JP2018193473A - Soft vinyl chloride resin composition and water-resistant cable using the same - Google Patents

Abstract

To provide a soft vinyl chloride resin composition capable of improving flexibility of a cable in addition to water resistance thereof, and a water-resistant cable.SOLUTION: A soft vinyl chloride resin composition contains a vinyl chloride resin, a methyl methacrylate-butadiene-styrene-copolymer (MBS), a methyl methacrylate-based polymer (MMA-based polymer) and silica particles. Based on 100 pts.mass of the vinyl chloride resin, a content of the MBS is 30-100 pts.mass, a content of the MMA-based polymer is 1-10 pts.mass, and a content of the silica particles is 0.5-6 pts.mass. A content of a plasticizer that is liquid at a normal temperature is 9 pts.mass or less based on 100 pts.mass of the vinyl chloride resin. Water-resistant cables 1 and 1A cover an insulated wire 10 and sheaths 20 and 20A which cover the insulated wire and contain the soft vinyl chloride resin composition.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a soft vinyl chloride resin composition and a water-resistant cable using the same. Specifically, the present invention relates to a soft vinyl chloride resin composition excellent in water resistance and flexibility, and a water resistant cable using the soft vinyl chloride resin composition.

  Conventionally, in order to improve the water resistance of a cable, a water shielding layer is provided between a cable covering material (sheath) and an electric wire insulator covered with the covering material to ensure water shielding. Such a water shielding layer is often formed by laminating metal sheets. By providing the water shielding layer, moisture that has penetrated into the sheath from the outside is prevented from entering the inside of the cable.

  For example, in Patent Document 1, a spacer layer is formed on an outer layer of a cable core including a conductor and an insulator layer, a water shielding tape layer is provided on the spacer layer, and the water shielding tape layer is further covered with a sheath layer made of resin. A water shielding cable is disclosed. Moreover, it discloses that the water shielding tape which forms a water shielding tape layer consists of a metal layer, an adhesive layer, or a metal layer, a reinforcement layer, and an adhesive layer.

JP 2014-75247 A

  However, although the water shielding layer made of a metal sheet is excellent in water shielding properties, it has a problem that the flexibility of the obtained cable becomes insufficient because of poor flexibility. Moreover, since the water shielding layer which consists of metal sheets is hard to cut | disconnect, there exists a problem that the workability of a cable deteriorates.

  The present invention has been made in view of such problems of the prior art. An object of the present invention is to provide a soft vinyl chloride resin composition capable of improving flexibility in addition to the water resistance of the cable, and a water resistant cable using the soft vinyl chloride resin composition. is there.

  The soft vinyl chloride resin composition according to the first aspect of the present invention contains a vinyl chloride resin, a methyl methacrylate-butadiene-styrene copolymer, a methyl methacrylate polymer, and silica particles. The content of methyl methacrylate-butadiene-styrene copolymer is 30 to 100 parts by mass and the content of methyl methacrylate polymer is 1 to 10 parts by mass with respect to 100 parts by mass of the vinyl chloride resin. The content of silica particles is 0.5 to 6 parts by mass. In the soft vinyl chloride resin composition, the content of the plasticizer that is liquid at normal temperature is 9 parts by mass or less with respect to 100 parts by mass of the vinyl chloride resin.

  The soft vinyl chloride resin composition according to the second aspect of the present invention is the soft vinyl chloride resin composition according to the first aspect, wherein the tensile strength specified in JIS K6723 is 10 MPa or more, and the soft vinyl chloride resin composition specified in JIS K6723. Elongation is 120% or more. Furthermore, the durometer hardness defined in JIS K7215 is 82-96.

  The waterproof cable according to the third aspect of the present invention includes one or a plurality of insulated wires including a conductor and an insulator covering the conductor, covers the insulated wires, and relates to the first or second aspect. And a sheath containing a soft vinyl chloride resin composition.

  The water-resistant cable according to the fourth aspect of the present invention is the water-resistant cable according to the third aspect, wherein the sheath covers the inner layer covering the insulated wire, the inner layer, and the soft vinyl chloride resin composition. And a skin layer.

  The water-resistant cable according to the fifth aspect of the present invention is the water-resistant cable according to the fourth aspect, wherein the thickness of the skin layer with respect to the thickness of the entire sheath is 10% or more in the cross section perpendicular to the longitudinal direction of the insulated wire. is there.

  The soft vinyl chloride resin composition of the present invention has low water absorption and good flexibility. Therefore, when a soft vinyl chloride resin composition is used for the sheath of a water-resistant cable, it is possible to ensure water resistance without using a metal water-impervious layer and to further increase flexibility. Moreover, since the metal water-impervious layer is not used, the sheath can be easily cut and the workability of the water-resistant cable can be improved.

It is sectional drawing which shows roughly an example of the water-resistant cable which concerns on embodiment of this invention. It is sectional drawing which shows schematically the other example of the water-resistant cable which concerns on embodiment of this invention.

  Hereinafter, a soft vinyl chloride resin composition according to an embodiment of the present invention and a water-resistant cable using the soft vinyl chloride resin composition will be described in detail with reference to the drawings. In addition, the dimension ratio of drawing is exaggerated on account of description, and may differ from an actual ratio.

[Soft vinyl chloride resin composition]
The soft vinyl chloride resin composition according to this embodiment is mainly composed of a vinyl chloride resin. Vinyl chloride resin is a material that has high heat resistance without being subjected to crosslinking treatment, is excellent in electrical insulation, is inexpensive, and can be easily processed.

  Examples of the vinyl chloride resin used in the soft vinyl chloride resin composition of the present embodiment include polyvinyl chloride, chlorinated polyvinyl chloride, polyvinylidene chloride, chlorinated polyethylene, vinyl chloride-vinyl acetate copolymer, vinyl chloride. -Ethylene copolymer, vinyl chloride-propylene copolymer, vinyl chloride-styrene copolymer, vinyl chloride-isobutylene copolymer, vinyl chloride-vinylidene chloride copolymer, vinyl chloride-styrene-maleic anhydride copolymer , Vinyl chloride-styrene-acrylonitrile copolymer, vinyl chloride-butadiene copolymer, vinyl chloride-isoprene copolymer, vinyl chloride-chlorinated propylene copolymer, vinyl chloride-vinylidene chloride-vinyl acetate copolymer, chloride Vinyl-maleic acid ester copolymer, vinyl chloride-methacrylic acid ester copolymer Body, vinyl chloride - acrylonitrile copolymer, vinyl chloride - may be mentioned various vinyl ether copolymers. These vinyl chloride resins may be used individually by 1 type, and may be used in combination of 2 or more type. The polymerization method of the vinyl chloride resin is not particularly limited, such as bulk polymerization, solution polymerization, suspension polymerization, and emulsion polymerization.

  The average degree of polymerization (weight average degree of polymerization) of the vinyl chloride resin is not particularly limited, but is preferably 500 to 5000, more preferably 1000 to 3000. When the average degree of polymerization is 500 or more, a decrease in wear resistance of the soft vinyl chloride resin composition can be suppressed. Further, when the average polymerization degree is 5000 or less, when extruding a soft vinyl chloride resin composition, it is possible to suppress an increase in melt viscosity during extrusion molding and to further prevent deterioration of kneading and molding processability. it can. In addition, in the soft vinyl chloride resin composition of this embodiment, you may use the vinyl chloride resin in the range of the said polymerization degree 1 type or in combination of 2 or more types.

  Usually, since a vinyl chloride resin has high hardness, in order to provide a softness | flexibility, the plasticizer is added. As a plasticizer used for the vinyl chloride resin, a plasticizer that is liquid at room temperature (5-35 ° C.) is generally used. Examples of such plasticizers that are liquid at room temperature include trimellitic acid plasticizers, pyromellitic acid plasticizers, phthalic acid plasticizers, aliphatic dibasic acid plasticizers, epoxy plasticizers, and phosphoric acid. Examples include ester plasticizers, polyester plasticizers, and ether ester plasticizers. However, when a plasticizer that is liquid at room temperature is used with respect to the vinyl chloride resin, water easily enters the resulting resin composition, and the water resistance of the resin composition is reduced. Therefore, when a resin composition is used for the sheath of an electric wire or a cable, water resistance and durability over a long period of time may not be ensured.

  In order to impart flexibility to the vinyl chloride resin, an ethylene-vinyl acetate copolymer (EVA) may be used. The ethylene-vinyl acetate copolymer has vinyl acetate units in the molecule. And the softness | flexibility of a resin composition improves because the vinyl acetate unit in an ethylene-vinyl acetate copolymer increases. However, it is difficult to uniformly mix the ethylene-vinyl acetate copolymer with the vinyl chloride resin as compared with the liquid plasticizer. Moreover, even if an ethylene-vinyl acetate copolymer is added, there is a problem that the hardness of the resulting vinyl chloride resin composition is hardly lowered.

  Therefore, the soft vinyl chloride resin composition is obtained by adding methyl methacrylate-butadiene-styrene copolymer (MBS), methyl methacrylate polymer (MMA polymer), and silica particles to vinyl chloride resin. ing. The methyl methacrylate-butadiene-styrene copolymer has high rubber elasticity at normal temperature and low temperature. Therefore, by mixing the vinyl chloride resin and MBS, it becomes possible to impart flexibility and elasticity to the resin composition. The methyl methacrylate polymer can create a pseudo-crosslinked state by the long chain of the methyl methacrylate polymer entangled with the vinyl chloride resin molecule. Therefore, the gelatinization of the vinyl chloride resin can be promoted and workability can be improved. Furthermore, the methyl methacrylate polymer can impart melt elasticity to the resulting resin composition and increase the melt tension. Therefore, MBS can be highly dispersed by the combined use of methyl methacrylate polymer and MBS. Further, by adding silica particles, the rigidity and heat resistance of the soft vinyl chloride resin composition can be increased, and it can be suitably used as a sheath of a cable described later.

  As the methyl methacrylate polymer, a copolymer of methyl methacrylate and a monomer copolymerizable with the methyl methacrylate can be used. As a monomer copolymerizable with methyl methacrylate, for example, a (meth) acrylic acid alkyl ester having an alkyl group having 1 to 10 carbon atoms is preferred. Specifically, monomers copolymerizable with methyl methacrylate include ethyl methacrylate, butyl methacrylate, cyclohexyl methacrylate, benzyl methacrylate, glycidyl methacrylate, epoxycyclohexylmethyl methacrylate, 2-hydroxyethyl methacrylate, Methacrylic acid esters such as 2-hydroxypropyl methacrylate; methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, glycidyl acrylate, epoxycyclohexylmethyl acrylate, 2-hydroxyethyl acrylate, acrylic acid Acrylic esters such as 2-hydroxypropyl; carboxylic acids such as methacrylic acid and acrylic acid and esters thereof; vinyl shear such as acrylonitrile and methacrylonitrile Vinylenes such as styrene, α-methylstyrene, monochlorostyrene, dichlorostyrene; maleic acid, fumaric acid and esters thereof; vinyl halides such as vinyl chloride, vinyl bromide and chloroprene; vinyl acetate; ethylene Alkenes such as propylene, butylene, butadiene, isobutylene; halogenated alkenes; allyl methacrylate, diallyl phthalate, triallyl cyanurate, monoethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate, divinylbenzene, etc. These multifunctional monomers are mentioned. These vinyl monomers may be used individually by 1 type, and may be used in combination of 2 or more type.

The silica particles are not particularly limited as long as they can increase the rigidity and heat resistance of the soft vinyl chloride resin composition. As the silica particles, for example, at least one of fine particle silica and fumed silica can be used. Further, the silica particles preferably comprise at least one of silicon dioxide (SiO ₂₎ and silicates. As the silicate, at least one selected from the group consisting of talc, clay, mica, asbestos, bentonite, sepiolite, calcium silicate, aluminum silicate, and montmorillonite can be used. Moreover, you may modify the surface of a silica particle to hydrophilicity or hydrophobicity using a silane coupling agent.

  The particle diameter of the silica particles is not particularly limited, but from the viewpoint of enhancing dispersibility, the average particle diameter (median diameter (D50)) of the silica particles is preferably 10 nm to 1 μm. In addition, the average particle diameter of a silica particle can be calculated | required with the laser diffraction type particle size distribution measuring apparatus.

  In the soft vinyl chloride resin composition of the present embodiment, the content of methyl methacrylate-butadiene-styrene copolymer (MBS) is preferably 30 to 100 parts by mass with respect to 100 parts by mass of the vinyl chloride resin. When the content of MBS is less than 30 parts by mass, the flexibility of the soft vinyl chloride resin composition becomes insufficient, and the flexibility of the sheath may be reduced. On the other hand, if the MBS content exceeds 100 parts by mass, the water absorption of the soft vinyl chloride resin composition is increased, which may reduce the water resistance of the sheath.

  In the soft vinyl chloride resin composition, the content of methyl methacrylate polymer (MMA polymer) is 1 to 10 parts by mass with respect to 100 parts by mass of vinyl chloride resin, and the content of silica particles is 0.5. It is preferably ˜6 parts by mass. When the content of the MMA-based polymer and silica particles is within this range, it is possible to increase the tensile strength and hardness and improve the durability while reducing the water absorption of the resin composition.

  Here, as described above, when a plasticizer that is liquid at room temperature is used, the water absorption is increased in addition to the flexibility of the vinyl chloride resin composition, so that the water resistance of the resin composition is lowered. Therefore, it is preferable that the soft vinyl chloride resin composition of this embodiment does not contain a liquid plasticizer as much as possible. In the soft vinyl chloride resin composition, the content of the plasticizer that is liquid at room temperature is preferably 9 parts by mass or less, more preferably 5 parts by mass or less, with respect to 100 parts by mass of the vinyl chloride resin. More preferably, it is at most parts. In addition, it is especially preferable that a soft vinyl chloride resin composition does not contain a liquid plasticizer. However, a small amount of a liquid plasticizer may be contained as long as it does not affect the water resistance of the soft vinyl chloride resin composition.

  Similarly, when an ethylene-vinyl acetate copolymer (EVA) is used, the flexibility of the vinyl chloride resin composition increases, but the processability decreases. Therefore, it is preferable that the soft vinyl chloride resin composition of this embodiment does not contain EVA as much as possible. In the soft vinyl chloride resin composition, the EVA content is preferably 9 parts by mass or less, more preferably 5 parts by mass or less, and more preferably 3 parts by mass or less with respect to 100 parts by mass of the vinyl chloride resin. Is more preferable. In addition, it is especially preferable that a soft vinyl chloride resin composition does not contain EVA. However, a small amount of EVA may be contained as long as it does not affect the water resistance of the soft vinyl chloride resin composition.

  The soft vinyl chloride resin composition of the present embodiment can contain various additives in addition to the above materials. Additives include stabilizers, lubricants, fillers, flame retardants, pigments, antioxidants, extenders, metal deactivators, anti-aging agents, reinforcing agents, UV absorbers, dyes, colorants, antistatic agents, A foaming agent etc. are mentioned.

  The soft vinyl chloride resin composition of the present embodiment has a tensile strength defined in Japanese Industrial Standard JIS K6723 of 10 MPa or more, an elongation defined in JIS K6723 of 120% or more, and a durometer hardness defined in JIS K7215. Is preferably 82-96. When the tensile strength, elongation, and durometer hardness are within these ranges, when used as a cable sheath, in addition to flexibility, the strength required for the sheath can be secured.

  Next, the manufacturing method of the soft vinyl chloride resin composition of this embodiment is demonstrated. The soft vinyl chloride resin composition is prepared by heating and kneading the above materials, and known methods can be used for the method. For example, a soft vinyl chloride resin composition can be obtained by kneading the above materials using a known kneader such as a Banbury mixer, a pressure kneader, a kneading extruder, a twin screw extruder, or a roll mill. Alternatively, the above materials may be dry blended in advance using a tumbler or the like and then kneaded using the above kneader. Thus, the soft vinyl chloride resin composition of this embodiment can be obtained by heat-kneading.

  The soft vinyl chloride resin composition of the present embodiment does not need to be subjected to a crosslinking step such as electron beam irradiation or radiation irradiation to crosslink the vinyl chloride resin, MBS, or MMA polymer. That is, the soft vinyl chloride resin composition can be prepared by kneading a vinyl chloride resin, MBS, an MMA polymer, silica particles, and an additive to be added as necessary. Therefore, it becomes possible to easily obtain a soft vinyl chloride resin composition by a simple process.

  Thus, the soft vinyl chloride resin composition according to the present embodiment contains a vinyl chloride resin, a methyl methacrylate-butadiene-styrene copolymer, a methyl methacrylate polymer, and silica particles. The content of methyl methacrylate-butadiene-styrene copolymer is 30 to 100 parts by mass and the content of methyl methacrylate polymer is 1 to 10 parts by mass with respect to 100 parts by mass of the vinyl chloride resin. The content of silica particles is 0.5 to 6 parts by mass. And content of the plasticizer which is liquid at normal temperature is 9 mass parts or less with respect to 100 mass parts of vinyl chloride resins. Since the soft vinyl chloride resin composition of this embodiment contains MBS, it becomes possible to increase flexibility. Further, by containing MMA polymer and silica particles, the strength of the soft vinyl chloride resin composition can be increased, and it can be suitably used as a sheath of a cable. In addition, since the soft vinyl chloride resin composition reduces the addition amount of the plasticizer that is liquid at room temperature as much as possible, it is possible to suppress water absorption and increase water resistance.

[Waterproof cable]
Next, the water resistant cable according to the present embodiment will be described. As shown in FIG. 1, the water-resistant cable 1 includes a plurality of bundled insulated wires 10 and a sheath 20 as a covering material that covers the peripheral edges of the bundled insulated wires 10. In addition, the water-resistant cable 1 does not necessarily have to bundle a plurality of insulated wires 10 and may be one in which a single insulated wire 10 is covered with a sheath 20.

  The insulated wire 10 includes a conductor 11 and an insulator 12 that covers the conductor 11. As the conductor 11, a single wire constituted by one strand may be used, or a stranded wire conductor constituted by twisting a plurality of strands may be used. A stranded conductor is also a concentric stranded wire in which one or several strands are centered and the strands are concentrically twisted around it; a collective stranded wire in which a plurality of strands are twisted together in the same direction Any of the composite strands in which a plurality of aggregate strands are twisted concentrically can be used. The diameter of the conductor 11 and the diameter of each strand constituting the stranded conductor are not particularly limited. Furthermore, the materials of the conductor 11 and the stranded wire conductor are not particularly limited, and for example, known conductive metal materials such as copper, copper alloy, aluminum, and aluminum alloy can be used. Moreover, the surface of the conductor 11 and the strand wire conductor may be plated, for example, tin plating, silver plating, or nickel plating may be applied.

  The insulator 12 that covers the outer periphery of the insulated wire 10 is not particularly limited in material and thickness as long as electrical insulation with respect to the conductor 11 can be secured. As the insulator 12, an olefin resin such as cross-linked polyethylene or polypropylene, or an electrically insulating resin such as vinyl chloride can be arbitrarily used. Specifically, as the resin material constituting the insulator 12, for example, vinyl chloride, heat-resistant vinyl chloride, crosslinked vinyl chloride, polyethylene, crosslinked polyethylene, expanded polyethylene, crosslinked expanded polyethylene, chlorinated polyethylene, polypropylene, polyamide (nylon) ), Polyvinylidene fluoride, ethylene-tetrafluoroethylene copolymer, ethylene tetrafluoride-hexafluoropropylene copolymer, tetrafluoroethylene, perfluoroalkoxyalkane, natural rubber, chloroprene rubber, butyl rubber, ethylene propylene rubber Chlorosulfonated polyethylene rubber and silicone rubber can be used. These materials may be used individually by 1 type, and may be used in combination of 2 or more types.

  In the water resistant cable 1 of the present embodiment, the sheath 20 covering the periphery of the insulated wire 10 preferably contains the above-mentioned soft vinyl chloride resin composition, and the sheath 20 is more preferably made of the soft vinyl chloride resin composition. preferable. As described above, the soft vinyl chloride resin composition of the present embodiment can be suitably used as the sheath 20 because it has flexibility and high water resistance and strength.

  Here, the water-resistant cable 1 does not need to use a metal water-proof layer used in the water-proof cable of Patent Document 1. That is, as shown in FIG. 1, a metal water shielding layer is not provided between the insulated wire 10 and the sheath 20, and the surface of the insulated wire 10 and the inner surface of the sheath 20 are in direct contact with each other. ing. As described above, since the soft vinyl chloride resin composition of the present embodiment has high water barrier properties, the water resistance of the water resistant cable 1 can be increased without using a metal water barrier layer. Moreover, since the water-resistant cable 1 does not use a metal water-impervious layer, the flexibility can be enhanced. Furthermore, since the metal water-impervious layer is not used, the sheath 20 can be easily cut and the workability of the water-resistant cable 1 can be improved.

  The sheath 20 in the water-resistant cable 1 can be produced by a known method, for example, can be produced by a general extrusion molding method. Specifically, the sheath 20 can be formed by bundling one or a plurality of insulated wires 10 and then extruding and covering the outside with a soft vinyl chloride resin composition.

  In the water resistant cable 1 of the present embodiment, the sheath 20 may be a single layer, as shown in FIG. That is, the sheath 20 may be a single-layer coating material made of a soft vinyl chloride resin composition. However, the sheath 20 is not limited to such a single layer structure, and may be a multilayer structure formed by laminating a plurality of resin layers having different constituent materials, for example.

  Specifically, as shown in FIG. 2, the sheath 20 </ b> A may have a multilayer structure including an inner layer 21 that covers the insulated wire 10 and a skin layer 22 that covers the inner layer 21. And it is preferable that the skin layer 22 contains the above-mentioned soft vinyl chloride resin composition, and it is more preferable to consist of a soft vinyl chloride resin composition. As described above, since the soft vinyl chloride resin composition of the present embodiment has flexibility and high water resistance and strength, it can be suitably used as the outermost skin layer 22. In addition, although the constituent material of the inner layer 21 is not specifically limited, For example, the material of the above-mentioned insulator 12 can be used.

  2, in the cross section perpendicular to the longitudinal direction of the insulated wire 10, the thickness t2 of the skin layer 22 with respect to the thickness t1 of the entire sheath 20A is preferably 10% or more. When the thickness t2 of the skin layer 22 is 10% or more of the thickness t1 of the entire sheath 20A, it is possible to ensure the water resistance and strength necessary for the skin layer 22.

  As described above, the water-resistant cable 1, 1A of the present embodiment includes one or a plurality of insulated wires 10 including the conductor 11 and the insulator 12 that covers the conductor 11, and the insulated wire 10, and is made of soft vinyl chloride. And sheaths 20 and 20A containing a resin composition. The sheath 20A may have an inner layer 21 that covers the insulated wire 10 and a skin layer 22 that covers the inner layer 21 and contains a soft vinyl chloride resin composition. Since the soft vinyl chloride resin composition of the present embodiment has high water resistance and strength while having flexibility, when it is used as the sheath 20 or 20A, it is water resistant that has both water resistance and flexibility. Cable 1 and 1A can be obtained.

  In addition, although the example which used the soft vinyl chloride resin composition for sheath 20 and 20A was demonstrated in FIG.1 and FIG.2, this embodiment is not limited to such an aspect. Since the soft vinyl chloride resin composition of this embodiment also has electrical insulation, it may be used as the insulator 12 in the insulated wire 10.

  EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention further in detail, this invention is not limited to these Examples.

  First, using a kneader, the following vinyl chloride resin, methyl methacrylate-butadiene-styrene copolymer (MBS), methyl methacrylate polymer (MMA polymer), silica particles, stabilizer, and plasticizer were added. Melt kneading was carried out at the blending amounts shown in Tables 1 and 2. Thereby, the resin composition of each Example and the comparative example was prepared.

Vinyl chloride resin: manufactured by Taiyo PVC Co., Ltd., TH PVC homopolymer TH-1300
-Methyl methacrylate-butadiene-styrene copolymer (MBS): manufactured by Mitsubishi Chemical Corporation, resin modifier Metabrene (registered trademark) C-223A
MMA polymer: Mitsubishi Chemical Corporation, resin modifier Methbrene (registered trademark) P-530A (butyl acrylate-methyl methacrylate copolymer)
Silica particles: Nippon Aerosil Co., Ltd., AEROSIL (registered trademark) R972 (hydrophobic fumed silica)
・ Stabilizer: Calcium-zinc stabilizer ・ Liquid plasticizer: DINP (Diisononyl phthalate), manufactured by J. Plus

[Evaluation]
About the resin composition of Examples 1-8 and Comparative Examples 1-3, tensile strength, elongation, and durometer hardness were measured. Specifically, the tensile strength and elongation were performed in accordance with the 6.3 tensile test of Japanese Industrial Standard JIS K6723 (soft polyvinyl chloride compound). The durometer hardness was measured according to JIS K7215 (plastic durometer hardness test method). In the durometer hardness test, a JIS A hardness meter was used as the durometer, the test temperature was 23 ± 2 ° C., and the load holding time was 10 seconds. Tables 1 and 2 show the measurement results of tensile strength, elongation and durometer hardness in the resin compositions of the respective examples.

Furthermore, water absorption was evaluated about the resin composition of Examples 1-8 and Comparative Examples 1-3. Specifically, the resin compositions of Examples 1 to 8 and Comparative Examples 1 to 3 were molded to produce plate-shaped test pieces having a length of 20 mm, a width of 20 mm, and a thickness of 1 mm. And the mass before the immersion to a pure water was measured regarding the test piece which consists of a resin composition of each case. Next, the test piece was immersed in pure water at 70 ° C. and held for 360 hours. And the mass of the test piece after being immersed in a pure water was measured, and the water absorption was calculated | required from the following formula.
[Equation 1]
Water absorption (%) = [(mass of test piece after immersion) − (mass of test piece before immersion)] / [mass of test piece before immersion] × 100

  The case where the water absorption rate of the test piece was 0.5% or less was evaluated as “◯”, and the case where the water absorption rate exceeded 0.5% was evaluated as “x”. The evaluation results of water absorption in each resin composition are shown together in Tables 1 and 2.

  As shown in Table 1, in the resin compositions of Examples 1 to 8, the tensile strength was 10 MPa or more, the elongation was 120% or more, the durometer hardness was 82 to 96, and the water absorption was 0.5%. It turns out that it becomes the following. That is, with respect to 100 parts by mass of vinyl chloride resin, MBS is 30 to 100 parts by mass, MMA polymer is 1 to 10 parts by mass, silica particles are 0.5 to 6 parts by mass, When the agent is not included, it is understood that the strength, flexibility and water resistance are excellent.

  In contrast, as shown in Comparative Example 1, when MBS is less than 30 parts by mass with respect to 100 parts by mass of the vinyl chloride resin, it can be seen that the durometer hardness is increased and the flexibility is deteriorated. Furthermore, as shown in Comparative Example 2, it is understood that when MBS exceeds 100 parts by mass with respect to 100 parts by mass of the vinyl chloride resin, the water absorption rate is increased and the water resistance is deteriorated. Moreover, as shown in Comparative Example 3, MBS is 30 to 100 parts by mass, MMA polymer is 1 to 10 parts by mass, and silica particles are in the range of 0.5 to 6 parts by mass. When the liquid plasticizer is included, the water absorption rate is increased and the water resistance is deteriorated.

  Although the present invention has been described with reference to the examples and comparative examples, the present invention is not limited to these, and various modifications can be made within the scope of the gist of the present invention.

DESCRIPTION OF SYMBOLS 1,1A Water resistant cable 10 Insulated electric wire 11 Conductor 12 Insulator 20, 20A Sheath 21 Inner layer 22 Skin layer

Claims (5)

Containing a vinyl chloride resin, a methyl methacrylate-butadiene-styrene copolymer, a methyl methacrylate polymer, and silica particles;
The content of methyl methacrylate-butadiene-styrene copolymer is 30 to 100 parts by mass and the content of methyl methacrylate polymer is 1 to 10 parts by mass with respect to 100 parts by mass of the vinyl chloride resin. The content of silica particles is 0.5 to 6 parts by mass,
The soft vinyl chloride resin composition whose content of the plasticizer which is liquid at normal temperature is 9 parts by mass or less with respect to 100 parts by mass of the vinyl chloride resin.   The soft chloride according to claim 1, wherein the tensile strength specified in JIS K6723 is 10 MPa or more, the elongation specified in JIS K6723 is 120% or more, and the durometer hardness specified in JIS K7215 is 82-96. Vinyl resin composition. One or more insulated wires comprising a conductor and an insulator covering the conductor; and
A sheath that covers the insulated wire and includes the soft vinyl chloride resin composition according to claim 1 or 2,
A water-resistant cable.   The water-resistant cable according to claim 3, wherein the sheath has an inner layer that covers the insulated wire, and a skin layer that covers the inner layer and includes the soft vinyl chloride resin composition.   The waterproof cable according to claim 4, wherein the thickness of the skin layer is 10% or more with respect to the thickness of the entire sheath in a cross section perpendicular to the longitudinal direction of the insulated wire.

Images