JP7433771B2 - Catalyst composition for silane crosslinking, kit for preparing silane crosslinked resin molded body, and method for producing silane crosslinked resin molded body - Google Patents

Description

The present invention relates to a catalyst composition for silane crosslinking, a kit for preparing a silane crosslinked resin molded body, and a method for producing a silane crosslinked resin molded body.

Wiring materials such as insulated wires, tubes, cables, cords, optical fiber cores, or optical fiber cords (optical fiber cables) used in the electric/electronic equipment field and industrial field have a coating layer made of, for example, polyolefin resin. . By crosslinking the polyolefin resin forming this coating layer, the heat resistance of the coating layer can be improved.
As a method for crosslinking polyolefin resins, a silane crosslinking method is known, which has advantages such as not requiring special equipment. In the silane crosslinking method, first, a silane graft resin is prepared by grafting a silane coupling agent having a hydrolyzable silyl group and an unsaturated group onto a polyolefin resin in the presence of an organic peroxide. Next, the obtained silane graft resin is brought into contact with moisture in the presence of a silanol condensation catalyst to condense the hydrolyzable silyl groups. In this way, the polyolefin resin can be silane crosslinked.

When manufacturing wiring materials by the silane crosslinking method, a base resin composition containing a silane graft resin (silane masterbatch) and a silane crosslinking catalyst composition containing a silanol condensation catalyst (catalyst masterbatch) are usually used. use For example, Patent Document 1 uses a flame retardant compound containing a silane graft resin, a catalyst masterbatch formed by mixing a silanol condensation catalyst, specific polypropylene, and propylene wax.

Japanese Patent Application Publication No. 2014-196397 Japanese Patent Application Publication No. 2018-178029

2. Description of the Related Art In recent years, electrical and electronic devices have become smaller and lighter, and there is an increasing demand for smaller diameter wiring materials used in these devices. When manufacturing wiring materials that meet these requirements by extrusion molding using the silane crosslinking method described above, if the screw rotation speed of the extruder is the same, the diameter of the wiring material will be smaller than that of the wire material with a larger diameter. However, the speed at which the formed wiring material is extruded from the extruder becomes faster, and theoretically, the smaller the diameter of the wiring material, the faster the speed at which it is extruded from the extruder. However, there is a limit to the speed, so when the diameter of the wiring material is small, the screw rotation speed of the extruder is generally lowered to reduce the speed at which the formed wiring material is extruded from the extruder.
However, if the screw rotation speed of the extruder is lowered in this manner, the silane graft resin will remain in the cylinder of the extruder for a long time, and the silane will be more likely to crosslink due to the heat of the cylinder. When the silane graft resin is cross-linked with silane during extrusion molding, gel-like lumps (agglomerates) are formed, which deteriorates the appearance of the resulting wiring material.

In this regard, in Patent Document 2, by configuring the silane crosslinking catalyst composition to contain a specific resin component and mineral oil, the silane graft resin and the silane crosslinking catalyst composition are formed in the cylinder of an extruder. When mixing, the materials to be mixed become slippery, making it difficult for them to adhere to the inner wall of the cylinder, so even if the extruder screw rotation speed is low (for example, screw rotation speed 10 rpm) It is stated that a molded article having an excellent appearance without any blemishes can be obtained.
As a result of further research on such catalyst compositions for silane crosslinking, the present inventors have found that an excellent product with no lumps even when the silane graft resin and the catalyst composition for silane crosslinking are mixed at a lower screw rotation speed. We were able to find a catalyst composition for silane crosslinking that allows a molded article with a good appearance to be obtained.

The present invention solves the above problems and produces a silane crosslinked resin molded product that has an excellent appearance even when the screw rotation speed of the extruder is low when used in the silane crosslinking method for crosslinking silane grafted resin. An object of the present invention is to provide a catalyst composition for silane crosslinking, a kit for preparing a silane crosslinked resin molded body, and a method for producing a silane crosslinked resin molded body, which can be manufactured.

In the silane crosslinking method, the present inventors use a catalyst composition containing a silanol condensation catalyst, a specific resin component, a mineral oil, and a filler as a catalyst composition for silanol condensation of a silane graft resin. It has been found that a silane crosslinked resin molded article having an excellent appearance can be produced not only when the screw rotation speed of the extruder is high, but also when the screw rotation speed is low. Based on this knowledge, the present inventors conducted further research and came up with the present invention.

That is, the object of the present invention was achieved by the following means.
<1> A silane crosslinking catalyst composition used for crosslinking a silane grafted resin grafted with a silane coupling agent having a hydrolyzable silyl group, the composition comprising:
A carrier resin (A) containing at least one resin component (A1) selected from a styrenic thermoplastic elastomer or an ethylene-α olefin copolymer rubber, and a mineral oil;
At least one filler (B) selected from halogen flame retardants and inorganic fillers;
a silanol condensation catalyst (C),
Contains
In addition to the resin component (A1), the carrier resin (A) includes at least one resin selected from ethylene-based copolymers including ethylene-α olefin copolymers, ethylene-acrylic rubbers, and high-density polyethylene resins. Contains component (A2),
The content of the mineral oil is 10 to 40% by mass in the carrier resin (A),
Containing 5 to 400 parts by mass of the filler per 100 parts by mass of the carrier resin (A),
The mixing ratio of the silanol condensation catalyst (C) is set to 0.02 to 0.5 parts by mass with respect to a total of 100 parts by mass of the silane graft resin and the carrier resin (A),
A mixing ratio of the carrier resin (A) to the silane graft resin is set to 18 to 35% by mass with respect to a total of 100% by mass of the silane graft resin and the carrier resin (A). Catalyst composition for silane crosslinking.
<2> The silane crosslinking according to <1>, which contains a total of 60 to 90 parts by mass of the resin component (A1) and the resin component (A2) in 100 parts by mass of the carrier resin (A). Catalyst composition for use.
<3> The silane crosslinking catalyst composition according to <1>, which contains 8 to 42 parts by mass of the resin component (A1) in 100 parts by mass of the carrier resin (A).
<4> The silane crosslinking catalyst according to any one of <1> to <3>, which contains 25 to 300 parts by mass of the filler based on 100 parts by mass of the carrier resin (A). Composition.
<5> The silane crosslinking catalyst according to any one of <1> to <3>, which contains 200 to 300 parts by mass of the filler based on 100 parts by mass of the carrier resin (A). Composition.
<6> A kit for preparing a silane crosslinked resin molded article, comprising a combination of a silane graft resin and the silane crosslinking catalyst composition according to any one of <1> to <5> .
<7> Step (b) of melt-mixing the silane graft resin and the silane crosslinking catalyst composition according to any one of <1> to <5> and then molding; A method for producing a silane crosslinked resin molded article, the method comprising: (c) contacting the molded article with water to crosslink it.

In addition, in this specification, a numerical range expressed using "~" means a range that includes the numerical values written before and after "~" as a lower limit value and an upper limit value.

According to the catalyst composition for silane crosslinking, the kit for preparing a silane crosslinked resin molded body, and the method for producing a silane crosslinked resin molded body of the present invention, when used in a silane crosslinking method, if the screw rotation speed of the extruder is high, Of course, even if the screw rotation speed is lowered, the formation of crosslinked products of the silane grafted resin can be suppressed, and a silane crosslinked resin molded article having an excellent appearance can be produced.

[Catalyst composition for silane crosslinking]
The silane crosslinking catalyst composition of the present invention is used for crosslinking a silane graft resin in which a silane coupling agent having a hydrolyzable silyl group is grafted. When this catalyst composition for silane crosslinking is used in combination with a silane graft resin, the hydrolyzable silyl group undergoes silanol condensation when preparing or molding a mixture of the silane graft resin and the catalyst composition for silane crosslinking. can be prevented.
Thereby, when the catalyst composition for silane crosslinking of the present invention is used in a silane crosslinking method in combination with a silane graft resin, it is possible to produce a silane crosslinked resin molded article having an excellent appearance.

The silane crosslinking catalyst composition of the present invention contains a carrier resin (A), a filler (B), and a silanol condensation catalyst (C). Each component will be explained below.

<Carrier resin (A)>
The carrier resin (A) contains at least one resin component (A1) selected from ethylene-α olefin copolymer rubber or styrene thermoplastic elastomer, and mineral oil.

- Resin component (A1) -
Ethylene-α-olefin copolymer rubber is an ethylene-α-olefin terpolymer (for example, a terpolymer of ethylene, α-olefin, and diene) having a repeating unit having an unsaturated group as a third component other than ethylene and α-olefin (propylene). original copolymers). In the present invention, either one or both of EPM and EPDM may be used as the ethylene-α olefin copolymer rubber. Examples of the α-olefin include, but are not limited to, 1-propylene, 1-butene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-decene, and 1-dodecene.

The ethylene-α-olefin copolymer rubber used in the present invention is not particularly limited as long as it is a rubber made of a copolymer of ethylene and the above-mentioned α-olefin. For example, ethylene-propylene copolymer rubber (EP rubber (EPM)) is a rubbery copolymer of ethylene and propylene. Here, the ethylene-α-olefin copolymer rubber refers to one whose ethylene component content is usually about 40 to 75% by mass. The ethylene component content in the ethylene-α-olefin 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.

Examples of ethylene-α olefin copolymer rubbers include "Mitsui EPT" (trade name, manufactured by Mitsui Chemicals) and "Nodel" (trade name, manufactured by Dow Chemical) (both ethylene-propylene copolymer rubbers). etc. can be mentioned.

The ethylene-α olefin copolymer rubber contained in the carrier resin may be one type or two or more types.

By containing the ethylene-α olefin copolymer rubber as a resin component, the ethylene-α olefin copolymer rubber absorbs the mineral oil described below contained in the silane crosslinking catalyst composition. When the silane crosslinking catalyst composition in such a state is melt-mixed with the silane graft resin during extrusion molding or injection molding, the mineral oil is uniformly dispersed and the molding material (silane) is coated on the inner wall of the cylinder of the molding machine. (a mixture of a graft resin and a silane crosslinking catalyst composition) becomes difficult to adhere to, and the generation of lumps during extrusion molding can be effectively suppressed. On the other hand, in the case of injection molding, the occurrence of so-called short shots can be suppressed by the same effect. Furthermore, bleed-out of mineral oil can also be suppressed.

The styrenic thermoplastic elastomer used in the present invention is a copolymer block of constituent components derived from an aromatic vinyl compound and a conjugated diene compound, and/or a block copolymer block mainly composed of constituent components derived from the above compounds. It is a hydrogenated product of a polymer or random copolymer.
The hydrogenated copolymer (hereinafter sometimes referred to as hydrogenated copolymer) preferably contains 5 to 70% by mass, more preferably 10 to 60% by mass, of a constituent derived from an aromatic vinyl compound. . This content can be determined, for example, by measuring the UV absorption spectrum with an ultraviolet spectrophotometer using a chloroform solution.
As the aromatic vinyl compound, one or more types can be selected from, for example, styrene, α-methylstyrene, vinyltoluene, p-tert-butylstyrene, and the like, with styrene being preferred. As the conjugated diene compound, for example, one or more types can be selected from butadiene, isoprene, 1,3-pentadiene, 2,3-dimethyl-1,3-butadiene, etc. Among them, butadiene, isoprene, or these A combination of these is preferred.

Examples of styrenic thermoplastic elastomers include SBS (styrene-butadiene-styrene block copolymer), SIS (styrene-isoprene-styrene block copolymer), SEBS (styrene-ethylene-butylene-styrene block copolymer: hydrogenated SBS), and SEEPS. Examples include (styrene-ethylene-ethylene-propylene-styrene block copolymer), SEPS (styrene-ethylene-propylene-styrene block copolymer: hydrogenated SIS), and HSBR (hydrogenated styrene-butadiene random copolymer).
As the styrenic thermoplastic elastomer, a binary or tertiary copolymer composed of a polystyrene block and an elastomer block having a polyolefin structure can be used.

Examples of styrenic thermoplastic elastomers include "Septon" (trade name, manufactured by Kuraray Corporation), "Tuftec" (trade name, manufactured by Asahi Kasei Chemicals Co., Ltd.), and "Dynalon" (trade name, manufactured by JSR Corporation). can.

The styrene thermoplastic elastomer contained in the carrier resin may be one type or two or more types.

By containing a styrene thermoplastic elastomer as a resin component, it is possible to effectively suppress the occurrence of lumps during extrusion molding. This suppressing effect increases as the amount of the styrenic thermoplastic elastomer increases. Further, in the injection molding method as well, if the residence time in the cylinder becomes long, short shots tend to cause poor appearance due to chipping or roughening of the surface of the molded product. However, by containing a styrene-based thermoplastic elastomer as the carrier resin (A), even when molded using an injection molding machine, the molding material (mixture of silane graft resin and silane crosslinking catalyst composition) remains inside the cylinder wall. This prevents short shots from occurring.

By containing a styrene thermoplastic elastomer as a resin component, the molding material (mixture of silane graft resin and silane crosslinking catalyst composition) can be used in extrusion molding as well as in the injection molding described above. It becomes difficult to adhere to the inside of the cylinder wall and can effectively suppress the occurrence of lumps during extrusion molding. Furthermore, when the styrene-based thermoplastic elastomer coexists, the compatibility of the mineral oil described below with the resin component improves, so that bleed-out of the mineral oil to the surface of the silane crosslinked resin molded product can be suppressed.

- Mineral oil -
The mineral oil used in the present invention is a mixed oil containing an oil having an aromatic ring, an oil having a naphthene ring, and an oil having a paraffin chain. Paraffinic oil means that the number of carbon atoms (CP) in the paraffin chain is, for example, 50% or more and less than 75% of the total number of carbons in the aromatic ring, naphthenic ring, and paraffinic chain, and the number of carbon atoms (CN) in the naphthenic chain is 20 or more and less than 40%, and the number of carbon atoms in the aromatic ring (CA) is 3 or more and less than 10%. Naphthenic oil is one in which CN is 40 or more and less than 60%, CP is 30% or more and less than 50%, and CA is 8% or more and less than 16%, and aromatic oil is CA is 16% or more.
As the mineral oil (rubber softener), paraffinic oil or naphthenic oil can be used, and paraffinic oil is preferable in terms of mechanical strength.
The mineral oil preferably exhibits a dynamic viscosity of 20 to 500 cSt at 40°C, a pour point of -10 to -15°C, and a flash point (COC) of 180 to 300°C.
Examples of mineral oils include "Diana Process Oil" (trade name, manufactured by Idemitsu Kosan Co., Ltd.), "Cosmo Neutral" (trade name, manufactured by Cosmo Oil Lubricants Co., Ltd.), and the like.

- Other resin components (A2) -
The other resin component (A2) used as the carrier resin is preferably a resin that is mixed (compatible) with the silane graft resin described below. For example, when the resin forming the silane graft resin is a polyolefin resin described below, it is usually preferable to use a polyolefin resin.
In the present invention, the carrier resin (A) is selected from the above resin component (A1) and an ethylene copolymer containing an ethylene -α olefin copolymer, an ethylene-acrylic rubber , and a high-density polyethylene resin. Contains at least one resin component (A2).

The ethylene copolymer used in the present invention includes, for example , ethylene-vinyl acetate copolymer, ethylene-(meth)acrylic acid ester copolymer, ethylene-(meth)acrylic acid copolymer, etc. alone, or An appropriate mixture can be used. By using these ethylene copolymers, flame retardance can be improved and flexibility can be imparted at the same time.

As long as the ethylene-vinyl acetate copolymer is a copolymer of ethylene and vinyl acetate, it may be an alternating copolymer in which an ethylene component and a vinyl acetate component are alternately polymerized; It may be a block copolymer in which a polymer block and a polymer block of a vinyl acetate component are bonded together, or it may be a random copolymer in which an ethylene component and a vinyl acetate component are randomly polymerized.
As the ethylene-vinyl acetate copolymer, it is preferable to use one having a vinyl acetate component content of 10 to 80% by mass. The content of the vinyl acetate component in the ethylene-vinyl acetate copolymer is preferably 12 to 70% by mass, more preferably 15 to 50% by mass, and even more preferably 17 to 45% by mass. Two or more types of resins having different contents of vinyl acetate components may be combined.
Examples of the ethylene-vinyl acetate copolymer include Evaflex (trade name, manufactured by DuPont Mitsui Polychemicals) and Levaprene (trade name, manufactured by Bayer).

The ethylene-(meth)acrylic ester copolymer includes both an ethylene-acrylic ester copolymer and an ethylene-methacrylic ester copolymer.
If the ethylene-(meth)acrylic ester copolymer is a copolymer of ethylene and (meth)acrylic ester, it may be an alternating copolymer or a block copolymer, like the above-mentioned ethylene-vinyl acetate copolymer. It may be either a polymer or a random copolymer. The (meth)acrylic acid ester component is not particularly limited, but preferably has an alkyl group having 1 to 4 carbon atoms, such as methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, butyl acrylate, etc. can be mentioned.
The content of the (meth)acrylic ester component, which is a copolymerization component of the ethylene-(meth)acrylic ester copolymer, is preferably 10 to 40% by mass. When this content is within the above range, high tensile strength can be maintained and flame retardancy can be imparted.

Examples of the ethylene-(meth)acrylate copolymer include ethylene-methyl acrylate copolymer, ethylene-ethyl acrylate copolymer, ethylene-methyl methacrylate copolymer, and ethylene-ethyl methacrylate copolymer. Examples include merging.
Examples of the ethylene-acrylic acid ester copolymer include Elvaloy (trade name, manufactured by DuPont Mitsui Polychemicals Co., Ltd.).
Examples of the ethylene-(meth)acrylic acid copolymer include Nucrel (trade name, manufactured by DuPont Mitsui Polychemicals Co., Ltd.).
The ethylene copolymer contained in the carrier resin may be one type or two or more types.

The ethylene-α-olefin copolymer used in the present invention includes, for example, a copolymer of ethylene and an α-olefin having 4 to 12 carbon atoms. Examples of the α-olefin include, but are not limited to, 1-propylene, 1-butene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-decene, and 1-dodecene. Specifically, the ethylene-α olefin copolymer includes LDPE (low density polyethylene), LLDPE (linear low density polyethylene), MDPE (medium density polyethylene), or polyethylene synthesized in the presence of a metallocene catalyst. Examples include resins, among which LLDPE synthesized in the presence of a metallocene catalyst is preferred.
The density of the ethylene-α olefin copolymer is not particularly limited, but is preferably 0.880 to 0.940 g/cm ³ , more preferably 0.900 to 0.930 g/cm ³ . When the density of the ethylene-α-olefin copolymer is within the above range, excellent mechanical properties can be imparted to the silane crosslinked resin molded product, and furthermore, the mineral oil described below will not bleed out easily and the silane crosslinked resin molded product will last for a long time. The appearance can be maintained. The density of the ethylene-α olefin copolymer can be measured by the method described in JIS K 6922-1.

Examples of the ethylene-α olefin copolymer include "Kernel" (trade name, manufactured by Japan Polyethylene Co., Ltd.), "Evolu" (trade name, manufactured by Prime Polymer Co., Ltd.), and "Sumikasen" (trade name, manufactured by Sumitomo Chemical Co., Ltd.). , "Engage" (trade name, manufactured by Dow Company), etc.

The ethylene-α olefin copolymer contained in the carrier resin may be one type or two or more types.

The ethylene-acrylic rubber used in the present invention is, for example, a binary copolymer of ethylene and methyl acrylate, or a terpolymer copolymerized with an unsaturated hydrocarbon having a carboxyl group in the side chain. Rubbers made of various copolymers such as
Examples of the ethylene acrylic rubber made of a binary copolymer include Baymac DP and Baymac DLS. Examples of the ethylene acrylic rubber made of a terpolymer include Baymac G, Baymac HG, Baymac LS, and Baymac GLS (trade names, all manufactured by DuPont Mitsui Polychemicals).

As the high density polyethylene resin (HDPE) used in the present invention, an ethylene homopolymer or the like can be used. The resin density of the high-density polyethylene resin is not particularly limited, but is preferably more than 0.940 g/cm ³ and less than 0.965 g/cm ³ , more preferably 0.945 to 0.960 g/cm ³ . The density of high-density polyethylene resin can be measured by the method described in JIS K 7112.
Furthermore, the melt flow rate (hereinafter referred to as MFR, which refers to a value measured under the conditions of a temperature of 190° C. and a load of 21.18 N in accordance with JIS K 7210) of high-density polyethylene resin is not particularly limited. , preferably 0.1 to 10 g/10 minutes, more preferably 0.8 to 5 g/10 minutes. If the MFR is too small, for example, the motor load of manufacturing equipment may become high, which may affect high-speed moldability.
Examples of high-density polyethylene resins include "Hi-ZEX" (trade name, manufactured by Prime Polymer Co., Ltd.), "Nipolon Hard" (trade name, manufactured by Tosoh Corporation), and "Novatec" (trade name, manufactured by Tosoh Corporation).
(manufactured by Nippon Polyethylene Co., Ltd.).

The high-density polyethylene resin contained in the carrier resin may be one type or two or more types.

The content of the carrier resin in the silane crosslinking catalyst composition is not particularly limited, but is preferably, for example, 30% by mass or more and less than 100% by mass, and more preferably 50 to 98% by mass.
In the present invention, the total content of the resin components contained in the carrier resin is not particularly limited, and is appropriately set within a range that satisfies the content of the carrier resin. For example, the total content in the carrier resin is preferably 60 to 90% by mass, more preferably 65 to 85% by mass.

In addition, when the resin component contains at least one selected from ethylene-based copolymers including ethylene -α-olefin copolymer, ethylene-acrylic rubber , and high-density polyethylene resin , ethylene -α-olefin copolymer The content of at least one selected from ethylene-based copolymers including polyester, ethylene-acrylic rubber , and high-density polyethylene resin is preferably 20 to 80% by mass, and 35 to 70% by mass in the resin component . It is more preferable that

The content rate of each of the above resin components in the carrier resin is not particularly limited, and is appropriately determined within a range that satisfies the above content rate.
For example, the content of the ethylene-α olefin copolymer in the carrier resin is preferably 20 to 80% by mass, more preferably 30 to 60% by mass. If this content is too high, bumps are likely to occur.
The content of the high density polyethylene resin in the carrier resin is preferably 0 to 80% by mass, more preferably 0 to 60% by mass .

The content of mineral oil in the carrier resin is preferably 10 to 40% by mass. When the content of mineral oil is within the above range, it is possible to suppress the occurrence of lumps and also to prevent the mineral oil from bleeding out. As a result, a silane crosslinked resin molded article having an excellent appearance can be produced.

<Filler (B)>
The filler (B) is at least one selected from halogen flame retardants, antimony trioxide, and inorganic fillers.

- Halogen flame retardants -
The halogen-based flame retardant preferably has a high content of halogen atoms (for example, preferably 65% by mass or more, more preferably 80% by mass or more in the flame retardant), and the higher the content, the better the flame retardant. properties can be imparted to flame-retardant crosslinked resin compositions. The content of halogen atoms can be measured using, for example, energy dispersive fluorescent X-ray (EDX), combustion ion chromatography, or the like.
The brominated flame retardant is not particularly limited as long as it excludes polybromophenyl ether and polybromophenyl, and includes those commonly used in flame-retardant resin compositions. Examples include organic bromine-containing flame retardants such as brominated ethylene bisphthalimide compounds, bisbrominated phenyl terephthalamide compounds, brominated bisphenol compounds, or 1,2-bis(bromophenyl)ethane compounds. Among these, 1,2-bis(bromophenyl)ethane is preferred, and its commercially available products include, for example, Cytex (trade name, manufactured by Albemarle) and Firemaster (trade name, manufactured by Chemtura Japan).

- Antimony trioxide -
Antimony trioxide can be used in combination with a halogen flame retardant as a flame retardant aid for the halogen flame retardant. When the flame-retardant cross-linked resin composition of the present invention contains antimony trioxide, the flame retardance of the flame-retardant cross-linked resin composition can be further improved.
Examples of antimony trioxide include PATOX-C, PATOX-M, PATOX-K (all trade names, manufactured by Nippon Seiko Co., Ltd.), AT3, AT-3CN, AT-3TL (HB) (all trade names, (manufactured by Suzuhiro Chemical Co., Ltd.) and antimony trioxide (manufactured by Toyota Tsusho Company).
One type of antimony trioxide may be used, or two or more types may be used in combination.

- Inorganic filler -
In the present invention, the inorganic filler is particularly limited as long as it has a site on its surface that can be chemically bonded to a reactive site such as a silanol group of a silane coupling agent through a hydrogen bond, a covalent bond, or an intermolecular bond. It can be used without In this inorganic filler, sites that can chemically bond with the reactive site of the silane coupling agent include OH groups (OH groups such as hydroxyl groups, water molecules containing water or crystal water, and carboxy groups), amino groups, and SH groups. It will be done.

Inorganic fillers are not particularly limited, and include, for example, aluminum hydroxide, magnesium hydroxide, calcium carbonate, magnesium carbonate, calcium silicate, magnesium silicate, calcium oxide, magnesium oxide, aluminum oxide, aluminum nitride, aluminum borate whiskers, Examples include metal hydrates such as hydrated aluminum silicate, hydrated magnesium silicate, basic magnesium carbonate, hydrotalcite, talc, and other compounds having a hydroxyl group or water of crystallization. In addition, boron nitride, silica (crystalline silica, amorphous silica, etc.), carbon, clay, zinc oxide, tin oxide, titanium oxide, molybdenum oxide, antimony trioxide, silicone compounds, quartz, zinc borate, white carbon, Examples include zinc borate, zinc hydroxystannate, zinc stannate, and the like.

As the inorganic filler, a surface-treated inorganic filler whose surface is treated with a silane coupling agent or the like can be used. For example, Kisuma 5L, Kisuma 5P (all brand names, magnesium hydroxide, manufactured by Kyowa Chemical Industry Co., Ltd., etc.) are examples of the silane coupling agent surface-treated inorganic filler. The amount of surface treatment of the inorganic filler with the silane coupling agent is not particularly limited, but is, for example, 3% by mass or less.
Among these inorganic fillers, at least one selected from the group consisting of silica, aluminum hydroxide, magnesium hydroxide, and calcium carbonate is preferred.
One type of inorganic filler may be used alone, or two or more types may be used in combination.

When the inorganic filler is a powder, the average particle size of the inorganic filler is preferably 0.2 to 10 μm, more preferably 0.3 to 8 μm, even more preferably 0.4 to 5 μm, and particularly 0.4 to 3 μm. preferable. When the average particle size is within the above range, the retention effect of the silane coupling agent will be high and the heat resistance will be excellent. Furthermore, the inorganic filler is less likely to cause secondary aggregation when mixed with the silane coupling agent, resulting in an excellent appearance. The average particle size is determined by dispersing the inorganic filler in alcohol or water and using an optical particle size measuring device such as a laser diffraction/scattering type particle size distribution measuring device.

<Silanol condensation catalyst (C)>
The silanol condensation catalyst (C) functions to cause (promote) a silanol condensation reaction of hydrolyzable silyl groups derived from a silane coupling agent in the silane graft resin described below in the presence of moisture. Based on the action of this silanol condensation catalyst, the resins forming the silane graft resin are crosslinked with each other via the silane coupling agent. Therefore, the obtained silane crosslinked resin molded product has excellent heat resistance and, if necessary, strength.
The silanol condensation catalyst used in the present invention is not particularly limited, and examples thereof include organic tin compounds, metal soaps, platinum compounds, and the like. Specifically, dibutyltin dilaurate, dioctyltin dilaurate, dibutyltin dioctiate, dibutyltin diacetate, zinc stearate, lead stearate, barium stearate, calcium stearate, sodium stearate, lead naphthenate, lead sulfate, zinc sulfate, Examples include organic platinum compounds.

The content of the silanol condensation catalyst in the silane crosslinking catalyst composition is not particularly limited, and for example, it is preferably 0.01 to 10% by mass, more preferably 0.1 to 2.0% by mass. However, the content of the silanol condensation catalyst is not limited to the above range, but can be determined as appropriate, taking into consideration the mixing ratio with the silane grafted resin used together, the required characteristics of the silane crosslinked resin molded product, etc. . Specifically, when mixing with the silane graft resin, preferably 0.02 to 0.5 parts by mass, more preferably 0.05 to 0 parts by mass, based on a total of 100 parts by mass of the silane graft resin and carrier resin. The content of the silanol condensation catalyst in the catalyst composition for silane crosslinking and the mixture of the catalyst composition for silane crosslinking with respect to the silane graft resin so as to be .4 parts by mass, more preferably 0.08 to 0.3 parts by mass. The percentage is set.
By setting the content of the silanol condensation catalyst in the silane crosslinking catalyst composition within the above range, it is possible to suppress the occurrence of lumps during molding. Furthermore, the silanol reaction (crosslinking reaction) proceeds rapidly upon contact with water (step (c) described below), thereby imparting excellent heat resistance and, if necessary, strength to the silane crosslinked resin molded product.

<Additives>
The silane crosslinking catalyst composition contains various additives commonly used in electric wires, electric cables, electric cords, automobile parts, OA equipment, building parts, miscellaneous goods, sheets, foams, tubes, and pipes. , may be contained as appropriate within a range that does not impair the desired effect. Examples of such additives include crosslinking aids, antioxidants, lubricants, metal deactivators, flame retardants (assistants), and resins other than the above resin components.
The crosslinking aid refers to a compound that forms a partially crosslinked structure with a base resin that forms the silane graft resin described below in the presence of an organic peroxide. Examples include polyfunctional compounds.
Examples of the antioxidant include, but are not particularly limited to, amine antioxidants, phenol antioxidants, sulfur antioxidants, and the like.
Examples of the lubricant include hydrocarbons, siloxanes, fatty acids, fatty acid amides, esters, alcohols, metal soaps, and the like.

<Method for producing silane crosslinking catalyst composition>
The catalyst composition for silane crosslinking is prepared by heating and mixing (kneading) a carrier resin, a silanol condensation catalyst, and, if necessary, various additives. The heating temperature can be set higher than the melting temperature of the carrier resin, and is preferably set to, for example, 150 to 230°C. Other conditions, such as mixing time, can be set as appropriate.
As the mixing method, any method commonly used for rubber, plastic, etc. can be employed without particular limitation. As the mixing device, for example, a single screw extruder, a twin screw extruder, a roll, a Banbury mixer, or various kneaders can be used.

<Silane graft resin>
Next, the silane graft resin preferably used in combination with the silane crosslinking catalyst composition of the present invention will be explained.
The silane graft resin is formed from a silane coupling agent having a hydrolyzable silyl group and a base resin, and is a resin obtained by a graft reaction of the silane coupling agent to the base resin.
In this silane graft resin, the graft reaction amount of the silane coupling agent is not particularly limited. Usually, the amount of graft reaction that can be obtained by reacting the silane coupling agent and the base resin in the amount described later may be sufficient.

- Base resin -
The base resin contains a grafting reaction site of the silane coupling agent and a site that can undergo a grafting reaction in the presence of an organic peroxide, such as an unsaturated bond site of a carbon chain, a carbon atom having a hydrogen atom in the main chain or Examples include polymeric resins having terminal ends. Preferably, such a base resin includes a polyolefin resin.
The polyolefin resin is not particularly limited as long as it is a resin made of a polymer obtained by polymerizing or copolymerizing a compound having an ethylenically unsaturated bond, and may include any known resins conventionally used in resin compositions. can be used. For example, in addition to the above-mentioned resin components used in the carrier resin, resins such as polyethylene, ethylene copolymers having an acid copolymerization component or an acid ester copolymerization component, or rubbers or elastomers thereof may be mentioned. It will be done. Also included are acid-modified resins obtained by modifying these resins with unsaturated carboxylic acids. Examples of the ethylene copolymer resin having an acid copolymerization component or an acid ester copolymerization component include ethylene-vinyl acetate copolymer, ethylene-(meth)acrylic acid copolymer, and ethylene-(meth)acrylic acid. Examples include alkyl copolymers.
The base resin may contain the above-mentioned mineral oil.

- Silane coupling agent -
As a silane coupling agent for forming a silane graft resin, a grafting reaction site (group or atom ) and a hydrolyzable silyl group capable of silanol condensation, there is no particular limitation. Examples of such silane coupling agents include silane coupling agents conventionally used in silane crosslinking methods. Among these, those having a vinyl group and an alkoxysilyl group at the end are preferred. Examples of such silane coupling agents include vinyltrimethoxysilane, vinyltriethoxysilane, vinyltributoxysilane, vinyldimethoxyethoxysilane, vinyldimethoxybutoxysilane, vinyldiethoxybutoxysilane, allyltrimethoxysilane, and allyltriethoxysilane. Silane, vinyl silanes such as vinyltriacetoxysilane, (meth)acryloxysilanes such as methacryloxypropyltrimethoxysilane, methacryloxypropyltriethoxysilane, methacryloxypropylmethyldimethoxysilane, and the like. Among them, vinyltrimethoxysilane or vinyltriethoxysilane is particularly preferred.
The silane coupling agent that forms the silane graft resin may be used alone or in combination of two or more.

As the silane graft resin, one synthesized by the method described below may be used, or a commercially available product may be used.
Commercially available products include Linkron (trade name, manufactured by Mitsubishi Chemical Corporation) and the like.

- Organic peroxide -
When synthesizing a silane graft resin, it is preferable to use an organic peroxide. The organic peroxide functions to generate radicals at least through thermal decomposition and to cause a graft reaction of the silane coupling agent to the base resin by a radical reaction. The organic peroxide is not particularly limited as long as it generates radicals, and for example, those with the general formula: R1-OO-R2, R3-OO-C(=O)R4, R5C(=O)-OO A compound represented by (C=O)R6 is preferred. Here, R1 to R6 each independently represent an alkyl group, an aryl group or an acyl group. Among R1 to R6 of each compound, it is preferable that all of them are alkyl groups, or that one of them is an alkyl group and the rest are acyl groups.

Examples of such organic peroxides include dicumyl peroxide (DCP), di-tert-butyl peroxide, 2,5-dimethyl-2,5-di-(tert-butylperoxy)hexane, ,5-dimethyl-2,5-di(tert-butylperoxy)hexyne-3,1,3-bis(tert-butylperoxyisopropyl)benzene,1,1-bis(tert-butylperoxy)-3 , 3,5-trimethylcyclohexane, n-butyl-4,4-bis(tert-butylperoxy)valerate, benzoyl peroxide, p-chlorobenzoyl peroxide, 2,4-dichlorobenzoyl peroxide, tert-butylperoxide Oxybenzoate, tert-butylperoxyisopropyl carbonate, diacetyl peroxide, lauroyl peroxide, tert-butylcumyl peroxide and the like can be mentioned. Among these, dicumyl peroxide, 2,5-dimethyl-2,5-di-(tert-butylperoxy)hexane, 2,5-dimethyl-2 ,5-di(tert-butylperoxy)hexyne-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 an organic peroxide of a single composition undergoes a decomposition reaction into two or more types of compounds at a certain temperature or temperature range when heated. means. Specifically, it refers to the temperature at which endotherm or exotherm begins when heated from room temperature at a temperature increase rate of 5° C./min in a nitrogen gas atmosphere according to thermal analysis such as DSC method.

The silane graft resin is obtained by reacting a base resin and a silane coupling agent at a temperature higher than the decomposition temperature of the organic peroxide. Specific reaction conditions include the melt mixing conditions of step (a) described below.

<Silane crosslinkable resin composition>
In the present invention, the silane graft resin may be used alone or as a composition with each component described below. A composition containing a silane graft resin is referred to as a silane crosslinkable resin composition (silane MB (masterbatch)).
Components contained in the silane crosslinkable resin composition are not particularly limited, but include inorganic fillers, the various additives described above, and the like. Further, it may contain a decomposed product of an organic peroxide that causes a silane graft reaction.

The silane crosslinkable resin composition can be prepared by mixing the silane graft resin and various components, or can also be prepared as in step (a) described below. In the present invention, it is preferable to prepare as in step (a) described below.

[Kit for preparing silane cross-linked resin moldings]
The kit for preparing a silane crosslinked resin molded article of the present invention is formed by combining a silane graft resin and the above-mentioned catalyst composition for silane crosslinking of the present invention.
In the kit for preparing a silane crosslinked resin molded article of the present invention, the silane graft resin may be used alone or in a mixture with other components, for example, as the above-mentioned silane crosslinkable resin composition. Further, the silane crosslinking catalyst composition of the present invention may be used as one composition, or the carrier resin (A) and the silanol condensation catalyst (C) may be used in separate forms.
This kit for preparing a silane crosslinked resin molded article may be used in any manufacturing method as long as it is a method for manufacturing a silane crosslinked resin molded article. Preferably, it is used in step (b) in the method for producing a silane crosslinked resin molded article described below.
In the silane crosslinked resin molded preparation kit of the present invention, the mixing ratio of the silane graft resin and the silane crosslinking catalyst composition is not particularly limited, but the mixing ratio described in step (b) below is preferable.

[Method for producing silane crosslinked resin molded product]
Next, a method for producing a silane crosslinked resin molded article using the silane crosslinking catalyst composition of the present invention will be explained.
The method for producing a silane crosslinked resin molded article includes a step (b) of melt-mixing a silane graft resin and the silane crosslinking catalyst composition of the present invention and then molding the molded article, and bringing the obtained molded article into contact with moisture to crosslink it. and step (c).

<One aspect of the method for producing a silane crosslinked resin molded article>
In the present invention, as described above, the silane crosslinking catalyst composition contains a filler, but the silane graft resin may also contain an inorganic filler or the like. That is, in one embodiment of the method for producing a silane crosslinked resin molded article, a silane crosslinkable resin composition containing an inorganic filler may be used as the silane graft resin. In this case, prior to step (b), step (a) of synthesizing the silane graft resin in the presence of an inorganic filler is provided. That is, a preferred embodiment of the method for producing a silane crosslinked resin molded article when using a silane crosslinkable resin composition containing an inorganic filler includes the following steps (a) to (c).
Step (a): When the total of the silane graft resin and the carrier resin to be mixed in step (b) is 100 parts by mass, the base resin and 0.003 to 0.3 parts by mass of organic peroxide, A step of melt-mixing 0.5 to 400 parts by mass of an inorganic filler and more than 2 parts by mass and up to 15.0 parts by mass of a silane coupling agent at a temperature equal to or higher than the decomposition temperature of the organic peroxide. Step (b): Step (c) of melt-mixing the silane crosslinkable resin composition obtained in step (a) and the silane crosslinking catalyst composition of the present invention and then molding the molded article obtained in step (b) with moisture. Crosslinking process by contacting with

In step (a), the amount of organic peroxide blended is 0.003 to 0.3 parts by mass, preferably 0.005 to 0.3 parts by mass, and 0.005 to 0.3 parts by mass, based on the total 100 parts by mass. 0.005 to 0.1 part by mass is more preferable. By controlling the blending amount of the organic peroxide within the above range, the graft reaction can be carried out within an appropriate range, and a silane crosslinkable resin composition with excellent extrudability while suppressing the generation of lumps can be prepared. can.

The blending amount of the inorganic filler is 0.5 to 400 parts by weight, preferably 30 to 280 parts by weight, based on the above-mentioned total of 100 parts by weight. By setting the 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.
The blending amount of the silane coupling agent is more than 2.0 parts by mass and 15.0 parts by mass or less, preferably 3 to 12.0 parts by mass, and 4 to 12.0 parts by mass out of the total 100 parts by mass. More preferred. By controlling 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 article.

In this aspect, "melting and mixing the base resin, organic peroxide, inorganic filler, and silane coupling agent" does not specify the mixing order when melt-mixing; This means that they may be mixed.
In this embodiment, it is preferable that the above-mentioned components are melt-mixed by the following steps (a-1) and (a-2).
Step (a-1): A step of preparing a mixture by mixing at least an inorganic filler and a silane coupling agent Step (a-2): The mixture obtained in step (a-1) and the base resin are mixed with an organic filter. A process of melting and mixing in the presence of an oxide at a temperature above the decomposition temperature of the organic peroxide.

The method of mixing the inorganic filler and the silane coupling agent (step (a-1)) is not particularly limited, and wet mixing or dry mixing may be used. In this embodiment, dry mixing is preferred, in which the silane coupling agent is mixed with the inorganic filler with or without heating. When the silane graft resin contains an inorganic filler, the silane coupling agent premixed in this way exists so as to surround the surface of the inorganic filler, and part or all of it is adsorbed or absorbed by the inorganic filler. Join. This makes it possible to reduce volatilization of the silane coupling agent during subsequent melt mixing. Dry mixing is preferably a method in which the inorganic filler and silane coupling agent are mixed for several minutes to several hours at a temperature below the decomposition temperature of the organic peroxide, preferably at room temperature (25° C.).
The organic peroxide only needs to be present when performing the step (a-2), and may be mixed in the step (a-1) or in the step (a-2).

Next, the mixture obtained in step (a-1) and the base resin are melt-mixed (step (a-2)).

In step (a-2), the temperature at which the above components are melt-mixed is higher than the decomposition temperature of the organic peroxide, preferably 150 to 230°C. Other mixing conditions, such as mixing time, can be set as appropriate. As a result, the organic peroxide decomposes and acts on the melted components, and the grafting reaction of the silane coupling agent to the base resin proceeds.
The mixing method is not particularly limited as long as it is a method commonly used for rubber, plastic, etc. The mixing device is appropriately selected depending on, for example, the amount of inorganic filler blended. As a mixing device, a single-screw extruder, a twin-screw extruder, a roll, a Banbury mixer, or various types of kneaders are used. In view of the dispersibility of the resin component and the stability of the crosslinking reaction, it is preferable to use a closed mixer such as a Banbury mixer or various kneaders.

In step (a), the blending amount of the above-mentioned additives etc. that can be used in addition to the above-mentioned components is appropriately set within a range that does not impair the object of the present invention. These additives may be mixed in any of the steps above.

In this way, step (a) can be performed to prepare a silane crosslinkable resin composition containing a silane grafted resin.

In step (a-2), the silane coupling agent is graft-reacted to the base resin at least in the following manner. If the silane coupling agent is weakly bonded or adsorbed to the inorganic filler in the above step (a-1), the silane coupling agent is desorbed from the inorganic filler and the base resin is removed in step (a-2). Reacts to grafting. Furthermore, the silane coupling agent that has been strongly bonded or adsorbed to the inorganic filler undergoes a graft reaction with the base resin while maintaining the bond to the inorganic filler.

In a preferred embodiment of the above-mentioned manufacturing method, the silane crosslinking catalyst composition of the present invention is prepared, for example, by the method described above.

In a preferred embodiment of the above manufacturing method, the silane crosslinkable resin composition obtained in step (a) and the silane crosslinking catalyst composition of the present invention are mixed and then molded (step (b)).
The method of mixing the silane crosslinking resin composition and the silane crosslinking catalyst composition of the present invention is not particularly limited. For example, mixing can be performed in the same manner as the melt mixing in step (a-2). The melting temperature is appropriately selected depending on the melting temperature of the base resin or carrier resin, and is, for example, preferably 80 to 250°C, more preferably 100 to 240°C. Other conditions, such as mixing time, can be set as appropriate. In step (b), in order to avoid a silanol condensation reaction, it is preferable that the mixed state of silane MB and silanol condensation catalyst is not kept at a high temperature for a long time.

In a preferred embodiment of the above manufacturing method, the silane crosslinking resin composition and the silane crosslinking catalyst composition of the present invention can be dry blended before being melt-mixed. The dry blending method and conditions are not particularly limited, and include, for example, the dry blending in step (a-1) and its conditions.

In a preferred embodiment of the above manufacturing method, the mixing ratio of the silane crosslinking resin composition and the silane crosslinking catalyst composition of the present invention is preferably adjusted 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 0.02 parts by mass based on the total of 100 parts by mass of the silane graft resin in the silane crosslinking resin composition and the carrier resin in the silane crosslinking catalyst composition of the present invention. It is preferable to set the amount to 5 parts by mass ( see Examples described later). That is, the silane crosslinking catalyst composition of the present invention and the silane crosslinkable resin composition are mixed at a ratio of 0.02 to 0.5 parts by mass of the silanol condensation catalyst based on the above total of 100% by mass. is preferred. When the mixing ratio of the silanol condensation catalyst is within this range, the generation of lumps can be effectively suppressed, and the crosslinking reaction can be sufficiently progressed in the step described below. Therefore, in addition to the appearance, high heat resistance can be imparted to the obtained silane crosslinked resin molded article. The preferred mixing ratio of the silanol condensation catalyst is as described above.
Here, when using a silane crosslinkable resin composition, the amount (parts by mass) of the silane graft resin is the total amount of the base resin and the silane coupling agent in the silane crosslinkable resin composition.

The mixing ratio of the carrier resin is set at 5 to 60% by mass based on the total of 100% by mass of the silane graft resin in the silane crosslinkable resin composition and the carrier resin in the silane crosslinking catalyst composition of the present invention. It is preferable that That is, it is preferable that the carrier resin is mixed with the silane crosslinkable resin composition at a ratio of 5 to 60% by mass relative to the above-mentioned 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 crosslinking reaction can be sufficiently progressed in the step described below. The mixing ratio of the carrier resin is more preferably set to 15 to 40% by mass, and even more preferably set to 18 to 35% by mass ( see Examples below).

In a preferred embodiment of the above-mentioned manufacturing method, the melt-mixing of the above-mentioned step (a) and step (b) can be performed simultaneously or continuously.

In step (b), the mixture thus obtained is shaped.
This molding step only needs to be able to mold the mixture, and appropriate molding methods and molding conditions are selected depending on the form of the resin crosslinked molded product. Examples of the molding method include extrusion molding using an extruder, extrusion molding using an injection molding machine, and molding using other molding machines.
Extrusion molding is preferably applied when the resin crosslinked 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, extrusion speed (take-off speed), and other conditions, but is approximately 120 to 150°C for the cylinder part and approximately 160 to 180°C for the crosshead part (dice temperature). It is preferable to set it to .
In a preferred embodiment of the above manufacturing method, extrusion molding can be performed at a lower speed than the normally set screw rotation speed. A low screw rotation speed is effective when molding thin-diameter wiring materials, etc. For example, the screw rotation speed can be set to 30 rpm or less, preferably 20 rpm or less.

In step (b), the molding step can be performed simultaneously or consecutively with the mixing step. That is, one embodiment of melt mixing in the mixing step includes, for example, an embodiment in which the molding materials are melt mixed during or immediately before extrusion molding. For example, the silane crosslinking resin composition and the silane crosslinking catalyst composition of the present invention may be mixed at room temperature or high temperature (in an unmolten state), and then introduced into a molding machine and melt-mixed. Alternatively, the silane crosslinking resin composition and the silane crosslinking catalyst composition of the present invention 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 a silane crosslinking resin composition and a silane crosslinking catalyst composition of the present invention is melt-mixed in a coating device, and then extrusion coated on the outer peripheral surface of a conductor or the like. A series of steps can be employed to mold it into a desired shape.
As described above, a mixture is prepared by dry blending the silane crosslinking resin composition and the silane crosslinking catalyst composition of the present invention, and this mixture is introduced into a molding machine and molded to form a crosslinkable resin molded article. is obtained.

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 subjected to silanol condensation. Practically speaking, partial crosslinking (partial crosslinking) is unavoidable when melt-mixing is performed in step (b), but the appearance of the resulting crosslinkable resin molded article must not be deteriorated. Furthermore, it is preferable that at least the moldability during molding is maintained.
In one preferred embodiment of the above-mentioned manufacturing method, some of the hydrolyzable silyl groups may be bonded to or adsorbed to an inorganic filler. In other words, the crosslinkable resin molded article is composed of a silane grafted resin grafted with a silane coupling agent bound to or adsorbed to an inorganic filler by a hydrolyzable silyl group, and a silane grafted resin to which a silane coupling agent is not bound to or adsorbed to an inorganic filler by a hydrolyzable silyl group. It contains a silane grafted resin grafted with a coupling agent.

The crosslinkable resin molded article obtained in step (b) is turned into a (final) crosslinked silane crosslinked resin molded article by carrying out step (c).
In a preferred embodiment of the above manufacturing method, the crosslinkable resin molded article is brought into contact with water (step (c)). As a result, the hydrolyzable silyl group of the silane coupling agent is hydrolyzed into silanol, and the hydroxyl groups of the silanol are condensed with each other by the silanol condensation catalyst present in the molded article, resulting in a crosslinking reaction.
The treatment itself in step (c) can be performed by a conventional method. The above condensation reaction proceeds simply by storing at room temperature. Therefore, in step (c), there is no need to actively bring the crosslinkable resin molded article into contact with water. In order to promote this condensation reaction, the crosslinkable resin molded article can also be brought into contact with water. For example, methods of actively bringing the material into contact with water, such as immersion in hot water, placing it in a heat-and-moisture tank, and exposing it to high-temperature steam, can be employed. Further, at that time, pressure may be applied to allow moisture to penetrate inside.

In this way, a silane crosslinked resin molded article is produced. This silane crosslinked resin molded article contains a crosslinked resin crosslinked with the above-mentioned silane graft resin.
One form of the silane crosslinked resin molded article is considered to contain the following resin. When the silane graft resin contains an inorganic filler, the silane coupling agent that is detached from the inorganic filler and grafted onto the base resin undergoes a crosslinking reaction, resulting in bonding (crosslinking) through the silane coupling agent. Contains base resin. In addition, the silane coupling agent graft-reacted to the base resin while maintaining the bond with the inorganic filler is difficult to crosslink and contains the base resin bonded to the inorganic filler via the silane coupling agent. Silane crosslinked resin molded articles containing these resins have not only excellent appearance but also high heat resistance and strength.

<Another embodiment of the method for producing a silane crosslinked resin molded article>
In another embodiment of the method for producing a silane crosslinked resin molded article, the above steps (b) and (c) are performed using the silane crosslinking catalyst composition of the present invention and a silane graft resin.
In another embodiment, step (b) and step (c) are the same as the above embodiment except that a silane graft resin is used instead of the silane crosslinkable resin composition.

The catalyst composition for silane crosslinking of the present invention can be used in a silane crosslinking method in combination with a silane graft resin (silane MB), and can be used not only when the screw rotation speed of the extruder is high but also when the screw rotation speed is low. , it is possible to produce a silane crosslinked resin molded article with excellent appearance. The reason why the obtained silane crosslinked resin molded product has an excellent appearance is not yet clear, but the fact that the silane crosslinking catalyst composition contains a filler makes it easier to melt and mix the silane graft resin and the silane crosslinking catalyst composition. In addition, the filler in the catalyst composition for silane crosslinking adsorbs (bonds) the silane coupling agent remaining in the silane graft resin, so there is no excess due to the remaining silane coupling agent during preparation or molding. This is thought to be due to the ability to suppress the crosslinking reaction.
In addition, when mixing the silane graft resin and the silane crosslinking catalyst composition, the silane graft resin and the silane crosslinking catalyst composition are not mixed at a uniform concentration from the beginning, and the silane graft resin is not mixed in the initial stage of mixing. On the other hand, the concentration of the silane crosslinking catalyst composition may be uneven, and the crosslinking reaction may occur more than necessary in areas where the concentration is high, resulting in the formation of spots. However, when the catalyst composition for silane crosslinking contains a filler as in the present invention, the concentration of the silanol condensation catalyst in the catalyst composition for silane crosslinking is diluted by the filler. This is also considered to be because the concentration of the silanol condensation catalyst is not so high even in the areas where the concentration of the catalyst composition is high, and the crosslinking reaction does not occur more than necessary.

Furthermore, by containing a specific resin component and mineral oil, the catalyst composition for silane crosslinking of the present invention imparts lubricity to the molding material, making it difficult to adhere to the inner wall of the cylinder and making it smooth and smooth. This is thought to be one of the reasons why a molded article with an excellent appearance can be obtained.
The adsorption (bonding) effect of the silane coupling agent by the filler contained in such a catalyst composition for silane crosslinking, the dilution effect of the silanol condensation catalyst, and the effect of the mineral oil contained in the catalyst composition for silane crosslinking on the molding material. Combined with the effect of preventing the particles from adhering to the inner wall of the cylinder, the generation of lumps is suppressed even when the extruder screw rotation speed is lowered to about 2 to 6 rpm (see examples below), so it is an excellent product without lumps. It is thought that a molded article having a similar appearance can be obtained.

On the other hand, although commercially available silane grafted resins may not contain fillers, the silane crosslinking catalyst composition of the present invention contains fillers. If this method is used, there is also the advantage that there is no need to separately prepare and mix a filler when melt-mixing a commercially available silane graft resin and the silane crosslinking catalyst composition of the present invention.

<Application of manufacturing method of silane crosslinked resin molded article>
The method for producing a silane crosslinked resin molded product can be applied to the production of products (including semi-finished products, parts, and members) made of silane crosslinked resin molded products. This product may include a silane crosslinked resin molded product or may be a product consisting only of a silane crosslinked resin molded product. Such products include, for example, coating materials for wiring materials such as heat-resistant electric wires, heat-resistant cables, and optical fiber cables, and rubber molding materials (for example, glass run channels for automobiles, weather strips, rubber hoses, wiper blade rubber, and anti-vibration rubber). etc. Furthermore, the silane crosslinked resin molded product can be used as a substitute for polyolefin materials and EP rubber materials that have been conventionally crosslinked or chemically vulcanized by electron beam irradiation.

The manufacturing method of the present invention is suitably applied to manufacturing wiring materials.
When manufacturing a wiring material by extrusion molding using the silane crosslinking catalyst composition of the present invention, preferably, a molding material containing a mixture of the silane crosslinking catalyst composition of the present invention and a silane graft resin (silane MB) is extruded. The mixture is melted and mixed in a machine (extrusion coating equipment) and extruded onto the outer periphery of a conductor, etc. The conductor used may be a single wire or a twisted wire, and may be a bare wire or one coated with tin or enamel. Examples of the metal material forming the conductor include annealed copper, copper alloy, and aluminum. The thickness of the insulating layer formed around the conductor is not particularly limited, but is usually about 0.15 to 5 mm.
By using the silane crosslinking catalyst composition of the present invention, it is possible to manufacture electric wires with excellent appearance even if the diameter is reduced. In the present invention, the electric wire having a reduced diameter is not particularly limited as long as it has an outer diameter that is required for downsizing and weight reduction of recent electrical and electronic devices. For example, an electric wire having an outer diameter of less than 2 mm, preferably 1.5 mm or less may be mentioned.
Moreover, when the catalyst composition for silane crosslinking of the present invention is used, even in injection molding, silane crosslinked resin molded articles can be continuously molded as necessary while preventing the occurrence of short shots.

Hereinafter, the present invention will be explained in more detail based on Examples, but the present invention is not limited thereto.
In Tables I to IV, the numerical values relating to the blending amounts in each example represent parts by mass unless otherwise specified. Further, for each component, a blank column means that the amount of the corresponding component is 0 parts by mass.
In Tables I to IV, the styrenic thermoplastic elastomer and the ethylene-α olefin copolymer rubber are abbreviated as "styrene elastomer" and "EP rubber," respectively. Moreover, "catalyst MB" in the table represents a silane crosslinking catalyst composition.

Details of each component (compound) shown in Tables I to IV are shown below.
(1) Styrenic thermoplastic elastomer: Tuftec N504 (trade name, SEBS, content of components derived from aromatic vinyl compounds: 32% by mass, manufactured by Asahi Kasei Chemicals)
(2) Ethylene-α olefin copolymer rubber: Nordel 3720P (trade name, EPDM, ethylene content 70% by mass, manufactured by Dow)
(3) Ethylene-α olefin copolymer (polyethylene resin): Sumikacene CU5003 (trade name, LLDPE synthesized in the presence of a metallocene catalyst, density 0.928 g/cm ³ , manufactured by Sumitomo Chemical Co., Ltd.)
(4) Ethylene copolymer: VF120T (trade name, ethylene-vinyl acetate copolymer resin, manufactured by Ube Industries, Ltd.)
(5) Ethylene copolymer: NUC6510 (trade name, ethylene-ethyl acrylate copolymer resin, manufactured by NUC)
(6) Ethylene-acrylic rubber: Baymac DP (trade name, manufactured by DuPont Mitsui Polychemicals)
(7) High-density polyethylene: Hi-ZEX 5000H (trade name, density 0.958 g/cm ³ , MFR 0.10 g/10 min, manufactured by Prime Polymer Co., Ltd.)
(8) Polypropylene resin: PB222A (trade name, ethylene-propylene random copolymer, ethylene component content 2-6% by mass, MFR 0.8 g/10 min, manufactured by Sun Allomer Co., Ltd.)
(9) Mineral oil: Diana Process Oil 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.)
(10) Antioxidant: Irganox 1010 (trade name, pentaerythritol tetrakis [3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], manufactured by BASF)
(11) Magnesium hydroxide: Mugsys FK621 (trade name, manufactured by Kamishima Chemical Industry Co., Ltd.)
(12) Silica: Crystallite 5X (product name, manufactured by Ryumorisha)
(13) Silica: Aerosil 200 (trade name, manufactured by Nippon Aerosil Co., Ltd.)
(14) Calcium carbonate: Softon 1200 (trade name, manufactured by Bihoku Funka Kogyo Co., Ltd.)
(15) Calcined clay: SATINTONE SP33 (product name, manufactured by BASF)
(16) Talc: K-1 (product name, manufactured by Nippon Talc Co., Ltd.)
(17) Zinc borate: FirebrakeZB (trade name, manufactured by Borax)
(18) Zinc stannate: Flamtard H (trade name, manufactured by Nippon Light Metal Co., Ltd.)
(19) Halogen flame retardant: SAYTEX8010 (trade name, bromine flame retardant, manufactured by Albemarle)
(20) Antimony trioxide: Firecut AT-3TL (HB) (trade name, manufactured by Suzuhiro Chemical Co., Ltd.)
(21) Silanol condensation catalyst: ADEKA STAB OT-1 (trade name, dioctyltin dilaurate, manufactured by ADEKA)
(22) Silane crosslinkable LDPE: Linkron XCF730N (trade name, manufactured by Mitsubishi Chemical Corporation)
(23) Ethylene copolymer: VF120S (trade name, ethylene-vinyl acetate copolymer resin, manufactured by Ube Industries, Ltd.)
(24) Inorganic filler: Mugsys FK621 (trade name, magnesium hydroxide, manufactured by Kamishima Chemical Industry Co., Ltd.)
(25) Silane coupling agent: KBM1003 (trade name, vinyltrimethoxysilane, manufactured by Shin-Etsu Chemical Co., Ltd.)
(26) Organic peroxide: Perhexa 25B (trade name, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, decomposition temperature 179°C, manufactured by NOF Corporation)

(Examples 1 to 19 , Reference Examples 1 to 5 and Comparative Examples 1 to 3)
First, each component shown in the "Catalyst composition for silane crosslinking" column of Tables I to IV is melt-mixed at 200°C using a Banbury mixer, and then pelletized to form a catalyst composition for silane crosslinking (catalyst MB ) was obtained.
Next, the silane graft resin (silane crosslinkable LDPE) shown in the "Silane graft resin or silane MB" column of Tables I to IV and the silane crosslinking catalyst composition prepared above were dry blended. At this time, the mixing ratio for the silane graft resin is as shown in the "Silane graft resin or silane MB" column, and for the silane crosslinking catalyst composition, the mixing ratio after mixing with silane MB is shown in Tables I to Table IV. The mass proportion shown in the "Catalyst MB component" column (the total of the silane graft resin and carrier resin is 100 parts by mass) was set.
In the "Catalyst MB component after mixing with silane MB" column of Tables I to Table IV, the silanol condensation catalyst to be mixed with the silane graft resin is mixed with a total of 100 parts by mass of the silane graft resin and carrier resin (A). The ratio (indicated as "mixing ratio of silanol condensation catalyst" in each table) and the ratio of carrier resin (A) mixed with silane graft resin to 100% by mass of the total of silane graft resin and carrier resin (A) The mixing ratio (indicated as "mixing ratio of carrier resin" in each table) is shown. Note that the "mixing ratio of silanol condensation catalyst" is expressed in parts by mass, and the "mixing ratio of carrier resin" is expressed in mass %.

Next, a 25 mmφ extruder (ratio of screw effective length L to diameter D: L/D = 25) was installed at a die temperature of 160°C, below to the feeder side, C3 = 150°C, C2 = 140°C, C1 = 130°C. The extrusion temperature conditions were set as follows. The prepared dry blend was put into this extruder, melted and mixed, and extrusion coated onto a 0.8 mmφ conductor made of bare annealed copper wire to have an outer diameter of 1.2 mmφ and a thickness of 0.2 mm.
The obtained coated conductor was left in an environment of 23° C. and 50% relative humidity for 24 hours to produce an electric wire having a coating layer.

(Examples 20 to 23 )
First, each component shown in the "Catalyst composition for silane crosslinking" column in Table IV was melt-mixed at 200°C using a Banbury mixer, and then pelletized to obtain a catalyst composition for silane crosslinking (catalyst MB). Ta.
Silane MB was then prepared. The inorganic filler and silane coupling agent listed in the "Silane graft resin or silane MB" column of Table IV were charged into a 10L Henschel mixer made by Toyo Seiki in the mass proportions shown in Table IV, and the mixture was heated at room temperature (25°C). After mixing for a period of time, a powder mixture was obtained. Next, the prepared powder mixture and each component shown in the same column (resin component, mineral oil, and organic peroxide) were put into a 2L Banbury mixer made by Nippon Roll in the mass proportions shown in Table IV. , and melt-mixed for 10 minutes at a temperature (190° C.) higher than the decomposition temperature of the organic peroxide. Thereafter, the material was discharged at a temperature of 190° C. to obtain silane MB.
Next, the prepared silane MB and the prepared silane crosslinking catalyst composition were dry-blended at the mass ratio shown in Table IV (same as the mixing ratio explained in Example 1). An electric wire was manufactured in the same manner as in Example 1 using the obtained dry blend.

Each coated conductor obtained by the above extrusion molding or each manufactured electric wire was subjected to the following tests, and the results are shown in Tables I to IV.

<Appearance test>
In extrusion molding, the screw rotation speed of the extruder was varied to produce coated conductors of each Example and each Comparative Example. The surface of the coated conductor obtained at each screw rotation speed was observed to evaluate its appearance.
The evaluation was rated "A" (extremely high quality) when no spots were observed on the surface of the coating produced by setting the screw rotation speed to 2 rpm and the coating had a good appearance. If the surface of the coating made with the screw rotation speed set to 4 rpm had a good appearance and no spots were observed, it was classified as "B" (advanced). If no spots were observed and the appearance was good, it would be graded "C" (good), and if any spots could be seen on the surface of the coated conductor prepared at 8 rpm, it would be graded "D" (fail). did.

<Heating deformation test>
As a reference test, the heating deformation characteristics of the coating layer were measured for each electric wire. Through this test, the degree of crosslinking reaction (heat resistance of the silane crosslinked resin molded product) can be evaluated.
At a measurement temperature of 180° C., a load of 2.45 N was applied to each electric wire. At this time, a deformation rate of less than 15% is "AA" (extremely advanced), a deformation rate of 15% or more and less than 25% is "A" (advanced), and a deformation rate of 25% or more and less than 50% is "B". (good), and those with 50% or more were rated "D" (fail).

The following can be seen from the results in Tables I to IV.
When the screw rotation speed of the extruder is lowered to about 2 to 6 rpm, the electric wires of Comparative Examples 1 and 2 using silane crosslinking catalyst compositions containing no filler have poor appearance as silane crosslinked resin molded bodies. In addition, as in Comparative Example 3, even in a silane crosslinking catalyst composition that does not contain fillers, if the amount of silanol condensation catalyst is very small, spots can be observed on the surface of the coating prepared by setting the screw rotation speed to 6 rpm. Although it had a good appearance, the amount of silanol condensation catalyst was too small and the heat deformation properties deteriorated.
On the other hand, in Examples 1 to 23 , which used a catalyst masterbatch containing a specific resin component, mineral oil, and filler, the screw rotation speed of the extruder was lowered to about 2 to 6 rpm. It is possible to manufacture small diameter electric wires with excellent appearance even when In this way, even under manufacturing conditions where the screw rotation speed is low, the occurrence of lumps, which has been a problem in the past, is suppressed (formability is improved), and a small diameter electric wire with excellent appearance can be manufactured.
As shown in Examples 1 to 23 , a total of 58 to 96 parts by mass of the resin component (A1) and the resin component (A2) should be contained in 100 parts by mass of the carrier resin (A) of the silane crosslinking catalyst composition. It is preferable that the carrier resin (A) contains 8 to 42 parts by weight of the resin component (A1) and 6 to 42 parts by weight of the mineral oil in 100 parts by weight of the carrier resin (A). Furthermore, the silane crosslinking catalyst composition preferably contains 5 to 400 parts by mass, more preferably 25 to 300 parts by mass, of filler per 100 parts by mass of carrier resin (A).
In addition, the electric wires of Examples 1 to 19 , in which this silane crosslinking catalyst composition was used in combination with a silane graft resin or silane MB in a specific ratio, had excellent appearance (and heat deformation characteristics) even if they were small in diameter. ing. As described above, when the catalyst composition for silane crosslinking of the present invention is used in combination with a silane graft resin in a specific ratio, a silane crosslinked resin having an excellent appearance can be obtained even when the screw rotation speed of the extruder is lowered to about 2 to 6 rpm. Molded objects can be manufactured. Furthermore, the electric wires of Examples 20 to 23 using silane MB, which is obtained by grafting a silane coupling agent premixed with an inorganic filler to a base resin, have a higher level of appearance and heat resistance even though they have a small diameter. It has both.

Claims (7)

A silane crosslinking catalyst composition used for crosslinking a silane grafted resin grafted with a silane coupling agent having a hydrolyzable silyl group, the composition comprising:
A carrier resin (A) containing at least one resin component (A1) selected from a styrenic thermoplastic elastomer or an ethylene-α olefin copolymer rubber, and a mineral oil;
At least one filler (B) selected from halogen flame retardants and inorganic fillers;
a silanol condensation catalyst (C),
Contains
In addition to the resin component (A1), the carrier resin (A) includes at least one resin selected from ethylene-based copolymers including ethylene-α olefin copolymers, ethylene-acrylic rubbers, and high-density polyethylene resins. Contains component (A2),
The content of the mineral oil is 10 to 40% by mass in the carrier resin (A),
Containing 5 to 400 parts by mass of the filler per 100 parts by mass of the carrier resin (A),
The mixing ratio of the silanol condensation catalyst (C) is set to 0.02 to 0.5 parts by mass with respect to a total of 100 parts by mass of the silane graft resin and the carrier resin (A),
A mixing ratio of the carrier resin (A) to the silane graft resin is set to 18 to 35% by mass with respect to a total of 100% by mass of the silane graft resin and the carrier resin (A). Catalyst composition for silane crosslinking. The catalyst composition for silane crosslinking according to claim 1, characterized in that it contains a total of 60 to 90 parts by mass of the resin component (A1) and the resin component (A2) in 100 parts by mass of the carrier resin (A). thing. The silane crosslinking catalyst composition according to claim 1, characterized in that it contains 8 to 42 parts by mass of the resin component (A1) in 100 parts by mass of the carrier resin (A). The silane crosslinking catalyst composition according to any one of claims 1 to 3, characterized in that it contains 25 to 300 parts by mass of the filler based on 100 parts by mass of the carrier resin (A). The silane crosslinking catalyst composition according to any one of claims 1 to 3, comprising 200 to 300 parts by mass of the filler based on 100 parts by mass of the carrier resin (A). A kit for preparing a silane crosslinked resin molded article, comprising a combination of a silane graft resin and the silane crosslinking catalyst composition according to any one of claims 1 to 5 . A step (b) of melt-mixing the silane graft resin and the silane crosslinking catalyst composition according to any one of claims 1 to 5 and then molding the molded body obtained in step (b) with water. A method for producing a silane crosslinked resin molded article, comprising a step (c) of crosslinking by contacting with a silane crosslinked resin molded article.