阅读说明：本技术 一种耐高温聚砜基复合绝缘纸的制备方法 (Preparation method of high-temperature-resistant polysulfone-based composite insulating paper ) 是由 刘乾坤 于 2019-10-10 设计创作，主要内容包括：本发明涉及一种耐高温聚砜基复合绝缘纸的制备方法,属于绝缘材料技术领域。本发明以聚砜树脂为基材,制备耐高温聚砜基复合绝缘纸,聚砜树脂由于极性较低就能获得优越的热氧稳定性,两个苯环与砜基相邻形成了共轭的二苯酚结构使得分子链具有良好的刚性,聚砜树脂的主链上既不含有影响耐热性的亚异丙基团也不含有能使分子链过分刚性的联苯基团,因此聚砜树脂保留了聚砜类聚合物良好的耐氧性、热稳定性,同时由于主链上的醚键使材料具有了一定的柔性,这样的结构使得聚砜树脂的力学性能优异,刚性大,耐磨,高强度,即使在高温下也保持优良的力学性能,以聚砜树脂为原料制备聚砜基复合绝缘纸可以有效提高绝缘纸的耐高温性和机械强度。(The invention relates to a preparation method of high-temperature-resistant polysulfone-based composite insulating paper, which belongs to the technical field of insulating materials.A polysulfone resin is used as a base material to prepare the high-temperature-resistant polysulfone-based composite insulating paper, the polysulfone resin can obtain excellent thermal oxygen stability due to lower polarity, two benzene rings and sulfone groups are adjacent to each other to form a conjugated diphenol structure, so that a molecular chain has good rigidity, and a main chain of the polysulfone resin does not contain isopropylidene groups which influence heat resistance or biphenyl groups which can cause excessive rigidity of the molecular chain, so that the polysulfone resin keeps good oxygen resistance and thermal stability of polysulfone polymers, and simultaneously, due to ether bonds on the main chain, the material has -determined flexibility, so that the polysulfone resin has excellent mechanical properties, large rigidity, wear resistance and high strength, and can keep excellent mechanical properties even at high temperature, and the high-temperature resistance and the mechanical strength of the insulating paper can be effectively improved by using the polysulfone resin as a raw material to prepare the polysulfone-based composite insulating paper.)

1, A preparation method of high temperature resistant polysulfone-based composite insulating paper, which is characterized in that the preparation method comprises the following steps:

(1) cutting polysulfone fibers and polyester fibers into short fibers of 4-6 cm, adding the short fibers into deionized water, placing the short fibers into a frequency modulation pulping machine, and pulping for 30-40 min at normal temperature to obtain mixed fiber pulp;

(2) adding the modified nano-silica, polyvinyl alcohol, polyacrylamide and polybutadiene latex into the mixed fiber slurry, placing the mixed fiber slurry into a high-shear emulsifying machine, and stirring the mixed fiber slurry at the normal temperature at the rotating speed of 1400-1600 r/min for 20-30 min to obtain papermaking raw stock;

(3) placing the papermaking raw pulp in a paper sample copying device for copying to obtain composite fiber raw paper, adding polysulfone resin into N, N-dimethylacetamide, and stirring at the normal temperature at the rotating speed of 300-350 r/min for 40-60 min to obtain polysulfone resin impregnation liquid;

(4) and (3) soaking the composite fiber base paper in the impregnation liquid for 5-10 min, then drying in an oven at 40-60 ℃ for 30-40 min, and cooling at normal temperature to obtain the high-temperature-resistant polysulfone-based composite insulating paper.

2. The method for preparing high-temperature resistant polysulfone-based composite insulating paper according to claim 1, wherein the polysulfone fiber, the polyester fiber, the polysulfone resin, the modified nano-silica, the polyvinyl alcohol, the polyacrylamide, the polybutadiene latex, the N, N-dimethylacetamide and the deionized water are 40-60 parts by weight of the polysulfone fiber, 12-18 parts by weight of the polyester fiber, 8-12 parts by weight of the polysulfone resin, 2-3 parts by weight of the modified nano-silica, 2-3 parts by weight of the polyvinyl alcohol, 4-6 parts by weight of the polyacrylamide, 20-30 parts by weight of the polybutadiene latex, 16-24 parts by weight of the N, N-dimethylacetamide and 60-90 parts by weight of the deionized water.

3. The preparation method of kinds of high temperature resistant polysulfone-based composite insulating paper according to claim 1, wherein the beating frequency in step (1) is 20-40 Hz.

4. The method for preparing high temperature resistant polysulfone-based composite insulating papers according to claim 1, wherein the polysulfone fiber prepared in step (1) is prepared by the following steps:

(1) adding polysulfone resin into N, N-dimethylformamide, and stirring at the rotating speed of 200-250 r/min for 30-40 min at normal temperature to obtain a polysulfone resin solution;

(2) placing the polysulfone resin solution in an ultrasonic dispersion machine, and ultrasonically shaking for 10-20 min at normal temperature to obtain polysulfone resin spinning solution;

(3) and (3) placing the polysulfone resin spinning solution into an injector of a high-voltage electrostatic spinning device, slowly spraying the polysulfone resin spinning solution onto a collecting roller, and collecting the polysulfone resin spinning solution by rotating the collecting roller at the rotating speed of 60-80 r/min to obtain the polysulfone fiber.

5. The method for preparing kinds of high temperature resistant polysulfone-based composite insulating paper according to claim 4, wherein the polysulfone resin and N, N-dimethylformamide are 20-30 parts by weight of polysulfone resin and 80-120 parts by weight of N, N-dimethylformamide.

6. The method for preparing kinds of high temperature resistant polysulfone-based composite insulating paper according to claim 4, wherein the power of the ultrasonic vibration in step (2) is 300-400W.

7. The method for preparing kinds of high temperature resistant polysulfone-based composite insulating paper according to claim 4, wherein the diameter of the injection needle of the injector in step (3) is 0.1mm, the distance between the injection needle and the collection roller is 12-16 cm, the voltage of electrostatic spinning is 30-40 kV, and the flow rate of polysulfone resin spinning solution is 0.2-0.4 mL/h.

8. The method for preparing kinds of high temperature resistant polysulfone-based composite insulating paper according to claim 1, wherein the specific preparation steps of the modified nano-silica described in step (2) are:

(1) adding stearic acid, methyl triethyl silicane and absolute ethyl alcohol into deionized water, stirring for 20-30 min at the rotating speed of 300-360 r/min under the water bath condition of 30-40 ℃, and preserving heat to obtain a modified solution;

(2) adding nano silicon dioxide into the modification solution, and stirring at the normal temperature at the rotating speed of 600-800 r/min for 40-60 min to obtain a suspension;

(3) placing the suspension in an ultrasonic dispersion machine, and performing ultrasonic dispersion for 30-40 min at normal temperature to obtain dispersion liquid;

(4) and placing the dispersion liquid in a centrifuge, centrifuging and separating at the normal temperature at the rotating speed of 3500-4000 r/min for 20-30 min, taking out the lower layer solid, washing with deionized water for 3-5 times, and placing in an oven at the temperature of 60-80 ℃ for drying for 1-2 h to obtain the modified nano silicon dioxide.

9. The preparation method of high-temperature resistant polysulfone-based composite insulating paper according to claim 8, wherein the weight parts of nano silica, stearic acid, methyl triethyl silane, anhydrous ethanol and deionized water are 20-30 parts of nano silica, 4-6 parts of stearic acid, 8-12 parts of methyl triethyl silane, 20-30 parts of anhydrous ethanol and 80-120 parts of deionized water.

10. The method for preparing kinds of high temperature resistant polysulfone-based composite insulating paper according to claim 8, wherein the power of the ultrasonic dispersion in step (3) is 400-500W.

Technical Field

The invention relates to a preparation method of high-temperature-resistant polysulfone-based composite insulating paper, belonging to the technical field of insulating materials.

Background

The insulating paper is widely used as an insulating material of equipment such as a motor, a cable, a capacitor, a transformer and the like, and is also a main composition material of insulating materials such as a laminated product, a composite material, a prepreg and the like, oil paper composite insulation is an insulation structure commonly used by a large-scale extra-high voltage transformer at present, however, the aging characteristic and the creeping discharge rule of the composite insulation structure under the action of factors such as heat, electricity and the like are not fully known, and the mechanisms such as the volume effect of insulation, the space charge effect of a medium and the like are not deeply researched.

(1) The high temperature resistance is poor, when the running temperature of the transformer exceeds the tolerance temperature of the insulating paper, the insulating paper polymer chain is degraded, the insulating paper becomes fragile, the polymerization degree is reduced, and the insulation aging is accelerated, so that the service life of the transformer is shortened;

(2) in recent years, synthetic polymer insulating materials have the advantages of excellent insulating property, low manufacturing cost, light weight, small size, environmental friendliness and the like, are widely applied to the technical field of electricians, particularly have heat resistance superior to that of electrical paper boards, such as polyimide, polyaramide, polyarylsulfone and polyphenylene sulfide, and are applied to occasions with H-level and higher heat resistance levels.

If the polymer material is used to replace cellulose insulation paper/board, the electric field distribution of the main insulation structure, the longitudinal insulation structure and the end structure in the oil-immersed transformer will change, and the characteristics of the polymer insulation material in oil, such as high temperature resistance, dielectric constant, dielectric loss, oil solubility and tracking resistance, and the like, should be studied. The breakdown voltage is the most direct electrical parameter for characterizing the electrical strength of the insulating material, and the level of the partial discharge starting voltage is an important parameter for characterizing the electrical strength of the insulating material.

As a core device in a power system, a power transformer is in an extremely important position in the power system, and when fails, a large-area power failure accident can be caused, and serious loss is caused to the power system and national economy.

The insulating system of the transformer consisting of insulating paper (board) and insulating oil is affected by factors such as temperature, electric field, moisture, oxygen and the like in the operation process, the insulating system of the oil paper is gradually aged, and the electrical and mechanical properties are reduced, a large number of research results show that the temperature (thermal stress) plays a critical role in the aging of the insulating system of the oil paper, therefore, a large number of scholars at home and abroad carry out related research on the thermal aging mechanism of the oil paper insulation, wherein are researches on chemical parameters and characteristic products in the insulating aging process of the oil paper, such as polymerization degree, furfural, oleic acid value, micro water, dissolved gas in oil and the like, and the deep research on the change rule of the non-electrical parameters plays an important role in disclosing the insulating aging mechanism of the oil paper, and is an electrical characteristic research which mainly focuses on partial discharge, polarization current, dielectric response characteristics, breakdown voltage, dielectric loss, insulation resistance and the like of the oil paper, and the research results of the parameters reflect the change of the electrical properties of the oil paper in the aging process, and the oil paper can directly master the electrical insulation state of the oil paper.

In the aspect of the research on the dielectric breakdown voltage characteristics of the oil paper, the breakdown voltage of cellulose insulation paper (PSP 3010) and NOMEX paper is researched under the three environmental temperatures of 20 ℃, 60 ℃ and 100 ℃ by adopting a mineral oil medium, and the results show that the breakdown voltage of the insulation paper which is impregnated by mixing pure oil, oil and ester does not obviously change along with the increase of the environmental temperature, and the breakdown voltage of the oil-impregnated insulation paper can be improved by adding the ester into the mineral oil.

AnuragJoshi et al tested the AC breakdown voltage of 0.05mm thick TufQUIN insulation paper after heat aging at 27 deg.C and 200 deg.C, 210 deg.C, 220 deg.C, and showed that the breakdown voltage increased with increasing heat aging temperature. However, the TufQUIN insulation paper is only suitable for dry-type transformers, and the article does not give out the change of parameters (such as polymerization degree and the like) reflecting the aging degree of the insulation paper in research, so that the referential of test results is reduced; furthermore, t.k.saha et al believe that the degradation mechanism of cellulosic insulation paper may change when the temperature is above 150 ℃, so that the document chooses temperatures of 200 ℃ and above, which may only be suitable for local ageing.

In general, systematic research on the change of breakdown voltage characteristics in the aging process of the insulation paper is lacked at home and abroad, and steps are needed.

Disclosure of Invention

The invention aims to solve the technical problems that the traditional cellulose insulation paper has poor high-temperature resistance, and when the running temperature of a transformer exceeds the tolerance temperature of the insulation paper, the high-molecular chain of the insulation paper is degraded, the insulation paper becomes fragile, the polymerization degree is reduced, and the insulation aging is accelerated, so that the service life of the transformer is shortened, and provides a preparation method of high-temperature resistant polysulfone-based composite insulation paper.

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

(1) cutting polysulfone fibers and polyester fibers into short fibers of 4-6 cm, adding the short fibers into deionized water, placing the short fibers into a frequency modulation pulping machine, and pulping for 30-40 min at normal temperature to obtain mixed fiber pulp;

(2) adding the modified nano-silica, polyvinyl alcohol, polyacrylamide and polybutadiene latex into the mixed fiber slurry, placing the mixed fiber slurry into a high-shear emulsifying machine, and stirring the mixed fiber slurry at the normal temperature at the rotating speed of 1400-1600 r/min for 20-30 min to obtain papermaking raw stock;

(3) placing the papermaking raw pulp in a paper sample copying device for copying to obtain composite fiber raw paper, adding polysulfone resin into N, N-dimethylacetamide, and stirring at the normal temperature at the rotating speed of 300-350 r/min for 40-60 min to obtain polysulfone resin impregnation liquid;

(4) and (3) soaking the composite fiber base paper in the impregnation liquid for 5-10 min, then drying in an oven at 40-60 ℃ for 30-40 min, and cooling at normal temperature to obtain the high-temperature-resistant polysulfone-based composite insulating paper.

The polysulfone fiber, the polyester fiber, the polysulfone resin, the modified nano-silica, the polyvinyl alcohol, the polyacrylamide, the polybutadiene latex, the N, N-dimethylacetamide and the deionized water are 40-60 parts by weight of the polysulfone fiber, 12-18 parts by weight of the polyester fiber, 8-12 parts by weight of the polysulfone resin, 2-3 parts by weight of the modified nano-silica, 2-3 parts by weight of the polyvinyl alcohol, 4-6 parts by weight of the polyacrylamide, 20-30 parts by weight of the polybutadiene latex, 16-24 parts by weight of the N, N-dimethylacetamide and 60-90 parts by weight of the deionized water.

The beating frequency in the step (1) is 20-40 Hz.

The specific preparation steps of the polysulfone fiber in the step (1) are as follows:

(1) adding polysulfone resin into N, N-dimethylformamide, and stirring at the rotating speed of 200-250 r/min for 30-40 min at normal temperature to obtain a polysulfone resin solution;

(2) placing the polysulfone resin solution in an ultrasonic dispersion machine, and ultrasonically shaking for 10-20 min at normal temperature to obtain polysulfone resin spinning solution;

(3) and (3) placing the polysulfone resin spinning solution into an injector of a high-voltage electrostatic spinning device, slowly spraying the polysulfone resin spinning solution onto a collecting roller, and collecting the polysulfone resin spinning solution by rotating the collecting roller at the rotating speed of 60-80 r/min to obtain the polysulfone fiber.

The weight parts of the polysulfone resin and the N, N-dimethylformamide are 20-30 parts of polysulfone resin and 80-120 parts of N, N-dimethylformamide.

And (3) the power of the ultrasonic oscillation in the step (2) is 300-400W.

The diameter of an injection needle of the injector in the step (3) is 0.1mm, the distance between the injection needle and the collecting roller is 12-16 cm, the voltage of electrostatic spinning is 30-40 kV, and the flow rate of the polysulfone resin spinning solution is 0.2-0.4 mL/h.

The specific preparation steps of the modified nano silicon dioxide in the step (2) are as follows:

(1) adding stearic acid, methyl triethyl silicane and absolute ethyl alcohol into deionized water, stirring for 20-30 min at the rotating speed of 300-360 r/min under the water bath condition of 30-40 ℃, and preserving heat to obtain a modified solution;

(2) adding nano silicon dioxide into the modification solution, and stirring at the normal temperature at the rotating speed of 600-800 r/min for 40-60 min to obtain a suspension;

(3) placing the suspension in an ultrasonic dispersion machine, and performing ultrasonic dispersion for 30-40 min at normal temperature to obtain dispersion liquid;

(4) and placing the dispersion liquid in a centrifuge, centrifuging and separating at the normal temperature at the rotating speed of 3500-4000 r/min for 20-30 min, taking out the lower layer solid, washing with deionized water for 3-5 times, and placing in an oven at the temperature of 60-80 ℃ for drying for 1-2 h to obtain the modified nano silicon dioxide.

The weight parts of the nano silicon dioxide, the stearic acid, the methyl triethyl silicane, the absolute ethyl alcohol and the deionized water are 20-30 parts of the nano silicon dioxide, 4-6 parts of the stearic acid, 8-12 parts of the methyl triethyl silicane, 20-30 parts of the absolute ethyl alcohol and 80-120 parts of the deionized water.

And (4) the power of ultrasonic dispersion in the step (3) is 400-500W.

Compared with other methods, the method has the beneficial technical effects that:

(1) the invention takes polysulfone resin as a base material to prepare high-temperature-resistant polysulfone-based composite insulating paper, the main chain of the polysulfone resin mainly comprises sulfone groups, phenylene groups and ether bonds, the existence of the ether bonds endows the polymer with good flexibility, and the sulfur atom on the sulfone group is in the highest oxidation valence state and has two symmetrical oxygen atoms, so the polysulfone resin can obtain excellent thermal oxygen stability due to lower polarity, two benzene rings and the sulfone groups are adjacent to form a conjugated diphenol structure to ensure that the molecular chain has good rigidity, the main chain of the polysulfone resin does not contain isopropylidene groups which influence the heat resistance and biphenyl groups which can ensure that the molecular chain is excessively rigid, so the polysulfone resin keeps good oxygen resistance and thermal stability of the polysulfone-based polymer, and simultaneously, the ether bonds on the main chain ensure that the material has -determined flexibility, and the structure ensures that the polysulfone resin has excellent mechanical properties, large rigidity, wear resistance and high strength, and excellent mechanical properties even at high temperature can be effectively improved by taking the polysulfone resin as a raw material to prepare the polysulfone-based composite insulating paper.

The invention prepares the high temperature resistant polysulfone-based composite insulating paper by adding the polyester fiber, the modified nano-silica and the polybutadiene latex, the polyester fiber is a synthetic fiber obtained by spinning polyester formed by polycondensation of organic dibasic acid and dihydric alcohol, the crease resistance and the shape retention of the polyester fiber are good, the strength and the elastic recovery capability are higher, the electrical insulating property is good, the electrical insulating property of the insulating paper can be effectively ensured by adding the polyester fiber, the high temperature stability of the insulating paper can be effectively improved by adding the polyester fiber, the high temperature stability is improved, because of the three-dimensional distribution of the monofilament of the polyester fiber, the nano-silica has strong adsorbability, and the polyester fiber can adsorb a great amount of modified nano-silica, so the cohesive force of the polyester fiber and the polysulfone fiber is increased, and simultaneously, because of the criss-cross reinforcement and bridging effect, the flowing property of the polybutadiene latex is reduced, therefore, the high-temperature stability of the insulating paper can be effectively improved, and the stability of the composite fiber insulating paper is greatly improved. After the polyester fibers are added, the fiber monofilaments are uniformly distributed in the papermaking slurry to form a reinforcement effect, so that the strength of the insulating paper can be increased, the fatigue resistance of the insulating paper can be improved, the insulating paper is prevented from being rapidly aged in a high-temperature environment, and the service life of the insulating paper is effectively prolonged.

Detailed Description

Weighing 20-30 parts of polysulfone resin and 80-120 parts of N, N-dimethylformamide respectively, adding the polysulfone resin into the N, N-dimethylformamide, stirring at the rotating speed of 200-250 r/min for 30-40 min at normal temperature to obtain a polysulfone resin solution, placing the polysulfone resin solution into an ultrasonic dispersion machine, ultrasonically oscillating at the power of 300-400W for 10-20 min at normal temperature to obtain a polysulfone resin spinning solution, placing the polysulfone resin spinning solution into an injector of a high-voltage electrostatic spinning device, wherein the diameter of an injection needle is 0.1mm, the distance between the injection needle and a collecting roller is 12-16 cm, spraying the polysulfone resin spinning solution onto the collecting roller at the flow rate of 0.2-0.4 mL/h under the condition of the voltage of 30-40 kV, collecting the collecting roller at the rotating speed of 60-80 r/min to obtain polysulfone fibers, and then weighing the polysulfone fibers in parts by weight, respectively weighing 20-30 parts of nano silicon dioxide, 4-6 parts of stearic acid, 8-12 parts of methyltriethylsilane, 20-30 parts of absolute ethyl alcohol and 80-120 parts of deionized water, adding the stearic acid, the methyltriethylsilane and the absolute ethyl alcohol into the deionized water, stirring for 20-30 min at a rotating speed of 300-360 r/min under a water bath condition of 30-40 ℃, preserving heat to obtain a modified solution, adding the nano silicon dioxide into the modified solution, stirring for 40-60 min at a rotating speed of 600-800 r/min at normal temperature to obtain a suspension, placing the suspension into an ultrasonic dispersion machine, ultrasonically dispersing for 30-40 min at a power of 400-500W at normal temperature to obtain a dispersion solution, placing the dispersion solution into a centrifugal machine, centrifugally separating for 20-30 min at a rotating speed of 3500-4000 r/min at normal temperature, taking a lower-layer solid, washing 3-5 times with the deionized water, placing into an oven at a temperature of 60-80 ℃, drying for 1-2 h, so as to obtain the modified nano silicon dioxide,

respectively weighing 40-60 parts of polysulfone fiber, 12-18 parts of polyester fiber, 8-12 parts of polysulfone resin, 2-3 parts of modified nano-silica, 2-3 parts of polyvinyl alcohol, 4-6 parts of polyacrylamide, 20-30 parts of polybutadiene latex, 16-24 parts of N, N-dimethylacetamide and 60-90 parts of deionized water according to parts by weight, shearing the polysulfone fiber and the polyester fiber into 4-6 cm short fibers, adding the short fibers into deionized water, placing the mixture into a frequency modulation pulping machine, pulping at the normal temperature for 30-40 min at the frequency of 20-40 Hz to obtain mixed fiber pulp, adding the modified nano-silica, the polyvinyl alcohol, the polyacrylamide and the polybutadiene latex into the mixed fiber pulp, placing the mixed fiber pulp into a high-shear emulsifying machine, stirring at the normal temperature for 20-30 min at the rotating speed of 1400-1600 r/min to obtain papermaking virgin pulp, placing the papermaking pulp into a paper sample pulp copying machine for copying, and (3) obtaining composite fiber base paper, adding polysulfone resin into N, N-dimethylacetamide, stirring at the normal temperature at the rotating speed of 300-350 r/min for 40-60 min to obtain polysulfone resin impregnation liquid, soaking the composite fiber base paper in the impregnation liquid for 5-10 min, drying in an oven at the temperature of 40-60 ℃ for 30-40 min, and cooling at the normal temperature to obtain the high-temperature-resistant polysulfone-based composite insulating paper.