JP2019116583A - Heat resistant silane crosslinked resin molded body and manufacturing method therefor, and heat resistant product using heat resistant silane crosslinked resin molded body - Google Patents

Abstract

To provide a manufacturing method of a heat resistant silane crosslinked resin molded body capable of manufacturing the heat resistant silane crosslinked resin molded body excellent in appearance without black point due to burn by suppressing volatilization of a silane coupling agent, the heat resistant silane crosslinked resin molded body excellent in appearance without black point due to burn, and a heat resistant product using the same.SOLUTION: There are provided a manufacturing method of a heat resistant silane crosslinked resin molded body having a process (a) for melting and mixing a resin composition containing a polyolefin resin and an inorganic filler at specific amounts, a process (b) for mixing the resulting molten mixed article, organic peroxide and a silane coupling agent at specific amounts, a process (c) for grafting reacting a silane graft resin to a polyolefin resin by melting and mixing the resulting mixture at a decomposition temperature of the organic peroxide, a process (d) for melting and mixing a silane master batch obtained in the process (c) and a silanol condensation catalyst and then molding them, and a process (e) for contacting the resulting molded body and water, a heat resistant silane crosslinked resin molded body and a heat resistant product.SELECTED DRAWING: None

Description

  The present invention relates to a heat-resistant silane-crosslinked resin molded product, a method for producing the same, and a heat-resistant product using the heat-resistant silane-crosslinked resin molded product.

  Flame resistance, heat resistance, mechanical properties (for example, tensile properties, abrasion resistance, etc.) for wiring materials such as insulated wires, cables, cords and optical fiber cores, optical fiber cords, etc. used for the internal and external wiring of electric and electronic devices Characteristics, etc. are required. As materials used for these wiring materials, resin compositions containing a large amount of metal hydrates such as magnesium hydroxide and aluminum hydroxide are used.

Moreover, the wiring material used for an electric and electronic device may heat up to about 80-105 degreeC and also about 125 degreeC when it is used for a long time, and the flame retardance with respect to this may be required. In such a case, for the purpose of imparting high flame retardancy to the wiring material, a method of crosslinking the coating material by an electron beam crosslinking method, a chemical crosslinking method or the like is adopted.
Conventionally, as a method of crosslinking a polyolefin resin such as polyethylene, an electron beam crosslinking method of crosslinking (also referred to as crosslinking) by irradiating an electron beam, and further decomposition of an organic peroxide or the like by applying heat after molding Chemical crosslinking methods such as a crosslinking method which causes a crosslinking reaction and a silane crosslinking method using a hydrolyzable silane coupling agent are known. Among these crosslinking methods, in particular, the silane crosslinking method has a production advantage because it often does not require special equipment.

In the silane crosslinking method, a hydrolyzable silane coupling agent having an unsaturated group is allowed to graft onto a resin in the presence of an organic peroxide to obtain a silane graft resin, and then water is produced in the presence of a silanol condensation catalyst. And a silane coupling agent is subjected to silanol condensation to obtain a crosslinked product of a silane graft resin.
In the silane crosslinking method, usually, components such as a resin, a hydrolyzable silane coupling agent, an organic peroxide and an additive are collectively melt-kneaded. For example, in Patent Document 1, an inorganic filler surface-treated with a silane coupling agent, a silane coupling agent, an organic peroxide, and a crosslinking catalyst are added to a resin component formed by mixing a polyolefin resin and a maleic anhydride resin. There has been proposed a method in which after sufficiently kneading in a kneader, extrusion molding is carried out with a single screw extruder and then the obtained molded body is immersed in warm water.

JP 2001-101928 A

However, in the above-described conventional silane crosslinking method, the silane coupling agent tends to volatilize during melt-kneading with a Banbury mixer or a kneader. In particular, when the blending amount of the silane coupling agent is set large, and further, when the blending amount of the inorganic filler is set small, the volatilized amount of the silane coupling agent increases.
If the silane coupling agent is volatilized during the melt-kneading, not only black spots are generated in the melt-kneaded product, and therefore, the resulting cross-linked molded product is not only burnt, but also the desired heat resistance can not be imparted. In the present invention, "burn" refers to a cross-linked compact or a combustion product or carbide of the material produced on the surface or inside of the cross-linked compact, and usually a black spot-like area (black point) and Become.

  An object of the present invention is to provide a method for producing a heat-resistant silane-crosslinked resin molded article capable of producing a heat-resistant silane-crosslinked resin molded article excellent in appearance without black spots due to burnout while suppressing volatilization of a silane coupling agent. I assume. Moreover, this invention makes it a subject to provide the heat resistant silane cross-linked resin molded object excellent in the appearance without the black point by burning, and the heat resistant product using the same.

  In the silane crosslinking method, the present inventors rapidly react with the organic peroxide to generate heat due to a large amount of silane coupling agent volatilized by friction etc. during melt-kneading, and the melt-kneaded product exceeds the flash point. It has been found that excessive reaction (combustion reaction) is a factor of black spot formation of the melt-kneaded product. As a result of further investigations, in the silane crosslinking method, the melt-kneaded product obtained by melt-kneading the resin and the inorganic filler in advance, the silane coupling agent and the organic peroxide were once mixed (with the grafting reaction suppressed). It has been found that when the melt-kneading (grafting reaction) is performed later, volatilization of the silane coupling agent can be suppressed to prevent formation of black spots, and a heat-resistant silane-crosslinked resin molded article excellent in appearance without black spots due to burning can be produced. Based on this finding, the present inventors have further studied and made the present invention.

That is, the object of the present invention is achieved by the following means.
The manufacturing method of the heat resistant silane crosslinked resin molded object which has <1> following process (a)-(e).
Process (a): Process of melt-kneading a resin composition containing a polyolefin resin and 1 to 400 parts by mass of an inorganic filler with respect to 100 parts by mass of the resin composition: Process (b): Obtained in process (a) 0.01 to 0.6 parts by mass of an organic peroxide and a graftable reaction site of a polyolefin resin with respect to 100 parts by mass of the melted and kneaded product and 100 parts by mass of the resin composition in the molten and kneaded product Process step (c) of mixing 0.5 to 15 parts by mass of a silane coupling agent having a portion capable of undergoing a chemical reaction at a temperature below the decomposition temperature of the organic peroxide: the mixture obtained in the step (b) By melt-kneading at a temperature above the decomposition temperature of the organic peroxide in the absence of a silanol condensation catalyst to cause the silane coupling agent to graft on the polyolefin resin by radicals generated from the organic peroxide. Step (d) of preparing a silane masterbatch containing a silane graft resin: step of melt-kneading the silane masterbatch and the silanol condensation catalyst and thereafter forming step (e): forming obtained in step (d) A step of bringing a body into contact with water <2> The heat-resistant silane-crosslinked resin molded article according to <1>, wherein the compounding amount of the inorganic filler is 1 to 80 parts by mass with respect to 100 parts by mass of the resin composition. Manufacturing method.
<3> The polyolefin resin is ethylene-vinyl acetate copolymer, ethylene- (meth) acrylic acid copolymer, ethylene- (meth) acrylic acid alkyl copolymer, low density polyethylene, linear low density polyethylene The manufacturing method of the heat resistant silane crosslinked resin molded object as described in <1> or <2> containing at least 1 sort (s) of resin selected from the group which consists of ultra-low density polyethylene, ethylene rubber, and a styrene-type elastomer.
The manufacturing method of the heat resistant silane crosslinked resin molded object of any one of <1>-<3> in which the <4> above-mentioned polyolefin resin contains ethylene rubber.
<5> The method for producing a heat-resistant silane-crosslinked resin molded product according to <4>, wherein the ethylene rubber is ethylene-propylene-diene rubber or ethylene-propylene rubber.
The manufacturing method of the heat resistant silane crosslinked resin molded object as described in any one of <1>-<5> whose <6> silane coupling agent is vinyl trimethoxysilane or vinyl triethoxysilane.
<7> The inorganic filler is at least one selected from the group consisting of silica, aluminum hydroxide, magnesium hydroxide, calcium carbonate, antimony trioxide, clay, magnesium carbonate, zinc borate, zinc hydroxystannate and talc The manufacturing method of the heat resistant silane crosslinked resin molded object as described in any one of <1>-<6>.
The manufacturing method of the heat resistant silane crosslinked resin molded object as described in any one of <1>-<8> which melt-mixes the <8> above-mentioned process (c) using an extrusion apparatus.
The heat resistant product containing the heat resistant silane crosslinked resin molded object manufactured with the manufacturing method of the heat resistant silane crosslinked resin molded object of any one of <9> said <1>-<8>.
The heat resistant product as described in <9> which is an electric wire or an optical fiber cable provided with the coating layer which consists of <10> said heat resistant silane crosslinked resin molded object.
<11> A heat-resistant silane-crosslinked resin molded article produced by the method of producing a heat-resistant resin molded article according to any one of <1> to <8>, wherein the polyolefin resin passes silanol bonds. A heat-resistant silane-crosslinked resin molded article containing a silane-crosslinked resin formed by crosslinking.

  The numerical range represented using "-" in this specification means the range which includes the numerical value described before and after "-" as a lower limit and an upper limit.

The present invention mixes a melt-kneaded product obtained by melt-kneading a resin composition and an inorganic filler in advance, a specific amount of an organic peroxide and a silane coupling agent, and then melt-kneaded to obtain a polyolefin system. Before and / or during melt-kneading of a resin composition containing a resin and a silane coupling agent, the volatilization of the silane coupling agent is suppressed to efficiently form a heat-resistant silane cross-linked resin molded article and heat resistance containing this molded article Sex products can be manufactured. Furthermore, a highly heat-resistant silane-crosslinked resin molded product to which a large amount of inorganic filler is added can be manufactured without using a special machine such as an electron beam crosslinking machine.
Therefore, the present invention can provide a method for producing a heat-resistant silane-crosslinked resin molded article capable of producing a heat-resistant silane-crosslinked resin molded article excellent in appearance without black spots due to burnout by suppressing volatilization of the silane coupling agent. Moreover, the present invention can provide a heat-resistant silane-crosslinked resin molded article excellent in appearance without black spots due to burning and a heat-resistant product using the same.

First, each component used in the present invention will be described.
<Resin composition>
The resin composition used in the present invention contains a polyolefin resin, and may further contain an organic oil, a plasticizer and the like, if necessary.

-Polyolefin resin-
The polyolefin resin is a resin composed of a homopolymer or copolymer of a compound having an ethylenically unsaturated bond, and grafting of a silane coupling agent in the presence of radicals generated from an organic peroxide described later A resin of a polymer having a reactive site (referred to as a grafting reaction site) and a graftable site in the main chain or at the end of the main chain is used. Examples of the site capable of grafting reaction include an unsaturated bond site of a carbon chain, and a carbon atom having a hydrogen atom.
As such a polyolefin resin, those used in conventional heat resistant resin compositions can be used without particular limitation. For example, each resin such as polyethylene, polypropylene, ethylene-α-olefin copolymer, polyolefin copolymer having an acid copolymer component (including an acid ester copolymer component), a rubber or elastomer of these polymers, etc. Can be mentioned. Examples of the rubber or elastomer include ethylene rubber, styrene-based elastomer, copolymerized rubber of alkyl acrylate and ethylene (ethylene acrylic rubber), and the like.
Among them, a polyolefin copolymer having an acid copolymerization component is highly acceptable because it is highly receptive (miscible) to various inorganic fillers including metal hydrates, and can maintain mechanical strength even if a large amount of inorganic filler is blended. Polymer resin (ethylene-vinyl acetate copolymer, ethylene- (meth) acrylic acid copolymer, ethylene- (meth) acrylic acid alkyl copolymer), polyethylene (low density polyethylene, linear low density polyethylene, super It is preferable to include at least one resin selected from the group consisting of low density polyethylene), ethylene rubber and styrenic elastomer. The polyolefin resin more preferably contains ethylene rubber.
The polyolefin resin and each resin described later may be used singly or in combination of two or more.

(Polyethylene resin)
The polyethylene resin may be any polymer resin containing an ethylene component, and excludes homopolymers of ethylene and copolymers of ethylene and an α-olefin (preferably 5 mol% or less) (polypropylene). And resins composed of a copolymer of ethylene and a non-olefin (preferably 1 mol% or less) having only carbon, oxygen and hydrogen atoms as functional groups. In addition, the above-mentioned (alpha)-olefylene and a non-olefin can be used especially without being restrict | limited especially as a well-known thing conventionally used as a copolymerization component of polyethylene.
Examples of the polyethylene resin include high density polyethylene (HDPE), low density polyethylene (LDPE), ultrahigh molecular weight polyethylene (UHMW-PE), linear low density polyethylene (LLDPE), and ultra low density polyethylene (VLDPE). Among them, low density polyethylene, linear low density polyethylene or ultra low density polyethylene is preferable, and low density polyethylene or linear low density polyethylene is more preferable.

(Polypropylene resin)
The polypropylene resin may be a resin of a polymer containing a propylene component as a main component, and a resin such as a homopolymer of propylene (homopolypropylene resin), an ethylene-propylene random copolymer, an ethylene-propylene block copolymer, etc. Can be used.

(Ethylene-α-olefin copolymer resin)
The ethylene-α-olefin copolymer resin preferably includes a resin of a copolymer of ethylene and an α-olefin having 3 to 12 carbon atoms (excluding those corresponding to the above-mentioned polyethylene and polypropylene). .

(Polyolefin copolymer resin having an acid copolymerization component)
The acid copolymerization component (including the acid ester copolymerization component) in the polyolefin copolymer resin having an acid copolymerization component is not particularly limited, but a carboxylic acid compound such as (meth) acrylic acid, vinyl acetate, or Acid ester compounds such as alkyl (meth) acrylates (preferably having a carbon number of 1 to 12) can be mentioned. Examples of polyolefin copolymer resins having an acid copolymerization component include ethylene-vinyl acetate copolymer (EVA), ethylene- (meth) acrylic acid copolymer, ethylene- (meth) acrylic acid alkyl copolymer, etc. Each resin of is mentioned. Among them, each resin of ethylene-vinyl acetate copolymer, ethylene-methyl acrylate copolymer, ethylene-ethyl acrylate copolymer, ethylene-butyl acrylate copolymer is preferable, and receptivity to inorganic filler and heat resistance From the viewpoint of properties, resins of ethylene-vinyl acetate copolymer are more preferable.

(Ethylene rubber)
The ethylene rubber is not particularly limited as long as it is a rubber of a copolymer of ethylene and an α-olefin. For example, as ethylene rubber, preferably, a binary copolymer rubber of ethylene and α-olefin (preferably having 1 to 12 carbon atoms), ethylene and α-olefin (preferably having 1 to 12 carbon atoms) and α- The rubber which consists of a ternary copolymer with the 3rd component which has unsaturated bonds other than an olefin is mentioned. The third component includes conjugated or non-conjugated dienes, and specifically, butadiene, isoprene, 1,3-pentadiene, 2,3-dimethyl-1,3-butadiene, dicyclopentadiene (DCPD), Ethylidene norbornene (ENB), 1,4-hexadiene, etc. may be mentioned. Examples of the binary copolymer rubber include ethylene-propylene rubber (EPM), and examples of the ternary copolymer rubber include ethylene-propylene-diene rubber (EPDM).

(Styrenic elastomer)
As a styrene-type elastomer, what has an aromatic vinyl compound as a structural component in a molecule | numerator is said. As such a styrene-type elastomer, the block copolymer and random copolymer of a conjugated diene compound and an aromatic vinyl compound, or those hydrogenated substances etc. are mentioned. As such a styrene-based elastomer, for example, styrene-ethylene-butylene-styrene block copolymer (SEBS), styrene-isoprene-styrene block copolymer (SIS), hydrogenated SIS, styrene-butadiene-styrene block co-polymer Polymer (SBS), hydrogenated SBS, styrene-ethylene-ethylene-propylene-styrene block copolymer (SEEPS), styrene-ethylene-propylene-styrene block copolymer (SEPS), styrene-butadiene rubber (SBR), Hydrogenated styrene butadiene rubber (HSBR) etc. are mentioned.

  The polyolefin resin (each of the above resins or rubbers) may be acid-modified. It does not specifically limit as an acid used for acid modification, The unsaturated carboxylic acid etc. which are normally used are mentioned.

(Organic oil)
The organic oil includes aromatic oils, paraffinic oils or naphthenic oils, or mixed oils containing these three. As an organic oil, what is normally used for a resin composition can be used without being restrict | limited in particular, A paraffin type oil or a naphthene type oil is preferable. The organic oil is preferably used in combination with the styrenic elastomer. One type of organic oil may be used alone, or two or more types may be used in combination.

-Content of resin composition-
The content of the polyolefin resin in the resin composition is not particularly limited, but is preferably 15 to 100% by mass in terms of the total content with the organic oil. The content of organic oil in the resin composition (the total content with the plasticizer when the resin composition contains a plasticizer) is not particularly limited, but it is preferably 0 to 40% by mass, and 0 to 35%. More preferably, it is%.

In the present invention, the content of each of the above resins included in the polyolefin resin in the resin composition is appropriately set in a range that satisfies the above content of the polyolefin resin, for example, to the following content It is set.
0-98 mass% is preferable, and, as for the content rate of a polyethylene resin, 5-90 mass% is more preferable. 0-40 mass% is preferable, as for the content rate of a polypropylene resin, 2-30 mass% is more preferable, and 2-25 mass% is still more preferable. As for the content rate of ethylene-alpha-olefin copolymer resin, 0-98 mass% is preferable. 0-90 mass% is preferable, and, as for the content rate of polyolefin copolymer resin which has an acid copolymerization component, 0-70 mass% is more preferable. 0-98 mass% is preferable, and, as for the content rate of ethylene rubber, 0-90 mass% is more preferable. 0-40 mass% is preferable, and, as for the content rate of a styrene-type elastomer, 0-30 mass% is more preferable.

<Inorganic filler>
The inorganic filler used in the present invention is not particularly limited as long as it is generally used in conventional heat resistant resin compositions, and the surface thereof may be a hydrogen bond or a covalent bond with a hydrolyzable silyl group of a silane coupling agent described later. It is preferable to have a site that can be chemically bonded by an equal or intermolecular bond. Examples of the site that can be chemically bonded to the hydrolyzable silyl group include an OH group (hydroxy group, water molecule of water or water of crystallization, OH group such as carboxy group), an amino group, an SH group and the like.
As the inorganic filler, for example, aluminum hydroxide, magnesium hydroxide, calcium carbonate, magnesium carbonate, calcium silicate, magnesium silicate, calcium oxide, magnesium oxide, magnesium oxide, aluminum oxide, aluminum nitride, aluminum borate, aluminum borate, hydrated aluminum silicate And metal hydrates such as hydrated magnesium silicate, basic magnesium carbonate, hydrotalcite, and compounds having a hydroxyl group or crystallization water such as talc. Also, boron nitride, silica (crystalline silica, amorphous silica, etc.), carbon, clay, zinc oxide, tin oxide, titanium oxide, titanium oxide, molybdenum oxide, antimony trioxide, silicone compound, quartz, zinc borate, white carbon, Zinc borate, zinc hydroxystannate, zinc stannate and the like can also be mentioned.
Among them, at least one selected from the group consisting of metal hydrates, silica, antimony trioxide, zinc borate and zinc hydroxystannate is preferred, and silica, aluminum hydroxide, magnesium hydroxide, calcium carbonate, antimony trioxide, clay At least one selected from the group consisting of magnesium carbonate, zinc borate, zinc hydroxystannate and talc is more preferable, and aluminum hydroxide or magnesium hydroxide is more preferable.

An inorganic filler can also be used for what was surface-treated by various surface treatment agents. For example, as magnesium hydroxide surface-treated by the silane coupling agent, Kisuma 5L, Kisuma 5P (all are a brand name, Kyowa Chemical Industry Co., Ltd. make), etc. are mentioned.
One type of inorganic filler may be used alone, or two or more types may be used in combination.

When an inorganic filler is used as a powder, the average particle diameter is preferably 0.2 to 10 μm, more preferably 0.3 to 8 μm, and still more preferably 0.4 to 5 μm, Particularly preferred is 0.4 to 3 μm.
When the average particle diameter of the inorganic filler is in the above range, secondary aggregation can be prevented to obtain a molded product having a bumpless appearance.
The average particle diameter of the inorganic filler is determined by dispersing the inorganic filler in alcohol or water and using an optical particle size measuring device such as a laser diffraction / scattering particle diameter distribution measuring device.

<Organic peroxide>
The organic peroxide used in the present invention generates radicals at least by thermal decomposition, and as a catalyst, a grafting reaction by a radical reaction of a silane coupling agent to a polyolefin-based resin (a grafting reaction site of a silane coupling agent and It is a covalent bond forming reaction with a graftable reaction site of the polyolefin resin, and also functions to cause (radical) addition reaction. For example, when the silane coupling agent contains an ethylenically unsaturated group as a grafting reaction site, the grafting reaction by the radical reaction (including the abstraction of hydrogen radicals from the polyolefin resin) of the ethylenically unsaturated group and the polyolefin resin is It works to make it happen.
The organic peroxide is not particularly limited as long as it has the above function. For example, a compound represented by the general formula: R ¹ -OO-R ² , R ³ -OO-C (= O) R ⁴ or R ⁵ C (= O) -OO (C = O) R ⁶ is preferable. Here, R ^{1 to} R ⁶ each independently represent an alkyl group, an aryl group or an acyl group. Among R ^{1 to} R ⁶ of each compound, preferred are those in which all are alkyl groups, or those in which either is an alkyl group and the remainder is an acyl group. As such an organic peroxide, those used in radical polymerization or conventional silane crosslinking methods can be used without particular limitation, and benzoyl peroxide, dicumyl peroxide, 2,5-dimethyl-2, 5-di- (tert-butylperoxy) hexane or 2,5-dimethyl-2,5-di- (tert-butylperoxy) hexyne-3 is preferred.

80-195 degreeC is preferable and, as for the decomposition temperature of an organic peroxide, 125-180 degreeC is especially preferable. In the present invention, the decomposition temperature of the organic peroxide means a temperature at which a decomposition reaction occurs in two or more kinds of compounds in a certain temperature or temperature range when heating the organic peroxide of a single composition. means. Specifically, it refers to a temperature at which heat absorption or heat generation starts when heated from room temperature at a temperature rising rate of 5 ° C./minute in a nitrogen gas atmosphere by thermal analysis such as DSC method.
The organic peroxide may be used alone or in combination of two or more.

<Silane coupling agent>
The silane coupling agent used in the present invention includes a site (group or atom) capable of causing a grafting reaction to a site capable of grafting reaction of a polyolefin resin in the presence of radicals generated by decomposition of organic peroxide, and silanol It is not particularly limited as long as it has a condensable hydrolyzable silyl group. As such a silane coupling agent, the silane coupling agent used for the conventional silane crosslinking method is mentioned. Among them, for example, a compound represented by the following general formula (1) can be used.

In the general formula (1), R _a11 represents a group containing an ethylenically unsaturated group, and R _b11 represents an aliphatic hydrocarbon group, a hydrogen atom or Y ¹³ . Y ¹¹ , Y ¹² and Y ¹³ represent hydrolyzable organic groups. Y ¹¹ , Y ¹² and Y ¹³ may be the same or different.
The R _a11 group corresponds to a grafting reaction site, and examples of the group that can be taken as R _a11 include a vinyl group, a (meth) acryloyloxyalkylene group, and a p-styryl group, with a vinyl group being preferable.
As an aliphatic hydrocarbon group which can be taken as R _b11 , an aliphatic hydrocarbon group having 1 to 8 carbon atoms excluding an aliphatic unsaturated hydrocarbon group can be mentioned. R _b11 is preferably Y ¹³ described later.
Y ¹¹ , Y ¹² and Y ¹³ represent silanol-condensable reactive sites (hydrolyzable organic groups). For example, a C1-C6 alkoxy group, a C6-C10 aryloxy group, a C1-C4 acyloxy group is mentioned, An alkoxy group is preferable. Specific examples of the hydrolyzable organic group include methoxy, ethoxy, butoxy, acyloxy and the like. Among these, methoxy or ethoxy is preferable from the viewpoint of the reactivity of the silane coupling agent.

As such a silane coupling agent, preferably a silane coupling agent having an unsaturated group having a high hydrolysis rate, more preferably R _b11 is Y ¹³ and Y ¹¹ , Y ¹² and Y ¹³ are the same. Is a silane coupling agent. Specifically, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltributoxysilane, vinyldimethoxyethoxysilane, vinyldimethoxybutoxysilane, vinyldiethoxybutoxysilane, allyltrimethoxysilane, allyltriethoxysilane, vinyltriacetoxysilane And (meth) acryloxysilanes such as methacryloxypropyltrimethoxysilane, methacryloxypropyltriethoxysilane, methacryloxypropylmethyldimethoxysilane and the like. Among them, vinyltrimethoxysilane or vinyltriethoxysilane is particularly preferable.
The silane coupling agent may be used alone or in combination of two or more.
The silane coupling agent may be used as it is or may be diluted with a solvent.

<Silanol condensation catalyst>
The silanol condensation catalyst used in the present invention causes the silane coupling agent grafted to the polyolefin resin to undergo a silanol condensation reaction (promotion) in the presence of water. Based on the function of the silanol condensation catalyst, the polyolefin resin is crosslinked via the silane coupling agent. As a result, it is possible to obtain a silane-crosslinked resin molded article excellent in heat resistance.
Such a silanol condensation catalyst is not particularly limited, and examples thereof include organic tin compounds, metal soaps, and platinum compounds. Specifically, organotin compounds such as dibutyltin dilaurate, dioctyltin dilaurate, dibutyltin diacrylate, dibutyltin diacetate, etc., zinc stearate, lead stearate, barium stearate, calcium stearate, sodium stearate, sodium stearate, lead naphthenate, sulfuric acid Examples include lead, zinc sulfate and organic platinum compounds. Preferably it is an organotin compound.
The silanol condensation catalyst may be used alone or in combination of two or more.

<Carrier resin>
In the present invention, the silanol condensation catalyst may be used as it is, but can be used as a mixture with a resin. The resin to be melt-kneaded (carried) as the silanol condensation catalyst (referred to as carrier resin) is not particularly limited, but the polyolefin-based resin described in the above resin composition can be used. Preferably, it is a polyethylene resin in that it has high affinity to the silanol condensation catalyst and can impart high heat resistance. One type of carrier resin may be used, or two or more types may be used.

<Additives>
In the present invention, various additives can be used. Examples of the additives include various additives generally used in electric wires, electric cables, electric cords, members for automobiles, office automation equipment, building members, sundries, sheets, foams, tubes, pipes and the like. Examples of such additives include antioxidants, crosslinking aids, lubricants, metal deactivators, flame retardants (supporting agents), and resins other than the above-mentioned polyolefin resins.
As the antioxidant, those generally used in conventional heat-resistant resin compositions can be used without particular limitation, and examples thereof include benzimidazole-based antioxidants, amine-based antioxidants, and phenolic-based antioxidants. And sulfur based antioxidants, hydrazine based antioxidants and the like.

<Method of producing heat resistant silane cross-linked resin molded product>
Next, the method for producing the heat-resistant silane-crosslinked resin molded product of the present invention (hereinafter sometimes referred to as the production method of the present invention) will be specifically described.
The production method of the present invention comprises the following steps (a) to (e).
Step (a): Step of melting and kneading a resin composition containing a polyolefin resin and 1 to 400 parts by mass of an inorganic filler with respect to 100 parts by mass of the resin composition: Step (b): obtained in step (a) And 0.01 to 0.6 parts by mass of organic peroxide and 100 parts by mass of the resin composition in the molten and kneaded product, and a grafting reaction between the polyolefin resin and the grafting reaction site. Step (c) of mixing 0.5 to 15 parts by mass of a silane coupling agent having a reactive site at a temperature below the decomposition temperature of the organic peroxide: the mixture obtained in step (b) Melt-kneading at a temperature above the decomposition temperature of the organic peroxide in the absence of a silanol condensation catalyst, and causing the silane coupling agent to graft on the polyolefin resin by radicals generated from the organic peroxide. Step (d) of preparing a silane masterbatch containing a silane graft resin: step of melt-kneading the silane masterbatch and the silanol condensation catalyst and thereafter forming step (e): the molded product obtained in step (d) Contacting with water (e)

In the production method of the present invention, the resin composition, the inorganic filler, the organic peroxide, the silane coupling agent and the silanol condensation catalyst, and further the additive are melt-kneaded (in the presence of all the components) (melt-mixing) Step (a), step (b), step (c) and step (d) are performed in this order, and the respective components are melt-kneaded in a specific order. That is, first, the resin composition and the inorganic filler are melt-kneaded, and then the obtained molten mixture, the organic peroxide and the silane coupling agent are premixed (premixed) while suppressing the grafting reaction, and then These are melt-kneaded to cause a grafting reaction, and finally the silanol condensation catalyst is melt-kneaded. By melt-kneading the components in this order, volatilization of the silane coupling agent can be suppressed during melt-kneading in the presence of the silane coupling agent (step (c) and step (d)). Therefore, it is possible to suppress reaction with the organic peroxide in the state where the silane coupling agent is volatilized, there is no generation of reaction heat, and the temperature in the system is volatile component (silane coupling agent) and melt-kneaded product (resin The composition is maintained below the flash point of the melt-kneaded product of the inorganic filler and the melt-kneaded product of the silane coupling agent and the organic peroxide. As a result, it is possible to prevent the formation of black spots of the melt-kneaded product, and further, the burning (the generation of black spots) of the heat-resistant silane-crosslinked resin molded article.
The details of the reason are not clear yet, but are considered as follows.
During the melt-kneading of the silane coupling agent, the resin composition and the like, the silane coupling agent volatilizes rapidly and in some cases, in large amounts, in some cases due to friction and the like. The volatilized silane coupling agent rapidly reacts with the organic peroxide present in the vicinity of the surface of the melt-kneaded product to cause a radical polymerization reaction between the silane coupling agents. This radical polymerization reaction is an exothermic reaction and is dissipated as the polymerization reaction proceeds. When the calorific value due to the heat radiation increases, the temperature in the system exceeds the flash point of the volatile component and the melt-kneaded product, and the melt-kneaded product tends to cause black spots.
However, in the production method of the present invention, since the respective components are sequentially melt-kneaded in a specific mixing order, the friction generated during the melt-kneading can be reduced, and the rapid and large volatilization of the silane coupling agent can be suppressed. Furthermore, since the molten mixture of the resin composition and the inorganic filler, the silane coupling agent, and the crosslinking agent are uniformly dispersed in advance, the reaction (addition reaction, condensation reaction) between the silane coupling agents does not easily occur. The silane coupling agent grafts on the polyolefin resin stably. As a result, it is possible to prevent the formation of black spots of the melt-kneaded product, and further, the burning of the heat-resistant silane-crosslinked resin molded product.

(Step (a))
In the production method of the present invention, before the resin composition, the silane coupling agent and the organic peroxide are melt-kneaded (the grafting reaction of the silane coupling agent to the resin), the resin composition and the inorganic filler are mixed together. Melt and knead (step (a)).
In the step (a), the resin composition includes “a mode in which the total amount (100 parts by mass) is blended” and “a mode in which a portion is blended”. In the step (a), when a part of the resin composition is blended, the remainder of the resin composition may be blended in any step other than the step (a), but the step ( It is preferable to mix | blend as carrier resin which carry | supports a silanol condensation catalyst in d). When a part of the resin composition is blended in the step (a), 100 parts by mass of the total blending amount of the resin composition blended in the step (a) and the other steps is used as a basis of the blending amount of each component (B) etc.) When the balance of the resin composition is blended in another process, particularly in step (d), the resin composition is preferably blended in an amount of 55 to 99% by mass, more preferably 60 to 95% by mass in step (a). In other processes, preferably 1 to 45% by mass, more preferably 5 to 40% by mass is blended.

In process (a), the compounding quantity of an inorganic filler is 1-400 mass parts with respect to 100 mass parts of resin compositions, Preferably it is 30-280 mass parts. By setting the compounding amount to 1 to 400 parts by mass, the grafting reaction of the silane coupling agent in the step (c) becomes uniform, the heat resistance of the heat-resistant silane cross-linked resin molded product is high, and the appearance rough is prevented. it can. In the present invention, appearance defects due to agglomerates (blocks) such as cross-linked products of resins, condensates of silane coupling agents, aggregates of inorganic fillers, etc. are referred to as "rough appearance" and the above-mentioned "no black spots due to burning" We distinguish it from "excellent appearance" and use it. Furthermore, it is easy to knead | mix a silane coupling agent and an organic peroxide uniformly with respect to the melt-kneaded thing of a resin composition and an inorganic filler, and it can be excellent in productivity.
In the production method of the present invention, as described above, since the volatilization of the silane coupling agent can be prevented, the compounding amount of the inorganic filler is added regardless of the preferable compounding amount for the purpose of productivity (reduction of extrusion load) and the like. It can also be set low. For example, it can be set to 1 to 80 parts by mass, can be set to 1 to 60 parts by mass, and can be set to 1 to 30 parts by mass with respect to 100 parts by mass of the resin composition. .

The melt-kneading in the step (a) may be any method by which the resin composition and the inorganic filler can be melt-kneaded, and is usually carried out under the melting of the resin composition or the polyolefin resin in the resin composition (melt knead) Can be mentioned. That is, the melt-kneading temperature is a temperature equal to or higher than the melting point of the resin composition or the polyolefin resin, and is preferably equal to or lower than the flash point of the resin composition or the polyolefin resin, or lower than the decomposition temperature of the inorganic filler. For example, it can be set preferably at 80 to 250 ° C., more preferably 100 to 240 ° C., depending on the melting point and the flash point of the resin composition or the polyolefin resin. Other conditions, for example, the kneading time can be set appropriately.
The kneading method is not particularly limited as long as it is a method commonly used for rubber, plastic and the like. The kneader is appropriately selected according to, for example, the amount of the inorganic filler. For example, a single screw extruder, a twin screw extruder, a roll, a Banbury mixer, or various kneaders can be mentioned. Among them, closed mixers such as Banbury mixers and various kneaders are preferable in terms of resin dispersibility.
The melt-kneading method of the resin composition is not particularly limited. For example, the resin composition prepared in advance may be melt-kneaded, or the resin, the organic oil, etc. to be contained in the resin composition may be separately melt-kneaded.

  In the step (a), a melt-kneaded product of the resin composition and the inorganic filler is obtained.

(Step (b))
Next, in the production method of the present invention, the melt-kneaded product obtained in step (a) prior to the grafting reaction (step (c)) of the silane coupling agent and the resin, and the resin in the melt-kneaded product 0.01 to 0.6 parts by mass of organic peroxide and 0.5 to 15 parts by mass of silane coupling agent are mixed with 100 parts by mass of the composition at a temperature lower than the decomposition temperature of the organic peroxide Do (step (b)).

  In the step (b), the compounding amount of the organic peroxide is 0.01 to 0.6 parts by mass, preferably 0.05 to 0. 100 parts by mass of the resin composition in the melt-kneaded product. 3 parts by mass. By setting the compounding amount of the organic peroxide to 0.01 to 0.6 parts by mass, it is possible to carry out the grafting reaction in an appropriate range, and without generating agglutination caused by a crosslinked gel or the like A silane masterbatch excellent in extrudability can be obtained.

The compounding quantity of a silane coupling agent is 0.5-15 mass parts with respect to 100 mass parts of resin compositions in melt-kneaded material, Preferably it is 1-8 mass parts. By setting the compounding amount to 0.5 to 15 parts by mass, excessive volatilization of the silane coupling agent can be suppressed in the step (c) and the step (d) described later, there is no burning, and high heat resistance Can be produced. Furthermore, the condensation of the silane coupling agents can be suppressed to produce a heat-resistant silane-crosslinked resin molded product without any rough surface.
In the production method of the present invention, as described above, since the volatilization of the silane coupling agent can be prevented, the compounding amount of the silane coupling agent can also be set high for the purpose of improving the heat resistance (crosslinking density). For example, it can set to 3.0 mass parts or more with respect to 100 mass parts of resin compositions.

The mixing in the step (b) may be any method by which the melt-kneaded product, the organic peroxide, and the silane coupling agent can be mixed, and dry mixing (dry blending) in which heating and non-heating are mixed is preferable. The mixing conditions are usually carried out at a temperature lower than the decomposition temperature of the organic peroxide, and the above components are mixed while suppressing the occurrence of the grafting reaction. The mixing temperature is preferably 10 to 50 ° C., more preferably room temperature (25 ° C.) to 40 ° C., and may be set to several minutes to several hours or so. For the mixing in the step (b), a commonly used mixer, for example, the kneading apparatus described in the step (a) can be used.
The mixing in step (b) is preferably performed in the absence of a silanol condensation catalyst to inhibit the condensation reaction of the silane coupling agent. Melt-kneading in the absence of a silanol condensation catalyst is as described in the following step (c).

  In step (b), a (preliminary) mixture of the melt-kneaded product, the organic peroxide and the silane coupling agent is obtained.

(Step (c))
In the production method of the present invention, the mixture obtained in step (b) is then melt-kneaded in the absence of a silanol condensation catalyst at a temperature above the decomposition temperature of the organic peroxide (step (c)).
In the present invention, to melt and knead in the absence of a silanol condensation catalyst means to melt and knead the silanol condensation catalyst substantially without mixing. That is, it does not exclude the silanol condensation catalyst which is inevitably present, and means that it may be present as long as the problems of the following kneadability and formability by the silanol condensation of the silane coupling agent do not occur. Do. For example, the silanol condensation catalyst may be present as long as it is 0.01 parts by mass or less with respect to 100 parts by mass of the resin composition.
By performing the melt-kneading in the absence of a silanol condensation catalyst, the condensation reaction of the silane coupling agent in this step can be suppressed, and the kneadability is excellent (easy to melt and knead) and the formability is excellent ( It can be extruded into the desired shape).

Melt-kneading in step (c) is carried out at a temperature above the decomposition temperature of the organic peroxide, preferably the decomposition temperature of the organic peroxide + (25 to 110) ° C, for example 150 to 230 ° C. The decomposition temperature is preferably set after the resin composition is melted. Other melt-kneading conditions, for example, the kneading time can be set appropriately.
In step (c), the grafting reaction site of the silane coupling agent and the grafting reaction site of the polyolefin resin are caused to undergo a grafting (bonding) reaction by radicals generated from the organic peroxide. If the kneading is carried out below the decomposition temperature of the organic peroxide, the silane grafting reaction does not occur, and not only the desired heat resistance can not be obtained, but also the organic peroxide is reacted during extrusion, and it is molded into the desired shape It may not be possible.
The melt-kneading in the step (c) can be carried out using the kneading apparatus described in the step (a), and among them, it is preferable to carry out using the extrusion device (single screw extruder, twin screw extruder).

In step (c), a grafting reaction is carried out to synthesize a silane graft resin in which a silane coupling agent is covalently bonded to a polyolefin resin, and a silane master batch containing this silane graft resin is prepared as a reaction composition. can do. In this grafting reaction, usually, one molecule of silane coupling agent is added to one graftable site, but the present invention is not limited thereto.
In the silane graft resin contained in the silane master batch (silane MB) to be obtained, the silane coupling agent graft-reacts on the resin to such an extent that it can be molded in the step (d). The inorganic filler in the silane MB may or may not be bonded to the silane coupling agent (hydrolyzable silyl group).

(Step (d))
Next, in the production method of the present invention, the silane masterbatch obtained in step (c) and the silanol condensation catalyst are melt-kneaded and then shaped (step (d)).

In the melt-kneading in the step (d), it is preferable to melt-knead the silanol condensation catalyst and the carrier resin in advance to prepare a catalyst master batch (catalyst MB) and use it.
As a carrier resin, when melt-kneading a part of resin composition at the said process (a), the remainder of a resin composition is used. In this case, the blending ratio of the remaining portion of the resin composition and the silanol condensation catalyst is not particularly limited, and is set to satisfy the blending amount of the resin composition and the blending amount of the silanol condensation catalyst. Moreover, resin other than the said resin composition can be used as carrier resin. In this case, the compounding amount of the carrier resin is preferably 1 to 60 parts by mass, more preferably 2 to 50 parts by mass, and still more preferably 2 to 40 parts by mass with respect to 100 parts by mass of the resin composition.
Furthermore, the catalyst MB may contain an inorganic filler. The content of the inorganic filler in the catalyst MB is not particularly limited, but is preferably 350 parts by mass or less with respect to 100 parts by mass of the carrier resin. If the amount of filler is too large, the silanol condensation catalyst may be difficult to disperse, and the silanol condensation reaction may be difficult to proceed. On the other hand, when the amount of the carrier resin is too large, the degree of crosslinking of the molded article may be reduced, and desired heat resistance may not be obtained.
The melt-kneading of the carrier resin and the silanol condensation catalyst may be performed by melting the resin composition. This melt-kneading can be performed in the same manner as the melt-kneading in the above step (a). For example, the kneading temperature can be set to 80 to 250 ° C., more preferably 100 to 240 ° C. Other conditions, for example, the kneading time can be set appropriately.

In the step (d), the silane MB and the silanol condensation catalyst (silanol condensation catalyst itself or catalyst MB) are melt-kneaded.
The blending amount of the silanol condensation catalyst is preferably 0.01 to 0.6 parts by mass, more preferably 0.001 to 0.4 parts by mass with respect to 100 parts by mass of the resin composition. When the blending amount of the silanol condensation catalyst is within the above range, the crosslinking reaction by the silanol condensation reaction of the silane coupling agent tends to proceed almost uniformly, and the heat resistance of the heat-resistant silane cross-linked resin molded product is enhanced, the appearance becomes rough and physical properties Can be prevented, and the productivity is also improved.
The melt-kneading in the step (d) may be performed by melting the resin composition, and can be performed, for example, in the same manner as the melt-kneading in the step (a). The step (d) is carried out while suppressing the silanol condensation reaction of the coupling agent grafted onto the polyolefin resin. For example, in the step (d), it is preferable to carry out under the condition that the amount of water is small, and it is preferable not to be kept in a high temperature state for a long time in a state where the silane MB and the silanol condensation catalyst are kneaded.
Before melt-kneading in the step (d), the respective components can be mixed, for example, dry-blended under non-melting of the polyolefin resin or carrier resin. The method and conditions of dry blending are not particularly limited, and examples thereof include dry mixing in step (b) and the conditions thereof.
Thus, a heat-resistant silane crosslinkable resin composition which is a melt-kneaded product of silane MB and a silanol condensation catalyst is obtained.

In the step (d), the heat resistant silane crosslinkable resin composition is molded.
Molding of the heat-resistant silane crosslinkable resin composition is sufficient as long as the heat-resistant silane crosslinkable resin composition can be molded, and an appropriate molding method and molding conditions are selected according to the form of the resin cross-linked molded product. The molding method includes extrusion molding using an extruder, extrusion molding using an injection molding machine, and molding using another molding machine.
Extrusion is preferably applied when the heat resistant product of the present invention is a wiring material, in particular a wire or an optical fiber cable. Extrusion can be performed using a general-purpose extruder. The extrusion temperature depends on the type of resin composition and carrier resin, and the conditions of extrusion speed (take-up speed), but the cylinder part is 120 to 180 ° C and the crosshead part (die temperature) is about 160 to 190 ° C. It is preferable to set to a degree.

In the step (d), the melt-kneading and the shaping can be carried out simultaneously or continuously. That is, as an embodiment of melt-kneading, for example, a mode in which a molding material (silane MB and silanol condensation catalyst (catalyst MB)) is melt-kneaded in or immediately before extrusion molding can be mentioned. For example, a mixture obtained by mixing (dry blending) silane MB and a silanol condensation catalyst at normal temperature or high temperature (in a non-molten state) may be introduced into a molding machine and melt-kneaded. Alternatively, the silane MB and the silanol condensation catalyst may be melt-kneaded into pellets, and then introduced into a molding machine to be melt-kneaded again. More specifically, it is possible to employ a series of processes in which a mixture of silane MB and silanol condensation catalyst is melt-kneaded in a coating apparatus and then extrusion coated on the outer peripheral surface of a conductor or the like to form a desired shape.
As described above, a molded article of the heat resistant silane crosslinkable resin composition is obtained.

The molding of the heat-resistant silane crosslinkable resin composition (silane graft resin contained in this molding) is a non-crosslinked product in which the hydrolyzable silyl group derived from the silane coupling agent is not subjected to silanol condensation. In practice, partial cross-linking (partial cross-linking) can not be avoided by the melt-kneading in the step (d), but it is preferable that at least the moldability of the resulting molded article is maintained.
In the silane graft resin in the molded body, the hydrolyzable silyl group may or may not be bonded or adsorbed to the inorganic filler.

In the production method of the present invention, the additives may be kneaded or mixed in any step, and the mixing order in each step is not particularly limited.
The additive is preferably added to the carrier resin, and in particular, the antioxidant and the metal deactivator are preferably added to the carrier resin so as not to inhibit the grafting reaction of the silane coupling agent to the resin. It is also preferable to add a lubricant to the carrier resin. Furthermore, it is preferable that the cross-linking coagent is not substantially mixed at the time of preparation of the catalyst MB in step (a), step (c) and step (d). When the crosslinking aid is not substantially mixed, the crosslinking reaction between the resin components through the crosslinking aid is unlikely to occur during the melt-kneading, and the appearance roughening due to gelation can be prevented. Moreover, the grafting reaction to the resin of a silane coupling agent tends to occur, and it becomes what was excellent in heat resistance. Here, the fact that the coagent is not substantially mixed does not exclude the coagent which is inevitably present, but means that it may be present to such an extent that the above-mentioned advantages are not impaired.
In the production method of the present invention, the blending amount of the additive is not particularly limited, and can be appropriately set in a range that does not impair the intended effect. Although the compounding quantity of antioxidant can be set suitably, Preferably it is 0.1-15.0 mass parts with respect to 100 mass parts of resin compositions, More preferably, it is 0.1-10 mass parts.

(Step (e))
Next, in the production method of the present invention, the molded article of the heat-resistant silane crosslinkable resin composition obtained in the step (d) is brought into contact with water to cause crosslinking (step (e)). In the step (d), the hydrolyzable silyl group of the silane coupling agent is hydrolyzed by water to form silanol (OH group bonded to a silicon atom), and the silanol condensation catalyst present in the molded body Is condensed (dehydration) to cause a crosslinking reaction.
Step (e) can be carried out by a conventional method. The above condensation reaction proceeds only by storage at normal temperature. Therefore, the molded body of the heat resistant silane crosslinkable resin composition and the water do not have to be positively brought into contact with each other. In order to accelerate this condensation reaction, the molded article of the heat-resistant silane crosslinkable resin composition can be positively brought into contact with water. As a method of positively contacting with water, for example, water immersion in water (warm water), charging to a moist heat tank, exposure to high temperature water vapor and the like can be mentioned. In addition, pressure may be applied to allow water to permeate inside.

  Thus, the production method of the present invention is carried out to produce a heat resistant silane cross-linked resin molded product.

<Heat resistant silane cross-linked resin molded product>
The heat-resistant silane-crosslinked resin molded article of the present invention is produced by the production method of the present invention, and contains a silane-crosslinked resin in which a polyolefin resin is crosslinked via silanol bonds. This silane cross-linked resin has a cross-linked portion in which hydrolyzable silyl groups derived from the silane coupling agent in the above-mentioned silane graft resin are silanol-bonded, and part of the hydrolysable silyl group is bonded to the inorganic filler or It may be adsorbed.
This heat-resistant silane-crosslinked resin molded product is manufactured by suppressing the volatilization of the silane coupling agent, has an excellent appearance without black spots due to burning, and exhibits high heat resistance.

As described above, the production method of the present invention suppresses the volatilization of the silane coupling agent, and minimizes the burning and appearance roughening of the finally obtained molded product, and has a heat resistant silane crosslinked resin having a good appearance. It is possible to produce a molded body. In particular, it is effective when the blending amount of the inorganic filler is reduced or when the blending amount of the silane coupling agent is increased. The production method of the present invention significantly reduces burning and dispersion defects of the molded product, as compared with the method in which the resin composition, the inorganic filler, the organic peroxide, the silane coupling agent and the silanol condensation catalyst are collectively melt-blended. It can be improved (suppressed). In addition, compared with a method in which an inorganic filler, a silane coupling agent and an organic peroxide are mixed and then melt-kneaded with a resin composition, burning of the molded body can be improved.
In the method of producing a heat-resistant silane-crosslinked resin molded product, when the silane coupling agent volatilizes in a large amount, black spots may be formed in the melt-kneaded product, which may cause the worst ignition, resulting in safety concerns. However, according to the production method of the present invention, the volatilization of the silane coupling agent can be suppressed, and high safety can be ensured.

<Application of manufacturing method of heat resistant product and silane cross-linked resin molded product>
(Heat resistant product)
The heat-resistant product of the present invention is a product (including semi-finished products, parts, members and the like) containing a silane-crosslinked resin molded product, and may be a product consisting only of the silane-crosslinked resin molded product. As such heat resistant products, for example, other heat resistant flame retardant wire parts, flame retardant heat resistant sheets, flame retardant heat resistant films, other various heat resistant molded articles, specifically power plug, connector, sleeve, box Examples thereof include tape base materials, tubes, sheets, wiring materials used for internal and external wiring of electric and electronic devices, and molded parts such as insulators and sheaths of electric wires.
The heat-resistant product of the present invention is preferably a wiring material, particularly an electric wire or an optical fiber cable, having a silane-crosslinked resin molding as a coating layer.

(Application of manufacturing method of silane cross-linked resin molded product)
The method of the present invention can be applied to the production of a heat-resistant product comprising a silane-crosslinked resin molded product, such as the heat-resistant product of the present invention. The manufacturing method of this invention is suitably applied to manufacture of a wiring material, and can form the coating layer (insulator, sheath) of a wiring material.
When manufacturing a wiring material according to the manufacturing method of the present invention, preferably, while melting and kneading the silane MB and silanol condensation catalyst obtained in step (c) and (molding material) in an extruder (extrusion coating apparatus), The resulting heat resistant silane crosslinkable resin composition is extrusion molded on the outer periphery of a conductor or the like. Thus, a conductor etc. can be coat | covered with heat resistant silane crosslinking resin composition, and a wiring material can be manufactured.
Such a heat-resistant product is a heat-resistant silane-crosslinked resin molded product which is high in heat resistance and does not melt even at high temperature even if a large amount of inorganic filler is added, and general-purpose extrusion coating without using a special machine such as an electron beam crosslinking machine It can be molded using an apparatus. As a conductor to be used, a conductor such as soft copper or a single wire or a stranded wire or a tensile strength fiber may be used, or a bare wire or a tin-plated or enamel-coated one may be used. As a metal material which forms a conductor, soft copper, a copper alloy, aluminum etc. are mentioned. The 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 relating to the compounding amount of each example represent parts by mass unless otherwise specified. Moreover, a blank for each component means that the compounding quantity of a corresponding component is 0 mass part.

The detail of each component (compound) shown in Table 1 and Table 2 is shown below.
<Resin composition>
UE-320: Novatec LL (trade name), LLDPE, Evolue SP1540 manufactured by Mitsubishi Yuka Co., Ltd .: trade name, LLDPE, manufactured by Prime Polymer Co., Ltd.
EC9: Novatec PP (trade name), polypropylene resin, EV 360 manufactured by Japan Polypropylene Corporation: Evaflex EV 360 (trade name), ethylene-vinyl acetate copolymer, Mitsui-Dupont Polychemicals Co., Ltd.)
Septon 4077: trade name, styrenic elastomer (SEEPS), Kuraray Diana Process PW 90: trade name, paraffin oil, Idemitsu Kosan Mitsui EPT0045H: trade name, EPM, Mitsui Chemical Co. Mitsui EP T3092 EPM: trade name, EPDM (Ethylene-propylene-diene rubber), Nodel 3720 manufactured by Mitsui Chemicals, Inc .: trade name, EPDM (ethylene-propylene-ethylidene norbornene rubber), manufactured by Dow Chemical Company <Inorganic filler>
Magnesium hydroxide: Kisuma 5L (trade name), average particle diameter 0.8 μm, aluminum hydroxide manufactured by Kyowa Chemical Industry Co., Ltd .: OL-104 (trade name), average particle diameter 1.2 μm, calcium carbonate manufactured by HYUBER: softon 2200 (Trade name), average particle diameter 1.5 μm, antimony trioxide manufactured by Bihoku Powder Co., Ltd .: PATOX-C (trade name), average particle diameter 3.5 μm, silica manufactured by Nippon Seisei Co., Ltd .: crystallite 5X (trade name) , Average particle diameter 1.2μm, manufactured by Ryumori <organic peroxide>
Perhexa 25B: trade name, 2,5-dimethyl-2,5-di (tert-butylperoxy) hexane, decomposition temperature 179 ° C, manufactured by NOF Corp. <silane coupling agent>
KBM-1003: trade name, vinyltrimethoxysilane, Shin-Etsu Chemical KBE-1003: trade name, vinyltriethoxysilane, Shin-Etsu Chemical Co., Ltd. <silanol condensation catalyst>
Adekastab OT-1: trade name, dioctyl tin dilaurate, manufactured by Adeka <Antioxidant>
Irganox 1010: trade name, pentaerythritol tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], manufactured by BASF

In Examples 1 to 10 and Comparative Examples 1 to 7, a part (95% by mass) of 100% by mass of the resin composition is used in the step (a), and the remaining part (5% by mass) is a carrier in the step (d) Used as a resin.
Examples 1 to 10
The resin, organic oil and inorganic filler shown in the resin composition column of Table 1 are introduced into the 2L Banbury mixer made by Nippon Roll in the compounding amounts shown in Table 1, and after melt-kneading at a kneading temperature of 180 to 190 ° C for about 8 minutes The material was discharged at a material discharge temperature of 180 to 190 ° C. to obtain a melt-kneaded product (step (a)).
Next, the obtained melt-kneaded product, the silane coupling agent and the organic peroxide are introduced into a Toyo Seiki 10 L Henschel mixer at the compounding ratio shown in Table 1 and then kept for 8 minutes at room temperature in the absence of a silanol condensation catalyst. Mixing (dry blending) gave a dry blend as a premix (step (b)).
Next, the obtained dry blend is charged into a 40 mm single screw extruder (with vent holes), and the extruder temperature is set to the decomposition temperature of the organic peroxide without charging the silanol condensation catalyst (in the absence thereof). To 190 ° C., the head temperature was set to 200 ° C., and the mixture was melt-kneaded and extruded. The extruded strand was water-cooled and then cut to obtain pellets of silane MB (step (c)).

On the other hand, each component (carrier resin, silanol condensation catalyst and antioxidant) shown in the component column for catalyst MB shown in Table 1 is melt-kneaded at 180 to 190 ° C. in the amount shown in Table 1 with a Banbury mixer The temperature was set to 180-190 ° C. to obtain catalyst MB. Then, after dry blending the silane MB and the catalyst MB in the proportions shown in Table 1 (the proportion of the resin composition used in step (a) and the carrier resin used for preparation of the catalyst MB to be 100% by mass) It introduce | transduced into the extruder (The ratio of screw effective length L and diameter D: L / D24, compression part screw temperature 190 degreeC, head temperature 200 degreeC) provided with the screw with a diameter of 40 mm. The extrusion coating (heat-resistant silane crosslinkable resin composition) with a thickness of 1 mm on the outside of the 1 / 0.8 TA conductor while melt-kneading silane MB and catalyst MB in this extruder (preparation of heat-resistant silane crosslinkable resin composition) A molded product was formed to obtain a coated conductor having an outer diameter of 2.8 mm (step (d)).
The resulting coated conductor is left in an environment at a temperature of 80 ° C. and a relative humidity of 95% for 24 hours to bring the molded body of the heat-resistant silane crosslinkable resin composition into contact with water, thereby forming the heat-resistant silane cross-linked resin molded body The electric wire (heat-resistant product) which has a coating layer which consists of is manufactured (process (e)).

<Comparative Examples 1 to 7>
Each component (resin, organic oil, inorganic filler, silane coupling agent and organic peroxide) shown in the component column for silane MB in Table 2 is introduced into Nippon Roll 2L Banbury mixer in the amount shown in Table 2. After melt-kneading at a kneading temperature of 160 to 200 ° C. for about 8 minutes, it was discharged at a material discharge temperature of 200 ° C. to obtain a silane master batch.
On the other hand, each component (carrier resin, silanol condensation catalyst and antioxidant) shown in the component column for catalyst MB shown in Table 2 is melt-kneaded at 180 to 190 ° C. in the amount shown in Table 2 with a Banbury mixer The temperature was set to 180-190 ° C. to obtain catalyst MB.
Then, after dry blending the silane MB and the catalyst MB at a ratio shown in Table 2 (ratio of the resin composition used for preparing the silane MB and the carrier resin used for preparing the catalyst MB to be 100% by mass), It introduce | transduced into the extruder (The ratio of screw effective length L and diameter D: L / D24, compression part screw temperature 190 degreeC, head temperature 200 degreeC) provided with the screw with a diameter of 40 mm. While melt-kneading the silane MB and the catalyst MB in this extruder, the 1 / 0.8 TA conductor was extrusion coated with a thickness of 1 mm to obtain a coated conductor having an outer diameter of 2.8 mm.
The resulting coated conductor is left in an environment at a temperature of 80 ° C. and a relative humidity of 95% for 24 hours to bring the extrusion coating of the coated conductor into contact with water to have a coating layer consisting of a heat resistant silane crosslinked resin molding The wire was manufactured.

<Test>
The following tests were evaluated about silane MB prepared above and the manufactured electric wire, and the result was shown in Table 1 and Table 2.
(Test 1: Extrudability test)
The preparation of silane MB was performed five times in the same manner as in each example. An extruder equipped with a screw having a diameter of 25 mmφ (ratio of screw effective length L to diameter D: L / D = 25, cylinder temperature 180 ° C., head temperature 190 ° C.) was used for the obtained silane MB. ) And extruded a sheet of 1 mm thick and about 8 mm wide.
With respect to the surface of the obtained sheet having a length of 50 cm, black spots due to burning and the presence or absence of appearance roughness were visually evaluated.
-Occurrence of black spots-
As for the presence or absence of black spots, those where black spots were not generated (confirmed) on all five sheets (confirmed) are "○", and black spots were generated (confirmed) on one of the five sheets (confirmed) Failed) was made into "x".
-Whether or not the appearance is rough-
In addition, those that did not generate (confirmed) at least one bump with a diameter of 1 mm or more in all the five sheets are regarded as “○”, and two out of five sheets have a bump with a diameter of 1 mm or more. The thing which was not generated (confirmed) at all (confirmed) is regarded as "Δ", and the one with a diameter of 1 mm or more was generated (confirmed) in all five sheets, and "×" did.

(Test 2: appearance rough test of electric wire)
About the electric wire manufactured by each Example and the comparative example, the presence or absence of the appearance roughening for 3 m in length was confirmed visually.
In the surface roughening test, those that could not generate (confirmed) bumps having a diameter of 1 mm or more (pass) are marked with “○”, and two to four bumps having a diameter of 1 mm or more were generated (confirmed) (pass) The product was evaluated as “Δ”, and 5 (or more) occurrences (confirmations) of bumps having a diameter of 1 mm or more were generated (confirmed) as “x”.

(Test 3: heat deformation characteristic test)
The heat distortion test was done as heat resistance of the electric wire (coating layer). The heating deformation test was conducted at a measurement temperature of 120 ° C. and a load of 5 N, using the electric wire as a test piece as it was, based on JIS C 3005. In the heat distortion test, the rate of reduction (%) in the thickness of the test specimen was 40% or less.
In the heat deformation property test, when the thickness reduction rate of the coating layer (heat-resistant silane cross-linked resin molded product) of the wire is 40% or less, the polyolefin resin is crosslinked via the silanol bond in the coating layer of the wire. It can be confirmed that the resulting resin contains a silane crosslinked resin.
Both of the comparative examples 2 and 5 have very poor appearances, and thus can not be subjected to the heat deformation property test, and are shown by “−” in Table 2.

From the results of Tables 1 and 2, the following can be understood.
The comparative example which prepared the silane crosslinking resin composition (sheet) by the manufacturing method which does not go through the process prescribed | regulated by this invention prepares the silane crosslinking resin composition from the organic peroxide in a Banbury mixer at the time of preparation (molding). It was confirmed that the generated radical acted on the silane coupling agent and a bursting sound was presumed to have reacted the silane coupling agent. Moreover, black spots or rough appearance were confirmed in the molded article (sheet) of the obtained silane crosslinkable resin composition. Moreover, it turns out that burning and rough appearance generate | occur | produce in the coating layer (silane crosslinked resin molded object) of a comparative example 1-5, and it is inferior to an external appearance.
On the other hand, in each of Examples 1 to 10 in which the heat-resistant silane-crosslinked resin molded product was produced by the production method of the present invention, the volatilization of the silane coupling agent is effectively suppressed to prevent burning and appearance roughening. Also, it has an excellent appearance (passing extrudability test and appearance rough test of electric wire), and furthermore, it shows excellent heat resistance of 40% or less in thickness reduction rate in the heat deformation test.

Claims (11)

The manufacturing method of the heat resistant silane crosslinked resin molded object which has following process (a)-(e).
Process (a): Process of melt-kneading a resin composition containing a polyolefin resin and 1 to 400 parts by mass of an inorganic filler with respect to 100 parts by mass of the resin composition: Process (b): Obtained in process (a) 0.01 to 0.6 parts by mass of an organic peroxide, and a graftable portion of the polyolefin resin with respect to 100 parts by mass of the resin composition in the molten and kneaded product Step (c) of mixing 0.5 to 15 parts by mass of a silane coupling agent having a site capable of grafting reaction at a temperature lower than the decomposition temperature of the organic peroxide: obtained in step (b) The mixture is melt-kneaded above the decomposition temperature of the organic peroxide in the absence of a silanol condensation catalyst, and a radical generated from the organic peroxide causes a graft reaction of the silane coupling agent on the polyolefin resin. Step (d) of preparing a silane masterbatch containing a silane graft resin, thereby forming the melt after kneading the silane masterbatch and the silanol condensation catalyst step (e): obtained in step (d) Contacting the molded body with water   The method for producing a heat-resistant silane cross-linked resin molded product according to claim 1, wherein the compounding amount of the inorganic filler is 1 to 80 parts by mass with respect to 100 parts by mass of the resin composition.   The polyolefin resin is ethylene-vinyl acetate copolymer, ethylene- (meth) acrylic acid copolymer, ethylene- (meth) acrylic acid alkyl copolymer, low density polyethylene, linear low density polyethylene, ultra low The method for producing a heat-resistant silane-crosslinked resin molded article according to claim 1 or 2, wherein the method comprises at least one resin selected from the group consisting of density polyethylene, ethylene rubber and styrenic elastomer.   The manufacturing method of the heat resistant silane crosslinked resin molded object of any one of Claims 1-3 in which the said polyolefin resin contains ethylene rubber.   The method for producing a heat-resistant silane-crosslinked resin molded product according to claim 4, wherein the ethylene rubber is ethylene-propylene-diene rubber or ethylene-propylene rubber.   The method for producing a heat-resistant silane-crosslinked resin molded product according to any one of claims 1 to 5, wherein the silane coupling agent is vinyltrimethoxysilane or vinyltriethoxysilane.   The inorganic filler is at least one selected from the group consisting of silica, aluminum hydroxide, magnesium hydroxide, calcium carbonate, antimony trioxide, clay, magnesium carbonate, zinc borate, zinc hydroxystannate and talc. The manufacturing method of the heat resistant silane crosslinked resin molded object of any one of -6.   The method for producing a heat-resistant silane-crosslinked resin molded product according to any one of claims 1 to 8, wherein the melt mixing in the step (c) is performed using an extrusion device.   The heat resistant product containing the heat resistant silane crosslinked resin molded object manufactured by the manufacturing method of the heat resistant silane crosslinked resin molded object of any one of Claims 1-8.   The heat resistant product according to claim 9, which is an electric wire or an optical fiber cable provided with a coating layer made of the heat resistant silane crosslinked resin molded product.   A heat-resistant silane-crosslinked resin molded article produced by the method of producing a heat-resistant resin molded article according to any one of claims 1 to 8, which is a silane formed by crosslinking a polyolefin-based resin via a silanol bond. Heat resistant silane crosslinked resin molded article containing crosslinked resin.