Oil-resistant hydrolysis-resistant electrical insulation composite material as well as preparation method and application thereof

Abstract

The invention relates to the technical field of electrical insulation materials, in particular to an oil-resistant hydrolysis-resistant electrical insulation composite material and a preparation method and application thereof.The composite material comprises a membrane material, paper materials adhered to the two sides of the membrane material and glue playing a bonding role, paper pulp for preparing the paper material comprises polyphenylene sulfide staple fibers, meta-aramid staple fibers and meta-aramid precipitation pulp. The polyphenylene sulfide is prepared by polymerization reaction of anhydrous sodium sulfide and dichlorobenzene, the molar ratio of the anhydrous sodium sulfide to the dichlorobenzene is 1: (0.95-0.98), the dichlorobenzene comprises m-dichlorobenzene and p-dichlorobenzene, and the molar ratio of the m-dichlorobenzene to the p-dichlorobenzene is (3-4): 1. The oil-resistant and hydrolysis-resistant electrical insulation composite material disclosed by the invention has good mechanical properties and electrical properties, can meet the application requirements in a motor, has good insulation properties, and has oil-resistant and hydrolysis-resistant properties at the same time.

Description

Technical Field

[0001] The invention relates to an oil-resistant and hydrolysis-resistant electrical insulating composite material and a preparation method and application thereof, belonging to the technical field of electrical insulating materials. Background Art

[0002] With the continuous development of society, the promotion of national policies and the enhancement of people's environmental awareness, the popularity of new energy vehicles is gradually deepening. This is also inseparable from the development of new energy vehicle heat dissipation technology. As the drive of pure electric new energy vehicles, the motor can achieve extremely low emissions or zero emissions. In the process of driving and recovering energy in pure electric vehicles, the stator core and stator winding of the motor will generate losses during the movement, and these losses will dissipate outward in the form of heat. Therefore, effective cooling media and cooling methods are needed to take away the heat to ensure that the motor can operate safely and reliably in a stable ventilation system with balanced cold and hot cycles.

[0003] High temperature conditions have a negative impact on motor efficiency and battery safety, so excellent heat dissipation methods are the focus of future electric drive system development. The heat dissipation units of new energy vehicles mainly include power batteries, drive motors and electronic control systems. From the perspective of traditional engine heat dissipation technology and the actual application of new energy vehicle heat dissipation, water cooling and air cooling are currently the two main methods of heat dissipation for new energy vehicles.

[0004] Oil-cooled motors have advantages over water-cooled motors, such as direct contact, large contact area, and corrosion resistance. At present, the common cooling methods for motors are air cooling, liquid cooling, and evaporative cooling. Air cooling has low cost and strong reliability, but poor heat dissipation performance, and is mainly used in small-power motors; evaporative cooling uses gas-liquid phase change cycles to achieve efficient cooling of motors, and is mainly used in super-large mechanical equipment, but is not suitable for automotive heat dissipation.

[0005] Oil-cooled motors have the following advantages: 1) Oil is neither magnetic nor conductive, and can directly contact the windings and take away the generated heat. However, water directly contacting the motor may cause a short circuit, so it can only take away heat by flowing through specific pipes, which is less efficient. 2) Compared with oil, water is more likely to contain impurities or corrosive substances. Long-term use will not only corrode the system, but also produce scale in the channels, shortening the service life of the motor. In the future, oil cooling of drive motors will gradually replace water cooling, and both cooling efficiency and safety factor will increase. Drive motors are currently developing towards high speed and high torque, but considering the trend of integration, the internal space of the motor tends to be compact, and the heat generated during operation doubles. In addition, the heat dissipation space is sharply reduced, which poses a greater challenge to the cooling capacity of the system due to the heat generated by the stator windings and magnetic steel.

[0006] Oil cooling is to directly spray ATF oil on the end of the motor winding to dissipate heat. The insulating material is in direct contact with the ATF oil and the ATF oil also contains a small amount of water (generally the water content is below 5000ppm). To a certain extent, the presence of water will decompose the insulating material. The existing insulating materials have poor oil resistance and have been subjected to ATF oil corrosion and hydrolysis for a long time, which greatly reduces the material performance, especially the electrical insulation performance, which seriously affects the reliability of oil-cooled motors. Therefore, the development of oil-cooled motors has higher requirements for the insulating materials inside the motors, requiring the insulating materials to have both oil corrosion resistance and hydrolysis resistance.

[0007] At present, most of the electrical insulation composite materials used in domestic oil-cooled motors rely on imported raw materials for production and preparation, and the price of imported raw materials is high. However, the imported electrical insulation composite materials are immersed in the oil-water mixture of 99.5vol% ATF oil and 0.2vol% pure water in the sealed tank (the liquid level of the "oil-water mixture" is 75% of the container depth) and the samples are all immersed in the "oil-water mixture" for high and low temperature (155℃ / 40h~-45℃ / 8h as a cycle) cycle, and the switching time is less than 5min (two-box method, sample conversion outside the box). After 8 cycles of high and low temperature cycle, the substrate is easy to fall off during the winding process, and the service life of the electrical insulation material is seriously reduced. Therefore, when it is used in the oil-cooled motor of electric vehicles with direct spraying technology, its winding and corona resistance life performance still needs to be improved.

[0008] Therefore, there is an urgent need to develop a composite material that is resistant to ATF oil, hydrolysis, and has excellent electrical insulation properties to meet the technical needs of the development of oil-cooled motors. Summary of the invention

[0009] In view of the deficiencies in the prior art, the present invention provides an oil-resistant and hydrolysis-resistant electrical insulating composite material and a preparation method and application thereof. The composite material meets the strength performance requirements of application in motors and has good oil corrosion resistance and hydrolysis resistance.

[0010] The technical solution of the present invention to solve the above technical problems is as follows: an oil-resistant and hydrolysis-resistant electrical insulating composite material, the composite material includes a membrane material and paper materials adhered to both sides of the membrane material and glue for bonding, the membrane material is made of polyphenylene sulfide, and the pulp for preparing the paper material includes polyphenylene sulfide staple fibers, meta-aramid staple fibers and meta-aramid precipitation slurry.

[0011] Furthermore, the polyphenylene sulfide is prepared by polymerization reaction of anhydrous sodium sulfide and dichlorobenzene, the molar ratio of the anhydrous sodium sulfide to dichlorobenzene is 1:(0.95-0.98), the dichlorobenzene includes meta-dichlorobenzene and para-dichlorobenzene, and the molar ratio of meta-dichlorobenzene to para-dichlorobenzene is (3-4):1.

[0012] Furthermore, in the pulp, the mass ratio of the polyphenylene sulfide staple fibers, meta-aramid staple fibers and meta-aramid precipitation slurry is (3-4): (2-3): (3-5).

[0013] Furthermore, the length of the polyphenylene sulfide staple fiber is 9-20 mm; the length of the meta-aramid staple fiber is 9-20 mm; the solid content of the meta-aramid fibrils in the meta-aramid precipitation slurry is 4-7%, the average length of the meta-aramid fibrils is 0.6-1.8 mm, and the specific surface area of ​​the meta-aramid fibrils is 25-55 m 2 / g.

[0014] The present invention also discloses a method for preparing an oil-resistant and hydrolysis-resistant electrical insulating composite material, the preparation method comprising: S1. Preparation of polyphenylene sulfide pellets: Under inert gas conditions, dichlorobenzene and anhydrous sodium sulfide are dissolved in a polar solvent, and a polymerization reaction is carried out under the action of an alkali metal salt, and after the reaction is completed, polyphenylene sulfide pellets are obtained through post-treatment; S2. Preparation of film and paper materials: Film preparation: After the polyphenylene sulfide pellets are melt-extruded into sheets, they are bidirectionally drawn and rolled to obtain film materials; Paper material preparation: polyphenylene sulfide pellets are melted into filaments to obtain polyphenylene sulfide staple fibers, and polyphenylene sulfide staple fibers, meta-aramid staple fibers and meta-aramid precipitated slurry are mixed and then papered to obtain paper material; S3. Preparation of composite materials: Glue is applied on both sides of the membrane material, and after drying, it is pressed with paper material and cured to obtain a composite material.

[0015] Furthermore, in step S1, the polymerization reaction temperature is 180-270° C., the reaction pressure is 0-2 MPa, and the reaction time is 1-2 h.

[0016] Furthermore, the process of preparing the membrane material in step S2 is as follows: The dried polyphenylene sulfide pellets are melted at high temperature and then extruded through a twin-screw extruder through a die to form a sheet, which is then bidirectionally drawn and rolled to obtain a film material; The high temperature melting temperature is 270-320°C, and the extrusion pressure is 3.0-9.0MPa; The die is a slit extrusion die, the die insulation time is 4-10h, and the die temperature is 100-180°C; The drawing temperature is 130-270°C, the transverse drawing ratio is 1:(2-2.5), and the longitudinal drawing ratio is 1:(3-5).

[0017] Furthermore, the process of preparing the paper material in step S2 is as follows: First, the meta-aramid precipitated slurry is beaten and dispersed, and the polyphenylene sulfide staple fiber and the meta-aramid staple fiber are debonded and dispersed to obtain debonded mixed fibers, and then the precipitated slurry after beating and dispersion and the debonded mixed fibers are stirred and blended uniformly to obtain mixed pulp, and the mixed pulp is subjected to flow forming, pressing and drying, hot pressing forming, and rewinding and slitting to obtain paper material; The pressure of the pressing and drying is 1-3 MPa, and the temperature of the pressing and drying is 130-170°C; The pressure of the hot pressing molding is 20-30 MPa, and the temperature of the hot pressing molding is 230-270°C.

[0018] Furthermore, in step S3, the amount of glue applied on one side of the film is 5-50 g / m 2 The drying temperature is 50-150℃, the pressure during pressing is 0.3-0.6Mpa, and the pressing temperature is 35-70℃.

[0019] The invention also discloses an application of an oil-resistant and hydrolysis-resistant electrical insulation composite material, wherein the composite material is applied in a motor.

[0020] The beneficial effects of the present invention are: The strength performance of the oil-resistant and hydrolysis-resistant electrical insulation composite material of the present invention meets the application requirements in the motor, and the composite material has good insulation performance, and has oil resistance and hydrolysis resistance. The oil-resistant and hydrolysis-resistant electrical insulation composite material of the present invention can effectively extend the service life of the insulation material, improve the safety performance of the motor, and then improve the safety performance of the automobile, and reduce the occurrence of accidents.

[0021] In the oil-resistant and hydrolysis-resistant electrical insulating composite material of the present invention, the film material and the paper material cooperate with each other, so that the composite material has good electrical insulation performance and a certain stiffness, which is convenient for inserting into the motor and avoiding creases that affect the application effect. At the same time, the paper material can make the composite material have good strain and strain resistance, so that the composite material can meet the appropriate bending requirements when used in the motor, and avoid the problem of easy breakage due to excessive brittleness of the film material during the application process. By adding polyphenylene sulfide staple fibers to the paper material, the oil and water resistance of the outer paper is improved, the protective performance of the outer paper is enhanced, and the oil and water resistance of the inner film is better improved. In addition, the paper material can protect the film material, avoiding the parts from scratching the film material that plays a leading insulating role during the insertion of the composite material into the motor, thereby causing problems with the insulation performance. The addition of suitable polyphenylene sulfide staple fibers to the paper material of the present invention can make the paper material have good oil resistance and hydrolysis resistance while protecting the appropriate strength performance, thereby improving the application effect and service life of the entire composite material.

[0022] In the preparation method of the present invention, S atoms are introduced into the main chain of the molecule, and the benzene ring and the S atoms are arranged alternately. The benzene ring improves the rigidity of the material, the sulfide improves the flexibility of the molecule, and the symmetrical structure of the molecule enhances the oil and water resistance of the material. On the one hand, the introduction of benzene sulfide improves the stiffness of the material, facilitates the slot in the production process, and improves production efficiency; on the other hand, the symmetrical molecular structure and the introduction of S atoms improve the oil and water resistance of the material, from the oil and water resistance of a single film material to the protection of the outer paper material, and through multiple protections, the oil and water resistance of the overall composite material is improved.

[0023] In the process of preparing the paper material of the present invention, an appropriate amount of polyphenylene sulfide staple fibers are added, and appropriate calendering process conditions are coordinated to prevent the paper material from having obvious fluffing and causing poor oil and water corrosion resistance, thereby making the strength performance more excellent and the paper material having better oil resistance and hydrolysis resistance. In addition, in the process of preparing the polyphenylene sulfide pellets of the present invention, the appropriate proportion of meta-dichlorobenzene and para-dichlorobenzene is matched, so that the strength performance of the film prepared by the polyphenylene sulfide pellets is more suitable, that is, it can avoid the problem of excessive rigidity causing crease breakage and thus affecting the breakdown voltage of the material, and it can also avoid the material being too soft and prone to creases, which affects the smooth slotting of the composite material in the motor and affects the production efficiency. Moreover, the flexibility and strength performance of the film are suitable, which can better broaden the material application scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a schematic diagram of the structure of the oil-resistant and hydrolysis-resistant electrical insulation composite material of the present invention; Figure 2 The photo comparison diagram of the composite material prepared in Example 1 before and after the oil resistance test; Figure 3 This is a comparison of the photos of the composite material prepared in Comparative Example 1 before and after the oil resistance test; Figure 4 It is a comparison diagram of the composite materials of Example 1 and Comparative Example 1 after 8 cycles of oil resistance test. DETAILED DESCRIPTION

[0025] The specific implementation of the present invention is described in detail below. The present invention can be implemented in many other ways than those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present invention, so the present invention is not limited by the specific embodiments disclosed.

[0026] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which the present invention belongs. The terms used are only for describing specific embodiments and are not intended to limit the present invention.

[0027] An oil-resistant and hydrolysis-resistant electrical insulation composite material, the composite material comprises a film material, paper materials adhered to both sides of the film material, and glue for bonding, the structure of the composite material is as follows Figure 1 As shown, the paper material is pasted on both sides of the membrane material through the adhesive layer. The membrane material is made of polyphenylene sulfide, and the pulp for preparing the paper material includes polyphenylene sulfide short fibers, meta-aramid short fibers and meta-aramid precipitation slurry.

[0028] In the embodiment of the present invention, the thickness of the film material is 45-55 μm, the thickness of the paper material is 45-55 μm, and the total thickness of the composite material is 190-230 μm. The thickness of each substrate and the total thickness of the composite material can be adjusted according to the usage scenario; in addition, two-layer, three-layer, five-layer or other multi-layer material composites can be performed according to the usage scenario, not limited to the three-layer structure described in the embodiment of the invention.

[0029] In an embodiment of the present invention, a method for preparing an oil-resistant and hydrolysis-resistant electrical insulating composite material is provided, and the preparation method includes the following steps S1-S8. However, it should be noted that the order of steps S1-S8 is not a limitation on the order of steps in the preparation method of the present application. For example, there is no strict requirement for the order of steps S1 and S2 below. The specific preparation method shall be subject to the scope of the claims (the same applies to other steps). Here, the entire preparation process is set to steps S1-S8 just for the sake of clarity.

[0030] A method for preparing an oil-resistant and hydrolysis-resistant electrical insulating composite material, the preparation method comprising: S1. Preparation of polyphenylene sulfide pellets; S2, preparation of polymerization solution; S3, preparation of membrane materials; S4, preparation of polyphenylene sulfide staple fibers; S5. Preparation of meta-aramid staple fibers; S6. Preparation of meta-aramid precipitation slurry; S7, preparation of paper; S8. Preparation of composite materials.

[0031] The specific process methods involved in the above steps S1-S8 are as follows: S1. The preparation process of polyphenylene sulfide pellets is as follows: Sodium sulfide is directly heated under vacuum to dehydrate, and then dichlorobenzene and anhydrous sodium sulfide are dissolved in a polar solvent under an inert gas atmosphere, and then a polymerization reaction is carried out under the action of an alkali metal salt to obtain a solid-liquid mixture, which is filtered, washed with water, and dried to obtain polyphenylene sulfide pellets.

[0032] The reaction principle of polyphenylene sulfide pellets is: .

[0033] The meaning of n in the above polymer structure is that the polymer structural unit is set repeatedly and no specific data needs to be set.

[0034] The reaction principle of the above polyphenylene sulfide pellets is specifically introduced as follows: a mixture of a certain proportion of m-dichlorobenzene and p-dichlorobenzene is reacted with sodium sulfide to form a polymer containing m-phenylene sulfide, p-phenylene sulfide, and fragments containing a mixture of m-phenylene and p-phenylene sulfide. The presence of m-phenylene sulfide fragments and poly-m-phenylene sulfide can improve the flexibility of the material after the polymer liquid is molded, and the presence of p-phenylene sulfide fragments and poly-p-phenylene sulfide can improve the rigidity of the material after molding.

[0035] In step S1, the dehydration conditions are: vacuum degree ≥ 0.096 MPa, heating at 85-90° C. for 0.8-1.2 h; heating at 115-118° C. for 0.4-0.6 h, and finally cooling the material to ≤ 40° C. under vacuum conditions to obtain dry anhydrous sodium sulfide.

[0036] In step S1, the inert gas is at least one of nitrogen and argon.

[0037] The polar solvent in step S1 is one or more of N-methylpyrrolidone (NMP), hexamethylphosphoric acid triamide (HMPA), N,N-dimethylacetamide, N-methylcaprolactam, and pyridine; preferably N-methylpyrrolidone (NMP).

[0038] In step S1, the molar ratio of anhydrous sodium sulfide to dichlorobenzene is 1:(0.95-0.98); the dichlorobenzene includes meta-dichlorobenzene and para-dichlorobenzene, and the molar ratio of meta-dichlorobenzene to para-dichlorobenzene is (3-4):1.

[0039] In step S1, the alkali metal salt includes one or more of sodium carbonate, potassium carbonate, sodium hydroxide, benzoate and phosphate, which serve as catalysts and auxiliary agents to accelerate the reaction.

[0040] In step S1, the polymerization reaction conditions are: reaction pressure 0-2 MPa, polymerization temperature 180-270° C., and reaction time 1-2 hours.

[0041] S2, the preparation process of the polymer solution is: Dissolve m-phenylenediamine in a polar solvent, add part of isophthaloyl chloride for prepolymerization, add neutralizer 1 to adjust the pH, and filter to obtain the prepolymer solution. Add the remaining isophthaloyl chloride in the raw material formula to the prepolymer solution for post-polymerization, and then add neutralizer 2 to adjust the pH to obtain the polymerization solution with a viscosity of 600-1500Po.

[0042] The polymerization reaction equation of the polymer solution is: .

[0043] The meaning of n in the above polymer structure is that the polymer structural unit is set repeatedly and no specific data needs to be set.

[0044] In step S2, the mass concentration of m-phenylenediamine in the polar solvent is 8%-14%.

[0045] In step S2, the molar ratio of m-phenylenediamine to isophthaloyl chloride is 1:(0.98-1.06).

[0046] In step S2, the polar solvent is one or more of N-methylpyrrolidone (NMP), hexamethylphosphoric acid triamide (HMPA), N,N-dimethylacetamide, N-methylcaprolactam, and pyridine, preferably N,N-dimethylacetamide.

[0047] In step S2, the prepolymerization reaction temperature is -5°C-5°C, the prepolymerization reaction time is 20-40min, the part of isophthaloyl chloride added during the prepolymerization is 80-95% of the total mass of isophthaloyl chloride in the formula, the neutralizer 1 is ammonia water, and the prepolymerization pH is adjusted to 6.7-7.2.

[0048] In step S2, the reaction temperature of the post-polymerization is 20°C-40°C, and the reaction time of the post-polymerization is 10-30min; the residual isophthaloyl chloride added during the post-polymerization is 5-20% of the total mass of the isophthaloyl chloride in the formula. The neutralizer 2 is any one or a combination of methylamine, dimethylamine, ethylamine, and diethylamine, and the pH of the post-polymerization is adjusted to 6.9-7.6.

[0049] S3. The preparation process of the membrane material is as follows: The polyphenylene sulfide pellets are dried under vacuum conditions, the dried polyphenylene sulfide pellets are melted at high temperature, extruded through a twin-screw extruder through a die to form a sheet, and then made into a film material through a bidirectional stretching and winding process.

[0050] In step S3, the drying vacuum degree is 0.01-0.02 MPa, the drying temperature is 110-140° C., and the drying time is 3-5 h.

[0051] In step S3, the melting temperature is 270-320°C, and the extrusion pressure is 3.0-9.0 MPa.

[0052] In step S3, the mold is a slit extrusion mold, the mold insulation time is 4-10 hours, and the mold temperature is 100-180°C.

[0053] In step S3, the stretching temperature is 130-270°C, the transverse stretching ratio is 1:(2-2.5), and the longitudinal stretching ratio is 1:(3-5).

[0054] S4. The preparation process of polyphenylene sulfide staple fiber is as follows: The polyphenylene sulfide pellets are dried under vacuum, and the dried polyphenylene sulfide pellets are melt-extruded into primary fibers through a twin-screw extruder at high temperature, and polyphenylene sulfide staple fibers are obtained through heat drawing, heat setting and slitting processes.

[0055] In step S4, the vacuum degree of drying is 0.01-0.02 MPa, the drying temperature is 110-140° C., and the drying time is 3-5 h.

[0056] In step S4, the high temperature melting temperature is 290-330°C, and the extrusion pressure is 1.0-6.0 MPa.

[0057] In step S4, the hot stretching temperature is 140-270°C, and the stretching ratio is 1:(4-7).

[0058] In step S4, the heat setting temperature is 250-320°C, and the drawing ratio is 1:(1-1.1).

[0059] S5. The preparation process of meta-aramid staple fiber is as follows: The polymerized liquid is filtered, coagulated, washed, dried, heat treated and cut to obtain the aramid staple fibers.

[0060] In step S5, the coagulation bath liquid is an aqueous solution of a polar solvent, and the mass concentration of the polar solvent in the coagulation bath liquid is in the range of 53%-63%, preferably 60%.

[0061] In step S5, the water washing is countercurrent washing.

[0062] In step S5, the drying temperature is 90-140°C.

[0063] In step S5, the heat treatment temperature is 280-330°C.

[0064] In step S5, the length of the aramid staple fibers is 9-20 mm.

[0065] S6. The preparation process of meta-aramid precipitation slurry is as follows: Water, glycerol and chloride salt are mixed to prepare a mixed solution, and then the mixed solution is mixed with a polymer solution in proportion to obtain a slurry. The slurry is subjected to high-speed shearing, cooling and molding, and multi-stage water washing to obtain the precipitation slurry.

[0066] In step S6, the mass ratio of water, glycerol and chloride salt is (30-50):(45-60):(5-10); the chloride salt is any one or a combination of calcium chloride, lithium chloride, sodium chloride, magnesium chloride and potassium chloride; In step S6, the mass ratio of the mixed liquid to the polymer liquid is (8-16):1.

[0067] In step S6, the high-speed shearing speed is 4000-7000 rpm / min, the temperature is 20-60° C., and the high-speed shearing time is 10-50 min.

[0068] In step S6, the cooling molding is performed in cold water at -10 to 5°C.

[0069] In step S6, the temperatures of the multi-stage water washing are: 10-20°C for the first stage water washing, 30-40°C for the second stage water washing, 50-60°C for the third stage water washing, 70-80°C for the fourth stage water washing, and 90-95°C for the fifth stage water washing, all of which are countercurrent water washing; In step S6, the average length of the meta-aramid fiber precipitation in the meta-aramid fiber precipitation slurry is 0.6-1.8 mm, and the specific surface area is 25-55 m 2 / g; the solid content of the meta-aramid fiber precipitation slurry is 4-7%.

[0070] S7. The preparation process of the paper material is as follows: First, the meta-aramid precipitated slurry is beaten and dispersed, and the polyphenylene sulfide staple fibers and the meta-aramid staple fibers are deflaked and dispersed to obtain deflaked mixed fibers. The precipitated slurry after beating and dispersion and the deflaked mixed fibers are then stirred and blended to obtain mixed pulp. The mixed pulp is then subjected to flow forming, pressing and drying, hot pressing, rewinding and slitting to obtain mixed paper materials.

[0071] In step S7, the mass ratio of the polyphenylene sulfide staple fibers, the meta-aramid staple fibers and the meta-aramid precipitation slurry is (3-4): (2-3): (3-5).

[0072] In step S7, the stirring speed of the stirring and blending is 2000-4000 rpm / min, and the stirring time is 15-25 min.

[0073] In step S7, the pressure of the pressing and drying is 1-3 MPa and the temperature is 130-170°C.

[0074] In step S7, the pressure of the hot pressing molding is 20-30 MPa and the temperature is 230-270°C.

[0075] S8. The preparation process of the composite material is as follows: After coating glue on both sides of the membrane material, drying is carried out in a drying oven, and the two sides are pressed with paper material to prepare a composite material, that is, an oil-resistant and hydrolysis-resistant composite material, which can be used after being left to mature.

[0076] In step S8, the glue is LA 2681 and LA 5094 mixed and used. The glue used in the embodiment of the present invention is LA 2681 and LA 5094 mixed in a weight ratio of 20: (1-1.5), but this is not a limitation of the technology of the present invention. As long as the paper material and the film material can be smoothly bonded, it belongs to the scope of the technical protection of the present invention.

[0077] In step S8, the coating amount is 5-50 g / m 2 .

[0078] In step S8, the drying oven temperature is 50-150°C.

[0079] In step S8, the pressing pressure is 0.3-0.6Mpa, and the pressing temperature is 35-70°C.

[0080] In step S8, the aging is carried out at a temperature of 25-90° C. for 2-6 days.

[0081] Example 1 A preparation method of an oil-resistant and hydrolysis-resistant electrical insulating composite material, the specific steps are as follows: S1. Preparation of polyphenylene sulfide pellets: Sodium sulfide is heated at a vacuum degree of 0.1 MPa and a temperature of 87°C for 1 hour, then the temperature is raised to 116°C and heated for 0.5 hour, and the material is cooled to 39°C to obtain dehydrated anhydrous sodium sulfide, and then the anhydrous sodium sulfide is dissolved in N-methylpyrrolidone under a nitrogen environment, and then 0.96 equivalents of dichlorobenzene (meta-dichlorobenzene and p-dichlorobenzene, the molar ratio is 3.5:1) are added, and the reaction is carried out under the action of potassium carbonate at a reaction pressure of 1 MPa and a polymerization temperature of 230°C for 1.5 hours to obtain a solid-liquid mixture, and finally the polyphenylene sulfide pellets are obtained after filtration, water washing and drying.

[0082] S2. Preparation of polymer solution: Dissolve m-phenylenediamine in N-methylpyrrolidone to prepare a solution with a mass concentration of 11%, add 90% equivalent of isophthaloyl chloride in total, stir at 0°C for 30 minutes to carry out prepolymerization reaction, add ammonia water to adjust the pH to 7.0, and obtain the prepolymer liquid after filtration, add the remaining 10% equivalent of isophthaloyl chloride to the prepolymer liquid, react at 30°C for 20 minutes, and then add diethylamine to adjust the pH to 7.1 to obtain a polymerization liquid with a viscosity of 900Po.

[0083] S3. Preparation of membrane materials: The polyphenylene sulfide pellets were dried at 125°C for 4 hours under a vacuum degree of 0.015 MPa, and then the dried polyphenylene sulfide pellets were melt-extruded through a twin-screw extruder at 295°C and a pressure of 6.0 MPa, and formed into sheets through a 140°C slit extrusion die, and then bidirectional stretching was completed at 200°C with a transverse stretching ratio of 1:2.3 and a longitudinal stretching ratio of 1:4, and finally rolled into a film material with a thickness of 45 μm.

[0084] S4. Preparation of polyphenylene sulfide staple fibers: Under a vacuum degree of 0.015 MPa, the polyphenylene sulfide pellets were dried at 125°C for 4 hours, and then the dried polyphenylene sulfide pellets were melt-extruded through a twin-screw extruder at 310°C under a pressure of 4.0 MPa to obtain primary fibers, which were then hot-stretched at 210°C with a stretch ratio of 1:6; then hot-stretched at 280°C with a stretch ratio of 1:1.05, and finally, 15 mm polyphenylene sulfide staple fibers were obtained through heat setting and slitting processes.

[0085] S5. Preparation of meta-aramid staple fibers: The polymer solution is filtered and then coagulated in a 58% N-methylpyrrolidone aqueous solution (coagulation bath) through a spinneret to form primary fibers. After countercurrent water washing, the fibers are dried on a drying roller at 110°C. The dried fibers are heat treated in a channel at 305°C and finally cut into 14mm meta-aramid staple fibers.

[0086] S6. Preparation of meta-aramid precipitation slurry: Water, glycerol and chloride salt are mixed in a mass ratio of 40:53:7 to prepare a mixed solution, and then the mixed solution is mixed with a polymer solution in a weight ratio of 12:1 to obtain a slurry, the slurry is subjected to high-speed shearing at a speed of 6000 rpm / min for 30 minutes at a temperature of 40°C, and then cooled and formed in cold water at -1°C, and then subjected to multi-stage countercurrent washing, with the first stage at 15°C, the second stage at 35°C, the third stage at 55°C, the fourth stage at 75°C, and the fifth stage at 91°C, to obtain a meta-aramid precipitation slurry, wherein the average length of the meta-aramid precipitation fibers in the meta-aramid precipitation slurry is 1.2 mm, and the specific surface area is 32 m 2 / g.

[0087] S7. Preparation of paper: First, the meta-aramid precipitated slurry is beaten and dispersed, and the polyphenylene sulfide staple fiber and the meta-aramid staple fiber are deflaked and dispersed to obtain deflaked mixed fibers. The mass ratio of polyphenylene sulfide staple fiber, meta-aramid staple fiber and meta-aramid precipitated slurry is 3.5:2.5:4. Then, the precipitated slurry and the deflaked mixed fibers after beating and dispersion are stirred at a speed of 3000 rpm / min for 20 minutes to obtain mixed pulp. Then, the mixed pulp is formed by flow conveying, and then pressed and dried under a pressure of 2MPa and a temperature of 150°C. Then, it is hot-pressed at a pressure of 22MPa and a temperature of 250°C. Finally, the mixed paper material is obtained after rewinding and slitting.

[0088] S8. Preparation of composite materials: Coat both sides of the membrane with 35g / m 2 After gluing, it is dried in a drying oven at 90°C, and the two sides are pressed with paper at a pressure of 0.5MPa and 45°C to prepare a composite material, that is, an oil-resistant and hydrolysis-resistant composite material, which can be used after being placed in an environment of 70°C for 3 days to complete the aging. The thickness of the composite material is 210μm.

[0089] Example 2 A preparation method of an oil-resistant and hydrolysis-resistant electrical insulating composite material, the specific steps are as follows: S1. Preparation of polyphenylene sulfide pellets: Sodium sulfide is heated at a vacuum degree of 0.1 MPa and a temperature of 90°C for 0.8 h, then the temperature is raised to 118°C and heated for 0.4 h, and the material is cooled to 39°C to obtain dehydrated anhydrous sodium sulfide, and then the anhydrous sodium sulfide is dissolved in N-methylpyrrolidone under a nitrogen environment, and then 0.95 equivalents of dichlorobenzene (meta-dichlorobenzene and p-dichlorobenzene, the molar ratio is 3:1) are added, and the reaction is carried out under a reaction pressure of 2 MPa and a polymerization temperature of 180°C under the action of sodium carbonate for 2 hours to obtain a solid-liquid mixture, and finally the polyphenylene sulfide pellets are obtained after filtration, water washing and drying.

[0090] S2. Preparation of polymer solution: Dissolve m-phenylenediamine in N,N-dimethylacetamide to prepare a solution with a mass concentration of 14%, add 80% equivalent of isophthaloyl chloride, stir for 30 minutes at -5°C for prepolymerization, add ammonia water to adjust the pH to 7.0, filter to obtain the prepolymer solution, add the remaining 20% ​​equivalent of isophthaloyl chloride to the prepolymer solution, react at 40°C for 10 minutes, add diethylamine to adjust the pH to 7.2, and obtain a polymerization solution with a viscosity of 1050Po.

[0091] S3. Preparation of membrane materials: The polyphenylene sulfide pellets were dried at 110°C for 5 hours under a vacuum degree of 0.02 MPa, and then the dried polyphenylene sulfide pellets were melt-extruded through a twin-screw extruder at 320°C and 3.0 MPa, and formed into sheets through a 180°C slit extrusion die, and then bidirectionally stretched at 270°C with a transverse stretching ratio of 1:2.5 and a longitudinal stretching ratio of 1:5, and finally rolled into a film material having a thickness of 50 μm.

[0092] S4. Preparation of polyphenylene sulfide staple fibers: Under a vacuum degree of 0.02MPa, the polyphenylene sulfide pellets are dried at 110°C for 5h, and then the dried polyphenylene sulfide pellets are melt-extruded through a twin-screw extruder at 290°C under a pressure of 1.0MPa to obtain primary fibers, which are then hot-stretched at 140°C with a stretch ratio of 1:4; then hot-stretched at 250°C with a stretch ratio of 1:1, and finally 9mm polyphenylene sulfide staple fibers are obtained through heat setting and slitting processes.

[0093] S5. Preparation of meta-aramid staple fibers: The polymer solution is filtered and then coagulated in a 60% N,N-dimethylacetamide aqueous solution (coagulation bath) through a spinneret to form primary fibers. After countercurrent water washing, the fibers are dried on a drying roller at 90°C. The dried fibers are heat treated in a channel at 280°C and finally cut into 20mm meta-aramid staple fibers.

[0094] S6. Preparation of meta-aramid precipitation slurry: Water, glycerol and chloride salt are mixed in a mass ratio of 30:60:10 to prepare a mixed solution, and then the mixed solution is mixed with a polymer solution in a weight ratio of 8:1 to obtain a slurry, the slurry is subjected to high-speed shearing at a speed of 7000 rpm / min for 50 minutes at a temperature of 20°C, and then cooled and formed in cold water at -10°C, and then multi-stage countercurrent washing is performed, with the first stage at 10°C, the second stage at 30°C, the third stage at 50°C, the fourth stage at 70°C, and the fifth stage at 90°C to obtain a meta-aramid precipitation slurry, wherein the average length of the meta-aramid precipitation fibers in the meta-aramid precipitation slurry is 1.8 mm, and the specific surface area is 25 m 2 / g.

[0095] S7. Preparation of paper: First, the meta-aramid precipitated slurry is beaten and dispersed, and the polyphenylene sulfide staple fiber and the meta-aramid staple fiber are deflaked and dispersed to obtain deflaked mixed fibers. The mass ratio of polyphenylene sulfide staple fiber, meta-aramid staple fiber and meta-aramid precipitated slurry is 3:2:5. Then, the precipitated slurry and the deflaked mixed fibers after beating and dispersion are stirred at a speed of 2000rpm / min for 25min to obtain mixed pulp. Then, the mixed pulp is formed by flow conveying, and then pressed and dried under the conditions of pressure 1MPa and temperature 170℃, and then hot-pressed under the conditions of pressure 20MPa and temperature 230℃, and finally, the mixed paper material is obtained after rewinding and slitting.

[0096] S8. Preparation of composite materials: Coat both sides of the membrane with 5g / m 2 After gluing, it is dried in a drying oven at 50°C, and the two sides are pressed with paper at a pressure of 0.3MPa and 35°C to prepare a composite material, that is, an oil-resistant and hydrolysis-resistant composite material. It can be used after being placed in an environment of 25°C for 6 days to complete maturation. The thickness of the composite material is 190μm.

[0097] Example 3 A preparation method of an oil-resistant and hydrolysis-resistant electrical insulation composite material, the specific steps are as follows: S1. Preparation of polyphenylene sulfide pellets: Sodium sulfide is heated at a vacuum degree of 0.1 MPa and a temperature of 85°C for 1.2 h, then the temperature is raised to 115°C and heated for 0.6 h, and the material is cooled to 39°C to obtain dehydrated anhydrous sodium sulfide, and then the anhydrous sodium sulfide is dissolved in N-methylpyrrolidone under a nitrogen environment, and then 0.98 equivalents of dichlorobenzene (meta-dichlorobenzene and para-dichlorobenzene, the molar ratio is 4:1) are added, and the reaction is carried out under the action of potassium carbonate at a reaction pressure of 0 MPa and a polymerization temperature of 270°C for 1 hour to obtain a solid-liquid mixture, and finally the polyphenylene sulfide pellets are obtained after filtration, water washing and drying.

[0098] S2. Preparation of polymer solution: Dissolve m-phenylenediamine in N,N-dimethylacetamide to prepare a solution with a mass concentration of 8%, add 90% equivalent of isophthaloyl chloride in total, stir for 20 minutes at 5°C for prepolymerization, add ammonia water to adjust the pH to 6.9, filter to obtain the prepolymer solution, add the remaining 5% equivalent of isophthaloyl chloride to the prepolymer solution, react at 20°C for 30 minutes, add diethylamine to adjust the pH to 7.5, and obtain a polymerization solution with a viscosity of 850Po.

[0099] S3. Preparation of membrane materials: The polyphenylene sulfide pellets were dried at 140°C for 3 hours under a vacuum degree of 0.01 MPa, and then the dried polyphenylene sulfide pellets were melt-extruded through a twin-screw extruder at 270°C and a pressure of 9.0 MPa, and formed into sheets through a 100°C slit extrusion die, and then bidirectional stretching was completed at 130°C with a transverse stretching ratio of 1:2 and a longitudinal stretching ratio of 1:3, and finally rolled into a film material with a thickness of 55 μm.

[0100] S4. Preparation of polyphenylene sulfide staple fibers: Under a vacuum degree of 0.01 MPa, the polyphenylene sulfide pellets are dried at 140°C for 3 hours, and then the dried polyphenylene sulfide pellets are melt-extruded through a twin-screw extruder at 330°C under a pressure of 6.0 MPa to obtain primary fibers, which are then hot-stretched at 270°C with a stretch ratio of 1:7; then hot-stretched at 320°C with a stretch ratio of 1:1.1, and finally 20 mm polyphenylene sulfide staple fibers are obtained through heat setting and slitting processes.

[0101] S5. Preparation of meta-aramid staple fibers: The polymer solution is filtered and then coagulated in a 63% N-methylpyrrolidone aqueous solution (coagulation bath) through a spinneret to form primary fibers. After countercurrent water washing, the fibers are dried on a drying roller at 140°C. The dried fibers are heat treated in a channel at 330°C and finally cut into 10 mm meta-aramid staple fibers.

[0102] S6. Preparation of meta-aramid precipitation slurry: Water, glycerol and chloride salt are mixed in a mass ratio of 50:45:5 to prepare a mixed solution, and then the mixed solution is mixed with a polymer solution in a weight ratio of 16:1 to obtain a slurry, the slurry is subjected to high-speed shearing at a speed of 4000 rpm / min for 10 minutes at a temperature of 60°C, and then cooled and formed in cold water at 5°C, and then multi-stage countercurrent washing is performed, with the first stage at 20°C, the second stage at 40°C, the third stage at 60°C, the fourth stage at 80°C, and the fifth stage at 95°C to obtain a meta-aramid precipitation slurry, wherein the average length of the meta-aramid precipitation fibers in the meta-aramid precipitation slurry is 0.6 mm, and the specific surface area is 55m 2 / g.

[0103] S7. Preparation of paper: First, the meta-aramid precipitated slurry is beaten and dispersed, and the polyphenylene sulfide staple fiber and the meta-aramid staple fiber are deflaked and dispersed to obtain deflaked mixed fibers. The mass ratio of polyphenylene sulfide staple fiber, meta-aramid staple fiber and meta-aramid precipitated slurry is 4:3:3. Then, the precipitated slurry and the deflaked mixed fibers after beating and dispersion are stirred at a speed of 4000rpm / min for 15min to obtain mixed pulp. Then, the mixed pulp is formed by flow conveying, and then pressed and dried under the conditions of pressure 3MPa and temperature 130℃, and then hot-pressed under the conditions of pressure 30MPa and temperature 270℃, and finally, the mixed paper material is obtained after rewinding and slitting.

[0104] S8. Preparation of composite materials: Coat both sides of the membrane with 50g / m 2 After gluing, it is dried in a drying oven at 150°C, and the two sides are pressed with paper at a pressure of 0.6MPa and 70°C to prepare a composite material, that is, an oil-resistant and hydrolysis-resistant composite material. It can be used after being placed in an environment of 90°C for 2 days to complete maturation. The thickness of the composite material is 238μm.

[0105] Comparative Example 1 Preparation of an electrical insulating composite material: The composite material was prepared by the same method as in Example 1, except that polyphenylene sulfide staple fibers were not added during the preparation of the paper material in this comparative example 1. The specific steps are as follows: S1. Preparation of polyphenylene sulfide pellets: The preparation method is the same as Example 1.

[0106] S2. Preparation of polymer solution: The preparation method is the same as Example 1.

[0107] S3. Preparation of membrane materials: The preparation method is the same as Example 1.

[0108] S4. Preparation of polyphenylene sulfide staple fibers: In this comparative example 1, there is no need to prepare polyphenylene sulfide staple fibers.

[0109] S5. Preparation of meta-aramid staple fibers: The preparation method is the same as Example 1.

[0110] S6. Preparation of meta-aramid precipitation slurry: The preparation method is the same as Example 1.

[0111] S7. Preparation of paper: First, the meta-aramid precipitated slurry is beaten and dispersed, and the meta-aramid staple fibers are deflaked and dispersed to obtain deflaked staple fibers. The mass ratio of meta-aramid staple fibers and meta-aramid precipitated slurry is 7:3. Then, the precipitated slurry and deflaked staple fibers after beating and dispersion are stirred at a speed of 4000rpm / min for 15min to obtain pulp. After the pulp is formed by flow conveying, it is pressed and dried under a pressure of 3MPa and a temperature of 130°C, and then hot-pressed under a pressure of 30MPa and a temperature of 270°C. Finally, the paper material is obtained after rewinding and slitting.

[0112] S8. Preparation of composite materials: The preparation method is the same as Example 1.

[0113] Comparative Example 2 Preparation of an electrical insulating composite material: The composite material was prepared by the same method as in Example 1, except that when preparing polyphenylene sulfide pellets in Comparative Example 2, only m-dichlorobenzene was used as dichlorobenzene, and p-dichlorobenzene was not added. The other preparation methods were the same as in Example 1.

[0114] Comparative Example 3 Preparation of an electrical insulating composite material: The composite material was prepared by the same method as in Example 1, except that: when preparing polyphenylene sulfide pellets in this comparative example 3, the dosage ratio of p-dichlorobenzene was increased, and the molar ratio of intermediate dichlorobenzene to ground dichlorobenzene in this comparative example 3 was 1:1. The other preparation methods were the same as in Example 1.

[0115] Comparative Example 4 Preparation of an electrical insulating composite material: The composite material was prepared by the same method as in Example 1, except that: in the paper preparation process in step S7 of this comparative example 4, the dosage ratio of polyphenylene sulfide staple fibers was increased, and the mass ratio of polyphenylene sulfide staple fibers, meta-aramid staple fibers, and meta-aramid precipitation slurry in this comparative example 4 was 5:2:3, and the other preparation methods were the same as in Example 1.

[0116] Comparative Example 5 Preparation of an electrical insulating composite material: The composite material was prepared by the same method as in Example 1, except that: in step S7 of this comparative example 5, the pressure of hot pressing molding was reduced, and the pressure of hot pressing molding in this comparative example 5 was 12 MPa.

[0117] Comparative Example 6 Preparation of an electrical insulating composite material: The composite material was prepared by the same method as in Example 1, except that in step S8 of this comparative example 6, the pressing temperature was lowered, and the pressing temperature in this comparative example 6 was 15°C.

[0118] The composite materials prepared in the above examples and comparative examples were subjected to performance tests, wherein the test methods involved are as follows.

[0119] Oil and hydrolysis resistance test method: The ATF oil used is Castrol BOT383, 0.2%~0.5% volume of deionized water is added, and then shear stirring is carried out at a speed of 8000r / min for 5 minutes to fully mix the oil and water; test temperature: 25℃→(155℃ / 40h~-45℃ / 8h)×8 cycles→25℃, heated from 25℃ to 155℃, the heating rate is about 3℃ / min, during the test, 155℃ and -45℃ are directly switched by temperature impulse, and the switching time is less than 30s (two-box method, sample conversion outside the box).

[0120] The testing standards involved are: GB / T 5591.2-2017 Flexible composite materials for electrical insulation Part 2: Test methods; GB / T 20629.2-2013 "Non-cellulose paper for electrical use Part 2: Test methods"; GB / T 7354-2018 "High voltage test technology - Partial discharge measurement".

[0121] The changes in material performance indicators of the composite materials before and after 8 cycles of oil resistance and hydrolysis resistance testing are shown in Tables 1 to 3 below.

[0122] Table 1 Data on the retention rate of performance indicators of the composite materials of Examples 1-3 and Comparative Examples 1-2 after oil resistance and hydrolysis resistance

[0123] Note: The "conventional oil-resistant and water-resistant products" in Table 1 above refer to: 50μm pure aramid paper is compounded with PI film, and LA2681 and LA5094 are used as compound glue to prepare a composite material product with a thickness of 210μm. Pure aramid paper refers to Minshida YT564-0.05, without any other fibers.

[0124] In addition, during the oil and hydrolysis resistance test, the composite materials of Comparative Examples 3, 4, 5 and 6 all failed the oil and hydrolysis resistance test and showed delamination and blistering.

[0125] Table 2 Performance index data of composite materials of Examples 1-3 and Comparative Examples 1-2

[0126] Table 3 Performance index data of composite materials of comparative examples 3-6

[0127] It can be seen from the retention rate of performance indicators before and after the oil resistance and hydrolysis resistance test that the composite materials prepared by the preparation method of the present invention in Examples 1 to 3 have good oil resistance and hydrolysis resistance. Compared with conventional oil resistance and hydrolysis resistance products, the composite materials prepared by the present invention have a higher retention rate. This shows that after 8 cycles of oil resistance and hydrolysis resistance tests, the composite material can still maintain good mechanical properties and electrical insulation properties, which can effectively improve the service life of the composite material in the motor. Moreover, the composite material has suitable strength properties, which is more conducive to installation operations in the motor.

[0128] From the comparison of the experimental results of Comparative Example 1 and Example 1, it can be seen that if polyphenylene sulfide staple fibers are not added when making paper, the mechanical properties of the prepared composite material, such as stiffness, are significantly lower than those of the composite material prepared by the scheme of the present invention. After the oil and hydrolysis resistance test, its performance retention rate also decreases significantly. This shows that the addition of polyphenylene sulfide fibers to paper can effectively improve the protectiveness of the outer paper to the inner film material and improve the oil and water resistance of the overall material. At the same time, the addition of polyphenylene sulfide fibers can also effectively improve the performance indicators of paper, further illustrating that the paper and film materials in the preparation method of the present invention cooperate with each other, which is more conducive to obtaining a composite material with excellent performance and durability.

[0129] From the comparison of the experimental results of Comparative Example 2 and Example 1, it can be seen that if only m-dichlorobenzene is used as dichlorobenzene and p-dichlorobenzene is not added when preparing polyphenylene sulfide pellets, the stiffness of the prepared composite material is significantly reduced, which is easy to cause paper plugging in the slot during the actual production process, affecting production efficiency. In addition, during the oil resistance and hydrolysis resistance test, the retention rate of the sample prepared in Comparative Example 2 is significantly lower than that of Example 1, but it is significantly higher than the indicators of Comparative Example 1 and conventional oil-resistant water products, which shows that the introduction of sulfide functional groups has a certain oil resistance and hydrolysis resistance effect.

[0130] From the comparison of the experimental results of Comparative Example 3 and Example 1, it can be seen that if the proportion of p-dichlorobenzene is increased when preparing polyphenylene sulfide pellets, the strength of the prepared fiber is relatively large, and in the subsequent process of preparing paper, it is easy to cause fluff on the surface of the paper, which weakens the protective effect of the outer paper on the inner insulating film material. In addition, the increase in the use of p-dichlorobenzene causes the rigidity of the overall material to be relatively strong, and it is easy to crack during the bending process of the slot, thereby increasing the defective rate of the motor product. Therefore, the polyphenylene sulfide pellets are prepared using the proportion of m-dichlorobenzene and p-dichlorobenzene defined in the present invention, and the resulting composite material has more suitable strength performance and is more conducive to application in motors.

[0131] From the comparison of the experimental results of Comparative Example 4 and Example 1, it can be seen that if the proportion of polyphenylene sulfide staple fibers is increased during the paper preparation process, it is easy to cause difficulties in hot pressing of the paper, the paper surface becomes fuzzy, the bonding is not strong, and the product is prone to stratification, which also weakens the protective effect of the outer paper on the inner insulating film material.

[0132] From the comparison of the experimental results of Comparative Example 5 and Example 1, it can be seen that if the pressure of hot pressing molding is reduced during paper material preparation, the paper material is prone to fuzzing, resulting in loose glue bonding and delamination, which ultimately leads to a decrease in the strength performance of the composite material and weakens the protective effect of the outer paper on the inner insulating film material. In the preparation method of the present invention, polyphenylene sulfide staple fibers are added during paper material preparation, and a higher hot pressing pressure is used, which is more conducive to obtaining a composite material with excellent performance.

[0133] From the comparison of the experimental results of Comparative Example 6 and Example 1, it can be seen that if the pressing temperature is lowered during the preparation of the composite material, the film material and the paper material will not be sufficiently bonded, resulting in delamination of the composite material. In the preparation method of the present invention, appropriate heating during the pressing process is beneficial to fully bond the film material and the paper material, and enhance the protective effect of the paper material and the glue on the film material, thereby obtaining a composite material with excellent comprehensive performance.

[0134] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are exhaustively listed. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0135] For those skilled in the art, several modifications and improvements may be made without departing from the concept of the present invention, all of which belong to the protection scope of the present invention. The protection scope of the present invention shall be based on the attached claims.

Claims

1. An oil-resistant and hydrolysis-resistant electrical insulating composite material, the composite material comprising a film material, paper materials adhered to both sides of the film material, and glue for bonding, characterized in that: The membrane material is made of polyphenylene sulfide, and the pulp used to prepare the paper material includes polyphenylene sulfide staple fibers, meta-aramid staple fibers and meta-aramid precipitation slurry.

2. The oil-resistant and hydrolysis-resistant electrical insulating composite material according to claim 1, characterized in that: The polyphenylene sulfide is prepared by polymerization reaction of anhydrous sodium sulfide and dichlorobenzene, wherein the molar ratio of the anhydrous sodium sulfide to the dichlorobenzene is 1:(0.95-0.98), the dichlorobenzene includes meta-dichlorobenzene and para-dichlorobenzene, and the molar ratio of meta-dichlorobenzene to para-dichlorobenzene is (3-4):

1.

3. The oil-resistant and hydrolysis-resistant electrical insulating composite material according to claim 1, characterized in that: In the pulp, the mass ratio of the polyphenylene sulfide staple fibers, the meta-aramid staple fibers and the meta-aramid precipitation slurry is (3-4): (2-3): (3-5).

4. The oil-resistant and hydrolysis-resistant electrical insulating composite material according to claim 1, characterized in that: The length of the polyphenylene sulfide staple fiber is 9-20 mm; the length of the meta-aramid staple fiber is 9-20 mm; the solid content of the meta-aramid fiber in the meta-aramid precipitation slurry is 4-7%, the average length of the meta-aramid fiber is 0.6-1.8 mm, and the specific surface area of ​​the meta-aramid fiber is 25-55 m 2 / g.

5. A method for preparing an oil-resistant and hydrolysis-resistant electrical insulating composite material according to any one of claims 1 to 4, characterized in that: The preparation method is: S1. Preparation of polyphenylene sulfide pellets: Under inert gas conditions, dichlorobenzene and anhydrous sodium sulfide are dissolved in a polar solvent, and a polymerization reaction is carried out under the action of an alkali metal salt, and after the reaction is completed, polyphenylene sulfide pellets are obtained through post-treatment; S2. Preparation of membrane and paper materials: Film preparation: After the polyphenylene sulfide pellets are melt-extruded into sheets, they are bidirectionally drawn and rolled to obtain film materials; Paper material preparation: polyphenylene sulfide pellets are melted into filaments to obtain polyphenylene sulfide staple fibers, and polyphenylene sulfide staple fibers, meta-aramid staple fibers and meta-aramid precipitated slurry are mixed and then papered to obtain paper material; S3. Preparation of composite materials: Glue is applied on both sides of the membrane material, and after drying, it is pressed with paper material and cured to obtain a composite material.

6. The method for preparing an oil-resistant and hydrolysis-resistant electrical insulating composite material according to claim 5, characterized in that: In step S1, the polymerization reaction temperature is 180-270° C., the reaction pressure is 0-2 MPa, and the reaction time is 1-2 h.

7. The method for preparing an oil-resistant and hydrolysis-resistant electrical insulating composite material according to claim 5, characterized in that: The process of preparing the membrane material in step S2 is as follows: The dried polyphenylene sulfide pellets are melted at high temperature and then extruded through a twin-screw extruder through a die to form a sheet, which is then bidirectionally drawn and rolled to obtain a film material; The high temperature melting temperature is 270-320°C, and the extrusion pressure is 3.0-9.0MPa; The die is a slit extrusion die, the die insulation time is 4-10h, and the die temperature is 100-180°C; The drawing temperature is 130-270°C, the transverse drawing ratio is 1:(2-2.5), and the longitudinal drawing ratio is 1:(3-5).

8. The method for preparing an oil-resistant and hydrolysis-resistant electrical insulating composite material according to claim 5, characterized in that: The process of preparing paper material in step S2 is as follows: First, the meta-aramid precipitated slurry is beaten and dispersed, and the polyphenylene sulfide staple fiber and the meta-aramid staple fiber are debonded and dispersed to obtain debonded mixed fibers, and then the precipitated slurry after beating and dispersion and the debonded mixed fibers are stirred and blended uniformly to obtain mixed pulp, and the mixed pulp is subjected to flow forming, pressing and drying, hot pressing forming, and rewinding and slitting to obtain paper material; The pressure of the pressing and drying is 1-3 MPa, and the temperature of the pressing and drying is 130-170°C; The pressure of the hot pressing molding is 20-30 MPa, and the temperature of the hot pressing molding is 230-270°C.

9. The method for preparing an oil-resistant and hydrolysis-resistant electrical insulating composite material according to claim 5, characterized in that: In step S3, the amount of glue applied on one side of the film is 5-50 g / m 2 The drying temperature is 50-150℃, the pressure during pressing is 0.3-0.6Mpa, and the pressing temperature is 35-70℃.

10. An application of the oil-resistant and hydrolysis-resistant electrical insulation composite material according to any one of claims 1 to 4, characterized in that: The composite material is applied in a motor.

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