Vinyl chloride resin composition, electric wire, and cable

Abstract

To provide a vinyl chloride resin composition which does not impair flexibility and cold resistance while imparting abrasion resistance, and to provide an electric wire and a cable.SOLUTION: A vinyl chloride resin composition comprising: a vinyl chloride resin; a trimellitate; surface-treated calcium carbonate; antimony oxide; clay; and a silicone lubricant to which an acrylic group is grafted, wherein an amount of the silicone lubricant is greater than or equal to 0.5 parts by mass and less than or equal to 5 parts by mass with respect to 100 parts by mass of the vinyl chloride resin.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a vinyl chloride resin composition, an electric wire, and a cable. [Background technology]

[0002] Vinyl chloride resin is inexpensive and produced in large quantities, and its physical properties can be controlled over a wide range, from hard to soft, by adjusting the degree of polymerization of the monomer vinyl chloride (chloroethylene) and the amount of plasticizer used. For this reason, vinyl chloride resin is widely used as an industrial resin material in plumbing and pipe components, construction materials, automotive components, adhesives, various films, wallpaper and leather surface materials, tubes, and electrical wire and cable coatings.

[0003] In the field of wire and cable coating, PVC resin has long been used in a wide range of applications as a base material for insulators and sheaths (outer layers), taking advantage of its many advantages, including not only economic efficiency but also high electrical insulation, flame retardancy, chemical resistance, water resistance, and colorability.

[0004] For example, Patent Document 1 (JP 2024-14586 A) discloses a vinyl chloride resin composition containing 5 parts by mass or more and less than 30 parts by mass of a polyester plasticizer relative to 100 parts by mass of vinyl chloride resin. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2024-14586 Summary of the Invention [Problem to be solved by the invention]

[0006] In recent years, for example, in industrial robot applications, there is a need to run multiple wires in a smaller space due to the miniaturization of robots and the expansion of communication data volumes. To meet this demand, it is necessary to make electric wires and cables thinner. An effective way to make electric wires and cables thinner is to use thinner insulation materials. However, even if the insulation material is made thinner, it is often required to maintain the same standard characteristics as before. In particular, because the thickness of the insulation material has a significant effect on abrasion resistance, thinner insulation requires that the abrasion resistance be improved compared to before.

[0007] The present invention has been made in view of the above, and an object of the present invention is to provide a vinyl chloride resin composition, an electric wire, and a cable that impart abrasion resistance without impairing flexibility or cold resistance.

[0008] Other objects and novel features will become apparent from the description of this specification and the accompanying drawings. [Means for solving the problem]

[0009] A vinyl chloride resin composition according to one embodiment of the present invention comprises a vinyl chloride resin, a trimellitic acid ester, surface-treated calcium carbonate, antimony oxide, clay, and an acrylic group-grafted silicone lubricant, the content of the silicone lubricant being 0.5 parts by mass or more and 5 parts by mass or less per 100 parts by mass of the vinyl chloride resin. [Effects of the Invention]

[0010] One aspect of the present invention can provide a vinyl chloride resin composition, an electric wire, and a cable that are imparted with abrasion resistance without impairing flexibility or cold resistance. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a cross-sectional schematic diagram of an electric wire and a cable. [Figure 2] FIG. 2 is a schematic diagram of the wire manufacturing (extrusion) process. DETAILED DESCRIPTION OF THE INVENTION

[0012] The present inventors conducted extensive research into imparting abrasion resistance to vinyl chloride resin compositions and found that reducing the amount of plasticizer is effective. Plasticizers have the effect of electrically attracting vinyl chloride molecules, thereby weakening the attractive forces between vinyl chloride molecules and increasing flexibility. In other words, reducing the amount of plasticizer reduces the effect of weakening the attractive forces between vinyl chloride molecules, hardening the vinyl chloride resin composition and improving abrasion resistance. However, trade-offs for imparting abrasion resistance include reduced flexibility and reduced cold resistance due to reduced mobility of vinyl chloride molecules.

[0013] Therefore, the inventors of the present invention investigated ways to absorb stress applied during abrasion without changing the hardness of the composition by increasing the lubricity of the composition, rather than by hardening the composition to impart abrasion resistance. Furthermore, in order to absorb stress applied during abrasion, they investigated adding a silicone-based lubricant with high lubricity that absorbs stress to the vinyl chloride resin composition.

[0014] As a result of their investigations, they found that lubricants simply having a silicone backbone are not sufficiently compatible with vinyl chloride resin compositions and may precipitate on the surface of the composition during use of electric wires and cables. They also found that the lubricant precipitated on the surface of the composition may gradually disappear due to friction between electric wires and cables, resulting in a decrease in the lubricating effect. Therefore, they investigated the use of a compound in which an acrylic group is grafted onto a silicone backbone as a lubricant that also has a polar group in addition to a silicone backbone to enhance compatibility with vinyl chloride resin compositions. As a result, they found that using a compound in which an acrylic group is grafted onto a silicone backbone is particularly effective in improving the abrasion resistance of electric wire and cable coating materials.

[0015] Hereinafter, the embodiments will be described in detail with reference to the drawings. In all the drawings for explaining the embodiments, the same reference numerals are used to designate components having the same functions, and repeated explanations thereof will be omitted. In the following embodiments, the explanations of the same or similar parts will not be repeated unless particularly necessary.

[0016] <<Vinyl chloride resin composition>> A vinyl chloride resin composition according to one embodiment will be described. The vinyl chloride resin composition according to this embodiment contains a vinyl chloride resin, a trimellitic acid ester, calcium carbonate, antimony oxide, clay, and a silicone lubricant.

[0017] The vinyl chloride resin composition of the present embodiment can be used for covering electric wires or cables.

[0018] <Vinyl chloride resin> Vinyl chloride resin is a polymer formed by the polymerization of the monomer vinyl chloride (chloroethylene). The physical properties of vinyl chloride resin products can be controlled over a wide range, from hard to soft, by adjusting the degree of polymerization of the vinyl chloride monomer, the type of plasticizer, and the amount of plasticizer added. In this embodiment, the number-average degree of polymerization of the vinyl chloride resin is preferably 800 or more and 3000 or less. If the number-average degree of polymerization of the vinyl chloride resin is too low, the material viscosity may decrease. This may result in reduced processability, such as reduced dispersibility of additives and increased stickiness to the equipment. As a result, the manufacturing operations of electric wires and cables may become difficult. The number-average degree of polymerization of the vinyl chloride resin is more preferably approximately 1300. By adjusting the number-average degree of polymerization of the vinyl chloride resin to approximately 1300, it is possible to perform kneading and coating molding operations without any problems. The number-average degree of polymerization is calculated using the method specified in JIS K6720-2. <Trimellitic acid ester> In this embodiment, trimellitic acid ester is added as a plasticizer. By using trimellitic acid ester, the use of phthalic acid esters, which are environmentally hazardous, can be avoided. Furthermore, electrical insulation properties and heat aging resistance can be improved. As a result, the vinyl chloride resin composition can be easily used as a wire coating material. The plasticizer is a component that imparts flexibility to the vinyl chloride resin composition and makes it easier to process.

[0019] The trimellitic acid ester in this embodiment is not particularly limited and is at least one selected from the group consisting of trimellitic acid tris-2-ethylhexyl ester (TOTM), trimellitic acid isononyl ester, and trimellitic acid mixed linear alkyl esters. Trimellitic acid tris-2-ethylhexyl ester is preferably used as the plasticizer because of its high plasticization efficiency, the fact that it can avoid the use of phthalate esters, and its excellent economical efficiency. The content of the trimellitic acid ester is preferably 45 parts by mass or more and 80 parts by mass or less per 100 parts by mass of the vinyl chloride resin.

[0020] <Surface-treated calcium carbonate> In this embodiment, calcium carbonate is added as a stabilizer. By adding calcium carbonate to vinyl chloride resin, it is possible to efficiently capture hydrogen chloride gas generated during combustion of vinyl chloride resin. Furthermore, by adding surface-treated calcium carbonate, it is possible to more efficiently capture hydrogen chloride gas generated during combustion. In other words, calcium carbonate can function as a hydrogen chloride scavenger. The calcium carbonate is preferably fine particle calcium carbonate. The particle diameter of calcium carbonate is preferably 0.5 μm or more and 1.5 μm or less, and more preferably 1.0 μm or less. This makes it possible to more efficiently capture hydrogen chloride gas generated during combustion of vinyl chloride resin. Here, the particle diameter is the average particle diameter calculated using the following formula from the specific surface area determined by air permeability analysis (the density of calcium carbonate is 2.71 g / cm 3 ). Average particle diameter [μm] = 6 / (specific surface area [m2 / g]×density[g / cm 3 ])

[0021] However, as calcium carbonate particles become smaller, their specific surface area increases, which may lead to greater agglomeration between the calcium carbonate particles. The agglomerated calcium carbonate particles may reduce the efficiency of capturing hydrogen chloride gas generated during combustion and may reduce the oil resistance of a vinyl chloride resin composition containing the agglomerated calcium carbonate particles. Therefore, the calcium carbonate particles used in this embodiment are preferably surface-treated with a surface treatment agent. This can prevent the calcium carbonate particles from agglomerating together.

[0022] The surface treatment agent is preferably a fatty acid. This further suppresses aggregation between particles. Examples of fatty acids include, but are not limited to, medium-chain saturated fatty acids having 6 to 12 carbon atoms, medium-chain unsaturated fatty acids having 6 to 12 carbon atoms, long-chain saturated fatty acids having 13 or more carbon atoms, and long-chain unsaturated fatty acids having 13 or more carbon atoms. Examples of fatty acids include, but are not limited to, stearic acid, lauric acid, palmitic acid, myristic acid, caprylic acid, capric acid, oleic acid, linoleic acid, linolenic acid, arachidonic acid, eicosapentaenoic acid, and docosahexaenoic acid. In this embodiment, surface treatment agents other than fatty acids can be used. Examples of surface treatment agents other than fatty acids include silane coupling agents.

[0023] The content of calcium carbonate is preferably 5 parts by mass or more and 80 parts by mass or less, and more preferably 5 parts by mass or more and 50 parts by mass or less, relative to 100 parts by mass of vinyl chloride resin.

[0024] <Antimony oxide> In this embodiment, antimony oxide is added as a flame retardant. When antimony oxide is used in combination with a halogen element contained in the vinyl chloride resin, it is expected to have the effect of improving flame retardancy. The antimony oxide is not particularly limited, but examples thereof include antimony trioxide and antimony pentoxide. The antimony oxide is preferably antimony trioxide.

[0025] <Clay> In this embodiment, clay is added as an insulating property improver. In this embodiment, it is preferable to add calcined clay.

[0026] <Silicone lubricant> In this embodiment, a silicone lubricant grafted with an acrylic group is added. Adding the silicone lubricant grafted with an acrylic group can prevent a decrease in the lubricating effect of the silicone lubricant. This can prevent a decrease in the effect of absorbing stress applied to the vinyl chloride resin composition during wear. As a result, the wear resistance of the vinyl chloride resin composition can be improved. Furthermore, adding the silicone lubricant grafted with an acrylic group can increase the content of plasticizer. This can improve the cold resistance of the vinyl chloride resin composition.

[0027] In this embodiment, the content of the acrylic group-grafted silicone lubricant is 0.5 parts by mass or more per 100 parts by mass of vinyl chloride resin. This more reliably improves the lubricity of the vinyl chloride resin composition. As a result, the abrasion resistance of the vinyl chloride resin composition can be improved. In this embodiment, the content of the acrylic group-grafted silicone lubricant is 5 parts by mass or less per 100 parts by mass of vinyl chloride resin. This prevents a decrease in supply stability during extrusion of the wire / cable coating. The content of the acrylic group-grafted silicone lubricant is preferably 1 part by mass or more and 5 parts by mass or less per 100 parts by mass of vinyl chloride resin. This further improves the abrasion resistance of the vinyl chloride resin composition.

[0028] <Additives> The vinyl chloride resin composition of the present embodiment may further contain various additives, such as antioxidants, insulating improvers, flame retardants, and other additives, as long as the additives do not impair the effects of the present invention.

[0029] The antioxidant in this embodiment is preferably at least one of a phenol-based antioxidant and an amine-based antioxidant. Examples of the phenol-based antioxidant include pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] (CAS No. 6683-19-8), 2,2'-thiodiethylbis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] (CAS No. 41484-35-9), n-octadecyl 3-(3',5'-di-t-butyl-4'-hydroxyphenyl)propionate (CAS No. 2082-79-3), and octyl-3,5-ditert-butyl-4-hydroxyphenylpropionate (CAS No. 2082-79-3). t-Butyl-4-hydroxy-hydrocinnamate (CAS No. 125643-61-0), 2,4-bis[(dodecylthio)methyl]-6-methylphenol (CAS No. 110675-26-8), benzenepropanoic acid, 3-(1,1-dimethylethyl)-4-hydroxy-5-methyl-, 1,2-ethanediylbis(oxy-2,1-ethanediyl) ester (CAS No. 36443-68-2), 1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)-1,3,5-triazine-2,4 ,6(1H,3H,5H)-trione isocyanuric acid tris(3,5-di-tert-butyl-4-hydroxybenzyl) (CAS No. 27676-62-6), 1,1,3-tris(2-methyl-4-hydroxy-5-tert-butylphenyl)butane (CAS No. 1843-03-4), 4,4'-butylidenebis(6-tert-butyl-m-cresol) (CAS No. 85-60-9), 2,2'-dimethyl-2,2'-(2,4,8,10-tetraoxaspiro[5.5]undecane-3,9-diyl )dipropane-1,1'-diyl bis[3-(3-tert-butyl-4-hydroxy-5-methylphenyl)propanoate] (CAS No. 90498-90-1), 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene (CAS No. 1709-70-2), 4,4',4'',4'''-methanetetrayltetraphenoltetrakis(4-hydroxyphenyl)methane 4-[tris(4-hydroxyphenyl)methyl]phenol (CAS No.53184-78-4), N,N'-(1,3-propanediyl)bis[3,5-di-tert-butyl-4-hydroxybenzenepropanamide] (CAS No. 69851-61-2), N,N'-(hexane-1,6-diyl)bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propanamide] (CAS No. 23128-74-7), 2-methyl-4,6-bis[(n-octylthio)methyl]phenol (CAS No. 110553-27-0), tris(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)isocyanurate (CAS No. 40601-76-1), 3-(1,1-dimethyl)benzenepropanoate Examples of suitable antioxidants include 3-(3,5-di-tert-butyl-4-hydroxyphenyl)-N'-[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propanoyl]propanehydrazide (CAS No. 32687-78-8) and bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propanoic acid][oxalylbis(azanediyl)]bis(ethane-2,1-diyl) (CAS No. 70331-94-1). The above phenolic acid antioxidants may be used alone or in combination of two or more. The method for adding the phenolic acid antioxidant or a mixture thereof is not particularly limited, but examples include mixing it with a resin to form a masterbatch.

[0030] Amine antioxidants include poly(1,2-dihydro-2,2,4-trimethylquinoline) (CAS No. 26780-96-1), ethoxyquin (CAS No. 91-53-2), reaction product of diphenylamine with acetone (CAS No. 68412-48-6), N-(1,3-dimethylbutyl)-N'-phenyl-1,4-phenylenediamine (CAS No. 793-24-8), N-isopropyl-N'-phenylbenzene-1,4-diamine (CAS No. 1 Examples of suitable antioxidants include N,N'-di-2-naphthyl-1,4-phenylenediamine (CAS No. 93-46-9), 4'-anilinotoluene-4-sulfonanilide (CAS No. 100-93-6), 4,4'-bis(α,α-dimethylbenzyl)diphenylamine (CAS No. 10081-67-1), di(4-octylphenyl)amine (CAS No. 101-67-7), and N-phenyl-1-naphthylamine (CAS No. 90-30-2). The preferred phenolic antioxidant is pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] (CAS No. 6683-19-8). The method for adding the amine antioxidant or a mixture thereof is not particularly limited, and examples include mixing it with a resin to form a masterbatch.

[0031] To achieve a more excellent antioxidant function, it is more preferable to use it in combination with a sulfur-containing compound such as pentaerythritol tetrakis[3-laurylthiopropionate] (CAS No. 29598-76-3) or ditridecyl 3,3'-thiobispropionate (CAS No. 10595-72-9).

[0032] In addition to the trimellitic acid esters described above, polyesters, pyromellitic acid esters, and the like can be added as plasticizers. The molecular weight and chemical structure of the polyester-based plasticizer are not particularly limited. Examples of the chemical structure of polyester-based plasticizers include adipic acid-based, sebacic acid-based, and aromatic-based. Examples of polyester-based plasticizers include adipic acid-based polyesters, sebacic acid-based polyesters, and aromatic polyesters. The content of the polyester-based plasticizer is preferably 5 parts by mass or more and less than 30 parts by mass, more preferably 10 parts by mass or more and 20 parts by mass or less, per 100 parts by mass of vinyl chloride resin.

[0033] By setting the content of the polyester-based plasticizer within the above range, the amount of hydrogen chloride gas generated during combustion of the vinyl chloride resin composition can be suppressed. Furthermore, the oil resistance and electrical properties of the vinyl chloride resin composition can be improved. In particular, when the content of the polyester-based plasticizer is 10 parts by mass or more and 20 parts by mass or less per 100 parts by mass of vinyl chloride resin, the amount of hydrogen chloride gas generated during combustion can be reduced to 80 mg / g or less. Furthermore, the tensile elongation retention after immersion in IRM902 oil at 85°C for 4 hours can be increased to 70% or more. Furthermore, electrical properties can also be improved.

[0034] Polyester plasticizers come in a wide variety of types, with viscosities at 25°C ranging from 100 mPa·s to 10,000 mPa·s. The viscosity of polyester plasticizers at 25°C is preferably greater than 800 mPa·s, more preferably 1,000 mPa·s to 5,000 mPa·s, and even more preferably 1,500 mPa·s to 3,500 mPa·s. This reduces the amount of hydrogen chloride gas generated during combustion of the vinyl chloride resin composition. It also improves the oil resistance and electrical insulation of the vinyl chloride resin composition.

[0035] Examples of pyromellitic acid esters include pyromellitic acid 2-ethylhexyl ester and pyromellitic acid mixed linear alkyl ester. Although there are environmental concerns, the addition of phthalic acid esters is not restricted as long as they are not prohibited substances.

[0036] In addition to calcium carbonate, at least one of zinc stannate and zinc borate can be added as a stabilizer. As a result, a shell (char) that covers the entire material is generated during the combustion of the vinyl chloride resin composition. Consequently, it is possible to prevent hydrogen chloride gas from being discharged outside the system. Compounds containing a large number of hydroxyl groups, such as zinc hydroxystannate, may reduce the electrical insulation of the material, so it is preferably not used when the application is an electric wire coating material. The content of stabilizers other than calcium carbonate is preferably 2 parts by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the vinyl chloride resin.

[0037] In addition to those described above, other additive components can be further blended into the vinyl chloride resin composition as needed. Examples of such additive components include lubricants, surfactants, inorganic and organic fillers, reinforcing agents, fillers, crosslinking agents, silicon coupling agents, compatibilizers, copper damage inhibitors, ultraviolet absorbers, light stabilizers, colorants, and the like.

[0038] <shoreA hardness> The shoreA hardness of the vinyl chloride resin composition according to this embodiment is preferably 90 or less. The shoreA hardness can be measured by the method defined in JCS Z 2246.

[0039] <Brittleness temperature> The brittleness temperature of the vinyl chloride resin composition according to this embodiment is preferably -15°C or less. The brittleness temperature is defined as the highest temperature at which all 3 test pieces do not break when measured in 1°C increments with 3 test pieces of test piece A shape shown in JIS K 7216 4-1, and can be measured by using the method defined in JIS K 7216 other than the above definition.

[0040] (Preparation of vinyl chloride resin composition) The vinyl chloride resin composition can be prepared by mixing and melt-kneading the above-described components using a kneading device such as a batch kneader, e.g., a Banbury mixer or a pressure kneader, or a continuous kneader, e.g., a twin-screw extruder.

[0041] The vinyl chloride resin composition obtained as described above can be a vinyl chloride resin composition having improved abrasion resistance.

[0042] <<Wire>> The electric wire according to this embodiment has an insulating layer made of the vinyl chloride resin composition. As an example of this electric wire, as shown in Fig. 1, an electric wire 9 in which the outer periphery of a conductor 8 is covered with an insulating layer 11 can be exemplified. In this case, the insulating layer 11 is made of the vinyl chloride resin composition described above.

[0043] Here, the conductor 8 is, for example, a commonly used metal wire. For example, copper wire, copper alloy wire, aluminum wire, gold wire, or silver wire can be used as the conductor 8. Alternatively, a metal wire plated with metal such as tin or nickel can be used as the conductor 8. Furthermore, a twisted conductor made by twisting metal wires can also be used as the conductor 8.

[0044] The electric wire according to this embodiment preferably has a rated temperature of 105° C. or higher as specified by the UL standard.

[0045] The electric wire according to the present embodiment preferably satisfies the flame retardancy VW-1 specified by the UL standard. Here, "satisfying the flame retardancy VW-1" means passing the vertical flame test in the UL standard.

[0046] Fig. 2 is a diagram showing a schematic configuration of an example of an extruder for producing an electric wire according to this embodiment. As shown in Fig. 2, the extruder 1 includes a cylinder 10, a screw 3 rotatably provided within the cylinder 10, a hopper 2 for supplying material into the cylinder 10, and a crosshead 6. The extruder 1 also includes a neck 5 between the crosshead 6 and the screw 3, and a breaker plate 4 between the neck 5 and the screw 3. The crosshead 6 has a die 7. A conductor 8 passing through the crosshead 6 is coated with an insulating layer within the crosshead 6, passes through the die 7, and is drawn out from the crosshead 6 as an electric wire 9.

[0047] <<Cable>> 1 may be bundled together to form a cable 13. An example of this cable 13 is a cable 13 in which the outer periphery of a conductor 8 is covered with an insulating layer 11, and the outer periphery of the wire is further covered with a covering layer (sheath) 12, as shown in FIG.

[0048] 1, the insulating layer 11 may be made of an insulating material typically used for insulating wires. Examples of insulating materials for the insulating layer 11 include polyvinyl chloride, fluororesin, cross-linked polyethylene, natural rubber, synthetic rubber, etc. Preferably, the insulating layer 11 is made of the vinyl chloride resin composition described above.

[0049] The covering layer (sheath) 12 is made of the vinyl chloride resin composition described above. When bundling multiple electric wires, the wires are bundled together with a filler and a pressure winding tape is applied to the outer periphery, thereby forming the covering layer (sheath) 12 as the outermost layer.

[0050] The cable according to this embodiment preferably has a rated temperature of 105° C. or higher as specified by the UL standard.

[0051] The cable according to the present embodiment preferably satisfies the flame retardancy VW-1 specified by the UL standard. Here, "satisfying the flame retardancy VW-1" means passing the vertical flame test in the UL standard.

[0052] A method for manufacturing cable 13 may be mentioned in which, in the same manner as in the above-mentioned method for manufacturing an electric wire, conductor 8 is replaced with electric wire 9, and an extruder is used to form a coating layer (sheath) by covering the outer periphery of electric wire 9 with the vinyl chloride resin composition described above. [Example]

[0053] The following embodiments are examples of wire and cable production using the vinyl chloride resin composition of the present invention as an electric wire insulator or a cable sheath, for the purpose of understanding the present invention. There are no limitations on the type of conductor, structure, interposition, semiconductive layer, hold-down tape, shielding braid, or reinforcing layer of the electric wire or cable structure or application.

[0054] The following describes one embodiment of kneading vinyl chloride resin with various additives, preparing a sheet for evaluating the properties of the vinyl chloride resin composition, and preparing an electric wire using the vinyl chloride resin composition, but the present invention is not limited thereto. The electric wire to be prepared is also one example, and a cable shape may be obtained by applying extrusion coating to an electric wire (a conductor coated with an insulator). There are no limitations on the extrusion conditions, conductor and insulator materials, or electric wire / cable structure.

[0055] The internal mixer kneader used in the following examples will be given as an example. Other kneading devices are not particularly limited as long as they are commonly used, such as a roller mill, extruder, kneader, mixer, autoclave, etc. Furthermore, there are no limitations on the kneading conditions.

[0056] <Mixing vinyl chloride resin with various additives> The vinyl chloride resin and various additives were all weighed into a stainless steel container, heated at 90°C for 4 hours, and then left at room temperature overnight (to allow the plasticizer to dry up). The weighed amounts are shown in Table 1. The materials in the stainless steel container were stirred and then placed in a 200 mL sealed mixer kneader (two-blade rotor) whose kneading vessel had been preheated to 160°C. Once all the materials were in the vessel, the pressure lid was removed and kneading began at a rotor rotation speed of 30 rpm. Ten minutes after the start of kneading, the rotor rotation was stopped (kneading completed), the pressure lid was lifted, and the materials were removed from the vessel.

[0057] <Preparation of characteristic evaluation sheet> The material was kneaded in a 6-inch roller at a roll surface temperature of 160°C and formed into a sheet (work was carried out quickly to avoid applying shear as much as possible).Then, a press molding machine was used to heat and press the material at 180°C for 5 minutes to produce a 2mm thick sheet for property evaluation.

[0058] <Making electric wires> The material (before press molding) formed into a sheet using the aforementioned 6-inch roller was pelletized into square pellets of approximately 4 mm square. The square pellets were then fed into a single-screw extruder, and an electric wire was produced by extrusion coating directly onto the conductor. The extruder settings are shown in Table 2. A conductor having a diameter of 1.25 SQ, made by twisting together multiple tin-plated annealed copper wires, was used. A vinyl chloride resin composition was extrusion coated onto the conductor to a thickness of 0.78 mm as an insulator (outermost layer). Table 1 shows Examples 1 to 4 and Comparative Examples 1 to 4, respectively.

[0059] [Table 1] *1: TH-1300 (for soft use), manufactured by Taiyo PVC *2: Trimex T-08A, manufactured by Kao Corporation *3: Manufacturer developed product *4: Lighton BSO, manufactured by Bihoku Nuka Kogyo Co., Ltd. *5: Antimony trioxide, manufactured by Twinkling Star *6: Calcined kaolin (Insulite LHM-103HP (Mizusawa Chemical Industries, Ltd.)) *7: Chaline R-175S, manufactured by Nissin Chemical Industry Co., Ltd.

[0060] [Table 2]

[0061] <<Evaluation>> The hardness, brittle temperature, abrasion resistance, and wire extrusion properties of the vinyl chloride resin compositions were evaluated as follows. The evaluation results are shown in Table 1.

[0062] <Hardness> Using a sheet for property evaluation, Shore A hardness was measured by the method specified in JCS Z 2246. Those with a Shore A hardness of 90 or less were deemed to have sufficient flexibility for practical use and were therefore judged to have passed (marked with a circle in Table 1). Those with a Shore A hardness of more than 90 were deemed to have insufficient flexibility for practical use and were therefore judged to have failed (marked with an x ​​in Table 1).

[0063] <Embrittlement temperature> A sheet for property evaluation was used, and the method specified in JIS K 7216 was used as a reference. However, the brittleness temperature determined this time was defined as the highest temperature at which none of the three test pieces broke when measurements were taken in 1°C increments using three test pieces, type A, specified in JIS K 7216 4-1. Test pieces with a brittleness temperature of -15°C or lower were considered to have passed (marked with a circle in Table 1). Test pieces with a brittleness temperature of more than -15°C were considered to have failed (marked with an x ​​in Table 1).

[0064] <Wear resistance> The test piece was a sheet for property evaluation, cut to a length of 100 mm and a width of 30 mm. Using the abrasion tester specified in JIS C 3005 4.29, the test piece was attached to a jig that simulated the shape of a cable, and the mass of the weight was set to 3 kg and the grinding wheel rotation speed was set to 100 revolutions. The abraded volume was calculated from the weight loss and specific gravity before and after the test.

[0065] An example in which no acrylic group-grafted silicone lubricant was added (Comparative Example 1) was used for comparison. Examples in Comparative Example 1 in which the reduction rate of the wear volume relative to the wear volume was less than 2% were deemed to have an insufficient reduction effect (denoted by × in Table 1) and were therefore deemed to have failed. Examples in which the reduction rate was 2% or more but less than 20% were deemed to have a sufficient reduction effect (denoted by ○ in Table 1). Examples in which the reduction rate was 20% or more were deemed to have an especially excellent reduction effect (denoted by ◎ in Table 1). Examples rated as ○ and ◎ were deemed to have passed.

[0066] <Wire extrusion workability (material supply stability)> The stability of feeding vinyl chloride resin composition pellets from a hopper into an extruder was evaluated. Examples in which the pellets loaded into the hopper were automatically transported by the screw were evaluated as good (marked with a circle in Table 1). Examples in which the amount of pellets transported by the screw became unstable and automatic feeding was deemed difficult, due to factors such as pellet blocking in the hopper or insufficient engagement by the screw due to excessive lubricity, were evaluated as poor (marked with an x ​​in Table 1). ○ was considered a pass, and x was considered a fail.

[0067] The evaluation criteria were hardness, embrittlement temperature, sheet wear volume, and supply stability during wire extrusion. Products that passed all criteria were judged as passing, and the rating was recorded as "pass" in the rating column of Table 1. Products that failed even one criterion were judged as failing, and the rating was recorded as "failed" in the rating column of Table 1.

[0068] It was found that all evaluation criteria could be met by adjusting the amount of acrylic group-grafted silicone lubricant added to 0.5 parts by mass or more and 5 parts by mass or less from the formulations shown in Examples 1 to 4. Furthermore, it was found that by adjusting the amount of acrylic group-grafted silicone lubricant added to 100 parts by mass of vinyl chloride resin to 1 part by mass or more and 5 parts by mass or less, better abrasion resistance could be imparted to the vinyl chloride resin composition.

[0069] Comparative Example 2 showed that when the amount of acrylic group-grafted silicone lubricant added was small, the effect of reducing wear volume was insufficient. Comparative Example 3 showed that when the amount of acrylic group-grafted silicone lubricant added was excessive, the pellet surface became too slippery, resulting in poor screw penetration and making stable automatic feeding difficult. Furthermore, Comparative Example 4 showed that while wear volume could be reduced by reducing the amount of plasticizer, this significantly reduced the flexibility and cold resistance of the vinyl chloride resin composition.

[0070] From the above, it was found that adding an acrylic group-grafted silicone lubricant is effective in achieving both sufficient abrasion resistance reduction and wire extrusion workability without impairing flexibility and cold resistance. Furthermore, it was found that in order to achieve the above effect, the amount of acrylic group-grafted silicone lubricant added must be 0.5 parts by mass or more and 5 parts by mass or less per 100 parts by mass of vinyl chloride resin. Furthermore, it was found that the abrasion resistance of the vinyl chloride resin composition can be further improved when the amount of acrylic group-grafted silicone lubricant added is 1 part by mass or more and 5 parts by mass or less per 100 parts by mass of vinyl chloride resin.

[0071] The vinyl chloride resin and additives used in this example are not limited in any way. Furthermore, the wire shape made of a conductor and a covering material (insulator) as prepared in this example is not limited either, and the cable can also be used in the form of a sheath made of the vinyl chloride resin composition of the present invention. In this case, the material for the inner layer of the insulator can be the vinyl chloride resin composition of the present invention or another resin composition.

[0072] According to the present invention, it is possible to provide a vinyl chloride resin composition, an electric wire, and a cable that are imparted with abrasion resistance without impairing flexibility or cold resistance.

[0073] The present invention has been described using the above-mentioned embodiments and examples, but the present invention is not limited to the above-mentioned embodiments and examples and can be modified in various ways without departing from the spirit of the invention. [Explanation of symbols]

[0074] 1. Extruder 2 Hopper 3 screws 4 Breaker Plate 5 Neck 6 Crosshead 7 Dice 8 Conductors 9 Electric wire 10 cylinders 11 Insulating layer 12 Covering layer 13 Cable

Claims

1. The lubricant comprises a vinyl chloride resin, a trimellitic ester, surface-treated calcium carbonate, antimony oxide, clay, and an acrylic group-grafted silicone lubricant; The vinyl chloride resin composition, wherein the content of the silicone lubricant is 0.5 parts by mass or more and 5 parts by mass or less relative to 100 parts by mass of the vinyl chloride resin.

2. In claim 1, The vinyl chloride resin composition, wherein the trimellitic acid ester is trimellitic acid tris-2-ethylhexyl ester.

3. In claim 1, The vinyl chloride resin composition, wherein the degree of polymerization of the vinyl chloride resin is 800 or more and 3,000 or less.

4. In claim 1 A vinyl chloride resin composition having a Shore A hardness of 90 or less.

5. In claim 1, A vinyl chloride resin composition having a brittle temperature of −15° C. or lower.

6. A conductor and an insulating layer covering the outer periphery of the conductor, An electric wire, wherein the insulating layer is made of the vinyl chloride resin composition according to any one of claims 1 to 5.

7. In claim 6, An electric wire having a rated temperature of 105°C or higher as specified by the UL standard and meeting the flame retardancy VW-1 as specified by the UL standard.

8. The cable includes a conductor, an insulating layer covering the outer periphery of the conductor, and a covering layer covering the periphery of the insulating layer, A cable, wherein the covering layer is made of the vinyl chloride resin composition according to any one of claims 1 to 5.

9. In claim 8, A cable that has a rated temperature of 105°C or higher as specified by the UL standard and meets the flame retardancy VW-1 standard as specified by the UL standard.

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