JP2014139514A - Method for measuring deterioration degree of insulating material and apparatus for measuring deterioration degree of insulating material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily measure a deterioration degree of insulating materials of various types and shapes.SOLUTION: An insulating material before deterioration and the insulating material after deterioration are each dissolved in a solvent; and intrinsic viscosities are calculated based on the concentrations and viscosities of the respective solutions. An intrinsic viscosity is calculated based on the Solomon-Ciuta equation. A deterioration degree of an insulating material after deterioration is determined based on the intrinsic viscosity of a solution in which the insulating material before deterioration is dissolved and on the intrinsic viscosity of a solution in which the insulating material after deterioration is dissolved. Otherwise, a ratio of the intrinsic viscosity of the solution in which the insulating material after deterioration is dissolved to the intrinsic viscosity of the solution in which the insulating material before deterioration is dissolved is calculated as a molecular weight retention rate; and a deterioration degree of the insulating material after deterioration is measured based on the molecular weight retention rate.

Description

  The present invention relates to a deterioration degree measuring method and a deterioration degree measuring apparatus for measuring a deterioration degree of an insulating material.

  The greatest weakness of an insulating material such as a synthetic resin is deterioration, and the deterioration proceeds slightly even in the state of the raw material immediately after production before polymer molding. The deterioration of the insulating material means that the performance, function, appearance and other characteristics of the insulating material are deteriorated due to the main chain or side chain of the molecule constituting the insulating material being cut or cross-linked. .

  The deterioration of the insulating material is promoted by various factors such as stress, temperature, oxygen, moisture, ultraviolet rays, radiation, ozone, and chemicals. For example, thermal degradation of the insulating material proceeds in the presence of oxygen. In addition, an insulating material having an ester bond in a molecular skeleton such as polycarbonate (PC), polyethylene terephthalate (PET), or polybutylene terephthalate (PBT) is hydrolyzed in the presence of moisture.

  It is still difficult to evaluate the deterioration of insulating materials due to various types of insulating materials, different usage conditions, and various criteria for determining the service life. There is no provision.

  Since the usage situation of insulating materials is increasing in the world, if deterioration evaluation cannot be performed for each material, there is a possibility of causing troubles and accidents depending on usage conditions and usage conditions. If it can be predicted how much the environment and load will cause the insulation material to deteriorate, it will be possible to cope with the occurrence of an accident and the time for replacement in advance. However, since the usage environment of products using insulating materials is unknown, material manufacturers have little data on deterioration of insulating materials.

  As described above, in order to increase the reliability of a product using an insulating material, a technique for diagnosing the deterioration of the insulating material is necessary, but there is no technique that can easily evaluate the deterioration of the insulating material.

  As a method for diagnosing the degree of deterioration of the insulating material, there is a method of diagnosing the degree of deterioration of the insulating material by comparing the tensile strength of the insulating material in the initial state and the insulating material after deterioration for a predetermined time (for example, Patent Document 1).

  As another diagnostic method for diagnosing the degree of deterioration of the insulating material, there is a method of determining the life of the insulating material based on the elongation of the insulating material (for example, Patent Document 2). In Patent Document 2, the cable (insulating material) is deteriorated to a value that gives a life (for example, a state where the elongation is 50% of the initial state), and Arrhenius is a relational expression between the acceleration temperature and the test period at the elongation value. A plot is created, and the cable life is determined based on this Arrhenius plot. In the environmental test performed by this diagnostic method, an accelerated test corresponding to the actual environmental conditions of the actual machine is performed. The acceleration condition of this acceleration test is set based on the activation energy of the cable and the operation period. To calculate this activation energy, it is necessary to thermally degrade the cable under at least three conditions with different acceleration temperatures.

  As described above, as a method for diagnosing the degree of deterioration of an insulating material, an insulating material is accelerated and deteriorated under various constant temperature and humidity conditions, and a temporal change such as tensile strength or breaking elongation of the insulating material is measured. (For example, the time (half-life) during which the tensile strength or elongation at break is reduced to 50% of the initial value) is defined as the life of the insulating material. In addition, the Arrhenius plot that plots the measurement results of these accelerated deteriorations against the reciprocal of the temperature, the tensile strength of the insulating material that has deteriorated in the actual natural environment, etc. are measured and compared with the results of the Arrhenius plots. Thus, the degree of deterioration of the deteriorated insulating material is determined.

  Other diagnostic methods for diagnosing the degree of deterioration of the insulating material include a diagnostic method that uses the measured value of the insulation resistance on the surface of the insulating material as an indicator of the degree of deterioration, and when the insulating material changes color according to the degree of deterioration. There is also a diagnostic method using the degree of discoloration of the insulating material as an indicator of the degree of deterioration.

JP-A-6-308000 JP 2001-255262 A

  However, for mechanical measurements such as tensile strength and elongation at break, a relatively large specimen must be collected. In other words, the insulating material that is actually used needs to have a size and shape that allow a test piece to be collected, and may be difficult to apply widely.

  In addition, deterioration of an insulating material whose deterioration is accelerated due to light such as ultraviolet rays is particularly accelerated in terms of deterioration of the surface exposed to ultraviolet rays, unlike thermal deterioration or degradation due to hydrolysis. As a result, the degree of deterioration may vary in the depth direction from the surface of the insulating material exposed to ultraviolet rays. In this case, the degree of deterioration cannot be correctly evaluated even if a test piece is taken and measured for mechanical strength. There is a fear.

  In view of the above circumstances, an object of the present invention is to provide a technique that contributes to widening the range of an insulating material to be measured in a measuring method or measuring device for the degree of deterioration of an insulating material.

  A method for measuring the degree of deterioration of an insulating material of the present invention that achieves the above object is a method for measuring the degree of deterioration of an insulating material, wherein the insulating material in an initial state is dissolved in a solvent, the viscosity of this solution is measured, Dissolving the insulating material after time degradation in a solvent, measuring the viscosity of this solution, based on the viscosity of the solution in which the insulating material in the initial state is dissolved, and the viscosity of the solution in which the insulating material after deterioration is dissolved, The degree of deterioration of the insulating material after the deterioration is determined.

  In addition, the degradation measuring apparatus for insulating material according to the present invention that achieves the above object comprises means for preserving the intrinsic viscosity of a solution in which the insulating material in the initial state is dissolved, and a solution for dissolving the insulating material after deterioration for a predetermined time. Based on the means for measuring the viscosity, the intrinsic viscosity of the solution in which the insulating material in the initial state is dissolved, and the intrinsic viscosity calculated based on the viscosity of the solution in which the insulating material after degradation is dissolved, after the deterioration And a means for determining the degree of deterioration of the insulating material.

  According to the above invention, in the deterioration degree measuring method or deterioration degree measuring apparatus for an insulating material that measures the degree of deterioration of the insulating material, it is possible to contribute to expanding the range of the insulating material that is a measurement target.

It is a schematic diagram of the test piece which extract | collects a sample. It is a flow figure (when hexafluoroisopropanol is used for a solvent) explaining the degradation degree measuring method of the insulating material performed in Example 1 of the present invention. It is a flowchart (when toluene is used for a solvent) explaining the degradation degree measuring method of the insulating material performed in Example 1 of this invention. It is explanatory drawing explaining the measurement principle of a falling body type automatic microviscometer. It is a figure which shows the measurement result of Example 1, and is a characteristic view which shows the change of the molecular weight retention with respect to the deterioration time of PC + PBT. It is a figure which shows the measurement result of Example 1, and is a characteristic view which shows the change of the tensile strength, elongation, and molecular weight retention with respect to the deterioration time of PC + PBT. It is a figure which shows the measurement result of Example 1, and is a characteristic figure which shows the change of the molecular weight retention with respect to the degradation time of each layer of PC + PBT collected in layers. It is a figure which shows the measurement result of Example 1, (a) The characteristic view which shows the change of the molecular weight retention with respect to the degradation time of each PC layer extract | collected in layer form, (b) Tensile strength, elongation, and molecular weight retention with respect to the degradation time of PC It is a characteristic view which shows the change of a rate. It is a figure which shows the measurement result of Example 1, (a) The characteristic view which shows the change of the molecular weight retention rate with respect to the degradation time of each layer of bioPC extract | collected in layer form, (b) Tensile strength with respect to the degradation time of bioPC, elongation, and It is a characteristic view which shows the change of molecular weight retention. It is a figure which shows the measurement result of Example 1, (a) The characteristic view which shows the change of the molecular weight retention with respect to the degradation time of each layer of PPE extract | collected in layer form, (b) Tensile strength, elongation, and molecular weight retention with respect to the degradation time of PPE It is a characteristic view which shows the change of a rate. It is a figure which shows the measurement result of Example 2, and is a characteristic view which shows the change of the molecular weight retention with respect to the deterioration time of PC + PBT. It is a figure which shows the measurement result of Example 2, and is a characteristic view which shows the change of the tensile strength with respect to the deterioration time of PC + PBT, elongation, and molecular weight retention. It is a figure which shows the measurement result of Example 2, and is a characteristic view which shows the change of the molecular weight retention rate with respect to the deterioration time of each layer of PC + PBT collected in layers. It is a figure which shows the measurement result of Example 2, (a) The characteristic view which shows the change of the molecular weight retention with respect to the degradation time of each PC layer extract | collected in layer form, (b) Tensile strength, elongation, and molecular weight retention with respect to the degradation time of PC It is a characteristic view which shows the change of a rate. It is a figure which shows the measurement result of Example 2, (a) The characteristic view which shows the change of the molecular weight retention rate with respect to the deterioration time of each layer of bioPC extract | collected in layer form, (b) Tensile strength with respect to the deterioration time of bioPC, elongation, and It is a characteristic view which shows the change of molecular weight retention. It is a figure which shows the measurement result of Example 2, (a) The characteristic view which shows the change of the molecular weight retention with respect to the deterioration time of each layer of PC + PET extract | collected in layer form, (b) Tensile strength, elongation, and molecular weight maintenance with respect to deterioration time of PC + PET It is a characteristic view which shows the change of a rate. It is a figure which shows the measurement result of Example 2, (a) The characteristic view which shows the change of the molecular weight retention with respect to the deterioration time of each layer of PPE extract | collected in layer form, (b) Tensile strength, elongation, and molecular weight maintenance with respect to the deterioration time of PPE It is a characteristic view which shows the change of a rate. It is a figure which shows the measurement result of Example 3, and is a figure which shows the measurement result of the molecular weight retention of PE film in which deterioration conditions differ, and the tensile strength of PE film. It is the schematic of the degradation degree measuring apparatus of the insulating material which concerns on embodiment of this invention.

  The insulating material deterioration degree measuring method and deterioration degree measuring apparatus of the present invention will be described in detail with reference to the drawings.

  The deterioration degree measuring method and the deterioration degree measuring apparatus according to the embodiment of the present invention dissolve an insulating material before deterioration (insulating material in an initial state) and an insulating material after deterioration in a solvent, respectively, and dissolve the insulating material before deterioration. The intrinsic viscosity of the solution and the intrinsic viscosity of the solution in which the deteriorated insulating material is dissolved are calculated, and the degree of deterioration of the insulating material is measured based on the calculated intrinsic viscosity. Here, the insulating material before deterioration refers to an insulating material that serves as a reference for judging the progress of the degree of deterioration of the insulating material after deterioration.

  In the measurement of the degree of deterioration of the insulating material, the ratio of the intrinsic viscosity of the solution in which the insulating material after deterioration to the intrinsic viscosity of the solution in which the insulating material before deterioration is dissolved is defined as the molecular weight retention rate. It is characterized by being an index of the degree of material degradation.

  As the solvent for dissolving the insulating material, a solvent capable of dissolving the insulating material may be appropriately selected and used. For example, formic acid, sulfuric acid, m-cresol, phenol, tetrachloroethane, cyclohexane, tetrahydrofuran (THF), decahydronaphthalene, di Solvents such as chlorobenzene, trichlorobenzene, dichloromethane, methylene chloride, trichloromethane, chlorophenol, toluene, hexafluoroisopropanol are used alone or in combination. As the mixed solvent, for example, a mixed solvent of phenol and tetrachloroethane, a mixed solvent of phenol and dichlorobenzene, or the like is used.

  Here, the intrinsic viscosity [η] (also called intrinsic viscosity) of the insulating material will be described. The intrinsic viscosity [η] is an amount that can be related to the particle size and molecular weight of a solute (insulating material) dispersed in a solution.

The intrinsic viscosity [η] is a value of (specific viscosity η _sp ) / (solution concentration c) in an infinitely diluted solution. Therefore, η _sp / c can be plotted against c and can be obtained as a value obtained by extrapolating c to 0 (extrapolated value). The specific viscosity η _sp corresponds to the increase in the viscosity of the solution due to the dissolution of the solute in the solvent, and the relative viscosity η _rel is the ratio of the viscosity η of the solution in which the insulating material is dissolved in the solvent and the viscosity η _{0 of the} solvent. This is a value obtained by subtracting 1 from (= η / η ₀ ). That is, the specific viscosity η _sp is represented by the formula (1).
η _sp = η _rel −1 = η / η ₀ −1 = (η−η ₀ ) / η ₀ (1)
Various formulas for obtaining the intrinsic viscosity based on the concentration and viscosity of the solution have been proposed. For example, there is the Solomon-Ciuta equation shown in Equation (2), and the intrinsic viscosity [η] is expressed as a function of the solution concentration c, specific viscosity η _sp and relative viscosity η _rel . Thus, a simple method has been proposed in which the viscosity is measured at the concentration of one solution and the intrinsic viscosity is calculated based on the concentration and viscosity of the solution.

In addition, the relationship between the intrinsic viscosity [η] of the insulating material and the molecular weight M of the insulating material is the Mark-Houwink-Sakurada relational expression shown in Expression (3). In Equation (3), K and a are constants determined by the type of insulating material and the type of solvent. Therefore, the molecular weight (viscosity average molecular weight) of the insulating material can be obtained based on the intrinsic viscosity [η].
[Η] = KM ^a (3)
Thus, there is a certain relationship between the intrinsic viscosity [η] and the molecular weight M of the insulating material, and the intrinsic viscosity of the solution in which the insulating material after degradation is dissolved relative to the intrinsic viscosity of the solution in which the insulating material before degradation is dissolved. Obtaining the ratio is nothing but obtaining the ratio between the molecular weight of the insulating material before deterioration and the molecular weight of the insulating material after deterioration.

  That is, the measurement result of the intrinsic viscosity of the solution in which the insulating material before deterioration is taken as the molecular weight retention rate of 100%, and the intrinsic viscosity of the solution in which the insulating material after deterioration is dissolved relative to the intrinsic viscosity of the solution in which the insulating material before deterioration is dissolved. This molecular weight retention rate can be used as an index of the degree of deterioration of the insulating material.

  As a result, K and a that are constants specific to the insulating material and the solvent in the Mark-Houwink-Sakurada relational expression may not be obtained in advance through complicated measurement and calculation work for each insulating material. The degree of deterioration of the insulating material can be measured simply by determining the ratio between the intrinsic viscosity of the solution in which the insulating material before deterioration is dissolved and the intrinsic viscosity of the solution in which the insulating material after deterioration is dissolved.

  Hereinafter, a specific example will be given to describe in detail a deterioration level measuring method and a deterioration level measuring apparatus for an insulating material according to an embodiment of the present invention.

[Example 1]
In the method for measuring the degree of deterioration of an insulating material according to Example 1, a test piece formed of a mixed resin of polycarbonate and polybutylene terephthalate (hereinafter referred to as PC + PBT) is accelerated and deteriorated by a constant temperature and humidity method. The degree of deterioration was measured. The degree of deterioration was measured based on the measurement of the viscosity of the solution in which the test piece was dissolved.

  For the viscosity measurement, a viscosity measuring machine (model number: automatic micro viscometer AMVn) made by Anton Paar Japan was used, and for the accelerated deterioration test, a constant temperature and humidity test machine made by ISUZU (model number: μ SERIES quartz) was used. In addition, a tensile tester (model number: Instron 33R4206) manufactured by Instron Japan was used for the tensile test and the elongation test.

  In addition to PC + PBT, the test piece was polycarbonate (hereinafter referred to as PC), plant-derived PC (hereinafter referred to as bio PC), a mixed resin of polycarbonate and polyethylene terephthalate (hereinafter referred to as PC + PET), polyphenylene ether (hereinafter referred to as PC + PBT). The test piece was also tested in the same manner.

  As shown in FIG. 1, the shape of the test piece is a dumbbell shape (as defined in JIS standard, considering that a tensile test and an elongation test are performed as a comparison test for the deterioration diagnosis method according to Example 1 of the present invention). JIS K1113 type 1).

  First, the test piece was accelerated and deteriorated in a constant temperature and humidity apparatus having a temperature of 85 ° C. and a relative humidity of 85%. The deterioration time was 0, 144, 270, 504, 1008, 2000 hours, and a test piece before accelerated deterioration was used as the 0-hour sample.

  With reference to FIGS. 2 and 3, the deterioration degree measuring method according to the first embodiment will be described. FIG. 2 is a flowchart of a method for measuring the degree of deterioration when hexafluoroisopropanol is used as a solvent. FIG. 3 is a flow chart of the degradation degree measuring method when toluene is used as the solvent. Since the deterioration degree measuring method shown in FIG. 2 and the deterioration degree measuring method shown in FIG. 3 perform the same steps except for the sample dissolution step, the same steps are denoted by the same reference numerals.

  As shown in FIGS. 2 and 3, the deterioration degree measuring method includes a sample collection step S1, a sample dissolution step S2 (sample dissolution step S5), a viscosity measurement step S3, and a deterioration degree determination step S4.

First, the sample collection step S1 will be described. In the sample collection step S1, a sample for viscosity measurement was collected from the test piece by performing the following procedure 1 to procedure 4.
Procedure 1: The thickness of each test piece was measured at three locations with a micrometer, and the thickness of the test piece was recorded.
Procedure 2: About 0.01 g of the test piece was scraped off with a mini planer (with diamond on the cutting edge) or an engraved sword and the like was shaved to some extent from the surface.
Procedure 3: The test piece was shaved with a file while measuring with a micrometer so that the depth was 0.3 mm (from 0.25 mm to less than 0.35 mm) from the initial thickness. At this time, a file was applied so that the scraped surface was as flat as possible. In addition, although the depth which grinds a test piece was 0.3 mm, this is for the purpose of shaving off a predetermined sample amount (about 0.01 g), and is not limited to 0.3 mm. However, if the depth is too shallow, it is difficult to scrape with high accuracy, and if the depth is too deep, a sample is taken more than necessary. Further, since the amount to be collected depends on the area to be scraped, it is preferable to scrape in a depth range of 0.2 to 0.5 mm.
Procedure 4: Procedure 1 to procedure 3 were repeated, and samples of the second and third layers of the test piece were collected.

  Next, the sample dissolution step S2 (sample dissolution step S5) will be described. In dissolving the sample collected from the test piece in the solvent, the insulating material, which is the material constituting the test piece, was dissolved in various solvents, and the most insulating material was dissolved in hexafluoroisopropanol. . This solvent was able to dissolve insulating materials other than PPE among the insulating materials used at room temperature. If the solvent in which the test piece is dissolved can be unified with the same solvent, it is convenient for comparison of measured values and blank measurement of a viscosity measuring apparatus, so hexafluoroisopropanol was used in the examples. And PPE which did not melt | dissolve in hexafluoroisopropanol was dissolved in toluene. PPE does not dissolve unless heated slightly in toluene, so after adding PPE to toluene, it was stirred by ultrasonic vibration for 20 minutes and left in an aluminum bath set at 35 ° C. for 15 minutes to obtain the viscosity of the solution. It was stored in an aluminum bath until immediately before measuring.

  In the sample melting step S2 (sample melting step S5), if the insulating material is excessively deteriorated, a part of the sample may not be dissolved. In that case, the intrinsic viscosity of the supernatant of the solution is measured, and the sample that has not dissolved but precipitated is filtered and dried, and then its weight is weighed, and the weighed weight is subtracted from the weight of the collected sample. Concentration calculation was performed.

  As shown in FIG. 2, in the sample dissolution step S2, the collected sample (PC + PBT, 0.01 g) was transferred to a 5 mL volumetric flask and diluted with hexafluoroisopropanol to prepare a 0.2 wt% solution. Then, it was allowed to stand at room temperature for 24 hours, and the collected sample was completely dissolved. On the other hand, as shown in FIG. 3, in the sample dissolution step S5, PPE (0.01 g) was transferred to a 5 mL volumetric flask and then diluted with toluene and stirred by ultrasonic vibration for 20 minutes. And it left still for 15 minutes in the aluminum bath set to 35 degreeC, and stored in the aluminum bath until just before measuring the viscosity of a solution.

  In the viscosity measurement step S3, the viscosity of the solution in which the sample was dissolved (hereinafter referred to as the solution) was measured using a falling body type automatic micro viscometer. First, about 0.4 mL of the solution was collected in a φ1.6 mm capillary 2 of a falling body type automatic micro viscometer shown in FIG. The set temperature was set to 30 ° C. when hexafluoroisopropanol was the solvent and 40 ° C. when toluene was the solvent.

  Since the difference in measurement temperature affects the viscosity, it was kept constant. The measurement temperature was set to a temperature at which the influence of solvent volatilization does not affect the viscosity measurement result. The lower the set temperature, the more the influence of solvent volatilization can be reduced. In addition, the higher the set temperature, the smaller the viscosity, and the faster the ball 3 rolls, the shorter the measurement time. Therefore, measurement can be performed at room temperature depending on how the measurement sample is dissolved.

  The inclination angle of the capillary 2 was set to 30, 35, 40, 45, 50, 55, 60, 65, and 70 °, and the falling time of the ball 3 was measured at the inclination angle of each capillary 2. In the falling body type automatic micro viscometer, the drop time of the ball 3 is measured at at least four angles of the capillary 2, and the viscosity is calculated based on this measurement. Therefore, the inclination angle of the capillary 2 is not limited to the embodiment, and the drop time of the ball 3 is measured for each inclination angle of the capillary 2 set as appropriate, and the viscosity of the solution is calculated based on this drop time. That's fine. For example, the inclination angle of the capillary 2 may be set so that the measurement time by the inclination of one angle is about 10 to 45 seconds. If the inclination angle of the capillary 2 is set to 10 ° to 20 °, it may take too much time to measure the drop time of the ball 3. Further, when the inclination angle of the capillary 2 is about 80 ° to 90 °, the ball 3 is not rolled but may slide and move, and there is a possibility that an accurate viscosity measurement result cannot be obtained. Therefore, the inclination angle of the capillary 2 is preferably set to 30 ° to 70 °.

  In the deterioration degree determination step S4, the measured viscosity of the solution was substituted into the Solomon-Ciuta equation to calculate the intrinsic viscosity [η]. In addition, the ratio of the intrinsic viscosity of the solution in which the sample after degradation was dissolved to the intrinsic viscosity of the solution in which the sample before degradation was dissolved was calculated to calculate the molecular weight retention of the sample after degradation.

  FIG. 5 shows the change in the molecular weight retention rate with respect to the deterioration time of PC + PBT (collected sample of the first layer from the deteriorated surface). As shown in FIG. 5, it was confirmed that the molecular weight retention decreased with the passage of deterioration time.

  FIG. 6 shows the measurement results of the tensile test with respect to the deterioration time of PC + PBT, the measurement results of the elongation test, and the measurement results of the molecular weight retention rate (sample collected from the first layer from the deteriorated surface). The tensile test and the elongation test of the test piece were performed in order to confirm the relationship between the decrease in the molecular weight retention rate of the test piece and the deterioration of the test piece. In FIG. 6, the vertical axes indicating the values of elongation [mm] and tensile strength [MPa] are axes having the same scale and different units (the same applies to the figures showing other measurement results).

  As shown in FIG. 6, it was confirmed that the tensile strength decreased with the passage of deterioration time. As can be seen from FIG. 6, the tensile strength decreased as the molecular weight retention decreased. Further, as a result of the elongation test, there was a point that the elongation increased with the passage of part of the degradation time. However, when the molecular weight retention rate decreased, the elongation of the sample also decreased.

  FIG. 7 shows the results obtained by collecting samples from the test piece in layers in the thickness direction and measuring the degree of deterioration of each sample. As shown in FIG. 7, by collecting samples from the test piece in layers, it was possible to measure how far the deterioration had progressed inside the test piece as the deterioration time passed. In other words, by comparing the molecular weight retention rates of the samples from the first layer to the third layer, even when accelerated deterioration under the same constant temperature and humidity, the layer closer to the surface is slightly more deteriorated, but the deterioration is more advanced. I found out.

  FIG. 8A and FIG. 8B show the results of measuring the PC deterioration degree by the method for measuring the deterioration degree of the insulating material according to Example 1. FIG. As shown to Fig.8 (a), it was confirmed that a molecular weight retention rate falls with progress of deterioration time. In addition, in PC, the big difference was not able to be confirmed by the measurement result of the 1st layer, the 2nd layer, and the 3rd layer. Further, as shown in FIG. 8B, in the initial stage of deterioration, the molecular weight retention rate, the tensile strength, and the elongation are decreased. It decreases according to. This indicates that even when the insulating material is PC, the degree of deterioration of the insulating material can be evaluated based on the change in the molecular weight retention rate.

  FIG. 9A and FIG. 9B show the results of measuring the degree of degradation of bio PC by the method for measuring the degree of degradation of the insulating material according to Example 1. FIG. As shown in FIG. 9 (a), it was confirmed that the molecular weight retention rate slightly decreased as the deterioration time passed. In BioPC, a large difference could not be confirmed in the measurement results of the first, second, and third layers. Further, as shown in FIG. 9B, after 500 hours, the molecular weight retention rate, tensile strength, and elongation are slightly decreased with the passage of deterioration time. This indicates that even when the insulating material is BioPC, the degree of deterioration of the insulating material can be evaluated based on the change in the molecular weight retention rate.

  FIG. 10A and FIG. 10B show the results of measuring the degree of deterioration of PPE by the method for measuring the degree of deterioration of the insulating material according to Example 1. FIG. As shown in FIG. 10A, the PPE hardly deteriorated during the deterioration time of Example 1. Moreover, as shown in FIG.10 (b), the measurement result of tensile strength and elongation also showed that PPE did not deteriorate. That is, it was found that even when the insulating material is PPE, the degree of deterioration of the insulating material can be evaluated based on the change in the molecular weight retention rate.

[Example 2]
In the method for measuring the degree of deterioration of an insulating material according to Example 2, an accelerated deterioration test using ultraviolet rays was performed as a weather resistance test for a test piece formed of an insulating material, and the intrinsic viscosity of a solution in which the deteriorated test piece was dissolved was measured. . As the accelerated weather resistance tester, Super Xenon Weather Meter SX75 (XWOM) manufactured by Suga Test Instruments Co., Ltd. was used. This is because aging deterioration under indoor fluorescent light under controlled humidity temperature is assumed.

  The test piece was accelerated and deteriorated by irradiating the test piece with ultraviolet rays using a xenon arc lamp type accelerated weathering tester. The deterioration time was 0, 100, 200, 500, 1000, 2000 hours, and a test piece before accelerated deterioration was used as the 0-hour sample.

  The test piece tested similarly about the test piece formed by PC, bio PC, PC + PET, and PPE other than PC + PBT.

  The shape of the test piece was a dumbbell shape (JIS K1113 No. 1 type) defined in the JIS standard, as in Example 1.

  The method for collecting the sample for measuring the viscosity from the test piece was the same as in Example 1, and samples were collected in layers from the deteriorated surface at a depth of 0.3 mm. However, since the test piece that was irradiated with ultraviolet rays on the surface of the sample as in Example 2 was deteriorated by irradiating ultraviolet rays on one side of the test piece, the test piece was deteriorated. A sample was taken from.

  The method for measuring the degree of deterioration of the insulating material according to Example 2 evaluates the degree of deterioration of the test piece using the same method as the method for measuring the degree of deterioration of insulating material according to Example 1, except that the method for promoting deterioration of the test piece is different. did. That is, the flowchart of the degradation degree evaluation method of the second embodiment is the same as that shown in FIGS. 2 and 3, and detailed description thereof is omitted. Further, in the same manner as the method for measuring the degree of deterioration of the insulating material according to Example 1, in order to confirm that the test piece deteriorated due to the decrease in the molecular weight retention rate of the test piece, Tests and elongation tests were performed.

  FIG. 11 shows the change in the molecular weight retention rate with respect to the deterioration time of PC + PBT (sampled first layer from the deteriorated surface) that was accelerated and deteriorated by irradiation with ultraviolet rays. As shown in FIG. 11, it was confirmed that the molecular weight retention rate decreased with the passage of deterioration time.

  FIG. 12 shows the measurement results of the tensile test with respect to the degradation time of PC + PBT, the measurement results of the elongation test, and the measurement results of the molecular weight retention rate (sample collected in the first layer from the degraded surface). From the results shown in FIG. 12, when the surface layer of the sample deteriorates, the results of the tensile test and the elongation test also decrease. However, the tensile strength and the elongation are almost the same after the time when the deterioration is caused to some extent as well as the decrease in the molecular weight retention. As a result, the degree of deterioration did not decrease. This is presumably because the deterioration of the insulating material due to ultraviolet light does not progress so much in a deep layer from the surface of the test piece.

  FIG. 13 shows the results obtained by collecting samples from the test piece in layers in the thickness direction and measuring the degree of deterioration of each sample. As shown in FIG. 13, in the case of accelerated deterioration due to ultraviolet rays, the surface directly irradiated with ultraviolet rays (sample collected in the first layer from the deteriorated surface) decreases in molecular weight retention with deterioration time, and a certain amount of time has elapsed. Then, the degree of deterioration seems to be saturated. On the other hand, it was confirmed that the collected samples of the second layer and the third layer deeper than 0.3 mm hardly decreased in molecular weight retention. From these facts, it can be presumed that in the accelerated deterioration by ultraviolet rays, the molecular weight retention rate of the very surface layer decreases with the deterioration time, but at a certain depth from the surface, the deterioration by ultraviolet rays is not promoted much. As is clear from the results of FIG. 13, by collecting samples in layers and measuring the intrinsic viscosity of each sample, it is possible to estimate where the deterioration has progressed from the surface of the deteriorated sample. . That is, the progress of deterioration from the surface of the insulating material can also be confirmed by collecting the viscosity measurement sample in layers from the surface of the insulating material.

  It has been confirmed that the surface color of the insulating material is changed by accelerated deterioration by ultraviolet rays. Therefore, by determining the relationship between the color of the deteriorated surface of the sample before and after deterioration and the molecular weight retention ratio of that color in advance, a threshold is set for the change in the color of the insulating material. It is also possible to estimate the deterioration progress rate inside the sample of the insulating material from the degree of progress of the deterioration of the insulating material and the deterioration surface.

  FIG. 14A and FIG. 14B show the results of measuring the PC deterioration degree by the method for measuring the deterioration degree of the insulating material according to the second embodiment. As shown in FIG. 14A, it was possible to grasp the degree of deterioration in the depth direction of the insulating material even when the insulating material was PC. Further, as shown in FIG. 14B, the measured values of the molecular weight retention rate and the elongation with the passage of the deterioration time have a correlation, but the tensile strength hardly changes with the passage of the deterioration time. . This is presumably because the degree of deterioration of the surface of the insulating material has little influence on the tensile strength of the insulating material.

  FIG. 15A and FIG. 15B show the results of measuring the degree of bio PC degradation by the method for measuring the degree of degradation of the insulating material according to Example 2. FIG. As shown in FIG. 15 (a), when the insulating material is bio-PC, the deterioration of the first layer progresses as the deterioration time elapses, but the deterioration degree of the second layer and the third layer progresses relatively slowly. I understand. Further, as shown in FIG. 15B, the molecular weight retention rate, the tensile strength, and the elongation decrease as the deterioration time elapses. This indicates that even when the insulating material is BioPC, the degree of deterioration of the insulating material can be evaluated based on the change in the molecular weight retention rate.

  FIG. 16A and FIG. 16B show the results of measuring the degree of PC + PET degradation using the method for measuring the degree of degradation of an insulating material according to Example 2. FIG. As shown in FIG. 16A, the degree of deterioration in the depth direction of the insulating material could be grasped even when the insulating material was PC + PET. Further, as shown in FIG. 16B, the molecular weight retention rate, the tensile strength, and the elongation decrease as the deterioration time elapses. In particular, there was a correlation between the molecular weight retention rate as the deterioration time passed and the degree of decrease in the tensile test. This indicates that even when the insulating material is PC + PET, the degree of deterioration of the insulating material can be evaluated based on the change in the molecular weight retention rate.

  FIG. 17A and FIG. 17B show the results of measuring the degree of deterioration of PPE by the method for measuring the degree of deterioration of the insulating material according to Example 2. FIG. As shown in FIG. 17A, when the insulating material is PPE, the deterioration of the first layer progresses as the deterioration time elapses, but the deterioration degree of the second layer and the third layer progresses relatively slowly. Recognize. Further, as shown in FIG. 17B, although the molecular weight retention rate of the first layer decreases as the deterioration time elapses, the tensile strength and elongation hardly decrease. This indicates that when the insulating material is PPE, the surface deterioration of the insulating material has little influence on the measured values of tensile strength and elongation.

[Example 3]
In the method for measuring the degree of deterioration of an insulating material according to Example 3, the degree of deterioration of a heat-resistant polyester film (hereinafter referred to as PE film) was measured as a sample of the insulating material. Accelerated deterioration conditions were stored at 140 ° C. for 5 hours, 200 ° C. for 5 hours, 200 ° C. long-term storage (200 ° C. for about 80 hours) in a constant temperature bath, and the PE film was accelerated and deteriorated. Moreover, an unused PE film was used as a sample before deterioration.

  The method for measuring the degree of deterioration of the sample was performed in the same manner as in Example 1 by the same method as the method for measuring the degree of deterioration using toluene as a solvent shown in FIG. Specifically, in the sample dissolution step S5, 0.01 g of PE film was sampled in a 5 mL volumetric flask, diluted with toluene, and then stirred by ultrasonic vibration for 20 minutes. Then, it left still for 15 minutes in the aluminum bath set to 35 degreeC, and stored in the aluminum bath until just before measuring the viscosity of a solution.

  In the sample dissolution step S5, the PE film stored at 200 ° C. for a long time (about 80 hours at 200 ° C.) was not completely dissolved in the solvent due to a change in molecular structure due to deterioration. Therefore, the intrinsic viscosity of the supernatant of the solution is measured, and the sample that does not dissolve and precipitates is filtered and dried, and then the weight is weighed. The measured weight is subtracted from the collected weight to calculate the concentration of the solution. It was.

  The viscosity measurement step S3 and the deterioration degree determination step S4 were performed on the solution obtained in the sample dissolution step S5, the molecular weight retention of the deteriorated PE film was calculated, and the deterioration degree of the deteriorated PE film was measured. . And like Example 1, in order to confirm that PE film deteriorated because molecular weight retention rate fell, the tensile strength test was done using the same test piece.

  FIG. 18 shows the results of measuring the relationship between the molecular weight retention rate and the tensile strength under the accelerated deterioration conditions of each PE film. It was confirmed that the degradation temperature increased (or the degradation time increased), and the molecular weight retention rate and tensile strength of the PE film decreased. In addition, the PE film which was stored at 200 ° C. for a long time (about 200 hours at 200 ° C.) was significantly deteriorated, and a tensile test could not be performed.

  As described above with reference to specific examples, according to the method for measuring the degree of deterioration of an insulating material of the present invention, the intrinsic viscosity of the solution is calculated based on the viscosity of the solution in which the insulating material is dissolved. Based on the intrinsic viscosity, the degree of deterioration of the insulating material can be measured. As a result, not only when the entire insulating material deteriorates, such as thermal deterioration or hydrolysis, but also when it deteriorates from the surface of the insulating material, such as ultraviolet deterioration, the degree of local deterioration of the insulating material is reduced. It can be measured.

  In addition, the ratio of the intrinsic viscosity of dissolved insulating material to the intrinsic viscosity of the solution in which the insulating material before degradation is dissolved (molecular weight retention) is used as an indicator of the degree of degradation of the insulating material, so that insulation can be easily performed. The degree of deterioration of the material can be determined.

  Further, according to the method for measuring the degree of deterioration of an insulating material of the present invention, the degree of deterioration of many types of insulating materials that can be dissolved in a solvent can be measured.

  Further, according to the method for measuring the degree of deterioration of an insulating material according to the present invention, for example, the degree of deterioration of the insulating material can be measured by collecting a small amount of a sample of about 0.01 g. Therefore, the present invention can be applied to an insulating material that cannot be subjected to a tensile test (or elongation test). For example, it is possible to measure a small plastic product in which a specimen for a tensile test cannot be collected, a degree of deterioration of a minute part where stress is particularly concentrated, and the like. That is, it is possible to measure the degree of deterioration at any place of the plastic product. Furthermore, since there is a high degree of freedom in selecting the part from which the sample for measuring the degree of degradation is collected, the characteristic part is characterized by heat during molding of the insulating material, degradation due to thermal decomposition, hydrolysis, etc. due to residual moisture. The determination of the degree of deterioration can also be made by taking a sample from a part of the plastic product that is characteristic of deterioration.

  When molding a plastic product, the insulating material is naturally heated in order to fill the mold with the insulating material. Insulation material may be decomposed in the same manner as deterioration during molding due to insufficient drying of the insulation material or prolonged heating. The method for measuring deterioration of an insulating material according to the present invention is a method for confirming the decomposition of the insulating material at the time of molding, particularly a portion farthest from the inlet (gate) of the mold, and a portion where stress is easily concentrated such as a screw mounting portion It is also possible to determine the strength (degradation degree) of the.

  Further, according to the method for measuring the degree of deterioration of the insulating material of the present invention, it is impossible to collect a test piece for a tensile test or an elongation test by obtaining a relationship between a molecular weight retention rate and a tensile test or an elongation test in advance. Even for a small plastic product, it is possible to estimate the measurement of deterioration by a tensile test or an elongation test from the measurement result of the molecular weight retention rate. That is, it is possible to set a threshold value for the molecular weight retention rate based on the decrease in the molecular weight retention rate and the decrease in the tensile strength (or elongation), and to determine the lifetime of the insulating material based on the molecular weight retention rate.

  In addition, when the Solomon-Ciuta formula, which is a one-point concentration method, is employed, the degree of deterioration can be calculated by measuring the intrinsic viscosity in a short time and in a short time, so the measurement of the degree of deterioration is called 30 to 45 minutes. It can be measured in a short time.

  In addition, when hexafluoroisopropanol or toluene is used as a solvent for dissolving the insulating material, the intrinsic viscosity can be measured from room temperature to 40 ° C. where the solvent can be handled safely. In particular, since hexafluoroisopropanol has many types of insulating materials that can be dissolved, comparison of measured values and blank measurement are facilitated.

  Moreover, if a sample is sampled several times from the surface of the insulating material every 0.2 to 0.5 mm, the degree of deterioration of the insulating material in the depth direction can be measured. For example, when the surface of the insulating material is particularly deteriorated, such as deterioration due to ultraviolet irradiation, the distribution of the degree of deterioration in the depth direction from the surface of the insulating material can be measured.

  In addition, by determining the relationship between the color of the surface of the sample before deterioration and the surface of the sample after accelerated deterioration, and the change in the molecular weight retention with respect to the change in the color, the deterioration of the insulating material progresses from the color of the deterioration surface. The degree can be estimated. That is, based on the change in the color of the insulating material, it is possible to measure the progress rate of the deterioration of the insulating material inside the sample from the deteriorated surface. In particular, the degradation degree measuring method of the present invention can evaluate the degree of degradation in the vicinity of the surface of the insulating material, so that the correlation between the degree of degradation of the insulating material and the color change of the insulating material can be obtained with high accuracy. .

  Moreover, the degradation degree measuring apparatus of this invention can measure the degradation degree of an insulating material using the degradation degree measuring method of this invention. For example, as shown in FIG. 19, by using a deterioration degree measuring device 7 having a storage means 4, a viscosity measuring means 5, and a deterioration degree measuring means 6, the degree of deterioration of the insulating material can be easily measured. Can do.

  Specifically, each means of the deterioration degree measuring device 7 will be described. The storage means 4 has a relationship between the concentration and viscosity of a solution in which an insulating material before deterioration is dissolved in a predetermined solvent in advance or the insulating material before deterioration is dissolved. It is a means for preserving the intrinsic viscosity of the solution. The viscosity measuring means 5 is a means for measuring the viscosity of the solution in which the insulating material after deterioration is dissolved. The deterioration degree measuring means 6 calculates the intrinsic viscosity of the solution in which the deteriorated insulating material is dissolved based on the viscosity of the solution in which the deteriorated insulating material is dissolved and the concentration of the solution measured by the viscosity measuring means 5. Based on this intrinsic viscosity and the intrinsic viscosity of the solution in which the insulating material before deterioration calculated from the data stored in the storage means 4 is dissolved, the degree of deterioration of the insulating material after deterioration is determined.

  As described above, the deterioration degree measuring device 7 of the present invention stores in advance the intrinsic viscosity (or measurement value capable of calculating the intrinsic viscosity) of the solution in which the insulating material before deterioration is dissolved in the storage unit 4. Based on the viscosity and concentration of the solution in which the insulating material after deterioration is dissolved, the degree of deterioration of the insulating material after deterioration can be easily determined.

  As described above, the deterioration degree measuring method and the deterioration degree measuring apparatus of the insulating material according to the present invention have been described in detail with specific examples. However, the deterioration degree measuring method and the deterioration degree measuring apparatus of the insulating material according to the present invention are described above. Not only the form but also the design can be changed as appropriate without departing from the characteristics of the present invention, and such a modified form also belongs to the technical scope of the present invention.

  For example, since the insulating material of the present invention can be applied as long as it is an insulating material that can be dissolved in a solvent, the insulating material for determining the degree of deterioration is not limited to the embodiment, and various insulating materials deteriorate. It can be applied to measure the degree. As a solvent for dissolving the insulating material, a solvent capable of dissolving the insulating material is appropriately selected according to the insulating material.

  In addition, although the intrinsic viscosity is calculated based on the concentration and viscosity of the solution in which the insulating material is dissolved, the calculation method of the intrinsic viscosity of the solution in which the insulating material is dissolved is limited to calculation based on the Solomon-Ciuta equation. However, other intrinsic viscosity calculation methods may be used.

  In addition, although the degree of deterioration can be easily measured by determining the degree of deterioration of the insulating material based on the molecular weight retention rate, the degree of deterioration of the insulating material may be directly determined based on the intrinsic viscosity value of the solution. .

  Further, the viscosity of the solution in which the insulating material is dissolved can be appropriately measured using a known viscosity measuring method, and the insulating material can be evaluated based on the measured viscosity using a known viscosity measuring method. . However, by using a falling body type viscosity measurement method as a method for measuring the viscosity of a solution, it is possible to perform measurement with a very small amount of sample, and to perform highly accurate and reproducible measurement, which is sealed. There are advantages such as prevention of contact with air and accurate temperature control. In particular, by using a falling body type viscosity measurement method, a small amount of sample is required for viscosity measurement. As a result, the sample can be collected in a layered manner and the degree of deterioration of the sample can be evaluated.

DESCRIPTION OF SYMBOLS 1 ... Test piece 2 ... Capillary 3 ... Ball 4 ... Storage means 5 ... Viscosity measuring means 6 ... Deterioration degree measuring means 7 ... Deterioration degree measuring device

Claims (9)

A method for measuring the degree of deterioration of an insulating material,
Dissolve the initial insulating material in a solvent, measure the viscosity of this solution,
Dissolve the insulating material after deterioration for a predetermined time in a solvent, measure the viscosity of this solution,
The degree of deterioration of the insulating material after deterioration is determined based on the viscosity of the solution in which the insulating material in the initial state is dissolved and the viscosity of the solution in which the insulating material after deterioration is dissolved. Degradation measurement method. Based on the measurement result of the viscosity of the solution, calculate the intrinsic viscosity of the solution,
The degree of deterioration of the deteriorated insulating material is determined based on the intrinsic viscosity of the solution in which the insulating material in the initial state is dissolved and the intrinsic viscosity of the solution in which the insulating material after the deterioration is dissolved. Item 2. A method for measuring the degree of deterioration of an insulating material according to Item 1. Calculate the ratio of the intrinsic viscosity of the solution in which the insulating material after degradation to the intrinsic viscosity of the solution in which the insulating material in the initial state is dissolved as a molecular weight retention rate,
The method for measuring a degree of deterioration of an insulating material according to claim 2, wherein the degree of deterioration of the insulating material after the deterioration is determined based on the molecular weight retention rate. 4. The method according to claim 1, wherein the deterioration degree of the insulating material after the deterioration is determined every 0.2 to 0.5 mm from the surface of the insulating material. 5. Deterioration degree measuring method for the described insulating material. The viscosity is measured by a falling body viscosity method,
The deterioration of the insulating material according to any one of claims 1 to 4, wherein in the falling body viscosity method, an inclination angle of a capillary for holding the solution is in a range of 30 ° to 70 °. Degree measurement method. 6. The method for measuring a deterioration level of an insulating material according to claim 2, wherein the intrinsic viscosity is calculated based on a Solomon-Ciuta equation. The solvent is hexafluoroisopropanol;
The method for measuring a degree of deterioration of an insulating material according to any one of claims 1 to 6, wherein when the insulating material does not dissolve in hexafluoroisopropanol, the solvent is toluene. Correlating the degree of deterioration determined based on the viscosity of the solution in which the insulating material after deterioration is dissolved, and the color of the insulating material after deterioration,
The method for measuring a degree of deterioration of an insulating material according to any one of claims 1 to 7, wherein the degree of deterioration of the insulating material is determined based on a color of the insulating material. Storage means for storing the intrinsic viscosity of the solution in which the insulating material in the initial state is dissolved;
Means for measuring the viscosity of a solution in which the insulating material is degraded after a predetermined time;
Based on the intrinsic viscosity of the solution in which the insulating material in the initial state is dissolved and the intrinsic viscosity calculated based on the viscosity of the solution in which the insulating material after deterioration is dissolved, the degree of deterioration of the insulating material after deterioration is determined. And a means for determining the deterioration level of the insulating material.