Crosslinkable resin composition, crosslinked resin composition, resin molded article, and resin composition kit

Abstract

The present invention provides a crosslinkable resin composition that can rapidly carry out a crosslinking reaction while relaxing restrictions on the polymer and the material to be crosslinked, a resin molded article containing the crosslinkable resin composition, and a resin composition kit suitably used when preparing the crosslinkable resin composition. [Solution] A crosslinkable resin composition comprising a base resin containing a polymer having at least one of a hydroxyl group and a hydroxyl group precursor, and a boron compound, wherein the content of boron atoms per 100 parts by mass of the base resin is 0.019 parts by mass or more; a crosslinkable resin composition and a resin molded article containing the same; and a resin composition kit comprising a first agent containing a polymer having at least one of a hydroxyl group and a hydroxyl group precursor, and a second agent containing a boron compound.

Description

[Technical Field]

[0001] The present invention relates to a crosslinkable resin composition, a crosslinked resin composition, a resin molded article, and a resin composition kit. [Background technology]

[0002] High mechanical properties and chemical resistance are required for wiring materials such as insulated wires, cables, cords, optical fiber cores, or optical fiber cords (optical fiber cables) used in the fields of electrical and electronic equipment and industrial applications. To achieve this, the resin composition that forms the insulating layer of the wiring material is subjected to a crosslinking treatment. For example, methods for crosslinking a resin composition containing polyolefin resins such as polyethylene include electron beam crosslinking, which involves irradiating the resin composition with an electron beam to cause crosslinking; organic peroxide crosslinking, which involves heating the resin composition after molding to decompose organic peroxides and cause a crosslinking reaction; and silane crosslinking, which involves using a silane coupling agent to crosslink the resin composition.

[0003] Electron beam crosslinking requires special crosslinking equipment such as electron beam generators, which require a significant amount of energy. Furthermore, thin-walled materials are desirable for the crosslinking reaction to proceed sufficiently. Organic peroxide crosslinking uses polymers with glass transition temperatures below the reaction temperature (decomposition temperature) of the organic peroxide, limiting the types of polymers that can be used. On the other hand, silane crosslinking has advantages such as not requiring the special equipment needed for electron beam crosslinking and allowing the crosslinking reaction to be carried out at low energy, and is therefore used in a wide range of fields, including wiring materials (for example, Patent Documents 1 and 2). [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Patent No. 2802274 specification [Patent Document 2] Japanese Patent Publication No. 2001-101928 [Overview of the Initiative] [Problems that the invention aims to solve]

[0005] Incidentally, in silane crosslinking, as described in Patent Documents 1 and 2, a silanol condensation catalyst such as an organotin compound is usually used to promote the hydrolysis reaction and silanol condensation reaction of the alkoxysilyl group of the silane coupling agent. However, as mentioned above, silane crosslinking involves the sequential occurrence and progression of the hydrolysis reaction and silanol condensation reaction, so it takes time for the crosslinking reaction to proceed and be completed until sufficient mechanical strength and other properties are exhibited. In particular, the time required for the crosslinking reaction to be completed increases as the thickness of the object to be crosslinked (uncrosslinked molded article) increases. Thus, although the silane crosslinking method has many advantages over electron beam crosslinking and organic peroxide crosslinking methods, it takes time for the crosslinking reaction to be completed and there are some limitations on the thickness of the object to be crosslinked.

[0006] In recent years, the applications of crosslinked molded products have expanded and diversified, and there has been growing interest in improving productivity and reducing environmental impact. As a result, various crosslinking methods, including the silane crosslinking method, are required to shorten the crosslinking reaction time and to relax or eliminate restrictions on polymer types and crosslinking targets. Furthermore, organotin compounds, which are commonly used as silanol condensation catalysts in the silane crosslinking method, are a cause for concern regarding their impact on the environment and human health, and it is desirable to avoid their use. However, Patent Documents 1 and 2 do not examine the silane crosslinking method from the perspective described above.

[0007] The present invention aims to provide a crosslinkable resin composition that can rapidly carry out a crosslinking reaction while relaxing the constraints on the polymer and crosslinking target used, and a resin composition kit suitably used in preparing this crosslinkable resin composition. Furthermore, the present invention aims to provide a crosslinkable resin composition obtained by crosslinking the crosslinkable resin composition, and a resin molded article containing the same. [Means for solving the problem]

[0008] The inventors of the present invention diligently studied methods for crosslinking resin compositions and discovered that, for crosslinkable resin compositions, by using a boron compound in combination with a base resin containing a polymer having a hydroxyl group or a group convertible to a hydroxyl group (hydroxyl group precursor), and setting the boron atom content to a specific amount, the crosslinking reaction via the hydroxyl group proceeds rapidly regardless of the type of polymer used. Furthermore, they found that this crosslinking reaction proceeds rapidly without being affected by the shape or thickness of the object to be crosslinked (when crosslinking the crosslinkable resin composition). Based on this finding, the inventors conducted further studies and arrived at the present invention.

[0009] In other words, the objectives of the present invention were achieved by the following means. <1> A crosslinkable resin composition comprising a base resin containing a polymer having at least one hydroxyl group and a hydroxyl group precursor, and a boron compound, A crosslinkable resin composition having a boron atom content of 0.019 parts by mass or more per 100 parts by mass of the base resin. <2> The boron compound has a BO bond. <1> The crosslinkable resin composition described above. <3> The boron compound is one of boric acid, boronic acid, and borate. <1> or <2> The crosslinkable resin composition described above. <4> The polymer includes a structure derived from a silane coupling agent. <1> ~ <3> A crosslinkable resin composition according to any one of the items. <5> The silane coupling agent has an alkoxysilyl group. <4> The crosslinkable resin composition described above. <6> the above <1> ~ <5> A crosslinked resin composition obtained by crosslinking a crosslinkable resin composition according to any one of the items described in the paragraph. <7> Having a BO bond, <6> The crosslinked resin composition described above. <8> the above <6> or <7> A resin molded article containing the crosslinked resin composition described above. <9> A resin composition kit comprising a first agent containing a polymer having at least one hydroxyl group and a hydroxyl group precursor, and a second agent containing a boron compound. [Effects of the Invention]

[0010] The present invention provides a crosslinkable resin composition that can rapidly carry out a crosslinking reaction while relaxing the constraints on the polymer and crosslinking target used, and a resin composition kit suitably used when preparing this crosslinkable resin composition. Furthermore, the present invention provides a crosslinkable resin composition obtained by crosslinking the crosslinkable resin composition, and a resin molded article containing the same. [Modes for carrying out the invention]

[0011] In the present invention, when describing the content, physical properties, etc. of components by indicating numerical ranges, if the upper and lower limits of the numerical range are described separately, either upper or lower limit can be appropriately combined to form a specific numerical range. On the other hand, when multiple numerical ranges represented by "~" are set and described, the upper and lower limits forming the numerical range are not limited to a specific combination of the upper and lower limits written before and after "~" as a specific numerical range, but can be a numerical range formed by appropriately combining the upper and lower limits of each numerical range. In the present invention, a numerical range represented by "~" means a range that includes the numbers written before and after "~" as the lower and upper limits. Furthermore, in this invention, "(meth)acrylic" refers to either acrylic or methacrylic, or both. For example, "(meth)acrylic acid ester" refers to either acrylic acid ester or methacrylic acid ester, or both.

[0012] [[Crosslinkable resin composition]] The crosslinkable resin composition of the present invention contains a base resin comprising a polymer having at least one of a hydroxyl group and a hydroxyl group precursor, and a boron compound, wherein the content of boron atoms is 0.019 parts by mass or more per 100 parts by mass of the base resin. In the crosslinkable resin composition of the present invention, a crosslinking reaction of a polymer having at least one of a hydroxyl group and a hydroxyl group precursor (also referred to as a crosslinkable polymer in the present invention) rapidly occurs and proceeds during melt kneading, and the crosslinking reaction is completed, for example, within 6 hours (preferably within 1 hour) after the end of melt kneading. In the present invention, when a wiring material having a coating layer formed using the crosslinkable resin composition of the present invention is continuously manufactured, for example, by winding it up on a winding machine, the time required for the crosslinking reaction to be completed can be the time described above, but it is also desirable to use the time until the material is wound up on the winding machine as the time required for the crosslinking reaction to be completed.

[0013] In the present invention, the starting point of "after melt mixing is completed" refers to the point in time when the crosslinkable resin composition of the present invention has been melt-mixed for the minimum time necessary to prepare a uniform composition. The minimum time necessary is not uniquely determined, depending on the performance and capacity of the melt mixer, the composition of the crosslinkable resin composition of the present invention, etc. Furthermore, "completion of the crosslinking reaction" means that the gel fraction G1 within 6 hours after the end of melt mixing (or until winding in the preferred embodiment described above) reaches a value that approximates the theoretical maximum value (also called the saturation value) of the gel fraction calculated based on the amount of hydroxyl groups, etc., of the crosslinkable polymer and the amount of boron compound used. Specifically, as shown in the examples described later, this means that the gel fraction G1 reaches a value equivalent to 90% of the gel fraction G2 after 7 days have elapsed since the end of melt mixing. The environment during the 7-day period is not particularly limited, but it should be either the humid heat conditions or atmospheric conditions adopted in Example A described later. In the present invention, the gel fraction ratio [(G1 / G2) × 100] is preferably 95% or higher, and more preferably 98% or higher. Ideally, the upper limit of this ratio should be 100%. Here, the "theoretical maximum value of the gel fraction" can be calculated as appropriate, but it can also be the same as the gel fraction G2 after 7 days have elapsed since the end of melt mixing. In the present invention, the gel fractions G1 and G2 are not uniquely defined by the abundance of groups such as hydroxy groups in the crosslinkable polymer and the amount of the boron compound used, respectively. For example, the gel fraction G1 is preferably 50% or more, more preferably 60% or more. The gel fraction G2 is preferably 50% or more, more preferably 60% or more. In the present invention, the gel fraction is a value measured by the method described in the Examples mentioned later. In the present invention, the crosslinking reaction progresses during melt kneading, and the crosslinking reaction may be almost completed during melt kneading. The progress and completion of the crosslinking reaction during melt kneading can be easily confirmed by an increase in kneading load (torque during kneading).

[0014] In the crosslinkable resin composition of the present invention, the content of boron atoms is 0.019 parts by mass or more based on 100 parts by mass of the base resin described later. When boron atoms are contained in this content, rapid crosslinking reaction of the crosslinkable resin composition (crosslinkable polymer) of the present invention can be achieved. The content of boron atoms in the crosslinkable resin composition of the present invention is preferably 0.086 parts by mass or more, more preferably 0.171 parts by mass or more, based on 100 parts by mass of the base resin, from the viewpoint that rapid crosslinking reaction of the crosslinkable resin composition of the present invention can be achieved, the gel fraction is improved, and excellent mechanical properties can be realized. On the other hand, the upper limit of the boron atom content is not particularly limited, but from the viewpoint of balancing rapid crosslinking reaction and excellent mechanical properties, it is preferably 2.85 parts by mass or less, more preferably 1.71 parts by mass or less, and still more preferably 0.494 parts by mass or less, based on 100 parts by mass of the base resin. In the present invention, the content of boron atoms in the crosslinkable resin composition is the content of boron atoms derived from the boron compound described below, and does not include the content of boron atoms derived from inorganic fillers or the like. In addition, the content of boron atoms in the crosslinkable resin composition, as long as the boron atoms are derived from a boron compound regardless of their existing state, is the sum of the contents of all boron atoms derived from the boron compound. Therefore, the content of boron atoms includes the content of boron atoms in independently (free) existing boron compounds (such as unreacted and undecomposed boron compounds) in the composition, and also includes the content of boron atoms when they are incorporated into the crosslinked structure as described later. The content of boron atoms in the crosslinkable resin composition of the present invention can be measured by conventional methods. For example, it can be measured by mass spectrometry, or from the abundance ratio of elements present on the sample surface by energy dispersive X-ray analysis using a scanning electron microscope or a transmission electron microscope. It can also be calculated from the blending amount during the preparation of the crosslinkable resin composition.

[0015] [[Crosslinked Resin Composition]] The crosslinked resin composition of the present invention is a crosslinked product obtained by subjecting the crosslinkable resin composition of the present invention to a crosslinking reaction treatment. The crosslinked resin composition of the present invention may be in a shapeless (unmolded) bulk state, or may be in a molded state (resin molded article). In the present invention, the term "crosslinked product" is generally used to include both crosslinked products in bulk state and crosslinked products in molded state. However, when distinguishing a crosslinked product in molded state from a crosslinked product in bulk state, it is simply referred to as a resin molded article or a crosslinked resin molded article.

[0016] The crosslinked resin composition of the present invention contains a crosslinked polymer having a crosslinked structure formed by a crosslinking reaction of a hydroxyl group or hydroxyl group precursor of a crosslinkable polymer. While the specific chemical structure of the crosslinked structure of the crosslinked resin composition and crosslinked polymer of the present invention, other than that formed by a crosslinking reaction of a hydroxyl group or hydroxyl group precursor, is not yet clear, it is presumed to have a structure formed by the reaction of a hydroxyl group or hydroxyl group precursor with a boron compound, for example, a -BO- bond. In particular, if the crosslinkable polymer is a silane graft polymer with a silane coupling agent grafted onto it (described later), it is presumed to have a structure derived from a silanol condensation-capable reaction site of the silane coupling agent, for example, a structure formed by the reaction of a hydroxyl group (-Si-OH group) with a boron compound (-Si-OB-), and further a structure containing residues derived from the grafting reaction site of the silane coupling agent (-grafting reaction site residue-Si-OB-), for example, one or more of the crosslinked structures shown below. The crosslinked resin composition having this crosslinked structure can also be called a boron crosslinked resin composition or a boron-silicon crosslinked resin composition.

[0017] In the example of the crosslinked structure below, the large wavy lines above and below represent the main chain of the polymer, and the small wavy lines bonded to the Si atom represent the linking group that connects the main chain of the polymer to the Si atom. This linking group is a residue derived from the grafting reaction site of the silane coupling agent, for example, -CH2-CH2-. In the example below, a hydroxyl group is bonded to the Si atom, but depending on the type of boron compound used, it may also be an alkyl or aryloxy group, and it may also undergo a silanol condensation reaction with other nearby silanol groups to form a -Si-O-Si- bond, or it may be bonded to an inorganic filler, etc.

[0018] [ka]

[0019] The gel fraction in the crosslinked resin composition of the present invention is at least the same as the gel fraction G1 described above, and preferably the same as the gel fraction G2 described above. In the crosslinked resin composition of the present invention, depending on the amount of hydroxyl groups and other components of the crosslinkable polymer and the amount of boron compound used, the boron compound may not participate in the crosslinking reaction and may remain in the crosslinked resin composition as a compound.

[0020] [[The resin molded article of the present invention]] The resin molded article of the present invention is a resin molded article containing the crosslinked resin composition of the present invention, and is typically a crosslinked resin molded article obtained by molding the crosslinked resin composition of the present invention into a predetermined shape and dimensions. The resin molded article of the present invention is molded into an appropriate shape and dimensions depending on the application, etc. The resin molded article of the present invention is the same as the crosslinked resin composition of the present invention except that it is molded into a predetermined shape and dimensions.

[0021] The resin molded article of the present invention is a resin molded article (including semi-finished products, parts, and components) containing the crosslinked resin composition of the present invention, and can be used as various molded articles. The resin molded article of the present invention may be a resin molded article that contains the crosslinked resin composition of the present invention in part (the resin molded portion), or it may be a resin molded article consisting only of the crosslinked resin composition of the present invention. The resin molded articles of the present invention are not particularly limited in size or shape, and can be various molded articles such as insulated wires, cables, optical cords, power plugs, connectors, sleeves, boxes, tape substrates, tubes, and sheets. The resin molded articles of the present invention are preferably used as coating layers for wiring materials such as insulated wires, cables, and optical cords. The thickness of the coating layer is not particularly limited, but is preferably 0.15 to 3 mm. The coating layer may have a multilayer structure. Wiring materials such as insulated wires and cables can be manufactured by extruding the crosslinkable resin composition of the present invention or a crosslinkable resin composition around conductors, optical fibers, bundled insulated wires, and other molded articles using a conventional extrusion molding machine. The coating layer formed with the crosslinkable resin composition of the present invention has a crosslinked structure (BO bond) containing boron atoms, as described above, and preferably has a silane crosslinked structure (-Si-OB- bond) via boron atoms. The crosslinkable resin composition, crosslinkable resin composition, and resin molded articles of the present invention used to form the coating layer of wiring materials are referred to as the crosslinkable resin composition for coating, the crosslinkable resin composition for coating, and the resin molded article for coating, respectively.

[0022] [[Resin Composition Kit]] The resin composition kit of the present invention is a kit of agents used to prepare the crosslinkable resin composition of the present invention, comprising a first agent (main agent) containing a polymer having at least one of a hydroxyl group and a hydroxyl group precursor, and a second agent (crosslinking agent) containing a boron compound. The first agent may contain, in addition to the polymer described above, other polymers, inorganic fillers, plasticizer components, additives, etc., as described later. However, it is preferable that it does not contain boron compounds and / or silanol condensation catalysts. The second agent may contain a boron compound as described later, and may also contain other polymers, inorganic fillers, silanol condensation catalysts, plasticizer components, additives, solvents for dissolving the boron compound, etc., as described later. Preferably, the second agent is an agent containing a boron compound alone, or an agent containing a boron compound and other polymers. The content of each component in the first and second agents is not particularly limited and can be determined as appropriate, for example, to the content of each component in the crosslinkable resin composition described later. The resin composition kit of the present invention may also have a third agent containing at least one of the following: other polymers, inorganic fillers, plasticizer components, additives, etc.

[0023] The resin composition kit of the present invention can be used to prepare the crosslinkable resin composition of the present invention by appropriately determining the amounts of the first agent and the second agent to be used, taking into consideration the content of boron atoms in the crosslinkable resin composition and the content of boron compounds in the crosslinkable resin composition described later.

[0024] The components used in this invention are described below. Each component may be used in one or more forms.

[0025] [Base resin] The base resin used in the present invention may contain a polymer having at least one of a hydroxyl group and a hydroxyl group precursor (a crosslinkable polymer), and may also contain polymers other than this crosslinkable polymer (referred to as other polymers). The crosslinkable polymer may be a polymer having at least one of a hydroxyl group and a hydroxyl group precursor (which may be conveniently referred to as a "hydroxypolymer" in this invention), or it may be a polymer having at least one of a hydroxyl group and a hydroxyl group precursor as a substituent or modifying group (which may be conveniently referred to as a "modified polymer" in this invention). The crosslinkable polymer is preferably a modified polymer in terms of handling ease and mechanical properties of the crosslinkable resin composition, and more preferably contains a structure derived from the silane coupling agent described later, i.e., a silane graft polymer described later.

[0026] In this invention, the term "hydroxyl group" usually refers to an -OH group, but it also includes salts of -OH groups and groups containing an -OH group. Examples of groups containing an -OH group include -OH groups bonded to heteroatoms, specifically Si-OH groups (silanol groups). Furthermore, a hydroxyl group precursor refers to a group that can generate a hydroxyl group or convert to a hydroxyl group, such as a group that generates a hydroxyl group through hydrolysis reactions, for example, an alkoxy group, an aryloxy group, a (mono, di, or tri)alkoxysilyl group, or a (mono, di, or tri)aryloxysilyl group.

[0027] As for the hydroxyl group and hydroxyl group precursor of the crosslinkable polymer, a hydroxyl group precursor is preferred, an alkoxysilyl group is more preferred, and a trialkoxysilyl group is even more preferred. The number of types of hydroxyl groups and hydroxyl group precursors present in a crosslinkable polymer is not particularly limited and may be one type or two or more types. In the present invention, depending on the properties to be expressed in the crosslinkable resin composition or resin molded article of the present invention, one type of crosslinkable polymer having one type of hydroxyl group or hydroxyl group precursor may be used, one type of crosslinkable polymer having multiple types of hydroxyl groups and / or hydroxyl group precursors may be used, furthermore, multiple types of crosslinkable polymers having one type of hydroxyl group or hydroxyl group precursor may be used (the type of hydroxyl group or hydroxyl group precursor may be the same or different for each crosslinkable polymer), or multiple types of crosslinkable polymers having multiple types of hydroxyl groups and / or hydroxyl group precursors may be used. The number of hydroxyl groups and hydroxyl group precursors present in a crosslinkable polymer is not particularly limited and is appropriately determined depending on the content of boron compounds, etc. For example, the number of hydroxyl groups and hydroxyl group precursors can be 2 to 300 on average per molecule of crosslinkable polymer, preferably 2 to 20. The number of hydroxyl groups and hydroxyl group precursors present in a crosslinkable polymer can be calculated, for example, from the molecular weight of the crosslinkable polymer.

[0028] The crosslinkable polymer may be an elastomer (including rubber), but from the viewpoint of the properties of the crosslinked resin composition, such as mechanical properties, it is preferable that it be a resin.

[0029] <Hydroxypolymer> Examples of hydroxypolymers are not particularly limited, but include polyvinyl alcohol (PVA), saponified ethylene vinyl acetate copolymers, ethylene-vinyl alcohol copolymers, polyglycerol methacrylate, and polymers having a diethanolamine skeleton. Commercially available crosslinkable polymers can also be used. For example, commercially available saponified ethylene vinyl acetate copolymers include Mersen® H-6051K, Mersen® H-6410M, Mersen® H-3051R, Mersen® H-6820, and Mersen® H-6822X (all trade names, manufactured by Tosoh Corporation). Commercially available ethylene vinyl alcohol copolymers include EVAL G156B and EVAL L171B (both trade names, manufactured by Kuraray Corporation).

[0030] <Modified polymer> Modified polymers only need to have at least one of a hydroxyl group and a hydroxyl group precursor as a substituent or modifying group. Examples include polymers containing components derived from monomers having a hydroxyl group or a hydroxyl group precursor, and polymers in which a compound having a hydroxyl group or a hydroxyl group precursor is substituted in the main chain. The polymers that form the modified polymer (polymers before the introduction of hydroxyl groups and hydroxyl group precursors) are not particularly limited, and include polymers having sites in the main chain or at their ends that can react with compounds having hydroxyl groups or hydroxyl group precursors, preferably polymers having sites in the main chain or at their ends that can react with grafting sites of a silane coupling agent in the presence of an organic peroxide. Examples of sites that can react with grafting include unsaturated bond sites in carbon chains and carbon atoms having hydrogen atoms. Examples of such polymers include thermoplastic elastomers, ethylene copolymer resins, modified polyethylene resins, polyolefin resins, polyester resins, and various rubbers. In addition to these, chlorine-containing resins (resins specified in JIS K 7229-1995) or fluorine-containing resins such as fluororubber can also be used.

[0031] Thermoplastic elastomers are not particularly limited, but examples include polyester elastomers, styrene elastomers, polyurethane elastomers, olefin elastomers, and polyamide elastomers.

[0032] The ethylene copolymer resin is not particularly limited, but examples include ethylene-α-olefin copolymers and polyolefin copolymers having an acid copolymer component or an acid ester copolymer component. Specifically, examples include ethylene-vinyl acetate copolymers (non-saponified), ethylene-(meth)acrylic acid copolymers, and ethylene-(meth)acrylate alkyl copolymers. The modified polyethylene resin can be, for example, any resin that has been modified from the above-mentioned ethylene copolymer. Examples include ethylene-vinyl acetate copolymer resin modified with polyorganosiloxane, polyolefin resin modified with unsaturated carboxylic acid, ethylene-vinyl acetate copolymer resin modified with unsaturated carboxylic acid, and ethylene-(meth)acrylic acid ester copolymer resin modified with unsaturated carboxylic acid.

[0033] The polyolefin resin is not particularly limited as long as it is a polymer obtained by polymerizing or copolymerizing a compound having ethylenically unsaturated bonds, other than the ethylene copolymer resin and other than the modified polyethylene resin, and any polymer resin conventionally used in resin compositions can be used. Examples include polyethylene and polypropylene resins, with polyethylene being particularly preferred. The polyethylene is not particularly limited, and examples include high-density polyethylene, low-density polyethylene, ultra-high molecular weight polyethylene, linear low-density polyethylene, and ultra-low-density polyethylene. Among these, linear low-density polyethylene and low-density polyethylene are preferred. The polypropylene is not particularly limited, and examples include propylene homopolymers, random polypropylene, and block polypropylene.

[0034] The polyester resin is not particularly limited, but examples include polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyethylene naphthalate (PEN), and polytrimethylene terephthalate (PTT).

[0035] The rubber used is not particularly limited, but examples include ethylene rubber, acrylic rubber, nitrile rubber, and styrene rubber. Specifically, examples of ethylene rubber include ethylene-propylene rubber, ethylene-butene rubber, ethylene-octene rubber, ethylene-propylene-diene rubber, and ethylene-butene-diene rubber.

[0036] (Silane graft polymer) As the crosslinkable polymer, a modified polymer is preferred, and a polymer that has undergone a grafting reaction with a silane coupling agent (silane graft polymer), as described later, is preferred. As for the silane graft polymer, it has a structure derived from the silane coupling agent, and as a polymer having the above-mentioned graft-reactive sites, a silane graft polyolefin resin obtained by grafting a silane coupling agent onto a polyolefin resin is preferred, and a silane graft polyethylene resin obtained by grafting a silane coupling agent onto a polyethylene resin is more preferred. Silane graft polymers can typically be synthesized by grafting a silane coupling agent onto a polymer that has graft-reactive sites, using a thermal radical initiator (organic peroxide).

[0037] - Silane coupling agent - Silane coupling agents have graft-reactive sites (or functional groups such as ethylenically unsaturated groups) that react with grafts in the presence of radicals generated by the decomposition of organic peroxides. Furthermore, silane coupling agents have reaction sites capable of silanol condensation (including sites produced by hydrolysis, such as silyl ester groups). Examples of such silane coupling agents include those conventionally used in silane crosslinking methods, and silane coupling agents having an ethylenically unsaturated group and a hydrolyzable silyl group are preferred. Examples of hydrolyzable silyl groups include the alkoxysilyl group and aryloxysilyl group described above in the section on hydroxyl group precursors, and (di or tri)alkoxysilyl groups are preferred. Specific examples of silane coupling agents include vinylsilanes such as vinyltrimethoxysilane (VTMS), vinyltriethoxysilane (VTES), vinyltributoxysilane, vinyldimethoxyethoxysilane, vinyldimethoxybutoxysilane, vinyldiethoxybutoxysilane, allyltrimethoxysilane, allyltriethoxysilane, and vinyltriacetoxysilane, and (meth)acryloxysilanes such as methacryloxypropyltrimethoxysilane, methacryloxypropyltriethoxysilane, and methacryloxypropylmethyldimethoxysilane. Silane coupling agents may be used individually or in combination of two or more types. They may also be used as is or diluted with a solvent.

[0038] - Organic peroxide - Organic peroxides generate radicals, at least by thermal decomposition, and act as catalysts to induce grafting reactions of silane coupling agents to polymers via radical reactions (covalent bond formation reactions between grafting sites of the silane coupling agent and graftable sites of the polymer). In particular, if the reaction site of the silane coupling agent contains, for example, an ethylenically unsaturated group, they act to induce grafting reactions via radical reactions between the ethylenically unsaturated group and the polymer (including the abstraction of hydrogen radicals from the polymer). There are no particular restrictions on the organic peroxide; for example, the general formula is R 1 -OO-R 2 , R 3 -OO-C(=O)R 4 , R 5 C(=O)-OO(C=O)R 6 A compound represented by is preferred. Here, R 1 ~R6 each independently represents an alkyl group, an aryl group or an acyl group. In R of each compound 1 to R 6 , it is preferable that all of them are alkyl groups, or one of them is an alkyl group and the remainder are acyl groups. Examples of such organic peroxides include dicumyl peroxide (DCP), di-tert-butyl peroxide, 2,5-dimethyl-2,5-di-(tert-butylperoxy)hexane, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexyne-3, 1,3-bis(tert-butylperoxyisopropyl)benzene, 1,1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane, n-butyl-4,4-bis(tert-butylperoxy)valerate, benzoyl peroxide, p-chlorobenzoyl peroxide, 2,4-dichlorobenzoyl peroxide, tert-butyl peroxybenzoate, tert-butyl peroxyisopropyl carbonate, diacetyl peroxide, lauroyl peroxide, and tert-butyl cumyl peroxide. Among these, dicumyl peroxide, 2,5-dimethyl-2,5-di-(tert-butylperoxy)hexane, and 2,5-dimethyl-2,5-di(tert-butylperoxy)hexyne-3 are preferable from the viewpoints of odor, coloration, and scorch stability. The decomposition temperature (exothermic onset temperature) of the organic peroxide under a normal pressure (about 0.1 MPa) environment is preferably 80 to 195°C, and particularly preferably 125 to 180°C. In the present invention, the decomposition temperature of an organic peroxide means the temperature at which when a single-composition organic peroxide is heated, it itself undergoes a decomposition reaction into two or more compounds at a certain fixed temperature or temperature range. Specifically, it refers to the temperature at which endotherm or exotherm starts when heated from room temperature at a temperature increase rate of 5°C / min in a nitrogen gas atmosphere by thermal analysis such as DSC method.

[0039] In the grafting reaction of a silane coupling agent in the presence of an organic peroxide (hereinafter sometimes simply referred to as the grafting reaction), the amount of silane coupling agent used is not particularly limited, but is preferably an amount equal to the amount of hydroxyl groups present in the crosslinkable polymer. Specifically, in order to impart excellent properties to the crosslinked resin composition of the present invention, the amount is more preferably 1 to 40 parts by mass, even more preferably 2 to 30 parts by mass, particularly preferably 2 to 25 parts by mass, and most preferably 2 to 5 parts by mass, per 100 parts by mass of the polymer to be grafted. In the grafting reaction, the amount of organic peroxide used is not particularly limited, but for example, in order to efficiently cause and proceed the grafting reaction of the silane coupling agent, it is preferably 0.01 to 1.0 parts by mass, more preferably 0.05 to 0.8 parts by mass, and even more preferably 0.1 to 0.6 parts by mass per 100 parts by mass of the polymer to be grafted.

[0040] The reaction conditions for the grafting reaction are not particularly limited, and conventional reaction conditions for grafting reactions can be applied. Typically, melting and kneading conditions at a temperature above the decomposition temperature of the organic peroxide are used. Specifically, the heating temperature is preferably 140 to 230°C, but can also be 175 to 210°C.

[0041] The silane graft polymer obtained as described above can also be a commercially available product such as Linkron (trade name, manufactured by Mitsubishi Chemical Corporation).

[0042] <Other polymers> Other polymers that may be included in the base resin are not particularly limited, as long as they are polymers that do not correspond to crosslinkable polymers, and polymers that do not have hydroxyl groups and hydroxyl group precursors (non-crosslinkable polymers). Examples of non-crosslinkable polymers include the various polymers mentioned above that form modified polymers, and among these, ethylene copolymer resins and polyolefin resins are preferred.

[0043] (Composition of the base resin) In the present invention, the content of the crosslinkable polymer in the base resin is not particularly limited, but can be 70% by mass or more, preferably 80% by mass or more, and more preferably 90% by mass or more, in terms of the crosslinking reaction of the crosslinkable resin composition of the present invention and the properties of the crosslinkable resin composition of the present invention. On the other hand, the upper limit of the crosslinkable polymer content is preferably 100% by mass, but can also be 95% by mass or less, or 90% by mass or less. In the present invention, when synthesizing a crosslinkable polymer, the mass of the crosslinkable polymer is, for convenience, the total mass of each component (raw material) that forms the crosslinkable polymer. For example, when synthesizing a silane graft polymer as a crosslinkable polymer, the mass of the silane graft polymer is the total mass of the polymer to be grafted and the silane coupling agent (before the grafting reaction, i.e., the amount used), regardless of the grafting rate of the silane coupling agent.

[0044] When the crosslinkable resin composition of the present invention contains two or more crosslinkable polymers, the content of each crosslinkable polymer is not particularly limited and can be determined as appropriate. For example, when a hydroxy polymer and a modified polymer are used in combination, it is preferable that the content of the modified polymer is greater than the content of the hydroxy polymer, and the mass ratio of the content of the modified polymer to the content of the hydroxy polymer [content of modified polymer / content of hydroxy polymer] can be 2 to 35, and is preferably 2 to 15.

[0045] The content of other polymers in the base resin is not particularly limited, but is preferably 0 to 30% by mass, and can also be 10 to 20% by mass, in terms of the crosslinking reaction of the crosslinkable resin composition of the present invention and the properties of the crosslinkable resin composition of the present invention.

[0046] [Boron compounds] The boron compound used in the present invention may be any compound containing a boron atom, and it is preferable that it has a BO bond (-BO-) in that it allows the crosslinking reaction to occur rapidly. Furthermore, the boron compound is preferably a boron compound (also called a reactive boron compound) that has a reactive group that reacts with a hydroxyl group or hydroxyl group precursor of the crosslinkable polymer, in that it allows the crosslinking reaction to be completed rapidly. The reactive group is not particularly limited, but can be appropriately selected depending on the reaction mechanism with the hydroxyl group or hydroxyl group precursor. For example, a hydroxyl group that undergoes a dehydration condensation reaction with a hydroxyl group, an alkoxy group or aryloxy group that undergoes a transesterification reaction (including a dehydration condensation reaction after hydrolysis) with a hydroxyl group, or a group described above as a hydroxyl group precursor of the crosslinkable polymer (excluding hydroxyl groups, alkoxy groups and aryloxy groups), and further, a structure that gives a BOH group after hydrolysis, such as the 4,4,5,5-tetramethyl-1,3,2-dioxaborolane structure (for example, a cyclic boronic acid ester in which a boronic acid is protected with a diol). The reactive group is preferably a hydroxyl group because it allows the crosslinking reaction to be completed quickly. The hydroxyl group may also form a salt. The number of types of reactive groups that a single molecule of boron compound may have is not particularly limited. The number of reactive groups that a single molecule of boron compound may have is not particularly limited, and may be one or more, but it is preferable to have two or more, and more preferably two to four, in order to contribute to the formation of the crosslinking structure.

[0047] As described above, when a boron compound is incorporated into a crosslinked structure to form a crosslinked structure, the boron compound can also be called a crosslinking agent. The boron compounds used in the present invention, particularly boron compounds as crosslinking agents (reactive boron compounds), differ from boron compounds as inorganic fillers such as aluminum borate, boron nitride, and zinc borate, as shown in the above example of the estimated structure of the crosslinked structure, in that they have one or more, preferably two or more, reactive groups. In this respect, the boron compounds used in the present invention can be said to be compounds other than boron compounds as inorganic fillers, for example, compounds other than aluminum borate, compounds other than boron nitride, and compounds other than zinc borate.

[0048] The boron compound is not particularly limited as long as it contributes to the occurrence and promotion of the crosslinking reaction, but compounds having the above-mentioned bond or reactive group are preferred, and although it may be a high molecular weight compound (polymer), it is preferable that it be a low molecular weight compound (non-polymerizable compound). Examples of boron compounds include boric acid, borate, boronic acid, boric acid ester, and boronic acid ester. These compounds may be anhydrous or hydrated. Boric acid includes orthoboric acid, tetraboric acid, etc., and orthoboric acid is preferred because it can complete the crosslinking reaction quickly. Examples of borate salts include Na2B4O5(OH)4·8H2O, Na2B4O7, K2B4O7·4H2O, etc. Examples of boronic acids include alkylboronic acids such as methylboronic acid, phenylboronic acid, and arylboronic acids such as 1,4-phenylenediboronic acid, and 1,4-phenylenediboronic acid is preferred because it can complete the crosslinking reaction quickly. Examples of boric acid esters and boronic acid esters include alkyl esters or aryl esters, respectively. Among the compounds mentioned above, the boron compound is preferably boric acid, borate, or boronic acid, more preferably boric acid or boronic acid, and even more preferably boric acid, as these compounds allow for rapid completion of the crosslinking reaction.

[0049] [Inorganic filler] The crosslinkable resin composition of the present invention may contain an inorganic filler. The inorganic fillers are not particularly limited and include metal hydrates 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, talc, and other compounds having hydroxyl groups or water of crystallization. Other examples include boron nitride, silica (crystalline silica, amorphous silica, etc.), carbon black, clay (calcined clay), zinc oxide, tin oxide, titanium oxide, molybdenum oxide, antimony trioxide, silicone compounds, quartz, zinc borate, white carbon, zinc borate, zinc hydroxystannate, and zinc stannate. The inorganic filler may be surface-treated. For example, a surface-treated inorganic filler, such as one treated with a silane coupling agent, can be used. Examples of silane coupling agent surface-treated inorganic fillers include Kisma 5L and Kisma 5P (both trade names, made from magnesium hydroxide, manufactured by Kyowa Chemical Industry Co., Ltd., etc.). As the inorganic filler, at least one selected from the group consisting of silica, aluminum hydroxide, magnesium hydroxide, and calcium carbonate is preferred. One type of inorganic filler may be used alone, or two or more types may be used in combination.

[0050] [Plasticizer components] The crosslinkable resin composition of the present invention may contain at least one of a plasticizer and an oil as a plasticizer component. The oil is not particularly limited, but examples include organic oils and mineral oils. Examples include soybean oil, paraffin oil, naphthenic oil, and aromatic oil. Among these, soybean oil, paraffin oil, and naphthenic oil are preferred. Examples of plasticizers include various types commonly used in polyvinyl chloride. Examples include trialkyl trimellitic acid (C8, C10), pyromellitic acid ester plasticizers, phthalate ester plasticizers, adipic acid ester plasticizers, and polyester plasticizers.

[0051] [Silanol condensation catalyst] The crosslinkable resin composition of the present invention may contain a silanol condensation catalyst to promote the dehydration condensation of the silanol condensation-capable reaction sites of the silane coupling agent, particularly between hydrolyzable silyl groups. The silanol condensation catalyst has the function of causing a condensation reaction of the silane coupling agent grafted onto the crosslinkable polymer in the presence of moisture. The silanol condensation catalyst used in the present invention is not particularly limited, and examples include organotin compounds, metal soaps, platinum compounds, etc. Common silanol condensation catalysts include, for example, dibutyltin dilaurate, dioctyltin dilaurate, dibutyltin dioctiate, dibutyltin diacetate, zinc stearate, lead stearate, barium stearate, calcium stearate, sodium stearate, lead naphthenate, lead sulfate, zinc sulfate, and organoplatin compounds. From the viewpoint of promoting the silanol condensation reaction, an organotin compound is preferred as the silanol condensation catalyst, and dibutyltin dilaurate, dioctyltin dilaurate, dibutyltin dioctiate, and dibutyltin diacetate are more preferred. On the other hand, from the viewpoint of avoiding environmental and human health impacts, compounds other than organotin compounds are preferred. The silanol condensation catalyst may be mixed with a resin for use as desired. Such resins (also called carrier resins) are not particularly limited, but any of the resins or rubbers described in the base resin section can be used.

[0052] [Additives] The crosslinkable resin composition of the present invention may contain various commonly used additives to the extent that they do not impair the effects of the present invention. Examples of such additives include crosslinking aids, antioxidants, lubricants, metal deactivators, flame retardants, and flame retardant aids.

[0053] <Crosslinking agent> A crosslinking aid is a substance that forms a partially crosslinked structure with a crosslinked polymer in the presence of an organic peroxide. Examples include (meth)acrylate compounds such as polypropylene glycol diacrylate and trimethylolpropane triacrylate, allyl compounds such as triallyl cyanurate, maleimide compounds, and divinyl compounds. It is preferable that the crosslinked structure formed by the crosslinking aid is formed separately from the crosslinked structure formed by the hydroxyl group or hydroxyl group precursor of the crosslinkable polymer.

[0054] <Antioxidant> The antioxidants are not particularly limited, but examples include amine antioxidants, phenol antioxidants, or sulfur antioxidants. Examples of amine antioxidants include 4,4'-dioctyldiphenylamine, N,N'-diphenyl-p-phenylenediamine, and polymers of 2,2,4-trimethyl-1,2-dihydroquinoline. Examples of phenol antioxidants include pentaerythrityl-tetrakis(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate), octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, and 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene. Examples of sulfur antioxidants include bis(2-methyl-4-(3-n-alkylthiopropionyloxy)-5-tert-butylphenyl) sulfide, 2-mercaptobenzimidazole and its zinc salt, and pentaerythritol-tetrakis(3-lauryl-thiopropionate).

[0055] <Lubricant> Lubricants are not particularly limited, but examples include hydrocarbon-based, siloxane-based, fatty acid-based, fatty acid amide-based, ester-based, alcohol-based, and metal soap-based lubricants.

[0056] <Metal deactivators> Examples of metal deactivators include N,N'-bis(3-(3,5-di-t-butyl-4-hydroxyphenyl)propionyl)hydrazine, 3-(N-salicyroyl)amino-1,2,4-triazole, and 2,2'-oxamide bis(ethyl 3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate).

[0057] <Flame retardants, flame retardant enhancers> Examples of flame retardants and flame retardant additives include carbon black, clay, zinc oxide, tin oxide, titanium oxide, magnesium oxide, molybdenum oxide, antimony trioxide, silicone compounds, quartz, talc, calcium carbonate, magnesium carbonate, zinc borate, and white carbon.

[0058] [Composition of crosslinkable resin composition] The content of the boron compound in the crosslinkable resin composition is appropriately determined considering the content of the boron atoms as described above. The content of the boron compound is preferably 0.10 to 20.0 parts by mass, more preferably 0.40 to 10.0 parts by mass, and even more preferably 0.90 to 3.0 parts by mass, per 100 parts by mass of the base resin, in order to complete the crosslinking reaction quickly.

[0059] The amount of inorganic filler in the crosslinkable resin composition is not particularly limited, but for example, in terms of heat resistance and mechanical properties, it is preferably 10 to 400 parts by mass, more preferably 10 to 300 parts by mass, and even more preferably 10 to 200 parts by mass per 100 parts by mass of the base resin.

[0060] The total content of plasticizer components in the crosslinkable resin composition is not particularly limited, but is preferably 0 to 80 parts by mass, more preferably 0 to 60 parts by mass, and even more preferably 0 to 30 parts by mass, per 100 parts by mass of the base resin.

[0061] In the crosslinkable resin composition, the content of the silanol condensation catalyst is preferably 0 to 0.5 parts by mass, and more preferably 0 to 0.3 parts by mass, per 100 parts by mass of the base resin, in order to construct a crosslinked structure through the condensation reaction of silane coupling agents.

[0062] The content of the crosslinking aid in the crosslinkable resin composition is not particularly limited, but for example, it is preferably 0.01 to 50 parts by mass, more preferably 0.1 to 30 parts by mass, and even more preferably 0.1 to 15 parts by mass per 100 parts by mass of the base resin. The content of antioxidants in the crosslinkable resin composition is not particularly limited, but is preferably 0.1 to 15.0 parts by mass, and more preferably 0.1 to 10 parts by mass, per 100 parts by mass of the base resin. The lubricant content in the crosslinkable resin composition is not particularly limited, but is preferably 0.01 to 20 parts by mass, more preferably 0.1 to 15 parts by mass, and even more preferably 0.1 to 10 parts by mass, per 100 parts by mass of the base resin. The content of the metal deactivator in the crosslinkable resin composition is not particularly limited, but is preferably 0.01 to 20 parts by mass, more preferably 0.1 to 10 parts by mass, and even more preferably 0.1 to 5 parts by mass, per 100 parts by mass of the base resin. The total content of flame retardants and flame retardant aids in the crosslinkable resin composition is not particularly limited, but is preferably 10 to 400 parts by mass, more preferably 10 to 300 parts by mass, and even more preferably 10 to 200 parts by mass, per 100 parts by mass of the base resin.

[0063] [Composition of crosslinked resin composition and resin molded article] Since the crosslinked resin composition and resin molded articles of the present invention are formed by crosslinking the crosslinkable resin composition of the present invention, the types and content of each component in the crosslinked resin composition and resin molded articles are, in fact, the same as the types and content of each component in the crosslinkable resin composition of the present invention. The content of boron atoms in the crosslinked resin composition and resin molded articles is also the same. However, the silanol condensation catalyst usually decomposes and disappears. In addition, the boron compound may be incorporated into the crosslinked structure, in which case the content of the boron compound in the crosslinked resin composition and the resin molded article is less than the content of the boron compound in the crosslinkable resin composition, and cannot be uniquely determined by variations in the number of hydroxyl groups, etc., of the crosslinkable polymer, the content of the boron compound in the crosslinkable resin composition, etc. If the boron compound is contained in excess relative to the number of hydroxyl groups, etc., of the crosslinkable polymer in the crosslinkable resin composition, the boron compound may remain in the crosslinked resin composition and the resin molded article as unreacted or undecomposed material. Note that the base resin content is calculated based on the content before crosslinking.

[0064] [[Method for producing a crosslinked resin composition]] The crosslinked resin composition of the present invention is not particularly limited, but can be prepared, for example, by blending each component in a blender in a mixing ratio that satisfies the composition of the above-mentioned crosslinkable resin composition, and then melt-kneading it in a commonly used kneading device such as a single-screw extruder, twin-screw extruder, Banbury mixer, kneader, or roll. The melt-kneading temperature is not particularly limited, but 150 to 240°C is preferred. The melt-kneading time can be the minimum time necessary to prepare each of the above components into a homogeneous composition, for example, several minutes to several hours. The order in which the components are mixed is not particularly limited. The crosslinked resin composition of the present invention can also be appropriately pelletized and prepared as pellets.

[0065] When using a silane graft polymer as the crosslinkable polymer, the following methods 1 to 4 are listed as specific methods for producing the crosslinkable resin composition, but the method is not limited to these and can be modified as appropriate. Manufacturing method 1: First, the components for preparing the silane graft polymer are melted and kneaded together to form the silane graft polymer Prepare the rimer (prepare the base resin), and then (continuously) add boric acid compounds, etc. The crosslinkable resin composition of the present invention is produced by adding the material, melting and kneading it, and then pelletizing it as appropriate. How to Method 2: Melt and knead the components to prepare the silane graft polymer. Prepare (prepare a crosslinkable polymer), and pelletize it as appropriate to make compound A. Prepare the following: Separately, melt-knead a non-crosslinkable polymer and a boron compound, and adjust as needed. Next, pelletize it as desired to prepare compound B. Then, combine compound A and... A method for producing the crosslinkable resin composition of the present invention by melting and kneading compound B. Manufacturing method 3: Melt and knead the components to prepare the silane graft polymer. Prepare (prepare a crosslinkable polymer), and pelletize it as appropriate to make compound A. Prepare the mixture. After dry blending Compound A and the boron compound (extruder) The crosslinkable resin composition of the present invention is produced by melt-kneading (in an extruder) using the methods described above. method The conditions for dry blending are not particularly limited as long as it is a dry mixing process, but for example, 10 Mix at ~60°C (preferably near room temperature (20~25°C)) for several minutes to several hours. The conditions are listed. Manufacturing method 4: Melt and knead the components to prepare the silane graft polymer. Prepare (prepare a crosslinkable polymer), and pelletize it as appropriate to make compound A. Prepare. Put compound A into a twin-screw extruder, for example, and in the twin-screw extruder... The crosslinkable resin composition of the present invention is produced by melt-kneading with elementary compounds (in a twin-screw extruder). How to

[0066] [[Method for producing crosslinked resin composition]] Since the crosslinking reaction of the crosslinkable resin composition of the present invention proceeds rapidly, the crosslinking reaction may be completed while the crosslinkable polymer and the boron compound are melt-kneaded in the method for producing the crosslinkable resin composition of the present invention. In this case, the crosslinkable resin composition of the present invention can be produced during or after the melt-kneading. Even if the crosslinking reaction is not completed while the crosslinkable polymer and the boron compound are melt-kneaded, the crosslinking reaction will proceed rapidly thereafter, and the crosslinking reaction may be completed within 6 hours (preferably within 1 hour, or even earlier in the preferred embodiment, until the material is wound) after the completion of melt-kneading, thereby producing the crosslinkable resin composition of the present invention.

[0067] [[Manufacturing method for resin molded products]] The resin molded articles of the present invention can be manufactured by molding the crosslinked resin composition of the present invention into a predetermined shape and dimensions. The crosslinked resin composition of the present invention has the characteristic that it maintains moldability even after crosslinking, and can be molded even after crosslinking. When the crosslinkable resin composition of the present invention or the crosslinkable resin composition is melt-kneaded in an extruder or the like, a resin molded article can be obtained simultaneously with or after the production of the crosslinkable resin composition of the present invention or the crosslinkable resin composition. The molding method is not particularly limited and includes, for example, press molding, extrusion molding using an extruder, extrusion molding using an injection molding machine, and molding using other molding machines. The molding temperature should be above the melting temperature of the crosslinked resin composition, and can be, for example, 100 to 240°C, and preferably 140 to 240°C. [Examples]

[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] Details of each compound used in the examples and comparative examples are shown in Table 1 and below. <Base resin> PE: Polyethylene (UBEC180 (product name), manufactured by Ube Maruzen Polyethylene Co., Ltd.) EVA saponified product: Saponified product of ethylene vinyl acetate copolymer (Mersen® H-6051K (product name), manufactured by Tosoh Corporation) <Organic peroxide> 2,5-Dimethyl-2,5-di(tert-butylperoxy)hexane (Perhexa 25B (trade name), manufactured by NOF Corporation) <Silane coupling agent> VTMS: Vinyltrimethoxysilane (KBM-1003 (product name), manufactured by Shin-Etsu Chemical Co., Ltd.) VTES: Vinyltriethoxysilane (KBE-1003 (product name), manufactured by Shin-Etsu Chemical Co., Ltd.) <Boron compounds> Boric acid: Orthoboric acid (manufactured by Ken-ei Pharmaceutical Co., Ltd.) Boronic acid: 1,4-phenylenediboronic acid (manufactured by Tokyo Chemical Industry Co., Ltd.) <Silanol condensation catalyst> OT-1: Dioctyl tin dilaurate (ADEKA stub OT-1 (product name), manufactured by ADEKA Corporation)

[0070] [[Example A and Comparative Example C: Progress Test of Crosslinking Reaction]] To 180 g of polyethylene being kneaded in a laboplast mill at 150°C, a mixture of 4.0 g of VTMS and 0.2 g of 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane was added and kneaded at 60 rpm for 30 minutes (silane graft polymer was prepared). Subsequently, 1.8 g of boric acid (Example A) or 0.2 g of dioctyl tin dilaurate (Comparative Example C) was added to the kneaded mixture and kneaded at 60 rpm for 10 minutes. In this way, crosslinkable resin composition A of Example A and crosslinkable resin composition C of Comparative Example C were prepared. The boron atom content in crosslinkable resin composition A was 0.171 parts by mass per 100 parts by mass of the base resin (silane graft polymer). Immediately after preparation (within 1 hour of melt mixing completion), each composition was rolled to a thickness of 1 mm, and then pressed at 140°C for 10 minutes (press pressure 15.8 MPa) to produce sheet samples A1 and C1, and the gel fraction was measured. In addition, the gel fraction of sheet samples A2 and C2 was measured after each sheet sample was left to stand for 7 days under moist heat conditions of 60°C and 95% relative humidity in an air atmosphere. The gel fraction is a parameter indicating the degree of crosslinking and was measured by the xylene method according to JIS C 3005.

[0071] As a result, sheet samples prepared using crosslinkable resin composition A containing boric acid showed a gel fraction of 70% (saturation value) both immediately after mixing (A1) and after standing for 7 days (A2). Furthermore, when sheet sample A3, which was prepared by standing sheet sample A1 for 7 days under atmospheric conditions of 25°C and 50% relative humidity, was measured for gel fraction, it was also 70% (saturation value). On the other hand, sheet samples prepared using crosslinkable resin composition C containing dioctyl tin dilaurate showed a gel fraction of 48% immediately after mixing (sheet sample C1) and a gel fraction of 70% (saturation value) after standing for 7 days (sheet sample C2). These results confirmed that using dioctyl tin dilaurate resulted in a longer crosslinking reaction time, while using boric acid resulted in a rapid completion of the crosslinking reaction. Furthermore, the fact that the kneading torque of the laboplastmill increased immediately after adding boric acid during the melt mixing of crosslinkable resin composition A also supported the fact that the crosslinking reaction was proceeding rapidly. Furthermore, when the progress of the cross-linking reaction was tested in the same manner as in Example A, except that boronic acid was used instead of boric acid, the same results as in Example A were obtained.

[0072] [[Examples 1-9 and Comparative Examples 1-3]] In Examples 1-9 and Comparative Examples 1-3, each composition prepared as described below was rolled to a thickness of 1 mm, then pressed at 140°C for 10 minutes (press pressure 15.8 MPa) to produce sheet samples, which were then left to stand for 7 days in an atmosphere at 25°C and 50% relative humidity. In Examples 1 to 9, it was confirmed that the kneading torque of the Laboplastmill increased sufficiently (indicating that the crosslinking reaction had progressed) 10 minutes after adding the boron-based compound to the base resin (crosslinkable polymer) during melt kneading (10 minutes of kneading time after addition).

[0073] Sheet samples left in the atmosphere for 7 days were subjected to gel fraction measurement and tensile testing. The gel fraction is a value measured by the xylene method in accordance with JIS C 3005, and in this example and comparative example, it is desirable to have a gel fraction of 50% or more. Tensile tests were conducted according to JIS K 7161, under conditions of a gauge length of 20 mm and a tensile speed of 200 mm / min, measuring 100% Modulus (MPa) and tensile elongation (%). This test is for reference purposes only; in this test, a 100% Modulus of 11.0 MPa or higher is desirable, and a tensile elongation of 150% or higher is desirable. Table 1 shows the values ​​obtained from the blending amounts during the preparation of the crosslinkable resin composition for each example and comparative example, as the content of boron atoms in 100 parts by mass of the base resin (100 parts by mass of the crosslinkable polymer and silane coupling agent combined).

[0074] [Example 1] To 180 g of polyethylene (PE) being kneaded at 150°C, a mixture of 4.0 g of VTMS and 0.2 g of 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane was added and kneaded at 60 rpm for 30 minutes. Then, 0.2 g of boric acid was added and kneaded at 60 rpm for 10 minutes. In this way, crosslinkable resin composition 1 was prepared. Table 1 shows the gel fraction, 100% Modulus, and tensile elongation measurements of sheet samples prepared using this crosslinkable resin composition 1.

[0075] [Example 2] To 180 g of polyethylene being kneaded at 150°C, a mixture of 4.0 g of VTMS and 0.2 g of 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane was added and kneaded at 60 rpm for 30 minutes. Then, 0.9 g of boric acid was added and kneaded at 60 rpm for 10 minutes. In this way, crosslinkable resin composition 2 was prepared. Table 1 shows the gel fraction, 100% Modulus, and tensile elongation measurements of sheet samples prepared using this crosslinkable resin composition 2.

[0076] [Example 3] To 180 g of polyethylene being kneaded at 150°C, a mixture of 4.0 g of VTMS and 0.2 g of 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane was added and kneaded at 60 rpm for 30 minutes. Then, 1.8 g of boric acid was added and kneaded at 60 rpm for 10 minutes. In this way, crosslinkable resin composition 3 was prepared. Table 1 shows the gel fraction, 100% Modulus, and tensile elongation measurements of sheet samples prepared using this crosslinkable resin composition 3.

[0077] [Example 4] To 180 g of polyethylene being kneaded at 150°C, a mixture of 4.0 g of VTMS and 0.2 g of 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane was added and kneaded at 60 rpm for 30 minutes. Then, 5.2 g of boric acid was added and kneaded at 60 rpm for 10 minutes. In this way, crosslinkable resin composition 4 was prepared. Table 1 shows the gel fraction, 100% Modulus, and tensile elongation measurements of sheet samples prepared using this crosslinkable resin composition 4.

[0078] [Example 5] To 180 g of polyethylene being kneaded at 150°C, a mixture of 4.0 g of VTMS and 0.2 g of 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane was added and kneaded at 60 rpm for 30 minutes. Then, 18.0 g of boric acid was added and kneaded at 60 rpm for 10 minutes. In this way, crosslinkable resin composition 5 was prepared. Table 1 shows the measured gel fraction, 100% Modulus, and tensile elongation of sheet samples prepared using this crosslinkable resin composition 5.

[0079] [Example 6] To 180 g of polyethylene being kneaded at 150°C, a mixture of 4.0 g of VTMS and 0.2 g of 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane was added and kneaded at 60 rpm for 30 minutes. Then, 30.0 g of boric acid was added and kneaded at 60 rpm for 10 minutes. In this way, crosslinkable resin composition 6 was prepared. Table 1 shows the gel fraction, 100% Modulus, and tensile elongation measurements of sheet samples prepared using this crosslinkable resin composition 6.

[0080] [Example 7] To 180 g of polyethylene being kneaded at 150°C, a mixture of 5.1 g of VTES and 0.2 g of 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane was added and kneaded at 60 rpm for 30 minutes. Then, 1.8 g of boric acid was added and kneaded at 60 rpm for 10 minutes. In this way, crosslinkable resin composition 7 was prepared. Table 1 shows the gel fraction, 100% Modulus, and tensile elongation measurements of sheet samples prepared using this crosslinkable resin composition 7.

[0081] [Example 8] To 180 g of polyethylene being kneaded at 150°C, a mixture of 4.0 g of VTMS and 0.2 g of 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane was added and kneaded at 60 rpm for 30 minutes. Then, 1.8 g of boronic acid was added and kneaded at 60 rpm for 10 minutes. In this way, crosslinkable resin composition 8 was prepared. Table 1 shows the gel fraction, 100% Modulus, and tensile elongation measurements of sheet samples prepared using this crosslinkable resin composition 8.

[0082] [Example 9] To 160 g of polyethylene being kneaded at 150°C, a mixture of 3.5 g of VTMS and 0.2 g of 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane was added and kneaded at 60 rpm for 30 minutes. Then, 20.0 g of saponified ethylene vinyl acetate copolymer (EVA saponified) was added and kneaded at 60 rpm for 5 minutes, followed by the addition of 1.8 g of boric acid and kneaded at 60 rpm for 10 minutes. In this way, crosslinkable resin composition 9 was prepared. Table 1 shows the measured gel fraction, 100% Modulus, and tensile elongation of sheet samples prepared using this crosslinkable resin composition 9.

[0083] [Comparative Example 1] A mixture of 4.0 g of VTMS and 0.2 g of 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane was added to 180 g of polyethylene being kneaded at 150°C, and the mixture was kneaded at 60 rpm for 30 minutes. In this way, resin composition C1 was prepared. Table 1 shows the gel fraction, 100% Modulus, and tensile elongation measurements of sheet samples prepared using this resin composition C1.

[0084] [Comparative Example 2] To 180 g of polyethylene being kneaded at 150°C, a mixture of 4.0 g of VTMS and 0.2 g of 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane was added and kneaded at 60 rpm for 30 minutes. Then, 0.1 g of boric acid was added and kneaded at 60 rpm for 10 minutes. In this way, resin composition C2 was prepared. Table 1 shows the gel fraction, 100% Modulus, and tensile elongation measurements of sheet samples prepared using this resin composition C2.

[0085] [Comparative Example 3] To 180 g of polyethylene being kneaded at 150°C, a mixture of 5.1 g of VTES and 0.2 g of 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane was added and kneaded at 60 rpm for 30 minutes. Then, 0.2 g of dioctyl tin dilaurate (OT-1) was added as a silanol condensation catalyst (simply referred to as "condensation catalyst" in Table 1) and kneaded at 60 rpm for 10 minutes. In this way, resin composition C3 was prepared. Table 1 shows the measured gel fraction, 100% Modulus, and tensile elongation of sheet samples prepared using this resin composition C3.

[0086] [[Example 10]] A crosslinkable resin composition 10 was prepared by mixing an aqueous solution of polyvinyl alcohol with boric acid instead of polyethylene. It was confirmed that the crosslinking reaction proceeded rapidly even in a crosslinkable resin composition 10 containing polyvinyl alcohol alone as the base resin.

[0087] [Table 1]

[0088] The results shown in Table 1 reveal the following: In other words, in resin composition C1 (Comparative Example 1), which does not contain boron compounds or dioctyl tin dilaurate, the crosslinking reaction of the crosslinkable polymer did not proceed even after 7 days. On the other hand, in resin composition C2 (Comparative Example 2), which had too little boron content, the crosslinking reaction of the crosslinkable polymer occurred, but it did not proceed smoothly. This suggests that the boron compounds are not acting as catalysts to promote the crosslinking reaction like dioctyl tin dilaurate, but rather may be incorporated into the crosslinking structure.

[0089] In contrast, in the crosslinkable resin compositions 1 to 9 of Examples 1 to 9, which contained a boron compound in a predetermined proportion to form boron atoms, the torque increased 10 minutes after the addition of the boron compound, confirming that the crosslinking reaction of the crosslinkable polymer proceeded rapidly. Furthermore, it was confirmed that the 100% Modulus and tensile elongation of the sheet samples prepared with crosslinkable resin compositions 1 to 9 exhibited sufficient performance. Furthermore, although the crosslinkable resin composition 7 of Example 7 contains VTES, which is less reactive than VTMS, the crosslinking reaction proceeded rapidly due to the boron compound. This is evident from the increase in torque mentioned above and the comparison of gel fraction with Comparative Example 3. Therefore, in the present invention, when using a silane graft polymer, a silane coupling agent with lower crosslinking reactivity than VTMS can be used, and the constraints on silane coupling agents can be relaxed or eliminated. In particular, silane coupling agents with high crosslinking reactivity are highly volatile and pose a risk of deteriorating the working environment, but there is an advantage in being able to use a silane coupling agent that can improve the working environment and enhance safety in place of a silane coupling agent with high crosslinking reactivity.

[0090] From the above results, it can be seen that the present invention can rapidly complete the crosslinking reaction without requiring special crosslinking equipment such as an electron beam generator, and without using organotin compounds as silanol condensation catalysts, which are of concern due to their impact on the environment and human health. Since the crosslinking reaction proceeds rapidly from the preparation of the crosslinkable resin composition, the crosslinking reaction can be rapidly carried out and completed even if the object to be crosslinked is thick or large in size, thus alleviating or eliminating the limitations on the object to be crosslinked that were a problem in the past. Moreover, since the crosslinking reaction proceeds rapidly from the preparation of the crosslinkable resin composition, it is possible to alleviate or eliminate the limitations on the polymer used (regarding the glass transition temperature), as in the organic peroxide crosslinking method, and it can be seen that a wide variety of polymers can be used.

Claims

1. A crosslinked resin composition comprising a base resin containing a polymer having at least one of a hydroxyl group and a hydroxyl group precursor, a boron compound, wherein the content of boron atoms per 100 parts by mass of the base resin is 0.019 parts by mass or more, and the polymer has a structure derived from a silane coupling agent, A crosslinked resin composition having a gel fraction of 50% or more.

2. The crosslinked resin composition according to claim 1, wherein the boron compound comprises any of boric acid, boronic acid, and a borate.

3. The crosslinked resin composition according to claim 1, wherein the silane coupling agent has an alkoxysilyl group.

4. The crosslinked resin composition according to claim 1, having a B-O bond.

5. A crosslinked resin composition comprising a base resin containing a polymer other than polyvinyl alcohol having at least one of a hydroxyl group and a hydroxyl group precursor, and a boron compound, wherein the content of boron atoms per 100 parts by mass of the base resin is 0.019 parts by mass or more, A crosslinked resin composition having a gel fraction of 50% or more.

6. The crosslinked resin composition according to claim 5, wherein the boron compound comprises any of boric acid, boronic acid, and a borate.

7. The crosslinked resin composition according to claim 5, having a B-O bond.

8. A resin molded article comprising the crosslinked resin composition according to any one of claims 1 to 7.

9. A resin composition kit comprising a first agent containing a polymer having at least one of a hydroxyl group and a hydroxyl group precursor, wherein at least one of the polymers has a structure derived from a silane coupling agent, and a second agent containing a boron compound, A resin composition kit in which the first agent and the second agent are mixed and crosslinked in such a ratio that the content of boron atoms per 100 parts by mass of a base resin containing the polymer contained in the mixture of the first agent and the second agent is 0.019 parts by mass or more.

10. A resin composition kit comprising a first agent containing a polymer having at least one of a hydroxyl group and a hydroxyl group precursor, and a second agent containing a boron compound, The boron compound comprises any of boric acid, boronic acid, and borate, A resin composition kit in which the first agent and the second agent are mixed and crosslinked in such a ratio that the content of boron atoms per 100 parts by mass of a base resin containing the polymer contained in the mixture of the first agent and the second agent is 0.019 parts by mass or more.

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