Salt-spray-resistant insulating material, preparation method and application

Abstract

The invention relates to a salt-spray-resistant insulating material, a preparation method and application, a reinforcing material is impregnated with a benzoxazine resin composition, the impregnated reinforcing material is dried to obtain a prepreg, and then the prepreg is fed into a vacuum hot press for hot press molding; during hot press molding, megasonic vibration is applied to the prepreg by a megasonic vibration plate arranged in the vacuum hot press; and after the hot press molding is finished, cooling to room temperature to obtain the salt-spray-resistant insulating material. According to the invention, the reinforcing material is impregnated with the benzoxazine resin composition, and no small molecules are released in the benzoxazine resin curing process; the megasonic vibration plate composed of the three megasonic emission rods with different megasonic frequencies is adopted, the superimposed megasonic waves can effectively promote the phenol type benzoxazine resin to be compounded with the reinforcing material in the hot press molding process, so that holes in the insulating material are further reduced, the compactness of the insulating material is higher, the insulating material can resist common salt mist, and the service life of the insulating material is prolonged. And the salt fog resistance to acid salt fog is also excellent.

Description

Technical Field

[0001] The invention relates to a salt-fog resistant insulating material, a preparation method and application thereof, and belongs to the technical field of insulating materials. Background Art

[0002] In the field of insulating materials, resin-based composite materials have the advantages of light weight, high strength, and good insulation, and are widely used. Take epoxy resin as an example. As a matrix material, it has the advantages of excellent corrosion resistance and good chemical compatibility with reinforcing fibers, and is suitable for the oil industry. Glass fiber has good heat resistance, chemical stability, and excellent tensile strength. It is used as a reinforcing material. The insulating materials prepared by hot pressing are widely used.

[0003] However, whether it is epoxy resin, phenolic resin, etc., small molecules will be released during the curing process. In addition, the compounding between them and the reinforcing materials will cause some micropores or nanopores to exist in the cured insulating material. This can be proved by the fact that epoxy resin composite materials generally have a certain water absorption. Due to the presence of micropores or nanopores, the salt spray resistance of epoxy resin composite materials is limited, especially the salt spray resistance to acidic salt spray is worse. This limits the application of electrical insulation materials in some special fields, such as the petroleum field and the marine field.

[0004] Based on this, the present invention is proposed. Summary of the invention

[0005] In view of the deficiencies in the prior art, the present invention provides a salt spray resistant insulating material, a preparation method and an application thereof. The specific technical scheme is as follows:

[0006] In a first aspect, a salt spray resistant insulating material is provided, wherein a reinforcing material is impregnated with a benzoxazine resin composition, the impregnated reinforcing material is dried to obtain a prepreg, and then the prepreg is sent to a vacuum hot press for hot pressing; during hot pressing, a megasonic vibration plate provided in the vacuum hot press applies megasonic vibration to the prepreg; after the hot pressing is completed, the prepreg is cooled to room temperature to obtain the salt spray resistant insulating material.

[0007] A further improvement is that the megasonic vibration plate is embedded in a pressing plate in a vacuum hot press, and a plurality of megasonic vibration plates are provided; the megasonic vibration plate comprises a metal plate body, in which a first megasonic emission rod, a second megasonic emission rod and a third megasonic emission rod are embedded, the second megasonic emission rod is located between the first megasonic emission rod and the third megasonic emission rod, and portions of the first megasonic emission rod, the second megasonic emission rod and the third megasonic emission rod located outside the megasonic vibration plate are cooled by cooling water.

[0008] As a further improvement, the megasonic frequency of the first megasonic emission rod is 1.13 MHz, the megasonic frequency of the third megasonic emission rod is 1.27 MHz, and the megasonic frequency of the second megasonic emission rod is 0.69 MHz; the power of the first megasonic emission rod, the second megasonic emission rod and the third megasonic emission rod are all 2100 W.

[0009] As a further improvement, the benzoxazine resin composition is composed of 90 to 100 parts by mass of phenolic benzoxazine resin, 0.5 to 0.6 parts by mass of 2-methylimidazole and 8 to 10 parts by mass of butanone.

[0010] A further improvement is that during hot pressing, vacuum is first drawn to a degree of vacuum of -60 mmHg, the temperature of the pressing plate is raised to 170-175°C, and after the pressure of the pressing plate on the prepreg is increased to 2.1-2.2 MPa, heat preservation and pressure maintenance are started and the megasonic vibration plate is started to apply megasonic vibration to the prepreg. After 25 minutes of megasonic vibration, the megasonic vibration is stopped for 35 minutes, and then the megasonic vibration is continued for 60 minutes; thereafter, the megasonic vibration is stopped, the temperature is lowered to room temperature, and the vacuum is broken to obtain the salt spray resistant insulating material.

[0011] As a further improvement, the temperature for drying the impregnated reinforcement material is 155-165°C.

[0012] As a further improvement, the reinforcing material may be glass fiber, glass fiber cloth, glass felt, ceramic fiber, graphite fiber, carbon fiber, etc.

[0013] In a second aspect, a method for preparing a salt spray resistant insulating material comprises the following steps:

[0014] Step 1, preparing a benzoxazine resin composition in a stirred tank;

[0015] Step 2, the benzoxazine resin composition is impregnated into the reinforcing material through a glue coating machine;

[0016] Step 3, sending the impregnated reinforcement material into an oven for drying to obtain a prepreg;

[0017] Step 4: After the prepreg is cut and stacked, it is placed in a mold and then sent to a vacuum hot press for hot pressing. During hot pressing, the megasonic vibration plate applies megasonic vibration to the prepreg.

[0018] Step 5: After the hot pressing is completed, the mixture is cooled to room temperature to obtain the salt spray resistant insulating material.

[0019] A third aspect provides an application of a salt spray resistant insulating material, wherein the salt spray resistant insulating material is applied to electrical insulating materials resistant to acid salt spray.

[0020] Beneficial effects of the present invention:

[0021] The present invention adopts a benzoxazine resin composition to impregnate a reinforcing material. During the curing process of the benzoxazine resin, no small molecules are released, and the benzoxazine resin has the characteristics of high modulus, high strength, good heat resistance, low water absorption, etc. In addition, a megasonic vibration plate composed of three megasonic emission rods with different megasonic frequencies is adopted, and the superimposed megasonic waves can effectively promote the phenol-type benzoxazine resin to be compounded with the reinforcing material during the hot pressing process, thereby further reducing the holes in the insulating material, and the insulating material has higher density, and is not only resistant to ordinary salt spray, but also has excellent salt spray resistance to acidic salt spray. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of the structure of the megasonic vibration plate of the present invention. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0024] In the description of the present invention, it should be noted that, unless otherwise specified, "multiple" means two or more than two; the directions or positional relationships indicated by the terms "upper", "lower", "left", "right", "inner", "outer", "front end", "rear end", "head", "tail", etc. are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", "third", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0025] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0026] Example 1

[0027] A salt spray resistant insulating material is provided. A reinforcing material is impregnated with a benzoxazine resin composition, the impregnated reinforcing material is dried to obtain a prepreg, and then the prepreg is sent to a vacuum hot press for hot pressing. During the hot pressing, a megasonic vibration plate arranged in the vacuum hot press applies megasonic vibration to the prepreg. After the hot pressing is completed, the prepreg is cooled to room temperature to obtain the salt spray resistant insulating material.

[0028] Example 2

[0029] A method for preparing a salt spray resistant insulating material comprises the following steps:

[0030] Step 1, preparing a benzoxazine resin composition in a stirred tank;

[0031] The benzoxazine resin composition is composed of 10 kg of phenolic benzoxazine resin, 0.05 kg of 2-methylimidazole and 1 kg of butanone.

[0032] Step 2: The benzoxazine resin composition is impregnated into the reinforcing material through a glue coating machine.

[0033] Step 3: Place the impregnated reinforcement material into an oven for drying at a temperature of 155-165° C. to obtain a prepreg.

[0034] Step 4: After the prepreg is cut and stacked, it is placed in a mold and then sent to a vacuum hot press for hot pressing. During hot pressing, the megasonic vibration plate applies megasonic vibration to the prepreg.

[0035] In Example 1, Figure 1 As shown, the megasonic vibration plate 10 is embedded in a pressing plate in a vacuum hot press, and a plurality of megasonic vibration plates 10 are provided; the megasonic vibration plate 10 comprises a metal plate body 10, in which a first megasonic emission rod 21, a second megasonic emission rod 22 and a third megasonic emission rod 23 are embedded, the second megasonic emission rod 22 is located between the first megasonic emission rod 21 and the third megasonic emission rod 23, and portions of the first megasonic emission rod 21, the second megasonic emission rod 22 and the third megasonic emission rod 23 located outside the megasonic vibration plate 10 are cooled by cooling water.

[0036] The megasonic frequency of the first megasonic emission rod 21 is 1.13 MHz, the megasonic frequency of the third megasonic emission rod 23 is 1.27 MHz, and the megasonic frequency of the second megasonic emission rod 22 is 0.69 MHz; the power of the first megasonic emission rod 21, the second megasonic emission rod 22 and the third megasonic emission rod 23 are all 2100 W.

[0037] During hot pressing, vacuum is first drawn to a vacuum degree of -60 mmHg, the temperature of the pressing plate is raised to 170°C, the pressure of the pressing plate on the prepreg is increased to 2.1 MPa, and then the heat and pressure are maintained and the megasonic vibration plate is started to apply megasonic vibration to the prepreg. After the megasonic vibration for 25 minutes, the megasonic vibration is stopped for 35 minutes, and then the megasonic vibration is continued for 60 minutes; thereafter, the megasonic vibration is stopped, the temperature is lowered to room temperature, and the vacuum is broken to obtain the salt spray resistant insulating material.

[0038] Step 5: After the hot pressing is completed, the mixture is cooled to room temperature to obtain the salt spray resistant insulating material.

[0039] Comparative Example 1

[0040] The only difference between this example and Example 2 is that the megasonic vibration plate is not started and megasonic vibration is not applied to the prepreg, and the rest are the same.

[0041] Comparative Example 2

[0042] The only difference between this example and Example 2 is that the first megaacoustic emission rod 21, the second megaacoustic emission rod 22 and the third megaacoustic emission rod 23 are all ultrasonic emission rods, the ultrasonic frequency is 20 kHz, and the power is 2100 W. The rest are the same.

[0043] Comparative Example 3

[0044] The difference between this example and Example 2 is that the first ultrasonic emitting rod is used to replace the first megasonic emitting rod 21, the second ultrasonic emitting rod is used to replace the second megasonic emitting rod 22, and the second ultrasonic emitting rod is used to replace the third megasonic emitting rod 23. The ultrasonic frequency of the first ultrasonic emitting rod is 32.8kHz, the ultrasonic frequency of the third ultrasonic emitting rod is 36.8kHz, and the ultrasonic frequency of the second ultrasonic emitting rod is 20kHz; the power of the first ultrasonic emitting rod, the second ultrasonic emitting rod and the third ultrasonic emitting rod are all 2100W. The rest are the same.

[0045] Comparative Example 4

[0046] The only difference between this example and Example 2 is that the megasonic frequencies of the first megasonic emission rod 21, the second megasonic emission rod 22 and the third megasonic emission rod 23 are all 1.13 MHz, and the rest are the same.

[0047] Comparative Example 5

[0048] The only difference between this example and Example 2 is that the megasonic frequencies of the first megasonic emission rod 21, the second megasonic emission rod 22 and the third megasonic emission rod 23 are all 0.69 MHz, and the rest are the same.

[0049] Comparative Example 6

[0050] The only difference between this example and Example 2 is that the megasonic frequencies of the first megasonic emission rod 21, the second megasonic emission rod 22 and the third megasonic emission rod 23 are all 1.03 MHz, and the rest are the same.

[0051] Comparative Example 7

[0052] The only difference between this example and Example 2 is that the megasonic frequencies of the first megasonic emission rod 21, the second megasonic emission rod 22 and the third megasonic emission rod 23 are all 1.03 MHz, the power of the first megasonic emission rod 21 is 1100 W, the power of the third megasonic emission rod 23 is 1300 W, the power of the second megasonic emission rod 22 is 700 W, and the rest are the same.

[0053] Comparative Example 8

[0054] The only difference between this example and Example 2 is that in step 4, after the pressure of the pressing plate on the prepreg is increased to 2.1 MPa, the heat and pressure are maintained and the megasonic vibration plate is started to apply megasonic vibration to the prepreg. After 50 minutes of megasonic vibration, the megasonic vibration is stopped for 10 minutes, and then the megasonic vibration is continued for 60 minutes; thereafter, the megasonic vibration is stopped, the temperature is lowered to room temperature, and the vacuum is broken; the rest are the same.

[0055] Comparative Example 9

[0056] The only difference between this example and Example 2 is that in step 4, after the pressure of the pressing plate on the prepreg is increased to 2.1 MPa, the heat and pressure are maintained and the megasonic vibration plate is started to apply megasonic vibration to the prepreg. After 120 minutes of megasonic vibration, the megasonic vibration is stopped, the temperature is lowered to room temperature, and the vacuum is broken; the rest are the same.

[0057] Comparative Example 10

[0058] The only difference between this example and Example 2 is that this example uses DOPO type benzoxazine resin instead of phenol type benzoxazine resin, and the rest is the same.

[0059] Acid salt spray resistance test

[0060] The test refers to GB / T10125-2012. The acidic salt spray consists of acetic acid, sodium chloride, copper chloride and water. The mass fraction of sodium chloride in the acidic salt spray is 4.75%, the mass fraction of acetic acid in the acidic salt spray is 0.2%, and the mass fraction of copper chloride in the acidic salt spray is 0.03%. After spraying in the salt spray aging chamber, the air pressure is maintained at 0.3MPa and the temperature is 50℃; the product to be tested is subjected to salt spray aging test with an aging cycle of 5d.

[0061] It is well known in the industry that during the salt spray aging period, the rapid increase in mass of epoxy resin insulation materials is caused by the accumulation of salt spray solution on the surface of the material and diffusion into the interior. Therefore, after the salt spray aging test, the more the insulation material gains weight and the shorter the time it takes to gain weight, the worse its salt spray resistance performance is.

[0062] Weight gain rate = the difference in mass of the insulating material before and after aging / the mass of the insulating material before aging.

[0063] The results of the "acid salt spray resistance test" in Example 2 and Comparative Examples 1 to 10 are shown in Table 1:

[0064] Table 1

[0065]

[0066] As can be seen from Table 1, the megasonic vibration plate 10 composed of three megasonic emission rods with different megasonic frequencies can effectively promote the compounding of the phenol-type benzoxazine resin with the reinforcing material during the hot pressing process by superimposed megasonic waves, thereby further reducing the pores in the insulating material, and the insulating material has a higher density, and is not only resistant to ordinary salt spray, but also has excellent salt spray resistance to acidic salt spray.

[0067] In the above embodiment, the first megaacoustic emission rod 21, the second megaacoustic emission rod 22 and the third megaacoustic emission rod 23 are all megaacoustic emission rods; the megaacoustic emission rods and ultrasonic emission rods are all purchased from Shijiazhuang Jingsuo Electronics Co., Ltd., which are special megaacoustic emission rods / ultrasonic emission rods for aluminum alloy degassing.

[0068] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A salt spray resistant insulating material, characterized in that: The reinforcing material is impregnated with a benzoxazine resin composition, the impregnated reinforcing material is dried to obtain a prepreg, and then the prepreg is sent to a vacuum hot press for hot pressing; during hot pressing, a megasonic vibration plate arranged in the vacuum hot press applies megasonic vibration to the prepreg; after the hot pressing is completed, the prepreg is cooled to room temperature to obtain the salt spray resistant insulating material.

2. The salt spray resistant insulating material according to claim 1, characterized in that: The megasonic vibration plate (10) is embedded in a pressing plate in a vacuum hot press, and a plurality of megasonic vibration plates (10) are provided; the megasonic vibration plate (10) comprises a metal plate body (10), a first megasonic emission rod (21), a second megasonic emission rod (22) and a third megasonic emission rod (23) are embedded in the metal plate body (10), the second megasonic emission rod (22) is located between the first megasonic emission rod (21) and the third megasonic emission rod (23), and portions of the first megasonic emission rod (21), the second megasonic emission rod (22) and the third megasonic emission rod (23) located outside the megasonic vibration plate (10) are cooled by cooling water.

3. The salt spray resistant insulating material according to claim 2, characterized in that: The megasonic frequency of the first megasonic emission rod (21) is 1.13 MHz, the megasonic frequency of the third megasonic emission rod (23) is 1.27 MHz, and the megasonic frequency of the second megasonic emission rod (22) is 0.69 MHz; the power of the first megasonic emission rod (21), the second megasonic emission rod (22) and the third megasonic emission rod (23) is 2100 W.

4. The salt spray resistant insulating material according to claim 1, characterized in that: The benzoxazine resin composition consists of 90 to 100 parts by weight of phenolic benzoxazine resin, 0.5 to 0.6 parts by weight of 2-methylimidazole and 8 to 10 parts by weight of butanone.

5. The salt spray resistant insulating material according to claim 2, characterized in that: During hot pressing, vacuum is first drawn to a vacuum degree of -60 mmHg, the temperature of the pressing plate is raised to 170-175°C, the pressure of the pressing plate on the prepreg is increased to 2.1-2.2 MPa, and then heat preservation and pressure maintenance are started and the megasonic vibration plate is started to apply megasonic vibration to the prepreg. After the megasonic vibration for 25 minutes, the megasonic vibration is stopped for 35 minutes, and then the megasonic vibration is continued for 60 minutes; thereafter, the megasonic vibration is stopped, the temperature is lowered to room temperature, and the vacuum is broken to obtain the salt spray resistant insulating material.

6. The salt spray resistant insulating material according to claim 1, characterized in that: The temperature for drying the impregnated reinforcement material is 155-165°C.

7. A method for preparing a salt spray resistant insulating material according to any one of claims 1 to 6, characterized in that: The following steps are involved: Step 1, preparing a benzoxazine resin composition in a stirred tank; Step 2, the benzoxazine resin composition is impregnated into the reinforcing material through a glue coating machine; Step 3, sending the impregnated reinforcement material into an oven for drying to obtain a prepreg; Step 4: After the prepreg is cut and stacked, it is placed in a mold and then sent to a vacuum hot press for hot pressing. During hot pressing, the megasonic vibration plate applies megasonic vibration to the prepreg. Step 5: After the hot pressing is completed, the mixture is cooled to room temperature to obtain the salt spray resistant insulating material.

8. An application of a salt spray resistant insulating material, characterized in that: The salt spray resistant insulating material according to any one of claims 1 to 6 is applied to electrical insulating materials resistant to acid salt spray.

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