Resin composition, insulated wire, and method for manufacturing the 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 amount of the first additive group per 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. A fraction value B, obtained by dividing the total amount of the second additive group per 100 pts.mass of the vinyl chloride resin by the total amount of the resin composition, is 6.51 mass% or more and 15 mass% or less. Antimony and bisphenol A are not contained.SELECTED DRAWING: None

Description

Technical Field

[0005] ,

[0004] , , , , ,

[0003]

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

Background Art

[0002] Insulated wires used for internal wiring of electronic devices are required to have flame retardancy in order to prevent the spread of fire along the insulated wire during a fire caused by malfunctions or defects in the electronic devices. For example, the flame retardancy standards for insulated wires are defined by UL758 standards in the United States. Among the items required by the UL758 standard, a vertical combustion test (hereinafter referred to as the "VW-1 test") is provided as an option. However, since most insulated wires pass this "VW-1 test" and are certified under the UL standard, 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 for the coating material of such insulated wires, vinyl chloride resin (PVC) is used. Since 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 vinyl chloride resin is hard, it needs to be softened 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 highly toxic drug, strict management is required in production, 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 perspective of suppressing the increase in the manufacturing cost of insulated wires, it is also a material that we want to avoid using.

[0005] For this reason, metal hydroxides such as aluminum hydroxide and magnesium hydroxide have been used as alternative flame retardants to antimony trioxide.

[0006] For example, Japanese Patent Publication No. 2011-26427 (Patent Document 1) describes a vinyl chloride resin composition comprising vinyl chloride resin, aluminum hydroxide and / or magnesium hydroxide, a plasticizer, and a lead-free 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 per 100 parts by mass of vinyl chloride resin, and the antimony content is less than 1000 ppm.

[0007] Furthermore, trimellitic acid esters are often used as plasticizers in vinyl chloride resin compositions. Some of these trimellitic acid esters have bisphenol A added as an antioxidant. In this regard, in recent years, from the perspective of environmental considerations and environmental laws and regulations, there has been a demand for so-called "bisphenol-free" materials that do not use bisphenol A. [Prior art documents] [Patent Documents]

[0008] [Patent Document 1] Japanese Patent Publication No. 2011-26427 [Overview of the project] [Problems that the invention aims to solve]

[0009] Therefore, for example, resin compositions used in insulated wires are increasingly being made "antimony-free" and "bisphenol-free," meaning they do not contain antimony and bisphenol A. In this regard, the inventors have newly discovered that further efforts to make resin compositions "antimony-free" and "bisphenol-free" reveal the following areas for improvement. (1) Discoloration of resin composition due to the use of a flame retardant instead of antimony (2) The phenomenon of the gel fraction (degree of crosslinking) not improving. (3) Phenomena in which flame retardancy decreases As a result of these phenomena, for example, the "antimony-free" and "non-biscuit" formulations of electron beam-crosslinked resin compositions are not progressing. Therefore, in order to advance the "antimony-free" and "non-biscuit" formulations of electron beam-crosslinked resin compositions, it is desirable to devise ways to overcome the aforementioned areas for improvement.

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

[0011] In one embodiment, the resin composition comprises a vinyl chloride resin, a first group of additives, a second group of additives, and a crosslinking aid, wherein the first group of additives includes titanium dioxide and zinc stearate, and the second group of additives includes aluminum hydroxide, clay, and silica, the gel fraction is 45% by mass or more, the fraction A obtained by dividing the total amount of the first group of additives added per 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 B obtained by dividing the total amount of the second group of additives added per 100 parts by mass of the vinyl chloride resin by the total amount of the resin composition is 6.51% by mass or more and 15% by mass or less, and the resin composition does not contain antimony and bisphenol A.

[0012] In one embodiment, the insulated wire includes a conductor and an insulating layer covering the conductor, and the insulating layer is made of the resin composition described above.

[0013] In one embodiment, the method for producing the resin composition includes a step of crosslinking the above-mentioned resin composition by irradiating it with an electron beam, wherein the product of the amount of crosslinking aid added and the irradiation intensity of the electron beam irradiated during crosslinking is 9 or more. [Effects of the Invention]

[0014] According to one embodiment, a resin composition can be provided that improves environmental performance by not containing antimony and bisphenol A, while suppressing discoloration and improving flame retardancy and gel fraction. [Brief explanation of the drawing]

[0015] [Figure 1] This is a cross-sectional view showing an example of the configuration of an insulated wire. [Modes for carrying out the invention]

[0016] In all the drawings illustrating the embodiments, the same reference numeral is used for identical components, and repeated explanations of them are omitted. Hatching may be used even in plan views to improve clarity.

[0017] <Overview of the technical concept> As a result of diligent consideration, the inventor has come up with a technical idea that can overcome the areas for improvement described in the "Problems to be Solved by the Invention" section. The outline of this technical idea will be explained below.

[0018] The resin composition in this embodiment comprises a vinyl chloride resin, a first group of additives, a second group of additives, and a crosslinking aid. Here, the first group of additives includes titanium dioxide and zinc stearate. The second group of additives includes aluminum hydroxide, clay, and silica. Furthermore, the crosslinking aid is trimethylolpropane triacrylate. Here, the gel fraction is 45% by mass or more. For example, the above-described resin composition with a gel fraction of 45% by mass or more can be realized by the resin composition manufacturing method shown below.

[0019] In other words, the method for producing the resin composition in this embodiment includes a step of crosslinking the above-mentioned resin composition by irradiating it with an electron beam, wherein the product of the amount of crosslinking aid added 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 the use of a flame retardant replacing 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 that can be obtained can be obtained. That is, the technical idea in the present embodiment is to provide a resin composition with a small environmental load by "antimony-free conversion" and "non-bis conversion", while overcoming the room for improvement manifested by "antimony-free conversion" and "non-bis conversion" to improve the performance of the resin composition. It can be said that it is a very excellent technical idea in that respect.

[0021] In particular, the present 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 the present embodiment has the following composition.

[0024] <<Vinyl Chloride Resin>> The resin composition contains polyvinyl chloride resin (PVC) as its main component. In this embodiment, it is desirable that the polyvinyl chloride resin be composed of one or more types of polyvinyl chloride resins having a "K value" of "75.7" or more and "85.6" or less, or two or more types of polyvinyl chloride resins having a "K value" of "71.6" or more and "85.6" or less. This is because, according to findings obtained as a result of diligent research by the inventors, it is difficult to improve the long-term heat resistance after electron beam irradiation with a single polyvinyl 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 by combining it with a polyvinyl chloride resin having a "K value" of "84" or more and "85.6" or less.

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

[0026] Furthermore, from the viewpoint of improving other physical properties of the resin composition, such as flexibility and cold resistance, a "copolymer" obtained by copolymerizing vinyl chloride resin with vinyl acetate or ethylene may be applied.

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

[0028] While not particularly limited, it is preferable to use trimellitate-type plasticizers, such as trimellitate esters, as plasticizers. Examples include tri-2-ethylhexyl trimellitate, tri-normal alkyl trimellitate, triisononyl trimellitate, and isodecyl trimellitate.

[0029] In this embodiment, the antioxidant is, for example, a phenolic antioxidant, which is composed of a substance having three or more hydroxyl groups in one molecule, and the amount added is 0.5% by mass or less of the total amount of plasticizer added. The inventors have found that this plasticizer composition is desirable from the viewpoint of overcoming the aforementioned room for improvement. Furthermore, through further investigation by the inventors, it has been found that a composition in which 20% by mass or less of the total amount of trimellitic acid ester is replaced with chlorinated polyethylene is also desirable from the viewpoint of overcoming the aforementioned room for improvement.

[0030] In this regard, the effectiveness of the plasticizer in this embodiment is verified in the examples described later. Specifically, in the examples, trin-normal alkyl trimellitate (N08A:n-TOTM, manufactured by Kao Corporation) or triisononyl trimellitate (UN302: manufactured by UPC, Taiwan) are evaluated. Here, trin-normal alkyl trimellitate (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, triisononyl trimellitate (UN302: manufactured by UPC, Taiwan) is a plasticizer to which 0.35% by mass of tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyloxymethyl]methane is added.

[0031] Furthermore, as a comparative plasticizer to evaluate the effectiveness of the plasticizer (containing antioxidant) used in this embodiment, a plasticizer (containing 0.5% by mass of Irga 1010) prepared by heating triisononyl trimellitate without antioxidants to 60°C and dissolving 0.5% by mass of tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyloxymethyl]methane will also be evaluated. In addition, trin-normal alkyl trimellitate (N08:n-TOTM, manufactured by Kao Corporation) will also be evaluated as a comparative plasticizer. This trin-normal alkyl trimellitate (N08:n-TOTM, manufactured by Kao Corporation) is a plasticizer to which bisphenol A has been added.

[0032] <<Stabilizer>> The resin composition includes, for example, a stabilizer. Suitable stabilizers include hydrotalcite, stearic acid, metal soap stearate, stearoylbenzoylmethane, dibenzoylmethane, dibenzoylmethane salt, rutile titanium dioxide, trihydroxyethyl isocyanate, phenolic antioxidants, silica, calcium hydroxide, polyethylene oxide, talc, and benzotriazole.

[0033] Here, the amount of hydrotalcite added to the stabilizer is preferably 5 parts by mass or more and less than 15 parts by mass per 100 parts by mass of vinyl chloride resin. This is because if the amount of hydrotalcite added is less than 5 parts by mass, the heat resistance performance will not be exhibited, while if the amount of hydrotalcite added is 15 parts by mass or more, the moldability of the resin composition during kneading and extrusion molding will deteriorate. Furthermore, the fraction value A, obtained by dividing the total amount of zinc stearate and titanium dioxide added per 100 parts by mass of vinyl chloride resin by the total amount of the resin composition, is preferably 1% by mass or more and 2% by mass or less. This is because if the fraction value A is less than 1% by mass, the discoloration suppression effect during electron beam irradiation will not be sufficient, while if the fraction value is greater than 2% by mass, the moldability of the resin composition during kneading and extrusion molding will deteriorate, and material costs will increase.

[0034] <<Titanium Oxide>> In this embodiment, titanium dioxide is used as a masking agent. Examples of titanium dioxide produced include titanium dioxide produced by the "sulfuric acid method," which involves hydrolyzing a titanium sulfate solution to obtain hydrated titanium dioxide and then calcining it, and titanium dioxide produced by the "chlorine method," which involves gas-phase oxidation of titanium halides. Here, for example, the average particle size of the primary particles as measured by electron microscopy is approximately 0.1 μm to 1.0 μm, and the crystal form can be anatase or rutile.

[0035] The titanium dioxide used in this embodiment is a two-layer coated rutile titanium dioxide manufactured by the "chlorine method," and the selected grade is, for example, Chemours' "R103." That is, the titanium dioxide used in this embodiment is covered by a first coating layer covering the titanium dioxide and a second coating layer covering the first coating layer. Here, for example, the first coating layer is made of aluminum oxide, while the second coating layer is made of a polyol. In this case, the polyol includes any of trimethylolmethane, trimethylolethane, trimethylolpropane, or pentaerythritol.

[0036] Here, we will explain the technical significance of using titanium dioxide coated with a first coating layer and a second coating layer. For example, the first coating layer works to activate polymers and plasticizers with titanium dioxide and to suppress quinone color development in the presence of phenolic antioxidants, while the second coating layer exerts a function that further suppresses these effects and also improves dispersibility in the resin composition. In other words, the first coating layer has the function of suppressing quinone color development, and the second coating layer has the function of further suppressing quinone color development and improving dispersibility in the resin composition.

[0037] While there is no problem using titanium dioxide (R820) manufactured by the "sulfuric acid method" and composed only of a first coating layer (e.g., a composite of aluminum, silica, and zinc), the discoloration suppression effect described above cannot be obtained. "R820" is titanium dioxide with an average particle size of 0.26 μm and a titanium content of 93 mass%. In contrast, when titanium dioxide manufactured by the "chlorine method" and coated with a first and second coating layer is used, a remarkable discoloration suppression effect is obtained, as described above. This is the technical significance of using titanium dioxide coated with a first and second coating layer, and it is a new finding discovered by the inventors.

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

[0039] Furthermore, the average particle size of the two-layer coated rutile titanium dioxide is preferably between 0.2 μm and 0.35 μm.

[0040] The aforementioned "R103" is titanium dioxide with a purity of 96% by mass, a coating of 3.2% by mass with aluminum oxide, a coating of 0.2% by mass with polyol, and an average particle size of 0.23 μm.

[0041] <<Filler>> The resin composition includes, for example, a filler. The filler may consist of clay (silicate). In particular, it is desirable that the clay be sintered, fired clay.

[0042] <<Flame retardant>> The resin composition contains a flame retardant. This flame retardant comprises aluminum hydroxide and silica. Here, the fraction B obtained by dividing the total amount of aluminum hydroxide, clay, and silica added per 100 parts by mass of vinyl chloride resin by the total amount of the resin composition is preferably 6% by mass or more and 15% by mass or less. This is because if fraction B is less than 6% by mass, flame retardancy will not be easily achieved, while if fraction B is greater than 15% by mass, it will be difficult to suppress discoloration due to electron beam irradiation.

[0043] <<Crosslinking agent>> The resin composition is crosslinked to improve its properties. In this case, the resin composition contains, for example, a crosslinking aid. Trimethylolpropane triacrylate can be given as an example of a crosslinking aid.

[0044] In this case, increasing the amount of trimethylolpropane triacrylate added can improve the gel fraction (degree of crosslinking). On the other hand, increasing the electron beam irradiation intensity can also improve the gel fraction. However, high electron beam irradiation intensity makes discoloration due to electron beam irradiation more likely. For this reason, from the viewpoint of suppressing discoloration, it is advisable to avoid setting the electron beam irradiation intensity too high. In other words, it is desirable to obtain a high gel fraction even at a low electron beam irradiation intensity. Therefore, in this embodiment, in order to obtain a high gel fraction even at a low electron beam irradiation intensity, the product of the amount of trimethylolpropane triacrylate added per 100 parts by mass of vinyl chloride resin and the electron beam irradiation intensity is applied as an evaluation index for the gel fraction. 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 amount of trimethylolpropane triacrylate added and the electron beam irradiation intensity so that the product of the amount of crosslinking aid added and the irradiation intensity is 9 or more.

[0045] <<Other additives>> The resin composition may contain other additives as needed. Specifically, the resin composition may contain ultraviolet absorbers, light stabilizers, lubricants, colorants, processability improvers, and other modifiers, either individually or in combination of two or more types.

[0046] The resin composition in this embodiment is constructed as described above. Below, an example of the construction of an insulated wire using this resin composition will be described.

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

[0048] As shown in Figure 1, the insulated wire 10 has a conductor 1 and an insulating layer 2 that covers the outer circumference of the conductor 1. In this case, for example, the resin composition described above in this embodiment is used for the insulating layer 2. The insulating layer 2 may be configured to directly cover the conductor 1 as shown in Figure 1, or it can be used as a sheath material that covers the insulated wire 10.

[0049] The insulated wire 10 can be manufactured in this embodiment by coating the conductor 1 with a resin composition using a molding 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] The extrusion coating is performed by extruding the resin composition to cover the wire 1 using a wire extruder equipped with a crosshead die, by kneading the resin composition before crosslinking using a roll, Banbury, extruder, etc., to obtain a pellet compound, and then kneading the wire 1 with the pellet compound.

[0051] As the covered conductor 1, for example, a conductor with an outer diameter of 0.15 mmφ to approximately 7 mmφ can be used. A conductor made by twisting tin-plated soft copper wires can be suitably used as the conductor 1, but it is not limited to these.

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

[0053] In the insulated wire 10 configured in this way, the resin composition described above in this embodiment is used as the resin composition constituting the insulating layer 2. As a result, the insulated wire 10 makes it possible to achieve "antimony-free" and "non-biscuit" resin composition while overcoming the room for improvement that becomes apparent due to "antimony-free" and "non-biscuit" construction. In other words, this embodiment makes it possible to improve the performance of the insulated wire 10 while providing an insulated wire 10 with a low environmental impact. To put it another way, the insulated wire 10 in this embodiment makes it possible to achieve both environmental performance and wire performance.

[0054] The following describes experimental results that support the fact that, by using an insulated wire embodying the technical concept of this embodiment, environmental performance can be improved through "antimony-free" and "non-biscuit" construction, while also improving the performance of the insulated wire itself. However, the technical concept of this embodiment is not limited to the examples shown below.

[0055] <Examples> <<Preparation of Resin Composition>> The resin compositions for Examples 1 to 10, Comparative Examples 1 to 2, and Reference Example 1 were prepared by blending each material in the proportions listed in Table 1 below, then kneading and mixing in an oven roll mixer heated to 170°C to form pellets. The resin compositions for Examples 1 to 10 and Comparative Examples 1 to 2 do not contain antimony and bisphenol A, thus achieving "antimony-free" and "bisphenol-free" properties. On the other hand, the resin composition for Reference Example 1 contains antimony and bisphenol A, and therefore does not achieve "antimony-free" or "bisphenol-free" properties.

[0056] [Table 1]

[0057] <<Manufacturing of insulated wires>> As the conductor, a conductor consisting of 17 strands of tin-plated soft copper wire with an outer diameter of 0.16 mmφ (outer diameter: 0.76 mmφ) was used. After forming a resin composition on this conductor by melt extrusion, an insulated wire (sample) was prepared by coating the conductor with the resin composition. Specifically, multiple samples were prepared in which the conductor was coated with the resin composition for each of Examples 1 to 10, Comparative Examples 1 to 2, and Reference Example 1. 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. Subsequently, the insulated wire was irradiated with an electron beam at a specified irradiation intensity using an electron beam irradiator to induce a crosslinking reaction in the resin composition, thereby producing the final insulated wire.

[0058] <<Evaluation of insulated wires>> The insulated wires that were fabricated were evaluated according to the following criteria.

[0059] (1) Discoloration after electron beam irradiation When mixing the materials in the proportions listed in Table 1 and coloring them with the materials shown in Table 2, insulated wires were prepared and cut to a length of 10 cm. The discoloration before and after electron beam irradiation was evaluated. Here, wires with no visible difference in hue before and after electron beam irradiation were marked with "○", and wires with a difference in hue were marked with "×".

[0060] [Table 2]

[0061] (2) Flame retardant For each of the insulated wires in Examples 1 to 10, Comparative Examples 1 to 2, and Reference Example 1, the "VW-1 test" in accordance with UL758 was performed, and those that passed were marked with "○" and those that failed were marked with "×".

[0062] (3) Gel fraction The insulating layer of the prepared insulated wire was stripped, and the insulating layer was cut into pieces smaller than 1 mm square. The gel was then extracted under tetrahydrofuran at 70°C for 20 hours. The gel fraction was then calculated by drying the extracted gel.

[0063] Samples with a gel fraction of 45% by mass or more were marked with "○", and those with a gel fraction of less than 45% by mass were marked with "×". This is because if the gel fraction is less than 45% by mass, the practical characteristic of the electric wire, "300°C 3sec solder resistance," may not be achieved.

[0064] (4) Evaluation results Table 3 shows the evaluation results for the evaluation items mentioned above.

[0065] [Table 3]

[0066] As shown in Table 3, in Examples 1 to 10, which embody the technical concept of this embodiment, good results were obtained in all evaluation items. On the other hand, in Comparative Examples 1 to 2, to which the technical concept of this embodiment was not applied, all three evaluation items could not be achieved. Specifically, in Comparative Example 1, all three evaluation items failed. In Comparative Example 2, the gel fraction failed. In Reference Example 1, which used a resin composition containing antimony and bisphenol A, good results were obtained in all evaluation items, but "antimony-free" and "bisphenol-free" were not achieved.

[0067] The evaluation results above confirm that the insulated wires (Examples 1 to 10) embodying the technical concept of this embodiment can improve the performance of insulated wires, such as suppressing discoloration, improving flame retardancy, and improving gel fraction, while achieving environmentally friendly "antimony-free" and "non-screw" designs. Therefore, it can be seen that the technical concept of this embodiment is excellent from the standpoint of improving the performance of insulated wires.

[0068] The present invention has been described in detail above based on its embodiments, but it goes without saying that the present invention is not limited to the above embodiments and can be modified in various ways without departing from its essence. [Explanation of symbols]

[0069] 1 conductor 2. Insulating layer 10 Insulated wires

Claims

1. A resin composition comprising a polyvinyl chloride resin, a first group of additives, a second group of additives, and a crosslinking aid, The first group of additives includes titanium dioxide and zinc stearate. The second group of additives includes aluminum hydroxide, clay, and silica. The gel fraction is 45% by mass or more. The fractional value A obtained by dividing the total amount of the first additive group added 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 fractional value B obtained by dividing the total amount of the second additive group added to 100 parts by mass of the vinyl chloride resin by the total amount of the resin composition is 6.51% by mass or more and 15% by mass or less. It does not contain antimony or bisphenol A. The aforementioned resin composition contains a plasticizer including an antioxidant, The aforementioned antioxidant is composed of a substance having a structure in which three or more hydroxyl groups are present in one molecule. The amount of the antioxidant added is 0.5% by mass or less of the total amount of the plasticizer added. The plasticizer is a resin composition comprising trimellitic acid ester and chlorinated polyethylene.

2. In the resin composition according to claim 1, The first group of additives is, Stearoylbenzoylmethane and Trihydroxyethyl isocyanate and, A resin composition containing the following:

3. In the resin composition according to claim 1 or 2, The aforementioned resin composition is a resin composition comprising hydrotalcite.

4. In the resin composition according to claim 3, The hydrotalcite is contained in a resin composition in an amount of 5 parts by mass or more and less than 15 parts by mass per 100 parts by mass of the vinyl chloride resin.

5. In the resin composition according to any one of claims 1 to 4, The aforementioned titanium oxide is The first coating layer covering the titanium oxide, A second coating layer covering the first coating layer, A resin composition covered by a substance.

6. In the resin composition according to claim 5, The first coating layer is composed of aluminum oxide, The second coating layer is a resin composition made of polyol.

7. In the resin composition according to claim 6, The polyol is a resin composition comprising one of the following: trimethylolmethane, trimethylolethane, trimethylolpropane, or pentaerythritol.

8. In the resin composition according to claim 1, The aforementioned antioxidant is a phenolic antioxidant in the resin composition.

9. Wires and, An insulating layer covering the aforementioned conductor, Insulated wires including, The insulating layer is made of the resin composition described in any one of claims 1 to 8, in an insulated wire.

10. It comprises polyvinyl chloride resin, a first group of additives, a second group of additives, and a crosslinking aid. The first group of additives includes titanium dioxide and zinc stearate. The second group of additives includes aluminum hydroxide, clay, and silica. The fractional value A obtained by dividing the total amount of the first additive group added 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 fractional value B obtained by dividing the total amount of the second additive group added to 100 parts by mass of the vinyl chloride resin by the total amount of the resin composition is 6.51% by mass or more and 15% by mass or less. The aforementioned resin composition contains a plasticizer including an antioxidant, The aforementioned antioxidant is composed of a substance having a structure in which three or more hydroxyl groups are present in one molecule. The amount of the antioxidant added is 0.5% by mass or less of the total amount of the plasticizer added. The aforementioned plasticizer comprises trimellitic acid ester and chlorinated polyethylene. A method for producing a resin composition that is free of antimony and bisphenol A and has a gel fraction of 45% by mass or more, The process includes a step of crosslinking the resin composition by irradiating it with an electron beam, The product of the amount of crosslinking aid added and the irradiation intensity of the electron beam is 9 or more. A method for producing a resin composition.

Images