selected in the steps S1 and S2 was 0.1 kg.

Comparative example 6, comparative example 6 differs from example 1 in that: in steps S1 and S2, 0.02kg of the unmodified ceramic powder prepared in preparation example 6 was selected.

Comparative example 7, comparative example 7 differs from example 1 in that: 0.01kg of modified aramid fibers is selected in the steps S1 and S2.

Comparative example 8, comparative example 8 differs from example 1 in that: 0.07kg of modified aramid fibers is selected in the steps S1 and S2.

Comparative example 9, comparative example 9 differs from example 1 in that: in steps S1 and S2, 0.03kg of the unmodified aramid fiber prepared in preparation example 4 was selected.

Comparative example 10, comparative example 10 differs from example 9 in that: 0.04kg of the adhesive prepared in preparation example 7 selected in step S1 and step S2, wherein the adhesive includes 0.036kg of the mixed solution B, 0.0018kg of dibenzoyl peroxide, and 0.0018kg of methylated amino resin.

Comparative example 11, comparative example 11 differs from example 9 in that: 0.14kg of the adhesive prepared in preparation example 7 selected in step S1 and step S2, wherein the adhesive comprises 0.128kg of mixed solution B, 0.0063kg of dibenzoyl peroxide and 0.0063kg of methylated amino resin.

Comparative example 12, comparative example 12 differs from example 1 in that: the adhesive used was the adhesive prepared in preparation example 8, and the amount of adhesive used was 0.09kg, including 0.082kg of mixed solution B, 0.004kg of dibenzoyl peroxide, and 0.004kg of methylated amino resin.

Comparative example 13:

s1, selecting raw materials: selecting 0.18kg of modified mica powder, 0.02kg of modified ceramic powder, 0.03kg of modified aramid fiber and 0.09kg of organic silicon resin adhesive; the modified mica powder prepared in the preparation example 1 is selected as the modified mica powder; the modified aramid fiber prepared in preparation example 3 can be selected as the modified aramid fiber, and the modified ceramic powder prepared in preparation example 5 can be selected as the modified ceramic powder.

S2, adding modified mica powder, modified ceramic powder and modified aramid fiber into a beaker, then adding 0.01kg of hydroxypropyl methyl cellulose and 0.02kg of polyacrylamide, adding deionized water, raising the temperature to 80 ℃, stirring for 20min by a high-speed stirrer at a stirring speed of 100r/min, and preparing mica slurry;

s3: mixing and defibering the mica slurry obtained in the step S2 for 2000 turns, immediately adding the mixture into a paper sheet former, quickly stirring up and down, discharging water, forming, and drying by a drier at 105 ℃ for 30min to prepare mica paper; coating an organic silicon resin adhesive on the surface of mica paper, bonding adjacent mica paper, hot-pressing, controlling the temperature at 130 ℃, and reacting for 30min to prepare the composite mica plate.

S5: composite mica plates with different sizes are prepared, an organic silicon resin adhesive is coated at the edges of the composite mica plates, so that the mica composite plates are mutually bonded, and finally the special-shaped mica composite plate with the same structure as that of the embodiment 1 is prepared according to the proportion of 1: 1.

Table 2 shows the material ratios of comparative examples 1 to 13

Mica powder

Ceramic powder

Aramid fiber

Mixed liquor B

Methylated amino resin

Diphenyl formyl peroxide

Comparative example 1

0.15kg

0.02kg

0.03kg

0.082kg

0.004kg

Comparative example 2

0.29kg

0.02kg

0.03kg

0.082kg

0.004kg

Comparative example 3

0.18kg

0.02kg

0.03kg

0.082kg

0.004kg

Comparative example 4

0.18kg

0.005kg

0.03kg

0.082kg

0.004kg

Comparative example 5

0.18kg

0.1kg

0.03kg

0.082kg

0.004kg

Comparative example 6

0.18kg

0.02kg

0.03kg

0.082kg

0.004kg

Comparative example 7

0.18kg

0.02kg

0.01kg

0.082kg

0.004kg

Comparative example 8

0.18kg

0.02kg

0.07kg

0.082kg

0.004kg

Comparative example 9

0.18kg

0.02kg

0.03kg

0.082kg

0.004kg

Comparative example 10

0.22kg

0.05kg

0.04kg

0.036kg

0.0018kg

Comparative example 11

0.22kg

0.05kg

0.04kg

0.128kg

0.0063kg

Comparative example 12

0.18kg

0.02kg

0.03kg

0.082kg

0.004kg

Comparative example 13

0.18kg

0.02kg

0.03kg

0.082kg

0.004kg

Performance test

Electric strength

The test is carried out according to the part 1 of the test method for the electrical strength of the insulating material of the national standard GB/T1408.1-2006: the test is carried out under power frequency, the thickness is 0.4mm, a phi 25 mm/phi 75mm cylindrical electrode system is adopted, the detection is carried out in a rapid boosting mode (the boosting speed is 1.0 kV/s), the test is carried out in 25# transformer oil at the temperature of 23 ℃, the test frequency is 5 times, and the test can be carried out on the same sample.

Bending strength

When the bending strength of the mica composite material is measured according to the national standard GB/T9341-2008 'determination of plastic bending performance', five samples are respectively taken along a direction parallel to one edge of the sample and vertical to the edge, the length of each sample is not less than 20 times of the thickness of the sample to be measured, the length of each sample is 80mm, the width of each sample is 10mm, the thickness of each sample is 4mm, the test span is 16mm, the test speed is 50mm/min, the radius of an indenter is 5mm, the performance is measured at 23 ℃ and 155 ℃, and the bending strength is the median value of five measurements.

Detection method/test method

Table 3 shows the data of the performance tests of examples 1 to 9 and comparative examples 1 to 13

As can be seen by combining examples 1-3, comparative examples 1-3 and by combining Table 3: the electrical strength of the mica plate is gradually increased along with the increase of the modified mica powder, and when the modified mica powder is increased to 22 parts, the content of the modified mica powder is increased again, the variation of the electrical strength is small, and the bending strength is low, so that the optimal modified mica powder is 22 parts. The content of the modified mica is moderate between 18 and 26, and when the unmodified mica powder is adopted, the bonding force in an adhesive system is poor, and the electrical strength and the bending strength are poor.

Similarly, it can be seen from the combination of examples 2, 4 and 5, comparative examples 4 to 6 and table 3 that the modified ceramic powder is preferably 5 parts; as can be seen by combining examples 4, 6 and 7, comparative examples 7 to 9, and table 3, the modified aramid fiber is used in an optimum amount of 4 parts.

It can be seen from a combination of example 1, comparative example 12 and Table 3 that the batch mode of phthalic anhydride, maleic anhydride and phthalic anhydride is significantly better than the single-shot mode. By adopting a one-time feeding mode, the content of the acid anhydride in the previous stage is increased, alcoholysis reaction is carried out, the by-products of the reaction are increased, the reaction is difficult to control, and the modification effect of the adhesive is poor. And through the mode of component feeding, the polyethylene glycol has high content in the initial stage of the reaction, and can react with more epoxy groups, and when the anhydride content in the later stage is high, the polyethylene glycol can react with secondary hydroxyl groups of an epoxy main chain, so that the esterification reaction of the anhydride and the polyethylene glycol and the esterification reaction of the anhydride and the epoxy groups are inhibited, the reaction can be smoothly carried out, the adhesive can be smoothly modified, and the hydrophilicity and the thermal stability of the adhesive are improved.

As can be seen by combining examples 1-9, comparative examples 1-11 and Table 3: by modifying the mica powder, the aramid fiber, the ceramic powder and the adhesive, the electrical strength of the mica composite board is obviously improved compared with that of the mica powder, the aramid fiber, the ceramic powder and the adhesive which are not modified. The mica powder, the aramid fiber and the ceramic powder are modified, and the mica, the aramid fiber and the ceramic with smooth surfaces are endowed with a concave structure, so that a structure similar to mechanical meshing is formed, the specific surface area is increased, the compatibility is increased, and the structural strength is further improved.

It can be seen from the combination of example 1 and comparative example 13 and table 3 that when the mica composite board is laminated by mica paper, the glue content is higher than that of the integrally formed mica composite board, and the bending strength and the dielectric strength are lower than those of the integrally formed mica composite board. The mica composite board is integrally formed, the structure fitting degree with an electric workpiece is high, the electric insulation strength of each point of the mica composite board is kept consistent, no gap is formed, and meanwhile, the mica, the ceramic material and the aramid fiber are filled in the gap, so that the insulation performance and the structural strength are improved. Meanwhile, the process of integral forming is adopted, so that the special-shaped mica plate is convenient to prepare, the preparation process does not need splicing by using an adhesive, the preparation process is simple, and the forming is easy.

To sum up, the best embodiment of the present application is embodiment 6, in embodiment 6, the modified mica powder is 22 parts, the modified ceramic powder is 5 parts, and the modified aramid fiber is 4 parts, and the mica composite material is integrally formed, and the special-shaped mica composite material prepared in embodiment 6 has high electrical strength and excellent bending strength, can be applied to the field of special-shaped workpieces of electrical equipment, and can achieve a good insulating coating effect.

The present embodiment is only for explaining the present application, and it is not limited to the present application, and those skilled in the art can make modifications of the present embodiment without inventive contribution as needed after reading the present specification, but all of them are protected by patent law within the scope of the claims of the present application.

Claims

1. The mica composite material with the internally-added short fibers for the new energy automobile is characterized by being prepared from the following raw materials in parts by weight: 18-26 parts of modified mica powder, 6-12 parts of adhesive, 2-8 parts of modified ceramic powder and 3-5 parts of modified aramid fiber, wherein the surface of the modified mica powder is provided with concave-convex parts, and the surfaces of the modified ceramic powder and the modified aramid fiber are both provided with concave parts;

the modified aramid fiber is prepared from the following raw materials in parts by weight: 6-10 parts of aramid fiber, 1-2 parts of sodium hydroxide, 0.3-0.8 part of polyoxyethylene and 0.2-0.4 part of sodium dodecyl benzene sulfonate; wherein the length of the aramid fiber is 3-10 mm; the modified aramid fiber is prepared by the following method: putting aramid fiber into a sodium hydroxide solution, adding sodium dodecyl benzene sulfonate and polyoxyethylene, uniformly stirring, reacting for 20-30min, taking out, and drying;

The modified mica powder is prepared from the following raw materials in parts by weight: 1-3 parts of tris (hydroxymethyl) aminomethane hydrochloride, 0.2-0.6 part of sodium hydroxide, 0.5-2 parts of dopamine hydrochloride and 22-25 parts of mica powder; the mica powder comprises coarse-fraction mica with the particle size of 250-550 mu m and fine-fraction mica with the particle size of 74-150 mu m, wherein the weight ratio of the coarse-fraction mica to the fine-fraction mica is 1: 3;

the preparation method of the modified mica powder comprises the following steps:

2, preparing a trihydroxymethylaminomethane hydrochloride buffer solution with the pH value of 8.5 by using sodium hydroxide and trihydroxymethylaminomethane hydrochloride, adding dopamine hydrochloride to prepare a dopamine solution, adding coarse-fraction mica and fine-fraction mica into the dopamine solution, stirring for 6-7h, taking out the modified mica, and drying;

the modified ceramic powder is prepared from the following raw materials in parts by weight: 2-4 parts of tert-butyl alcohol, 1-2 parts of acrylamide, 2-4 parts of methylene bisacrylamide, 0.5-1 part of ammonium persulfate, 0.2-0.8 part of tetramethylethylenediamine and 7-16 parts of ceramic powder;

the preparation of the modified ceramic powder comprises the following steps:

c2, adding the ceramic powder into the mixed solution A and uniformly mixing;

c5, crushing the modified ceramic block in the step c4 to 150-200 meshes;

the adhesive comprises a mixed solution B, methylated amino resin and dibenzoyl peroxide, wherein the mixed solution B is prepared from the following raw materials in parts by weight: 8-10 parts of organic silicon epoxy resin, 5-8 parts of polyethylene glycol, 0.6-2 parts of phthalic anhydride, 0.8-3 parts of maleic anhydride, 0.1-0.6 part of dimethylethanolamine and 0.5-0.9 part of diethylene glycol butyl ether;

preparing the mixed solution B, comprising the following steps:

d2, adding the rest of polyethylene glycol, the rest of phthalic anhydride and the rest of maleic anhydride into the step d1, uniformly stirring, controlling the reaction temperature at 140-160 ℃, adding dimethylethanolamine after measuring the acid value of 50mgKOH/g, adjusting the pH to 7-8.5, and stirring to obtain a mixed solution B.

2. The preparation process of the mica composite material with the internally-added short fibers for the new energy automobile as claimed in claim 1 is characterized by comprising the following steps: the method comprises the following steps:

s3, adding dibenzoyl peroxide into the mica slurry obtained in the step S2, and uniformly stirring and dispersing;

s5, compression molding, heating the mold to 40-80 ℃, heating for 4-6h, heating to 150-.

3. The preparation process of the mica composite material of the internal short fiber added for the new energy automobile according to claim 2 is characterized in that: the die in the step S5 includes an upper die and a lower die, the upper die is fixedly connected with a cylinder, a die groove is formed between the upper die and the lower die, the die groove and the mica green body are manufactured in a 1: 1 reshaping effect, a slurry hole for feeding mica slurry is formed in the upper surface of the upper die, and the slurry hole is communicated with the die groove.