Honeycomb dot glue PMP insulating paper and preparation method thereof

Abstract

The application relates to the technical field of insulating paper, and particularly discloses a rhombic dot glue PMP insulating paper and a preparation method thereof. The rhombic dot glue PMP insulating paper comprises a modified cellulose insulating paper base body and a modified epoxy resin. The modified cellulose insulating paper base body is prepared through the following steps: S1, mixing paper pulp and deionized water in a proportion, then putting the mixture into a dissociator, adding 1,3,5-cyclohexane tricarboxylic acid solution, then dissociating to obtain a dissociation solution; S2, mixing the dissociation solution, nano SiC@TiO2 fibers and polymethylpentene fibers, then adding 3-aminopropyl triethoxysilane, then stirring for 30-60 minutes to obtain a cellulose mixed slurry; and S3, adding the cellulose mixed slurry into a paper sheet former, then adding deionized water to mix uniformly, then performing suction filtration and molding on the paper pulp, then performing water absorption setting, and then drying. The modified cellulose insulating paper base body prepared by the application has low dielectric constant and dielectric loss, high volume resistivity, high AC breakdown strength and excellent mechanical performance, and is suitable for preparing the rhombic dot glue PMP insulating paper.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of insulating paper preparation, in particular to a rhombic dot glue PMP insulating paper and a preparation method thereof. BACKGROUND

[0002] Insulating paper is a general term for electrically insulating paper. It is used as an insulating material for cables, coils and other electrical equipment. The existing insulating paper is roughly divided into the following categories: plant fiber insulating paper and synthetic fiber insulating paper. Among them, the plant fiber insulating paper using unbleached kraft pulp of coniferous wood as raw material is widely used due to its low price, but it has problems such as easy aging, low strength, poor electrical performance and the like, which need to be further improved.

[0003] At present, the improvement of the dielectric properties of cellulose insulating paper mainly includes physical modification by blending low dielectric constant polymer powder, polymer fiber or lamellar structure material with cellulose fiber. For example, PB-T insulating paper board prepared by blending polymethylpentene fiber and natural cellulose in Mitsubishi Paper Mills Co., Ltd. of Japan has a dielectric constant of 3.5 and a breakdown voltage increased by 30% compared with traditional insulating paper board gaskets. However, due to the difference in density and hydrophilicity between PMP fiber and natural fiber, PMP fiber cannot be uniformly dispersed in natural fiber during the papermaking process, resulting in high dielectric loss of the finished paper and difficult to meet the requirements of mechanical properties. Another modification method is to directly use low dielectric constant polymers or synthetic fibers to prepare insulating paper to completely replace cellulose insulating paper. A representative is Nomex paper prepared by DuPont Company using synthetic fiber poly-m-phenylene isophthalamide short-cut fiber (aramid 1313, PMTA). Its dielectric constant is only about 3.0, and it has good mechanical properties and thermal stability. However, due to the high cost and technical monopoly, it is currently only used in small areas of equipment hot spots or important parts, and has not been widely promoted. SUMMARY

[0004] In order to further improve the comprehensive performance of cellulose insulating paper, the application provides a rhombic dot glue PMP insulating paper and a preparation method thereof.

[0005] In a first aspect, the application provides a rhombic dot glue PMP insulating paper, which adopts the following technical scheme:

[0006] The rhombic point glue PMP insulating paper comprises a modified cellulose insulating paper base body and a modified epoxy resin, and the modified epoxy resin is located on the upper and lower two sides of the modified cellulose insulating paper base body in a rhombic shape; the modified cellulose insulating paper base body is prepared by the following steps: S1, mixing paper pulp and deionized water in proportion, then putting into a dissolver, while adding 1,3,5-cyclohexane tricarboxylic acid solution, then dissolving 6-8 times, 20 min each time, 18000-21000 revolutions each time, to obtain a dissolving liquid; S2, mixing the dissolving liquid, nano SiC@TiO2 fiber and polymethylpentene fiber, then adding 3-aminopropyl triethoxysilane, then stirring at a speed of 500-800 rpm for 30-60 min to obtain a cellulose mixed slurry; S3, adding the cellulose mixed slurry into the slurry storage chamber of a paper sheet former, then adding deionized water to reach the required scale for papermaking, uniformly mixing, then suction filtering and forming the paper pulp, then absorbing water with a water absorption roller and setting, and finally drying the wet paper in a dryer.

[0007] By adopting the above technical scheme, the Russian coniferous wood fiber is modified by 1,3,5-cyclohexane tricarboxylic acid, and then mixed with polymethylpentene fiber and nano SiC@TiO2 fiber, which can improve the problem of poor density and affinity of polymethylpentene fiber and Russian coniferous wood fiber, make them uniformly dispersed, and increase the stability between the three fibers through 3-aminopropyl triethoxysilane, so as to finally prepare a modified cellulose insulating paper base body with excellent comprehensive performance for rhombic point glue PMP insulating paper.

[0008] Preferably, the mass-volume ratio of the paper pulp, deionized water and 1,3,5-cyclohexane tricarboxylic acid solution in S1 is (3-5) g:(15-20) mL:(1-3) mL.

[0009] By adopting the above technical scheme, the amount of 1,3,5-cyclohexane tricarboxylic acid solution is appropriate, and the prepared dissolving liquid has good affinity with polymethylpentene fiber.

[0010] Preferably, the mass-volume ratio of the dissolving liquid, nano SiC@TiO2 fiber, polymethylpentene fiber and 3-aminopropyl triethoxysilane in S2 is (10-15) mL:(1-1.5) g:(2-3) g:(0.5-1) g.

[0011] By adopting the above technical scheme, the above proportion of raw materials is appropriate, which is conducive to the stability of the cellulose mixed slurry.

[0012] Preferably, the volume ratio of the cellulose mixed slurry and deionized water in S3 is (10-15) mL:(12-17) mL.

[0013] By adopting the technical scheme, the prepared modified cellulose insulation paper base has moderate thickness.

[0014] Preferably, the preparation method of the pulp in S1 is as follows: after cutting the Russian coniferous wood pulp board, 15 times of mass of deionized water is added, and the pulp board is soaked at room temperature for 32 hours, then the soaked pulp board is beaten, the pulp sheet is immersed in deionized water, and the pulp sheet is defibrated for 15 minutes, then 5 kg of weight is added for further beating, and the beating degree is tested to 85°SR at the same time, after the beating is completed, the cellulose slurry obtained after beating is filtered and dried in a vacuum drying box for 24 hours to obtain dried pulp.

[0015] By adopting the technical scheme, the fiber bundles of the Russian coniferous wood pulp board are separated.

[0016] Preferably, the preparation method of the poly-methyl-pentene fiber is as follows: PMP resin particles are added to a screw extruder, heated to 270 DEG C, and the PMP resin is uniformly heated, melted and plasticized; the melted PMP is extruded through a spinneret in a tubular liquid stream, and is stretched by a stretching device at a speed of 500 m / min at a position 7 meters below the spinneret under the cooling and solidification of the surrounding air to obtain poly-methyl-pentene fiber.

[0017] By adopting the technical scheme, the prepared poly-methyl-pentene fiber has moderate diameter and hollow structure, and the dielectric constant is reduced.

[0018] Preferably, the 1,3,5-cyclohexane tricarboxylic acid solution is composed of 1g of 1,3,5-cyclohexane tricarboxylic acid, 1g of sodium hypophosphite and 25mL of deionized water, and is uniformly mixed by ultrasonic.

[0019] By adopting the technical scheme, the proportion of each component is moderate, which is beneficial to the esterification of 1,3,5-cyclohexane tricarboxylic acid and pulp cellulose.

[0020] Preferably, the preparation method of the nano SiC@TiO2 fiber comprises the following steps: 2.5g of polycarbosilane is dissolved in 4mL of dimethylbenzene, ultrasonic dispersion is performed for 2.5h to obtain polycarbosilane spinning solution; the polycarbosilane spinning solution is electrospun to obtain polycarbosilane fiber; then 10mL of titanium tetrabutoxide solution with a concentration of 0.05g / mL is added dropwise to 5g of polycarbosilane fiber, and the mixture is incubated at 220 DEG C for 13h, then the lower precipitate is collected, washed with ethanol by centrifugation for 3 times, then pre-oxidized at 200 DEG C for 3h in an air atmosphere, and then incubated at 1250 DEG C for 3h to obtain nano SiC@TiO2 fiber.

[0021] By adopting the technical scheme, the nano TiO2 is loaded on the SiC fiber to prepare the nano SiC@TiO2 fiber. On the one hand, the nano TiO2 loaded on the SiC fiber can obtain nano TiO2 particles with smaller particle size, so as to improve the AC breakdown strength of the modified cellulose insulation paper base. On the other hand, the SiC fiber is mixed with the polymethylpentene fiber and the Russian needle leaf fiber, so that the nano TiO2 particles are more uniformly dispersed, and the dielectric constant and the dielectric loss are effectively reduced.

[0022] In a second aspect, the application provides a preparation method of the diamond lattice point gluing PMP insulation paper, which comprises the following steps: applying the modified epoxy resin on a diamond lattice impregnation roller, and then applying the modified epoxy resin on the upper and lower surfaces of the modified cellulose insulation paper base by using the impregnation roller; and drying the modified cellulose insulation paper base after impregnation in a drying oven to obtain the diamond lattice point gluing PMP insulation paper.

[0023] In summary, the application has the following beneficial effects:

[0024] 1. In the application, the Russian needle leaf fiber is modified by using 1,3,5-cyclohexane tricarboxylic acid, and then mixed with the polymethylpentene fiber and the nano SiC@TiO2 fiber. The density and the affinity of the polymethylpentene fiber and the Russian needle leaf fiber can be improved, the three fibers are uniformly dispersed, the stability between the three fibers is increased by using 3-aminopropyl triethoxysilane, and finally the modified cellulose insulation paper base with excellent comprehensive performance is prepared, which is used for the diamond lattice point gluing PMP insulation paper.

[0025] 2. In the application, the nano TiO2 is loaded on the SiC fiber to prepare the nano SiC@TiO2 fiber, which is used for preparing the modified cellulose insulation paper base. On the one hand, the nano TiO2 loaded on the SiC fiber can obtain nano TiO2 particles with smaller particle size, so as to improve the AC breakdown strength of the modified cellulose insulation paper base. On the other hand, the SiC fiber is mixed with the polymethylpentene fiber and the Russian needle leaf fiber, so that the nano TiO2 particles are more uniformly dispersed, and the dielectric constant and the dielectric loss are effectively reduced.

[0026] 3. The modified cellulose insulation paper base prepared by the preparation method of the application has the characteristics of low dielectric constant and dielectric loss, high volume resistivity, high AC breakdown strength and excellent mechanical properties, and is suitable for preparing the diamond lattice point gluing PMP insulation paper. DETAILED DESCRIPTION

[0027] The application will be further described in detail in combination with the examples.

[0028] The raw materials of the examples and the comparative examples of the application are all ordinary commercial products, except for special instructions.

[0029] Embodiment

[0030] Embodiment 1

[0031] A diamond dot glue PMP insulating paper, comprising a modified cellulose insulating paper base body and a modified epoxy resin, the modified epoxy resin is located on the upper and lower two sides of the modified cellulose insulating paper base body in a diamond shape; the modified cellulose insulating paper base body is prepared by the following steps: S1, 3g of pulp and 15mL of deionized water are mixed in proportion, then put into a dissolver, while adding 1mL of 1,3,5-cyclohexane tricarboxylic acid solution, then dissolving 6 times, 20min interval each time, 18000 revolutions each time, to get a dissolving solution; S2, 10mL of dissolving solution, 1g of nano SiC@TiO2 fiber, 2g of polymethylpentene fiber are mixed, then 0.5g of 3-aminopropyl triethoxysilane is added, then stirred at a speed of 500rpm for 30min, to get a cellulose mixed slurry; S3, 10mL of cellulose mixed slurry is added to the stock tank of a paper sheet former, then 17mL of deionized water is added to reach the required scale for papermaking, after uniform mixing, the pulp is suction filtered and formed, then the water is absorbed by the water absorption roller and the wet paper is shaped, finally the wet paper is dried in a dryer.

[0032] The preparation method of the pulp in S1 is as follows: after cutting the Russian coniferous wood pulp board (about 1cm×1cm), 15 times the mass of deionized water is added, soaked at room temperature for 32h, then the soaked pulp board is beaten, the pulp sheet is immersed in deionized water, and the pulp sheet is defibrated for 15min, then 5kg of weight is added for further beating, and the beating degree is tested to 85°SR at the same time, after beating, the cellulose slurry obtained after beating is filtered and dried in a vacuum drying box for 24h to obtain dried pulp.

[0033] The preparation method of the polymethylpentene fiber is as follows: PMP resin particles are added to a screw extruder, heated to 270℃, and the PMP resin is uniformly heated, melted and plasticized; the melted PMP is extruded through a spinneret in a tubular liquid stream, and is stretched by a stretching device at a speed of 500m / min under the spinneret after being cooled and solidified by the surrounding air, to obtain a polymethylpentene fiber with a diameter of 220 microns.

[0034] The 1,3,5-cyclohexane tricarboxylic acid solution is composed of 1,3,5-cyclohexane tricarboxylic acid, sodium hypophosphite and deionized water in a ratio of 1g:1g:25mL, and is uniformly mixed by ultrasonic.

[0035] The preparation method of the nano SiC@TiO2 fiber comprises the following steps: 2.5 g of polycarbosilane is dissolved in 4 mL of dimethylbenzene, ultrasonic dispersion is carried out for 2.5 h to obtain a polycarbosilane spinning solution; the polycarbosilane spinning solution is electrospun (3 mL of the polycarbosilane spinning solution is sucked by a syringe, a needle with an inner diameter of 0.5 mm is adopted, a voltage of 20 kV, a fiber collection distance of 12 cm and a feeding rate of 18 μL / min are selected), and polycarbosilane fiber is obtained; then 10 mL of a titanium tetrabutoxide solution with a concentration of 0.05 g / mL is added dropwise to 5 g of the polycarbosilane fiber, the mixture is kept at 220 ℃ for 13 h, then the lower precipitate is collected, washed by centrifugation with ethanol for 3 times, then pre-oxidized at 200 ℃ for 3 h in an air atmosphere, and then kept at 1250 ℃ for 3 h, and finally the nano SiC@TiO2 fiber with a diameter of 350 microns is obtained; the structure of the nano SiC@TiO2 fiber is that TiO2 nanorods are loaded on the SiC fiber, and the diameter of the TiO2 nanorod is 210 nanometers.

[0036] Example 2

[0037] A diamond dot glue PMP insulating paper, comprising a modified cellulose insulating paper base body and a modified epoxy resin, the modified epoxy resin is located on the upper and lower two sides of the modified cellulose insulating paper base body in a diamond shape; the modified cellulose insulating paper base body is prepared by the following steps: S1, 4 g of paper pulp and 18 mL of deionized water are mixed in proportion, then put into a dissociator, at the same time, 2 mL of 1,3,5-cyclohexane tricarboxylic acid solution is added, then dissociated for 7 times, each time interval is 20 min, each time is 20000 revolutions, and a dissociation solution is obtained; S2, 13 mL of the dissociation solution, 1.3 g of nano SiC@TiO2 fiber and 2.5 g of polymethylpentene fiber are mixed, then 0.8 g of 3-aminopropyl triethoxysilane is added, then stirred at a speed of 700 rpm for 45 min, and a cellulose mixed slurry is obtained; S3, 13 mL of the cellulose mixed slurry is added to the stock tank of a paper sheet former, then 14 mL of deionized water is added to reach the required scale for papermaking, after uniform mixing, the paper pulp is suction filtered and formed, then the water is absorbed by a water absorption cylinder and shaped, and finally the wet paper is dried in a dryer.

[0038] The preparation method of the paper pulp, the polymethylpentene fiber and the nano SiC@TiO2 fiber is as shown in the example 1.

[0039] Example 3

[0040] A diamond point glue PMP insulating paper, comprising a modified cellulose insulating paper base body and a modified epoxy resin, the modified epoxy resin is located on the upper and lower two sides of the modified cellulose insulating paper base body in a diamond shape; the modified cellulose insulating paper base body is prepared by the following steps: S1, 5g of paper pulp and 20mL of deionized water are mixed in proportion, then put into a dissociator, while adding 3mL of 1,3,5-cyclohexane tricarboxylic acid solution, then dissociating 8 times, 21000 revolutions each time, 20min interval each time, to obtain a dissociation solution; S2, 15mL of the dissociation solution, 1.5g of nano SiC@TiO2 fiber, 3g of polymethylpentene fiber are mixed, then 1g of 3-aminopropyl triethoxysilane is added, then stirred at a speed of 800rpm for 60min, to obtain a cellulose mixed slurry; S3, 15mL of the cellulose mixed slurry is added to the stock tank of a paper sheet former, then 12mL of deionized water is added to reach the required scale for papermaking, after uniform mixing, the paper pulp is suction filtered and formed, then the water is absorbed by a water absorption roller and the wet paper is shaped, finally the wet paper is dried in a dryer.

[0041] The preparation method of the paper pulp, the polymethylpentene fiber and the nano SiC@TiO2 fiber is as shown in Embodiment 1.

[0042] A preparation method of a diamond point glue PMP insulating paper, comprising the following steps: applying a modified epoxy resin on a diamond-shaped glue dipping roller, then applying the modified epoxy resin on the upper and lower two surfaces of a modified cellulose insulating paper base body by using the glue dipping roller, and then drying the modified cellulose insulating paper base body after glue dipping in a drying oven, to obtain the diamond point glue PMP insulating paper.

[0043] The modified epoxy resin can be tetrahydrophthalic acid diglycidyl ester or hexahydrophthalic acid diglycidyl ester.

[0044] Comparative Example

[0045] Comparative Example 1

[0046] The same as Embodiment 2, except that the same mass of "nano TiO2" is used instead of "nano SiC@TiO2 fiber".

[0047] Comparative Example 2

[0048] The same as Embodiment 2, except that "1,3,5-cyclohexane tricarboxylic acid solution" is not added.

[0049] Comparative Example 3

[0050] The same as Embodiment 2, except that "polymethylpentene fiber" is not added.

[0051] Comparative Example 4

[0052] The following method is used to prepare the cellulose insulation paper matrix: S1, 4 g of paper pulp and 18 mL of deionized water are mixed in proportion, then put into a dissolver, then dissolved for 6-8 times, 20 min interval each time, 18000-21000 revolutions each time, to obtain a dissolved solution; S2, 13 mL of the dissolved solution is added to the stock chest of the paper sheet former, then 14 mL of deionized water is added to reach the required scale for papermaking, after uniform mixing, the pulp is suction filtered and formed, then the water is absorbed by the water absorption cylinder and the wet paper is shaped, finally the wet paper is dried in a dryer.

[0053] Performance test

[0054] The dielectric constant and dielectric loss of the modified cellulose insulation paper matrix prepared in Examples 1-3 and Comparative Examples 1-3 and the cellulose insulation paper matrix prepared in Comparative Example 4 are determined according to IEC 60250:1969, the dielectric constant and dielectric loss thereof at 50 Hz are recorded, and the results are shown in Table 1;

[0055] Table 1. Dielectric constant and dielectric loss at 50 Hz

[0056] Dielectric constant Dielectric loss / % Example 1 3.12 0.00367 Example 2 3.08 0.00342 Example 3 3.11 0.00355 Comparative Example 1 3.32 0.00506 Comparative Example 2 3.46 0.00412 Comparative Example 3 3.42 0.00434 Comparative Example 4 3.90 0.00540

[0057] As can be seen from Table 1, the modified cellulose insulation paper matrix prepared in Examples 1-3 has excellent dielectric constant and dielectric loss, the dielectric constant is as low as 3.08, and the dielectric loss is as low as 0.00367%; in combination with Comparative Examples 1-4, it can be seen that the nano-SiC@TiO2 fiber, 1,3,5-cyclohexane tricarboxylic acid solution and polymethylpentene fiber have certain influence on the dielectric constant and dielectric loss of the modified cellulose insulation paper matrix, the 1,3,5-cyclohexane tricarboxylic acid solution has greater influence on the dielectric constant, and the addition of nano-SiC@TiO2 fiber can further reduce the dielectric loss.

[0058] The AC breakdown strength of the modified cellulose insulation paper matrix prepared in Examples 1-3 and Comparative Examples 1-3 and the cellulose insulation paper matrix prepared in Comparative Example 4 is determined according to IEC 60243-1:2013;

[0059] The volume resistivity of the modified cellulose insulation paper matrix prepared in Examples 1-3 and Comparative Examples 1-3 and the cellulose insulation paper matrix prepared in Comparative Example 4 is determined according to IEC 60093:1980;

[0060] The results are shown in Table 2;

[0061] Table 2. AC breakdown strength and volume resistivity of the modified cellulose insulation paper matrix

[0062] AC breakdown strength (kV / mm) Volume resistivity (10 4 Ω-cm) Example 1 81.5 77.3 Example 2 82.2 77.1 Example 3 81.7 76.3 Comparative Example 1 77.3 74.8 Comparative Example 2 77.0 72.7 Comparative Example 3 78.4 75.3 Comparative Example 4 76.6 71.5

[0063] As can be seen from Table 2, the modified cellulose insulation paper matrix prepared in Examples 1-3 has strong AC breakdown strength and large volume resistivity, the AC breakdown strength is as high as 82.2 kV / mm, and the volume resistivity is as high as 77.310 4 Ω·cm; as can be seen from Comparative Examples 1-4, the nano-SiC@TiO2 fiber, the 1,3,5-cyclohexane tricarboxylic acid solution and the polymethylpentene fiber all have certain influences on the AC breakdown strength and the volume resistivity of the modified cellulose insulation paper matrix, the greatest influence is the nano-SiC@TiO2 fiber, the second is the 1,3,5-cyclohexane tricarboxylic acid solution, and the last is the polymethylpentene fiber.

[0064] The tensile strength and the elongation at break of the modified cellulose insulation paper matrix prepared in Examples 1-3 and Comparative Examples 1-3 and the cellulose insulation paper matrix prepared in Comparative Example 4 were determined according to ISO 1924 / 3:2005. The results are shown in Table 3.

[0065] Table 3. Mechanical properties of the modified cellulose insulation paper matrix

[0066] Tensile strength (kN / m) Elongation at break (%) Example 1 11.5 3.22 Example 2 12.3 3.35 Example 3 11.7 3.28 Comparative Example 1 9.98 3.08 Comparative Example 2 10.13 2.83 Comparative Example 3 10.45 3.02 Comparative Example 4 9.15 2.63

[0067] As can be seen from Table 3, the modified cellulose insulation paper matrix prepared in Examples 1-3 has good mechanical properties, the tensile strength is as high as 11.5 kN / m, and the elongation at break is as high as 3.35%; as can be seen from Comparative Examples 1-4, the nano-SiC@TiO2 fiber, the 1,3,5-cyclohexane tricarboxylic acid solution and the polymethylpentene fiber all have certain influences on the tensile strength and the elongation at break of the modified cellulose insulation paper matrix, among them, the nano-SiC@TiO2 fiber has greater influence on the tensile strength of the modified cellulose insulation paper matrix, and the 1,3,5-cyclohexane tricarboxylic acid has greater influence on the elongation at break of the modified cellulose insulation paper matrix.

[0068] The specific embodiments are only an explanation of the present application, and are not a limitation of the present application, and those skilled in the art can make modifications to the embodiments without creative contribution after reading the specification, and the modifications are protected by the patent law as long as they are within the scope claimed by the present application.

Claims

1. A diamond-patterned PMP insulating paper, characterized in that, The invention comprises a modified cellulose insulating paper matrix and a modified epoxy resin, wherein the modified epoxy resin is arranged in a rhombic pattern on the upper and lower surfaces of the modified cellulose insulating paper matrix. The modified cellulose insulating paper matrix is ​​prepared by the following steps: S1, pulp and deionized water are mixed in a certain proportion and then placed in a dissociator, while 1,3,5-cyclohexanetricarboxylic acid solution is added. The mixture is then dissociated 6-8 times, with an interval of 20 minutes between each dissociation, at 18,000-21,000 rpm each time, to obtain a dissociated liquid; S2, the dissociated liquid, nano-SiC@TiO2 fibers, and polymethylpentene fibers are mixed, and then 3-aminopropyltriethoxysilane is added. The mixture is then stirred at a rate of 500-800 rpm for 30-60 minutes to obtain a cellulose mixed slurry; S3, the cellulose mixed slurry is added to the storage chamber of a paper forming machine, and then deionized water is added to reach the required scale for papermaking. After uniform mixing, the pulp is filtered and formed, then the water is absorbed and shaped by a water-absorbing roller, and finally the wet paper is placed in a dryer for drying. The mass-to-volume ratio of pulp, deionized water, and 1,3,5-cyclohexanetricarboxylic acid solution in S1 is (3-5) g:(15-20) mL:(1-3) mL; the 1,3,5-cyclohexanetricarboxylic acid solution is composed of 1,3,5-cyclohexanetricarboxylic acid, sodium hypophosphite, and deionized water in a ratio of 1 g:1 g:25 mL. The preparation method of the nano-SiC@TiO2 fiber includes the following steps: 2.5g of polycarbosilane is dissolved in 4mL of xylene and ultrasonically dispersed for 2.5h to obtain a polycarbosilane spinning solution; the polycarbosilane spinning solution is electrospun to obtain polycarbosilane fiber; then 10mL of tetrabutyl titanate solution with a concentration of 0.05g / mL is added dropwise to 5g of polycarbosilane fiber, and the mixture is kept at 220℃ for 13h. The lower precipitate is then collected and washed three times by centrifugation with ethanol. The mixture is then pre-oxidized at 200℃ for 3h in air atmosphere and then kept at 1250℃ for 3h to obtain the final product. The preparation method of the polymethylpentene fiber is as follows: PMP resin granules are added to a screw extruder and heated to 270°C to make the PMP resin melt and plasticize uniformly; the molten PMP is extruded through a spinneret in a tubular liquid stream, and after being cooled and solidified by the surrounding air and stretched by a winding device at a speed of 500 m / min 7 meters below the spinneret, polymethylpentene fiber is obtained. The preparation method of pulp in S1 is as follows: After cutting Russian softwood pulp board, add 15 times the mass of deionized water and soak at room temperature for 32 hours. Then, beat the soaked pulp board, add deionized water to submerge the pulp sheet, loosen for 15 minutes, and then increase the load by 5 kg to continue beating. At the same time, test the freeness to 85°SR. After beating, filter the cellulose pulp obtained after beating thoroughly and put it into a vacuum drying oven to dry for 24 hours to obtain dried pulp.

2. The diamond-patterned PMP insulating paper according to claim 1, characterized in that, The mass-to-volume ratio of the dissociation liquid, nano-SiC@TiO2 fiber, polymethylpentene fiber, and 3-aminopropyltriethoxysilane in S2 is (10-15) mL:(1-1.5) g:(2-3) g:(0.5-1) g.

3. The diamond-patterned PMP insulating paper according to claim 1, characterized in that, The volume ratio of cellulose mixed slurry to deionized water in S3 is (10-15) mL: (12-17) mL.

4. A method for preparing diamond-patterned PMP insulating paper, characterized in that, Includes the following steps: The modified epoxy resin is applied to a diamond-shaped impregnation roller, and then applied to the upper and lower surfaces of the modified cellulose insulating paper substrate as described in any one of claims 1-3. The impregnated modified cellulose insulating paper substrate is placed in a drying oven for drying to obtain diamond-shaped glued PMP insulating paper.