JP6767438B2 - Heat-resistant silane cross-linked resin molded body and its manufacturing method, heat-resistant silane cross-linked resin composition and its manufacturing method, silane masterbatch, and heat-resistant product using heat-resistant silane cross-linked resin molded body - Google Patents

Description

The present invention relates to a heat-resistant silane-crosslinked resin molded product and a method for producing the same, a heat-resistant silane-crosslinked resin composition and a method for producing the same, a silane masterbatch, and a heat-resistant product using the heat-resistant silane-crosslinked resin molded product.
In particular, a heat-resistant silane cross-linked resin molded product having excellent appearance, preferably flame-retardant and mechanical properties, which is less likely to cause rough appearance or bumps even if the extruder is temporarily stopped and restarted during molding, and its manufacture. Method, silane master batch capable of forming this heat-resistant silane-crosslinked resin molded product, heat-resistant silane-crosslinked resin composition and its manufacturing method, and heat-resistant silane-crosslinked resin molded product as an insulator or sheath of an electric wire. Regarding the heat-resistant product used.

Insulated wires, cables, cords and optical fiber core wires used for internal and external wiring of electrical and electronic equipment, optical fiber cords have flame retardancy, heat resistance, and mechanical properties (for example, tensile properties, wear resistance). Various characteristics such as are required. As the material used for these wiring materials, a resin composition containing a large amount of metal hydrates such as magnesium hydroxide and aluminum hydroxide is used.

Further, the wiring material used for electric and electronic devices may be heated to 80 to 105 ° C., further to about 125 ° C. when used for a long time, and heat resistance to this may be required. In such a case, a method of cross-linking the coating material by an electron beam cross-linking method, a chemical cross-linking method, or the like is adopted for the purpose of imparting high heat resistance to the wiring material.

Conventionally, as a method of cross-linking a polyolefin resin such as polyethylene, an electron beam cross-linking method in which an electron beam is irradiated to bridge (also referred to as cross-linking), or an organic peroxide or the like is decomposed by applying heat after molding to carry out a cross-linking reaction. A chemical cross-linking method and a silane cross-linking method are known.
Among these cross-linking methods, the silane cross-linking method often does not require special equipment, and can be used in a wide range of fields.
The silane cross-linking method is a silane graft polymer obtained by grafting a hydrolyzable silane coupling agent having an unsaturated group with a polymer in the presence of an organic peroxide, and then silane grafting in the presence of a silanol condensation catalyst. This is a method for obtaining a crosslinked molded product by contacting a polymer with water.

Specifically, a method for producing a halogen-free heat-resistant silane crosslinked resin includes, for example, a silane masterbatch in which a polyolefin resin is grafted with a hydrolyzable silane coupling agent having an unsaturated group, and a polyolefin resin and an inorganic filler. This is a method in which a heat-resistant masterbatch obtained by kneading and a catalyst masterbatch containing a silane condensation catalyst are melt-mixed. However, in this method, when the amount of the inorganic filler exceeds 100 parts by mass with respect to 100 parts by mass of the polyolefin resin, the silane masterbatch and the heat-resistant masterbatch are dry-mixed and then uniformly mixed in a single-screw extruder or a twin-screw extruder. It becomes difficult to melt and knead. Therefore, there arises a problem that the appearance is deteriorated and the physical properties are significantly deteriorated. In addition, there arises a problem that the extrusion load is high and molding cannot be performed.
Therefore, in order to uniformly melt and knead the silane masterbatch and the heat-resistant masterbatch after dry mixing, the proportion of the inorganic filler is limited as described above. Therefore, it is difficult to make it more flame-retardant and heat-resistant.

Usually, when such an inorganic filler exceeds 100 parts by mass with respect to 100 parts by mass of the polyolefin resin, a continuous kneader, a closed mixer such as a pressure kneader or a Banbury mixer is generally used for kneading. is there.
On the other hand, when silane grafting is performed with a kneader or a Banbury mixer, the hydrolyzable silane coupling agent having an unsaturated group is generally highly volatile and has a problem that it volatilizes before the graft reaction. Therefore, it was very difficult to prepare a desired silane crosslinked masterbatch.

Therefore, when preparing a heat-resistant silane masterbatch with a Banbury mixer or kneader, the heat-resistant masterbatch obtained by melting and mixing the polyolefin resin and the inorganic filler is mixed with a hydrolyzable silane coupling agent having an unsaturated group. A method of adding an organic peroxide and causing a graft reaction by a uniaxial extruder can be considered. However, in this method, the appearance of the molded product may be poor due to the variation in the reaction. In addition, the amount of the inorganic filler compounded in the masterbatch must be very large, and the extrusion load may become significantly large. These make it very difficult to manufacture the molded product. Therefore, a desired material or molded product could not be obtained. In addition, there are two manufacturing processes, which is a problem in terms of manufacturing cost.

In Patent Document 1, an inorganic filler, a silane coupling agent, an organic peroxide, and a cross-linking catalyst in which a resin component obtained by mixing a polyolefin resin and a maleic anhydride-based resin is surface-treated with a silane coupling agent are used in a kneader. A method of forming with a uniaxial extruder after sufficiently melt-kneading has been proposed.
Further, in Patent Documents 2 to 4, a vinyl aromatic thermoplastic elastomer composition in which a block copolymer or the like is used as a base resin and a softening agent for non-aromatic rubber is added as a softening agent is treated with a silane surface-treated inorganic. A method of partial cross-linking using an organic peroxide via a filler has been proposed.
Further, in Patent Document 5, an organic peroxide, a silane coupling agent, and a metal hydrate are collectively melt-kneaded with respect to a base material, further melt-molded together with a silanol condensation catalyst, and then crosslinked in the presence of water. As a result, a method for easily obtaining a cable having heat resistance has been proposed.

Japanese Unexamined Patent Publication No. 2001-101928 Japanese Unexamined Patent Publication No. 2000-143935 Japanese Unexamined Patent Publication No. 2000-315424 Japanese Unexamined Patent Publication No. 2001-240719 Japanese Unexamined Patent Publication No. 2012-255077

However, in the method described in Patent Document 1, the resin is partially crosslinked during melt-kneading with a Banbury mixer or a kneader, resulting in a poor appearance of the obtained molded product (a large number of lump-shaped products protruding from the surface). May cause formation). Further, most of the silane coupling agents other than the silane coupling agent surface-treated with the inorganic filler may volatilize or condense. Therefore, not only the desired heat resistance cannot be obtained, but also the condensation between the silane coupling agents may cause deterioration of the appearance of the electric wire.
Further, even with the methods described in Patent Documents 2 to 4, since the resin does not yet have a sufficient network structure, the bond between the resin and the inorganic filler is broken at a high temperature. Therefore, the molded product may melt at a high temperature, and the insulating material may melt during soldering, for example, of the electric wire. Further, when the molded product is secondarily processed, it may be deformed or foamed. Further, when heated to about 200 ° C. for a short time, the appearance may be significantly deteriorated or deformed.

The method described in Patent Document 5 can solve the above-mentioned problems of the methods described in Patent Documents 1 to 4 to some extent. However, in this method, when the silane crosslinkable flame-retardant polyolefin formed by batch melt-kneading is extruded together with the silanol condensation catalyst, the appearance is liable to be rough or poor appearance due to lumps (also referred to as appearance lumps).
In particular, if the extruder is temporarily stopped when cleaning the extruder, changing steps, or adjusting the eccentricity, the molded product to be molded after that tends to have a rough appearance or uneven appearance, resulting in poor appearance. It was confirmed that it occurred.

The present invention solves the above-mentioned problems, and even if the extruder is stopped and the operation is restarted, the appearance is less likely to be rough or bumpy, and the appearance is excellent, preferably flame-retardant and mechanical properties are also excellent. It is an object of the present invention to provide a method for producing a heat-resistant silane-crosslinked resin molded product, and to provide a heat-resistant silane-crosslinked resin molded product which is less likely to cause rough appearance or lumps and has an excellent appearance, preferably flame retardancy and excellent mechanical properties. And.
Another object of the present invention is to provide a silane masterbatch, a heat-resistant silane-crosslinked resin composition, and a method for producing the same, which can form the heat-resistant silane-crosslinked resin molded product.
Another object of the present invention is to provide a heat-resistant product using the heat-resistant silane-crosslinked resin molded product obtained by the method for producing the heat-resistant silane-crosslinked resin molded product.

That is, the subject of the present invention has been achieved by the following means.
(1) With respect to 100 parts by mass of a polyolefin resin containing polypropylene and 40% by mass or less of a mineral oil softener , 0.01 parts by mass or more and 0.6 parts by mass or less of an organic peroxide and 10 parts by mass or more and 400 parts by mass of an inorganic filler. More than 4 parts by mass and 15.0 parts by mass or less of the silane coupling agent having a graft-reactive group and a hydrolyzable group are melt-kneaded at a temperature equal to or higher than the decomposition temperature of the organic peroxide. A step (a) of preparing a silane master batch by graft-reacting the silane coupling agent with the polyolefin resin.
The step (b) of mixing the silane masterbatch and the silanol condensation catalyst to obtain a mixture, and
The step (c) of molding the mixture to obtain a molded product,
Wherein the compact method of manufacturing a heat-resistant silane crosslinkable resin molded body have a the step (d) of obtaining a heat resistant silane crosslinked resin molded product into contact with water,
In performing the step (a), the organic peroxide, the inorganic filler, and the silane coupling agent are mixed at a temperature lower than the decomposition temperature of the organic peroxide, and then the obtained mixture and the polyolefin resin are used. Melt and knead,
Wherein the inorganic filler is boron nitride, silica, carbon, clay, zinc oxide, tin oxide, titanium oxide, molybdenum oxide, antimony trioxide, quartz, talc, zinc borate, zinc borate, hydroxy stannate, zinc stannate and At least one selected from the group consisting of calcium carbonate,
A method for producing a heat-resistant silane crosslinked resin molded product.
(2) The method for producing a heat-resistant silane crosslinked resin molded product according to (1) , wherein the mixed amount of the silane coupling agent is 6 parts by mass or more and 15.0 parts by mass or less with respect to 100 parts by mass of the polyolefin resin. ..
(3) The method for producing a heat-resistant silane crosslinked resin molded product according to (1) or (2) , wherein the silane coupling agent is vinyltrimethoxysilane or vinyltriethoxysilane.
(4) The heat-resistant silane crosslinked resin molded product according to any one of (1) to (3) , wherein the inorganic filler is at least one selected from the group consisting of silica, calcium carbonate and antimony trioxide. Production method.
(5) The method for producing a heat-resistant silane crosslinked resin molded product according to any one of (1) to (4) , wherein the melt kneading in the step (a) is performed with a closed mixer.
(6) The method for producing a heat-resistant silane crosslinked resin molded product according to any one of (1) to (5) , wherein the silanol condensation catalyst is not substantially mixed in the step (a).
(7) With respect to 100 parts by mass of a polyolefin resin containing polypropylene and 40% by mass or less of a mineral oil softener , 0.01 parts by mass or more and 0.6 parts by mass or less of an organic peroxide and 10 parts by mass or more and 400 parts by mass of an inorganic filler. More than 4 parts by mass and 15.0 parts by mass or less of the silane coupling agent having a graft-reactive group and a hydrolyzable group are melt-kneaded at a temperature equal to or higher than the decomposition temperature of the organic peroxide. A step (a) of preparing a silane master batch by graft-reacting the silane coupling agent with the polyolefin resin.
A manufacturing method of the silane masterbatch and a silanol condensation catalyst were mixed to obtain the mixture step (b) and heat silane crosslinkable resin composition which have a,
In performing the step (a), the organic peroxide, the inorganic filler, and the silane coupling agent are mixed at a temperature lower than the decomposition temperature of the organic peroxide, and then the obtained mixture and the polyolefin resin are used. Melt and knead,
Wherein the inorganic filler is boron nitride, silica, carbon, clay, zinc oxide, tin oxide, titanium oxide, molybdenum oxide, antimony trioxide, quartz, talc, zinc borate, zinc borate, hydroxy stannate, zinc stannate and At least one selected from the group consisting of calcium carbonate,
A method for producing a heat-resistant silane crosslinkable resin composition.

(8) A thermosetting silane crosslinkable resin composition produced by the production method according to (7) above .
(9) A heat-resistant silane crosslinked resin molded product produced by the production method according to any one of (1) to (6 ) above .
(10) The heat-resistant silane crosslinked resin molded body according to (9) , wherein the heat-resistant silane crosslinked resin molded body contains the polyolefin resin formed by cross-linking with the inorganic filler via a silanol bond.
(11) A heat-resistant product containing the heat-resistant silane crosslinked resin molded product according to (9) or (10) above .
(12) The heat-resistant product according to (11) , wherein the heat-resistant silane crosslinked resin molded product is provided as a coating for an electric wire or an optical fiber cable.
(13) With respect to 100 parts by mass of a polyolefin resin containing polypropylene and 40% by mass or less of a mineral oil softener , 0.01 parts by mass or more and 0.6 parts by mass or less of an organic peroxide, and zinc oxide, silica, carbon, At least one selected from the group consisting of clay, zinc oxide, tin oxide, titanium oxide, molybdenum oxide, antimony trioxide , quartz, talc, zinc borate, zinc borate, zinc hydroxytinate , zinc tinate and calcium carbonate. 10 parts by mass or more and 400 parts by mass or less of a certain inorganic filler, and more than 4 parts by mass of a silane coupling agent having a graft-reactive group and a hydrolyzable group and 15.0 parts by mass or less of the organic peroxide. A silane master batch obtained by melt-kneading at a temperature equal to or higher than the decomposition temperature and graft-reacting the silane coupling agent with the polyolefin resin .
The melt-kneading mixes the organic peroxide, the inorganic filler, and the silane coupling agent at a temperature lower than the decomposition temperature of the organic peroxide, and then melt-mixes the obtained mixture and the polyolefin resin. Silane masterbatch performed by smelting.

In the method for producing a heat-resistant silane crosslinked resin molded product of the present invention, a silane coupling agent of more than 4 parts by mass and 15 parts by mass or less with respect to 100 parts by mass of a polyolefin resin is used in the presence of an inorganic filler and an organic peroxide. By melt-mixing, it is possible to produce a silane crosslinked resin molded article having an excellent appearance even if the extruder is temporarily stopped and then the operation is restarted.

According to the method for producing a heat-resistant silane crosslinked resin molded product of the present invention, both the crosslinking reaction between polyolefin resins and the condensation reaction between silane coupling agents can be suppressed, and the silane crosslinked resin has a beautiful appearance. A molded product can be manufactured.

Further, in the method for producing a heat-resistant silane crosslinked resin molded product of the present invention, the inorganic filler and the silane coupling agent are mixed in a predetermined ratio before and / or during kneading with the polyolefin resin. As a result, volatilization of the silane coupling agent during kneading can be suppressed, and a heat-resistant silane crosslinked resin molded product can be efficiently produced. Moreover, excellent flame retardancy and mechanical properties can be imparted to the heat-resistant silane crosslinked resin molded product. Further, a highly heat-resistant silane crosslinked resin molded product to which a large amount of inorganic filler is added can be produced without using a special machine such as an electron beam crosslinker.

Therefore, according to the present invention, even if the operation of the extruder is stopped and then restarted, the appearance is less likely to be roughened or bumpy, and the appearance is excellent, preferably flame-retardant and heat-resistant silane crosslinked resin molding having excellent mechanical properties. A method for producing a body and a heat-resistant silane crosslinked resin molded product obtained by this production method can be provided. Further, it is possible to provide a silane masterbatch, a heat-resistant silane-crosslinked resin composition capable of forming this heat-resistant silane-crosslinked resin molded product, and a method for producing the same. Further, it is possible to provide a heat-resistant product using the heat-resistant silane-crosslinked resin molded product obtained by the method for producing the heat-resistant silane-crosslinked resin molded product.

The above and other features and advantages of the present invention will become more apparent from the description below.

The "method for producing a heat-resistant silane crosslinked resin molded product" of the present invention has the following steps (a) to (d). The "method for producing a heat-resistant silane crosslinkable resin composition" of the present invention has the following steps (a) and (b), and the steps (c) and (d) are not essential steps.
As described above, the "method for producing a heat-resistant silane-crosslinked resin molded product" of the present invention and the "method for producing a heat-resistant silane-crosslinked resin composition" of the present invention have the following steps (c) and (d). Other than that, it is basically the same. Therefore, the "method for producing a heat-resistant silane-crosslinked resin molded product" of the present invention and the "method for producing a heat-resistant silane-crosslinked resin composition" of the present invention (in the description of the common parts of both, these are combined in the present invention. The manufacturing method of the invention) will also be described below.

Hereinafter, preferred embodiments of the present invention will be described in detail.

Step (a): With respect to 100 parts by mass of the polyolefin resin, 0.01 parts by mass or more and 0.6 parts by mass or less of the organic peroxide, 10 parts by mass or more and 400 parts by mass or less of the inorganic filler, and 4 parts by mass of the silane coupling agent. 15.0 parts by mass or less is melt-kneaded at a temperature equal to or higher than the decomposition temperature of the organic peroxide to prepare a silane master batch (b): A silane master batch and a silanol condensation catalyst are mixed. Step (c): Step of molding the mixture to obtain a molded product Step (d): Step of bringing the molded product into contact with water to obtain a heat-resistant silane crosslinked resin molded product. , To obtain a uniform mixture.

First, each component used in the present invention will be described.
<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 is conventionally known as a heat-resistant resin composition. Can be used.
For example, polyethylene (PE), polypropylene (PP), ethylene-α-olefin copolymer, block copolymer of polypropylene and ethylene-α-olefin resin, and a polyolefin having an acid copolymer component or an acid ester copolymer component. Examples thereof include polymers composed of polymers and polymers such as rubbers, elastomers, styrene elastomers, and ethylene-propylene rubbers (for example, ethylene-propylene-diene rubbers).
Among these, polyethylene, polypropylene, and ethylene-α-olefins are both highly receptive to various inorganic fillers such as metal hydrates and can maintain mechanical strength even when a large amount of inorganic filler is blended. Resins such as polymers, polyolefin copolymers having an acid copolymer component or an acid ester copolymer component, styrene elastomers, and ethylene-propylene rubber are suitable. These polyolefin resins may be used alone or in combination of two or more.

Polyethylene is not particularly limited as long as it is a polymer containing an ethylene component as a main component. Polyethylene is a homopolymer consisting only of ethylene, a copolymer of ethylene and α-olephyrene (excluding propylene) of 5 mol% or less, and 1 mol% or less having only carbon, oxygen and hydrogen atoms as functional groups with ethylene. Includes copolymers with non-olefins (eg, JIS K 6748). As the above-mentioned α-olephyrene and non-olefin, known ones conventionally used as a copolymerization component of polyethylene can be used without particular limitation.
Examples of the polyethylene that can be used in the present invention include high-density polyethylene (HDPE), low-density polyethylene (LDPE), ultra-high-density polyethylene (UHMW-PE), linear low-density polyethylene (LLDPE), and ultra-low-density polyethylene (VLDPE). Can be mentioned. Of these, linear low-density polyethylene (LLDPE) and low-density polyethylene (LDPE) are preferable. One type of polyethylene may be used alone, or two or more types may be used in combination.

Polypropylene is not particularly limited as long as it is a polymer containing a propylene component as a main component. In addition to the homopolymer of propylene, polypropylene includes ethylene-propylene copolymers such as random polypropylene and block polypropylene as copolymers.
Here, "random polypropylene" refers to a copolymer of propylene and ethylene having an ethylene component content of 1 to 5% by mass. Further, "block polypropylene" is a composition containing homopolypropylene and an ethylene-propylene copolymer, has an ethylene component content of about 5 to 15% by mass, and the ethylene component and the propylene component exist as independent components. It means something to do.
One type of polypropylene may be used alone, or two or more types may be used in combination.

Preferred examples of the ethylene-α-olefin copolymer include a copolymer of ethylene and an α-olefin having 3 to 12 carbon atoms (excluding those contained in the above-mentioned polyethylene and polypropylene).
Specific examples of the α-olefin constituents in the ethylene-α-olefin copolymer include propylene, 1-butene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-decene, 1-dodecene and the like. Each component of is mentioned. The ethylene-α-olefin copolymer is preferably a copolymer of ethylene and an α-olefin having 3 to 12 carbon atoms (excluding those contained in polyethylene and polypropylene). Specifically, ethylene-propylene copolymers (excluding those contained in polypropylene), ethylene-butylene copolymers, ethylene-α-olefin copolymers synthesized in the presence of a single-site catalyst, etc. Can be mentioned. The ethylene-α-olefin copolymer may be used alone or in combination of two or more.

Examples of the acid copolymerization component or acid ester copolymerization component in the polyolefin copolymer having an acid copolymerization component or acid ester copolymerization component include carboxylic acid compounds such as (meth) acrylic acid, vinyl acetate and (meth) acrylic. Examples thereof include acid ester compounds such as alkyl acid. Here, the alkyl group of the alkyl (meth) acrylate is preferably one having 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 copolymers having an acid copolymer component or an acid ester copolymer component (excluding those contained in polyethylene) include ethylene-vinyl acetate copolymers, ethylene- (meth) acrylic acid copolymers, and ethylene. -(Meta) alkyl acrylate copolymers and the like can be mentioned. Among these, an ethylene-vinyl acetate copolymer, an ethylene-methyl acrylate copolymer, an ethylene-ethyl acrylate copolymer, and a butyl ethylene-acrylate copolymer are preferable, and further, acceptability and heat resistance of an inorganic filler. From this point of view, an ethylene-vinyl acetate copolymer and an ethylene-ethyl acrylate copolymer are preferable. The polyolefin copolymer having an acid copolymer component or an acid ester copolymer component may be used alone or in combination of two or more.

The styrene-based elastomer refers to an elastomer containing an aromatic vinyl compound in the molecule. Therefore, in the present invention, even if the molecule contains an ethylene component, if it contains an aromatic vinyl compound component, it is classified as a styrene-based elastomer.
Examples of such styrene-based elastomers include block copolymers and random copolymers of conjugated diene compounds and aromatic vinyl compounds, and hydrogenated products thereof. Examples of the aromatic vinyl compound include styrene, p- (t-butyl) styrene, α-methylstyrene, p-methylstyrene, divinylbenzene, 1,1-diphenylstyrene, N, N-diethyl-p-aminoethyl. Examples thereof include styrene and vinyltoluene. Of these, styrene is preferable as the aromatic vinyl compound. This aromatic vinyl compound 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. Of these, butadiene is preferable as the conjugated diene compound. This conjugated diene compound may be used alone or in combination of two or more. Further, as the styrene-based elastomer, an elastomer that does not contain a styrene component and contains an aromatic vinyl compound other than styrene may be used by the same production method.

Examples of the styrene-based elastomer include styrene-ethylene-butylene-styrene block copolymer (SEBS), styrene-isoprene-styrene block copolymer (SIS), hydride SBS, and styrene-ethylene-ethylene-propylene-styrene block. Styrene-ethylene-propylene-styrene block copolymer (SEPS), hydride SIS, hydride styrene-butadiene rubber (HSBR), hydride acrylonitrile-butadiene rubber (HNBR), etc. can be mentioned. it can.
As the styrene-based elastomer, it is preferable to use SEPS, SEEPS or SEBS having a styrene component content of 10 to 40% alone or in combination of two or more thereof.
Commercially available products can be used as the styrene elastomer, for example, Septon 4077, Septon 4055, Septon 8105 (all trade names, manufactured by Kuraray), Dynaron 1320P, Dynaron 4600P, 6200P, 8601P, 9901P (all Product name, manufactured by JSR Corporation) and the like.

The polyolefin resin, that is, the polymer may be acid-modified. The acid used for acid denaturation is not particularly limited, and examples thereof include unsaturated carboxylic acid or a derivative thereof. Examples of unsaturated carboxylic acids include maleic acid, itaconic acid, fumaric acid and the like. Examples of the unsaturated carboxylic acid derivative include maleic acid monoester, maleic acid diester, maleic anhydride, itaconic acid monoester, itaconic acid diester, itaconic anhydride, fumaric acid monoester, fumaric acid diester, fumaric anhydride and the like. Be done. Among these, maleic acid or maleic anhydride is preferable. The amount of acid modification is usually about 0.1 to 7% by mass in one molecule of the acid-modified polyolefin resin.

The polyolefin resin may contain various oils used as plasticizers or softeners, if desired. Examples of such oils include plasticizers used for polyolefin resins and oils as mineral oil softeners for rubber. The mineral oil softener is a mixed oil containing three components: an oil composed of a hydrocarbon having an aromatic ring, an oil composed of a hydrocarbon having a naphthen ring, and an oil composed of a hydrocarbon having a paraffin chain. Paraffin oils are those in which the number of carbon atoms constituting the hydrocarbon having a paraffin chain accounts for 50% or more of the total number of carbon atoms, and naphthenic oil and aromatics are those in which the number of carbon atoms constituting the hydrocarbon having a naphthen ring is 30 to 40%. Hydrocarbons having a ring having 30% or more carbon atoms are called aroma oils and are distinguished. Among these, liquid or low molecular weight synthetic softeners, paraffin oil, and naphthenic oil are preferably used, and paraffin oil is particularly preferably used. Examples of such oils include Diana process oils PW90 and PW380 (trade names, all manufactured by Idemitsu Kosan Co., Ltd.) and Cosmo Neutral 500 (manufactured by Cosmo Oil Co., Ltd.).

When the polyolefin resin contains an oil, the oil is preferably 80% by mass or less, preferably 80% by mass or less, based on the total mass of the above-mentioned polymer and the oil contained in the polyolefin resin in terms of heat resistance, crosslinking performance and strength. It is more preferably mass% or less, and further preferably 40 mass% or less. The minimum oil content is 0% by mass, but it can be, for example, 20% by mass or more. That is, the polyolefin resin is preferably 20% by mass or more, more preferably 45% by mass or more, and further preferably 60% by mass or more, based on the total mass. The maximum content of the polyolefin resin is 100% by mass, but it can be, for example, 80% by mass or less.

<Organic peroxide>
The organic peroxide generates radicals by thermal decomposition to promote the grafting reaction of the silane coupling agent to the polyolefin resin. In particular, when the silane coupling agent contains an ethylenically unsaturated group, it works to promote the grafting reaction by the radical reaction between the ethylenically unsaturated group and the polyolefin resin (including the reaction of extracting hydrogen radicals from the polyolefin resin). To do. The organic peroxide is not particularly limited as long as it generates radicals. For example, compounds represented by the general formulas: R ^1- OO-R ² , R ^1- OO-C (= O) R ³ , R ⁴ C (= O) -OO (C = O) R ⁵ are preferably used. Be done. Here, R ¹ , R ² , R ³ , R ⁴ and R ⁵ independently represent an alkyl group, an aryl group or an acyl group, respectively. Of these, in the present invention, it is preferable that R ¹ , R ² , R ³ , R ⁴ and R ⁵ are all alkyl groups, or one of them is an alkyl group and the rest is an acyl group.

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

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

<Inorganic filler>
The inorganic filler can be used without particular limitation as long as it has a reaction site such as a silanol group of a silane coupling agent and a site capable of forming a hydrogen bond or a site capable of chemically bonding by a covalent bond on its surface. Examples of the site of this inorganic filler that can be chemically bonded to the reaction site of the silane coupling agent include an OH group (hydroxyl group, water molecule of water-containing or water of crystallization, OH group such as carboxy group), amino group, SH group and the like. Be done.
Examples of such inorganic fillers include aluminum hydroxide, magnesium hydroxide, calcium carbonate, magnesium carbonate, calcium silicate, magnesium silicate, calcium oxide, magnesium oxide, aluminum oxide, aluminum nitride, aluminum borate, whiskers, and water. Metal hydrates such as aluminum silicate, hydrated magnesium silicate, basic magnesium carbonate, hydrotalcite and other compounds having hydroxyl groups or crystalline water, boron nitride, silica (crystalline silica, amorphous). Silica, etc.), carbon, clay, zinc oxide, tin oxide, titanium oxide, molybdenum oxide, antimony trioxide, silicone compound, quartz, talc, zinc borate, white carbon, zinc borate, zinc hydroxytinate, zinc tint can do.
Among these, the inorganic filler is preferably at least one of silica, aluminum hydroxide, magnesium hydroxide, calcium carbonate, magnesium carbonate, zinc borate, and zinc hydroxytinate, and silica, aluminum hydroxide, magnesium hydroxide, and carbonic acid. More preferably, at least one selected from the group consisting of calcium and antimony trioxide.
As the inorganic filler, one type may be blended alone, or two or more types may be used in combination.

The average particle size of the inorganic filler is preferably 0.2 to 10 μm, more preferably 0.3 to 8 μm, further preferably 0.4 to 5 μm, and particularly preferably 0.4 to 3 μm. If the average particle size of the inorganic filler is less than 0.2 μm, the inorganic filler may cause secondary aggregation when mixed with the silane coupling agent, which may deteriorate the appearance of the molded product or cause bumps. On the other hand, if it exceeds 10 μm, the appearance may be deteriorated, the holding effect of the silane coupling agent may be deteriorated, and a problem may occur in cross-linking. The average particle size is determined by an optical particle size measuring device such as a laser diffraction / scattering type particle size distribution measuring device, which is dispersed with alcohol or water.

As the inorganic filler, an inorganic filler surface-treated with a silane coupling agent can be used. Examples of the silane coupling agent surface-treated magnesium hydroxide include commercially available magnesium hydroxide products (Kisuma 5L, Kisuma 5P (trade names, manufactured by Kyowa Chemical Industry Co., Ltd.), etc.), aluminum hydroxide, and the like.

<Silane coupling agent>
The silane coupling agent may have a group capable of graft-reacting with the polyolefin resin in the presence of radicals and a group capable of chemically bonding with the inorganic filler, and the hydrolyzable silane having a hydrolyzable group at the terminal. Coupling agents are preferred. The silane coupling agent preferably has a group containing an amino group, a glycidyl group or an ethylenically unsaturated group at the terminal and a group containing a hydrolyzable group, and more preferably ethylene at the terminal. It is a silane coupling agent having a group containing a sex unsaturated group and a group containing a hydrolyzable group. The group containing an ethylenically unsaturated group is not particularly limited, and examples thereof include a vinyl group, an allyl group, a (meth) acryloyloxy group, a (meth) acryloyloxyalkylene group, and a p-styryl group. Further, these silane coupling agents may be used in combination with other silane coupling agents having a terminal group.

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

In the general formula _{(I), R a11} is a group containing an ethylenically unsaturated _{group, 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 or different from each other.

Represented silane coupling agent R _a11 are the general formula (1), preferably a group containing an ethylenically unsaturated group, a group containing an ethylenically unsaturated group is as described above, preferably vinyl It is a group.

R _b11 is an aliphatic hydrocarbon group, a Y ¹³ hydrogen atom or later, the aliphatic hydrocarbon group, a monovalent aliphatic hydrocarbon group having 1 to 8 carbon atoms, excluding aliphatic unsaturated hydrocarbon group , And preferably Y ¹³ described later.

Y ¹¹ , Y ¹² and Y ¹³ are organic groups that can be hydrolyzed, and examples thereof include an alkoxy group having 1 to 6 carbon atoms, an aryloxy group having 6 to 10 carbon atoms, and an acyloxy group having 1 to 4 carbon atoms. The alkoxy group is preferable. Specific examples of the organic group that can be hydrolyzed include methoxy, ethoxy, butoxy, and acyloxy. 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, and more preferably a silane coupling agent in which R _b11 is Y ¹³ and Y ¹¹ , Y ¹² and Y ¹³ are the same as each other. .. More preferably, it is a hydrolyzable silane coupling agent in which at least one of Y ¹¹ , Y ¹² and Y ¹³ is a methoxy group, and particularly preferably, a hydrolyzable silane coupling agent in which all are methoxy groups.

Specific examples of the silane coupling agent having a vinyl group, (meth) acryloyloxy group or (meth) acryloyloxyalkylene group at the end include vinyltrimethoxysilane, vinyltriethoxysilane, vinyltributoxysilane, and vinyldimethoxy. Organosilanes such as ethoxysilane, vinyldimethoxybutoxysilane, vinyldiethoxybutoxysilane, allyltrimethoxysilane, allyltriethoxysilane, vinyltriacetoxysilane, methacryloxypropyltrimethoxysilane, methacryloxypropyltriethoxysilane, methacryloxypropyl Methyldimethoxysilane and the like can be mentioned. These silane coupling agents may be used alone or in combination of two or more. Among such crosslinkable silane coupling agents, a silane coupling agent having a vinyl group and an alkoxy group at the ends is more preferable, and vinyltrimethoxysilane and vinyltriethoxysilane are particularly preferable.
Those having a glycidyl group at the end are 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, Examples thereof include 2- (3,4-epylcyclohexyl) ethyltrimethoxysilane.

The silane coupling agent may be used as it is or diluted with a solvent or the like.

<Silanol condensation catalyst>
The silanol condensation catalyst has a function of causing a silane coupling agent grafted on a polyolefin resin to undergo a condensation reaction in the presence of water. Based on the action of this silanol condensation catalyst, the polyolefin resins are crosslinked with each other via a silane coupling agent. As a result, a heat-resistant silane crosslinked resin molded product having excellent heat resistance can be obtained.

As the silanol condensation catalyst, an organic tin compound, a metal soap, a platinum compound and the like are used. Common silanol condensation catalysts include, for example, dibutyltin dilaurylate, dioctyltin dilaurylate, dibutyltin dioctate, dibutyltin diacetate, zinc stearate, lead stearate, barium stearate, calcium stearate, sodium stearate, etc. Lead naphthenate, lead sulfate, zinc sulfate, organic platinum compounds and the like are used. Among these, organic tin compounds such as dibutyltin dilaurylate, dioctyltin dilaurylate, dibutyltin dioctate, and dibutyltin diacetate are particularly preferable.

<Carrier resin>
The silanol condensation catalyst is used, if desired, mixed with a resin. Such a resin (also referred to as a carrier resin) is not particularly limited, and examples thereof include resins similar to polyolefin resins. As the carrier resin, a part of the above-mentioned polyolefin resin can also be used. A resin made of polyethylene is preferable because it has a good affinity with a silanol condensation catalyst and is also excellent in heat resistance.

<Additives>
The heat-resistant silane cross-linked resin molded body and the heat-resistant silane cross-linked resin composition include various additives generally used in electric wires, electric cables, electric cords, sheets, foams, tubes, and pipes. It may be appropriately blended as long as it does not impair the purpose of. Examples of such additives include cross-linking aids, antioxidants, lubricants, metal deactivators, fillers, other resins and the like.
These additives, particularly antioxidants and metal deactivators, may be mixed with any of the components, but should be added to the carrier resin. It is preferable that the cross-linking aid is substantially free. In particular, it is preferable that the cross-linking aid is not substantially mixed in the step (a) of preparing the silane masterbatch. If the cross-linking aid is not substantially mixed, the polyolefin resins are less likely to be cross-linked during kneading, and the heat-resistant silane cross-linked resin molded product is excellent in appearance and heat resistance. Here, substantially not contained or not mixed means that the cross-linking aid is not positively added or mixed, and does not exclude that it is unavoidably contained or mixed.

The cross-linking aid refers to a compound that forms a partially cross-linked structure with a polyolefin resin in the presence of an organic peroxide. For example, methacrylate compounds such as polypropylene glycol diacrylate and trimethylolpropane triacrylate, allyl compounds such as triallyl cyanurate, and polyfunctional compounds such as maleimide compounds and divinyl compounds can be mentioned.

Antioxidants include, for example, amine antioxidants such as 4,4'-dioctyldiphenylamine, N, N'-diphenyl-p-phenylenediamine, and polymers of 2,2,4-trimethyl-1,2-dihydroquinolin. Agents, pentaerythrityl-tetrakis (3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate), octadecyl-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate , 1,3,5-trimethyl-2,4,6-tris (3,5-di-t-butyl-4-hydroxybenzyl) Phenolic antioxidants such as benzene, bis (2-methyl-4- (3) -N-alkylthiopropionyloxy) -5-t-butylphenyl) sulfide, 2-mercaptobenzidine and zinc salts thereof, sulfur antioxidants such as pentaerythritol-tetrakis (3-lauryl-thiopropionate), etc. Can be mentioned. 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 polyolefin resin.

Examples of the lubricant include hydrocarbons, siloxanes, fatty acids, fatty acid amides, esters, alcohols, metal soaps and the like. These lubricants should be added to the carrier resin (E).

Examples of the metal deactivator include N, N'-bis (3- (3,5-di-t-butyl-4-hydroxyphenyl) propionyl) hydrazine and 3- (N-salicyloyl) amino-1,2,4. -Triazole, 2,2'-oxamidbis- (ethyl 3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate) and the like can be mentioned.

Examples of the filler (including the flame retardant (auxiliary) agent) include fillers other than the above-mentioned various fillers.

Next, the production method of the present invention will be specifically described.
In the production method of the present invention, the step (a) includes 0.01 parts by mass or more and 0.6 parts by mass or less of the organic peroxide and 10 parts by mass or more and 400 parts by mass or less of the inorganic filler with respect to 100 parts by mass of the polyolefin resin. , 4 parts by mass or more of the silane coupling agent and 15.0 parts by mass or less are melt-kneaded at a temperature equal to or higher than the decomposition temperature of the organic peroxide. This prepares a silane masterbatch.

The mixing amount of the organic peroxide is 0.01 to 0.6 parts by mass, preferably 0.1 to 0.5 parts by mass, based on 100 parts by mass of the polyolefin resin. If the mixing amount of the organic peroxide is less than 0.01 parts by mass, the crosslinking reaction does not proceed at the time of crosslinking, and the silane coupling agents are condensed with each other to obtain sufficient heat resistance, mechanical strength, and reinforcing property. May not be possible. On the other hand, if it exceeds 0.6 parts by mass, most of the polyolefin resin is directly crosslinked by the side reaction, which may cause lumps. That is, by setting the mixing amount of the organic peroxide within this range, the polymerization can be carried out in an appropriate range, and the extrudability is excellent without the generation of agglomerates (lumps) due to the crosslinked gel or the like. The composition can be obtained.

The mixing amount of the inorganic filler is 10 to 400 parts by mass, preferably 30 to 280 parts by mass, with respect to 100 parts by mass of the polyolefin resin. If the mixing amount of the inorganic filler is less than 10 parts by mass, the graft reaction of the silane coupling agent may be non-uniform, and the desired heat resistance may not be obtained, or the appearance may be deteriorated due to the non-uniform reaction. On the other hand, if it exceeds 400 parts by mass, the load at the time of molding or kneading becomes very large, and the secondary molding may become difficult.

The mixed amount of the silane coupling agent is more than 4.0 parts by mass and 15.0 parts by mass or less, preferably 6 to 15.0 parts by mass, with respect to 100 parts by mass of the polyolefin resin.
When the mixed amount of the silane coupling agent is 4.0 parts by mass or less, when molding with the silanol condensation catalyst, when the extruder is stopped or the rotation speed of the extruder is significantly changed by adjustment etc. It may occur frequently and cause poor appearance. On the other hand, if it exceeds 15.0 parts by mass, the silane coupling agent cannot be completely adsorbed on the surface of the inorganic filler, and the silane coupling agent volatilizes during kneading, which is uneconomical. In addition, the silane coupling agent that does not adsorb may condense, causing crosslinked gels and burns on the molded product, resulting in deterioration of the appearance.

As described above, when the amount of the silane coupling agent used exceeds 4.0 parts by mass and is 15.0 parts by mass or less, the appearance is excellent. The details of the mechanism are not yet clear, but it can be considered as follows.
That is, in step (a), the reaction due to organic peroxide decomposition when the silane coupling agent silane grafts onto the polyolefin resin is a graft reaction between the silane coupling agent and the polyolefin resin, which has a high reaction rate, or the silane coupling agent. The condensation reaction between them becomes dominant. Therefore, the cross-linking reaction between the polyolefin resins, which causes rough appearance and uneven appearance, is very unlikely to occur. In this way, the cross-linking reaction between the polyolefin resins is effectively suppressed by the mixing amount of the silane coupling agent. As a result, the appearance at the time of molding is improved. Further, since the above-mentioned defects due to the cross-linking reaction between the polyolefin resins are reduced, the appearance defect is less likely to occur even if the extruder is stopped. As a result, it is possible to produce a silane crosslinked resin molded product having a good appearance by suppressing the crosslinking reaction between the polyolefin resins.
On the other hand, in the step (a), many silane coupling agents are bonded to and immobilized on the inorganic filler. Therefore, the condensation reaction between the silane coupling agents bonded to the inorganic filler is unlikely to occur. In addition, it does not bind to the inorganic filler, and the condensation reaction between the free silane coupling agents hardly occurs, and the generation of gels due to the condensation reaction between the free silane coupling agents can be suppressed.
In this way, by using a specific amount of the silane coupling agent, both the cross-linking reaction between the polyolefin resins and the condensation reaction between the silane coupling agents can be suppressed, and the silane-crosslinked resin molded product has a beautiful appearance. It is believed that can be manufactured.

In the step (a), the kneading temperature at which the above-mentioned components are melt-mixed is equal to or higher than the decomposition temperature of the organic peroxide, preferably the decomposition temperature of the organic peroxide + (25 to 110) ° C. This decomposition temperature is preferably set after the polyolefin resin has melted. In addition, kneading conditions such as kneading time can be appropriately set. If the mixture is kneaded at a temperature lower than the decomposition temperature of the organic peroxide, the graft reaction of the silane coupling agent does not occur and the desired heat resistance cannot be obtained, and the organic peroxide reacts during extrusion. Therefore, it may not be possible to mold into a desired shape.

As the kneading method, any method usually used for rubber, plastic and the like can be satisfactorily used, and the kneading device is appropriately selected according to, for example, the mixing amount of the inorganic filler. A single-screw extruder, a twin-screw extruder, a roll, a Banbury mixer or various kneaders are used as the kneading device, and a closed mixer such as a Banbury mixer or various kneaders is used to determine the dispersibility of the polyolefin resin and the stability of the crosslinking reaction. It is preferable in terms of surface.
In addition, when such an inorganic filler is usually mixed in an amount of more than 100 parts by mass with respect to 100 parts by mass of the polyolefin resin, it is preferable to knead the mixture with a continuous kneader, a pressure kneader, or a Banbury mixer.

In the present invention, the mixing order is not specified, and the above components may be mixed in any order as long as the mixing ratio is within the above range. That is, in the step (a), the mixing order is not particularly limited. For example, the above components can be melt-mixed at once.
Preferably, the silane coupling agent is not introduced alone into the silane masterbatch, but is introduced by premixing with an inorganic filler or the like. As a result, the silane coupling agent is less likely to volatilize during kneading, and condensation between the silane coupling agents that are not adsorbed on the inorganic filler can be prevented. Therefore, the appearance is excellent. Further, it is possible to prevent the melting and kneading of the step (a) from becoming difficult. Furthermore, a desired shape can be obtained during extrusion molding.
As such a mixing method, preferably, a mixer-type kneader such as a Banbury mixer or a kneader is used to mix or disperse the organic peroxide, the inorganic filler, and the silane coupling agent at a temperature lower than the decomposition temperature of the organic peroxide. After that, a method of melting and mixing the mixture and the polyolefin resin can be mentioned. By doing so, it is possible to prevent an excessive cross-linking reaction between the polyolefin resins, and the appearance is excellent.

The inorganic filler, the silane coupling agent, and the organic peroxide are mixed at a temperature lower than the decomposition temperature of the organic peroxide, preferably room temperature (25 ° C.). The method of mixing the inorganic filler, the silane coupling agent, and the organic peroxide is not particularly limited, and even if the organic peroxide is mixed at the same time as the inorganic filler or the like, the inorganic filler and the silane coupling agent can be mixed. It may be mixed at any of the mixing steps. Examples of the method for mixing the inorganic filler, the silane coupling agent, and the organic peroxide include a mixing method such as a wet treatment and a dry treatment.

As a method of mixing the inorganic filler and the silane coupling agent, a wet treatment in which the silane coupling agent is added in a state where the inorganic filler is dispersed in a solvent such as water, a dry treatment in which both are added and mixed with or without heating, And both. In the present invention, a dry treatment is preferable in which a silane coupling agent is added to and mixed with an inorganic filler, preferably a dried inorganic filler, with or without heating.
In the above-mentioned wet mixing, the silane coupling agent is likely to be strongly bonded to the inorganic filler, so that the subsequent silanol condensation reaction may be difficult to proceed. On the other hand, in the dry mixing, the bond between the inorganic filler and the silane coupling agent is relatively weak, so that the silanol condensation reaction can easily proceed efficiently.

The silane coupling agent added to the inorganic filler exists so as to surround the surface of the inorganic filler, and a part or all of the silane coupling agent may be adsorbed on the inorganic filler or form a chemical bond with the surface of the inorganic filler. In such a state, the volatilization of the silane coupling agent during the subsequent kneading process with a kneader or a Banbury mixer or the like is significantly reduced, and the unsaturated group of the silane coupling agent is reduced by the organic peroxide. It is considered to undergo a cross-linking reaction with the polyolefin resin. Further, it is considered that the silane coupling agents undergo a condensation reaction with each other by the silanol condensation catalyst during molding. The mechanism of this reaction is not clear, but if the bond between the inorganic filler and the silane coupling agent is too strong during the condensation reaction, the silane coupling agent bound to the inorganic filler will be removed from the inorganic filler even if a silanol condensation catalyst is added. It is considered that the silanol condensation reaction (cross-linking reaction) does not proceed easily.

In the step (a), the organic peroxide may be mixed with the silane coupling agent and then dispersed in the inorganic filler, or may be separated from the silane coupling agent and dispersed in the inorganic filler separately. In the present invention, the organic peroxide and the silane coupling agent should be mixed substantially together.
In the present invention, depending on the production conditions, only the silane coupling agent may be mixed with the inorganic filler, and then the organic peroxide may be added. That is, in the step (a), the inorganic filler that is premixed with the silane coupling agent can be used. As a method of adding the organic peroxide, it may be dispersed in a polyolefin resin, it may be added alone, it may be dispersed in an oil or the like, and it is preferably added dispersed in a polyolefin resin.

In a preferred mixing method, the mixture of the inorganic filler, the silane coupling agent and the organic peroxide and the polyolefin resin are then melt-kneaded while being heated above the decomposition temperature of the organic peroxide to obtain a silane masterbatch. Prepare.

No silanol condensation catalyst is used in step (a). That is, in step (a), each of the above-mentioned components is kneaded without substantially mixing the silanol condensation catalyst. As a result, the silane coupling agent can be easily melt-mixed without condensation, and a desired shape can be obtained during extrusion molding. Here, "substantially not mixed" does not exclude the silanol condensation catalyst that is inevitably present, and exists to the extent that the above-mentioned problem due to silanol condensation of the silane coupling agent does not occur. It means that it is also good.

In this way, step (a) is performed to prepare a silane masterbatch.

The silane masterbatch prepared in the step (a) contains a decomposition product of an organic peroxide, a polyolefin resin, an inorganic filler and a reaction mixture of a silane coupling agent, and can be molded by the step (b) described later. The silane coupling agent contains two types of silane crosslinkable resins (silane graft polymers) grafted on the polyolefin resin.

In the production method of the present invention, the step (b) of mixing the silane masterbatch and the silanol condensation catalyst to obtain a mixture is then performed.
The mixing method may be any mixing method as long as a uniform mixture can be obtained as described above. For example, pellets such as dry blend may be mixed at room temperature or high temperature and introduced into a molding machine, or may be mixed, melt-mixed, pelletized again, and introduced into a molding machine.
In any of the mixings, in order to avoid the silanol condensation reaction, it is preferable that the silane masterbatch and the silanol condensation catalyst are not kept in a high temperature state for a long time in a mixed state. The resulting mixture is a mixture that retains at least the moldability in molding in step (c).

In step (b), the silanol condensation catalyst is preferably used with the carrier resin. That is, the step (b) may be a step of mixing the silane masterbatch and the silanol condensation catalyst, and a step of melt-mixing the catalyst masterbatch containing the silanol condensation catalyst and the carrier resin and the silane masterbatch is preferable. Therefore, preferably, in carrying out the step (b), the carrier resin and the silanol condensation catalyst are melt-mixed to prepare a catalyst masterbatch.
The mixing ratio of the carrier resin and the silanol condensation catalyst in the catalyst masterbatch is set so as to satisfy the mixing ratio of the silane masterbatch with the polyolefin resin in the step (b) described later.
The mixing of the carrier resin and the silanol condensation catalyst is appropriately determined according to the melting temperature of the carrier resin. For example, the kneading temperature can be 80 to 250 ° C., more preferably 100 to 240 ° C. The kneading conditions such as the kneading time can be set as appropriate. The kneading method can be carried out in the same manner as the above-mentioned kneading method.

The catalyst masterbatch thus prepared is a mixture of silanol condensation catalyst, carrier resin and optionally added filler.

In the step (b), the blending amount of the silanol condensation catalyst is preferably 0.0001 to 0.5 parts by mass, and more preferably 0.001 to 0.1 parts by mass with respect to 100 parts by mass of the polyolefin resin. When the mixing amount of the silanol condensation catalyst is within the above range, the cross-linking reaction due to the condensation reaction of the silane coupling agent tends to proceed almost uniformly, and the heat-resistant silane cross-linked resin molded product is excellent in heat resistance, appearance and physical properties, and is produced. The sex is also improved.
When the catalyst masterbatch is mixed, the blending amount of the carrier 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 polyolefin resin. Is. Further, an inorganic filler may or may not be added to this carrier resin. The amount of the inorganic filler at that time is not particularly limited, but is preferably 350 parts by mass or less with respect to 100 parts by mass of the polyolefin resin of the carrier resin. This is because if the amount of filler is too large, the silanol condensation catalyst is difficult to disperse and cross-linking is difficult to proceed. On the other hand, if the amount of the carrier resin is too large, the degree of cross-linking of the molded product is lowered, and there is a possibility that appropriate heat resistance cannot be obtained.

In step (b), the mixing conditions of the silane masterbatch and the silanol condensation catalyst or the catalyst masterbatch are appropriately selected. That is, when the silanol condensation catalyst is mixed alone in the silane masterbatch, the mixing conditions are set to appropriate melt mixing conditions according to the polyolefin resin.

On the other hand, when the catalyst masterbatch containing the silanol condensation catalyst is mixed with the silane masterbatch, melt mixing is preferable in terms of dispersion of the silanol condensation catalyst, which is basically the same as the melt mixing in step (1). Although some polyolefin resins, such as elastomers, whose melting point cannot be measured by DSC or the like, are kneaded at a temperature at which at least one of the polyolefin resin and the organic peroxide melts. The melting temperature is appropriately selected according to the melting temperature of the carrier resin, and is, for example, preferably 80 to 250 ° C., more preferably 100 to 240 ° C. The kneading conditions such as the kneading time can be set as appropriate.

In this way, the steps (a) and (b) of the present invention, that is, the method for producing the heat-resistant silane crosslinkable resin composition of the present invention are carried out, and at least two different silanes having different crosslinking methods will be described later. A heat-resistant silane crosslinkable resin composition containing a crosslinkable resin is produced. Therefore, the heat-resistant silane crosslinkable resin composition of the present invention is a composition obtained by carrying out steps (a) and (b), and is a mixture of a silane masterbatch and a silanol condensation catalyst or a catalyst masterbatch. It is considered to be a thing. Its components are basically the same as the silane masterbatch and silanol condensation catalyst or catalyst masterbatch.

The method for producing the heat-resistant silane crosslinked resin molded product of the present invention is then carried out in steps (c) and (d). That is, in the method for producing a heat-resistant silane-crosslinked resin molded product of the present invention, the step (c) of molding the obtained mixture, that is, the heat-resistant silane-crosslinked resin composition of the present invention to obtain a molded product is performed. In this step (c), it is sufficient that the mixture can be molded, and the molding method and molding conditions are appropriately selected according to the form of the heat-resistant product of the present invention. For example, when the heat-resistant product of the present invention is an electric wire or an optical fiber cable, extrusion molding or the like is selected.

In step (c), the operation of the extruder can be temporarily stopped and then restarted without any problem due to reasons such as cleaning of the extruder, step change, eccentricity adjustment, and interruption of production. Here, once stopped and then restarted depends on the composition of the thermosetting silane crosslinkable resin composition, processing conditions, etc., and cannot be unambiguously stated, but for example, at intervals of up to 5 minutes, preferably up to 10 minutes. More preferably, it means that it can be stopped for up to 15 minutes. The temperature at this time is not particularly limited as long as it is a temperature at which the polyolefin resin softens or melts, and is, for example, 200 ° C.

Further, the step (c) can be carried out simultaneously with or continuously of the step (b). For example, a series of steps can be adopted in which the silane masterbatch and the silanol condensation catalyst (C) or the catalyst masterbatch are melt-kneaded in a coating device, and then coated on, for example, an extruded electric wire or fiber to form a desired shape.

In this way, the heat-resistant silane crosslinkable resin composition of the present invention is molded, and the molded body of the heat-resistant silane crosslinkable resin composition obtained in steps (a) to (c) is an uncrosslinked body. Therefore, the heat-resistant silane crosslinked resin molded article of the present invention is obtained by carrying out the following step (d) after the step (c) to obtain a crosslinked or finally crosslinked molded article.

In the method for producing a heat-resistant silane crosslinked resin molded article of the present invention, a step of bringing the molded article (uncrosslinked article) obtained in step (c) into contact with water is performed. As a result, the hydrolyzable group of the silane coupling agent is hydrolyzed to silanol, and the silanol condensation catalyst present in the resin condenses the hydroxyl groups of silanol to cause a cross-linking reaction, so that the molded product is crosslinked. A sexilane crosslinked resin molded product can be obtained. The process itself of this step (d) can be performed by a usual method. By bringing water into contact with the molded product, the hydrolyzable groups of the silane coupling agent are hydrolyzed and the silane coupling agents are condensed with each other to form a crosslinked structure.

Condensation between silane coupling agents proceeds only by storing at room temperature. Therefore, in step (d), it is not necessary to positively contact the molded product (uncrosslinked product) with water. It can also be contacted with moisture to further accelerate the cross-linking. For example, a method of actively contacting with water such as immersion in hot water, charging into a moist heat tank, and exposure to high-temperature steam can be adopted. Further, at that time, pressure may be applied to allow water to permeate into the inside.

In this way, the method for producing the heat-resistant silane-crosslinked resin molded product of the present invention is carried out, and the heat-resistant silane-crosslinked resin molded product is produced from the heat-resistant silane-crosslinked resin composition of the present invention. Therefore, the heat-resistant silane crosslinked resin molded product of the present invention is a molded product obtained by carrying out steps (a) to (d). Then, as will be described later, this molded product contains a polyolefin resin formed by cross-linking with an inorganic filler via a silanol bond.

The details of the reaction mechanism in the production method of the present invention have not been clarified yet, but it is considered as follows. That is, when the polyolefin resin is heated and kneaded together with the inorganic filler and the silane coupling agent at a temperature equal to or higher than the decomposition temperature of the organic peroxide in the presence of the organic peroxide component, the organic peroxide decomposes to generate radicals, and the polyolefin resin On the other hand, grafting occurs with a silane coupling agent. In addition, the heating at this time partially promotes the formation reaction of a chemical bond by a covalent bond between the silane coupling agent and a group such as a hydroxyl group on the surface of the inorganic filler.
In the present invention, the final cross-linking reaction may be carried out in the step (d), and when a specific amount of the silane coupling agent is added to the polyolefin resin as described above, the inorganic filler does not impair the extrudability during molding. Can be blended in a large amount, and can have heat resistance, mechanical properties, etc. while ensuring excellent flame retardancy.

The mechanism of action of the above process of the present invention is not yet clear, but is presumed as follows. That is, by using the inorganic filler and the silane coupling agent before and / or during kneading with the polyolefin resin, the silane coupling agent is bonded to the inorganic filler by an alkoxy group, and vinyl existing at the other end is bonded. It is physically and chemically adsorbed and retained on the holes and surfaces of the inorganic filler without being bonded to the uncrosslinked portion of the polyolefin resin by an ethylenically unsaturated group such as a group or not bonded to the inorganic filler. In this way, a silane coupling agent that binds to the inorganic filler with a strong bond (for example, the formation of a chemical bond with a hydroxyl group on the surface of the inorganic filler is considered) and a silane coupling agent that binds to the inorganic filler with a weak bond (the reason is considered). The reason may be, for example, an interaction due to hydrogen bonds, an interaction between ions, partial charges or dipoles, an action due to adsorption, etc.). In this state, when an organic peroxide is added and kneaded with the polyolefin resin, at least two kinds of silane crosslinkable resins having different bonds with the inorganic filler and having a graft reaction of the silane coupling agent with the polyolefin resin are formed. To.

By the above-mentioned kneading, among the silane coupling agents, the silane coupling agent having a strong bond with the inorganic filler has an ethylenically unsaturated group as a cross-linking group and a graft reaction with the cross-linked portion of the polyolefin resin. In particular, when a plurality of silane coupling agents are bonded to the surface of one inorganic filler particle via a strong bond, a plurality of polyolefin resins are bonded via the inorganic filler particles. These reactions or bonds expand the cross-linking network through the inorganic filler.
In the case of a silane coupling agent having a strong bond with the inorganic filler, the condensation reaction with the silanol condensation catalyst in the presence of water is unlikely to occur, and the bond with the inorganic filler is maintained. Therefore, the polyolefin resin and the inorganic filler are bonded, and the polyolefin resin is crosslinked through the inorganic filler. As a result, the adhesion between the polyolefin resin and the inorganic filler is strengthened, mechanical strength and wear resistance are good, and a molded product that is not easily scratched can be obtained.

On the other hand, among the silane coupling agents, the silane coupling agent having a weak bond with the inorganic filler is separated from the surface of the inorganic filler, and the ethylenically unsaturated group which is the cross-linking group of the silane coupling agent is a polyolefin resin. A graft reaction occurs by reacting with a resin radical generated by abstraction of hydrogen radicals by radicals generated by decomposition of organic peroxide. The silane coupling agent of the graft portion thus produced is subsequently mixed with a silanol condensation catalyst and brought into contact with water to cause a condensation reaction (crosslinking reaction).

In particular, in the present invention, the cross-linking reaction by condensation using a silanol condensation catalyst in the presence of water in this step (d) is performed after forming the molded product. As a result, the workability in the process up to the formation of the molded body is excellent as compared with the conventional method of forming the molded body after the final cross-linking reaction. Further, a plurality of silane coupling agents can be bonded to the surface of one inorganic filler particle, which makes it possible to obtain higher heat resistance than before and also to obtain high mechanical strength.

In this way, when the silane crosslinkable resin obtained by graft-reacting the silane coupling agent with a strong bond to the inorganic filler with the polyolefin resin comes into contact with water, it becomes the inorganic filler via the silanol bond of the silane coupling agent. A crosslinked silane crosslinked polyolefin resin is formed. A silane coupling agent bonded to an inorganic filler with a strong bond is considered to contribute to high mechanical properties, wear resistance, scratch resistance, etc. in some cases.
Further, when the silane crosslinkable resin obtained by grafting the silane coupling agent bonded to the inorganic filler with a weak bond to the polyolefin resin comes into contact with water, the polyolefin resins are crosslinked via the silanol bond of the silane coupling agent. A silane crosslinked polyolefin resin is formed. The silane coupling agent bonded to the inorganic filler with a weak bond is considered to contribute to the improvement of the degree of cross-linking, that is, the improvement of heat resistance.

In particular, in the present invention, a silane coupling agent of more than 4.0 parts by mass and 15.0 parts by mass or less is mixed with the inorganic filler, and as described above, the polyolefin during melt-kneading in the step (a). The cross-linking reaction between resins can be effectively suppressed. In addition, the silane coupling agent is bonded to the inorganic filler to varying degrees, and is less likely to volatilize during melt-kneading in step (a), and the reaction between the liberated silane coupling agents is also effective. Can be suppressed. Therefore, it is considered that even if the extruder is stopped, poor appearance is unlikely to occur, and a silane crosslinked resin molded product having a good appearance can be produced.

The manufacturing method of the present invention can be applied to the manufacture of components of products such as products requiring heat resistance (including semi-finished products, parts and members), products requiring strength, rubber materials, or members thereof. .. Examples of such products include electric wires such as heat-resistant and flame-retardant insulated wires, heat-resistant and flame-retardant cable coating materials, rubber substitute electric wires and cable materials, other heat-resistant and flame-retardant electric wire parts, flame-retardant heat-resistant sheets, and flame-retardant heat-resistant films. Can be mentioned. It is also used in the manufacture of power plugs, connectors, sleeves, boxes, tape substrates, tubes, seats, packings, cushioning materials, anti-seismic materials, wiring materials used for internal and external wiring of electrical and electronic equipment, especially electric wires and optical cables. Can be applied. Among the components and the like of the above-mentioned products, the manufacturing method of the present invention is particularly preferably applied to the manufacturing of insulators, sheaths and the like of electric wires and optical cables, and can be formed as a coating thereof.
Insulators, sheaths, etc. can be molded into their shapes by coating them while melting and kneading them in an extrusion coating device. Molded products such as insulators and sheaths are general-purpose extrusion coating devices that do not use special machines such as electron beam crosslinkers to crosslink compositions that do not melt at high temperatures with high heat resistance to which a large amount of inorganic filler is added. Can be formed by extruding and coating around a conductor or around a conductor in which tensile strength fibers are vertically attached or twisted. For example, as the conductor, any conductor such as annealed copper single wire or stranded wire can be used. Further, as the conductor, in addition to the bare wire, a conductor plated with tin or having an enamel-coated insulating layer may be used. The wall thickness of the insulating layer (coating layer made of the heat-resistant resin composition of the present invention) formed around the conductor is not particularly limited, but is usually about 0.15 to 5 mm.

Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited thereto. In Tables 1 and 2, the numerical values in each Example , Reference Example and Comparative Example represent parts by mass.

Reference Examples 1 to 18 , Examples 12 and Comparative Examples 1 to 5 were carried out by using the components shown in Tables 1 and 2 and changing their respective specifications or manufacturing conditions.

The following compounds were used as the components shown in Tables 1 and 2.
<Polyolefin resin>
(1) "UE320" (manufactured by Japan Polyethylene Corporation, Novatec PE (trade name), linear low density polyethylene (LLDPE), density 0.92 g / cm ³ )
(2) "Evolu SP1540" (trade name, manufactured by Prime Polymer Co., Ltd., linear metallocene polyethylene (LLDPE))
(3) "EC9" (manufactured by Japan Polypropylene Corporation, Novatec PP (trade name), polypropylene)
(4) "EV360" (trade name, manufactured by Mitsui / DuPont Chemical Co., Ltd., ethylene-vinyl acetate copolymer resin (EVA), VA content: 33% by mass)
(5) "Septon 4077" (trade name, manufactured by Kuraray, styrene elastomer (SEEPS), styrene content 30% by mass)
(6) "Mitsui 3092EPM" (trade name, manufactured by Mitsui Chemicals, ethylene-propylene-diene rubber, ethylene content 66%)
(7) "Admer XE-070" (trade name, manufactured by Mitsui Chemicals, Inc., maleic anhydride-modified ethylene-α-olefin copolymer)
(8) "Diana Process PW90" (trade name, manufactured by Idemitsu Kosan Co., Ltd., paraffin oil)

<Organic peroxide>
"Perhexa 25B" (trade name, manufactured by NOF CORPORATION, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane, decomposition temperature 149 ° C.)
<Inorganic filler>
(1) Magnesium hydroxide (trade name: Kisuma 5, manufactured by Kyowa Chemical Industry Co., Ltd., average particle size 0.8 μm)
(2) Aluminum hydroxide (trade name: Heidilite H42M, manufactured by Showa Denko KK, average particle size 1.2 μm)
(3) Calcium carbonate (trade name: Softon 1200, manufactured by Bikita Powder Co., Ltd., average particle size 1.5 μm)
(4) Antimony trioxide (trade name: PATOX-C, manufactured by Nihon Seiko Co., Ltd., average particle size 3.5 μm)
(5) Silica (trade name: Crystallite 5X, manufactured by Ryumori Co., Ltd., average particle size 1.2 μm)

<Silane coupling agent>
"KBM-1003" (trade name, manufactured by Shin-Etsu Chemical Co., Ltd., vinyltrimethoxysilane)
"KBE-1003" (trade name, manufactured by Shin-Etsu Chemical Co., Ltd., vinyltriethoxysilane)
<Carrier resin>
The above-mentioned "UE320" (product name)
<Silanol condensation catalyst>
"ADEKA STUB OT-1" (trade name, manufactured by ADEKA, Dioctyl tin laurilate)
<Antioxidant (hindered phenol antioxidant)>
"Irganox 1010" (trade name, manufactured by Nagase & Co., Ltd., pentaerythritol tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate])

( Reference Examples 1 to 15 , Examples 12 and Comparative Examples 1 to 5)
First, the organic peroxide, the inorganic filler and the silane coupling agent are put into a 10L Henschel mixer manufactured by Toyo Seiki Co., Ltd. at the mass ratio shown in Table 1 and mixed at room temperature (25 ° C.) for 1 hour to prepare a powder mixture. Got
Next, the powder mixture thus obtained and the polyolefin resin were put into a 2L Banbury mixer manufactured by Nippon Roll in the mass ratio shown in Table 1 to exceed the decomposition temperature of the organic peroxide (P). After kneading at a temperature, specifically 180 to 190 ° C. for about 12 minutes, the material was discharged at a material discharge temperature of 180 to 190 ° C. to obtain a silane masterbatch (also referred to as silane MB) (step (a)). The obtained silane MB contains at least two types of silane crosslinkable resins in which a silane coupling agent is graft-reacted with an olefin resin.

On the other hand, the carrier resin "UE320", the silanol condensation catalyst, and the antioxidant are separately melt-mixed with a Banbury mixer at 180 to 190 ° C. at the mass ratio shown in Table 1 and discharged at a material discharge temperature of 180 to 190 ° C. , A catalyst masterbatch (also referred to as catalyst MB) was obtained. This catalyst masterbatch is a mixture of carrier resin, silanol condensation catalyst and antioxidant. Next, the silane MB and the catalyst MB are melted at 180 ° C. by a Banbury mixer at a mass ratio shown in Table 1, that is, a ratio of 100 parts by mass of the polyolefin resin of silane SM and 5 parts by mass of the carrier resin of the catalyst MB. Mixed (step (b)).
In this way, a heat-resistant silane crosslinkable resin composition was prepared. This heat-resistant silane crosslinkable resin composition is a mixture of silane MB and catalyst MB, and contains at least two of the above-mentioned silane crosslinkable resins.

Next, this heat-resistant silane crosslinkable resin composition was introduced into a 40 mm extruder with L / D = 24 (compressor screw temperature 190 ° C., head temperature 200 ° C.), and the wall thickness was outside the 1 / 0.8TA conductor. A wire (uncrosslinked) having an outer diameter of 2.8 mm was obtained by coating with 1 mm (step (c)).

The obtained electric wire (uncrosslinked) was left in an atmosphere of a temperature of 80 ° C. and a humidity of 95% for 24 hours (step (d)).
In this way, an electric wire having a coating made of a heat-resistant silane crosslinked resin molded body was manufactured.
As described above, this heat-resistant silane crosslinked resin molded product contains the above-mentioned silane crosslinked resin in which the silane crosslinkable resin is crosslinked by the condensation reaction of hydrolyzable groups of the silane coupling agent.

( Reference example 16)
Each component shown in Table 2 was used in the mass ratio (parts by mass) shown in the same table, and a silane MB (step (a)) and a catalyst MB were prepared in the same manner as in Reference Example 1 above.
Next, the obtained silane MB and catalyst MB were put into a closed ribbon blender and dry-blended at room temperature (25 ° C.) for 5 minutes to obtain a dry-blended product. At this time, the mixing ratio of the silane MB and the catalyst MB was 100 parts by mass of the polyolefin resin of the silane SM and 5 parts by mass of the carrier resin of the catalyst MB (see Table 2). Next, this dry blend is put into a 40 mm extruder with L / D = 24 (compressor screw temperature 190 ° C., head temperature 200 ° C.), and 1 / 0.8TA is melt-mixed in the extruder screw. The outside of the conductor was coated with a wall thickness of 1 mm to obtain an electric wire (uncrosslinked) having an outer diameter of 2.8 mm (steps (b) and (c)).
The obtained electric wire (uncrosslinked) was left in an atmosphere having a temperature of 80 ° C. and a humidity of 95% for 24 hours (step (d)).
In this way, an electric wire having a coating made of a heat-resistant silane crosslinked resin molded body was manufactured.

( Reference example 17)
An electric wire (outer diameter 2.) in which each component shown in Table 2 is used in the mass ratio (part by mass) shown in the same table, and the outer circumference of the conductor is coated with a heat-resistant silane crosslinkable resin composition in the same manner as in Reference Example 1 above. 8 mm, uncrosslinked) was obtained (step (a), step (b) and step (c)).
The obtained electric wire was left in an atmosphere having a temperature of 23 ° C. and a humidity of 50% for 72 hours (step (d)).
In this way, an electric wire having a coating made of a heat-resistant silane crosslinked resin molded body was manufactured.

( Reference example 18)
Each component shown in Table 2 was used in the mass ratio (parts by mass) shown in the same table to prepare a silane MB in the same manner as in Reference Example 1 above (step (a)).
On the other hand, the carrier resin "UE320", the silanol condensation catalyst and the antioxidant were melt-mixed by a twin-screw extruder at the mass ratios shown in Table 2 to obtain a catalyst MB. The screw diameter of the twin-screw extruder was set to 35 mm, and the cylinder temperature was set to 180 to 190 ° C. The obtained catalyst MB is a mixture of a carrier resin, a silanol condensation catalyst, and an antioxidant.
Then, the obtained silane MB and the catalyst MB were melt-mixed at 180 ° C. by a Banbury mixer (step (b)). The mixing ratio of the silane MB and the catalyst MB was 100 parts by mass of the polyolefin resin of the silane SM and 5 parts by mass of the carrier resin of the catalyst MB (see Table 2). In this way, a heat-resistant silane crosslinkable resin composition was prepared. This heat-resistant silane crosslinkable resin composition is a mixture of silane MB and catalyst MB, and contains at least two of the above-mentioned silane crosslinkable resins.
Next, this heat-resistant silane crosslinkable resin composition was introduced into a 40 mm extruder with L / D = 24 (compressor screw temperature 190 ° C., head temperature 200 ° C.), and the wall thickness was outside the 1 / 0.8TA conductor. A wire (uncrosslinked) having an outer diameter of 2.8 mm was obtained by coating with 1 mm (step (c)).
The obtained electric wire (uncrosslinked) was left in a state of being immersed in warm water having a temperature of 50 ° C. for 10 hours (step (d)).
In this way, an electric wire having a coating made of a heat-resistant silane crosslinked resin molded body was manufactured.

The following evaluations were made for the manufactured electric wires, and the results are shown in Tables 1 and 2.

<Mechanical characteristics>
A tensile test was performed as a mechanical property of the electric wire.
This tensile test was performed according to JIS C 3005. Tensile strength (MPa) and tensile elongation (%) were measured using a tubular piece of electric wire from which a conductor was extracted from the electric wire, with a distance between marked lines of 25 mm and a tensile speed of 500 mm / min.
Those with a tensile strength of 8 MPa or more are accepted, and those with a tensile elongation of 100% or more are accepted.

<Heat deformation test>
A heat deformation test was conducted to determine the heat resistance of the electric wire.
The heat deformation test was performed at a measurement temperature of 150 ° C. and a load of 5 N based on UL1581. In addition, the measured value of 50% or less was regarded as acceptable.

<Hot set test>
A hot set test was conducted as the heat resistance of the electric wire.
In the hot set test 1, a tubular piece of an electric wire was prepared, a wire with a length of 50 mm was attached, and then a weight of 117 g was placed in a constant temperature bath at 170 ° C. and left for 15 minutes, and the length after leaving was measured. Then, the elongation rate was determined (hot set test 1).
Next, the elongation rate was determined by measuring the length after leaving the load after removing the load (hot set test 2).
The hot set test 1 passed the elongation rate of 100% or less, and the hot set test 2 passed the elongation rate of 80% or less.

<Extruded appearance characteristics of electric wires>
Extrusion appearance test 1 was performed as an extrusion appearance characteristic of the electric wire.
The extruded appearance test 1 was evaluated by observing the extruded appearance when manufacturing the electric wire. Specifically, when extruded with a 65 mm extruder at a linear speed of 50 m / min, the wire with a good appearance is "A", the one with a slightly bad appearance is "B", and the one with a significantly bad appearance. Was regarded as "C", and "B" or higher was regarded as a product level and passed.

As an extrusion appearance characteristic of the electric wire, an extrusion appearance test 2 was performed in which the extruder was stopped and then restarted.
For the extruded appearance 2, when manufacturing the electric wire, the linear speed is set to 50 m / min with a 65 mm extruder to manufacture the electric wire, the extruder is stopped once in the middle, and 10 minutes later, the extruder is restarted under the same conditions. It was evaluated by operating it to manufacture electric wires and observing the appearance of the manufactured electric wires. Specifically, the wire speed was set to 50 m / min again, the extruder was restarted, and the appearance of the extruded electric wire was observed 5 minutes later.
The evaluation was "A" when the wire speed was set to 50 m / min again and then observed 5 minutes later, the wire appearance was good and the number of lumps was within 2 per 1 m, and the appearance was slightly bad. Alternatively, 3 to 10 lumps are confirmed in 1 m as "B", the appearance is remarkably bad, or 11 or more lumps are confirmed in 1 m as "C", and "B" or more is defined as "B" or more. Passed as a product level.

As is clear from the results of Tables 1 and 2, both Reference Examples 1 to 18 and Example 12 have passed the extrusion appearance test 2, and even if the extruder is stopped and then restarted, the appearance is rough. We were able to manufacture an electric wire with excellent appearance and less lumps. In particular, in Reference Examples 1 to 4, 6 to 10, 13, 14 , 16 to 18 and Example 12 in which 6 parts by mass or more of the silane coupling agent was used with respect to the polyolefin resin, the lumps were 1 m in the extrusion appearance test 2. It was possible to manufacture an electric wire having more excellent appearance characteristics, in which only two or less were generated.
Further, in each of Reference Examples 1 to 18 and Example 12 , electric wires having passed the mechanical properties, heat resistance and extruded appearance could be produced.
As described above, the heat-resistant silane crosslinked resin molded product of the present invention provided as the coating of the electric wires of Reference Examples 1 to 18 and Example 12 was excellent in appearance even when the extruder was stopped and then restarted. Moreover, it was excellent in all of mechanical properties, heat resistance and appearance. It can be easily understood that the flame retardancy is excellent from the mixed amount of the inorganic filler.

On the other hand, Comparative Examples 1 and 2 in which the amount of the silane coupling agent used was small passed the extrusion appearance test 1, but failed the extrusion appearance test 2. On the other hand, Comparative Example 3 in which the amount of the silane coupling agent used is large is foamed during production and does not pass the extrusion appearance test 1 and the extrusion appearance test 2, and the hot set test 1 fails and is inferior in heat resistance. Was there.
Comparative Example 4 in which the amount of organic peroxide used was small failed the heat deformation test and hot set test 1 and was inferior in heat resistance, and Comparative Example 5 in which the amount of organic peroxide used was large could not even be extruded. ..

Although the present invention has been described with its embodiments, we do not intend to limit our invention in any detail of the description unless otherwise specified, and contrary to the spirit and scope of the invention set forth in the appended claims. I think that it should be widely interpreted without.

The present application claims priority based on Japanese Patent Application No. 2013-175676 filed in Japan on August 27, 2013, which is referred to herein and is described herein. Import as a part.

Claims (13)

0.01 parts by mass or more and 0.6 parts by mass or less of organic peroxide and 10 parts by mass or more and 400 parts by mass or less of inorganic filler with respect to 100 parts by mass of polyolefin resin containing polypropylene and 40% by mass or less of mineral oil softener. , A silane coupling agent having a group capable of graft reaction and a hydrolyzable group. More than 4 parts by mass and 15.0 parts by mass or less are melt-kneaded at a temperature equal to or higher than the decomposition temperature of the organic peroxide to obtain the silane. The step (a) of preparing a silane master batch by grafting the coupling agent with the polyolefin resin, and
The step (b) of mixing the silane masterbatch and the silanol condensation catalyst to obtain a mixture, and
The step (c) of molding the mixture to obtain a molded product,
Wherein the compact method of manufacturing a heat-resistant silane crosslinkable resin molded body have a the step (d) of obtaining a heat resistant silane crosslinked resin molded product into contact with water,
In performing the step (a), the organic peroxide, the inorganic filler, and the silane coupling agent are mixed at a temperature lower than the decomposition temperature of the organic peroxide, and then the obtained mixture and the polyolefin resin are used. Melt and knead,
Wherein the inorganic filler is boron nitride, silica, carbon, clay, zinc oxide, tin oxide, titanium oxide, molybdenum oxide, antimony trioxide, quartz, talc, zinc borate, zinc borate, hydroxy stannate, zinc stannate and At least one selected from the group consisting of calcium carbonate,
A method for producing a heat-resistant silane crosslinked resin molded product. The method for producing a heat-resistant silane crosslinked resin molded product according to claim 1, wherein the mixed amount of the silane coupling agent is 6 parts by mass or more and 15.0 parts by mass or less with respect to 100 parts by mass of the polyolefin resin . The method for producing a heat-resistant silane crosslinked resin molded product according to claim 1 or 2 , wherein the silane coupling agent is vinyltrimethoxysilane or vinyltriethoxysilane . The method for producing a heat-resistant silane crosslinked resin molded product according to any one of claims 1 to 3 , wherein the inorganic filler is at least one selected from the group consisting of silica, calcium carbonate and antimony trioxide . The method for producing a heat-resistant silane crosslinked resin molded product according to any one of claims 1 to 4 , wherein the melt kneading in the step (a) is performed with a closed mixer . The method for producing a heat-resistant silane crosslinked resin molded product according to any one of claims 1 to 5 , wherein the silanol condensation catalyst is not substantially mixed in the step (a) . 0.01 parts by mass or more and 0.6 parts by mass or less of organic peroxide and 10 parts by mass or more and 400 parts by mass or less of inorganic filler with respect to 100 parts by mass of polyolefin resin containing polypropylene and 40% by mass or less of mineral oil softener. , A silane coupling agent having a group capable of graft reaction and a hydrolyzable group. More than 4 parts by mass and 15.0 parts by mass or less are melt-kneaded at a temperature equal to or higher than the decomposition temperature of the organic peroxide to obtain the silane. The step (a) of preparing a silane master batch by grafting the coupling agent with the polyolefin resin, and
A method for producing a thermosetting silane crosslinkable resin composition, which comprises the step (b) of mixing the silane masterbatch and a silanol condensation catalyst to obtain a mixture.
In performing the step (a), the organic peroxide, the inorganic filler, and the silane coupling agent are mixed at a temperature lower than the decomposition temperature of the organic peroxide, and then the obtained mixture and the polyolefin resin are mixed. Melt kneading,
The inorganic fillers include boric acid, silica, carbon, clay, zinc oxide, tin oxide, titanium oxide, molybdenum oxide, antimony trioxide, quartz, talc, zinc borate, zinc borate, zinc hydroxytinate, zinc stannate and At least one selected from the group consisting of calcium carbonate,
A method for producing a thermosetting silane crosslinkable resin composition. A thermosetting silane crosslinkable resin composition produced by the production method according to claim 7. A heat-resistant silane crosslinked resin molded product produced by the production method according to any one of claims 1 to 6. The heat-resistant silane crosslinked resin molded body according to claim 9, wherein the heat-resistant silane crosslinked resin molded body contains the polyolefin resin formed by cross-linking the heat-resistant silane crosslinked resin molded body with the inorganic filler via a silanol bond. A heat-resistant product containing the heat-resistant silane crosslinked resin molded product according to claim 9 or 10. The heat-resistant product according to claim 11, wherein the heat-resistant silane crosslinked resin molded body is provided as a coating for an electric wire or an optical fiber cable. With respect to 100 parts by mass of a polyolefin resin containing polypropylene and 40% by mass or less of a mineral oil softening agent, 0.01 parts by mass or more and 0.6 parts by mass or less of an organic peroxide, zinc oxide, silica, carbon, clay, and oxidation. At least one inorganic filler 10 selected from the group consisting of zinc, tin oxide, titanium oxide, molybdenum oxide, antimony trioxide, quartz, talc, zinc borate, zinc borate, zinc hydroxytinate, zinc stannate and calcium carbonate 10. More than 4 parts by mass and 400 parts by mass or less, and more than 4 parts by mass of a silane coupling agent having a graft-reactive group and a hydrolyzable group and 15.0 parts by mass or less, which is equal to or higher than the decomposition temperature of the organic peroxide. A silane master batch obtained by melt-kneading at a temperature and graft-reacting the silane coupling agent with the polyolefin resin.
The melt-kneading mixes the organic peroxide, the inorganic filler, and the silane coupling agent at a temperature lower than the decomposition temperature of the organic peroxide, and then melt-mixes the obtained mixture and the polyolefin resin. Silane masterbatch performed by smelting.