Halogen-containing resin composition and cables and wires using the same

Abstract

The present invention provides a resin composition that possesses the electrical properties required for an insulator and has improved heat resistance, as well as electric wires and cables using the same. [Solution] A halogen-containing resin composition comprising a base polymer (A), a plasticizer (B), a stabilizer (C), and an additive (F), wherein the base polymer (A) comprises polyvinyl chloride resin (a1), chlorinated polyethylene (a2), and urethane thermoplastic elastomer (a3), substantially free of metal hydroxides and antimony trioxide as flame retardants, and contains calcined clay (D), the stabilizer (C) comprises at least two of hydrotalcite, Ca-Zn-based stabilizers, and metal soaps, the additive (F) is present in an amount of 0.5 to 40 parts by mass per 100 parts by mass of the total amount of components (A) to (D), the additive (F) contains needle-shaped boehmite, and the volume resistivity at 30°C is 5E+13Ω·cm or more, wherein the halogen-containing resin composition.

Description

Technical Field

[0001] The present invention relates to a halogen-containing resin composition, a cable, and an electric wire using the same.

Background Art

[0002] A cable is configured, for example, by providing an outer skin layer (so-called sheath) as a covering material around an insulated electric wire in which an insulating layer is provided around a conductor. The outer skin layer is formed from a resin composition mainly made of rubber or resin.

[0003] This resin composition is required to have different characteristics depending on the use of the cable. For example, cables for FA (Factory Automation) robots are required to have flame retardancy and heat resistance. Therefore, as the resin composition, for example, a soft vinyl chloride resin composition (soft PVC) blended with a flame retardant, a copolymer of tetrafluoroethylene and ethylene (ETFE), or the like is used.

[0004] Particularly, in applications where flex resistance is required, ETFE, which is excellent in abrasion resistance and resilience, has often been applied. However, ETFE has problems such as high cost and the need to control back pressure using a rapid compression screw during extrusion molding.

[0005] Therefore, various alternative materials for this ETFE have been studied, and as one of the materials, a resin composition excellent in resilience and abrasion resistance has been studied. For example, a resin composition using chlorinated polyethylene as a base polymer and urethane thermoplastic elastomer (TPU) in combination is known (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Summary of the Invention

[0007] However, the resin composition described in Patent Document 1 above may not be sufficient in terms of heat resistance and electrical properties, making it difficult to apply, for example, as an insulator.

[0008] Therefore, the present invention aims to provide a resin composition containing TPU that has the electrical properties required for an insulator and improved heat resistance, as well as electric wires and cables using the same. [Means for solving the problem]

[0009] A halogen-containing resin composition according to one embodiment of the present invention is a halogen-containing resin composition comprising a base polymer (A), a plasticizer (B), and a stabilizer (C), wherein the base polymer (A) comprises polyvinyl chloride resin (a1), chlorinated polyethylene (a2), and urethane thermoplastic elastomer (a3), substantially free of metal hydroxides and antimony trioxide as flame retardants, and containing calcined clay (D).

[0010] A cable according to one embodiment of the present invention comprises a conductor, an insulating layer covering the conductor, and an outer sheath layer covering the insulating layer, wherein the outer sheath layer is composed of a halogen-containing resin composition comprising a base polymer (A), a plasticizer (B), and a stabilizer (C), the base polymer (A) comprising polyvinyl chloride resin (a1), chlorinated polyethylene (a2), and urethane thermoplastic elastomer (a3), substantially free of metal hydroxides and antimony trioxide as flame retardants, and containing calcined clay (D).

[0011] An electric wire according to one embodiment of the present invention comprises a conductor and an insulating layer covering the conductor, wherein the insulating layer is composed of a halogen-containing resin composition comprising a base polymer (A), a plasticizer (B), and a stabilizer (C), and the base polymer (A) comprises polyvinyl chloride resin (a1), chlorinated polyethylene (a2), and urethane thermoplastic elastomer (a3), and substantially does not contain metal hydroxides and antimony trioxide as flame retardants, and contains calcined clay (D). [Effects of the Invention]

[0012] According to the halogen-containing resin composition of this embodiment, a resin composition containing TPU can be obtained that has the electrical properties required for an insulator and also has improved heat resistance.

[0013] Therefore, the wires and cables of this embodiment can be wires and cables with good electrical properties and heat resistance. [Brief explanation of the drawing]

[0014] [Figure 1] This is a cross-sectional view perpendicular to the longitudinal direction of the cable according to this embodiment. [Figure 2] This figure schematically shows the phase structure of the resin composition of this embodiment. [Modes for carrying out the invention]

[0015] <Background of the inventors' research> The inventors have been engaged in the development of resin compositions for use as cable sheath materials, using polymer alloy technology of multiple halogen-based polymers and TPU as base polymers.

[0016] In the study of the sheath material, in the system with a flame retardant such as antimony trioxide or aluminum hydroxide added, a composition with a volume resistivity of 5E+13 Ω·cm or more, which is the criterion for judging as an insulator, could not be found, and it was found that it was difficult to use it as a sheath material as an insulator.

[0017] However, the present inventors have found that by using fired clay, the volume resistivity can be improved in a halogen-containing resin composition containing TPU and can be applied as a material for forming an insulator, and have completed the present invention.

[0018] <Embodiment> The present invention has been made based on the above findings. Hereinafter, the resin composition, electric wire, and cable according to an embodiment of the present invention will be described in detail with reference to the drawings.

[0019] FIG. 1 is a cross-sectional view perpendicular to the longitudinal direction of the cable according to the present embodiment. In this specification, the numerical range represented by "~" means a range including the numerical values described before and after "~" as the lower limit value and the upper limit value.

[0020] [Halogen-containing resin composition] First, in the present embodiment, a halogen-containing resin composition suitable for forming the outer skin layer of the cable will be described. The halogen-containing resin composition of the present embodiment includes a base polymer (A), a plasticizer (B), a stabilizer (C), and fired clay (D), and may include a colorant (E) and other additives (F) as necessary.

[0021] Hereinafter, each component contained in this halogen-containing resin composition will be described in detail.

[0022] [Base polymer (A)] In this embodiment, as the base polymer (A), a polymer containing a halogen-containing resin and TPU is used, and it is preferable to contain a plurality of types of halogen-containing resins as the halogen-containing resin. Examples of the plurality of types of halogen-containing resins used here include polyvinyl chloride resin, chlorinated polyethylene, chlorosulfonated polyethylene, polytetrafluoroethylene, polychlorotrifluoroethylene, polyvinylidene fluoride, polyvinyl fluoride, perfluoroalkoxy fluororesin, ethylene tetrafluoride - hexafluoropropylene copolymer, ethylene - tetrafluoroethylene copolymer, ethylene - chlorotrifluoroethylene copolymer, and the like.

[0023] Among them, it is preferable to contain polyvinyl chloride resin (a1) and chlorinated polyethylene (a2). Hereinafter, the case where these two types of halogen-containing resins are contained as components of the base polymer will be described as an example.

[0024] As the polyvinyl chloride resin (a1) used in this embodiment (hereinafter, may also be referred to as "PVC(a1)"), in addition to a homopolymer of vinyl chloride, a copolymer of vinyl chloride and other copolymerizable monomers, etc. can be used. As the copolymer, for example, a copolymer of vinyl chloride and ethylene, vinyl acetate, etc. can be used. Also, a partially crosslinked one may be used.

[0025] The K value of the polyvinyl chloride resin (a1) is preferably 65.7 to 94.9, and more preferably 71 to 85.6. By setting the K value to 65.7 or more, high heat resistance and flame retardancy can be obtained in the resin composition, and the affinity with the component (a2) is also excellent. On the other hand, if the average degree of polymerization becomes excessively high, the molding processability of the halogen-containing resin composition may decrease, but by setting the K value to 94.9 or less, the performance of the resin composition can be maintained high without sacrificing the molding processability. Note that as the polyvinyl chloride resin (a1), a plurality of those with different average degrees of polymerization may be used in combination.

[0026] The chlorinated polyethylene (a2) used in this embodiment (hereinafter sometimes referred to as "CPE(a2)") is a component that contributes to improving the flame retardancy and cold resistance of the resin composition. Chlorinated polyethylene (a2) is obtained by blowing chlorine gas into an aqueous suspension in which raw polyethylene is suspended and dispersed in water.

[0027] The amount of chlorine contained in chlorinated polyethylene (a2) is not particularly limited, but from the viewpoint of improving cold resistance and flame retardancy, it is preferably 20% by mass or more, and more preferably 20% by mass to 45% by mass. Note that multiple CPEs with different chlorine content may be used in combination.

[0028] The urethane thermoplastic elastomer (a3) ​​used in this embodiment (hereinafter sometimes referred to as "TPU(a3)") is a component that primarily imparts resilience and abrasion resistance to the resin composition. Generally, TPU is obtained by the reaction of a polyol, a diol, and an isocyanate, and has a hard, rigid segment and a flexible soft segment.

[0029] The urethane thermoplastic elastomer (a3) ​​used in this embodiment is not particularly limited as long as it is a urethane thermoplastic elastomer, and examples include adipate-based, lactone-based, or carbonate-based urethane thermoplastic elastomers.

[0030] The urethane thermoplastic elastomer is preferably a component containing at least one selected from adipate-based, lactone-based, and carbonate-based materials. The adipate-based material is a urethane thermoplastic elastomer (TPU) obtained by reaction with an adipic acid-based polyester polyol, diol, and isocyanate. The lactone-based material is, for example, a urethane thermoplastic elastomer (TPU) obtained by reaction with a caprolactane-based polyester polyol, diol, and isocyanate. The carbonate-based material is, for example, a urethane thermoplastic elastomer (TPU) obtained by reaction with a carbonate compound-based polyester polyol, diol, and isocyanate.

[0031] Known components can be used as diols, which are raw materials for TPU. Examples include ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, 1,3-butanediol, 1,6-hexanediol, 1,8-octanediol, 1,9-nonanediol, neopentyl glycol, 2-butyl-2-ethyl-1,3-propanediol, 3-methyl-1,5-pentanediol, 2-methyl-1,3-propanediol, 3,3,5-trimethylpentanediol, 2,4-diethyl-1,5-pentanediol, 1,12-octadecanediol, 1,2-alkanediol, 1,3-alkanediol, 1-monoglyceride, 2-monoglyceride, 1-monoglycerin ether, 2-monoglycerin ether, dimer diol, hydrogenated dimer diol, and the like.

[0032] As the isocyanate used as a raw material for TPU, known components can be used, for example, aliphatic diisocyanates such as hexamethylene diisocyanate, butane-1,4-diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, xylylene diisocyanate, and m-tetramethylxylylene diisocyanate. In addition, alicyclic diisocyanates such as isophorone diisocyanate, cyclohexane-1,4-diisocyanate, lysine diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, 1,3-bis(isocyanate-methyl)cyclohexane, methylcyclohexane diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, isopropylidene dicyclohexyl-4,4'-diisocyanate, and norbornane diisocyanate can be used. Furthermore, aromatic diisocyanates such as 1,5-naphthylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 4,4'-diphenyldimethylmethane diisocyanate, 4,4'-dibenzyle diisocyanate, dialkyldiphenylmethane diisocyanate, tetraalkyldiphenylmethane diisocyanate, 1,3-phenylenediisocyanate, 1,4-phenylenediisocyanate, tolylene diisocyanate, and tetramethylxylylene diisocyanate are also mentioned.

[0033] From the viewpoint of heat resistance in the resin composition, TPU(a3) is not particularly limited as long as it is adipate-based, lactone-based, or carbonate-based, but from the viewpoint of adjusting the hardness in the resin composition, adipate-based is preferred.

[0034] Adipate-based TPUs offer advantages not only in their ability to adjust hardness, but also in their superior affinity with polyvinyl chloride resin (a1) compared to lactone-based and carbonate-based TPUs. This makes it easier to form the phase structure described later in the resin composition that constitutes the outer sheath layer of the cable, allowing for more stable realization of various properties. This is because adipate-based TPUs, which have a structure derived from adipic acid, do not significantly impair the bonding strength of hydrogen bonds and urethane bonds in the hard segments even when additives are added, making it easier to maintain high levels of various properties.

[0035] The hardness of the adipate-based TPU is not particularly limited, but from the viewpoint of balancing the resilience and heat resistance of the resin composition, it is preferably 80A to 95A on the Shore A hardness scale, and more preferably 80A to 90A.

[0036] The amounts of each component (a1), (a2), and (a3) ​​described above are preferably such that, when the total base polymer (A) is considered to be 100% by mass, component (a1) is 1 to 40% by mass, component (a2) is 5 to 65% by mass, and component (a3) ​​is 1 to 40% by mass. By blending within this range, the characteristics obtained from each component can be expressed, and the resin composition can have a good balance of properties such as heat resistance, flame retardancy, resilience, and hardness.

[0037] Furthermore, the base polymer (A) may contain other polymer components other than those listed in (a1), (a2), and (a3) ​​above, as appropriate, within a range that does not impair the desired properties. Examples of other polymer components include ethylene-vinyl chloride copolymer, ethylene-vinyl acetate copolymer, styrene-based elastomer, ethylene-α-olefin copolymer, ethylene-acrylic acid ester copolymer, acrylic resin, or modified versions thereof.

[0038] When other polymer components are included, it is preferable that the other polymer components make up 30% by mass or less of the base polymer (A) by 100% by mass, and more preferably 20% by mass or less.

[0039] [Plasticizer (B)] Plasticizer (B) is a component that imparts flexibility to the resin composition. Known plasticizers used in this type of resin composition can be used as plasticizer (B). Examples of such plasticizers include trimellitic acid esters, phthalate esters, and adipic acid polyesters. Among these, trimellitic acid esters are preferred because they do not impair the various properties of the cable when applied to its outer sheath layer.

[0040] Compared to phthalate esters, trimellitic acid esters can maintain a higher heat resistance in resin compositions. Furthermore, they do not cause stickiness in resin compositions compared to adipic acid polyesters, thus improving handling when applied to the outer sheath of cables. Trimellitate esters may be used alone, but they may also be used in combination with other plasticizers, such as adipic acid polyesters, as long as the desired properties are not compromised.

[0041] Examples of trimellitic acid esters that can be used include tri-2-ethylhexyl trimellitic acid, tri-n-octyl trimellitic acid, tri-mixed alkyl trimellitic acid, and triisononyl trimellitic acid. Antioxidant-mixed types may also be used. In this case, phenolic antioxidants are generally used, and commercially available products contain 0.1 to 1% by mass of antioxidants in the trimellitic acid ester.

[0042] [Stabilizer (C)] Stabilizer (C) acts as a thermal stabilizer to suppress the degradation of PVC (a1) and CPE (a2) when preparing halogen-containing resin compositions, and is also a component that stabilizes the phase structure of the halogen-containing resin composition.

[0043] In this embodiment, from the viewpoint of selectively dispersing the base polymer in a polymer such as PVC(a1) or CPE(a2), it is preferable to use hydrotalcite (c1), a Ca-Zn-based stabilizer (c2), or a metal soap (c3) as the stabilizer (C). Hydrotalcite (c1), Ca-Zn-based stabilizer (c2), and metal soap (c3) are not particularly limited as long as they have excellent compatibility with PVC(a1) or CPE(a2), and known components can be used.

[0044] Hydrotalcite (c1) is a layered compound of magnesium and aluminum, and among these, those in which the elemental mass ratio (mass of Mg / mass of Al) in the compound is adjusted to 1.5 to 3.5 are preferred.

[0045] Ca-Zn-based stabilizer (c2) is a well-known Ca-Zn-based stabilizer used for PVC products, primarily in applications such as wire insulation for automobiles and home appliances (excluding power and communication cables), and in flexible PVC products such as medical devices.

[0046] Examples of metal soaps (C3) include those composed of fatty acids such as stearic acid, lauric acid, and octic acid, and metals such as calcium and zinc.

[0047] Furthermore, stabilizer (C) may include stabilizing aids as components other than those listed above. The stabilizing aids have no effect on TPU(a3) whether they are added or not, and act only on PVC(a1). Examples of stabilizing aids include dibenzoylmethane, stearylbenzoylmethane and their metal salts, polyhydric alcohols, trihydroxyethyl isocyanate, etc., which can be used in appropriate amounts as needed.

[0048] [Fired clay (D)] The calcined clay (D) is a component that improves the heat resistance and insulation properties of the resin composition. This calcined clay (D) has the function of adsorbing ionic substances in the resin composition and improving its electrical properties (insulation).

[0049] Examples of fired clay (D) include known clays that have been fired to reduce their moisture content. Here, the clay used as the raw material for fired clay is an aggregate of fine, adhesive particles, and is a natural mineral whose chemical composition mainly consists of silicon, aluminum, magnesium, alkali metals, alkaline earth metals, and water. Examples of this clay include a white powder that has been industrially refined from a natural ore mainly composed of hydrated aluminum silicate. Such clay is fired to reduce its moisture content to 1% by mass or less.

[0050] The fired clay (D) may be surface-treated. Surface treatment can be performed, for example, using an organosilane compound or a silane oligomer.

[0051] [Coloring agent (E)] The coloring agent (E) is a pigment, dye, etc., that can be used to color the resin composition to a desired color when incorporated into it. Known coloring agents incorporated into this type of resin composition can be used as the coloring agent (E) without any particular limitations.

[0052] Examples of colorants (E) include black colorants such as NBP-2425 (product name, manufactured by Nikko Bix Co., Ltd.) and white colorants such as AO-25 (product name, manufactured by ADEKA Corporation).

[0053] [Additive (F)] In addition to the components (A) to (D) above, the halogen-containing resin composition of this embodiment may also contain other additives (F) as needed. Examples of additives (F) include crosslinking aids, antioxidants (thermal aging inhibitors), copper damage inhibitors, lubricants, processing aids, flame retardants, and insulation improvers.

[0054] Examples of crosslinking aids include trimethylolpropane trimethacrylate (TMPT), triallyl isocyanurate, triallyl cyanurate, N,N'-metaphenylene bismaleimide, ethylene glycol dimethacrylate, zinc acrylate, and zinc methacrylate. When this halogen-containing resin composition is applied without crosslinking using electron beam crosslinking or the like, it is not necessary to add a crosslinking aid.

[0055] Examples of antioxidants include phenolic antioxidants, phosphorus-based antioxidants, and sulfur-based antioxidants. Examples of copper damage inhibitors include N-(2H-1,2,4-triazole-5-yl)salicylamide, bis[N2-(2-hydroxybenzoyl)hydrazide] dodecanediate, and 2',3-bis[[3-[3,5-di-tert-butyl-4-hydroxyphenyl]propionyl]]propionohydrazide, with 2',3-bis[[3-[3,5-di-tert-butyl-4-hydroxyphenyl]propionyl]]propionohydrazide being more preferable.

[0056] Examples of lubricants include hydrocarbon-based, fatty acid-based, fatty acid amide-based, ester-based, and alcohol-based lubricants.

[0057] Examples of processing aids include fatty acids such as ricinoleic acid, stearic acid, palmitic acid, and lauric acid, as well as their salts, esters, and polymethyl methacrylate.

[0058] Furthermore, to impart flame retardancy, flame retardants can be included in this type of resin composition; however, in this embodiment, the flame retardants are substantially free of antimony trioxide and metal hydroxides.

[0059] Examples of flame retardants that can be used here include brominated flame retardants and amorphous silica.

[0060] As a brominated flame retardant, for example, decabromodiphenylethane can be used. From the viewpoint of dispersibility, the average particle size of the brominated flame retardant is preferably 5 μm or less. The lower limit is not particularly limited, but for example, it is 0.2 μm.

[0061] For amorphous silica, it is preferable that the average particle size is 5 μm or less from the viewpoint of dispersibility. The lower limit is not particularly limited, but for example, it is 0.01 μm.

[0062] Examples of insulating improvers include needle-shaped boehmite and unfired additive clays with a different chemical structure from the fired clay (D) mentioned above. Adding these insulating aids further enhances the insulating effect achieved by incorporating the fired clay (D), which is preferable.

[0063] Needle-shaped boehmite is an elongated aluminum hydroxide mineral, and its aspect ratio is preferably 10 to 70 on average. Its average particle size is preferably 0.5 to 10 μm.

[0064] This additive clay has a different chemical structure from the calcined clay (D), and is preferably an uncalcined clay that has not undergone calcination treatment. This additive clay, for example, contains a moisture content of more than 1% by mass to about 10% by mass. Here, a difference in chemical structure can be exemplified by cases where, on a mass basis, the SiO2 content relative to the Al2O3 content of each component (SiO2 / Al2O3 (mass ratio)) is different. For example, calcined clay (D) has an SiO2 / Al2O3 (mass ratio) < 2, while this additive clay has an SiO2 / Al2O3 (mass ratio) ≥ 2, indicating a difference in the silica and alumina content ratios.

[0065] (phase structure) In the halogen-containing resin composition of this embodiment, the base polymers PVC(a1), CPE(a2), and TPU(a3) form a sea-island structure or spinodal dispersion, with PVC(a1) and CPE(a2) being miscible and the TPU(a3) component being phase-separated from them. Furthermore, the stabilizer (C) is more selectively dispersed in the miscible phase of PVC(a1) and CPE(a2) than in TPU(a3). As a result, the amount of additive components that penetrate TPU(a2) can be significantly reduced compared to conventional methods, and the decrease in urethane bonding strength and hydrogen bonding strength in the TPU(a3) component can be suppressed. This makes it possible to maintain the inherent properties of the TPU(a3) component at a high level.

[0066] Figure 2 schematically illustrates the structure of such a phase. In Figure 2, the matrix 21 contains miscible PVC (a1) and CPE (a2), as well as a stabilizer (C) and calcined clay (D) dispersed therein, and the TPU 22 consists of TPU (a3) ​​that exists in phase separation within the matrix 21.

[0067] (Content ratio) Next, we will explain the proportion of each component described above. The base polymer (A) is preferably contained in an amount of 50 to 95% by mass, and more preferably in an amount of 60 to 90% by mass, of 100% by mass of the resin composition. The plasticizer (B) is preferably contained in an amount of 1 to 30% by mass, and more preferably in an amount of 5 to 20% by mass, per 100% by mass of the resin composition. The stabilizer (C) is preferably contained in an amount of 1 to 15% by mass, and more preferably in an amount of 2 to 10% by mass, per 100% by mass of the resin composition. The calcined clay (D) is preferably contained in an amount of 0.1 to 10% by mass, and more preferably 1 to 5% by mass, per 100% by mass of the resin composition.

[0068] While the content of stabilizer (C) is not particularly limited, metal soap (c3) tends to reduce hydrogen bonding and urethane bonding in the hard segment of TPU (a3) ​​more easily than hydrotalcite (c1), potentially impairing the heat resistance of the outer layer. Therefore, from the perspective of stabilizing PVC (a1) and CPE (a2) while maintaining high heat resistance, it is preferable to reduce the content of metal soap (c3) while increasing the content of hydrotalcite (c1) to ensure the effect of stabilizer (C).

[0069] Furthermore, when a coloring agent (E) is included, its content is preferably 0.1 to 5 parts by mass, and more preferably 0.5 to 2 parts by mass, based on 100 parts by mass of the total amount of components (A) to (D) above.

[0070] When additive (F) is included, its content is preferably 0.5 to 40 parts by mass, and more preferably 4 to 20 parts by mass, based on 100 parts by mass of the total amount of components (A) to (D) above.

[0071] (Preparation of halogen-containing resin composition) The halogen-containing resin composition can be prepared by mixing the above components (A) to (D) and, if necessary, a colorant (E) and other additives (F), and then melt-kneading them together. Kneading can be carried out using known kneading equipment, such as batch kneaders like Banbury mixers and pressure kneaders, or continuous kneaders like twin-screw extruders.

[0072] Specifically, one example is a method in which a chlorine-based resin composition is obtained by first kneading polyvinyl chloride resin (a1), chlorinated polyethylene (a2), plasticizer (B), stabilizer (C), and calcined clay (D), and then TPU (a3) ​​is mixed in and melt-kneaded. This allows for the dispersion of TPU(a3) in a chlorine-based resin composition to form a halogen-containing resin composition.

[0073] According to the above, in the halogen-containing resin composition, it is not necessary to pre-form the chlorine-based resin composition into pellets; the TPU(a3) pellets can be added to the molten TPU(a3) and kneaded. This kneading procedure reduces the penetration of additives into the TPU(a3) phase. As a result, it is possible to maintain a higher heat resistance in the resin composition, making it suitable, for example, as an outer sheath layer for cables.

[0074] When using a twin-screw extruder in the kneader, from the viewpoint of quantitative supply of the mixed materials, it is preferable to mix and dry the PVC (a1), plasticizer (B), and additives together, and then add and mix the CPE (a2) to maintain the powder form. Maintaining the powder state makes it easy to mix with TPU (a3) ​​pellets and also facilitates material supply using a screw feeder.

[0075] Furthermore, it is possible to provide the above-mentioned intermediate resin composition by first granulating (pelletizing) the chlorine-based resin composition and then mixing and kneading or extruding it with TPU(a3). This method is effective when it is necessary to quickly produce multiple types of materials with varying hardness, abrasion resistance, and flame retardancy of the chlorine-based resin composition.

[0076] The halogen-containing resin composition obtained as described above can have a composition that results in a volume resistivity of 5E+13Ω·cm or higher, and furthermore, can have high heat resistance that meets the UL standard of 105°C.

[0077] [cable] Next, a cable, which is one embodiment of the present invention, will be described with reference to Figure 1. Figure 1 is a cross-sectional view perpendicular to the length direction of the cable according to this embodiment.

[0078] As shown in Figure 1, the cable 1 of this embodiment is composed of a wire 10 with an insulating layer 12 formed around a conductor 11, a shield layer 13 provided around the wire 10, and an outer sheath layer 14 formed around the shield layer 13.

[0079] (conductor) The conductor 11 can be any metal wire commonly used in electric wires, such as copper wire or copper alloy wire, as well as aluminum wire, gold wire, silver wire, etc., without any particular restrictions. Furthermore, a metal wire plated with tin, nickel, or other metals may be used as the conductor 11. Additionally, a stranded wire, made by twisting metal wires together, can also be used as the conductor 11.

[0080] (Insulating layer) The insulating layer 12 is a coating layer made of insulating material that is provided around the conductor 11. The insulating layer 12 can be formed from conventionally known materials, such as polymers like fluororesin, polyester resin, or high-density polyethylene, or resin compositions to which flame retardants, antioxidants, etc., have been added to the polymer, or it may be formed from the halogen-containing resin composition described above. The thickness of the insulating layer 12 is not particularly limited, but is preferably, for example, 0.1 mm to 1.5 mm.

[0081] (Shield layer) The shield layer 13 is an electromagnetic shielding layer provided around a stranded wire formed by twisting together multiple electric wires 10. The shield layer 13 can be any known shield layer without particular limitation, and is formed, for example, by a braided structure in which multiple metal strands such as soft copper wire are woven together.

[0082] (outer skin layer) The outer sheath layer 14 is provided around the shield layer 13 and is a covering layer that forms the outermost layer of the cable 1. In this embodiment, the outer sheath layer 14 is formed from the halogen-containing resin composition described above. The thickness of the outer sheath layer 14 is not particularly limited, but from the viewpoint of obtaining a good balance of various properties at a high level, it is preferable to have a thickness of 0.1 mm to 1.4 mm.

[0083] From the viewpoint of improving the oil resistance and flame extinction stability of the outer layer 14 during combustion, the halogen-containing resin composition may be crosslinked. The crosslinking method is not particularly limited, and for example, electron beam crosslinking can be used. If electron beam crosslinking is performed, the extruded halogen-containing resin composition is irradiated with an electron beam of 0.5 to 30 Mrad to crosslink it.

[0084] (How to manufacture cables) First, a conductor 11 is prepared, and using an extrusion molding machine, for example, the halogen-containing resin composition of this embodiment described above is extruded to cover the conductor 11, forming an insulating layer 12 of a predetermined thickness, thereby obtaining an electric wire 10. Subsequently, multiple electric wires 10 are twisted together, and a shield layer 13 is formed around them using a braiding machine.

[0085] Next, the halogen-containing resin composition of this embodiment is extruded using an extrusion molding machine to cover the periphery of the shield layer 13, thereby forming an outer sheath layer 14 of a predetermined thickness. This allows the cable 1 of this embodiment to be manufactured.

[0086] In this embodiment, the above-described halogen-containing resin composition has been primarily described in relation to the use of the halogen-containing resin composition in the outer sheath layer of a cable, but the present invention is not limited thereto. The halogen-containing resin composition of this embodiment can also be used, for example, in the insulating layer of an electric wire. This is because the insulating resistance of the halogen-containing resin composition increases, and it is possible to achieve performance as an insulated electric wire. [Examples]

[0087] Next, the present invention will be described in more detail based on examples, but the present invention is not limited to these examples.

[0088] <Material> In this embodiment, the materials used to prepare the halogen-containing resin composition for forming the outer layer are as follows:

[0089] [Base polymer (A)] The following components were used as the base polymer (A). Polyvinyl chloride resin (a1) is polyvinyl chloride resin 1 (product name "TH-1700", manufactured by Taiyo Vinyl Chloride Co., Ltd., K value 75.7~78.1) As chlorinated polyethylene (a2), chlorinated polyethylene 1 (product name "Elaslene 352GB", manufactured by Showa Denko Corporation, chlorine content 34% to 37% by mass) As a urethane thermoplastic elastomer (a3), adipate-type TPU (product name "P25MRWJE", manufactured by Nippon Miractran Co., Ltd., Shore A hardness 90)

[0090] [Plasticizer (B)] As the plasticizer (B), (b1) di-2-ethylhexyl trimellitate (TOTM) (product name "T08", manufactured by Kao Corporation) was used.

[0091] [Stabilizer (C)] The following was used as stabilizer (C): • (c1) Stabilizer 1 (Product name "HT-1", manufactured by Sakai Chemical Industry Co., Ltd.; hydrotalcite) • (c2) Stabilizer 2 (Product name "OW-3152", manufactured by Sakai Chemical Industry Co., Ltd.; Ca-Zn-based stabilizer)

[0092] [Fired clay (D)] As the calcined clay (D), calcined clay 1 (product name: SP#33, manufactured by BASF; SiO2 / Al2O3 (mass ratio) < 2) was used.

[0093] [Coloring agent (E)] As a coloring agent (E), (e1) Color Batch (product name "NBP-2425Black", manufactured by Nikko Bigs Co., Ltd.) was used.

[0094] [Additives (F)] The following was used as additive (F): • (f1) Cube-shaped boehmite (product name "Cerasure BMB-2", manufactured by Kawai Lime Industry Co., Ltd.; average particle size 2 μm) • (f2) Needle-shaped boehmite (product name "Cerasure BMI", manufactured by Kawai Lime Industry Co., Ltd.; major diameter 5 μm, aspect ratio 40) • (f3) Calcium carbonate (product name "Softon 1200", manufactured by Bihoku Powdering Industry Co., Ltd.) • (f4) Talc (product name "Micro Ace L1", manufactured by Nippon Talc Co., Ltd.) • (f5) Additive clay (product name "Insulite LHM103HP", manufactured by Mizusawa Chemical Industry Co., Ltd.; uncalcined, SiO2 / Al2O3 (mass ratio) ≥ 2)

[0095] <Example 1> First, the above materials were weighed to match the proportions shown in Table 1, and a mixture of all materials except TPU and TPU were prepared.

[0096] The mixture, excluding the TPU, was kneaded at 180°C for 5 minutes using a 6-inch roll. After kneading, the TPU pellets were added in small amounts while the mixture was still wrapped around the 6-inch roll. Once the addition was complete, the mixture was kneaded for 3 minutes with a roll gap of 1 mm thickness.

[0097] After that, the roll gap was set to a thickness of 0.5 mm and the sheet was produced. The sheet material was cut to fit a 0.5 mm thick metal frame, preheated to 180°C and 2 MPa for 3 minutes using a 100t press, pressurized to 10 MPa for 2 minutes, and then cooled with cooling water for 5 minutes to obtain a sheet of the desired shape.

[0098] <Examples 2-3, Comparative Examples 1-3> In Examples 2-3 and Comparative Examples 1-3, the resin compositions and sheets were prepared using the same procedure as in Example 1, except that the formulations were as shown in Table 1.

[0099] <Rating> The tensile properties, heat resistance, volume resistivity, and cold resistance of each sheet prepared in Examples 1-3 and Comparative Examples 1-3 were evaluated. Each evaluation was performed as follows. These results are summarized in Table 1.

[0100] [Table 1]

[0101] [Tensile properties] Tensile tests were performed on the prepared 0.5 mm thick samples in accordance with JIS K 6723 to measure the initial tensile strength, elongation, and 50% modulus.

[0102] [Heat resistance] For the samples used in the above tensile properties, a load was applied to a dumbbell piece conforming to JIS K 6723 using a gear oven with a ventilation rate specified in accordance with UL758 at 145°C for 120 hours, and the remaining tensile strength and elongation were determined from the relationship (tensile properties after loading × 100 / initial tensile properties).

[0103] [Volume resistivity] The volume resistivity of the fabricated 0.5 mm thick sample was measured at 30°C in accordance with JIS K 6723.

[0104] [Cold resistance] The fabricated 0.5 mm thick samples were subjected to embrittlement tests in accordance with JIS K 6723 to evaluate their cold resistance. The test temperature was -50°C. Samples that remained intact after the test (cracks were not included in the definition of failure) were marked as "pass" (symbol: ○), while samples that were destroyed after the test (separated into two or more pieces) were marked as "fail" (symbol: ×).

[0105] In Examples 1 to 3, favorable results were obtained in all of the above tests. In particular, the volume resistivity, which is applicable as an insulating material, was satisfied with a value of 5E+13Ω·cm or higher. Although the mechanism of this improvement in volume resistivity is not clear, in Example 1, it is presumed that the absence of flame retardants such as antimony and aluminum hydroxide increased the interfacial area between the calcined clay and the polymer component, allowing the calcined clay to effectively adsorb ionic substances and improve the electrical properties.

[0106] Furthermore, in Examples 2 and 3, it is presumed that the inclusion of additives increased the adsorption of both anionic and cationic ionic substances, thereby suppressing the degradation of TPU due to halogenated polymer decomposition products, and consequently improving the electrical properties.

[0107] In Comparative Examples 1 and 2, compositions were used with added calcium carbonate and talc, which are conventionally thought to have a negligible effect on the reduction of volume resistivity. However, the volume resistivity of 5E+13Ω·cm or higher was not satisfied. Furthermore, Comparative Example 3 is an example where the shape of the boehmite differs from that of Example 1, but in this case as well, the volume resistivity was not satisfied.

[0108] Although the present invention has been specifically described above based on its embodiments, 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]

[0109] 1 Cable 10 Electric wire 11 Conductors 12 Insulating layer 13 Shield Layer 14. Outer layer (sheath)

Claims

1. A halogen-containing resin composition comprising a base polymer (A), a plasticizer (B), a stabilizer (C), and an additive (F), The base polymer (A) comprises polyvinyl chloride resin (a1), chlorinated polyethylene (a2), and urethane thermoplastic elastomer (a3). As a flame retardant, it substantially does not contain metal hydroxides and antimony trioxide. Contains calcined clay (D), The stabilizer (C) contains at least two of the following: hydrotalcite, Ca-Zn-based stabilizer, and metal soap. The additive (F) is contained in an amount of 0.5 to 40 parts by mass per 100 parts by mass of the total amount of components (A) to (D). The additive (F) contains needle-shaped boehmite, The volume resistivity at 30°C is 5E + 13 Ω·cm or greater. Halogen-containing resin composition.

2. In the halogen-containing resin composition according to claim 1, Furthermore, a halogen-containing resin composition containing a coloring agent (E).

3. In the halogen-containing resin composition according to claim 1, A halogen-containing resin composition wherein the needle-shaped boehmite has an aspect ratio of 10 to 70 on average and an average particle size of 0.5 to 10 μm along its longest axis.

4. A cable comprising a conductor, an insulating layer covering the conductor, and an outer sheath layer covering the insulating layer, The outer layer is composed of a halogen-containing resin composition comprising a base polymer (A), a plasticizer (B), a stabilizer (C), and an additive (F). The base polymer (A) comprises polyvinyl chloride resin (a1), chlorinated polyethylene (a2), and urethane thermoplastic elastomer (a3). As a flame retardant, it substantially does not contain metal hydroxides and antimony trioxide. Contains calcined clay (D), The stabilizer (C) contains at least two of the following: hydrotalcite, Ca-Zn-based stabilizer, and metal soap. The additive (F) is contained in an amount of 0.5 to 40 parts by mass per 100 parts by mass of the total amount of components (A) to (D). The additive (F) contains needle-shaped boehmite, The volume resistivity at 30°C is 5E + 13 Ω·cm or greater. ,cable.

5. A wire comprising a conductor and an insulating layer covering the conductor, The insulating layer is composed of a halogen-containing resin composition comprising a base polymer (A), a plasticizer (B), a stabilizer (C), and an additive (F). The base polymer (A) comprises polyvinyl chloride resin (a1), chlorinated polyethylene (a2), and urethane thermoplastic elastomer (a3). As a flame retardant, it substantially does not contain metal hydroxides and antimony trioxide. Contains calcined clay (D), The stabilizer (C) contains at least two of the following: hydrotalcite, Ca-Zn-based stabilizer, and metal soap. The additive (F) is contained in an amount of 0.5 to 40 parts by mass per 100 parts by mass of the total amount of components (A) to (D). The additive (F) contains needle-shaped boehmite, The volume resistivity at 30°C is 5E + 13 Ω·cm or greater. Electric wire.

6. A halogen-containing resin composition comprising a base polymer (A), a plasticizer (B), a stabilizer (C), and an additive (F), The base polymer (A) comprises polyvinyl chloride resin (a1), chlorinated polyethylene (a2), and urethane thermoplastic elastomer (a3). As a flame retardant, it substantially does not contain metal hydroxides and antimony trioxide. Contains calcined clay (D), The stabilizer (C) contains at least two of the following: hydrotalcite, Ca-Zn-based stabilizer, and metal soap. The additive (F) is contained in an amount of 0.5 to 40 parts by mass per 100 parts by mass of the total amount of components (A) to (D). The additive (F) contains unfired clay, Based on the mass standard, Al of the fired clay (D) ３ , ２ O ３ The content of SiO with respect to the content of ２ is less than 2 (SiO ２ / Al ２ O ３ (mass ratio) < 2), and Al of the unfired clay ２ O ３ The content of SiO with respect to the content of ２ is 2 or more (SiO ２ / Al ２ O ３ (mass ratio) ≥ 2) And, The volume resistivity at 30°C is 5E + 13 Ω·cm or greater. Halogen-containing resin composition.

7. A cable comprising a conductor, an insulating layer covering the conductor, and an outer sheath layer covering the insulating layer, The outer layer is composed of a halogen-containing resin composition comprising a base polymer (A), a plasticizer (B), a stabilizer (C), and an additive (F). The base polymer (A) comprises polyvinyl chloride resin (a1), chlorinated polyethylene (a2), and urethane thermoplastic elastomer (a3). As a flame retardant, it substantially does not contain metal hydroxides and antimony trioxide. Contains calcined clay (D), The stabilizer (C) contains at least two of the following: hydrotalcite, Ca-Zn-based stabilizer, and metal soap. The additive (F) is contained in an amount of 0.5 to 40 parts by mass per 100 parts by mass of the total amount of components (A) to (D). The additive (F) contains unfired clay, Based on mass, the Al content of the fired clay (D) ２ O ３ SiO content ２ The content is less than 2 (SiO ２ / Al ２ O ３ (Mass ratio) < 2) and the Al of the unfired clay ２ O ３ SiO content ２ The content is 2 or more (SiO ２ / Al ２ O ３ (Mass ratio) ≥ 2) The volume resistivity at 30°C is 5E + 13 Ω·cm or greater. ,cable.

8. A wire comprising a conductor and an insulating layer covering the conductor, The insulating layer is composed of a halogen-containing resin composition comprising a base polymer (A), a plasticizer (B), a stabilizer (C), and an additive (F). The base polymer (A) comprises polyvinyl chloride resin (a1), chlorinated polyethylene (a2), and urethane thermoplastic elastomer (a3). As a flame retardant, it substantially does not contain metal hydroxides and antimony trioxide. Contains calcined clay (D), The stabilizer (C) contains at least two of the following: hydrotalcite, Ca-Zn-based stabilizer, and metal soap. The additive (F) is contained in an amount of 0.5 to 40 parts by mass per 100 parts by mass of the total amount of components (A) to (D). The additive (F) contains unfired clay, Based on mass, the Al content of the fired clay (D) ２ O ３ SiO content ２ The content is less than 2 (SiO ２ / Al ２ O ３ (Mass ratio) < 2) and the Al of the unfired clay ２ O ３ SiO content ２ The content is 2 or more (SiO ２ / Al ２ O ３ (Mass ratio) ≥ 2) The volume resistivity at 30°C is 5E + 13 Ω·cm or greater. Electric wire.

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