High voltage-resistant insulating resin material, high voltage-resistant insulating molded product, and tracking resistance improver

Abstract

To provide a high voltage-resistant insulating resin material, a high voltage-resistant insulating molded product, and a tracking resistance improver.SOLUTION: An insulating resin material includes 5-30 mass% of (A) a polyamide resin including a constitutional unit represented by the formula below, and 95-70 mass% of (B) a polybutylene terephthalate resin.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a high-voltage insulating resin material, a high-voltage insulating molded article, and an agent for improving tracking resistance. [Background technology]

[0002] Polybutylene terephthalate resin (hereinafter sometimes abbreviated as PBT) has excellent electrical properties, chemical resistance, heat resistance, dimensional stability, etc., and is therefore widely used as a material for manufacturing various electrical and electronic equipment parts, interior and exterior components for vehicles such as automobiles, trains, and electric trains, and other general industrial products.

[0003] Electric vehicles use components to which a high voltage is applied during use (high-voltage components), and in this case, resin compositions used as materials for these high-voltage components are required to have high tracking resistance in order to suppress the tracking phenomenon. For example, Patent Document 1 discloses a polybutylene terephthalate resin material obtained by blending 100 parts by weight of (A) polybutylene terephthalate resin, 9 to 24 parts by weight of (B) polyamide resin, 6 to 44 parts by weight of (C) modified elastomer, 25 to 89 parts by weight of (D) glass fiber, and 0.05 to 1.7 parts by weight of (E) carbon black. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2020-076023 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, it has been found that even when a polyamide resin is blended with a polybutylene terephthalate resin, the tracking resistance at high voltages may not be sufficient. The present invention has an object to solve the above-mentioned problems, and to provide a high-voltage insulating resin material, a high-voltage insulating molded product, and an agent for improving tracking resistance. [Means for solving the problem]

[0006] In light of the above problems, the present inventors have conducted research and found that the above problems can be solved by blending a specific polyamide resin with a polybutylene terephthalate resin. Specifically, the above problems were solved by the following means. <1> A high-voltage insulating resin material comprising 5 to 30 mass % of a polyamide resin (A) containing a structural unit represented by formula (X) and 95 to 70 mass % of a polybutylene terephthalate resin (B) (provided that the total of components (A) and (B) does not exceed 100 mass %). Formula (X) [ka] (In formula (X), R 1 ~R 8 each independently represents a hydrogen atom or an aliphatic group having 1 to 5 carbon atoms; Cy represents a benzene ring, a naphthalene ring, or a cyclohexane ring; each n1 independently represents an integer of 0 to 2, and each n2 independently represents 0 or 1; ad represents an amide bond. <2> the polyamide resin (A) contains a diamine-derived structural unit and a dicarboxylic acid-derived structural unit, 70 mol % or more of the diamine-derived structural units are structural units represented by formula (X). <1> 2. A high voltage insulating resin material according to claim 1. <3> the polyamide resin (A) contains a diamine-derived structural unit and a dicarboxylic acid-derived structural unit, The diamine-derived structural unit includes a diamine-derived structural unit represented by formula (Y). <1> or <2> 2. A high voltage insulating resin material according to claim 1. Formula (Y) [ka] (In formula (Y), R 1 ~R 8 each independently represents a hydrogen atom or an aliphatic group having 1 to 5 carbon atoms; each n independently represents an integer of 0 to 2. <4> the polyamide resin (A) contains a diamine-derived structural unit and a dicarboxylic acid-derived structural unit, The diamine-derived structural unit includes a xylylenediamine-derived structural unit. <1> or <2> 2. A high voltage insulating resin material according to claim 1. <5> the polyamide resin (A) contains a diamine-derived structural unit and a dicarboxylic acid-derived structural unit, 30 mol % or more of the dicarboxylic acid-derived structural units are structural units derived from an aliphatic dicarboxylic acid having 4 to 20 carbon atoms. <1> ~ <4> 10. The high-voltage insulating resin material according to claim 9, <6> the polyamide resin (A) contains a diamine-derived structural unit and a dicarboxylic acid-derived structural unit, The dicarboxylic acid-derived structural unit includes at least one of adipic acid, sebacic acid, and dodecanedioic acid. <1> ~ <5> 10. The high-voltage insulating resin material according to claim 9, <7> the polyamide resin (A) contains a diamine-derived structural unit and a dicarboxylic acid-derived structural unit, 70 mol % or more of the diamine-derived structural units are xylylenediamine-derived structural units, 70 mol % or more of the dicarboxylic acid-derived constitutional units are at least one of adipic acid, sebacic acid, and dodecanedioic acid. <1> 2. A high voltage insulating resin material according to claim 1. <8> The insulating resin material has a breakdown time of 75 minutes or more at a voltage of 2000 V according to the JIS-C2136 constant voltage tracking method. <1> ~ <7> 10. The high-voltage insulating resin material according to claim 9, <9> <1> ~ <8> 1. A high-voltage insulating molded product formed from the high-voltage insulating resin material according to any one of claims 1 to 9. <10> An agent for improving the tracking resistance under high pressure for a polybutylene terephthalate resin, comprising a polyamide resin (A) containing a structural unit represented by formula (X). Formula (X) [ka] (In formula (X), R 1 ~R 8 each independently represents a hydrogen atom or an aliphatic group having 1 to 5 carbon atoms; Cy represents a benzene ring, a naphthalene ring, or a cyclohexane ring; each n1 independently represents an integer of 0 to 2, and each n2 independently represents 0 or 1; ad represents an amide bond. Effect of the Invention

[0007] The present invention makes it possible to provide a high-voltage insulating resin material, a high-voltage insulating molded article, and an agent for improving tracking resistance. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Hereinafter, an embodiment of the present invention (hereinafter, simply referred to as "the present embodiment") will be described in detail. Note that the present embodiment is an example for explaining the present invention, and the present invention is not limited to the present embodiment. In this specification, the use of "to" means that the numerical values ​​before and after it are included as the lower limit and upper limit. In this specification, various physical properties and characteristic values ​​are those at 23° C. unless otherwise specified. In the description of groups (atomic groups) in this specification, when the description does not indicate whether the group is substituted or unsubstituted, the description also includes groups (atomic groups) that have a substituent as well as groups (atomic groups) that have no substituent. For example, the term "alkyl group" includes not only alkyl groups that have no substituent (unsubstituted alkyl groups), but also alkyl groups that have a substituent (substituted alkyl groups). In this specification, when the description does not indicate whether the group is substituted or unsubstituted, the description is preferably unsubstituted. If the measurement methods, etc. described in the standards shown in this specification vary from year to year, they will be based on the standards as of January 1, 2022, unless otherwise stated.

[0009] The high-voltage insulating resin material of this embodiment (hereinafter, simply referred to as "the insulating resin material of this embodiment") is characterized by containing 5 to 30 mass % of a polyamide resin (A) containing a structural unit represented by formula (X) and 95 to 70 mass % of a polybutylene terephthalate resin (B) (however, the total of the (A) component and the (B) component does not exceed 100 mass %). Formula (X) [ka] (In formula (X), R 1 ~R 8 each independently represents a hydrogen atom or an aliphatic group having 1 to 5 carbon atoms; Cy represents a benzene ring, a naphthalene ring, or a cyclohexane ring; each n1 independently represents an integer of 0 to 2, and each n2 independently represents 0 or 1; ad represents an amide bond. By adopting such a configuration, a resin material having excellent insulating properties at high withstand voltages, excellent mechanical strength, and excellent chemical resistance can be obtained. Tracking failure occurs when carbonized regions are formed when a voltage is applied between electrodes, and the carbonized regions are connected. In this embodiment, the presence of a specific polyamide resin between polybutylene terephthalate resins suppresses the growth of the carbonized regions and successfully improves tracking resistance. In particular, tracking resistance when a high voltage is applied is successfully improved. Generally, the more aromatic rings there are, the easier it is to form a carbonized conductive path, and therefore the tracking resistance is reduced. However, in this embodiment, surprisingly, by blending a resin with many aromatic rings, a resin material with excellent insulation properties at high withstand voltages is obtained. The reason for this is that it is expected that the application of high voltage will cause some progress in electrolysis of the polluting liquid, and so not only resistance to simple voltage but also resistance to the polluting liquid and electrolysis products is required, and it is presumed that the use of a resin with a certain amount of aromatic rings improves insulation properties at high withstand voltages.

[0010] <Polyamide resin (A) containing a structural unit represented by formula (X)> The insulating resin material of this embodiment contains polyamide resin (A) containing a constitutional unit represented by formula (X) in a proportion of 5 to 30 mass % relative to 100 mass % of the insulating resin material. Formula (X) [ka] (In formula (X), R 1 ~R 8 each independently represents a hydrogen atom or an aliphatic group having 1 to 5 carbon atoms; Cy represents a benzene ring, a naphthalene ring, or a cyclohexane ring; each n1 independently represents an integer of 0 to 2, and each n2 independently represents 0 or 1; ad represents an amide bond.

[0011] In formula (X), R 1 ~R 8 each independently represents a hydrogen atom or an aliphatic group having 1 to 5 carbon atoms, and each independently is preferably a hydrogen atom or a methyl group. In formula (X), Cy represents a benzene ring, a naphthalene ring, or a cyclohexane ring, preferably a benzene ring or a naphthalene ring, more preferably a benzene ring. The benzene ring, the naphthalene ring, or the cyclohexane ring may have a substituent, but preferably has no substituent. When it has a substituent, it is preferably an aliphatic group having 1 to 5 carbon atoms, more preferably a methyl group. In addition, as the substituent, a form having no phenolic hydroxyl group is exemplified.

[0012] In formula (X), n1 each independently represents an integer of 0 to 2, preferably 0 or 1, and more preferably 0. In formula (X), n2 is 0 or 1, and 1 is preferred. In formula (X), Cy is preferably linked to the para or meta position. The polyamide resin (A) used in the present embodiment may contain only one type of constitutional unit represented by formula (X), or may contain two or more types.

[0013] In this embodiment, the polyamide resin (A) contains a diamine-derived structural unit and a dicarboxylic acid-derived structural unit, and preferably 30 mol% or more of the diamine-derived structural unit are structural units represented by formula (X) (preferably, a diamine-derived structural unit represented by formula (Y) described later, and further, a xylylenediamine-derived structural unit), more preferably 70 mol% or more of the diamine-derived structural unit are structural units represented by formula (X), more preferably 80 mol% or more of the diamine-derived structural unit are structural units represented by formula (X), more preferably 90 mol% or more of the diamine-derived structural unit are structural units represented by formula (X), and even more preferably 95 mol% or more of the diamine-derived structural unit are structural units represented by formula (X). The structural unit represented by formula (X) may be one type, or two or more types.

[0014] In the present embodiment, the polyamide resin (A) contains a diamine-derived structural unit and a dicarboxylic acid-derived structural unit, and the diamine-derived structural unit preferably contains a diamine-derived structural unit represented by formula (Y). Formula (Y) [ka] (In formula (Y), R 1 ~R 8 each independently represents a hydrogen atom or an aliphatic group having 1 to 5 carbon atoms; each n independently represents an integer of 0 to 2.

[0015] In formula (Y), R 1 ~R 8 is R in formula (X) 1 ~R 8 The same definition and preferred range are also the same. Each n is independently preferably 0 or 1, and more preferably 0. In formula (y), the benzene ring is preferably a ring having the above-mentioned substituent (aminoalkyl group) at the para or meta position.

[0016] When the structural unit containing the formula (X) is a structural unit derived from diamine, the diamine constituting the structural unit derived from diamine is exemplified by xylylenediamine, benzenediethaneamine, benzenedipropaneamine, and bisaminomethylcyclohexane, and xylylenediamine and / or benzenediethaneamine are preferred, and xylylenediamine is more preferred. The preferred ratio of these diamines in the structural unit derived from diamine is as described above. As the xylylenediamine, metaxylylenediamine and / or paraxylylenediamine are more preferable. The molar ratio (m / p) of metaxylylenediamine to paraxylylene in the xylylenediamine is preferably 100-10 / 0-90, more preferably 100-30 / 0-70, even more preferably 100-60 / 0-40, and still more preferably 100-90 / 0-10. By adopting such a constitution, the insulating properties at high withstand voltage tend to be further improved. The benzenediethaneamine is preferably m-benzenediethaneamine and / or p-benzenediethaneamine, and more preferably p-benzenediethaneamine. By using such a composition, the insulating properties at high withstand voltage tend to be further improved. The benzenedipropanamine is preferably m-benzenedipropanamine and / or p-benzenedipropanamine, and more preferably p-benzenedipropanamine. By using such a constitution, the insulating property at high withstand voltage tends to be further improved. The bisaminomethylcyclohexane is preferably 1,3-bisaminomethylcyclohexane and / or 1,4-bisaminomethylcyclohexane, and more preferably 1,3-bisaminomethylcyclohexane.

[0017] In the polyamide resin (A) used in this embodiment, when the diamine-derived structural unit contains a structural unit represented by formula (X), a wide variety of known chain aliphatic diamines can be used as the diamine constituting the diamine-derived structural unit other than the structural unit represented by formula (X). An aliphatic diamine having 6 to 12 carbon atoms is preferred, and examples thereof include 1,6-hexanediamine, 1,7-heptanediamine, 1,8-octanediamine, 1,9-nonanediamine, and 1,10-decanediamine. Examples of the diamines include linear aliphatic diamines such as 1,11-undecanediamine and 1,12-dodecanediamine, and branched aliphatic diamines such as 2-methyl-1,8-octanediamine, 4-methyl-1,8-octanediamine, 5-methyl-1,9-nonanediamine, 2,2,4- / 2,4,4-trimethylhexamethylenediamine, 2-methyl-1,5-pentanediamine, 2-methyl-1,6-hexanediamine, and 2-methyl-1,7-heptanediamine.

[0018] In the present embodiment, when the polyamide resin (A) contains a diamine-derived structural unit and a dicarboxylic acid-derived structural unit, and the diamine-derived structural unit contains a structural unit represented by formula (X), the dicarboxylic acid-derived structural unit may or may not contain a structural unit represented by formula (X).

[0019] In this embodiment, the polyamide resin (A) contains diamine-derived structural units and dicarboxylic acid-derived structural units, and preferably 30 mol % or more of the dicarboxylic acid-derived structural units contain structural units derived from aliphatic dicarboxylic acids having 4 to 20 carbon atoms, more preferably 70 mol % or more of the dicarboxylic acid-derived structural units contain structural units derived from aliphatic dicarboxylic acids having 4 to 20 carbon atoms, even more preferably 80 mol % or more of the dicarboxylic acid-derived structural units contain structural units derived from aliphatic dicarboxylic acids having 4 to 20 carbon atoms, even more preferably 90 mol % or more of the dicarboxylic acid-derived structural units contain structural units derived from aliphatic dicarboxylic acids having 4 to 20 carbon atoms, and even more preferably 95 mol % or more of the dicarboxylic acid-derived structural units contain structural units derived from aliphatic dicarboxylic acids having 4 to 20 carbon atoms.

[0020] Examples of the aliphatic dicarboxylic acid having 4 to 20 carbon atoms include succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, and dodecanedioic acid. It is more preferable to include at least one of adipic acid, sebacic acid, and dodecanedioic acid, even more preferable to include adipic acid and / or sebacic acid, and even more preferable to include adipic acid.

[0021] In this embodiment, it is also preferred that the polyamide resin (A) contains a diamine-derived structural unit and a dicarboxylic acid-derived structural unit, and 30 mol% or more of the dicarboxylic acid-derived structural unit is a structural unit represented by formula (X). In such an embodiment, it is more preferred that the polyamide resin (A) contains a diamine-derived structural unit and a dicarboxylic acid-derived structural unit, and 70 mol% or more of the dicarboxylic acid-derived structural unit is a structural unit represented by formula (X), more preferably 80 mol% or more of the dicarboxylic acid-derived structural unit is a structural unit represented by formula (X), even more preferably 90 mol% or more of the dicarboxylic acid-derived structural unit is a structural unit represented by formula (X), and even more preferably 95 mol% or more of the dicarboxylic acid-derived structural unit is a structural unit represented by formula (X). Examples of dicarboxylic acids constituting the constituent unit represented by formula (X) as a dicarboxylic acid-derived constituent unit include isophthalic acid, terephthalic acid, orthophthalic acid, phenylene diacetic acid (o-phenylene diacetic acid, p-phenylene diacetic acid, m-phenylene diacetic acid), and naphthalene dicarboxylic acid (1,2-naphthalene dicarboxylic acid, 1,3-naphthalene dicarboxylic acid, 1,4-naphthalene dicarboxylic acid, 1,5-naphthalene dicarboxylic acid, 1,6-naphthalene dicarboxylic acid, 1,7-naphthalene dicarboxylic acid, 1,8-naphthalene dicarboxylic acid, 2,3-naphthalene dicarboxylic acid, 2,6-naphthalene dicarboxylic acid, and 2,7-naphthalene dicarboxylic acid). Among these, it is preferable to select from isophthalic acid, terephthalic acid, and phenylene diacetic acid (preferably p-phenylene diacetic acid), and terephthalic acid is more preferable.

[0022] When the polyamide resin (A) contains a diamine-derived structural unit and a dicarboxylic acid-derived structural unit, and 30 mol % or more of the dicarboxylic acid-derived structural units are structural units represented by formula (X), the diamine-derived structural units may or may not contain a structural unit represented by formula (X).

[0023] In addition, the polyamide resin (A) used in this embodiment preferably contains a dicarboxylic acid-derived structural unit and a diamine-derived structural unit, but may contain structural units other than the dicarboxylic acid-derived structural unit and the diamine-derived structural unit, and other sites such as terminal groups. Examples of other structural units include lactams such as ε-caprolactam, valerolactam, laurolactam, and undecalactam, and structural units derived from aminocarboxylic acids such as 11-aminoundecanoic acid and 12-aminododecanoic acid, but are not limited thereto. Furthermore, the polyamide resin (A) used in this embodiment may contain trace components such as additives used in the synthesis. The polyamide resin (A) used in the present embodiment is preferably composed of 70% by mass or more, more preferably 80% by mass or more, even more preferably 90% by mass or more, still more preferably 95% by mass or more, and even more preferably 98% by mass or more of dicarboxylic acid-derived structural units and diamine-derived structural units. The polyamide resin (A) used in this embodiment preferably has an amino group (-NH2) or a carboxylic acid group (-COOH) as a terminal group. The polyamide resin (A) may be capped with a terminal capping agent, and the terminal capping agent preferably has 8 or less carbon atoms.

[0024] A first embodiment of the polyamide resin (A) used in the present embodiment contains diamine-derived structural units and dicarboxylic acid-derived structural units, in which 70 mol % or more of the diamine-derived structural units contain diamine-derived structural units represented by formula (Y), and 70 mol % or more of the dicarboxylic acid-derived structural units contain at least one of adipic acid, sebacic acid, and dodecanedioic acid. A second embodiment of the polyamide resin (A) used in the present embodiment contains diamine-derived structural units and dicarboxylic acid-derived structural units, in which 70 mol % or more of the diamine-derived structural units contain diamine-derived structural units represented by formula (Y), and 70 mol % or more of the dicarboxylic acid-derived structural units contain adipic acid and / or sebacic acid (preferably adipic acid). The diamine represented by formula (Y) is preferably metaxylylenediamine, paraxylylenediamine, parabenzenediethaneamine, or 1,3-bisaminomethylcyclohexane, and more preferably metaxylylenediamine and / or paraxylylenediamine.

[0025] The polyamide resin (A) used in the present embodiment preferably does not have an imide group, that is, it is preferably not a polyamideimide.

[0026] The polyamide resin (A) in the high voltage insulating material of this embodiment preferably has a moisture content (hereinafter referred to as "humidified moisture content") of 1% by mass or more when measured according to the moisture evaporation method of JIS K 7251 after storing the polyamide resin (A) in an environment of 85°C / 85%RH for 300 hours. By making the moisture content equal to or more than the lower limit, resistance to highly lipophilic solvents such as gasoline tends to be improved. The water absorption rate of the polyamide resin (A) in the high voltage insulating material of this embodiment is also preferably 8% by mass or less. By making the moisture content equal to or less than the upper limit, resistance to acids and alkalis tends to be improved.

[0027] The formula weight (average value) of the constituent units of the polyamide resin (A) used in this embodiment is preferably 200 or more, more preferably 220 or more. This tends to improve the stability of the melt viscosity during molding. Also, it is preferably 500 or less, more preferably 350 or less, and even more preferably 280 or less. This tends to improve the mechanical strength. Also, the constituent units having a formula weight within the above range preferably account for 95% by mass or more of all the constituent units, more preferably 98% by mass or more, and even more preferably 99% by mass or more.

[0028] The number average molecular weight (Mn) of the polyamide resin used in the present embodiment is preferably 8,000 or more, and is preferably 50,000 or less, and more preferably 30,000 or less. The number average molecular weight (Mn) of polyamide resin can be measured by gel permeation chromatography (GPC) using a standard polymethyl methacrylate (PMMA) equivalent value. Two columns packed with styrene polymers are used as the packing material, and hexafluoroisopropanol (HFIP) with a sodium trifluoroacetate concentration of 2 mmol / L is used as the solvent. The resin concentration is 0.02 mass%, the column temperature is 40°C, the flow rate is 0.3 mL / min, and the measurement is performed using a refractive index detector (RI). In addition, the calibration curve is measured by dissolving six levels of PMMA in HFIP.

[0029] The polyamide resin (A) used in the present embodiment preferably has a glass transition temperature of 30° C. or higher and 100° C. or lower. The polyamide resin (A) used in this embodiment may be either a crystalline resin or a non-crystalline resin, but is preferably a crystalline resin. The melting point of the polyamide resin (A) used in this embodiment is preferably 180° C. or higher and 350° C. or lower.

[0030] In this specification, unless otherwise specified, the melting point (Tm) and the glass transition temperature (Tg) are values ​​measured by differential scanning calorimetry (DSC) in accordance with JIS K7121 and K7122. Specifically, a differential scanning calorimeter is used, the synthesized polyamide resin is crushed and placed in the measurement pan of the differential scanning calorimeter, the temperature is raised in a nitrogen atmosphere at a rate of 10°C / min to the melting point + 20°C shown in Table 1, and immediately after the temperature rise is completed, the measurement pan is removed and pressed against dry ice to rapidly cool, and then the measurement is performed. The measurement conditions are to raise the temperature to the melting point + 20°C at a rate of 10°C / min and hold for 5 minutes, and then to lower the temperature to 100°C at a rate of -5°C / min to determine the melting point (Tm) and glass transition temperature (Tg). As the differential scanning calorimeter, a "DSC-60" manufactured by Shimadzu Corporation can be used.

[0031] When the high withstand voltage insulating resin material of this embodiment contains two or more polyamide resins (A), the value is the sum of the values ​​obtained by multiplying each of the above physical property values ​​by the mass fraction of the polyamide resin (A).

[0032] The content of the polyamide resin (A) in the high-voltage insulating resin material of this embodiment is 5% by mass or more, preferably 6% by mass or more, more preferably 7% by mass or more, even more preferably 8% by mass or more, and even more preferably 9% by mass or more, based on 100% by mass of the insulating resin material. By making it equal to or more than the lower limit, the tracking resistance time tends to be longer. In addition, the upper limit of the content of the polyamide resin (A) is 30% by mass or less, preferably 25% by mass or less, more preferably 20% by mass or less, even more preferably 18% by mass or less, even more preferably 15% by mass or less, and even more preferably 12% by mass or less, based on 100% by mass of the insulating resin material. By making it equal to or less than the upper limit, the impact resistance tends to be excellent. The insulating resin material of the present embodiment may contain only one type of polyamide resin (A), or may contain two or more types. When two or more types are contained, the total amount is preferably within the above range.

[0033] <Polybutylene terephthalate resin (B)> The insulating resin material of this embodiment contains polybutylene terephthalate resin (B) in a ratio of 95 to 70 mass % relative to 100 mass % of the insulating resin material. The polybutylene terephthalate resin (B) is a resin obtained by polycondensing terephthalic acid as the main component of the acid component and 1,4-butanediol as the main component of the diol component. The main component of the acid component being terephthalic acid means that 50% by mass or more of the acid component is terephthalic acid, preferably 60% by mass or more, more preferably 70% by mass or more, and may be 80% by mass or more, 90% by mass or more, or 95% by mass or more. The main component of the diol component being 1,4-butanediol means that 50% by mass or more of the diol component is 1,4-butanediol, preferably 60% by mass or more, more preferably 70% by mass or more, and may be 80% by mass or more, 90% by mass or more, or 95% by mass or more. When the polybutylene terephthalate resin (B) contains other acid components, examples of the acid components include isophthalic acid and dimer acid. When the polybutylene terephthalate resin (B) contains other diol components, examples of the acid components include polyalkylene glycols such as polytetramethylene glycol (PTMG).

[0034] When a copolymer of polytetramethylene glycol is used as the polybutylene terephthalate resin (B), the proportion of the tetramethylene glycol component in the copolymer is preferably 3 to 40 mass%, more preferably 5 to 30 mass%, and even more preferably 10 to 25 mass%. By setting the copolymerization proportion in this range, the balance between laser weldability and heat resistance tends to be better, which is preferable.

[0035] When a dimer acid copolymerized polybutylene terephthalate is used as the polybutylene terephthalate resin (B), the ratio of the dimer acid component in the total carboxylic acid components is preferably 0.5 to 30 mol %, more preferably 1 to 20 mol %, and even more preferably 3 to 15 mol %, in terms of carboxylic acid groups. By setting the copolymerization ratio in this manner, the balance between laser weldability, long-term heat resistance, and toughness tends to be excellent, which is preferable.

[0036] When isophthalic acid copolymerized polybutylene terephthalate is used as the polybutylene terephthalate resin (B), the ratio of isophthalic acid components in the total carboxylic acid components is preferably 1 to 30 mol%, more preferably 1 to 20 mol%, and even more preferably 3 to 15 mol% as carboxylic acid groups. By setting the copolymerization ratio in this way, the balance of laser weldability, heat resistance, injection moldability, and toughness tends to be excellent, which is preferable.

[0037] The polybutylene terephthalate resin (B) used in the present embodiment is preferably a resin (polybutylene terephthalate homopolymer) in which 90% by mass or more of the acid component is terephthalic acid and 90% by mass or more of the diol component is 1,4-butanediol, or a copolymerized polybutylene terephthalate resin copolymerized with polytetramethylene glycol, or an isophthalic acid copolymerized polybutylene terephthalate resin.

[0038] The intrinsic viscosity of the polybutylene terephthalate resin (B) is preferably 0.5 dL / g or more, more preferably 0.6 dL / g or more, and is preferably 2.0 dL / g or less, more preferably 1.5 dL / g or less, and even more preferably 1.1 dL / g or less. By using a resin having an intrinsic viscosity of 0.5 dL / g or more, the mechanical strength of the resulting molded article tends to be improved. In addition, by using a resin having an intrinsic viscosity of 2 dL / g or less, the fluidity of the polybutylene terephthalate resin (B) tends to be improved, and moldability tends to be improved. The intrinsic viscosity of the polybutylene terephthalate resin (B) is a value measured at 30° C. in a mixed solvent of tetrachloroethane and phenol in a 1:1 (mass ratio). When two or more types of polybutylene terephthalate resins (B) are contained, the intrinsic viscosity is that of the mixture.

[0039] The amount of terminal carboxyl groups of the polybutylene terephthalate resin (B) may be appropriately selected and determined, but is usually 60 eq / ton or less, preferably 50 eq / ton or less, and more preferably 30 eq / ton or less. By setting the amount of terminal carboxyl groups to 50 eq / ton or less, the generation of gas during melt molding of the polybutylene terephthalate resin (B) can be more effectively suppressed. In addition, the lower limit of the amount of terminal carboxyl groups is not particularly specified, but is usually 5 eq / ton. When two or more kinds of polybutylene terephthalate resins (B) are contained, the amount of terminal carboxy groups is the amount of terminal carboxy groups of the mixture.

[0040] The amount of terminal carboxyl groups in the polybutylene terephthalate resin (B) is a value obtained by dissolving 0.5 g of the polybutylene terephthalate resin in 25 mL of benzyl alcohol and titrating with a 0.01 mol / L benzyl alcohol solution of sodium hydroxide. Methods for adjusting the amount of terminal carboxyl groups include any conventionally known methods, such as a method for adjusting polymerization conditions such as the raw material charge ratio during polymerization, polymerization temperature, and pressure reduction method, or a method for reacting a terminal blocking agent.

[0041] The content of the polybutylene terephthalate resin (B) in the high withstand voltage insulating resin material of this embodiment is 70% by mass or more, preferably 75% by mass or more, more preferably 80% by mass or more, even more preferably 82% by mass or more, even more preferably 85% by mass or more, and even more preferably 88% by mass or more, based on 100% by mass of the insulating resin material. By making it equal to or more than the lower limit, impact resistance tends to be improved. In addition, the content of the polybutylene terephthalate resin (B) in the high withstand voltage insulating resin material is 95% by mass or less, preferably 94% by mass or less, more preferably 93% by mass or less, even more preferably 92% by mass or less, and even more preferably 91% by mass or less, based on 100% by mass of the insulating resin material. By making it equal to or less than the upper limit, tracking resistance at high voltage tends to be further improved. The insulating resin material of the present embodiment may contain only one type of polybutylene terephthalate resin (B), or may contain two or more types. When two or more types are contained, the total amount is preferably within the above range.

[0042] The total amount of the polyamide resin (A) and the polybutylene terephthalate resin (B) in the high-voltage insulating resin material of this embodiment (100% by mass) is usually 90% by mass or more, preferably 95% by mass or more, more preferably 97% by mass or more, and even more preferably 99% by mass or more. The total amount of the polyamide resin (A) and the polybutylene terephthalate resin (B) does not exceed 100% by mass.

[0043] The high-voltage insulating resin material of the present embodiment may or may not contain a polyamide resin other than the polyamide resin (A). When a polyamide resin other than the polyamide resin (A) is contained, the other polyamide resin that the high withstand voltage insulating resin material of this embodiment can contain may be an aliphatic polyamide resin or a semi-aromatic polyamide resin. Examples of aliphatic polyamide resins include polyamide 6, polyamide 66, polyamide 46, polyamide 6 / 66 (a copolymer consisting of a polyamide 6 component and a polyamide 66 component), polyamide 610, polyamide 612, polyamide 410, polyamide 1010, polyamide 11, polyamide 12, and polyamide 9C (a polyamide consisting of a mixed diamine consisting of 1,9-nonanediamine and 2-methyl-1,8-octanediamine, and 1,4-cyclohexanedicarboxylic acid). When the high withstand voltage insulating resin material of the present embodiment contains a polyamide resin other than the polyamide resin (A), the content thereof is preferably 1 to 10 mass% relative to 100 mass% of the polyamide resin (A). The polyamide resin other than the polyamide resin (A) may be contained in one kind or in two or more kinds. Moreover, the high-voltage insulating resin material of the present embodiment preferably does not substantially contain any polyamide resin other than the polyamide resin (A). "Substantially free" means that the content of polyamide resins other than the polyamide resin (A) is less than 1 mass%, preferably less than 0.1 mass%, and more preferably less than 0.01 mass%, relative to 100 mass% of the polyamide resin (A).

[0044] The high-voltage insulating resin material of this embodiment may contain components other than the polyamide resin and the polybutylene terephthalate resin (B). An example of the other component is a thermoplastic resin other than the polyamide resin and the polybutylene terephthalate resin (B). An example of the other component is a stabilizer. Examples of the stabilizer include a heat stabilizer, an antioxidant, and a component derived from a phosphorus atom-containing compound or a polymerization rate regulator that can be added during the synthesis of a polyamide resin. The total amount of the stabilizer is preferably 0.001 to 3 parts by mass per 100 parts by mass of the total of the polyamide resin (A) and the polybutylene terephthalate resin (B).

[0045] Examples of the antioxidant include phenol-based antioxidants (preferably hindered phenol-based antioxidants), amine-based antioxidants, phosphorus-based antioxidants, and sulfur-based antioxidants. These antioxidants can be used alone or in combination of two or more. The amount of the antioxidant added is preferably 0.001 to 3.0 parts by mass per 100 parts by mass of the total of the polyamide resin (A) and the polybutylene terephthalate resin (B).

[0046] In addition, examples of components other than the stabilizer include fillers, hydrolysis resistance improvers, matting agents, plasticizers, dispersants, antistatic agents, coloring inhibitors, gelling inhibitors, colorants, etc. For details of these, please refer to the descriptions in paragraphs 0130 to 0155 of Japanese Patent No. 4894982 and the descriptions in paragraphs 0041 and 0042, and paragraphs 0046 to 0103 of International Publication No. 2021 / 241471, the contents of which are incorporated herein by reference. The total amount of the other components is preferably 20% by mass or less, more preferably 10% by mass or less, even more preferably 5% by mass or less, and even more preferably 1% by mass or less of the high-voltage insulating resin material of this embodiment. Only one type of the other components may be used, or two or more types may be used in combination.

[0047] The high voltage insulating resin material of this embodiment is preferably excellent in tracking resistance under high voltage conditions. Specifically, the time until the insulating material breaks down at a voltage of 2000V according to the JIS-C2136 constant voltage tracking method (tracking resistance time at 2000V) is preferably 75 minutes or more, more preferably 80 minutes or more, even more preferably 85 minutes or more, and even more preferably 89 minutes or more. There is no particular upper limit for the tracking resistance time at 2000V of the insulating resin material, but 200 minutes or less is practical.

[0048] The high-voltage insulating resin material of the present embodiment is preferably used in applications where high voltage is applied, for example, in electric and electronic components such as chargers and connectors for high-speed charging. It is also preferably used as a covering material for cords and bus bars, and as a circuit board material. In addition to the above, the high voltage insulating resin material of this embodiment can also be used for the applications described in paragraph 0049 of JP 2020-076023 A, the contents of which are incorporated herein by reference.

[0049] The method for producing the high voltage insulating resin material in this embodiment is not limited, and a known method for producing insulating resin materials can be widely adopted, and includes a method in which the polyamide resin (A), the polybutylene terephthalate resin (B), and other components to be mixed as necessary are mixed in advance using various mixers such as a tumbler or a Henschel mixer, and then melt-kneaded using a mixer such as a Banbury mixer, a roll, a Brabender, a single-screw kneading extruder, a twin-screw kneading extruder, or a kneader. The temperature for melt-kneading is not particularly limited, but is usually in the range of 220 to 320°C.

[0050] The high-voltage insulating molded product of this embodiment is formed from the high-voltage insulating resin material of this embodiment. The method for forming the molded product is not particularly limited, and a conventionally known molding method can be adopted, for example, injection molding, injection compression molding, extrusion molding, profile extrusion, transfer molding, hollow molding, gas-assisted hollow molding, blow molding, extrusion blow molding, IMC (in-mold coating molding), rotational molding, multi-layer molding, two-color molding, insert molding, sandwich molding, foam molding, pressure molding, stretching, vacuum molding, etc. The high-voltage insulating resin material of this embodiment is preferably molded by injection molding. Examples of insulating molded products formed from the high voltage insulating resin material of this embodiment include injection molded products, thin-walled molded products, hollow molded products, films (including plate-shaped and sheet-shaped products), cylindrical shapes (hoses, tubes, etc.), annular shapes, circular shapes, elliptical shapes, gear shapes, polygonal shapes, irregular shapes, hollow products, frame-shaped, box-shaped, panel-shaped extrusion molded products, fibers, and the like, and injection molded products are preferred. The high-voltage insulating resin material of this embodiment can also be used as a surface layer material. For example, it can be attached to the surface of a conductive or weakly insulating film or sheet. The high-voltage insulating resin material of this embodiment can also be molded with other materials by insert molding.

[0051] The insulating resin material of the present embodiment can also be used as a fiber-reinforced resin material containing a filler, for example, pellets obtained by melt-kneading the insulating resin material of the present embodiment with glass fiber, and prepregs obtained by impregnating continuous fibers such as glass fiber with the insulating resin material of the present embodiment.

[0052] In addition, in this embodiment, by blending polyamide resin (A) with polybutylene terephthalate resin (B), the insulating properties (particularly, tracking resistance) of polybutylene terephthalate resin (B) at high withstand voltage can be improved, and therefore polyamide resin (A) can also be used as an agent for improving the tracking resistance of polybutylene terephthalate resin (B) under high pressure. EXAMPLES

[0053] The present invention will be described in more detail with reference to the following examples. The materials, amounts used, ratios, treatment details, treatment procedures, etc. shown in the following examples can be appropriately changed without departing from the spirit of the present invention. Therefore, the scope of the present invention is not limited to the specific examples shown below. When it is difficult to obtain the measuring instruments, etc. used in the examples due to obsolescence, etc., measurements can be made using other devices having equivalent performance.

[0054] Raw material <Synthesis of MXD6> In a jacketed reaction vessel equipped with a stirrer, a partial condenser, a cooler, a thermometer, a dropping tank, and a nitrogen gas inlet pipe, 7220 g (49.4 mol) of adipic acid (manufactured by BASF) and 11.7 g of sodium acetate / sodium hypophosphite monohydrate (molar ratio = 1 / 1.5) were charged, and after sufficient nitrogen substitution and heating to 170 °C to melt, while stirring the contents, 6661 g (48.9 mol) of metaxylylenediamine (manufactured by Mitsubishi Gas Chemical Company) was added dropwise to the melt in the reaction vessel with stirring, and while discharging the generated condensation water out of the system, the internal temperature was continuously raised to 250 °C over 2.5 hours. After the dropping was completed, the internal temperature was raised, and when it reached 260 °C, the inside of the reaction vessel was depressurized, and the melt polycondensation reaction was continued for another 20 minutes. Then, the system was pressurized with nitrogen, and the obtained polymer was taken out from the strand die and pelletized to obtain a polyamide resin. The conditioned moisture content of the obtained polyamide resin was 4.6%, the number average molecular weight was 15,000, the glass transition temperature was 85 °C, and the melting point was 237 °C.

[0055] PBT: Polybutylene terephthalate resin, manufactured by Mitsubishi Engineering Plastics Corporation, product number: Novaduran 5010R

[0056] Reference Example 1 <<Tracking resistance time>> After drying, polyamide resin MXD6 was injection molded at a cylinder temperature of melting point + 20 ° C to obtain a plate with a thickness of 6 mm. The obtained plate was cut into a size of 120 mm in length and 50 mm in width, sandwiched between glass plates, and held at 150 ° C for 1 hour under a nitrogen gas atmosphere to perform a crystallization treatment. The obtained plate was measured for the time until it broke at a voltage of 2000 V according to the JIS-C2136 constant voltage tracking method using an inclined flat plate tracking resistance tester YST-587 type (manufactured by Yamayo Test Instruments). It was determined that the plate broke when at least one of tracking breakdown, ignition, and penetration breakdown occurred, and the test was performed with n = 5, and the average time until it broke was taken as the tracking resistance time.

[0057] <<Flexural modulus>> After drying the polyamide resin MXD6, it was injection molded at a cylinder temperature of melting point + 20°C to obtain a test piece with a thickness of 4 mm. The obtained rectangular piece was sandwiched between glass plates and held at 150°C for 1 hour in a nitrogen gas atmosphere to carry out a crystallization treatment. The obtained test piece was stored at 23°C and 50% RH for 7 days, and then the flexural modulus (GPa) was determined according to JIS K 7171. The measurement was performed using a Bendgraph Type B (manufactured by Toyo Seiki Co., Ltd.) at a measurement temperature of 23° C. and a measurement humidity of 50% RH.

[0058] Reference example 2 In Reference Example 1, the resin was changed as shown in Table 1, but the rest was the same.

[0059] Example 1 The same procedures as in Reference Example 1 were carried out, except that the cylinder temperature during injection molding was changed to the melting point of MXD6 + 20°C.

[0060] [Table 1]

[0061] As is clear from the above results, the insulating resin material of this embodiment was excellent in high withstand voltage insulation properties and also in mechanical strength.

Claims

1. A high-voltage insulating resin material comprising 5 to 30 mass % of a polyamide resin (A) containing a structural unit represented by formula (X) and 95 to 70 mass % of a polybutylene terephthalate resin (B) (provided that the total of components (A) and (B) does not exceed 100 mass %). Formula (X) 【Chemistry 1】 (In formula (X), R １ ~R ８ each independently represents a hydrogen atom or an aliphatic group having 1 to 5 carbon atoms; Cy represents a benzene ring, a naphthalene ring, or a cyclohexane ring; n1 represents an integer of 0 to 2, and n2 represents 0 or 1; and ad represents an amide bond.

2. the polyamide resin (A) contains a diamine-derived structural unit and a dicarboxylic acid-derived structural unit, 2. The high-voltage insulating resin material according to claim 1, wherein 70 mol % or more of the diamine-derived structural units are structural units represented by formula (X).

3. the polyamide resin (A) contains a diamine-derived structural unit and a dicarboxylic acid-derived structural unit, 3. The high-voltage insulating resin material according to claim 1, wherein the diamine-derived structural unit comprises a diamine-derived structural unit represented by formula (Y): Formula (Y) 【Chemistry 2】 (In formula (Y), R １ ~R ８ each independently represents a hydrogen atom or an aliphatic group having 1 to 5 carbon atoms; and each n independently represents an integer of 0 to 2.

4. the polyamide resin (A) contains a diamine-derived structural unit and a dicarboxylic acid-derived structural unit, 3. The high-voltage insulating resin material according to claim 1, wherein the diamine-derived structural unit includes a xylylenediamine-derived structural unit.

5. the polyamide resin (A) contains a diamine-derived structural unit and a dicarboxylic acid-derived structural unit, 30 mol % or more of the dicarboxylic acid-derived structural units are structural units derived from an aliphatic dicarboxylic acid having 4 to 20 carbon atoms; 3. The high-voltage insulating resin material according to claim 1 or 2.

6. the polyamide resin (A) contains a diamine-derived structural unit and a dicarboxylic acid-derived structural unit, 3. The high-voltage insulating resin material according to claim 1, wherein the dicarboxylic acid-derived structural unit includes at least one of adipic acid, sebacic acid, and dodecanedioic acid.

7. the polyamide resin (A) contains a diamine-derived structural unit and a dicarboxylic acid-derived structural unit, 70 mol % or more of the diamine-derived structural units are xylylenediamine-derived structural units, 2. The high-voltage insulating resin material according to claim 1, wherein 70 mol % or more of the dicarboxylic acid-derived structural units are at least one of adipic acid, sebacic acid, and dodecanedioic acid.

8. 8. The high-voltage insulating resin material according to claim 1, wherein the insulating resin material has a time to breakdown at a voltage of 2000 V according to the JIS-C2136 constant voltage tracking method of 75 minutes or more.

9. 10. A high-voltage insulating molded product formed from the high-voltage insulating resin material according to claim 1, 2 or 7.

10. An agent for improving the tracking resistance of polybutylene terephthalate resin under high pressure, comprising a polyamide resin (A) containing a structural unit represented by formula (X): Formula (X) 【Transformation 3】 (In formula (X), R １ ~R ８ each independently represents a hydrogen atom or an aliphatic group having 1 to 5 carbon atoms; Cy represents a benzene ring, a naphthalene ring, or a cyclohexane ring; n1 represents an integer of 0 to 2, and n2 represents 0 or 1; and ad represents an amide bond.

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