JP2024048588A - Chlorine-containing crosslinkable resin composition, chlorine-containing crosslinkable resin composition, cabtyre cable, and method for producing silane-crosslinked chlorine-containing resin molded article - Google Patents

Abstract

[Problem] To provide a chlorine-containing crosslinkable resin composition and a chlorine-containing crosslinkable resin composition that have excellent flexibility and high strength while also having excellent high-temperature properties, a method for producing a silane-crosslinked chlorine-containing resin molded article, and a cab-tire cable. [Solution] A chlorine-containing crosslinkable resin composition containing a chlorine-containing resin containing chlorinated polyethylene and polyvinyl chloride, an ethylene-carbon monoxide copolymer, a plasticizer, an organic peroxide, and an inorganic filler in specific ratios, wherein the ethylene-carbon monoxide copolymer contains at least one of an ethylene-vinyl acetate-carbon monoxide copolymer and an ethylene-(meth)acrylic acid ester-carbon monoxide copolymer, and the chlorine-containing crosslinkable resin composition when crosslinked has a tensile strength of 10.0 MPa or more, and the value obtained by dividing the tensile strength by the 100% modulus is 1.20 to 5.00, the chlorine-containing crosslinkable resin composition, the method for producing a silane-crosslinked chlorine-containing resin molded article, and a cab-tire cable. [Selected drawing] Figure 1

Description

The present invention relates to a chlorine-containing crosslinkable resin composition, a chlorine-containing crosslinkable resin composition, a cab-tire cable, and a method for producing a silane-crosslinked chlorine-containing resin molded body.

Wiring materials such as insulated wires, cables, cords, optical fiber cores, and optical fiber cords (optical fiber cables) used in the fields of electrical and electronic equipment, industry, and automobiles are required to have various properties such as heat resistance and mechanical properties (e.g., tensile properties). For example, a cab-tyre cable, which is an insulated wire having a conductor and an insulating layer on its outer periphery and a sheath provided on the outer periphery, is mainly used as a power supply wire at a construction site, for example, an electric wire for electrically connecting moving parts of machine tools, and is bent and, after installation, is routed, for example, on a concrete floor surface. For this reason, the cab-tyre cable is required to have excellent flexibility (bending ability) and high strength.
As such a cabtyre cable, Patent Document 1 describes a cabtyre cable having an insulating layer made of a silanol condensation cured product of a specific silane crosslinkable composition for insulating layer, and a sheath made of a silanol condensation cured product of "a silane crosslinkable composition for sheath containing, relative to 100 parts by mass of base resin (B) containing a halogen-containing resin, 1 to 200 parts by mass of inorganic filler (Q), and more than 2 parts by mass and not more than 15.0 parts by mass of a silane coupling agent (F) which has been graft-reacted with the base resin (B), and further containing a silanol condensation catalyst (Y)."

JP 2019-179689 A

However, since wiring materials are used while energized, they can self-heat and reach high temperatures (for example, 60°C or higher). Cabtyre cables in particular generate a large amount of heat when energized, and because they are routed while energized, they are bent even at high temperatures, making it important for them to have high-temperature properties that maintain high strength as a resistance to the stress (physical load) that occurs when they are routed. However, Patent Document 1 does not consider this point of view.

The present invention aims to provide a chlorine-containing crosslinkable resin composition that has excellent flexibility and high strength while also having excellent high-temperature properties, and a chlorine-containing crosslinkable resin composition that can be used to produce this chlorine-containing crosslinkable resin composition. Another object of the present invention is to provide a cab-tire cable that uses the chlorine-containing crosslinkable resin composition. A further object of the present invention is to provide a method for producing a silane-crosslinked chlorine-containing resin molded product.

The present inventors have intensively studied crosslinkable resin compositions for forming the insulating layer or sheath of wiring materials, and have found that a chlorine-containing crosslinkable resin composition having excellent flexibility and high strength and maintaining high strength even at high temperatures can be produced by combining a specific ethylene-carbon monoxide copolymer, a plasticizer, and an inorganic filler in a specific ratio with a chlorine-containing resin containing chlorinated polyethylene and polyvinyl chloride, and then setting the tensile strength when crosslinked to 10 MPa or more and the value obtained by dividing the tensile strength by the 100% modulus to 1.20 to 5.00. The present inventors have also found that a silane-crosslinked chlorine-containing resin molded article can be produced as a molded article of the chlorine-containing crosslinkable resin composition having the above-mentioned excellent properties with ease and high productivity without requiring special equipment by applying a silane crosslinking method to the preparation of the chlorine-containing crosslinkable resin composition, and further found that the chlorine-containing crosslinkable resin composition having the above-mentioned excellent properties is suitable as a sheath material for a cabtyre cable.
Based on this finding, the present inventors have further investigated and have arrived at the present invention.

That is, the object of the present invention has been achieved by the following means.
<1> A chlorine-containing crosslinkable resin composition comprising, relative to 100 parts by mass of a chlorine-containing resin, 5 to 60 parts by mass of an ethylene-carbon monoxide copolymer, 5 to 40 parts by mass of a plasticizer, 0.01 to 5.0 parts by mass of an organic peroxide, and 0.5 to 100 parts by mass of an inorganic filler,
the chlorine-containing resin comprises chlorinated polyethylene and polyvinyl chloride;
the ethylene-carbon monoxide copolymer comprises at least one of an ethylene-vinyl acetate-carbon monoxide copolymer and an ethylene-(meth)acrylic acid ester-carbon monoxide copolymer;
The chlorine-containing crosslinkable resin composition has a tensile strength of 10.0 MPa or more when crosslinked, and the value obtained by dividing the tensile strength by the 100% modulus is 1.20 to 5.00.
<2> The chlorine-containing crosslinkable resin composition according to <1>, wherein the content of the organic peroxide is 0.01 to 0.5 parts by mass, and the composition further comprises, per 100 parts by mass of the chlorine-containing resin, 1 to 15 parts by mass of a silane coupling agent having a grafting reaction site capable of undergoing a grafting reaction in the presence of radicals generated from the organic peroxide, and a silanol condensation catalyst.
<3> The chlorine-containing crosslinkable resin composition according to <1> or <2>, wherein the ethylene-carbon monoxide copolymer is an ethylene-(meth)acrylic acid ester-carbon monoxide copolymer.
<4> The chlorine-containing crosslinkable resin composition according to any one of <1> to <3>, wherein, in the chlorine-containing resin, the content of the chlorinated polyethylene is 50 to 90 mass% and the content of the polyvinyl chloride is 10 to 50 mass% in a total of 100 mass% of the chlorinated polyethylene and the polyvinyl chloride.
<5> The chlorine-containing crosslinkable resin composition according to any one of <1> to <4>, wherein the chlorinated polyethylene includes a non-crystalline chlorinated polyethylene.
<6> The chlorine-containing crosslinkable resin composition according to <5>, wherein the content of the amorphous chlorinated polyethylene in the chlorinated polyethylene is 80 mass%.
<7> The chlorine-containing crosslinkable resin composition according to any one of <1> to <6>, wherein the chlorinated polyethylene contains chlorine of 30% or more and less than 38%.
<8> The chlorine-containing crosslinkable resin composition according to any one of <1> to <7>, wherein the chlorinated polyethylene includes a chlorinated polyethylene having a chlorine content of 30% or more and less than 38% and a chlorinated polyethylene having a chlorine content of 38% or more and less than 42%.
<9> The chlorine-containing crosslinkable resin composition according to any one of <1> to <8>, wherein the chlorine-containing resin comprises 30 to 50 mass% of a chlorinated polyethylene having a chlorine content of 30% or more and less than 38%, 10 to 30 mass% of a chlorinated polyethylene having a chlorine content of 38% or more and less than 42%, and 10 to 50 mass% of polyvinyl chloride.
<10> A chlorine-containing crosslinkable resin composition obtained by subjecting the chlorine-containing crosslinkable resin composition according to any one of <1> to <9> above to a crosslinking reaction treatment,
A chlorine-containing crosslinked resin composition having a tensile strength of 10.0 MPa or more, and a value obtained by dividing the tensile strength by a 100% modulus of 1.20 to 5.00.
<11> A cabtyre cable having a sheath made of the chlorine-containing crosslinked resin composition according to <10> above.

<12> A method for producing a silane-crosslinked chlorine-containing resin molded product having a tensile strength of 10.0 MPa or more and a value obtained by dividing the tensile strength by a 100% modulus of 1.20 to 5.00, comprising the steps (1), (2), and (3) below:
Step (1): 5 to 6 parts by mass of ethylene-carbon monoxide copolymer per 100 parts by mass of chlorine-containing resin
0 parts by weight, 5 to 40 parts by weight of a plasticizer, and 0.01 to 0.5 parts by weight of an organic peroxide.
parts by mass, 0.5 to 100 parts by mass of an inorganic filler, and
The grafting reaction site is capable of undergoing a grafting reaction in the presence of a radical.
1 to 15 parts by mass of a run coupling agent and a silanol condensation catalyst are melt-mixed.
The graft reaction portion is then reacted with the radicals generated from the organic peroxide.
and a grafting reaction between the grafting site of the chlorine-containing resin and the grafting site of the chlorine-containing resin.
Step (2): The chlorine-containing silane-crosslinkable resin composition is molded to obtain a molded body. Step (3): The molded body is contacted with water to obtain a silane-crosslinked chlorine-containing resin molded body.

the chlorine-containing resin comprises chlorinated polyethylene and polyvinyl chloride;
the ethylene-carbon monoxide copolymer comprises at least one of an ethylene-vinyl acetate-carbon monoxide copolymer and an ethylene-(meth)acrylic acid ester-carbon monoxide copolymer;
In the step (1), when the whole of the chlorine-containing resin is melt-mixed in the following step (a-2), the step (1) comprises the following steps (a-1), (a-2), and (c); and in the step (a-2), when a part of the chlorine-containing resin is melt-mixed, the step (1) comprises the following steps (a-1), (a-2), (b), and (c).

Step (a-1): The inorganic filler and the silane coupling agent are mixed to prepare a mixture.
Step (a-2): mixing the mixture, all or a part of the chlorine-containing resin, and ethylene-carbon monoxide.
The copolymer and the plasticizer are mixed in the presence of the organic peroxide.
The grafting reaction site is melt-mixed at a temperature equal to or higher than the decomposition temperature of
and the graftable portion,
Step (b): preparing a silane master batch by melt-mixing the remainder of the chlorine-containing resin and the silanol condensation catalyst to form a catalyst master batch.
Step (c) of preparing a master batch: The silane master batch and the silanol condensation catalyst or the catalyst master batch are mixed.
The chlorine-containing silane crosslinkable resin composition is prepared by melt-mixing the above batch.
Process

<13> The manufacturing method according to <12>, wherein, in the chlorine-containing resin, the content of the chlorinated polyethylene is 50 to 90 mass%, and the content of the polyvinyl chloride is 10 to 50 mass%, based on a total of 100 mass% of the chlorinated polyethylene and the polyvinyl chloride.
＜14＞
The method according to <12> or <13>, wherein the chlorinated polyethylene contains 80 mass% or more of amorphous chlorinated polyethylene.
<15> The method according to any one of <12> to <14>, wherein the chlorine-containing resin comprises 30 to 50 mass% of chlorinated polyethylene having a chlorine content of 30% or more and less than 38%, 10 to 30 mass% of chlorinated polyethylene having a chlorine content of 38% or more and less than 42%, and 10 to 50 mass% of polyvinyl chloride.
<16> A cabtyre cable having a sheath made of a silane-crosslinked chlorine-containing resin molded product produced by the production method according to any one of <12> to <15> above.

In this specification, a numerical range expressed using "~" means a range that includes the numerical values written before and after "~" as the upper and lower limits. In the present invention, when multiple numerical ranges are set for the content of a component, physical properties, etc., the upper and lower limits forming the numerical range are not limited to the combination of the specific upper and lower limits written before and after "~" as a specific numerical range, but can be a numerical range that appropriately combines the upper and lower limits of each numerical range.

The present invention can provide a chlorine-containing crosslinkable resin composition that has excellent flexibility and high strength while also having excellent high-temperature properties, and a chlorine-containing crosslinkable resin composition that can be used to produce this chlorine-containing crosslinkable resin composition. The present invention can also provide a cab-tire cable that uses the chlorine-containing crosslinkable resin composition. Furthermore, the present invention can provide a method for producing a silane-crosslinked chlorine-containing resin molded product.

FIG. 1 is an end view showing a structure of one embodiment of a cab-tire cable of the present invention. FIG. 2 is an end view showing the structure of another embodiment of the cab-tire cable of the present invention.

[Chlorine-containing crosslinkable resin composition]
The chlorine-containing crosslinkable resin composition of the present invention contains 5 to 60 parts by mass of an ethylene-carbon monoxide copolymer, 5 to 40 parts by mass of a plasticizer, 0.01 to 5.0 parts by mass of an organic peroxide, and 0.5 to 100 parts by mass of an inorganic filler, relative to 100 parts by mass of a chlorine-containing resin containing a chlorinated polyethylene and a polyvinyl chloride. The chlorine-containing crosslinkable resin composition having this composition has a tensile strength of 10.0 MPa or more when crosslinked, and a value obtained by dividing the tensile strength by the 100% modulus is 1.20 to 5.00 (a chlorine-containing crosslinkable resin composition having a tensile strength of 10.0 MPa or more and a value obtained by dividing the tensile strength by the 100% modulus of 1.20 to 5.00 can be produced).

The crosslinking reaction (crosslinking method) for crosslinking the chlorine-containing crosslinkable resin composition is not particularly limited, and any known resin crosslinking method can be applied. For example, organic peroxide crosslinking method and silane crosslinking method can be used. Silane crosslinking method is preferred because it does not require special equipment and can perform crosslinking reaction treatment easily and with high productivity.
In the present invention, the organic peroxide crosslinking method is one of the chemical crosslinking methods, and refers to a method (organic peroxide crosslinking method) in which chlorine-containing resins are directly crosslinked with each other by radicals generated by decomposing organic peroxides by applying heat. The silane crosslinking method is a chemical crosslinking method different from the organic peroxide crosslinking method, and refers to a method in which a chlorine-containing crosslinkable composition containing an organic peroxide as a crosslinking catalyst is heated to a temperature equal to or higher than the decomposition temperature of the organic peroxide to graft a silane coupling agent as a crosslinking agent to a chlorine-containing resin by radicals generated from the organic peroxide to obtain a silane graft resin, which is then molded as desired, and then the silane graft resin is brought into contact with moisture, preferably in the presence of a silanol condensation catalyst, to cause a silane coupling agent to undergo a silanol condensation reaction. Incidentally, an ethylene-carbon monoxide copolymer may also undergo a crosslinking reaction in the organic peroxide crosslinking method, and may also undergo a graft reaction in the silane crosslinking method.

The chlorine-containing crosslinkable resin composition of the present invention may be any composition that can crosslink at least the chlorine-containing resin by the crosslinking reaction treatment described below, and preferably further contains essential or suitable components according to the crosslinking method to be applied, such as a crosslinking agent, a crosslinking assistant, a crosslinking catalyst, and a crosslinking accelerator. Specifically, when the chlorine-containing crosslinkable resin composition of the present invention is subjected to a crosslinking reaction by the silane crosslinking method, it further contains a silane coupling agent and a silanol condensation catalyst in addition to the above components.

In the present invention, the chlorine-containing crosslinkable resin composition that can be suitably applied to the organic peroxide crosslinking method or the silane crosslinking method may be referred to as a chlorine-containing crosslinkable resin composition for organic peroxide crosslinking and a chlorine-containing crosslinkable resin composition for silane crosslinking, respectively.

(Chlorine-containing crosslinkable resin composition for silane crosslinking)
The chlorine-containing crosslinkable resin composition for silane crosslinking is a composition containing the above-mentioned components, and is preferably a crosslinkable composition containing 5 to 60 parts by mass of an ethylene-carbon monoxide copolymer, 5 to 40 parts by mass of a plasticizer, 0.5 to 100 parts by mass of an inorganic filler, 1 to 15 parts by mass of a silane coupling agent, and a silanol condensation catalyst, relative to 100 parts by mass of the chlorine-containing resin, in which the silane coupling agent is grafted to the chlorine-containing resin or the ethylene-carbon monoxide copolymer by radicals generated by the decomposition reaction of an organic peroxide. This chlorine-containing silane crosslinkable resin composition can be prepared by an appropriate method, but is preferably prepared by step (1) in the method for producing a silane-crosslinked chlorine-containing resin molded body of the present invention described later. In this chlorine-containing silane crosslinkable resin composition, the silane coupling agent may be bonded or dissociated with the inorganic filler.
The chlorine-containing crosslinkable resin composition for silane crosslinking, in particular the chlorine-containing silane crosslinkable resin composition, is suitably used for the production of a chlorine-containing crosslinkable resin composition which has both excellent flexibility and high strength and also excellent high-temperature properties, in particular for the production method of the chlorine-containing crosslinked resin molding of the present invention.

[Chlorine-containing crosslinked resin composition]
The chlorine-containing crosslinkable resin composition of the present invention is a chlorine-containing crosslinkable resin composition obtained by subjecting the chlorine-containing crosslinkable resin composition of the present invention to a crosslinking reaction treatment, and is also referred to as a crosslinked cured product of the chlorine-containing crosslinkable resin composition of the present invention.
This chlorine-containing crosslinked resin composition has a crosslinked structure in which a chlorine-containing resin, a normal chlorinated polyethylene, and an ethylene-carbon monoxide copolymer are crosslinked, and as described below, an inorganic filler may be incorporated into the crosslinked structure. The crosslinked structure is determined according to the crosslinking reaction applied to the chlorine-containing crosslinkable resin composition. For example, when the organic peroxide crosslinking method is applied, the composition usually has a structure in which resins are directly crosslinked with each other. On the other hand, when the silane crosslinking method is applied, the composition preferably has a crosslinked structure via a silane coupling agent or a silanol condensate thereof, and an inorganic filler is incorporated into a part of the crosslinked structure.
In the present invention, a chlorine-containing crosslinked resin composition (silanol condensation cured product) obtained by crosslinking a silane-crosslinkable chlorine-containing resin composition by a silane crosslinking method (grafting reaction of a silane coupling agent and silanol condensation reaction) is referred to as a silane-crosslinked chlorine-containing resin composition.
The chlorine-containing crosslinking resin composition of the present invention includes a molded article molded into a predetermined shape and size, and the molded chlorine-containing crosslinking resin composition is referred to as a chlorine-containing crosslinked resin molded article, and the molded silane-crosslinked chlorine-containing resin composition is referred to as a silane-crosslinked chlorine-containing resin molded article.

The chlorine-containing crosslinked resin composition of the present invention has excellent flexibility and high strength, while also having excellent high-temperature properties. The reason for this is unclear, but is thought to be as follows. By containing a specific ethylene-carbon monoxide copolymer, a plasticizer, and an inorganic filler in specific ratios in a chlorine-containing resin containing chlorinated polyethylene and polyvinyl chloride, it is thought that the various components work together to suppress a decrease in flexibility even when the strength is increased by a crosslinking reaction treatment. Furthermore, since the strength and the value obtained by dividing the tensile strength by the 100% modulus of the chlorine-containing crosslinked resin composition are set within a specific range, it is thought that a significant decrease in strength can be suppressed even at high temperatures while maintaining excellent flexibility.

The chlorine-containing crosslinked resin composition of the present invention has a tensile strength of 10.0 MPa or more when measured on a tubular test piece described in the examples under the conditions of a gauge length of 20 mm and a tensile speed of 200 mm/min based on Japanese Industrial Standards (JIS) C 3005. If the tensile strength is 10.0 MPa or more, the chlorine-containing crosslinked resin composition exhibits excellent strength. The tensile strength of the chlorine-containing crosslinked resin composition is preferably 12.0 MPa or more, more preferably 13.0 MPa or more. The upper limit of the tensile strength is not particularly limited, and can be practically set to 25.0 MPa or less, but is preferably set to 15.0 MPa or less in consideration of the balance with flexibility.
In the present invention, the tensile strength of the chlorine-containing crosslinkable resin composition can be adjusted by the composition of the chlorine-containing crosslinkable resin composition (type and content of each component) and the selection of the crosslinking method. For example, the tensile strength tends to decrease when the content of the plasticizer is increased. In addition, the content of polyvinyl chloride and the content of inorganic filler also tend to affect the tensile strength.

The chlorine-containing crosslinkable resin composition of the present invention has a tensile strength divided by 100% modulus (hereinafter sometimes referred to as "strength modulus ratio") of 1.20 to 5.00 when measured on a tubular test piece described in the examples based on JIS C 3005 under the conditions of a gauge length of 20 mm and a tensile speed of 200 mm/min. When the strength modulus ratio is within this range, the composition is excellent in high temperature properties while achieving both excellent flexibility and high strength. That is, when the strength modulus ratio is 1.20 or less, even if the composition of the chlorine-containing crosslinkable resin composition (type and content of each component) is within the range described below, the strength becomes too high and the hardness becomes high. On the other hand, when the strength modulus ratio exceeds 5.00, even if the composition of the chlorine-containing crosslinkable resin composition is within the range described below, the composition becomes too soft. In either case, it becomes impossible to achieve both excellent flexibility and high strength, and the composition is also inferior in high temperature properties. The strength modulus ratio of the chlorine-containing crosslinked resin composition is preferably 1.50 to 4.00, more preferably 1.50 to 3.30, and even more preferably 1.80 to 3.30, in order to exhibit excellent high-temperature properties while achieving a good balance between excellent flexibility and high strength.
In the present invention, the strength modulus ratio of the chlorine-containing crosslinkable resin composition can be adjusted by adjusting the strength and 100% modulus of the chlorine-containing crosslinkable resin composition.

The 100% modulus in the chlorine-containing crosslinked resin composition of the present invention is not particularly limited as long as it satisfies the above-mentioned strength modulus ratio, and can be appropriately set.For example, the 100% modulus is preferably 11.0 MPa or less, more preferably 9.0 MPa or less, and even more preferably 7.0 MPa or less, in order to be able to exhibit excellent flexibility in the chlorine-containing crosslinked resin composition.The lower limit of the 100% modulus is not particularly limited, and can be practically 2.0 MPa or more, and considering the balance with strength, it is preferably 3.0 MPa or more.
In the present invention, the 100% modulus of the chlorine-containing crosslinkable resin composition can be adjusted by selecting the composition of the chlorine-containing crosslinkable resin composition (type and content of each component) and the crosslinking method. For example, the 100% modulus tends to decrease when the content of the plasticizer is increased. In addition, the content of polyvinyl chloride and the content of inorganic filler also tend to affect the 100% modulus.

The chlorine-containing crosslinked resin composition of the present invention has excellent high-temperature properties while exhibiting high strength and excellent flexibility, and is particularly suitable for use as a sheath material for cab-tyre cables. The high-temperature properties exhibited by the chlorine-containing crosslinked resin composition of the present invention are properties that enable it to maintain high strength (suppress a significant decrease in strength) even when exposed to high temperatures (e.g., 60°C or higher) due to self-heating of the wiring material, and refer to a "maximum load force" of 18N or more in the "high-temperature crushing test" in the examples described below.

The silane-crosslinked chlorine-containing resin molded body produced by the chlorine-containing crosslinked resin composition of the present invention and the molded body production method of the present invention described below has excellent flexibility and high strength, and also has excellent high-temperature properties, and can be suitably used in various products (including semi-finished products, parts, and components). Specific examples include insulating layers or sheaths for wiring materials, molding materials, power plugs, connectors, sleeves, boxes, tape base materials, tubes, sheets, packings, gaskets, cushioning materials, and vibration-proofing materials. In particular, it is suitable for use as insulating layers for insulated electric wires for vehicles such as automobiles and trains, and sheaths for cab-tire cables.

Hereinafter, each component constituting the chlorine-containing crosslinkable resin composition and the chlorine-containing crosslinkable resin composition of the present invention (hereinafter, both may be collectively referred to as the resin composition of the present invention), and each component used in the method for producing a molded article of the present invention will be described.
Each of the components may be used alone or in combination of two or more.

<Chlorine-containing resin>
In the present invention, a chlorine-containing resin is used as the base resin constituting the resin composition of the present invention.
In the present invention, polyvinyl chloride and chlorinated polyethylene are used in combination as the chlorine-containing resin. By using polyvinyl chloride and chlorinated polyethylene as the base resin, flexibility, strength, and high-temperature properties can be improved. The chlorine-containing resin may contain a chlorine-containing resin other than polyvinyl chloride and chlorinated polyethylene (sometimes called other chlorine-containing resin), such as polyvinylidene chloride or chloroprene rubber.

(chlorinated polyethylene)
The chlorinated polyethylene is not particularly limited as long as it is a polyethylene in which hydrogen atoms bonded to the polyethylene main chain are replaced with chlorine atoms, and examples thereof include those obtained by chlorinating an ethylene (co)polymer. The chlorinated polyethylene usually has a site that undergoes a crosslinking reaction by an organic peroxide, or a site that can undergo a grafting reaction with a grafting reaction site of a silane coupling agent (e.g., an unsaturated bond site of a carbon chain or a carbon atom having a hydrogen atom) in the main chain or at its terminal. The mass average molecular weight of the chlorinated polyethylene is not particularly limited and can be appropriately set depending on the characteristics, applications, etc.

The crystallinity of the chlorinated polyethylene may be amorphous, semi-crystalline, or crystalline. However, amorphous chlorinated polyethylene is preferred because it is flexible yet exhibits high strength through crosslinking treatment, allowing the production of a chlorine-containing crosslinked resin composition that has both flexibility and strength and improved high-temperature properties. In the present invention, the crystallinity of the chlorinated polyethylene is determined by the heat of fusion (J/g) measured using a differential scanning calorimeter described in the examples.

The chlorinated polyethylene preferably has a chlorine content of 20% by mass or more, more preferably 25% by mass or more, and even more preferably 30% by mass or more. When the chlorine content is high, the polyethylene exhibits excellent flexibility while maintaining strength. The upper limit of the chlorine content is the mass ratio when all hydrogen atoms that can be replaced by chlorine atoms in the polyethylene before chlorination are replaced by chlorine atoms, and cannot be determined uniquely depending on the molecular weight of the polyethylene before chlorination, the number of hydrogen atoms that can be replaced by chlorine atoms, etc. For example, it is about 75% by mass. The chlorine content refers to the mass ratio of chlorine atoms to the total amount of chlorinated polyethylene, and can be quantified by potentiometric titration method described in JIS K 7229.
The chlorinated polyethylene used in the present invention preferably contains chlorinated polyethylene having a chlorine content of 30% or more and less than 38%, from the viewpoints of the balance between strength and flexibility and further the ease with which the crosslinking reaction proceeds, and more preferably contains chlorinated polyethylene having a chlorine content of 30% or more and less than 38% and chlorinated polyethylene having a chlorine content of 38% or more and less than 42%, from the viewpoints of achieving a high level of balance between flexibility and strength.

(PVC)
The polyvinyl chloride is not particularly limited as long as it is a polymer (homopolymer or copolymer) of polyvinyl chloride. Polyvinyl chloride is generally not easily crosslinked by organic peroxides, and is also not easily grafted by silane coupling agents. Examples of copolymers of vinyl chloride include copolymers of vinyl chloride and other vinyl monomers (compounds having ethylenic unsaturated bonds). Examples of other vinyl monomers are not particularly limited, and include, for example, ethylene, propylene, vinyl acetate, vinylidene chloride, (meth)acrylic acid, (meth)acrylic acid ester maleic acid, acrylonitrile, fumaric acid, acrylonitrile, alkyl vinyl ether, etc.
The average degree of polymerization of polyvinyl chloride is preferably 400 to 3,000, more preferably 700 to 2,600, and further preferably 700 to 1,500.

(Content of each resin)
The content of each resin (component) of the chlorine-containing resin is appropriately set within the following ranges so that the total content of chlorinated polyethylene, polyvinyl chloride and other chlorine-containing resins is 100 mass %.
The content (total content) of chlorinated polyethylene in the chlorine-containing resin is not particularly limited, but is preferably 50 to 90 mass%, more preferably 60 to 90 mass%, and even more preferably 60 to 80 mass%, in terms of increasing the crosslink density and being excellent in high-temperature properties while simultaneously achieving both flexibility and strength. On the other hand, the content of polyvinyl chloride in the chlorine-containing resin is not particularly limited, but is preferably 10 to 50 mass%, more preferably 10 to 40 mass%, and even more preferably 20 to 40 mass%, in terms of increasing the crosslink density and being excellent in high-temperature properties while simultaneously achieving both flexibility and strength. The content of the above other chlorine-containing resins in the chlorine-containing resin is appropriately determined within a range that does not impair the effects of the present invention, and can be, for example, 15 mass% or less.

The content of the non-crystalline chlorinated polyethylene in the chlorinated polyethylene can be appropriately set in consideration of the total content of the chlorinated polyethylene. For example, in order to achieve a good balance between flexibility and strength, it is preferably 80% by mass or more, more preferably 85% by mass or more, and more preferably 90% by mass or more. When semi-crystalline or crystalline chlorinated polyethylene is contained, the content of each in the chlorinated polyethylene is not particularly limited, but is preferably 20% by mass or less, more preferably 15% by mass or less, in order to achieve excellent flexibility and suppress the decrease in strength.
The content of the chlorinated polyethylene having a chlorine content of 30% or more and less than 38% and the content of the chlorinated polyethylene having a chlorine content of 38% or more and less than 42% can be appropriately set in consideration of the total content of the chlorinated polyethylene. For example, the content of the chlorinated polyethylene having a chlorine content of 30% or more and less than 38% is preferably 30 to 70 mass%, more preferably 30 to 50 mass%, and even more preferably 35 to 45 mass%, based on 100 mass% of the chlorine-containing resin, in order to achieve a high level of flexibility and strength in a well-balanced manner and to further excel in high-temperature properties. On the other hand, the content of the chlorinated polyethylene having a chlorine content of 38% or more and less than 42% is preferably 10 to 40 mass%, more preferably 10 to 30 mass%, and even more preferably 20 to 30 mass%, based on 100 mass% of the chlorine-containing resin, in order to achieve a high level of flexibility and strength in a well-balanced manner and to further excel in high-temperature properties.

<Ethylene-carbon monoxide copolymer>
In the present invention, an ethylene-carbon monoxide copolymer is used in combination with the chlorine-containing resin as the base resin constituting the resin composition of the present invention. The ethylene-carbon monoxide copolymer has a site that undergoes a crosslinking reaction with an organic peroxide, or a site that can undergo a grafting reaction with a grafting reaction site of a silane coupling agent, in the main chain or at its terminal. This ethylene-carbon monoxide copolymer is a copolymer of ethylene and carbon monoxide, but a terpolymer with an acid copolymerization component is used in terms of excellent compatibility with the chlorine-containing resin, compatibility with flexibility and strength, and particularly improved high-temperature properties. As the terpolymer, at least one of ethylene-vinyl acetate-carbon monoxide copolymer and ethylene-(meth)acrylic acid ester-carbon monoxide copolymer can be mentioned, and the ethylene-(meth)acrylic acid ester-carbon monoxide copolymer is preferred in terms of compatibility with flexibility and strength, particularly improved high-temperature properties.
The ethylene-carbon monoxide copolymer may contain at least one of an ethylene-vinyl acetate-carbon monoxide copolymer and an ethylene-(meth)acrylic acid ester-carbon monoxide copolymer, and may contain one or two types, and preferably contains one type.

(Ethylene-vinyl acetate-carbon monoxide copolymer)
The ethylene-vinyl acetate-carbon monoxide copolymer may be a copolymer of ethylene, vinyl acetate, and carbon monoxide, and various known copolymers can be used without any particular limitation. In the ethylene-vinyl acetate-carbon monoxide copolymer, the content of each component is not particularly limited and can be appropriately set. For example, the ethylene content is preferably 40 to 80 mass%, the vinyl acetate content is 5 to 50 mass%, and the carbon monoxide content is 3 to 30 mass%, and it is also possible to further copolymerize other monomers as necessary. Examples of the ethylene-vinyl acetate-carbon monoxide copolymer include Elbaloy (trade name, manufactured by DuPont).

(Ethylene-(meth)acrylic acid ester-carbon monoxide copolymer)
The ethylene-(meth)acrylic acid ester-carbon monoxide copolymer may be a copolymer of ethylene, a (meth)acrylic acid ester, and carbon monoxide, and various known copolymers can be used without any particular limitation. The (meth)acrylic acid ester may be an alkyl ester or an aryl ester, but an alkyl ester is preferred. The alkyl group forming the alkyl ester is preferably a straight chain or a branched chain, and the number of carbon atoms is preferably 1 to 18, and more preferably 1 to 6. Examples of the alkyl group include a methyl group, an ethyl group, a propyl group (n-propyl group, isopropyl group), a butyl group (n-butyl group, sec-butyl group, t-butyl group, isobutyl group), a hexyl group, an octyl group, a decyl group, and a dodecyl group. Specific examples of the ethylene-(meth)acrylic acid ester-carbon monoxide copolymer include an ethylene-butyl (meth)acrylate-carbon monoxide copolymer, an ethylene-ethyl acrylate-carbon monoxide copolymer, and an ethylene-methyl acrylate-carbon monoxide copolymer, and an example of a commercially available product is Elbaloy (trade name, manufactured by DuPont).
In the ethylene-(meth)acrylic acid ester-carbon monoxide copolymer, the content of each component is not particularly limited and can be appropriately set. For example, the content of ethylene is preferably 40 to 80 mass%, the content of (meth)acrylic acid ester is preferably 15 to 60 mass%, and the content of carbon monoxide is preferably 5 to 30 mass%, and other monomers can be further copolymerized as necessary.

<Plasticizer>
The plasticizer is not particularly limited, and various plasticizers that are usually used in chlorine-containing resins can be used without any particular limitation. By incorporating a plasticizer into the chlorine-containing crosslinkable resin composition of the present invention, it is possible to increase flexibility while suppressing the decrease in strength and high-temperature properties. Examples of the plasticizer include low-molecular-weight plasticizers such as phthalate ester plasticizers, trimellitate ester plasticizers (preferably, trialkyl trimellitate (alkyl group has 8 to 10 carbon atoms)), polyester plasticizers, adipate ester plasticizers, and pyromellitate ester plasticizers, and polymeric plasticizers such as polyester plasticizers, vinyl acetate copolymers, and (meth)acrylic acid ester copolymers. Among them, low-molecular-weight plasticizers are preferred, and from the viewpoint of plasticizing effect, phthalate ester plasticizers, trimellitate ester plasticizers, polyester plasticizers, adipate ester plasticizers, pyromellitate ester plasticizers, and the like are more preferred, and phthalate ester plasticizers are even more preferred. The hydrocarbon group constituting each ester is not particularly limited and may be an alkyl group, an aryl group, or the like, with an alkyl group being preferred. The number of carbon atoms in this hydrocarbon group is not particularly limited and is preferably, for example, 1 to 12, and more preferably 8 to 11. When each ester has multiple hydrocarbon groups in one molecule, they may be different from each other, but are preferably the same.

<Organic Peroxide>
The organic peroxide generates radicals at least by thermal decomposition, and acts as a catalyst to cause a crosslinking reaction between base resins in the organic peroxide crosslinking method, and a grafting reaction of a silane coupling agent to a base resin by a radical reaction in the silane crosslinking method (a covalent bond forming reaction between a grafting reaction site of the silane coupling agent and a site of the base resin capable of grafting reaction, also called a (radical) addition reaction). In particular, when the silane coupling agent contains an ethylenically unsaturated group as a grafting reaction site, it acts to cause a grafting reaction by a radical reaction between the ethylenically unsaturated group and a chlorine-containing resin, etc. (including a reaction of abstracting hydrogen radicals from the chlorine-containing resin, etc.).
The organic peroxide is not particularly limited as long as it generates radicals, and for example, compounds represented by the general formulas R ¹ -OO-R ² , R ³ -OO-C(═O)R ⁴ , and R ⁵ C(═O)-OO(C═O)R ⁶ are preferred. Here, R ¹ to R ⁶ each independently represent an alkyl group, an aryl group, or an acyl group. It is preferred that all of R ¹ to R ⁶ in each compound are alkyl groups, or that one is an alkyl group and the remaining is an acyl group.

Examples of such organic peroxides include those described in paragraph [0037] of WO 2015/046478, the contents of which are incorporated herein by reference as part of the present specification. In terms of odor, coloring, and scorch stability, dicumyl peroxide, 2,5-dimethyl-2,5-di-(tert-butylperoxy)hexane, and 2,5-dimethyl-2,5-di-(tert-butylperoxy)hexyne-3 are preferred.

The decomposition temperature of the organic peroxide is preferably 120 to 195° C., particularly preferably 125 to 180° C. The decomposition temperature of the organic peroxide is preferably equal to or lower than the reaction conditions of the crosslinking reaction, for example, in the silane crosslinking method, it is preferably equal to or lower than the melt mixing temperature in step (a-2) described later.
In the present invention, the decomposition temperature of an organic peroxide means a temperature at which an organic peroxide of a single composition undergoes a decomposition reaction into two or more compounds at a certain temperature or temperature range when heated under a normal pressure (about 0.1 MPa) environment. Specifically, it means a temperature at which heat absorption or heat generation begins when heated from room temperature at a temperature increase rate of 5°C/min under a nitrogen gas atmosphere (normal pressure) by thermal analysis such as DSC method.

<Inorganic filler>
In the present invention, the inorganic filler can be used without any particular restriction as the inorganic filler that is usually used in the manufacture of wiring materials. The inorganic filler preferably has a site on its surface that can adhere to the chlorine-containing resin by adsorption, bonding or interaction (for example, by interaction by hydrogen bond, interaction between ions, partial charges or dipoles, etc.), and in particular, when used in the silane crosslinking method described below, it can be used without any particular restriction as long as it has a site that can form a hydrogen bond or the like with the reactive site of the silanol group of the silane coupling agent or a site that can be chemically bonded by a covalent bond. In this inorganic filler, examples of the site that can be chemically bonded to the reactive site of the silane coupling agent include OH groups (hydroxyl groups, water molecules of water of water or crystallization, OH groups such as carboxy groups), amino groups, and SH groups.

By incorporating an inorganic filler into the chlorine-containing crosslinkable resin composition of the present invention, it is possible to improve strength and high-temperature properties while suppressing a decrease in flexibility.
Examples of inorganic fillers include metal hydrates such as aluminum hydroxide, magnesium hydroxide, calcium carbonate, magnesium carbonate, calcium silicate, magnesium silicate, calcium oxide, magnesium oxide, aluminum oxide, aluminum nitride, aluminum borate whiskers, hydrated aluminum silicate, hydrated magnesium silicate, basic magnesium carbonate, and compounds having hydroxyl groups or crystal water, such as hydrotalcite, and further, boron nitride, silica (crystalline silica, amorphous silica, etc.), carbon, clay, zinc oxide, tin oxide, titanium oxide, molybdenum oxide, antimony trioxide, silicone compounds, quartz, talc, zinc borate, white carbon, zinc borate, zinc hydroxystannate, and zinc stannate. Among these, the inorganic filler is preferably a metal hydrate (more preferably magnesium hydroxide), calcium carbonate, hydrotalcite, talc, clay, silica, or carbon, or a mixture thereof.

The inorganic filler is preferably in the form of particles, with an average particle size of preferably 0.2 to 10 μm, more preferably 0.3 to 8 μm, even more preferably 0.4 to 5 μm, and particularly preferably 0.4 to 3 μm. The average particle size is determined by dispersing the inorganic filler in alcohol or water and using an optical particle size measuring device such as a laser diffraction/scattering particle size distribution measuring device.

The inorganic filler may be one that has been surface-treated with a silane coupling agent or the like. Examples of silane coupling agent surface-treated metal hydrates include Kisuma 5L and Kisuma 5P (both trade names, magnesium hydroxide, manufactured by Kyowa Chemical Industry Co., Ltd., etc.). The amount of silane coupling agent used to surface-treat the inorganic filler is not particularly limited, but is, for example, 3 mass% or less.

(Other ingredients)
The chlorine-containing crosslinkable resin composition and the chlorine-containing crosslinkable resin composition may further contain the following components, if necessary.

- Silane coupling agent -
The silane coupling agent has a grafting reaction site (group or atom) that can undergo grafting reaction with a grafting reaction site of a chlorine-containing resin or the like in the presence of a radical generated by decomposition of an organic peroxide. Also, it has a hydrolyzable silyl group as a reaction site that can react with a chemically bondable site of an inorganic filler and can undergo silanol condensation. Any silane coupling agent of this type can be used without any particular limitation. Examples of such silane coupling agents include silane coupling agents used in conventional silane crosslinking methods.
Examples of the silane coupling agent include silane coupling agents having an unsaturated group, specifically, vinyl alkoxy silanes such as vinyl trimethoxy silane, vinyl triethoxy silane, vinyl tributoxy silane, vinyl dimethoxy ethoxy silane, vinyl dimethoxy butoxy silane, vinyl diethoxy butoxy silane, allyl trimethoxy silane, allyl triethoxy silane, vinyl triacetoxy silane, etc., and (meth) acryloxy alkoxy silanes such as methacryloxy propyl trimethoxy silane, methacryloxy propyl triethoxy silane, methacryloxy propyl methyl dimethoxy silane, etc. Among them, vinyl trimethoxy silane or vinyl triethoxy silane is particularly preferred.
The silane coupling agent may be used as it is, or may be used after being diluted with a solvent.

-Silanol condensation catalyst-
In the silane crosslinking method, the silanol condensation catalyst acts to promote a condensation reaction (promote) in the presence of moisture of the hydrolyzable silyl group of the silane coupling agent grafted to the chlorine-containing resin, etc. Based on the action of this silanol condensation catalyst, the chlorine-containing resin, etc. is crosslinked via the silane coupling agent.
Such silanol condensation catalysts are not particularly limited, and examples thereof include organotin compounds, metal soaps, platinum compounds, etc. Examples of organotin compounds include dibutyltin dilaurate, dioctyltin dilaurate, dibutyltin dioctiate, dibutyltin diacetate, and other organotin compounds.

- Other polymers -
In the present invention, polymers (including resins, elastomers, and rubbers) other than chlorine-containing resins and ethylene-carbon monoxide copolymers can also be used, such as polyolefin resins, fluororesins, fluororubbers, and various elastomers.

- Additive -
In the present invention, various additives generally used in resin compositions may be appropriately contained within the range that does not impair the effects of the present invention. Examples of such additives include crosslinking assistants, antioxidants, lubricants, metal deactivators, flame retardants (assistants), etc.
The antioxidant is not particularly limited, but examples thereof include amine antioxidants, phenol antioxidants, and sulfur antioxidants.
The crosslinking aid may be any commonly used one without any particular limitation, and may generally be a polyfunctional compound. Examples of the polyfunctional compound include (meth)acrylate compounds such as polypropylene glycol diacrylate and trimethylolpropane triacrylate, allyl compounds such as triallyl cyanurate (TAC) and triallyl isocyanurate (TAIC), maleimide compounds, and divinyl compounds.

(Content of each ingredient)
In the chlorine-containing crosslinkable resin composition of the present invention, the content (blending amount) of the ethylene-carbon monoxide copolymer is 5 to 60 parts by mass relative to 100 parts by mass of the chlorine-containing resin. When the content of the ethylene-carbon monoxide copolymer is within the above range, the composition is excellent in high-temperature properties while simultaneously achieving both flexibility and strength. The content of the ethylene-carbon monoxide copolymer is preferably 5 to 40 parts by mass, more preferably 10 to 40% by mass, relative to 100 parts by mass of the chlorine-containing resin, in that it is excellent in high-temperature properties while simultaneously achieving a good balance between flexibility and strength.

The plasticizer content is 5 to 40 parts by mass per 100 parts by mass of the chlorine-containing resin. If the plasticizer content is within the above range, flexibility and strength are compatible, while high-temperature properties are also excellent. The plasticizer content is preferably 10 to 30 parts by mass, and more preferably 20 to 30% by mass per 100 parts by mass of the chlorine-containing resin, in order to achieve a good balance between flexibility and strength, while also achieving excellent high-temperature properties.

The organic peroxide content is 0.01 to 5.0 parts by mass per 100 parts by mass of the chlorine-containing resin. The suitable organic peroxide content varies depending on the crosslinking method. For example, the organic peroxide content in the organic peroxide crosslinking method is preferably 0.05 to 3.0 parts by mass, and more preferably 0.05 to 2.0 parts by mass. On the other hand, the organic peroxide content in the silane crosslinking method is preferably 0.01 to 0.5 parts by mass, more preferably 0.05 to 0.2 parts by mass, and even more preferably 0.05 to 0.12 parts by mass.

The content of the inorganic filler is 0.5 to 100 parts by mass per 100 parts by mass of the chlorine-containing resin, in order to achieve both flexibility and strength, and is preferably 3 to 60 parts by mass, more preferably 5 to 40 parts by mass, and even more preferably 10 to 30 parts by mass, in order to achieve a good balance between flexibility and strength and further improve high-temperature properties.

In the chlorine-containing crosslinkable resin composition of the present invention, the contents of the other polymers and additives are not particularly limited and are determined appropriately. For example, the contents of the other polymers and additives can be 20% by mass or less and 10% by mass or less, respectively, relative to 100 parts by mass of the chlorine-containing resin.

In the chlorine-containing crosslinkable resin composition for silane crosslinking (chlorine-containing silane crosslinkable resin composition) of the present invention, the content of the silane coupling agent is 1 to 15 parts by mass per 100 parts by mass of the chlorine-containing resin. When the content of the silane coupling agent is within this range, the crosslinking reaction can be moderately advanced, and high strength and high-temperature properties can be achieved without impairing excellent flexibility. In addition, the silane coupling agent is adsorbed on the surface of the inorganic filler, and the silane coupling agent can be prevented from volatilizing during kneading, which is economical. Furthermore, it is possible to prevent the silane coupling agent that is not adsorbed from condensing, causing gel particles and roughness in the molded body, which deteriorates the appearance. The content of the silane coupling agent is preferably 2 to 8 parts by mass, and more preferably 2 to 6 parts by mass, in that it can achieve a good balance between flexibility and strength and further improve high-temperature properties.

In the chlorine-containing crosslinkable resin composition for silane crosslinking (chlorine-containing silane crosslinkable resin composition) of the present invention, the content of the silanol condensation catalyst is not particularly limited and may be appropriately set. For example, it is preferably 0.03 to 0.5 parts by mass, more preferably 0.03 to 0.2 parts by mass, and even more preferably 0.05 to 0.15 parts by mass, per 100 parts by mass of the chlorine-containing resin. When the content of the silanol condensation catalyst is set to 0.03 to 0.5 parts by mass, the crosslinking reaction can be moderately advanced, and high strength and high-temperature properties can be achieved without impairing excellent flexibility. In addition, the generation of gel particles during molding can be suppressed.

The content of each component in the chlorine-containing crosslinking resin composition of the present invention is basically the same as the content of each component in the chlorine-containing crosslinkable resin composition. However, the organic peroxide and the silanol condensation catalyst are usually decomposed and not present. The silane coupling agent is grafted to the chlorine-containing resin, etc. to form a crosslinked structure.

<Method for preparing chlorine-containing crosslinkable resin composition>
The chlorine-containing crosslinkable resin composition of the present invention can be prepared by mixing the above-mentioned components at a temperature lower than the decomposition temperature of the organic peroxide. The conditions for mixing the components are not particularly limited, but are usually set to a temperature lower than the decomposition temperature of the organic peroxide. In addition, the components may be mixed at once or sequentially. In particular, the chlorine-containing silane crosslinkable resin composition, which is a preferred form of the chlorine-containing crosslinkable resin composition (chlorine-containing crosslinkable resin composition for silane crosslinking), is preferably prepared in step (1) in the method for producing the silane-crosslinked chlorine-containing resin molded body of the present invention described later.

<Method for preparing chlorine-containing crosslinked resin composition>
The chlorine-containing crosslinkable resin composition of the present invention can be prepared by subjecting the chlorine-containing crosslinkable resin composition of the present invention to a crosslinking reaction treatment. The method of crosslinking reaction treatment is not particularly limited, and as described above, the organic peroxide crosslinking method and the silane crosslinking method can be applied, and the silane crosslinking method is preferred.
When the organic peroxide crosslinking method is applied, the crosslinking reaction treatment conditions include heat treatment at a temperature equal to or higher than the decomposition temperature of the organic peroxide. The heating method is not particularly limited, and includes appropriate heating devices such as vulcanization kettles and heating tubes. The heating temperature includes the heating temperature in step (a-2) described below. The heating time is not particularly limited. On the other hand, when the silane crosslinking method is applied, the conditions for the final crosslinking reaction treatment of the chlorine-containing silane crosslinkable resin composition, which is a preferred form of the chlorine-containing crosslinkable resin composition, include the conditions in step (3) described below.
By subjecting the chlorine-containing crosslinkable resin composition of the present invention to a crosslinking reaction, a chlorine-containing crosslinkable resin composition having a tensile strength of 10.0 MPa or more and a strength modulus ratio of 1.20 to 5.00 can be produced.
The chlorine-containing crosslinkable resin composition may be molded into a desired shape and dimensions before the crosslinking reaction. The molding method and conditions are not particularly limited, and examples of the molding method and conditions include those in the step (2) described below.

(Method for producing silane-crosslinked chlorine-containing resin molded product)
The silane-crosslinked chlorine-containing resin molded product, which is a suitable embodiment of the chlorine-containing crosslinked resin composition of the present invention, can be produced by the above-mentioned preparation method, but is preferably produced by a production method having the following steps (1), (2) and (3).
The method for producing a silane-crosslinked chlorine-containing resin molded article of the present invention (sometimes referred to as the molded article production method of the present invention) will be specifically described below.
The method for producing a molded article of the present invention is a method for producing a silane-crosslinked chlorine-containing resin molded article having a tensile strength of 10.0 MPa or more and a strength modulus ratio of 1.20 to 5.00, and includes the following steps (1), (2), and (3):

Step (1): 5 to 6 parts by mass of ethylene-carbon monoxide copolymer per 100 parts by mass of chlorine-containing resin
0 parts by weight, 5 to 40 parts by weight of a plasticizer, and 0.01 to 0.5 parts by weight of an organic peroxide.
0.5 to 100 parts by mass of inorganic filler, and 0.5 to 100 parts by mass of lanthanide generated from organic peroxide.
Silanes with grafting sites capable of undergoing grafting reactions in the presence of dicarbaromatic carbons.
1 to 15 parts by weight of a coupling agent and a silanol condensation catalyst are melt-mixed,
The radicals generated from the organic peroxides are used to form grafting reaction sites and chlorine-containing
By grafting the graftable portion of the resin, the salt
Step (2): A step of preparing a chlorine-containing silane-crosslinkable resin composition. Step (3): A step of contacting the obtained molded body with water to obtain a silane-crosslinked chlorine-containing resin molded body.
Process

The above step (1) includes the following steps depending on the use mode of the chlorine-containing resin.
That is, when the entire chlorine-containing resin is melt-mixed in the following step (a-2), step (1) includes the following steps (a-1), (a-2), and (c). On the other hand, when a part of the chlorine-containing resin is melt-mixed in the following step (a-2), step (1) includes the following steps (a-1), (a-2), (b), and (c).

Step (a-1): A step of mixing an inorganic filler and a silane coupling agent to prepare a mixture.
Step (a-2): Reacting the resulting mixture with all or a part of the chlorine-containing resin and ethylene-carbon monoxide
The copolymer and the plasticizer are mixed in the presence of an organic peroxide at a decomposition temperature of the organic peroxide.
The grafting reaction sites and the grafting reaction sites are melt-mixed at a temperature of 100° C. or higher.
By grafting the reactive sites, the silane masterbatch can be formed.
Step (b) of preparing a batch: Melt mix the remainder of the chlorine-containing resin and the silanol condensation catalyst to form a catalyst masterbatch.
Step (c) of preparing the batch: mixing the silane master batch and the silanol condensation catalyst or catalyst master batch.
A step of melt mixing to prepare a chlorine-containing silane crosslinkable resin composition.

In the above step (b), the resin to be mixed with the silanol condensation catalyst is sometimes called a carrier resin.
In addition, both steps (a-1) and (a-2) may be collectively referred to as step (a).

As described above, the method for producing a molded article of the present invention includes an embodiment in which a chlorine-containing resin is added to step (a-2) and used in step (b). In this case, 100 parts by mass of the chlorine-containing resin in step (1) is the total amount of the chlorine-containing resin mixed in step (a-2) and step (b).
Here, the chlorine-containing resin used in step (a-2) and step (b) is not particularly limited, and may be chlorinated polyethylene, polyvinyl chloride, or a mixture thereof. For example, at least chlorinated polyethylene that undergoes a grafting reaction may be used in step (a-2), and polyvinyl chloride that does not undergo a grafting reaction may be used as a carrier resin in step (b). Furthermore, the ethylene-carbon monoxide copolymer may be mixed in either step (a-2) or step (b), and is preferably mixed in step (a-2) because it is easily subjected to a grafting reaction, but a part of the ethylene-carbon monoxide copolymer may be mixed as a carrier resin in step (b).
When the remainder of the chlorine-containing resin is blended in step (b), the chlorine-containing resin is blended in an amount of preferably 70 to 95 mass%, more preferably 85 to 92 mass%, in step (a-2), and preferably 5 to 30 mass%, more preferably 8 to 15 mass%, in step (b). When a part of the ethylene-carbon monoxide copolymer is blended in step (b), the total blending amount of the chlorine-containing resin and the ethylene-carbon monoxide copolymer blended in step (b) can be in the same range as the blending amount of the chlorine-containing resin in step (b).

In the step (1), the components to be mixed and the amounts mixed (blended amounts) thereof are the same as the components and contents thereof in the above-mentioned chlorine-containing crosslinkable resin composition, and the reasons for setting the amounts mixed are also the same.
In particular, when the amount of the organic peroxide is set within the above range, in addition to the above reasons, the silane coupling agent can be effectively grafted to the chlorine-containing resin, etc., and the condensation reaction between unreacted silane coupling agents and the volatilization of the unreacted silane coupling agents can be suppressed. Also, the crosslinking reaction between chlorine-containing resins can be suppressed. As a result, it is possible to produce a silane-crosslinked chlorine-containing resin molded product with excellent appearance by suppressing the generation of bumps while imparting excellent high-temperature properties to the chlorine-containing crosslinked resin.
When a plasticizer is mixed in step (b), the amount of the plasticizer mixed is a part of the above-mentioned content, and is preferably 3 to 20 parts by mass, and more preferably 5 to 15 parts by mass, for example.

In carrying out step (1), steps (a-1) and (a-2) are carried out in sequence. That is, first, an inorganic filler and a silane coupling agent are mixed, and then the mixture obtained, all or a part of the chlorine-containing resin, an ethylene-carbon monoxide copolymer, a plasticizer, and an inorganic filler are melt-kneaded in the above-mentioned mixed amounts while being heated to a temperature equal to or higher than the decomposition temperature of the organic peroxide, thereby inducing the above-mentioned grafting reaction to prepare a silane master batch (Silane MB).
In the present invention, the order of mixing when "melting and mixing the mixture with all or a part of the chlorine-containing resin, the ethylene-carbon monoxide copolymer, and the plasticizer" is not particularly limited, and means that each component may be mixed in any order. That is, the order of mixing in step (a-2) is not particularly limited. For example, the mixture, the chlorine-containing resin, the ethylene-carbon monoxide copolymer, the plasticizer, and the remaining components may be melt-mixed at once, or the chlorine-containing resin and the plasticizer may be mixed in advance in the same manner as the dry processing mixing in step (a-1) described later (preferably dry blending of powders) and then mixed with the above mixture, etc., or further, the mixture, the chlorine-containing resin, and the plasticizer may be dry-processed and mixed (preferably dry blending of powders), and then the obtained mixture and the remaining components, such as ethylene-carbon monoxide copolymer, other components, etc. may be melt-mixed. In addition, the method of mixing the chlorine-containing resin is not particularly limited. For example, a chlorine-containing resin that has been mixed and prepared in advance may be used, or each component may be mixed separately.

In step (1), first, the inorganic filler and the silane coupling agent are mixed using an appropriate mixing device to prepare a mixture (step (a-1)). The premixed silane coupling agent is present so as to surround the surface of the inorganic filler, and it is considered that a part or all of it is adsorbed or bonded to the inorganic filler. This allows a well-balanced formation of a silane coupling agent that is weakly bonded or adsorbed to the inorganic filler and a silane coupling agent that is strongly bonded or adsorbed to the inorganic filler. Here, examples of the weak bond between the silane coupling agent and the inorganic filler include interactions due to hydrogen bonds, interactions between ions, partial charges or dipoles, and effects due to adsorption. Examples of the strong bond with the inorganic filler include chemical bonds with sites on the inorganic filler surface that can be chemically bonded. In addition, the above step (a-1) can reduce the volatilization of the silane coupling agent during subsequent melt mixing, and can also prevent condensation of the silane coupling agent that is not adsorbed or bonded to the inorganic filler, which makes melt kneading difficult.

The method of premixing the inorganic filler and the silane coupling agent is not particularly limited, but examples of mixing methods include wet processing and dry processing. Specifically, the inorganic filler and the silane coupling agent are mixed by dry or wet processing for several minutes to several hours at a temperature below the decomposition temperature of the organic peroxide, preferably 10 to 60°C, more preferably around room temperature (20 to 25°C). Dry processing in which the silane coupling agent is added to the inorganic filler, preferably dried inorganic filler, with or without heating and mixed is more preferred. In step (a-1), the chlorine-containing resin and ethylene-carbon monoxide copolymer may be mixed as long as the temperature is maintained below the decomposition temperature.

In the method for producing a molded article of the present invention, the mixture of inorganic filler and silane coupling agent obtained in step (a-1), all or a part of the chlorine-containing resin, and the remaining components not mixed in step (a-1) are melt-mixed in the presence of an organic peroxide while being heated to a temperature equal to or higher than the decomposition temperature of the organic peroxide (step (a-2)). By step (a-2), excessive crosslinking reactions between the chlorine-containing resins and between the ethylene-carbon monoxide copolymers can be prevented, and a crosslinked molded article with excellent appearance can be obtained.
By the melt mixing in step (a-2), the radicals generated from the organic peroxide cause a graft reaction between the graft reaction site of the silane coupling agent and the graft reaction site of the chlorine-containing resin or the like. As a result, a silane graft resin in which the silane coupling agent is covalently bonded to the chlorine-containing resin or the like is synthesized, and a silane MB containing this silane graft resin is prepared. In step (a-2), at least the following can be mentioned as an embodiment in which the silane coupling agent is grafted to the chlorine-containing resin or the like. That is, the silane coupling agent bonded or adsorbed to the inorganic filler by a weak bond is detached from the inorganic filler and grafted to the chlorine-containing resin or the like. The crosslinked structure formed in this embodiment does not incorporate the inorganic filler, and is usually a crosslinked structure via a silanol condensate between the silane coupling agents. In addition, the silane coupling agent bonded or adsorbed to the inorganic filler by a strong bond is grafted to the chlorine-containing resin or the like while maintaining the bond with the inorganic filler. The crosslinked structure formed in this manner incorporates the inorganic filler, and is a crosslinked structure starting from the inorganic filler via the silane coupling agent bonded thereto. In this process, the silane coupling agent may also undergo a grafting reaction with the ethylene-carbon monoxide copolymer while maintaining the bonded or adsorbed state with the inorganic filler.

In step (a-2), the temperature at which the above components are melt-mixed (also referred to as melt-kneading or kneading) is equal to or higher than the decomposition temperature of the organic peroxide, preferably equal to or higher than the decomposition temperature of the organic peroxide + (25 to 110) ° C, more preferably equal to or higher than 150 to 230 ° C. At the above mixing temperature, the above components melt, the organic peroxide decomposes, and the necessary silane grafting reaction proceeds sufficiently in step (a-2). Here, the decomposition temperature of the organic peroxide, which is the basis of the melt-mixing temperature, is the temperature in a normal pressure (about 0.1 MPa) environment. Other conditions can be set as appropriate. For example, the mixing time is set as appropriate in the range of 3 to 40 minutes. The decomposition temperature of the organic peroxide is preferably equal to or higher than the temperature at which the chlorine-containing resin melts.
The mixing method is not particularly limited as long as it is a method commonly used for rubber, plastics, etc. As a kneading device, a single screw extruder, a twin screw extruder, a roll, a Banbury mixer, various kneaders, etc. are used. In terms of dispersibility of the chlorine-containing resin, etc., and stability of the crosslinking reaction, a closed type mixer such as a Banbury mixer or various kneaders is preferred.

The organic peroxide and the ethylene-carbon monoxide copolymer may each be present during the melt mixing in the above step (a-2), i.e., when the mixture obtained in step (a-1) is melt mixed with the chlorine-containing resin. These components may be mixed, for example, in step (a-1), in step (a-2), or further mixed as a carrier resin in step (b). The organic peroxide is preferably mixed in step (a-1), and the ethylene-carbon monoxide copolymer is preferably mixed in step (a-2).
It is sufficient that a part of the plasticizer is present during the melt mixing in the above step (a-2), and the plasticizer may be mixed in either step (a-1) or step (a-2). The plasticizer is preferably mixed in step (a-2), but the remainder may be mixed in step (b) described below.

In steps (a-1) and (a-2), and particularly in step (a-2), it is preferable to melt-mix the above-mentioned components without substantially mixing in a silanol condensation catalyst. This makes it possible to suppress the condensation reaction of the silane coupling agent. Here, "substantially not mixed" does not mean to exclude the silanol condensation catalyst that is inevitably present, but means that it may be present to the extent that the above-mentioned problems due to silanol condensation of the silane coupling agent do not occur. For example, in step (a-2), the silanol condensation catalyst may be present in an amount of 0.01 parts by mass or less per 100 parts by mass of the chlorine-containing resin.

In this way, step (a), which consists of steps (a-1) and (a-2), is carried out to graft the silane coupling agent with the chlorine-containing resin and, if necessary, with the ethylene-carbon monoxide copolymer to prepare Silane MB. Silane MB is a mixture containing a silane graft resin in which the silane coupling agent has been grafted to the chlorine-containing resin, etc., to an extent that it can be molded in step (2) described below.

In the molded body manufacturing method of the present invention, if a portion of the chlorine-containing resin is melt-mixed in step (a-2), then step (b) is carried out in which the remainder of the chlorine-containing resin and the silanol condensation catalyst are melt-mixed to prepare a catalyst master batch (catalyst MB). Therefore, if the entire chlorine-containing resin is melt-mixed in step (a-2), step (b) does not need to be carried out.

The mixing ratio of the remainder of the chlorine-containing resin as the carrier resin and the silanol condensation catalyst is not particularly limited, but is preferably set so as to satisfy the above-mentioned blending amount in step (1).
The mixing may be performed by any method that can achieve uniform mixing, including mixing performed under molten chlorine-containing resin (melt mixing). Melt mixing can be performed in the same manner as in the melt mixing in the above step (a-2). For example, the mixing temperature can be appropriately set to a temperature equal to or higher than the melting temperature of the chlorine-containing resin component, and is preferably 120 to 200°C, more preferably 140 to 180°C. Other conditions, such as the mixing time, can be appropriately set.

In step (b), instead of or in addition to the remainder of the chlorine-containing resin, another resin can be used as a carrier resin in an appropriate amount. That is, in step (b), the remainder of the chlorine-containing resin when a part of the chlorine-containing resin is melt-mixed in step (a-2), or a resin other than the chlorine-containing resin used in step (a-2), and the silanol condensation catalyst may be melt-mixed to prepare a catalyst master batch.
In step (b), an inorganic filler or a plasticizer can also be mixed.
In the case where a chlorine-containing resin and a plasticizer are used in the step (b), it is preferable to first premix the chlorine-containing resin and the plasticizer under the dry processing mixing conditions of the above step (a-1), and then melt-mix the obtained premix with the silanol condensation catalyst and, if appropriate, the remaining components.
The catalyst MB thus prepared is a (molten) mixture of the silanol condensation catalyst and the carrier resin, optionally with added fillers or plasticizers.

In the method for producing a molded article of the present invention, the next step (c) is carried out in which the silane MB and the silanol condensation catalyst or catalyst MB are melt-mixed to prepare a chlorine-containing crosslinkable resin composition.
The mixing method may be any mixing method, and is basically the same as the melt mixing in step (a-2). Mixing is performed at a temperature at least at which the chlorine-containing resin melts. The melt mixing temperature is appropriately selected according to the melting temperature of the chlorine-containing resin or the carrier resin, and is, for example, preferably 80 to 250°C, more preferably 100 to 240°C, and even more preferably 120 to 200°C. Other conditions, such as the mixing time, can be appropriately set.
In step (c), in order to avoid the silanol condensation reaction, it is preferred that the mixture of silane MB and silanol condensation catalyst is not kept at high temperature for a long period of time.
In carrying out this step (c), the silane master batch and the silanol condensation catalyst or catalyst MB may be dry-blended and then melt-mixed. The conditions for dry blending are not particularly limited, but examples thereof include the dry mixing conditions of the above step (a-1).

In this manner, steps (a) to (c) (step (1)) are carried out to prepare a chlorine-containing silane crosslinkable resin composition. This chlorine-containing silane crosslinkable resin composition contains the silane graft resin, the chlorine-containing resin, the ethylene-carbon monoxide copolymer, the plasticizer, the inorganic filler, the silanol condensation catalyst, etc.
This chlorine-containing silane crosslinkable resin composition contains silane graft resins with different crosslinking methods. In this silane graft resin, the reactive site of the silane coupling agent capable of silanol condensation may be bonded or adsorbed to an inorganic filler, but is not silanol condensed as described below. Therefore, the silane graft resin includes at least a silane graft resin in which the silane coupling agent bonded or adsorbed to an inorganic filler is grafted to a chlorine-containing resin, etc., and a silane graft resin in which the silane coupling agent not bonded or adsorbed to an inorganic filler is grafted to a chlorine-containing resin, etc.
As described above, the silane graft resin is an uncrosslinked body in which the silane coupling agent is not condensed with silanol. In practice, when melt-mixed in step (c), partial crosslinking is inevitable, but the obtained chlorine-containing silane crosslinkable resin composition maintains at least the injection moldability in the injection molding in step (2).

In step (1), steps (a) to (c) can be carried out simultaneously or consecutively.

In step (1), the additives, particularly the antioxidant, may be mixed in any step, but it is preferable to mix them into the catalyst MB.

In the method for producing a molded article of the present invention, a step (2) is then carried out in which the chlorine-containing silane crosslinkable resin composition obtained in the step (1) is molded to obtain a molded article. The molded article obtained in the step (2) is an uncrosslinked molded article in which the silane coupling agent has not undergone a silanol condensation reaction.
This molding step (2) may be any method capable of molding the chlorine-containing silane crosslinkable resin composition, such as extrusion molding using an extruder, extrusion molding using an injection molding machine, or molding using other molding machines. When the heat-resistant product of the present invention is a wiring material, extrusion molding is preferred in terms of productivity and the ability to be co-extruded with a conductor. Extrusion molding can be performed using a general-purpose extrusion molding machine. The molding temperature is appropriately set depending on various conditions such as the type of resin and the molding speed (take-off speed), and is preferably set to, for example, 150 to 200°C.
The molding in step (2) can be carried out simultaneously with or consecutively to the mixing in step (c). That is, during melt molding, for example during extrusion molding, or immediately before that, the silane master batch (molten mixture) obtained in step (a-2) and the silanol condensation catalyst or the catalyst master batch (mixture) obtained in step (b) are melt-mixed as molding raw materials. For example, a series of steps can be adopted in which a mixture of the silane master batch and the silanol condensation catalyst obtained in step (a-2) is melt-mixed in a coating device, and then extrusion-coated on the outer peripheral surface of a conductor or the like, and molded into a desired shape.

In this way, a molded article of the chlorine-containing silane crosslinkable resin composition is obtained. Like the chlorine-containing silane crosslinkable resin composition, this molded article is in an uncrosslinked or partially crosslinked state that retains moldability in step (2), although some crosslinking is unavoidable. Therefore, by carrying out step (3), this molded article becomes a crosslinked or final crosslinked silane-crosslinked chlorine-containing resin molded article.

In the method for producing a molded article of the present invention, the molded article obtained in step (2) is then contacted with water in step (3). This causes the silanol-condensable reactive sites (hydrolyzable silyl groups) of the silane coupling agent to be hydrolyzed to silanol groups, which then condense with other silanol groups (hydroxyl groups) to cause a crosslinking reaction. In this way, a silane-crosslinked chlorine-containing resin molded article in which the silane coupling agent is crosslinked by silanol condensation can be obtained.
The treatment in step (3) itself can be carried out by a normal method. The condensation reaction between silane coupling agents proceeds by simply leaving the silane coupling agents at room temperature, for example, at a temperature of about 20 to 25°C. Therefore, in step (3), it is not necessary to actively bring the molded body into contact with water. In order to promote this crosslinking reaction, the molded body can also be actively brought into contact with moisture. For example, a method of actively bringing the molded body into contact with water, such as exposure to a high humidity atmosphere, immersion in warm water, immersion in a heat and humidity bath, or exposure to high-temperature water vapor, can be adopted. In addition, pressure may be applied at this time to allow moisture to penetrate into the interior.

In this way, a silane-crosslinked chlorine-containing resin molded body is produced from the chlorine-containing silane crosslinkable resin composition. This silane-crosslinked chlorine-containing resin molded body contains a silane crosslinked resin in which a chlorine-containing resin and an ethylene-carbon monoxide copolymer are condensed via a siloxane bond. The silane-crosslinked chlorine-containing resin molded body also contains an inorganic filler, and this inorganic filler may be bonded to a silane coupling agent of the silane crosslinked resin. Therefore, this silane crosslinked resin contains at least a silane crosslinked resin in which a plurality of chlorine-containing resins, etc. are bonded or adsorbed to the inorganic filler by the silane coupling agent, and bonded (crosslinked) via the inorganic filler and the silane coupling agent, and a silane crosslinked resin in which the reactive sites of the silane coupling agent of the chlorine-containing resins, etc. are hydrolyzed and undergo a silanol condensation reaction with each other, and crosslinked via the silane coupling agent.

As described above, the molded article manufacturing method of the present invention uses the above-mentioned chlorine-containing resin, ethylene-carbon monoxide copolymer, plasticizer, and inorganic filler in combination with each component essential for the silane crosslinking method in the silane crosslinking method having a series of the above steps (1) to (3). Therefore, in the series of steps, particularly in step (1), the above-mentioned chlorine-containing resin, ethylene-carbon monoxide copolymer, plasticizer, and inorganic filler exhibit the above-mentioned functions while a predetermined grafting reaction proceeds, and a chlorine-containing silane crosslinkable resin composition is prepared. Then, by subjecting this chlorine-containing silane crosslinkable resin composition to a silanol condensation reaction after molding to form a silane crosslinked structure via a siloxane bond, the characteristics or functions of each component are effectively expressed, and a silane-crosslinked chlorine-containing resin molded article (molded article of a chlorine-containing crosslinkable resin composition) that exhibits excellent flexibility while exhibiting high strength and maintains high strength even at high temperatures can be produced.
In this way, the molded article manufacturing method of the present invention can produce a silane-crosslinked chlorine-containing resin molded article that exhibits excellent flexibility while exhibiting high strength and that maintains high strength even at high temperatures, using a simple silane crosslinking method (which allows crosslinking without heating), that is, a method that does not require the conventional crosslinking step, and is energy-saving and highly productive.

<Cabtyre cable>
The cabtyre cable of the present invention has a conductor, an insulating layer covering the outer periphery of the conductor, and a sheath covering the outer periphery of the insulating layer, the sheath being formed of a chlorine-containing crosslinkable resin composition obtained by subjecting a chlorine-containing crosslinkable resin composition to a crosslinking reaction treatment, and having a tensile strength of 10.0 MPa or more and a strength modulus ratio of 1.20 to 5.00 in a tensile test described below. The sheath is preferably formed of a silane-crosslinked chlorine-containing resin molded product produced by the method for producing a silane-crosslinked chlorine-containing resin molded product of the present invention.
In the present invention, coating the outer periphery includes both an embodiment in which the outer periphery is directly coated and an embodiment in which the outer periphery is indirectly coated via another layer or member. Directly coating the outer periphery means that a predetermined layer is provided in contact with the outer periphery surface of the conductor, in other words, that no other layer or structure is present between the outer periphery surface and the predetermined layer.
In the cab-tire cable, the conductor and insulating layer covered with the sheath include, for example, an insulated wire or an optical fiber. The configurations of the cab-tire cable, the insulated wire, and the optical fiber are not particularly limited except that the sheath is formed of a chlorine-containing crosslinked resin composition, and may be the same as those of a normal cab-tire cable, the insulated wire, and the optical fiber.

The conductor may be one or more. When there are more than one, it is preferable that they are twisted or arranged to form an assembly. The outer diameter of the conductor can be set appropriately depending on the application. The conductor constituting the insulated electric wire can be any conductor that is normally used for insulated electric wires without any particular restrictions, and can be a single wire or twisted wire of soft copper. In addition to bare wires of copper, copper alloy, aluminum, aluminum alloy, etc., tin-plated conductors or enamel-coated conductors can also be used. The conductor (fiber strand) constituting the optical fiber can be any conductor that is normally used for optical fiber without any particular restrictions, and can be glass, quartz, plastic, etc.

The insulating layer covers the outer periphery of the conductor. When an assembly of a plurality of conductors is used, the insulating layer may cover the outer periphery of the integrated assembly, and does not need to cover the outer periphery of each conductor forming the assembly. The insulating layer may be disposed so as to have a partial space between the insulating layer and the conductor.
The insulating layer may be one that is normally used in cab-tire cables (insulated electric wires, optical fibers). For example, the material forming the insulating layer is not particularly limited, and examples thereof include polyolefin resins such as polyethylene, polypropylene, ethylene-α-olefin copolymer, ethylene-vinyl acetate copolymer, ethylene-(meth)acrylic acid copolymer, and ethylene-alkyl (meth)acrylate copolymer, or crosslinked cured products thereof. The insulating layer may be a single layer or multiple layers. The thickness of the insulating layer may be appropriately determined depending on the application, etc., and may be, for example, 0.4 to 6.0 mm.
In a cabtyre cable, the insulated electric wire or optical fiber arranged in the sheath may be one or more. When multiple insulated electric wires or optical fibers are arranged, the multiple insulated electric wires or optical fibers may be twisted together or arranged side by side (one insulated electric wire or optical fiber, or an assembly of multiple insulated electric wires or optical fibers, is sometimes called a cable core).

The sheath covers the outer periphery of the insulating layer. When an assembly of a plurality of insulated electric wires or optical fibers is used, the sheath may cover the outer periphery of the integrated assembly, and it is not necessary to cover the insulating layer of each insulated electric wire or each optical fiber forming the assembly. The sheath may be a single layer or multiple layers. The sheath may be disposed so as to have a partial space between it and the insulating layer. The thickness of the sheath may be appropriately determined depending on the application, etc., and may be, for example, 0.4 to 9.0 mm.
A release agent layer containing talc or the like may be provided between the insulating layer and the sheath.

As described above, the cabtyre cable of the present invention has a sheath formed from the chlorine-containing crosslinked resin composition of the present invention, and therefore has excellent flexibility and high strength while also exhibiting excellent high-temperature characteristics.
Cab-tire cables are sometimes classified into cab-tire cables and cab-tire cords based on the rated voltage, but the cab-tire cable of the present invention includes both of them. The cab-tire cable of the present invention is preferably a cab-tire cable in the above-mentioned category.

BEST MODE FOR CARRYING OUT THE PRESENT DISCLOSURE A preferred embodiment of the cab-tyre cable of the present invention will be described with reference to the drawings.
One embodiment of the cabtyre cable of the present invention, the end view of which is shown in Figure 1, is a cabtyre cable 10A having one insulated wire consisting of one conductor 1A and an insulating layer 2A that directly covers the outer periphery of the conductor 1A, and a sheath 3A that directly covers the insulating layer 2A.
Another embodiment of the cab-tire cable of the present invention, the end view of which is shown in FIG. 2, is similar to the cab-tire cable shown in FIG. 1, except that the cable core has three insulated wires each consisting of one conductor 1B and an insulating layer 2B that directly covers the outer periphery of the conductor 1B.

<Manufacturing method of cab-tyre cable>
The cab-tire cable of the present invention can be produced by a conventional method, for example, by covering a cable core with the chlorine-containing crosslinkable resin composition of the present invention, and is preferably produced by utilizing the method for producing a silane-crosslinked chlorine-containing resin molded article of the present invention. Specifically, in the method for producing a silane-crosslinked chlorine-containing resin molded article of the present invention, the chlorine-containing silane-crosslinkable resin composition obtained in step (1) is molded into a tubular shape on the outer circumferential surface of a cable core in step (2), and then step (3) is carried out to produce the cable. The molding in step (2) is preferably extrusion coating molding, and a molding method in which the cable core and the chlorine-containing silane-crosslinkable resin composition are co-extruded is usually adopted.
In the above-mentioned method for producing a cab-tire cable, by using a conductor (fiber strand) instead of an insulated electric wire or an optical fiber as a cable core, it is possible to produce various wiring materials such as an insulated electric wire or an optical fiber having an insulating layer made of a silane-crosslinked chlorine-containing resin molded product.

The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these.
In Tables 2-1 to 2-4 (collectively referred to as Table 2), the numerical values relating to the blending amount (content) of each example are in parts by mass unless otherwise specified. In addition, a blank for each component means that the blending amount of the corresponding component is 0 parts by mass.
The column "Crosslinkable composition" in Table 2 shows the content of specific components in each chlorine-containing crosslinkable resin composition.

Details of the compounds used in the examples and comparative examples are shown in Table 1 and below.
<Chlorine-containing resin>

(Measurement of Chlorine Content)
The chlorine content of each chlorinated polyethylene was measured in accordance with JIS K 7229. The amount of chloride ions was determined by potentiometric titration.

(Determination of crystallinity of chlorinated polyethylene)
For each chlorinated polyethylene, a DSC curve was obtained by raising the temperature at a rate of 10° C./min using a DSC (differential scanning calorimeter) (DSC-60 Plus (trade name), manufactured by Shimadzu Corporation). At the melting point observed at that time, the heat of fusion (J/g) was measured, and a value of less than 5 J/g was judged to be non-crystalline, a value of 5 J/g or more but less than 50 J/g to be semi-crystalline, and a value of 50 J/g or more to be crystalline. The melting point in the DSC curve was taken as the temperature at the start of an endothermic reaction, and the heat of fusion was calculated from the area of the portion that changed from the baseline of the DSC curve when an endothermic reaction occurred.

<Ethylene-carbon monoxide copolymer>
Ethylene-butyl acrylate-carbon monoxide copolymer: Elbaloy HP662 (trade name), manufactured by DuPont Ethylene-vinyl acetate-carbon monoxide copolymer: Elbaloy 742 (trade name), manufactured by DuPont <Ethylene-vinyl acetate copolymer>
Ethylene-vinyl acetate copolymer: Evaflex EV150 (product name), ethylene content 67% by mass, vinyl acetate content 33% by mass, manufactured by Dow Mitsui Polychemicals <Plasticizer>
Diisononyl phthalate: DINP, manufactured by J-Plus Co., Ltd. <Inorganic filler>
Fumed silica: KONASIL K-200D (product name), manufactured by OCI Calcium carbonate: SOFTON 1200 (product name), manufactured by Bihoku Funka Kogyo Co., Ltd. Hydrotalcite: DHT-4A-2 (product name), manufactured by Bihoku Funka Kogyo Co., Ltd. <Silane coupling agent>
KBM-1003: Product name, vinyltrimethoxysilane, manufactured by Shin-Etsu Chemical Co., Ltd. <Organic peroxide>
Perhexa 25B: Trade name, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, decomposition temperature 149°C, manufactured by NOF Corporation Percumyl D40: Trade name, dicumyl peroxide, decomposition temperature 145°C, manufactured by NOF Corporation <Cross-linking aid>
TAIC: Triallyl isocyanurate, manufactured by Mitsubishi Chemical Corporation <antioxidant>
Irganox 1076: Trade name, octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, manufactured by BASF Corporation <Silanol condensation catalyst>
Adeka STAB OT-1: Product name, dioctyltin dilaurate, manufactured by ADEKA Corporation

(Example 1 and Comparative Examples 1 and 2)
In the present examples and comparative examples, a chlorine-containing crosslinkable resin composition for organic peroxide crosslinking was prepared as the chlorine-containing crosslinkable resin composition, which was extrusion-molded onto the outer peripheral surface of a conductor, and then a crosslinking reaction treatment was carried out by an organic peroxide crosslinking method to produce an insulated wire having a coating layer formed thereon.
First, the components shown in the "Compound" column of Tables 2-1 and 2-3 were charged in a 10L Henschel mixer manufactured by Toyo Seiki Seisakusho Co., Ltd. in the ratios (parts by mass) shown in each table, and mixed at room temperature (25°C) for 10 minutes to obtain a mixture. Next, the obtained mixture was melt-mixed (kneading temperature 120°C, kneading time 10 minutes) using a 2L Banbury mixer manufactured by Nippon Roll Co., Ltd., and then pelletized to obtain each chlorine-containing crosslinkable resin composition for organic peroxide crosslinking.
The obtained chlorine-containing crosslinkable resin composition for organic peroxide crosslinking was introduced into an extruder (compression section screw temperature 110° C., head temperature 120° C.) equipped with a screw having an L/D (ratio of effective screw length L to diameter D) of 24 and a screw diameter of 30 mm. While melt-mixing the chlorine-containing crosslinkable resin composition for organic peroxide crosslinking in the extruder, it was extrusion-coated on the outer peripheral surface of a 1/0.8TA conductor to a thickness of 0.8 mm, to obtain a coated conductor with an outer diameter of 2.4 mm.
Next, the coated conductor was placed in a vulcanizing kettle at 140° C. and 6 MPa for 2 hours. In this manner, the chlorine-containing crosslinkable resin composition for organic peroxide crosslinking placed on the outer peripheral surface of the conductor was subjected to a crosslinking reaction treatment, thereby producing each insulated wire having an insulating layer made of a tubular molded body of the chlorine-containing crosslinkable resin composition on the outer peripheral surface of the conductor.

(Examples 2 to 20 and Comparative Examples 3 to 13)
In the present examples and comparative examples, a preferred embodiment of a chlorine-containing silane crosslinkable resin composition was prepared as a chlorine-containing crosslinkable resin composition (chlorine-containing crosslinkable resin composition for silane crosslinking), and this was extrusion-molded onto the outer peripheral surface of a conductor, followed by a crosslinking reaction treatment by a silanol condensation reaction to produce an insulated wire having a coating layer formed thereon.
In Examples 2 to 20 and Comparative Examples 3 to 13, a part of polyvinyl chloride or chlorinated polyethylene 1 among the chlorine-containing resins (specifically, the mass proportion shown in the "Step (b) Catalyst MB" column in Table 2) was used as a carrier resin for catalyst MB.
First, the inorganic filler, organic peroxide, and silane coupling agent among the components shown in the "Silane MB" column of Table 2 were charged into a 10 L Henschel mixer manufactured by Toyo Seiki Seisakusho Co., Ltd. in the mass ratio shown in the "Silane MB" column of Table 2, and mixed at room temperature (25°C) for 10 minutes to obtain a powder mixture (step (a-1)).
Next, the powder mixture thus obtained, the chlorine-containing resin, ethylene-carbon monoxide copolymer, plasticizer and antioxidant shown in the "Silane MB" column of Table 2 were charged into a 2L Banbury mixer manufactured by Nippon Roll Co., Ltd. in the mass ratio shown in the "Silane MB" column of Table 2, and kneaded for 10 minutes at a temperature equal to or higher than the decomposition temperature of the organic peroxide, specifically at 190°C, and then discharged at a material discharge temperature of 200°C to obtain Silane MB (step (a-2)).

Meanwhile, the chlorine-containing resin as the carrier resin, the silanol condensation catalyst, the plasticizer, and the antioxidant shown in the "Catalyst MB" column of Table 2 were melt-mixed at 180 to 190°C in a Banbury mixer in the mass ratio shown in the "Catalyst MB" column of Table 2, and discharged at a material discharge temperature of 180 to 190°C to obtain catalyst MB (step (b)).

The Silane MB and Catalyst MB thus obtained were placed in a closed ribbon blender and dry blended at room temperature (25°C) for 5 minutes to obtain a dry blend. At this time, the mixing ratio of Silane MB and Catalyst MB was the mass ratio shown in the "Step (a) Silane MB" and "Step (b) Catalyst MB" columns of Table 2, and the mass ratio shown in the "Crosslinkable composition" column of Table 2. For example, in Example 2, the mixing amount of the chlorine-containing resin in Silane MB was 90 parts by mass, and the mixing amount of the chlorine-containing resin in Catalyst MB was 10 parts by mass.

The obtained dry blend was then introduced into an extruder (compression section screw temperature 160° C., head temperature 180° C.) equipped with a screw having a screw diameter of 30 mm and an L/D (ratio of effective screw length L to diameter D) of 24. The dry blend was melt-mixed in the extruder to prepare a chlorine-containing silane crosslinkable resin composition (step (c)), which was then extrusion-coated onto the outer peripheral surface of a 1/0.8TA conductor with a thickness of 0.8 mm to obtain a coated conductor with an outer diameter of 2.4 mm (step (2)).
This coated conductor (molded product of the chlorine-containing silane-crosslinkable resin composition) was left to stand in an atmosphere at a temperature of 40° C. and a humidity of 95% for 24 hours (step (3)).
In this manner, the molded article of the chlorine-containing silane-crosslinkable resin composition placed on the outer peripheral surface of the conductor was subjected to a silanol condensation reaction to produce an insulated wire having an insulating layer made of a tubular silane-crosslinked chlorine-containing resin molded article on the outer peripheral surface of the conductor.

The produced insulated wires were subjected to the following test methods to evaluate the characteristics.
<Test 1: Tensile test>
Using tubular test pieces (inner diameter 0.8 mm, outer diameter 2.4 mm) prepared by extracting the conductor from each insulated wire, the tensile strength (MPa), 100% modulus (MPa), and tensile elongation (%) were measured under conditions of a gauge length of 20 mm and a tensile speed of 200 mm/min according to JIS C 3005. The strength modulus ratio was calculated by dividing the tensile strength thus obtained by the 100% modulus.
The tensile strength is one of the characteristics for evaluating the strength of a chlorine-containing crosslinked resin composition (silane-crosslinked chlorine-containing resin molded article), and in this test, a strength of 10.0 MPa or more is acceptable, and 12.0 MPa or more is preferable.
The 100% modulus is one of the characteristics for evaluating the flexibility of a chlorine-containing crosslinked resin composition (silane-crosslinked chlorine-containing resin molded article), and in this test, a practical value is 2.0 MPa or more, and a range of 3.0 MPa or more and 11.0 MPa or less is preferable.
The tensile elongation is a reference test, and is preferably 150% or more.
A strength-modulus ratio of 1.20 to 5.00 is acceptable.

<Test 2: Winding test>
Each of the produced insulated wires was wound around a mandrel having a diameter of 2.4 mm in an environment of 25° C., and the possibility of bending (wrapping state) and the degree of crushing of the wire were evaluated.

(Can it be bent?)
The insulated wire was cut to a length of 300 mm, and the test wire with 250 g weights attached to both ends was wound around a horizontally placed mandrel (the test wire was hung with the center of its length placed perpendicular to the mandrel on the mandrel), and left to stand for 5 minutes. The weights on both ends were then increased to 500 g, and the test wire was left to stand for another 5 minutes.
The bendability test is one of the characteristics for evaluating the flexibility of a chlorine-containing crosslinked resin composition (silane-crosslinked chlorine-containing resin molded product), and the condition of the end of a test wire hung on a mandrel was evaluated according to the following evaluation criteria. The pass level for this test is a rating of "B" or higher.

A: When the weight is 250g, the test wire is wound around the mandrel, and both ends of the wire drop due to gravity. The test wire is bent in an inverted U shape around the mandrel, and both ends become parallel (excellent).
B: Both ends of the test wire are parallel when the weight is 500 g (good)
E: Both ends of the test wire were not parallel even with a weight of 500 g (failed)

(Deformation of the electric wire)
The outer diameter of the central portion (center in the length direction) of the insulated electric wire cut to a length of 300 mm was measured in advance in the direction in which it contacted the mandrel, and then the above-mentioned test for [whether or not it can be bent] was carried out. After attaching a 500 g weight and leaving it for 5 minutes, the outer diameter of the central portion was measured again, and the rate of change in the outer diameter before and after winding (the ratio of the outer diameter after winding to the outer diameter before winding) was calculated.
The wire crushing test is one of the characteristics for evaluating the strength of the chlorine-containing crosslinked resin composition (silane-crosslinked chlorine-containing resin molded product), and was evaluated by applying the rate of change in outer diameter to the following evaluation criteria. The pass level for this test is a rating of "B" or higher.

A: 97.0% or more (excellent)
B: 95.0% or more and less than 97.0% (good)
E: Less than 95.0% (failed)

<Test 3: High temperature crushing test>
Each of the manufactured insulated wires was placed in a thermostatic chamber of a thermostatic chamber-equipped tensile tester (thermostatic chamber: TCR2L type, tensile tester: AGS-5kNX, manufactured by Shimadzu Corporation) with the conductor still attached, and stored at 75°C for 30 minutes. Thereafter, in a 75°C environment, the insulated wire was compressed using an autograph equipped with a blade, and the maximum force (unit: Newton [N]) applied until the blade penetrated the insulating layer of the insulated wire and reached the conductor was measured. A blade with a tip diameter of 500 μm was used, and the compression speed was 2 mm/min.
The high-temperature crush test is a characteristic for evaluating the high-temperature properties of the chlorine-containing crosslinked resin composition (silane-crosslinked chlorine-containing resin molded product), and the maximum force measured was evaluated according to the following evaluation criteria. The pass level for this test is a rating of "D" or higher.

A: 40N or more (extremely excellent)
B: 30N or more but less than 40N (excellent)
C: 22N or more and less than 30N (good)
D: 18N or more but less than 22N (usable)
E: Less than 18N (failed)

The chlorine-containing crosslinkable resin compositions of Comparative Examples 1 to 11, which do not satisfy the component contents specified in the present invention, cannot form chlorine-containing crosslinkable resin compositions that have both excellent flexibility and high strength and also excellent high-temperature properties. Also, the chlorine-containing crosslinkable resin compositions of Comparative Examples 12 and 13, which satisfy the component contents specified in the present invention but do not satisfy the tensile strength or strength modulus ratio when crosslinked, cannot achieve both excellent flexibility and high strength, or are inferior in high-temperature properties.
In contrast, the chlorine-containing crosslinkable resin compositions of Examples 1 to 20, which satisfy the component contents specified in the present invention and also satisfy the tensile strength or strength modulus ratio when crosslinked, can form chlorine-containing crosslinkable resin compositions that have both excellent flexibility and high strength and also excellent high-temperature properties.

10A, 10B Cabtyre cable 1A, 1B Conductor 2A, 2B Insulation layer 3A, 3B Sheath

Claims (16)

A chlorine-containing crosslinkable resin composition comprising, relative to 100 parts by mass of a chlorine-containing resin, 5 to 60 parts by mass of an ethylene-carbon monoxide copolymer, 5 to 40 parts by mass of a plasticizer, 0.01 to 5.0 parts by mass of an organic peroxide, and 0.5 to 100 parts by mass of an inorganic filler,
the chlorine-containing resin comprises chlorinated polyethylene and polyvinyl chloride;
the ethylene-carbon monoxide copolymer comprises at least one of an ethylene-vinyl acetate-carbon monoxide copolymer and an ethylene-(meth)acrylic acid ester-carbon monoxide copolymer;
The chlorine-containing crosslinkable resin composition has a tensile strength of 10.0 MPa or more when crosslinked, and the value obtained by dividing the tensile strength by the 100% modulus is 1.20 to 5.00. The chlorine-containing crosslinkable resin composition according to claim 1, further comprising, per 100 parts by mass of the chlorine-containing resin, 1 to 15 parts by mass of a silane coupling agent having a grafting reaction site capable of undergoing a grafting reaction in the presence of radicals generated from the organic peroxide, and a silanol condensation catalyst. The chlorine-containing crosslinkable resin composition according to claim 2, wherein the ethylene-carbon monoxide copolymer is an ethylene-(meth)acrylic acid ester-carbon monoxide copolymer. The chlorine-containing crosslinkable resin composition according to claim 2, wherein the chlorine-containing resin contains 50 to 90% by mass of the chlorinated polyethylene and the polyvinyl chloride, and contains 10 to 50% by mass of the polyvinyl chloride. The chlorine-containing crosslinkable resin composition according to claim 2, wherein the chlorinated polyethylene comprises an amorphous chlorinated polyethylene. The chlorine-containing crosslinkable resin composition according to claim 5, wherein the content of the non-crystalline chlorinated polyethylene in the chlorinated polyethylene is 80 mass%. The chlorine-containing crosslinkable resin composition according to claim 2, wherein the chlorinated polyethylene contains chlorinated polyethylene having a chlorine content of 30% or more and less than 38%. The chlorine-containing crosslinkable resin composition according to claim 2, wherein the chlorinated polyethylene includes chlorinated polyethylene having a chlorine content of 30% or more and less than 38% and chlorinated polyethylene having a chlorine content of 38% or more and less than 42%. The chlorine-containing crosslinkable resin composition according to claim 2, wherein the chlorine-containing resin comprises 30 to 50 mass% of chlorinated polyethylene having a chlorine content of 30% or more and less than 38%, 10 to 30 mass% of chlorinated polyethylene having a chlorine content of 38% or more and less than 42%, and 10 to 50 mass% of polyvinyl chloride. A chlorine-containing crosslinkable resin composition obtained by subjecting the chlorine-containing crosslinkable resin composition according to any one of claims 1 to 9 to a crosslinking reaction treatment,
A chlorine-containing crosslinked resin composition having a tensile strength of 10.0 MPa or more, and a value obtained by dividing the tensile strength by a 100% modulus of 1.20 to 5.00. A cabtyre cable having a sheath made of the chlorine-containing crosslinked resin composition according to claim 10. A method for producing a silane-crosslinked chlorine-containing resin molded article having a tensile strength of 10.0 MPa or more and a value obtained by dividing the tensile strength by a 100% modulus of 1.20 to 5.00, comprising the steps (1), (2) and (3) below:
Step (1): 5 to 6 parts by mass of ethylene-carbon monoxide copolymer per 100 parts by mass of chlorine-containing resin
0 parts by weight, 5 to 40 parts by weight of a plasticizer, and 0.01 to 0.5 parts by weight of an organic peroxide.
parts by mass, 0.5 to 100 parts by mass of an inorganic filler, and
The grafting reaction site is capable of undergoing a grafting reaction in the presence of a radical.
1 to 15 parts by mass of a run coupling agent and a silanol condensation catalyst are melt-mixed.
The graft reaction portion is then reacted with the radicals generated from the organic peroxide.
and a grafting reaction between the grafting site of the chlorine-containing resin and the grafting site of the chlorine-containing resin.
Step (2): The chlorine-containing silane-crosslinkable resin composition is molded to obtain a molded body. Step (3): The molded body is contacted with water to obtain a silane-crosslinked chlorine-containing resin molded body.

the chlorine-containing resin comprises chlorinated polyethylene and polyvinyl chloride;
the ethylene-carbon monoxide copolymer comprises at least one of an ethylene-vinyl acetate-carbon monoxide copolymer and an ethylene-(meth)acrylic acid ester-carbon monoxide copolymer;
In the step (1), when the whole of the chlorine-containing resin is melt-mixed in the following step (a-2), the step (1) comprises the following steps (a-1), (a-2), and (c); and in the step (a-2), when a part of the chlorine-containing resin is melt-mixed, the step (1) comprises the following steps (a-1), (a-2), (b), and (c).

Step (a-1): The inorganic filler and the silane coupling agent are mixed to prepare a mixture.
Step (a-2): mixing the mixture, all or a part of the chlorine-containing resin, and ethylene-carbon monoxide.
The copolymer and the plasticizer are mixed in the presence of the organic peroxide.
The grafting reaction site is melt-mixed at a temperature equal to or higher than the decomposition temperature of
and the graftable portion,
Step (b): preparing a silane master batch by melt-mixing the remainder of the chlorine-containing resin and the silanol condensation catalyst to form a catalyst master batch.
Step (c) of preparing a master batch: The silane master batch and the silanol condensation catalyst or the catalyst master batch are mixed.
The chlorine-containing silane crosslinkable resin composition is prepared by melt-mixing the above batch.
Process The method according to claim 12, wherein the chlorine-containing resin is such that, out of a total of 100% by mass of the chlorinated polyethylene and the polyvinyl chloride, the content of the chlorinated polyethylene is 50 to 90% by mass and the content of the polyvinyl chloride is 10 to 50% by mass. The method according to claim 12, wherein the chlorinated polyethylene contains 80% by mass or more of amorphous chlorinated polyethylene. The method of claim 12, wherein the chlorine-containing resin comprises 30 to 50 mass% of chlorinated polyethylene having a chlorine content of 30% or more and less than 38%, 10 to 30 mass% of chlorinated polyethylene having a chlorine content of 38% or more and less than 42%, and 10 to 50 mass% of polyvinyl chloride. A cabtyre cable having a sheath made of a silane-crosslinked chlorine-containing resin molded product produced by the method according to any one of claims 12 to 15.

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