Self-sealing composite insulating material and preparation method thereof

Abstract

The invention discloses a self-sealing composite insulating material. The self-sealing composite insulating material structurally comprises a first resin layer, a first polyester non-woven fabric, a PET film layer, a second polyester non-woven fabric and a second resin layer from top to bottom in sequence. According to the invention, the epoxy resin with the epoxy equivalent of 180-190 g / eq and the polyester resin with the hydroxyl value of 615-620 KOH mg / g are reacted to prepare the insulating material with good sealing performance, the fluorinated liquid with the temperature of 80 DEG C and the purified water with the temperature of 90 DEG C can be prevented from entering a sealed space under the standard atmospheric pressure, and the sealing effect is good. The weight ratio of the bisphenol A epoxy resin to the saturated polyester resin is 4: (1-5), so that a good sealing effect of the composite insulating material is maintained, the composite insulating material also has good softness, and the composite insulating material is not easy to roll and warp after being used and cured and has excellent toughness.

Description

Technical Field

[0001] The invention relates to a self-sealing composite insulating material and a preparation method thereof, and relates to C08L, and in particular to the field of polymer compositions. Background Art

[0002] With the development of science and technology, the application of electricity is becoming more and more extensive, and the voltage in electrical cables is getting higher and higher, which puts higher requirements on the insulation and sealing performance of isolation materials. The application environment of isolation materials requires not only insulation performance, but also water-blocking and oil-blocking performance, especially in electrical components such as transformers or thermostats. The isolation effect of fluorinated liquid cannot be ignored. However, the existing sealing materials are expensive, and the sealing performance will decrease in high temperature environments. Therefore, it is very important to develop an insulation material with good sealing performance and self-sealing.

[0003] Chinese invention patent CN201810281766.X discloses an insulating sealing paint for electronic components with good heat dissipation, which uses a new type of material compounded with vinyl silicone oil, cresol, xylene and modified polyester resin, has good stability and heat resistance, high material density, high hardness after conjunctiva, and correspondingly high thermal conductivity, but the hardness of the composite material formed is high, and the sealing effect in electronic components is not good. Chinese invention patent CN201110037113.5 discloses an insulating waterproof epoxy resin composition and tape and a preparation method thereof, wherein the tape is respectively bonded to the epoxy resin composition layer on both sides of the high-strength soft breathable material layer, and the acrylate pressure-sensitive adhesive layer bonded to an epoxy resin composition layer, and the acrylate pressure-sensitive adhesive layer is covered with a protective release film or release paper. The prepared tape has the properties of heat resistance, waterproofness, good mechanical strength and good gloss, but the release layer needs to be peeled off during use, which will produce other waste. Summary of the invention

[0004] In order to improve the sealing effect of insulating materials in high temperature environments and reduce product costs, the first aspect of the present invention provides a self-sealing composite insulating material, the structure of the self-sealing composite insulating material includes, from top to bottom, a first resin layer, a first polyester non-woven fabric, a PET film layer, a second polyester non-woven fabric, and a second resin layer.

[0005] As a preferred embodiment, the thickness of the first polyester non-woven fabric layer is 0.03-0.1 mm, the thickness of the PET film layer is 0.1-0.2 mm, and the thickness of the second polyester non-woven fabric is 0.03-0.1 mm.

[0006] As a preferred embodiment, the thickness of the first polyester non-woven fabric layer is 0.05 mm, the thickness of the PET film layer is 0.125 mm, and the thickness of the second polyester non-woven fabric is 0.05 mm.

[0007] As a preferred embodiment, the raw materials for preparing the first resin layer and the second resin layer include, by weight: 30-50 parts of epoxy resin, 5-15 parts of curing agent, 20-40 parts of polyester resin, and 20-40 parts of solvent.

[0008] As a preferred embodiment, the epoxy resin is selected from one or a combination of glycidyl ether epoxy resin, glycidyl ester epoxy resin, glycidyl amine epoxy resin, and linear aliphatic epoxy resin.

[0009] As a preferred embodiment, the epoxy resin is a glycidyl ether epoxy resin.

[0010] As a preferred embodiment, the epoxy equivalent of the glycidyl ether epoxy resin is 180-190 g / eq, and the viscosity at 25° C. is 11000-15000 cps.

[0011] As a preferred embodiment, the curing agent is an amine curing agent, selected from one or a combination of aliphatic amines, alicyclic amines, aromatic amines, and polyamides.

[0012] As a preferred embodiment, the curing agent is an aromatic amine. More preferably, the curing agent is m-toluenediamine.

[0013] As a preferred embodiment, the polyester resin is a saturated polyester resin, and the number average molecular weight of the saturated polyester resin is 5-7×10 3 Da, glass transition temperature is 43-48°C.

[0014] As a preferred embodiment, the polyester resin is a saturated polyester resin, and the number average molecular weight of the saturated polyester resin is 6×10 3 Da, glass transition temperature is 46°C.

[0015] As a preferred embodiment, the acid value of the saturated polyester resin is 3-7 KOH mg / g, and the hydroxyl value is 615-620 KOH mg / g.

[0016] As a preferred embodiment, the acid value of the saturated polyester resin is 5KOH mg / g, and the hydroxyl value is 619KOH mg / g.

[0017] As a preferred embodiment, the weight ratio of the bisphenol A epoxy resin to the saturated polyester resin is 4:(1-5).

[0018] As a preferred embodiment, the weight ratio of the bisphenol A epoxy resin to the saturated polyester resin is 4:(2-4).

[0019] The applicant found in the experiment that an insulating material with good sealing performance can be prepared by reacting an epoxy resin with an epoxy equivalent of 180-190 g / eq with a polyester resin with a hydroxyl value of 615-620 KOH mg / g. The insulating material can prevent 80°C fluorinated liquid and 90°C pure water from entering the sealed space under standard atmospheric pressure, and has a good sealing effect. The possible reason is speculated to be: under the conditions of preferred epoxy equivalent and acid value, with the participation of a curing agent, bisphenol A epoxy resin and saturated polyester resin form a cross-linked network, and preliminary cross-linking occurs in the drying oven to form an insulating material with a soft material. After assembly, it is further baked and completely cured to form a cross-linked network with a high cross-linking density, and a tightly adherent metal material. Exceeding the preferred epoxy equivalent and acid value range, after preliminary curing, the hardness of the insulating material may be higher, causing curling problems during use. On the contrary, the sealing effect of the insulating material may be reduced and fail to meet the sealing requirements.

[0020] As a preferred embodiment, the solvent is selected from one or a combination of silicone oil, toluene, benzene, xylene, ethyl acetate, and cyclohexanone.

[0021] A second aspect of the present invention provides a method for preparing a self-sealing composite insulating material, comprising the following steps:

[0022] (1) coating a first resin layer on the upper surface of a first polyester nonwoven fabric, and coating a second resin layer on the lower surface of a second polyester nonwoven fabric;

[0023] (2) Place in a segmented temperature-controlled drying oven to undergo a preliminary cross-linking reaction and form a semi-cured resin coating on the surface;

[0024] (3) When in use, it is baked at high temperature for a short time to obtain a sealed composite insulating material.

[0025] As a preferred embodiment, the coating thickness of the first resin layer and the second resin layer are both 0.02-0.04 mm.

[0026] As a preferred embodiment, the segmented temperature-controlled drying tunnel is divided into three sections, the temperature of the first section is 110-120°C, the temperature of the second section is 120-130°C, and the temperature of the third section is 130-140°C.

[0027] As a preferred embodiment, each section of the segmented temperature-controlled drying tunnel is 4 m long, and the production speed is 7-8 m / min.

[0028] As a preferred embodiment, the high temperature baking temperature in step 3 is 180-200° C., and the baking time is 20-60 min.

[0029] The self-sealing composite insulating material of the present invention, the epoxy resin layer coated on the outer surface of the first polyester non-woven fabric and the second polyester non-woven fabric forms a semi-cured epoxy resin layer after step 2, which is used for the partition insulation between the iron shells of the temperature control protector, the inter-turn insulation of the coil wire of the special oil-immersed power transformer under high temperature environment, and the inter-layer insulation of the distribution transformer coil. After the high-temperature baking in step 3, the epoxy resin layer is completely cured, tightly adheres to the metal parts in contact with the composite material, and forms a sealing and insulating protection effect inside the iron shell of the temperature control protector, the inter-layer parts of the power transformer and the distribution transformer coil. The technical effect of preventing 80°C fluorinated liquid and 90°C pure water from entering the sealed space under standard atmospheric pressure can be achieved, and the sealing leakage rate is 2100ppm.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] (1) The sealing composite insulating material of the present invention can be prepared by reacting an epoxy resin having an epoxy equivalent of 180-190 g / eq with a polyester resin having a hydroxyl value of 615-620 KOH mg / g to obtain an insulating material with good sealing performance, which can prevent 80°C fluorinated liquid and 90°C pure water from entering the sealed space under standard atmospheric pressure, and has a good sealing effect.

[0032] (2) The sealing composite insulating material of the present invention has a weight ratio of bisphenol A epoxy resin to saturated polyester resin of 4:(1-5). While maintaining a good sealing effect of the composite insulating material, it also has good softness, is not prone to curling after curing, and has excellent toughness.

[0033] (3) The sealing composite insulating material of the present invention has a coating thickness of 0.02-0.04 mm for both the first resin layer and the second resin layer, so that it can be applied to a variety of small spaces to achieve a sealing effect and reduce costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is a schematic diagram of the side structure of the sealed composite insulating material of the present invention.

[0035] In the figure: 1. first resin layer; 2. first polyester non-woven fabric; 3. PET film layer; 4. second polyester non-woven fabric; 5. second resin layer. DETAILED DESCRIPTION

[0036] Example 1

[0037] A self-sealing composite insulating material, see Figure 1 The structure thereof includes, from top to bottom, a first resin layer, a first polyester non-woven fabric, a PET film layer, a second polyester non-woven fabric, and a second resin layer.

[0038] The thickness of the first polyester non-woven fabric layer is 0.05 mm, the thickness of the PET film layer is 0.125 mm, and the thickness of the second polyester non-woven fabric is 0.05 mm.

[0039] The raw materials for preparing the first resin layer and the second resin layer include, by weight: 40 parts of epoxy resin, 10 parts of curing agent, 30 parts of polyester resin, and 30 parts of solvent.

[0040] The epoxy resin is a glycidyl ether epoxy resin with an epoxy equivalent of 180-190 g / eq and a viscosity of 11000-15000 cps at 25° C. It is purchased from Shanghai Nanya New Materials Technology Co., Ltd. and has a model number of NPEL-128.

[0041] The curing agent is m-toluenediamine, which is purchased from Sinopec Baling Petrochemical Company.

[0042] The polyester resin is a saturated polyester resin with a number average molecular weight of 6×10 3 Da, glass transition temperature of 46 °C, acid value of 5 KOH mg / g, hydroxyl value of 619 KOH mg / g, purchased from Guangdong Yihao Chemical Technology Co., Ltd., model number AS9360.

[0043] The solvent is ethyl acetate.

[0044] A method for preparing a self-sealing composite insulating material comprises the following steps:

[0045] (1) coating a first resin layer on the upper surface of a first polyester nonwoven fabric, and coating a second resin layer on the lower surface of a second polyester nonwoven fabric;

[0046] (2) Place in a segmented temperature-controlled drying oven to undergo a preliminary cross-linking reaction and form a semi-cured resin coating on the surface;

[0047] (3) When in use, it is baked at high temperature for a short time to obtain a sealed composite insulating material.

[0048] The coating thickness of the first resin layer and the second resin layer is 0.03 mm. The segmented temperature-controlled drying tunnel is divided into three sections, the temperature of the first section is 115°C, the temperature of the second section is 125°C, and the temperature of the third section is 135°C.

[0049] Each section of the segmented temperature-controlled drying tunnel is 4 m long, and the production speed is 7 m / min.

[0050] The high temperature baking temperature in step 3 is 190° C. and the baking time is 30 minutes.

[0051] Example 2

[0052] A self-sealing composite insulating material comprises, from top to bottom, a first resin layer, a first polyester non-woven fabric, a PET film layer, a second polyester non-woven fabric, and a second resin layer.

[0053] The thickness of the first polyester non-woven fabric layer is 0.05 mm, the thickness of the PET film layer is 0.125 mm, and the thickness of the second polyester non-woven fabric is 0.05 mm.

[0054] The raw materials for preparing the first resin layer and the second resin layer include, by weight: 45 parts of epoxy resin, 12 parts of curing agent, 35 parts of polyester resin, and 40 parts of solvent.

[0055] The epoxy resin is a glycidyl ether epoxy resin with an epoxy equivalent of 180-190 g / eq and a viscosity of 11000-15000 cps at 25° C. It is purchased from Shanghai Nanya New Materials Technology Co., Ltd. and has a model number of NPEL-128.

[0056] The curing agent is 1,3-cyclohexanedimethylamine, which is purchased from Jining Tangyi Chemical Co., Ltd.

[0057] The polyester resin is a saturated polyester resin with a number average molecular weight of 6×10 3 Da, glass transition temperature of 46 °C, acid value of 5 KOH mg / g, hydroxyl value of 619 KOH mg / g, purchased from Guangdong Yihao Chemical Technology Co., Ltd., model number AS9360.

[0058] The solvent is ethyl acetate.

[0059] A method for preparing a self-sealing composite insulating material comprises the following steps:

[0060] (1) coating a first resin layer on the upper surface of a first polyester nonwoven fabric, and coating a second resin layer on the lower surface of a second polyester nonwoven fabric;

[0061] (2) Place in a segmented temperature-controlled drying oven to undergo a preliminary cross-linking reaction and form a semi-cured resin coating on the surface;

[0062] (3) When in use, it is baked at high temperature for a short time to obtain a sealed composite insulating material.

[0063] The coating thickness of the first resin layer and the second resin layer is 0.03 mm. The segmented temperature-controlled drying tunnel is divided into three sections, the temperature of the first section is 115°C, the temperature of the second section is 125°C, and the temperature of the third section is 135°C.

[0064] Each section of the segmented temperature-controlled drying tunnel is 4 m long, and the production speed is 7 m / min.

[0065] The high temperature baking temperature in step 3 is 190° C. and the baking time is 30 minutes.

[0066] Example 3

[0067] A self-sealing composite insulating material and a preparation method thereof, the specific steps are the same as those of Example 1, except that the epoxy resin is a glycidyl ether epoxy resin with an epoxy equivalent of 450-560 g / eq, purchased from Shanghai Zhengrui Chemical Co., Ltd., model E-20.

[0068] Example 4

[0069] A self-sealing composite insulating material and a preparation method thereof, wherein the specific steps are the same as those of Example 1, except that the raw materials for preparing the first resin layer and the second resin layer include, by weight, 40 parts of epoxy resin, 10 parts of curing agent, 10 parts of polyester resin, and 30 parts of solvent.

[0070] Performance Testing

[0071] 1. The self-sealing composite insulating material prepared in Examples 1-4 was placed between the iron shell and the metal cover plate, put into a mold for stamping, baked at 185°C for 30 minutes, and then a leakage test was performed. 10,000 finished products were placed in 90°C pure water, soaked for 1 minute, and observed whether bubbles emerged. Bubbles were leaking. Leakage rate = (number of bubbles / 10,000) × 100%.

[0072] 2. The dielectric constants of the self-sealing composite insulating materials prepared in Examples 1-4 were tested with reference to GB / T 7265.1-1987.

[0073] 3. The self-sealing composite insulating material prepared in Examples 1-4 was immersed in 80°C fluorinated liquid and 90°C pure water under standard atmospheric pressure for 10 hours. Whether there were continuous bubbles was observed within 1 minute. If there were no bubbles, it was determined that there was no leakage.

[0074] The test results are shown in Table 1.

[0075] Table 1

[0076]

[0077] *According to the general customer requirements of the industry, a leakage rate of less than 2000ppm can be considered qualified.

Claims

1. A self-sealing composite insulating material, characterized in that: The structure of the self-sealing composite insulating material comprises, from top to bottom, a first resin layer, a first polyester non-woven fabric, a PET film layer, a second polyester non-woven fabric, and a second resin layer.

2. The self-sealing composite insulating material according to claim 1, characterized in that: The thickness of the first polyester non-woven fabric layer is 0.03-0.1 mm, the thickness of the PET film layer is 0.1-0.2 mm, and the thickness of the second polyester non-woven fabric is 0.03-0.1 mm.

3. The self-sealing composite insulating material according to claim 1, characterized in that: The raw materials for preparing the first resin layer and the second resin layer include, by weight: 30-50 parts of epoxy resin, 5-15 parts of curing agent, 20-40 parts of polyester resin, and 20-40 parts of solvent.

4. The self-sealing composite insulating material according to claim 3, characterized in that: The epoxy resin is selected from one or a combination of glycidyl ether epoxy resin, glycidyl ester epoxy resin, glycidyl amine epoxy resin, and linear aliphatic epoxy resin.

5. The self-sealing composite insulating material according to claim 4, characterized in that: The epoxy equivalent of the glycidyl ether epoxy resin is 180-190 g / eq, and the viscosity at 25° C. is 11000-15000 cps.

6. The self-sealing composite insulating material according to claim 3, characterized in that: The curing agent is an amine curing agent, which is selected from one or a combination of aliphatic amines, alicyclic amines, aromatic amines, and polyamides.

7. The self-sealing composite insulating material according to claim 3, characterized in that: The polyester resin is a saturated polyester resin, and the number average molecular weight of the saturated polyester resin is 5-7×10 3 Da, glass transition temperature is 43-48°C.

8. The self-sealing composite insulating material according to claim 7, characterized in that: The saturated polyester resin has an acid value of 3-7 KOH mg / g and a hydroxyl value of 615-620 KOH mg / g.

9. A method for preparing the self-sealing composite insulating material according to any one of claims 1 to 8, characterized in that: The following steps are involved: (1) coating a first resin layer on the upper surface of a first polyester nonwoven fabric, and coating a second resin layer on the lower surface of a second polyester nonwoven fabric; (2) Place in a segmented temperature-controlled drying oven to undergo a preliminary cross-linking reaction and form a semi-cured resin coating on the surface; (3) When in use, it is baked at high temperature for a short time to obtain a sealed composite insulating material.

10. The method for preparing the self-sealing composite insulating material according to claim 9, characterized in that: Place The segmented temperature-controlled drying tunnel is divided into three sections, the temperature of the first section is 110-120°C, the temperature of the second section is 120-130°C, The temperature of the third stage is 130-140℃.

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