Crosslinkable polymer composition, crosslinked polymer material, insulated wire, and wire harness

Abstract

Provided are: a crosslinkable polymer composition which can be crosslinked by heating and which can be converted from a state having low thermal deformability to a state having high thermal deformability at a certain temperature; and a crosslinked polymer material which is obtained by crosslinking such a crosslinkable polymer composition. And an insulated wire and a wire harness which are provided with such a crosslinked polymer material. A crosslinkable polymer composition comprising: a component A in which metal ions are dissociated by heat; a component B comprising an organic polymer that has a side chain and contains, in the side chain, an electron-withdrawing substituent capable of forming an ionic bond with a metal ion dissociated from the component A; and a component C which is composed of a compound having a structure represented by formula (1) and a melting point of 190 DEG C or higher, and in which a crosslinked product obtained by crosslinking the component B by metal ions free from the component A has a flow initiation temperature at 190 DEG C or higher. R represents a hydrogen atom or a hydroxyl group. M + n is from 11 to 30 (inclusive), and My + represents a y-valent metal ion.

Description

Technical Field

[0001] The present disclosure relates to a cross-linkable polymer composition, a cross-linked polymer material, an insulated electric wire, and a wiring harness. Background Art

[0002] In insulated wires and wiring harnesses, thermoplastic polymer compositions are often used as insulating components such as the insulating coating that covers the outer periphery of the wire conductor. When forming the thermoplastic polymer composition into a desired shape, it is heated to achieve a fluid state, and then a forming method such as extrusion is applied. In order to facilitate the forming process by heating, the polymer composition is preferably one that can maintain fluidity even without being heated to extremely high temperatures.

[0003] On the other hand, insulated wires and wiring harnesses experience a temperature rise when current is applied, requiring high heat resistance from polymer compositions located near the current-carrying areas, such as the insulation coating. Specifically, the polymer composition must not undergo irreversible deformation due to heat generated during current flow. For example, the insulation coating of automotive wires is expected to resist irreversible deformation at temperatures below 190°C. In particular, in electric vehicle wires, high currents must flow through the wire conductors, increasing the amount of heat generated during current flow. Therefore, high heat resistance is required for the polymer compositions that comprise the insulation coating and other components.

[0004] As such, polymer compositions used in insulated wires and wiring harnesses are required to be relatively easy to shape upon heating and to exhibit high heat resistance in the formed state. One approach to achieving both of these properties is to adjust the flow start temperature of the thermoplastic polymer used. However, polymers with high flow start temperatures require heating to high temperatures during shaping, while polymers with low flow start temperatures struggle to achieve high heat resistance, resulting in limitations. Therefore, methods utilizing crosslinking of polymer materials have also been adopted. Specifically, an uncrosslinked polymer composition is formed into a desired shape through extrusion, for example, and then the molecular chains are crosslinked to improve heat resistance. Crosslinking methods include electron beam crosslinking, which irradiates materials formed from polyolefins, etc., to crosslink the polymer chains into a three-dimensional mesh (e.g., Patent Document 1); and silane crosslinking, which involves forming a thermoplastic resin pre-introduced with reactive silane groups and then inducing crosslinking through contact with moisture (e.g., Patent Document 2). Furthermore, when using rubber as the polymer material, crosslinking caused by vulcanization can be utilized.

[0005] To perform these electron beam crosslinking, silane crosslinking, and crosslinking by vulcanization, equipment such as an electron beam irradiation device, a moisture exposure device, and a vulcanization device are required. On the other hand, as proposed by the inventors in, for example, Patent Document 3, if a metal-crosslinkable polymer composition is used that contains a component A that releases metal ions by heat, and a component B composed of an organic polymer having a substituent capable of ionically bonding with the metal ions released from component A, when the metal ions are released from component A by heat, the released metal ions ionically bond with the substituents of component B, allowing the organic polymer of component B to be crosslinked via ionic bonds.

[0006] Prior art literature

[0007] Patent Literature

[0008] Patent Document 1: Japanese Patent Application Laid-Open No. 2020-176257

[0009] Patent Document 2: Japanese Patent Application Laid-Open No. 2020-161398

[0010] Patent Document 3: International Publication No. 2021 / 193811 Summary of the Invention

[0011] Problems to be solved by the invention

[0012] In Patent Document 3, the organic polymer used as component B is primarily a resin that is liquid at room temperature or relatively low temperatures of approximately 150°C or less. A metal-crosslinked polymer composition, obtained by mixing components A and B, is applied to the surface of a metal material, etc., and then heated to produce a metal-crosslinked polymer material. It is believed that if a thermoplastic resin having a flow start temperature at a relatively high temperature, such as 190°C or higher, is used as the organic polymer instead of these liquid resins, the metal-crosslinked polymer composition can be formed into a desired shape, such as an insulation coating for an electric wire, by thermoforming, such as extrusion. It is expected that heating this formed body to crosslink the metal, thereby producing a crosslinked polymer material with excellent heat resistance.

[0013] However, when a metal-crosslinkable composition containing a thermoplastic resin is heated to a high temperature, such as 190°C or higher, for kneading and thermoforming, metal ions may be released from component A, initiating a metal-crosslinking reaction between the metal ions and component B. This can lead to a decrease in the deformability of the composition. In other words, even if the composition is thermoformed by extrusion or other methods, it may be difficult to deform into the desired shape. If the deformability of the composition decreases during heating, thermoforming may become impossible. Even if thermoforming is possible, the molding speed cannot be increased, resulting in a reduced amount of molded products produced within a given period of time, potentially leading to reduced production efficiency and excessive energy consumption.

[0014] As such, from the perspective of thermoformability, it is desirable that the material being molded maintains a high heat deformability at temperatures of 190°C or higher during thermoforming. On the other hand, from the perspective of improving the heat resistance of the resulting molded body, it is preferable to suppress heat deformability to a low level at temperatures below 190°C, which are not heated to high temperatures. In particular, when thermoforming polymer materials for applications that require heating, such as insulation coatings for wires, it is preferable to use a material that has low heat deformability at temperatures below the molding temperature but high heat deformability at temperatures above the molding temperature, in order to achieve a balance between manufacturability and heat resistance.

[0015] In view of the above circumstances, an object is to provide a cross-linkable polymer composition that can be cross-linked by heating and can be transformed from a state with low heat deformability to a state with high heat deformability at a certain temperature, a cross-linked polymer material obtained by cross-linking such a cross-linkable polymer composition, and an insulated wire and a wiring harness comprising such a cross-linked polymer material.

[0016] Means for solving problems

[0017] The cross-linkable polymer composition involved in the present disclosure includes: component A, which releases metal ions by heat; component B, which is composed of an organic polymer, the organic polymer having a side chain, and the side chain contains an electron-withdrawing substituent capable of forming an ionic bond with the metal ions released from the component A; and component C, which is composed of a compound having a structure represented by the following formula (1) and a melting point of 190°C or above, and the cross-linked body obtained by cross-linking the component B using the metal ions released from the component A has a flow start temperature of above 190°C.

[0018]

[0019] Here, R represents a hydrogen atom or a hydroxyl group. m and n are each an integer greater than or equal to 1, and m+n is greater than or equal to 11 and less than or equal to 30. y+ It represents a metal ion with a valence of y, where y is an integer greater than or equal to 1, and x=y.

[0020] The cross-linked polymer material according to the present disclosure is formed by cross-linking the cross-linkable polymer composition, and includes the component C and a cross-linked product obtained by cross-linking the component B using metal ions released from the component A.

[0021] The insulated wire according to the present disclosure includes a wire conductor and an insulating coating layer. The insulating coating layer is made of the cross-linked polymer material and covers the outer periphery of the wire conductor.

[0022] The present disclosure relates to a wiring harness including the insulated electric wires.

[0023] Effects of the Invention

[0024] The crosslinkable polymer composition disclosed herein is capable of forming crosslinks upon heating and can transition from a low heat deformability state to a high heat deformability state at a certain temperature. The crosslinked polymer material disclosed herein is a crosslinked polymer material obtained by crosslinking such a crosslinkable polymer composition. Furthermore, the insulated wire and wiring harness disclosed herein are insulated wires and wiring harnesses comprising such a crosslinked polymer material. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] [ Figure 1 ] Figure 1 A to 1C are diagrams illustrating the behavior of a crosslinked body contained in a crosslinked polymer material according to one embodiment of the present disclosure when heated. Figure 1 A. Figure 1 B. Figure 1 C shows the state where the temperature gradually increases. 2+ represents a metal ion, and R represents a side chain (independent of M and R in formula (1)).

[0026] [ Figure 2 ] Figure 2 It is a cross-sectional view showing the structure of an insulated wire according to one embodiment of the present disclosure.

[0027] [ Figure 3 ] Figure 3 The infrared absorption spectra of compositions containing components A, B, and C during kneading are shown. Each spectrum during kneading is shown as a difference spectrum obtained by subtracting the spectrum of a composition not containing component C. Furthermore, the infrared absorption spectrum of component C alone is shown at the top for reference. DETAILED DESCRIPTION

[0028] [Description of Embodiments of the Present Disclosure]

[0029] First, embodiments of the present disclosure will be described below. The crosslinkable polymer composition, crosslinked polymer material, insulated wire, and wiring harness according to the present disclosure have the following configurations.

[0030] [1] The crosslinkable polymer composition involved in the present disclosure comprises: a component A which releases metal ions by heat; a component B which is composed of an organic polymer having a side chain and containing an electron-withdrawing substituent capable of forming an ionic bond with the metal ions released from the component A; and a component C which is composed of a compound having a structure represented by the following formula (1) and a melting point of 190°C or above, wherein the crosslinked product obtained by crosslinking the component B with the metal ions released from the component A has a flow start temperature of 190°C or above.

[0031]

[0032] Here, R represents a hydrogen atom or a hydroxyl group. m and n are each an integer greater than or equal to 1, and m+n is greater than or equal to 11 and less than or equal to 30. y+ It represents a metal ion with a valence of y, where y is an integer greater than or equal to 1, and x=y.

[0033] The crosslinkable polymer composition disclosed herein can crosslink component B via metal ions released from component A by heating. Therefore, while the uncrosslinked composition exhibits high processability, the crosslinked product formed by heating can easily yield a polymer material with high heat resistance. In particular, by setting the flow initiation temperature of the crosslinked product to 190°C or higher, the crosslinked polymer material is guaranteed to have high heat resistance. Highly heat-resistant materials with a flow initiation temperature of 190°C or higher are particularly suitable for forming insulating coatings for automotive electrical wires. Furthermore, since the crosslinked structure in the crosslinkable polymer composition disclosed herein is formed by ionic bonds, crosslinking is less likely to cause a decrease in flexibility compared to crosslinking structures formed by covalent bonds. Consequently, the polymer material is less likely to become hardened by crosslinking. For example, even when forming the insulating coating of a large-diameter electrical wire, the insulating coating's flexibility is less likely to decrease when bent.

[0034] Furthermore, the crosslinkable polymer composition of the present disclosure contains a component C having the structure of the above formula (1). The melted and liquefied component C serves to improve the fluidity of the crosslinked product composed of components A and B and to improve the heat deformability of the crosslinkable polymer composition. Therefore, when the crosslinkable polymer composition is subjected to heat forming such as kneading and extrusion, even before or during forming, even if components A and B have formed a crosslinked product, the composition maintains a high fluidity due to the contribution of component C, making it easier to heat form the composition into the desired shape. The improvement in heat deformability caused by component C occurs only when component C is liquefied. Therefore, the crosslinkable polymer composition can be transformed into a state with high heat deformability in a high temperature range, with the melting point of component C as the boundary. On the other hand, the improvement in heat deformability caused by component C is a reversible phenomenon. However, since the melting point of component C is above 190°C, the crosslinked polymer material remains resistant to deformation at temperatures below 190°C, exhibiting high heat resistance.

[0035] Furthermore, in the crosslinked product formed from the crosslinkable polymer composition of the present disclosure, since the crosslinked structure is formed via ionic bonds between the substituents of the organic polymer component B and the metal ions, the crosslinked polymer material can be reshaped upon heating, utilizing the reversibility of the ionic bonds. This is because, upon reheating the already formed crosslinked product, the crosslinking points caused by the ionic bonds shift, causing the material to fluidize. Here, since the substituents introduced into the organic polymer component B are electron-withdrawing groups, a stable crosslinked structure is formed, and the crosslinked product exhibits high heat resistance. Furthermore, by introducing these substituents into the side chains of the organic polymer, the degree of freedom of thermal motion of the crosslinked sites is increased, thus facilitating the movement of the crosslinking points upon heating, resulting in excellent reshapeability of the crosslinked product. Furthermore, since the crosslinkable polymer composition contains a component C that improves heat deformability, even when the crosslinked product is reshaped, it can be easily reshaped by heating it to a temperature above the melting point of the component C, utilizing the effect of the improved heat deformability brought about by the component C. The fluidization of the cross-linked body and the improvement in the fluidity of the cross-linked body by the component C are both reversible phenomena. Therefore, if heating is stopped after reforming and the body is naturally cooled, the reformed shape can be stably maintained.

[0036] [2] In the embodiment of [1] above, the melting point of the component C and the flow start temperature of the cross-linked body may be 300°C or lower. Thus, the temporarily cross-linked material can be transformed into a highly fluid state by heating at 300°C or lower, thereby ensuring high reformability at 300°C or lower.

[0037] [3] In the embodiment of [1] or [2] above, the component A may have a decomposition point or phase transition point at a temperature below the melting point of the component C. Thus, by heating the crosslinkable polymer composition to a temperature above the melting point of the component C, a crosslinked body can be formed from the metal released from the component A and the component B, and the crosslinkable polymer composition can be formed into a desired shape by heat forming such as extrusion. In this case, heat forming such as extrusion is performed after the crosslinked body has already been formed, but the coexistence of the molten component C and the crosslinked body improves the fluidity of the crosslinked body, and high heat formability can be obtained. Therefore, the desired shape can be smoothly formed.

[0038] [4] In any of the above aspects [1] to [3], the component A may have a decomposition point or a phase transition point at 50°C or higher and 300°C or lower. Thus, during the preparation of the crosslinkable polymer composition or before use of the crosslinkable polymer composition, the release of metal ions from the component A can be suppressed, thereby suppressing the progress of crosslinking and suppressing changes in the quality of the crosslinkable polymer composition at low temperatures such as room temperature, thereby achieving high storage stability in the crosslinkable polymer composition. Meanwhile, at an appropriate temperature, the component A decomposes or undergoes a phase transition, and the metal ions are easily released from the component A, allowing the crosslinking reaction to proceed at a temperature that does not cause deterioration of the component B.

[0039] [5] In any of the above aspects [1] to [4], in the component C, x=y=1. In this case, since the component C is monovalent, the melting point of the component C is increased, and high heat resistance can be obtained in the crosslinked body formed by crosslinking. In addition, even when heated to a high temperature, the component C does not cause crosslinking between the component C and the component B. Therefore, the component C is unlikely to affect the crosslinking structure of the component B caused by the component A or the fluidity of the component B.

[0040] [6] In any of the above aspects [1] to [5], the component B may have a flow start temperature within the range of 50°C to 190°C. Thus, a crosslinked product having a flow start temperature of 190°C to 300°C can be easily obtained through crosslinking by the metal ions from the component A. Furthermore, when the uncrosslinked crosslinkable polymer composition is formed into a desired shape by extrusion molding or the like, the heat deformability-enhancing effect of the component C can be utilized to achieve high moldability.

[0041] [7] In any of the above embodiments [1] to [6], the component A may have a decomposition point or a phase transition point at a temperature above the flow start temperature of the component B. Thus, while the component B has already acquired fluidity, metal ions are released from the component A and the accompanying cross-linking of the component B occurs. Therefore, by utilizing the flow of the component B, the dispersibility of the component A in the component B can be improved, and a cross-linked product can be obtained in which cross-linking points are formed with high spatial uniformity. Furthermore, in the preparation of the cross-linkable polymer composition, the unintended release of metal ions from the component A and the accompanying cross-linking of the component B are less likely to occur.

[0042] [8] In any one of the above aspects [1] to [7], the component A may be a metal complex containing a ligand having a structure represented by the following formula (2).

[0043]

[0044] Here, R1 and R2 each independently represent a hydrocarbon group having 1 to 8 carbon atoms, and R3 represents a hydrogen atom or a hydrocarbon group having 1 to 8 carbon atoms. This also includes a case where at least two of R1, R2, and R3 are linked to each other via a ring structure.

[0045] The β-diketone ligand represented by formula (2) is a bidentate ligand and has an excellent effect on stabilizing metal ions compared to monodentate ligands and ligands forming a bridged coordination structure. It can suppress the release of metal ions from component A during the preparation of the cross-linkable polymer composition and before the use of the cross-linkable polymer composition, and can also achieve particularly high storage stability.

[0046] [9] In any of the above embodiments [1] to [8], the metal ions released from the component A may be ions of at least one of alkaline earth metals, aluminum, zinc, titanium, and zirconium. The ions of these metals all have a valence of 2 or more and easily form a stable cross-linked structure between the polymer chains of the component B. Furthermore, the ions of these metals belong to hard acids in the HSAB theory and have a high ionization tendency, forming a stable bond between the metal ions and the substituents of the component B. Therefore, they are also suitable as metals for forming a cross-linked body.

[0047]

[10] In any of the above embodiments [1] to [9], the substituent of the component B may be at least one of a carboxylic acid group, an acid anhydride group, a phosphoric acid group, and an acrylic acid group. These substituents easily form ionic bonds with the metal ions released from the component A. In addition, since these substituents are acidic groups with relatively low polarity, they are less likely to cause phase separation in the main chain and side chain of the component B, and a cross-linked structure with high spatial uniformity can be formed.

[0048]

[11] In any of the above embodiments [1] to

[10] , the substituent of the component B may be bonded to the main chain via an alkyl group or alkylene group having 1 or more carbon atoms. This allows the crosslinking site to have a particularly high degree of freedom in thermal motion, and facilitates the movement of the crosslinking point during heating, thereby achieving particularly high reshapeability.

[0049]

[12] In any of the above embodiments [1] to

[11] , the component B may not contain an electron-withdrawing group in the main chain. Thus, the side chain substituents will not be hindered from forming ionic bonds with the metal ions from the component A due to competition with the electron-withdrawing groups in the main chain. Due to steric hindrance, it is difficult for the substituents in the main chain to form a stable cross-linked structure between the substituents in the main chain and the metal ions. Even if a cross-linked structure is formed, the freedom of movement of the cross-linked site is reduced, making it difficult to obtain high reshaping properties in the cross-linked product. It is also difficult to obtain the effect of improving the fluidity of the cross-linked product brought about by the component C.

[0050]

[13] In any of the embodiments [1] to

[12] above, the crosslinkable polymer composition may contain 0.1 to 30 parts by mass of component A, with the total amount of component A, component B, and component C being 100 parts by mass. Thus, by containing a sufficient amount of component A, the crosslinking density becomes high, and the crosslinkable polymer composition exhibits excellent crosslinking properties. On the other hand, the influence of a large amount of component A is easily avoided in the material before and after crosslinking.

[0051]

[14] In any of the embodiments [1] to

[13] above, the total amount of the component A, the component B, and the component C is set to 100 parts by mass, and the crosslinkable polymer composition may contain 1.0 part by mass or more and 30 parts by mass or less of the component C. Thus, a high effect can be achieved in terms of improving the heat deformability of the crosslinkable polymer composition due to the liquefied component C. On the other hand, the phenomena of reduced physical properties such as material strength and low-temperature characteristics and increased elastic modulus, which may occur when a large amount of component C is contained in the crosslinked material, are less likely to occur.

[0052]

[15] The cross-linked polymer material of the present disclosure is composed of a material obtained by cross-linking the cross-linkable polymer composition of any one of [1] to

[14] above, and comprises the component C and a cross-linked product obtained by cross-linking the component B using the metal ions released from the component A. The cross-linked product formed by cross-linking the component B via the metal ions released from the component A has a cross-linking point at the position of the electron-withdrawing substituent introduced into the side chain of the component B and has a flow starting temperature of 190°C or above, so the cross-linked polymer material has both high heat resistance and reshapeability due to heating. In addition, the reduction in flexibility due to cross-linking is not likely to occur. In the cross-linked polymer material, most of the component C exists without entering the cross-linked structure, but when the cross-linked polymer material is heated to a temperature above the melting point of the component C, the cross-linked polymer material becomes a state with high heat deformability due to the contribution of the component C. Therefore, when the cross-linked polymer material is formed into a desired shape or reshaped, high formability can be obtained. On the other hand, since the melting point of component C is 190° C. or higher, the heat deformation property does not increase at temperatures below 190° C., so the shape of the cross-linked polymer material is stably maintained, and high heat resistance is exhibited.

[0053]

[16] The insulated wire involved in the present disclosure comprises a wire conductor and an insulating coating, wherein the insulating coating is composed of the cross-linked polymer material of

[15] and covers the outer periphery of the wire conductor. In the insulated wire, the insulating coating is composed of the cross-linked polymer material of the present disclosure, thereby showing high heat resistance. Even if the wire conductor is heated by electricity, it is not easy to produce irreversible deformation. On the other hand, if the insulating coating is heated to a sufficient temperature, the insulating coating can be fluidized again and reshaped, and the shape of the insulating coating can be changed. For example, when the wire conductor is deformed, the insulating coating is also easy to deform following the shape of the wire conductor. In particular, since the cross-linked polymer material is a material containing a C component, the effect of improving the heat deformability of the cross-linked polymer material brought about by the C component can be utilized to effectively implement the formation of the insulating coating by extrusion molding and the reshaping of the insulating coating by heating. Furthermore, since the material's flexibility is less likely to decrease due to cross-linking, the insulating coating can be made highly flexible, and even when the electric wire is formed thick, it can be easily arranged with bending.

[0054]

[17] In the embodiment of

[16] above, the electric wire conductor may be formed by twisting a plurality of single wires, and the insulated electric wire may have a flat portion in which the cross section of the electric wire conductor is flat and perpendicular to the axial direction. From the perspective of space saving, etc., an electric wire having a flat portion is required. By utilizing the reshaping property of the insulating coating, a force is applied to a conventional insulated electric wire with a circular cross section to compress it into a flat shape while the insulating coating is heated, and the flat portion can be easily formed. In addition, conversely, by applying a force in a direction to eliminate the flat shape to the electric wire in which the flat portion is formed while the insulating coating is heated, the insulated electric wire can be deformed into a state having another cross-sectional shape such as a circular cross section. In this way, by using an insulated electric wire having an electric wire conductor formed by twisting a plurality of single wires and easily deformed by applying a force, and an insulating coating that is reversibly transformed into a reshaping state by heating, it is possible to easily perform deformation between a state with a low degree of flatness such as a circular cross section and a flat state in both directions. For example, a common insulated electric wire can be used to obtain a variety of insulated electric wires in which a desired portion is deformed into a desired shape such as a flat shape according to the configuration location and application.

[0055]

[18] The wiring harness of the present disclosure includes the insulated wire of

[16] or

[17] . As described above, the insulated wire of the present disclosure has an insulating coating layer that is excellent in heat resistance and formability during initial forming and re-forming, and these properties can be utilized even in a wiring harness.

[0056] [Details of embodiments of the present disclosure]

[0057] Hereinafter, a crosslinkable polymer composition, a crosslinked polymer material, an insulated wire, and a wiring harness according to embodiments of the present disclosure will be described with reference to the accompanying drawings. It should be noted that the present disclosure is not limited to these embodiments.

[0058] [1] Cross-linkable polymer composition and cross-linked polymer material

[0059] The cross-linkable polymer composition according to the embodiment of the present disclosure comprises: a component A which releases metal ions by heat; a component B which has an electron-withdrawing substituent in its side chain that can form an ionic bond with the metal ions released from component A; and a component C which is composed of a compound having a structure represented by the following formula (1) and a melting point of 190° C. or above.

[0060]

[0061] Here, R represents a hydrogen atom or a hydroxyl group. m and n are each an integer greater than or equal to 1, and m+n is greater than or equal to 11 and less than or equal to 30. y+ It represents a metal ion with a valence of y, where y is an integer greater than or equal to 1, and x=y.

[0062] The cross-linkable polymer composition involved in this embodiment forms a cross-linked body obtained by cross-linking component B using metal ions released from component A by heating, constituting the cross-linked polymer material involved in the embodiment of the present disclosure. The cross-linked polymer material contains the cross-linked body and component C. The cross-linked body has a flow start temperature of 190°C or above. It should be noted that in this specification, the cross-linkable polymer composition basically refers to a state in which a cross-linked body is not formed, but materials that are in a state in which a certain degree of cross-linking is performed during heat forming such as heat kneading and extrusion molding are also included in the cross-linkable polymer composition.

[0063] (1) Characteristics of cross-linkable polymer compositions and cross-linked polymer materials

[0064] Before describing in detail the components that make up the crosslinkable polymer composition, the characteristics of the crosslinkable polymer composition and the crosslinked polymer material will be described. The crosslinkable polymer composition involved in this embodiment includes: component A, which releases metal ions by heat; component B, which has a substituent that can form an ionic bond with the metal ion; and component C, which has a structure represented by formula (1) and a melting point of 190°C. When the crosslinkable polymer composition containing these components is heated, metal ions are released from component A. As a result, the released metal ions form ionic bonds with the substituents of component B, and the organic polymer chains of component B are crosslinked via the ionic bonds. On the other hand, component C is a neutral molecule. Unlike component A, since the organic acid portion is stably bound to the metal, even if heated, almost no metal ions are released, and crosslinking of component B caused by component C itself or the metal from component C almost does not occur. There is also no situation where component C hinders the crosslinking of component B caused by the metal ions from component A. In the cross-linked polymer material, most of the component C does not enter the cross-linked body, and coexists with the cross-linked body while maintaining the molecular structure represented by formula (1).

[0065] Component A is a component that releases metal ions upon heating. Until the temperature at which component A releases metal ions through decomposition and phase transition, metal ions will not be released from component A, and crosslinking of the organic polymer of component B due to ionic bond formation will not occur. Therefore, the crosslinkable polymer composition of this embodiment is in a relatively high fluidity state at low temperatures, where metal ions from component A and the resulting crosslinking of component B are not caused, and can be easily formed into a desired shape by extrusion or the like. Furthermore, the crosslinkable polymer composition can be formed into the desired shape, and then heated to release metal ions from component A and crosslink component B, thereby forming a crosslinked product. Alternatively, as described later, since component C improves the fluidity and thermal deformability of the crosslinked product, the crosslinked product can also be formed into the desired shape by extrusion or the like after or while the crosslinked product is formed.

[0066] Crosslinked polymers improve heat resistance compared to the state before crosslinking by crosslinking adjacent polymer chains of component B. In the crosslinked polymer, the organic polymer chains of component B are crosslinked via ionic bonds, and their bonding force is stronger than van der Waals forces, effectively improving the heat resistance and mechanical toughness of the crosslinked polymer. On the other hand, compared to the case where the crosslinked structure is formed by covalent bonds, the reduction in flexibility caused by crosslinking is less likely to occur. In particular, when using a highly flexible organic polymer as component B, the crosslinked polymer material also has high flexibility.

[0067] The crosslinkable polymer composition according to this embodiment forms a crosslinked polymer material having particularly high heat resistance, due to the crosslinked body having a flow initiation temperature of 190°C or higher. Specifically, the crosslinked body is less likely to experience an increase in fluidity and the accompanying irreversible deformation at temperatures below 190°C. A heat resistance temperature of 190°C is generally desired for the insulation coating of automotive insulated wires. As described in detail below, the crosslinked polymer material according to this embodiment can be suitably used to form the insulation coating of automotive insulated wires. To effectively improve the heat resistance of the crosslinked polymer material, the flow initiation temperature of the crosslinked body is more preferably 200°C or higher, and further preferably 220°C or higher. It should be noted that the flow initiation temperature of the crosslinked body and component B (described below) refers to the temperature at which the material begins to exhibit fluidity when heated in a solid state. For example, as shown in the examples below, it can be measured as the temperature at which an indenter can penetrate a sheet of material. Alternatively, the flow initiation temperature can be considered the melting point or flow point (or the lower of both).

[0068] Furthermore, in the crosslinkable polymer composition according to this embodiment, the crosslinking structure between the polymer chains of component B is formed not by irreversible covalent bonds as in electron beam crosslinking or silane crosslinking, but by reversible ionic bonds with metal ions. Therefore, the resulting crosslinked polymer material exhibits reshapeability. Specifically, by heating the crosslinked polymer material, which has been temporarily crosslinked, the crosslinked polymer material regains its fluidity and can be formed into a shape different from that before heating by applying an external force, for example.

[0069] The reshaping property of cross-linked polymer materials can be explained by the following mechanism. The cross-linked polymer obtained by cross-linking the polymer chains of component B with metal ions is in a state of room temperature or near room temperature without being heated. Figure 1 As shown in A, in the chain of component B, the crosslinking points caused by metal ions are localized at certain positions. However, when the crosslinked body is heated, the molecular motion of component B caused by heat becomes active, as shown in Figure 1 As shown in B, active thermal motion occurs at and near the cross-linking site where the substituent of component B forms an ionic bond with the metal ion. When the cross-linked body is heated to a higher temperature, the molecular motion of component B is further activated, and the cross-linking point via the metal ion can move to a different site nearby (the position of other substituents), thereby delocalizing the cross-linking point. Delocalization occurs through the cross-linking point, such as Figure 1 As shown in Figure C, a state (multidentate) in which multiple substituents in the same molecular chain of component B are coordinated to a metal ion at the same time is formed. By the activation of the thermal motion in such component B and the subsequent movement of the crosslinking point, the crosslinked body becomes able to flow. Under these conditions, by appropriately applying an external force to the material, the crosslinked polymer material can be reshaped. The activation of the thermal motion of the crosslinking site and the delocalization of the crosslinking point are reversible phenomena. If the crosslinked polymer material after reshaping is cooled, the crosslinking point returns to the state of localization, returning to the state of a thermally stable crosslinked body. By repeated heating and cooling, the crosslinked polymer material can also be repeatedly reshaped. It should be noted that the activation of the thermal motion of the crosslinking site caused by heating and the delocalization of the crosslinking point can be confirmed, for example, by infrared absorption spectroscopy. Typically, in the spectrum, the activation of the thermal motion of the crosslinking site is manifested as the broadening of the absorption peak of the substituent forming the crosslinked structure. In addition, the delocalization of the crosslinking point is manifested as the growth of a new peak corresponding to multidentate.

[0070] Furthermore, in the crosslinkable polymer composition according to this embodiment, component B contains a substituent capable of forming an ionic bond with a metal ion in a side chain rather than in the polymer main chain. This allows for a high degree of freedom of movement at the crosslinked site when a crosslinked structure via the metal ion is formed. As a result, thermal motion of the crosslinked site and migration of the crosslinking point occur particularly readily in the crosslinked product. Consequently, the crosslinked polymer material exhibits high reshaping properties upon heating.

[0071] In particular, in the crosslinkable polymer composition according to this embodiment, the flow initiation temperature of the resulting crosslinked product is preferably suppressed to 300°C or lower. This allows the crosslinked polymer material to be reshaped easily and easily by heating it to a maximum temperature of 300°C. From the perspective of effectively improving reshapeability, the flow initiation temperature of the crosslinked product is more preferably 280°C or lower, and further preferably 250°C or lower.

[0072] As described above, the crosslinkable polymer composition according to this embodiment contains a component A that releases metal ions upon heat, and a component B having a substituent in its side chain that can form an ionic bond with the metal ion. Furthermore, the crosslinked product obtained by crosslinking component B due to the metal ions released from component A has a flow start temperature of 190°C or higher, more preferably 300°C or lower, thereby providing a crosslinked polymer material having high heat resistance and further reformability. Due to these properties, the crosslinkable polymer composition according to this embodiment can be suitably used in components such as insulating coatings of insulated wires that require high heat resistance and benefit from reformability. Furthermore, in the crosslinked polymer material, as another indicator indicating that the effect of improving heat resistance due to crosslinking is sufficiently exhibited, the flow start temperature of the crosslinked polymer material is preferably 5°C or higher, and further 10°C or higher, than the flow start temperature of component B alone.

[0073] As described above, the cross-linkable polymer composition involved in this embodiment has high heat resistance and re-formability by forming an ionically bonded cross-linked structure by components A and B. However, by containing component C in addition to components A and B, it is possible to further improve the formability during initial forming and re-forming while maintaining high heat resistance. Component C, as shown in the above formula (1), has a structure in which a long-chain organic acid and a metal are combined. When the temperature reaches a high temperature, it has the effect of improving the fluidity of the cross-linked body composed of components A and B. It is believed that this is because the binding between the organic acid of component C and the metal is weakened by heating, and an anion field of the organic acid is formed over a wide range. The anion field interacts with the metal cross-linked parts of the cross-linked body formed by the metal from component A and component B. It is believed that by forming an ionically bonded interaction between the anion field and the metal ions constituting the cross-linked body, the binding between the metal ions and the substituents of component B is weakened, thereby facilitating the movement of the polymer chains of component B constituting the cross-linked body. That is, through the anion field brought by component C, the cross-linked body is connected to the metal in a wider range. Figure 1 The delocalization of the cross-linking points shown in C is similar to the delocalization of the cross-linking points.

[0074] When a crosslinkable polymer composition is subjected to heat forming such as extrusion molding, crosslinking may sometimes occur between component A and component B due to heating during the heat mixing and forming steps prior to molding. This reduces the fluidity of the crosslinkable polymer composition, potentially causing difficulties during mixing and forming. However, since the crosslinkable polymer composition contains component C, even if a crosslinked body is formed in this manner, the fluidity of the crosslinked body is improved, and the heat deformability of the crosslinkable polymer composition is increased, thereby enabling smooth and efficient heat forming such as heat mixing and extrusion molding. Consequently, high effects can be achieved in terms of improving the production efficiency of the molded body and reducing energy consumption during molding.

[0075] The improvement in the fluidity of the crosslinked body brought about by component C only occurs when component C melts and becomes liquid. At temperatures below the melting point of component C, even if component C coexists with the crosslinked body, the crosslinked body remains in a state of low fluidity and stably maintains a predetermined shape. That is, with the melting point of component C as the boundary, the crosslinked body reversibly transitions between the low-temperature state on the side where the fluidity and heat deformability of the crosslinked body are low and the high-temperature state on the side where the fluidity and heat deformability of the crosslinked body are improved. That is, when the crosslinkable polymer composition is heat-formed, when heated to a temperature above the melting point of component C, even if a crosslinked body is formed between components A and B, it can be formed under a state where the heat deformability is improved due to the contribution of component C. In addition, when the crosslinked polymer material obtained by crosslinking and forming into a predetermined shape is heated to a temperature above the flow start temperature of the crosslinked body and above the melting point of component C, the fluidity obtained by the crosslinked body is enhanced by component C, and the reshaping of the crosslinked polymer material can be effectively implemented. On the other hand, at temperatures below the melting point of component C, component C does not increase the fluidity of the crosslinked product, thereby maintaining the crosslinked polymer material in a state of low heat deformation and high thermal stability. Component C is unlikely to become a substance that impairs the heat resistance of the crosslinked product.

[0076] As described above, component C transitions the crosslinkable polymer composition and crosslinked polymer material from a low heat deformability state to a high heat deformability state at the melting point. However, since component C has a melting point of 190°C or higher, it does not increase the heat deformability of the crosslinked polymer material unless heated to temperatures exceeding 190°C. Therefore, combined with the effect of the crosslinked body's flow initiation temperature being 190°C or higher, the crosslinked polymer material maintains a low heat deformability state at temperatures below 190°C, stably retaining the intended molded shape. In other words, the crosslinked polymer material exhibits high heat resistance. Therefore, the crosslinked polymer material can be suitably used in applications requiring heat resistance of approximately 190°C, such as insulation coatings for insulated wires for automobiles.

[0077] As the degree of improvement in heat deformation brought about by component C, the heat deformation rate of the cross-linked polymer material at 190°C or above, for example, 210°C, is preferably 80% or more, and more preferably 90% or more. The higher the heat deformation rate at 190°C or above, the more preferred, and no upper limit is particularly set. On the other hand, from the viewpoint of maintaining high heat resistance, the heat deformation rate of the cross-linked polymer material at a temperature below 190°C, for example, at 170°C, is preferably 20% or less, and more preferably 10% or less. The lower the heat deformation rate at a temperature below 190°C, the more preferred, and no lower limit is particularly set. In addition, the ratio of the heat deformation rate at 210°C to the heat deformation rate at 170°C (210°C deformation rate / 170°C deformation rate; deformation rate ratio) can be 5 or more, and more preferably 10 or more. The larger the deformation rate ratio, the greater the difference between the heat deformation rates below 190°C and above 190°C. Furthermore, a larger deformation ratio makes it easier to control the state of the cross-linked polymer material at 190°C, achieving a high effect in achieving both heat resistance below 190°C and improved formability above 190°C. A larger deformation ratio is more preferable, but there is no particular upper limit. The heating deformation ratio of the cross-linked polymer material at various temperatures can be evaluated using the method used in the examples below.

[0078] In the present embodiment, the cross-linked polymer material obtained by cross-linking component B can have a wide range of tensile modulus according to the tensile modulus of the polymer material used as component B, and there is no particular restriction on the specific tensile modulus. However, in the case of particularly wanting to obtain high flexibility, the tensile modulus of the cross-linked polymer material is preferably below 100 MPa. Thus, the cross-linked polymer has high flexibility. It is further preferred that the tensile modulus is below 50 MPa, and further can be below 20 MPa. The lower limit of the tensile modulus of the cross-linked polymer material is not particularly specified, but from the viewpoint of ensuring sufficient mechanical strength, it can be above 5 MPa, and further above 10 MPa. On the other hand, in the cross-linked polymer material, in the case of particularly wanting to improve mechanical strength, the tensile modulus can be made higher than 100 MPa. In this case, from the viewpoint of ensuring flexibility, the tensile modulus can also be suppressed to below 1600 MPa.

[0079] As described above, in the crosslinkable polymer composition according to this embodiment, in order to obtain a crosslinked polymer material having high heat resistance and reshapeability through crosslinking, it is important that the crosslinked product has a flow onset temperature within a predetermined range. The flow onset temperature of the crosslinked product is determined by factors such as the type of metal ions released from component A, the polymer backbone and side chains of component B, the type and structure of substituents, and the ratio of components A to B. Furthermore, the type of component C affects the degree of heat deformability imparted by component C and the temperature at which heat deformability increases. The preferred structures and properties of each component are described below in order.

[0080] (2)A component

[0081] Component A is a component that releases metal ions when heated. Heating refers to the assumption of heating, assuming a temperature higher than room temperature. Release of metal ions means that component A undergoes decomposition or phase change, releasing metal ions from component A. The metal ions released from component A cause crosslinking of component B.

[0082] Component A preferably has a decomposition point or phase transition point at 50°C or above. As a result, when preparing a crosslinkable polymer composition or before using the crosslinkable polymer composition (before crosslinking), it is easy to suppress the release of metal ions from component A, and the progress of crosslinking of component B can be suppressed, so that the storage stability of the crosslinkable polymer composition is excellent. That is, when components A and B are mixed at a low temperature of less than 50°C to prepare a crosslinkable polymer composition, or when the prepared crosslinkable polymer composition is stored, it is not easy to cause unexpected release of metal ions from component A and the accompanying crosslinking of component B, etc., which deteriorates the quality of the crosslinkable polymer composition. When component A has a decomposition point or phase transition point at 60°C or above, and further at 70°C or above, the effect of improving storage stability is further improved.

[0083] On the other hand, component A preferably has a decomposition point or phase transition point at 300°C or lower. This reduces the likelihood of component B degrading at temperatures lower than the temperature at which metal ions are released from component A, making it easier to crosslink the undegraded component B with the metal ions. Furthermore, by decomposing or undergoing a phase transition at an appropriate temperature, component A facilitates the release of metal ions from component A, resulting in an excellent crosslinking rate for the crosslinkable polymer composition. From these viewpoints, it is more preferable for component A to have a decomposition point or phase transition point at 200°C or lower, further preferably at 150°C or lower, or 120°C or lower.

[0084] In addition, it is preferred that component A have a decomposition point or phase transition point at a temperature above the flow start temperature of component B, which will be described later. Thus, at a temperature at which component A liberates metal ions, component B can proceed to crosslink component B due to the metal ions liberated from component A while component B has already achieved fluidity. Therefore, crosslinking can be performed while metal ions are well dispersed in component B, utilizing the fluidity of component B. This makes it easier to obtain a crosslinked polymer material with highly uniform structural structure and highly spatially distributed crosslinking points caused by metal ions. Furthermore, during the preparation of the crosslinkable polymer composition, it is less likely that metal ions will be liberated from component A and that crosslinking of component B will proceed as a result. More preferably, component A can have a decomposition point or phase transition point at a temperature higher than the flow start temperature of component B, and further, component A can have a decomposition point or phase transition point at a temperature 10°C or higher than the flow start temperature of component B. It should be noted that the decomposition point or phase transition point of component A is represented by the baseline change onset temperature based on differential scanning calorimetry (DSC) (measurement temperature range: 25°C to 200°C, measured in air). The phase transition point does not include the melting point, and the phase transition does not include melting. If component A has both a phase transition point and a decomposition point, or if it has multiple phase transition points, the lower of these (the lowest) will be treated as the "decomposition point or phase transition point."

[0085] As described above, in a crosslinkable polymer composition, the effect of component C on improving the heat deformability of the crosslinkable polymer composition is most effective when components A and B have already formed a crosslinked body or are in the process of forming a crosslinked body. Therefore, to effectively utilize the improved heat deformability brought about by component C, the decomposition point or phase transition point of component A, which is the temperature at which crosslinking can begin, is preferably below the melting point of component C, and more preferably below 190°C. Thus, in a crosslinkable polymer composition containing components A and B, high formability can be utilized when a crosslinked body is formed during kneading and then subjected to heat forming such as extrusion, or when a crosslinked body is formed simultaneously with heat forming. Using these methods, a crosslinked polymer material can be obtained without the need for additional heating of the formed crosslinkable polymer composition for crosslinking.

[0086] The metal species of the metal ions released from component A are not particularly limited, and alkaline earth metals, aluminum, zinc, titanium, zirconium, etc. can be appropriately used. The metal ions released from component A can be ions of at least one of these metals. The ions of these metals have a valence of 2 or more, and by forming ionic bonds between the ions of these metals and the substituents of component B, a stable cross-linked structure is easily formed between the polymer chains of component B. In addition, the ions of the metals listed above belong to hard acids in the HSAB theory and are metals with relatively high ionization tendencies. Therefore, a stable bond is formed between the ions of the metals and the substituents of component B, making them suitable as metals for forming a cross-linked body.

[0087] Furthermore, when the crosslinkable polymer composition according to this embodiment is used to form a member that contacts a metal member, if the metal species contained in the crosslinkable polymer composition is the same as the metal species that is the main component of the metal member, the influence of the metal member on the formation and stable maintenance of the crosslinked structure at the interface between the metal member and the polymer material can be easily suppressed. For example, in an insulated wire, when the crosslinkable polymer composition according to this embodiment is used to form an insulating coating covering a wire conductor made of aluminum or an aluminum alloy, the metal ions released from component A can be set to aluminum.

[0088] The metal types listed above as preferred substances are not limited. As long as the B component is cross-linked by forming an ionic bond between the metal ion and the substituent of the B component and a cross-linked body with a flow start temperature of 190°C or above, preferably further below 300°C, any metal ion can be used as the metal ion released from the A component. However, transition metals such as iron, nickel, and copper tend to provide a cross-linked body with a flow start temperature higher than the above range. This is believed to be because when a cross-linked body is formed using ions of metals with many available oxidation numbers or low ionization tendency, such as transition metals, the movement of cross-linking points when heated is less likely to occur (see Figure 1 C). The metal ions released from component A may be not only monatomic ions of the metal but also polyatomic ions (including metal ions) formed by bonding metal atoms and other atoms. However, monatomic ions of the metal are preferred from the viewpoint of forming a stable ionic bond with the substituent of component B.

[0089] Component A can be any chemical species as long as it is a substance that frees metal ions by heat, and a metal complex can be cited as a preferred chemical species. The metal complex is composed of a substance obtained by coordination bonding between a ligand having an unshared electron pair and a metal ion as a center. When a metal complex is used, the stabilization effect of the metal ion caused by the ligand is excellent, and the metal ion can be suppressed from being freed from component A during the preparation of the crosslinkable polymer composition, before the crosslinkable polymer composition is used, and when the crosslinkable polymer composition is crosslinked, the metal ion is easily freed from component A due to heat.

[0090] As the ligand constituting the metal complex, a monodentate ligand with a coordination site of 1 and a polydentate ligand with a coordination site of 2 or more can be cited. The metal complex generated by the polydentate ligand is due to the chelating effect, and compared with the metal complex generated by the monodentate ligand, the metal complex generated by the ligand using a bridged coordination structure represented by an alkoxide ligand, the stability is excellent. Therefore, component A is preferably a metal complex comprising a polydentate ligand. Compared with the coordination caused by the monodentate ligand, the coordination caused by the ligand using a bridged coordination structure, the stabilization effect of the metal ion caused by the polydentate ligand is excellent, and when preparing the crosslinkable polymer composition, before using the crosslinkable polymer composition, it is possible to more effectively suppress the freeing of metal ions from component A.

[0091] Among the multidentate ligands, β-diketone ligands (1,3-diketone ligands) as bidentate ligands can be appropriately used. β-diketone ligands are particularly excellent in stabilizing metal ions. In addition, metal complexes with β-diketone ligands are suitable for dispersing component A in component B and forming crosslinking points with high uniformity because they are easily well dispersed in organic polymers. β-diketone ligands are represented by the following general formula (2).

[0092]

[0093] In formula (2), R1 and R2 each independently represent a hydrocarbon group, and R3 represents a hydrogen atom or a hydrocarbon group. This also includes cases where at least two of R1, R2, and R3 are linked to each other via a ring structure. Furthermore, the ligand may also adopt the structure of formula (2) via a resonance structure.

[0094] In formula (2), R1, R2, and R3 may be aliphatic hydrocarbon groups or hydrocarbon groups containing aromatic rings. Furthermore, heteroatoms such as oxygen atoms may also be contained. Examples of hydrocarbon groups constituting R1, R2, and R3 include alkyl groups, alkoxy groups, aromatic groups, and condensed aromatic groups. The number of carbon atoms in R1, R2, and R3 is not particularly limited, but each preferably has 1 or more and 8 or less.

[0095] Specific examples of β-diketone ligands include acetylacetone ligand (acac), 2,2,6,6-tetramethyl-3,5-heptanedione ligand (dpm), 3-methyl-2,4-pentanedione ligand, 3-ethyl-2,4-pentanedione ligand, 3,5-heptanedione ligand, 2,6-dimethyl-3,5-heptanedione ligand, and 1,3-diphenyl-1,3-propanedione ligand. Among these, from the perspective of structural simplicity, in the above formula (2), acetylacetone ligands in which R1 and R2 are methyl groups and R3 is a hydrogen atom are particularly preferred.

[0096] In a crosslinkable polymer composition, the total of components A, B, and C is set to 100 parts by mass, and the content of component A can be 0.1 parts by mass or greater. Thus, by containing a sufficiently large amount of component A relative to component B, the crosslink density in the crosslinked product is increased, effectively improving heat resistance. To enhance the effect of improving heat resistance, the content of component A is more preferably 1.0 parts by mass or greater, and further preferably 2.0 parts by mass or greater, relative to the aforementioned 100 parts by mass. On the other hand, the content of component A can be 30 parts by mass or less, relative to the aforementioned 100 parts by mass. This easily avoids the effects of containing a large amount of component A, such as separation and precipitation of component A before crosslinking and embrittlement of the crosslinked polymer material. Furthermore, by not containing excess component A in the crosslinkable polymer composition, the high mechanical strength of component B can be more readily utilized as a characteristic of the crosslinked polymer material as a whole. To enhance these effects, the content of component A is more preferably 20 parts by mass or less, and further preferably 10 parts by mass or less, relative to the aforementioned 100 parts by mass.

[0097] (3) Component B

[0098] Component B is composed of an organic polymer with side chains, and the side chains contain electron-withdrawing substituents capable of forming ionic bonds with the metal ions released from component A. Even if the substituents are not electron-withdrawing, they can form ionic bonds with the metal ions released from component A. However, by withdrawing electrons, they can form stable ionic bonds with the metal ions. Therefore, in a crosslinkable polymer composition, when component B is crosslinked with metal ions, a stable crosslinked structure is formed, and the crosslinked product tends to exhibit high heat resistance.

[0099] As electron-withdrawing substituents capable of forming ionic bonds with metal ions, acidic groups other than hydroxyl groups such as carboxylic acid groups, anhydride groups, phosphoric acid groups, and acrylic acid groups can be appropriately exemplified. The substituent may be only one, or two or more, and may be at least one of the substituents listed above. In particular, maleic acid groups and acrylic acid groups can be preferably used. In addition, anhydride groups such as maleic anhydride groups can also be preferably used. The substituents listed above are excellent in that they are easy to form ionic bonds with the metal ions released from component A. In addition, the substituents listed above are all acidic groups with relatively low polarity, so they are not easy to cause phase separation for the main chain and side chain of component B, have high uniformity in the organization of component B, and can form a cross-linked structure. For example, a sulfonic acid group is also an electron-withdrawing substituent that is easy to form ionic bonds with metal ions, but due to its high polarity, it is easy to cause phase separation and cannot be suitable as a substituent for component B as the substituents listed above as preferred substituents.

[0100] As mentioned above, in component B, the substituent that forms an ionic bond with the metal ion is not contained in the polymer main chain, but is contained in the side chain. As a result, when a cross-linked structure is formed, the cross-linked site maintains a high degree of freedom of movement. As a result, the cross-linked polymer material becomes a material with high reshaping properties. In addition, by including electron-withdrawing groups in the side chains, it is possible to obtain a high effect of improving the fluidity of the cross-linked body due to the contribution of the anionic field of component C. There are no particular restrictions on the structure and length of the side chains, but from the perspective of improving their effects, the substituent can be bound to the main chain via an alkyl or alkylene group having 1 or more carbon atoms. Alternatively, the substituent can be bound to the main chain via heteroatoms such as oxygen atoms. The substituent can be introduced at the end of the side chain or in the middle, but from the perspective of effectively improving the freedom of movement of the cross-linked site, it is preferably introduced at the end. There is no particular upper limit on the number of carbon atoms in the side chain, but from the perspective of minimizing the impact on the physical properties of the main chain, the number of carbon atoms connecting the main chain and the substituent can be 4 or less. In the case where the substituent is a carboxylic acid group and a phosphoric acid group, particularly preferred structures of the side chain portion are represented by the following formula (3) and formula (4), respectively.

[0101]

[0102]

[0103] Here, R4 represents the main chain, R5 represents an oxygen atom or an alkyl or alkylene group having 1 or more carbon atoms, and R6 also represents an alkyl or alkylene group having 1 or more carbon atoms. Multiple electron-withdrawing substituents may be bonded to the main chain via a common R5 or R6. Alternatively, multiple electron-withdrawing substituents may form an anhydride with each other.

[0104] In component B, the electron-withdrawing substituent may be included in the main chain or not, and may be either, as long as it is included in the side chain. However, it is preferred that the electron-withdrawing group is not included in the main chain. This is because, when the electron-withdrawing group is included in the main chain, it may hinder the electron-withdrawing group of the side chain from forming a cross-linked structure through the ionic bond between the substituent and the metal ion. The electron-withdrawing group in the main chain is easily subject to large steric hindrance, and therefore it is difficult to effectively contribute to the cross-linking caused by the formation of ionic bonds with the metal ion, and lacks the effect of improving heat resistance through cross-linking. In addition, even if a cross-linked structure is formed at the site of the electron-withdrawing group in the main chain, the freedom of movement of the cross-linked site also becomes smaller, making it difficult to obtain high re-formability. It is also difficult to obtain the effect of improving fluidity brought about by component C. As the electron-withdrawing group that is not preferably included in the main chain of component B, carboxyl groups, halogen atoms, etc. can be listed when the main chain is composed of a copolymer of (meth) acrylic acid.

[0105] In component B, the content of the substituents contained in the side chains is not particularly limited, but from the perspective of ensuring the physical properties brought about by crosslinking, it is preferably 0.01% by mass or more and 10% by mass or less relative to the total mass of component B. The content of the substituents contained in the side chains is more preferably 0.1% by mass or more and 5% by mass or less, and even more preferably 0.2% by mass or more and 3% by mass or less. The content of the substituents in component B can be determined by comparing the size of the substituent-specific peak in the infrared absorption spectrum with the size of the spectrum peak of a material with a known content.

[0106] The organic polymer of component B is an organic polymer such as resin, rubber, and elastomer. Preferably, from the viewpoint of formability during heat forming such as extrusion forming, component B can be composed of a thermoplastic resin. In particular, from the viewpoint of obtaining high formability and flexibility, the main chain of component B is preferably composed of an elastomer. Examples of elastomers include: styrene-based thermoplastic elastomers such as styrene-ethylene-butylene-styrene block copolymer (SEBS); and olefin elastomers such as ethylene-α-olefin copolymers. In addition to having high flexibility, the main chain composed of styrene-based elastomers and olefin elastomers is not easily affected by the formation of crosslinking points in the side chains, the activation of molecular motion of the crosslinking site caused by heating, the movement of crosslinking points, and the delocalization of crosslinking points caused by component C. In the side chain portion, the high heat resistance and re-formability brought about by these phenomena are effectively exerted as the overall characteristics of the crosslinked body of component B. In addition to these elastomers, suitable organic polymers that can constitute the main chain of component B include polyolefins such as polyethylene and polypropylene; and ethylene copolymers such as ethylene-methyl acrylate copolymer (EMA) and ethylene-vinyl acetate copolymer (EVA).

[0107] Component B preferably has a flow initiation temperature within the range of 50°C to 190°C. This facilitates obtaining a crosslinked product having a flow initiation temperature of 190°C or higher, preferably 300°C or lower, through crosslinking caused by the metal ions released from component A. Furthermore, when the crosslinkable polymer composition is molded by heating to a temperature above the melting point of component C (190°C or higher), the fluidity of component B (including forms already crosslinked by metal ions from component A) can be utilized to achieve high moldability. It is more preferable for component B to have a flow initiation temperature of 80°C to 160°C.

[0108] From the perspective of improving the flexibility of the cross-linked polymer material, the hardness of component B is preferably 60 or less, more preferably 50 or less, and even more preferably 40 or less in terms of Shore D hardness. On the other hand, from the perspective of ensuring the mechanical strength of the cross-linked polymer material, the hardness of component B is preferably 10 or more in terms of Shore D hardness. The Shore D hardness of component B can be measured in accordance with JIS K 6253. It should be noted that in the case of particularly improving the mechanical strength of the cross-linked polymer material, even if the Shore D hardness is within the range of 60 or less, it is preferable to use a higher material such as greater than 40 or a material further exceeding 60 as component B. However, in this case, from the perspective of ensuring the flexibility of the cross-linked polymer material, the Shore D hardness of component B can be suppressed to 70 or less.

[0109] (4) Component C

[0110] The component C is composed of a compound having a structure represented by formula (1) shown again below and having a melting point of 190° C. or higher.

[0111]

[0112] Here, R represents a hydrogen atom or a hydroxyl group. m and n are each an integer greater than or equal to 1, and m+n is greater than or equal to 11 and less than or equal to 30. y+ It represents a metal ion with a valence of y, where y is an integer greater than or equal to 1, and x=y.

[0113] As shown in formula (1), component C is composed of a long-chain organic acid and a metal. Polarization between the organic acid portion and the metal portion forms a broadly extending anionic field, delocalizing the crosslinked structure in the crosslinked product composed of the metal from component A and component B, thereby improving the fluidity of the crosslinked product. The liquefied component C acts as a plasticizer. This phenomenon occurs only when component C is liquefied. Since component C has a melting point of 190°C or higher, it only occurs at temperatures above 190°C. At temperatures below 190°C, even if component C is present, the fluidity of the crosslinked product does not improve, and the crosslinked polymer material maintains a high heat resistance. If component C has a melting point below 190°C, it will melt even at temperatures below 190°C, and the liquefied component C will act as a solvent. As described above, the delocalization of the crosslinked structure caused by the anionic field causes the crosslinked product to become highly fluid, and the heat resistance of the crosslinked polymer material cannot be maintained. From the viewpoint of improving the heat resistance of the cross-linked polymer material, the melting point of the component C is more preferably 200° C. or higher, and even more preferably 210° C. or higher.

[0114] The upper limit of the melting point of component C is not particularly specified, but is preferably 300°C or lower. Thus, even without heating to excessively high temperatures, the effect of improving the fluidity of the crosslinked product due to component C can be achieved. The melting point is more preferably 280°C or lower. Furthermore, the melting point of component C is preferably at least the flow initiation temperature of the crosslinked product composed of components A and B, and at least the decomposition point or phase transition point of component A.

[0115] The melting point of component C is different according to the crystallinity of component C based on the three-dimensional structure of the molecule, and becomes an inherent value according to the structure of the organic chain and the combination of metal species. In formula (1), component C has a sufficiently high melting point because m+n is 11 or more. In addition, component C shows high compatibility with component B or a crosslinked body composed of component B and component A because m+n is as large as 11 or more. Preferably, m+n can be 13 or more. On the other hand, by making m+n 30 or less, the melting point of component C can be suppressed from becoming too high. Preferably, m+n is 23 or less, and more preferably 17 or less. In addition, the organic acid part has a straight-chain structure. This is because the organic acid part has a straight-chain structure, the crystallinity of the organic acid part becomes high, and the melting point of component C tends to become high. In formula (1), it is preferred that R is a hydrogen atom and the organic acid portion is composed of a fatty acid. However, even if R is a hydroxyl group, the hydroxyl group will not interact with the carboxyl group of component C, the metal, or the crosslinked body composed of components A and B. Compared with the case where R is a hydrogen atom, the behavior of component C in the crosslinkable polymer composition and the crosslinked polymer material is not significantly different.

[0116] Preferred examples of the organic acid constituting the component C include the following organic acids.

[0117] ･Stearic acid (m+n=15, R=H)

[0118] ･12-Hydroxystearic acid (m=5, n=10, R=OH)

[0119] ･Behenic acid (m+n=19, R=H)

[0120] ･Montanic acid (m+n=25, R=H)

[0121] ･Heptadecanoic acid (m+n=14, R=H)

[0122] ･Palmitic acid (m+n=13, R=H)

[0123] The valence of the metal M constituting the C component is not particularly limited, but is preferably univalent. This is because being univalent by metal M, compared with the situation that metal M is more than divalent, the molecular structure of C component becomes simple, by forming a firm crystalline structure, easily imparts high melting point. In addition, even if a part of C component decomposes and releases metal ion at high temperature, and this metal ion interacts (ionic bond) with B component, if this metal ion is univalent, then it is difficult to form cross-linked structure, therefore it is difficult to the cross-linked body caused by the metal from A component is formed and the fluidity of this cross-linked body is affected. As the univalent metal constituting the C component, the alkali metal represented by Li and Na can be preferably exemplified. In the case of adopting divalent metal, the alkaline earth metal represented by Ba can be used.

[0124] As component C, it is also conceivable to use an organic acid itself, that is, a molecule in which the metal M in formula (1) is a hydrogen atom (H), or a molecule having an electron-donating organic functional group such as an amide group in place of the metal M. However, even when these molecules are heated to a high temperature, they cannot form an anion field effective for improving the fluidity of the crosslinked product. Therefore, these molecules cannot be used as component C.

[0125] In the cross-linkable polymer composition, the total of component A, component B, and component C is set to 100 parts by mass, and the content of component C can be 1.0 parts by mass or more. Thus, by forming an anion field by component C, a high effect of improving the fluidity of the cross-linked body composed of component A and component B can be obtained. It is further preferred that the content of component C can be 3.0 parts by mass or more or 5.0 parts by mass relative to the above 100 parts by mass. On the other hand, the content of component C can be 30 parts by mass or less relative to the above 100 parts by mass. Thus, the formation of aggregates of component C can be avoided. In addition, the content of component B is a relatively sufficient amount, and in the cross-linked polymer material, the physical properties brought by component B, such as mechanical strength and low-temperature characteristics, are fully manifested. It is further preferred that the content of component C can be 20 parts by mass or less, or 10 parts by mass or less relative to the above 100 parts by mass.

[0126] (5) Other ingredients

[0127] The crosslinkable polymer composition according to this embodiment may contain, in addition to the above-mentioned components A, B, and C, additives such as flame retardants, copper poison inhibitors, antioxidants, and colorants, as appropriate, within a range that does not hinder the function of the material. Examples of other additives include secondary or tertiary amines represented by the following formula (5). When this amine is added to the crosslinkable polymer composition, the rate of crosslinking of component B by component A is suppressed, and crosslinking proceeds uniformly throughout the entire material, thereby increasing the degree of crosslinking and achieving high wear resistance. The amount of amine added, based on the total of components A and B being 100 parts by mass, can be exemplified by a range of 0.5 parts by mass or more and 20 parts by mass or less.

[0128]

[0129] Here, R7 is a hydrogen atom or a hydrocarbon group having 30 or less carbon atoms, R8 is a hydrocarbon group having 30 or less carbon atoms, and R9 is a hydrocarbon group having 13 or more and 30 or less carbon atoms.

[0130] In addition, the cross-linkable polymer composition involved in this embodiment may contain organic polymers other than component B as a polymer component, but its content is preferably suppressed to be less than the content of component B. It is further preferred that the cross-linkable polymer composition contains only component B as a polymer component. As components that are preferably not contained in the cross-linkable polymer composition, the following compounds of groups (a) to (f) can be listed. That is, the following can be listed: (a) silane coupling agents, (b) epoxy compounds, (c) isocyanates / salts, isothiocyanate / salt compounds, (d) photoradical initiators, thermal radical initiators, (e) chlorine compounds, bromine compounds, (f) volatile organic solvents. When the cross-linkable polymer composition contains compounds of groups (a) to (d), when heated, it is possible to produce undesirable chemical reactions such as cross-linking of component B and breaking of the main chain of component B caused by reactions different from the cross-linking reaction via the metal ions released from component A. As a result, it is possible that the heat resistance and reshaping properties of the cross-linkable polymer composition cannot be fully exerted. Furthermore, when a crosslinkable polymer composition contains a compound of group (e), there is a risk of coloration or generation of corrosive gases due to heating. When a crosslinkable polymer composition contains a compound of group (f), there is a risk of ignition or generation of bubbles during molding of the composition.

[0131] A cross-linkable polymer composition can be prepared by mixing component A, component B, component C, and any additional components added as needed. Mixing can be performed by heat mixing. The resulting cross-linkable polymer composition can then be subjected to heat forming such as extrusion molding to form it into any shape. If heat mixing and heat forming are performed at a temperature above the decomposition point or phase transition point of component A and above the melting point of component C, the cross-linkable polymer composition can be formed into a predetermined shape while components A and B have formed a cross-linked body, or while the cross-linked body is being formed and has high fluidity. In this case, heating for cross-linking can be omitted after forming. In addition, the temperature during heat mixing and heat forming can be set to a temperature above the flow start temperature of the cross-linked body formed by components A and B. Furthermore, if the cross-linked polymer material temporarily formed into a predetermined shape is heated to a temperature above the flow start temperature of the cross-linked body and above the melting point of component C, the cross-linked polymer material acquires fluidity and can be reshaped. Reshaping can be repeated reversibly. The cross-linkable polymer composition according to this embodiment can form a cross-linked structure even without any operation other than heating. Therefore, the cross-linking process can be carried out with simpler equipment compared to electron beam cross-linking or silane cross-linking. Since the reshaping process can also be carried out by applying an appropriate external force while heating, it can also be carried out with simple equipment.

[0132] [2]Insulated wires and wiring harnesses

[0133] The cross-linked polymer material formed by the cross-linked polymer composition involved in this embodiment can be used to form any component. However, due to its high heat resistance and formability, it can be appropriately used as a component material for insulated wires and wiring harnesses for automobiles, etc. In insulated wires and wiring harnesses, heat is easily generated by energizing the metal components represented by the wire conductors. For the polymer materials arranged near these metal components, high heat resistance is also required to prevent irreversible deformation when heated. On the other hand, when the cross-linked polymer composition is formed into a desired shape by heat forming such as extrusion molding, it is hoped that the cross-linked polymer composition has high fluidity and is in a state of excellent formability. In addition, depending on the requirements such as the deformation of the insulated wire and the change of the structure of the wiring harness, it is sometimes also required to reshape the polymer material that has been formed into a predetermined shape.

[0134] In insulated wires and wiring harnesses, the specific locations where the cross-linked polymer material according to the embodiments of the present disclosure is applied are not particularly limited. Examples include the insulating coating covering the outer periphery of the wire conductor of the insulated wire, the outer packaging material for bundling multiple insulated wires in a wiring harness, wire protective materials, and waterproof plugs for waterproofing connectors. Among these, the insulating coating of the insulated wire is preferably formed of the cross-linked polymer material according to the embodiments of the present disclosure.

[0135] exist Figure 2 ] An example of the insulated wire according to the embodiment of the present disclosure is shown in a cross section perpendicular to the axial direction. Figure 2 The insulated wire 1 shown includes a wire conductor 2 and an insulating coating 3 covering the outer periphery of the wire conductor 2. The structure of the wire conductor 2 is not particularly limited, but is formed in the form of a stranded conductor formed by twisting a plurality of single wires 21. In the example shown, the insulated wire 1 is formed in a form having a flat portion, and the cross-section of the wire conductor 2 is flat (elongated in the width direction). The insulating coating 3 is composed of the cross-linked polymer material according to the embodiment of the present disclosure described above. The insulating coating 3 also has a flat cross-sectional shape that follows the shape of the wire conductor 2.

[0136] In the insulated wire 1, heat is generated when current is passed through the wire conductor 2, and the insulating coating 3 is also heated. However, the insulating coating 3 is composed of the cross-linked polymer material according to the embodiment of the present disclosure described above and has high heat resistance. Therefore, if the temperature is at least below 190°C, even if the insulating coating 3 is heated, it is unlikely to suffer thermal effects such as irreversible deformation.

[0137] By having a flat portion, the insulated wire 1 can reduce the space required for configuration and improve space saving. Here, the cross-linked polymer material constituting the insulating coating 3 has re-formability, and the insulated wire 1 with a flat portion can be easily formed using a conventional insulated wire (round wire) with a roughly circular cross-section. For example, a round wire can be manufactured by extruding the cross-linked polymer composition according to the embodiment of the present disclosure after heat mixing onto the outer periphery of the wire conductor 2. At this time, if the extrusion molding is carried out at a temperature above the decomposition point or phase transition point of component A and above the melting point of component C, the extrusion molding can be smoothly carried out in a state where the cross-linked polymer composition has high heat deformability, and the insulating coating 3 is obtained in a state where a cross-linked body of components A and B is formed by extrusion molding. If the insulated wire is used without forming a flat portion, the round wire in this state can be directly used.

[0138] When forming a flat portion on an insulated wire, the flat portion can be easily formed by applying a compressive force in one direction to the round wire produced above while heating it to a temperature above the flow start temperature of the cross-linked body and above the melting point of the C component. This is because the wire conductor 2 is constructed in the form of a stranded conductor and is easily deformed by the application of force, and the insulating coating 3 is also rendered fluid by heating, thereby easily deforming in accordance with the deformation of the wire conductor 2. The insulating coating 3 can then be allowed to cool naturally, returning to its original stable cross-linked state. Alternatively, by applying a compressive force from both sides in the width direction to the already formed flat portion while heating the insulating coating 3 to a temperature above the flow start temperature of the cross-linked body and above the melting point of the C component, the flat portion can be restored to the shape of a round wire or a shape similar to it with a lower flatness. In this case, the insulating coating 3 also deforms in accordance with the deformation of the wire conductor 2, deforming into a shape with a lower flatness.

[0139] In this way, the insulating coating 3 is composed of a cross-linked polymer composition containing component C in addition to components A and B. While the cross-linked polymer composition has high heat deformability, the insulating coating 3 can be efficiently formed by extrusion onto the outer periphery of the wire conductor 2. Furthermore, since the insulating coating 3 is composed of a material with reversible reshapeability, the insulating coating 3 can be deformed to follow the deformation of the wire conductor 2, while the insulated wire 1 can be easily deformed into any desired shape, such as by bidirectionally deforming between a flat cross-section and a roughly circular cross-section. For example, within the configuration path, the cross-sectional shape of the insulated wire can be changed with a high degree of freedom, such as by forming a flat portion on a round wire, only in areas where space conservation is required. Thus, for example, a common wire can be used as a raw material to produce various insulated wires having flat portions in different locations. The insulated wire can be used alone, or it can be connected to components such as a connection terminal, or bundled with other insulated wires to be used in the form of a wire harness containing the insulated wires.

[0140] Example

[0141] The following examples are provided. The present invention is not limited to these examples. Unless otherwise specified, sample preparation and evaluation were performed at room temperature in the atmosphere.

[0142] <Sample Preparation>

[0143] In order to prepare samples A1 to A22 and samples B1 to B20, component A, component B and component C were kneaded in the formulations (parts by mass) described in Tables 1 and 2. For kneading, a kneading / extrusion tester ("Labo Plastomill" manufactured by Toyo Seiki Co., Ltd.) was used at 240°C and 50 rpm for 5 minutes. Then, a sample sheet with a thickness of 2 mm was produced by press molding at 240°C for 5 minutes. When used in each evaluation, a sample sheet that had been hot-pressed for more than 24 hours was used. At least in samples A1 to A22, crosslinking of component B caused by the metal ions from component A was induced by heating to 240°C during kneading and press molding. The progress of crosslinking was confirmed by infrared absorption spectroscopy. Specifically, the C=O stretching vibration (1790 cm-1) of the anhydride present in the infrared absorption spectrum of component B before crosslinking was confirmed. -1 near) and C=O stretching vibration of carboxylic acid (1720 cm -1 The absorption near the surface of the substrate disappears or decreases with cross-linking.

[0144] The materials used are as follows.

[0145] (1)A component

[0146] Hereinafter, the material type is shown, and the decomposition point or phase transition point obtained by DSC measurement is shown in parentheses.

[0147] ･Ca-AA: Calcium(II) acetylacetonate (110℃)

[0148] ･Zn-AA: Zinc(II) acetylacetonate (105℃)

[0149] ･Al-AA: Aluminum(III) acetylacetonate (112℃)

[0150] ･Zr-AA: Zirconium(IV) acetylacetonate (180℃)

[0151] ･ZnO: Zinc (II) oxide (None (>300℃))

[0152] ･stCa: Calcium stearate (93℃)

[0153] (2) Component B

[0154] The following summarizes the material types, flow start temperature (the measurement method is the same as that described in the evaluation method section below), and hardness (Shore D hardness measured in accordance with JIS K 6253).

[0155] MAH-SEBS: Maleic acid-modified hydrogenated styrene thermoplastic elastomer, "M1911" manufactured by Asahi Kasei Corporation, flow start temperature 142°C, D hardness 36

[0156] MAH-EO: Maleic acid-modified ethylene-α-olefin copolymer, "MH5020" manufactured by Mitsui Chemicals, flow start temperature 132°C, D hardness 15

[0157] MAH-EMA: Maleic acid-modified ethylene-methyl acrylate copolymer, "OREVAC 18603" manufactured by SK Functional Polymers, flow start temperature 83°C, D hardness 29

[0158] MAH-EVA: Maleic acid-modified ethylene-vinyl acetate copolymer, "OREVAC 18211" manufactured by SK Functional Polymers, flow start temperature 42°C, D hardness 10

[0159] MAH-LLDPE: Maleic acid-modified low-density polyethylene, "OREVAC18302N" manufactured by SK Functional Polymers, flow start temperature 95°C, D hardness 18

[0160] MAH-PP: Maleic acid-modified polypropylene, "ADMER QB550" manufactured by Mitsui Chemicals, flow start temperature 142°C, D hardness 58

[0161] AA-PP: Acrylic-modified polypropylene, "POLYBOND 1001" manufactured by Chemtura, flow start temperature 139°C, D hardness 45

[0162] EMAA: Ethylene methacrylic acid copolymer, "N1110H" manufactured by Mitsui-Dow Polychemicals, flow start temperature 109°C, D hardness 49

[0163] SEBS: Hydrogenated styrene-based thermoplastic elastomer, "H1041" manufactured by Asahi Kasei Corporation, flow start temperature 137°C, D hardness 36

[0164] (3) Component C

[0165] The types of materials are shown below. The melting points of the materials are shown in Tables 1 and 2. stA, ERA, and EBSA were manufactured by Tokyo Chemical Industry Co., Ltd., and the others were manufactured by Nitto Chemical Industry Co., Ltd.

[0166] ･stNa: Sodium stearate

[0167] ･stLi: lithium stearate

[0168] ･stBa: Barium stearate

[0169] ･HstNa: Sodium 12-hydroxystearate

[0170] ･HstLi: 12-Hydroxystearate lithium

[0171] ･BeNa: Sodium behenate

[0172] ･BeLi: Lithium behenate

[0173] ･MoNa: Sodium montanate

[0174] ･MoLi: Lithium montanate

[0175] ･stCa: Calcium stearate

[0176] ･stZn: Zinc stearate

[0177] ･HstCa: 12-hydroxystearate calcium

[0178] ･MoCa: Calcium montanate

[0179] ･LaLi: Lithium laurate

[0180] ･stA: Stearic acid

[0181] ･ERA: Erucamide

[0182] ･EBSA: Ethylene bisstearamide

[0183] Evaluation Method

[0184] (1) Flow start temperature

[0185] A 10 mm x 10 mm x 2 mm test piece was prepared using the above sample. This test piece was placed on a temperature-variable hot plate. A 2 mm diameter cylindrical indenter with a graduated scale on top was pressed into the center of the test piece with a force of 1 N. The hot plate temperature was then raised at a rate of 5°C / minute, and the distance the indenter penetrated the sample piece was recorded.

[0186] The temperature at which the indenter penetrated 2.0 mm (penetrated the sample) was defined as the flow initiation temperature. It is believed that samples with a flow initiation temperature 5°C or higher than that of component B without components A and C have undergone crosslinking due to metal ions, resulting in improved heat resistance.

[0187] (2) Elastic modulus

[0188] The sample was cut into strips measuring 50 mm in length, 5 mm in width, and 2 mm in thickness. A tensile test was performed at room temperature in air, with a clamping width of 10 mm and a speed of 10 mm / min. The elastic modulus (tensile modulus) was then calculated by converting the strain under a tensile load between 1 N and 2 N.

[0189] (3) Heating deformation rate

[0190] A 10 mm x 10 mm x 2 mm test piece was prepared from the sample sheet. This test piece was fixed to the side of a 10 mm diameter stainless steel round bar to create a test body. A 0.7 mm thick metallic blade was pressed against the surface of the test body. The load F (N) applied to the blade was determined using the following formula.

[0191] F=0.7[i(2D-i)] 1 / 2

[0192] Here, i is the thickness of the sample piece, which is 2 (mm). D represents the outer diameter of the test body, which is 14 (mm) as 10 (mm) + 2i. It should be noted that the load setting based on the above formula is determined with reference to the setting method used in JIS C 3660-508.

[0193] The sample pressed by the blade as described above was heated in an oven at 170°C or 210°C for 4 hours. The blade was then removed, cooled to room temperature, and the depth of the resulting dent was measured using a laser microscope. The ratio of the dent depth to the thickness of the sample sheet used (2 mm) was taken as the deformation rate (%), the deformation rate at 170°C was taken as the "170°C deformation rate", and the deformation rate at 210°C was taken as the "210°C deformation rate". In addition, the deformation rate at 210°C relative to the deformation rate at 170°C was taken as the "deformation rate ratio" (210°C deformation rate / 170°C deformation rate). The larger the deformation rate ratio, the greater the difference in heat deformation properties below 190°C and above 190°C, indicating that a high effect can be obtained in maintaining heat resistance below 190°C and improving forming efficiency above 190°C. If the deformation rate ratio is 5 or more, it can be said that these effects are sufficiently high.

[0194] (4) Film appearance

[0195] The surfaces of the sample pieces were visually observed and evaluated for appearance. Sample pieces with a smooth, uniform surface were rated as having an excellent appearance (A+), while samples with a smooth surface but slight color unevenness were rated as having a good appearance (A). On the other hand, samples with noticeable aggregates or incompatible materials observed in color or smoothness, or with surface unevenness, were rated as having a poor appearance (B).

[0196] (5) State changes accompanying kneading of the composition

[0197] Using infrared absorption spectroscopy, the contribution of component C was verified by the changes in the cross-linked polymer composition accompanying kneading. Here, a composition containing 5 parts by mass of Ca-AA as component A, 95 parts by mass of MAH-SEBS as component B, and 5 parts by mass of stLi as component C was prepared. Measurement samples were prepared by kneading the composition at 240°C for 1 minute, 3 minutes, and 5 minutes, and the infrared absorption spectrum of each measurement sample was measured. The infrared absorption spectrum was also measured for a reference sample containing 5 parts by mass of Ca-AA as component A, 95 parts by mass of MAH-SEBS as component B, and no component C. The spectrum of the reference sample was subtracted from the spectrum of each of the above-mentioned measurement samples to obtain a difference spectrum. The difference spectrum corresponds to the spectrum in which the contribution of component C was extracted from each measurement sample.

[0198] <Evaluation Results>

[0199] In the following Tables 1 and 2, for samples A1 to A22 and B1 to B20, the content of each component (unit: parts by mass) is shown in the upper row, and the results of each evaluation are shown in the lower row.

[0200] [Table 1]

[0201]

[0202] [Table 2]

[0203]

[0204] As shown in Table 1, Samples A1 to A22 all contain a component A that releases metal ions upon heat, a component B composed of an organic polymer containing electron-withdrawing substituents in its side chains capable of forming ionic bonds with metal ions, and a component C having the structure of Formula (1) and a melting point of 190°C or higher. The resulting sample sheets, crosslinked during kneading and press molding, all have a flow start temperature of 190°C or higher. The flow start temperatures of Samples A1 to A22 are each 5°C or higher higher than the flow start temperature of Component B, indicating that crosslinking has resulted in high heat resistance. Furthermore, while the molding temperature of a typical thermoplastic resin is approximately 300°C, Samples A1 to A22 have a flow start temperature below 300°C, indicating high reformability. Furthermore, Samples A1 to A22 all have a deformation rate of 90% or higher at 210°C and a deformation rate of 10% or lower at 170°C, with a deformation rate ratio of 10 or higher. This indicates that both heat resistance at temperatures below 190°C and molding efficiency at temperatures above 190°C are maintained. The appearance of the sample was also good (A or A+), and a uniform material was obtained without the formation of aggregates or separation of insoluble substances.

[0205] Samples A1 to A4 differed in the type of metal contained in component A, and samples A1, A5 to A10 differed in the type of component B. Furthermore, samples A1, A11 to A18 differed in the structure of component C. In all cases, a high flow start temperature, a low elastic modulus, a high 210°C deformation rate, and a high deformation rate ratio were achieved. However, among the samples with different component B, samples A9 and A10 exhibited a higher elastic modulus than the other samples, corresponding to the case of using a modified resin based on polypropylene. Comparing samples A1 and A11, in which the metal contained in component C was monovalent Na or Li, with sample A12, in which the metal contained in component C was divalent Ba, samples A1 and A11 exhibited slightly lower elastic moduli and a higher 210°C deformation rate than sample A12. This is believed to be because the metal in component C is monovalent, making it difficult for component C to produce interactions that reinforce crosslinking between polymer chains in component B in a crosslinked product. The content of component C varied between samples A1, A19, and A20, and between samples A11, A21, and A22. However, compared to samples A20 and A22, which had a high content of 25.0 parts by mass of component C, samples A1, A19, A11, and A21, which had relatively low contents of 1.0 or 5.0 parts by mass of component C, showed better results in the appearance test. This is believed to be because the content of component C was kept low, making it less likely for component C to aggregate.

[0206] Unlike Samples A1 to A22, Samples B1 and B2 do not contain Component A. Crosslinking of Component B by metal ions does not proceed, resulting in a flow start temperature below 190°C. Furthermore, the deformation rate at 170°C is 100%, indicating plastic deformation. As such, Samples B1 and B2 exhibit low heat resistance.

[0207] In samples B3 and B4, zinc oxide and calcium stearate were used as component A instead of metal complexes. These compounds do not free metal ions even when heated, and therefore cannot crosslink component B. Correspondingly, in samples B3 and B4, the flow start temperature was significantly lower than 190°C, with almost no change from sample B1. In addition, the deformation rate at 170°C was 100%, which can be said to have caused plastic deformation. As such, the heat resistance of samples B3 and B4 is also low. It should be noted that calcium stearate can also be classified as component C.

[0208] In sample B5, EMAA is used as component B, and a carboxylic acid group as an electron-withdrawing group is present in the main chain of the polymer, but no electron-withdrawing substituent is present in the side chain. In the carboxylic acid group in the main chain, a cross-linked structure via an ionic bond with a metal ion cannot be effectively formed due to the steric hindrance of the adjacent methacryloyl group. Correspondingly, the flow start temperature is significantly lower than 190°C. In addition, in sample B5, a large value of elastic modulus exceeding 200 MPa is obtained. It is believed that this is because the cross-linked structure is formed on the main chain of component B, and the freedom of movement of the cross-linked site is reduced. In addition, in this sample B5, the deformation rate at 170°C is also 100%, which can be said to have caused plastic deformation. It is believed that this is because the cross-linking density is low and the heat resistance of the cross-linked body is not sufficiently improved.

[0209] In Sample B6, SEBS, component B, lacks a substituent capable of forming ionic bonds with metal ions, preventing the metal ions from component A from forming a crosslinked structure in component B. Consequently, the flow initiation temperature falls below 190°C. Furthermore, the heat resistance enhancement effect of crosslinking is not achieved, with a deformation rate of 100% at 170°C.

[0210] In samples B7 and B8, the raw materials contain component A, which releases metal ions by heat, and component B, which is composed of an organic polymer containing electron-withdrawing substituents in its side chains that can form ionic bonds with metal ions. This results in a crosslinked body in which component B is crosslinked using the metal ions released from component A by heating. Accordingly, the flow initiation temperature is significantly higher than 190°C. The deformation rate at 170°C is also suppressed to below 10%, indicating that high heat resistance is achieved through crosslinking. However, since samples B7 and B8 do not contain component C, the effect of improving the fluidity of the crosslinked body brought about by component C is not achieved, and the deformation rate at 210°C is significantly lower than 50%. The deformation rate ratio is also a small value of less than 5. Therefore, in samples B7 and B8, the efficiency of heat forming is reduced. It is believed that the sheet body was press-formed as heat forming, but in the case of extrusion forming, the extrusion speed cannot be increased due to low fluidity, resulting in reduced extrusion efficiency. Samples A1, A11 to A22 are samples in which component C is added to sample B7, and sample A5 is a sample in which component C is added to sample B8. However, both the 210°C deformation rate and the deformation rate ratio are greatly improved. From the comparison with samples B7 and B8, it is confirmed that the addition of component C has a high effect on improving the heat deformation property.

[0211] In samples B9 to B12, a component having a structure of formula (1) but a melting point below 190°C was added as component C. By adding component C, the 210°C deformation rate was significantly improved compared to sample B7, which did not contain component C, and the effect of improving the heat deformation property brought about by component C was achieved. However, due to the low melting point of component C, the heat deformation property was improved even below 190°C, and the 170°C deformation property achieved the same value (100%) as the 210°C deformation property. The flow start temperature was also below 190°C. As such, the desired heat resistance could not be achieved.

[0212] In sample B13, lauric acid in which m+n=9 in formula (1) is used as component C. By containing component C, the effect of improving heat deformability is obtained, and a small 170°C deformation rate of less than 10% and a large deformation rate ratio of more than 10 are obtained. However, the result of the appearance evaluation deteriorates (B). It is believed that since the alkyl chain of component C is short, the compatibility of the crosslinked body formed by components A and B with component C becomes low, and the surface of the sheet becomes uneven. It is believed that when extrusion molding is performed instead of press molding, the influence of low compatibility becomes further increased, and the appearance deteriorates.

[0213] In sample B14, stearic acid is used as component C, which is a molecule in which a hydrogen atom (H) is introduced instead of the metal M of formula (1). By adding stearic acid, as in the above-mentioned B9 to B12 in which a low-melting-point component C is added, the deformation rate at 170°C and the deformation rate at 210°C are greatly increased, the flow start temperature is reduced, and the heat resistance is reduced compared to sample B7 without component C. This is believed to be due to the low melting point of component C at 70°C. It is believed that the reason why stearic acid shows the effect of improving heat deformability is different from the case of the structure of formula (1) containing metal M, and is not due to the formation of an anion field, but simply because it acts as a solvent. In addition, in this sample B14, the result of the appearance evaluation deteriorates (B). It is believed that this is because the carboxyl group of stearic acid reacts with a part of component A, separates from component B, and forms an uneven structure.

[0214] In samples B15 to B18, molecules with an amide group introduced instead of the metal M of formula (1) were used as component C. The melting points were all below 150°C, and they melted at the mixing and forming temperatures. However, even when melted, an anion field was not formed, so the deformation rate at 210°C was a low value of less than 50%. The deformation rate ratio was also less than 5. In particular, in samples B17 and B18, the amount of the amide group-containing molecule added was increased compared to sample B16, but the increase in the 210°C deformation rate was extremely small. In other words, if it is not a molecule that forms an anion field, even if the amount added is increased, the heat deformability cannot be improved.

[0215] In samples B19 and B20, since the crosslinkable polymer composition does not contain component A, a crosslinking reaction of component B does not occur, and the flow initiation temperature does not show a significant increase compared to the case of component B alone (sample B1). Although component C is added, component C does not liberate metal ions even when heated, and therefore does not replace component A to cause metal crosslinking of component B. The same is true for sample B4, which uses calcium stearate, which is equivalent to component C, as component A. In sample B20, since component C has a hydroxyl group, it is possible that component C interacts with component B to form a bond such as an ester bond, but it is believed that the reactivity of such bond formation is low, and the effect of reducing the fluidity of component B through crosslinking is very low.

[0216] Finally, the results of confirming the state change caused by kneading of the composition using infrared absorption spectroscopy are shown in FIG. Figure 3 In. Figure 3 The figure shows the difference spectra obtained by subtracting the spectrum of a reference sample containing no C from the spectrum of the sample kneaded at 240°C for 1 minute, 3 minutes, and 5 minutes, respectively. The spectrum of component C alone is also shown in the uppermost dashed line. As described above, the difference spectra correspond to the spectra obtained by extracting the contribution of component C from each sample.

[0217] When observing the difference spectrum of each measurement sample, when the kneading time is 1 minute, it is similar to the spectrum of only C component (dashed line), but when the kneading time is prolonged, the 1580cm -1 and 1560cm -1 The absorption peaks at 1450 cm -1 and 1400cm -1 The absorption peak gradually changes to 1660 cm-1 corresponding to the anionized state. -1 ~1600cm -1 and 1490cm -1 ~1360cm -1 This change indicates that the carboxylic acid constituting the metal salt in component C forms an anion field, which is delocalized by heating and kneading to form a wide range of anion fields.

[0218] As mentioned above, although embodiment of this disclosure was demonstrated in detail, this invention is not limited at all to the said embodiment, Various changes are possible within the range which does not deviate from the summary of this invention.

[0219] Explanation of symbols

[0220] 1 Insulated wire

[0221] 2 Wire conductors

[0222] 21 single line

[0223] 3 Insulation coating

Claims

1. A cross-linkable polymer composition, wherein The cross-linkable polymer composition comprises: A component, wherein the metal ions of the component are released by heat; A component B, wherein the component B is composed of an organic polymer having a side chain and containing an electron-withdrawing substituent capable of forming an ionic bond with the metal ion released from the component A; and Component C, which is composed of a compound having a structure represented by the following formula (1) and a melting point of 190° C. or higher, The crosslinked product obtained by crosslinking the component B with the metal ions released from the component A has a flow starting temperature of 190° C. or higher. Here, R represents a hydrogen atom or a hydroxyl group, m and n are each an integer greater than or equal to 1, m+n is greater than or equal to 11 and less than or equal to 30, and M y+ It represents a metal ion with a valence of y, where y is an integer greater than or equal to 1, and x=y.

2. The cross-linkable polymer composition according to claim 1, wherein The melting point of the component C and the flow starting temperature of the crosslinked body are 300° C. or lower.

3. The cross-linkable polymer composition according to claim 1, wherein The component A has a decomposition point or a phase transition point at a temperature not higher than the melting point of the component C.

4. The cross-linkable polymer composition according to claim 1, wherein The component A has a decomposition point or a phase transition point at 50° C. or higher and 300° C. or lower.

5. The cross-linkable polymer composition according to claim 1, wherein In the C component, x=y=1.

6. The cross-linkable polymer composition according to claim 1, wherein The component B has a flow start temperature within a range of 50° C. to 190° C.

7. The cross-linkable polymer composition according to claim 1, wherein The component A has a decomposition point or a phase transition point at a temperature equal to or higher than the flow start temperature of the component B.

8. The cross-linkable polymer composition according to claim 1, wherein The component A is a metal complex containing a ligand having the structure of the following formula (2): Here, R1 and R2 each independently represent a hydrocarbon group having 1 to 8 carbon atoms, and R3 represents a hydrogen atom or a hydrocarbon group having 1 to 8 carbon atoms, including a case where at least two of R1, R2 and R3 are connected to each other via a ring structure.

9. The cross-linkable polymer composition according to claim 1, wherein The metal ions released from the component A are ions of at least one of alkaline earth metals, aluminum, zinc, titanium, and zirconium.

10. The cross-linkable polymer composition according to claim 1, wherein The substituent of the component B is at least one of a carboxylic acid group, an acid anhydride group, a phosphoric acid group, and an acrylic acid group.

11. The cross-linkable polymer composition according to claim 1, wherein The substituent of the component B is bonded to the main chain via an alkyl group or an alkylene group having 1 or more carbon atoms.

12. The cross-linkable polymer composition according to claim 1, wherein The B component does not contain electron withdrawing groups in the main chain.

13. The cross-linkable polymer composition according to claim 1, wherein The crosslinkable polymer composition contains 0.1 parts by mass or more and 30 parts by mass or less of the component A, assuming that the total amount of the component A, the component B, and the component C is 100 parts by mass.

14. The cross-linkable polymer composition according to claim 1, wherein The total amount of the component A, the component B, and the component C is set to 100 parts by mass, and the crosslinkable polymer composition contains 1.0 part by mass or more and 30 parts by mass or less of the component C.

15. A cross-linked polymer material, wherein: The cross-linked polymer material is formed by cross-linking the cross-linkable polymer composition according to any one of claims 1 to 14. The cross-linked polymer material includes the component C and a cross-linked product obtained by cross-linking the component B with metal ions released from the component A.

16. An insulated wire, wherein: The insulated wire has a wire conductor and an insulating coating. The insulating coating layer is made of the cross-linked polymer material according to claim 15 and covers the outer periphery of the electric wire conductor.

17. The insulated wire according to claim 16, wherein The wire conductor is formed by twisting multiple single wires. The insulated wire has a flat portion in which a cross section of the wire conductor perpendicular to the axial direction is flat.

18. A wiring harness, wherein: The wiring harness includes the insulated electric wire according to claim 16.

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