Method for evaluating degree of deterioration of wire coating

Abstract

To provide a method for evaluating the degradation degree of an electric wire coating that can be easily used in a set site without taking a sample of the electric wire coating from the set site.SOLUTION: A method for evaluating the degradation degree of an electric wire coating including polyvinyl chloride and a plasticizer includes, in the stated order, step (1) of attaining a contact unit by bringing an alcoholic solution of a dye in contact with the electric wire coating, and step (2) of evaluating the degradation degree of the electric wire coating on the basis of the degree of coloring of the contact unit.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a method for evaluating the degree of deterioration of an electric wire coating, and particularly to a method for evaluating the degree of deterioration of an electric wire coating containing polyvinyl chloride and a plasticizer.

Background Art

[0002] Conventionally, polyvinyl chloride insulated electric wires (for example, IV electric wires) are well known as insulated electric wires used for general electrical workpieces, wiring for electrical equipment, wiring inside panels, and the like. Since the electric wire coating of such insulated electric wires can cause the electric wire itself to harden or leakage due to aging deterioration, it is necessary to confirm the degree of deterioration of the electric wire coating (mainly the degree of hardening deterioration) in a timely manner.

[0003] As a method for confirming the degree of deterioration of an electric wire coating, for example, there is a method of performing a tensile test on a sample of the electric wire coating taken back from the installation site using an autograph and confirming it by the elongation at break. In this regard, for example, in paragraph

[0015] of Patent Document 1, regarding the elongation at break [%] described in the JIS standard, "The elongation at break refers to the elongation rate at the time of cutting when the electric wire coating with a reference length L0 is pulled. When the length at the time of cutting is L1, the elongation at break is expressed by the formula 'elongation at break = ((L1 - L0) / L0 × 100)'. If the judged elongation at break is less than, for example, 100%, the electric wire does not meet the standard (is deteriorated). " is described.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the method of performing a tensile test on a sample of wire coating and confirming the degree of deterioration based on the elongation at break, it is generally when replacing wires, electrical equipment, etc. that a sample of the wire coating is taken back from the installation site. Therefore, it is difficult to confirm the degree of deterioration of an in-use wire at an arbitrary time.

[0006] The present invention has been completed in view of the above problems of the prior art, and an object thereof is to provide a method for evaluating the degree of deterioration of a wire coating that can be easily carried out even at the installation site without taking back a sample of the wire coating from the installation site.

Means for Solving the Problems

[0007] As a result of intensive studies to achieve the above object, the present inventor has found that by using a specific dye solution, the degree of deterioration of a wire coating containing polyvinyl chloride can be evaluated by a simple method even at the installation site, and has completed the present invention.

[0008] That is, the present invention relates to the following method for evaluating the degree of deterioration of a wire coating. Item 1 A method for evaluating the degree of deterioration of a wire coating containing polyvinyl chloride and a plasticizer, (1) Step 1 of bringing an alcohol solution of a dye into contact with the wire coating to obtain a contact portion, (2) Step 2 of evaluating the degree of deterioration of the wire coating based on the degree of coloring of the contact portion, A method for evaluating the degree of deterioration of a wire coating, comprising the above steps in order. Item 2 The method for evaluating the degree of deterioration of a wire coating according to Item 1 above, wherein the plasticizer is at least one selected from the group consisting of phthalate plasticizers, adipate plasticizers, phosphate plasticizers, and trimellitate plasticizers. Item 3 The method for evaluating the degree of deterioration of a wire coating according to Item 1 or Item 2 above, wherein the dye is at least one selected from the group consisting of azo dyes, anthraquinone dyes, perinone dyes, perylene dyes, methine dyes, and quinoline dyes. Item 4 The alcohol is C 1-4The method for evaluating the degree of deterioration of an electric wire coating according to any one of claims 1 to 3, which is alcohol. Item 5. The method for evaluating the degree of deterioration of an electric wire coating according to any one of claims 1 to 4, wherein the concentration of the dye contained in the alcohol solution is 0.01 to 20% by mass.

Advantages of the Invention

[0009] According to the present invention, the degree of deterioration of the electric wire coating can be easily evaluated at the installation site without destroying the electric wire coating and without bringing back a sample of the electric wire coating from the installation site.

Brief Description of the Drawings

[0010]

Figure 1

Embodiments for Carrying Out the Invention

[0011] Hereinafter, the present invention will be described. In the following, the symbol "~" indicating a numerical range indicates "above and below" unless otherwise specified as meaning "less than" or "exceeding". That is, "A~B" means "A or more and B or less".

[0012] In the present specification, the expression "comprising" or "containing" a certain component includes not only the meaning of including the component and further including other components, but also the concept of "consisting only of" the component alone.

[0013] Method for Evaluating Degradation Degree of Wire Coating The method for evaluating the degree of deterioration of an electric wire coating of the present invention is a method for evaluating the degree of deterioration of an electric wire coating containing polyvinyl chloride and a plasticizer, and includes the following steps 1 and 2; (1) Step 1 of bringing an alcohol solution of a dye into contact with the electric wire coating to obtain a contact portion, (2) Step 2 of evaluating the degree of deterioration of the electric wire coating based on the degree of coloring of the contact portion. are provided in order. Examples of the wire coating include coatings for general electrical workpieces, wiring for electrical equipment, and wiring inside panels, such as polyvinyl chloride insulated wires (e.g., IV wires).

[0014] The polyvinyl chloride is not particularly limited as long as it is polyvinyl chloride used together with a plasticizer as a material for wire coatings.

[0015] The plasticizer is a plasticizer that can be used together with the polyvinyl chloride used for wire coatings, and is not particularly limited as long as the effects of the present invention are exhibited. Specifically, ester-based plasticizers such as phthalic acid ester-based plasticizers, adipic acid ester-based plasticizers, phosphoric acid ester-based plasticizers, and trimellitic acid ester-based plasticizers can be mentioned. Among these, phthalic acid ester-based plasticizers are preferred from the viewpoint that they are highly versatile plasticizers and account for more than half of the plasticizers generally used in polyvinyl chloride wire coating materials, so that most deterioration states can be evaluated. The above plasticizers may be used alone or in combination of two or more.

[0016] The phthalic acid ester-based plasticizer is not particularly limited as long as the effects of the present invention are exhibited. Specifically, phthalic acid ester-based plasticizers such as dibutyl phthalate, dihexyl phthalate, diheptyl phthalate, di-n-octyl phthalate, di-2-ethylhexyl phthalate, diisooctyl phthalate, dinonyl phthalate, diisodecyl phthalate, and dicyclohexyl phthalate can be mentioned. The above phthalic acid ester-based plasticizers may be used alone or in combination of two or more.

[0017] The above adipic acid ester plasticizer is not particularly limited as long as it exhibits the effects of the present invention. Specifically, adipic acid ester plasticizers such as dimethyl adipate, dibutyl adipate, diisodecyl adipate, diisobutyl adipate, diisononyl adipate, di-2-ethylhexyl adipate, di-n-octyl adipate, didecyl adipate, n-octyl-n-decyl adipate, n-heptyl-n-nonyl adipate, benzyl octyl adipate, dibutyl diglycol adipate, etc. can be mentioned. The above adipic acid ester plasticizer may be used alone or in combination of two or more.

[0018] The above phosphate ester plasticizer is not particularly limited as long as it exhibits the effects of the present invention. Specifically, phosphate ester plasticizers such as tributyl phosphate, triphenyl phosphate, tricresyl phosphate, cresyl diphenyl phosphate, etc. can be mentioned. The above phosphate ester plasticizer may be used alone or in combination of two or more.

[0019] The above trimellitic acid ester plasticizer is not particularly limited as long as it exhibits the effects of the present invention. Specifically, trimellitic acid ester plasticizers such as tri-2-ethylhexyl trimellitate (TOTM), tri-n-octyl trimellitate, tridecyl trimellitate, triisodecyl trimellitate, di-n-octyl-n-decyl trimellitate, etc. can be mentioned. Incidentally, the above trimellitic acid ester plasticizer may be used alone or in combination of two or more.

[0020] The content of the plasticizer in the above wire coating is not particularly limited as long as it exhibits the effects of the present invention. Specifically, with respect to 100 parts by mass of polyvinyl chloride, usually, about 2.0 to 20 parts by mass of the plasticizer can be contained.

[0021] As the polyvinyl chloride wire coating material containing the plasticizer described above, it is not particularly limited as long as the effects of the present invention are exhibited. Specifically, polyvinyl chloride wire coating materials such as rigid polyvinyl chloride, flexible vinyl chloride, heat-resistant polyvinyl chloride, and fire-resistant polyvinyl chloride can be mentioned. Among these, in view of the fact that the method for evaluating the degree of deterioration of the wire coating of the present invention mainly evaluates the degree of curing deterioration, the effects of the present invention are particularly easily obtained for flexible polyvinyl chloride.

[0022] Process 1 In step 1, an alcohol solution of a dye is brought into contact with the wire coating to obtain a contact portion. The alcohol in the alcohol solution of the dye is not particularly limited as long as the effects of the present invention are exhibited. Specifically, alcohols having 1 to 4 carbon atoms (also referred to as C 1-4 alcohols) can be mentioned. Such C 1-4 alcohols are not particularly limited as long as the effects of the present invention are exhibited. Specifically, methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutyl alcohol, sec-butyl alcohol, and tert-butyl alcohol can be mentioned. Among these, ethanol is preferable from the viewpoints of safety and ease of use when determining the degree of deterioration in the device installation environment. The above C 1-4 alcohols may be used alone or in combination of two or more.

[0023] The dye is not particularly limited as long as the effects of the present invention are exhibited. Specifically, so-called alcohol dyes or oil-soluble dyes that are soluble in the above alcohol can be used. For example, dyes such as azo dyes, anthraquinone dyes, perinone dyes, perylene dyes, methine dyes, and quinoline dyes can be mentioned. The type of dye can also be selected, for example, from the relationship with the color of the wire coating itself, and a dye whose coloring and degree thereof can be clearly distinguished by contrast with the color of the wire coating itself can be preferably used.

[0024] The concentration of the dye in the above alcohol solution is not particularly limited as long as the effects of the present invention are exhibited. Specifically, in the alcohol solution, it can usually be about 0.01 to 20% by mass. More preferably, it is about 0.1 to 10% by mass, and preferably about 1 to 5% by mass. By setting it at 0.01% by mass or more, the electric wire coating can be sufficiently colored. Also, by setting it at 20% by mass or less, there is an advantage that it becomes easier to compare the degree in the determination of the coloring degree.

[0025] The above alcohol solution may contain esters for the purpose of efficiently dissolving the dye. Such esters are not particularly limited as long as the effects of the present invention are exhibited. Specifically, high-boiling esters and the like can be mentioned.

[0026] The content of the above esters is not particularly limited as long as the effects of the invention are exhibited. Specifically, in the above alcohol solution, the content can usually be about 5 to 50% by mass, and preferably about 25 to 35% by mass.

[0027] The above alcohol solution may contain a surfactant for the purpose of efficiently dispersing the dye. Such a surfactant is not particularly limited as long as the effects of the present invention are exhibited. Specifically, glycol ether-based surfactants and the like can be mentioned. Such glycol ether-based surfactants are not particularly limited as long as the effects of the present invention are exhibited. Specifically, diethylene glycol monobutyl ether, triethylene glycol monobutyl ether, tetraethylene glycol monomethyl ether, propylene glycol monomethyl ether, dipropylene glycol monomethyl ether, tripropylene glycol monomethyl ether, propylene glycol monobutyl ether, etc. can be mentioned. Among them, diethylene glycol monobutyl ether is preferable. High-boiling esters and the like can be mentioned.

[0028] The content of the surfactant is not particularly limited as long as the effects of the invention can be exhibited. Specifically, in the above alcohol solution, it can usually be about 1 to 40% by mass, and preferably about 5 to 15% by mass.

[0029] In addition to the above, the above alcohol solution can contain mineral oil or the like.

[0030] The method of bringing the above alcohol solution into contact with the wire coating to obtain a contact portion is not particularly limited as long as the effects of the present invention can be exhibited. For example, a method of applying it to the wire coating using spraying, dipping, a brush, or the like can be mentioned.

[0031] The contact time of the alcohol solution in Step 1 is not particularly limited as long as the effects of the present invention can be exhibited. Usually, it can be 1 minute to 20 hours. More preferably, it is 6 to 18 hours.

[0032] Process 2 Step 2 evaluates the degree of deterioration of the wire coating based on the degree of coloring of the contact portion. In Step 2, the means for evaluating the degree of coloring only needs to be based on the degree of coloring of the contact portion and is not particularly limited. For example, a means of visually evaluating by the shade of coloring can be mentioned. Therefore, based on the degree of coloring of a wire coating that has not deteriorated, the degree of deterioration of the wire coating can be evaluated. Note that the color tone of the coloring is the color tone exhibited by the dye contained in the alcohol solution used in Step 1. For example, if it is an azo dye, it is generally red.

[0033] In the present invention, it is presumed that the reason why the degree of deterioration of the wire coating can be evaluated by the degree of coloring with an alcoholic solution of a dye is that there is a correlation with the decrease in the content of the plasticizer contained in the wire coating as the degree of deterioration of the wire coating progresses. This also agrees with the conventional knowledge that the elongation at break of the wire coating with advanced deterioration becomes smaller due to the decrease in the content of the plasticizer due to deterioration. Taking a phthalate plasticizer as an example, the plasticizer is divided into a polar part derived from the phthalic acid structure and a nonpolar part derived from the alcohol structure. Since the alcoholic solution of the dye has an affinity for the nonpolar part of the plasticizer, the degree of coloring is large in terms of a large affinity with the alcoholic solution of the dye in a wire coating with little deterioration, and the content of the plasticizer decreases in a wire coating with advanced deterioration. It is presumed that the degree of coloring becomes small in that the affinity with the alcoholic solution of the dye is relatively small.

[0034] Such a degree of deterioration has conventionally been known to be evaluated by the elongation at break. Such an elongation at break and the degree of the above coloring have a correlation, and both can evaluate the degree of deterioration of the wire coating. For example, similar to the evaluation of pH using litmus test paper, the degree of coloring (degree of shade) is used as a standard sample, the elongation at break corresponding thereto is set, and the degree of deterioration of the wire coating can also be quantitatively evaluated from the degree of coloring and the elongation at break.

[0035] In addition, various characteristics such as the properties, structures, functions, etc. described for each embodiment of the present invention described above can be appropriately combined when specifying the embodiments included in the present invention. That is, the present invention can include all inventions of the aspects of each characteristic that can be combined disclosed in this specification.

Example

[0036] Test Example 1 for explaining the present invention in more detail is shown below. Needless to say, the present invention is not limited to Test Example 1 shown below.

[0037] Test Example 1 A test solution was prepared by mixing Color Check (trademark registered) dye penetrant FP-S manufactured by TASSET and ethanol at a ratio of 1:9. The above FP-S contains 1 to 5% by mass of an azo-based oil-soluble dye, 35 to 45% by mass of a high-boiling ester, 40 to 50% by mass of a mineral oil, and 5 to 15% by mass of diethylene glycol monobutyl ether.

[0038] The wire coating used in the test was the IV wire (2Sq) of Fujikura Diamond Cable Co., Ltd. This wire coating was heated at 100°C for a predetermined time (accelerated test). In addition, under the condition described as "bending", the wire coating was subjected to the accelerated test in a bent state. Then, the above test solution was applied to each wire coating after the treatment, and it was left at room temperature for 18 hours.

[0039] After that, the applied treatment solution was removed, and the degree of coloring of the wire coating was observed. In addition, the wire coatings after various treatments were measured for the elongation at break by a tensile property test based on JISC3005 and JISC3316. Photographic images of these wire coatings after coloring and the results of the elongation at break are shown in Fig. 1.

[0040] (1) in Fig. 1 shows the results of the initial product, that is, the untreated wire coating. It was observed that the elongation at break was 222% and it exhibited red color due to the azo-based dye contained in the treatment solution.

[0041] (2) in Fig. 1 shows the results of the wire coating (straight line) subjected to heat treatment for 120 hours. The elongation at break was measured to be 190%, and it was revealed that the degree of coloring was thinner than that of the untreated wire coating in (1) of Fig. 1.

[0042] (3) in Fig. 1 shows the results of the wire coating (straight line) subjected to heat treatment for 240 hours. The elongation at break was measured to be 183%, and it was revealed that the degree of coloring was thinner than that of the untreated wire coating in (1) of Fig. 1.

[0043] (4) in Fig. 1 shows the results of the wire coating (straight line) subjected to heat treatment for 480 hours. The elongation at break was measured to be 111%, and it was revealed that the degree of coloring was thinner than that of the untreated wire coating in (1) of Fig. 1.

[0044] (5) in FIG. 1 is the result of the wire coating (straight line) subjected to the heat treatment for 720 hours. The elongation at break was measured to be 45%, and it was revealed that the degree of coloring became lighter than that of the untreated wire coating in (1) of FIG. 1.

[0045] (6) in FIG. 1 is the result of the wire coating subjected to the bending treatment together with the heat treatment for 120 hours. The elongation at break was measured to be 117%, and it was revealed that the degree of coloring became lighter than that of the untreated wire coating in (1) of FIG. 1.

[0046] (7) in FIG. 1 is the result of the wire coating subjected to the bending treatment together with the heat treatment for 240 hours. The elongation at break was measured to be 91%, and it was revealed that the degree of coloring became lighter than that of the untreated wire coating in (1) of FIG. 1.

[0047] (8) in FIG. 1 is the result of the wire coating subjected to the bending treatment together with the heat treatment for 480 hours. The elongation at break was measured to be 11%, and it was revealed that the degree of coloring became lighter than that of the untreated wire coating in (1) of FIG. 1.

[0048] (9) in FIG. 1 is the result of the wire coating subjected to the bending treatment together with the heat treatment for 720 hours. The elongation at break was measured to be 7%, and it was revealed that the degree of coloring became lighter than that of the untreated wire coating in (1) of FIG. 1.

[0049] From the results of the above tests, it was confirmed that as the elongation at break of the wire coatings subjected to various treatments decreased, the degree of red coloring by the azo-based dye contained in the test solution tended to become lighter. Since the wire coating with an elongation at break of 100% or less reaches the usage limit, it is expected that the wire coating at the usage limit can be confirmed at the installation site by the above test.

[0050] In addition, it has been separately confirmed that the above test solution does not adversely affect the functions of the wires contained in the wire coating.

Claims

1. A method for evaluating the degree of deterioration of an electric wire coating containing polyvinyl chloride and a plasticizer, comprising: (1) Step 1 of obtaining a contact portion by bringing an alcohol solution of a dye into contact with the electric wire coating at the installation site of the electric wire coating; (2) Step 2 of evaluating the degree of deterioration of the electric wire coating based on the degree of coloring of the contact portion. A method for evaluating the degree of deterioration of an electric wire coating, comprising the above steps in sequence.

2. The method for evaluating the degree of deterioration of an electric wire coating according to Claim 1, wherein the plasticizer is at least one selected from the group consisting of phthalate plasticizers, adipate plasticizers, phosphate plasticizers, and trimellitate plasticizers.

3. The method for evaluating the degree of deterioration of an electric wire coating according to Claim 1 or 2, wherein the dye is at least one selected from the group consisting of azo dyes, anthraquinone dyes, perinone dyes, perylene dyes, methine dyes, and quinoline dyes.

4. The alcohol is C １－４ The method for evaluating the degree of deterioration of an electric wire coating according to any one of claims 1 to 3, which is an alcohol.

5. The method for evaluating the degree of deterioration of an electric wire coating according to any one of Claims 1 to 4, wherein the concentration of the dye contained in the alcohol solution is 0.01 to 20% by mass.

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