JP6490618B2 - Flame-retardant crosslinked resin molded body, flame-retardant crosslinked resin composition and production method thereof, flame-retardant silane masterbatch, and flame-retardant molded article - Google Patents

Description

  The present invention relates to a flame retardant crosslinked resin molded article, a flame retardant crosslinked resin composition and a production method thereof, a flame retardant silane masterbatch, and a flame retardant molded article using the flame retardant crosslinked resin molded article. About.

  A wide variety of wiring materials for insulated wires, cables, cords, optical fiber cores, or optical fiber cords used for internal wiring or external wiring of electrical / electronic devices are used depending on applications. For example, a low-smoke-resistant flame-retardant wiring material includes a coating layer containing a metal hydrate that exhibits flame retardancy around a conductor. In particular, aluminum hydroxide is used among metal hydrates for the coating layer of wiring materials used outdoors or wiring materials requiring acid resistance.

In the wiring material as described above, the resin forming the coating layer may be cross-linked in order to improve the characteristics. Examples of the resin crosslinking method include an electron beam crosslinking method and a chemical crosslinking method. Among chemical cross-linking methods, the silane cross-linking method is advantageous in production as compared with other cross-linking methods because no special equipment is required in the cross-linking step.
The silane crosslinking method is a method in which a hydrolyzable silane coupling agent having an unsaturated group is grafted to a resin in the presence of an organic peroxide to obtain a silane graft resin, and then the silane grafting in the presence of a silanol condensation catalyst. This is a method of crosslinking a resin by bringing the resin into contact with moisture.
As an example of applying the silane cross-linking method, for example, in Patent Document 1, an inorganic filler obtained by surface-treating a resin component obtained by mixing a polyolefin resin and a maleic anhydride resin with a silane coupling agent, a silane coupling agent, There has been proposed a method in which an organic peroxide and a crosslinking catalyst are sufficiently melt-kneaded with a kneader and then molded with a single screw extruder.
As another method, for example, in Patent Documents 2 to 4, a thermoplastic resin or elastomer composition containing a hydrogenated block copolymer and a non-aromatic rubber softener or the like was subjected to silane surface treatment. A method of partial crosslinking using an organic peroxide through an inorganic filler has been proposed.

  On the other hand, also in the wiring material provided with the crosslinked resin molded body as a coating layer, flexibility is required depending on the application and usage form. Generally, flexibility can be imparted to the crosslinked resin molded body (coating layer) by using a metal hydrate that has been treated with fatty acid.

JP 2001-101928 A JP 2000-143935 A JP 2000-315424 A JP 2001-240719 A

  In the conventional silane cross-linking methods using aluminum hydroxide, including the methods described in Patent Documents 1 to 4 above, foaming occurs during melt mixing with aluminum hydroxide depending on the manufacturing conditions. The present inventors have found that the appearance is deteriorated and the mechanical strength is lowered. Moreover, when the fatty acid-treated aluminum hydroxide is used as in the above-described method, the appearance is remarkably deteriorated.

The present invention provides a method for producing a flame-retardant crosslinked resin molded article that can produce a flame-retardant crosslinked resin molded article having good appearance, flexibility, and acid resistance, and a flame-retardant crosslinked resin molded article having the above characteristics. The challenge is to provide a body.
Moreover, this invention makes it a subject to provide the flame-retardant silane masterbatch which can form this flame-retardant crosslinked resin molding, a flame-retardant crosslinked resin composition, and its manufacturing method.
Furthermore, this invention makes it a subject to provide the flame-retardant molded article containing the flame-retardant crosslinked resin molded object obtained with the manufacturing method of the flame-retardant crosslinked resin molded object.

  The inventors have a specific composition in a specific silane crosslinking method in which a silane master batch prepared by melt-mixing a resin, an inorganic filler, and a silane coupling agent in a specific mixing mode and a silanol condensation catalyst are mixed. It is possible to produce a flame-retardant crosslinked resin molded article having both good appearance and flexibility, and acid resistance by using a base resin having a silane coupling agent and boehmite as an inorganic filler. I found it. Based on this knowledge, the present inventors have further studied and have come to make the present invention.

That is, the subject of this invention was achieved by the following means.
<1> A method for producing a flame-retardant crosslinked resin molded article, comprising the following step (1), step (2) and step (3),
Step (1): 0.01 to 0.6 parts by mass of organic peroxide, 60 to 200 parts by mass of boehmite, and 100% by mass of the base resin react with the boehmite, thereby silanol condensation.
Possible reaction sites and graphs capable of grafting to the base resin in the presence of radicals
A step of melt-mixing 2 to 15 parts by mass of a silane coupling agent having a phthalating reaction site and a silanol condensation catalyst to obtain a mixture Step (2): Molding the mixture obtained in Step (1) above Step of obtaining molded body Step (3): Step of contacting the molded body obtained in the step (2) with water to obtain a flame retardant crosslinked resin molded body The base resin is at least one of polyolefin resin and ethylene rubber Containing a seed, and containing 100% by mass or less of the polyolefin resin, 100% by mass or less of the ethylene rubber, 35% by mass or less of a styrene-based elastomer, and 40% by mass or less of oil,
In carrying out the step (1), when all of the base resin is melt-mixed in the following step (a-2), the step (1) includes the following step (a-1), step (a-2) and In the case of having a step (c) and melting and mixing a part of the base resin in the following step (a-2), the step (1) is the following step (a-1), step (a-2), The manufacturing method of a flame-retardant crosslinked resin molding which has a process (b) and a process (c).
Step (a-1): Step of preparing a mixture by mixing at least the boehmite and the silane coupling agent Step (a-2): The mixture and the whole or part of the base resin are mixed with the organic peracid. by melt mixing at a decomposition temperature or more of the temperature of the organic peroxide in the presence of a product, prior to
A graft reaction between the grafting reaction site and the base resin
Step of preparing a flame retardant silane master batch containing a run crosslinkable resin Step (b): Melting and mixing the remainder of the base resin and the silanol condensation catalyst,
Step of preparing catalyst master batch Step (c): Step of melting and mixing the flame-retardant silane master batch and the silanol condensation catalyst or the catalyst master batch <2> The base resin is a polyolefin resin of 50% by mass The method for producing a flame-retardant crosslinked resin molded article according to <1>, comprising 10 to 100% by mass of ethylene rubber, 35% by mass or less of styrene elastomer, and 40% by mass or less of oil.
<3> The base resin contains 20 to 40% by mass of a polyolefin resin, 10 to 60% by mass of ethylene rubber, 10 to 35% by mass of a styrenic elastomer, and 10 to 40% by mass of an oil, <1> Or the manufacturing method of the flame-retardant crosslinked resin molding as described in <2>.
<4> The flame-retardant crosslinked resin molded article according to any one of <1> to <3>, wherein a blending amount of the boehmite is 60 to 170 parts by mass with respect to 100 parts by mass of the base resin. Production method.
<5> 0.01 to 0.6 parts by mass of an organic peroxide, 60 to 200 parts by mass of boehmite, and a reactive site capable of silanol condensation by reacting with the boehmite and a radical with respect to 100 parts by mass of the base resin. A flame-retardant crosslinkable resin comprising a step (1) of melt-mixing 2 to 15 parts by mass of a silane coupling agent having a grafting reaction site capable of undergoing a graft reaction with the base resin in the presence of A method for producing a composition comprising:
The base resin contains at least one of a polyolefin resin and ethylene rubber, the polyolefin resin is 100% by mass or less, the ethylene rubber is 100% by mass or less, the styrene elastomer is 35% by mass or less, and an oil At a ratio of 40% by mass or less,
In carrying out the step (1), when all of the base resin is melt-mixed in the following step (a-2), the step (1) includes the following step (a-1), step (a-2) and In the case of having a step (c) and melting and mixing a part of the base resin in the following step (a-2), the step (1) is the following step (a-1), step (a-2), A method for producing a flame-retardant crosslinkable resin composition, comprising steps (b) and (c).
Step (a-1): Step of preparing a mixture by mixing at least the boehmite and the silane coupling agent Step (a-2): The mixture and the whole or part of the base resin are mixed with the organic peracid. by melt mixing at a decomposition temperature or more of the temperature of the organic peroxide in the presence of a product, prior to
A graft reaction between the grafting reaction site and the base resin
Step of preparing a flame retardant silane master batch containing a run crosslinkable resin Step (b): Melting and mixing the remainder of the base resin and the silanol condensation catalyst,
Step of preparing a catalyst master batch Step (c): Step of melt-mixing the flame retardant silane master batch and the silanol condensation catalyst or the catalyst master batch <6> Flame retardancy as described in <5> above A flame-retardant crosslinkable resin composition produced by a method for producing a crosslinkable resin composition.
<7> A flame-retardant crosslinked resin molded article produced by the method for producing a flame-retardant crosslinked resin molded article according to any one of <1> to < 4 >.
<8> A flame-retardant molded article comprising the flame-retardant crosslinked resin molded article according to <7> above.
<9> 0.01 to 0.6 parts by weight of an organic peroxide, 60 to 200 parts by weight of boehmite, and a reactive site capable of silanol condensation by reacting with the boehmite and a radical with respect to 100 parts by weight of the base resin. For producing a flame retardant crosslinkable resin composition obtained by melt-mixing 2 to 15 parts by mass of a silane coupling agent having a grafting reaction site capable of grafting to the base resin in the presence of a silanol condensation catalyst A flame retardant silane masterbatch used,
The base resin contains at least one of a polyolefin resin and ethylene rubber, the polyolefin resin is 100% by mass or less, the ethylene rubber is 100% by mass or less, the styrene elastomer is 35% by mass or less, and an oil At a ratio of 40% by mass or less,
A mixture is prepared by mixing at least the boehmite and the silane coupling agent, and the decomposition temperature of the organic peroxide is obtained by mixing the obtained mixture and all or part of the base resin in the presence of the organic peroxide. A flame-retardant silane masterbatch containing a silane crosslinkable resin, which is obtained by melting and mixing at the above temperature to cause a grafting reaction between the grafting reaction site and the base resin .

  In the present specification, a numerical range expressed using “to” means a range including numerical values described before and after “to” as a lower limit value and an upper limit value.

According to the present invention, it is possible to produce a flame-retardant crosslinked resin molded article that overcomes the problems of conventional methods, has a good appearance, and is excellent in flexibility and acid resistance.
Therefore, according to the present invention, it is possible to provide a flame-retardant crosslinked resin molded article having good appearance, flexibility and acid resistance, and a method for producing the same. Moreover, the flame-retardant silane masterbatch which can form the flame-retardant crosslinked resin molding which has such a characteristic, a flame-retardant crosslinked resin composition, and its manufacturing method can be provided. Furthermore, the flame-retardant molded article containing the above-mentioned flame-retardant crosslinked resin molding can be provided.

In the present invention, a base resin, an organic peroxide, boehmite, a silane coupling agent, and a silanol condensation catalyst are used, and a carrier resin or various additives are used as necessary.
Each component used in the present invention will be described.

<Base resin>
The base resin used in the method for producing a flame-retardant crosslinked resin molded product in the present invention contains at least one of a polyolefin resin and ethylene rubber. In this case, the base resin is a resin mixture containing 100% by mass or less of polyolefin resin, 100% by mass or less of ethylene rubber, 35% by mass or less of styrene elastomer, and 40% by mass or less of oil. .

(Resin component)
As the resin component that can be contained in the base resin, a resin having a site capable of graft reaction in the main chain or at the terminal in the presence of a vinyl group of a silane coupling agent and an organic peroxide is used. Examples of the site capable of graft reaction include a carbon chain unsaturated bond site and a carbon atom having a hydrogen atom.
Examples of such resin components include polyolefin resins, ethylene rubber, and styrene elastomers. In the present invention, the base resin contains at least one of polyolefin resin and ethylene rubber, and preferably contains any two of polyolefin resin, ethylene rubber and styrene elastomer, and contains all of them. More preferably. Among these, it is particularly preferable to contain ethylene rubber as one of the resin components.

− Polyolefin resin −
The polyolefin resin is not particularly limited as long as it is a resin obtained by polymerizing or copolymerizing a compound having an ethylenically unsaturated bond, and conventionally known ones used in flame retardant resin compositions. Can be used. For example, polyethylene, polypropylene, ethylene-α-olefin copolymer, block copolymer of polypropylene and ethylene-α-olefin resin, each resin of polyolefin copolymer having acid copolymerization component or acid ester copolymerization component Can be mentioned. Further, rubbers or elastomers of these copolymers (excluding ethylene rubber and styrenic elastomer) are also included. For example, an acrylic rubber is mentioned.

The polyethylene resin only needs to be a resin having an ethylene component as a main component, a homopolymer composed only of ethylene, a copolymer of ethylene and an α-olefin (preferably 5 mol% or less), and ethylene (preferably Includes a resin of a copolymer with a non-olefin (having only carbon, oxygen and hydrogen atoms in a functional group, and preferably 1 mol% or less) (for example, JIS K 6748). As the α-olefin and the non-olefin described above, known ones conventionally used as a copolymerization component of polyethylene can be used without particular limitation. As an alpha olefin, a C4-C12 thing is preferable and what is mentioned later is mentioned.
Polyethylene resins 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), and very low density polyethylene (VLDPE). ) And the like. Among these, linear low density polyethylene and low density polyethylene are preferable. A polyethylene resin may be used individually by 1 type, and may use 2 or more types together.

  As an acid copolymerization component or an acid ester copolymerization component in a polyolefin copolymer having an acid copolymerization component or an acid ester copolymerization component, each component such as vinyl acetate, (meth) acrylic acid, alkyl (meth) acrylate, etc. Is mentioned. Here, the alkyl group of the alkyl (meth) acrylate component preferably has 1 to 12 carbon atoms, and examples thereof include a methyl group, an ethyl group, a propyl group, a butyl group, and a hexyl group. Examples of polyolefin copolymer resins (excluding those contained in polyethylene resin) having an acid copolymerization component or an acid ester copolymerization component include ethylene-vinyl acetate copolymer (EVA), ethylene- (meth). Examples of the resins include acrylic acid copolymers and ethylene- (meth) acrylic acid alkyl copolymers. Among these, ethylene-vinyl acetate copolymer, ethylene-methyl acrylate copolymer, ethylene-ethyl acrylate copolymer (EEA), and ethylene-butyl acrylate copolymer are preferable, and boehmite From the viewpoint of acceptability, an ethylene-vinyl acetate copolymer resin is preferred. The polyolefin copolymer resin having an acid copolymerization component or an acid ester copolymerization component may be used alone or in combination of two or more.

Polypropylene resin should just be resin which has a propylene component as a main component, and includes random polypropylene and block polypropylene other than the propylene homopolymer.
Here, the random polypropylene is a copolymer of propylene and ethylene and has an ethylene component content of 1 to 5% by mass. The block polypropylene is a composition containing a homopolypropylene and an ethylene-propylene copolymer, the ethylene component content is about 5 to 15% by mass, and the ethylene component and the propylene component are present as independent components. Say.

  The ethylene-α-olefin copolymer is preferably a copolymer of ethylene and an α-olefin having 3 to 12 carbon atoms (except for those contained in the polyethylene and polypropylene).

  The acrylic rubber (ACM) is not particularly limited, but is obtained by copolymerizing an alkyl acrylate such as ethyl acrylate or butyl acrylate and a monomer having an unsaturated hydrocarbon or various functional groups as a constituent component. A rubber elastic body made of a copolymer is preferable. Although it does not specifically limit as a monomer copolymerized with alkyl acrylate, Ethylene, 2-chloroethyl vinyl ether, methyl vinyl ketone, acrylic acid, acrylonitrile, a butadiene etc. can be mentioned.

As polyolefin resin, according to a use or a required characteristic, each above-mentioned resin can be used 1 type or in combination of 2 or more types.
For example, when a high degree of flexibility is required by the flame-retardant crosslinked resin molded article, the base resin is a linear low-density polyethylene having a density of 0.915 g / cm ² or less among the above resins as a polyolefin resin ( LLDPE), very low density polyethylene (VLDPE), and one or more resins selected from the group consisting of ethylene-α-olefin copolymers are preferably included. In particular, when the polypropylene resin is not contained as the polyolefin resin, higher flexibility can be imparted to the flame-retardant crosslinked resin molded product. On the other hand, when high intensity | strength or an abrasion characteristic is calculated | required by a flame-retardant crosslinked resin molding, it is preferable that base resin contains polypropylene resin among each above-mentioned resin. Furthermore, when high flame retardancy is required by the flame-retardant crosslinked resin molded article, the base resin is selected from the group consisting of a polyolefin copolymer having an acid copolymerization component or an acid ester copolymerization component and acrylic rubber. It is preferable that 1 type or 2 or more types of resin is included.

− Ethylene rubber −
The ethylene rubber is not particularly limited as long as it is a rubber (including an elastomer) made of a copolymer obtained by copolymerizing a compound having an ethylenically unsaturated bond, and a known rubber can be used. Preferred examples of the ethylene rubber include a copolymer of ethylene and α-olefin, and a rubber made of a terpolymer of ethylene, α-olefin and diene. The diene of the terpolymer may be a conjugated diene or a non-conjugated diene, and is preferably a non-conjugated diene. That is, examples of the ternary copolymer include a ternary copolymer of ethylene, an α-olefin, and a conjugated diene, and a terpolymer of ethylene, an α-olefin, and a nonconjugated diene. As the ethylene rubber, a copolymer of ethylene and α-olefin and a terpolymer of ethylene, α-olefin and non-conjugated diene are preferable.
As the α-olefin, each α-olefin having 3 to 12 carbon atoms is preferable, and propylene, 1-butene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-decene, 1-dodecene and the like are preferable. Can be mentioned. Examples of the conjugated diene include butadiene, isoprene, 1,3-pentadiene, 2,3-dimethyl-1,3-butadiene, and the like, with butadiene being preferred. Non-conjugated dienes include, for example, dicyclopentadiene (DCPD), ethylidene norbornene (ENB), 1,4-hexadiene, and ethylidene norbornene is preferred.
Examples of rubber made of a copolymer of ethylene and α-olefin include ethylene-propylene rubber, ethylene-butene rubber, and ethylene-octene rubber. Examples of the rubber composed of a terpolymer of ethylene, α-olefin and diene include ethylene-propylene-diene rubber and ethylene-butene-diene rubber. Among these, ethylene-propylene rubber, ethylene-butene rubber, ethylene-propylene-diene rubber and ethylene-butene-diene rubber are preferable, and ethylene-propylene rubber and ethylene-propylene-diene rubber are more preferable.

As for ethylene rubber, the amount of ethylene constituents (referred to as ethylene content) in the copolymer is preferably 45 to 75% by mass, more preferably 50 to 72% by mass, and still more preferably 55 to 70% by mass. When the ethylene content is within this range, both flexibility and tensile strength can be achieved. The ethylene content is a value measured according to the method described in ASTM D3900.
When the content of the ethylene rubber in the base resin is 60 parts by mass or more, the diene constituent amount (referred to as diene content) of the ethylene rubber is preferably 0 to 3.5% by mass, and more preferably 0 to 3% by mass 0 to 2.5% by mass is more preferable. The diene content can be measured by, for example, infrared absorption spectroscopy (FT-IR), proton NMR ( ¹ H-NMR) method or the like.

  An ethylene rubber may be used individually by 1 type, and may use 2 or more types together.

− Styrenic elastomer −
Examples of the styrenic elastomer include block copolymers and random copolymers of conjugated diene compounds and aromatic vinyl compounds, or hydrogenated products thereof. Examples of the aromatic vinyl compound include styrene, p- (t-butyl) styrene, α-methylstyrene, p-methylstyrene, divinylbenzene, 1,1-diphenylstyrene, N, N-diethyl-p-aminoethyl. Styrene, vinyl toluene, p- (t-butyl) styrene, etc. are mentioned. Among these, styrene is preferable as the aromatic vinyl compound. These aromatic vinyl compounds may be used alone or in combination of two or more. Examples of the conjugated diene compound include butadiene, isoprene, 1,3-pentadiene, 2,3-dimethyl-1,3-butadiene and the like. Among these, the conjugated diene compound is preferably butadiene. This conjugated diene compound may be used alone or in combination of two or more. In addition, as a styrene-based elastomer, an elastomer containing an aromatic vinyl compound other than styrene, which does not contain a styrene component, may be used by a similar production method.
Examples of the styrene elastomer include styrene-ethylene-butylene-styrene block copolymer (SEBS), styrene-isoprene-styrene block copolymer (SIS), hydrogenated styrene-butadiene-styrene block copolymer (hydrogenated). SBS), styrene-ethylene-ethylene-propylene-styrene block copolymer (SEEPS), styrene-ethylene-propylene-styrene block copolymer (SEPS), styrene-butadiene rubber (SBR), hydrogenated SIS, hydrogenated styrene -What consists of butadiene rubber (HSBR) etc. can be mentioned.
Styrenic elastomers may be used alone or in combination of two or more.

(oil)
The oil that can be contained in the base resin is not particularly limited, and examples thereof include organic oils and mineral oils. When the base resin contains an organic oil, it is possible to produce a flame-retardant crosslinked resin molded article having an excellent appearance by suppressing the occurrence of bumps (tubular protrusions protruding on the surface).
Examples of the organic oil or mineral oil include soybean oil, paraffin oil, naphthenic oil, and aroma oil. Paraffin oil or naphthenic oil is preferable, and paraffin oil is more preferable in terms of mechanical strength.

The base resin has a content of each component in the base resin of 100% by mass, a polyolefin resin in a range of 50% by mass or less, an ethylene rubber in a range of 10 to 100% by mass, and a styrene elastomer in a range of 35%. It is preferable to contain oil in a range of 40% by mass or less, in a range of 20% by mass or less, a polyolefin resin in a range of 20 to 40% by mass, an ethylene rubber in a range of 10 to 60% by mass, and a styrene elastomer. More preferably, the oil is contained in the range of 10 to 35% by mass and the oil in the range of 10 to 40% by mass.
By making the composition of the base resin as described above, both flexibility and strength can be achieved.

  The base resin may contain other components such as various additives and solvents described later.

<Organic peroxide>
The organic peroxide generates radicals by at least thermal decomposition, and serves as a catalyst to cause a graft reaction by radical reaction to the resin component of the silane coupling agent. In particular, when the reaction site of the silane coupling agent contains, for example, an ethylenically unsaturated group, a graft reaction is caused by a radical reaction between the ethylenically unsaturated group and the resin component (including a hydrogen radical abstraction reaction from the resin component). Work.
The organic peroxide is not particularly limited as long as it generates radicals. For example, the general formula: R ¹ —OO—R ² , R ³ —OO—C (═O) R ⁴ , R ⁵ C A compound represented by (═O) —OO (C═O) R ⁶ is preferred. Here, R ^{1 to} R ⁶ each independently represents an alkyl group, an aryl group, or an acyl group. Among R ^{1 to} R ⁶ of each compound, those in which all are alkyl groups or those in which any one is an alkyl group and the remainder is an acyl group are preferable.

  Examples of such organic peroxides include dicumyl peroxide (DCP), di-tert-butyl peroxide, 2,5-dimethyl-2,5-di (tert-butylperoxy) hexane, 2, 5-dimethyl-2,5-di (tert-butylperoxy) hexyne-3, 1,3-bis (tert-butylperoxyisopropyl) benzene, 1,1-bis (tert-butylperoxy) -3, 3,5-trimethylcyclohexane, n-butyl-4,4-bis (tert-butylperoxy) valerate, benzoyl peroxide, p-chlorobenzoyl peroxide, 2,4-dichlorobenzoyl peroxide, tert-butylperoxy Benzoate, tert-butyl peroxyisopropyl carbonate, diaceti Peroxide, lauroyl peroxide, may be mentioned tert- butyl cumyl peroxide and the like. Of these, dicumyl peroxide, 2,5-dimethyl-2,5-di (tert-butylperoxy) hexane, 2,5-dimethyl-2, in terms of odor, colorability, and scorch stability. 5-di (tert-butylperoxy) hexyne-3 is preferred.

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

<Boehmite>
Boehmite means aluminum oxide hydrate (Al ₂ O ₃ .H ₂ O). Boehmite has, on its surface, a site (for example, an oxygen atom) that can be chemically bonded to the reaction site of the silane coupling agent by hydrogen bonding or covalent bonding, or by intermolecular bonding.
In the present invention, boehmite holds a silane coupling agent and acts as a filler or a flame retardant.
In the present invention, boehmite is preferably used without surface treatment.
The average primary particle size of boehmite is not particularly limited, but is preferably 0.3 to 5 μm, and more preferably 0.4 to 2 μm. When the average primary particle size is 0.3 to 5 μm, flame retardancy can be imparted without impairing elongation and strength. Further, boehmite is less likely to agglomerate when mixed with the silane coupling agent, and the appearance is excellent. The average primary particle size is obtained by dispersing boehmite with alcohol or water and using an optical particle size measuring device such as a laser diffraction / scattering particle size distribution measuring device.
The shape of the boehmite is not particularly limited, and a granular shape, a plate shape, a needle shape or the like can be used, and a plate shape is preferable. When it is plate-like, the aspect ratio is preferably 1 to 60, and preferably 1 to 3 from the viewpoint of balance between strength and flexibility.
The BET specific surface area of boehmite is not particularly limited, but is preferably 0.8 to 30 m ² / g and more preferably 1.2 to 25 m ² / g in terms of tensile strength or flexibility. The BET specific surface area is a value measured using nitrogen gas as an adsorbate according to the “carrier gas method” of JIS Z 8830: 2013. For example, it is a value measured using a specific surface area / pore distribution measuring apparatus “Flowsorb” (manufactured by Shimadzu Corporation).

<Silane coupling agent>
The silane coupling agent used in the present invention includes a grafting reaction site (group or atom) capable of grafting to a resin component in the presence of radicals generated by the decomposition of an organic peroxide and a site capable of chemically bonding boehmite. And a reaction site capable of silanol condensation (including a site generated by hydrolysis, such as a silyl ester group). As such a silane coupling agent, the silane coupling agent conventionally used for the silane crosslinking method is mentioned.

  As such a silane coupling agent, for example, a compound represented by the following general formula (1) can be used.

In general formula (1), R _a11 is a group containing an ethylenically unsaturated group, and R _b11 is an aliphatic hydrocarbon group, a hydrogen atom, or Y ¹³ . Y ¹¹ , Y ¹² and Y ¹³ are hydrolyzable organic groups. Y ¹¹ , Y ¹² and Y ¹³ may be the same as or different from each other.

R _a11 is a grafting reaction site and is preferably a group containing an ethylenically unsaturated group. Examples of the group containing an ethylenically unsaturated group include a vinyl group, a (meth) acryloyloxyalkylene group, and a p-styryl group. Among these, a vinyl group is preferable.

Examples of the aliphatic hydrocarbon group that can be taken by R _b11 include _C 1-8 monovalent aliphatic hydrocarbon groups excluding an aliphatic unsaturated hydrocarbon group. R _b11 is preferably Y ¹³ described later.

Y ¹¹ , Y ¹² and Y ¹³ are silanol-condensable reaction sites (hydrolyzable organic groups), for example, an alkoxy group having 1 to 6 carbon atoms, an aryloxy group having 6 to 10 carbon atoms, and a carbon number The acyloxy group of 1-4 is mentioned, An alkoxy group is preferable. Specific examples of the hydrolyzable organic group include methoxy, ethoxy, butoxy, acyloxy and the like. Among these, methoxy or ethoxy is more preferable, and methoxy is particularly preferable from the viewpoint of the reactivity of the silane coupling agent.

The silane coupling agent is preferably a silane coupling agent having a high hydrolysis rate, more preferably a silane cup in which R _b11 is Y ¹³ and Y ¹¹ , Y ¹² and Y ¹³ are the same. A ring agent or a hydrolyzable silane coupling agent in which at least one of Y ¹¹ , Y ¹² and Y ¹³ is a methoxy group.

Specific examples of the silane coupling agent include vinyltrimethoxysilane, vinyltriethoxysilane, vinyltributoxysilane, vinyldimethoxyethoxysilane, vinyldimethoxybutoxysilane, vinyldiethoxybutoxysilane, allyltrimethoxysilane, allyltrimethoxysilane. Examples thereof include vinyl silanes such as ethoxysilane and vinyltriacetoxysilane, and (meth) acryloxysilanes such as methacryloxypropyltrimethoxysilane, methacryloxypropyltriethoxysilane, and methacryloxypropylmethyldimethoxysilane.
Among the silane coupling agents, a silane coupling agent having a vinyl group and an alkoxy group at the terminal is more preferable, and vinyltrimethoxysilane and vinyltriethoxysilane are particularly preferable.

  A silane coupling agent may be used individually by 1 type, and may use 2 or more types together. Further, it may be used as it is or diluted with a solvent or the like.

<Silanol condensation catalyst>
The silanol condensation catalyst functions to cause a condensation reaction of the silane coupling agent grafted to the resin component in the presence of moisture. Based on the action of this silanol condensation catalyst, the resin components are cross-linked through a silane coupling agent. As a result, a flame-retardant crosslinked resin molded product having the above-described excellent characteristics is obtained.

  Examples of the silanol condensation catalyst used in the present invention include organotin compounds, metal soaps, platinum compounds and the like. Common silanol condensation catalysts include, for example, dibutyltin dilaurate, dioctyltin dilaurate, dibutyltin dioctate, dibutyltin diacetate, zinc stearate, lead stearate, barium stearate, calcium stearate, sodium stearate, lead naphthenate, Lead sulfate, zinc sulfate, organic platinum compounds and the like are used. Among these, organic tin compounds such as dibutyltin dilaurate, dioctyltin dilaurate, dibutyltin dioctate, and dibutyltin diacetate are particularly preferable.

<Carrier resin>
The silanol condensation catalyst is used by mixing with a resin or rubber as desired. Such a resin or rubber (also referred to as carrier resin) is not particularly limited, and the resin component described in the base resin can be used. The carrier resin is preferably ethylene rubber.

<Additives>
The flame retardant crosslinked resin molded body and the flame retardant crosslinked resin composition include various wiring materials such as electric wires, electric cables, and electric cords, sheets, foams, tubes, and pipes that are generally used. You may contain an additive in the range which does not impair the effect of this invention. Examples of such additives include crosslinking aids, antioxidants, lubricants, metal deactivators, and fillers (including flame retardant (auxiliary) agents) other than the boehmite.

Although it does not specifically limit as antioxidant, For example, amine antioxidant, phenol antioxidant, sulfur antioxidant, etc. are mentioned. Examples of the amine antioxidant include a polymer of 4,4′-dioctyldiphenylamine, N, N′-diphenyl-p-phenylenediamine, 2,2,4-trimethyl-1,2-dihydroquinoline, and the like. . Examples of the phenol antioxidant include pentaerythritol-tetrakis (3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate), octadecyl-3- (3,5-di-tert-butyl- 4-hydroxyphenyl) propionate, 1,3,5-trimethyl-2,4,6-tris (3,5-di-tert-butyl-4-hydroxybenzyl) benzene and the like. Examples of the sulfur antioxidant include bis (2-methyl-4- (3-n-alkylthiopropionyloxy) -5-tert-butylphenyl) sulfide, 2-mercaptobenzimidazole and its zinc salt, pentaerythritol-tetrakis. (3-lauryl-thiopropionate) and the like.
The antioxidant can be added in an amount of preferably 0.1 to 15.0 parts by mass, more preferably 0.1 to 10 parts by mass with respect to 100 parts by mass of the base resin.

Next, the production method of the present invention will be specifically described.
Both the method for producing a flame-retardant crosslinked resin molded product of the present invention and the method for producing a flame-retardant crosslinked resin composition of the present invention perform at least the following step (1). Therefore, the method for producing the flame-retardant crosslinked resin molded product of the present invention and the method for producing the flame-retardant crosslinked resin composition of the present invention will be described together below (in the description common to both production methods, the present invention May be referred to as a manufacturing method.)
The flame-retardant crosslinked resin molded product of the present invention is a molded product obtained by this production method.
Moreover, the flame-retardant silane masterbatch of this invention is manufactured by the following process (a-1) and process (a-2) (both processes are collectively called process (a)). Therefore, the manufacturing method of the flame-retardant silane masterbatch of this invention is demonstrated in the manufacturing method of this invention.

The method for producing a flame-retardant crosslinked resin molded article of the present invention includes the following steps (1) to (3).
Step (1): 0.01 to 0.6 parts by mass of an organic peroxide, 60 to 200 parts by mass of boehmite, 2 to 15 parts by mass of a silane coupling agent with respect to 100 parts by mass of the base resin,
Step of obtaining a mixture by melt-mixing with a silanol condensation catalyst Step (2): Step of obtaining a molded body by molding the mixture obtained in Step (1) Step (3): Obtained in Step (2) Of obtaining a flame-retardant crosslinked resin molded product by bringing the molded product into contact with water

And when this process (1) melt-mixes all of base resin at the following process (a-2), it has a process (a-1), a process (a-2), and a process (c) at least. When a part of the base resin is melt-mixed in the following step (a-2), at least the following step (a-1), step (a-2), step (b) and step (c) are included.
Step (a-1): Step of preparing a mixture by mixing at least the boehmite and the silane coupling agent Step (a-2): The mixture and the whole or part of the base resin are mixed with the organic peracid. Step of preparing a flame retardant silane masterbatch by melting and mixing at a temperature equal to or higher than the decomposition temperature of the organic peroxide in the presence of a chemical compound Step (b): Melting and mixing the remainder of the base resin and the silanol condensation catalyst do it,
Step of preparing a catalyst master batch Step (c): Step of melt-mixing the flame retardant silane master batch and the silanol condensation catalyst or the catalyst master batch. Here, mixing means obtaining a uniform mixture. Say.

  In the production method of the present invention, the base resin is a resin for forming a flame retardant crosslinked resin molded product or a flame retardant crosslinked resin composition. Therefore, in the production method of the present invention, 100 parts by mass of the base resin may be contained in the mixture obtained in step (1). For example, in the step (a-2), an aspect in which the total amount (100 parts by mass) of the base resin is blended and an aspect in which a part of the base resin is blended are included.

When a part of the base resin is blended in the step (a-2), the blending amount of 100 parts by mass of the base resin in the step (1) is that of the base resin mixed in the step (a-2) and the step (b). Total amount.
Here, when the remainder of the base resin is blended in the step (b), the base resin is blended in the step (a-2), preferably 80 to 99% by mass, more preferably 94 to 98% by mass, In a process (b), Preferably 1-20 mass%, More preferably, 2-6 mass% is mix | blended.

In step (1), the composition of the base resin is as described above.
That is, the base resin contains at least one of a polyolefin resin and ethylene rubber, the polyolefin resin is in the range of 0 to 100% by mass, the ethylene rubber is in the range of 0 to 100% by mass, and the styrene elastomer is 0 to 35%. The range of mass% and the oil are selected and used from the range of 0 to 40 mass% so that the total is 100 mass%.

  In the step (1), the compounding amount of the organic peroxide is 0.01 to 0.6 parts by mass, preferably 0.1 to 0.5 parts by mass with respect to 100 parts by mass of the base resin. When the amount of the organic peroxide is less than 0.01 parts by mass, the grafting reaction does not proceed, and the unreacted silane coupling agents are condensed with each other to provide sufficient mechanical properties or heat resistance, and in some cases sufficient reinforcement. You may not be able to get to. On the other hand, when it exceeds 0.6 parts by mass, many of the resin components are directly cross-linked by a side reaction to form a chip and a poor appearance may occur. That is, by setting the blending amount of the organic peroxide within this range, a graft reaction can be performed within an appropriate range, and a composition excellent in extrudability without generating gel-like lumps (agglomerates). Can be obtained.

  The compounding quantity of boehmite is 60-200 mass parts with respect to 100 mass parts of base resins, Preferably it is 60-170 mass parts. When the blending amount of boehmite is less than 60 parts by mass, the flame retardancy of the obtained flame retardant crosslinked resin molded product may be inferior. In addition, the graft reaction of the silane coupling agent may become non-uniform. Thereby, an external appearance falls and heat resistance may fall further. On the other hand, when it exceeds 200 parts by mass, the obtained flame-retardant crosslinked resin molded product may be inferior in flexibility. Moreover, the load at the time of shaping | molding and kneading | mixing becomes very large, and secondary shaping | molding may become difficult.

The compounding quantity of a silane coupling agent is 2-15 mass parts with respect to 100 mass parts of base resins. When the blending amount of the silane coupling agent is less than 2 parts by mass, the crosslinking reaction does not proceed sufficiently, and mechanical properties or heat resistance may not be obtained. On the other hand, when the amount exceeds 15 parts by mass, excessive silane coupling agent cannot be adsorbed on the surface of boehmite, and the silane coupling agent may condense, causing the molded product to be fuzzy or burnt, resulting in deterioration in appearance. It is not economical.
From the said viewpoint, the compounding quantity of a silane coupling agent becomes like this. Preferably it is 3-12 mass parts with respect to 100 mass parts of base resins, More preferably, it is 4-12 mass parts.

  The compounding amount of the silanol condensation catalyst is not particularly limited, and is preferably 0.0001 to 0.5 parts by mass, more preferably 0.001 to 0.1 parts by mass with respect to 100 parts by mass of the base resin. When the amount of the silanol condensation catalyst is within the above range, the crosslinking reaction due to the condensation reaction of the silane coupling agent is likely to proceed almost uniformly, and the heat resistance, appearance and physical properties of the flame-retardant crosslinked resin molded product are excellent, and production Also improves. That is, if the amount of the silanol condensation catalyst is too small, the mechanical strength and, in some cases, sufficient heat resistance may not be obtained. On the other hand, if the amount is too large, the crosslinking reaction due to the condensation reaction of the silane coupling agent becomes uneven, and the appearance and productivity may be inferior.

In the production method of the present invention, step (1) is performed.
In this step (1), all or part of the base resin, organic peroxide, boehmite, silane coupling agent, and silanol condensation catalyst are melt-mixed in a specific mixing order.

  In the present invention, first, at least boehmite and a silane coupling agent are mixed to prepare a mixture (step (a-1)). That is, the silane coupling agent is premixed with an inorganic filler. The silane coupling agent premixed in this manner exists so as to surround the surface of boehmite, and part or all of the silane coupling agent is adsorbed or bonded to boehmite. Thereby, volatilization of the silane coupling agent can be reduced during subsequent melt mixing. Moreover, it is possible to prevent the silane coupling agent from condensing and becoming difficult to melt and mix. Furthermore, a desired shape can be obtained during extrusion molding.

As such a mixing method, preferably at least boehmite and a silane coupling agent are used for several minutes to several hours at an arbitrary temperature, for example, a temperature lower than the decomposition temperature of the organic peroxide, preferably room temperature (25 ° C.). There is a method in which after mixing (dispersing) in a dry or wet manner, this mixture, a base resin and an organic peroxide are melt-mixed. This mixing is preferably performed with a mixer-type kneader such as a Banbury mixer or a kneader. If it does in this way, the excessive crosslinking reaction of resin components can be prevented, and the external appearance will be excellent.
In the mixing method of boehmite and the silane coupling agent, a base resin may be present, and when an organic peroxide coexists, a temperature lower than the decomposition temperature is maintained. In this case, it is preferable that the boehmite and the silane coupling agent are mixed with the base resin at the above temperature (step (a-1)) and then melt mixed.

As a mixing method of the boehmite and the silane coupling agent, a wet process or a dry process is exemplified. Specifically, a wet process in which a silane coupling agent is added in a state where boehmite is dispersed in a solvent such as alcohol or water, a dry process in which both are added by heating or non-heating, and both are mentioned. In the present invention, dry treatment is preferred in which a silane coupling agent is added to and mixed with boehmite, preferably dried boehmite.
In wet mixing, since the cohesion between the silane coupling agent and boehmite becomes strong, volatilization of the silane coupling agent can be effectively suppressed, but the silanol condensation reaction may be difficult to proceed. On the other hand, in dry mixing, the silane coupling agent is more volatile than in the case of wet mixing, but since the bonding strength between boehmite and the silane coupling agent is relatively weak, the silanol condensation reaction easily proceeds efficiently. Thereby, a softness | flexibility can be provided to a flame-retardant crosslinked resin molding.

The method of mixing the organic peroxide is not particularly limited, and may be mixed simultaneously with boehmite or the like, or may be mixed in the mixing stage of boehmite and the silane coupling agent.
For example, the organic peroxide may be mixed with boehmite after being mixed with the silane coupling agent, or may be separately mixed with boehmite separately from the silane coupling agent. When mixing an organic peroxide with a silane coupling agent, it is better to mix the organic peroxide and the silane coupling agent substantially together. On the other hand, depending on production conditions, only the silane coupling agent may be mixed with boehmite and then the organic peroxide may be mixed.
The organic peroxide may be mixed with other components or may be a simple substance.

  Next, in the production method of the present invention, all or a part of the obtained mixture and the base resin, and the remaining components not mixed in step (a-1) are organically added in the presence of an organic peroxide. While being heated to a temperature equal to or higher than the decomposition temperature of the peroxide, melt mixing is performed (step (a-2)).

In step (a-2), the temperature at which the above components are melt-mixed (also referred to as melt kneading or kneading) (also referred to as mixing temperature) is equal to or higher than the decomposition temperature of the organic peroxide, preferably the decomposition temperature of the organic peroxide. The temperature is + (25 to 110) ° C. This mixing temperature is preferably set after the resin component has melted. If it is the said mixing temperature, the said component will melt | dissolve and an organic peroxide will decompose | disassemble and act and a required graft reaction will advance. Other conditions such as the mixing time can be set as appropriate.
The mixing method 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 according to, for example, the boehmite content. As the kneading apparatus, a single screw extruder, a twin screw extruder, a roll, a Banbury mixer, various kneaders, or the like is used. A closed mixer such as a Banbury mixer or various kneaders is preferable in terms of the dispersibility of the resin component and the stability of the crosslinking reaction.
In general, when boehmite is mixed in an amount exceeding 100 parts by mass with respect to 100 parts by mass of the base resin, it is preferably kneaded with a continuous kneader, a pressure kneader, or a Banbury mixer.
The method for mixing the base resin is not particularly limited. For example, the base resin may be prepared and used in advance, or each component may be used separately.

  In the step (a-1) and the step (a-2), particularly in the step (a-2), it is preferable to knead the above-mentioned components without substantially mixing the silanol condensation catalyst. Thereby, the condensation reaction of a silane coupling agent can be suppressed, it is easy to melt and mix, and a desired shape can be obtained during extrusion molding. Here, the fact that the silanol condensation catalyst is not substantially mixed does not exclude the unavoidable existing silanol condensation catalyst, and is present to such an extent that the above-mentioned problems due to silanol condensation of the silane coupling agent do not occur. It means that it may be. For example, in the step (a-2), the silanol condensation catalyst may be present as long as it is 0.01 part by mass or less with respect to 100 parts by mass of the base resin.

In step (1), the blending amount of other resins that can be used in addition to the above components and the above additives is appropriately set within a range that does not impair the object of the present invention. In the step (1), the additives, particularly the antioxidant and the metal deactivator may be mixed in any step and may be mixed in any component, but are mixed in the carrier resin. Is good.
In the step (1), particularly in the step (a-1) and the step (a-2), it is preferable that the crosslinking assistant is not substantially mixed. If the crosslinking aid is not substantially mixed, crosslinking between the resin components is difficult to occur during melt mixing, and the appearance of the flame-retardant crosslinked resin molded article and further heat resistance are excellent.

  Thus, a process (a-1) and a process (a-2) are performed and a flame-retardant silane masterbatch (it is also mentioned silane MB) is prepared. As will be described later, this silane MB is preferably used together with a silanol condensation catalyst or a catalyst master batch described later in the production of the mixture (flame retardant crosslinkable resin composition) prepared in step (1). Silane MB contains a silane crosslinkable resin (silane graft polymer) in which a silane coupling agent is grafted to a resin component to such an extent that it can be molded by the step (2) described later.

  Next, in the production method of the present invention, when a part of the base resin is melt-mixed in the step (a-2), the remainder of the base resin and the silanol condensation catalyst are melt-mixed to obtain a catalyst master batch (catalyst MB). (B) is also performed. Therefore, when all the base resin is melt-mixed in the step (a-2), the step (b) may not be performed, and another resin and a silanol condensation catalyst may be mixed.

The mixing ratio of the base resin as the carrier resin and the silanol condensation catalyst is not particularly limited, but is preferably set so as to satisfy the above blending amount in the step (1).
The mixing may be a method capable of uniformly mixing, and includes mixing (melting mixing) performed under melting of the base resin. The melt mixing can be performed in the same manner as the melt mixing in the step (a-2). For example, the mixing temperature can be 80 to 250 ° C, more preferably 100 to 240 ° C. Other conditions such as the mixing time can be set as appropriate.

In the step (b), another resin can be used as the carrier resin in place of or in addition to the remainder of the base resin.
When the carrier resin is another resin, the graft reaction can be promoted in the step (a-2), and it is difficult for the carrier resin to form during molding. The blending amount of the other resin is preferably 1 to 60 parts by mass, more preferably 2 to 50 parts by mass, and further preferably 2 to 40 parts by mass with respect to 100 parts by mass of the base resin.

  In step (b), boehmite may be used. In this case, although the compounding quantity of boehmite is not specifically limited, 350 mass parts or less are preferable with respect to 100 mass parts of carrier resins. This is because when the amount of boehmite is large, the silanol condensation catalyst is difficult to disperse and crosslinking is difficult to proceed.

The catalyst MB prepared in this way is a mixture of a silanol condensation catalyst and a carrier resin, boehmite added if desired.
This catalyst MB is used as a master batch set in the production of the flame-retardant crosslinkable resin composition prepared in step (1) together with silane MB.

In the production method of the present invention, the step (c) is then performed in which the silane MB and the silanol condensation catalyst or catalyst MB are mixed to obtain a mixture.
The mixing method may be any mixing method as long as a uniform mixture can be obtained as described above.

  The mixing in the step (c) is basically the same as the melt mixing in the step (a-2). Some resin components, such as elastomers, whose melting points cannot be measured by DSC or the like, are kneaded at a temperature at which at least one of the resin components is melted. The melting temperature is appropriately selected according to the melting temperature of the base resin or the carrier resin, and is preferably 80 to 250 ° C., more preferably 100 to 240 ° C., for example. Other conditions such as the mixing time can be set as appropriate.

  In the step (c), in order to avoid silanol condensation reaction, it is preferable that the silane MB and the silanol condensation catalyst are not mixed and kept at a high temperature for a long time.

  This step (c) may be any step in which a flame retardant silane master batch and a silanol condensation catalyst are mixed to obtain a mixture, and a catalyst master batch and a flame retardant silane master batch containing a silanol condensation catalyst and a carrier resin. Are melt-mixed.

In this way, the steps (a) to (c) (step (1)), that is, the method for producing the flame retardant crosslinkable resin composition of the present invention is performed, and the flame retardant crosslinkable resin of the present invention is used as a mixture. A composition is produced. This flame-retardant crosslinkable resin composition contains silane crosslinkable resins having different crosslinking methods. In this silane crosslinkable resin, the reactive site of the silane coupling agent may be bonded or adsorbed to boehmite, but is not silanol condensed as described later. Accordingly, the silane crosslinkable resin includes a crosslinkable resin in which a silane coupling agent bonded or adsorbed to boehmite is grafted to the base resin, and a crosslinkable resin in which a silane coupling agent not bonded or adsorbed to boehmite is grafted to the base resin. And at least. The silane crosslinkable resin may be grafted with a silane coupling agent to which boehmite is bonded or adsorbed and a silane coupling agent to which boehmite is not bonded or adsorbed. Furthermore, a silane coupling agent and an unreacted resin component may be included.
As described above, the silane crosslinkable resin is an uncrosslinked product in which the silane coupling agent is not silanol condensed. In practice, when melt-mixed in step (c), partial cross-linking (partial cross-linking) is inevitable, but the obtained flame-retardant cross-linkable resin composition is at least in the molding in step (2). Assume that moldability is maintained.

Next, in the method for producing a flame-retardant crosslinked resin molded article of the present invention, step (2) and step (3) are performed.
In the method for producing a flame-retardant crosslinked resin molded product of the present invention, a step (2) of molding the obtained mixture to obtain a molded product is performed. This process (2) should just be able to shape | mold a mixture, and according to the form of the flame-retardant molded article of this invention, a shaping | molding method and shaping | molding conditions are selected suitably. 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 preferred when the flame retardant molded product of the present invention is an electric wire or an optical fiber cable.

  Moreover, a process (2) can be performed simultaneously with a process (c) or continuously. That is, as one embodiment of the melt mixing in the step (c), there is an embodiment in which the forming raw material is melt-mixed at the time of melt-molding, for example, at the time of extrusion molding or immediately before. For example, pellets such as dry blends may be mixed together at room temperature or high temperature and introduced into a molding machine (melt mixing), or mixed and then melt mixed, pelletized again, and then introduced into the molding machine. Also good. More specifically, a mixture (molding raw material) of silane MB and silanol condensation catalyst or catalyst MB is melt-mixed in a coating apparatus, and then extrusion coated on the outer peripheral surface of a conductor or the like to be molded into a desired shape. A series of processes can be adopted.

In the present invention, molding conditions are not particularly limited, and conventionally employed conditions can be employed.
In this way, a molded body of the flame retardant crosslinkable resin composition is obtained. Similar to the flame-retardant crosslinkable resin composition, this molded body is partially crosslinked, but is in a partially crosslinked state that retains the moldability that can be molded in the step (2). Therefore, the flame-retardant crosslinked resin molded product of the present invention is a molded product that is crosslinked or finally crosslinked by performing the step (3).

In the method for producing a flame-retardant crosslinked resin molded product of the present invention, the step (3) of bringing the molded product obtained in the step (2) into contact with water is performed. Thereby, the reaction site of the silane coupling agent is hydrolyzed to become silanol, and the hydroxyl groups of silanol are condensed with each other by the silanol condensation catalyst present in the molded article, thereby causing a crosslinking reaction. In this way, a flame-retardant crosslinked resin molded product in which the silane coupling agent is crosslinked by silanol condensation can be obtained.
The process itself in this step (3) can be performed by a normal method. Condensation between silane coupling agents proceeds only by storage at room temperature in the presence of moisture. Therefore, in the step (3), it is not necessary to positively contact the molded body with water.
In order to promote this cross-linking reaction, the molded body can be positively brought into contact with moisture. For example, immersion in room temperature water, storage in a high humidity environment, and the like can be mentioned. Furthermore, in order to advance the condensation reaction promptly, if necessary, contact with water positively, such as immersion in warm water (for example, 50 to 90 ° C.), injection into a wet heat tank, exposure to high-temperature steam, etc. Can be adopted. In this case, pressure may be applied to allow moisture to penetrate inside.

  Thus, the manufacturing method of the flame-retardant crosslinked resin molding of this invention is implemented, and a flame-retardant crosslinked resin molding is manufactured from the flame-retardant crosslinked resin composition of this invention. This flame-retardant crosslinked resin molded product contains a crosslinked resin obtained by condensing a silane crosslinkable resin via a siloxane bond. One form of this flame-retardant crosslinked resin molded article contains a silane crosslinked resin and boehmite. Here, boehmite may be bonded to a silane coupling agent of a silane cross-linked resin. Therefore, the silane cross-linked resin includes a cross-linked resin in which a plurality of cross-linked resins are bonded or adsorbed to boehmite by a silane coupling agent and bonded (cross-linked) via boehmite and the silane coupling agent, and the silane of the cross-linkable resin. The reaction site of the coupling agent hydrolyzes and undergoes silanol condensation reaction with each other, thereby containing at least a crosslinked resin crosslinked via a silane coupling agent. Moreover, as for the silane cross-linking resin, a bond (cross-linking) via boehmite and a silane coupling agent and a cross-linking via a silane coupling agent may be mixed. Furthermore, the silane coupling agent and the unreacted resin component and / or the silane crosslinkable resin which is not bridge | crosslinked may be included.

  The details of the reaction mechanism in the production method of the present invention are not yet clear, but are considered as follows. That is, when the resin component is heated and kneaded at a temperature equal to or higher than the decomposition temperature of the organic peroxide together with boehmite and the silane coupling agent in the presence of the organic peroxide, the organic peroxide is decomposed to generate radicals, On the other hand, a graft reaction of the silane coupling agent occurs.

Due to the heating in the step (a-2), a chemical bond forming reaction is caused in part by a covalent bond between a silane coupling agent and a site capable of chemical bonding such as a hydroxyl group on the surface of boehmite.
In the present invention, in step (c), a final cross-linking reaction may be performed. When a specific amount of the silane coupling agent is blended with the base resin as described above, boehmite is added without impairing the extrusion processability during molding. A large amount can be blended, and while maintaining excellent flame retardancy, it can have both mechanical properties and heat resistance.

  Moreover, although the mechanism of the operation of the above process of the present invention is not yet clear, it is estimated as follows. That is, by using boehmite and a silane coupling agent before and / or during kneading with the base resin, the silane coupling agent is bonded to and maintained by boehmite with a group capable of chemically bonding. Alternatively, it is physically and chemically adsorbed and held in the boehmite hole or surface without being bonded to boehmite. In this way, a silane coupling agent that binds to boehmite with a strong bond (for example, the formation of a chemical bond with a hydroxyl group on the surface of boehmite) and a silane coupling agent that binds with a weak bond (the reason) Can form, for example, interactions by hydrogen bonds, interactions between ions, partial charges or dipoles, and actions by adsorption). In this state, when the organic peroxide is added and kneaded, the silane coupling agent is hardly volatilized as described later, and the silane coupling agent having a different bond with boehmite is graft-reacted on the resin component. A crosslinkable resin is formed.

By the above kneading, the silane coupling agent having a strong bond with boehmite among the silane coupling agents is maintained in the bond with boehmite, and the crosslinkable group capable of undergoing a graft reaction is a cross-linked site of the resin component. Graft reaction. In particular, when a plurality of silane coupling agents are bonded to the surface of one boehmite particle through a strong bond, a plurality of resin components are bonded through the boehmite particle. These reactions or bonds expand the cross-linking network through this boehmite. That is, a silane crosslinkable resin formed by graft reaction of the silane coupling agent bonded to boehmite to the resin component is formed.
A silane coupling agent having a strong bond with boehmite hardly causes a condensation reaction in the presence of water by this silanol condensation catalyst, and the bond with boehmite is retained. The binding energy of boehmite and the silane coupling agent is high, and it is considered that the condensation reaction does not occur even under the silanol condensation catalyst. Thus, the resin component and boehmite are bonded, and the resin component is cross-linked via the silane coupling agent. As a result, the adhesiveness between the resin component and boehmite is strengthened, a mechanical strength is high, and a molded body having abrasion resistance and scratch resistance is obtained. In particular, a plurality of silane coupling agents can be bonded to the surface of one boehmite particle, and high mechanical strength can be obtained. Thus, the silane coupling agent bonded to boehmite with a strong bond is considered to contribute to high mechanical properties, and in some cases, wear resistance, scratch resistance, and the like.

  On the other hand, the silane coupling agent having a weak bond with boehmite out of the silane coupling agent is detached from the surface of boehmite and grafts to the resin component. As a result, a silane crosslinkable resin is formed in which a silane coupling agent free from a reactive site capable of silanol condensation is grafted to the resin component. This silane coupling agent is then brought into contact with moisture by a silanol condensation catalyst to cause a condensation reaction (crosslinking reaction). The flame-retardant crosslinked resin molded product obtained by this crosslinking reaction has high flexibility and further improved heat resistance. Thus, it is considered that the silane coupling agent bonded to boehmite with a weak bond contributes to the expression of flexibility by cross-linking without boehmite and further to the improvement of the degree of cross-linking (heat resistance).

In the present invention, when boehmite is used as the inorganic filler, the silane coupling agent tends to be weakly bonded to boehmite. Therefore, the abundance ratio of the silane coupling agent that binds weakly with boehmite and the silane coupling agent that binds strongly with boehmite varies as compared to when a metal hydrate other than boehmite is used as the inorganic filler. Thereby, sufficient flexibility is expressed.
Moreover, as described above, the volatilization of the silane coupling agent and the cross-linking reaction between the base resin or the silane coupling agents can also be suppressed. Furthermore, boehmite exists stably during the above-described melt mixing, and foaming during the melt mixing can be effectively suppressed.
Thus, in the silane crosslinking method in which the above-mentioned base resin and the silane coupling agent are melt-mixed in a specific mixing mode, by using boehmite and the silane coupling agent in combination, flame retardancy, appearance, and acid resistance are achieved. It has a high level of flexibility.

  In particular, in the present invention, the crosslinking reaction by the condensation using the silanol condensation catalyst in the presence of water in the step (c) is performed after forming the molded body. Thereby, compared with the conventional method of forming a molded body after the final cross-linking reaction, the workability in the process until forming the molded body is excellent.

The production method of the present invention is a production of products requiring flame retardancy (including semi-finished products, parts and members), products requiring flexibility, components of products requiring acid resistance, or members thereof. Can be applied to. The present invention can also be applied to products that require strength, products such as rubber materials, and the like. Therefore, the flame-retardant molded product of the present invention is such a product. At this time, the flame retardant molded product may be a product including the flame retardant crosslinked resin molded product, or may be a product including only the flame retardant crosslinked resin molded product.
Examples of the flame retardant molded product of the present invention include, for example, a coating material for a heat resistant flame retardant insulated wire or a heat resistant flame retardant cable, a rubber alternative wire / cable material, other heat resistant flame retardant wire components, a flame retardant heat resistant sheet, and the like. And flame retardant heat resistant film. Also included are power plugs, connectors, sleeves, boxes, tape substrates, tubes, sheets, packing materials, cushioning materials, anti-vibration materials, wiring materials used for internal and external wiring of electrical and electronic equipment, especially electric wires and optical cables. It is done. Examples of products requiring acid resistance include outdoor electric wires and automobile wiring.

Among the above products, the production method of the present invention is suitably applied particularly to the production of electric wires and optical cables, and these coating materials (insulators and sheaths) can be produced.
When the flame-retardant molded article of the present invention is an extrusion molded article such as an electric wire or cable, preferably, a flame-retardant crosslinkable resin composition is prepared by melting and mixing molding raw materials in an extruder (extrusion coating apparatus). However, the flame retardant crosslinkable resin composition can be produced by a method of extruding the outer periphery of a conductor or the like to coat the conductor or the like and then causing a crosslinking reaction. In this method, even if a large amount of boehmite is added, the flame retardant crosslinkable resin composition is used around a conductor using a general-purpose extrusion coating apparatus without using a special machine such as an electron beam crosslinking machine, or It can be formed by extrusion coating around a conductor in which tensile strength fibers are vertically attached or twisted together. For example, a soft copper single wire or a stranded wire can be used as the conductor. In addition to the bare wire, a conductor plated with tin or an enameled insulating layer can be used as the conductor. The thickness of the insulating layer (the coating layer made of the flame-retardant crosslinkable resin molded product of the present invention) formed around the conductor is not particularly limited, but is usually about 0.15 to 5 mm.

EXAMPLES Hereinafter, although this invention is demonstrated in detail based on an Example, this invention is not limited to these.
In Tables 1 and 2, the numerical values related to the blending amounts in each example represent parts by mass unless otherwise specified.

  In Examples 1 to 20 and Comparative Examples 1 to 4, the following components were used and the respective specifications were set to the conditions shown in Tables 1 and 2, and the evaluation results described later in Tables 1 and 2 are shown. Also shown.

The detail of each compound shown in Table 1 and Table 2 is shown below.
<Base resin>
PE: “NUC7641” (trade name, Nippon Unicar Co., Ltd., linear low density polyethylene resin)
EVA: “EV360” (trade name, manufactured by Mitsui DuPont Polychemical Co., Ltd., ethylene-vinyl acetate copolymer resin)
EP rubber 1: “Nodel 3640” (trade name, manufactured by Dow Chemical Company, ethylene-propylene-ethylidene norbornene rubber, ethylene content 60 mass%, diene content 1.8 mass%)
EP rubber 2: “EPT3092” (trade name, manufactured by Mitsui Chemicals, ethylene-propylene-ethylidenenorbornene rubber, ethylene content 65 mass%, diene content 4.6 mass%)
SEPS: “Septon 4077” (trade name, manufactured by Kuraray Co., Ltd., styrene elastomer, styrene content 30% by mass)
OIL: “Cosmo Neutral 500” (trade name, manufactured by Cosmo Oil Lubricants, paraffin oil)
<Boehmite>
Aluminum hydroxide (Nihon Light Metal Co., Ltd., trade name: B703) is hydrothermally treated (heated at 210 ° C. under an atmosphere of 2 MPa for 3 hours), dehydrated and dried, and then pulverized with a ball mill. 1-3 were obtained.
Boehmite 1: Average primary particle size 1.5 μm, aspect ratio 2.5, BET surface area ratio 5
Boehmite 2: Average primary particle size 0.9 μm, aspect ratio 2.5, BET surface area ratio 15
Boehmite 3: Average primary particle size 2.5 μm, aspect ratio 2.0, BET surface area ratio 3
<Inorganic filler>
Aluminum hydroxide 1: “Hijilite 42M” (trade name, manufactured by Showa Denko KK, surface untreated aluminum hydroxide)
Aluminum hydroxide 2: “Hijilite 42S” (trade name, manufactured by Showa Denko KK, fatty acid (stearic acid) -treated aluminum hydroxide)
<Silane coupling agent>
KBM: “KBM-1003” (trade name, manufactured by Shin-Etsu Chemical Co., Ltd., vinyltrimethoxysilane)
<Organic peroxide>
“Perkadox BC-FF” (trade name, Kayaku Akzo, dicumyl peroxide (DCP), decomposition temperature 151 ° C.)
<Antioxidant (hindered phenol antioxidant)>
“Irganox 1010” (trade name, manufactured by BASF, pentaerythritol-tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate])
<Silanol condensation catalyst>
“ADK STAB OT-1” (trade name, manufactured by ADEKA, dioctyltin dilaurate)

(Examples 1-20 and Comparative Examples 1-4)
In Examples 1 to 19 and Comparative Examples 1 to 4, among the resin components constituting the base resin, EP rubber was used as a carrier resin for the catalyst MB. In Example 20, PE was used as the carrier resin.

First, boehmite or an inorganic filler and a silane coupling agent are introduced into a Toyo Seiki 10 L Henschel mixer at a mass ratio shown in the silane MB column of Table 1 or Table 2, and mixed at room temperature (25 ° C.) for 5 minutes. A powder mixture was obtained (step (a-1)).
Next, the powder mixture obtained as described above, the resin component shown in the silane MB column of Table 1 or Table 2, and the organic peroxide are mixed in a mass ratio shown in Table 1 or Table 2 with a Japanese roll. The mixture was put into a 2 L Banbury mixer manufactured and kneaded at a temperature equal to or higher than the decomposition temperature of the organic peroxide, specifically 200 ° C., for 5 minutes to obtain Silane MB (step (a-2)). The obtained silane MB contains a silane crosslinkable resin obtained by graft reaction of a silane coupling agent to the resin component.

  On the other hand, the carrier resin, the silanol condensation catalyst, and the antioxidant were melt-mixed at 180 ° C. with a Banbury mixer at a mass ratio shown in the catalyst MB column of Table 1 or Table 2 to obtain a catalyst MB (step (b)). ). The catalyst MB is a mixture of a carrier resin and a silanol condensation catalyst.

  Next, silane MB and catalyst MB were charged into a closed ribbon blender and dry blended at room temperature (25 ° C.) for 3 minutes to obtain a dry blend. In each example, the mixing ratio of silane MB and catalyst MB was such that the base resin of silane MB was 95 parts by mass and the carrier resin of catalyst MB was 5 parts by mass.

Next, the obtained dry blend was melt-mixed and molded under the following extrusion molding conditions (1) or (2) to obtain coated conductors (step (c) and step (2)), respectively.
<Extrusion conditions (1)>
The obtained dry blend was subjected to L / D (ratio between screw effective length L and diameter D) = 24 and screw having a screw diameter of 40 mm (feed portion screw temperature 160 ° C., compression portion screw temperature 190 ° C. The head temperature was 190 ° C.). While melt blending the dry blend in this extruder (melt mixing time 5 minutes), the outer circumference of 7 / 0.6 A (conductor diameter 1.8 mm) is extruded at a linear speed of 20 m / min so as to have a coating thickness of 1 mm. Thus, a coated conductor having an outer diameter of 3.8 mm having an extruded product of the flame-retardant crosslinkable resin composition around the conductor was obtained (step (c) and step (2)).

<Extrusion molding condition (2): High temperature extrusion condition>
In the extrusion molding condition (1), a coated conductor was obtained in the same manner as in the extrusion molding condition (1) except that the compression part screw temperature was 210 ° C. and the head temperature was 210 ° C. (step (c) and step) (2)).

The coated conductor obtained by the extrusion molding condition (1) or (2) was allowed to stand for 48 hours in an atmosphere of 60 ° C. and 95% humidity (step (3)).
Thus, the electric wire provided with the coating layer of the flame-retardant crosslinked resin molding was manufactured from the said covered conductor. This flame-retardant crosslinked resin molding has the above-mentioned silane crosslinked resin.

  Each manufactured electric wire was subjected to the following test, and the results are shown in Tables 1 and 2.

<Appearance test 1>
In each electric wire manufactured by bringing the coated conductor obtained under the above extrusion molding condition (1) into contact with water, the appearance of a portion where 20 minutes had elapsed after the dry blend was extruded from the extruder was observed. “A” indicates that the wire appearance is excellent, “B” indicates that there is no problem in the wire appearance (acceptable extent as the wire appearance), and “C” indicates that the wire appearance is problematic. It was. An evaluation of “B” or higher is a passing level of this test.
<Appearance test 2>
In each electric wire produced by bringing the coated conductor obtained under the above extrusion molding condition (2) into contact with water, the appearance of a portion where 20 minutes had elapsed after the dry blend was extruded from the extruder was observed. The case where the appearance as an electric wire was excellent was designated as “A”, the case where there was no problem in the appearance as an electric wire was designated as “B”, and the case where the appearance as an electric wire was problematic was designated as “C”. An evaluation of “B” or higher is a passing level of this test.

<Tensile properties (mechanical properties)>
The tensile test was done about the coating layer (tubular piece) extracted from each electric wire manufactured by making the coated conductor obtained by the said extrusion molding conditions (1) contact with water.
In this tensile test, tensile strength (MPa), 100% modulus (MPa), and tensile elongation (%) were measured in accordance with JIS C 3005 under conditions of 25 mm between marked lines and a tensile speed of 200 mm / min.
In this test, the tensile strength of 12 MPa or more was expressed as “AA” as a particularly excellent level, and the tensile strength of 10 MPa or more and less than 12 MPa was expressed as “A” as an excellent level, and 8 MPa or more and less than 10 MPa. Was expressed as “B” as a pass level of this test, and “C” was expressed as a reject level of this test that was less than 8 MPa.
100% modulus is an index of flexibility, and in this test, what was 6 MPa or less is expressed as “AA” as a particularly excellent level, and what is more than 6 MPa and 7 MPa or less is an excellent level. As “A”, exceeding 7 MPa and 8 MPa or less as “B” as the pass level of this test, and exceeding “8 MPa” as “C” as the failure level of this test.
In this test, the tensile elongation of 300% or more is expressed as “AA” as an excellent level, and the tensile elongation of 200% or more and less than 300% is expressed as “A” as a passing level of this test. What was less than% was represented by "C" as a failure level of this test.

<Flame retardance test>
The flame retardancy test was performed according to the “gradient flame retardancy test” defined in JIS C 3005.
As a test electric wire, each electric wire manufactured by making the covered conductor obtained by the said extrusion molding conditions (1) contact with water was used.
The inclination angle was 60 ° and the combustion time was 30 seconds.
The evaluation was “A” when the flame self-extinguished, and “C” when the flame did not self-extinguish.

<Acid resistance test>
As a test piece, the coating layer (tubular piece) extracted from each electric wire manufactured by making the coated conductor obtained by the said extrusion molding conditions (1) contact with water was used.
5 g of the electric wire was weighed and immersed in 50 mL of each of the following four types of acid solutions at 50 ° C. for 168 hours. Thereafter, the test piece was taken out and its mass W ^A (g) was measured. About each acid solution, the mass change rate (%) before and behind immersion of a test piece was calculated | required from the following formula.
Formula: Mass change rate (%) = [W ^A (g) −5 (g)] / 5 (g) × 100
In this test, in all the acid solutions, the mass change rate before and after the immersion was within 5% was designated as “A”, and in one or more acid solutions, the value exceeding 5% was designated as “C”.
Acid solution: 10% by mass sulfuric acid, 10% by mass nitric acid, 10% by mass hydrochloric acid and 10% by mass acetic acid

From the results of Tables 1 and 2, the following was found.
When aluminum hydroxide was used as the inorganic filler and when the amount of boehmite was too large, both were inferior to at least one of appearance and flexibility, and these were not compatible (Comparative Example 2). ~ 4). Moreover, even if it used boehmite, when there were too few compounding quantities, the flame retardance was not enough (comparative example 1).
On the other hand, when a specific amount of boehmite was used in combination with a silane coupling agent using a base resin having a specific composition, all had a high level of appearance, flexibility and acid resistance (Examples 1 to 1). 20). In particular, it was possible to effectively prevent the appearance from being deteriorated even under high temperature extrusion conditions. Furthermore, sufficient performance was exhibited in mechanical properties (tensile strength and tensile elongation).

Claims (9)

A method for producing a flame-retardant crosslinked resin molded article, comprising the following step (1), step (2) and step (3),
Step (1): 0.01 to 0.6 parts by mass of organic peroxide, 60 to 200 parts by mass of boehmite, and 100% by mass of the base resin react with the boehmite, thereby silanol condensation.
Possible reaction sites and graphs capable of grafting to the base resin in the presence of radicals
A step of melt-mixing 2 to 15 parts by mass of a silane coupling agent having a phthalating reaction site and a silanol condensation catalyst to obtain a mixture Step (2): The mixture obtained in Step (1) above is molded. Step of obtaining a molded body Step (3): Step of contacting the molded body obtained in the step (2) with water to obtain a flame retardant crosslinked resin molded body The base resin is at least a polyolefin resin and ethylene rubber. 1 type, and 100% by mass or less of the polyolefin resin, 100% by mass or less of the ethylene rubber, 35% by mass or less of styrene elastomer, and 40% by mass or less of oil,
In carrying out the step (1), when all of the base resin is melt-mixed in the following step (a-2), the step (1) includes the following step (a-1), step (a-2) and In the case of having a step (c) and melting and mixing a part of the base resin in the following step (a-2), the step (1) is the following step (a-1), step (a-2), The manufacturing method of a flame-retardant crosslinked resin molding which has a process (b) and a process (c).
Step (a-1): Step of preparing a mixture by mixing at least the boehmite and the silane coupling agent Step (a-2): The mixture and the whole or part of the base resin are mixed with the organic peracid. by melt mixing at a decomposition temperature or more of the temperature of the organic peroxide in the presence of a product, prior to
A graft reaction between the grafting reaction site and the base resin
Step of preparing a flame retardant silane master batch containing a run crosslinkable resin Step (b): Melting and mixing the remainder of the base resin and the silanol condensation catalyst,
Step of preparing a catalyst master batch Step (c): Step of melt mixing the flame retardant silane master batch and the silanol condensation catalyst or the catalyst master batch.   The flame retardant according to claim 1, wherein the base resin contains 50% by mass or less of polyolefin resin, 10 to 100% by mass of ethylene rubber, 35% by mass or less of styrene elastomer, and 40% by mass or less of oil. A method for producing a crosslinked resin molded article.   The base resin contains 20 to 40% by mass of polyolefin resin, 10 to 60% by mass of ethylene rubber, 10 to 35% by mass of styrene elastomer, and 10 to 40% by mass of oil. The manufacturing method of the flame-retardant crosslinked resin molding of description.   The manufacturing method of the flame-retardant crosslinked resin molding of any one of Claims 1-3 whose compounding quantity of the said boehmite is 60-170 mass parts with respect to 100 mass parts of base resins. In the presence of 0.01 to 0.6 parts by weight of organic peroxide, 60 to 200 parts by weight of boehmite, a reactive site capable of silanol condensation, and radicals, with respect to 100 parts by weight of base resin and 60 to 200 parts by weight of boehmite. A flame retardant crosslinkable resin composition comprising a step (1) of melt-mixing 2 to 15 parts by mass of a silane coupling agent having a grafting reaction site capable of grafting to the base resin and a silanol condensation catalyst. A manufacturing method comprising:
The base resin contains at least one of a polyolefin resin and ethylene rubber, the polyolefin resin is 100% by mass or less, the ethylene rubber is 100% by mass or less, the styrene elastomer is 35% by mass or less, and an oil At a ratio of 40% by mass or less,
In carrying out the step (1), when all of the base resin is melt-mixed in the following step (a-2), the step (1) includes the following step (a-1), step (a-2) and In the case of having a step (c) and melting and mixing a part of the base resin in the following step (a-2), the step (1) is the following step (a-1), step (a-2), A method for producing a flame-retardant crosslinkable resin composition, comprising steps (b) and (c).
Step (a-1): Step of preparing a mixture by mixing at least the boehmite and the silane coupling agent Step (a-2): The mixture and the whole or part of the base resin are mixed with the organic peracid. by melt mixing at a decomposition temperature or more of the temperature of the organic peroxide in the presence of a product, prior to
A graft reaction between the grafting reaction site and the base resin
Step of preparing a flame retardant silane master batch containing a run crosslinkable resin Step (b): Melting and mixing the remainder of the base resin and the silanol condensation catalyst,
Step of preparing a catalyst master batch Step (c): Step of melt mixing the flame retardant silane master batch and the silanol condensation catalyst or the catalyst master batch.   A flame retardant crosslinkable resin composition produced by the method for producing a flame retardant crosslinkable resin composition according to claim 5. A flame-retardant crosslinked resin molded article produced by the method for producing a flame-retardant crosslinked resin molded article according to any one of claims 1 to 4 .   A flame-retardant molded article comprising the flame-retardant crosslinked resin molded article according to claim 7. In the presence of 0.01 to 0.6 parts by weight of organic peroxide, 60 to 200 parts by weight of boehmite, a reactive site capable of silanol condensation, and radicals, with respect to 100 parts by weight of base resin and 60 to 200 parts by weight of boehmite. 2 to 15 parts by weight of a silane coupling agent having a grafting reaction site capable of undergoing a graft reaction to the base resin and a silanol condensation catalyst are difficult to be used in the production of a flame retardant crosslinkable resin composition. A flammable silane masterbatch,
The base resin contains at least one of a polyolefin resin and ethylene rubber, the polyolefin resin is 100% by mass or less, the ethylene rubber is 100% by mass or less, the styrene elastomer is 35% by mass or less, and an oil At a ratio of 40% by mass or less,
A mixture is prepared by mixing at least the boehmite and the silane coupling agent, and the decomposition temperature of the organic peroxide is obtained by mixing the obtained mixture and all or part of the base resin in the presence of the organic peroxide. A flame-retardant silane masterbatch containing a silane crosslinkable resin, which is obtained by melt-mixing at the above temperature to cause a grafting reaction between the grafting reaction site and the base resin .