A sample preparation method and a test method for crosslinked gel breaking strength test
By preparing a cross-linked gel support structure on a vulcanized silicone rubber sheet and combining it with a specially designed electrode device, the problem of measuring the breakdown strength of gel-like materials with low cone penetration was solved, and efficient and accurate breakdown strength testing was achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- ZHEJIANG RONGTAI TECHNOLOGY ENTERPRISE CO LTD
- Filing Date
- 2023-02-16
- Publication Date
- 2026-06-05
AI Technical Summary
In the existing technology, gels with low cone penetration, such as silicone gels and polyurethane gels, are soft and lack rigidity, making it difficult to prepare 1mm thin sheets. This makes conventional dielectric strength testing methods unsuitable. Furthermore, oil cup electrode testing suffers from problems such as high sample consumption, difficult cleaning, the need for a large number of oil cups for batch testing, and the ease with which electrode oxidation can occur during the aging process.
A sample preparation method for crosslinked gel using a vulcanized silicone rubber sheet as a support includes making a hole in the center of the vulcanized silicone rubber sheet, pouring in uncured gel liquid and curing it to form a support structure, and then using a specially designed electrode device to perform a breakdown strength test.
This method enables simple measurement of cross-linked gels, improves measurement efficiency, reduces sample consumption and cleaning difficulty, avoids the defects of oil cup electrode testing, and ensures the accuracy of breakdown strength measurement.
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Figure CN116148025B_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of electrical performance testing of insulating materials, and in particular to a sample preparation method and testing method for cross-linked gel breakdown strength testing. Background Technology
[0002] Gel-like materials, such as silicone gels and polyurethane gels, especially those with low cone penetration, are generally too soft and lack rigidity to be prepared into 1mm thin sheets as used in conventional insulation material testing. Therefore, they are generally not suitable for conventional dielectric strength testing methods (GB / T1408-2016 Test Method for Electrical Strength of Insulating Materials). The usual testing method involves using an oil cup electrode test (GB / T507-2002 Determination of Breakdown Voltage of Insulating Oil). This involves pouring an uncrosslinked mixed adhesive solution into an oil cup containing electrodes, removing air bubbles, allowing it to solidify into a gel, and then testing its breakdown strength. This testing method has the following drawbacks: 1. It consumes a large amount of sample; 2. It is difficult to clean; 3. It requires a large number of oil cups for each batch of test samples; 4. If it is necessary to test the breakdown strength of the sample after aging, the oil cup and electrodes must be aged together, which may cause electrode oxidation and damage to the oil cup seal. Summary of the Invention
[0003] To address the aforementioned technical problems, this application provides a sample preparation method and a testing method for cross-linked gel breakdown strength testing.
[0004] Firstly, the sample preparation method for cross-linked gel breakdown strength testing provided in this application is achieved through the following technical solution:
[0005] A sample preparation method for crosslinked gel breakdown strength testing includes the following steps:
[0006] S1, to produce a thin sheet of vulcanized silicone rubber with a thickness of 2mm ± 0.2mm;
[0007] S2, make a round or square hole in the center of the vulcanized silicone rubber sheet;
[0008] S3, using a hard, smooth flat plate as the base plate and spraying a release agent, places the perforated vulcanized silicone rubber sheet from S2 onto the base plate;
[0009] S4, pour the uncured gel liquid into the openings of the vulcanized silicone rubber sheet, and cure it according to the curing conditions of the gel liquid; the gel liquid is one of silicone rubber or polyurethane gel;
[0010] S5. After the gel solution has cured, the silicone rubber sheet adheres to the gel, providing support for the gel. The silicone rubber sheet is then slowly peeled off from the base plate, thus completing the sample preparation.
[0011] By adopting the above technical solution, this application can prepare samples of gels that are difficult to form, making it easier to measure their breakdown strength and overcoming the difficulties existing in the prior art.
[0012] Preferably, the performance requirements of the vulcanized silicone rubber sheet are as follows: hardness controlled between 20 and 70 Shore A, tensile strength controlled between 2 and 10 MPa, and tear strength controlled between 6.0 and 25 N / mm.
[0013] By adopting the above technical solutions, the sample preparation operation can be effectively completed, and the quality of the sample preparation can be guaranteed.
[0014] Preferably, in step S2, a circular or square hole is made in the center of the vulcanized silicone rubber sheet. When a circular hole is made, the diameter of the circular hole is equal to 1.0 to 2.0 times the electrode diameter; when a square hole is made, the side length of the square hole is equal to 1.0 to 2.0 times the electrode diameter.
[0015] By adopting the above technical solutions, the sample preparation operation can be effectively completed, and the quality of the sample preparation can be guaranteed.
[0016] Preferably, the base plate is made of one of the following materials: PP plastic sheet, PC plastic sheet, PET plastic sheet, or steel.
[0017] By adopting the above technical solutions, the sample preparation operation can be effectively completed, and the quality of the sample preparation can be guaranteed.
[0018] Preferably, the test gel is a silicone gel, and the release agent is one of Jiadan special release agents JD-1016 and JD-008.
[0019] In this application, if the test gel is PU gel, there are no specific requirements for the release agent. However, if the test gel is silicone gel, the release agent needs to be optimized to ensure that the sample preparation operation can be effectively completed and the quality of the sample is guaranteed.
[0020] Preferably, in step S4, the uncured gel liquid is poured into the opening of the vulcanized silicone rubber sheet, and the liquid level of the gel liquid is flush with or slightly higher than the surface of the vulcanized silicone rubber sheet by 0.05-0.3 mm, and curing is completed according to the curing conditions of the gel liquid.
[0021] By adopting the above technical solutions, the sample preparation operation can be effectively completed, and the quality of the sample preparation can be guaranteed.
[0022] Secondly, the test method for sample preparation for cross-linked gel breakdown strength testing provided in this application is achieved through the following technical solution:
[0023] A test method for preparing a crosslinked gel breakdown strength test sample, the test equipment used in the test method includes a connecting rod, a first connecting electrode, a weight, a screw, a first spherical electrode, a second spherical electrode, a support, and a second connecting electrode, wherein the second spherical electrode is connected to the second connecting electrode; one end of the connecting rod is connected to the first connecting electrode, and the other end of the connecting rod is threadedly connected to the screw; the end of the screw facing away from the connecting rod is fixedly connected to the first spherical electrode; the weight is fixedly connected to the circumference of the connecting rod; a nut is fixedly connected to the circumference of the screw; the support is a thin sheet of vulcanized silicone rubber; the test method is as follows: first, adjust the height of the support to be flush with the height of the second spherical electrode, place the prepared sample on the support with the center of the gel part facing the second spherical electrode, lower the first connecting electrode until the distance between the first spherical electrode and the second spherical electrode is 1.0 mm, connect the first connecting electrode and the second connecting electrode to the test power supply, and test the breakdown strength of the prepared sample according to the voltage boosting method in GB / T 1408-2016 Electrical Strength Test Method for Insulating Materials.
[0024] This application enables the measurement of its breakdown strength, overcoming the difficulties existing in the prior art.
[0025] Preferably, the test method is as follows: First, adjust the height of the support to be level with the height of the second spherical electrode. Place the prepared sample on the support, with the center of the gel portion directly facing the second spherical electrode. Rotate the nut on the screw, and the first connecting electrode descends until the distance between the first and second spherical electrodes is 1.0 mm. Fix the nut on the screw, and the first spherical electrode is raised. Place the prepared sample in the center of the support, and lower the first spherical electrode. The gel between the first and second spherical electrodes is compressed to 1.0 mm. Connect the first and second connecting electrodes to the test power supply, and test the breakdown strength of the sample according to the voltage boosting method in GB / T 1408-2016 Test Method for Electrical Strength of Insulating Materials.
[0026] This application enables the measurement of its breakdown strength, overcoming the difficulties existing in the prior art.
[0027] In summary, this application has the following advantages:
[0028] 1. This application provides a simple device and method for measuring the breakdown strength of gel products. It uses a vulcanized silicone rubber sheet as a support frame, which enables the difficult-to-form gel to form a flat thin sheet. The breakdown strength of gel products can be measured by a specially designed electrode device.
[0029] 2. The sample preparation method in this application is relatively simple, which facilitates the improvement of the measurement efficiency of breakdown strength. Attached Figure Description
[0030] Figure 1 This is a schematic diagram of the test equipment used in the embodiments of this application.
[0031] In the figure, 1 is the first connecting electrode; 10 is the connecting rod; 2 is the weight; 3 is the screw; 31 is the nut; 4 is the first spherical electrode; 5 is the second spherical electrode; 6 is the support; and 7 is the second connecting electrode. Detailed Implementation
[0032] The present application will be further described in detail below with reference to the accompanying drawings and embodiments.
[0033] Example
[0034] A sample preparation method for crosslinked gel breakdown strength testing includes the following steps:
[0035] S1, to produce a thin sheet of vulcanized silicone rubber with a thickness of 2mm ± 0.2mm;
[0036] The performance requirements for vulcanized silicone rubber sheets are as follows: hardness controlled between 20 and 70 Shore A, tensile strength controlled between 2 and 10 MPa, and tear strength controlled between 6.0 and 25 N / mm.
[0037] In this embodiment, the performance requirements for the vulcanized silicone rubber sheet are as follows: hardness controlled between 45 Shore A, tensile strength controlled between 6 MPa, and tear strength controlled between 11 N / mm.
[0038] S2, make a round or square hole in the center of the vulcanized silicone rubber sheet;
[0039] When a circular hole is formed, the diameter of the circular hole is equal to 1.0 to 2.0 times the electrode diameter;
[0040] When a square hole is formed, the side length of the square hole is equal to 1.0 to 2.0 times the electrode diameter;
[0041] In this embodiment, a circular hole with a diameter of 2cm is made in the center of the vulcanized silicone rubber sheet.
[0042] S3, using a hard, smooth flat plate as the base, and spraying a release agent, the perforated vulcanized silicone rubber sheet from S2 is placed on the base plate; the base plate is made of one of the following materials: PP plastic sheet, PC plastic sheet, PET plastic sheet, or steel. In this embodiment, the base plate is made of PP plastic sheet; the release agent is one of Jiadan special release agent JD-1016 or JD-008, and in this embodiment, Jiadan special release agent JD-1016 is used;
[0043] S4. Pour the uncured gel into the openings of the vulcanized silicone rubber sheet. The level of the gel should be flush with or slightly higher than the surface of the silicone rubber sheet by 0.05-0.1 mm. Curing is then performed according to the gel curing conditions, specifically 25°C. The gel is either silicone rubber or polyurethane gel. In this embodiment, the uncured gel is silicone gel, specifically WACKER gel. 612A / Bx;
[0044] S5. After the gel solution has cured, the silicone rubber sheet adheres to the gel, providing support for the gel. The silicone rubber sheet is then slowly peeled off from the base plate, thus completing the preparation of the test sample.
[0045] A sample preparation method for testing the breakdown strength of cross-linked gels, including the sample preparation method and the testing equipment used in the method, is described in reference [reference needed]. Figure 1 The device includes a connecting rod 10, a first connecting electrode 1, a weight 2, a screw 3, a first spherical electrode 4, a second spherical electrode 5, a support 6, and a second connecting electrode 7. The second spherical electrode 5 and the second connecting electrode 7 are fixedly connected. One end of the connecting rod 10 is fixedly connected to the first connecting electrode 1, and the other end of the connecting rod 10 is threadedly connected to the screw 3. The end of the screw 3 facing away from the connecting rod 10 is fixedly connected to the first spherical electrode 4. The weight 2 is fixedly connected to the connecting rod 10 circumferentially. A nut 31 is fixedly connected to the screw 3 circumferentially for adjusting the distance between the first spherical electrode 4 and the second spherical electrode 5. The support 6 is a thin sheet of vulcanized silicone rubber. Specific testing method: First, adjust the height of the support 6 to be level with the height of the second spherical electrode 5. Place the sample prepared in this application on the support 6, with the center of the gel portion facing the second spherical electrode 5. Rotate the nut 31 on the screw 3, and the first connecting electrode 1 descends until the distance between the first spherical electrode 4 and the second spherical electrode 5 is 1.0 mm. Fix the nut 31 on the screw 3, and the first spherical electrode 4 is lifted. Place the prepared sample in the center of the support 6, and lower the first spherical electrode 4. The gel between the first spherical electrode 4 and the second spherical electrode 5 is compressed to 1.0 mm. Connect the first connecting electrode 1 and the second connecting electrode 7 to the test power supply. Test the breakdown strength of the sample according to the voltage boosting method in GB / T 1408-2016 Electrical Strength Test Method for Insulating Materials.
[0046] Using the test method of this application, the breakdown strength of the silicone gel is 16.78 kV / mm.
[0047] This application provides a simple device and method for measuring the breakdown strength of gel products. It uses a vulcanized silicone rubber sheet as a support frame, which enables the difficult-to-form gel to form a flat thin sheet. The breakdown strength of gel products can be measured by a specially designed electrode device.
[0048] Example 2
[0049] The difference between Example 2 and Example 1 is that the test object is Saint Kelly SK3317 polyurethane gel, which is cured at room temperature of 25°C. The release agent is Jiadan special release agent JD-1016. Using the test method of this application, the breakdown strength of the polyurethane gel is 21.02kV / mm.
[0050] Comparative Example
[0051] Comparative Example 1
[0052] The test method is to use an oil cup electrode test (GB / T507-2002 Insulating Oil Breakdown Voltage Determination Method), and test the uncrosslinked mixed adhesive solution (i.e., the silicone gel WACKER in Example 1). The 612A / Bx) was poured into an oil cup containing electrodes, air bubbles were removed, and the gel was solidified. Its breakdown strength was then tested. The breakdown strength of the silicone gel tested using the oil cup electrode was 16.82 kV / mm.
[0053] Comparative Example 2
[0054] The test method was to use an oil cup electrode test (GB / T507-2002 Insulating Oil Breakdown Voltage Test Method). The uncrosslinked mixed adhesive (i.e., the polyurethane gel in Example 2 - Saint Kelly SK3317 polyurethane gel) was poured into an oil cup containing electrodes, air bubbles were removed, and the gel was solidified and then its breakdown strength was tested. The breakdown strength of the silicone gel detected by the oil cup electrode test was 21.03 kV / mm.
[0055] Table 1 shows the breakdown strength data of the gels obtained by different test methods in Examples 1-2 and Comparative Examples 1-2.
[0056]
[0057] Note: Test error % = (Test reading of this application method - Test reading of oil cup electrode) * 100 / Test reading of oil cup electrode.
[0058] As can be seen from Examples 1-2 and Comparative Examples 1-2, and Table 1, the breakdown strength test error of the test method of this application is less than 0.5%, realizing the measurement of the breakdown strength of gel products. This overcomes the problems of the prior art, such as: 1. consuming a large amount of sample; 2. being difficult to clean; 3. requiring a large number of oil cups for batch testing samples; 4. if it is necessary to test the breakdown strength of the sample after aging, the oil cups and electrodes need to be aged together, which may cause problems such as electrode oxidation and oil cup seal damage. This specific embodiment is merely an explanation of this application and is not a limitation thereof. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but as long as they are within the scope of the claims of this application, they are protected by patent law.
Claims
1. A sample preparation method for cross-linked gel breakdown strength testing, characterized in that: Includes the following steps: S1, to produce a thin sheet of vulcanized silicone rubber with a thickness of 2mm ± 0.2mm; S2, make a round or square hole in the center of the vulcanized silicone rubber sheet; S3, using a hard, smooth flat plate as the base plate and spraying a release agent, places the perforated vulcanized silicone rubber sheet from S2 onto the base plate; S4, pour the uncured gel liquid into the openings of the vulcanized silicone rubber sheet, and cure it according to the curing conditions of the gel liquid; the gel liquid is one of silicone rubber or polyurethane gel; S5. After the gel solution has cured, the silicone rubber sheet adheres to the gel, providing support for the gel. The silicone rubber sheet is then slowly peeled off from the base plate, thus completing the sample preparation.
2. The sample preparation method for cross-linked gel breakdown strength testing according to claim 1, characterized in that: The performance requirements for the vulcanized silicone rubber sheet are as follows: hardness controlled between 20 and 70 Shore A, tensile strength controlled between 2 and 10 MPa, and tear strength controlled between 6.0 and 25 N / mm.
3. The sample preparation method for cross-linked gel breakdown strength testing according to claim 1, characterized in that: In step S2, a circular or square hole is made in the center of the vulcanized silicone rubber sheet. When a circular hole is made, the diameter of the circular hole is equal to 1.0 to 2.0 times the electrode diameter; when a square hole is made, the side length of the square hole is equal to 1.0 to 2.0 times the electrode diameter.
4. The sample preparation method for cross-linked gel breakdown strength testing according to claim 1, characterized in that: The base plate is made of one of the following materials: PP plastic sheet, PC plastic sheet, PET plastic sheet, or steel.
5. The sample preparation method for cross-linked gel breakdown strength testing according to claim 1, characterized in that: When the test gel is a silicone gel, the release agent is one of Jiadan Special Release Agent JD-1016 or JD-008.
6. The sample preparation method and testing method for cross-linked gel breakdown strength testing according to claim 1, characterized in that: In step S4, the uncured gel liquid is poured into the opening of the vulcanized silicone rubber sheet. The liquid level of the gel liquid is flush with or slightly higher than the surface of the vulcanized silicone rubber sheet by 0.05-0.3 mm, and curing is completed according to the curing conditions of the gel liquid.
7. A test method for a sample prepared by the sample preparation method for the crosslinked gel breakdown strength test according to any one of claims 1-6, characterized in that: The testing equipment used in the test method includes a connecting rod (10), a first connecting electrode (1), a weight (2), a screw (3), a first spherical electrode (4), a second spherical electrode (5), a bracket (6), and a second connecting electrode (7). The second spherical electrode (5) is connected to the second connecting electrode (7). One end of the connecting rod (10) is connected to the first connecting electrode (1), and the other end of the connecting rod (10) is threadedly connected to the screw (3). The end of the screw (3) facing away from the connecting rod (10) is fixedly connected to the first spherical electrode (4). The weight (2) is fixedly connected to the first spherical electrode (4). The connecting rod (10) is circumferentially connected; the screw (3) is circumferentially fixedly connected with a nut (31); the bracket (6) is a vulcanized silicone rubber sheet as described in any one of claims 1-6; the test method is as follows: first, adjust the height of the bracket (6) to be flush with the height of the second spherical electrode (5), place the prepared sample on the bracket (6), with the center of the gel part facing the second spherical electrode (5), lower the first connecting electrode (1) until the distance between the first spherical electrode (4) and the second spherical electrode (5) is 1.0 mm, connect the first connecting electrode (1) and the second connecting electrode (7) to the test power supply, and test the breakdown strength of the sample according to the voltage boosting method in GB / T 1408-2016 Electrical Strength Test Method for Insulating Materials.
8. The test method for the sample prepared by the sample preparation method for cross-linked gel breakdown strength testing according to claim 7, characterized in that: The test method is as follows: First, adjust the height of the support (6) to be level with the height of the second spherical electrode (5), place the prepared sample on the support (6), the height of the support (6) is level with the height of the second spherical electrode (5), place the prepared sample on the support (6), and the center of the gel part is directly facing the second spherical electrode (5). Rotate the nut (31) on the screw (3), and the first connecting electrode (1) descends to the distance between the first spherical electrode (4) and the second spherical electrode (5) is 1.0 mm. Fix the nut (31) on the screw (3), and the first spherical electrode (4) is lifted up. Place the prepared sample in the center of the support (6), and the first spherical electrode (4) is lowered. The gel between the first spherical electrode (4) and the second spherical electrode (5) is squeezed to become 1.0 mm. The first connecting electrode (1) and the second connecting electrode (7) are connected to the test power supply. According to the voltage boosting method in GB / T 1408-2016 Electrical Strength Test Method for Insulating Materials, the breakdown strength of the sample is tested.