Silane-crosslinkable resin composition, silane-crosslinked resin molded article, their manufacturing method, and silane-crosslinked resin molded article

Abstract

To provide a silane crosslinkable resin composition which enables production of a silane crosslinked resin molding that exhibits high flowability in melting while containing a polybutene resin, has excellent appearance, is flexible and is excellent in high temperature characteristics, and a method for producing the same; the silane crosslinked resin molding and a method for producing the same; and a silane crosslinked resin molded product.SOLUTION: There are provided a silane crosslinkable resin composition which contains 100 pts.mass of a base resin containing 5-50 mass% of a polybutene resin, 1-30 mass% of an ethylene-α-olefin copolymer rubber, 5-40 mass% of a styrenic elastomer, and 5-40 mass% of mineral oil, a silane coupling agent grafted and coupled to the base resin, 0.5-50 pts.mass of an inorganic filler, and 0.01-0.5 pt.mass of a silanol condensation catalyst, and a method for producing the same; a silane crosslinked resin molding using the silane crosslinkable resin composition and a method for producing the same; and a silane crosslinked resin molded product containing the silane crosslinked resin molding.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a silane-crosslinkable resin composition, a silane-crosslinked resin molded article, a method for producing the same, and a silane-crosslinked resin molded article using the silane-crosslinked resin molded article. [Background technology]

[0002] Various (tubular) resin molded articles are used as coating layers for wiring materials such as insulated wires, cables, cords, optical fiber cores, and optical fiber cords (optical fiber cables) used in the fields of electrical and electronic equipment and industry, and as tubular bodies (sometimes referred to as water pipes) such as hoses or tubes for water supply or hot water supply (water supply, drainage). These resin molded articles are required to have properties according to their intended use. For example, the coating materials and tubular bodies are required to have appearance characteristics, flexibility, heat resistance, etc. Furthermore, the inner layer of a water pipe that comes into contact with tap water is required to be resistant to chlorine water. Polyolefin resins such as polyethylene resin and polypropylene resin are commonly used as materials for forming such resin molded articles. However, polybutene resin, which has excellent chlorine water resistance among polyolefin resins, is preferably used as a material for forming the coating layer, particularly for water pipes. However, although polybutene resin is amorphous immediately after molding, it undergoes a crystalline transition over time and eventually becomes a crystalline resin with a 1 / 3 helical structure. Therefore, resin moldings made from polybutene resin are generally hard and may not exhibit the required flexibility.

[0003] Resin molded articles (tap water tubular articles) that improve on the low flexibility caused by such rigid polybutene resins have been proposed. For example, Patent Document 1 describes a hose consisting of an inner layer tube having a polybutene resin layer or a cross-linked polyethylene resin layer as an inner layer that directly contacts hot water and water and a thermoplastic elastomer layer as an outer layer, and a reinforcing layer covering the outside. Furthermore, Patent Document 2 describes "a hot water hose having a four-layer structure consisting of, from the inside out, an inner layer, an intermediate layer, a reinforcing layer, and an outer layer, wherein the inner layer is a cross-linked polyethylene resin or a polybutene resin, the intermediate layer is a resin containing polypropylene resin and an ethylene-based elastomer and / or a styrene-based elastomer, the reinforcing layer is a braided layer or a spiral wound layer made of metal wire or synthetic fiber, and the outer layer is a resin containing polypropylene resin and an ethylene-based elastomer and / or a styrene-based elastomer." [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 9-178058 [Patent Document 2] Japanese Patent Application Laid-Open No. 2010-131875 Summary of the Invention [Problem to be solved by the invention]

[0005] The hoses described in Patent Documents 1 and 2 both improve the flexibility of the entire hose by providing a layer formed of a thermoplastic elastomer or the like on the outside of an inner layer formed of a polybutene resin. However, because the inner layer of these hoses is itself formed of a hard polybutene resin, there is still room for improvement in the flexibility of the entire hose.

[0006] Methods for molding a resin into a tubular shape include, for example, extrusion molding, in which a resin is extruded into a tubular shape, and spiral molding, in which a resin is extruded into a strand shape such as a tape, string, or sheet and then spirally wound. Furthermore, to further enhance pressure resistance, the resin may be reinforced with a hard resin (e.g., polypropylene-based resin, nylon resin, etc.). If the hard resin is formed into a strand shape and spirally molded together with a flexible tape-like resin, both pressure resistance and excellent flexibility can be achieved, making spiral molding a preferred method. However, polybutene resin is not suitable for spiral molding because it has poor melt fluidity compared to common polyolefin resins (e.g., polyethylene resin). Specifically, extruding polybutene resin into a tape-, string-, or sheet-like molded product (hereinafter sometimes referred to as a tape-like molded product) can easily result in poor appearance, such as residual flow marks, the generation of granular matter due to aggregates, and a rough appearance (the generation of undulations). Even if a tape-shaped molding could be formed while suppressing the occurrence of poor appearance, the tape-shaped moldings would not be fused with sufficient strength when spirally wound into a tubular body. Therefore, even if such a tubular molding maintains its shape at low temperatures, such as room temperature, it will undergo significant deformation at high temperatures, such as temperatures above 80°C, and in some cases, the fused portions of the spirally wound tape-shaped molding will peel off (detach) (become unable to maintain their shape), causing it to no longer function as a tubular molding. Because the hoses described in Patent Documents 1 and 2 have a multilayer structure, no consideration was given to manufacturing them by spiral molding, and as mentioned above, spiral molding is considered difficult for layers made of polybutene resin.

[0007] An object of the present invention is to solve the above problems and to provide a silane-crosslinkable resin composition that can be used to produce a silane-crosslinked resin molded article that contains a polybutene resin but exhibits high fluidity when melted, has excellent appearance, is flexible, and has excellent high-temperature properties that allow it to maintain its shape even in high-temperature environments, and a method for producing the same. Another object of the present invention is to provide a silane-crosslinked resin molded article that contains a polybutene resin but has excellent appearance, is flexible, and has excellent high-temperature properties, and a method for producing the silane-crosslinked resin molded article. A further object of the present invention is to provide a silane-crosslinked resin molded article using a silane-crosslinked resin molded article that exhibits the above-mentioned excellent properties. [Means for solving the problem]

[0008] The present inventors have discovered that a crosslinkable resin composition containing a polybutene resin as an essential component can be prepared by mixing (coexisting) ethylene-α-olefin copolymer rubber, a styrene-based elastomer, and a mineral oil in specific proportions to form a base resin, and then combining specific amounts of an inorganic filler and a silanol condensation catalyst to form a silane-crosslinkable resin composition. The inventors have also discovered that using this silane-crosslinkable resin composition as a material for producing silane-crosslinked resin molded articles can utilize the high fluidity and excellent moldability in the melt to produce flexible silane-crosslinked resin molded articles that have excellent appearance and high-temperature properties. Based on this finding, the inventors have conducted further research and have arrived at the present invention.

[0009] That is, the object of the present invention has been achieved by the following means. <1> A silane-crosslinkable resin composition comprising: 100 parts by mass of a base resin containing 5 to 50% by mass of polybutene resin, 1 to 30% by mass of ethylene-α-olefin copolymer rubber, 5 to 40% by mass of a styrene-based elastomer, and 5 to 40% by mass of mineral oil; a silane coupling agent graft-bonded to the base resin; 0.5 to 50 parts by mass of an inorganic filler; and 0.01 to 0.5 parts by mass of a silanol condensation catalyst. <2> The base resin contains 12 to 40 mass % of the polybutene resin. <1> The silane-crosslinkable resin composition according to claim 1. <3> The polybutene resin has a melt flow rate (190°C, 2.16 kg) of 0.3 to 2 g / 10 min. <1> or <2> The silane-crosslinkable resin composition according to claim 1. <4> The inorganic filler is at least one selected from metal hydrates, talc, clay, silica, calcium carbonate, and carbon black. <1> ~ <3> The silane-crosslinkable resin composition according to any one of the above. <5> The content of the silane coupling agent is 3 to 15 parts by mass relative to 100 parts by mass of the base resin. <1> ~ <4> The silane-crosslinkable resin composition according to any one of the above. <6> the above <1> ~ <5> 1. A silane-crosslinked resin molded article obtained by molding the silane-crosslinkable resin composition according to any one of claims 1 to 9 and then contacting it with water. <7> the above <6> A silane-crosslinked resin molded article comprising the silane-crosslinked resin molded article according to claim 1. <8> a hose or tube, <7> The silane-crosslinked resin molded article according to claim 1. <9> The hose or tube is <1> ~ <5> 1. A spiral molded article of the silane-crosslinkable resin composition according to claim 1, which is contacted with water. <8> The silane-crosslinked resin molded article according to claim 1.

[0010] <10> A method for producing a silane-crosslinkable resin composition, comprising: (1) melt-mixing 100 parts by mass of a base resin containing 5 to 50 mass% of a polybutene resin, 1 to 30 mass% of an ethylene-α-olefin copolymer rubber, 5 to 40 mass% of a styrene-based elastomer, and 5 to 40 mass% of a mineral oil with 0.5 to 50 parts by mass of an inorganic filler, 1 to 15 parts by mass of a silane coupling agent having a grafting reaction site capable of undergoing a grafting reaction with the base resin, 0.01 to 0.6 parts by mass of an organic peroxide, and 0.01 to 0.5 parts by mass of a silanol condensation catalyst to obtain a silane-crosslinkable resin composition, The method for producing a silane-crosslinkable resin composition, wherein the step (1) comprises the following steps (a) and (c), provided that when a part of the base resin is melt-mixed in the step (a), the method also comprises the following steps (a), (b), and (c): Step (a): Mixing all or a part of the base resin, the inorganic filler, and the silane cap The ring agent and the organic peroxide are heated at a temperature equal to or higher than the decomposition temperature of the organic peroxide. and melt-mixing the mixture to prepare a silane masterbatch. Step (b): Melt-mixing the remainder of the base resin with the silanol condensation catalyst to form a catalyst mixture. Preparing the star batch Step (c): Mixing the silane masterbatch with the silanol condensation catalyst or the catalyst masterbatch - A process of melt-mixing the batch <11> A method for producing a silane-crosslinked resin molded product, comprising the steps of: (1) above; (2) molding the silane-crosslinkable resin composition to obtain a molded product; and (3) contacting the molded product with water to obtain a silane-crosslinked resin molded product. <12> The step (2) of obtaining a molded body is a step of spiral molding the silane-crosslinkable resin composition to obtain a tubular molded body. <11> 1. A method for producing the silane-crosslinked resin molded article according to claim 1.

[0011] In the present invention, a numerical range expressed using "to" means a range that includes the numerical values ​​written before and after "to" as the lower and upper limits. In the present invention, when multiple numerical ranges are set for the content of a component, physical properties, etc., the upper and lower limits forming the numerical range are not limited to the specific combination written before and after "to" as a specific numerical range, but can be a numerical range obtained by appropriately combining the upper and lower limits of each numerical range. [Effects of the Invention]

[0012] The present invention provides a silane-crosslinkable resin composition that, despite containing a polybutene resin, exhibits high fluidity when melted and is capable of producing a silane-crosslinked resin molded article that has excellent appearance, flexibility, and excellent high-temperature properties, and a method for producing the same. The present invention also provides a silane-crosslinked resin molded article that, despite containing a polybutene resin, has excellent appearance, flexibility, and excellent high-temperature properties, and a method for producing the silane-crosslinked resin molded article. Furthermore, the present invention also provides a silane-crosslinked resin molded article that uses a silane-crosslinked resin molded article that exhibits the above-mentioned excellent properties. DETAILED DESCRIPTION OF THE INVENTION

[0013] [Silane-crosslinkable resin composition] The silane-crosslinkable resin composition of the present invention contains 100 parts by mass of a base resin containing 5 to 50 mass% polybutene resin, 1 to 30 mass% ethylene-α-olefin copolymer rubber, 5 to 40 mass% styrene elastomer, and 5 to 40 mass% mineral oil, a silane coupling agent grafted to the base resin, 0.5 to 50 mass parts of an inorganic filler, and 0.01 to 0.5 mass parts of a silanol condensation catalyst. This silane-crosslinkable resin composition can be prepared, for example, by the method for producing the silane-crosslinkable resin composition of the present invention, which will be described later. As will be described in detail below, the silane-crosslinkable resin composition of the present invention contains a silane-crosslinkable resin in which a silane coupling agent bonded or dissociated with an inorganic filler is grafted (grafted) to a base resin, particularly an ethylene-α-olefin copolymer rubber, and a decomposition product of a polybutene resin. This silane-crosslinkable resin composition exhibits high fluidity when molten, and can be used to produce a silane-crosslinked resin molded article exhibiting excellent properties, as described below, by a silane crosslinking method (silanol condensation reaction), while suppressing, for example, the volatilization of the silane coupling agent and the occurrence of poor appearance. Therefore, the silane-crosslinkable resin composition of the present invention is suitable for use in the method for producing a silane-crosslinked resin molded article of the present invention or the silane-crosslinked resin molded article of the present invention.

[0014] The reason why the silane-crosslinkable resin composition of the present invention exhibits the above-mentioned excellent properties is not yet clear, but is thought to be as follows. The silane-crosslinkable resin composition of the present invention contains polybutene resin as a polymer component constituting the base resin, and is also thought to contain decomposition products of the polybutene resin that are decomposed by radicals generated from organic peroxides during the grafting reaction of the silane coupling agent to the base resin, which is specific to the silane crosslinking method. In this way, by making the crosslinking form of the silane-crosslinkable resin composition silane crosslinkable, it is possible to make the decomposition products of the polybutene resin coexist (contain) in the composition, and it is thought that high fluidity can be achieved when melted. Here, examples of decomposition products of polybutene resin include low-molecular-weight (e.g., 10,000 or less) polybutene resins, alkenes such as pentene and hexene, etc. The content of polybutene resin in the silane-crosslinkable resin composition (base resin) refers to the total content of polybutene resin and its decomposition products, and is synonymous with the amount used in preparing the silane-crosslinkable resin composition (the content of polybutene resin in the base resin). The content of decomposition products in the silane-crosslinkable resin composition cannot be uniquely determined depending on the fluidity to be developed, but can be, for example, a value determined by the content of polybutene resin in the silane-crosslinkable resin composition (base resin) described below and the content of organic peroxide used in the grafting reaction described below.

[0015] The silane-crosslinkable resin composition of the present invention contains an ethylene-α-olefin copolymer rubber as a polymer component constituting the base resin. This allows a silane-crosslinked structure to be established in the ethylene-α-olefin copolymer rubber via a silane coupling agent, which is believed to cooperate with the polybutene resin (including decomposition products) and the styrene-based elastomer to form a silane-crosslinked resin molded article exhibiting the above-mentioned excellent properties. The silane-crosslinkable resin composition of the present invention also contains a styrene-based elastomer and a mineral oil as polymer components constituting the base resin. This is believed to enhance the flexibility of the silane-crosslinked resin molded article and suppress the occurrence of defective appearance. Furthermore, the silane-crosslinkable resin composition contains an inorganic filler, which allows the composition to exhibit excellent high-temperature properties without impairing flowability, flexibility, etc.

[0016] [Silane-crosslinked resin molded body] The silane-crosslinked resin molded article of the present invention is a crosslinked resin molded article (molded article made of a silanol condensate of the silane-crosslinkable resin composition) obtained by silane crosslinking (silanol condensation reaction) after molding the silane-crosslinkable resin composition of the present invention. The silane-crosslinked resin molded article of the present invention is flexible and highly flex-resistant, and exhibits an excellent appearance. Furthermore, because the silane-crosslinked structure is established not only at room temperature but also without any special crosslinking treatment, the amount of deformation is small even when a large tension is applied, for example, in the longitudinal direction, even in a high-temperature environment of, for example, 80 to 100°C, and the high-temperature properties (also referred to as heat resistance or temperature dependency) are excellent. As will be described in detail later, the silane-crosslinked resin molded article of the present invention has a crosslinked structure in which a base resin, usually an ethylene-α-olefin copolymer rubber, is silane-crosslinked (a crosslinked structure via a silane coupling agent or a silanol condensate thereof). As will be described later, an inorganic filler may be incorporated into this crosslinked structure. The silane-crosslinked resin molded article of the present invention is molded into an appropriate shape and size depending on the intended use, for example, the intended use of the silane-crosslinked resin molded article of the present invention described below.

[0017] Each component used in the present invention will be described below. One or more of each component can be used. In the present invention, the term "resin" is used to include elastomers and rubbers unless otherwise specified. <Base resin> The base resin used in the present invention contains, as essential polymer components, polybutene resin, ethylene-α-olefin copolymer rubber, styrene-based elastomer, and mineral oil. When the base resin contains these polymer components, it exhibits high fluidity when melted, and can form a silane-crosslinked resin molded article that has excellent appearance, high-temperature properties, and high flexibility. In addition to the above-mentioned essential polymer components, the base resin may contain any polymer component such as a polyolefin resin other than polybutene resin and other than ethylene-α-olefin copolymer rubber, as well as a rubber or elastomer such as a polymer that forms this polyolefin resin.

[0018] (Polybutene resin) Polybutene resins include 1-butene homopolymer or copolymer resins, such as highly stereoregular crystalline resins obtained by polymerizing high-purity butene-1 with a Ziegler catalyst. By combining polybutene resin with ethylene-α-olefin copolymer rubber, a styrene-based elastomer, and mineral oil in a silane crosslinking method, the silane crosslinkable resin composition can be made to exhibit high fluidity, and a silane crosslinked resin molded product can be formed that combines appearance, flexibility, and high-temperature properties. The copolymerization component capable of forming the polybutene resin may be any compound copolymerizable with 1-butene, such as a compound having an ethylenically unsaturated bond, and more specifically, an olefin compound other than 1-butene. The melt flow rate (MFR) of the polybutene resin is not particularly limited, but is preferably 0.3 to 2 g / 10 min, more preferably 0.8 to 2.0 g / 10 min, in terms of the fluidity of the silane-crosslinkable resin composition. In the present invention, the MFR of the polybutene resin refers to a value measured in accordance with Japanese Industrial Standards (JIS) K 7210-1 (2014) at a temperature of 190°C under a load of 2.16 kg. The polybutene resin may be synthesized as appropriate, or a commercially available product may be used, such as Viewlon (registered trademark) and Tafmer (registered trademark) manufactured by Mitsui Chemicals, Inc.

[0019] (Ethylene-α-olefin copolymer rubber) The ethylene-α-olefin copolymer rubber (also referred to as ethylene rubber in the present invention) is not particularly limited as long as it is a copolymer rubber obtained by copolymerizing ethylene and an α-olefin, and known rubbers can be used. The ethylene-α-olefin copolymer rubber has a grafting reactive site that undergoes a grafting reaction with the grafting reactive site of a silane coupling agent, and undergoes a grafting reaction with the silane coupling agent in the silane crosslinking method. Examples of the grafting reactive site include an unsaturated bond site in a carbon chain and a carbon atom containing a hydrogen atom. By using the ethylene-α-olefin copolymer rubber in combination with a polybutene resin, a styrene-based elastomer, and a mineral oil, a silane-crosslinkable resin composition can be formed, and a silane-crosslinked resin molded product that combines appearance, flexibility, and high-temperature properties can be formed. Examples of the ethylene-α-olefin copolymer rubber include a binary copolymer rubber of ethylene and an α-olefin, and a terpolymer rubber of ethylene, an α-olefin, and a diene compound. The α-olefin is not particularly limited, and an α-olefin having 3 to 12 carbon atoms is preferred. The diene compound constituting the terpolymer is not particularly limited, and examples thereof include conjugated diene compounds such as butadiene, isoprene, 1,3-pentadiene, and 2,3-dimethyl-1,3-butadiene, and non-conjugated diene compounds such as dicyclopentadiene (DCPD), ethylidene norbornene (ENB), and 1,4-hexadiene. Non-conjugated diene compounds are preferred. The binary copolymer rubber is preferably ethylene-propylene rubber (EPM), and the terpolymer rubber is preferably ethylene-propylene-diene rubber (EPDM).

[0020] (styrene elastomer) Styrenic elastomers are elastomers made from polymers containing components derived from aromatic vinyl compounds within the molecule. Using styrenic elastomers in combination with polybutene resin, ethylene-α-olefin copolymer rubber, and mineral oil can impart high fluidity to silane-crosslinkable resin compositions, resulting in uniform silane crosslinking structures and improved appearance and flexibility, particularly in silane-crosslinked resin molded articles. Examples of such styrenic elastomers include block copolymers and random copolymers of conjugated diene compounds and aromatic vinyl compounds, as well as hydrogenated versions of these copolymers. More specific examples include styrene-ethylene-butylene-styrene block copolymers (SEBS), styrene-isoprene-styrene block copolymers (SIS), hydrogenated SIS, styrene-butadiene-styrene block copolymers (SBS), hydrogenated SBS, styrene-ethylene-ethylene-propylene-styrene block copolymers (SEEPS), styrene-ethylene-propylene-styrene block copolymers (SEPS), styrene-butadiene rubber (SBR), and hydrogenated styrene-butadiene rubber (HSBR).

[0021] (mineral oil) The mineral oil may be any oil derived from petroleum, and examples include oils used as plasticizers for polyolefin resins or mineral oil softeners for rubber. The mineral oil softener is a mixed oil containing three components: an oil made of a hydrocarbon having an aromatic ring, an oil made of a hydrocarbon having a naphthenic ring, and an oil made of a hydrocarbon having a paraffin chain. By using a mineral oil in combination with a polybutene resin, an ethylene-α-olefin copolymer rubber, and a styrene-based elastomer, high fluidity can be imparted to the silane-crosslinkable resin composition, and in particular, the silane-crosslinked resin molded article can have a uniform silane crosslinked structure and improve its appearance and flexibility. Suitable mineral oils include paraffin oil and naphthenic oil, with paraffin oil being particularly preferred. It is particularly preferred that this mineral oil be incorporated together with the elastomer.

[0022] (Polyolefin resin) The polyolefin resin that can be contained in the base resin may be any polyolefin resin other than the above-mentioned polybutene resin and other than the above-mentioned ethylene-α-olefin copolymer rubber, and examples thereof include resins made of polymers obtained by homopolymerizing or copolymerizing olefin compounds, such as known resins used in resin compositions. Specific examples include polyethylene (PE), polypropylene (PP), and polyolefin copolymers containing an acid copolymer or an acid ester copolymer. Polyolefin resins are preferably polyethylene resins and polypropylene resins. The polyolefin resins may be acid-modified with commonly used unsaturated carboxylic acids or their derivatives.

[0023] The polyethylene resin (PE) is not particularly limited as long as it is a polymer resin whose main component is ethylene, and examples thereof include high-density polyethylene (HDPE), low-density polyethylene (LDPE), ultra-high molecular weight polyethylene (UHMW-PE), linear low-density polyethylene (LLDPE), and very low-density polyethylene (VLDPE). The MFR of the polyethylene resin is not particularly limited, but is preferably 0.1 to 10 g / 10 min, more preferably 1 to 5 g / 10 min, from the viewpoint of the fluidity of the silane-crosslinkable resin composition. In the present invention, the MFR of the polyethylene resin refers to a value measured in accordance with JIS K 7210-1 (2014) at a temperature of 190°C under a load of 2.16 kg.

[0024] The polypropylene resin (PP) is not particularly limited as long as it is a polymer resin whose main component is propylene, and examples thereof include propylene homopolymers, random polypropylenes, and block polypropylenes. The MFR of the polypropylene resin is not particularly limited, but is preferably 0.1 to 50 g / 10 min, more preferably 1 to 30 g / 10 min, from the viewpoint of the fluidity of the silane-crosslinkable resin composition. In the present invention, the MFR of the polypropylene resin refers to a value measured in accordance with JIS K 7210-1 (2014) at a temperature of 230°C under a load of 2.16 kg.

[0025] In the polyolefin copolymer resin having an acid copolymerization component or an acid ester copolymerization component, the compound from which the acid copolymerization component or the acid ester copolymerization component is derived is not particularly limited, and examples thereof include carboxylic acid compounds such as (meth)acrylic acid, and acid ester compounds such as vinyl acetate and alkyl (meth)acrylate. The alkyl group of the alkyl (meth)acrylate preferably has 1 to 12 carbon atoms. Examples of polyolefin copolymers having an acid copolymerization component or an acid ester copolymerization component include ethylene-vinyl acetate copolymer (EVA), ethylene-methyl acrylate copolymer (EMA), ethylene-ethyl acrylate copolymer (EEA), and ethylene-butyl acrylate copolymer (EBA).

[0026] (Base Resin Composition) The base resin contains the polymer components in the following contents so that the total is 100% by mass. When the base resin contains multiple polymer components, the content of the polymer component is the total content of the multiple polymer components. The content of polybutene resin in 100% by mass of the base resin is 5 to 50% by mass. When the content of polybutene resin is within this range, the fluidity of the silane-crosslinkable resin composition can be increased, and the appearance, flexibility, and high-temperature properties of the silane-crosslinked resin molded article can be improved. The content of polybutene resin is preferably 10 to 45% by mass, more preferably 12 to 40% by mass, and even more preferably 17 to 35% by mass, from the viewpoint of achieving a more highly balanced improvement in fluidity, appearance, flexibility, and high-temperature properties, and furthermore exhibiting high strength. The content of the ethylene-α-olefin copolymer rubber in 100% by mass of the base resin is 1 to 30% by mass. When the content of the ethylene-α-olefin copolymer rubber is within this range, the appearance, flexibility, and high-temperature properties of the silane-crosslinked resin molded article can be improved while maintaining the fluidity of the silane-crosslinkable resin composition. The content of the ethylene-α-olefin copolymer rubber is preferably 3 to 25% by mass, more preferably 5 to 20% by mass, in order to achieve a well-balanced improvement in the flexibility and high-temperature properties of the silane-crosslinked resin molded article by establishing a silane crosslinked structure while maintaining an excellent appearance.

[0027] The content of the styrene elastomer in 100% by mass of the base resin is 5 to 40% by mass. When the content of the styrene elastomer is within this range, the fluidity of the silane-crosslinkable resin composition can be increased, and the appearance, flexibility, and high-temperature properties of the silane-crosslinked resin molded article can be improved. The content of the styrene elastomer is preferably 7 to 35% by mass, and more preferably 10 to 30% by mass, in particular, from the viewpoint of further improving the fluidity, appearance, and flexibility. The mineral oil content is 5 to 40% by mass in 100% by mass of the base resin. When the mineral oil content is within this range, the fluidity of the silane-crosslinkable resin composition is increased, and the appearance, flexibility, and high-temperature properties of the silane-crosslinked resin molded article can be improved. The mineral oil content is preferably 7 to 35% by mass, and more preferably 10 to 30% by mass, in particular, from the viewpoint of further improving the fluidity, appearance, and flexibility. The total content of the styrene elastomer and the mineral oil in 100% by mass of the base resin is preferably 10 to 70% by mass, more preferably 15 to 60% by mass, and even more preferably 20 to 50% by mass, particularly from the viewpoint of improving fluidity and appearance.

[0028] The total content of the polyolefin resin in 100% by mass of the base resin is not particularly limited and may be determined appropriately, and is, for example, preferably 2 to 30% by mass, more preferably 3 to 25% by mass, and even more preferably 5 to 20% by mass. The content of polyethylene resin in 100% by mass of base resin is not particularly limited and can be appropriately set in consideration of the total content of the polyolefin resins, and is preferably 2 to 25% by mass, and more preferably 2.5 to 15% by mass. Similarly, the content of polypropylene resin in 100% by mass of base resin is not particularly limited and can be appropriately set in consideration of the total content of the polyolefin resins, and is preferably 2 to 25% by mass, and more preferably 5 to 20% by mass. The contents of ethylene-α-olefin copolymer and polyolefin copolymer resin having an acid copolymerization component or an acid ester copolymerization component in 100% by mass of base resin are not particularly limited and can be appropriately set in consideration of the total content of the polyolefin resins, and can be, for example, 0 to 20% by mass, respectively.

[0029] <Silane coupling agent> The silane-crosslinkable resin composition contains a silane coupling agent grafted to a base resin, particularly an ethylene-α-olefin copolymer rubber. The base resin grafted with the silane coupling agent is preferably prepared by a grafting reaction between the silane coupling agent and the base resin in step (a) described below. The silane coupling agent used in the present invention (before the grafting reaction) has a grafting reaction site (atom or functional group such as an ethylenically unsaturated group) that can undergo grafting reaction with the grafting reaction site of the base resin in the presence of radicals generated by the decomposition of the organic peroxide.In addition, it preferably has a hydrolyzable silyl group as a silanol condensation reaction site, and can react with the chemically bondable site of the inorganic filler.The silane coupling agent that can be used in the present invention is not particularly limited, and includes silane coupling agents used in conventional silane crosslinking methods. Suitable silane coupling agents include silane coupling agents having an ethylenically unsaturated group and a hydrolyzable silyl group, and specific examples thereof include vinylalkoxysilanes such as vinyltrimethoxysilane, vinyltriethoxysilane, vinyltributoxysilane, vinyldimethoxyethoxysilane, vinyldimethoxybutoxysilane, vinyldiethoxybutoxysilane, allyltrimethoxysilane, allyltriethoxysilane, and vinyltriacetoxysilane, and (meth)acryloxyalkoxysilanes such as methacryloxypropyltrimethoxysilane, methacryloxypropyltriethoxysilane, and methacryloxypropylmethyldimethoxysilane. Among these, vinyltrimethoxysilane or vinyltriethoxysilane is particularly preferred.

[0030] <Inorganic filler> The inorganic filler is not particularly limited, but is preferably one having a site on its surface that can chemically bond with the silanol condensable reactive site of the silane coupling agent by hydrogen bonding, covalent bonding, or intermolecular bonding. The site that can chemically bond with the reactive site of the silane coupling agent is not particularly limited, but examples thereof include OH groups (hydroxyl groups, water molecules of water of water or crystalline water, OH groups such as carboxyl groups), amino groups, and SH groups. Specific examples of inorganic fillers include metal hydrates such as compounds having hydroxyl groups or crystal water, such as aluminum hydroxide, magnesium hydroxide, boehmite, calcium carbonate, magnesium carbonate, calcium silicate, magnesium silicate, calcium oxide, magnesium oxide, aluminum oxide, aluminum nitride, aluminum borate, whiskers, hydrated aluminum silicate, hydrated magnesium silicate, basic magnesium carbonate, hydrotalcite, and talc. Other examples include boron nitride, silica (crystalline silica, amorphous silica, etc.), carbon black, clay (calcined clay), zinc oxide, tin oxide, titanium oxide, molybdenum oxide, silicone compounds, quartz, zinc borate, white carbon, zinc borate, zinc hydroxystannate, and zinc stannate. The inorganic filler preferably contains at least one of metal hydrates, talc, clay, silica, calcium carbonate, and carbon black. The inorganic filler may be a surface-treated inorganic filler that has been surface-treated with a silane coupling agent, etc. The amount of the surface treatment is not particularly limited, but is preferably, for example, 3 mass % or less.

[0031] <Silanol condensation catalyst> The silanol condensation catalyst functions to promote the condensation reaction of the silanol condensation-capable reactive sites of the silane coupling agent grafted onto the base resin in the presence of water, thereby crosslinking the base resin via the silane coupling agent. Such silanol condensation catalysts are not particularly limited and include, for example, organotin compounds, metal soaps, platinum compounds, etc. Examples of organotin compounds include dibutyltin dilaurate, dioctyltin dilaurate, dibutyltin dioctiate, dibutyltin diacetate, etc.

[0032] <Additives> In the present invention, various additives that are commonly used in resin compositions can also be used, such as antioxidants, lubricants, metal deactivators, plasticizers, flame retardants, flame retardant assistants, and (co)polymers other than those described for the base resin. Examples of the antioxidant include hindered phenol-based antioxidants, benzimidazole-based antioxidants, etc. Examples of the flame retardant (auxiliary) agent include bromine-based flame retardants and / or antimony trioxide.

[0033] <Organic peroxide> In the present invention, an organic peroxide is used in preparing the silane-crosslinkable resin composition. The organic peroxide generates radicals by thermal decomposition, thereby promoting the grafting reaction of the silane coupling agent to the base resin (a covalent bond-forming reaction between the grafting reaction site of the silane coupling agent and the graftable site of the base resin, also called a (radical) addition reaction), and also inducing the decomposition reaction of the polybutene resin. The organic peroxide is not particularly limited, and examples thereof include compounds represented by the general formula: R 1 -OO-R 2 , R 3 -OO-C(=O)R 4 , R 5 C(=O)-OO(C=O)R 6 Preferably, a compound represented by the formula: 1 ~R 6 Each independently represents an alkyl group, an aryl group, or an acyl group. 1 ~R 6 Among these, it is preferable that all of them are alkyl groups, or that one of them is an alkyl group and the other is an acyl group. The decomposition temperature of the organic peroxide is preferably 80 to 195°C, particularly preferably 125 to 180°C, as measured by the method described in JP-A-2016-121203. Examples of such organic peroxides include those described in paragraph

[0036] of JP 2016-121203 A, the contents of which are incorporated herein by reference. Among these, dicumyl peroxide, 2,5-dimethyl-2,5-di-(tert-butylperoxy)hexane (Perhexa 25B), and 2,5-dimethyl-2,5-di-(tert-butylperoxy)hexyne-3 are preferred.

[0034] (Composition of Silane-Crosslinkable Resin Composition) The content of the silane coupling agent grafted to the base resin in the silane cross-linkable resin composition (converted into the mass before the grafting reaction to the base resin) is not particularly limited, but from the viewpoint of suppressing the formation of protruding aggregates (gel particles) due to cross-linked gel, etc., and the evaporation of the silane coupling agent, and thereby enabling the production of a silane cross-linked resin molded product having an excellent appearance and a sufficient cross-linked structure, the content is preferably 1 to 15 parts by mass, more preferably 2 to 15 parts by mass, even more preferably 3 to 15 parts by mass, and particularly preferably 3 to 8 parts by mass, relative to 100 parts by mass of the base resin. The content of the inorganic filler in the silane-crosslinkable resin composition is 0.5 to 50 parts by mass, preferably 1 to 40 parts by mass, and more preferably 3 to 30 parts by mass, relative to 100 parts by mass of the base resin, in order to improve the flowability of the silane-crosslinkable resin composition and the flexibility and high-temperature properties of the silane-crosslinked resin molded product. The content of the silanol condensation catalyst in the silane crosslinkable resin composition is 0.01 to 0.5 parts by mass, preferably 0.03 to 0.2 parts by mass, and more preferably 0.05 to 0.15 parts by mass, per 100 parts by mass of the base resin, in order to achieve a good balance between appearance, flexibility, and high-temperature properties.

[0035] The total content of additives in the silane-crosslinkable resin composition is not particularly limited and can be appropriately set within a range that does not impair the effects of the present invention. For example, the content of antioxidant is not particularly limited, but is preferably 0.2 to 8 parts by mass, more preferably 0.5 to 5 parts by mass, per 100 parts by mass of the base resin.

[0036] (Composition of Silane-Crosslinked Resin Molded Product) Since the silane-crosslinked resin molded article is formed by molding a silane-crosslinkable resin composition and then contacting it with water to cause a silanol condensation reaction, the contents of the above-mentioned components in this molded article are usually the same as those in the silane-crosslinkable resin composition, except that in the silane-crosslinked resin molded article, the content of the silane coupling agent is the content before the silanol condensation reaction, and the content of the base resin is the content before crosslinking.

[0037] [Method of manufacturing silane-crosslinkable resin composition and silane-crosslinked resin molded article] The method for producing the silane-crosslinkable resin composition of the present invention and the method for producing the silane-crosslinked resin molded article of the present invention will be described below. The silane-crosslinkable resin composition of the present invention is produced by carrying out the following step (1), and the silane-crosslinked resin molded product of the present invention is produced by carrying out the following steps (1) to (3). The method for producing a silane-crosslinked resin molded article and the method for producing a silane-crosslinkable resin composition of the present invention may be collectively referred to as the production method of the present invention.

[0038] Step (1): 5 to 50 mass% of polybutene resin, 1 to 3 mass% of ethylene-α-olefin copolymer rubber 0 mass%, styrene elastomer 5 to 40 mass%, and mineral oil 5 to 0.5 to 40% by mass of inorganic filler per 100 parts by mass of base resin 50 parts by mass, 1 to 15 parts by mass of a silane coupling agent, and 0.5 parts by mass of an organic peroxide. 0.01 to 0.6 parts by mass of a silanol condensation catalyst and 0.01 to 0.5 parts by mass of a silanol condensation catalyst. A step of melt-mixing to obtain a silane-crosslinkable resin composition This step (1) includes the following steps (a) and (c), except that if a part of the base resin is melt-mixed in the following step (a), the step (1) also includes the following steps (a), (b), and (c). Step (a): Mixing all or part of the base resin, an inorganic filler, and a silane coupling agent and an organic peroxide are melt-mixed at a temperature equal to or higher than the decomposition temperature of the organic peroxide. and preparing a silane masterbatch. Step (b): Melt-mix the remainder of the base resin with the silanol condensation catalyst to form a catalyst masterbatch. - Preparation of the batch Step (c): Silane masterbatch and silanol condensation catalyst or catalyst masterbatch and a step of melt-mixing the Step (2): A step of molding the silane-crosslinkable resin composition to obtain a molded product. Step (3): A step of contacting the molded product with water to obtain a silane-crosslinked resin molded product.

[0039] In the production method of the present invention, the mixed amounts of each polymer component used as the base resin are the same as the above-described contents of the base resin composition, and the mixed amounts of the silane coupling agent, inorganic filler, silanol condensation catalyst, and additives are the same as the contents in the above-described silane-crosslinkable resin composition. In the production method of the present invention, when a portion of the base resin is mixed in step (a), the polymer component to be mixed may be a specific polymer component, or may be two or more polymer components. The proportion of the base resin to be mixed in step (a) is preferably 60 to 95 mass %, more preferably 70 to 85 mass %, of 100 mass % of the base resin to be mixed in steps (a) and (b). The remainder of the base resin (carrier resin) to be mixed in step (b) is determined appropriately depending on the portion of the base resin to be mixed in step (a).

[0040] However, in the production method of the present invention, the base resin used in step (a) contains at least a polybutene resin and an ethylene-α-olefin copolymer rubber among the above polymer components, which can increase the fluidity of the silane-crosslinkable resin composition and also establish a silane-crosslinked structure in the silane-crosslinked resin molded product (form an ethylene-α-olefin copolymer rubber to which a silane coupling agent is grafted). The amount of polybutene resin used in step (a) is not particularly limited, but from the viewpoint of fluidity, it is preferably 50% by mass or more, more preferably 75% by mass or more, and even more preferably 100% by mass (total amount) of the polybutene resin content in the base resin. The amount of ethylene-α-olefin copolymer rubber used in step (a) is not particularly limited, but in order to be able to construct a sufficient silane crosslinked structure without reducing fluidity, it is preferably 50% by mass or more, more preferably 70% by mass or more, and even more preferably 80% by mass or more, relative to the above content of ethylene-α-olefin copolymer rubber in the base resin.

[0041] In terms of improving the fluidity and appearance of the silane-crosslinked resin composition, it is preferable to use at least a portion of the styrene elastomer and mineral oil in step (a). The amounts of the styrene elastomer and mineral oil used in step (a) are not particularly limited, but are preferably 50% by mass or more, more preferably 70% by mass or more, and even more preferably 80% by mass or more, relative to their respective contents in the base resin. The total amount of the styrene elastomer and mineral oil used in step (a) is not particularly limited and can be determined within the same range as the above-mentioned respective amounts used.

[0042] Although a part of the inorganic filler can be used in step (b), it is preferable to use it in step (a), particularly from the viewpoint of improving high-temperature properties. When an inorganic filler is used in step (b), the amount used is not particularly limited and is determined appropriately.

[0043] The various additives may be mixed in either step (a) or step (b). The antioxidant may be mixed in either step (a) or step (b). However, mixing in step (b) is preferred because it allows the grafting reaction in step (a) to proceed efficiently.

[0044] The amount of organic peroxide mixed in step (a) is 0.01 to 0.6 parts by mass per 100 parts by mass of the base resin. Mixing the organic peroxide in the above amounts with the polybutene resin and ethylene-α-olefin copolymer rubber at the above contents allows for a balanced promotion of the decomposition reaction of the polybutene resin and the grafting reaction of the silane coupling agent onto the ethylene-α-olefin copolymer rubber during melt mixing, while also suppressing the formation of gel particles. As a result, the fluidity of the silane-crosslinkable resin composition is enhanced, while the appearance, flexibility, and high-temperature properties of the silane-crosslinked resin molded product are improved. The amount of organic peroxide mixed is preferably 0.1 to 0.2 parts by mass.

[0045] <Process (a)> Step (a) is a step of preparing a silane master batch (Silane MB) containing a silane cross-linkable resin in which the silane coupling agent is grafted onto the base resin and bonded to it by grafting, and a decomposition product of a polybutene resin, by subjecting a base resin and a silane coupling agent to a grafting reaction in the presence of an inorganic filler. In this step, the base resin is heated and mixed with the inorganic filler and the silane coupling agent in the presence of an organic peroxide at a temperature equal to or higher than the decomposition temperature of the organic peroxide, thereby obtaining Silane MB as a molten mixture.

[0046] In step (a), the mixing temperature for melt-mixing (also referred to as melt-kneading) the above-mentioned components is equal to or higher than the decomposition temperature of the organic peroxide, preferably equal to or higher than the decomposition temperature of the organic peroxide + (25 to 110)°C, more preferably 150 to 230°C, and even more preferably 175 to 210°C. Mixing conditions such as mixing time can be set appropriately. For example, the mixing time can be 1 to 25 minutes, preferably 3 to 20 minutes. By melt-mixing at a temperature equal to or higher than the decomposition temperature of the organic peroxide, the organic peroxide thermally decomposes to generate radicals, which progress the grafting reaction and the decomposition reaction of the polybutene resin.

[0047] The mixing method may be any method commonly used for mixing rubber, plastics, etc. The mixing apparatus may be, for example, a single-screw extruder, a twin-screw extruder, a roll, a Banbury mixer, or various kneaders, and is preferably an internal mixer such as a Banbury mixer or various kneaders.

[0048] In the present invention, the order of mixing is not limited, and the above components may be mixed in any order. For example, the above components may be melt-mixed all at once. In the production method of the present invention, the step (a) is preferably carried out by the following steps (a-1) and (a-2) in the following mixing order. Step (a-1): A step of mixing an inorganic filler and a silane coupling agent to prepare a mixture. Process Step (a-2): The mixture obtained in step (a-1) and a part of the base resin are mixed with an organic peroxide. The mixture is melted and mixed in the presence of an organic peroxide at a temperature above the decomposition temperature of the organic peroxide. Process

[0049] In step (a-1), premixing the inorganic filler and silane coupling agent allows for a well-balanced formation of silane coupling agent weakly bonded or adsorbed to the inorganic filler and silane coupling agent strongly bonded or adsorbed to the inorganic filler. This effectively prevents volatilization of the silane coupling agent and condensation reactions between unadsorbed silane coupling agents during melt mixing in step (a-2). As a result, silane-crosslinked resin molded articles can be produced that exhibit superior appearance and further improve the mechanical properties (tensile strength) and heat resistance inherent to the silane crosslinking method. Examples of weak bonds with the inorganic filler include hydrogen bond interactions, ionic, partial charge, or dipole interactions, and adsorption. Examples of strong bonds with the inorganic filler include chemical bonds with sites on the inorganic filler surface that can be chemically bonded.

[0050] The mixing method and conditions for step (a-1) are not particularly limited, but examples include a method and conditions in which a known mixer is used to mix the components by dry or wet mixing, typically at a temperature below the decomposition temperature of the organic peroxide, preferably 10 to 60°C, more preferably around room temperature (20 to 25°C), for several minutes to several hours. Of these, dry mixing at a temperature below the decomposition temperature of the organic peroxide is preferred. Other conditions for dry mixing are determined appropriately.

[0051] In step (a-1), a base resin can also be mixed as long as the temperature is maintained below the decomposition temperature. The organic peroxide may be present during the melt mixing in step (a-2), and may be mixed in step (a-2), but is preferably mixed in step (a-1).

[0052] Next, the mixture obtained in step (a-1) and a portion of the base resin are melt-mixed in the presence of an organic peroxide at a temperature equal to or higher than the decomposition temperature of the organic peroxide to prepare a silane masterbatch (step (a-2)). This produces a silane masterbatch containing decomposition products of the silane crosslinkable resin and polybutene resin. The melt-mixing in this step prevents excessive crosslinking between the base resins (the formation of gel particles) while suppressing the volatilization and self-condensation of the silane coupling agent. The melt-mixing method and conditions for this step (a-2) are not particularly limited, and the melt-mixing method and conditions for the above step (a) can be applied.

[0053] In step (a-2), at least the following modes are conceivable as the mode in which the silane coupling agent undergoes a grafting reaction with the base resin. That is, a mode in which the silane coupling agent weakly bonded to or adsorbed on the inorganic filler is detached from the inorganic filler and undergoes a grafting reaction with the base resin. The crosslinked structure formed in step (3) described below from this mode does not incorporate the inorganic filler, and is typically a crosslinked structure mediated by a silanol condensate between silane coupling agents. Alternatively, a mode in which the silane coupling agent strongly bonded to or adsorbed on the inorganic filler undergoes a grafting reaction with the resin while maintaining its bond or adsorption to the inorganic filler. The crosslinked structure formed in step (3) described below from this mode incorporates the inorganic filler, and is a crosslinked structure originating from the inorganic filler via the silane coupling agent bonded to it.

[0054] In step (a), antioxidants, additives, etc. may also be mixed. However, it is preferable that a silanol condensation catalyst is not substantially mixed in step (a). This can suppress the silanol condensation reaction of the silane coupling agent. In the present invention, "substantially not mixed" does not exclude the unavoidably present silanol condensation catalyst, but means that it may be present in an amount that can suppress the silanol condensation reaction, for example, in an amount of 0.01 parts by mass or less per 100 parts by mass of the base resin.

[0055] The Silane MB prepared in step (a) contains a reaction mixture of a base resin, an inorganic filler, and a silane coupling agent, and contains a silane crosslinkable resin (silane graft polymer) in which the silane coupling agent is grafted to the base resin to an extent that it can be molded in step (b) described below. The silane coupling agent grafted to the base resin includes those bound or adsorbed to the inorganic filler at their silanol condensation-capable reactive sites. The MFR of Silane MB is not particularly limited, but from the viewpoint of the fluidity of the silane-crosslinkable resin composition, it is preferably 0.3 g / 10 min or more, more preferably 0.3 to 20 g / 10 min, and even more preferably 0.8 to 15 g / 10 min. In the present invention, the MFR of Silane MB refers to a value measured in accordance with JIS K 7210-1 (2014) at a temperature of 190°C under a load of 2.16 kg. Silane MB is preferably in pellet or powder form.

[0056] <Process (b)> In the production method of the present invention, the remainder of the base resin and a silanol condensation catalyst are melt-mixed to prepare a catalyst masterbatch (catalyst MB). The melt-mixing method and conditions in step (b) are not particularly limited, and the melt-mixing method and conditions in step (a) can be applied. For example, the melt-mixing temperature may be equal to or higher than the melting temperature of the base resin, and is preferably 120 to 200°C, more preferably 140 to 180°C. The catalyst MB is preferably in the form of pellets or powder.

[0057] <Process (c)> In the production method of the present invention, the silane master batch and the silanol condensation catalyst or catalyst master batch are then melt-mixed. Preferably, the silane MB and catalyst MB are melt-mixed. The mixing method is not particularly limited, but is basically the same as the melt-mixing in step (a), and mixing is carried out at a temperature at which at least the base resin melts. The mixing conditions in step (c) are not particularly limited, and the mixing conditions in step (a) above can be applied. For example, the mixing temperature is appropriately selected depending on the base resin, and is preferably 80 to 250°C, more preferably 100 to 240°C, and even more preferably 120 to 200°C. In the melt-mixing step (c), a melt-mixing method and conditions are set that can maintain the fluidity (moldability) of the silane-crosslinkable resin composition. The silane-crosslinkable resin in the silane-crosslinkable resin composition is an uncrosslinked product in which the silane coupling agent has not undergone silanol condensation. In practice, when melt-mixing is performed in step (c), partial crosslinking is unavoidable, but the moldability of the resulting silane-crosslinkable resin composition is maintained. For example, to prevent the occurrence or progression of the silanol condensation reaction, it is preferable that the mixture of silane MB and silanol condensation catalyst is not kept at a high temperature for a long period of time. In step (c), it is preferable to dry-blend the silane MB and the silanol condensation catalyst or catalyst masterbatch before melt-mixing them. The method and conditions for dry-blending are not particularly limited, and examples thereof include the dry-blending and conditions used in step (a-1).

[0058] In this manner, the silane-crosslinkable resin composition of the present invention is produced. This silane crosslinkable resin composition contains a silane crosslinkable resin, a decomposition product of a polybutene resin, an inorganic filler, a silanol condensation catalyst, etc. In this silane crosslinkable resin, the silane coupling agent's reactive site capable of silanol condensation may be bonded to or adsorbed on the inorganic filler, but is not silanol condensed. Therefore, the silane crosslinkable resin includes a silane crosslinkable resin in which the silane coupling agent bonded to or adsorbed on the inorganic filler is grafted to the base resin, and a silane crosslinkable resin in which the silane coupling agent not bonded to or adsorbed on the inorganic filler is grafted to the base resin.

[0059] <Process (2)> In the method for producing a silane-crosslinked resin molded article of the present invention, the silane-crosslinkable resin composition is then molded to obtain a molded article. The molding method is not particularly limited and is appropriately selected depending on the shape of the desired product. Examples of molding methods include extrusion molding using an extruder, extrusion molding using an injection molding machine, molding using other molding machines, and spiral molding, which will be described later. When producing a wiring material, extrusion molding is preferred in terms of productivity and the ability to co-extrude with a conductor, while when producing a tubular molded product, spiral molding is preferred in terms of productivity, flexibility, and piping properties. Details of the spiral molding method will be described later, but it usually refers to a method in which a silane-crosslinkable resin composition is molded into a tape, string, sheet, or the like, and then this tape-shaped molded product is spirally wound to form a tubular shape. The molding conditions (melt-mixing conditions) are not particularly limited as long as they allow uniform mixing and molding and do not cause a silanol condensation reaction in the silane-crosslinkable resin composition of the present invention. For example, the melt-mixing method and conditions of step (c) can be applied.

[0060] Step (2) can be carried out simultaneously with or consecutively to step (c). For example, a series of steps can be employed in which silane MB and catalyst MB are dry-blended immediately before or within the coating device (extruder), then melt-mixed in the coating device (step (c)), and then molded (co-extrusion) onto the outer surface of a conductor or the like.

[0061] <Process (3)> In the method for producing a silane-crosslinked resin molded article of the present invention, the molded article obtained in step (2) is then brought into contact with water to produce a silane-crosslinked resin molded article. Because the molded article obtained in step (2) is an uncrosslinked article, this step initiates and advances (accelerates) a silanol condensation reaction at the silanol condensable reactive sites of the silane coupling agent grafted to the base resin, ultimately resulting in silane crosslinking. The uncrosslinked molded article can be brought into contact with water by a conventional method. The silanol condensation reaction proceeds simply by leaving the molded article at room temperature, for example, at a temperature of about 20 to 25°C. However, it is preferable to actively bring the molded article into contact with water to promote the silanol condensation reaction (crosslinking reaction). Examples of the contact method include methods (conditions) commonly used in silane crosslinking methods, such as immersion in warm water, placement in a moist heat bath, and exposure to high-temperature steam.

[0062] In this manner, the silane-crosslinked resin molded article of the present invention is produced. This silane-crosslinked resin molded article contains a crosslinked resin formed by condensation of a base resin (especially an ethylene-α-olefin copolymer rubber) via a siloxane bond, and a decomposition product of a polybutene resin. The silane-crosslinked resin molded article also contains an inorganic filler, which may be bonded to a silane coupling agent of the crosslinked resin. Therefore, the crosslinked resin is considered to include a crosslinked resin formed by bonding (crosslinking) multiple base resins to the inorganic filler via the silane coupling agent, resulting in the inorganic filler and the silane coupling agent being bonded or adsorbed thereto, and a crosslinked resin formed by crosslinking via the silane coupling agent (siloxane bond) (without the inorganic filler being involved) as a result of hydrolysis of the hydrolyzable groups of the silane coupling agent grafted to the base resin and undergoing a silanol condensation reaction with each other.

[0063] In the production method of the present invention, in step (a), the decomposition reaction of the polybutene resin and the grafting reaction of the silane coupling agent can be promoted while suppressing the volatilization and self-condensation reaction of the silane coupling agent, as well as the crosslinking reaction between base resins. Therefore, the silane-crosslinkable resin composition of the present invention exhibits good fluidity, and a flexible silane-crosslinked resin molded article having excellent appearance and high-temperature properties can be produced.

[0064] [Silane cross-linked resin molded products] The silane-crosslinked resin molded article of the present invention is a product containing the silane-crosslinked resin molded article of the present invention, and includes various resin molded articles. Examples include coating materials for insulated electric wires, cables, or optical fiber cables, rubber-substitute electric wire and cable materials, heat-resistant parts for microwave ovens or gas ranges, heat-resistant electric wire components, heat-resistant sheets, heat-resistant films, etc. Other examples include power plugs, connectors, sleeves, boxes, tape substrates, tubes, sheets, packing, cushioning materials, vibration-proofing materials, wiring materials used for internal and external wiring of electric and electronic devices, particularly electric wires and optical fiber cables, and the above-mentioned wiring materials and tubular molded articles. The silane-crosslinked resin molded article of the present invention may be a molded article that contains the silane-crosslinked resin molded article of the present invention in a part thereof (resin molded part), or may be a molded article consisting solely of the silane-crosslinked resin molded article of the present invention. The silane-crosslinked resin molded article of the present invention, like the silane-crosslinked resin molded article of the present invention, is flexible and highly flex-resistant, and exhibits excellent appearance and high-temperature properties. Furthermore, the spirally molded silane-crosslinked resin molded article is resistant to peeling at the fused portions of the tape-shaped molded article, even in high-temperature environments, and can maintain its functionality as a molded article. Taking advantage of these properties, the silane-crosslinked resin molded article of the present invention is preferably made into wiring materials or tubular molded articles, more preferably into tubular molded articles for water supply, and even more preferably into tubular molded articles for hot water supply (e.g., heat-resistant up to 100°C).

[0065] A wiring material and a tubular molded article that are preferable as the silane-crosslinked resin molded article of the present invention will now be described. <Wiring material> Examples of wiring materials include wiring materials having a coating layer on the outer periphery of a conductor, and wiring materials in which this coating layer is formed from the silane-crosslinked resin molded product of the present invention by molding the silane-crosslinkable resin composition of the present invention into an annular layer and crosslinking it. The wiring material is the same as conventional wiring materials used in various electrical and electronic equipment fields and industrial fields, except that the coating layer is formed from the silane-crosslinked resin shaped product of the present invention. The coating layer formed from the silane-crosslinked resin shaped product of the present invention is provided on the outer surface of the conductor directly or via another layer. The presence or absence of other layers and the materials thereof are appropriately determined depending on the type, application, required characteristics, etc. of the wiring material. Conventional conductors can be used, such as copper or aluminum single wires or stranded wires (wires in which tensile strength fibers are longitudinally attached or twisted). In addition to bare wires, tin-plated wires and wires with enamel-coated insulating layers can also be used. The thickness of the coating layer formed from the silane-crosslinked resin shaped product of the present invention is not particularly limited, but is usually about 0.15 to 5 mm. The wiring material of the present invention can be produced by molding by various molding methods in the above step (2) and then contacting with water. Preferably, it can be produced by disposing the silane-crosslinkable resin composition of the present invention in a ring shape around the conductor and then causing a crosslinking reaction (silanol condensation reaction). For example, in the above-mentioned method for producing a silane-crosslinked resin molded article of the present invention, the molding step (2) can be changed to a step of co-extrusion molding the silane-crosslinkable resin composition around the conductor using a coating device (extruder). Specific examples of co-extrusion molding are as described above.

[0066] <Tubular molded body> The tubular molded article is not particularly limited as long as it has a tubular structure, and examples thereof include various hoses and tubes. In terms of utilizing the above-mentioned excellent properties, the tubular molded article is preferably a hose or tube for water supply, particularly hot water supply. The tubular molded article may have a single-layer structure consisting of only a constituent layer formed from the silane-crosslinked resin molded article of the present invention, or a multi-layer structure comprising this constituent layer and a layer formed from another material. Examples of layers formed from other materials include various layers typically applied to tubular molded articles, such as a reinforcing layer, a surface layer, and layers described in the above-mentioned patent documents. When the silane-crosslinkable resin composition of the present invention is used to produce a tubular molded article, it is possible to produce a single-layer constituent layer (tubular molded article) that exhibits high flexibility despite containing a polybutene resin. This eliminates the need for a multi-layer structure to achieve flexibility as described in the above-mentioned patent documents, thereby reducing production efficiency and production costs. The tubular molded body (constituent layer) produced by the spiral molding method is a silanol condensate (silane crosslinked body) obtained by bringing a spiral molded body of the silane crosslinkable resin composition of the present invention into contact with water to cause a silanol condensation reaction (silane crosslinking), and typically, a seam (fused portion) formed by fusing the silane crosslinkable resin composition of the present invention remains in a spiral shape as a molding trace. The outer diameter, inner diameter, diameter difference (wall thickness), and length of the entire tubular molded product are not particularly limited and are determined appropriately depending on the application, etc. For example, the outer diameter can be 2 to 100 mm, the inner diameter can be 1 to 80 mm, the diameter difference can be 0.5 to 10 mm, and the length can be 0.1 to 100 m. The outer diameter, inner diameter, diameter difference (wall thickness), and length of the tubular molded product (constituent layer) formed from the silane-crosslinked resin molded product of the present invention can also be determined appropriately. For example, the outer diameter can be 1.5 to 90 mm, the inner diameter can be 1 to 80 mm, the diameter difference can be 0.25 to 5 mm, and the length can be 0.1 to 100 m.

[0067] The tubular molded product can be produced by various molding methods in step (2) above. A preferred method involves molding the silane-crosslinkable resin composition of the present invention into a tape, string, or sheet shape by various molding methods (preferably extrusion molding), then spirally winding the tape-shaped molded product to form a tubular body (corresponding to step (2) above), and finally contacting the tape-shaped molded product with water to produce a tubular molded product (corresponding to step (3) above). In the spiral molding method, the edges of the tape-shaped molded product are overlapped during spiral winding to fuse the tape-shaped molded product in the width direction. The overlapping amount (width) is not particularly limited as long as it provides sufficient fusion strength and can be determined appropriately. For example, it can be 0.5 to 30 mm. The silane-crosslinkable resin composition of the present invention has excellent fluidity and can be rapidly molded into a tape-shaped molded product (while maintaining its melt temperature), so the overlapping edges spontaneously fuse together due to the internal heat of the tape-shaped molded product (the heating temperature during melt molding). Therefore, by using the silane-crosslinkable resin composition of the present invention, it is possible to produce a tubular molded article that is firmly fused by spiral molding, even if it contains a hard polybutene resin that is not suitable for spiral molding. Conventional spiral molding methods, such as those using a hose manufacturing device with a hose molding shaft that can rotate and feed a tape-shaped molded article while spirally winding it, can be applied. The spiral molding conditions can be appropriately determined depending on the application, etc., and, for example, the winding pitch can be 10 to 150 mm. The conditions for molding the tape-shaped molded article are set so that the silane-crosslinkable resin composition of the present invention does not undergo a silanol condensation reaction. [Example]

[0068] The present invention will be described in more detail below based on examples, but the present invention is not limited to these examples.

[0069] The compounds used in the examples and comparative examples are shown below. <Base resin> (1) Polybutene resin: Viewlon (registered trademark) P5050N (trade name, MFR (190°C, 2.16 kg) 0.5 g / 10 min, manufactured by Mitsui Chemicals, Inc.) (2) Polybutene resin: TAFMER (registered trademark) BL4000 (trade name, MFR (190°C, 2.16 kg) 1.8 g / 10 min, manufactured by Mitsui Chemicals, Inc.) (3) Linear low-density polyethylene resin: Sumikathen CU5003 (trade name, MFR (190°C, 2.16 kg) 0.4 g / 10 min, manufactured by Sumitomo Chemical Co., Ltd.) (4) Linear low-density polyethylene resin: Evolue SP1071C (trade name, MFR (190°C, 2.16 kg) 10 g / 10 min, manufactured by Prime Polymer Co., Ltd.) (5) Linear low-density polyethylene: Evolue SP0540 (trade name, MFR (190°C, 2.16 kg) 3.8 g / 10 min, manufactured by Prime Polymer Co., Ltd.) (6) Polypropylene resin: PB222A (trade name, random PP, MFR (230°C, 2.16 kg) 0.8 g / 10 min, manufactured by SunAllomer Co., Ltd.) (7) Polypropylene resin: PM921V (trade name, random PP, MFR (230°C, 2.16 kg) 25 g / 10 min, manufactured by SunAllomer Co., Ltd.) (8) Polypropylene resin: PM940M (trade name, random PP, MFR (230°C, 2.16 kg) 30 g / 10 min, manufactured by SunAllomer Co., Ltd.) (9) Ethylene-α-olefin rubber: Nordel 4770P (trade name, EPDM, manufactured by Dow) (10) Ethylene-α-olefin rubber: EPT3092PM (trade name, EPDM, manufactured by Mitsui Chemicals, Inc.) (11) Styrene-based elastomer: Tuftec N504 (trade name, SEBS, manufactured by Asahi Kasei Corporation) (12) Mineral oil: Cosmo Neutral 500 (trade name, paraffin oil, manufactured by Cosmo Oil Lubricants Co., Ltd.)

[0070] <Inorganic filler> (1) Inorganic filler: Softon 1200 (product name, calcium carbonate, manufactured by Bihoku Funka Kogyo Co., Ltd.) (2) Inorganic filler: Aerosil 200 (product name, silica, manufactured by Nippon Aerosil Co., Ltd.)

[0071] <Silane coupling agent> KBM-1003: Product name, vinyltrimethoxysilane, manufactured by Shin-Etsu Chemical Co., Ltd. <Silanol condensation catalyst> ADK STAB OT-1: Product name, dioctyltin dilaurate, manufactured by ADEKA Corporation <Organic peroxide> Perhexa 25B: Trade name, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, decomposition temperature 154°C, manufactured by NOF Corporation

[0072] <Antioxidants> (1) Irganox 1076 (trade name, hindered phenolic antioxidant, manufactured by BASF) (2) Irganox MD1024 (trade name, hindered phenolic antioxidant (metal deactivator), manufactured by BASF)

[0073] (Examples 1 to 11 and Comparative Examples 1 to 10) Examples 1 to 11 and Comparative Examples 1 to 10 were carried out using the components shown in Tables 1 and 2, respectively. In Tables 1 and 2, the numerical values ​​relating to the blending amount (content) of each example are in parts by mass unless otherwise specified. Furthermore, blank spaces for each component mean that the blending amount of the corresponding component is 0 parts by mass. In each example and comparative example, a part of the base resin (specifically, the polymer component shown in the "Catalyst MB" column in Tables 1 and 2) was used as a carrier resin for catalyst MB in the mass ratio shown in the same column.

[0074] First, the inorganic filler, silane coupling agent, and organic peroxide were added to a rotary blade mixer (Mazera PM, product name, manufactured by Mazera Co., Ltd.) in the mass ratio shown in the "Silane MB" column of Tables 1 and 2, and stirred (premixed) at room temperature (25°C) at 10 rpm for 1 minute (step (a-1)). Thus, a powder mixture was obtained. Next, the powder mixture and the polymer components (base resins) shown in the "Silane MB" column of Tables 1 and 2 were added to a kneader (75 L capacity) preheated to 100°C in the weight ratios shown in the same column. The mixture was mixed at 40 rpm for 5 minutes, followed by a final melt-mixing step at 30 rpm for 3 minutes. After confirming that the resin temperature (mixture temperature) had reached 180-200°C, above the decomposition temperature of the organic peroxide, the molten mixture was pelletized using a feeder-ruder and pelletizer to obtain Silane MB (step (a-2), step (a-1), and step (a)).

[0075] Separately, the polymer component (carrier resin), antioxidant, and silanol condensation catalyst were sequentially charged into a kneader (75 L capacity) preheated to 80°C in the mass ratios shown in the "Catalyst MB" column of Tables 1 and 2, and mixed at 30 rpm for 5 minutes, followed by finish kneading (melt mixing) at 25 rpm for 3 minutes. After the resin temperature (mixture temperature) reached approximately 160°C and it was confirmed that the carrier resin was fully melted, the mixture was pelletized using a feeder-ruder and pelletizer to obtain Catalyst MB (step (b)).

[0076] Next, the pellets of Silane MB and Catalyst MB were dry-blended in a tumbler mixer at room temperature (25°C) for 2 minutes just before extrusion to obtain a dry blend (step (c) dry-blending step). The mixing ratio of Silane MB to Catalyst MB was the mass ratio shown in the "Silane MB" and "Catalyst MB" columns in Tables 1 and 2.

[0077] Using each of the prepared dry blends, a tape-shaped molded product and a tubular molded product were produced as follows. (1) Production of tape-shaped molded body (crosslinked body) A 25mm (screw diameter) extruder with an L / D (ratio of effective screw length L to diameter D) of 25 was used. The die head temperature was set at 180°C. The cylinder section was divided into three zones toward the feeder side, with extrusion temperatures set at C3 = 180°C, C2 = 170°C, and C1 = 150°C. The dry blend obtained in step (c) above was introduced into the extruder and melt-mixed at a screw rotation speed of 20 rpm (the melt-mixing step of step (c)). A 2mm-thick tape-shaped molded product (uncrosslinked product) was extruded (step (2)). The dry blend was melt-mixed in the extruder prior to extrusion to prepare a silane-crosslinkable resin composition. The obtained tape-shaped molded product (uncrosslinked product) was left to stand for 24 hours in an atmosphere at a temperature of 60°C and a humidity of 95% RH to bring the silane-crosslinkable resin composition into contact with water (step (3)). In this manner, tape-shaped molded articles (crosslinked articles) formed from silane-crosslinked resin molded articles were produced.

[0078] (2) Manufacturing of tape-shaped fusion-molded products (crosslinked products) In the same manner as in the production of the tape-shaped molded product (crosslinked product) described above (1), a 2 mm thick tape-shaped molded product (uncrosslinked product) was extruded (step (2)), and two tape-shaped molded products were sampled immediately after being extruded from the die outlet of the extruder without being cooled. The longitudinal ends of each tape-shaped molded product were then overlapped by 10 mm and placed on a hot plate preheated to 180°C, and a 725 gf weight preheated to 180°C was placed on top of the overlapping ends. In this state, the ends were heated at 180°C for 30 seconds to fuse together, yielding a tape-shaped fused molded product (uncrosslinked product). This fusion of the ends simulated the fusion that occurs during spiral molding. The obtained tape-shaped fusion-molded product (uncrosslinked product) was cooled at room temperature (25°C) for 24 hours, and then punched out into a No. 3 dumbbell shape as described in JIS K 6251 (2017) so that the fusion-bonded portion was at the center reference point. The No. 3 dumbbell test piece was then left to stand for 24 hours in an atmosphere at a temperature of 60°C and a humidity of 95% RH to bring the silane-crosslinkable resin composition into contact with water (step (3)). In this manner, tape-shaped fusion-bonded molded articles (crosslinked articles) formed from silane-crosslinked resin molded articles were produced.

[0079] The prepared Silane MB, the produced tape-shaped molded body (crosslinked body, corresponding to a silane-crosslinked resin molded body) and the produced tape-shaped fused molded body (crosslinked body, corresponding to a silane-crosslinked resin molded product) were evaluated as follows, and the results are shown in Tables 1 and 2.

[0080] <Silane MB MFR measurement> The MFR of each of the silane MBs prepared in Examples 1 to 11 and Comparative Examples 1 to 10 was measured in accordance with JIS K 7210-1 (2014) at a temperature of 190°C under a load of 2.16 kg. When the MFR (190°C, 2.16 kg) of Silane MB is 0.3 g / 10 min or more, the silane-crosslinkable resin composition prepared using this Silane MB will have excellent fluidity. It should be noted that under the above-mentioned measurement conditions for MFR, the silane-crosslinked resin composition undergoes a silanol condensation reaction, making it impossible to measure MFR. Therefore, this test is a test for alternatively evaluating the fluidity of the silane-crosslinkable resin composition using Silane MB.

[0081] <Appearance characteristics (extrusion appearance test)> The appearance characteristics of the tape-shaped molded product (crosslinked product) were visually inspected. As a result, if the appearance (surface) was smooth and no gel particles were visible, it was rated as "A" (good appearance, passed), and if significant flow marks, gel particles, roughness, etc. were visible on the surface, it was rated as "D" (poor appearance, failed).

[0082] <Hardness (Shore A hardness) measurement> The Shore A hardness of each tape-shaped molded product (crosslinked product) was measured in accordance with JIS K 6253-3 (2012). Specifically, a hardness meter was pressed into a sample made of three overlapping tape-shaped molded products with a thickness of 6 mm, and the value was measured after 15 seconds. The Shore A hardness is a test for evaluating the flexibility (hardness) of a silane crosslinked resin molded article, and a Shore A hardness of 85 or less is considered to be flexible and excellent in bending resistance (passing).

[0083] <Measurement of tensile strength> Each tape-shaped molded product (crosslinked product) was punched out into a No. 3 dumbbell-shaped test piece as specified in JIS K 6251 (2017). Using this test piece, the tensile strength (MPa) was measured in accordance with JIS C 3005 under conditions of a gauge length of 20 mm and a tensile speed of 200 mm / min. The tensile strength measurement is a reference test that assumes the scratch resistance of wiring materials (insulated wires), and a strength of 6 MPa or more is considered to pass.

[0084] <Hot set test> A 450gf (44.1N / cm) was applied to the bottom of a No. 3 dumbbell test piece, which was a tape-shaped fusion molded product (crosslinked product). 2 The hose was hung vertically with a weight of 10 kgf (38.8 cm) attached and left for 30 minutes in a temperature environment of 100°C, 105°C, 110°C or 115°C. The weight was applied to a hose (outer diameter 48 mm, inner diameter 38 mm, pitch 10 mm, silane cross-linked resin pipe wall thickness 2 mm) with a weight of 10 kgf (38.8 cm). 2 ) weight is attached. After 30 minutes had passed (load removal), the gauge length of the No. 3 dumbbell test piece was measured. As a result, if the gauge length portion (fused portion) of the No. 3 dumbbell test piece did not peel off and the gauge length of the No. 3 dumbbell test piece was within 175% of the gauge length before the test (before applying load: initial gauge length) (the gauge length extended by 2.75 times or less), it was deemed to have passed, and if the gauge length peeled off or the gauge length exceeded 175% of the gauge length before the test, it was deemed to have failed. In Tables 1 and 2, the measured gauge length (%) is expressed as a numerical value, and if the gauge length peeled off, it is indicated by "x". This test is a test to evaluate high-temperature properties as well as spiral molding applicability (spontaneous fusion), and it is sufficient if the material passes the test after being left in a temperature environment of 100°C for 30 minutes. Tests in temperatures of 105°C or higher are considered reference tests, and it is preferable to pass tests in higher temperature environments exceeding 100°C.

[0085] [Table 1]

[0086] [Table 2]

[0087] As is clear from the results in Tables 1 and 2, Comparative Examples 1 and 2, which contain no polybutene resin but contain a silane-crosslinkable polyethylene resin, have too low fluidity for the silane-crosslinkable resin composition, regardless of the MFR of the polyethylene resin contained, and in the hot set test, the fused portion of the tape-shaped fusion-molded article peels off, resulting in poor high-temperature properties. Comparative Examples 3 to 5, which contain no polybutene resin but contain a polypropylene resin that is difficult to silane-crosslink, show good fluidity, but are poor in either flexibility or appearance depending on the MFR of the polypropylene resin contained. In addition, Comparative Example 6, which does not contain ethylene-α-olefin copolymer rubber, has a tape-shaped fusion-molded article that is too stretched (too deformed), resulting in poor high-temperature properties. This is thought to be due to the insufficient construction of the silane crosslinked structure. On the other hand, Comparative Example 7, which contains an excess of ethylene-α-olefin copolymer rubber, has excellent high-temperature properties, but poor appearance due to the significant generation of gel particles. Furthermore, Comparative Example 8, which contains too little styrene elastomer and mineral oil, is poor in appearance and flexibility. This is thought to be due to the poor uniformity of the silane crosslinked structure. In Comparative Example 9, which does not contain inorganic filler, the tape-shaped fusion-molded article is too stretched (too deformed) and has poor high-temperature properties, whereas in Comparative Example 10, which contains an excessive amount of inorganic filler, the fluidity is too low and the hardness and tensile strength do not pass the standards.

[0088] In contrast, in Examples 1 to 11, which contain polybutene resin, ethylene-α-olefin copolymer rubber, styrene-based elastomer, mineral oil, inorganic filler, and silanol condensation catalyst in specific proportions, the silane-crosslinkable resin composition has high fluidity and is excellent in appearance, flexibility, and high-temperature properties. Thus, the silane-crosslinkable resin composition of the present invention exhibits high fluidity when melted and has excellent (extrusion) moldability. Furthermore, when a molded (uncrosslinked) body of the silane-crosslinkable resin composition is spirally molded, both ends of the molded body can be quickly fused, and the silane-crosslinked resin molded body itself exhibits excellent flexibility. Therefore, it can be seen that the silane-crosslinkable resin composition of the present invention can be used to produce a silane-crosslinked resin molded article that is flexible and has excellent flex resistance. This silane-crosslinked resin molded article is resistant to peeling at the fused portions, and even without special crosslinking treatment, the amount of deformation can be kept small even when a large tension is applied in a high-temperature environment of 100°C.

Claims

1. A silane-crosslinkable resin composition comprising: 100 parts by mass of a base resin containing 5 to 50% by mass of polybutene resin, 1 to 30% by mass of ethylene-α-olefin copolymer rubber, 5 to 40% by mass of a styrene-based elastomer, and 5 to 40% by mass of mineral oil (wherein the total content of the polybutene resin, the ethylene-α-olefin copolymer rubber, the styrene-based elastomer, and the mineral oil is 75% by mass or more); a silane coupling agent graft-bonded to the base resin; 0.5 to 50 parts by mass of an inorganic filler; and 0.01 to 0.5 parts by mass of a silanol condensation catalyst.

2. 2. The silane-crosslinkable resin composition according to claim 1, wherein the base resin contains 12 to 40% by mass of the polybutene resin.

3. 3. The silane-crosslinkable resin composition according to claim 1, wherein the polybutene resin has a melt flow rate (190°C, 2.16 kg) of 0.3 to 2 g / 10 min.

4. The silane-crosslinkable resin composition according to any one of claims 1 to 3, wherein the inorganic filler is at least one selected from silica and calcium carbonate.

5. The silane-crosslinkable resin composition according to any one of claims 1 to 4, wherein the content of the silane coupling agent is 3 to 15 parts by mass per 100 parts by mass of the base resin.

6. A silane-crosslinked resin molded article obtained by molding the silane-crosslinkable resin composition according to any one of claims 1 to 5 and then contacting it with water.

7. A silane-crosslinked resin molded article comprising the silane-crosslinked resin molded article according to claim 6.

8. The silane-crosslinked resin molded article according to claim 7, which is a hose or a tube.

9. 9. The silane-crosslinked resin molded article according to claim 8, wherein the hose or tube is obtained by contacting a spiral molded article of the silane-crosslinkable resin composition according to any one of claims 1 to 5 with water.

10. 1. A method for producing a silane-crosslinkable resin composition, comprising: a step (1) of melt-mixing 100 parts by mass of a base resin containing 5 to 50% by mass of a polybutene resin, 1 to 30% by mass of an ethylene-α-olefin copolymer rubber, 5 to 40% by mass of a styrene-based elastomer, and 5 to 40% by mass of a mineral oil (wherein the total content of the polybutene resin, the ethylene-α-olefin copolymer rubber, the styrene-based elastomer, and the mineral oil is 75% by mass or more); 0.5 to 50 parts by mass of an inorganic filler; 1 to 15 parts by mass of a silane coupling agent having a grafting reaction site capable of undergoing a grafting reaction with the base resin; 0.01 to 0.6 parts by mass of an organic peroxide; and 0.01 to 0.5 parts by mass of a silanol condensation catalyst to obtain a silane-crosslinkable resin composition; The method for producing a silane-crosslinkable resin composition, wherein the step (1) comprises the following steps (a) and (c), provided that when a part of the base resin is melt-mixed in the following step (a), the method also comprises the following steps (a), (b), and (c). Step (a): Mixing all or a part of the base resin, the inorganic filler, and the silane cap The ring agent and the organic peroxide are heated at a temperature equal to or higher than the decomposition temperature of the organic peroxide. and melt-mixing the mixture to prepare a silane masterbatch. Step (b): The remainder of the base resin and the silanol condensation catalyst are melt-mixed to form a catalyst mixture. Preparing the star batch Step (c): Mixing the silane masterbatch with the silanol condensation catalyst or the catalyst masterbatch - A process of melt-mixing the batch

11. A method for producing a silane-crosslinked resin molded body, comprising the step (1) described in claim 10, a step (2) of molding the silane-crosslinkable resin composition to obtain a molded body, and a step (3) of contacting the molded body with water to obtain a silane-crosslinked resin molded body.

12. The method for producing a silane-crosslinked resin molded article according to claim 11, wherein the step (2) of obtaining the molded article is a step of spiral molding the silane-crosslinkable resin composition to obtain a tubular molded article.

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