JP5702547B2 - Chlorine resistance evaluation method and evaluation apparatus for polymer materials - Google Patents

Description

  The present invention relates to a method for evaluating chlorine resistance of a polymer material such as a rubber material and an evaluation apparatus therefor.

  Conventionally, a rubber material, which is one of polymer materials, has been widely used as a sealing member for O-rings, packings, gaskets and the like of water supply equipment. When a rubber material is used as a seal member for water supply equipment, the rubber material is likely to deteriorate due to the oxidizing power of free residual chlorine contained in tap water. When the rubber material deteriorates, the strength of the rubber material becomes weaker, and the so-called black powder phenomenon (inkbrush) that the fine rubber pieces containing carbon black for improving the strength normally contained in the rubber material are separated and mixed into the tap water. Phenomenon). In particular, when the rubber material forms a dynamic seal member that repeats friction such as an O-ring of a valve stem and a seat rubber of a butterfly valve, durability is required, and thus higher chlorine resistance is required. . For this reason, a polymer material such as a rubber material including this type of dynamic seal member is often evaluated by a chlorine resistance test as compared with a static seal member.

  As a chlorine resistance test, first, a rubber material is processed into a test piece having a predetermined shape, and in order to accelerate the deterioration of the test piece, the test piece is generally immersed in an aqueous sodium hypochlorite solution. In some cases, a tensile strength test, a tensile elongation test, and a modulus (predetermined elongation tensile stress) test are performed on each test piece before and after the immersion. Since these tests are destructive tests, it is necessary to prepare a necessary number of test pieces in advance and immerse all the test pieces. During testing, the hardness, weight change rate (change in water supply rate), specific gravity change rate, and appearance change of the test piece may be measured. Further, as the appearance change, the surface of the test piece may be measured with an appropriate force. There are cases where the surface change is determined by observing the surface with a so-called cotton swab test, or by observing the surface with an electron microscope. Of these, the swab test is often used as a general test method in industrial associations and academic societies because it is relatively easy to judge the results of the test and to easily check changes during the test. Yes.

  On the other hand, as a chlorine resistance test, the color change of the aqueous solution in which the test piece is immersed may be measured visually. For example, the black powder phenomenon described above is evaluated by comparison with a judgment standard in which the color intensity is divided into several stages by this visual measurement test. FIG. 6 shows a state in which the color of the aqueous solution changes when the test piece is provided in a dumbbell shape conforming to JIS K 6251 and immersed in an aqueous solution of sodium hypochlorite having two concentrations. .

As this type of chlorine resistance test, for example, a polymer material evaluation method described in Patent Document 1 has been proposed. In this polymer material evaluation method, a polymer material is brought into contact with a test solution containing free chlorine, and the chlorine-resistant water resistance of the polymer material is evaluated by a change with time of cracks on the surface of the polymer material.
Patent Document 2 discloses a chlorine-resistant rubber composition. Among these, as a chlorine resistance evaluation test of a rubber composition, a carbon-containing material release evaluation test of a rubber test piece and a visual inspection of an immersion liquid are disclosed. A pollution assessment test is described.

JP-A-2005-351768 Japanese Patent No. 4082978

However, in the above-mentioned chlorine resistance test and the tests in Patent Documents 1 and 2, when performing a tensile strength test, a tensile elongation test, and a modulus test of the test piece, a plurality of test pieces are required for measurement before and after the test. Therefore, the number of tests is limited, and a large number of test pieces are required to increase the number of tests. In addition, since this test method tends to increase the error of the test result, more test pieces are required for each test.
Furthermore, it took time and effort to take out the test piece from the test apparatus each time and to carry out various tests, and to maintain the concentration of the aqueous solution in order to prevent a decrease in the chlorine water concentration due to immersion of the test piece.

  Also, when measuring the hardness of a test piece during a test, the error tends to increase due to the characteristics of the test. Furthermore, the shape of the test piece is usually defined. For example, since the test piece is prescribed in a dumbbell shape in the test method in JIS standard, an O-ring actually used other than this shape is measured. This has become practically difficult. When measuring the rate of change in weight and the change in specific gravity, due to the characteristics of the test, only a slight difference can be measured, and if the test piece falls off or is lost due to prolonged immersion, the measurement results May cause a large measurement error. When measuring with a cotton swab test or observing changes in appearance, the determination means is a stepwise evaluation by visual inspection, so that the variation among the measurers increases and an error occurs, and the observation takes time.

  Moreover, there is no correlation between the test results of the commonly used swab test and the test results that can be quantitatively evaluated such as tensile strength, tensile elongation, and modulus test. It is hard to say that the chlorine resistance is accurately evaluated from the test results. For example, even when the amount of black deposits attached in a cotton swab test is small, the strength such as tensile strength may be weak, or even when the strength is high, the amount of black deposits attached may be large. The reason for this is that a rubber material containing carbon black, when containing carbon black with a large particle size, makes it difficult for the carbon to precipitate, but its strength is weakened. This is because the powder has the contradictory characteristics that the powder is easily generated but the strength is increased.

In the test to measure the color change of the aqueous solution in which the test piece is immersed, the measurement result is ambiguous because it is judged visually, and it is difficult to judge the result quantitatively. . For example, in FIG. 6, it is not possible to quantitatively judge a subtle shade difference in color with the passage of time of the aqueous solutions A and B in which different test pieces are immersed. Moreover, with this test method, it is difficult to test a rubber material that does not contain carbon black.
From these facts, the test method for directly measuring the chlorine resistance of the polymer material has low reliability, and it is difficult to accurately determine the chlorine resistance of the test piece in any test. For this reason, it is not preferable to evaluate a sealing material used under more severe conditions such as a dynamic sealing member in these tests.

  The present invention has been developed as a result of intensive studies in view of the above circumstances, and the object of the present invention is to perform quantitative and continuous tests without directly measuring polymer materials. An object of the present invention is to provide a method for evaluating the chlorine resistance of a polymer material and an apparatus for evaluating the same, which can accurately evaluate the chlorine resistance of a molecular material.

In order to achieve the above object, the invention according to claim 1 includes an aqueous solution supplying step of supplying a chlorine-based aqueous solution having a predetermined concentration in a state where the polymer material is stored in a predetermined storage portion, and the polymer material is contained in the aqueous solution. In this repetition, an immersion step for immersing for a predetermined time, a measurement step for measuring the free residual chlorine concentration of the aqueous solution after a predetermined time, and a discharge step for discharging the aqueous solution in order to replace the aqueous solution after the measurement are repeated. A method for evaluating the chlorine resistance of a polymer material, wherein the concentration of free residual chlorine in the aqueous solution is continuously measured for each measurement in the measurement step, and the chlorine resistance of the polymer material is evaluated based on the measurement result. It is.

  The invention according to claim 2 is a chlorine resistance evaluation method for a polymer material in which the free residual chlorine concentration of an aqueous solution is measured by a diethyl-p-phenylenediamine method.

  The invention according to claim 3 is that the polymer materials are individually stored, and each polymer material is immersed in an aqueous solution to evaluate the chlorine resistance of a plurality of polymer materials at once. This is a sex evaluation method.

  In the invention according to claim 4, the relationship between the immersion time of the polymer material and the measured value of the free residual chlorine concentration of the aqueous solution is subjected to regression analysis, and the chlorine resistance is evaluated based on the regression analysis result. This is a chlorine resistance evaluation method.

  The invention according to claim 5 is a storage unit having a predetermined capacity for storing the polymer material and storing the chlorinated aqueous solution in which the polymer material is immersed in an exchangeable manner, and the free residue of the aqueous solution in which the polymer material is immersed. This is a chlorine resistance evaluation apparatus for a polymer material having a detection unit that continuously measures the chlorine concentration and a control unit that evaluates the chlorine resistance of the polymer material from the measurement result of the detection unit.

  According to the first aspect of the present invention, the polymer material is immersed in a chlorine-based aqueous solution in a state where the polymer material is stored in a storage unit having a predetermined capacity, and the concentration of free residual chlorine is continuously measured every time the aqueous solution is replaced. Since the chlorine resistance of molecular materials is evaluated, it is possible to accurately evaluate the chlorine resistance of polymer materials by quantitatively and continuously testing aqueous solutions without directly measuring the chlorine resistance of polymer materials. . For this reason, it is possible to easily measure the free residual chlorine concentration with a small number of procedures without requiring an extra polymer material for measurement. Furthermore, since a polymer material in the form of a product such as an O-ring attached to the product can be used as it is as a test piece, the procedure can be simplified and the evaluation can be performed under conditions close to actual use conditions.

  According to the second aspect of the present invention, free residual chlorine concentration can be measured by using a commonly used method for measuring an aqueous solution, and an artificial error can be minimized by quantitatively measuring the deterioration state of the polymer material. Evaluation can be performed without limiting the number of tests.

  According to the third aspect of the invention, the chlorine resistance of polymer materials having different materials and shapes can be simultaneously evaluated, and many types of polymer materials can be evaluated at once in a short time while simplifying the equipment.

  According to the invention which concerns on Claim 4, the relationship between immersion time and residual chlorine concentration can be derived by graphing a measured value by regression analysis, and evaluation of chlorine resistance for every polymer material becomes easy. Furthermore, since the relationship between the immersion time after measurement and the residual chlorine concentration can be graphed, the lifetime of the polymer material can be predicted.

  According to the invention according to claim 5, since the chlorine resistance of the polymer material can be evaluated by measuring the chlorinated aqueous solution by the storage unit, the detection unit, and the control unit, the quantitative measurement can be performed without directly measuring the polymer material. Continuous tests can be performed to accurately evaluate the chlorine resistance of the polymeric material. In addition, the entire facility can be simplified and downsized, and at the time of testing, it is a device that can easily measure the free residual chlorine concentration with few procedures without requiring extra polymer materials for measurement. .

It is a flowchart of embodiment of the chlorine resistance evaluation method of the polymeric material in this invention. It is a schematic diagram of a chlorine resistance evaluation apparatus. It is the schematic which showed an example of the chlorine resistance evaluation apparatus. It is the graph which showed the measurement result of residual chlorine concentration. It is the photograph which showed the result of the cotton swab test. It is the photograph which showed the change of the color of the aqueous solution in a chlorine resistance test.

  DESCRIPTION OF EMBODIMENTS Embodiments of a method for evaluating chlorine resistance of a polymer material and an apparatus for evaluating the same according to the present invention will be described below in detail with reference to the drawings. In FIG. 1, the flowchart of the chlorine resistance evaluation method of the polymeric material of this invention is shown, and FIG. 2 has shown the schematic diagram of the chlorine resistance evaluation apparatus. For convenience, a chlorine resistance evaluation apparatus will be described first.

  In FIG. 2, an evaluation apparatus main body (hereinafter referred to as “apparatus main body”) 1 has at least a storage unit 2, a detection unit 3, and a control unit 4, and in this embodiment, in addition to these, an input unit 5. , An input device 6, a display unit 7, and a display device 8. The storage unit 2 has a plurality of storage containers 10 formed in an appropriate shape, and the storage container 10 is an aqueous solution tank of FIG. 3 to be described later in which a chlorine-based aqueous solution (hereinafter referred to as an aqueous solution) 11 having a predetermined concentration is accumulated. 12 connected in parallel.

The storage container 10 can individually store the polymer material 13 therein, and stores the aqueous solution 11 when the aqueous solution 11 is sent from the aqueous solution tank 12 so that the polymer material 13 is immersed therein. It has become. The aqueous solution 11 stored in the storage container 10 can be exchanged as necessary. The aqueous solution 11 may be a liquid having free radicals, and is preferably sodium hypochlorite which is chlorine water. An aqueous solution is used. The density | concentration of the aqueous solution 11 is set to the conditions of 1-500 ppm which is 0.1-1 ppm or more which is the chlorine concentration of the tap water generally prescribed | regulated, The density | concentration is kept constant.
On the other hand, the polymer material 13 is a polymer material having chain molecules in which basic molecules (monomers) are connected by covalent bonds. Although any kind of polymer material 13 can be used, the polymer material of this example is made of a rubber material such as an O-ring for water supply equipment containing a carbon component.

  The detection unit 3 is connected to the storage container 10 so that the state of the aqueous solution 11 in the storage container 10 can be measured, and has a concentration sensor (not shown). The concentration sensor can measure the free residual chlorine concentration of the aqueous solution 11 after the polymer material 13 is immersed before the replacement. In addition to the concentration sensor, the detection unit 3 includes a pH sensor, a temperature sensor, a flow rate sensor, a liquid amount sensor, a pressure sensor, and a timer (not shown), and a timer (not shown) uses a timer (central processing unit). Has a detection function for measuring the pH, temperature, flow rate, liquid volume, and pressure of the aqueous solution 11 every predetermined time. Among these, the concentration sensor, pH sensor, temperature sensor, liquid amount sensor, pressure sensor, and timer are necessary for managing the state of the aqueous solution 11, and the flow rate sensor performs the test while continuously flowing the aqueous solution 11. It is necessary to do this and is optional depending on the implementation.

  The control unit 4 is connected to the detection unit 3, can control each sensor and timer of the detection unit 3, and includes a CPU (not shown) and a memory that form a personal computer (personal computer) main body (not shown) together with the input unit 5 and the display unit 7. Provided by a component such as a hard disk. The control unit 4 includes an accumulation function for accumulating data of various measurement results (measurement data) measured by the detection unit 3 by the CPU and data (collection data) collected from an actual usage environment, and various measurement data. It has a calculation function for evaluating the chlorine resistance of the polymer material 13.

  The measurement data accumulated in the control unit 4 includes concentration data by the concentration sensor, pH condition data by the pH sensor, temperature condition data by the temperature sensor, flow rate data by the flow sensor, liquid amount data by the liquid amount sensor, There are immersion time data by a timer, pressure condition data by a pressure sensor, and the like. On the other hand, as the calculation performed by the calculation function, a regression analysis of the relationship between the immersion time of the polymer material 13 and the measurement data of the free residual chlorine concentration of the aqueous solution 11, a calculation for graphing the result of the regression analysis, There are calculations for calculating durability from the results of regression analysis, and calculations for comparing the measured data with the collected data to obtain the lifetime. Thereby, the control unit 4 can evaluate the chlorine resistance of the polymer material 13 from various measurement data obtained by the detection unit 3. Here, the term “lifetime” refers to a period until the black powder phenomenon or the ink phenomenon occurs in the polymer material.

The input unit 5 is connected to the control unit 4, and various information is input from the input device 6 such as a keyboard connected to the input unit 5 and accumulated in the control unit 4. This information includes collected data such as concentration, pH, temperature, flow rate, soaking time, pressure, etc., calculation for regression analysis from measurement data of free residual chlorine concentration, and calculation / lifetime when evaluating durability There are comparison arithmetic coefficients and mathematical formulas for prediction.
Similarly to the input unit 5, the display unit 7 is connected to the control unit 4, and a screen for inputting data, calculation results, a graph, and the like are displayed on the display 8 that is a display device connected to the display unit 7.

  FIG. 3 shows an example in which the evaluation apparatus of FIG. 2 is more concretely used in actual use. The apparatus main body 1 includes a chemical solution adjusting unit 15 and an aqueous solution tank 12 in addition to the above-described units. The chemical liquid adjusting unit 15 and the aqueous solution tank 12 are connected to the apparatus main body 1 by an aqueous solution flow path 17 and electrically connected by a control circuit 18.

The chemical liquid adjusting unit 15 includes, for example, a chemical liquid tank 21 for storing H ₂ O (water) and a chemical liquid tank 22 for storing HCl (dilute hydrochloric acid) in addition to a chemical liquid tank 20 that stores an aqueous NaOCl (sodium hypochlorite) solution. , A chemical tank 23 for storing an aqueous solution of NaOH (sodium hydroxide), and a detection unit 24, and each chemical liquid is stored in a high concentration state in each chemical tank 20, 21, 22, 23. . H ₂ O is added to adjust the concentration, and an aqueous HCl solution and an aqueous NaOH solution are added to adjust the pH. Since the commercially available NaOCl aqueous solution is in a high concentration state of, for example, about 50000 ppm, the adjustment of the solution components is performed in this way as necessary.

  The chemical liquid tanks 20, 21, 22, and 23 are connected to the aqueous solution tank 12 through the aqueous solution flow path 17. The detection unit 24 is provided at this junction, and the chemical liquid tanks 20, 21, 22, 23 and the detection unit 24 are connected by the aqueous solution flow path 17 and the control circuit 18. Each chemical solution tank 20, 21, 22, 23 is provided with pumps 25, 26, 27, 28 for sending the chemical solution to the detection unit 24.

Similarly to the detection unit, the detection unit 24 includes a concentration sensor (not shown), a pH sensor, a temperature sensor, a flow rate sensor, a liquid amount sensor, a pressure sensor, and a timer, and each measurement of the aqueous solution 11 is performed every predetermined time by the timer. Data can be measured. Thereby, the chemical solution adjusting unit 15 supplies the chemical solution from the chemical solution tanks 20, 21, 22, 23 to the aqueous solution tank 12 while managing it. At this time, the detection unit 24 is controlled by the control unit 4. The necessity of each sensor is the same as that of the detection unit 3.
In the aqueous solution tank 12, the aqueous solution 11 mixed with the chemical solutions from the chemical solution tanks 20, 21, 22, and 23 is accumulated in a predetermined management state. The aqueous solution tank 12 is provided with a mantle heater (not shown), and the aqueous solution 11 is kept at a predetermined temperature by the mantle heater.

  The aqueous solution tank 12 is connected to the storage unit 2 by an aqueous solution channel 17 through a pump 29 and a valve 30. The storage unit 2 in this example includes three storage containers 10 and can further maintain the temperature of the aqueous solution 11 by a heat insulating heater (not shown). The storage unit 2 is connected to the detection unit 3 by the control circuit 18, and the detection unit 3 detects measurement data such as the concentration of the aqueous solution 11 in the storage container 10. As described above, the detection unit 3 is connected to the control unit 4 and controlled by the control unit 4. A discharge channel 31 is provided on the secondary side of the detection unit 3, and the measured aqueous solution 11 is discharged to the outside through the discharge channel 31.

  The test apparatus described above is merely an example, and includes a storage unit 2, a detection unit 3, and a control unit 4. The storage unit 2 has a predetermined volume, and the polymer material 13 is replaced with a predetermined amount of the aqueous solution 11. The solution 11 can be stored while being immersed, and the aqueous solution 11 can be exchanged. The detection unit 3 can continuously measure the free residual chlorine concentration every time the aqueous solution 11 is exchanged. As long as the chlorine resistance of the polymer material 13 can be evaluated, the mode is arbitrary depending on the implementation.

  The polymer material 13 may be other than a rubber material, and may be, for example, a thermoplastic elastomer material or a resin material as long as the material has a polymer structure in which basic molecules are connected by covalent bonds. Further, the liquid in which the polymer material 13 is immersed may be other than the chlorine-based aqueous solution 13, such as hydrogen peroxide, ozone, peracids, persalts, hypohalous acids, hypohalites, etc. An oxidizing agent having free radicals can also be used as appropriate. In this case as well, the oxidation resistance of a polymer material such as a rubber material can be evaluated by measuring the ion concentration or acid concentration in the solution, as in the case of evaluating the chlorine resistance with the chlorinated aqueous solution 13. .

  Next, a method for evaluating the chlorine resistance of a polymer material using the above-described evaluation apparatus will be described. FIG. 1 shows a flowchart of an embodiment of the method for evaluating chlorine resistance of a polymer material of the present invention. In this embodiment, the aqueous solution supply step S1, the polymer material immersion step S2, the immersion time confirmation step S3, the free residual chlorine concentration measurement step S4, the aqueous solution discharge step S5, the measurement frequency confirmation step S6, and the chlorine resistance evaluation Step S7 is included.

In FIG. 3, polymer materials 13 made of rubber materials of various shapes are separately stored in each storage container 10 of the storage unit 2.
When the apparatus main body 1 is operated in the aqueous solution supply step S1, the NaOCl aqueous solution, H ₂ O, HCl aqueous solution, and NaOH aqueous solution stored in the chemical tanks 20, 21, 22, and 23 are pumped by the pumps 25, 26, 27, and 28. The solution is sent to the aqueous solution tank 12 through the aqueous solution channel 17. At this time, each chemical solution is supplied in a predetermined amount while its concentration is controlled by the concentration sensor of the control unit 4. Among the chemical solutions, the NaOCl aqueous solution is essential for evaluating the chlorine resistance of the polymer material 13, but the supply amount of the remaining aqueous solution can be arbitrarily set.

  Concentration, pH, temperature, and the like of the aqueous solution 11 in the aqueous solution tank 12 and the chemical solutions in the chemical solution tanks 20, 21, 22, and 23 are measured by various sensors, and these numerical values are managed by the control unit 4. As a result, the concentration of the aqueous solution 11 in the aqueous solution tank 12 is controlled to a predetermined value.

  Subsequently, in the polymer material dipping step S <b> 2, the aqueous solution 11 in the aqueous solution tank 12 is supplied to the polymer material 13 through the aqueous solution flow path 17, thereby the polymer material 13 in each storage container 10. Is immersed.

When the polymer material 13 is immersed, the “polymer material surface area (cm ² ): amount of aqueous solution (mL) so that the polymer material 13 has a predetermined surface area relative to the amount of the aqueous solution 11 in the storage container 10. ) "Must be set to an appropriate value. In this embodiment, JIS K 62513 dumbbell pieces × 3 pieces (116 cm ² ) are immersed in 500 mL of an aqueous solution to obtain a surface area / amount of aqueous solution ratio of 232 cm ² / L. For example, the ratio of surface area / amount of aqueous solution of 68 cm ² / L may be used, and this ratio is not limited to a specific value and may be within a predetermined range. In this case, if the surface area is provided in an area that can be compared with the collected data, the shape is not limited, and thus any shape other than the dumbbell shape can be used.

  Therefore, if the surface area with respect to the amount of the aqueous solution 11 is specified, the polymer material 13 may have any shape, not only a seal member such as an O-ring, packing, or gasket used in a product or an existing test piece, A polymer material having no specific shape such as a fragment portion can also be used. Furthermore, since the conditions can be unified by the ratio of the surface area of the polymer material 13 and the amount of the aqueous solution 11, for example, it becomes possible to compare the chlorine resistance of a plate-shaped test piece and an O-ring having the same ratio. This ratio is set to an appropriate value for each type of polymer material 13.

  In the immersion time confirmation step S3, the aqueous solution 11 of the storage container 10 is immersed until the set immersion time is reached while the immersion time is confirmed. As immersion time at this time, 24 hours is preferable, for example. A supply / discharge cycle of the aqueous solution 11 is input in advance to the input unit 5 from the input device 6, and the aqueous solution 11 is accumulated in the storage container 10 until a predetermined time elapses.

When the immersion time reaches a predetermined time, the free residual chlorine concentration and the like of the aqueous solution 11 in which each polymer material 13 is immersed by the various sensors of the detection unit 3 are separately measured by the detection unit 3 in the measurement step S4 of the free residual chlorine concentration. Is done. At this time, the status of the polymer material 13 and the like are input in advance to the input unit 5 from the input device 6 as collected data. In this manner, the chlorine resistance and the like are confirmed for each polymer material 13 stored in each storage container 10, and a plurality of polymer materials 13 are measured at a time.
When the measurement is completed, the aqueous solution 11 is discharged from the storage container 10 in the aqueous solution discharge step S5.

The above-mentioned measurement is counted in the measurement number confirmation step S6, and when this measurement number has not reached the preset measurement number, the steps from the aqueous solution supply step S1 to the aqueous solution discharge step S5 are repeated again. As a result, the concentration of the aqueous solution and the like are continuously measured, and when the predetermined number of measurements is reached, the measurement is terminated.
Subsequently, in the chlorine resistance evaluation step S7, the chlorine resistance is evaluated from the measurement results continuously measured.

  As described above, in the evaluation method of the present invention, the polymer material 13 is immersed in the aqueous solution 11 having a predetermined concentration in a state in which the polymer material 13 is stored in the storage unit 2 (storage container 19) having a predetermined capacity. The free residual chlorine concentration is continuously measured for each aqueous solution 11 at the time of replacement, and the chlorine resistance of the polymer material 13 is evaluated from the measurement result. From this measurement result, for example, the free residual chlorine concentration of different polymer materials 13 in a predetermined immersion time is compared, or the decrease rate of the residual chlorine concentration with respect to the passage of immersion time is compared for each polymer material 13. Thus, the chlorine resistance of the polymer material 13 can be evaluated. For example, when the concentration of free residual chlorine is high for a predetermined immersion time, it is determined that the polymer material 13 has not adsorbed or decomposed chlorine, and it can be evaluated that the chlorine resistance of the polymer material 13 is high.

  At this time, the free residual chlorine concentration of the aqueous solution 11 is measured by the diethyl-p-phenylenediamine method (DPD method). The DPD method is an inspection method in which a reagent of diethyl-p-phenylenediamine is mixed in the aqueous solution 11, and the free residual chlorine concentration is calculated from the color density, and measurement such as a ready-made colorimetric or digital method is not shown. The free residual chlorine concentration can be measured easily and accurately using a vessel.

  The measurement data collected by the detection unit 3 and the detection unit 24 is sent to the control unit 4, and the free residual chlorine concentration of the aqueous solution 11 with respect to the immersion time of the polymer material 13 is collected for a certain period. The collected measurement data is subjected to regression analysis by, for example, logarithmic calculation by the CPU of the personal computer, and is graphed as shown in FIG. Thus, chlorine resistance is quantified by graphing the relationship between the immersion time and the residual chlorine concentration for each polymer material 13.

  In this case, it is also possible to predict the lifetime of the polymer material 13 by comparing the regression curve / measurement data of the graph and the collected data. At that time, it is preferable to input the measured life obtained from the water pipe or the like used in the actual site from the input device 6 and use this as a correction value for the life calculation. The operator can confirm the evaluation result, the measurement data and the collected data, and various situations at the time of evaluation by visually checking the display 8.

  As described above, the method for evaluating chlorine resistance of a polymer material according to the present invention measures the aqueous solution 11 that is a solvent in which the polymer material 13 is immersed, and therefore directly measures the test piece of the polymer material 13. There is no need for a large amount of polymer material test piece, and no error or variation due to the test piece. Furthermore, since the number of tests is not limited, it does not take time. According to this evaluation method, the chlorine resistance is evaluated using the aqueous solution 11 exchanged every predetermined time, so that the test can be carried out quantitatively and continuously, and the free residual chlorine concentration can be measured as a numerical value. Therefore, the chlorine resistance of the polymer material 13 can be accurately evaluated.

  Moreover, the evaluation method of the present invention has a high correlation with the cotton swab test, and the superiority of chlorine resistance when the blending ratio of carbon black to the rubber material is changed. Can be confirmed quantitatively. For example, when a filler (reinforcing agent) is blended with the base rubber material at 5 phr (parts by weight), 10 phr, and 15 phr, it is difficult to grasp the performance difference depending on the blending amount in the swab test, and the optimum addition amount is specified. However, according to the evaluation method of the present invention, it is possible to quickly confirm the optimum value of the filler blending amount while obtaining the same chlorine resistance result as the cotton swab test.

  When blending expensive fillers into rubber materials, the properties of the rubber material may change greatly or slightly due to slight differences in the amount added, and even if this change in properties is slight, the anti-aging agent As a rubber material, the performance may be greatly improved due to the interaction with other additives. According to the evaluation method of the present invention, from the above, it becomes easier to grasp this slight advantage compared with the cotton swab test, so that the accuracy is improved as a method for evaluating the chlorine resistance of the polymer material. The speed when conducting the test is also improved.

  Next, rubber sealing materials having different carbon black blending ratios were evaluated by the chlorine resistance evaluation method for the polymer material of the present invention and a cotton swab test, and the results were compared. 4 and 5, comparative product 1 is a rubber sealing material containing carbon black having a relatively small particle size, and comparative product 2 is carbon black having a relatively large particle size. -3 are made of a rubber sealing material in which a carbon material having higher chlorine resistance than the comparative products 1 and 2 is blended. The evaluation method and the swab test described above were performed on the comparative products 1 and 2 and the test samples 1 to 3. For the swab test, a swab of the same material was used, and this swab was applied to the comparison products 1 and 2 and the test samples 1 to 3 at an angle of 45 °, and the same distance was applied three times for each with a force of 100 N. I rubbed it.

  In FIG. 4, the measured value of the free residual chlorine concentration with respect to the immersion time is plotted by the evaluation method of the present invention, and logarithmic regression analysis is performed from each plotted point, and the logarithmic regression curve is shown. As shown in this graph, the free residual chlorine concentration in the test samples 1 to 3 is higher than that of the comparative products 1 and 2, and it can be easily confirmed by the logarithmic regression curve that the chlorine resistance is high. Thus, when the evaluation method is represented by a logarithmic regression curve, the chlorine resistance of the polymer materials can be easily compared.

On the other hand, in FIG. 5, the result of the cotton swab test is shown. From the figure, the cotton swabs rubbed with the specimens 1 to 3 have less carbon adhesion than the swabs rubbed with the comparative articles 1 and 2, so that the specimens 1 to 3 are the comparative specimens 1 and 2. It is shown that the chlorine resistance is higher than
From these things, it was confirmed that there is a high correlation between the results of the evaluation method of the present invention and the swab test. Furthermore, comparing the test results of the evaluation method of the present invention and the swab test, FIG. 4 shows that the chlorine resistance of each polymer material is quantitatively and continuously shown by a logarithmic regression curve. In No. 5, it is necessary to visually check the carbon adhesion of each polymer material. For this reason, in the swab test, it is difficult to compare specimens and comparative products at the same test time, and it is difficult to confirm the degree of increase in carbon adhesion with respect to the test time of the same specimen or comparative product. . From this result, it was confirmed that the evaluation method of the present invention is superior to the swab test.

DESCRIPTION OF SYMBOLS 1 Apparatus main body 2 Storage part 3 Detection part 4 Control part 10 Storage container 11 Chlorine-based aqueous solution 13 Polymer material

Claims (5)

An aqueous solution supplying step of supplying a chlorine-based aqueous solution having a predetermined concentration in a state where the polymer material is stored in a predetermined storage portion, an immersing step of immersing the polymer material in the aqueous solution for a predetermined time, and releasing the aqueous solution after the predetermined time A measurement step for measuring the residual chlorine concentration and a discharge step for discharging the aqueous solution in order to exchange the aqueous solution after measurement are repeated a predetermined number of times, and free residual chlorine in the aqueous solution is measured at each measurement in the measurement step in this repetition. A method for evaluating the chlorine resistance of a polymer material, wherein the concentration is continuously measured, and the chlorine resistance of the polymer material is evaluated based on the measurement result.   The method for evaluating chlorine resistance of a polymer material according to claim 1, wherein the concentration of free residual chlorine in the aqueous solution is measured by a diethyl-p-phenylenediamine method.   The polymer material according to claim 1 or 2, wherein the polymer materials are individually stored, and each polymer material is immersed in the aqueous solution to evaluate the chlorine resistance of a plurality of polymer materials at a time. Chlorine resistance evaluation method.   The regression analysis of the relationship between the immersion time of the said polymer material and the measured value of the free residual chlorine concentration of the said aqueous solution, Chlorine resistance is evaluated from this regression analysis result. The chlorine resistance evaluation method for the polymer material described in 1.   Continuously measures the free residual chlorine concentration of the aqueous solution in which the polymer material is stored and the chlorine-based aqueous solution in which the polymer material is immersed is exchangeably stored, and the aqueous solution in which the polymer material is immersed And a control unit for evaluating the chlorine resistance of the polymer material from the measurement result of the detection unit.

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