JP2018085309A - Production method for polyolefin foam-covered wire and cable and polyolefin foam-covered wire and cable - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a production method for polyolefin foam-covered wire and cable having an improved tearing property or a peeling property and excellent workability and sufficient mechanical characteristics in combination.SOLUTION: A production method for polyolefin foam-covered wire and cable including : (1) a step of mixing at least base resin containing olefin-based resin, a crosslinking agent, a crosslinking aide, and a foaming agent to prepare a polyolefin-based foamable resin composition; (2) a step of crosslinking the polyolefin-based foamable resin composition prepared in the step (1) to obtain a crosslinked body of the polyolefin-based foamable resin composition; (3) a step of extruding the crosslinked body obtained in the step (2) to form a covered layer made of the crosslinked body in an outer periphery of a conductor; and (4) a step of foaming the covered layer formed in the step (3).SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method for producing a foamed polyolefin-coated wire / cable and a foamed polyolefin-coated wire / cable.

  In recent years, interest in environmental problems has increased worldwide, and electric wires and cables using non-halogen compositions that do not generate harmful halogen gas during incineration are becoming widespread. Various proposals have been made for electric wires and cables using non-halogen compositions.

Non-halogen compositions used for electric wires and cables include polyolefin resins.
Therefore, in recent years, non-halogen flame retardant resin compositions in which a metal hydroxide is blended with a polyolefin resin as a flame retardant have been frequently used.

  For example, in the following Patent Document 1, ethylene / acrylic acid ester copolymer (a) and / or ethylene / vinyl acetate copolymer (b) 20 to 80% by mass, acrylic rubber (c) 10 to 40% by mass, And 20% by mass or less of polyethylene (e) and / or a styrene block copolymer modified with an unsaturated carboxylic acid or a derivative thereof, if necessary. (F) The conductor is a crosslinked product of a composition containing 150 to 250 parts by mass of a metal hydrate (g) surface-treated with a silane coupling agent with respect to 100 parts by mass of the resin mixture containing 20% by mass or less. Coated insulated wires have been proposed.

JP 2001-325833 A

  However, in the conventional technology as described above, it is necessary to add a large amount of a metal hydrate such as magnesium hydroxide in order to obtain the desired sufficient flame retardancy, and the resin component becomes hard, and the wire / cable There is a problem that the ease of tearing and the peelability are deteriorated and the workability is inferior.

  The present invention has been made in view of the above-described circumstances, and its purpose is to improve the ease of tearing and peelability, and to provide a foamed polyolefin-coated electric wire having excellent workability and sufficient mechanical properties. The object is to provide a cable manufacturing method and a foamed polyolefin-coated electric wire / cable.

In order to achieve the above-mentioned object, the “method for producing a foamed polyolefin-coated wire / cable” according to the present invention is characterized by the following [1] to [3].
[1]
(1) Step of preparing a polyolefin-based foamable resin composition by mixing at least a base resin containing a polyolefin-based resin, a crosslinking agent, a crosslinking aid, and a foaming agent (2) Polyolefin prepared in the step (1) Step (3) for obtaining a cross-linked product of a polyolefin-based foamable resin composition by cross-linking a foamed resin composition and extruding the cross-linked product obtained in the step (2) and coating the outer periphery of the conductor with the cross-linked product. Step for forming layer (4) A method for producing a foamed polyolefin-coated electric wire / cable including the step of foaming the coating layer formed in step (3).
[2]
In the method for producing a foamed polyolefin-coated electric wire / cable described in [1] above,
Containing 0.02 to 0.5 parts by weight of the crosslinking agent with respect to 100 parts by weight of the base resin;
Containing 1 to 3 times the crosslinking agent,
The manufacturing method for foamed polyolefin-coated wires and cables.
[3]
In the method for producing a foamed polyolefin-coated electric wire / cable described in [2] above,
The base resin contains 60 to 95 parts by weight of the polyolefin resin and 5 to 40 parts by weight of a rubber component,
The content of the foaming agent is 0.1 to 10 parts by weight,
The polyolefin-based foamable resin composition further contains 10 to 90 parts by weight of a filler,
Containing 0.5 to 10 parts by weight of a lubricant;
The manufacturing method for foamed polyolefin-coated wires and cables.

  According to the method for producing a foamed polyolefin-coated electric wire / cable having the above-described configuration [1], the polyolefin-based foamable resin composition is crosslinked before the coating layer is formed on the outer periphery of the conductor. Therefore, foaming is stabilized, high foaming is realized, and ease of tearing and peelability are improved. In addition, sufficient mechanical properties such as high tensile strength and resistance to heat deformation can be obtained.

  Therefore, the manufacturing method of the foamed polyolefin-coated electric wire / cable of this configuration can achieve both excellent workability and mechanical characteristics.

  According to the method for producing a foamed polyolefin-coated electric wire / cable having the above-mentioned configuration [2], since the blending amount of the crosslinking agent and the crosslinking aid is specified, it is good for the polyolefin-based foamable resin composition after crosslinking. Can provide excellent extrusion characteristics.

  Therefore, excellent workability and mechanical characteristics of the electric wire / cable can be obtained, and the manufacturability is also improved.

  According to the method for producing a foamed polyolefin-coated wire / cable having the above-mentioned configuration [3], the composition of the base resin in the polyolefin-based foamable resin composition, its content, the content of the foaming agent, the content of the filler, and the lubricant Since the content of is specified, stabilization of foaming, ease of tearing, peelability, and mechanical properties can be further enhanced.

  Therefore, the workability and mechanical characteristics of the electric wire / cable can be further improved.

Furthermore, in order to achieve the above-mentioned object, the “foamed polyolefin-coated wire / cable” according to the present invention is characterized by the following [4].
[4]
A foamed polyolefin-coated electric wire / cable having a conductor and a coating layer that is foamed and contains a polyolefin-based resin on the outer periphery of the conductor,
The foaming rate of the coating layer is 3 to 30%,
The radial orientation of the polyolefin resin cross-linked product in the coating layer is larger than the axial orientation,
It must be a foamed polyolefin-coated wire / cable.

  According to the foamed polyolefin-coated electric wire / cable having the configuration of [4] above, the foaming rate of the coating layer and the orientation direction of the cross-linked polyolefin resin are specified, so that foaming is stabilized and high foaming is realized. , Ease of tearing and peelability are improved. Moreover, sufficient tensile strength and mechanical properties such as heat deformation can be obtained.

  Therefore, the foamed polyolefin-coated electric wire / cable of this configuration can achieve both excellent workability and mechanical characteristics.

  ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the foaming polyolefin covering electric wire and cable which improved the easiness of tearing and peelability, had the outstanding workability, and also had sufficient mechanical characteristics, and the foam manufactured by this manufacturing method A polyolefin-coated wire / cable can be provided.

  The present invention has been briefly described above. Further, the details of the present invention will be further clarified by reading through a mode for carrying out the invention described below (hereinafter referred to as “embodiment”) with reference to the accompanying drawings. .

FIG. 1 is a cross-sectional view of a foamed polyolefin-coated electric wire / cable according to the present embodiment, (a) is a cross-sectional view of the foamed polyolefin-coated electric wire, and (b) is a cross-sectional view of the foamed polyolefin-coated cable. FIG. 2 is a cross-sectional view of another example of the foamed polyolefin-coated wire according to this embodiment.

  Hereinafter, an embodiment of a method for producing a foamed polyolefin-coated wire / cable and a foamed polyolefin-coated wire / cable according to the present invention will be described with reference to the drawings.

FIG. 1 is a cross-sectional view of a foamed polyolefin-coated electric wire / cable according to the present embodiment, (a) is a cross-sectional view of the foamed polyolefin-coated electric wire, and (b) is a cross-sectional view of the foamed polyolefin-coated cable.
As shown in FIG. 1A, the electric wire 1 in this embodiment includes a conductor 2 such as a copper wire, an insulator 3 that covers the outer periphery of the conductor 2, and a coating layer 4 that covers the outer periphery of the insulator 3. Is provided.
As shown in FIG. 1B, the foamed polyolefin-coated cable 10 according to this embodiment includes a plurality of bundled electric wires 1 (1a, 1b, 1c) and peripheral edges of the plurality of bundled wires 1. And a covering layer 4 as a covering layer.
FIG. 2 is a cross-sectional view of another example of the foamed polyolefin-coated wire according to this embodiment. The electric wire 1 ′ in the present embodiment includes a conductor 2 such as a copper wire, an insulator 3 that covers the outer periphery of the conductor 2, and a coating layer 4 that covers the outer periphery of the insulator 3. And the upper layer 42.

  The conductor 2 may be only one strand or may be formed by bundling a plurality of strands. As a material of the conductor 2, for example, conductive metal such as copper, plated copper, copper alloy, aluminum, and aluminum alloy can be used.

  The insulator 3 can be provided as desired, and the material thereof is not particularly limited, and can be appropriately selected from known insulators. For example, those made of polyethylene, cross-linked polyethylene, and a vinyl mixture are preferably used. It is done.

  As described above, the coating layer 4 is produced by producing a polyolefin-based foamable resin composition, cross-linking the produced polyolefin-based foamable resin composition, and extruding the obtained cross-linked body, on the outer periphery of the conductor 2 or insulating. When the body 3 is provided, it is formed by forming a coating layer made of the crosslinked body on the outer periphery and foaming the coating layer. This will be described below.

  The polyolefin-based foamable resin composition contains a base resin containing a polyolefin-based resin, a crosslinking agent, a crosslinking aid, and a foaming agent.

The polyolefin resin is not particularly limited, and examples thereof include high density polyethylene (HDPE), medium density polyethylene (MDPE), low density polyethylene (LDPE), linear low density polyethylene (L-LDPE), and ultra low density polyethylene. Polyethylene (PE) such as (V-LDPE), polypropylene (PP), ethylene-propylene copolymer (EPR), ethylene-vinyl acetate copolymer (EVA), ethylene-methyl acrylate copolymer (EMA), and An ethylene-ethyl acrylate copolymer (EEA) etc. are mentioned. These polyolefin resins may be used alone or in combination of two or more.
Polyolefin resin is preferably a density of ^{0.85~1.00g / cm 3, 0.90~0.97g / cm} 3 is more preferable. By using a polyolefin-based resin having a density in the above range, the mechanical properties can be further improved. The polyolefin resin preferably has a melt viscosity (MFR) of 0.4 to 2.5, and more preferably 0.4 to 1.0. When the melting temperature of the polyolefin resin is within the above range, the extrusion processability is improved.
In addition, the density as used in the field of this invention is a value measured based on JISK7112, and MFR is a value measured based on JISK7210 at 190 degreeC and a 2.16kgf load.

In addition, as base resin, unless the effect of this invention is impaired, components other than the said polyolefin-type resin can be used suitably as needed. Examples of such components include rubber components, such as ethylene / propylene / non-conjugated diene copolymer rubber (EPDM), styrene / ethylene / butylene / styrene copolymer (SEBS), styrene / butadiene / rubber (SBR). ), Butadiene rubber (BR), nitrile rubber (NBR), and the like.
The blending amount of the rubber component is preferably such that the polyolefin resin is 60 to 95 parts by weight and the rubber component is 5 to 40 parts by weight when the entire base resin is 100 parts by weight. More preferably, the polyolefin resin is 70 to 95 parts by weight and the rubber component is 5 to 40 parts by weight.
The rubber component has a role of imparting rubber elasticity to the resin composition.
When the polyolefin resin is 60 parts by weight or more, the tensile strength is improved, and when it is 95 parts by weight or less, the ease of tearing and the peelability are improved.
When the rubber component is 5 parts by weight or more, the ease of tearing and the peelability are improved, and when it is 40 parts by weight or less, the tensile strength is improved.
In addition, when using polypropylene (PP) as polyolefin resin, it is preferable that the compounding quantity is 30 weight part or less when the whole base resin is 100 weight part. If it exceeds 30 parts by weight, the ease of tearing and the peelability may be reduced.

Examples of the crosslinking agent include organic oxides, but are not limited thereto. Specifically, as the crosslinking agent, dicumyl peroxide (DCP), di-tert-butyl peroxide, 2,5-dimethyl-2,5-di- (tert-butylperoxy) hexane, 2,5 -Dimethyl-2,5-di- (tert-butylperoxy) hexyne-3, 1,3-bis (tert-butylperoxyisopropyl) benzene, 1,1-bis (tert-butylperoxy) -3, 3,5-trimethylcyclohexane, n-butyl-4,4-bis (tert-butylperoxy) valerate, benzoyl peroxide, 2,4-dichlorobenzoyl peroxide, tert-butylperoxybenzoate, tert-butylperoxy Isopropyl carbonate, diacetyl peroxide, lauroyl peroxide, Beauty tert- butyl cumyl peroxide, and the like. These can be used individually by 1 type or in combination of 2 or more types.
Among them, 2,5-dimethyl-2,5-di- (tert-butylperoxy) hexane is a preferable crosslinking agent.

Although it does not restrict | limit especially as a crosslinking adjuvant, For example, the compound which has two or more double bonds in a molecule | numerator is mentioned, Specifically, 1, 4- butanediol diacrylate, 1, 6- hexanediol diacrylate, Diacrylates such as neopentyl glycol diacrylate, diethylene glycol diacrylate, tetraethylene glycol diacrylate, polyethylene glycol diacrylate, tripropylene glycol diacrylate, and polypropylene glycol diacrylate; 1,3-butanediol dimethacrylate, 1,6- Hexanediol dimethacrylate, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, and polyethylene glycol dimethyl Dimethacrylates such as acrylate; triacrylates such as trimethylolpropane triacrylate, tetramethylolmethane triacrylate, and pentaerythritol triacrylate; trimethacrylates such as trimethylolpropane trimethacrylate, and trimethylolethane trimethacrylate; pentaerythritol tetraacrylate, And tetraacrylates such as tetramethylolmethane tetraacrylate; divinyl aromatic compounds such as divinylbenzene; cyanurates such as triallyl cyanurate and triallyl isocyanurate; diallyl compounds such as diallyl phthalate; triallyl compounds and the like.
Among these, a preferred crosslinking aid is triethylene glycol dimethacrylate.

According to the present invention, by providing a quantitative balance between the crosslinking agent and the crosslinking aid, it is possible to provide good extrusion characteristics even after the polyolefin-based foamable resin composition has been crosslinked.
That is, the blending amount of the cross-linking agent is preferably 0.02 to 0.5 parts by weight, more preferably 0.02 to 0.1 parts by weight with respect to 100 parts by weight of the base resin. When the compounding amount of the crosslinking agent is 0.02 part by weight or more, it can provide good extrusion characteristics and improve the tensile strength, and when it is 0.5 part by weight or less, it can provide good extrusion characteristics. The appearance after extrusion is also improved.
Moreover, the amount of the crosslinking aid is preferably 1 to 3 times, more preferably 1.5 to 2.0 times the amount of the crosslinking agent. When the blending amount of the crosslinking aid is 1 or more times that of the crosslinking agent, good extrusion characteristics can be provided and the appearance after extrusion is improved. When the amount is 3 times or less, good extrusion characteristics can be provided and tensile strength is improved.

As the foaming agent, a known chemical decomposition type foaming agent that generates carbon dioxide gas, nitrogen gas or the like by chemical decomposition can be used. For example, an azo compound such as azodicarbonamide (ADCA), N, N′— Examples thereof include nitroso compounds such as dinitrosopentamethylenetetramine, hydrazine derivatives such as 4,4′-oxybis (benzenesulfonylhydrazide) (OBSH) and hydrazodicarbonamide (HDCA), and sodium bicarbonate.
The blending amount of the foaming agent is preferably 0.1 to 10 parts by weight, more preferably 0.1 to 5 parts by weight with respect to 100 parts by weight of the base resin.

  The coating layer 4 may contain various known additives such as fillers, lubricants, antioxidants, processing aids, neutralizers, ultraviolet absorbers, pigments, antistatic agents, and dispersants as necessary. It can also be blended.

  Examples of the filler include organic bromine-containing flame retardants such as brominated ethylene bisphthalimide derivatives, bisbrominated phenylterephthalamide derivatives, brominated bisphenol derivatives, and 1,2-bis (bromophenyl) ethane; magnesium hydroxide And inorganic flame retardants such as aluminum hydroxide; phosphoric acid flame retardants such as aromatic condensed phosphate ester, ammonium polyphosphate, and melamine phosphate; ammonium polyphosphate, melamine polyphosphate, piperazine polyphosphate, pyrophosphate Intensescent flame retardants such as ammonium, melamine pyrophosphate, and piperazine pyrophosphate; light calcium carbonate, heavy calcium carbonate, mica, pentonite, zeolite, slaked lime, kaolin, and diatomaceous earth.

  Examples of the lubricant include hydrocarbon lubricants, fatty acid lubricants, ester lubricants, and the like.

  Examples of the antioxidant include a phenolic antioxidant, an amine antioxidant, and a phosphorus antioxidant.

  Examples of the processing aid include petroleum oils such as paraffinic oils, aromatic oils, and naphthenic oils.

  Examples of the ultraviolet absorber include benzophenone compounds, benzotriazole compounds, salicylate compounds, substituted tolyl compounds, and metal chelate compounds.

  As the pigment, general inorganic pigments and organic pigments described in “Handbook of Pigments (edited by the Japan Pigment Technical Association)” can be used. For example, examples of the inorganic pigment include (composite) metal oxides containing titanium such as titanium yellow, zinc oxide, iron oxide, zinc sulfide, and antimony trioxide. Organic pigments include phthalocyanine, anthraquinone, quinacridone, azo, isoindolinone, quinophthalone, perinone, and perylene pigments.

  Examples of the antistatic agent include alkyl phosphate esters and silicate compounds.

  Examples of the dispersant include acrylic dispersants, fatty acid ester dispersants, polyethylene glycol dispersants, nonionic surfactants, amphiphilic triphenylene derivatives, and pyrene derivatives.

  The polyolefin-based foamable resin composition in the present invention preferably contains a filler and a lubricant. The amount of the filler is preferably 10 to 90 parts by weight with respect to 100 parts by weight of the base resin. -60 parts by weight is more preferred. The lubricant is preferably 0.5 to 10 parts by weight, more preferably 1 to 2 parts by weight. When the blending amount of the filler is 10 parts by weight or more, easiness of tearing and peelability are improved, and when it is 90 parts by weight or less, deterioration of the tensile strength is prevented. Further, when the blending amount of the lubricant is 0.5 parts by weight or more, the ease of tearing and the peelability are improved, and when it is 90 parts by weight or less, deterioration of the tensile strength is prevented.

As described above, the method for producing a foamed polyolefin-coated wire / cable of the present invention includes the following steps (1) to (4).
(1) Step of preparing a polyolefin-based foamable resin composition by mixing at least a base resin containing a polyolefin-based resin, a crosslinking agent, a crosslinking aid, and a foaming agent (2) Polyolefin prepared in the step (1) Step (3) for obtaining a cross-linked product of a polyolefin-based foamable resin composition by cross-linking a foamed resin composition and extruding the cross-linked product obtained in the step (2) and coating the outer periphery of the conductor with the cross-linked product. Step for forming layer (4) Step for foaming coating layer formed in step (3)

  In the step (1), as a method for producing the polyolefin-based foamable resin composition, the base resin, the cross-linking agent, the cross-linking aid, and the foaming agent, and other various additives added as necessary, are used. The method of mixing uniformly using a well-known mixing means is illustrated.

  In the step (2), the method for crosslinking the polyolefin-based foamable resin composition is not particularly limited, and any conventionally known method can be adopted.

From the viewpoint of the effect of the present invention, the degree of crosslinking of the polyolefin-based foamable resin composition is preferably 1 to 50%, and more preferably 3 to 40%.
The degree of cross-linking conforms to the test of item 27 of JISC3005. Specifically, a 5 g sample of a polyolefin-based foamable resin composition after crosslinking is prepared, the sample is immersed in 100 g of a solvent xylene, the temperature of the solvent is kept at 120 ° C. for 24 hours, and The sample is taken out from the solvent, placed in a vacuum desiccator, and dried at a temperature of 100 ± 2 ° C. and a vacuum degree of 1.3 kPa (10 Torr) or less for 24 hours or more. After drying, the weight of the sample (mass after the test) is measured to the unit of mg and expressed as a percentage compared to the initial weight of the sample (mass before the test).

  In the step (3), the method for extruding the crosslinked body is not particularly limited. For example, the crosslinked body obtained in the step (2) is extruded using a known single-screw extruder or twin-screw extruder. A coating layer 4 made of the crosslinked body can be formed on the outer periphery of the conductor 2. Moreover, in this extrusion process, a coating layer foams as said process (4), and the foaming polyolefin covering electric wire and cable of this invention are manufactured.

The foamed polyolefin-coated electric wire / cable of the present invention can be produced by the production method described above, and has a conductor 2 and a coating layer 4 that is foamed and contains a polyolefin-based resin on the outer periphery of the conductor 2. The foaming rate of the coating layer 4 is 3 to 30%, and the radial orientation of the cross-linked polyolefin resin in the coating layer 4 is larger than the axial orientation.
When the foaming rate of the coating layer 4 is 3% or more, the ease of tearing and peelability are improved, and when it is 30% or less, mechanical properties such as tensile strength and heat-resistant deformation are improved. The foaming ratio is more preferably 5 to 25%. In the present invention, before the coating layer 4 is formed on the outer periphery of the conductor 2, the polyolefin-based foamable resin composition is cross-linked to stabilize foaming and increase foaming (for example, a foaming ratio of 10% or more). However, if the polyolefin-based foamable resin composition is crosslinked after forming the coating layer 4 on the outer periphery of the conductor 2, foaming is not stable and the appearance is poor.

  In addition, the foaming rate as used in the field of this invention is computed from the specific gravity ratio before foaming and after foaming.

  In the present invention, since the polyolefin-based foamable resin composition is crosslinked before the coating layer 4 is formed on the outer periphery of the conductor 2, the radial orientation of the crosslinked product of the polyolefin-based resin in the coating layer 4. However, it becomes larger compared to the orientation in the axial direction, thereby improving the ease of tearing and peelability in the longitudinal direction of the electric wire / cable. The orientation of the crosslinked product can be confirmed by SEM or the like in the traveling direction of the dispersed rubber component.

  As shown in FIG. 2, when the coating layer 4 has a two-layer structure composed of a lower layer 41 and an upper layer 42, for example, the density of the polyolefin resin in the lower layer 41 and the upper layer 42 is made different, and desired properties (for example, heating Deformation characteristics, heat resistance, etc.) can be assigned to each layer.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further, this invention is not restrict | limited to the following example.

The following materials were used.
EVA: Mitsubishi Chemical Corporation A543
PP: Novatec BC8A manufactured by Nippon Polypropylene Co., Ltd.
EPDM: EP07AP manufactured by JSR Corporation
Organic peroxide: Perhexa 25B (2,5-dimethyl-2,5-di- (tert-butylperoxy) hexane) manufactured by NOF Corporation
Crosslinking aid: NK ester 3G (triethylene glycol dimethacrylate) manufactured by Shin-Nakamura Chemical Co., Ltd.
Filler: Magnesium hydroxide Lubricant: NOF Co., Ltd. calcium stearate Foaming agent: Eiwa Kasei ADCA (Azodicarbonamide) EV405D

[Test wires A1 to A99]
According to the blending amounts (parts by weight) shown in Tables 1 to 4, each component was kneaded with a kneader having a temperature of 200 ° C. to prepare a polyolefin-based foamable resin composition.
Subsequently, a crosslinking agent and a crosslinking aid were added, and the mixture was kneaded at 190 ° C. for 3 minutes or longer to prepare a crosslinked body.
Subsequently, using an extruder, each cross-linked body is coated with an insulator on a copper wire having a diameter of 2.0 mm so that the thickness is 0.8 mm, and further on top of that, the coating made of the cross-linked body is 1.5 mm. A layer was formed to produce a test wire (flat 3 × 2.0).

Each test wire was evaluated as follows.
Foaming rate: calculated by the specific gravity ratio before foaming and after foaming.
Tensile strength: Measured by carrying out the tensile test of Section 4.16 of JIS C3005. The standard value of 10 MPa or more was described as A, and the sample not satisfying the standard value was described as B.
Heat deformation (75 ° C.): Measured by carrying out heat deformation according to 4.23 of JIS C3005. Those satisfying the standard value were described as A, and those not satisfying the standard value as B.
Peelability: Cut the test cable, install a knife in the lower chuck part of the tensile tester, and install the test cable with a cut in the upper chuck part with the knife in place to perform a tensile test It was measured by. The peel load of less than 40N was described as A, and 40N or more was described as B.
Extrusion appearance: Checks for sight and the like by visual inspection and palpation. Absence or the like is indicated as A, and presence or the like is indicated as B.
A result is combined with Tables 1-4 and shown.

[Test wires B1 to B146]
Test wires were produced in the same manner as in the test wires A1 to A99 except that a polyolefin-based foamable resin composition was produced according to the blending amounts (parts by weight) shown in Tables 5 to 10. The results are shown in Tables 5-10.

  Furthermore, based on various parameters of tensile strength, heat deformation (75 ° C.), peelability, and extrusion appearance measured and calculated in test wires A1 to A99 and B1 to B146, comprehensive evaluation of various test wires was performed. . In this comprehensive evaluation, evaluation A indicates that all the evaluations of the various parameters are A, and evaluation B indicates that among the various parameters, evaluation of A is three and evaluation of B is one. , Evaluation C indicates that among the various parameters, A has two evaluations and B has two evaluations, and evaluation D has one of the various parameters, A has one evaluation, and B has three evaluations. The evaluation E indicates that all the evaluations are B among the various parameters.

Each test wire manufactured by carrying out the manufacturing method of the present invention achieves higher foaming compared to the test wire produced by the conventional method of crosslinking the polyolefin-based foamable resin composition after forming the coating layer The ease of tearing and peelability were improved. Also, mechanical properties such as high tensile strength and resistance to heat denaturation were obtained.
In particular, the test wires A1 to A99 produced by the method for producing a foamed polyolefin-coated wire / cable having the configuration of the present invention are the composition of the base resin in the polyolefin-based foamable resin composition, the content thereof, the content of the foaming agent, and the filling Since the material content and the lubricant content are specified, the overall evaluation is A, and the stabilization of foaming, ease of tearing and peelability, and mechanical properties could be further improved. .

  In addition, when the orientation direction of the cross-linked product of the coating layer in each test electric wire produced by carrying out the production method of the present invention was confirmed by the above method, the radial orientation of the cross-linked product was compared with the axial direction orientation. It turned out to be big.

  In addition, this invention is not limited to said each embodiment, A various modification can be employ | adopted within the scope of the present invention. For example, the present invention is not limited to the above-described embodiments, and modifications, improvements, and the like can be made as appropriate. In addition, the material, shape, dimensions, number, arrangement location, and the like of each component in the above-described embodiment are arbitrary and are not limited as long as the present invention can be achieved.

Here, the manufacturing method of the above-described foamed polyolefin-coated electric wire / cable according to the present invention and the features of the embodiment of the foamed polyolefin-coated electric wire / cable manufactured by the manufacturing method are briefly described as [1] to [4] below. List them together.
[1]
The manufacturing method of foaming polyolefin covering electric wire and a cable including the process of following (1)-(4).
(1) Step of preparing a polyolefin-based foamable resin composition by mixing at least a base resin containing a polyolefin-based resin, a crosslinking agent, a crosslinking aid, and a foaming agent (2) Polyolefin prepared in the step (1) Step (3) for obtaining a cross-linked product of a polyolefin-based foamable resin composition by cross-linking a foamed resin composition and extruding the cross-linked product obtained in the step (2) and coating the outer periphery of the conductor with the cross-linked product. Step (4) of forming a layer Step of foaming the coating layer formed in the step (3) [2]
The polyolefin-based foamable resin composition is
Containing 0.02 to 0.5 parts by weight of the crosslinking agent with respect to 100 parts by weight of the base resin;
The crosslinking aid contains 1-3 times the amount of the crosslinking agent.
The manufacturing method of the foamed polyolefin covering electric wire and cable as described in said (1).
[3]
In the polyolefin-based foamable resin composition,
The base resin contains 60 to 95 parts by weight of the polyolefin resin and 5 to 40 parts by weight of a rubber component,
The content of the foaming agent is 0.1 to 10 parts by weight,
The polyolefin-based foamable resin composition further contains 10 to 90 parts by weight of a filler,
Containing 0.5 to 10 parts by weight of the lubricant,
The manufacturing method of the foamed polyolefin covering electric wire and cable as described in said (2).
[4]
A foamed polyolefin-coated electric wire / cable (1, 10) having a conductor (2) and a coating layer (4) foamed and containing a polyolefin-based resin on the outer periphery of the conductor (2),
The foaming rate of the coating layer (4) is 3 to 30%,
The radial orientation of the cross-linked polyolefin resin in the coating layer (4) is larger than the axial orientation,
Foamed polyolefin-coated wires and cables (1,10).

DESCRIPTION OF SYMBOLS 1 Electric wire 2 Conductor 3 Insulator 4 Covering layer 10 Cable 41 Lower layer 42 Upper layer

Claims (4)

The manufacturing method of foaming polyolefin covering electric wire and a cable including the process of following (1)-(4).
(1) Step of preparing a polyolefin-based foamable resin composition by mixing at least a base resin containing a polyolefin-based resin, a crosslinking agent, a crosslinking aid, and a foaming agent (2) Polyolefin prepared in the step (1) Step (3) for obtaining a cross-linked product of a polyolefin-based foamable resin composition by cross-linking a foamed resin composition and extruding the cross-linked product obtained in the step (2) and coating the outer periphery of the conductor with the cross-linked product. Step for forming layer (4) Step for foaming coating layer formed in step (3) The polyolefin-based foamable resin composition is
Containing 0.02 to 0.5 parts by weight of the crosslinking agent with respect to 100 parts by weight of the base resin;
The crosslinking aid contains 1-3 times the amount of the crosslinking agent.
The manufacturing method of the foamed polyolefin covering electric wire and cable of Claim 1. In the polyolefin-based foamable resin composition,
The base resin contains 60 to 95 parts by weight of the polyolefin resin and 5 to 40 parts by weight of a rubber component,
The content of the foaming agent is 0.1 to 10 parts by weight,
The polyolefin-based foamable resin composition further contains 10 to 90 parts by weight of a filler,
Containing 0.5 to 10 parts by weight of a lubricant;
The manufacturing method of the foamed polyolefin covering electric wire and cable of Claim 2. A foamed polyolefin-coated electric wire / cable having a conductor and a coating layer that is foamed and contains a polyolefin-based resin on the outer periphery of the conductor,
The foaming rate of the coating layer is 3 to 30%,
The radial orientation of the polyolefin resin cross-linked product in the coating layer is larger than the axial orientation,
Foamed polyolefin-coated wires and cables.