Flame-retardant thermoplastic resin composition and molded article made therefrom

Abstract

To provide a thermoplastic resin composition that can produce molded articles with excellent extrusion moldability, flexibility, flame retardancy, and dielectric breakdown properties. [Solution] A thermoplastic resin composition comprising (A) 100 parts by mass of polybutylene (terephthalate / dodecadioate) copolymer having a melt mass flow rate of 3.0 g / 10 min or less, measured at a temperature of 250°C and a load of 1000 g in accordance with ISO 1133, (B) 10 to 20 parts by mass of a flame retardant having a benzene ring in its side chain, and (C) 3 to 8 parts by mass of an antimony compound.

Description

Technical Field

[0001] The present invention relates to a thermoplastic resin composition having excellent flexibility, high flame retardancy, and dielectric breakdown characteristics, and a molded product formed by molding the same.

Background Art

[0002] Polybutylene terephthalate resin (hereinafter sometimes abbreviated as PBT resin) is widely used in various applications such as automotive parts, electrical and electronic parts, mechanical parts, and daily necessities because it has excellent electrical properties, chemical resistance, heat resistance, and dimensional stability.

[0003] In recent years, the demand for higher withstand voltage of industrial molded products has been increasing. Especially with the improvement of EV output in the future, in automotive parts, the utilization of PBT resin with higher heat resistance than polyamide 11 and polyamide 12 is expected. In addition, with the increase in the voltage of automotive parts, the products are also getting longer. Since it is difficult to put existing injection molded products and powder coated products into a constant temperature bath during curing, products that can be extrusion processed into insulating coating materials are desired.

[0004] On the other hand, since PBT resin is inherently flammable, when used as an industrial material such as the above-mentioned mechanical and mechanical parts, electrical and electronic parts, and automotive parts, in addition to the balance of general chemical and physical properties, safety against fire, that is, flame retardancy is required, and in many cases, a high degree of flame retardancy showing V-0 of the UL-94 standard is required.

[0005] Due to the above needs, there are applications that require a material with excellent flexibility that can be extruded or bent, high flame retardancy, and dielectric breakdown characteristics.

[0006] For example, Patent Document 1 exemplifies a method of imparting flexibility that enables extrusion molding by replacing a part of the PBT resin with other components. Further, Patent Documents 2 and 3 exemplify methods of adding a flame retardant to a copolyester resin to impart flexibility and flame retardancy. Furthermore, Patent Document 4 exemplifies a method of adding an elastomer to a PBT resin to impart flexibility.

Prior Art Documents

Patent Documents

[0007]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Summary of the Invention

Problems to be Solved by the Invention

[0008] However, the polyester resin composition described in Patent Document 1 does not have the flame retardancy required for industrial materials. In the method of adding a flame retardant having a carboxylic acid in the main chain described in Patent Document 2, sufficient dielectric breakdown characteristics cannot be exhibited. Further, in the copolyester resin described in Patent Document 3, due to the low intrinsic viscosity, the resin was likely to draw down at the die outlet and the extrusion moldability was insufficient. In the method of adding an elastomer described in Patent Document 4, sufficient flexibility was not imparted, and when a large amount of elastomer was added to impart flexibility, the combustibility decreased.

[0009] In view of the above problems, an object of the present invention is to provide a thermoplastic resin composition having excellent flexibility enabling extrusion molding, high flame retardancy and dielectric breakdown characteristics by increasing the intrinsic viscosity by solid-phase polymerization of a copolyester resin and adding a specific flame retardant. [Means for solving the problem]

[0010] To solve the above problems, the present invention has the following configuration. (1) A thermoplastic resin composition comprising (A) 100 parts by mass of polybutylene (terephthalate / dodecadioate) copolymer having a melt mass flow rate of 3.0 g / 10 min or less, measured at a temperature of 250°C and a load of 1000 g in accordance with ISO 1133, (B) 10 to 20 parts by mass of a flame retardant having a benzene ring in its side chain, and (C) 3 to 9 parts by mass of an antimony compound. (2) The thermoplastic resin composition according to (1), further comprising 100 parts by mass of polybutylene (terephthalate / dodecadioate) copolymer, wherein the melt mass flow rate value measured at a temperature of 250°C and a load of 1000g in accordance with (A) ISO1133 is 3.0g / 10min or less, and further comprising 0.3 to 10.0 parts by mass of (D) dicyclopentadiene type epoxy resin. (3) The thermoplastic resin composition according to (1) or (2), wherein the flexural modulus measured in accordance with ISO 178 is less than 1.00 GPa and the tensile strain measured according to ISO 527 is 100% or more. (4) The thermoplastic resin composition according to (1) to (3), wherein the dielectric breakdown voltage when measured on a 3 mm square plate is 50 kV or more. (5) The thermoplastic resin composition according to (1) to (4), wherein the melt mass flow rate value measured at a temperature of 250°C and a load of 1000g in accordance with ISO1133 is 10.0g / 10min or less. (6) A molded article comprising the flame-retardant thermoplastic resin composition described in either (1) or (5). (7) An extruded article obtained by extruding a flame-retardant thermoplastic resin composition according to either (1) or (6). [Effects of the Invention]

[0011] This invention, by compounding polybutylene (terephthalate / dodecadioate) resin with polypentabromobenzyl acrylate and antimony trioxide, provides excellent flexibility for extrusion molding, high flame retardancy, and dielectric breakdown properties, making it useful for long electrical and electronic components and automotive parts subjected to high voltage. [Modes for carrying out the invention]

[0012] The thermoplastic resin composition of the present invention will be described in detail.

[0013] The thermoplastic resin composition of the present invention comprises (A) 100 parts by mass of polybutylene (terephthalate / dodecadioate) copolymer having a melt mass flow rate of 3.0 g / 10 min or less, measured at a temperature of 250°C and a load of 1000 g in accordance with ISO 1133, (B) 10 to 20 parts by mass of a flame retardant having a benzene ring in its side chain, and (C) 3 to 9 parts by mass of an antimony compound.

[0014] The polybutylene (terephthalate / dodecanediote) copolymer used in the present invention (A), which has a melt mass flow rate of 3.0 g / 10 min or less measured at a temperature of 250°C and a load of 1000 g in accordance with ISO 1133 (hereinafter sometimes abbreviated as (A) (polybutylene (terephthalate / dodecanediote) copolymer) is a copolymer of terephthalic acid and dodecanedionic acid and 1,4-butanediol, obtained by polycondensation of terephthalic acid or its ester-forming derivative, and dodecanedionic acid or its ester-forming derivative, with butanediol or its ester-forming derivative by commonly known methods. Further copolymerization of other components is also possible.

[0015] Other copolymerization components include dicarboxylic acids other than terephthalic acid and dodecanoic acid or their ester-forming derivatives, and diols other than butanediol. Examples of dicarboxylic acids or their ester-forming derivatives include isophthalic acid, naphthalenedicarboxylic acid, cyclohexanedicarboxylic acid, 4,4'-diphenoxyethanedicarboxylic acid, adipic acid, sebacic acid, and their alkyl esters. Examples of diols include 1,2-butanediol, 1,3-butanediol, 2,3-butanediol, 2-methyl-1,3-propanediol, trimethylene glycol, propylene glycol, hexamethylene glycol, polyethylene glycol, polypropylene glycol, and polytetramethylene glycol.

[0016] The dodecanedionic acid content (hereinafter referred to as the dodecanedionic acid content) in the total dicarboxylic acid components constituting the (A)(polybutylene (terephthalate / dodecadioate) copolymer of the present invention) is preferably 5 to 20 mol%. The dodecanedionic acid component refers to the residues of dodecanedionic acid or its ester-forming derivatives that constitute the polybutylene terephthalate resin. By incorporating the dodecanedionic acid component as the dicarboxylic acid component, the solidification rate of the polybutylene (terephthalate / dodecadioate) copolymer is slowed down, and the molecular mobility is improved, making it more flexible, which enables extrusion molding and improves bendability. When the dodecanedionic acid content is 5 mol% or more, the extrusion moldability is improved, and 10 mol% is more preferable. When it is 20 mol% or less, the rigidity of the molded product is improved, and 15 mol% is more preferable.

[0017] The method for producing the (A) polybutylene (terephthalate / dodecanoate) copolymer used in the present invention is not particularly limited, and known polycondensation methods, ring-opening polymerization methods, etc. can be mentioned. Either a batch polymerization method or a continuous polymerization method may be used, and either a polycondensation reaction by transesterification or direct polymerization can be applied. In terms of being able to reduce the amount of carboxyl end groups, the continuous polymerization method is preferred, and in terms of cost, the direct polymerization method is preferred.

[0018] In addition, in order to effectively advance the esterification reaction, transesterification reaction, and polycondensation reaction, it is preferable to add a catalyst during these reactions. Specific examples of the catalyst include organic titanium compounds, tin compounds, zirconia compounds, antimony compounds, etc. Two or more of these may be used. Among these, organic titanium compounds and tin compounds are preferred. Among the organic titanium compounds, tetra-n-propyl ester, tetra-n-butyl ester, and tetraisopropyl ester of titanic acid are more preferred, and tetra-n-butyl ester of titanic acid is particularly preferred. Among the tin compounds, dibutyltin oxide, methylphenyltin oxide, and tetraethyltin are preferred. The addition amount of the catalyst is preferably in the range of 0.005 to 0.5 parts by mass, more preferably in the range of 0.01 to 0.2 parts by mass, based on 100 parts by mass of the (A) polybutylene (terephthalate / dodecanoate) copolymer, in terms of mechanical properties, moldability, and color tone.

[0019] The (A) polybutylene (terephthalate / dodecanedioate) copolymer used in the present invention has a melt mass flow rate value (MFR value) measured at a temperature of 250 °C and a load of 1000 g in accordance with ISO 1133 of 3.0 g / 10 min or less. If it is 3.0 g / 10 min or more, the viscosity of the thermoplastic resin composition decreases, it is liable to draw down, and the extrusion moldability deteriorates. More preferably, it is 2.0 g / 10 min or less. The (A) polybutylene (terephthalate / dodecanedioate) copolymer preferably has a melt mass flow rate value (MFR value) measured at a temperature of 250 °C and a load of 1000 g in accordance with ISO 1133 of 0.01 g / 10 min or more. If it is 0.01 g / 10 min or more, it is preferable in terms of good fluidity during extrusion.

[0020] As a means for making the MFR value of the (A) polybutylene (terephthalate / dodecanedioate) copolymer of the present invention fall within the above range, it can be obtained by subjecting the polybutylene (terephthalate / dodecanedioate) copolymer to solid-phase polymerization at a more appropriate temperature and time.

[0021] The relative viscosity at 25 °C measured with a 0.5 mass% orthochlorophenol solution of the (A) polybutylene (terephthalate / dodecanedioate) copolymer used in the present invention is preferably 1.85 or more. The relative viscosity is the ratio of the polymer solution viscosity to the solvent viscosity (η

[0022] , , =η / η0), and the efflux time (t) of the polybutylene (terephthalate / dodecanedioate) copolymer solution and the efflux time (t0) of the solvent are measured using an Ubbelohde viscometer and calculated from equation (1). η r =η / η0=t / t0 ···(1)

[0022] When the relative viscosity measured by this method is 1.85 or higher, drawdown is suppressed and extrudeability is good, and it is more preferably 1.9 or higher. When it is 7.0 or lower, it is preferable in that it has good fluidity during extrusion molding, and it is more preferably 5.0 or lower. By adjusting the temperature and reaction time during polybutylene (terephthalate / dodecanediote) copolymerization, a (A) polybutylene (terephthalate / dodecanediote) copolymer with a relative viscosity of 1.85 or higher can be obtained.

[0023] (A) The polybutylene (terephthalate / dodecanediote) copolymer preferably has one endothermic peak observed when heated from 40°C to 300°C at a rate of 20°C / min under a nitrogen atmosphere using a differential scanning calorimeter (DSC), and its endothermic peak temperature (melting point) is preferably in the range of 200 to 220°C. In terms of heat resistance as a molded article, a melting point of 200°C or higher is preferable, and 220°C or higher is more preferable. A melting point of 220°C or lower is preferable because it eliminates the need to melt at a higher temperature during extrusion molding, suppresses drawdown, and further improves shapeability, and 210°C or lower is more preferable. (A) By setting the dodecanedionic acid content in the total dicarboxylic acid components constituting the polybutylene (terephthalate / dodecanediote) copolymer to the range of 5 to 20 mol%, a polybutylene (terephthalate / dodecanediote) copolymer with an endothermic peak temperature of 200 to 220°C can be obtained.

[0024] When polybutylene (terephthalate / dodecanediote) copolymer is used, the inclusion of dodecanedionic acid improves molecular mobility, resulting in better flexibility and tensile strain of the thermoplastic resin composition.

[0025] (A) The polybutylene (terephthalate / dodecanediote) copolymer preferably has a carboxyl terminal group concentration of 30 equivalents / t or less. A carboxyl terminal group concentration of 30 equivalents / t or less provides excellent heat and humidity resistance when molded into a product. More preferably, it is 25 equivalents / t or less. The lower limit of the carboxyl group concentration is 0 eq / t. Here, the carboxyl group concentration of (A) polybutylene (terephthalate / dodecanediote) copolymer is the value obtained by dissolving the (A) polybutylene (terephthalate / dodecanediote) copolymer in 50 mL of a mixed solution of o-cresol / chloroform (2 / 1 vol / vol), and titrating the solution with 0.05 mol / L ethanolic potassium hydroxide using 1% bromophenol blue as an indicator.

[0026] In terms of extrusion moldability after the addition of flame retardants and the like, the thermoplastic resin composition of the present invention preferably has a melt mass flow rate (MFR value) of 10.0 g / 10 min or less, measured in accordance with ISO 1133 at a temperature of 250°C and a load of 1000 g, which allows for extrusion molding without drawdown. More preferably, it is 8.0 g / 10 min or less. A melt mass flow rate (MFR value) of 1.0 g / 10 min or more is preferable in that it provides good fluidity during extrusion molding. More preferably, it is 2.0 g / 10 min or more.

[0027] As a means of making the MFR value of the thermoplastic resin composition of the present invention within the above range, it is preferable to use (A) a polybutylene (terephthalate / dodecanediote) copolymer having an MFR value of 3.0 g / 10 min or less, measured at a temperature of 250°C and a load of 1000 g in accordance with ISO 1133, and (B) a flame retardant having a benzene ring in the side chain that can suppress thermal decomposition during combustion without impairing flexibility and impart flame retardancy.

[0028] (B) An example of a flame retardant having a benzene ring in the side chain is polypentabromobenzyl acrylate. When using a flame retardant that does not have a benzene ring in the side chain, such as a flame retardant with a benzene ring in the main chain, for example, brominated polycarbonate or brominated epoxy, the dielectric breakdown properties tend to decrease because it easily forms electrical pathways. Furthermore, when using flame retardants such as brominated polycarbonate or brominated epoxy, flexibility, i.e., the flexural modulus, also decreases. In addition, (B) a flame retardant having a benzene ring in the side chain can suppress thermal decomposition during combustion and impart flame retardancy without impairing the flexibility of the (A) polybutylene (terephthalate / dodecanediote) copolymer.

[0029] The weight-average molecular weight (Mw) of the flame retardant having a benzene ring in its side chain (B) used in the present invention is not particularly limited, but is preferably 10,000 to 100,000. By setting the weight-average molecular weight (Mw) of the flame retardant having a benzene ring in its side chain (B) to 10,000 or more, the amount of gas generated during molding of the thermoplastic resin composition can be suppressed, thereby suppressing defects in the appearance of the molded product and mold contamination. Furthermore, by setting it to 100,000 or less, good moldability of the thermoplastic resin composition can be maintained. More preferably, it is 20,000 to 50,000. The weight-average molecular weight (Mw) is determined as a value on a standard polystyrene basis by gel permeation chromatography (GPC).

[0030] A preferred polypentabromobenzyl acrylate is, for example, FR-1025 (trade name) manufactured by ICL.

[0031] The amount of (B) a flame retardant having a benzene ring in its side chain in the thermoplastic resin composition of the present invention is 10 to 20 parts by mass per 100 parts by mass of the (A) polybutylene (terephthalate / dodecanediote) copolymer. If the amount of (B) a flame retardant having a benzene ring in its side chain is less than 10 parts by mass, the flame retardancy will be insufficient. More preferably, it is 11 parts by mass or more. If the amount of (B) a flame retardant having a benzene ring in its side chain exceeds 20 parts by mass, the flexibility of the resulting molded article will decrease. More preferably, it is 18 parts by mass or less, and even more preferably 16 parts by mass or less.

[0032] The antimony compound (C) used in the present invention can be made more flammable by being used in combination with a flame retardant (B) having a benzene ring in its side chain. Examples of antimony compounds (C) include antimony trioxide, antimony tetroxide, antimony pentoxide, antimony halides, and sodium antimonate, but antimony trioxide is preferred from the standpoint of availability. A preferred antimony trioxide is, for example, "Firecut" (registered trademark) AT-3 (product name) manufactured by Suzuhiro Chemical Co., Ltd.

[0033] The average particle size of the (C) antimony compound used in this invention is not particularly limited, but is preferably 1.0 to 2.0 μm, and more preferably 1.0 to 1.5 μm. When the particle size of the (C) antimony compound is within the above range, a high degree of flame retardancy can be obtained with a relatively small amount of additive.

[0034] The amount of (C) antimony compound in the flame-retardant thermoplastic resin composition of the present invention is 3 to 9 parts by mass per 100 parts by mass of the (A) polybutylene (terephthalate / dodecanediote) copolymer. If the amount of (C) antimony compound is less than 3 parts by mass, the flame retardant performance will be insufficient, making it difficult to use in applications where flame retardant performance is required. More preferably, it is 3 parts by mass or more, and even more preferably 5 parts by mass or more. If the amount of (C) antimony compound exceeds 9 parts by mass, it will be difficult to mix uniformly, the fluidity will decrease, and the flexibility of the resin composition will also decrease. More preferably, it is 7 parts by mass or less.

[0035] (B) To fully utilize the flame retardant properties of the flame retardant having a benzene ring in its side chain and (C) the antimony compound, it is most effective to blend (C) the antimony compound in a ratio of 1:3 to the halogen contained in the flame retardant having a benzene ring in its side chain.

[0036] In the present invention, it is preferable to further incorporate (D) dicyclopentadiene type epoxy resin as a hydrolysis inhibitor to impart resistance to moist heat.

[0037] The (D) dicyclopentadiene type epoxy resin used in the present invention is represented by the following general formula (1) and contains epoxy groups in its molecule.

[0038] [ka]

[0039] In the above general formula (1), n ​​represents the number of repeating units of the (D) dicyclopentadiene type epoxy resin. The number of repeating units n of the (D) dicyclopentadiene type epoxy resin used in the present invention is preferably in the range of 0 to 10. If the number of repeating units n is large, the reaction between the (D) dicyclopentadiene type epoxy resins proceeds easily, making it easier to form a crosslinked structure, which worsens the retention stability of the thermoplastic polyester resin composition. From the viewpoint of retention stability, the number of repeating units n of the dicyclopentadiene type epoxy resin is more preferably 0 to 4, and more preferably 1 to 3.

[0040] In the present invention, the (D) dicyclopentadiene-type epoxy resin is preferably blended in an amount of 0.3 parts by mass or more and 10.0 parts by mass or less per 100 parts by mass of the (A) thermoplastic polyester resin. If the amount is less than 0.3 parts by mass, the hydrolysis resistance will be insufficient. More preferably, it is 1.0 part by mass or more. If it exceeds 10.0 parts by mass, the viscosity will increase during melt retention. More preferably, it is 6.0 parts by mass or less, and even more preferably 3.0 parts by mass or less.

[0041] Commercially available dicyclopentadiene-type epoxy resins include "Epiclon" (trademark registered), HP-7200H (manufactured by DIC Corporation), and XD-1000 (manufactured by Nippon Kayaku Co., Ltd.).

[0042] The thermoplastic resin composition of the present invention preferably has a flexural modulus of less than 1.00 GPa, measured in accordance with ISO 178 as an indicator of flexibility, and a tensile strain of 100% or more, measured in accordance with ISO 527. If the flexural modulus is 1.00 GPa or more, the resin tends to be less flexible. On the other hand, if the tensile strain is less than 100%, the resin becomes brittle, making it difficult to bend extruded products. If the flexural modulus is less than 1.00 GPa, the resin has good flexibility and excellent extruderability. On the other hand, if the tensile strain is 100% or more, the resin becomes highly flexible, making it less prone to cracking and wrinkling when extruded products are bent.

[0043] Furthermore, the thermoplastic resin composition of the present invention preferably has a dielectric breakdown voltage of 50 to 100 kV in a 3 mm square plate, measured in accordance with IEC 60243-1, as an indicator of dielectric breakdown characteristics. If the dielectric breakdown characteristic is 50 kV or higher, the molded product can withstand high voltages.

[0044] Furthermore, the thermoplastic resin composition of the present invention preferably has a melt mass flow rate (MFR value) of 10.0 g / 10 min or less at a measured temperature of 250°C and a load of 1000 g, in accordance with ISO 1133 as an indicator of extrusion moldability, and more preferably 6.0 g / 10 min or less. An MFR value of 10.0 g / 10 min or less suppresses drawdown during extrusion molding, improving extrusion moldability.

[0045] To achieve the aforementioned flexibility, dielectric breakdown properties, and extrudeability, the resin composition must consist of (A) 100 parts by mass of polybutylene (terephthalate / dodecanediote) copolymer, (B) 10 to 20 parts by mass of polypentabromobenzyl acrylate, (C) 3 to 9 parts by mass of antimony compound, and optionally (D) 0.3 to 10.0 parts by mass of dicyclopentadiene type epoxy resin. Preferably, the dodecanedionic acid component content in the total dicarboxylic acid components of the (A) polybutylene (terephthalate / dodecanediote) copolymer is 10 to 20 mol%. The thermoplastic resin composition of the present invention may contain conventional additives such as lubricants and colorants other than (A) polybutylene (terephthalate / dodecanediote) copolymer, (B) polypentabromobenzyl acrylate, (C) antimony compound, and (D) dicyclopentadiene type epoxy resin, as long as they do not impair the effects of the present invention. You may combine two or more of these ingredients.

[0046] In the present invention, the release properties during molding can be further improved by adding one or more lubricants. Examples of such lubricants include, but are not limited to, metal soaps such as calcium stearate and barium stearate, fatty acid esters, salts of fatty acid esters (including those in which only a portion is a salt), fatty acid amides such as ethylenebisstearoamide, fatty acid amides consisting of a polycondensate of ethylenediamine, stearic acid, and sebacic acid or a polycondensate of phenylenediamine, stearic acid, and sebacic acid, polyalkylene waxes, acid anhydride-modified polyalkylene waxes, and mixtures of the above lubricants with fluorine-based resins or fluorine-based compounds. When a lubricant is added, the amount is preferably 0.01 to 5 parts by mass, more preferably 0.02 to 4 parts by mass, and more preferably 0.03 to 3 parts by mass, per 100 parts by mass of (A) polybutylene (terephthalate / dodecanediate) copolymer.

[0047] In the present invention, the resin can be colored to various colors by further blending carbon black, titanium dioxide, and one or more pigments or dyes of various colors, thereby improving weather resistance (light resistance) and conductivity. The amount of pigment or dye blended is preferably 0.01 to 5 parts by mass, more preferably 0.02 to 4 parts by mass, and more preferably 0.03 to 3 parts by mass, per 100 parts by mass of (A) polybutylene (terephthalate / dodecanedioate) copolymer.

[0048] Furthermore, while not limited to the above, examples of carbon black include channel black, furnace black, acetylene black, anthracene black, oil soot, pine soot, and graphite, with an average particle size of 500 nm or less and a dibutyl phthalate oil absorption capacity of 50-400 cm³. 3 Carbon black is preferably used in 100g portions, and may be treated with aluminum oxide, silicon oxide, zinc oxide, zirconium oxide, polyol, silane coupling agent, etc.

[0049] Furthermore, as the titanium dioxide mentioned above, titanium dioxide having a crystalline form such as rutile or anatase and with an average particle size of 5 μm or less is preferably used, and may be treated with aluminum oxide, silicon oxide, zinc oxide, zirconium oxide, polyol, silane coupling agent, etc. as a treatment agent. In addition, the carbon black, titanium dioxide, and various colored pigments and dyes mentioned above may be used as a mixed material by melt-blending or simply blending with various thermoplastic resins in order to improve dispersibility with the thermoplastic resin composition of the present invention and to improve handling during manufacturing. In particular, as the thermoplastic resin, (A) polybutylene (terephthalate / dodecanediote) copolymer or polybutylene terephthalate resin is preferably used.

[0050] Next, a method for producing the thermoplastic resin composition of the present invention will be described.

[0051] The thermoplastic resin composition of the present invention is produced by commonly known methods. For example, the thermoplastic polyester resin composition of the present invention is prepared by pre-mixing (A) polybutylene (terephthalate / dodecanediate) copolymer, (B) polypentabromobenzyl acrylate, and (C) antimony compound, and optionally (D) dicyclopentadiene type epoxy resin, lubricants and other necessary additives, as well as colorants such as pigments and dyes, or by supplying them to an extruder or the like and thoroughly melt-kneading them, either pre-mixing or without pre-mixing.

[0052] As an example of the above pre-mixing, dry blending alone is possible, but mixing can also be done using mechanical mixing equipment such as tumblers, ribbon mixers, and Henschel mixers. In the case of liquid additives, methods such as installing a liquid addition nozzle between the loading and vent sections of a multi-screw extruder, such as a twin-screw extruder, and adding the liquid using a plunger pump, or supplying it from the loading section using a metering pump, may also be used.

[0053] Furthermore, when manufacturing the thermoplastic resin composition of the present invention, although not limited to these, a single-screw extruder, twin-screw extruder, tri-screw extruder, conical extruder, and kneader-type kneader equipped with a "Unimelt" or "Dalmege" type screw can be used, but is not limited to these.

[0054] The thermoplastic resin composition thus obtained possesses material properties suitable for extrusion molding, and the molded article of the present invention can be obtained by extrusion molding using commonly known methods. When performing extrusion molding, it is possible to mold under conditions that are almost the same as those used when extruding the base polymer matrix. Specifically, if a crystalline thermoplastic resin is used as the matrix resin, it is preferable to mold at a temperature 20°C to 50°C higher than the melting point, and if an amorphous thermoplastic resin is used as the matrix, it is preferable to mold at a temperature 100°C to 150°C higher than the glass transition temperature.

[0055] The thermoplastic resin composition of the present invention is excellent in flexibility, dielectric breakdown properties, and extrusion moldability, and can be used in a variety of applications such as automotive parts, electrical and electronic components, building materials, various containers, daily necessities, household goods, and hygiene products. It is particularly useful for molded products used as components that require high flexibility and dielectric breakdown properties. Furthermore, the resulting product (component) exhibits excellent adhesion between the inserted electronic component and the resin, making delamination between the resin and the electronic component unlikely. Therefore, even when used for a long period of time in harsh environments, delamination between the resin and the electronic component does not occur, and cracks or breaks are unlikely to occur in the resin portion. [Examples]

[0056] Next, the present invention will be described in more detail using examples. The abbreviations and contents of the raw materials used in the examples and comparative examples are shown below.

[0057] (A) Polybutylene (terephthalate / dodecadioate) copolymer, measured in accordance with ISO 1133 at a temperature of 250°C and a load of 1000g, having a melt mass flow rate of 3.0 g / 10 min or less. (A-1) Polybutylene (terephthalate / dodecadioate) copolymer (dodecandionic acid content 13 mol%): 106.2 parts by mass of terephthalic acid, 22.0 parts by mass of dodecandionic acid, 84.1 parts by mass of 1,4-butanediol, and 0.08 parts by mass of tetrabutyl titanate and 0.07 parts by mass of monobutyltin oxide as catalysts were charged into a reaction vessel equipped with a rectification column and a stirrer, and the temperature was raised from 150°C to 235°C over 4 hours under atmospheric pressure to carry out the esterification reaction. The resulting water and tetrahydrofuran were removed by distillation through the rectification column to obtain a tetrahydrofuran-containing product. Next, 0.03 parts by mass of phosphoric acid as a color inhibitor and 0.08 parts by mass of tetrabutyl titanate as a polycondensation catalyst were added to the esterification reaction product. The mixture was then transferred to a polycondensation reaction vessel, where the pressure was gradually reduced from atmospheric pressure to 67 Pa over 50 minutes, while simultaneously raising the temperature to 245°C. The polycondensation reaction was carried out for 2 hours and 50 minutes, and the relative viscosity at 25°C, measured with a 0.5% by mass orthochlorophenol solution, was 1.48, yielding a polybutylene (terephthalate / dodecadioate) copolymer. The obtained copolymer was placed in a vacuum dryer and solid-phase polymerization was carried out for a certain period of time under conditions of a vacuum of 760 mmHg and 180°C. When the obtained copolymer was measured with a 0.5% by mass orthochlorophenol solution, the relative viscosity at 25°C was 2.01. The MFR value at a temperature of 250°C and a load of 1000 g was 1.6 g / 10 min.

[0058] (A') A resin other than polybutylene (terephthalate / dodecadioate) copolymer, in accordance with ISO 1133, with a melt mass flow rate of 3.0 g / 10 min or less, measured at a temperature of 250°C and a load of 1000 g. (A'-1) Polybutylene (terephthalate / dodecadioate) copolymer (13 mol% dodecandionic acid copolymer PBT resin): Esterification and polycondensation reactions were carried out in the same manner as in (A-1), but solid-phase polymerization was not performed. The obtained polybutylene (terephthalate / dodecadioate) copolymer was measured in a 0.5 mass% orthochlorophenol solution, and the relative viscosity at 25°C was 1.48. In accordance with ISO 1133, the MFR value at a temperature of 250°C and a load of 1000 g was 37.0 g / 10 min. (A'-2) Polybutylene terephthalate resin: A PBT resin was used in which the relative viscosity at 25°C measured with a 0.5% by mass orthochlorophenol solution was 1.70, and the MFR value at 250°C and a load of 1000g was 4.0g / 10min in accordance with ISO 1133. (A'-3) Polybutylene terephthalate resin: A PBT resin was used in which the relative viscosity at 25°C measured with a 0.5% by mass orthochlorophenol solution was 1.57, and the MFR value at 250°C and a load of 1000g was 9.0g / 10min in accordance with ISO1133. (B) Flame retardants having a benzene ring in the side chain (B-1) Polypentabromobenzyl acrylate: FR-1025 (product name) manufactured by ICL JAPAN Co., Ltd., Mw: 31,000 (B') Flame retardants that do not have a benzene ring in the side chain (B'-1) Brominated polycarbonate: Tetrabromobisphenol-A-carbonate oligomer, manufactured by Teijin Limited, “Fireguard” (registered trademark) FG-8500 (product name) (B'-2) Brominated epoxy: Brominated epoxy resin with tribromophenol end caps, manufactured by ICL JAPAN Co., Ltd., product name F-3060. (C) Antimony compound (C-1) Antimony trioxide: "Firecut" (registered trademark) AT-3CN (product name), manufactured by Suzuhiro Chemical Co., Ltd. (D) Dicyclopentadiene type epoxy resin (D-1) Dicyclopentadiene type epoxy resin represented by general formula (1) with an epoxy equivalent weight of 290 g / eq (manufactured by DIC Corporation, “Epiclon” (registered trademark) HP-7200H (product name)) (E) Other resins (E-1) Olefin-based elastomer: Ethylene / vinyl acetate / methyl acrylate glycidyl methacrylate copolymer, manufactured by Sumitomo Chemical Co., Ltd. “BONDFAST” (registered trademark) ETX-6 (product name) (E-2) Olefin-based elastomer: Ethylene-α-olefin copolymer, manufactured by Mitsui Chemicals, Inc. "Toughmar" (registered trademark) A-4085S (product name) In the examples and comparative examples, their characteristics were evaluated by the measurement methods described below.

[0059] (1) Meltmass flow rate (MFR) The (A) polybutylene (terephthalate / dodecadioate) copolymer used in each example and comparative example, and the thermoplastic resin composition pellets obtained in each example and comparative example, were dried in a hot air dryer at 130°C for 3 hours or more. Then, in accordance with ISO 1133, an MFR measuring instrument was used to melt the thermoplastic resin and thermoplastic resin composition in a heated cylinder at 250°C. A load of 1000g was applied, and the mass of resin flowing out of the orifice (2.095Φ) within a certain time was measured, and the melt mass flow rate (MFR value) was calculated.

[0060] (2) Tensile strength and tensile strain After drying the thermoplastic resin composition pellets obtained in each example and comparative example in a hot air dryer at 130°C for more than 3 hours, multi-purpose test specimens of type A (total length 150 mm, test section width 10 mm, thickness 4 mm) as specified in ISO 3167 were prepared using a Sumitomo Heavy Industries injection molding machine "SE75DU" under conditions of cylinder temperature 240-270°C and mold temperature 80°C. Tensile strength and tensile strain were measured using five of each obtained test specimen in accordance with ISO 527-1,2. A tensile strain of 100% or more was judged to indicate good durability during bending.

[0061] (3) Flexural modulus After drying the thermoplastic resin composition pellets obtained in each example and comparative example in a hot air dryer at 130°C for at least 3 hours, multi-purpose test specimens of type A (total length 150 mm, test section width 10 mm, thickness 4 mm) as specified in ISO 3167 were prepared using a Sumitomo Heavy Industries injection molding machine "SE75DU" under conditions of cylinder temperature 240-270°C and mold temperature 80°C. The flexural modulus of elasticity was measured using five of each obtained test specimen in accordance with ISO 178. A flexural modulus of less than 1.00 GPa was considered to indicate good flexibility for the resin composition used to coat the busbars.

[0062] (4) Charpy impact strength After drying the thermoplastic resin composition pellets obtained in each example and comparative example in a hot air dryer at 130°C for more than 3 hours, multi-purpose test specimens of type A (total length 150 mm, test section width 10 mm, thickness 4 mm) as specified in ISO 3167 were prepared using a Sumitomo Heavy Industries injection molding machine "SE75DU" under conditions of cylinder temperature 240-270°C and mold temperature 80°C. For each of the 10 obtained test specimens, notches were made in strip test specimens (80 mm × 10 mm × 4 mm) cut from the parallel section, leaving 8 mm remaining, and the Charpy impact strength was measured in accordance with ISO 179. The Charpy impact strength was 5.0 kJ / m 2 The above criteria were considered satisfactory.

[0063] (5) Temperature of deflection under load After drying the thermoplastic resin composition pellets obtained in each example and comparative example in a hot air dryer at 130°C for at least 3 hours, test specimens (total length 80 mm, test section width 10 mm, thickness 4 mm) as specified in ISO 316 were prepared using a Sumitomo Heavy Industries injection molding machine "SE75DU" under conditions of cylinder temperature 240-270°C and mold temperature 80°C. The load deflection temperature was measured using five of each obtained test specimen in accordance with ISO 75. A load deflection temperature of 60°C or higher was considered good.

[0064] (6) Dielectric breakdown voltage After drying the thermoplastic resin composition pellets obtained in each example and comparative example in a hot air dryer at 130°C for more than 3 hours, small square plates (80 mm long, 80 mm wide, 3 mm thick) were fabricated using a Sumitomo Heavy Industries injection molding machine "SE50DU" under conditions of cylinder temperature 240-270°C and mold temperature 80°C. The dielectric breakdown voltage was measured using 5 test pieces of each obtained material in accordance with IEC60243-1. A dielectric breakdown voltage of 50 kV / mm or higher was considered to indicate good electrical resistance for high-voltage industrial resin compositions.

[0065] (7) Flammability After drying the thermoplastic resin compositions obtained in each example and comparative example in a hot air dryer at 130°C for at least 3 hours, rod-shaped test specimens (125 mm × 13 mm × 0.8 mm thickness) were prepared using a film gate with a Sumitomo Heavy Industries injection molding machine "SE75DU". The injection conditions were a cylinder temperature of 240-270°C and a mold temperature of 80°C. The obtained test specimens were left for 48 hours in a 23°C, 50% RH environment, and then the vertical flammability was measured in accordance with UL-94. Ten test specimens were tested, and the results were determined as V-0, V-1, V-2, and V-out according to UL-94. A V-0 result indicated good flame retardancy for an industrial resin composition for high voltage applications.

[0066] (8) Melting point The thermoplastic resin composition pellets obtained in each example and comparative example were measured using a differential scanning calorimeter (Diamond DSC, PerkinElmer) under a nitrogen atmosphere, with the melting point defined as the peak of endothermic heat due to crystal melting that appeared when the temperature was increased from 40°C to 300°C at a rate of 20°C / min.

[0067] [Examples 1-4] and [Comparative Examples 1-6] According to the formulation shown in Table 1, (A) polybutylene (terephthalate / dodecadioate) copolymer, (B) flame retardant having a benzene ring in the side chain, (C) antimony compound, and (D) dicyclopentadiene type epoxy resin were supplied from the loading section of a twin-screw extruder (Toshiba Machine TEM37) with a screw diameter of 37 mmφ set to a cylinder temperature of 260°C, and melt-mixed. After cooling the strands extruded from the die in a cooling bath, they were pelletized with a strand cutter to obtain a thermoplastic resin composition. The results of evaluating the obtained flame-retardant thermoplastic resin composition using the above method are shown in Table 1.

[0068] The resulting thermoplastic resin compositions all yielded molded articles with excellent flexibility, flame retardancy, and dielectric breakdown properties.

[0069] Comparing Examples 1-3 with Comparative Examples 1-3, when brominated polycarbonate with benzene rings in the main chain was used instead of (B) the flame retardant with benzene rings in the side chain, the flexural modulus increased, the flexibility required for bending decreased, and the dielectric breakdown characteristics also decreased because it was easier to form electrical pathways. Furthermore, when brominated polycarbonate was used, the flammability decreased unless the amount added was increased compared to (B) the flame retardant with benzene rings in the side chain.

[0070] Comparing Examples 1-3 with Comparative Example 4, when using (A'-1) polybutylene (terephthalate / dodecadioate) copolymer with an MFR value of 3.0 g / 10 min or higher, the MFR value of the thermoplastic resin composition after compounding becomes 10.0 g / 10 min or higher, resulting in poor extrusion moldability.

[0071] Comparing Examples 1-3 with Comparative Example 5, when an elastomer is added to (A'-2) polybutylene terephthalate resin with an MFR value of 3.0 g / 10 min or higher, and the MFR value of the thermoplastic resin composition after compounding is reduced to 10.0 g / 10 min or lower, the tensile strain decreases, the flexural modulus increases, flexibility decreases, and flammability also decreases.

[0072] Comparing Examples 1-3 with Comparative Example 6, when an elastomer is added to (A'-2) polybutylene terephthalate resin and the MFR value of the thermoplastic resin composition after compounding is reduced to 10.0 g / 10 min or less, the tensile strain decreases, the flexural modulus increases, flexibility decreases, and flammability also decreases.

[0073] [Table 1]

Claims

1. A thermoplastic resin composition comprising (A) 100 parts by mass of a polybutylene (terephthalate / dodecadioate) copolymer having a melt mass flow rate of 3.0 g / 10 min or less, measured at a temperature of 250°C and a load of 1000 g in accordance with ISO 1133, (B) 10 to 20 parts by mass of a flame retardant having a benzene ring in its side chain, and (C) 3 to 9 parts by mass of an antimony compound.

2. Furthermore, the thermoplastic resin composition according to claim 1, comprising (A) 100 parts by mass of a polybutylene (terephthalate / dodecadioate) copolymer having a melt mass flow rate of 3.0 g / 10 min or less, measured in accordance with ISO 1133 at a temperature of 250°C and a load of 1000 g, and (D) 0.3 to 10.0 parts by mass of a dicyclopentadiene type epoxy resin.

3. The thermoplastic resin composition according to claim 1 or 2, wherein the flexural modulus measured in accordance with ISO 178 is less than 1.00 GPa, and the tensile strain measured in accordance with ISO 527 is 100% or more.

4. The thermoplastic resin composition according to claim 1 or 2, wherein the dielectric breakdown voltage IEC60243-1 measured on a 3 mm square plate is 50 kV or more.

5. The thermoplastic resin composition according to claim 1 or 2, wherein the melt mass flow rate value measured at a temperature of 250°C and a load of 1000g in accordance with ISO 1133 is 10.0 g / 10 min or less.

6. A molded article comprising the flame-retardant thermoplastic resin composition according to claim 1 or 2.

7. An extruded article obtained by extruding the flame-retardant thermoplastic resin composition according to claim 1 or 2.

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