Evaluation method

Abstract

A testing device 10 performs a first step for applying a load to a polymer material, a measurement device 20 performs a second step for measuring the amount of chemiluminescence emitted from the polymer material, and an evaluation device 30 performs a third step for calculating the durability of the polymer material on the basis of the magnitude of the amount of chemiluminescence.

Description

Evaluation Method

[0001] The present disclosure relates to an evaluation method.

[0002] Compared with inorganic compounds such as metals, ceramics, and glass, polymer materials are more likely to deteriorate and have inferior durability. For example, a living hinge having an opening and closing structure is composed of a polymer material with high flexibility and large elongation at break, such as polypropylene or polyethylene.

[0003] Therefore, products made of polymer materials must consider deterioration such as photooxidation and bending. Thus, there is a technique for evaluating the durability of polymer materials (see Non-Patent Documents 1 to 7).

[0004] Oishi, "Degradation Analysis, Durability Evaluation, and Life Prediction Supporting the Reliability of Polymer Materials", Polymer, Vol. 48, November issue, 1999, pp. 838 - pp. 841 Mikawa, et al. 5 names, "Comparison of Degradation Behavior of Low-Density Polyethylene by Weathering Testing Machines", Materials and Environment, 64, 2015, pp. 139 - pp. 144 "Method for Obtaining Exposure Environments for the Weather Resistance of Plastics Using Polyethylene Reference Test Specimens (Revised as of April 1, 2009)", Japan Weathering Test Center, JWTCS4002:2009 Yokoi, et al. 1 name, "Effect of Improving Hinge Characteristics by In-Mold Insert Hinge Molding", Production Research 393, Vol. 42, No. 6, June 1990, pp. 97 - pp. 100 Kaori Negishi, et al. 5 names, "Microscopic Analysis of Degraded Living Hinges of Polypropylene Aerial Cable Closure", Materials and Environment, Vol. 72, No. 3, May 2023, pp. 76 - pp. 84 "Environmental Stress Cracking of Plastics", Osaka Institute of Industrial Technology, Technical Sheet, NO. 98037 Sato, et al. 1 name, "Recent Trends in High-Sensitivity Chemiluminescence Measurement Methods - From Detection of Minute Oxidation of Resins to Curing Reactions -", Journal of the Adhesion Society of Japan, Vol. 55, No. 6, 2019, pp. 236 - pp. 245

[0005] However, there is a problem that the evaluation calculation of the durability of polymer materials takes time.

[0006] This disclosure is made in view of the above circumstances, and the purpose of this disclosure is to provide a technology that can improve the total test time for evaluating the durability of polymer materials.

[0007] An evaluation method according to one aspect of the present disclosure includes a first step in which a test device applies a load to a polymer material, a second step in which a measuring device measures the amount of chemiluminescence emitted from the polymer material, and a third step in which an evaluation device calculates the durability of the polymer material based on the magnitude of the amount of chemiluminescence.

[0008] According to this disclosure, the total testing time required for evaluating the durability of polymer materials can be reduced.

[0009] Figure 1 shows an example of the configuration of the durability evaluation system according to the first embodiment. Figure 2 shows an example of a polymer material. Figure 3 shows an example of measuring the amount of chemiluminescence emission and the integrated amount of chemiluminescence emission. Figure 4 shows an example of the operation of the durability evaluation system according to the first embodiment. Figure 5 shows the evaluation results of the degradation resistance performance according to the first embodiment. Figure 6 shows an example of the bending angle of the polymer material. Figure 7 shows an example of the operation of the durability evaluation system according to the second embodiment. Figure 8 shows the evaluation results of the degradation resistance performance according to the second embodiment. Figure 9 shows an example of the operation of the durability evaluation system according to the third embodiment. Figure 10 shows the evaluation results of the degradation resistance performance according to the third embodiment. Figure 11 shows an example of the configuration of the durability evaluation system according to the fourth embodiment. Figure 12 shows an example of the operation of the durability evaluation system according to the fourth embodiment. Figure 13 shows the evaluation results of the degradation resistance performance according to the fourth embodiment. Figure 14 shows an example of the hardware configuration of the evaluation device.

[0010] Embodiments of this disclosure will be described below with reference to the drawings. In the drawings, the same parts are denoted by the same reference numerals and their descriptions are omitted.

[0011] [Summary of this disclosure] This disclosure evaluates the durability of a polymer material by subjecting it to a load and degradation, and then evaluating the durability based on the amount of chemiluminescence emitted from the polymer material. For example, a polymer material is photo-oxidatively degraded by light irradiation, the amount of peroxide generated by the emission of light on the surface of the polymer material is measured, and the durability is evaluated based on the magnitude of that amount.

[0012] In other words, radicals generated in polymer materials by light, heat, etc., react with oxygen in the air to form peroxide radicals. The light emitted when the excited carbonyl and singlet oxygen generated by the bimolecular reaction of the peroxide radicals return to the ground state is detected.

[0013] In this way, by utilizing the amount of chemiluminescence emitted from degraded polymer materials, it is possible to detect the initial stages of degradation of polymer materials. Therefore, the total testing time for evaluating the durability of polymer materials can be shortened. Furthermore, since the amount of chemiluminescence is measured as a numerical value, the degree of oxidation, durability, and degradation of polymer materials can be quantitatively evaluated.

[0014] [First Embodiment] In the first embodiment, a case in which a polymer material is degraded by subjecting it to environmental stress will be described.

[0015] (Example of Durability Evaluation System Configuration) Figure 1 is a diagram showing an example of the configuration of a durability evaluation system according to the first embodiment. The durability evaluation system 1 comprises a test device 10, a measuring device 20, and an evaluation device 30.

[0016] The test apparatus 10 is an accelerated weathering test apparatus designed to simulate the degradation of polymer materials due to degradation factors in the outdoor environment. For example, the test apparatus 10 is capable of performing tests in accordance with ISO 11341, JIS K 5600-7-7, JIS K 7350-2, etc.

[0017] Specifically, the test apparatus 10 applies environmental and stress loads to the polymer material. Environmental loads include, for example, light, heat, water, and chemicals. Stress loads include, for example, bending stress, tensile stress, compressive stress, and torsional stress. One or more types of loads are sufficient to be applied to the polymer material.

[0018] Such a test apparatus 10 includes a simulated sunlight light source, a heat source, a water source, a chemical solution input source, a temperature control function, a humidity control function, a bending stress application mechanism, a tensile stress application mechanism, a compressive stress application mechanism, and a torsional stress application mechanism. These structures are arbitrary.

[0019] For example, let's explain light sources.

[0020] The light source emits light in the ultraviolet, visible, and infrared regions. Examples include ultraviolet fluorescent lamps, xenon lamps, sunshine carbon lamps, and metal halide lamps. Xenon lamps are preferred because their spectrum is similar to sunlight and they can accelerate degradation. If further acceleration of degradation is desired, ultraviolet fluorescent lamps and metal halide lamps are also suitable.

[0021] A filter may be placed near the light source to make the spectral radiation distribution of the light source closer to that of sunlight. Sunlight may be used instead of a light source, but since this takes a long time for the polymer material to degrade, it is preferable to combine it with a chemical solution that can accelerate degradation.

[0022] Next, the measuring device 20 will be described.

[0023] The measuring device 20 is a device that measures the amount of chemiluminescence emitted from the surface of a polymer material that has been degraded in the test device 10.

[0024] In particular, the measuring device 20 measures the amount of chemiluminescence emitted when the polymer material is placed in an inert atmosphere and within the temperature at which the surface reaction occurs, in order to further accelerate degradation and improve the detection accuracy of chemiluminescence emission.

[0025] Next, the evaluation device 30 will be described.

[0026] The evaluation device 30 is a device that evaluates the durability (degradation life, etc.) of polymer materials based on the magnitude of the chemiluminescence emission or the magnitude of the integrated emission. For example, when the amount of light emitted from the surface of multiple polymer materials that have been photo-oxidized and degraded under the same conditions is measured under the same conditions using the chemiluminescence method, polymer materials with lower emission amounts are evaluated as having higher degradation resistance.

[0027] Such an evaluation device 30 includes, for example, a processing unit 31, an output unit 32, and a storage unit 33.

[0028] The processing unit 31 has a function to evaluate and calculate the durability of the polymer material based on the magnitude of the chemiluminescence emission measured by the measuring device 20.

[0029] Furthermore, the processing unit 31 is equipped with a function to evaluate and calculate the durability of the polymer material based on the magnitude of the cumulative chemiluminescence emission amount (total amount) measured within a predetermined time, in order to improve the accuracy of durability evaluation.

[0030] The output unit 32 has a function to output the evaluation results of the durability of the polymer material.

[0031] The memory unit 33 has a function to store the evaluation results of the durability of polymer materials.

[0032] Next, we will explain specific examples of each device.

[0033] Existing accelerated weathering test equipment can be used as the test apparatus 10.

[0034] For example, a chemiluminescence analyzer can be used as the measuring device 20 and the evaluation device 30. A chemiluminescence analyzer is a device that measures the amount of chemiluminescence emitted using a known method such as JIS K7351. A computer may also be used in combination. In this case, the chemiluminescence analyzer corresponds to the measuring device 20, and the computer corresponds to the evaluation device 30.

[0035] (Polymer materials) Next, we will explain polymer materials.

[0036] The polymer material is, for example, an olefin-based polymer material that includes a living hinge structure. A living hinge structure is a structure in which two members are connected by a thin component, allowing the two members to be opened and closed.

[0037] For example, as shown in Figure 2, there is a first polymer material 100a in the shape of a strip measuring 2 cm × 5 cm that includes a linear living hinge structure indicated by a dashed line, a second polymer material 100b measuring 2 cm × 2 cm that is cut out from the first polymer material 100a so as to include the living hinge structure, and a third polymer material 100c that is cut out in the shape of a dumbbell that includes the living hinge structure.

[0038] For example, polymer materials are used in resin caps for mayonnaise containers and hand cream containers, and consist of lids and lid seats formed from thin, flexible resin in substantially the same shape, as well as thin resin members that connect the lids and lid seats.

[0039] Furthermore, if the polymer material test specimen has a hinge portion, it is preferable that the short side of the test specimen and the hinge portion are parallel. It is preferable that the thickness of the polymer material be uniform across the entire plane excluding the hinge portion. In the first embodiment, since only environmental burden is placed on the polymer material, it is not necessary to include a living hinge structure.

[0040] (Example of operation of the durability evaluation system) Next, an example of operation of the durability evaluation system 1 will be explained.

[0041] (Procedure 1) An accelerated weathering test of the polymer material is performed in the test apparatus 10 under pre-set conditions.

[0042] For example, to comply with JIS K5600-7-7 and JIS K7350-2, the conditions inside the tank are set to "black panel temperature: 63°C, temperature: 38°C, humidity: 50%RH, water spray time: 18 minutes out of 2 hours, light irradiation intensity: ultraviolet radiation intensity of 60W / m² with wavelengths of 300nm to 400nm". 2 The settings are configured as follows. Then, the polymer material to be evaluated is placed in the tank and accelerated degradation is performed for 1000 hours.

[0043] (Procedure 2) Using the measuring device 20, the amount of chemiluminescence emitted from the surface of the polymer material that has undergone the various degradations described above is measured.

[0044] When measuring the luminescence amount of chemiluminescence, it is preferable to place the polymer material in an inert atmosphere. The inert atmosphere is, for example, a space filled with an inert gas such as nitrogen gas or argon gas.

[0045] Also, when measuring the luminescence amount of chemiluminescence, it is preferable to place the polymer material within the temperature range where surface reaction occurs. For example, the measurement is performed while the polymer material is placed within a constant temperature range of 80°C to 200°C or during the heating process.

[0046] As the temperature adjustment means, any device that can heat the inside of the container storing the polymer material may be used. For example, it is a heater that can heat to a temperature above the temperature at which surface reaction occurs on the surface of the polymer material. Regarding the temperature conditions, they may be appropriately set, such as a constant temperature or a heating process.

[0047] (Step 3) By continuously measuring with the measuring device 20, a luminescence curve regarding the luminescence amount of chemiluminescence can be obtained. This luminescence curve is a spectrum obtained by measuring the luminescence amount when the excited carbonyl and singlet oxygen generated due to the oxygen deterioration on the surface of the polymer material return to the ground state.

[0048] As shown in FIG. 3, the luminescence amount of chemiluminescence has a maximum peak at a specific time due to oxides or the like on the surface of the polymer material, and then decreases to a constant value. Therefore, by continuously measuring the luminescence amount until it reaches a constant value and integrating the luminescence amount over the measurement time, the integrated luminescence amount of chemiluminescence can be obtained. If the integrated luminescence amount is below a certain amount, it can be evaluated as having high weather resistance.

[0049] Therefore, in the evaluation device 30, the integrated luminescence amount is calculated using the luminescence amount of chemiluminescence measured until it reaches a constant value. If the integrated luminescence amount is below a certain amount, it is determined that the durability (weather resistance) of the polymer material to be evaluated is high, and if the integrated luminescence amount is greater than a certain amount, it is determined that the durability (weather resistance) of the polymer material to be evaluated is low.

[0050] (Operation Example of Durability Evaluation System) FIG. 4 is a diagram showing an operation example of the durability evaluation system according to the first embodiment.

[0051] The test apparatus 10 irradiates each polymer material test specimen with ultraviolet light emitted from a xenon lamp for 1000 hours (steps S101, S102).

[0052] The weathering test duration may be shorter than 1000 hours. Depending on the test specimen, due to the effects of weathering agents, etc., sufficient degradation may not begin after 1000 hours in terms of detecting chemiluminescence emission. Therefore, the duration should be set to a time sufficient for degradation to begin, depending on the material, size, shape, etc., of the test specimen.

[0053] Next, the measuring device 20 places each test specimen in a chamber (JIS K7351) set to a nitrogen gas atmosphere and a constant temperature of 160°C, and measures the amount of chemiluminescence emitted from the surface of each test specimen for 10 minutes (step S103).

[0054] Next, the evaluation device 30 calculates the cumulative luminescence amount of chemiluminescence measured over 10 minutes (step S104).

[0055] Next, the evaluation device 30 determines whether the cumulative emission amount of chemiluminescence is 600,000 counts or less (step S105).

[0056] Finally, the evaluation device 30 determines that the degradation resistance performance is sufficient for test specimens with an integrated luminescence amount of 600,000 counts or less (step S106), and for test specimens with an integrated luminescence amount greater than 600,000 counts, it determines that the degradation resistance performance is insufficient (step S107).

[0057] Figure 5 shows the evaluation results of the degradation resistance performance of samples I to IV of the four test specimens. Sample I was judged to have insufficient degradation resistance because its cumulative chemiluminescence emission was greater than 600,000 counts. Samples II to IV were judged to have sufficient degradation resistance because their cumulative emitting emissions were 600,000 counts or less.

[0058] (Effects of the First Embodiment) According to the first embodiment, the test apparatus 10 degrades the polymer material by applying an environmental load, the measuring device 20 measures the amount of chemiluminescence emitted from the degraded polymer material, and the evaluation device 30 calculates the durability of the polymer material based on the magnitude of the cumulative amount of chemiluminescence emitted within a predetermined time. This makes it possible to capture the initial stage of degradation of the polymer material and shorten the total test time for evaluating the durability of the polymer material.

[0059] Furthermore, according to the first embodiment, since the amount of chemiluminescence light emitted is measured, the degree of oxidation, durability, and degradation of the polymer material can be quantitatively evaluated.

[0060] (Note) The evaluation device 30 may evaluate the durability of the polymer material based on the amount of chemiluminescence emission, rather than the cumulative amount of chemiluminescence emission. Since the amount of chemiluminescence emission is used in the same way, the same effect as when using the cumulative amount of chemiluminescence emission can be obtained.

[0061] [Second Embodiment] The chemiluminescence method for evaluating degradation resistance can be used not only for photo-oxidative degradation but also for degradation due to bending, etc. Therefore, in the second embodiment, a case in which a polymer material is degraded by applying stress load will be described.

[0062] The configuration of the durability evaluation system is the same as in the first embodiment. The test apparatus 10 is a device that applies stress load to a polymer material. For example, the test apparatus 10 is a device capable of performing tests in accordance with JIS P8115, JIS-K5600, JIS C 3005, etc.

[0063] For example, the test apparatus 10 bends the polymer material at a predetermined bending angle and number of bends. For example, each polymer material is bent at 0 degrees, 30 degrees, 50 degrees, 90 degrees, 120 degrees, 10 times, and 30 times. The bending angle is the angle formed when the two members 101 and 102 constituting the polymer material 100 are bent in a living hinge structure, as shown in Figure 6.

[0064] The evaluation device 30 evaluates the durability of a polymer material after it has been subjected to stress loading, based on the magnitude of the chemiluminescence emitted from the surface of the polymer material or the magnitude of the integrated chemiluminescence emitted.

[0065] For example, the evaluation device 30 determines the cumulative chemiluminescence emission amount for multiple polymer materials that have been degraded by bending under the same conditions using the chemiluminescence method, and evaluates polymer materials with lower cumulative chemiluminescence emission amounts as having higher degradation resistance.

[0066] The stress load may be applied manually by the user, rather than by the test device 10.

[0067] Figure 7 shows an example of operation of the durability evaluation system according to the second embodiment.

[0068] The test apparatus 10 bends each polymer material test specimen to 50 degrees 1000 times (step S201). The bending angle and number of bends are preferably set to conform to the usage environment of the polymer material.

[0069] Steps S202 to S206 shown in Figure 7 are the same as steps S103 to S107 shown in Figure 4.

[0070] Figure 8 shows the evaluation results of the degradation resistance performance of samples I to IV of the four test specimens. Sample II was judged to have insufficient degradation resistance because its cumulative chemiluminescence emission was greater than 600,000 counts. Samples I, III, and IV were judged to have sufficient degradation resistance because their cumulative chemiluminescence emission was 600,000 counts or less.

[0071] According to the second embodiment, the test apparatus 10 applies stress load to the polymer material to degrade it, the measuring device 20 measures the amount of chemiluminescence emitted from the degraded polymer material, and the evaluation device 30 calculates the durability of the polymer material based on the magnitude of the cumulative amount of chemiluminescence emitted within a predetermined time. This makes it possible to capture the initial stage of degradation of the polymer material and shorten the total test time for evaluating the durability of the polymer material.

[0072] Furthermore, according to the second embodiment, since the amount of chemiluminescence light emitted is measured, the degree of oxidation, durability, and degradation of the polymer material can be quantitatively evaluated.

[0073] [Third Embodiment] In the third embodiment, a case in which a polymer material is subjected to combined degradation due to environmental load and stress load will be described.

[0074] The configuration of the durability evaluation system is the same as in the first and second embodiments.

[0075] For example, the test apparatus 10 performs a process of subjecting the polymer material to photo-oxidative degradation and a process of repeatedly bending it. For example, photo-oxidative degradation is applied for 100 hours, and each polymer material is bent five times at 0 degrees, 30 degrees, 50 degrees, 90 degrees, and 120 degrees.

[0076] The above two processes are repeated, and when the time of photo-oxidative degradation exceeds, for example, 1000 hours, the measuring device 20 measures the amount of chemiluminescence emitted, and the evaluation device 30 evaluates the durability of the polymer material based on the magnitude of the amount of chemiluminescence emitted or the magnitude of the cumulative amount of emitted light.

[0077] For example, the evaluation device 30 determines the cumulative chemiluminescence emission amount for multiple polymer materials that have been degraded by photo-oxidation and bending under the same conditions using the chemiluminescence method, and evaluates polymer materials with lower cumulative chemiluminescence emission amounts as having higher degradation resistance.

[0078] Figure 9 shows an example of operation of the durability evaluation system according to the third embodiment.

[0079] The test apparatus 10 irradiates each polymer material test specimen with ultraviolet light emitted from a xenon lamp for 100 hours (step S301).

[0080] Next, the test apparatus 10 bends each test specimen five times at a 50-degree angle (step S302).

[0081] Next, it is determined whether the test time has exceeded 1000 hours (step S303). If the test time has not exceeded 1000 hours, the process returns to step S301.

[0082] When the test time exceeds 1000 hours, proceed from step S304 onwards. Steps S304 to S308 shown in Figure 9 are the same as steps S103 to S107 shown in Figure 4.

[0083] Figure 10 shows the evaluation results of the degradation resistance performance of samples I to IV of the four test specimens. Sample I was judged to have insufficient degradation resistance because its cumulative chemiluminescence emission was greater than 600,000 counts. Samples II to IV were judged to have sufficient degradation resistance because their cumulative chemiluminescence emission was 600,000 counts or less.

[0084] According to the third embodiment, the test apparatus 10 degrades the polymer material by applying environmental and stress loads, the measuring device 20 measures the amount of chemiluminescence emitted from the degraded polymer material, and the evaluation device 30 calculates the durability of the polymer material based on the magnitude of the cumulative amount of chemiluminescence emitted within a predetermined time. This makes it possible to capture the initial stages of degradation of the polymer material and shorten the total test time for evaluating the durability of the polymer material.

[0085] Furthermore, according to the third embodiment, since the amount of chemiluminescence light emitted is measured, the degree of oxidation, durability, and degradation of the polymer material can be quantitatively evaluated.

[0086] [Fourth Embodiment] The first to third embodiments described cases where different types of loads were applied to the polymer material. The fourth embodiment describes a case where the evaluation index for degradation resistance is weighted. Specifically, the magnitude of the mechanical property value (degree of physical change due to stress) measured on the polymer material is also added to the evaluation index.

[0087] Figure 11 shows an example of the configuration of a durability evaluation system according to the fourth embodiment. The durability evaluation system 1 includes a second test apparatus 40 in addition to the configuration of the first to third embodiments.

[0088] The second test apparatus 40 is a device that applies mechanical stress to a polymer material and measures the resulting mechanical property values ​​of the polymer material. For example, the second test apparatus 40 is a device that can perform tests in accordance with ISO 527, JIS K7161, etc.

[0089] Specifically, the second testing apparatus 40 performs uniaxial monotonic tensile tests, bending tests, compression tests, Charpy impact tests, Vickers hardness tests, and viscoelasticity tests on polymer materials subjected to environmental loads and stress loads.

[0090] The evaluation device 30 also uses the magnitude of the mechanical property values ​​of the polymer material measured by the second test device 40 to evaluate the degradation resistance of the polymer material. For example, the evaluation device 30 evaluates that the degradation resistance is high if the elongation at break measured in a uniaxial monotonic tensile test is greater than a certain value compared to before composite degradation.

[0091] In the fourth embodiment, the third polymer material 100c shown in Figure 2(c) is used. The third polymer material 100c is a test specimen cut into a dumbbell shape (JIS K7161-2 5A) from an injection-molded product made of an olefin-based polymer material, including a living hinge structure. The specimen is cut in a direction in which the linear living hinge structure is perpendicular to the tensile direction of the test specimen (y-direction in Figure 2).

[0092] Figure 12 shows an example of operation of the durability evaluation system according to the fourth embodiment.

[0093] Two test specimens are prepared. These two specimens are made of the same material and are of similar size and shape. One specimen will be used for evaluation. The other specimen will be used to pre-measure the elongation at break before degradation.

[0094] The test apparatus 10 irradiates a test specimen of the third polymer material 100c with ultraviolet light emitted from a xenon lamp for 100 hours (step S401).

[0095] Next, the test apparatus 10 bends the test specimen five times at a 50-degree angle (step S402).

[0096] Next, it is determined whether the test time has exceeded 1000 hours (step S403). If the test time has not exceeded 1000 hours, the process returns to step S401.

[0097] If the test time exceeds 1000 hours, the measuring device 20 places the test specimen in a chamber (JIS K7351) set to a nitrogen gas atmosphere and a constant temperature of 160°C, and measures the amount of chemiluminescence emitted from the surface of the test specimen for 10 minutes (step S404).

[0098] Next, the evaluation device 30 calculates the cumulative luminescence amount of the chemiluminescence measured over 10 minutes (step S405).

[0099] Next, the evaluation device 30 determines whether the cumulative chemiluminescence emission amount is 600,000 counts or less (step S406).

[0100] If the cumulative chemiluminescence emission is 600,000 counts or less, the second test apparatus 40 performs a tensile test on the test specimen at a tensile speed of 20 mm / min (step S407).

[0101] If the cumulative chemiluminescence emission is greater than 600,000 counts, the evaluation device 30 determines that the degradation resistance is insufficient (step S408).

[0102] After step S407, the evaluation device 30 calculates the remaining elongation at fracture of the deteriorated specimen relative to the specimen before deterioration (= elongation at fracture after deterioration × 100 / elongation at fracture before deterioration), and determines whether the remaining elongation at fracture exceeds 75% (step S409).

[0103] Finally, the evaluation device 30 determines that the degradation resistance of the test specimen is sufficient if the remaining elongation at break exceeds 75% (step S410), and determines that the degradation resistance of the test specimen is insufficient if the remaining elongation at break is 75% or less (step S411).

[0104] Figure 13 shows the evaluation results of the degradation resistance performance of samples I to IV of the four test specimens. Sample I was not measured because the cumulative chemiluminescence emission was greater than 600,000 counts. Sample II had a cumulative luminescence of 600,000 counts or less, but the elongation at break was 75% or less, so its degradation resistance was judged to be generally sufficient. Samples III and IV had a cumulative luminescence of 600,000 counts or less, and the elongation at break was greater than 75%, so their degradation resistance was judged to be sufficient.

[0105] According to the fourth embodiment, the test apparatus 10 applies environmental load and stress load to the polymer material, the measuring device 20 measures the amount of chemiluminescence emitted from the deteriorated polymer material, the second test apparatus 40 applies mechanical stress to the polymer material, and the evaluation device 30 calculates the durability of the polymer material based on the magnitude of the cumulative amount of chemiluminescence emitted within a predetermined time and the mechanical property values. This makes it possible to capture the initial stage of deterioration of the polymer material and shorten the total test time for evaluating the durability of the polymer material.

[0106] Furthermore, according to the fourth embodiment, since the amount of chemiluminescence light emitted is measured, the degree of oxidation, durability, and degradation of the polymer material can be quantitatively evaluated.

[0107] [Modifications of Evaluation Indicators for Degradation Resistance] (Modification 1) As explained above, the evaluation indicators for degradation resistance can be the amount of chemiluminescence emitted and the mechanical property values. In the fourth embodiment, the case in which these two types of evaluation indicators are used in that order was described, but they may also be used in combination at the same time.

[0108] For example, the evaluation device 30 can measure the amount of light emitted by chemiluminescence under the same conditions for multiple polymer materials that have been degraded by photo-oxidation or bending under the same conditions, and also measure their mechanical properties. If the amount of light emitted by chemiluminescence is x and the mechanical property value (e.g., tensile strength) is y, then materials with a small x and a large y may be evaluated as having higher degradation resistance.

[0109] For example, the evaluation device 30 may use an evaluation index value calculated by the formula by-ax (where a is a coefficient that adjusts the contribution rate of x, and b is a coefficient that adjusts the contribution rate of y) to evaluate that a higher by-ax value indicates higher degradation resistance. Note that the formula for calculating the evaluation index value from the luminescence and mechanical properties is not limited to by-ax, and may be another formula that can calculate a more appropriate index according to the actual degree of degradation.

[0110] For example, the evaluation device 30 may evaluate multiple polymer materials that have been degraded by photo-oxidation or bending under the same conditions, and determine that the degradation resistance is higher when x is the amount of chemiluminescence emitted, y is the mechanical property after degradation, and yi is the mechanical property value before degradation.

[0111] For example, the evaluation device 30 may use an evaluation index value calculated by the formula b(y / yi)-ax, and evaluate that a higher value of b(y / yi)-ax indicates higher degradation resistance. Note that the formula for calculating the evaluation index value from the luminescence and mechanical properties is not limited to b(y / yi)-ax, and another formula that can calculate a more appropriate index according to the actual degree of degradation may be used.

[0112] (Modification 2) Environmental load and stress load may be used as evaluation indicators for degradation resistance.

[0113] For example, the evaluation device 30 may evaluate multiple polymer materials that have been degraded to the same level of chemiluminescence emission, and determine that polymer materials with higher light irradiation doses, more bending cycles, and higher mechanical properties after degradation have higher degradation resistance.

[0114] For example, the evaluation device 30 may evaluate multiple polymer materials that have been degraded to the same level of chemiluminescence emission, and determine that polymer materials with higher light irradiation doses and bending cycles, and with less deterioration in mechanical properties before and after degradation, have higher degradation resistance.

[0115] In other words, the evaluation device 30 may calculate and compare an index of the degree of degradation based on the amount of light irradiation, the number of bending cycles, and the mechanical properties before or after degradation.

[0116] For example, the evaluation device 30 may evaluate that polymer materials that have been degraded to a similar degree in mechanical properties have higher degradation resistance if they have been exposed to more light, folded more times, and emitted more chemiluminescence.

[0117] In other words, the evaluation device 30 may calculate and compare an index of the degree of degradation from the amount of light irradiation, the number of bending cycles, and the amount of chemiluminescence emitted.

[0118] [Other] This disclosure is not limited to the embodiments described above. This disclosure can be modified in numerous ways within the scope of its essence. For example, two or more embodiments from the first to fourth embodiments may be arbitrarily combined. Furthermore, it is preferable to set appropriate values ​​for the numerical values ​​used in each embodiment according to the installation environment, expected lifespan, and usage method of the polymer material.

[0119] The evaluation device 30 of this embodiment described above can be realized using a general-purpose computer system, for example, as shown in Figure 14, which includes a CPU 901, a memory 902, a storage 903, a communication device 904, an input device 905, and an output device 906. The memory 902 and the storage 903 are storage devices. In this computer system, the CPU 901 executes a predetermined program loaded onto the memory 902, thereby realizing each function of the evaluation device 30.

[0120] The evaluation device 30 may be implemented on a single computer. The evaluation device 30 may be implemented on multiple computers. The evaluation device 30 may also be a virtual machine implemented on a computer.

[0121] The program for the evaluation device 30 can be stored on a computer-readable recording medium such as an HDD, SSD, USB memory, CD, or DVD. A computer-readable recording medium is, for example, a non-transitory recording medium. The program for the evaluation device 30 can also be distributed via a communication network.

[0122] 1 Durability evaluation system 10 Test device 20 Measurement device 30 Evaluation device 31 Processing unit 32 Output unit 33 Storage unit 40 Second test device 100 Polymer material 100a First polymer material 100b Second polymer material 100c Third polymer material 901 CPU 902 Memory 903 Storage 904 Communication device 905 Input device 906 Output device

Claims

1. An evaluation method comprising: a first step in which a test device applies a load to a polymer material; a second step in which a measuring device measures the amount of chemiluminescence emitted from the polymer material; and a third step in which an evaluation device calculates the durability of the polymer material based on the magnitude of the amount of chemiluminescence.

2. The evaluation method according to claim 1, wherein in the second step, the amount of chemiluminescence emitted from the polymer material placed in an inert atmosphere and at a surface reaction temperature is measured, and in the third step, the durability of the polymer material is calculated based on the magnitude of the total amount of chemiluminescence within a predetermined time.

3. The evaluation method according to claim 1, wherein in the third step, the durability of the polymer material is calculated based on the magnitude of the chemiluminescence and the degree of physical change due to stress on the polymer material.

4. The evaluation method according to claim 1, wherein the load is one or more of light, heat, water, and stress.

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