Electric insulating resin composition

Abstract

To provide an electric insulating resin composition that allows simultaneous realization of flame retardancy and tracking resistance.SOLUTION: An electric insulating resin composition according to an embodiment comprises a polyalkylene terephthalate and a condensate of tetrabromobisphenol, cyanuric chloride, and tribromophenol. The amount of the condensate is 9-19 pts.mass relative to 100 pts.mass of the polyalkylene terephthalate.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to an electrical insulating resin composition. [Background technology]

[0002] Polyalkylene terephthalates, such as polybutylene terephthalate and polyethylene terephthalate, are widely used in fields such as electrical and electronic components due to their excellent physical properties, moldability, and mechanical characteristics. Because polyalkylene terephthalates themselves have poor flame retardancy, flame retardants are added when flame retardancy is required. While various compounds are used as flame retardants, the use of polymeric flame retardants has become increasingly desirable due to environmental and other considerations.

[0003] For example, Patent Document 1 discloses a flame-retardant resin composition in which a thermoplastic polyester resin such as polybutylene terephthalate is blended with a halogen-containing polyhydroxypolyether resin as a flame retardant obtained by reacting a tetrabromobisphenol A-epichlorohydrin epoxy resin with tetrabromobisphenol A, and antimony trioxide as a flame retardant aid. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Special Publication No. 8-26228 [Patent Document 2] Special Publication No. 60-4236 Summary of the Invention [Problem to be solved by the invention]

[0005] As mentioned above, adding a flame retardant to polyalkylene terephthalate can impart flame retardancy, but adding a flame retardant has the problem of reducing electrical insulation, particularly tracking resistance. Here, tracking resistance refers to resistance to tracking. Tracking refers to the formation of conductive paths (tracks) on the surface of an insulator, leading to short circuits (dielectric breakdown) between wirings.

[0006] An object of an embodiment of the present invention is to provide an electrical insulating resin composition that can achieve both flame retardancy and tracking resistance. [Means for solving the problem]

[0007] The present invention includes the embodiments shown below. [1] Polyalkylene terephthalate; a condensation product of tetrabromobisphenol, cyanuric chloride and tribromophenol, The electrical insulating resin composition comprises the condensate in an amount of 9 to 19 parts by mass per 100 parts by mass of the polyalkylene terephthalate. [2] The condensate contains a compound represented by the following general formula (1): [ka] R in formula (1) 1 represents -C(CH3)2- or -SO2-, and n represents a number of 1 or more. [1] The electrically insulating resin composition according to [1]. [3] The electrically insulating resin composition according to [1] or [2], further comprising one or more flame retardant auxiliaries selected from the group consisting of antimony trioxide, antimony pentoxide, sodium antimonate, potassium antimonate, zinc stannate, and zinc borate. [4] The electrically insulating resin composition according to [3], wherein the amount of the flame retardant aid is 1 to 100 parts by mass per 100 parts by mass of the condensate. [5] The electrically insulating resin composition according to any one of [1] to [4], wherein the polyalkylene terephthalate comprises polybutylene terephthalate. [6] Use of a resin composition for electrical insulation, comprising a polyalkylene terephthalate and a condensate of tetrabromobisphenol, cyanuric chloride, and tribromophenol, wherein the amount of the condensate is 9 to 19 parts by mass per 100 parts by mass of the polyalkylene terephthalate. [Effects of the Invention]

[0008] The electrical insulating resin composition according to the embodiment of the present invention can achieve both flame retardancy and tracking resistance. DETAILED DESCRIPTION OF THE INVENTION

[0009] The electrical insulating resin composition according to the present embodiment contains a polyalkylene terephthalate and a condensate of tetrabromobisphenol, cyanuric chloride, and tribromophenol, and the amount of the condensate is 9 to 19 parts by mass per 100 parts by mass of the polyalkylene terephthalate. According to this embodiment, high flame retardancy can be achieved and high tracking resistance can be obtained simply by adding a small amount of the condensate, which serves as a flame retardant. Therefore, both flame retardancy and tracking resistance can be achieved. Furthermore, while it is generally difficult to achieve a V-0 rating in a thin molded article in the UL-94 test, this embodiment makes it possible to achieve a V-0 rating even in a thin molded article. Furthermore, because only a small amount of the condensate, which serves as a flame retardant, is added, the inherent resin properties of the polyalkylene terephthalate can be easily maintained at a high level.

[0010] Polyalkylene terephthalate is a polyester resin obtained by polycondensation reaction of terephthalic acid and an aliphatic diol, such as ethylene glycol, propylene glycol, or butylene glycol.

[0011] Specific examples of polyalkylene terephthalate include polyethylene terephthalate, polypropylene terephthalate, and polybutylene terephthalate. Among these, polybutylene terephthalate (PBT) is preferred. That is, in one embodiment, the polyalkylene terephthalate preferably contains polybutylene terephthalate. In this case, the amount of polybutylene terephthalate is preferably 50% by mass or more, more preferably 70% by mass or more, and even more preferably 90% by mass or more, based on 100% by mass of the polyalkylene terephthalate, and may be 100% by mass.

[0012] In this embodiment, a condensate of tetrabromobisphenol, cyanuric chloride, and tribromophenol is used as the flame retardant. The condensate is formed by dehydrochlorination condensation between cyanuric chloride and tetrabromobisphenol and between cyanuric chloride and tribromophenol.

[0013] Examples of tetrabromobisphenol include tetrabromobisphenol A and tetrabromobisphenol S.

[0014] In one embodiment, the condensate is a condensate of tetrabromobisphenol A and / or tetrabromobisphenol S, cyanuric chloride, and tribromophenol, and preferably contains a compound (1) represented by the following general formula (1): [ka]

[0015] R in formula (1) 1 represents -C(CH3)2- or -SO2-, preferably -C(CH3)2-. In formula (1), n ​​is the average number of repeating units and is a number of 1 or more. n is preferably 1 to 5, more preferably 1.8 to 4, and even more preferably 2 or more and less than 3. Here, n is calculated from the weight average molecular weight of compound (1).

[0016] When the condensate contains compound (1), it is preferable that compound (1) is the main component, and the amount of compound (1) in 100% by mass of the condensate is preferably 80% by mass or more, more preferably 90% by mass or more, even more preferably 95% by mass or more, and may be 100% by mass.

[0017] The condensate can be obtained, for example, by treating tetrabromobisphenol A and / or tetrabromobisphenol S, cyanuric chloride, and tribromophenol with an alkali. In one embodiment, the condensate can be produced by the method described in Japanese Patent Publication No. 60-4236, by treating a mole of tetrabromobisphenol A and / or tetrabromobisphenol S and (3-2a) moles of tribromophenol with 3 or more equivalents of alkali in a solvent, relative to 1 mole of cyanuric chloride. Here, a is greater than 0 and less than 1.5, preferably 0.5 or greater and less than 1.

[0018] The weight average molecular weight (Mw) of the condensate is preferably 2000 to 6000, more preferably 2000 to 5000, more preferably 2200 to 4000, and even more preferably 2500 to 3500. By using a condensate having a relatively small molecular weight in this way, the fluidity of the resin composition is increased, making it easier to thin the wall of a molded article.

[0019] In this specification, the weight-average molecular weight is a value measured by GPC (gel permeation chromatography) and calculated using a calibration curve based on standard polystyrene. Specifically, a tetrahydrofuran (THF) solution with a sample concentration of 0.2% by mass is prepared and filtered through a membrane filter (0.45 μm) to obtain a measurement solution. Using the following measurement device and column, molecular weight measurements are carried out using THF as the eluent, at a column temperature of 40°C, a sample injection volume of 20 μL, and a flow rate of 1.0 mL / min, and the weight-average molecular weight can be calculated using the calibration curve based on standard polystyrene. Measuring device: Prominance-I (Shimadzu Corporation) Columns: TSKgel G2000Hxl, TSKgel G3000Hxl, and TSKgel G4000Hxl (manufactured by Shimadzu Corporation) connected in series.

[0020] The amount of the condensate in the electrical insulating resin composition is 9 to 19 parts by mass, preferably 12 to 19 parts by mass, more preferably 15 to 19 parts by mass, and even more preferably 17 to 18 parts by mass, per 100 parts by mass of polyalkylene terephthalate.

[0021] The electrical insulating resin composition may further contain a flame retardant aid. The flame retardant aid is preferably one or more selected from the group consisting of antimony trioxide, antimony pentoxide, sodium antimonate, potassium antimonate, zinc stannate, and zinc borate. The inclusion of such a flame retardant aid can further improve flame retardancy. The flame retardant aid is more preferably one or more selected from the group consisting of antimony trioxide, antimony pentoxide, sodium antimonate, and potassium antimonate, and even more preferably antimony trioxide and / or antimony pentoxide.

[0022] The amount of the flame retardant aid is preferably 1 to 100 parts by mass, more preferably 5 to 80 parts by mass, more preferably 10 to 60 parts by mass, and even more preferably 20 to 50 parts by mass, relative to 100 parts by mass of the condensate.

[0023] The insulating resin composition may further contain a fibrous reinforcing material. By containing the fibrous reinforcing material, the strength of the molded article can be improved. Examples of the fibrous reinforcing material include glass fiber and carbon fiber.

[0024] When a fibrous reinforcing material is added, the amount is not particularly limited, but may be, for example, 1 to 100 parts by mass, 5 to 80 parts by mass, or 10 to 60 parts by mass per 100 parts by mass of polyalkylene terephthalate.

[0025] The electrical insulating resin composition may further contain an inorganic filler. Examples of inorganic fillers include metal silicates and titanium oxide. Examples of metal silicates include magnesium silicate-based fillers such as talc, aluminum silicate-based fillers such as kaolin, aluminum-potassium silicate-based fillers such as mica, and calcium silicate-based fillers such as wollastonite. Among these, adding a metal silicate can enhance the effect of improving tracking resistance.

[0026] When an inorganic filler (more preferably a metal silicate) is added, the amount is not particularly limited, but may be, for example, 1 to 100 parts by mass, 5 to 80 parts by mass, or 10 to 60 parts by mass per 100 parts by mass of polyalkylene terephthalate.

[0027] The electrical insulating resin composition may further contain various additives such as an antioxidant, an anti-dripping agent, an ultraviolet absorber, a crystal nucleating agent, a crystallization accelerator, and a colorant (for example, a pigment).

[0028] Examples of antioxidants include phenol-based antioxidants, phosphite-based antioxidants, thioether-based antioxidants, etc. When an antioxidant is contained, the amount thereof is not particularly limited, and may be, for example, 0.05 to 5 parts by mass or 0.1 to 3 parts by mass relative to 100 parts by mass of the polyalkylene terephthalate.

[0029] Examples of the anti-dripping agent include polytetrafluoroethylene (PTFE). When an anti-dripping agent is contained, the amount thereof is not particularly limited, and may be, for example, 0.05 to 5 parts by mass or 0.1 to 3 parts by mass per 100 parts by mass of polyalkylene terephthalate.

[0030] The method for preparing the resin composition for electrical insulation is not particularly limited, and examples thereof include a method in which a polyalkylene terephthalate and the condensate, and further optional components such as a flame retardant aid, a fibrous reinforcing material, an inorganic filler, and other additives are blended and melt-mixed using a mixer such as an extruder.

[0031] The obtained electrical insulating resin composition can be molded as desired by any molding method such as injection molding, extrusion molding, vacuum molding, etc., to obtain a molded product.

[0032] The resin composition according to this embodiment can be used for various electrical insulation applications. That is, a molded article produced from the resin composition according to this embodiment has excellent flame retardancy and tracking resistance, and therefore can be preferably used for, for example, voltage-resistant parts used as electrical and electronic parts and automotive parts, such as sockets, coils, terminal blocks, plugs, switches, relay parts, and breaker parts. Therefore, the resin composition according to this embodiment is also referred to as a resin composition for voltage-resistant parts.

[0033] As described above, the electrical insulating resin composition according to this embodiment can exhibit flame retardancy even when molded into a thin shape, and is therefore suitable for use in producing a thin molded article having a thickness of, for example, 0.4 to 1.6 mm, more preferably 0.5 to 1.0 mm, and even more preferably less than 1.0 mm.Even in such a thin molded article, both flame retardancy and tracking resistance can be achieved. [Example]

[0034] Examples will be described in detail below along with comparative examples, but the present invention is not limited to these examples.

[0035] Details of the raw materials used in the examples and comparative examples are as follows. [Flame retardant] Flame retardant 1: a compound represented by the above formula (1) (wherein R 1 Tetrabromobisphenol A, cyanuric chloride, and tribromophenol condensate (TBBA / CC / TBP), containing -C(CH3)2-. The synthesis method is as follows:

[0036] A 5 L glass four-neck flask equipped with a reflux condenser, thermometer, dropping funnel, and stirrer was charged with 543.9 g (1.0 mol) of tetrabromobisphenol A (TBBA), 661.6 g (2.0 mol) of tribromophenol (TBP), 245.3 g (1.33 mol) of cyanuric chloride (CC), and 2 L of methylene chloride. The mixture was cooled to 5°C with stirring, and 352.0 g of a 50% by weight aqueous NaOH solution was slowly added dropwise from the dropping funnel while maintaining the reaction solution temperature below 10°C. After the addition was complete, the temperature was maintained below 10°C for 30 minutes, then increased at a rate of 10°C / h until the solution reached reflux. After maintaining the reflux temperature for 3 hours, the reaction solution was washed with water and reprecipitated in 2 L of methanol. The resulting precipitate was then washed sequentially with 1 N hydrochloric acid, 1 L of water, and 2 L of methanol. After drying at 80°C for 12 hours, a white powder was obtained in a yield of 98% by mass, and the bromine content of the powder was 60.0% by mass. The weight average molecular weight (Mw) of the powder measured by GPC in a THF solution was 3000. The chemical reaction formula is as follows:

[0037] [ka]

[0038] Flame retardant 2: Comparative example, "SR-T20000" manufactured by Sakamoto Pharmaceutical Co., Ltd., brominated bisphenol A epoxy resin, bromine content 52% by mass

[0039] Flame retardant 3: Comparative example, "SAYTEX HP-7010" manufactured by Albemarle, brominated polystyrene, bromine content 68% by mass

[0040] Flame retardant 4: Comparative example, "Pyroguard (registered trademark) SR-460B" manufactured by Daiichi Kogyo Seiyaku Co., Ltd., tribromophenol polycondensate, bromine content 62% by mass

[0041] [Polyalkylene terephthalate] PBT (GF30%): "Toraycon 1101G-30" manufactured by Toray Industries, Inc., a glass fiber reinforced polybutylene terephthalate containing 30% glass fiber by mass. The figures in parentheses in the table indicate the amount of glass fiber blended, and the remainder indicates the amount of PBT blended.

[0042] [Flame retardant synergist] Flame retardant aid 1: antimony trioxide, "Pyroguard (registered trademark) AN-800T" manufactured by Daiichi Kogyo Seiyaku Co., Ltd. Flame retardant synergist 2: Antimony pentoxide, Nissan Chemical Co., Ltd. "NA-1030"

[0043] [Metal silicates] Metal silicate: talc, Hayashi Kasei Micron White #5000S

[0044] [Additives] Stabilizer 1: Hindered phenol antioxidant, "Irganox 1010" manufactured by BASF Japan Ltd. Stabilizer 2: Phosphite antioxidant, "Irgafos 168" manufactured by BASF Japan Ltd. Anti-drip agent: AGC FluonPTFE CD145E (PTFE)

[0045] [Evaluation method] Flame retardancy: Measured in accordance with UL-94 using rectangular test specimens (127mm long x 12.7mm wide x 0.8mm thick). Flame retardancy was evaluated according to the UL-94 criteria using a four-point scale: V-0 (excellent), V-1 (good), V-2 (passable), and NR (fail). V-2 or higher is acceptable, while NR is outside the UL-94 criteria and indicates poor flame retardancy.

[0046] Tracking resistance: Comparative tracking index (CTI) was measured using a square plate test piece (50mm x 50mm x 3.2mm thick) in accordance with IEC 60112 of the International Electrotechnical Commission. The CTI was determined as the voltage that could be withstood by dropping 50 drops of electrolyte A between the electrodes on the surface of the square plate test piece without tracking. Those with a CTI of 600V or more were rated as "A" (very good tracking resistance), those with a CTI of 250V or more but less than 600V were rated as "B" (good tracking resistance), and those with a CTI of less than 250V were rated as "C" (poor tracking resistance).

[0047] [First Experimental Example] According to the formulation (parts by mass) shown in Table 1 below, pellets were produced by extrusion using a twin-screw extruder at 260°C and a screw rotation speed of 200 rpm. These pellets were injection molded under conditions of a cylinder temperature of 260°C and a mold temperature of 80°C to produce test specimens. The obtained test specimens were used to evaluate flame retardancy and tracking resistance.

[0048] [Table 1]

[0049] The results are shown in Table 1. In the first experimental example, for each of flame retardants 1 to 4, the minimum amount of flame retardant required to achieve a flame retardancy rating of V-0 was determined in a preliminary test, and in each example and comparative example, the amount of flame retardant was set to that minimum amount, and it was evaluated whether or not a difference in tracking resistance would occur in that case. As a result, Examples 1 to 3, which used flame retardant 1 (TBBA / CC / TBP) according to this embodiment, had excellent tracking resistance. In contrast, Comparative Examples 1 to 3, which used polymeric flame retardants 2 to 4 different from the flame retardant according to this embodiment, had poor tracking resistance.

[0050] [Second Experimental Example] Test specimens were prepared in the same manner as in Experimental Example 1, according to the formulation (parts by mass) shown in Table 2 below, and the flame retardancy and tracking resistance were evaluated using the test specimens obtained. Example 1 in Table 2 corresponds to Example 1 of Experimental Example 1.

[0051] [Table 2]

[0052] The results are shown in Table 2. In the second experimental example, in Comparative Examples 4 to 6, the blending amount of the flame retardant was the same as in Example 1, and it was confirmed whether the effect of achieving both flame retardancy and tracking resistance could be achieved. In Comparative Examples 4 and 5, the amount of flame retardant was reduced compared to Comparative Examples 1 and 2, but the tracking resistance was still poor, and the flame retardancy was also reduced compared to Example 1. In Comparative Example 6, like Comparative Example 3, the flame retardancy was excellent but the tracking resistance was poor. Thus, when flame retardants 2 to 4 different from the flame retardant according to this embodiment were used, it was not possible to achieve both flame retardancy and tracking resistance.

[0053] In the second experimental example, Examples 4 to 7 and Comparative Example 7 were evaluated by varying the blending amount of the flame retardant according to the present embodiment. As a result, Example 4, in which the amount of flame retardant 1 was increased relative to Example 1 to 19 parts by mass relative to 100 parts by mass of PBT, exhibited excellent flame retardancy and good tracking resistance, similar to Example 1. Examples 5 to 7, in which the amount of flame retardant 1 was reduced relative to Example 1 to 9 to 14.3 parts by mass relative to 100 parts by mass of PBT, exhibited lower flame retardancy compared to Example 1, but were still at the acceptable level of V-2 and had good tracking resistance. In contrast, Comparative Example 7, in which the amount of flame retardant 1 was increased to 21 parts by mass relative to 100 parts by mass of PBT, exhibited excellent flame retardancy but poor tracking resistance, failing to achieve both flame retardancy and tracking resistance.

[0054] [Third Experimental Example] Test specimens were prepared in accordance with the formulation (parts by mass) shown in Table 3 below, except for the same procedures as in Experimental Example 1, and the flame retardancy and tracking resistance were evaluated using the obtained test specimens. Example 1 in Table 3 corresponds to Example 1 of Experimental Example 1.

[0055] [Table 3]

[0056] The results are shown in Table 3. In Example 8, by adding a metal silicate, it was possible to improve the tracking resistance compared to Example 1 while maintaining excellent flame retardancy.

[0057] The various numerical ranges described in this specification can be arbitrarily combined with their respective upper and lower limit values, and all such combinations are considered to be preferred numerical ranges described in this specification. Furthermore, a numerical range described as "X to Y" means from X to Y.

[0058] Although several embodiments of the present invention have been described above, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their omissions, substitutions, modifications, etc. are included within the scope and spirit of the invention, as well as within the scope of the invention described in the claims and their equivalents.

Claims

1. polyalkylene terephthalate, a condensation product of tetrabromobisphenol, cyanuric chloride and tribromophenol, The amount of the condensate per 100 parts by mass of the polyalkylene terephthalate is 9 to 19 parts by mass.

2. The condensate contains a compound represented by the following general formula (1): 【Chemical 1】 R in formula (1) １ is -C(CH ３ ) ２ -or-SO ２ The electrically insulating resin composition according to claim 1, wherein n represents - and n represents a number of 1 or more.

3. 3. The electrically insulating resin composition according to claim 1, further comprising one or more flame retardant aids selected from the group consisting of antimony trioxide, antimony pentoxide, sodium antimonate, potassium antimonate, zinc stannate, and zinc borate.

4. 4. The electrically insulating resin composition according to claim 3, wherein the amount of the flame retardant aid is 1 to 100 parts by mass per 100 parts by mass of the condensate.

5. The electrically insulating resin composition according to claim 1 or 2, wherein the polyalkylene terephthalate comprises polybutylene terephthalate.

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