Method for assessing the compatibility of butadiene-acrylonitrile rubber with synthetic esters
By measuring and analyzing the rate of change of refractive index between nitrile rubber and synthetic ester insulating liquid, the problem of lack of compatibility assessment in the existing technology was solved, and the compatibility assessment of key materials for oil-immersed transformers was realized, ensuring the safe and stable operation of the equipment.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- GUANGZHOU POWER SUPPLY BUREAU GUANGDONG POWER GRID CO LTD
- Filing Date
- 2023-10-10
- Publication Date
- 2026-07-07
Smart Images
Figure CN117434030B_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of power grid technology, and more specifically, to a method for evaluating the compatibility of nitrile rubber with synthetic esters. Background Technology
[0002] In the power grid sector, the compatibility of insulating fluid and structural materials in oil-immersed transformers not only affects the structural design and safe capacity of the transformers but also directly relates to the service life and safe, stable operation of electrical equipment. Synthetic ester insulating fluid in oil-immersed transformers primarily functions as insulation, cooling, and a carrier of status information; its ignition point is above 300℃, classifying it as a K-grade flame-retardant insulating material. Meanwhile, O-rings made of nitrile rubber are commonly used for sealing between the tank and bushings, as well as for sealing the tank itself. Therefore, nitrile rubber is one of the commonly used structural materials in oil-immersed transformers, and synthetic ester insulating fluid is one of the commonly used insulating fluids in oil-immersed transformers.
[0003] Therefore, determining the compatibility between nitrile rubber and synthetic ester insulating fluid plays an important role in designing the structure and safe capacity of oil-immersed transformers. However, there is currently no specific method or test procedure for evaluating the compatibility between nitrile rubber and synthetic ester insulating fluid. Summary of the Invention
[0004] In view of this, this application provides a method for evaluating the compatibility between nitrile rubber and synthetic ester, which is used to evaluate the compatibility between nitrile rubber and synthetic ester insulating liquid.
[0005] To achieve the above objectives, the following solution is proposed:
[0006] A method for evaluating the compatibility of nitrile rubber with synthetic esters includes:
[0007] Take a nitrile rubber sample, and clean and dry the nitrile rubber sample;
[0008] The synthetic ester insulating liquid is pretreated to ensure that its moisture content and breakdown voltage meet the test requirements.
[0009] The refractive index of the pretreated synthetic ester insulating liquid was measured, and the refractive index of the pretreated synthetic ester insulating liquid was used as the first index.
[0010] One portion of the pretreated synthetic ester insulating liquid was loaded into test container I, and the other portion of the pretreated synthetic ester insulating liquid was loaded into test container II.
[0011] The dried nitrile rubber sample was immersed in the synthetic ester insulating liquid in test container II;
[0012] Dry N2 was continuously blown into test container I and test container II until the blowing time met the time requirement, and test container I and test container II were then sealed.
[0013] Test container I and test container II after being heated and sealed;
[0014] The heated test containers I and II were cooled, and when they cooled to room temperature, the nitrile rubber sample was removed from test container II.
[0015] The refractive index of the synthetic ester insulating liquid in test container I after cooling was measured, and the refractive index of the synthetic ester insulating liquid in test container I was used as the second index.
[0016] The refractive index of the synthetic ester insulating liquid in test container II after the nitrile rubber sample was removed was measured, and the refractive index of the synthetic ester insulating liquid in test container II was used as the third index.
[0017] The compatibility of nitrile rubber with synthetic esters is evaluated based on the first index, the second index, and the third index.
[0018] Optionally, taking the nitrile rubber sample includes:
[0019] Unused blocks of nitrile rubber were cut into dumbbell shapes to obtain nitrile rubber samples.
[0020] Optionally, the cleaning and drying of the nitrile rubber sample includes:
[0021] Wipe the nitrile rubber sample with a non-woven cloth soaked in anhydrous ethanol;
[0022] The wiped nitrile rubber sample was placed in an oven at 105±5℃ and dried for 16 hours.
[0023] Optionally, the refractive index of the pretreated synthetic ester insulating liquid, the refractive index of the cooled synthetic ester insulating liquid in test container I, and the refractive index of the synthetic ester insulating liquid in test container II can be determined using an Abbe refractometer.
[0024] Optionally, the step of loading a portion of the pretreated synthetic ester insulating liquid into test container I and loading another portion of the pretreated synthetic ester insulating liquid into test container II includes:
[0025] Determine the surface area of the dried nitrile rubber sample;
[0026] Based on the surface area, determine the required volume of solution to be filled in test container II;
[0027] The pretreated synthetic ester insulating liquid, with a volume equal to the solution volume, was loaded into test container II;
[0028] The remaining pretreated synthetic ester insulating liquid was loaded into test container I.
[0029] Optionally, based on the surface area, the required volume of solution to be contained in test container II is determined, including:
[0030] Calculate the surface area and 65cm 2 The ratio;
[0031] Calculate the product of the ratio and 800 ml, and use the product as the volume of the solution.
[0032] Optionally, the heat-sealed test container I and test container II include:
[0033] The sealed test container I and test container II were placed in an oven at 120±2℃ and heated for 168N hours, where N is a positive integer not greater than 6.
[0034] Optionally, the assessment of the compatibility between nitrile rubber and synthetic esters based on the first index, the second index, and the third index includes:
[0035] Based on the first index, the second index and the third index, the rate of change of refractive index of the synthetic ester insulating liquid with the nitrile rubber sample placed on it is calculated.
[0036] The compatibility of nitrile rubber with synthetic esters is evaluated based on the refractive index change rate.
[0037] Optionally, the calculation of the refractive index change rate of the synthetic ester insulating liquid containing the nitrile rubber sample based on the first index, the second index, and the third index includes:
[0038] Substitute the first index, the second index, and the third index into the rate of change calculation function to calculate the rate of change of the refractive index of the synthetic ester insulating liquid with the nitrile rubber sample placed on it.
[0039] The function for calculating the rate of change can be shown below:
[0040]
[0041] ΔN is the rate of change of the refractive index; N se0 The first index; N se1 The second exponent; N se2 It is the third index.
[0042] Optionally, evaluating the compatibility of nitrile rubber with synthetic esters based on the refractive index change rate includes:
[0043] If the rate of change of the refractive index is less than 5%, then the nitrile rubber has good compatibility with the synthetic ester.
[0044] If the rate of change of the refractive index is not less than 5%, then the compatibility between nitrile rubber and synthetic ester is poor.
[0045] As can be seen from the above technical solution, the compatibility evaluation method for nitrile rubber and synthetic ester provided in this application can use the synthetic ester insulating liquid in the test container I as a blank control group, and evaluate the compatibility between nitrile rubber and synthetic ester insulating liquid by using the refractive index of the pretreated synthetic ester insulating liquid, the refractive index based on the blank control group, and the refractive index of the synthetic ester insulating liquid with the nitrile rubber sample placed on it.
[0046] In addition, the refractive index can be measured in real time. Therefore, this application can be used to monitor the compatibility changes between synthetic ester insulating liquid and nitrile rubber, thus achieving continuous monitoring.
[0047] Furthermore, the refractive index has high sensitivity, thus improving the sensitivity of monitoring changes in compatibility. Attached Figure Description
[0048] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of this application. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.
[0049] Figure 1 This is a flowchart of a method for evaluating the compatibility of nitrile rubber with synthetic esters disclosed in an embodiment of this application. Detailed Implementation
[0050] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.
[0051] For experiments not specifically described in this application, the procedures or conditions can be performed according to the conventional experimental procedures described in the literature in this field. Reagents or instruments whose manufacturers are not specified are all commercially available conventional reagent products.
[0052] Next, combine Figure 1 The method described in this application is detailed, including the following steps:
[0053] Step S1: Take a nitrile rubber sample, and clean and dry the nitrile rubber sample.
[0054] Specifically, nitrile rubber samples can be obtained for testing.
[0055] The nitrile rubber samples were cleaned with a volatile disinfectant solution and then dried.
[0056] Step S2: Pre-treat the synthetic ester insulating liquid to ensure that the moisture content and breakdown voltage of the synthetic ester insulating liquid meet the test requirements.
[0057] Specifically, the synthetic ester insulating liquid used for testing can be pretreated so that the moisture content and breakdown voltage of the pretreated synthetic ester insulating liquid meet the moisture content and breakdown voltage values specified in IEC 61099-2010.
[0058] Pretreatment may include methods such as filtration, water removal, and degassing.
[0059] Step S3: Measure the refractive index of the pretreated synthetic ester insulating liquid and use the refractive index of the pretreated synthetic ester insulating liquid as the first index.
[0060] Specifically, the refractive index of the pretreated synthetic ester insulating liquid can be measured, and the refractive index of the synthetic ester insulating liquid can be used as the first index.
[0061] The refractive index is an optical property of a material used to describe the speed of light as it travels through that material. It is the ratio of the speed of light when it enters the material from a vacuum or air to its speed of travel in the vacuum or air. The refractive index of different materials is one of their optical characteristics, and it is also the reason for phenomena such as refraction, reflection, and dispersion.
[0062] Step S4: Load a portion of the pretreated synthetic ester insulating liquid into test container I, and load the other portion of the pretreated synthetic ester insulating liquid into test container II.
[0063] Specifically, the pretreated synthetic ester insulating liquid can be divided into two parts, one part is put into test container I, and the other part is put into test container II.
[0064] Before filling the synthetic ester insulating liquid, test container I and test container II can be wiped with a volatile disinfectant solution, and then placed in an oven at 105±5℃ for 16 hours to dry.
[0065] Step S5: Immerse the dried nitrile rubber sample in the synthetic ester insulating liquid in test container II.
[0066] Specifically, the nitrile rubber sample can be immersed in the synthetic ester insulating liquid in test container II using tweezers.
[0067] Before handling the nitrile rubber sample, the tweezers can be wiped with a volatile disinfectant solution and then dried in an oven at 105±5℃ for 16 hours.
[0068] Step S6: Continuously blow dry N2 into test container I and test container II until the blowing time meets the time requirement, and then seal test container I and test container II.
[0069] Specifically, dry N2 can be continuously blown into test container I and test container II at a certain blowing rate until the blowing time meets the duration index, and then test container I and test container II are sealed.
[0070] The blowing rate can be set according to the actual test requirements.
[0071] The duration can also be set according to the actual experimental needs; for example, the duration can be 10 minutes.
[0072] Step S7: Test container I and test container II after heating and sealing.
[0073] Specifically, test container I and test container II can be placed in an oven for a preset heating time to heat them so that the temperature of test container I and test container II reaches the preset temperature range.
[0074] The heating time and temperature range can be set according to the actual test requirements.
[0075] Step S8: Cool the heated test container I and test container II, and when test container I and test container II have cooled to room temperature, remove the nitrile rubber sample from test container II.
[0076] Specifically, test container I and test container II can be removed from the oven, cooled to room temperature, and the nitrile rubber sample can be removed from test container II using tweezers.
[0077] Step S9: Measure the refractive index of the synthetic ester insulating liquid in the cooled test container I, and use the refractive index of the synthetic ester insulating liquid in the test container I as the second index.
[0078] Specifically, the refractive index of the synthetic ester insulating liquid in test container I can be measured, and the refractive index of the synthetic ester insulating liquid in test container I can be used as the second index.
[0079] Step S10: Measure the refractive index of the synthetic ester insulating liquid in test container II after the nitrile rubber sample is removed, and use the refractive index of the synthetic ester insulating liquid in test container II as the third index.
[0080] Specifically, the refractive index of the synthetic ester insulating liquid from the nitrile rubber sample can be used as the third index.
[0081] Step S11: Based on the first index, the second index and the third index, evaluate the compatibility between nitrile rubber and synthetic ester.
[0082] Specifically, the effects of nitrile rubber samples on synthetic ester insulating liquid can be determined using the first, second, and third indices.
[0083] The compatibility of nitrile rubber and synthetic ester was assessed based on the effect of nitrile rubber samples on synthetic ester insulating liquid.
[0084] As can be seen from the above technical solution, the compatibility evaluation method for nitrile rubber and synthetic ester provided in this application can use the synthetic ester insulating liquid in the test container I as a blank control group, and evaluate the compatibility between nitrile rubber and synthetic ester insulating liquid by using the refractive index of the pretreated synthetic ester insulating liquid, the refractive index based on the blank control group, and the refractive index of the synthetic ester insulating liquid with the nitrile rubber sample placed on it.
[0085] In addition, the refractive index can be measured in real time. Therefore, this application can be used to monitor the compatibility changes between synthetic ester insulating liquid and nitrile rubber, thus achieving continuous monitoring.
[0086] Furthermore, the refractive index has high sensitivity, thus improving the sensitivity of monitoring changes in compatibility.
[0087] Furthermore, measuring the refractive index is a non-contact testing method that does not require direct contact with the synthetic ester insulating liquid, thus avoiding damage or contamination of the synthetic ester insulating liquid.
[0088] In some embodiments of this application, the refractive index of the pretreated synthetic ester insulating liquid, the refractive index of the synthetic ester insulating liquid in test container I after cooling, and the refractive index of the synthetic ester insulating liquid in test container II can be determined using an Abbe refractometer.
[0089] In some embodiments of this application, the process of taking nitrile rubber samples in step S1 is described in detail, and the steps are as follows:
[0090] S10. Cut the unused block of nitrile rubber into dumbbell shapes to obtain nitrile rubber samples.
[0091] Specifically, unused blocks of nitrile rubber can be cut into dumbbell shapes as recommended in ISO 1817-2015 using scissors to form nitrile rubber samples.
[0092] Before cutting nitrile rubber, the nitrile rubber can be wiped with a volatile disinfectant solution, and the wiped scissors should be placed in an oven at 105±5℃ to dry for 16 hours.
[0093] As can be seen from the above technical solution, this embodiment provides an optional method for obtaining nitrile rubber samples, which can make the nitrile rubber samples more standardized.
[0094] In some embodiments of this application, the process of cleaning and drying the nitrile rubber sample in step S1 is described in detail, and the steps are as follows:
[0095] S11. Wipe the nitrile rubber sample with a non-woven cloth soaked in anhydrous ethanol.
[0096] Specifically, the volatile disinfectant solution can be anhydrous ethanol. For easy wiping, a non-woven cloth soaked in anhydrous ethanol can be used to wipe the nitrile rubber sample.
[0097] S12. Place the wiped nitrile rubber sample in an oven at 105±5℃ and dry for 16 hours.
[0098] Specifically, the wiped nitrile rubber sample can be placed in an oven at 105±5℃ and dried for 16 hours using tweezers.
[0099] As can be seen from the above technical solution, this embodiment provides an optional method for cleaning and drying nitrile rubber samples. The above method can further avoid errors and improve the reliability of the evaluation.
[0100] In some embodiments of this application, the process of step S4, which involves loading a portion of the pretreated synthetic ester insulating liquid into test container I and another portion of the pretreated synthetic ester insulating liquid into test container II, is described in detail below:
[0101] S40. Determine the surface area of the dried nitrile rubber sample.
[0102] Specifically, the volume of synthetic ester insulating liquid to be added to test container II is determined based on the matching standard between the surface area of the pre-placed nitrile rubber sample and the volume of the synthetic ester insulating liquid.
[0103] Among them, the above matching criteria can be determined according to the relevant regulations on compatibility assessment.
[0104] It can measure the surface area of dried nitrile rubber samples.
[0105] S41. Based on the surface area, determine the volume of solution to be filled into test container II.
[0106] Specifically, the volume of solution to be filled into test container II can be calculated based on the ratio and surface area.
[0107] S42. The pretreated synthetic ester insulating liquid with a volume equal to the solution volume is loaded into test container II.
[0108] Specifically, a synthetic ester insulating liquid with a matching solution volume can be loaded into test container II.
[0109] S43. Load the remaining pretreated synthetic ester insulating liquid into test container I.
[0110] Specifically, the remaining synthetic ester insulating liquid can be loaded into test container I.
[0111] As can be seen from the above technical solution, this embodiment provides an optional method for determining whether to add the synthetic ester insulating liquid into test container I and test container II respectively. The volume of the synthetic ester insulating liquid in test container II can match the surface area of the nitrile rubber sample, further standardizing the reaction process between nitrile rubber and synthetic ester insulating liquid.
[0112] In some embodiments of this application, the process of step S41, determining the volume of solution to be filled into test container II based on the surface area, is described in detail below:
[0113] S410, Calculate the surface area and 65cm² 2 The ratio of .
[0114] Specifically, it can be calculated by mixing 800ml of synthetic ester insulating liquid with a surface area of 65cm². 2 The nitrile rubber sample was matched to the standard, and the solution volume was calculated.
[0115] Specifically, the surface area of the nitrile rubber sample and 65 cm² can be calculated. 2 The ratio between them.
[0116] S411. Calculate the product between the ratio and 800ml, and use the product as the volume of the solution.
[0117] Specifically, the solution volume can be obtained by multiplying the ratio by 800 ml.
[0118] As can be seen from the above technical solution, this embodiment provides an optional method for calculating the solution volume, which can further improve the accuracy of the compatibility assessment in this application.
[0119] In some embodiments of this application, the processes of step S7, the heat-sealed test container I, and the test container II are described in detail below:
[0120] S70. Place the sealed test container I and test container II in an oven at 120±2℃ and heat for 168N hours, where N is a positive integer not greater than 6.
[0121] Specifically, the sealed test container I and test container II can be placed in an oven at 120±2℃ and heated for 168h to 1008h.
[0122] As can be seen from the above technical solution, this embodiment provides an optional method for heating test container I and test container II, which can further achieve the standardization of evaluation.
[0123] In some embodiments of this application, the process of evaluating the compatibility of nitrile rubber with synthetic ester based on the first index, the second index, and the third index is described in detail, and the steps are as follows:
[0124] S110. Based on the first index, the second index, and the third index, calculate the rate of change of refractive index of the synthetic ester insulating liquid on which the nitrile rubber sample is placed.
[0125] Specifically, the rate of change of refractive index of the synthetic ester insulating liquid containing the nitrile rubber sample can be calculated based on the first index, the second index, and the third index, compared to the synthetic ester insulating liquid in test container I.
[0126] S111. Based on the refractive index change rate, evaluate the compatibility between nitrile rubber and synthetic ester.
[0127] Specifically, the rate of change of the refractive index of the synthetic ester insulating liquid containing a nitrile rubber sample can be compared with a threshold to form a comparison result; based on the comparison result, the compatibility between nitrile rubber and synthetic ester can be evaluated.
[0128] As can be seen from the above technical solution, this embodiment provides an optional method for evaluating the compatibility of nitrile rubber and synthetic esters. Through the above method, the evaluation can be completed by comprehensively utilizing the first index, the second index, and the third index, further improving the reliability of this application.
[0129] In some embodiments of this application, the process of calculating the rate of change of refractive index of the synthetic ester insulating liquid containing the nitrile rubber sample in step S110, based on the first index, the second index, and the third index, is described in detail below:
[0130] S1100. Substitute the first index, the second index, and the third index into the rate of change calculation function to calculate the rate of change of the refractive index of the synthetic ester insulating liquid containing the nitrile rubber sample.
[0131] Specifically, the function for calculating the rate of change can be as follows:
[0132]
[0133] ΔN is the rate of change of the refractive index; N se0 The first index; N se1 The second exponent; N se2 It is the third index.
[0134] As can be seen from the above technical solution, this application can determine the rate of change of refractive index by determining the percentage difference between the second index and the third index relative to the first index, thereby further improving the accuracy of the evaluation in this application.
[0135] In some embodiments of this application, the process of evaluating the compatibility of nitrile rubber and synthetic ester based on the refractive index change rate is described in detail, and the steps are as follows:
[0136] S1110. If the rate of change of the refractive index is less than 5%, then the nitrile rubber has good compatibility with the synthetic ester.
[0137] Specifically, a threshold of 5% can be set to determine that the compatibility between nitrile rubber and synthetic ester is good when the rate of change of refractive index is less than 5%.
[0138] S1111 If the rate of change of the refractive index is not less than 5%, then the compatibility between nitrile rubber and synthetic ester is poor.
[0139] Specifically, when the rate of change of refractive index is not less than 5%, it is determined that the compatibility between nitrile rubber and synthetic ester is poor.
[0140] As can be seen from the above technical solution, this embodiment provides an optional method for evaluating the compatibility of nitrile rubber and synthetic esters based on the refractive index change rate, which can further improve the accuracy of this application.
[0141] Finally, it should be noted that in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.
[0142] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.
[0143] The above description of the disclosed embodiments enables those skilled in the art to make or use this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. The various embodiments of this application can be combined with each other. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims
1. A method for evaluating the compatibility of nitrile rubber with synthetic esters, characterized in that, include: Take a nitrile rubber sample, and clean and dry the nitrile rubber sample; The synthetic ester insulating liquid is pretreated to ensure that its moisture content and breakdown voltage meet the test requirements. The refractive index of the pretreated synthetic ester insulating liquid was measured, and the refractive index of the pretreated synthetic ester insulating liquid was used as the first index. Determine the surface area of the dried nitrile rubber sample; Based on the surface area, determine the required volume of solution to be filled in test container II; The pretreated synthetic ester insulating liquid, with a volume equal to the solution volume, was loaded into test container II; The remaining pretreated synthetic ester insulating liquid was loaded into test container I; The dried nitrile rubber sample was immersed in the synthetic ester insulating liquid in test container II; Dry N2 was continuously blown into test container I and test container II until the blowing time met the time requirement, and test container I and test container II were then sealed. Test container I and test container II after being heated and sealed; The heated test containers I and II were cooled, and when they cooled to room temperature, the nitrile rubber sample was removed from test container II. The refractive index of the synthetic ester insulating liquid in test container I after cooling was measured, and the refractive index of the synthetic ester insulating liquid in test container I was used as the second index. The refractive index of the synthetic ester insulating liquid in test container II after the nitrile rubber sample was removed was measured, and the refractive index of the synthetic ester insulating liquid in test container II was used as the third index. Substitute the first index, the second index, and the third index into the rate of change calculation function to calculate the rate of change of the refractive index of the synthetic ester insulating liquid with the nitrile rubber sample placed on it. If the rate of change of the refractive index is less than 5%, then the nitrile rubber has good compatibility with the synthetic ester. If the rate of change of the refractive index is not less than 5%, then the compatibility between nitrile rubber and synthetic ester is poor. The function for calculating the rate of change can be shown below: The rate of change of the refractive index; It is the first index; It is the second index; It is the third index.
2. The method for evaluating the compatibility of nitrile rubber with synthetic esters according to claim 1, characterized in that, The process of taking nitrile rubber samples includes: Unused blocks of nitrile rubber were cut into dumbbell shapes to obtain nitrile rubber samples.
3. The method for evaluating the compatibility of nitrile rubber with synthetic esters according to claim 1, characterized in that, The cleaning and drying of the nitrile rubber sample includes: Wipe the nitrile rubber sample with a non-woven cloth soaked in anhydrous ethanol; The wiped nitrile rubber sample was placed in an oven at 105±5℃ and dried for 16 h.
4. The method for evaluating the compatibility of nitrile rubber with synthetic esters according to claim 1, characterized in that, The refractive index of the pretreated synthetic ester insulating liquid, the refractive index of the synthetic ester insulating liquid in test container I after cooling, and the refractive index of the synthetic ester insulating liquid in test container II were determined using an Abbe refractometer.
5. The method for evaluating the compatibility of nitrile rubber with synthetic esters according to claim 1, characterized in that, Based on the surface area, determine the required volume of solution to be contained in test container II, including: Calculate the surface area and 65cm 2 The ratio; Calculate the product of the ratio and 800 ml, and use the product as the volume of the solution.
6. The method for evaluating the compatibility of nitrile rubber with synthetic esters according to claim 1, characterized in that, The heat-sealed test containers I and II include: The sealed test container I and test container II were placed in an oven at 120±2℃ and heated for 168×N hours, where N is a positive integer not greater than 6.