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

Abstract

Provided are: a crosslinkable polymer composition which is capable of being crosslinked by heating and which obtains a crosslinked body having high heat resistance and wear resistance; a crosslinked polymer material which is capable of being crosslinked by heating and which has high heat resistance and wear resistance; and an insulated wire and a wire harness which are provided with such a crosslinked polymer material. The crosslinkable polymer composition includes: 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 comprising a secondary amine or a tertiary amine represented by formula (1). Here, R1 is a hydrogen atom or a hydrocarbon group having 30 or less carbon atoms, R2 is a hydrocarbon group having 30 or less carbon atoms, and R3 is a hydrocarbon group having 13-30 carbon atoms. # imgabs0 #

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] As in patent document 3, by utilizing the ionic bond between the substituent of an organic polymer and a metal ion, a polymer material that can be cross-linked and excellent in heat resistance can be obtained. On the other hand, in polymer materials, in addition to heat resistance, mechanical strength such as wear resistance is also mostly required. For example, in insulated wires and wiring harnesses, when it is envisioned that there will be contact between other components such as equipment present in the periphery and between adjacent wires, it is desirable that the insulating coating has high wear resistance from the viewpoint that it is not easy to be damaged by these contacts. As one of the methods for improving wear resistance in cross-linked polymer materials, improving the degree of crosslinking can be cited. However, according to the inventor's research, as in patent document 3, when using a method for forming crosslinks by the ionic bond between the substituent of an organic polymer and a metal ion, it is sometimes difficult to obtain high wear resistance. In particular, when using an organic polymer with high flexibility as component B, it is difficult to obtain high wear resistance.

[0013] In view of the above, an object is to provide a cross-linkable polymer composition that can be cross-linked by heating to obtain a cross-linked body having high heat resistance and wear resistance, a cross-linked polymer material that can be cross-linked by heating and has high heat resistance and wear resistance, and an insulated wire and wiring harness comprising such a cross-linked polymer material.

[0014] Means for solving problems

[0015] The cross-linkable polymer composition involved in the present disclosure comprises: component A, which releases metal ions by heat; 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 component A; and component C, which is composed of a secondary amine or tertiary amine represented by the following formula (1).

[0016]

[0017] Here, R1 is a hydrogen atom or a hydrocarbon group having 30 or less carbon atoms, R2 is a hydrocarbon group having 30 or less carbon atoms, and R3 is a hydrocarbon group having 13 or more and 30 or less carbon atoms.

[0018] 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.

[0019] 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.

[0020] The present disclosure relates to a wiring harness including the insulated electric wires.

[0021] Effects of the Invention

[0022] The crosslinkable polymer composition disclosed herein is capable of forming crosslinks upon heating, yielding a crosslinked product having high heat resistance and wear resistance. The crosslinked polymer material disclosed herein is capable of forming crosslinks upon heating, exhibiting high heat resistance and wear resistance. 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

[0023] [ 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.

[0024] [ Figure 2 ] Figure 2It is a cross-sectional view showing the structure of an insulated wire according to one embodiment of the present disclosure. DETAILED DESCRIPTION

[0025] [Description of Embodiments of the Present Disclosure]

[0026] 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.

[0027] [1] The crosslinkable polymer composition of the present disclosure comprises: a component A, wherein the component A releases metal ions by heat; a component B, wherein the component B is composed of an organic polymer having a side chain and wherein the side chain contains an electron-withdrawing substituent capable of forming an ionic bond with the metal ions released from the component A; and a component C, wherein the component C is composed of a secondary amine or a tertiary amine represented by the following formula (1).

[0028]

[0029] Here, R1 is a hydrogen atom or a hydrocarbon group having 30 or less carbon atoms, R2 is a hydrocarbon group having 30 or less carbon atoms, and R3 is a hydrocarbon group having 13 or more and 30 or less carbon atoms.

[0030] The crosslinkable polymer composition disclosed herein can crosslink component B via the metal ions released from component A by heating. Therefore, while the uncrosslinked composition can achieve high processability, by heating it to form a crosslinked structure, a polymer material with high heat resistance can be easily obtained. Furthermore, since the crosslinked structure in the crosslinkable polymer composition disclosed herein is formed by ionic bonds, it is less likely to experience a decrease in flexibility due to crosslinking compared to a crosslinked structure formed by covalent bonds. Therefore, the polymer material is less likely to become hardened by crosslinking. For example, even when forming the insulation coating of a large-diameter electric wire, the flexibility of the insulation coating is less likely to decrease when bent. Furthermore, in a crosslinked structure formed from the crosslinkable polymer composition disclosed herein, the reversibility of the ionic bonds can be exploited by heating to reshape the crosslinked polymer material. This is because reheating the already formed crosslinked structure causes the crosslinking points caused by the ionic bonds to shift, causing the material to fluidize.

[0031] Furthermore, the crosslinkable polymer composition according to the present disclosure contains a component C composed of a secondary or tertiary amine having the structure of the above formula (1), thereby increasing the degree of crosslinking and achieving high wear resistance compared to a composition without the component C. This is believed to be because the amine in the component C becomes cationized and bonds with the electron-withdrawing substituent in the side chain of the component B, thereby suppressing the rate of crosslinking of the component B by the component A, and allowing crosslinking to proceed uniformly throughout the entire material.

[0032] [2] In the embodiment of [1] above, the cross-linked body may have a flow start temperature of 190°C or higher and 300°C or lower. By setting the flow start temperature of the cross-linked body to 190°C or higher, the cross-linked polymer material does not flow at temperatures below 190°C, and thus has particularly high heat resistance. A heat-resistant material having a flow start temperature of 190°C or higher is particularly suitable for use in insulating coatings for automotive electrical wires. On the other hand, by suppressing the flow start temperature of the cross-linked body to 300°C or lower, reshaping properties achieved by heating at temperatures below 300°C are ensured.

[0033] [3] In the embodiment of [1] or [2] above, in the formula (1), when R1 is a hydrocarbon group, the hydrocarbon group and the hydrocarbon groups of R2 and R3 may each independently be a linear alkyl group or an aromatic ring group. This reduces steric hindrance near the nitrogen atom of component C, and can effectively suppress the crosslinking of component B caused by metal ions released from component A.

[0034] [4] In any of the above aspects [1] to [3], 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 derived from the component A. Furthermore, when the uncrosslinked crosslinkable polymer composition is formed into a desired shape by extrusion or the like, high moldability can be achieved.

[0035] [5] In any of the above aspects [1] to [4], 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. On the other hand, at an appropriate temperature, the component A decomposes or undergoes a phase transition, and the metal ions are easily released from the component A. Therefore, the crosslinking reaction can proceed at a temperature that does not cause deterioration of the component B.

[0036] [6] In any of the above-mentioned embodiments [1] to [5], the component A may have a decomposition point or a phase transition point at a temperature higher than the flow start temperature of the component B. Thus, when the component B has already acquired fluidity, the metal ions are released from the component A and the 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 body with high spatial uniformity of cross-linking points can be obtained. Thus, combined with the effect brought about by the contribution of the component C, a high effect can be obtained in improving the wear resistance of the cross-linked polymer material. In addition, in the preparation of the cross-linkable polymer composition, the metal ions are not easily released from the component A and the cross-linking of the component B occurs unintentionally.

[0037] [7] In any one of the above aspects [1] to [6], the component A may be a metal complex containing a ligand having a structure represented by the following formula (2).

[0038]

[0039] Here, R4 and R5 each independently represent a hydrocarbon group having 1 to 8 carbon atoms, and R6 represents a hydrogen atom or a hydrocarbon group having 1 to 8 carbon atoms. This also includes the case where at least two of R4, R5, and R6 are linked to each other via a ring structure.

[0040] 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.

[0041] [8] In any of the above embodiments [1] to [7], 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.

[0042] [9] In any of the above embodiments [1] to [8], the substituent of 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 readily form ionic bonds with the metal ions released from component A. Furthermore, since these substituents are acidic groups with relatively low polarity, they are less likely to cause phase separation in the main chain and side chains of component B, allowing for the formation of a cross-linked structure with high spatial uniformity. This, combined with the effect of component C, can achieve a high effect in improving the wear resistance of the cross-linked polymer material.

[0043]

[10] In any of the above aspects [1] to [9], 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 movement, and facilitates the movement of the crosslinking point during heating, thereby achieving particularly high reshaping properties.

[0044]

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

[10] , the component B may have a glass transition temperature of 10°C or lower. This allows the crosslinked polymer material obtained through the crosslinking reaction to easily achieve both high mechanical strength, such as high abrasion resistance, and high flexibility. A polymer material having excellent mechanical strength and flexibility can be suitably used, for example, to form an insulating coating layer of an insulated wire. The glass transition temperature of the component B is more preferably 0°C or lower.

[0045]

[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, competition with the electron-withdrawing groups in the main chain does not hinder the formation of ionic bonds between the substituents in the side chains and the metal ions from the component A. The substituents in the main chain have difficulty forming a stable cross-linked structure between the substituents in the main chain and the metal ions due to steric hindrance. Furthermore, even if a cross-linked structure is formed, the freedom of movement of the cross-linked sites is reduced, making it difficult to obtain high reshaping properties in the cross-linked product.

[0046]

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

[12] , the main chain of the component B may be an olefin polymer or a styrene polymer. Thus, the high mechanical strength provided by these main chains is easily exhibited as a characteristic of the crosslinked product. Furthermore, the main chain is less likely to affect the formation and movement of crosslinking points on the side chains of the component B, and the high heat resistance, wear resistance, and reshaping properties provided by these phenomena on the side chains are effectively exhibited as characteristics of the material as a whole.

[0047]

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

[13] , 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.

[0048]

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

[14] , 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 0.5 parts by mass or more and 20 parts by mass or less of the component C. Thus, by containing a sufficient amount of the component C, a high effect can be achieved in terms of improving the uniformity of the crosslinked sites in the crosslinked product and thereby improving the wear resistance. On the other hand, by not containing an excessive amount of the component C, the crosslinked material is less likely to have a decrease in physical properties such as material strength and low-temperature characteristics, or an excessive increase in elastic modulus, due to the formation of aggregates from the component C or insufficient content of the component B.

[0049]

[16] 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

[15] 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, so that the cross-linked polymer material has both high heat resistance and reshapeability due to heating. In addition, the reduction in flexibility caused by cross-linking is not likely to occur. In the cross-linked polymer material, most of the component C does not enter the cross-linked structure, but due to the contribution of the component C, the cross-linked structure is formed with high uniformity throughout the cross-linked polymer material, and the cross-linked polymer material has high wear resistance.

[0050]

[17] In the embodiment of

[16] above, the cross-linked polymer material may have a tensile modulus of less than 20 MPa. Thus, the cross-linked polymer material has high flexibility. However, a cross-linked polymer material having a tensile modulus of greater than 20 MPa is also preferred in terms of excellent mechanical strength such as wear resistance.

[0051]

[18] 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

[16] or

[17] and covers the outer periphery of the wire conductor. In the insulated wire, the insulating coating is composed of the cross-linked polymer material involved in 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 can also easily follow the shape of the wire conductor and deform. In addition, since the cross-linked polymer material contains a C component, the uniformity of the cross-linked portion brought about by the C component is improved, and high wear resistance can be obtained in the insulating coating formed by heat forming such as extrusion molding and the insulating coating in the state of being reshaped 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.

[0052]

[19] In the embodiment of

[18] 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 viewpoint 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, deformation between a state with a low degree of flatness such as a circular cross section and a flat state can be easily performed 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.

[0053]

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

[18] or

[19] above. As described above, the insulated wire of the present disclosure has excellent heat resistance, formability during initial forming and re-forming, and abrasion resistance, and these properties can be utilized even in a wiring harness.

[0054] [Details of embodiments of the present disclosure]

[0055] 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.

[0056] [1] Cross-linkable polymer composition and cross-linked polymer material

[0057] The crosslinkable polymer composition according to an 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 secondary or tertiary amine represented by the following formula (1).

[0058]

[0059] Here, R1 is a hydrogen atom or a hydrocarbon group having 30 or less carbon atoms, R2 is a hydrocarbon group having 30 or less carbon atoms, and R3 is a hydrocarbon group having 13 or more and 30 or less carbon atoms.

[0060] The crosslinkable polymer composition according to this embodiment forms a crosslinked product obtained by crosslinking component B with metal ions released from component A upon heating, thereby constituting a crosslinked polymer material according to an embodiment of the present disclosure. The crosslinked polymer material comprises this crosslinked product and component C. It should be noted that, in this specification, the crosslinkable polymer composition generally refers to a state in which a crosslinked product has not yet been formed, but materials that undergo a certain degree of crosslinking during heat forming such as heat kneading or extrusion are also included in the crosslinkable polymer composition.

[0061] (1) Characteristics of cross-linkable polymer compositions and cross-linked polymer materials

[0062] Before describing in detail the various components that constitute the cross-linkable polymer composition, the characteristics of the cross-linkable polymer composition and the cross-linked polymer material will be described first. The cross-linkable polymer composition involved in this embodiment comprises: component A, which releases metal ions by heat; component B, which has a substituent capable of forming an ionic bond with the metal ion; and component C, which is a secondary amine or tertiary amine having a structure represented by formula (1). When the cross-linkable 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 cross-linked via the ionic bonds. On the other hand, in the cross-linked polymer material, most of 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).

[0063] 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 the formation of ionic bonds 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 molding 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, the crosslinked product can be formed into the desired shape by extrusion molding or the like after or while the crosslinked product is formed by heating.

[0064] Crosslinking improves heat resistance compared to the pre-crosslinked state by crosslinking adjacent polymer chains of component B. In the crosslinked product, the organic polymer chains of component B are crosslinked via ionic bonds, whose bonding force is stronger than van der Waals forces, effectively improving the heat resistance and mechanical toughness of the crosslinked product. 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.

[0065] 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.

[0066] 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 1As 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.

[0067] 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.

[0068] As described above, the crosslinkable polymer composition according to this embodiment comprises a component A that releases metal ions upon heat, and a component B having a substituent in its side chain capable of forming an ionic bond with the metal ion. Upon heating, the composition provides a crosslinked polymer material having high heat resistance and reshaping properties. Due to these properties, the crosslinked polymer material according to this embodiment can be suitably used in components that require high heat resistance and benefit from reshaping properties, such as the insulation coating of insulated wires. In a crosslinked polymer material, as an indicator of sufficient heat resistance improvement due to crosslinking, the crosslinked polymer material preferably has a flow start temperature that is at least 5°C higher, and further at least 10°C higher, than the flow start temperature of component B alone.

[0069] As described above, in the crosslinkable polymer composition according to this embodiment, components A and B form an ionically bonded crosslinked structure, resulting in a crosslinked polymer material having high heat resistance and reshapeability, and being less susceptible to a decrease in flexibility due to crosslinking. Furthermore, since the crosslinkable polymer composition contains component C in addition to components A and B, the crosslinked polymer material obtained by crosslinking exhibits further excellent mechanical strength, such as wear resistance. The reasons for this are as follows.

[0070] When a crosslinkable polymer composition does not contain component C, a crosslinking reaction caused by the formation of ionic bonds between the metal ions released from component A and the substituents of component B sometimes occurs rapidly. Thus, the crosslinking reaction may proceed locally, forming aggregates. In this case, the crosslinking reaction does not occur uniformly throughout the entire material, and the degree of crosslinking of the material as a whole is difficult to improve. The crosslinked structure between polymer chains acts as a structure that improves the mechanical strength, such as the wear resistance, of the polymer material. However, when the crosslinked structure cannot be uniformly formed throughout the entire material as described above, and the degree of crosslinking is low as a whole, the mechanical strength improvement effect brought about by the crosslinked structure cannot be fully obtained in the crosslinked polymer material, and the wear resistance cannot be fully improved.

[0071] On the other hand, when a component C composed of a secondary amine or a tertiary amine is contained in a crosslinkable polymer composition, at least a portion of the component C becomes a secondary ammonium cation or a tertiary ammonium cation when heated. The generated ammonium cation forms an ionic bond between the ammonium cation and the electron-withdrawing substituent of the side chain of the component B. The formation of the ionic bond between the ammonium cation and the substituent of the component B competes with the reaction of forming an ionic bond between the metal ion released from the component A and the substituent of the component B to form a crosslink, at least partially hindering the crosslinking reaction between the polymer chains of the component B via the metal ion. As a result, the rate of progress of the crosslinking reaction is reduced. The reduction in the rate of progress of the crosslinking reaction can be confirmed, for example, by the fact that the exothermic peak corresponding to the progress of the crosslinking reaction in differential scanning calorimetry (DSC) becomes gentle due to the addition of the component C.

[0072] Like this, when the speed of the cross-linking reaction of the polymer chain of component B caused by the metal from component A is suppressed, it is not easy to occur that the cross-linking reaction is carried out locally quickly and forms aggregates as when component C is not added. Thus, the cross-linking reaction is carried out uniformly and highly in the entire material, and the degree of cross-linking also increases. In addition, since the progress of the cross-linking reaction slows down, it is also difficult to cause a sharp increase in viscosity caused by cross-linking, so the heating and kneading of the material can be carried out for a long time. This also contributes to the rising of the degree of cross-linking. By improving the uniformity and degree of cross-linking of the cross-linking reaction, the resulting cross-linked polymer material distributes the cross-linked structure uniformly and highly in space, and has a cross-linked structure with high density. Thus, the cross-linked polymer material becomes a material with excellent mechanical strength represented by wear resistance.

[0073] An increase in crosslink density can be evaluated as an increase in the gel fraction of the crosslinked polymer material. For example, the gel fraction of the crosslinked polymer material can be 80% or higher, and further can be 85% or higher. The upper limit of the gel fraction is not particularly specified, but is generally 95% or lower. As described in the examples below, the gel fraction can be evaluated by immersing the polymer material in a solvent such as xylene, extracting the non-crosslinked components, and then calculating the ratio of the mass after immersion to the mass before immersion.

[0074] The formation of ammonium cations from component C, which is an amine, is facilitated by the bonding of protons liberated from substituents of component B when the crosslinkable polymer composition is heated, or protons generated during the decomposition of component A, with component C. This occurs even at temperatures lower than those at which metal ions from component A are liberated. Furthermore, while one metal ion must bond with two substituents to form a crosslinked structure, the generated ammonium cation can inhibit crosslink formation by forming an ionic bond with only one substituent of component B. Therefore, the formation of ionic bonds between ammonium cations and substituents of component B proceeds at a lower temperature than the crosslinking reaction caused by metal ions liberated from component A and proceeds more rapidly than this crosslinking reaction, effectively competing with the crosslinking reaction and suppressing its rate. On the other hand, ammonium cations are bases that are softer than metal ions, making it difficult for them to form strong bonds with the substituents of component B, and difficult to form crosslinked structures by bonding with multiple substituents within component B. Therefore, even if ammonium cations are temporarily ionically bonded to the substituents of component B, during continued heating and kneading, the ammonium cations are gradually replaced by metal ions from component A, forming crosslinked structures between the polymer chains of component B. In the resulting crosslinked polymer material, the polymer chains of component B are crosslinked by the metal ions from component A, making it difficult for the polymer chains of component B to form a structure crosslinked via the ammonium cations from component C. While a portion of component C remains in the form of ammonium cations, ionically bonded to the substituents of component B, component C reverts to an amine state and is difficult to form a crosslinked structure.

[0075] As described above, the crosslinked polymer composition contains component C, and the crosslinked polymer material obtained by crosslinking component B due to the metal ions from component A becomes a material with excellent mechanical strength, such as wear resistance. High mechanical strength is required for polymer materials for various applications. For example, the crosslinked polymer material can be preferably used as the material for the insulating coating of insulated wires. The high mechanical strength of the insulating coating can suppress the effects of damage caused by contact with external objects. In addition, as mentioned above, the crosslinked product formed by components A and B is not easily affected by the reduction in flexibility caused by crosslinking due to the crosslinking due to the use of ionic bonds, and the addition of component C does not significantly impair the flexibility of the crosslinked product. In particular, if a material with sufficiently high flexibility is used as component B, the crosslinked polymer material also has high flexibility. Although the wear resistance of a crosslinked product using a highly flexible polymer material as component B is easily reduced, the addition of component C improves the wear resistance of the crosslinked polymer material as a whole, achieving both high flexibility and high wear resistance. If the insulating coating of an insulated wire is formed using a cross-linked polymer material having both high flexibility and high abrasion resistance, it is possible to achieve a high degree of compatibility between ensuring the bending flexibility of the insulated wire and suppressing the influence of damage.

[0076] Furthermore, in the crosslinked polymer material according to this embodiment, the crosslinked product formed from components A and B preferably has a flow start temperature within the range of 190°C to 300°C. When the flow start temperature of the crosslinked product is 190°C or higher, the crosslinked polymer material is less likely to experience increased fluidity and the accompanying irreversible deformation at temperatures below 190°C, resulting in high heat resistance. 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 is suitable for use in such insulation coatings. To effectively improve the heat resistance of the crosslinked polymer material, the flow start temperature of the crosslinked product is more preferably 200°C or higher, and more preferably 220°C or higher. On the other hand, when the flow start temperature of the crosslinked product is suppressed to 300°C or lower, the crosslinked polymer material can be easily reshaped by heating it to 300°C. From the perspective of effectively improving reformability, the flow initiation temperature of the crosslinked body is more preferably 280°C or lower, and even more preferably 250°C or lower. 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 as a solid material. For example, as shown in the examples below, it can be measured as the temperature at which an indenter can penetrate a sheet-like material. Alternatively, the material's melting point or pour point (or the lower of both, if present) can be considered the flow initiation temperature.

[0077] The cross-linked polymer material involved in this embodiment can have a wide range of tensile moduli based on the tensile modulus of the polymer material used as component B, and there is no particular limitation 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 80 MPa or less. More preferably, the tensile modulus is 50 MPa or less, and further preferably 20 MPa or less. There is no particular lower limit for the tensile modulus of the cross-linked polymer material, but from the perspective of ensuring sufficient mechanical strength, it can be 5 MPa or more, and further 10 MPa or more. On the other hand, in the cross-linked polymer material, in the case of particularly wanting to improve mechanical strength represented by wear resistance, the tensile modulus can be higher than 80 MPa. In particular, if the tensile modulus of the cross-linked polymer material is 200 MPa or more, and further 500 MPa or more, then particularly high mechanical strength can be obtained. In this case, from the perspective of ensuring flexibility, the tensile modulus can be suppressed to 1600 MPa or less. The tensile modulus can be measured by, for example, a tensile test based on JIS K 7161.

[0078] As described above, the crosslinkable polymer composition of this embodiment, after crosslinking, becomes a crosslinked polymer material having high heat resistance, furthermore, reformability, and high mechanical strength. Furthermore, even after crosslinking, it is not likely to cause a decrease in flexibility. To particularly improve these properties, the specific types and structures of components A, B, and C can be selected to be suitable. Furthermore, the mixing ratio of each component also affects their properties. The preferred structures, properties, etc. of each component are described below.

[0079] (2)A component

[0080] 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.

[0081] 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 such as below 50°C to prepare a crosslinkable polymer composition, or when the prepared crosslinkable polymer composition is stored, it is unlikely that the quality of the crosslinkable polymer composition will deteriorate due to unexpected release of metal ions from component A and the accompanying crosslinking of component B. 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 enhanced.

[0082] 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.

[0083] Furthermore, component A preferably has a decomposition point or phase transition point at a temperature above the flow start temperature of component B, described below. This allows component B to undergo crosslinking due to the metal ions released from component A, while component B already has fluidity, at a temperature at which component A releases metal ions. Consequently, crosslinking can proceed while the metal ions are well dispersed within component B, leveraging the fluidity of component B. This facilitates obtaining a crosslinked polymer material with highly uniform structural structure, characterized by a highly spatially distributed crosslinking point caused by the metal ions. This enhances the effect of crosslinking on mechanical strength, such as wear resistance. Furthermore, the unintended release of metal ions from component A and the accompanying crosslinking of component B are less likely to occur during the preparation of the crosslinkable polymer composition. More preferably, component A has a decomposition point or phase transition point at a temperature higher than the flow start temperature of component B, and further, at a temperature at least 10°C higher than the flow start temperature of component B. The decomposition point or phase transition point of component A is indicated by the baseline change onset temperature as measured by DSC. In addition, the above-mentioned phase transition point does not include the melting point, and the above-mentioned phase transition does not include melting. In the case where component A has both a phase transition point and a decomposition point, or in the case where it has multiple phase transition points, the lower one (the lowest one) among them is treated as the "decomposition point or phase transition point".

[0084] 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.

[0085] 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.

[0086] The metal species listed above as preferred substances are not limited. As long as the substance crosslinks the B component by forming an ionic bond between the metal ion and the substituent of the B component, and more preferably, as long as it can provide a crosslinked body with a flow start temperature of 190°C or higher and 300°C or lower, 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 crosslinked body with a flow start temperature higher than the above range. This is believed to be because, when a crosslinked body is formed using ions of metals with many available oxidation numbers or low ionization tendency, such as transition metals, the movement of crosslinking 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.

[0087] 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.

[0088] 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.

[0089] 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).

[0090]

[0091] In formula (2), R4 and R5 each independently represent a hydrocarbon group, and R6 represents a hydrogen atom or a hydrocarbon group. This also includes cases where at least two of R4, R5, and R6 are linked to each other via a ring structure. Furthermore, the ligand may also adopt the structure of formula (2) via a resonance structure.

[0092] In formula (2), R4, R5, and R6 may be aliphatic hydrocarbon groups or hydrocarbon groups containing aromatic rings. Furthermore, heteroatoms such as oxygen atoms may be contained. Examples of hydrocarbon groups constituting R4, R5, and R6 include alkyl groups, alkoxy groups, aromatic groups, and condensed aromatic groups. The number of carbon atoms in R4, R5, and R6 is not particularly limited, but is preferably 1 or more and 8 or less.

[0093] 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 R4 and R5 are methyl groups and R6 is a hydrogen atom are particularly preferred.

[0094] 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 and wear resistance. To enhance the effects of improving heat resistance and wear resistance, the content of component A is more preferably 1.0 parts by mass or greater, and more 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 makes it easier to avoid 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 is more easily 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 more preferably 10 parts by mass or less, relative to the aforementioned 100 parts by mass.

[0095] (3) Component B

[0096] 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.

[0097] As electron-withdrawing substituents capable of forming ionic bonds with metal ions, acidic groups other than hydroxyl groups such as carboxylic acid groups, acid anhydride groups, phosphoric acid groups, and acrylic acid groups can be appropriately exemplified. The substituent may be one 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, acid 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. Therefore, they have high uniformity in the structure of component B and can form a cross-linked structure. As a result, a high improvement in mechanical strength such as wear resistance caused by cross-linking can be obtained. 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 used as a substituent for component B as the substituents listed above as preferred substituents.

[0098] In component B, as described above, 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, so that 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. There are no particular restrictions on the structure and length of the side chain, 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 a heteroatom such as an oxygen atom. The substituent can be introduced into the end of the side chain or into the middle part, but from the perspective of effectively improving the degree of freedom of movement of the cross-linked site, it is preferably introduced into the end. There is no particular restriction on the upper limit of the number of carbon atoms in the side chain, but from the perspective of minimizing the influence on the physical properties of the main chain, the number of carbon atoms connected between 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, the structures of the particularly preferred side chain parts are represented by the following formulas (3) and (4), respectively.

[0099]

[0100]

[0101] Here, R7 is the main chain, R8 is an oxygen atom or an alkyl or alkylene group having 1 or more carbon atoms, and R9 is also 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 R8 or R9. Alternatively, multiple electron-withdrawing substituents may form an anhydride with each other.

[0102] 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 becomes smaller, making it difficult to obtain high reshaping properties. It is also difficult to obtain the effect of inhibiting the progress of the cross-linking reaction 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. In addition, component B preferably does not contain atoms capable of forming coordination bonds with metal ions, such as nitrogen atoms and sulfur atoms, in its side chain, while still retaining unshared electron pairs capable of coordination bonding. This is because when these atoms form coordination bonds with the metal ions released from component A, the ionic bonding between the electron-withdrawing functional group and the metal ion may be reduced.

[0103] 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.

[0104] The organic polymer of component B is an organic polymer such as resin, rubber, and elastomer. Preferably, from the viewpoint of formability during thermoforming such as extrusion molding, component B can be composed of a thermoplastic resin. In particular, from the viewpoint of ensuring high formability, flexibility, and high mechanical strength, olefin polymers or styrene polymers can be preferably used as the main chain constituting component B. Alternatively, acrylic polymers can also be used. Specific examples of polymers constituting the main chain of component B include: polypropylene, polyethylene, polybutene, polybutadiene, polypentene, polyhexene, polymethylpentene, polyoctene, polymethyl methacrylate, or copolymers containing monomers constituting these polymers, styrene-ethylene-butylene-styrene block copolymers (SEBS), and other styrene-based thermoplastic elastomers. From the viewpoints of availability and chemical resistance, among the listed substances, polypropylene, polyethylene, various ethylene-α-olefin copolymers, styrene-based thermoplastic elastomers, and other ethylene-based copolymers can be particularly preferably used. As component B, only one type can be used, or two or more types can be mixed and used. To achieve particularly high mechanical strength, among the above-mentioned substances, substances imparting a high tensile modulus, such as polypropylene, can be used as the main chain. On the other hand, to achieve particularly high flexibility, among the above-mentioned substances, substances imparting a low tensile modulus, such as ethylene-methyl acrylate copolymer (EMA) and ethylene-vinyl acetate copolymer (EVA), styrene-based thermoplastic elastomers, and low-density polyethylene, can be used as the main chain.

[0105] The polymeric species constituting the main chain of component B are not limited to those listed above. As described above, it is preferred that the main chain contain no electron-withdrawing groups. Furthermore, from the perspective of ensuring thermoplasticity, flexibility, and chemical resistance, component B preferably does not contain ether bonds or cyclic structures in the main chain. In other words, the main chain of component B preferably has a backbone in which carbon atoms are connected in a linear or branched chain.

[0106] Component B is preferably composed of an organic polymer with a low glass transition temperature. Specifically, the glass transition temperature can be 10°C or less. Thus, in the cross-linked body, it is easy to take into account both high flexibility and high mechanical strength. More preferably, the glass transition temperature is 0°C or less, and further can be -20°C or less, -40°C or less. In this embodiment, the cross-linked polymer composition contains component C, and the cross-linked polymer material becomes a material with excellent mechanical strength such as wear resistance. Therefore, in order to improve the mechanical strength of the cross-linked polymer material, it is not necessary to use a material with a high glass transition temperature as component B. Therefore, there is no particular lower limit for the glass transition temperature of component B, but from the viewpoint of ensuring high mechanical strength in the cross-linked polymer material, it can be -90°C or more, and further -70°C or more. The glass transition temperature of component B can be evaluated, for example, according to JIS K7121. It should be noted that, in the case of a cross-linked polymer material, when mechanical strength, particularly abrasion resistance, is particularly desired to be improved, it is preferable to use a material having a relatively high glass transition temperature, such as greater than 0°C, or even greater than 10°C, even within a range of 10°C or less, as component B. However, even in this case, from the perspective of ensuring the flexibility of the cross-linked polymer material, the glass transition temperature of component B can be suppressed to 20°C or less.

[0107] Component B preferably has a flow start temperature within the range of 50°C to 190°C. This facilitates obtaining a crosslinked product having a flow start temperature at a moderately high temperature, 190°C to 300°C, through crosslinking caused by metal ions released from component A. The flow start temperature of component B is more preferably 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 a cross-linked polymer material, when mechanical strength, such as wear resistance, is particularly desired to be improved, it is preferable to use a material having a Shore D hardness of more than 40, or even more than 60, as component B, even if the Shore D hardness is within the range of 60 or less. 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] Component C is composed of a secondary or tertiary amine represented by formula (1) shown again below.

[0111]

[0112] Here, R1 is a hydrogen atom or a hydrocarbon group having 30 or less carbon atoms, R2 is a hydrocarbon group having 30 or less carbon atoms, and R3 is a hydrocarbon group having 13 or more and 30 or less carbon atoms. When R1 is a hydrogen atom, component C is a secondary amine, and when R1 is a hydrocarbon group, component C is a tertiary amine. Hereinafter, when referring to the structure of a hydrocarbon group, R1, unless otherwise specified, refers to the embodiment of a hydrocarbon group other than a hydrogen atom.

[0113] As described above, by adding an amine-based component C to the crosslinkable polymer composition, the ammonium cations formed by component C bind to the electron-withdrawing substituents of component B, thereby suppressing the crosslinking reaction of component B by the metal ions released from component A, thereby improving the spatial uniformity and degree of crosslinking of the crosslinked structure. By limiting component C to secondary or tertiary amines, the formation of irreversible covalent bonds with the substituents of component B, which can occur in the case of primary amines, can be avoided. As a result, component C can effectively contribute to suppressing the crosslinking rate by forming ionic bonds with component B, and these ionic bonds can be reversibly released, thereby maintaining the substituents of component B in a state capable of forming ionic bonds with the metal ions released from component A to form a crosslinked structure. Examples of covalent bond formation that may occur when component C is a primary amine include the formation of an imine structure when the substituents of component B are carboxylic acid groups or carboxylic anhydride groups. Component C can use either secondary or tertiary amines, but secondary amines are preferred because they are often solid at room temperature and easy to handle.

[0114] In formula (1), at least one hydrocarbon group, i.e., at least R3, has a carbon number of 13 or more. Thus, component C is not easily volatile during the heating and kneading of the crosslinkable polymer composition. In addition, since the polarity of component C is not too high, its compatibility with component B becomes higher. Since component C is not easily volatile and exhibits high compatibility with component B, component C is uniformly and stably distributed in component B. Therefore, component C inhibits the crosslinking reaction caused by components B and A, thereby achieving a high effect of improving the mechanical strength of the crosslinked polymer material. There is no particular restriction on the lower limit of the carbon number of the other two hydrocarbon groups, i.e., R1 and R2, but these carbon numbers are also preferably 13 or more. In addition, it is more preferred that the carbon number of R3 (and R1 and R2) can be 15 or more. On the other hand, since the carbon number of the hydrocarbon groups of R1, R2, and R3 is respectively 30 or less, component C is easily ionically bonded to the electron-withdrawing substituent of component B in the form of an ammonium cation during the heating and kneading of the crosslinkable polymer composition. R1, R2, and R3 may all be composed of the same hydrocarbon group, or at least two of them may be composed of different hydrocarbon groups. From the viewpoint of the availability of amines, it is preferred that two or three of them be composed of the same hydrocarbon group.

[0115] The hydrocarbon groups constituting the amine of component C are each independently preferably an alkyl group or an aromatic ring group. As a result, the steric hindrance near the nitrogen atom of component C is suppressed to be small, and a high effect of suppressing the reaction rate of the cross-linking reaction caused by components A and B can be obtained. From the perspective of further improving this effect, when the hydrocarbon group is an alkyl group, it is preferred that the alkyl group is straight-chain. In addition, as long as the aromatic ring group contains an aromatic ring, there is no particular limitation on the presence or absence of a hydrocarbon portion other than the aromatic ring and the number of aromatic rings. However, from the same perspective, the number of aromatic rings in each hydrocarbon group is preferably 2 or less. In addition, the aromatic ring is preferably directly bonded to the nitrogen atom.

[0116] Component C is preferably a monoamine containing only one amine structure in the molecule. This reduces the likelihood of crosslinking between polymer chains of component B via component C, which may occur when the component has multiple amine structures, and the crosslinked structure is primarily formed via the metal ions derived from component A.

[0117] Specific examples of component C include the following. Specifically, secondary amines include N-methyltetradecylamine, N-methylhexadecylamine, N-methylstearylamine, N-methylbehenylamine, N-methyloctadecylamine, N,N-distearylamine, diphenylamine, 4-methyldiphenylamine, 3-methyldiphenylamine, ditolylamine, N-phenylnaphthylamine, N-tolylnaphthylamine, 4,4'-bis(α,α-dimethylbenzyl)diphenylamine, 6-ethoxy-2,2,4-trimethyl-1,2-dihydroquinoline, and bis(4-octylphenyl)amine. Examples of tertiary amines include N,N-dimethyltetradecylamine, N,N-dimethylhexadecylamine, N,N-dimethylstearylamine, N,N-dimethylbehenylamine, N,N-dimethyloctadecylamine, N,N-distearylmethylamine, N-methyldiphenylamine, triphenylamine, methyltriphenylamine, and N,N-diphenylnaphthylamine. From the perspectives of availability and reduction of odor at high temperatures, N,N-dimethylstearylamine, N-methylstearylamine, 4,4'-bis(α,α-dimethylbenzyl)diphenylamine, and bis(4-octylphenyl)amine are particularly preferred. Component C may be used alone or in combination of two or more.

[0118] In the cross-linkable polymer composition, the total amount of component A, component B, and component C is set to 100 parts by mass, and the content of component C can be 0.5 parts by mass or more. Thus, by component C, a high effect of suppressing the reaction rate of the cross-linking reaction generated by components A and B can be obtained. It is further preferred that the content of component C be 0.8 parts by mass or more, or 1.0 parts by mass or more relative to the above 100 parts by mass. On the other hand, the content of component C can be 20 parts by mass or less relative to the above 100 parts by mass. Thus, the formation of aggregates caused by component C can be avoided. In addition, by containing a relatively sufficient amount of component B, the physical properties brought by component B, such as mechanical strength and low-temperature characteristics, are fully exhibited in the cross-linked polymer material. It is further preferred that the content of component C be 10 parts by mass or less, or 5 parts by mass or less relative to the above 100 parts by mass.

[0119] (5) Other ingredients

[0120] The cross-linkable polymer composition involved in this embodiment can contain additives such as flame retardants, copper poison inhibitors, antioxidants, and colorants as appropriate, in addition to the above-mentioned components A, B, and C, within the range that does not hinder the function of the material. As other additives, metal salts of long-chain carboxylic acids having a structure represented by the following formula (5) and a melting point of 190°C or above can be cited. When the compound is melted and liquefied in the cross-linkable polymer composition, it improves the heat deformability of the cross-linkable polymer composition by improving the fluidity of the cross-linked body composed of components A and B. When the cross-linkable polymer composition is subjected to heat forming such as extrusion molding, it is easy to heat-form into a desired shape. As the amount of the compound added, the total amount of components A and B is set to 100 parts by mass, and the range of 1.0 parts by mass or more and 30 parts by mass or less can be exemplified.

[0121]

[0122] 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+ represents a metal ion with a valence of y, y is an integer greater than 1, and x=y. Figure 1 R and M of A to 1C are irrelevant.

[0123] In addition, organic polymers other than component B may be contained as polymer components, but their content is preferably suppressed to be less than the content of component B. It is further preferred that the crosslinkable polymer composition contains only component B as a polymer component. In addition, as components that are preferably not contained in the crosslinkable 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 crosslinkable polymer composition contains compounds of groups (a) to (d), when heated, there is a possibility that undesirable chemical reactions such as crosslinking of component B and breaking of the main chain of component B caused by reactions different from the crosslinking reaction via the metal ions released from component A will occur. As a result, the heat resistance and reshaping properties of the crosslinkable polymer composition may not be fully exerted. In addition, when the crosslinkable polymer composition contains the compound of group (e), it is possible to cause coloring and the generation of corrosive gases due to heating. When the crosslinkable polymer composition contains the compound of group (f), when the composition is formed, it is possible to cause ignition and the generation of bubbles. In addition, when the crosslinkable polymer composition contains organic low molecules (non-polymerized organic molecules), from the viewpoint of fully ensuring the thermoplasticity, flexibility and chemical resistance of the polymer material after crosslinking, the organic low molecules are also the same as component B, preferably do not contain ether bonds or cyclic structures represented by steroid skeletons.

[0124] A crosslinkable 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 crosslinkable polymer composition can then be subjected to heat-forming, such as extrusion, to form it into any desired shape. If heat-mixing and heat-forming are performed at a temperature above the decomposition point or phase transition point of component A, the crosslinkable polymer composition can be formed into a predetermined shape while a crosslinked structure has already been formed from components A and B, or while the crosslinked structure is being formed. In this case, additional heating for crosslinking is not required after forming. Furthermore, the temperature during heat-mixing and heat-forming can be set to a temperature above the flow start temperature of the crosslinked structure formed from components A and B. This allows heat-mixing and heat-forming to be performed smoothly while the material is fluid. Even after the crosslinked polymer material is temporarily formed into a predetermined shape, the formed structure can be heated to a temperature above the flow start temperature of the crosslinked structure to obtain fluidity and be reshaped. Reshaping can be repeated reversibly. The cross-linkable polymer composition involved in this embodiment can form a cross-linked structure even without performing any operation other than heating. Therefore, compared with the case of using electron beam cross-linking or silane cross-linking, the cross-linking process can be implemented with simple equipment. Since the reshaping process can also be carried out by applying an appropriate external force while heating, it can also be implemented with simple equipment. It should be noted that in the cross-linked polymer material in which the cross-linking of component B is completed by the metal ions from component A, most of component C returns to the state of amine and coexists with the cross-linked body. Even if the cross-linked polymer material is heated for reshaping, it is not easy to form an ionic bond between the electron-withdrawing substituent of component B in the form of ammonium ions.

[0125] [2]Insulated wires and wiring harnesses

[0126] The crosslinked polymer material formed from the crosslinkable polymer composition of this embodiment can be used to construct any component. However, due to its excellent wear resistance, high heat resistance and formability, and its resistance to loss of flexibility due to crosslinking, the crosslinked polymer material of this embodiment can be suitably used as a component material for insulated wires and wiring harnesses for automotive applications, etc. In insulated wires and wiring harnesses, heat is easily generated by passing electricity through metal components, such as wire conductors. Therefore, polymer materials arranged near these metal components are also required to have high heat resistance, such as resistance to irreversible deformation, when heated. On the other hand, when forming the crosslinkable polymer composition into a desired shape through heat forming such as extrusion, it is desirable that the crosslinkable polymer composition has high fluidity and excellent formability. Furthermore, depending on requirements such as deformation of the insulated wire or changes in the composition of the wiring harness, it is sometimes necessary to reshape the polymer material that has already been formed into a predetermined shape.

[0127] 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 used to bundle multiple insulated wires in a wiring harness, wire protective materials, and waterproof plugs used to waterproof connectors. Among these, the insulating coating of the insulated wire is preferably formed from the cross-linked polymer material according to the embodiments of the present disclosure. The insulating coating is required to have high mechanical strength that is not easily damaged even by contact with external objects such as other wires, and, as described below, to be able to effectively utilize reformability.

[0128] 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.

[0129] 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 embodiments of the present disclosure described above and has high heat resistance. Therefore, even if the insulating coating 3 is heated, it is unlikely to be affected by heat, such as irreversible deformation.

[0130] 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, the insulating coating 3 is obtained in a state where a cross-linked body of components A and B is formed by extrusion molding. In addition, if the temperature during extrusion molding is set to a temperature above the flow start temperature of the cross-linked body formed by components A and B, extrusion molding can be carried out smoothly. If the flat portion is not formed and the insulated wire is used, the round wire obtained by extrusion molding can be directly used.

[0131] 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. 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 and thus easily deforms following the deformation of the wire conductor 2. The insulating coating 3 can then be naturally cooled and returned to its original stable cross-linked state. Alternatively, in the already formed flat portion, by applying a compressive force from both sides in the width direction while heating the insulating coating 3 to a temperature above the flow start temperature of the cross-linked body, the flat portion can be restored to the shape of a round wire or a shape close to it with low flatness. In this case, the insulating coating 3 also follows the deformation of the wire conductor 2 and deforms into a shape with low flatness.

[0132] In this way, by forming the insulating coating 3 from a cross-linked polymer composition containing components A and B, and extruding it onto the outer periphery of the wire conductor 2, an insulating coating 3 with excellent heat resistance and mechanical strength can be easily formed. In addition, by forming the insulating coating 3 from a cross-linked body with reversible reshaping properties, the insulating coating 3 can be deformed to follow the deformation of the wire conductor 2, and the insulated wire 1 can be easily deformed into any shape, such as a two-way deformation between a flat cross-section and a roughly circular cross-section. For example, in the configuration path, the cross-sectional shape of the insulated wire can be changed with a high degree of freedom, such as forming a flat portion on a round wire, only in the area where space saving is required. Thus, for example, various insulated wires with flat portions in different locations can be produced using a common wire as raw material. 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, and used in the form of a wire harness containing insulated wires.

[0133] Example

[0134] 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.

[0135] <Sample Preparation>

[0136] In order to prepare samples A1 to A17 and samples B1 to B15, component A, component B and component C were kneaded in the formulations (parts by mass) described in Tables 1 and 2, respectively. 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 A17, 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.

[0137] The materials used are as follows.

[0138] (1)A component

[0139] Hereinafter, the material type is shown, and the decomposition point or phase transition point obtained by DSC measurement is shown in parentheses.

[0140] ･Ca-AA: Calcium(II) acetylacetonate (110℃)

[0141] ･Zn-AA: Zinc(II) acetylacetonate (105℃)

[0142] ･Al-AA: Aluminum(III) acetylacetonate (112℃)

[0143] ･Zr-AA: Zirconium(IV) acetylacetonate (180℃)

[0144] ･ZnO: Zinc (II) oxide (None (>300℃))

[0145] ･stCa: Calcium stearate (93℃)

[0146] (2) Component B

[0147] The following summarizes the material types, flow start temperature (measured in the same manner as described in the evaluation method section below), hardness (Shore D hardness measured in accordance with JIS K 6253), and glass transition temperature (measured in accordance with JIS K 7121).

[0148] MAH-SEBS: Maleic acid-modified hydrogenated styrene thermoplastic elastomer, "M1911" manufactured by Asahi Kasei Corporation, flow start temperature 142°C, D hardness 36, glass transition temperature -51°C

[0149] MAH-EO: Maleic acid-modified ethylene-α-olefin copolymer, "MH5020" manufactured by Mitsui Chemicals, Inc., flow start temperature 132°C, D hardness 15, glass transition temperature -49°C

[0150] MAH-EMA: Maleic acid-modified ethylene-methyl acrylate copolymer, "OREVAC 18603" manufactured by SK Functional Polymers, flow start temperature 83°C, D hardness 29, glass transition temperature -52°C

[0151] MAH-EVA: Maleic acid-modified ethylene-vinyl acetate copolymer, "OREVAC 18211" manufactured by SK Functional Polymers, flow start temperature 42°C, D hardness 10, glass transition temperature -42°C

[0152] MAH-LLDPE: Maleic acid-modified low-density polyethylene, "OREVAC18302N" manufactured by SK Functional Polymers, flow start temperature 95°C, D hardness 18, glass transition temperature -42°C

[0153] MAH-PP: Maleic acid-modified polypropylene, "ADMER QB550" manufactured by Mitsui Chemicals, flow start temperature 142°C, D hardness 58, glass transition temperature 4°C

[0154] AA-PP: Acrylic-modified polypropylene, "POLYBOND 1001" manufactured by Chemtura, flow start temperature 139°C, D hardness 45, glass transition temperature 8°C

[0155] EMAA: Ethylene methacrylic acid copolymer, "N035C" manufactured by Mitsui-Dow Polychemicals, flow start temperature 65°C, D hardness 41, glass transition temperature 29°C

[0156] SEBS: Hydrogenated styrene-based thermoplastic elastomer, "H1041" manufactured by Asahi Kasei Corporation, flow start temperature 137°C, D hardness 36, glass transition temperature -53°C

[0157] (3) C component

[0158] The types of materials are shown below: DMBA manufactured by Kao Chemical Co., Ltd. was used, and other materials manufactured by Tokyo Chemical Industry Co., Ltd. were used.

[0159] ･DMSA: N,N-dimethylstearylamine

[0160] ･DMBA: N,N-dimethylbehenylamine

[0161] ･TPA: Triphenylamine

[0162] ･MDPA: N-Methyldiphenylamine

[0163] ･MSA: N-Methylstearylamine

[0164] ･BDA: 4,4'-bis(α,α-dimethylbenzyl)diphenylamine

[0165] ･SA: Stearylamine

[0166] ･DMDA: N,N-dimethyldecylamine

[0167] Evaluation Method

[0168] (1) Flow start temperature

[0169] 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.

[0170] 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.

[0171] (2) Elastic modulus

[0172] 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.

[0173] (3) Wear resistance

[0174] A wear resistance test was performed on each sample. The sample pieces were cut into pieces of 50 mm in length × 30 mm in width × 2 mm in thickness and fixed on the table of a scratch resistance strength tester (manufactured by Shinto Science Co., Ltd.). Then, a sapphire stylus (R0.5 mm) with a load of 1 N applied in a direction perpendicular to the surface of the sample piece was reciprocated 1000 times on the surface of the sample piece at a speed of 55 times / minute over a length of 10 mm. Then, the depth of the center of the groove generated on the surface of the sample piece due to wear was measured using a laser microscope. The smaller the depth of the groove, the higher the wear resistance of the sample. If the depth of the groove is less than 250 μm, it can be considered that the wear resistance is sufficiently high.

[0175] (4) Gel fraction

[0176] The sample piece was finely cut, weighed to approximately 0.1 g as the initial mass, and placed in a sealed bottle. 20 mL of xylene was added and heated at 120°C for 24 hours. The sample was then cooled to room temperature, the gel fraction was filtered out, dried at 100°C, and the remaining gel mass was measured. The ratio of the remaining gel mass to the initial mass was calculated as the gel fraction (%). A higher gel fraction indicates a higher crosslinking density, and a gel fraction of 80% or higher is considered sufficiently high.

[0177] (4) Film appearance

[0178] The surface of the sample pieces was visually observed and evaluated for appearance. Sample pieces with uniform surface appearance were evaluated as having good appearance (A). On the other hand, sample pieces with uneven surface appearance due to separation of aggregates and incompatible materials were evaluated as having poor appearance (B).

[0179] <Evaluation Results>

[0180] In the following Tables 1 and 2, for Samples A1 to A17 and B1 to B15, 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.

[0181] [Table 1]

[0182]

[0183] [Table 2]

[0184]

[0185] According to Table 1, Samples A1 to A17 all contain a raw material, Component A, which releases metal ions by heat; Component B, which is an organic polymer containing electron-withdrawing substituents in its side chains capable of forming ionic bonds with metal ions; and Component C, which is a secondary or tertiary amine having the structure of the above formula (1). Furthermore, in these Samples A1 to A17, the flow start temperature of the sample sheets obtained by crosslinking during kneading and press molding was higher than the flow start temperature of Component B by more than 5°C, respectively, indicating that high heat resistance was achieved through crosslinking. The flow start temperature of the sample sheets was all above 190°C, also indicating that the crosslinked product has high heat resistance. Furthermore, while the molding temperature of a typical thermoplastic resin is approximately 300°C, the sample sheets of Samples A1 to A15 had a flow start temperature below 300°C, indicating that they had high reformability.

[0186] In addition, in samples A1 to A17, the depth of the groove in the wear test after cross-linking was less than 250 μm, which showed high wear resistance. In addition, in any of samples A1 to A17, the gel fraction was more than 80%, and a high cross-linking density was obtained. This can be explained by the contribution of component C suppressing the reaction rate of the cross-linking reaction between component A and component B, thereby increasing the cross-linking density and thus the cross-linked polymer material having high wear resistance. In addition, in each sample, the appearance of the sample was also good (A), and a uniform material was obtained without the formation of aggregates or the separation of incompatible substances. This also shows that there is no formation of uneven structures such as aggregates caused by the cross-linking reaction between component A and component B being carried out too quickly.

[0187] Samples A1 to A4 differed in the type of metal contained in component A, but all achieved high flow initiation temperature, low elastic modulus, high wear resistance, and gel fraction. Samples A1, A5, and A10 differed in the type of component B, but all achieved high flow initiation temperature, wear resistance, and gel fraction. Furthermore, samples A1, A5, and A8, as well as samples A2, A4, and A11, A17, which used the same component B as sample A1, had elastic moduli of 80 MPa or less after crosslinking, demonstrating both high flexibility and high wear resistance. Meanwhile, samples A9 and A10, which used a hard material with a polypropylene backbone as component B, exhibited higher elastic moduli after crosslinking. Furthermore, the groove depths in the wear test were 25 μm or less, demonstrating exceptionally high wear resistance.

[0188] Samples A1, A11, and A15 differed in the type of component C, but all exhibited high flow initiation temperature, low elastic modulus, high wear resistance, and a high gel fraction. Furthermore, Samples A1, A16, and A17 differed in the content of component C, but Sample A1, with a moderate content of component C, exhibited the highest flow initiation temperature, high wear resistance, and a low gel fraction. This is explained by the fact that Sample A1, by containing a sufficient amount of component C, exhibited a significant effect of suppressing the crosslinking reaction between components A and B. This, in turn, suppressed the formation of aggregates caused by the large amount of component C, resulting in a sufficient improvement in mechanical strength.

[0189] Among samples B1 to B15 shown in Table 2, samples B1, B2 to B7, and B8 differ from samples A1, A5 to A10, and A4 (hereinafter referred to as corresponding Group A samples) in that they do not contain component C. In these samples B1 to B8, crosslinking of component B occurs due to metal ions released from component A. Similar to the corresponding Group A samples, this crosslinking leads to an increase in flow temperature, resulting in high heat resistance. However, the groove depths in the wear resistance test were significantly greater than those of the corresponding Group A samples, particularly exceeding 250 μm in samples B1 to B5 and B8. In other words, the wear resistance of each of samples B1 to B8 was significantly lower than that of the corresponding Group A samples. The gel fraction was also low, below 80%. This can be explained by the fact that the absence of component C causes the crosslinking reaction between components A and B to proceed locally rapidly, preventing a uniform increase in the degree of crosslinking throughout the material. This results in a low gel fraction and hinders sufficient improvement in the mechanical strength of the crosslinked polymer material.

[0190] On the other hand, there were no significant differences in elastic modulus between samples B1 to B8 and their respective Group A samples. This suggests that the improvement in wear resistance due to the addition of component C is not simply due to an increase in elastic modulus, but rather to the increased uniformity and degree of crosslinking resulting from an increase in gel fraction, as described above. The fact that the addition of component C improves wear resistance with little increase in elastic modulus suggests that both the reduction in flexibility associated with crosslinking and the improvement in mechanical strength are simultaneously achieved at a high level.

[0191] Sample B9 contains no component A, preventing crosslinking of component B by metal ions. Consequently, its flow initiation temperature remains unchanged compared to that of component B and is below 190°C. Furthermore, its wear resistance is low, exceeding 500 μm in groove depth during testing. Its gel fraction is also less than 5%. In other words, the lack of crosslinking results in no improvement in heat resistance or wear resistance.

[0192] In samples B10 and B11, zinc oxide and calcium stearate, respectively, were used as component A, rather than a metal complex. These compounds do not liberate metal ions even when heated, and therefore cannot crosslink component B. Accordingly, in samples B10 and B11, as in sample B9, the flow start temperature did not show a significant increase from the value of component B and remained significantly below 190°C. Similarly to sample B9, the wear resistance and gel fraction were also very low. Thus, similar to sample B9, samples B10 and B11 did not undergo crosslinking, and thus failed to achieve the improvements in heat resistance and wear resistance that would be achieved through crosslinking.

[0193] In Sample B13, 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, similar to Samples B9-B11, the flow start temperature does not rise above the value of component B and remains significantly below 190°C. Furthermore, the wear resistance and gel fraction are also very low. Similarly to Samples B9-B11, Sample B13 also lacks crosslinking, and therefore fails to achieve the effects of crosslinking that improve heat resistance and wear resistance.

[0194] These samples B9 to B11 and B13 contain component C, but unlike component A, which releases metal ions, component C does not crosslink component B. In other words, the wear resistance improvement effect of component C, as confirmed in the comparison of samples B1 to B8 with the corresponding group A samples, is not due to the physical properties of component C itself, but is achieved by the coexistence of component C while the metal ions released from component A crosslink component B.

[0195] In sample B12, EMAA is used as component B, and it has a carboxylic acid group as an electron-withdrawing group in the main chain of the polymer, but does not have an electron-withdrawing substituent in the side chain. In the carboxylic acid group in the main chain, due to the steric hindrance of the adjacent methacryloyl group, a cross-linked structure via an ionic bond with the metal ion cannot be effectively formed. Correspondingly, the flow start temperature is significantly lower than 190°C. It can also be seen that the depth of the groove in the wear resistance test is greater than 250μm, and the gel fraction is less than 80%, and the improvement in heat resistance and wear resistance brought about by cross-linking does not effectively occur. In addition, it is believed that this is because the cross-linked structure is formed in the main chain of component B.

[0196] In sample B14, stearylamine (SA), a primary amine, was used as component C. In this sample B14, the flow start temperature also remained at a temperature lower than 190°C, the groove depth in the wear resistance test was greater than 500 μm, and the gel fraction was significantly lower than 80%. As a result, neither high heat resistance nor the wear resistance improvement effect brought about by the high cross-linking degree was obtained. In addition, the heat resistance, cross-linking degree, and wear resistance were all reduced compared to sample B1, which did not add an amine as component C. This can be explained by the fact that the primary amine added as component C reacts with the substituent of component B to form an imine structure, and the substituent of component B cannot form an ionic bond with the metal ion released from component A, and a cross-linking structure cannot be fully formed.

[0197] In sample B15, a tertiary amine was used as component C, but all hydrocarbon groups were short-chain N,N-dimethyldecylamine (DMDA) with fewer than 13 carbon atoms. In this sample B15, the appearance of the sample sheet deteriorated (B). This is believed to be due to the low compatibility between component C and component B, resulting in the separation of component C from component B into granules. Furthermore, the separation of granules is believed to prevent component C from effectively suppressing the reaction rate of the crosslinking reaction between components A and B and improving the spatial uniformity of the crosslinked structure. Consequently, the wear resistance was low and the gel fraction was also low.

[0198] 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.

[0199] Explanation of symbols

[0200] 1 Insulated wire

[0201] 2 Wire conductors

[0202] 21 single line

[0203] 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 the side chain contains an electron-withdrawing substituent capable of forming an ionic bond with the metal ion released from the component A; and Component C, wherein the component C is composed of a secondary or tertiary amine represented by the following formula (1), Here, R1 is a hydrogen atom or a hydrocarbon group having 30 or less carbon atoms, R2 is a hydrocarbon group having 30 or less carbon atoms, and R3 is a hydrocarbon group having 13 or more and 30 or less carbon atoms.

2. The cross-linkable polymer composition according to claim 1, wherein The cross-linked body has a flow starting temperature of 190° C. or higher and 300° C. or lower.

3. The cross-linkable polymer composition according to claim 1, wherein In the above formula (1), when R1 is a hydrocarbon group, the hydrocarbon group and the hydrocarbon groups of R2 and R3 are each independently a linear alkyl group or an aromatic ring group.

4. 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.

5. 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.

6. 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.

7. 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, R4 and R5 each independently represent a hydrocarbon group having 1 to 8 carbon atoms, and R6 represents a hydrogen atom or a hydrocarbon group having 1 to 8 carbon atoms, including a case where at least two of R4, R5, and R6 are connected to each other via a ring structure.

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

9. 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.

10. 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.

11. The cross-linkable polymer composition according to claim 1, wherein The component B has a glass transition temperature of 10° C. or lower.

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 main chain of the component B is an olefin polymer or a styrene polymer.

14. 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.

15. 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 0.5 parts by mass or more and 20 parts by mass or less of the component C.

16. 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 15. The cross-linked polymer material includes the component C and a cross-linked product obtained by cross-linking the component B using metal ions released from the component A.

17. The cross-linked polymer material according to claim 16, wherein The tensile elastic modulus of the cross-linked polymer material is less than 20 MPa.

18. 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 16 and covers the outer periphery of the electric wire conductor.

19. The insulated wire according to claim 18, 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.

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

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