Resin composition, insulated wire, and method for producing resin composition

Abstract

To provide a resin composition which suppresses discoloration while improving environmental performance by not including antimony and bisphenol A, and can improve flame retardancy and a gel fraction.SOLUTION: A resin composition has a vinyl chloride resin, a first additive group, a second additive group, and a crosslinking auxiliary. The first additive group contains titanium oxide, and zinc stearate. The second additive group contains an aluminum hydroxide, a clay and silica. The gel fraction is 45 mass% or more. A fraction value A obtained by dividing the total content of the first additive group with respect to 100 pts.mass of the vinyl chloride resin by the total amount of the resin composition is 1 mass% or more and 2 mass% or less, and a fraction value B obtained by dividing the total additive of the second additive group with respect to 100 pts.mass of the vinyl chloride resin by the total amount of the resin composition is 6 mass% or more and 15 mass% or less.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a resin composition, an insulated wire, and a manufacturing technique of the resin composition. For example, the present invention relates to an insulated wire conforming to UL standards and a resin composition applicable to the insulated wire.

Background Art

[0002] Insulated wires used for internal wiring of electronic devices are required to have flame retardancy so that in the event of a fire caused by a failure or malfunction of the electronic devices, the flame does not spread along the insulated wire. For example, the standard for the flame retardancy of insulated wires is defined by UL758 standard in the United States. Among the items required by the UL758 standard, a vertical combustion test (hereinafter referred to as "VW-1 test") is provided as an option. However, since most insulated wires pass this "VW-1 test" and are certified to UL standards, the "VW-1 test" is an item that is almost an essential item even though it is an optional standard.

[0003] As the main raw material of the coating material for such insulated wires, vinyl chloride resin (PVC) is used. Since the vinyl chloride resin contains chlorine, which is a halogen element, in its chemical structure, the vinyl chloride resin itself has high flame retardancy. However, since the vinyl chloride resin is hard, it is necessary to soften it when used as a coating material for insulated wires. For this reason, a large amount of a flammable plasticizer is added to the vinyl chloride resin. As a result, in insulated wires using vinyl chloride resin, it is impossible to meet the above-mentioned flame retardancy standards without adding a flame retardant.

[0004] Generally, antimony trioxide has been used as a flame retardant. However, since antimony trioxide is a controlled drug, strict management is required in manufacturing, and it is a material that we want to avoid using. Furthermore, antimony is also a rare metal, and its price is on an upward trend. Therefore, from the viewpoint of suppressing an increase in the manufacturing cost of insulated wires, it is also a material that we want to avoid using.

[0005] Therefore, as a flame retardant to replace antimony trioxide, metal hydroxides such as aluminum hydroxide and magnesium hydroxide have been used.

[0006] For example, Japanese Patent Application Laid-Open No. 2011-26427 (Patent Document 1) describes a vinyl chloride resin composition containing a vinyl chloride resin, aluminum hydroxide and / or magnesium hydroxide, a plasticizer, and a non-lead stabilizer, wherein the content of aluminum hydroxide and / or magnesium hydroxide is 8 parts by mass or more and 22 parts by mass or less with respect to 100 parts by mass of the content of the vinyl chloride resin, and the content of antimony is less than 1000 ppm.

[0007] In addition, trimellitic acid ester is often used as a plasticizer in the vinyl chloride resin composition. Some of this trimellitic acid ester have bisphenol A added as an antioxidant. In this regard, in recent years, from the viewpoints of environmental protection and environmental regulations, so-called "non-bisphenol A" that does not use bisphenol A has been demanded.

Prior Art Documents

Patent Documents

[0008]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0009] Therefore, for example, in the resin composition used for insulated electric wires, so-called "antimony-free" and "non-bisphenol A" that do not contain antimony and bisphenol A are being promoted. In this regard, the present inventor has newly found that when promoting "antimony-free" and "non-bisphenol A" of the resin composition, the following room for improvement becomes apparent. (1) Discoloration phenomenon of the resin composition by using a flame retardant to replace antimony (2) The phenomenon that the gel fraction (degree of crosslinking) does not improve (3) The phenomenon that the flame retardancy decreases As a result of such phenomena occurring, for example, there is a current situation where the "antimony-free conversion" and "non-bisphenol conversion" of the resin composition crosslinked by electron beams do not progress. Therefore, in order to promote the "antimony-free conversion" and "non-bisphenol conversion" of the resin composition crosslinked by electron beams, a device to overcome the above-mentioned room for improvement is desired.

[0010] An object of the present invention is to provide a resin composition that can suppress discoloration, improve flame retardancy and gel fraction while improving environmental performance by not containing antimony and bisphenol A.

Means for Solving the Problems

[0011] The resin composition in one embodiment has a vinyl chloride resin, a first additive group, a second additive group, and a crosslinking aid. Here, the first additive group includes titanium oxide and zinc stearate. Also, the second additive group includes aluminum hydroxide, clay, and silica. Here, the gel fraction is 45% by mass or more. And the fraction value A obtained by dividing the total addition amount of the first additive group with respect to 100 parts by mass of the vinyl chloride resin by the total amount of the resin composition is 1% by mass or more and 2% by mass or less, and the fraction value B obtained by dividing the total addition amount of the second additive group with respect to 100 parts by mass of the vinyl chloride resin by the total amount of the resin composition is 6% by mass or more and 15% by mass or less.

[0012] The insulated electric wire in one embodiment includes a conductor and an insulating layer that coats the conductor, and the insulating layer is composed of the above-mentioned resin composition.

[0013] The manufacturing method of the resin composition in one embodiment has a step of crosslinking the above-mentioned resin composition by irradiating with an electron beam, and the product of the addition amount of the crosslinking aid and the irradiation intensity of the electron beam irradiated during crosslinking is 9 or more.

Effects of the Invention

[0014] According to one embodiment, it is possible to provide a resin composition that can improve environmental performance by not containing antimony and bisphenol A, suppress discoloration, and improve flame retardancy and gel fraction.

Brief Description of the Drawings

[0015]

Figure 1

Embodiments for Carrying Out the Invention

[0016] In all the drawings for explaining the embodiments, the same members are basically given the same reference numerals, and the repeated explanations thereof are omitted. Note that, in order to make the drawings easy to understand, hatching may be added even in a plan view.

[0017] <Summary of the Technical Idea> As a result of intensive studies, the inventor has come up with a technical idea that can overcome the room for improvement described in the column of "Problems to be Solved by the Invention". Therefore, the following is an explanation of the summary of this technical idea.

[0018] The resin composition in this embodiment has a vinyl chloride resin, a first additive group, a second additive group, and a crosslinking aid. Here, the first additive group includes titanium oxide and zinc stearate. The second additive group includes aluminum hydroxide, clay, and silica. Further, the crosslinking aid is trimethylolpropane triacrylate. Here, the gel fraction is 45% by mass or more. For example, the above-described resin composition having a gel fraction of 45% by mass or more can be realized by the following method for producing a resin composition.

[0019] That is, the method for producing a resin composition in this embodiment has a step of crosslinking the above-described resin composition by irradiating with an electron beam, and the product of the addition amount of the crosslinking aid and the irradiation intensity of the electron beam irradiated during crosslinking is 9 or more.

[0020] According to the resin composition configured as described above, even if the "antimony-free conversion" and "non-bis conversion" of the resin composition are advanced, the room for improvement manifested by the "antimony-free conversion" and "non-bis conversion" {(1) the discoloration phenomenon of the resin composition due to using a flame retardant instead of antimony, (2) the phenomenon that the gel fraction (crosslinking degree) does not improve, (3) the phenomenon that the flame retardancy decreases} can be overcome, and a remarkable effect can be obtained. That is, the technical idea in this embodiment is that while providing a resin composition with a small environmental load by "antimony-free conversion" and "non-bis conversion", it is possible to overcome the room for improvement manifested by "antimony-free conversion" and "non-bis conversion" and improve the performance of the resin composition, which is an extremely excellent technical idea.

[0021] In particular, the inventor further examined in detail based on the above-described technical idea, and as a result, newly found a configuration of a resin composition desirable for achieving the above-described remarkable effect. Therefore, a new configuration example of this resin composition will be described.

[0022] <Configuration of Resin Composition> A configuration example of a resin composition embodying the above-described technical idea will be described.

[0023] The resin composition in this embodiment has the following composition.

[0024] <<Vinyl Chloride Resin>> The resin composition contains vinyl chloride resin (PVC) as the main component. Here, the vinyl chloride resin in the present embodiment is composed of, for example, one or more vinyl chloride resins with a "K value" of 75.7 or more and 85.6 or less, or desirably composed of two or more vinyl chloride resins with a "K value" of 71.6 or more and 85.6 or less. This is because, according to the findings obtained from the intensive studies by the present inventor, it is difficult to improve the long-term heat resistance after electron beam irradiation with a single vinyl chloride resin having a "K value" of 71.6, while it has been found that the long-term heat resistance after electron beam irradiation can be improved when combining vinyl chloride resins with a "K value" of 84 or more and 85.6 or less.

[0025] In the present embodiment, as one or more vinyl chloride resins with a "K value" of 75.7 or more and 85.6 or less, a vinyl chloride resin commonly known as "degree of polymerization P = 1700" with a "K value" in the range of 75.7 or more and 78.1 or less is used. Here, the "K value" is not the degree of polymerization itself but an index in a proportional relationship with the degree of polymerization.

[0026] In addition, from the viewpoint of improving other physical properties typified by the flexibility and cold resistance of the resin composition, a "copolymer" in which vinyl acetate or ethylene is copolymerized with the vinyl chloride resin may be applied.

[0027] <<Plasticizer>> The resin composition contains, for example, a plasticizer containing an antioxidant.

[0028] Although not particularly limited, it is desirable to use a trimellitate-based plasticizer typified by trimellitic acid ester as the plasticizer. For example, tri-2-ethylhexyl trimellitate, trinormal alkyl trimellitate, triisononyl trimellitate, and isodecyl trimellitate can be mentioned.

[0029] In this embodiment, the antioxidant is, for example, a phenolic antioxidant, and this phenolic antioxidant is composed of a substance having three or more hydroxy groups in one molecule, and its addition amount is 0.5% by mass or less of the total addition amount of the plasticizer. According to the study by the present inventor, such a composition of the plasticizer has been newly found to be a desirable composition from the viewpoint of overcoming the above-described room for improvement. And, according to further study by the present inventor, it has been found that even in a composition in which 20% by mass or less of the total addition amount of trimellitic acid ester is replaced with chlorinated polyethylene, it is desirable from the viewpoint of overcoming the above-described room for improvement.

[0030] Regarding this point, in the examples described later, the effectiveness of the plasticizer in this embodiment is verified. Specifically, in the examples, trimellitic acid trinormal alkyl (N08A: n-TOTM manufactured by Kao Corporation) or trimellitic acid triisononyl (UN302: manufactured by Taiwan UPC) is evaluated. Here, trimellitic acid trinormal alkyl (N08A: n-TOTM manufactured by Kao Corporation) is a plasticizer to which 0.3% by mass of tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyloxymethyl]methane is added. On the other hand, trimellitic acid triisononyl (UN302: manufactured by Taiwan UPC) is a plasticizer to which 0.35% by mass of tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyloxymethyl]methane is added.

[0031] In addition, as a comparative plasticizer for evaluating the effectiveness of the plasticizer (containing an antioxidant) used in this embodiment, trisisononyl trimellitate without added antioxidant was heated to 60°C, and a plasticizer (product with 0.5% by mass of Irganox 1010 added) in which 0.5% by mass of pentaerythrityl tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] was dissolved was also evaluated. Furthermore, as a comparative plasticizer, trisnormalalkyl trimellitate (N08: n-TOTM, manufactured by Kao Corporation) was also evaluated. This trisnormalalkyl trimellitate (N08: n-TOTM, manufactured by Kao Corporation) is a plasticizer to which bisphenol A is added.

[0032] <<Stabilizer>> The resin composition contains, for example, a stabilizer. As the stabilizer, hydrotalcite, stearic acid, metal stearate, stearoyl benzoyl methane, dibenzoyl methane, dibenzoyl methane salt, rutile-type titanium oxide, trihydroxyethyl isocyanate, phenolic antioxidant, silica, calcium hydroxide, polyethylene oxide, talc, benzotriazole, etc. can be used.

[0033] Here, the addition amount of hydrotalcite contained in the stabilizer is desirably 5 parts by mass or more and less than 15 parts by mass with respect to 100 parts by mass of the vinyl chloride resin. This is because when the addition amount of hydrotalcite is less than 5 parts by mass, the heat resistance performance is not exhibited, while when the addition amount of hydrotalcite is 15 parts by mass or more, the molding processability during kneading or extrusion molding of the resin composition deteriorates. Furthermore, the fraction value A obtained by dividing the total addition amount of zinc stearate and titanium oxide by the total amount of the resin composition with respect to 100 parts by mass of the vinyl chloride resin is desirably 1% by mass or more and 2% by mass or less. This is because when the fraction value A is less than 1% by mass, the discoloration suppression effect during electron beam irradiation is not sufficient, while when the fraction value is greater than 2% by mass, the molding processability during kneading or extrusion molding of the resin composition deteriorates and the material cost increases.

[0034] <<Titanium Oxide>> The titanium oxide in this embodiment is used as a masking agent. Examples of this titanium oxide include titanium oxide produced by the "sulfuric acid method" in which hydrous titanium oxide obtained by hydrolyzing a titanium sulfate solution is calcined, and the "chlorine method" in which titanium halide is vapor-phase oxidized. Here, for example, the average particle diameter of the primary particles by electron micrography is about 0.1 μm or more and 1.0 μm or less, and the crystal form can include anatase type and rutile type.

[0035] The titanium oxide used in this embodiment is a two-layer coated rutile type titanium oxide produced by the "chlorine method". For example, the selected grade is "R103" of Kemira. That is, the titanium oxide used in this embodiment is covered by a first coating layer covering the titanium oxide and a second coating layer covering the first coating layer. Here, for example, the first coating layer is composed of aluminum oxide, while the second coating layer is composed of polyol. At this time, the polyol contains any one of trimethylolmethane, trimethylolethane, trimethylolpropane, and pentaerythritol.

[0036] Here, the technical significance of using titanium oxide coated with the first coating layer and the second coating layer will be described. For example, the first coating layer functions to activate polymers and plasticizers by titanium oxide and to suppress quinone coloring in the presence of phenolic antioxidants, and the second coating layer functions to further suppress them and to improve the dispersibility in the resin composition. That is, the first coating layer has a function of suppressing quinone coloring, and the second coating layer has a function of further suppressing quinone coloring and a function of improving the dispersibility in the resin composition.

[0037] There is no problem even if titanium oxide (R820) manufactured by the "sulfuric acid method" and composed only of the first coating layer (for example, a composite of aluminum, silica, and zinc) is applied, but the discoloration suppression effect as described above cannot be obtained. "R820" is titanium oxide with an average particle diameter of 0.26 μm and a titanium content of 93% by mass. On the other hand, when titanium oxide manufactured by the "chlorine method" and coated with the first coating layer and the second coating layer is used, as described above, a remarkable discoloration suppression effect can be obtained. This point is the technical significance of using titanium oxide coated with the first coating layer and the second coating layer, and is a newly discovered finding by the present inventor.

[0038] In the two-layer coated rutile-type titanium oxide represented by "R103", the concentration of titanium oxide is desirably 90% by mass or more, and further desirably 95% by mass or more from the viewpoint of suppressing discoloration due to electron beam irradiation caused by impurities. The coating amount of aluminum oxide constituting the first coating layer is desirably 1.7% by mass or more and 4.3% by mass or less, and the coating amount of polyol constituting the second coating layer is desirably 0.15% by mass or more and 0.3% by mass or less.

[0039] Also, the average particle diameter of the two-layer coated rutile-type titanium oxide is desirably 0.2 μm or more and 0.35 μm or less.

[0040] Incidentally, the above-mentioned "R103" is titanium oxide with a purity of 96% by mass, a coating amount of 3.2% by mass with aluminum oxide, a coating amount of 0.2% by mass with polyol, and an average particle diameter of 0.23 μm.

[0041] <<Filler>> The resin composition contains, for example, a filler. The filler can be composed of clay (silicate). In particular, the clay is preferably sintered fired clay.

[0042] <<Flame Retardant>> The resin composition contains a flame retardant. This flame retardant has aluminum hydroxide and silica. Here, with respect to 100 parts by mass of the vinyl chloride resin, it is desirable that the fraction value B obtained by dividing the total addition amount of aluminum hydroxide, clay, and silica by the total amount of the resin composition is 6% by mass or more and 15% by mass or less. This is because when the fraction value B is less than 6% by mass, it becomes difficult to exhibit flame retardancy, while when the fraction value B is greater than 15% by mass, it becomes difficult to suppress discoloration due to electron beam irradiation.

[0043] <<Crosslinking aid>> The resin composition is crosslinked from the viewpoint of improving characteristics. In this case, the resin composition contains, for example, a crosslinking aid. Examples of the crosslinking aid include trimethylolpropane triacrylate.

[0044] Here, increasing the addition amount of trimethylolpropane triacrylate can improve the gel fraction (crosslinking degree). On the other hand, the gel fraction can also be improved by increasing the irradiation intensity of the electron beam. However, when the irradiation intensity of the electron beam is high, discoloration due to electron beam irradiation is likely to occur. From this perspective of suppressing coloring, it is necessary to avoid increasing the irradiation intensity of the electron beam too much. That is, it is desirable to obtain a high gel fraction even when the irradiation intensity of the electron beam is low. Therefore, in this embodiment, for the purpose of obtaining a high gel fraction even when the irradiation intensity of the electron beam is low, as an evaluation index for the gel fraction, the product of the addition amount of trimethylolpropane triacrylate with respect to 100 parts by mass of the vinyl chloride resin and the irradiation intensity of the electron beam is applied. At this time, from the viewpoint of obtaining a high gel fraction (gel fraction of 45% by mass or more), it is desirable to adjust the addition amount of trimethylolpropane triacrylate and the irradiation intensity of the electron beam so that the product of the addition amount of the crosslinking aid and the irradiation intensity is 9 or more.

[0045] <<Other additive materials>> Other additive materials may be added to the resin composition as necessary. Specifically, an ultraviolet absorber, a light stabilizer, a lubricant, a colorant, a processability improver, or other modifiers may be added to the resin composition alone or in combination of two or more kinds.

[0046] As described above, the resin composition in this embodiment is configured. Hereinafter, a configuration example of an insulated wire using this resin composition will be described.

[0047] <Configuration of Insulated Wire> FIG. 1 is a cross-sectional view showing a configuration example of an insulated wire.

[0048] As shown in FIG. 1, the insulated wire 10 has a conductor 1 and an insulating layer 2 that covers the outer periphery of the conductor 1. At this time, for example, the resin composition in the above-described embodiment is used for the insulating layer 2. As shown in FIG. 1, the insulating layer 2 may be configured to directly cover the conductor 1, or can also be used as a sheath material that covers the insulated wire 10.

[0049] The insulated wire 10 can be manufactured in this embodiment by covering the conductor 1 with the resin composition by forming means such as extrusion coating and then crosslinking the resin composition constituting the insulating layer 2 by a method such as electron beam irradiation.

[0050] Note that the extrusion coating is performed by extruding the resin composition to cover the conductor with an wire extruder equipped with a crosshead die using a pellet compound obtained by kneading the resin composition before crosslinking using a roll, a Banbury mixer, an extruder, etc. and the conductor 1.

[0051] As the conductor 1 to be covered, for example, a conductor having an outer diameter of 0.15 mmφ or more and about 7 mmφ can be used. As the conductor 1, a conductor obtained by twisting tinned soft copper wires can be preferably used, but is not limited thereto.

[0052] In addition, the outer diameter of the insulated wire 10 is, for example, about 0.4 mmφ or more and 11 mmφ or less, and its applications include wiring in high-temperature parts inside devices such as dryers, rice cookers, transformer outlets, lighting fixtures, and air conditioners.

[0053] According to the insulated wire 10 configured as described above, the resin composition constituting the insulating layer 2 is the resin composition in the above-described embodiment. From this, according to the insulated wire 10, while realizing "antimony-free" and "non-bisphenol A", it is possible to overcome the room for improvement manifested by "antimony-free" and "non-bisphenol A". That is, according to the present embodiment, it is possible to improve the performance of the insulated wire 10 while providing the insulated wire 10 with a small environmental load. In other words, according to the insulated wire 10 in the present embodiment, it is possible to achieve both environmental performance and wire performance.

[0054] Hereinafter, experimental results will be described to prove that according to the insulated wire embodying the technical idea in the present embodiment, while improving the environmental performance by "antimony-free" and "non-bisphenol A", the wire performance of the insulated wire itself can also be improved. However, the technical idea in the present embodiment is not limited to the examples shown below.

[0055] <Example> <<Preparation of Resin Composition>> After blending each material at the ratios described in Table 1 below and then kneading and mixing with an oven roll mixer heated to 170°C and pelletizing, the resin compositions in each of Examples 1 to 10, Comparative Examples 1 to 2, and Reference Example 1 were prepared. The resin compositions in each of Examples 1 to 10 and Comparative Examples 1 to 2 do not contain antimony and bisphenol A, and "antimony-free" and "non-bisphenol A" are realized. On the other hand, the resin composition in Reference Example 1 is a resin composition containing antimony and bisphenol A, and "antimony-free" and "non-bisphenol A" are not realized.

[0056]

Table 1

[0057] <<Manufacture of Insulated Wire>> As the conductor, a conductor (outer diameter: 0.76 mmφ) obtained by twisting 17 tin-plated soft copper wires with an outer diameter of 0.16 mmφ was used. After forming a resin composition on this conductor by the melt extrusion method, an insulated wire (sample) in which the conductor was coated with the resin composition was manufactured. Specifically, a plurality of samples in which the conductor was coated with the resin composition in each of Examples 1 to 10, Comparative Examples 1 to 2, and Reference Example 1 were manufactured. The thickness of the insulating layer made of the resin composition was 0.5 mm. The wire manufacturing conditions were a cylinder temperature of 170°C, a head temperature of 180°C, and a wire speed of 20 m / min. Then, by irradiating the insulated wire with an electron beam at a specified irradiation intensity using an electron beam irradiator, a crosslinking reaction was caused in the resin composition to produce the final insulated wire.

[0058] <<Evaluation of Insulated Wire>> The manufactured insulated wire was evaluated for the following items.

[0059] (1) Discoloration after Electron Beam Irradiation When kneading each material by blending at the ratio described in Table 1 and coloring with the materials shown in Table 2, the insulated wire thus produced was cut into a length of 10 cm, and the discoloration before and after electron beam irradiation was evaluated. Here, those with no difference in hue before and after electron beam irradiation visually were marked as "〇", and those with a difference in hue were marked as "×".

[0060]

Table 2

[0061] (2) Flame Retardancy For the insulated wires in each of Examples 1 to 10, Comparative Examples 1 to 2, and Reference Example 1, the "VW-1 test" compliant with UL758 was carried out, and those passing were marked as "〇", and those failing were marked as "×".

[0062] (3) Gel fraction The insulating layer of the prepared insulated wire was peeled off and cut into pieces of 1 mm or less square, after which a gel was extracted under tetrahydrofuran at 70° C. for 20 hours, and the extracted gel was then dried to calculate the gel fraction.

[0063] Those with a gel fraction of 45% by mass or more were rated as "Good," and those with a gel fraction of less than 45% by mass were rated as "Poor." If the gel fraction is less than 45% by mass, there is a possibility that the practical characteristic of the electric wire, "300°C 3-second solder resistance," may not be obtained.

[0064] (4) Evaluation results The evaluation results for the above-mentioned evaluation items are shown in Table 3.

[0065] [Table 3]

[0066] As shown in Table 3, in Examples 1 to 10 in which the technical idea of ​​the present embodiment is embodied, good results were obtained in all evaluation items. On the other hand, in Comparative Examples 1 and 2 in which the technical idea of ​​the present embodiment is not applied, it was not possible to achieve all three evaluation items. That is, Comparative Example 1 failed all three evaluation items. Moreover, Comparative Example 2 failed the gel fraction. Note that, in Reference Example 1 in which a resin composition containing antimony and bisphenol A was used, good results were obtained in all evaluation items, but "antimony-free" and "non-bisphenol A" were not achieved.

[0067] From the above evaluation results, according to the insulated electric wires (Examples 1 to 10) in which the technical idea in the present embodiment is embodied, while realizing "antimony-free" and "non-bis" which are environmentally friendly, it is proved that the performance of the insulated electric wire can be improved, which is represented by suppression of discoloration, improvement of flame retardancy, and improvement of gel fraction. Therefore, it can be understood that the technical idea in the present embodiment is very excellent from the viewpoint of improving the performance of the insulated electric wire.

[0068] As described above, the invention made by the present inventor has been specifically described based on the embodiments. However, it goes without saying that the present invention is not limited to the above embodiments and can be variously modified without departing from the gist thereof.

Explanation of Reference Numerals

[0069] 1 Conductor 2 Insulation layer 10 Insulated electric wire

Claims

1. A resin composition comprising a vinyl chloride resin, a first additive group, a second additive group, and a crosslinking aid, wherein the first additive group includes titanium oxide and zinc stearate, the second additive group includes aluminum hydroxide, clay, and silica, the gel fraction is 45% by mass or more, the fraction value A obtained by dividing the total addition amount of the first additive group with respect to 100 parts by mass of the vinyl chloride resin by the total amount of the resin composition is 1% by mass or more and 2% by mass or less, the fraction value B obtained by dividing the total addition amount of the second additive group with respect to 100 parts by mass of the vinyl chloride resin by the total amount of the resin composition is 6% by mass or more and 15% by mass or less, the titanium oxide is covered by a first coating layer covering the titanium oxide, and a second coating layer covering the first coating layer, the first coating layer is composed of aluminum oxide, and the second coating layer is composed of a polyol. A resin composition.

2. In the resin composition according to Claim 1, the first additive group includes stearoyl benzoyl methane, and trihydroxyethyl isocyanate. A resin composition.

3. In the resin composition according to Claim 1 or 2, the resin composition includes hydrotalcite. A resin composition.

4. In the resin composition according to Claim 3, the hydrotalcite is contained in an amount of 5 parts by mass or more and less than 15 parts by mass with respect to 100 parts by mass of the vinyl chloride resin. A resin composition.

5. In the resin composition according to Claim 1, the polyol includes any one of trimethylol methane, trimethylol ethane, trimethylol propane, and pentaerythritol. A resin composition.

6. In the resin composition according to any one of Claims 1 to 5, the resin composition has a plasticizer containing an antioxidant, the antioxidant is composed of a substance having three or more hydroxy groups in one molecule, and the addition amount of the antioxidant is 0.5% by mass or less of the total addition amount of the plasticizer. A resin composition.

7. In the resin composition according to Claim 6, the plasticizer includes a trimellitic acid ester, and the antioxidant is a phenolic antioxidant. A resin composition.

8. In the resin composition according to Claim 6, the plasticizer includes a trimellitic acid ester, and chlorinated polyethylene. A resin composition.

9. ​ ​ ​ ​ In the resin composition according to any one of claims 1 to 8, A resin composition that does not contain antimony and bisphenol A.

10. A conductive wire, An insulating layer covering the conductive wire, An insulated electric wire comprising: The insulating layer is an insulated electric wire composed of the resin composition according to any one of claims 1 to 9.

11. A method for producing a resin composition having a vinyl chloride resin, a first additive group, a second additive group, and a crosslinking aid, The first additive group includes titanium oxide and zinc stearate, The second additive group includes aluminum hydroxide, clay, and silica, The titanium oxide is A first coating layer covering the titanium oxide, A second coating layer covering the first coating layer, Covered by The first coating layer is composed of aluminum oxide, The second coating layer is composed of polyol, The fraction value A obtained by dividing the total addition amount of the first additive group with respect to 100 parts by mass of the vinyl chloride resin by the total amount of the resin composition is 1% by mass or more and 2% by mass or less, The fraction value B obtained by dividing the total addition amount of the second additive group with respect to 100 parts by mass of the vinyl chloride resin by the total amount of the resin composition is 6% by mass or more and 15% by mass or less, Having a step of crosslinking the resin composition by irradiating with an electron beam, A method for producing a resin composition, wherein the product of the addition amount of the crosslinking aid and the irradiation intensity of the electron beam is 9 or more.

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