Polyester resin expanded beads, molded article, and method for producing polyester resin expanded beads

Abstract

An object of the present invention is to provide polyester resin expanded beads having excellent flame retardancy, a molded article, and a method for producing polyester resin expanded beads.SOLUTION: Polyester-based resin expanded particles comprising a flame-retardant resin composition having a thermoplastic resin and a phosphorus-based flame retardant, wherein the flame-retardant resin composition contains a polyester-based resin, a polyimide-based resin, and a polyphenylene ether-based resin, a content of the polyimide-based resin is 10% by mass or more and 30% by mass or less, a content of the polyphenylene ether-based resin is 3% by mass or more and 15% by mass or less, and a content of the phosphorus-based flame retardant is 3% by mass or more and 10% by mass or less.SELECTED DRAWING: Figure 1A

Description

[Technical Field]

[0001] The present invention relates to expanded polyester resin beads, a molded article, and a method for producing expanded polyester resin beads. [Background technology]

[0002] A molded article (expanded thermoplastic resin bead molded article) obtained by filling a mold with expanded beads containing a thermoplastic resin (expanded thermoplastic resin beads) and heating them to thermally fuse a plurality of expanded beads together is also called a bead expanded molded article, etc. It is lightweight and has excellent heat insulation, shock absorption, and mechanical strength. For this reason, the application of expanded thermoplastic resin bead molded articles (sometimes simply referred to as "expanded bead molded articles" or "molded articles") to automobiles, aircraft, railway vehicles, etc. is being considered.

[0003] Among thermoplastic resins, polyester resins such as polyethylene terephthalate (PET) can be used to produce foamed bead moldings with excellent rigidity and heat resistance, and research into foamed bead moldings using polyester resins is currently underway.

[0004] One method for producing an expanded bead molding is in-mold foam molding. The in-mold foam molding will now be described. Expanded thermoplastic resin beads (sometimes simply referred to as "expanded beads") are filled into the cavity of a mold. The expanded beads in the cavity are heated with a heating medium such as hot water or steam to expand and become secondary expanded beads, and the expansion pressure of the expanded beads causes the secondary expanded beads to thermally fuse together and integrate, thereby obtaining an expanded bead molding of the desired shape.

[0005] Incidentally, flame retardancy is required for molded articles of expanded beads containing polyester resin (expanded polyester resin beads). For example, Patent Document 1 describes an invention of expanded polyester resin beads that are imparted with flame retardancy by adjusting the contents of polyester resin, polyimide resin, and phosphorus-based flame retardant contained in the expanded polyester resin beads to specific ranges. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] International Publication No. 2023 / 238958 Summary of the Invention [Problem to be solved by the invention]

[0007] However, sufficient flame retardancy is not obtained even with the invention described in Patent Document 1. In other words, further investigation is required to obtain expanded polyester resin beads with better flame retardancy.

[0008] Therefore, an object of the present invention is to provide expanded polyester resin beads, molded articles, and a method for producing expanded polyester resin beads, which are excellent in flame retardancy. [Means for solving the problem]

[0009] The expanded polyester resin particles according to the present invention are A polyester-based resin foam particle composed of a flame-retardant resin composition containing a thermoplastic resin and a phosphorus-based flame retardant, The flame-retardant resin composition contains a polyester-based resin, a polyimide-based resin, and a polyphenylene ether-based resin, The content of the polyimide resin is 10% by mass or more and 30% by mass or less, The content of the polyphenylene ether resin is 3% by mass or more and 15% by mass or less, The content of the phosphorus-based flame retardant is 3% by mass or more and 10% by mass or less.

[0010] The molded body according to the present invention is A molded article comprising a plurality of expanded particles containing a thermoplastic resin, the expanded particles being heat-fused to one another, The expanded beads are the polyester resin expanded beads.

[0011] The method for producing expanded polyester resin beads according to the present invention comprises the steps of: melt-kneading a polyester resin, a polyimide resin, a polyphenylene ether resin, a phosphorus-based flame retardant, and a foaming agent; and foaming and granulating the melt-kneaded product obtained by the melt-kneading, The content of the polyimide resin is 10% by mass or more and 30% by mass or less, The content of the polyphenylene ether resin is 3% by mass or more and 15% by mass or less, Expanded polyester resin particles containing the phosphorus-based flame retardant in an amount of 3% by mass or more and 10% by mass or less are produced. [Effects of the Invention]

[0012] According to the present invention, expanded polyester resin beads and molded articles having excellent flame retardancy, and a method for producing expanded polyester resin beads are provided. [Brief explanation of the drawings]

[0013] [Figure 1A] Enlarged cross-sectional view of the molded body of Example 1 obtained by TEM observation [Figure 1B] Enlarged cross-sectional view of the molded body of Example 1 obtained by TEM observation [Figure 1C] Enlarged cross-sectional view of the molded body of Example 1 obtained by TEM observation [Figure 1D] Enlarged cross-sectional view of the molded body of Example 1 obtained by TEM observation [Figure 1E] Enlarged cross-sectional view of the molded body of Example 1 obtained by TEM observation [Figure 1F] Enlarged cross-sectional view of the molded body of Example 1 obtained by TEM observation [Figure 2A] Enlarged cross-sectional view of the molded body of Comparative Example 1 obtained by TEM observation [Figure 2B] Enlarged cross-sectional view of the molded body of Comparative Example 1 obtained by TEM observation [Figure 2C] Enlarged cross-sectional view of the molded body of Comparative Example 1 obtained by TEM observation [Figure 2D] Enlarged cross-sectional view of the molded body of Comparative Example 1 obtained by TEM observation [Figure 2E] Enlarged cross-sectional view of the molded body of Comparative Example 1 obtained by TEM observation [Figure 2F] Enlarged cross-sectional view of the molded body of Comparative Example 1 obtained by TEM observation DETAILED DESCRIPTION OF THE INVENTION

[0014] An embodiment of the present invention will be described below.

[0015] [Polyester resin foam particles] The expanded polyester resin beads according to this embodiment (hereinafter sometimes simply referred to as "expanded beads") are composed of a flame-retardant resin composition containing a thermoplastic resin and a phosphorus-based flame retardant. In one embodiment, the expanded beads are particulate foams. The expanded beads are used as a raw material for molded articles formed by so-called in-mold foam molding.

[0016] The flame-retardant resin composition constituting the polyester-based resin foam particles according to this embodiment contains a polyester-based resin, a polyimide-based resin, and a polyphenylene ether-based resin, which will be hereinafter referred to as polyester-based resin (A), polyimide-based resin (B), and polyphenylene ether-based resin (C).

[0017] The expanded polyester resin particles according to this embodiment may have a matrix-domain structure comprising a matrix phase containing the polyester resin (A) and a domain phase containing the polyphenylene ether resin (C).

[0018] The polyimide resin (B) has a high affinity with the polyester resin (A) and is uniformly dispersed in the polyester resin (A). When it is used alone, it diffuses into the polyester resin at the molecular level or, if it aggregates, only forms fine domains. On the other hand, the polyphenylene ether resin (C) has a low affinity with the polyester resin (A). It does not disperse uniformly in the polyester resin (A), forming a domain phase as relatively large particles. The polyphenylene ether resin (C) forms a domain phase, which allows the melt viscosity of the entire thermoplastic resin to be maintained relatively high. These domains function to prevent the flame-retardant resin composition from becoming highly fluid at temperatures above the melting point of the polyester resin (A). The high melt viscosity of the entire thermoplastic resin prevents flame dripping even when the polyester resin expands. This allows the polyester resin expand to exhibit even better flame retardancy.

[0019] Generally, when a resin product ignites, the resin composition constituting the resin product is heated by the flame to above its thermal decomposition temperature, converting it into flammable gas. The generation of this flammable gas can further contribute to the continued combustion of the resin product. In contrast, phosphorus-based flame retardants effectively suppress flames by forming a charred layer, known as char, during the thermal decomposition of the resin composition. This charred layer acts as both an insulating layer between the unburned resin product and the flame and a gas barrier layer, thereby providing a flame-extinguishing effect. However, resin compositions with low melting points and low melt viscosities melt and flow off during combustion before the char reaches a certain thickness, making it difficult to fully exert their flame-extinguishing effect and suppress flame dripping. Expanded polyester resin particles contain a domain phase containing a resin with a high softening point, such as polyphenylene ether resin (C), which increases the melt viscosity of the entire thermoplastic resin, thereby providing even better flame retardancy.

[0020] The occurrence of microphase separation including a matrix phase and a domain phase in the expanded polyester resin beads can be confirmed by staining a thin specimen cut from the expanded polyester resin beads and observing it with a transmission electron microscope (TEM).

[0021] Observation of the expanded polyester resin beads and their molded articles using a transmission electron microscope (TEM) can be carried out under the following measurement conditions. A section is cut from near the center of a single foam bead. The section is embedded in epoxy resin. The epoxy resin is cured at 60°C for 24 hours to produce a hardened body. The hardened body is sliced ​​using a Leica EM UC7 ultramicrotome manufactured by Leica Microsystems, to prepare ultrathin sections (70 nm thick). The ultrathin sections are then stained using ruthenium tetroxide as a staining agent. The ultrathin sections are photographed using a Hitachi High-Technologies Corporation HT7800 transmission electron microscope and a Hitachi High-Technologies Corporation RC16M camera.

[0022] (Polyester resin (A)) Examples of the polyester resin (A) include polyethylene terephthalate resin (PET), polybutylene terephthalate resin (PBT), polyethylene naphthalate resin (PEN), polyethylene furanoate resin (PEF), polybutylene naphthalate resin (PBN), polytrimethylene terephthalate resin (PTT), a copolymer of terephthalic acid, ethylene glycol, and cyclohexanedimethanol, and mixtures thereof. The polyester resin (A) is preferably polyethylene terephthalate resin (PET). The polyethylene terephthalate resin (PET) may be an amorphous polyethylene terephthalate resin (A-PET) or a crystalline polyethylene terephthalate resin (C-PET), and is more preferably crystalline polyethylene terephthalate resin (C-PET). Crystalline polyethylene terephthalate resin (C-PET) can be confirmed to have crystallinity by observing an exothermic peak (e.g., a peak of 10 J / g or more) indicating crystallization at around 130°C during a second heating run (e.g., 10°C / min) after holding the resin above the melting peak temperature observed in differential scanning calorimetry (DSC) for a certain period of time (e.g., 5 minutes). The resin is then rapidly cooled (e.g., at a rate of -100°C / min or more). The resin exhibits crystallinity when heated (e.g., at a rate of 10°C / min) at a rate of 10°C / min. The polyester resin (A) may be a petrochemical-derived polyester resin, a plant-derived polyester resin such as bioPET, or a mixture thereof. Examples of plant-derived polyester resins include polyethylene terephthalate resin, plant-derived polyethylene furanoate resin, and plant-derived polytrimethylene terephthalate resin. The polyester resin (A) may also be made from recycled materials. These polyester resins (A) may be used alone or in combination.

[0023] The content of the polyester resin (A) in the expanded polyester resin particles is preferably 49 to 84% by mass.

[0024] (Polyimide resin (B)) The polyimide resin (B) is preferably a polymer containing a cyclic imide group as a repeating unit, more preferably a polymer having a melt-molded body. Examples of the polyimide resin (B) include polyetherimides described in U.S. Pat. No. 4,141,927, Japanese Patent No. 2,622,678, Japanese Patent No. 2,606,912, Japanese Patent No. 2,606,914, Japanese Patent No. 2,596,565, Japanese Patent No. 2,596,566, Japanese Patent No. 2,598,478, etc., and polyetherimides described in U.S. Pat. No. 2,598,536, Japanese Patent ... Examples of suitable polyimide resins include those described in Japanese Patent Publication No. 2599171, Japanese Patent Application Laid-Open No. 9-48852, Japanese Patent No. 2565556, Japanese Patent No. 2564636, Japanese Patent No. 2564637, Japanese Patent No. 2563548, Japanese Patent No. 2563547, Japanese Patent No. 2558341, Japanese Patent No. 2558339, and Japanese Patent No. 2834580. The main chain of the polyimide resin (B) may contain structural units other than cyclic imide, as long as the effects of the present invention are not impaired. Examples of structural units other than cyclic imide include aromatic, aliphatic, alicyclic, alicyclic ester units, and oxycarbonyl units. The polyimide resin (B) may also be made from recycled materials. The polyimide resin (B) may also be a plant-derived resin, such as biopolyimide. These polyimide resins (B) may be used alone or in combination of two or more.

[0025] The polyimide resin (B) is preferably a compound represented by the following formula (1): In formula (1), R is an aromatic group having 6 to 42 carbon atoms, and R' is at least one divalent organic group selected from the group consisting of divalent aromatic groups having 6 to 30 carbon atoms, aliphatic groups having 2 to 30 carbon atoms, and alicyclic groups having 4 to 30 carbon atoms, and p is a number representing a repeating unit.

[0026] [ka]

[0027] As the polyimide resin (B), a polyetherimide resin having a structural unit with an ether bond is preferred from the viewpoint of improving compatibility with the polyester resin (A).

[0028] The polyimide resin (B) can be prepared by a conventionally known production method. For example, the polyimide resin (B) can be obtained by dehydration condensation of either or both of a tetracarboxylic acid and its acid anhydride, which are raw materials from which R in formula (1) can be derived, with one or more compounds selected from the group consisting of aliphatic primary diamines and aromatic primary diamines, which are raw materials from which R' in formula (1) can be derived. Examples of production methods for the polyimide resin (B) include a method in which a raw material from which R can be derived and a raw material from which R' can be derived are reacted to produce a polyamic acid, which is obtained by thermal ring closure; a method in which the polyamic acid is chemically ring-closed using a chemical ring-closing agent such as pyridine or carbodiimide; and a method in which the tetracarboxylic anhydride and a diisocyanate from which R' can be derived are heated to decarboxylate and polymerize.

[0029] Examples of tetracarboxylic acids include pyromellitic acid, 1,2,3,4-benzenetetracarboxylic acid, 3,3',4,4'-biphenyltetracarboxylic acid, 2,2',3,3'-biphenyltetracarboxylic acid, 3,3',4,4'-benzophenonetetracarboxylic acid, 2,2',3,3'-benzophenonetetracarboxylic acid, bis(2,3-dicarboxyphenyl)methane, bis(3,4-dicarboxyphenyl)methane, 1,1'-bis(2,3-dicarboxyphenyl)ethane, and 2,2'-bis(3,4-dicarboxyphenyl)propane. Examples of suitable naphthalene tetracarboxylic acids include propane, 2,2'-bis(2,3-dicarboxyphenyl)propane, bis(3,4-dicarboxyphenyl)ether, bis(2,3-dicarboxyphenyl)ether, bis(3,4-dicarboxyphenyl)sulfone, bis(2,3-dicarboxyphenyl)sulfone, 2,3,6,7-naphthalenetetracarboxylic acid, 1,4,5,8-naphthalenetetracarboxylic acid, 1,2,5,6-naphthalenetetracarboxylic acid, 2,2'-bis[(2,3-dicarboxyphenoxy)phenyl]propane, and acid anhydrides thereof.

[0030] Examples of aromatic primary diamines include benzidine, diaminodiphenylmethane, diaminodiphenylethane, diaminodiphenylpropane, diaminodiphenylbutane, diaminodiphenyl ether, diaminodiphenyl sulfone, diaminodiphenylbenzophenone, o-phenylenediamine, m-phenylenediamine, p-phenylenediamine, tolylenediamine, and xylenediamine.

[0031] Examples of aliphatic primary diamines include ethylenediamine, 1,2-propanediamine, 1,3-propanediamine, 2,2-dimethyl-1,3-propanediamine, 1,6-hexamethylenediamine, 1,8-octamethylenediamine, 1,9-nonamethylenediamine, 1,10-decamethylenediamine, 1,11-undecamethylenediamine, 1,12-dodecamethylenediamine, 2,2,4-trimethylhexamethylenediamine, 2,4,4-trimethylhexamethylenediamine, 1,3-cyclohexanediamine, 1,4-cyclohexanediamine, 1,4-cyclohexanedimethylamine, 2-methyl-1,3-cyclohexanediamine, and isophoronediamine.

[0032] The expanded polyester resin particles according to this embodiment have a polyimide resin (B) content of 10% by mass or more and 30% by mass or less, preferably 15% by mass or more and 25% by mass or less, and more preferably 15% by mass or more and 23% by mass or less. When the polyimide resin (B) content is within the above range, the expanded polyester resin particles can exhibit excellent flame retardancy.

[0033] (Polyphenylene ether resin (C)) The polyphenylene ether resin (C) is preferably a compound represented by the following formula (2): 1 , R 2 , R 3 and R 4 are each independently hydrogen, halogen, an alkyl group, an alkoxy group, a phenyl group, etc., and n is an integer representing the degree of polymerization.

[0034] [ka]

[0035] The polyphenylene ether resin (C) is not particularly limited, but examples thereof include poly(2,6-dimethyl-1,4-phenylene) ether, poly(2,6-diethyl-1,4-phenylene) ether, poly(2-methyl-6-ethyl-1,4-phenylene) ether, poly(2-methyl-6-propyl-1,4-phenylene) ether, poly(2,6-dipropyl-1,4-phenylene) ether, poly(2-ethyl-6-propyl-1,4-phenylene) ether, poly(2,6-dibutyl-1,4-phenylene) ether, poly(2,6-dilauryl-1,4-phenylene) ether, and poly(2,6-diphenyl-1,4-diphenylene) ether. , poly(2,6-dimethoxy-1,4-phenylene) ether, poly(2,6-diethoxy-1,4-phenylene) ether, poly(2-methoxy-6-ethoxy-1,4-phenylene) ether, poly(2-ethyl-6-stearyloxy-1,4-phenylene) ether, poly(2,6-dichloro-1,4-phenylene) ether, poly(2-methyl-6-phenyl-1,4-phenylene) ether, poly(2,6-dibenzyl-1,4-phenylene) ether, poly(2-ethoxy-1,4-phenylene) ether, poly(2-chloro-1,4-phenylene) ether, poly(2,6-dibromo-1,4-phenylene) ether, etc. The polyphenylene ether resin (C) is preferably R 1 and R 2 is an alkyl group having 1 to 4 carbon atoms, and R 3 and R 4 is hydrogen or an alkyl group having 1 to 4 carbon atoms. These polyphenylene ether resins (C) may be used alone or in combination of two or more.

[0036] The melt mass flow rate (MFR) of the polyphenylene ether resin (C) is preferably 1 g / 10 min or more and 6 g / 10 min or less, more preferably 2 g / 10 min or more and 5 g / 10 min or less, and even more preferably 2 g / 10 min or more and 4 g / 10 min or less. When the melt viscosity of the polyphenylene ether resin (C) is within the above range, the expanded polyester resin particles can exhibit better flame retardancy.

[0037] The melt mass flow rate (MFR) of the polyphenylene ether resin (C) is measured under the following conditions using a "Melt Flow Index Tester (Automatic) 120-SAS" manufactured by Yasuda Seiki Seisakusho Co., Ltd., based on Method B b) of JIS K7210-1:1999 "Plastics - Determination of Melt Mass Flow Rate (MFR) and Melt Volume Flow Rate (MVR) of Thermoplastic Plastics - Part 1", which measures the time it takes for a piston to move a specified distance. Sample: 3g to 8g Preheat (1): 200 seconds Preheat (2): 30 seconds Test temperature: 300℃ Test load: 49.03N Piston travel distance (interval): 25mm The polyphenylene ether resin (C) is dried in a vacuum dryer at 90°C for 3 hours, and then the test is carried out three times using the above measurement method. The average of the obtained values ​​is used as the melt mass-flow rate (MFR) of the polyphenylene ether resin (C).

[0038] The mass average molecular weight of the polyphenylene ether resin (C) is preferably 50×10 3 Over 100 x 10 3 or less, more preferably 50×10 3 Over 90 x 10 3 or less, and more preferably 50×10 3 Over 80 x 10 3The expanded polyester resin particles can exhibit better flame retardancy when the mass average molecular weight of the polyphenylene ether resin (C) is within the above range.

[0039] The mass average molecular weight can be measured by the following method. Take 15 mg of sample, add 6 mL of chloroform, and shake gently by hand. Leave it for 6 ± 1.0 hours. After confirming that the sample is completely dissolved, filter it using a non-aqueous 0.45 μm chromatodisc manufactured by GL Sciences Inc. or a non-aqueous 0.45 μm syringe filter manufactured by Shimadzu GLC Corporation to obtain the measurement sample. Measure the measurement sample using a chromatograph under the following measurement conditions, and determine the mass average molecular weight of the sample from a previously prepared standard polystyrene calibration curve. [Measuring equipment] Measurement equipment: Tosoh Corporation's "HLC-8320GPC EcoSEC" gel permeation chromatograph (with built-in RI and UV detectors) [GPC measurement conditions] ·column <Sample side> Guard column: Tosoh Corporation TSK guard column HXL-H (6.0 mm x 4.0 cm) x 1 Measurement column: Tosoh Corporation TSKgel GMHXL (7.8 mm I.D. x 30 cm) x 2 in series <Reference side> Resistance tube (inner diameter 0.1 mm x 2 m) x 2 in series Column temperature: 40℃ Mobile phase: chloroform <Mobile phase flow rate> Sample pump: 1.0 mL / min Reference pump: 0.5 mL / min Detector: RI detector Injection volume: 50μL Measurement time: 25 minutes Sampling pitch: 500 ms

[0040] Standard polystyrene samples for calibration curves can be obtained from Showa Denko K.K. under the product names "STANDARD SM-105" and "STANDARD SH-75" and have mass average molecular weights of 5,620,000, 3,120,000, 1,250,000, 442,000, 151,000, 53,500, 17,000, 7,660, 2,900, and 1,320. Divide the above calibration curve standard polystyrene into groups A (5,620,000, 1,250,000, 151,000, 17,000, 2,900) and B (3,120,000, 442,000, 53,500, 7,660, 1,320). Weigh out groups A (2 mg, 3 mg, 4 mg, 4 mg, 4 mg) and dissolve them in 30 mL of chloroform. Weigh out groups B (3 mg, 4 mg, 4 mg, 4 mg, 4 mg) and dissolve them in 30 mL of chloroform. The standard polystyrene calibration curve is obtained by injecting 50 μL of each prepared solution A and B, and creating a calibration curve (cubic equation) from the retention times obtained after measurement. The mass average molecular weight is calculated using this calibration curve.

[0041] The expanded polyester resin particles according to this embodiment have a polyphenylene ether resin (C) content of 3% by mass to 15% by mass, preferably 3% by mass to 10% by mass, and more preferably 3% by mass to 7% by mass. When the expanded polyester resin particles have a polyphenylene ether resin (C) content within the above range, they can exhibit excellent flame retardancy.

[0042] (phosphorus-based flame retardant) Examples of phosphorus-based flame retardants include phosphate compounds, polyphosphate compounds, red phosphorus, organic phosphate ester compounds, phosphazene compounds, phosphonic acid compounds, phosphinic acid compounds, phosphine oxide compounds, phosphorane compounds, and phosphoramide compounds. Examples of phosphate compounds include melamine phosphate, guanidine phosphate, ammonium phosphate, ammonium amide phosphate, and carbamate phosphate. Examples of polyphosphate compounds include melamine polyphosphate, guanidine polyphosphate, ammonium polyphosphate, ammonium amide phosphate, and carbamate polyphosphate. The above-mentioned phosphorus-based flame retardants may be used alone or in combination of two or more. These phosphorus-based flame retardants may be used in combination with flame retardants other than phosphorus-based flame retardants, such as halogen-based flame retardants, nitrogen-based flame retardants, silicon-based flame retardants, and inorganic flame retardants, as long as the effects of the present invention are not impaired.

[0043] The content of the phosphorus-based flame retardant in the expanded polyester resin particles is 3% by mass or more and 10% by mass or less, and preferably 4% by mass or more and 8% by mass or less. When the content of the phosphorus-based flame retardant in the expanded polyester resin particles is within the above range, the expanded polyester resin particles can exhibit excellent flame retardancy.

[0044] (Other resins) The expanded polyester resin particles are substantially free of thermosetting resin. "Substantially free" means that the expanded polyester resin particles contain no thermosetting resin or contain only a small amount of thermosetting resin that does not affect the quality of the expanded polyester resin particles. The content of the thermosetting resin in the expanded polyester resin particles is preferably 5.0% by mass or less, more preferably 2.0% by mass or less, even more preferably 1.0% by mass or less, and particularly preferably 0% by mass.

[0045] The flame-retardant resin composition constituting the expanded polyester resin particles may contain a thermoplastic resin (other thermoplastic resin) other than the polyester resin (A), the polyimide resin (B), and the polyphenylene ether resin (C). Examples of the other thermoplastic resin include polyolefin resins such as polyethylene and polypropylene, polystyrene resins, polyamide resins, polycarbonate resins, polyarylate resins, polyphenylsulfone resins, polysulfone resins, and polyethersulfone resins.

[0046] The total content of the polyester-based resin (A), polyimide-based resin (B) and polyphenylene ether-based resin (C) relative to the total mass of the thermoplastic resin is preferably 90 mass% or more, more preferably 95 mass% or more, even more preferably 98 mass% or more, and particularly preferably 99 mass% or more.

[0047] (foaming agent) In the expanded polyester resin particles according to this embodiment, the thermoplastic resin may further contain a blowing agent. Known blowing agents can be used as the blowing agent. Blowing agents can be broadly divided into physical blowing agents and chemical blowing agents. Examples of physical blowing agents include hydrocarbons such as propane, normal butane, isobutane, normal pentane, isopentane, and hexane; ethers such as dimethyl ether; chlorofluorocarbons such as methyl chloride, 1,1,1,2-tetrafluoroethane, 1,1-difluoroethane, and monochlorodifluoromethane; carbon dioxide; and nitrogen. The blowing agent is preferably a hydrocarbon, dimethyl ether, carbon dioxide, or nitrogen, more preferably dimethyl ether, propane, normal butane, isobutane, carbon dioxide, or nitrogen, and even more preferably normal butane, isobutane, or carbon dioxide. These blowing agents may be used alone or in combination of two or more.

[0048] From the viewpoint of obtaining excellent processability through secondary or tertiary expansion, the foamed polyester resin beads according to this embodiment may contain a hydrocarbon as the foaming agent. At first glance, the foamed polyester resin beads may appear to be disadvantageous in terms of imparting excellent flame retardancy to molded articles due to the inclusion of hydrocarbons, which are flammable organic compounds with relatively low molecular weights. However, hydrocarbon foaming agents also have an excellent effect of plasticizing resins, which is advantageous in adhering the foamed polyester resin particles together in molded articles. This reduces the voids between particles in the molded article, and the hydrocarbon foaming agent may actually be advantageous in improving the flame retardancy of the molded article.

[0049] From the viewpoint of obtaining excellent flame retardancy, the foaming agent of the expanded polyester resin particles according to this embodiment may be carbon dioxide.

[0050] The content of the foaming agent is not particularly limited, but may be, for example, 0.2 parts by mass or more and 1.5 parts by mass or less per 100 parts by mass of the total of the thermoplastic resin and the phosphorus-based flame retardant.

[0051] The content of the blowing agent in the flame-retardant resin composition can be measured using GC-MS by the following method. 10 to 30 mg of sample is placed in a 20 mL vial and precisely weighed. The vial is sealed, placed in a gas chromatograph with an autosampler, and heated at 210°C for 20 minutes. The gas in the headspace of the heated vial is collected and quantitatively analyzed using the MHE (Multiple Headspace Extraction) method. The MHE method here is a quantitative determination method that utilizes the attenuation of peak area obtained by repeatedly releasing gas phase gas in gas-solid equilibrium. (GC measurement conditions) Measurement equipment: Perkin-Elmer "Clarus 680" gas chromatograph Column: Agilent Technologies "ZB-1" (1.0 μm x 0.25 mm φ x 60 m) Detector: FID (GC oven temperature rise conditions) Initial temperature: 50℃ (held for 6min) Heating rate: 40℃ / min (up to 250℃) Final temperature: 250℃ (held for 1.5min) Carrier gas: He Inlet temperature: 230℃ Detection temperature: 310℃ Range: 20 Vent gas: 30 mL / min (He) Additional gas: 5mL / min (He) Gas pressure: Initial pressure 18 Psi (10 min) Pressure increase rate: 0.5 Psi / min (up to 24 Psi) (HS measurement conditions) Measurement device: Perkin-Elmer "TurboMatrix HS40" headspace autosampler Heating temperature: 210°C, heating time: 20 min, pressurized gas pressure: 25 Psi, pressurized time: 1 min, needle temperature: 210°C, transfer line temperature: 210°C, sample introduction time: 0.08 min (Calculation conditions) Standard gas for calibration curve: Mixed gas manufactured by GL Sciences Inc. Mixed gas content: Isobutane approx. 1%, normal butane approx. 1%, balance nitrogen Calculation method: Calculate the amount of remaining gas in the sample using the MHE method. All results are converted to isobutane.

[0052] (Crosslinking agent) In the expanded polyester resin beads according to this embodiment, the flame-retardant resin composition may further contain a crosslinking agent. The expanded polyester resin beads according to this embodiment may be a crosslinked polyester resin in which at least a portion of the polyester resin is crosslinked with the crosslinking agent. By including a crosslinked polyester resin in the expanded polyester resin beads, the melt viscosity of the entire thermoplastic resin can be maintained relatively high. The high melt viscosity of the entire thermoplastic resin can prevent flame dripping even when the expanded polyester resin beads burn, thereby achieving even better flame retardancy.

[0053] Examples of the crosslinking agent include acid dianhydrides such as pyromellitic anhydride, polyfunctional epoxy compounds, oxazoline compounds, oxazine compounds, and cyclic carbodiimide compounds.

[0054] The content of the crosslinking agent in the expanded polyester resin particles is preferably 0.080% by mass or more and 0.80% by mass or less, more preferably 0.15% by mass or more and 0.50% by mass or less, even more preferably 0.20% by mass or more and 0.45% by mass or less, and particularly preferably 0.25% by mass or more and 0.40% by mass or less. When the content of the crosslinking agent in the expanded polyester resin particles is within the above range, the expanded polyester resin particles can exhibit even better flame retardancy.

[0055] (optional ingredient) In the expanded polyester resin particles according to this embodiment, the flame-retardant resin composition may contain other components (optional components) in addition to the thermoplastic resin, blowing agent, and crosslinking agent, such as a cell regulator, stabilizer, UV absorber, colorant, antioxidant, crystallization accelerator, lubricant, surfactant, shrinkage inhibitor, flame retardant, and deterioration inhibitor.

[0056] Examples of the cell control agent include a bubble nucleating agent, which serves as the starting point for bubble formation by the blowing agent in the melt-kneaded product when the flame-retardant resin composition is melt-kneaded to form expanded beads, or compound particles that generate gas upon thermal decomposition. Examples of the cell nucleating agent include those commonly used in extrusion foaming. Examples of the cell nucleating agent include particles of inorganic compounds such as talc, mica, silica, diatomaceous earth, aluminum oxide, titanium oxide, zinc oxide, magnesium oxide, magnesium hydroxide, aluminum hydroxide, calcium hydroxide, potassium carbonate, calcium carbonate, magnesium carbonate, potassium sulfate, barium sulfate, or glass beads, or particles of organic compounds such as polytetrafluoroethylene. The cell nucleating agent may be one of the compounds listed here, or a mixture of two or more. Examples of compound particles that generate gas upon thermal decomposition include azodicarbonamide, sodium bicarbonate, or a mixture of sodium bicarbonate and citric acid. The expanded polyester resin beads according to this embodiment preferably contain a bubble nucleating agent as the cell control agent.

[0057] These cell control agents increase the closed cell ratio of the expanded polyester resin beads, facilitating the formation of expanded polyester resin beads. The content of the cell control agent in the expanded polyester resin beads is, for example, 0.20% by mass or more and 5.0% by mass or less.

[0058] Examples of the stabilizer include calcium zinc-based heat stabilizers, tin-based heat stabilizers, lead-based heat stabilizers, etc. The content of the stabilizer in the expanded polyester resin particles is, for example, 1.0 mass % or less.

[0059] Examples of the ultraviolet absorber include cesium oxide-based ultraviolet absorbers, titanium oxide-based ultraviolet absorbers, etc. The content of the ultraviolet absorber in the expanded polyester resin particles is, for example, 1.0 mass % or less.

[0060] Examples of the antioxidant include cerium oxide, cerium oxide / zirconia solid solution, cerium hydroxide, carbon, carbon nanotubes, titanium oxide, and fullerene. The content of the antioxidant in the expanded polyester resin particles is, for example, 1.0 mass % or less.

[0061] Examples of colorants include titanium oxide, carbon black, titanium yellow, iron oxide, ultramarine, cobalt blue, calcined pigments, metallic pigments, mica, pearl pigments, zinc oxide, precipitated silica, and cadmium red. When the expanded polyester resin particles according to this embodiment are used in food containers, it is preferable to select from the above colorants those registered with the Hygienic Council of Japan. The content of the colorant in the expanded polyester resin particles is, for example, 2.0% by mass or less.

[0062] Examples of the crystallization accelerator include silicates, carbon, and metal oxides. Examples of silicates include talc, which is hydrous magnesium silicate. Examples of carbon include carbon black, carbon nanofibers, carbon nanotubes, carbon nanohorns, activated carbon, graphite, graphene, coke, mesoporous carbon, glassy carbon, hard carbon, and soft carbon. Examples of carbon black include furnace black, acetylene black, ketjen black, and thermal black. Examples of metal oxides include zinc oxide and titanium oxide. The content of the crystallization accelerator in the expanded polyester resin particles is, for example, 3.0% by mass or less.

[0063] The optional components may be used alone or in combination of two or more. The total amount of the optional components contained in the expanded polyester resin beads is preferably 0.10% by mass or more and 5.0% by mass or less, more preferably 0.50% by mass or more and 3.0% by mass or less, based on the expanded polyester resin beads.

[0064] The expanded polyester resin particles according to this embodiment have a bulk density of 0.08 g / cm 3More than 0.30g / cm 3 It may be the following:

[0065] The bulk density of the expanded polyester resin particles is measured in accordance with JIS K6911:1995 "General testing methods for thermosetting plastics." Measurement is performed using an apparent density measuring device in accordance with JIS K6911, and the bulk density of the expanded particles is calculated based on the following formula (s1). Bulk density of polyester resin foam particles (g / cm 3 ) = [mass of the measuring cylinder containing the polyester resin foam particles (g) - mass of the measuring cylinder (g)] / [capacity of the measuring cylinder (cm 3 )]···(s1)

[0066] The expanded polyester resin particles according to this embodiment may have an open cell ratio of 1% or more and 20% or less.

[0067] The open cell ratio of expanded polyester resin beads is measured by the following method. First, a sample cup for a volumetric air comparison hydrometer is prepared, and the total mass a (g) of the expanded polyester resin beads is measured, filling about 80% of the sample cup. Next, the total volume b (cm 3 ) is measured using a hydrometer at 1-1 / 2-1 atmospheres. For the measurement, a Tokyo Science "Volumetric Air Comparison Hydrometer Model 1000" is used. A wire mesh container is prepared, and the container is immersed in water, and the mass c (g) of the container is measured while it is immersed in water. All of the expanded polyester resin particles are placed in the container, and the container is immersed in water, and the combined mass d (g) of the container and the total amount of expanded polyester resin particles placed in the container while it is immersed in water is measured. The masses of the expanded polyester resin particles and the container are measured using an electronic balance HB3000 (minimum scale 0.01 g) manufactured by Yamato Seisei Co., Ltd. The apparent volume e (cm ) of the expanded polyester resin particles was calculated based on the following formula: 3) is calculated, and the apparent volume e and the total volume b (cm 3 ) and calculate the open cell ratio of the expanded polyester resin beads using the following formula (s2). 3 In addition, in this measurement, the expanded polyester resin particles are stored in advance in an environment of JIS K7100-1999 symbol 23 / 50, grade 2 for 16 hours, and then the measurement is carried out in the same environment. Open cell ratio (%) = 100 × (eb) / e (s2) (e=a+(cd))

[0068] The expanded polyester resin particles according to this embodiment are configured in the above manner, and thus have excellent flame retardancy.

[0069] [Molded body] The molded article according to this embodiment is composed of a plurality of expanded beads containing a thermoplastic resin, and the expanded beads are heat-fused to one another. The expanded beads are the polyester-based resin expanded beads described above. That is, the polyester-based resin expanded beads described above can be used as a material for molding to form a molded article.

[0070] The molded article according to this embodiment is obtained by expanding the polyester resin foam particles described above, so that the foam particles are thermally fused to one another. Applications of the molded article include components for transportation equipment such as automobiles, railroad vehicles, aircraft, and ships, cushioning materials and housings for electrical appliances, transport containers, packaging materials, structural members, and heat insulating materials. Examples of automobile components include battery cases, battery trays, components used near the engine, exterior materials, and heat insulating materials. Examples of railroad vehicle components include seat core materials, exterior materials, and heat insulating materials.

[0071] The molded body according to this embodiment has a density of 0.10 g / cm 3 More than 0.30g / cm 3 It may be less than 0.15 g / cm 3 More than 0.25g / cm 3or less, more preferably 0.15 g / cm 3 More than 0.24g / cm 3 The following is the result.

[0072] The density of the molded product is measured by the method described in JIS K7222:1999 "Foamed plastics and rubber - Measurement of apparent density". 3 The above compact is cut without changing the original cell structure of the material, and the mass is measured. The density is calculated using the following formula (s3). Density (g / cm 3 ) = mass of compact (g) / volume of compact (cm 3 )···(s3)

[0073] The molded article of this embodiment is configured in the above manner, and thus has excellent flame retardancy.

[0074] [Method of manufacturing expanded polyester resin beads] The method for producing expanded polyester resin particles according to this embodiment includes melt-kneading a polyester resin (A), a polyimide resin (B), a polyphenylene ether resin (C), a phosphorus-based flame retardant, and a blowing agent (kneading step), and expanding and granulating the molten mixture obtained by the melt-kneading step (expanding granulation step).

[0075] In the method for producing expanded polyester resin particles according to this embodiment, the content of the polyimide resin (B) is 10% by mass or more and 30% by mass or less, the content of the polyphenylene ether resin (C) is 3% by mass or more and 15% by mass or less, and the content of the phosphorus-based flame retardant is 3% by mass or more and 10% by mass or less. In the method for producing expanded polyester resin particles according to this embodiment, the polyester resin (A), polyimide resin (B), polyphenylene ether resin (C), phosphorus-based flame retardant, and blowing agent may be those described above.

[0076] The kneading step can be carried out using, for example, a single-screw extruder equipped with a cylinder (hereinafter, also simply referred to as "extruder").

[0077] The set temperature T1 of the cylinder in the kneading step may be 290°C or higher and 350°C or lower.

[0078] In the kneading step, a step of adding a blowing agent to the kneaded mixture containing the polyester resin (A), the polyimide resin (B), the polyphenylene ether resin (C), and the phosphorus-based flame retardant (a blowing agent adding step) may be further carried out. The addition of the blowing agent may be carried out, for example, by forcing the mixture into an extruder.

[0079] The foaming agent is preferably a hydrocarbon from the viewpoint of obtaining excellent processability by secondary or tertiary foaming, etc. On the other hand, the foaming agent is preferably carbon dioxide from the viewpoint of obtaining excellent flame retardancy.

[0080] The amount of the foaming agent to be added is not particularly limited, but may be, for example, 0.05 parts by mass or more and 10 parts by mass or less with respect to 100 parts by mass of the kneaded product.

[0081] The foaming granulation step may be carried out, for example, by extrusion foaming (primary foaming) from each nozzle of a multi-nozzle nozzle mold attached to the tip of an extruder.

[0082] The resin temperature T2 of the molten mixture in the expansion granulation step may be 260°C or higher and 350°C or lower. From the viewpoint of obtaining good expandability, the resin temperature T2 is preferably lower than the cylinder set temperature T1, more preferably 5 to 30°C lower than the cylinder set temperature T1. The resin temperature T2 can be made lower than the cylinder set temperature T1 in the kneading step by lowering the cylinder set temperature after the kneading step. Furthermore, when the extruder is a tandem extruder, the kneading step is performed in the first-stage extruder and the molten mixture is cooled in the second-stage extruder, thereby making the resin temperature T2 lower than the cylinder set temperature T1 in the kneading step. The resin temperature T2 can be measured using a thermocouple placed on a breaker plate inserted between the extruder and a die attached to the tip of the extruder.

[0083] In the expansion granulation step, a step (cutting step) may be carried out in which the expanded molten kneaded product is cut into particles to obtain expanded polyester resin particles. The cutting method is not particularly limited, but may be carried out, for example, by providing a rotary blade near the outlet of the nozzle mold and cutting the extruded foamed resin with the rotary blade.

[0084] The method for producing expanded polyester resin beads according to this embodiment may include a step of cooling the expanded polyester resin beads obtained in the cutting step (cooling step) and a step of drying the cooled expanded polyester resin beads (drying step). The cooling step may be carried out, for example, by impregnating the expanded polyester resin beads with cooling water. The drying step may be carried out, for example, by leaving the expanded polyester resin beads at room temperature or by leaving the expanded polyester resin beads under reduced pressure.

[0085] The present invention includes the following aspects. [1] A polyester-based resin foam particle composed of a flame-retardant resin composition containing a thermoplastic resin and a phosphorus-based flame retardant, The flame-retardant resin composition contains a polyester-based resin, a polyimide-based resin, and a polyphenylene ether-based resin, The content of the polyimide resin is 10% by mass or more and 30% by mass or less, The content of the polyphenylene ether resin is 3% by mass or more and 15% by mass or less, The content of the phosphorus-based flame retardant is 3% by mass or more and 10% by mass or less. Polyester resin foam particles. [2] The melt mass flow rate of the polyphenylene ether resin is 1 g / 10 min or more and 6 g / 10 min or less. [1] The polyester-based resin foam particles according to the present invention. [3] The mass average molecular weight of the polyphenylene ether resin is 50×10 3 Over 100 x 10 3 Below is the [1] or [2], wherein the polyester resin foam particles are [4] a matrix-domain structure is formed, the matrix phase including the polyester-based resin and the domain phase including the polyphenylene ether-based resin; The expanded polyester resin particles according to any one of [1] to [3]. [5] The flame-retardant resin composition further contains a crosslinking agent, At least a part of the polyester resin is a crosslinked polyester resin crosslinked with the crosslinking agent. The expanded polyester resin particles according to any one of [1] to [4]. [6] The flame-retardant resin composition further contains a foaming agent. The expanded polyester resin particles according to any one of [1] to [5]. [7] The blowing agent is a hydrocarbon. [6] The polyester-based resin foam particles according to [6]. [8] A molded article comprising a plurality of expanded particles containing a thermoplastic resin, the expanded particles being heat-fused to one another, A molded article, wherein the expanded beads are the expanded polyester resin beads according to any one of [1] to [7]. [9] melt-kneading a polyester resin, a polyimide resin, a polyphenylene ether resin, a phosphorus-based flame retardant, and a foaming agent; and foaming and granulating the melt-kneaded product obtained by the melt-kneading, The content of the polyimide resin is 10% by mass or more and 30% by mass or less, The content of the polyphenylene ether resin is 3% by mass or more and 15% by mass or less, A method for producing expanded polyester resin beads, in which the content of the phosphorus-based flame retardant is 3% by mass or more and 10% by mass or less.

[10] The method for producing expanded polyester resin particles according to [9], wherein the blowing agent is carbon dioxide.

[0086] The expanded polyester resin beads, molded articles, and methods for producing expanded polyester resin beads according to the present invention are not limited to the above-described embodiments, and various modifications are possible without departing from the spirit of the present invention. Furthermore, configurations, methods, etc. of embodiments other than those described above may be arbitrarily adopted and combined, and configurations, methods, etc. of one embodiment described above may be applied to configurations, methods, etc. of other embodiments described above. [Example]

[0087] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0088] The components used in each of the examples and comparative examples are shown below. <Polyester resin (A)> PET(A): Polyethylene terephthalate resin (manufactured by Lotte Chemical Co., Ltd., product name "BCB80") <Polyimide resin (B)> PEI (B1): Polyetherimide resin (SABIC Innovative Plastics, product name "Ultem1000") PEI (B2): Polyetherimide resin (SABIC Innovative Plastics, product name "Ultem1010") <Polyphenylene ether resin (C)> PPE(C): Polyphenylene ether resin (SABIC Innovative Plastics, product name "Noryl 646"; melt mass-flow rate in pelletized state: 2.8 g / 10 min; mass-average molecular weight in pelletized state: 67 × 103 ) <Phosphorus-based flame retardants> Flame retardant: Organophosphorus flame retardant (Teijin, product name "Fireguard FCX-210") <Other ingredients> Crosslinker: Pyromellitic anhydride Bubble nucleating agent: talc Blowing agent 1: Butane (isobutane: normal butane = 35:65 (mass ratio)) Blowing agent 2: Carbon dioxide

[0089] Example 1 <Preparation of flame retardant masterbatch> 80% by mass of PET (A) and 20% by mass of a flame retardant were melt-kneaded in a 30 mm twin-screw extruder to prepare a flame retardant masterbatch.

[0090] <Preparation of polyphenylene ether resin pellets> PPE (C) (powder form) was melted in a 30 mm twin-screw extruder to prepare resin pellets, which were used as PPE (C) in the preparation of expanded polyester resin beads described below.

[0091] <Preparation of Polyester-Based Resin Expanded Beads> The components listed in Table 1, except for the foaming agent, were fed into a single-screw extruder (hereinafter simply referred to as the "extruder") with a cylinder diameter D of 65 mm and a cylinder length L ratio of 34. The components were melt-kneaded at 300°C to produce a kneaded mixture. 1.36 parts by mass of the foaming agent listed in Table 1 per 100 parts by mass of the kneaded mixture was fed midway through the extruder by pressure injection into the molten mixture, resulting in uniform dispersion throughout the kneaded mixture to produce a foamable resin composition. The temperature of the molten foamable resin composition (extrusion resin temperature) was then raised to 290°C at the front end of the extruder, and the foamable resin composition was extruded and foamed through each nozzle of a multi-nozzle nozzle die (Φ0.8 × 50 holes) attached to the front end of the extruder. The extrusion rate of the foamable resin composition was 36 kg / h. The nozzle die used had nozzles positioned at equal intervals on a virtual circle with a diameter of 139.5 mm. Two rotary blades attached to a rotating shaft were rotated while pressed against the nozzle mold, and the expandable resin extruded from each nozzle was expanded (primary expansion) while being cut to form expanded beads. The rotation speed of the rotary blades was 3425 rpm. The cut expandable resin (expanded beads) was cooled with cooling water circulating through the inner wall of a chamber arranged to cover the mold, and then dehydrated to obtain expanded polyester resin beads.

[0092] <Preparation of molded body> The resulting polyester resin foam particles were left at room temperature for one week to form pre-expanded particles. The pre-expanded particles were placed in a mold consisting of a male and female mold with a flat rectangular internal space measuring 300 mm x 400 mm x 11 mm. Using a high-pressure molding machine, steam was first introduced from the female mold side to a pressure of 0.50 MPa (gauge pressure) for 30 seconds to create a pressure of 0.10 MPa inside the mold. Steam was then introduced from the male mold side for 30 seconds to create a pressure of 0.10 MPa inside the mold. Steam was then introduced from both the male and female mold sides for 30 seconds to create a pressure of 0.20 MPa inside the mold. After heating for 30 seconds, cooling water was sprayed into the mold to cool it down, and the molded plate was removed. The mold was then dried in a 60°C oven for 10 hours to produce a molded product.

[0093] Example 2 Polyester-based resin expanded beads and a molded article were produced in the same manner as in Example 1, except that the blending amounts of each component were as shown in Table 1 and the extrusion resin temperature was 285°C.

[0094] Example 3 Polyester-based resin expanded beads and a molded article were prepared in the same manner as in Example 1, except that the blending amounts of each component were as shown in Table 1.

[0095] (Comparative Example 1) Polyester-based resin foamed beads and a molded article were produced in the same manner as in Example 1, except that the blending amounts of each component were as shown in Table 1 and the extrusion resin temperature was 300°C.

[0096] <Melt mass-flow rate (MFR)> The melt mass flow rate (MFR) of the polyphenylene ether resin (C) was measured under the following conditions using a "Melt Flow Index Tester (Automatic) 120-SAS" manufactured by Yasuda Seiki Seisakusho Co., Ltd., based on Method B b) of JIS K7210-1:1999 "Plastics - Determination of melt mass flow rate (MFR) and melt volume flow rate (MVR) of thermoplastic plastics - Part 1", under the following conditions: Sample: 3g to 8g Preheat (1): 200 seconds Preheat (2): 30 seconds Test temperature: 300℃ Test load: 49.03N Piston travel distance (interval): 25mm The polyphenylene ether resin (C) was dried in a vacuum dryer at 90°C for 3 hours, and then the test was carried out three times using the above measurement method. The average of the obtained values ​​was used as the melt mass-flow rate (MFR) of the polyphenylene ether resin (C).

[0097] <Mass average molecular weight> The mass average molecular weight of the polyphenylene ether resin (C) was measured by the following method. 15 mg of sample was taken, 6 mL of chloroform was added, and the mixture was gently shaken manually. This was left for an immersion time of 6 ± 1.0 hours. After confirming that the sample was completely dissolved, it was filtered through a non-aqueous 0.45 μm chromatodisc manufactured by GL Sciences Inc. or a non-aqueous 0.45 μm syringe filter manufactured by Shimadzu GLC Corporation to prepare a measurement sample. The measurement sample was measured using a chromatograph under the following measurement conditions, and the mass average molecular weight of the sample was determined from a previously prepared standard polystyrene calibration curve. [Measuring equipment] Measurement equipment: Tosoh Corporation's "HLC-8320GPC EcoSEC" gel permeation chromatograph (with built-in RI and UV detectors) [GPC measurement conditions] ·column <Sample side> Guard column: Tosoh Corporation TSK guard column HXL-H (6.0 mm x 4.0 cm) x 1 Measurement column: Tosoh Corporation TSKgel GMHXL (7.8 mm I.D. x 30 cm) x 2 in series <Reference side> Resistance tube (inner diameter 0.1 mm x 2 m) x 2 in series Column temperature: 40℃ Mobile phase: chloroform <Mobile phase flow rate> Sample pump: 1.0 mL / min Reference pump: 0.5 mL / min Detector: RI detector Injection volume: 50μL Measurement time: 25 minutes Sampling pitch: 500 ms

[0098] The standard polystyrene samples used for the calibration curve were "STANDARD SM-105" and "STANDARD SH-75" manufactured by Showa Denko K.K., with mass average molecular weights of 5,620,000, 3,120,000, 1,250,000, 442,000, 151,000, 53,500, 17,000, 7,660, 2,900, and 1,320. The polystyrene standards for the calibration curve were divided into groups A (5,620,000, 1,250,000, 151,000, 17,000, 2,900) and B (3,120,000, 442,000, 53,500, 7,660, 1,320). A was weighed (2 mg, 3 mg, 4 mg, 4 mg, 4 mg) and dissolved in 30 mL of chloroform. B was weighed (3 mg, 4 mg, 4 mg, 4 mg, 4 mg) and dissolved in 30 mL of chloroform. A calibration curve (cubic equation) was prepared from the retention times obtained after measuring 50 μL of each of the prepared solutions A and B. The mass-average molecular weight was calculated using this calibration curve.

[0099] <Bulk density of expanded polyester resin beads> The bulk density of the expanded polyester resin particles was measured in accordance with JIS K6911:1995 "General testing methods for thermosetting plastics." Measurement was performed using an apparent density measuring device in accordance with JIS K6911, and the bulk density of the expanded particles was calculated based on the following formula (s1). Bulk density of polyester resin foam particles (g / cm 3 ) = [mass of the measuring cylinder containing the polyester resin foam particles (g) - mass of the measuring cylinder (g)] / [capacity of the measuring cylinder (cm 3 )]···(s1)

[0100] <Open cell ratio of expanded polyester resin beads> The open cell ratio of the expanded polyester resin particles was measured by the following method. First, a sample cup for a volumetric air comparison hydrometer was prepared, and the total mass a (g) of the expanded polyester resin particles was measured to fill about 80% of the sample cup. Next, the total volume b (cm 3 ) was measured using a hydrometer at 1-1 / 2-1 atmospheres. The measurement was performed using a Tokyo Science "Volumetric Air Comparison Hydrometer Model 1000." A wire mesh container was prepared, and the wire mesh container was immersed in water, and the mass c (g) of the wire mesh container while immersed in water was measured. All of the expanded polyester resin particles were placed in the wire mesh container, and the wire mesh container was immersed in water, and the combined mass d (g) of the wire mesh container while immersed in water and the total amount of expanded polyester resin particles placed in the wire mesh container was measured. The masses of the expanded polyester resin particles and the wire mesh container were measured using an electronic balance HB3000 (minimum scale 0.01 g) manufactured by Yamato Seisei Co., Ltd. The apparent volume e (cm ) of the expanded polyester resin particles was calculated based on the following formula: 3 ) is calculated, and the apparent volume e and the total volume b (cm 3 The open cell ratio of the expanded polyester resin beads was calculated using the following formula (s2) based on the above formula. 3 In this measurement, the expanded polyester resin particles were stored in advance for 16 hours in an environment of JIS K7100-1999, symbol 23 / 50, grade 2, and then the measurement was carried out in the same environment. Open cell ratio (%) = 100 × (eb) / e (s2) (e=a+(cd))

[0101] <Density of molded body> The density of the molded body was measured by the method described in JIS K7222:1999 "Foamed plastics and rubber - Measurement of apparent density". 3 The above molded body was cut without changing the original cell structure of the material, and the mass was measured. The density was calculated using the following formula (s3). Density (g / cm 3 ) = mass of compact (g) / volume of compact (cm 3 )···(s3)

[0102] <Flame retardancy of molded products> The flame retardancy of the molded articles was measured in accordance with the method described in the vertical flame test (V) in UL94:1996. Test pieces measuring 125 mm long, 13 mm wide, and 11 mm thick (with a skin layer only in the thickness direction) were cut from the molded articles obtained in each Example and Comparative Example, measuring 300 mm long, 400 mm wide, and 11 mm high, and used for measurement. The test pieces were conditioned under the conditions of ASTM D618 before use. Measurements were performed in an environment with a temperature of 10 to 35°C and a humidity of 45 to 75%, and the flame retardancy was evaluated according to the vertical flame test (V) described in UL94:1996.

[0103] The results of each example and comparative example are shown in Table 1.

[0104] [Table 1]

[0105] As can be seen from the results in Table 1, in each of the Examples which satisfied all of the constituent requirements of the present invention, the flammability of the molded articles was better than that of the Comparative Examples.

[0106] The molded articles of each of the examples and comparative examples were observed using a transmission electron microscope (TEM) under the following measurement conditions. A section was cut from near the center of a single foam bead. The section was embedded in epoxy resin. The epoxy resin was cured at 60°C for 24 hours to produce a cured product. The cured product was sliced ​​using a Leica EM UC7 ultramicrotome manufactured by Leica Microsystems, Inc., to prepare ultrathin sections (70 nm thick). The ultrathin sections were then stained with ruthenium tetroxide. The ultrathin sections were photographed using a Hitachi High-Technologies Corporation HT7800 transmission electron microscope and a Hitachi High-Technologies Corporation RC16M camera.

[0107] 1A to 1F show enlarged cross-sectional views of the molded body of Example 1 obtained by TEM observation, and FIGS. 2A to 2F show enlarged cross-sectional views of the molded body of Comparative Example 1 obtained by TEM observation.

[0108] 1A to 1F, it can be seen that a matrix-domain structure having a matrix phase MT1 containing a polyethylene terephthalate resin, which is a polyester resin, and a domain phase DM1 containing a polyphenylene ether resin is formed in the molded article of Example 1. Furthermore, the domain phase DM1 is formed bulky. 2A to 2F, it can be seen that a matrix-domain structure having a matrix phase MT2 containing a polyethylene terephthalate resin, which is a polyester resin, and a domain phase DM2 containing a polyetherimide resin is formed in the molded article of Comparative Example 1. Furthermore, the domain phase DM2 is formed finely and uniformly dispersed in the matrix phase MT2. Due to the difference in structure as described above, it can be seen that the matrix-domain structure of Example 1, which has a domain phase DM1 containing a polyphenylene ether resin, is advantageous in terms of excellent flame retardancy.

[0109] From the above, it can be seen that the present invention can provide expanded polyester resin beads, molded articles, and a method for producing expanded polyester resin beads, all of which are excellent in flame retardancy. [Explanation of symbols]

[0110] MT1...matrix phase containing polyethylene terephthalate resin, DM1...domain phase containing polyphenylene ether resin, MT2...matrix phase containing polyethylene terephthalate resin, DM2...domain phase containing polyetherimide resin.

Claims

1. A polyester-based resin foam particle composed of a flame-retardant resin composition containing a thermoplastic resin and a phosphorus-based flame retardant, The flame-retardant resin composition contains a polyester-based resin, a polyimide-based resin, and a polyphenylene ether-based resin, The content of the polyimide resin is 10% by mass or more and 30% by mass or less, The content of the polyphenylene ether resin is 3% by mass or more and 15% by mass or less, The content of the phosphorus-based flame retardant is 3% by mass or more and 10% by mass or less. Polyester resin foam particles.

2. The melt mass flow rate of the polyphenylene ether resin is 1 g / 10 min or more and 6 g / 10 min or less. The expanded polyester resin particles according to claim 1.

3. The mass average molecular weight of the polyphenylene ether resin is 50×10 ３ Above 100 x 10 ３ Below is the The expanded polyester resin particles according to claim 1.

4. a matrix-domain structure is formed, the matrix phase including the polyester-based resin and the domain phase including the polyphenylene ether-based resin; The expanded polyester resin particles according to claim 1.

5. The flame-retardant resin composition further contains a crosslinking agent, At least a part of the polyester resin is a crosslinked polyester resin crosslinked with the crosslinking agent. The expanded polyester resin particles according to claim 1.

6. The flame-retardant resin composition further contains a foaming agent. The expanded polyester resin particles according to claim 1.

7. The blowing agent is a hydrocarbon. The expanded polyester resin particles according to claim 6.

8. A molded article comprising a plurality of expanded particles containing a thermoplastic resin, the expanded particles being heat-fused to one another, A molded article, wherein the expanded beads are the expanded polyester resin beads according to any one of claims 1 to 7.

9. melt-kneading a polyester resin, a polyimide resin, a polyphenylene ether resin, a phosphorus-based flame retardant, and a foaming agent; and foaming and granulating the melt-kneaded product obtained by the melt-kneading, The content of the polyimide resin is 10% by mass or more and 30% by mass or less, The content of the polyphenylene ether resin is 3% by mass or more and 15% by mass or less, The method for producing expanded polyester resin particles includes producing expanded polyester resin particles having a phosphorus-based flame retardant content of 3% by mass or more and 10% by mass or less.

10. The method for producing expanded polyester resin particles according to claim 9, wherein the blowing agent is carbon dioxide.

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