JP6916106B2 - Catalyst composition for silane cross-linking, silane cross-linking resin composition and wiring material - Google Patents

Description

The present invention relates to a silane crosslinking catalyst composition, a silane crosslinkable resin composition, and a wiring material.

Wiring materials such as insulated wires, tubes, cables, cords, optical fiber core wires or optical fiber cords (optical fiber cables) have, for example, a coating layer made of polyolefin resin. By cross-linking the polyolefin resin forming the coating layer, the heat resistance of the coating layer can be improved.
As a method for cross-linking a polyolefin resin, a silane cross-linking method having advantages such as not requiring special equipment is known. In the silane cross-linking method of a polyolefin resin, generally, first, in the presence of an organic peroxide, a silane coupling agent having a hydrolyzable silyl group and an unsaturated group is grafted onto the polyolefin resin to silane. Prepare a graft polyolefin resin. Then, the obtained silane graft polyolefin resin is brought into contact with water in the presence of a silanol condensation catalyst to condense the hydrolyzable silyl group. In this way, the polyolefin resin can be crosslinked with silane. As an example of applying the silane cross-linking method, for example, Patent Document 1 describes an inorganic filler, a silane coupling agent, and an organic peroxide in which a resin component obtained by mixing a polyolefin resin and a maleic anhydride resin is surface-treated with a silane coupling agent. A method has been proposed in which the oxide and the cross-linking catalyst are sufficiently melt-kneaded with a kneader and then molded with a uniaxial extruder.

Japanese Unexamined Patent Publication No. 2001-101928

Wiring materials are required to have characteristics according to their application. For example, wiring materials used for heat-resistant parts of vehicles such as automobiles can maintain not only heat resistance that is not easily deformed even at high temperatures, but also characteristics that can be maintained even in continuous or intermittent high-temperature environments ( High aging resistance (which can withstand long-term use) is required.
In general, high aging resistance can be achieved by forming the coating layer of the wiring material with a crosslinked product of a resin composition containing a high content of an antioxidant.

By the way, in the above-mentioned silane cross-linking method, there is a method using a silane graft resin and a silane cross-linking catalyst composition (catalyst master batch) containing a silanol condensation catalyst.
When an anti-aging agent such as a benzoimidazole-based anti-aging agent or a hydrazine-based heavy metal inactivating agent is applied to this silane cross-linking method, particularly in an increased amount, the polyolefin resin is applied by a usual method (electron beam cross-linking or excessive). It was found that a problem that does not exist in the method of cross-linking a resin by (chemical cross-linking using an oxide, etc.) becomes apparent. When an anti-aging agent is used in the silane cross-linking method, it is contained in the catalyst master batch (also referred to as catalyst MB) in that the dispersibility of the anti-aging agent is enhanced and the silane grafting reaction is not inhibited. However, when a catalyst masterbatch containing an antioxidant is used, a benzoimidazole-based antioxidant and a hydrazine-based heavy metal inactivating agent are used to melt-mix with the carrier resin used in the preparation of the catalyst masterbatch. Occasionally, gas is generated, and the gas remains in the obtained catalyst masterbatch to form bubbles (voids) (becomes porous (sponge-like)), which causes a problem of foaming. As a result, air bubbles remain in the crosslinked product obtained by cross-linking the silane graft resin using this catalyst masterbatch, which causes poor appearance. Moreover, when the content of the anti-aging agent is increased, the problem of foaming becomes remarkable. Further, when the crosslinked product of the silane graft resin is secondarily processed, there arises a problem that the crosslinked product foams at a high temperature and impairs the required characteristics of the product.

The present invention solves the above problems and can be prepared by suppressing foaming even when a benzoimidazole-based antiaging agent and further a hydrazine-based heavy metal inactivating agent are used, and silane using a silane graft resin. An object of the present invention is to provide a silane cross-linking catalyst composition capable of imparting excellent heat resistance, aging resistance and appearance to a cross-linked product of the obtained silane graft resin by using it in a cross-linking method. Further, according to the present invention, by using this silane cross-linking catalyst composition, a silane cross-linking resin composition exhibiting excellent moldability, which can form a cross-linked product of a silane cross-linking resin while suppressing appearance defects and generation of lumps, can be obtained. It is an object of the present invention to provide a wiring material using a silane crosslinkable resin composition, which has excellent heat resistance, aging resistance and appearance, and is hard to foam even during secondary processing.

The present inventors used a carrier resin containing a polyolefin resin in a silane cross-linking catalyst composition that promotes silanol condensation (silane cross-linking) of a silane graft resin, and used the carrier resin as a silanol condensation catalyst and benzoimidazole-based aging. An inhibitor and a hydrazine-based heavy metal inactivating agent (also referred to as a hydrazine-based antiaging agent) are blended in specific amounts, and the melt flow rate (fluidity) of the obtained silane cross-linking catalyst composition is set. By doing so, foaming during preparation as described above can be suppressed, the silane crosslinkable resin composition using this silane crosslinking catalyst composition exhibits excellent moldability, and further, for this silane crosslinking. It has been found that the wiring material using the catalyst composition exhibits excellent heat resistance, aging resistance and appearance, and can suppress foaming during secondary processing. Based on this finding, the present inventors have further studied and came to the present invention.

That is, the subject of the present invention has been achieved by the following means.
[1]
Silane coupling agent having a hydrolyzable silyl group is a silane crosslinking catalyst composition used in silane crosslinking grafting reaction silane-grafted resin,
15 to 30 parts by mass of a benzoimidazole-based antioxidant, 5 to 25 parts by mass of a hydrazine-based heavy metal inactivating agent, and 0.05 to 5 parts by mass of a silanol condensation catalyst are added to 100 parts by mass of a carrier resin containing a polyolefin resin. A catalyst composition for silane cross-linking, which is contained and has a melt flow rate of 0.1 to 7 g / 10 min at 190 ° C. and 2.16 kg.
[2]
The catalyst composition for silane cross-linking according to [1], which contains 30 parts by mass or less of a phenolic antiaging agent.
[3]
The catalyst composition for silane cross-linking according to [1] or [2], wherein the melt flow rate at 190 ° C. and 2.16 kg is 0.5 to 7 g / 10 min.
[4]
The catalyst composition for silane cross-linking according to any one of [1] to [3], wherein the carrier resin contains 20% by mass or more of a styrene-based elastomer.
[5]
It is a melt mixture of the silane cross-linking catalyst composition according to any one of [1] to [4] and the silane graft resin composition containing a base resin, and the base resin is a hydrolyzable silyl group. A silane crosslinkable resin composition containing a silane graft resin obtained by grafting a silane coupling agent having a silane coupling agent.
[6]
The silane crosslinkable resin composition according to [5], wherein the base resin contains 10% by mass or more of a styrene-based elastomer.
[7]
The silane crosslinkable resin composition according to [5] or [6], which contains 10 to 400 parts by mass of an inorganic filler with respect to a total of 100 parts by mass of the carrier resin and the base resin of the catalyst composition for silane crosslinking. ..
[8]
A wiring material having a coating layer made of a cured product of the silane crosslinkable resin composition according to any one of [5] to [7].
[9]
The wiring material according to [8], which is a heat-resistant electric wire or cable.

The numerical range represented by using "~" in the present specification means a range including the numerical values before and after "~" as the lower limit value and the upper limit value.

The present invention can be prepared by suppressing foaming even if it contains a benzimidazole-based antiaging agent and further a hydrazine-based heavy metal inactivating agent, and by using it for cross-linking of a silane graft resin, silane It is possible to provide a silane cross-linking catalyst composition capable of imparting excellent heat resistance, aging resistance and appearance to a cross-linked body of a graft resin. Further, in the present invention, by using this silane cross-linking catalyst composition, a silane cross-linking resin composition exhibiting excellent moldability, which can form a cross-linked product of a silane cross-linking resin while suppressing appearance defects and generation of lumps, can be obtained. Can be provided. Furthermore, the present invention can provide a wiring material using a silane crosslinkable resin composition, which has excellent heat resistance, aging resistance and appearance, and is less likely to foam even during secondary processing.

[Catalyst composition for silane cross-linking]
The catalyst composition for silane cross-linking of the present invention contains a carrier resin, a benzimidazole-based antioxidant, a hydrazine-based heavy metal inactivating agent, and a silanol condensation catalyst in a specific mass ratio, and has a melt flow rate in a specific range. ..
This catalyst composition for silane cross-linking can be prepared by suppressing foaming due to gas or the like generated during preparation (during melting and mixing).

The catalyst composition for silane cross-linking of the present invention is used in the silane cross-linking method in combination with a silane graft resin obtained by grafting a silane coupling agent having a hydrolyzable silyl group.
In the present invention, the combination of the silane cross-linking catalyst composition and the silane graft resin means that the silane cross-linking catalyst composition and the silane graft resin can be used in combination, and other components are further used in combination. Also includes that. That is, in addition to the embodiment in which the silane cross-linking catalyst composition and the silane graft resin are used in combination, the embodiment in which the silane cross-linking catalyst composition and the silane graft resin composition are used in combination is included.
Further, using the catalyst composition for silane cross-linking in the silane cross-linking method means using the silane graft resin in the method of silane cross-linking. That is, in addition to the mode used for cross-linking the silane graft resin (forming a crosslinked body of the silane graft resin), the mode used for curing the silane graft resin composition (forming a cured product of the silane cross-linkable resin composition) is used. Include.

When the catalyst composition for silane cross-linking of the present invention and the silane graft resin are used in combination, foaming can be suppressed when preparing (melting and mixing) the silane cross-linking resin composition and / or molding. In addition, it is possible to obtain a silane crosslinkable resin composition having excellent moldability such that poor appearance at the time of molding and formation of lumps are suppressed. Furthermore, when used in the silane cross-linking method in combination with a silane graft resin, a cross-linked product of a silane graft resin (silane cross-linking resin composition) which suppresses foaming and has excellent heat resistance, aging resistance, and appearance. Can form a cured product). By utilizing this property, it is possible to manufacture a wiring material having a coating layer containing a crosslinked body of a silane graft resin having excellent properties.
In the present invention, a cured product of the silane crosslinkable resin composition of the present invention (a silane crosslinked cured product obtained by molding the silane crosslinkable resin composition of the present invention and then crosslinking with silane) is referred to as a silane crosslinked resin molded product. be.

Each component of the catalyst composition for silane cross-linking of the present invention will be described.

<Carrier resin>
The carrier resin contains a polyolefin resin. The carrier resin may further contain a mineral oil.

− Polyolefin resin −
The polyolefin resin is not particularly limited as long as it is a resin made of a polymer obtained by homopolymerizing or copolymerizing a compound having an ethylenically unsaturated bond, and is known as conventionally used in a resin composition. You can use things. The polyolefin resin is preferably a resin that is mixed (compatible) with a silane graft resin described later.
Examples of the resin component included in the polyolefin resin include a polyethylene resin, a polypropylene resin, an ethylene-α-olefin copolymer resin, a polyolefin copolymer resin having an acid copolymer component or an acid ester copolymer component, and these. Examples thereof include various resins such as rubber or elastomer. Examples of the rubber or elastomer include ethylene-α-olefin copolymer rubber, styrene-based elastomer, and ethylene acrylic rubber.
In the present invention, the polyolefin resin or the resin component may be used alone or in combination of two or more.

(Polyethylene resin)
The polyethylene resin may be a resin of a polymer containing an ethylene component, and is a homopolymer composed only of ethylene, or a copolymer of ethylene and α-olefin (preferably 5 mol% or less) (corresponding to polypropylene). Excludes), as well as resins made of copolymers of ethylene and non-olefins (preferably 1 mol% or less) having only carbon, oxygen and hydrogen atoms as functional groups. As the above-mentioned α-olephyrene and non-olefin, known ones conventionally used as a copolymerization component of polyethylene are used without particular limitation.
Examples of the polyethylene resin that can be used in the present invention include high density polyethylene (HDPE), low density polyethylene (LDPE), ultra high molecular weight polyethylene (UHMW-PE), linear low density polyethylene (LLDPE) or ultra low density polyethylene (VLDPE). ). Among them, high-density polyethylene, low-density polyethylene, and linear low-density polyethylene are preferable, and linear low-density polyethylene or low-density polyethylene is more preferable. One type of polyethylene resin may be used alone, or two or more types may be used in combination.

Melt flow rate of polyethylene resin (hereinafter sometimes referred to as MFR. In the present invention, MFR is a value measured in accordance with JIS K 7210 under the conditions of a temperature of 190 ° C. and a weight of 2.16 kg. ) Is preferably 0.05 to 10 g / 10 min, more preferably 0.5 to 5.0 g / 10 min. By setting the melt flow rate to 0.05 to 10 g / 10 min, it is possible to suppress foaming due to gas or the like generated from the mixture with the benzimidazole-based antiaging agent, and a silane crosslinked resin molded product having an excellent appearance can be obtained. ..

(Polypropylene resin)
The polypropylene resin may be a polymer containing a propylene component as a main component, and a resin such as a propylene homopolymer (homopolypropylene resin), an ethylene-propylene random copolymer, or an ethylene-propylene block copolymer is used. can do.
The ethylene-propylene random copolymer means that the content of the ethylene component is about 1 to 10% by mass, and the ethylene component is randomly incorporated into the propylene chain. Further, the ethylene-propylene block copolymer refers to one having an ethylene or ethylene-propylene rubber (EPR) component content of about 5 to 20% by mass, and the ethylene or EPR component is independently present in the propylene component. It is a sea-island structure. Particularly preferred as the polypropylene resin is an ethylene-propylene random copolymer resin in terms of appearance. The ethylene component content is a value measured according to the method described in ASTM D3900.

The melt flow rate of polypropylene resin (meaning the value measured under the conditions of a temperature of 230 ° C. and a weight of 2.16 kg according to JIS K 7210) is preferably 0.05 to 25 g / 10 min, and is 0.1 to 0.1. 10 g / 10 min is more preferable. By setting the melt flow rate to 0.05 to 25 g / 10 min, it is possible to suppress foaming due to gas or the like generated from the mixture with the benzimidazole-based antiaging agent, and a silane crosslinked resin molded product having an excellent appearance can be obtained. .. In addition, the thermal deformation characteristics may be improved.

(Ethylene-α-olefin copolymer resin)
The ethylene-α-olefin copolymer resin preferably includes a resin obtained from a copolymer of ethylene and an α-olefin having 3 to 12 carbon atoms (excluding those corresponding to the above-mentioned polyethylene and polypropylene). The α-olefin is not particularly limited, and examples thereof include 1-propylene, 1-butene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-decene or 1-dodecene. The ethylene-α-olefin copolymer may be used alone or in combination of two or more.

The melt flow rate of the ethylene-α-olefin copolymer resin is preferably 0.05 to 10 g / 10 min, more preferably 0.5 to 5 g / 10 min. By setting the melt flow rate to 0.05 to 10 g / 10 min, it is possible to suppress foaming due to gas or the like generated from the mixture with the benzimidazole-based antiaging agent, and a silane crosslinked resin molded product having an excellent appearance can be obtained. .. In addition, it may be possible to obtain a silane crosslinked resin molded product having superior tensile strength as compared with polyethylene resin.

(Ethylene-α-olefin copolymer rubber)
The ethylene-α-olefin copolymer rubber is not particularly limited as long as it is a rubber composed of a copolymer of ethylene and the α-olefin. For example, ethylene-propylene copolymer rubber (EP rubber (EPM)), and examples thereof include a rubber-like copolymer of ethylene and propylene. Here, the ethylene-propylene copolymer rubber means a rubber having an ethylene component content of about 40 to 75% by mass. The ethylene component content in the ethylene-propylene copolymer rubber is preferably 50 to 75% by mass, more preferably 55 to 70% by mass. The ethylene component content is a value measured according to the method described in ASTM D3900.

Ethylene-α-olefin copolymer rubber is an ethylene-propylene terpolymer having a repeating unit having an unsaturated group as a third component other than ethylene and α-olefin (propylene) (for example, ethylene, α-olefin and diene). Includes ternary copolymers (EPDM)). In the present invention, either one or both of EPM and EPDM may be used as the ethylene-α-olefin copolymer rubber.

The melt flow rate of the ethylene-α-olefin copolymer rubber is preferably 0.01 to 2 g / 10 min, more preferably 0.1 to 1.5 g / 10 min. By setting the melt flow rate to 0.01 to 2 g / 10 min, foaming due to gas or the like generated from the mixture with the benzimidazole antiaging agent can be suppressed, and a silane crosslinked resin molded product having an excellent appearance can be obtained. .. In addition, flexibility may be imparted to the silane crosslinked resin molded product.

(Polyolefin copolymer resin having an acid copolymer component or an acid ester copolymer component)
The acid copolymerization component or acid ester copolymerization component in the polyolefin copolymer resin having an acid copolymerization component or acid ester copolymerization component is not particularly limited, but is not particularly limited, but is not particularly limited, and carboxylic acid compounds such as (meth) acrylic acid and acetic acid. Examples thereof include acid ester compounds such as vinyl and alkyl (meth) acrylate. Here, the alkyl group of the alkyl (meth) acrylate is preferably one having 1 to 12 carbon atoms. Examples of the polyolefin copolymer resin having an acid copolymer component or an acid ester copolymer component include ethylene-vinyl acetate copolymer (EVA), ethylene- (meth) acrylic acid copolymer, and ethylene- (meth) acrylic. Examples thereof include alkyl acid copolymers. The polyolefin copolymer having an acid copolymer component or an acid ester copolymer component may be used alone or in combination of two or more.

The melt flow rate of the polyolefin copolymer resin having an acid copolymer component or an acid ester copolymer component is preferably 0.05 to 10 g / 10 min, more preferably 1 to 3 g / 10 min. By setting the melt flow rate to 0.05 to 10 g / 10 min, it is possible to suppress foaming due to gas or the like generated from the mixture with the benzimidazole-based antiaging agent, and a silane crosslinked resin molded product having an excellent appearance can be obtained. .. In addition, it may be able to strongly bond with the inorganic filler and impart high tensile strength and abrasion resistance to the silane crosslinked resin molded product.

(Ethylene acrylic rubber)
The ethylene acrylic rubber is not particularly limited, but as a constituent component, a rubber elastic body composed of a copolymer obtained by copolymerizing alkyl acrylate such as ethyl acrylate and butyl acrylate with ethylene is preferable. Particularly preferably, a rubber made of each copolymer such as a binary copolymer with ethylene and a ternary copolymer obtained by copolymerizing an unsaturated hydrocarbon having a carboxy group in the side chain is particularly preferably used. Can be done. Examples of the ethylene acrylic rubber made of the binary copolymer include Baymac DP and Baymac DLS. Examples of the ethylene acrylic rubber made of the ternary copolymer include Baymac G, Baymac HG, Baymac LS, and Baymac GLS (trade names, all manufactured by Mitsui and DuPont Polychemical).

The melt flow rate of the ethylene acrylic rubber is preferably 0.01 to 2 g / 10 min, more preferably 0.1 to 1 g / 10 min. By setting the melt flow rate to 0.01 to 2 g / 10 min, foaming due to gas or the like generated from the mixture with the benzimidazole antiaging agent can be suppressed, and a silane crosslinked resin molded product having an excellent appearance can be obtained. .. Further, oil resistance and flame retardancy can be imparted to the silane crosslinked resin molded product.

(Styrene-based elastomer)
The styrene-based elastomer refers to an elastomer containing an aromatic vinyl compound in the molecule. Examples of such styrene-based elastomers include block copolymers and random copolymers of conjugated diene compounds and aromatic vinyl compounds, and hydrogenated products thereof. Examples of such styrene-based elastomers include styrene-ethylene-butylene-styrene block copolymer (SEBS), styrene-isoprene-styrene block copolymer (SIS), and hydride styrene-butadiene-styrene block copolymer. (SBS hydride), styrene-ethylene-ethylene-propylene-styrene block copolymer (SEEPS), styrene-ethylene-propylene-styrene block copolymer (SEPS), styrene-butadiene rubber (SBR), hydride SIS, Examples thereof include styrene-hydride rubber hydride (HSBR). The styrene-based elastomer may be used alone or in combination of two or more.
By containing the styrene-based elastomer, foaming during secondary processing of the silane crosslinked resin molded product can be effectively suppressed. In particular, when a styrene-based elastomer is used in combination with another polyolefin resin, foaming during secondary processing can be suppressed more effectively. This inhibitory effect is particularly high when a high molecular weight (molecular weight: about 100,000 to 500,000) styrene-based elastomer is used. The reason is considered to be that the fluidity of the carrier resin can be effectively reduced.

The polyolefin resin, that is, the polymer may be acid-modified. The acid used for acid denaturation is not particularly limited, and examples thereof include unsaturated carboxylic acids that are usually used.

− Mineral oil −
The mineral oil used in the present invention is a mixed oil containing three oils, an oil having an aromatic ring, an oil having a naphthen ring, and an oil having a paraffin chain. In paraffin-based oil, the carbon number (CP) of the paraffin chain is, for example, 50% or more and less than 75% of the total carbon number of the aromatic ring, the naphthen ring, and the paraffin chain, and the carbon number (CN) of the naphthen chain is 20 or more and less than 40%, and the carbon number of the aromatic ring (CA) is 3 or more and less than 10%. The naphthenic oil has a CN of 40 or more and less than 60%, a CP of 30% or more and less than 50%, and a CA of 8% or more and less than 16% with respect to the total carbon number. Is 16% or more.
As the mineral oil (softening material for rubber), paraffin-based oil or naphthen-based oil can be used, and paraffin-based oil is preferable in terms of mechanical strength.
The mineral oil preferably has a dynamic viscosity at 40 ° C. of 20 to 500 cSt, a pour point of -10 to -15 ° C., and a flash point (COC) of 180 to 300 ° C.
Examples of the mineral oil include "Diana process oil" (trade name, manufactured by Idemitsu Kosan Co., Ltd.) and "Cosmo Neutral" (trade name, manufactured by Cosmo Oil Lubricants Co., Ltd.).

The total content of the polyolefin resin in 100% by mass of the carrier resin is preferably 60 to 100% by mass.

In the present invention, the content of each of the resin components in the carrier resin is appropriately set within a range satisfying the content of the polyolefin resin in the carrier resin, and can be set to, for example, the following content.
The content of the polyethylene resin is preferably 0 to 100% by mass, more preferably 40 to 100% by mass, based on 100% by mass of the carrier resin.
The content of the polypropylene resin is preferably 0 to 100% by mass based on 100% by mass of the carrier resin, and the silane cross-linking catalyst composition or the silane cross-linking resin composition can be adjusted to have a fluidity suitable for molding and suppresses appearance defects. From the viewpoint of being able to do so, 20 to 60% by mass is more preferable.
The content of the ethylene-α-olefin copolymer resin is preferably 0 to 100% by mass, more preferably 20 to 100% by mass, still more preferably 40 to 100% by mass, based on 100% by mass of the carrier resin.
The content of the ethylene-α-olefin copolymer rubber is preferably 0 to 100% by mass, more preferably 5 to 50% by mass, based on 100% by mass of the carrier resin.
The content of the polyolefin copolymer having an acid copolymer component or an acid ester copolymer component is preferably 0 to 100% by mass based on 100% by mass of the carrier resin. Although it does not impair the action and effect of the present invention, 0 to 50% by mass is more preferable, and 5 to 30% by mass is particularly preferable, from the viewpoint of suppressing adhesion of the catalyst MB to a metal part such as an apparatus.
The content of ethylene acrylic rubber is preferably 0 to 100% by mass, more preferably 5 to 50% by mass, based on 100% by mass of the carrier resin.
The content of the styrene-based elastomer is preferably 20% by mass or more, more preferably 25 to 50% by mass, based on 100% by mass of the carrier resin.

The content of the mineral oil is preferably 0 to 40% by mass, more preferably 10 to 40% by mass, based on 100% by mass of the carrier resin. When the content of the mineral oil is within the above range, the generation of lumps can be suppressed and the bleed-out of the mineral oil can be prevented. As a result, a silane crosslinked resin molded product having an excellent appearance can be produced.

From the viewpoint of suppressing the generation of gel lumps during extrusion molding, it is also preferable to use a combination of low-density polyethylene, a styrene-based elastomer, and a mineral oil, and the content of each component in this case is set in the above range. Although it is possible, it is preferable to set it to 40 to 80% by mass of low density polyethylene, 10 to 40% by mass of styrene elastomer, and 10 to 40% by mass of mineral oil in 100% by mass of the carrier resin.

<Silanol condensation catalyst>
The silanol condensation catalyst has a function of causing a silanol condensation reaction (promoting) of a hydrolyzable silyl group derived from a silane coupling agent in a silane graft resin described later in the presence of water. Based on the action of this silanol condensation catalyst, the resins forming the silane graft resin are crosslinked with each other via a silane coupling agent. Therefore, the obtained silane crosslinked resin molded product is excellent in heat resistance and, if necessary, strength.
The silanol condensation catalyst used in the present invention is not particularly limited, and examples thereof include an organotin compound, a metallic soap, and a platinum compound. Specifically, organotin compounds such as dibutyltin dilaurate, dioctyltin dilaurate, dibutyltin dioctate, and dibutyltin diacetate, zinc stearate, lead stearate, barium stearate, calcium stearate, sodium stearate, lead naphthenate, and sulfate. Examples include lead, zinc sulfate, and organic platinum compounds.
One type of silanol condensation catalyst may be used, or two or more types may be used.

The content of the silanol condensation catalyst in the catalyst composition for silane cross-linking is 0.05 to 5 parts by mass, more preferably 0.3 to 2 parts by mass with respect to 100 parts by mass of the carrier resin. By setting the content of the silanol condensation catalyst in the above range, it can be suitably used for cross-linking the silane graft resin. However, the content of the silanol condensation catalyst is appropriately determined in consideration of the mixing ratio with the silane graft resin composition used in combination, the required characteristics of the silane crosslinked resin molded product, and the like. Details will be described later, but the content of the silanol condensation catalyst in the silane cross-linking catalyst composition is adjusted so as to be the mass ratio described later with respect to the total amount of the carrier resin and the base resin contained in the silane graft resin composition. , The mixing ratio of the silane cross-linking catalyst composition is preferably set.

<Anti-aging agent>
The catalyst composition for silane cross-linking of the present invention contains 15 to 50 parts by mass of a benzimidazole-based antioxidant and 25 parts by mass or less of a hydrazine-based heavy metal inactivating agent with respect to 100 parts by mass of the carrier resin. The catalyst composition for silane cross-linking of the present invention may further contain a phenolic antiaging agent. In the present invention, the benzimidazole-based antiaging agent, the hydrazine-based heavy metal inactivating agent, and the phenol-based antiaging agent may be collectively referred to as "anti-aging agent".
The anti-aging agent has a function of suppressing deterioration of the silane crosslinked resin molded product during long-term use and enhancing aging resistance.

The benzimidazole-based antiaging agent is not particularly limited as long as it is usually used in the field of wiring materials and the like. For example, a zinc salt of 2-mercaptobenzimidazole (Nocrack MBZ, trade name, 1,3-dihydro-2H-benzimidazol-2-thione / 0.5 zinc, manufactured by Ouchi Shinko Kagaku Kogyo Co., Ltd.) and the like can be mentioned. The benzimidazole-based antiaging agent may be one kind or two or more kinds.

The hydrazine-based heavy metal inactivating agent is not particularly limited as long as it is usually used in the field of wiring materials and the like. For example, 1,2-bis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionyl] hydrazine (ADEKA STAB CDA-10 (trade name), manufactured by ADEKA), 1,2-bis [ 3- (4-Hydroxy-3,5-di-tert-butylphenyl) propionyl] hydrazine (Irganox MD1024 (trade name), manufactured by BASF) and the like can be mentioned. The hydrazine-based heavy metal inactivating agent may be one kind or two or more kinds.

The phenolic anti-aging agent is not particularly limited as long as it is usually used in the field of wiring materials and the like. For example, a hindered phenolic anti-aging agent is preferable, for example, octadecyl-3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate (Irganox 1076 (trade name), manufactured by BASF) or penta. Ellisritol tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate (Irganox 1010 (trade name), manufactured by BASF)) and N, N'-bis 3- (3'5'- Examples thereof include tert-butyl-4'-hydroxyphenyl) propionylhexamethylenediamine (Irganox 1098 (trade name), manufactured by BASF), and among them, Irganox 1010 is preferable. The phenolic anti-aging agent may be one kind or two or more kinds.

In the present invention, even if the anti-aging agent has a phenol structure and / or a benzimidazole structure in the molecule in addition to the hydrazine structure, it is a hydrazine-based heavy metal inactivating agent. Further, even if the anti-aging agent has a phenol structure in addition to the benzimidazole structure in the molecule, it is a benzimidazole-based anti-aging agent.

In the present invention, the catalyst composition for silane cross-linking may contain at least a benzimidazole-based anti-aging agent as an anti-aging agent, and is a benzimidazole-based anti-aging agent, a hydrazine-based heavy metal inactivating agent, and a phenol-based aging agent. It may contain one or both of the inhibitors. The combination of these anti-aging agents is appropriately determined, and for example, it suppresses aging (deterioration) of the crosslinked body due to contact with the conductor (metal) of the wiring material, and general aging other than aging due to contact with metal. From the viewpoint of suppression, it is preferable to use a benzimidazole-based antiaging agent and a hydrazine-based heavy metal inactivating agent in combination. On the other hand, from the viewpoint of imparting general aging resistance other than aging due to contact with the metal to the crosslinked product at a higher level, it is preferable to use a benzimidazole-based antiaging agent and a phenol-based antiaging agent in combination. .. Further, from the viewpoint of achieving both the above characteristics, it is preferable to use a benzimidazole-based antiaging agent, a hydrazine-based heavy metal inactivating agent, and a phenol-based antiaging agent in combination.

The content of the benzimidazole-based antiaging agent is 15 to 50 parts by mass, preferably 20 to 45 parts by mass, and more preferably 30 to 40 parts by mass with respect to 100 parts by mass of the carrier resin. Within this range, both suppression of foaming and excellent aging resistance can be achieved, and the appearance is also excellent.
The content of the hydrazine-based heavy metal inactivating agent is 0 to 25 parts by mass with respect to 100 parts by mass of the carrier resin. When this content is 25 parts by mass or less, foaming can be suppressed. From the viewpoint of suppressing foaming and suppressing deterioration due to contact with a metal, 5 to 20 parts by mass is preferable, and 10 to 15 parts by mass is more preferable.
The content of the phenolic antiaging agent is preferably 0 to 30 parts by mass, more preferably 5 to 20 parts by mass, and even more preferably 10 to 15 parts by mass with respect to 100 parts by mass of the carrier resin. Within this range, both suppression of foaming and excellent aging resistance can be achieved.
From the viewpoint of aging resistance, although it depends on the type of anti-aging agent to be combined, it is preferable that the total content of the anti-aging agent is as high as 25 to 100 parts by mass with respect to 100 parts by mass of the carrier resin. .. More preferably, it is 45 to 70 parts by mass.

<Additives>
The catalyst composition for silane cross-linking contains various additives generally used in electric wires, electric cables, electric cords, automobile parts, OA equipment, building parts, miscellaneous goods, sheets, foams, tubes, pipes, etc. , It may be appropriately contained within a range that does not impair the desired effect. Examples of such additives include cross-linking aids, lubricants, metal deactivators, flame-retardant (auxiliary) agents, and resins other than the above resin components.
The cross-linking aid refers to a compound that forms a partially cross-linked structure between resin components in the presence of an organic peroxide. For example, a polyfunctional compound and the like can be mentioned.
Examples of the lubricant include hydrocarbons, siloxanes, fatty acids, fatty acid amides, esters, alcohols, metal soaps and the like.

The melt flow rate of the catalyst composition for silane cross-linking is 0.1 to 15 g / 10 min. By setting the MFR to 0.1 to 15 g / 10 min, foaming can be suppressed during preparation of the catalyst composition for silane cross-linking. Further, a silane crosslinkable resin composition having excellent moldability when used in the silane crosslinking method can be obtained. The MFR is more preferably 0.5 to 10 g / 10 min, and even more preferably 1 to 3 g / 10 min, in that foam suppression and moldability can be compatible at a higher level.

The catalyst composition for silane cross-linking of the present invention uses a benzoimidazole-based antioxidant and a hydrazine-based heavy metal inactivating agent, and even if the content thereof is particularly increased, the catalyst composition for silane cross-linking is prepared. Foaming and further foaming during secondary processing of the wiring material obtained by using the catalyst composition for silane cross-linking can be suppressed, and the cross-linked body of the silane graft resin has excellent heat resistance and aging resistance. And the appearance can be given. The reason is not clear, but it can be considered as follows.
According to the findings of the present inventors, gas is generated when silanol condensation catalysts and anti-aging agents (particularly benzimidazole-based anti-aging agents and hydrazine-based heavy metal inactivating agents) or their decomposition products come into contact with each other at high temperatures. do. The generation of gas is particularly remarkable when the amount of the antiaging agent is high. However, in the present invention, the catalyst composition for silane cross-linking contains a polyolefin resin as a carrier resin, contains a specific amount of silanol condensation catalyst and an antioxidant, and the melt flow rate is within the above range and flows. Low sex. Even if these gas is generated in cooperation with each other, the resin component is less likely to expand due to this gas, and the gas is easily discharged to the outside of the silane cross-linking catalyst composition. Therefore, it is considered that the gas generated during the preparation of the catalyst composition for silane cross-linking is unlikely to remain and foaming is suppressed.
On the other hand, during the secondary processing of the silane crosslinked resin molded product, the silanol condensation catalyst usually disappears, and gas is not generated due to contact with the antiaging agent. However, it is considered that the silane crosslinked resin molded product contains gas or the like remaining in the silane crosslinked catalyst composition, or a low molecular weight component or the like. When a silane crosslinked resin molded product containing such a component is secondarily processed at a temperature higher than that at the time of preparation, these components (air bubbles) may become enormous and foam. However, even if the silane crosslinked resin molded product of the present invention is secondarily processed, foaming caused by the above components can be suppressed. Further, foaming can be suppressed even at a high temperature when preparing a silane crosslinkable resin composition using a silane crosslinking catalyst composition and a silane crosslinked resin molded product thereof.
Generally, when the fluidity is low, the moldability, particularly the high-speed moldability, deteriorates, and poor appearance and formation of lumps are observed. However, the silane cross-linking catalyst composition of the present invention is excellent in fluidity, and the gas generated as described above is unlikely to remain, and the silane cross-linking resin composition containing such a silane cross-linking catalyst composition can be molded. Foaming can be suppressed. Therefore, it is considered that molding at a relatively high temperature is possible, and a wiring material having an excellent appearance can be obtained.
Further, by using the silane cross-linking catalyst composition of the present invention, the silane cross-linking resin composition is silane-crosslinked to exhibit high heat resistance without impairing the foaming suppressing effect and appearance, and at a high content. Excellent anti-aging resistance can be imparted to the silane crosslinked resin molded product by the anti-aging agent contained therein.

<Manufacturing method of catalyst composition for silane cross-linking>
The catalyst composition for silane cross-linking is obtained by heating and mixing (kneading) a carrier resin, a benzimidazole-based antiaging agent, a silanol condensation catalyst, and various additives as needed. The heating temperature can be set to be equal to or higher than the melting temperature of the carrier resin, and is preferably set to, for example, 150 to 230 ° C. Other conditions, such as the mixing time, can be set as appropriate.
As the mixing method, a method usually used for rubber, plastic and the like can be adopted without particular limitation. As the mixing device, for example, a single-screw extruder, a twin-screw extruder, a roll, a Banbury mixer, various kneaders, or the like is used.

In the catalyst composition for silane cross-linking of the present invention, the method of setting the MFR to 0.1 to 15 g / 10 min is not particularly limited, and for example, the type, MFR or content of the polyolefin resin (each of the above resin components), and further. Can be mentioned as a method of changing the type or content of each anti-aging agent. Another method is to add a lubricant. In the present invention, the MFR is set as necessary.

[Silane crosslinkable resin composition]
Next, the silane crosslinkable resin composition of the present invention will be described.
The silane crosslinkable resin composition of the present invention is a melt mixture of a silane graft resin composition containing a base resin containing a silane graft resin as a resin component and the catalyst composition for silane crosslinking of the present invention. This silane crosslinkable resin composition is obtained by melt-mixing the silane graft resin composition and the silane crosslinkable catalyst composition of the present invention. In the silane crosslinkable resin composition, it is desirable that the hydrolyzable silyl group derived from the silane coupling agent has not undergone a condensation reaction, but a part of the hydrolyzable silyl group may be condensed at the time of melting or the like. Even in this case, the hydrolyzable silyl group is prepared by suppressing the condensation reaction to the extent that the silane crosslinkable resin composition has moldability in the molding step described later.
The silane crosslinkable resin composition of the present invention is excellent in moldability and can be molded at a relatively high speed. In addition, a silane crosslinked resin molded product having excellent heat resistance, aging resistance, and appearance can be obtained. The silane crosslinkable resin composition of the present invention can also be prepared by suppressing foaming at the time of preparation.

<Silane graft resin composition>
The silane graft resin composition (silane masterbatch: silane MB) is a composition containing a base resin containing a silane graft resin, and is composed of a base resin (a mode in which the base resin is used alone) and a base resin and required. It includes both aspects of a mode containing other components (a mode used as a composition) according to the above. The base resin contained in the silane graft resin composition includes a silane graft resin (a mode in which the silane graft resin is used alone) and a silane graft resin and, if necessary, other components (a mode in which the silane graft resin is used alone). Aspects used as a resin mixture) are included.
When the silane graft resin is synthesized by the step (a) described later, the silane graft resin composition and the base resin are a decomposition product of an organic peroxide, an unreacted silane coupling agent, and a condensation of the silane coupling agent. It may contain unreacted substances such as substances or by-products.

− Base resin −
The base resin contains a silane graft resin and, if necessary, other components. However, the base resin does not contain the inorganic filler described later.
(Silane graft resin)
The silane graft resin is formed by a silane coupling agent having a hydrolyzable silyl group undergoing a grafting reaction (bonding reaction between the crosslinkable group of the silane coupling agent and the crosslinked site of the resin component) with the resin. This silane graft resin is formed of a silane coupling agent and a resin, and has a component derived from the silane coupling agent as a graft chain (pendant).
In this silane graft resin, the amount of the grafting reaction of the silane coupling agent is not particularly limited. Usually, the amount of the grafting reaction obtained by reacting the silane coupling agent and the resin with the blending amount described later may be sufficient.

The resin forming the silane graft resin can undergo a grafting reaction in the presence of a site that can undergo a grafting reaction of a silane coupling agent (also referred to as a grafting reaction site) and a radical generated by decomposition of an organic peroxide, for example. It has an unsaturated bond site of a carbon chain, a polymer component having a carbon atom having a hydrogen atom in the main chain or at the end thereof. The polymer component is not particularly limited, but a polyolefin resin is preferable, and a resin component having a site capable of a grafting reaction may be contained in addition to the polyolefin resin.
The polyolefin resin is not particularly limited as long as it is a resin made of a polymer obtained by homopolymerizing or copolymerizing a compound having an ethylenically unsaturated bond, and is known as conventionally used in a resin composition. Can be used. For example, the polyolefin resin described in the carrier resin can be mentioned. Further, an acid-modified resin obtained by modifying this resin with an unsaturated carboxylic acid can also be mentioned.
The resin is preferably ethylene-vinyl acetate copolymer (EVA), ethylene- (meth) alkyl acrylate copolymer (for example, ethylene-ethyl acrylate copolymer resin), low-density polyethylene, or the like, and low-density polyethylene is preferable. Is more preferable.
As the resin forming the silane graft resin, one type may be used, or two or more types may be used.

As the silane coupling agent forming the silane graft resin, a grafting reaction site (group or atom) capable of performing a grafting reaction on the grafting reaction site of the resin and a hydrolyzable silyl group capable of silanol condensation are used. As long as it has, it is not particularly limited. The grafting reaction site (group or atom) is preferably one capable of performing a grafting reaction in the presence of radicals generated by decomposition of an organic peroxide, for example.
Examples of such a silane coupling agent include silane coupling agents conventionally used in the silane cross-linking method. Of these, those having a vinyl group and an alkoxysilyl group at the ends are preferable. Examples of such a silane coupling agent include vinyltrimethoxysilane, vinyltriethoxysilane, vinyltributoxysilane, vinyldimethoxyethoxysilane, vinyldimethoxybutoxysilane, vinyldiethoxybutoxysilane, allyltrimethoxysilane, and allyltriethoxy. Examples thereof include vinylsilanes such as silane and vinyltriacetoxysilane, and (meth) acryloxisilanes such as metharoxypropyltrimethoxysilane, metharoxypropyltriethoxysilane and metharoxypropylmethyldimethoxysilane. Of these, vinyltrimethoxysilane or vinyltriethoxysilane is particularly preferable.
As the silane coupling agent forming the silane graft resin, one type may be used, or two or more types may be used.

As the silane graft resin, a resin synthesized by a known method or a method described later may be used, or a commercially available product may be used. Examples of commercially available products include Linkron (trade name, manufactured by Mitsubishi Chemical Corporation).

When synthesizing a silane graft resin, it is preferable to use an organic peroxide. The organic peroxide generates radicals at least by thermal decomposition, and the grafting reaction by the radical reaction of the silane coupling agent to the resin (the grafting reaction site of the silane coupling agent and the grafting reaction site of the polyolefin resin). It is a covalent bond forming reaction with, and also has a function of causing a (radical) addition reaction). For example, when the silane coupling agent contains an ethylenically unsaturated group as a grafting reaction site, a grafting reaction is carried out by a radical reaction between the ethylenically unsaturated group and the polyolefin resin (including a reaction of extracting hydrogen radicals from the polyolefin resin). It works to cause it to occur. The organic peroxide is not particularly limited as long as it generates radicals, and is, for example, general formulas: R ^1- OO-R ² , R ^3- OO-C (= O) R ⁴ , R ⁵ C. The compound represented by (= O) -OO (C = O) R ^{6 is preferable.} Here, R ^{1 to} R ⁶ independently represent an alkyl group, an aryl group, or an acyl group, respectively. ^{Of R 1 to} R ⁶ of each compound, those which are all alkyl groups or those in which one is an alkyl group and the rest are acyl groups are preferable.

Examples of such organic peroxides include dicumyl peroxide (DCP), di-tert-butyl peroxide, 2,5-dimethyl-2,5-di- (tert-butylperoxy) hexane, and 2 , 5-Dimethyl-2,5-di (tert-butylperoxy) hexin-3, 1,3-bis (tert-butylperoxyisopropyl) benzene, 1,1-bis (tert-butylperoxy) -3 , 3,5-trimethylcyclohexane, n-butyl-4,4-bis (tert-butylperoxy) ballerate, benzoyl peroxide, p-chlorobenzoyl peroxide, 2,4-dichlorobenzoyl peroxide, tert-butylper Examples thereof include oxybenzoate, tert-butyl peroxyisopropyl carbonate, diacetyl peroxide, lauroyl peroxide, tert-butyl cumyl peroxide and the like. Of these, dicumyl peroxide, 2,5-dimethyl-2,5-di- (tert-butylperoxy) hexane, and 2,5-dimethyl-2 in terms of odor, colorability, and scorch stability. , 5-Di (tert-butylperoxy) hexin-3 is preferred.

The decomposition temperature of the organic peroxide is preferably 80 to 195 ° C, particularly preferably 125 to 180 ° C.
In the present invention, the decomposition temperature of an organic peroxide is the temperature at which a single composition of an organic peroxide causes a decomposition reaction with two or more compounds in a certain temperature or temperature range. means. Specifically, it refers to the temperature at which heat absorption or heat generation starts when heated from room temperature at a heating rate of 5 ° C./min in a nitrogen gas atmosphere by thermal analysis such as the DSC method.

The silane graft resin is obtained by reacting the resin with a silane coupling agent at a temperature equal to or higher than the decomposition temperature of the organic peroxide. Specific reaction conditions include the melt-mixing conditions of step (a) described later.

(Other components that the base resin may contain)
The other components that may be contained in the base resin are not particularly limited, and examples thereof include resins other than the silane graft resin, mineral oil, and the like. Examples of the resin and the mineral oil other than the silane graft resin include the polyolefin resin and the mineral oil described in the carrier resin.
The content of the silane graft resin in 100% by mass of the base resin is preferably 50 to 100% by mass.
The base resin preferably contains a styrene-based elastomer as a resin other than the silane graft resin. The content of the styrene-based elastomer in the base resin is preferably 10% by mass or more, and more preferably 10 to 40% by mass.
The base resin, particularly the base resin containing a styrene-based elastomer, may contain the above-mentioned mineral oil. The content of the mineral oil in the base resin is preferably 0 to 30% by mass.

When the base resin is used as the resin mixture, the base resin can be prepared by mixing the silane graft resin and other components by a usual mixing method.

− Other components that may be contained in the silane graft resin composition −
The other components that may be contained in the silane graft resin composition are not particularly limited as long as they are components other than the other components that may be contained in the base resin, and the inorganic filler and the catalyst composition for silane cross-linking are used. Examples thereof include the above-mentioned various additives that may be contained.

(Inorganic filler)
The inorganic filler that may be contained in the silane graft resin composition is not particularly limited as long as it is usually used, but on its surface, a hydrolyzable silyl group of a silane coupling agent and a hydrogen bond, a covalent bond, etc., or the like, or Those having a site or the like that can be chemically bonded by an intermolecular bond are preferable. Examples of the site capable of chemically bonding with the hydrolyzable silyl group include an OH group (hydroxyl group, water molecule of water-containing or crystalline water, OH group such as carboxy group), amino group, SH group and the like.
When such an inorganic filler is used particularly in the step (a) described later, a silane graft resin in which a silane coupling agent weakly bonded to the inorganic filler has undergone a grafting reaction and a silane coupling agent strongly bonded to the inorganic filler are grafted. It is possible to form a silane graft resin that has undergone a chemical reaction. By cross-linking these two types of silane graft resins, it is possible to form a silane cross-linked resin molded product having both heat resistance and strength.
Here, examples of weak bonds with the inorganic filler include interactions due to hydrogen bonds, interactions between ions, partial charges or dipoles, and actions due to adsorption. Further, examples of the strong bond with the inorganic filler include a chemical bond with a portion of the surface of the inorganic filler that can be chemically bonded.

The above-mentioned inorganic filler is not particularly limited, and for example, aluminum hydroxide, magnesium hydroxide, calcium carbonate, magnesium carbonate, calcium silicate, magnesium silicate, calcium oxide, magnesium oxide, aluminum oxide, aluminum nitride, aluminum borate. Examples thereof include metal hydrates such as whisker, hydrated aluminum silicate, hydrated magnesium silicate, basic magnesium carbonate, hydrotalcite, talc and other compounds having hydroxyl groups or crystalline water. In addition, boron nitride, silica (crystalline silica, amorphous silica, etc.), carbon, clay, zinc oxide, tin oxide, titanium oxide, molybdenum oxide, antimony trioxide, silicone compound, quartz, zinc borate, white carbon, Zinc borate, zinc hydroxytinate, zinc stannate and the like can also be mentioned. Of these, aluminum hydroxide or magnesium hydroxide is preferable.
As the inorganic filler, those surface-treated with various surface treatment agents can also be used.
One type of inorganic filler may be used alone, or two or more types may be used in combination.
The content of the inorganic filler in the silane graft resin composition is not particularly limited and can be appropriately set. Preferably, the blending amount is set so as to be the blending amount in the step (a2) described later with respect to 100 parts by mass of the total of the carrier resin and the base resin.

The silane graft resin composition can be prepared by mixing the base resin and the above-mentioned other components by a usual mixing method, or can be prepared as in the step (a) described later. In the present invention, it is preferable to prepare as in the step (a) described later.
When the base resin contains the above other components, a resin mixture prepared in advance may be used as the base resin, or the silane graft resin and the other components may be used separately.

[Silane cross-linked resin molded article preparation kit]
The catalyst composition for silane cross-linking of the present invention can also be used as a kit for preparing a silane cross-linked resin molded product in combination with the silane graft resin composition.
In the kit for preparing a silane crosslinked resin molded product, the silane graft resin may be used alone as the silane graft resin composition in combination with the silane crosslinked catalyst composition.
This kit for preparing a silane crosslinked resin molded product may be used in any production method as long as it can produce a silane crosslinked resin molded product. Preferably, it is used in a method for producing a silane crosslinked resin molded product, which will be described later, particularly in step (b) of this production method.
In the silane cross-linked resin molded article preparation kit, the mixing ratio of the silane graft resin composition and the silane cross-linking catalyst composition is not particularly limited, but at least when used, it should be used in the mixing ratio described in step (b) described later. Is preferable.

[Manufacturing Method of Silane Crosslinkable Resin Composition, Silane Crosslinkable Resin Mold, and Wiring Material]
Next, a method for producing a silane crosslinkable resin composition, a silane crosslinked resin molded product, and a wiring material using the silane crosslinking catalyst composition of the present invention will be described.

The method for producing a silane crosslinkable resin composition includes, for example, a step of melt-mixing the silane graft resin composition and the silane crosslinkable catalyst composition of the present invention. The melt-mixing can be applied to the usual methods (conditions) and the apparatus without particular limitation. For example, the method (conditions) and the apparatus described in the melt-mixing in the step (b) of the following method for producing a silane crosslinked resin molded product. Can be applied.
The method for producing the silane-crosslinked resin molded product is not particularly limited as long as it is a silane-crosslinked method using the silane-crosslinked catalyst composition of the present invention, and a normal silane-crosslinked method can be applied. For example, a silane cross-linking method having the following steps (b) and (c) can be mentioned.
Step (b): A step of melt-mixing the silane graft resin composition and the silane cross-linking catalyst composition of the present invention and then molding. Step (c): A molded product (of the melt mixture) obtained in the step (b). Step of cross-linking by contact with water The method for producing the wiring material may be any method as long as the coating layer can be formed of a cured product of the silane cross-linking resin composition. For example, a method for producing a silane-crosslinked resin molded product was used. The method can be mentioned.

Hereinafter, the above steps (b) and (c) in the method for producing a silane crosslinked resin molded product will be described step by step.
The method for melt-mixing the silane graft resin composition and the catalyst composition for silane cross-linking of the present invention in the step (b) is not particularly limited as long as it is a method usually used for rubber, plastic and the like. The mixing device is appropriately selected depending on, for example, the blending amount of the inorganic filler. As the mixing device, a single-screw extruder, a twin-screw extruder, a roll, a Banbury mixer, various kneaders, or the like is used. In terms of dispersibility of the resin component, it is preferable to use a Banbury mixer or a closed mixer such as various kneaders. The melting temperature is appropriately selected according to the melting temperature of the base resin or the carrier resin, and is, for example, preferably 80 to 250 ° C., more preferably 100 to 240 ° C. Other conditions, such as the mixing time, can be set as appropriate. Step (b) is carried out while suppressing the silanol condensation reaction of the coupling agent grafted on the resin. For example, it is preferable to carry out the operation under a condition where the abundance of water is small, and it is preferable that the silane graft resin composition and the silanol condensation catalyst are not kept in a high temperature state for a long time in a mixed state.

The silane graft resin composition and the catalyst composition for silane cross-linking of the present invention can be dry-blended before being melt-mixed. The method and conditions for dry blending are not particularly limited, and examples thereof include dry mixing in the step (a2-1) described later and the conditions thereof.

The mixing ratio of the silane graft resin composition and the catalyst composition for silane cross-linking of the present invention is preferably set from the viewpoint of the mixing ratio of the silanol condensation catalyst or the carrier resin.

The mixing ratio of the silanol condensation catalyst is 0.02 to 0.5 with respect to 100 parts by mass of the total of the base resin in the silane graft resin composition and the carrier resin in the silane cross-linking catalyst composition of the present invention. It is preferably set to the mass part. That is, the silane cross-linking catalyst composition of the present invention and the silane graft resin composition may be mixed at a ratio of 0.02 to 0.5 parts by mass of the silanol condensation catalyst with respect to the total of 100 parts by mass. preferable. When the mixing ratio of the silanol condensation catalyst is within this range, poor appearance and generation of lumps can be effectively suppressed, and the cross-linking reaction in the step (c) described later can be sufficiently advanced. Therefore, the obtained silane crosslinked resin composition can be made excellent in moldability, and high heat resistance can be imparted to the obtained silane crosslinked resin molded product. The mixing ratio of the silanol condensation catalyst is preferably 0.05 to 0.4 parts by mass, and more preferably 0.08 to 0.3 parts by mass with respect to the total of 100 parts by mass.
Here, when the silane graft resin composition is synthesized and used in the step (a) described later, the amount (part by mass) of the base resin is the resin used for synthesizing the silane graft resin (resin forming the silane graft resin). ), The silane coupling agent, the resin other than the silane graft resin, and the mineral oil.

The mixing ratio of the carrier resin is preferably set to 2 to 60% by mass based on 100% by mass of the total of the base resin and the carrier resin. That is, it is preferable that the carrier resin is mixed with the silane graft resin composition in a proportion of 2 to 60% by mass in the total of 100% by mass. When the mixing ratio of the carrier resin is within this range, the generation of lumps can be effectively suppressed, and the cross-linking reaction can be sufficiently advanced in the steps described later. The mixing ratio of the carrier resin is more preferably set to 15 to 40% by mass, and further preferably set to 18 to 35% by mass.

In this way, a melt mixture (silane crosslinkable resin composition) can be obtained. The content of each component in this molten mixture is the content of the corresponding component in the silane graft resin composition and the silane cross-linking catalyst composition of the present invention, and the silane graft resin composition and the silane cross-linking catalyst composition of the present invention. It is determined from the mixing ratio at the time of melt mixing.
For example, in a silane crosslinkable resin composition using a silane graft resin composition in which the base resin contains 10% by mass or more of a styrene-based elastomer, the content of the styrene-based elastomer is 100% by mass in total of the base resin and the carrier resin. On the other hand, it is preferably 5% by mass or more.
Further, for example, in the silane crosslinkable resin composition, the content of the silane graft resin is preferably 50 to 100% by mass, preferably 60 to 90% by mass, based on 100% by mass of the total of the base resin and the carrier resin. Is more preferable.

In step (b), the obtained molten mixture is molded.
In this molding step, it is sufficient that the melt mixture can be molded, and an appropriate molding method and molding conditions are selected according to the form of the silane crosslinked resin molded body. Examples of the molding method include extrusion molding using an extruder, extrusion molding using an injection molding machine, and molding using another molding machine.
Extrusion molding is preferably applied when the product containing the silane crosslinked resin molded product is a wiring material, particularly an electric wire or an optical fiber cable. Extrusion molding can be performed using a general-purpose extrusion molding machine. The extrusion molding temperature depends on the type of base resin or carrier resin and various conditions of extrusion speed (take-up speed), but the cylinder part is 120 to 150 ° C and the crosshead part (die temperature) is about 160 to 200 ° C. It is preferable to set to.
When the molding of the step (b) is performed by extrusion molding, the molding speed (extrusion speed) of the molten mixture is not particularly limited, and usually, the linear speed is 1 mm / min or more and less than 20 mm / min, preferably 1 mm / min or more. It can be set to 10 mm / min or less. Further, in the present invention, the molding speed can be set to a high linear speed of 20 mm / min or more and 200 mm / min or less in order to further improve the productivity.

In the step (b), the molding step can be performed simultaneously with or continuously of the above-mentioned melting and mixing step. That is, as one embodiment of melt mixing in the melt mixing step, for example, there is an embodiment in which a molding material (silane graft resin composition and the catalyst composition for silane cross-linking of the present invention) is melt-mixed at the time of extrusion molding or immediately before. For example, the molding material may be mixed at room temperature or high temperature (in a state where it does not melt) and introduced into a molding machine to be melt-mixed. Alternatively, the molding material may be melt-mixed and pelletized, and then introduced into a molding machine and melt-mixed again. In this case, more specifically, a mixture of the silane graft resin composition and the catalyst composition for silane cross-linking of the present invention is melt-mixed in a coating device, and then extruded and coated on the outer peripheral surface of a conductor or the like, which is desired. A series of steps of molding into the shape of can be adopted. In this way, the silane graft resin composition and the catalyst composition for silane cross-linking of the present invention are dry-blended to prepare a dry blend, and when this dry blend is introduced into a molding machine for molding, the silane cross-linking property is obtained. A crosslinkable resin molded product can be obtained as a molded product of the resin composition.

The crosslinkable resin molded product obtained in step (b) is an uncrosslinked product in which the hydrolyzable silyl group derived from the silane coupling agent is not silanol-condensed. In practice, when melt-mixed in step (b), partial cross-linking (partial cross-linking) is unavoidable, but at least the formability at the time of molding is maintained for the obtained cross-linkable resin molded product. It is preferable to do so. It is also preferable that the appearance is not deteriorated.
When the silane graft resin composition is synthesized and used in the step (a) described later, in the crosslinkable resin molded product, some hydrolyzable silyl groups may be bonded or adsorbed to the inorganic filler. In this case, the crosslinkable resin molded body is a silane graft resin grafted with a silane coupling agent bonded or adsorbed with an inorganic filler by a hydrolyzable silyl group, and the hydrolyzable silyl group is not bonded or adsorbed with the inorganic filler. Contains a silane graft resin grafted with a silane coupling agent.

In the step (c), the crosslinkable resin molded product obtained in the step (b) is brought into contact with water. This crosslinkable resin molded product is made into a (final) crosslinked silane crosslinked resin molded product by carrying out the step (c). That is, the hydrolyzable silyl group of the silane graft resin is hydrolyzed to silanol (OH group bonded to the silicon atom), and the hydroxyl groups of silanol are (dehydrated) by the silanol condensation catalyst present in the crosslinkable resin molded body. Condensation occurs and a cross-linking reaction occurs.
The process itself of this step (c) can be performed by a usual method. The condensation reaction proceeds only by storing at room temperature in the presence of a silanol condensation catalyst. Therefore, in step (c), it is not necessary to positively contact the crosslinkable resin molded product with water. In order to promote this condensation reaction, the crosslinkable resin molded product can also be brought into contact with water. For example, a method of actively contacting with water such as immersion in hot water, charging into a moist heat tank, and exposure to high-temperature steam can be adopted. Further, at that time, pressure may be applied to allow water to permeate into the inside.
In this way, a silane crosslinked resin molded product is produced.

The silane graft resin composition used in the step (b) may be a commercially available product or a prepared product (synthetic product). The method for preparing the silane graft resin composition is not particularly limited, and examples thereof include a method using a commercially available silane graft resin and a method including a step of synthesizing the silane graft resin.
Examples of the method using a commercially available silane graft resin include a method of mixing the silane graft resin with a base resin component other than the silane graft resin, an inorganic filler, and the like. The mixing method and mixing conditions are not particularly limited and can be set as appropriate.

Examples of the method including the silane graft resin synthesis step (a) include a method including a step (a1) of synthesizing a silane graft resin without using an inorganic filler, and a method of synthesizing a silane graft resin in the presence of an inorganic filler. A method including the step (a2) is preferably mentioned. In the present invention, step (a1) is preferable. The step (a2) is preferable from the viewpoint of promoting cross-linking and increasing heat resistance.

That is, a preferred embodiment of the method for producing a silane crosslinked resin molded product includes the following steps (a1), the above steps (b) and (c). The silane graft resin composition obtained in the step (a1) is used in the above step (b).
Step (a1): A resin that forms a silane graft resin to be contained in the base resin when the total amount of the base resin and the carrier resin to be mixed in the step (b) is 100 parts by mass (hereinafter, for forming a silane graft resin). Resin is referred to as resin), 0.003 to 0.3 parts by mass of organic peroxide, and more than 2 parts by mass of the silane coupling agent having a grafting reaction site and 15.0 parts by mass or less of the organic peroxide. Silane containing a base resin containing a silane graft resin by melt-mixing at a temperature equal to or higher than the decomposition temperature and grafting a silane coupling agent with a resin for forming a silane graft resin by radicals generated from an organic peroxide. Step of Obtaining Graft Resin Composition Further, another preferable aspect of the method for producing a silane crosslinked resin molded product includes the following step (a2) instead of the above step (a1). The silane graft resin composition containing the inorganic filler obtained in the step (a2) is used in the above step (b).
Step (a2): When the total amount of the base resin and the carrier resin to be mixed in step (b) is 100 parts by mass, the resin for forming the silane graft resin and 0.003 to 0.3 parts by mass of the organic peroxide are used. , 10 to 400 parts by mass of the inorganic filler and more than 2 parts by mass of the silane coupling agent having a grafting reaction site and 15.0 parts by mass or less are melt-mixed at a temperature equal to or higher than the decomposition temperature of the organic peroxide. , A step of obtaining a silane graft resin composition containing a base resin containing a silane graft resin by subjecting a silane coupling agent to a resin for forming a silane graft resin with radicals generated from an organic peroxide. In (a1) and (a2), if necessary, a resin other than the above-mentioned silane graft resin, a mineral oil, and an additive may be mixed. The blending amount of the resin other than the silane graft resin and the mineral oil is determined in consideration of the blending amount of the resin for forming the silane graft resin. The blending amount of the additive is appropriately set as long as the object of the present invention is not impaired.

The above steps (a1) and (a2) will be collectively referred to as a step (a).

In the step (a), the blending amount of the organic peroxide is preferably 0.003 to 0.3 parts by mass, preferably 0.005 to 0.3 parts by mass, based on 100 parts by mass of the total of the base resin and the carrier resin. Parts are more preferable, and 0.005 to 0.1 parts by mass is further preferable. By setting the blending amount of the organic peroxide within the above range, the grafting reaction can be carried out in an appropriate range, the generation of lumps can be suppressed, and a silane graft resin composition having excellent extrudability can be prepared. can.

In the step (a2), the blending amount of the inorganic filler is preferably 10 to 400 parts by mass, more preferably 30 to 280 parts by mass, based on the total 100 parts by mass. By setting the blending amount of the inorganic filler within the above range, high heat resistance and excellent appearance can be imparted to the silane crosslinked resin molded product.

In the step (a), the blending amount of the silane coupling agent is preferably more than 2.0 parts by mass and 15.0 parts by mass or less, more preferably 3 to 12.0 parts by mass, out of the total 100 parts by mass. ~ 12.0 parts by mass is more preferable. By setting the blending amount of the silane coupling agent within the above range, high heat resistance and excellent appearance can be imparted to the silane crosslinked resin molded product.

In the present invention, "a resin for forming a silane graft resin, an organic peroxide, and a silane coupling agent are melt-mixed" (step (a1)), "a resin for forming a silane graft resin, an organic peroxide, and the like. , Inorganic filler and silane coupling agent are melt-mixed ”(step (a2)), which does not specify the mixing order at the time of melt-mixing, and may be mixed in any order. It means good.
In the step (a2), it is preferable that each of the above components is melt-mixed by the following steps (a2-1) and (a2-2).
Step (a2-1): Mixing at least an inorganic filler and a silane coupling agent having a grafting reaction site to prepare a mixture Step (a2-2): Mixing and silane obtained in step (a2-1) The graft resin forming resin is melt-mixed in the presence of the organic peroxide at a temperature equal to or higher than the decomposition temperature of the organic peroxide, and the radical generated from the organic peroxide is used to form the silane graft resin forming resin. A step of obtaining a silane graft resin composition containing a base resin containing a silane graft resin by subjecting a silane coupling agent to a grafting reaction.

In the step (a2-1), the method of mixing the inorganic filler and the silane coupling agent is not particularly limited, and may be wet mixing or dry mixing. In the present invention, a dry mixture (dry blend) in which a silane coupling agent is mixed with an inorganic filler with or without heating is preferable. The silane coupling agent premixed in this manner exists so as to surround the surface of the inorganic filler, and a part or all of the silane coupling agent is adsorbed or bonded to the inorganic filler. This makes it possible to reduce the volatilization of the silane coupling agent during the subsequent melt mixing. The dry mixing is carried out at a temperature lower than the decomposition temperature of the organic peroxide, and the above components are mixed while suppressing the occurrence of the grafting reaction. The mixing temperature is preferably 10 to 50 ° C., more preferably room temperature (25 ° C.) to 40 ° C., and the conditions of the inorganic filler and the silane coupling agent can be set to about several minutes to several hours.
The organic peroxide may be present when the step (a2-2) is performed, and may be mixed in the step (a2-1) or may be mixed in the step (a2-2).

Next, the mixture obtained in step (a2-1) and the resin for forming a silane graft resin are melt-mixed (step (a2-2)). As a result, the radical generated from the organic peroxide causes the grafting reaction site of the silane coupling agent and the grafting reaction site of the resin for forming the silane graft resin to undergo a grafting (bonding) reaction.

In each of the melt mixing of the step (a1), the step (a2) and the step (a2-2), the temperature at which the above components are melt-mixed is equal to or higher than the decomposition temperature of the organic peroxide, preferably 150 to 230 ° C. .. Other mixing conditions, for example, the mixing time can be set as appropriate. As a result, the organic peroxide is decomposed and the generated radicals act on the melted components, so that the grafting reaction site of the silane coupling agent and the grafting reaction site of the silane graft resin forming resin are formed. The grafting reaction (binding) proceeds. The melt-mixing method is not particularly limited, and the mixture can be mixed in the same manner as in the above-mentioned step (b).

In the step (a), the resin other than the silane graft resin, the mineral oil and the additive may be mixed in any of the above steps.

In this way, the step (a) can be performed to prepare a silane graft resin composition containing a silane graft resin.
The step (a) can be performed simultaneously or continuously with the melting and mixing of the above step (b).

It is preferable that the step (a) is performed in the absence of a silanol condensation catalyst to suppress the condensation reaction of the silane coupling agent. In the present invention, melt-kneading in the absence of a silanol condensation catalyst means melt-kneading without substantially blending the silanol condensation catalyst. That is, it does not exclude the silanol condensation catalyst that is inevitably present, and means that it may be present as long as the following problems of kneadability and moldability due to silanol condensation of the silane coupling agent do not occur. do. For example, the silanol condensation catalyst may be present as long as it is 0.01 parts by mass or less with respect to 100 parts by mass of the resin composition. By performing the above melt-kneading in the absence of a silanol condensation catalyst, the condensation reaction of the silane coupling agent can be suppressed, the kneadability is excellent (easy to melt-knead), and the moldability is excellent (desired shape). Can be extruded into).
In this way, the silane graft resin is synthesized by grafting the silane graft resin forming resin with the silane coupling agent, and a silane graft resin composition containing the silane graft resin is prepared as the reaction composition. NS. In this grafting reaction, one molecule of silane coupling agent is usually added to one grafting reaction-capable site, but the present invention is not limited thereto. This silane graft resin composition is a reaction composition containing a silane graft resin in which a silane coupling agent is grafted to a base resin to the extent that it can be molded by the above-mentioned step (b).

In the step (a2-2), at least the following modes can be mentioned as an embodiment in which the silane coupling agent undergoes a grafting reaction with the resin for forming a silane graft resin. The silane coupling agent bonded or adsorbed to the inorganic filler with a weak bond in the above step (a2-1) is desorbed from the inorganic filler and undergoes a grafting reaction with the resin for forming a silane graft resin in the step (a2-2). Further, the silane coupling agent bonded or adsorbed to the inorganic filler with a strong bond reacts with the resin for forming the silane graft resin while maintaining the bond with the inorganic filler.

As described above, the silane crosslinked resin molded product is produced. This silane crosslinked resin molded product contains a crosslinked resin obtained by cross-linking the above-mentioned silane graft resin.
In one form of the silane crosslinked resin molded product produced through the above step (a1), the silane coupling agents grafted to the resin for forming the silane graft resin are crosslinked with each other (silanol condensation reaction between hydrolyzable silyl groups). By doing so, it contains a crosslinked body of the silane graft resin bonded (crosslinked) via at least two silane coupling agents.
It is considered that one form of the silane crosslinked resin molded product produced through the above step (a2) contains the following crosslinked silane graft resin. The silane coupling agent desorbed from the inorganic filler and grafted onto the resin for forming the silane graft resin undergoes a cross-linking reaction to contain a crosslinked body of the silane graft resin bonded (crosslinked) via the silane coupling agent. In addition to this, the silane coupling agent that has undergone a graft reaction with the resin for forming a silane graft resin while maintaining the bond with the inorganic filler is unlikely to undergo a cross-linking reaction, and is bonded (cross-linked) with the inorganic filler via the silane coupling agent. Contains a crosslinked body of the silane graft resin. The silane crosslinked resin molded product containing the crosslinked product of these resins exhibits excellent appearance and high heat resistance without impairing high aging resistance, and further has high strength.

<Application of manufacturing method for silane crosslinked resin molded product>
The method for producing a silane crosslinked resin molded product can be applied to the production of a product (including semi-finished products, parts, and members) made of a silane crosslinked resin molded product. This product may be a product containing a silane crosslinked resin molded product, or may be a product composed of only a silane crosslinked resin molded product. Examples of such products include coating materials for wiring materials such as heat-resistant electric wires, cables or optical fiber cables, rubber mold materials (for example, automobile glass run channels, weather strips, rubber hoses, wiper blade rubber, anti-vibration rubber) and the like. Be done. Further, the silane crosslinked resin molded product can be conventionally used as a substitute for a polyolefin material or EP rubber material crosslinked or chemically vulcanized by electron beam irradiation.
A product containing a silane cross-linked resin molded product can be produced by using a silane cross-linking catalyst composition and a silane graft resin composition and molding the product together with other members by a usual method.

[Wiring material]
The wiring material of the present invention has a coating layer made of a cured product of a silane crosslinkable resin composition. In other words, the wiring material of the present invention is a product containing a silane crosslinked resin molded product, and has a coating layer made of the silane crosslinked resin molded product. This coating layer is formed by using the catalyst composition for silane cross-linking of the present invention, contains a cross-linked product of a silane graft resin as a base (matrix) thereof, and further contains an antioxidant in a high content. Therefore, the wiring material provided with this coating layer is excellent in heat resistance, aging resistance, and appearance, and is less likely to foam during secondary processing.
Examples of the wiring material include heat-resistant electric wires, cables, cords, optical fiber core wires or optical fiber cords used for internal wiring or external wiring of electrical / electronic equipment, and heat-resistant electric wires or cables are preferable.
The wiring material of the present invention is a wiring material that requires a particularly high degree of aging resistance (for example, a wiring material used around a car engine, a wiring material for an air conditioner, a wiring material for a range, etc., in a high temperature environment. It can be preferably used as a wiring material that is used for a long period of time.

The wiring material of the present invention can be produced by a known method, and is preferably produced by a method for producing a silane crosslinked resin molded product.
When the wiring material of the present invention is produced by extrusion molding using the silane cross-linking catalyst composition of the present invention in the method for producing a silane cross-linked resin molded body, the silane cross-linking catalyst composition of the present invention and the silane graft are preferably produced. A coating layer made of a silane crosslinked resin molded body was provided by melting and mixing a molding material mixed with a resin composition in an extruder (extrusion coating device), extruding it to the outer periphery of a conductor or the like, and then bringing it into contact with water. Can manufacture wiring materials.
The conductor to be used may be a single wire or a stranded wire, or may be a bare wire or a tin-plated or enamel-coated conductor. Examples of the metal material forming the conductor include annealed copper, copper alloy, aluminum and the like. The wall thickness of the insulating layer formed around the conductor is not particularly limited, but is usually about 0.15 to 5 mm.

Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited thereto.
In Tables 1 to 3, the numerical values relating to the blending amounts of each example represent parts by mass unless otherwise specified. Further, the blanks for each component mean that the blending amount of the corresponding component is 0 parts by mass.

Details of each component (compound) shown in Tables 1 to 3 are shown below.
Hindered phenolic anti-aging agent: Irganox 1010 (trade name, pentaerythritol tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], manufactured by BASF)
Hydrazine-based heavy metal inactivating agent: Irganox MD1024 (trade name, 1,2-bis [3- (4-hydroxy-3,5-di-tert-butylphenyl) propionyl] hydrazine, manufactured by BASF)
Benzimidazole anti-aging agent: Nocrack MBZ (trade name, 1,3-dihydro-2H-benzimidazol-2-thione 0.5 zinc salt, manufactured by Ouchi Shinko Kagaku Kogyo Co., Ltd.)

Silanol condensation catalyst: ADEKA STAB OT-1 (trade name, dioctyltin dilaurate, manufactured by ADEKA)

HDPE: Hi-Zex 5305E (trade name, high-density polyethylene, MFR 0.8g / 10 minutes, manufactured by Prime Polymer Co., Ltd.)
LLDPE: Evolu SP0540 (trade name, linear low density polyethylene, MFR 3.8 g / 10 minutes, manufactured by Prime Polymer Co., Ltd.)
PP: PB222A (trade name, polypropylene, MFR 0.7 g / 10 minutes (230 ° C, 2.16 kg), manufactured by SunAllomer Ltd.)
EVA: EVAFlex EV360 (trade name, ethylene-vinyl acetate copolymer, MFR 2g / 10 minutes, manufactured by Mitsui / DuPont Polychemical)
EEA: NUC6510 (trade name, ethylene-ethyl acrylate copolymer resin, MFR 0.5 g / 10 minutes, manufactured by NUC)
EPDM: Nodel 3720P (trade name, ethylene-α-olefin copolymer rubber, MFR 0.7 g / 10 minutes, manufactured by Dow Inc.)
Ethylene acrylic rubber: Baymac DP (trade name, MFR 0.7g / 10 minutes or less, manufactured by DuPont)
SEPS: Septon 4077 (trade name, manufactured by Kuraray)
OIL: Diana Process PW90 (trade name, paraffin oil, dynamic viscosity at 40 ° C, 96 cSt, pour point 15 ° C, flash point (COC) 250 ° C or higher, manufactured by Idemitsu Kosan Co., Ltd.)
Silane Graft LLDPE: Linkron XCF730M (trade name, manufactured by Mitsubishi Chemical Corporation)

(Examples 1 to 10, 12, 15, 17 to 20, Comparative Examples 1 to 8, Reference Examples 1 to 4 )
First, each component shown in the "catalyst masterbatch" column of Tables 1 to 3 was melt-mixed at 200 ° C. using a Banbury mixer and then pelletized to obtain pellets of the catalyst masterbatch. The catalyst masterbatch contained the benzimidazole-based antiaging agent, the hydrazine-based heavy metal inactivating agent, and the hindered phenol-based antiaging agent in the amounts shown in Tables 1 to 3.
Further, in Examples 19 and 20, each component shown in the “Silane masterbatch” column was melt-mixed at 200 ° C. using a Banbury mixer and then pelletized to obtain pellets of the silane masterbatch.

Further, each component shown in the "silane masterbatch" column of Tables 1 to 3 or the silane masterbatch prepared above and the catalyst masterbatch prepared above were dry-blended to obtain a dry blend. The mixing ratio at this time is the mixing ratio shown in the “Silane masterbatch” column for the silane graft resin, and the mass shown in the “Catalyst masterbatch mixed with the silane masterbatch” column in Tables 1 to 3 for the catalyst masterbatch. The ratio (the total of the base resin and the carrier resin is 100 parts by mass).
Each mixing ratio shown in the “Catalyst masterbatch mixed with silane masterbatch” column in Tables 1 to 3 corresponds to the mixing ratio with respect to 100 parts by mass of the total amount of the base resin and the carrier resin.

Next, a 25 mmφ extruder (ratio of effective screw length L to diameter D: L / D = 25) is placed at a die temperature of 160 ° C., hereinafter to the feeder side, C3 = 150 ° C., C2 = 140 ° C., C1 = 130 ° C. It was set to the extrusion temperature condition of. The prepared dry blend is put into this extruder and melt-mixed to prepare a melt mixture (silane crosslinkable resin composition), and the melt mixture is placed on a 0.8 mmφ conductor made of bare annealed copper wire with an outer diameter. Extrusion coating was performed so as to have a thickness of 1.2 mmφ and a thickness of 0.2 mm.
The obtained coated conductor (crosslinkable resin molded product) was left to stand in an environment of 23 ° C. and a relative humidity of 50% for 24 hours to be brought into contact with water. In this way, an electric wire having a coating layer made of a cured product of the silane crosslinkable resin composition was produced.

The following tests were performed on each pellet obtained in the same manner as the extrusion coating, each coated conductor obtained above, or each electric wire manufactured, and the results are shown in Tables 1 to 3.

[Effervescence test 1 (evaluation of effervescence suppression during catalyst MB preparation)]
The central portion of 10 grains randomly selected from the pellets of the catalyst masterbatch obtained above was cut (cut at the center of the major axis so as to be orthogonal to the major axis), and the cut surface was visually observed. As a result, those in which no foaming was observed on the cut surfaces of all the pellets (passed) were marked with "○", and those in which even one foam was observed (failed) were marked with "x".
Here, the term "no foaming" means that no bubbles (voids) having a size of 0.05 mm or more are observed on the cut surface.

[Effervescence test 2 (evaluation of foam suppression during secondary processing)]
As a foaming test of the electric wire, a solder heat resistance test was performed assuming the presence or absence of foaming during the secondary processing. Specifically, the coating layer of the electric wire was peeled off by 5 mm from the tip, and the portion having a length of 3 mm from the tip of the conductor exposed after the coating layer was peeled off was immersed in a solder bath set at 330 ° C. and held. Then, the electric wire was pulled up from the solder bath, and the presence or absence of foaming in the cross section of the coating layer of the electric wire, which was 5 mm in length from the tip of the exposed conductor and was perpendicular to the length direction of the conductor, was confirmed. Observation of foaming was performed using a microscope. Here, the term "no foaming" means that no bubbles (voids) having a size of 0.01 mm or more are observed in the cross section.
In the above immersion, the presence or absence of foaming was evaluated according to the following evaluation criteria based on the maximum immersion time in which no foaming was observed in the cross section of the coating layer.
When the maximum immersion time is 10 seconds or more, it is indicated by "◎", when it is 5 seconds or more and less than 10 seconds, it is indicated by "○", and when it is 1 second or more and less than 5 seconds, " It is indicated by "Δ", and when it is less than 1 second (failure), it is indicated by "x".

[Aging resistance]
A conductor was extracted from the electric wire to prepare a tubular piece, and a tensile test was performed. The test was carried out at a distance between the marked lines of 25 mm and a tensile speed of 50 mm / min, and the tensile strength and the elongation at break were measured. The tensile test was performed at room temperature (25 ° C.) and normal humidity (relative humidity: 50%) according to UL758.
On the other hand, each of the electric wires was heat-treated at 180 ° C. for 2, 4, 7 or 10 days in a constant temperature bath. Using a tubular piece from which the conductor was extracted from the electric wire after the heat treatment, the tensile strength and the elongation at break were measured in the same manner as described above. For each of the measured tensile strength and elongation at break, the ratio of the tensile strength of the electric wire before the heat treatment to the elongation at break (residual tensile strength and residual elongation at break) was determined.
The obtained tensile strength and the residual ratio of tensile elongation were evaluated according to the following.
The tensile strength and the residual rate of tensile elongation after 10 days are both 80% or more: ◎
After 10 days, either the tensile strength or the residual ratio of tensile elongation is less than 80%, but after 7 days, both of these residual ratios are 80% or more: ○
After 7 days, either the tensile strength or the residual rate of tensile elongation is less than 80%, but after 4 days, both of these residual rates are 80% or more: ○ △
After 4 days, either the tensile strength or the residual rate of tensile elongation is less than 80%, but after 2 days, both of these residual rates are 80% or more: △
Either the tensile strength after 2 days or the residual rate of tensile elongation is 80% or less (failure): ×

[Moldability]
The moldability (extrusion moldability) of the silane crosslinkable resin composition was evaluated using the dry blends prepared in each of the above examples.
The dry blend prepared in each example was extruded and coated in the same manner as the extrusion coating except that the linear velocity was changed to obtain an electric wire.
In this extrusion coating, the moldability was evaluated according to the following evaluation criteria based on the maximum production speed (maximum linear velocity) that can be extruded and coated. Here, the maximum production speed that can be extruded and coated is the linear speed at which there is no appearance defect in the extruded coated coating layer and no lumps are observed, and it is assumed to be the highest.
When the maximum linear velocity is 150 mm / min or more, it is indicated by "◎", when it is 100 mm / min or more and less than 150 mm / min, it is indicated by "○", and it is 40 mm / min or more and less than 100 mm / min. If there was, it was indicated by "Δ", and if it was less than 40 mm / min (failed), it was indicated by "x".
Here, the poor appearance refers to foaming and so-called melt fracture, which is unevenness or roughness on the surface of the molded product. Regarding foaming, the presence or absence of foaming was confirmed in the appearance of the coating layer of the electric wire. Observation of foaming was performed visually. Here, "no foaming" means that no bubbles having a size of 0.05 mm or more are observed on the surface. Further, the lumps are gel lumps formed by cross-linking or aggregated lumps in which the raw materials are aggregated without being compatible with each other.

[Heat deformation test (heat resistance)]
The thermal deformation characteristics of the coating layer were measured for each electric wire. By this test, the degree of cross-linking reaction (heat resistance of the silane cross-linked resin molded product) can be evaluated.
The thermal deformation test was performed according to UL758. At a measurement temperature of 121 ° C., a load of 2.45 N was applied to each electric wire in the direction perpendicular to the longitudinal direction. At this time, the deformation rate of the coating layer ([(thickness of the coating layer before heating-thickness of the coating layer after heating) / thickness of the coating layer before heating] × 100) is less than 30%. "○", 30% or more and less than 50% was evaluated as "Δ", and 50% or more (failed) was evaluated as "x".

From the results in Tables 1 to 3, the following can be seen.
Comparative Example 1 using a catalyst masterbatch in which the content of the benzimidazole-based antiaging agent is within the range specified in the present invention but the content of the hydrazine-based heavy metal inactivating agent is too large is the preparation of the catalyst masterbatch. Foaming was observed in the foaming suppression test during time and secondary processing. Further, the maximum production speed that can be extruded is slow, and the silane crosslinkable resin composition is inferior in moldability.
In Comparative Example 2 using the catalyst masterbatch in which the content of the benzimidazole-based antiaging agent was too large, foaming was observed during the preparation of the catalyst masterbatch, and the moldability of the silane crosslinkable resin composition was inferior.
Comparative Example 3 using the catalyst masterbatch in which the content of the benzimidazole-based antiaging agent was too low was inferior in aging resistance.
Comparative Example 4 using a catalyst masterbatch in which the contents of the benzimidazole-based antiaging agent and the hydrazine-based heavy metal inactivating agent satisfy the range specified in the present invention but the MFR is too high is shown in the preparation of the catalyst masterbatch. In addition, foaming was observed in the foaming suppression test during the secondary processing. On the other hand, Comparative Example 5 using a catalyst masterbatch in which the contents of the benzimidazole-based antiaging agent and the hydrazine-based heavy metal inactivating agent satisfy the range specified in the present invention but the MFR is too low is a silane crosslinkable resin. The moldability of the composition was not sufficient.
Comparative Example 6 using the catalyst masterbatch in which the content of the silanol condensation catalyst was too small even though the antiaging agent and the MFR satisfied the range specified in the present invention was inferior in the heat resistance of the obtained electric wire. On the other hand, in Comparative Example 7 using the catalyst masterbatch in which the content of the silanol condensation catalyst was too large even if the range specified in the present invention was satisfied, the silane crosslinkable resin composition did not show sufficient moldability.
In Comparative Example 8 using the catalyst masterbatch in which the content of the benzimidazole-based antiaging agent was too large, poor appearance due to foaming was observed.

On the other hand, the catalysts of Examples 1 to 10 , 12, 15, 17 to 20, which contain a specific amount of a benzimidazole-based antiaging agent, a hydrazine-based heavy metal inactivating agent and a silanol condensation catalyst, and have an MFR in a specific range. In all master batches, foaming during pellet preparation is suppressed. Further, the electric wires of Examples 1 to 10, 12, 15, 17 to 20 in which the catalyst masterbatch of the present invention is used in combination with a silane graft resin in a specific ratio have excellent appearance, heat resistance and aging resistance. , Foaming is suppressed in the foaming suppression test during secondary processing. As described above, the catalyst masterbatch of Examples 1 to 10, 12, 15, 17 to 20 can be used in the silane cross-linking method to produce an electric wire having excellent appearance, heat resistance and aging resistance. Further, the silane crosslinkable resin composition using these catalyst master batches shows excellent moldability capable of forming a crosslinked body of the silane crosslinked resin while suppressing appearance defects and generation of lumps.
As described above, the catalyst masterbatch of the present invention can impart excellent heat resistance, aging resistance and appearance while reducing foaming even if it contains a relatively large amount of a benzimidazole-based antiaging agent. ..

Claims (9)

Silane coupling agent having a hydrolyzable silyl group is a silane crosslinking catalyst composition used in silane crosslinking grafting reaction silane-grafted resin,
15 to 30 parts by mass of a benzoimidazole-based antioxidant, 5 to 25 parts by mass of a hydrazine-based heavy metal inactivating agent, and 0.05 to 5 parts by mass of a silanol condensation catalyst are added to 100 parts by mass of a carrier resin containing a polyolefin resin. A catalyst composition for silane cross-linking, which is contained and has a melt flow rate of 0.1 to 7 g / 10 min at 190 ° C. and 2.16 kg. The catalyst composition for silane cross-linking according to claim 1, which contains 30 parts by mass or less of a phenolic antiaging agent. The catalyst composition for silane cross-linking according to claim 1 or 2, wherein the melt flow rate at 190 ° C. and 2.16 kg is 0.5 to 7 g / 10 min. The catalyst composition for silane cross-linking according to any one of claims 1 to 3, wherein the carrier resin contains 20% by mass or more of a styrene-based elastomer. A melt mixture of the silane cross-linking catalyst composition according to any one of claims 1 to 4 and a silane graft resin composition containing a base resin, and the base resin has a hydrolyzable silyl group. A silane crosslinkable resin composition containing a silane graft resin obtained by grafting a silane coupling agent. The silane crosslinkable resin composition according to claim 5, wherein the base resin contains 10% by mass or more of a styrene-based elastomer. The silane crosslinkable resin composition according to claim 5 or 6, which contains 10 to 400 parts by mass of an inorganic filler with respect to a total of 100 parts by mass of the carrier resin and the base resin of the silane crosslinking catalyst composition. A wiring material having a coating layer made of a cured product of the silane crosslinkable resin composition according to any one of claims 5 to 7. The wiring material according to claim 8, which is a heat-resistant electric wire or a cable.