Aromatic polyester-based resin foam particle, and foam molding

Abstract

To provide foam particles which enable production of a foam molding excellent in a compressive modulus of elasticity, and are expanded at a high expansion ratio.SOLUTION: The present invention relates to: foam particles which are aromatic polyester-based resin foam particles containing a zinc element, wherein the content of the zinc element is 0.0015 mass% or more and 0.0025 mass% or less of the foam particles; and a foam molding, wherein the content of the zinc element is 0.0010 mass% or more and 0.0022 mass% or less of the foam molding, and the density is 0.03 g / cm3 or more and 0.140 g / cm3 or less.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to expanded aromatic polyester resin beads and a foamed molded article. [Background technology]

[0002] Foamed molded articles are widely used because of their advantages, such as light weight and excellent heat insulation. Foamed bead molding is a method of producing a foamed molded article conforming to the shape of the mold by filling a molding die with expanded beads, heating, expanding, and fusing the expanded beads together (Patent Document 1). One method of producing expanded beads involves feeding a raw aromatic polyester resin into an extruder, melt-kneading the resin in the presence of a blowing agent, and extruding the molten mixture cooled to about 280°C through a nozzle die attached to the front end of the extruder to produce expanded, strand-shaped aromatic polyester resin extrudates, which are then cut into particles using a pelletizer or the like to produce expanded aromatic polyester resin beads. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2001-329102 Summary of the Invention [Problem to be solved by the invention]

[0004] In this manufacturing method, if the molten resin is extruded and foamed at the melt-kneading temperature (approximately 300°C), open cells will form in the foamed beads. To prevent this, a step of cooling the molten resin to approximately 280°C before extrusion foaming has been added. However, adding the cooling step shortens the extrusion foaming time, making it difficult to obtain foamed beads that have been expanded at a high expansion ratio. [Means for solving the problem]

[0005] As a result of extensive research, the present inventors have found that by further heating expanded beads (primary expanded beads) produced by extrusion foaming with steam to induce secondary expansion using the force of the blowing agent remaining in the expanded beads, aromatic polyester resin expanded beads (secondary expanded beads) can be obtained with a high expansion ratio, i.e., low density. These secondary expanded beads contain a specific amount of zinc element, and the aromatic polyester resin foam molded article obtained by in-mold foaming of these secondary expanded beads has an excellent compressive modulus. Here, steam heating for secondary expansion softens the base resin of the expanded beads, causing the secondary expanded beads to bond together, resulting in bonded particles. Therefore, the present inventors have further found that the formation of bonded particles can be suppressed by applying a bonding inhibitor (especially zinc stearate) to the primary expanded beads before steam heating.

[0006] The present invention typically includes the following aspects. Section 1. Expanded aromatic polyester resin particles containing zinc element, Expanded particles, the zinc content of which is 0.0015% by mass or more and 0.0025% by mass or less of the expanded particles. Section 2. The average particle size is 2.60 mm or more and 3.50 mm or less, and the bulk density is 0.03 g / cm 3 More than 0.120g / cm 3 Item 1, wherein the expanded particles are: Section 3. Item 3. The expanded aromatic polyester resin beads according to item 1 or 2, wherein the expanded aromatic polyester resin beads contain polyethylene terephthalate in an amount of 80% by mass or more. Section 4. A zinc-containing aromatic polyester resin foam molded article, The zinc element content of the foamed molded product is 0.0010 mass% or more and 0.0022 mass% or less, and the density is 0.03 g / cm 3 More than 0.140g / cm 3 A foam molded article as follows: Section 5. Item 5. The foam molded article according to item 4, wherein the aromatic polyester resin foam molded article contains polyethylene terephthalate in an amount of 80% by mass or more. [Effects of the Invention]

[0007] According to the present invention, it is possible to provide low-density expanded aromatic polyester resin beads that can give an expanded molded aromatic polyester resin article having good fusion between the expanded beads and excellent mechanical properties. According to the present invention, it is possible to provide an aromatic polyester resin foam molded article in which the foamed particles are well fused to each other and which has excellent mechanical properties. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a schematic cross-sectional view showing an example of an apparatus for producing expanded aromatic polyester resin beads. [Figure 2] FIG. 2 is a schematic front view of a nozzle die. [Figure 3] 1 is a schematic diagram showing a state in which expanded aromatic polyester resin particles enter cooling water. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0009] As used herein, the phrase "comprising" is intended to encompass the phrases "consisting essentially of" and "consisting of."

[0010] In the numerical ranges described in stages in this specification, the upper or lower limit of a numerical range in a certain stage can be arbitrarily combined with the upper or lower limit of a numerical range in the same stage or in another stage. In addition, in the numerical ranges described in this specification, the upper or lower limit of the numerical range may be replaced with a value shown in an example or a value that can be unambiguously derived from an example.

[0011] In this specification, numerical values ​​connected with "to" indicate a numerical range that includes the numerical values ​​before and after "to" as the lower and upper limits. For example, "1 to 10% by mass" is equivalent to "1% by mass or more and 10% by mass or less."

[0012] In this specification, with regard to numerical ranges, "to" means equal to or greater than the leftmost numerical value and equal to or less than the rightmost numerical value. For example, "0.5 to 10% by mass" and "0.5% to 10% by mass" both mean "0.5% by mass or greater and 10% by mass or less." Furthermore, with regard to numerical ranges, "equal to or greater than" means "the same as or greater than," and "equal to or less than" means "the same as or less than."

[0013] (Aromatic polyester resin foam particles) The expanded aromatic polyester resin particles may contain the aromatic polyester resin in an amount of 80% by mass or more, 90% by mass or more, 95% by mass or more, 98% by mass or more, 99% by mass or more, 80 to 99.5% by mass, 80 to 99% by mass, 80 to 98% by mass, 80 to 95% by mass, 80 to 90% by mass, 90 to 99.5% by mass, 90 to 99% by mass, 90 to 98% by mass, 90 to 95% by mass, etc. The aromatic polyester resin may contain polyethylene terephthalate in an amount of 80% by mass or more, 90% by mass or more, 95% by mass or more, 98% by mass or more, 99% by mass or more.

[0014] (aromatic polyester resin) The aromatic polyester resin is a polyester containing an aromatic dicarboxylic acid component and a diol component. Examples of the aromatic polyester resin include polyethylene terephthalate, polypropylene terephthalate, polybutylene terephthalate, polycyclohexanedimethylene terephthalate, polyethylene naphthalate, and polybutylene naphthalate. Polyethylene terephthalate and polyethylene naphthalate are preferred, and a combination of polyethylene terephthalate and polyethylene naphthalate is more preferred. The aromatic polyester resin may be used alone or in combination of two or more.

[0015] Polyethylene naphthalate is generally an aromatic linear polyester obtained by condensing ethylene glycol with naphthalenedicarboxylic acid or dimethyl naphthalate. Polyethylene naphthalate generally has a high molecular weight. In the polyethylene naphthalate, both naphthalenedicarboxylic acid and dimethyl naphthalate may be used. Only one type of polyethylene naphthalate may be used, or two or more types may be used in combination.

[0016] The naphthalenedicarboxylic acid is preferably 2,6-naphthalenedicarboxylic acid. Other naphthalenedicarboxylic acids include 2,7-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, 1,6-naphthalenedicarboxylic acid, and 1,7-naphthalenedicarboxylic acid.

[0017] The polyethylene naphthalate may contain a trivalent or higher alcohol. The polyethylene naphthalate may contain a trivalent or higher carboxylic acid. The content of the trivalent or higher alcohol and the content of the trivalent or higher carboxylic acid in the polyethylene naphthalate are preferably small. In 100 mol% of the polyethylene naphthalate, the content of the trivalent or higher alcohol and the content of the trivalent or higher carboxylic acid are preferably less than 15 mol% each.

[0018] Examples of the trihydric or higher alcohol include glycerin, pentaerythritol, etc. Only one type of the trihydric or higher alcohol may be used, or two or more types may be used in combination. Examples of trivalent or higher carboxylic acids include trimellitic acid, pyromellitic acid, etc. Only one type of trivalent or higher carboxylic acid may be used, or two or more types may be used in combination.

[0019] When polyethylene naphthalate and polyethylene terephthalate are contained in expanded aromatic polyester resin beads, the content of polyethylene naphthalate in the expanded beads is preferably 1% by mass or more and 10% by mass or less, and more preferably 3% by mass or more and 8% by mass or less, relative to the mass of the expanded beads, in order to provide an expanded molded article having a thin wall with excellent dimensional accuracy and excellent bending properties.

[0020] Polyethylene terephthalate is generally an aromatic linear polyester obtained by condensing ethylene glycol with terephthalic acid or dimethyl terephthalate. Polyethylene terephthalate generally has a high molecular weight. In the polyethylene terephthalate, both terephthalic acid and dimethyl terephthalate may be used. Only one type of polyethylene terephthalate may be used, or two or more types may be used in combination.

[0021] The polyethylene terephthalate may contain a polyhydric alcohol. The polyethylene terephthalate may contain a polycarboxylic acid. In 100 mol % of the polyethylene terephthalate, the content of the polyhydric alcohol and the content of the polycarboxylic acid are each preferably less than 15 mol %.

[0022] Examples of polyhydric alcohols that may be contained in polyethylene terephthalate include the compounds exemplified as trihydric polyhydric alcohols that may be contained in polyethylene naphthalate. Only one type of polyhydric alcohol may be used, or two or more types may be used in combination. Examples of polycarboxylic acids that may be contained in polyethylene terephthalate include the compounds exemplified as tricarboxylic acids that may be contained in polyethylene naphthalate. The polycarboxylic acids may be used alone or in combination of two or more.

[0023] When polyethylene naphthalate and polyethylene terephthalate are contained in expanded aromatic polyester resin beads, the content of polyethylene terephthalate in the expanded beads is preferably 90% by mass or more and 99% by mass or less, and more preferably 92% by mass or more and 97% by mass or less, relative to the mass of the expanded beads, in order to provide an expanded molded article having a thin-walled shape with excellent dimensional accuracy and excellent bending properties of the expanded molded article.

[0024] When polyethylene naphthalate and polyethylene terephthalate are contained in the expanded aromatic polyester resin particles, the total content of polyethylene naphthalate and polyethylene terephthalate may be 80% by mass or more and 100% by mass or less, based on the mass of the expanded particles. In order to achieve excellent dimensional accuracy of a thin-walled expanded molded article and excellent bending properties of the expanded molded article, the total content of polyethylene naphthalate and polyethylene terephthalate is preferably 90% by mass or more and 100% by mass or less, and more preferably 91% by mass or more and 100% by mass or less.

[0025] When polyethylene naphthalate and polyethylene terephthalate are contained in the expanded aromatic polyester resin beads, the mass ratio of polyethylene naphthalate to polyethylene terephthalate in the expanded aromatic polyester resin beads is preferably 1:99 to 10:90, and more preferably 3:97 to 8:92, in order to provide a thin-walled expanded molded article with excellent dimensional accuracy and excellent bending properties.

[0026] When polyethylene naphthalate and polyethylene terephthalate are contained in the expanded aromatic polyester resin particles, the expanded particles may contain other aromatic polyester resins. The other aromatic polyester resins may be the aromatic polyester resins exemplified above. The content of the other aromatic polyester resins in the expanded aromatic polyester resin particles may be 0% by mass or more and 9% by mass or less, preferably 0% by mass or more and 5% by mass or less, and more preferably 0% by mass, i.e., no other aromatic polyester resins are contained, relative to the mass of the expanded particles.

[0027] The aromatic polyester resin may be not only a petroleum-derived product, but also a plant-derived product or a recycled product recovered and regenerated from used PET bottles or the like.

[0028] The aromatic polyester resin constituting the expanded aromatic polyester resin particles may be crosslinked with a crosslinking agent. Examples of the crosslinking agent include acid dianhydrides such as pyromellitic anhydride, polyfunctional epoxy compounds, oxazoline compounds, and oxazine compounds. The crosslinking agents may be used alone or in combination of two or more.

[0029] When the aromatic polyester resin is modified by crosslinking with a crosslinking agent, the aromatic polyester resin and the crosslinking agent are supplied to an extruder during the production of expanded aromatic polyester resin particles, and the aromatic polyester resin is crosslinked with the crosslinking agent in the extruder. The amount of the crosslinking agent supplied to the extruder is preferably 0.01 to 5 parts by mass, more preferably 0.1 to 1 part by mass, per 100 parts by mass of the aromatic polyester resin, from the viewpoint of performing extrusion foaming well.

[0030] The mass average molecular weight of the aromatic polyester resin constituting the expanded beads of the present invention is preferably 45,000 to 100,000, more preferably 60,000 to 90,000, in order to provide excellent extrusion foamability and excellent secondary foamability of the resulting expanded beads.

[0031] The expanded aromatic polyester resin particles may have an average particle size of 2.60 to 3.50 mm. The average particle size is preferably 2.70 to 3.50 mm, and more preferably 2.80 to 3.50 mm. An average particle size within this range is advantageous in terms of the light weight of the resulting foamed molded article and its filling properties during molding.

[0032] The average particle size of the expanded aromatic polyester resin particles was measured by sieving 50 g of the expanded particles through several sieves with different mesh sizes specified in JIS (mesh size 6.70 mm, 5.60 mm, 4.75 mm, 4.00 mm, 3.35 mm, 2.80 mm, 2.36 mm, 2.00 mm, 1.70 mm, 1.40 mm, 1.18 mm, 1.00 mm, 0.850 mm, 0.710 mm, 0.600 mm, 0.500 mm) in order from the largest mesh size to the smallest mesh size. Depending on the particle size, the expanded particles will not be able to pass through the sieves with the specified mesh size and will remain on each sieve. The average particle size of the expanded particles remaining on each sieve is determined based on the size of the sieve openings, as shown in the following table. For example, the particle size of the expanded particles remaining on a sieve with an opening size of 1.70 mm is set to 1.85 mm.

[0033] [Table 1]

[0034] The expanded aromatic polyester resin particles may contain elemental zinc. The amount of elemental zinc contained in the expanded aromatic polyester resin particles may be 0.0015 to 0.0025 mass%, preferably 0.0016 to 0.0025 mass%, more preferably 0.0016 to 0.0024 mass%, and even more preferably 0.0017 to 0.0024 mass%, of the mass of the expanded aromatic polyester resin particles. The elemental zinc contained in the expanded aromatic polyester resin particles may be elemental zinc derived from zinc stearate. The amount of elemental zinc contained in the expanded particles may be determined by ashing the expanded particles, mixing the resulting ash with concentrated hydrochloric acid, filtering off the insoluble matter in the mixture, and measuring the amount of elemental zinc in the resulting filtrate by ICP atomic emission spectrometry. Specifically, the amount may be determined by the method described in the Examples.

[0035] The bulk density of the expanded aromatic polyester resin particles is 0.03 g / cm from the viewpoint of improving the expansion power and the fusion power of the secondary expanded particles. 3 More than 0.120g / cm3 Preferably less than 0.04 g / cm 3 More than 0.120g / cm 3 Less than 0.04 g / cm is more preferable. 3 More than 0.110g / cm 3 The following are particularly preferred. The bulk density of the expanded aromatic polyester resin beads can be adjusted by the extrusion pressure of the raw material resin at the nozzle outlet of the nozzle mold or the amount of blowing agent. The extrusion pressure of the raw material resin at the nozzle outlet of the nozzle mold can be adjusted by the nozzle diameter, extrusion rate, and melt viscosity of the aromatic polyester resin. The bulk density of the expanded aromatic polyester resin beads is measured in accordance with JIS K6911:1995 "General Test Methods for Thermosetting Plastics." In detail, it is determined by the method described in the Examples.

[0036] (Method of manufacturing expanded aromatic polyester resin beads) The expanded beads of the present invention can be produced by a process that includes, for example, a step of feeding an aromatic polyester resin and, if necessary, a crosslinking agent into an extruder and melt-kneading them in the presence of a blowing agent to prepare a melt-kneaded mixture; a primary expansion step of extruding and foaming the melt-kneaded mixture, preferably under gaseous conditions, to prepare an extruded foam; a cutting step of cutting the extruded foam to prepare primary foamed beads; a debonding agent spreading step of spreading zinc stearate on the surfaces of the primary foamed beads; and a secondary expansion step of heating the primary foamed beads with the zinc stearate spread thereon with steam (preferably water vapor) to foam them to prepare secondary foamed beads. The present invention may include this production method. In this production method, the cutting step may be a step of cutting the extruded foam into granular cut pieces and cooling the granular cut pieces with cooling water to prepare expanded beads. The explanations described above in the section on expanded aromatic polyester resin beads may be applied to this production method to the extent applicable.

[0037] An aromatic polyester resin, and optionally a crosslinking agent, are fed to an extruder and melt-kneaded in the presence of a foaming agent to prepare a melt-kneaded product. Crosslinking of the aromatic polyester resin can be carried out by a known method. For example, the aromatic polyester resin and the crosslinking agent are fed to an extruder and kneaded in the extruder, whereby the aromatic polyester resin can be crosslinked by the crosslinking agent. To ensure good extrusion foaming, the amount of crosslinking agent fed to the extruder is preferably 0.01 to 5 parts by mass, more preferably 0.1 to 1 part by mass, per 100 parts by mass of the aromatic polyester resin material.

[0038] The blowing agent may be an organic gas such as an aliphatic hydrocarbon having 3 to 6 carbon atoms, or an inorganic gas such as carbon dioxide, nitrogen, or air. The blowing agent may be used alone or in combination. The blowing agent is preferably an aliphatic hydrocarbon having 3 to 6 carbon atoms. Examples of the aliphatic hydrocarbon having 3 to 6 carbon atoms include propane, normal butane, isobutane, normal pentane, isopentane, and hexane, with normal butane and isobutane being preferred. The amount of the blowing agent used may be from 0.05 to 0.50 parts by mass, and more preferably from 0.05 to 0.40 parts by mass, per 100 parts by mass of the aromatic polyester resin, in terms of imparting the expansion force required for expansion molding to the expanded particles, providing a thin-walled foam with excellent dimensional accuracy, and providing the foam with excellent bending properties.

[0039] A cell control agent may be supplied to the extruder. Examples of such cell control agents include polytetrafluoroethylene powder, acrylic resin-modified polytetrafluoroethylene powder, and talc, with talc being more preferred. The amount of cell control agent supplied to the extruder is preferably 0.01 to 5 parts by mass, more preferably 0.05 to 3 parts by mass, and particularly preferably 0.1 to 2 parts by mass, per 100 parts by mass of the aromatic polyester resin.

[0040] The expanded aromatic polyester resin particles are preferably produced by extrusion foaming. For example, an aromatic polyester resin material is fed into an extruder and melt-kneaded in the presence of a foaming agent, and then the aromatic polyester resin extrudate is extruded from a nozzle die attached to the front end of the extruder and foamed while being cut with a rotary blade to produce primary foamed particles, zinc stearate is spread on the surfaces of the primary foamed particles, and the primary foamed particles with zinc stearate spread on their surfaces are heated with steam to foam, thereby producing expanded aromatic polyester resin particles.

[0041] The melt-kneaded mixture may be extruded and foamed, preferably under gaseous conditions, to prepare an extruded foam in a primary foaming step. The extruder may be any conventionally used extruder, and examples thereof include a single-screw extruder, a twin-screw extruder, and a tandem extruder in which a plurality of extruders are connected.

[0042] An example of a manufacturing apparatus used for manufacturing expanded aromatic polyester resin beads will be described. In FIG. 1, a nozzle die 1 is attached to the front end of an extruder. The nozzle die 1 is preferred because it can extrude and foam the aromatic polyester resin to form uniform, fine bubbles. As shown in FIG. 2, a plurality of nozzle outlets 11 are formed at equal intervals on the same imaginary circle A on the front end surface 1a of the nozzle die 2. The nozzle die attached to the front end of the extruder is not particularly limited as long as it does not cause the aromatic polyester resin to foam within the nozzle.

[0043] The number of nozzles in the nozzle mold 1 is preferably 8 to 50, more preferably 5 to 60, and particularly preferably 8 to 50. The diameter of the outlet portion 11 of the nozzle in the nozzle mold 1 is preferably 0.2 to 2 mm, more preferably 0.3 to 1.6 mm, and particularly preferably 0.4 to 1.2 mm. The length of the land portion of the nozzle mold 1 is preferably 1.5 to 30 times the diameter of the outlet portion 11 of the nozzle in the nozzle mold 1, and more preferably 2 to 20 times.

[0044] In the portion of the front end surface 1a of the nozzle mold 1 surrounded by the nozzle outlet portion 11, a rotating shaft 2 is arranged so as to protrude forward, and this rotating shaft 2 passes through the front portion 41a of a cooling drum 41 that constitutes the cooling member 4 described later, and is connected to a driving member 3 such as a motor.

[0045] Furthermore, one or more rotary blades 5 are integrally provided on the outer peripheral surface of the rear end of the rotary shaft 2, and all of the rotary blades 5 are constantly in contact with the front end surface 1a of the nozzle die 1 during rotation. When multiple rotary blades 5 are integrally provided on the rotary shaft 2, the multiple rotary blades 5 are arranged at equal intervals in the circumferential direction of the rotary shaft 2. Moreover, FIG. 2 shows, as an example, a case where four rotary blades 5 are integrally provided on the outer peripheral surface of the rotary shaft 2.

[0046] As the rotary shaft 2 rotates, the rotary blade 5 moves on an imaginary circle A on which the nozzle outlet 11 is formed while constantly contacting the front end surface 1a of the nozzle mold 1, and is configured to be able to cut the aromatic polyester resin extrudate extruded from the nozzle outlet 11 in sequence and continuously.

[0047] A cooling member 4 is disposed so as to surround at least the front end of the nozzle die 1 and the rotary shaft 2. This cooling member 4 is equipped with a cylindrical cooling drum 41 with a bottom, which has a front part 41a that is circular in front view and has a larger diameter than the nozzle die 1, and a cylindrical peripheral wall part 41b that extends rearward from the outer periphery of this front part 41a.

[0048] Furthermore, a supply port 41c for supplying cooling water 42 is formed in a state penetrating from the inner to outer peripheral surfaces of the peripheral wall portion 41b of the cooling drum 41 in a portion corresponding to the outside of the nozzle die 1. A supply pipe 41d for supplying cooling water 42 into the cooling drum 41 is connected to the outer opening of the supply port 41c of the cooling drum 41.

[0049] The cooling water 42 is configured to be supplied obliquely forward through the supply pipe 41d along the inner circumferential surface of the circumferential wall 41b of the cooling drum 41. The cooling water 42 advances forward in a spiral along the inner circumferential surface of the circumferential wall 41b of the cooling drum 41 due to centrifugal force generated by the flow speed when the cooling water 42 is supplied from the supply pipe 41d to the inner circumferential surface of the circumferential wall 41b of the cooling drum 41. As the cooling water 42 advances along the inner circumferential surface of the circumferential wall 41b, the cooling water 42 gradually spreads in a direction perpendicular to the direction of advancement, so that the inner circumferential surface of the circumferential wall 41b forward of the supply port 41c of the cooling drum 41 is entirely covered with the cooling water 42.

[0050] A discharge port 41e is formed in the lower surface of the front end of the peripheral wall portion 41b of the cooling drum 41, penetrating from the inner to the outer circumferential surface thereof. A discharge pipe 41f is connected to the outer opening of the discharge port 41e. The expanded aromatic polyester resin particles and the cooling water 42 are configured to be continuously discharged through the discharge port 41e.

[0051] The aromatic polyester resin extrudate extruded and foamed from the nozzle die 1 subsequently enters a cutting process. The aromatic polyester resin extrudate is cut by rotating the rotary shaft 2, thereby rotating the rotary blade 5 disposed on the front end surface 1a of the nozzle die 1. The rotation speed of the rotary blade 5 is preferably 2000 rpm or more and 10000 rpm or less. It is preferable that the rotary blade is rotated at a constant rotation speed.

[0052] All of the rotary blades 5 rotate while constantly in contact with the front end face 1a of the nozzle die 1, and the aromatic polyester resin extrudate extruded and foamed from the nozzle die 1 is cut into granular cut pieces in the atmosphere at regular time intervals by shear stress generated between the rotary blades 5 and the edge of the nozzle outlet portion 11 of the nozzle die 1.

[0053] The aromatic polyester resin is prevented from foaming within the nozzle of the nozzle mold 1. The aromatic polyester resin is not yet foamed immediately after being discharged from the outlet 11 of the nozzle of the nozzle mold 1, and begins to foam a short time after being discharged. Therefore, the aromatic polyester resin extrudate consists of an unfoamed portion immediately after being discharged from the outlet 11 of the nozzle of the nozzle mold 1, and a foamed portion that is continuous with the unfoamed portion and is in the process of foaming, having been extruded prior to the unfoamed portion.

[0054] The unfoamed portion remains in this state from the time it is discharged from the nozzle outlet 11 of the nozzle mold 1 until foaming begins. The time for which this unfoamed portion remains can be adjusted by the resin pressure at the nozzle outlet 11 of the nozzle mold 1, the amount of foaming agent, and the like. If the resin pressure at the nozzle outlet 11 of the nozzle mold 1 is high, the aromatic polyester resin extrudate will not foam immediately after being extruded from the nozzle mold 1 and will remain in an unfoamed state. The resin pressure at the nozzle outlet 11 of the nozzle mold 1 can be adjusted by the nozzle diameter, extrusion rate, and the melt viscosity and melt tension of the aromatic polyester resin. By adjusting the amount of foaming agent to an appropriate amount, foaming of the aromatic polyester resin inside the mold can be prevented, and an unfoamed portion can be reliably formed.

[0055] Since all of the rotary blades 5 cut the aromatic polyester resin extrudate while always in contact with the front end surface 1a of the nozzle die 1, the aromatic polyester resin extrudate is cut in the unfoamed portion immediately after being discharged from the nozzle outlet 11 of the nozzle die 1 to produce particulate cut pieces. A cutting step can be carried out in which the extruded foam is cut to prepare primary foamed particles.

[0056] As described above, the rotary blade 5 rotates at a constant rotation speed, and the rotation speed of the rotary blade 5 is preferably 2000 rpm to 10000 rpm, more preferably 2000 rpm to 9000 rpm, and particularly preferably 2000 rpm to 8000 rpm. A rotation speed within the above range is advantageous in that cutting reliability is improved or that adhesion of the particulate cut material to each other can be suppressed.

[0057] The particulate cut pieces obtained as described above are scattered toward the cooling drum 41 simultaneously with being cut by the cutting stress of the rotary blade 5, and immediately collide with the cooling water 42 that covers the inner peripheral surface of the peripheral wall portion 41b of the cooling drum 41. The particulate cut pieces continue to foam even before colliding with the cooling water 42, and grow into approximately spherical shapes due to foaming. Therefore, the obtained primary foamed aromatic polyester resin particles are approximately spherical.

[0058] As described above, after the aromatic polyester resin extrudate is cut by the rotary blade 5, the particulate cut pieces are immediately cooled with the cooling water 42, thereby preventing excessive foaming of the aromatic polyester resin primary foam particles. As described above, the cooling water 42 flowing along the inner circumferential surface of the peripheral wall portion 41b of the cooling drum 41 flows in a spiral. Therefore, it is preferable to collide the particulate cut pieces P with the cooling water 42 obliquely and from the upstream side to the downstream side of the flow of the cooling water 42, thereby causing them to enter the cooling water 42. In FIG. 3, the flow direction of the cooling water is indicated by "F."

[0059] When the obtained primary foamed particles are heated as described above to cause secondary expansion, a certain proportion of the secondary foamed particles adhere to each other, forming bonded particles. To prevent this, an anti-bonding agent spreading step can be carried out, in which an anti-bonding agent is spread on the surface of the primary foamed particles. Spreading can be achieved, for example, by dry-blending the primary foamed particles with the anti-bonding agent. The anti-bonding agent can be zinc stearate, magnesium stearate, stearic acid amide (e.g., 1,2-hydroxystearic acid amide), etc., but zinc stearate is preferred in terms of the fusion properties of molded articles. In the step of spreading the anti-bonding agent on the primary bonded particles to prepare primary bonded particles having the anti-bonding agent spread on their surfaces, the amount of the anti-bonding agent used can be 0.015 to 0.025 parts by mass, preferably 0.018 to 0.022 parts by mass, per 100 parts by mass of the primary bonded particles. Using an amount of the anti-bonding agent within the above range is advantageous in terms of preventing adhesion between secondary bonded particles and the fusion properties of molded articles.

[0060] A step of heating the primary particles having the antibinding agent spread on the surface with steam to cause secondary expansion to prepare secondary expanded particles may be carried out. In this step, water vapor is preferred as the steam from the viewpoint of simplicity. The temperature of the steam may be 60 to 100°C, preferably 65 to 95°C. Secondary expansion can be carried out, for example, by introducing the primary expanded particles into a pre-expander filled with water vapor and stirring them.

[0061] (Method of manufacturing an aromatic polyester resin foam molded product) The aromatic polyester resin foam molded article of the present invention can be typically produced by subjecting the aromatic polyester resin of the present invention to in-mold foam molding. Therefore, the matters described in the sections on the aromatic polyester resin foam beads of the present invention and their production method can be applied to the aromatic polyester resin foam molded article of the present invention and their production method. For example, various matters such as the type, content, physical properties, etc. of the aromatic polyester resin, crosslinking agent, blowing agent, etc. described in the sections on the aromatic polyester resin foam beads and their production method can be applied to the aromatic polyester resin foam molded article and its production method.

[0062] The aromatic polyester resin foam molded article of the present invention can be produced, for example, by filling the expanded aromatic polyester resin beads of the present invention into the cavity of a molding die (preferably a molding metal mold), heating the expanded beads, and then thermally fusing the expanded beads together under their expansion pressure. The heating medium for the expanded aromatic polyester resin beads filled into the mold is not particularly limited, and examples include steam, hot air, and warm water, with steam being preferred. The heating temperature and time can be appropriately selected taking into account the size and amount of the expanded beads used, the type of resin constituting the expanded beads, and the density and shape of the foam molded article, etc.

[0063] (Aromatic polyester resin foam molding) The aromatic polyester resin foam molded article of the present invention is a foam molded article composed of a heat-fused body of the aromatic polyester resin foam beads of the present invention, and more specifically, is a foam molded article in which a plurality of aromatic polyester resin foam beads are heat-fused together to form an integrated body.

[0064] The aromatic polyester resin foam molded article may contain the aromatic polyester resin in an amount of 80% by mass or more, 90% by mass or more, 95% by mass or more, 98% by mass or more, 99% by mass or more, 80 to 99.5% by mass, 80 to 99% by mass, 80 to 98% by mass, 80 to 95% by mass, 80 to 90% by mass, 90 to 99.5% by mass, 90 to 99% by mass, 90 to 98% by mass, 90 to 95% by mass, etc. The aromatic polyester resin may contain polyethylene terephthalate in an amount of 80% by mass or more, 90% by mass or more, 95% by mass or more, 98% by mass or more, 99% by mass or more.

[0065] The aromatic polyester resin foam molded product contains zinc element. The amount of zinc element contained in the aromatic polyester resin foam molded product can be 0.0010 mass% or more and 0.0022 mass% or less, preferably 0.0010 mass% or more and 0.0021 mass% or less, and more preferably 0.0010 mass% or more and 0.0020 mass% or less, relative to the mass of the foam molded product.

[0066] The density of the aromatic polyester resin foam molding is set to 0.05 g / cm3 from the viewpoint of lightness and mechanical strength. 3 More than 0.7g / cm 3 Preferably less than 0.06 g / cm 3 More than 0.6g / cm 3 Less than 0.06 g / cm is more preferable. 3 More than 0.3g / cm 3 The following is particularly preferred. The density of the foamed molded article is determined by measuring the mass (a) and volume (b) of a rectangular parallelepiped test piece (e.g., 75 mm x 300 mm x 30 mm) cut from the foamed molded article after molding and drying at 55°C for 20 hours or more, each to three or more significant figures, and then using the formula (a) / (b). Specifically, it is determined by the method described in the Examples.

[0067] Aromatic polyester resin foam molded articles have a high compressive modulus. The compressive modulus may be 100 kJ or more, 120 kJ or more, etc. per 1 kg of foam molded article, preferably 120 to 200 kJ, and more preferably 130 to 200 kJ. The compressive modulus is determined according to a method in accordance with JIS K7220:2006. Specifically, it is determined by the method described in the examples.

[0068] The aromatic polyester resin foamed molded article has a high degree of fusion between the foamed particles, which is evaluated by the method described in the examples. [Example]

[0069] Hereinafter, one embodiment of the present invention will be described in more detail with reference to examples, but the present invention is not limited to these. The methods for determining various physical properties in the examples are as follows.

[0070] (Average particle size of expanded particles) The average particle size of the expanded aromatic polyester resin particles was measured by sieving 50 g of the expanded particles through a number of sieves (sieves with different mesh sizes as specified in JIS: 6.70 mm, 5.60 mm, 4.75 mm, 4.00 mm, 3.35 mm, 2.80 mm, 2.36 mm, 2.00 mm, 1.70 mm, 1.40 mm, 1.18 mm, 1.00 mm, 0.850 mm, 0.710 mm, 0.600 mm, 0.500 mm) in order from the largest mesh size to the smallest mesh size. Depending on the particle size of each particle, the expanded particles were unable to pass through the sieves with the specified mesh size and remained on each sieve. The average particle size of the expanded particles remaining on each sieve was determined based on the size of the sieve openings, as shown in the following table. For example, the particle size of the expanded particles remaining on a sieve with an opening size of 1.70 mm was determined to be 1.85 mm.

[0071] [Table 2]

[0072] (Bulk density of expanded particles) The bulk density of the expanded beads was measured in accordance with JIS K6911:1995 "General testing methods for thermosetting plastics." That is, it was measured using an apparent density measuring device in accordance with JIS K6911, and calculated using the following formula. Bulk density (g / L) = [mass of measuring cylinder containing sample (g) - mass of measuring cylinder (g)] / [volume of measuring cylinder (L)]

[0073] (combined particles) The secondary expanded particles bonded together were evaluated as follows: All of the expanded particles were passed through a wire mesh with a mesh spacing of 1 cm. The mass (g) of the secondary expanded particles remaining on the wire mesh was measured, and the amount of blocking (%) was calculated using the following formula: Blocking amount (%) = (mass of expanded particles remaining on the wire mesh (g) / total mass of expanded particles (g)) x 100 The blocking amount was classified as follows: ◯: Blocking amount is 3.0% or less ×: Blocking amount is greater than 3.0%

[0074] (Zinc element content in foamed beads and foamed molded products) The zinc content was measured as follows. The sample was the expanded beads themselves for the expanded beads, and the expanded molded product from which the skin layer had been removed for the expanded molded product. A precisely weighed 0.5 g sample was heated at 450°C for 5 hours and incinerated. (ashing conditions) Heating device: Yamato Scientific Co., Ltd. "Muffle furnace FP-410" Ashing conditions: 450°C x 5 hours (sample weight: 0.5 g) The resulting ash was mixed with 2 mL of concentrated hydrochloric acid (Kanto Chemical's Ultrapur-100 ultra-high purity reagent). The insoluble matter in the mixture was filtered through ADAVANTEC No. 7 filter paper, and the filtrate was diluted to 50 mL with purified water to prepare a test solution. The zinc concentration of the test solution was measured under the following ICP measurement conditions. The zinc concentration was determined from a calibration curve. (ICP measurement conditions) Measurement equipment: Shimadzu Corporation's "ICPE-9000" multi-type ICP optical emission spectrometer ICPE-9000 Measured element = Zn (202.548nm) Observation direction = Axial direction High frequency output = 1.20 kW Carrier flow rate = 0.7 L / min Plasma flow rate = 10.0 L / min Auxiliary flow rate=0.6L / min Exposure time = 30 seconds Calibration standard solution = SPEX "XSTC-13" general-purpose mixed standard solution, 31 elements mixed (base 5% HNO3), approximately 10 mg / L each The zinc element content in the sample was calculated using the following formula. Zinc element content (wt%) = zinc element concentration (μg / mL) × 50 (mL) ÷ sample mass (0.5 g) ÷ 10000

[0075] (Density of foamed molded product) The mass (a) and volume (b) of a rectangular parallelepiped test piece (e.g., 75 mm x 300 mm x 30 mm) cut out from a foam molded product (dried at 55°C for 20 hours or more after molding) were measured to have three or more significant figures, and the density (g / L) of the foam molded product was calculated using the formula (a) / (b).

[0076] (Compression test: Evaluation of compressive modulus and compressive properties) The compressive modulus was measured in accordance with JIS K7220:2006. Specifically, the compressive modulus was measured using a Shimadzu Corporation "Autograph AG-X plus 100kN" universal testing machine and a Shimadzu Corporation "TRAPEZIUMX" universal testing machine data processing system. The test specimen size was 50mm x 50mm x 25mm thick (excluding the skin layer), and three specimens were used. The test specimens were conditioned for 16 hours in a standard atmosphere (JIS K 7100:1999, "23 / 50" grade 2) before use. The measurements were performed under the same conditions, with a compression rate of 2.5mm / min. The load region with the maximum slope was determined from the resulting graph, and the compressive modulus (MPa) was calculated using the universal testing machine data processing system. Furthermore, the obtained compressive elastic modulus (MPa) and the density of the test specimen (g / cm 3 ) and the ratio of compressive elastic modulus to the compact density (KJ / kg) was calculated. Using the obtained ratio (KJ / kg), the compression properties of the foamed molded article were evaluated based on the following indexes. 〇: The ratio obtained is 130 or more △: The obtained ratio is 120 or more and less than 130 ×: The obtained ratio is less than 120

[0077] (Evaluation of fusion properties of foam molded products) In the evaluation of fusion bonding, the foam molded article was broken along the thickness direction immediately after molding (immediately after being removed from the mold), and the fusion bonding was evaluated by evaluating the fracture surface according to the following criteria. ○: When the fracture surface is rubbed with a finger, the foam particles hardly come off. △: When the fracture surface is rubbed with a finger, some of the foam particles come off. ×: When the fracture surface is rubbed with a finger, most of the foam particles come off.

[0078] (comprehensive evaluation) Based on the evaluation results of the bonded particles, the evaluation results of the fusion properties of the foamed molded article, and the evaluation results of the compression properties of the foamed molded article, the evaluation was made according to the following criteria. O: All evaluation results are "O". △: One or more evaluation results are "△" and not all evaluation results are "×". ×: One or more evaluation results are "×".

[0079] Example 1 (Production of primary foam particles) Plant-derived polyethylene terephthalate (intrinsic viscosity: 0.08 dL / g, density: 1400 kg / m 3 100 parts by weight of polyethylene terephthalate containing talc (polyethylene terephthalate content: 60 wt%, talc content: 40%, intrinsic viscosity of polyethylene terephthalate: 0.82 dL / g), 1.8 parts by weight of a masterbatch (polyethylene terephthalate content: 60 wt%, talc content: 40%, intrinsic viscosity of polyethylene terephthalate: 0.82 dL / g) containing polyethylene terephthalate, 0.22 parts by weight of pyromellitic anhydride, and butane (containing 35 wt% isobutane and 65 wt% normal butane) as a blowing agent in an amount of 1.15 parts by weight per 100 parts by weight of polyethylene terephthalate, in the same manner as in Example 1 of JP 2015-98587 A, to obtain expanded particles (primary expanded particles). The bulk density of the primary expanded particles was 0.15 g / cm. 3 It was.

[0080] (Production of secondary foam particles) 100 parts by mass of the obtained primary expanded particles were dry-blended with zinc stearate (Dainichi Chemical Industry Co., Ltd., Daiwax ZF) to obtain primary expanded particles with 0.02 parts by mass of zinc stearate attached to the surface. Next, 6000 g of the primary expanded particles with zinc stearate attached to the surface were placed in a normal pressure pre-expander preheated to 88°C with steam, and heated at 88°C for 45 seconds while stirring to obtain secondary expanded particles. The bulk density of the secondary expanded particles was 0.069 g / cm. 3 It was.

[0081] (Production of foam molded products) The resulting secondary foamed particles were left at 23°C and atmospheric pressure for 14 days immediately after production, then filled into a 30 mm x 300 mm x 400 mm molding die and heated with steam at 0.05 MPa for 60 seconds and with steam at 0.10 MPa for 100 seconds, and then the maximum surface pressure of the foamed molded product was reduced to 0.01 MPa to obtain a foamed molded product.

[0082] Example 2 Primary expanded beads, secondary expanded beads, and expanded molded articles were obtained in the same manner as in Example 1, except that the heating time in the atmospheric pre-expanding machine was changed to 50 seconds. The bulk density of the secondary expanded beads was 0.067 g / cm. 3 It was.

[0083] Example 3 Primary foamed particles, secondary foamed particles, and foamed molded articles were obtained in the same manner as in Example 1, except that the amount of primary foamed particles charged into the atmospheric pre-expanding machine was changed to 15,000 g and the heating time in the atmospheric pre-expanding machine was changed to 50 seconds. The bulk density of the secondary foamed particles was 0.098 g / cm. 3 It was.

[0084] Example 4 Primary foamed particles, secondary foamed particles, and foamed molded articles were obtained in the same manner as in Example 1, except that the amount of primary foamed particles charged into the atmospheric pre-expanding machine was changed to 15,000 g and the heating time in the atmospheric pre-expanding machine was changed to 65 seconds. The bulk density of the secondary foamed particles was 0.091 g / cm. 3 It was.

[0085] (Comparative Example 1) Except for not using zinc stearate, primary expanded particles and secondary expanded particles were obtained in the same manner as in Example 1. Since the secondary expanded particles bonded together in the atmospheric pre-expansion machine to form bonded particles, secondary expanded particles that could not be used for foaming could not be obtained.

[0086] (Comparative Example 2) Primary expanded particles were obtained in the same manner as in Example 1. The bulk density of the primary expanded particles was 0.15 g / cm 3 The average particle size was 2.53 mm. Low-density expanded particles could not be obtained by primary expansion alone.

[0087] (Reference example 1) Primary foamed particles, secondary foamed particles, and foamed molded articles were obtained in the same manner as in Example 1, except that the amount of zinc stearate used was changed to 0.03 parts by mass, 1500 g of primary foamed particles with zinc stearate attached to their surfaces were placed in an atmospheric pre-expander preheated to 68°C with steam, and heated at 68°C for 15 seconds while stirring. The bulk density of the secondary foamed particles was 0.099 g / cm. 3 It was.

[0088] (Reference example 2) Primary foamed particles, secondary foamed particles, and foamed molded articles were obtained in the same manner as in Example 1, except that the amount of zinc stearate used was changed to 0.03 parts by mass, and 1500 g of primary foamed particles with zinc stearate attached to the surface were placed in an atmospheric pre-expander preheated to 75°C with steam, and heated for 60 seconds with stirring. The bulk density of the secondary foamed particles was 0.080 g / cm. 3 It was.

[0089] (Reference example 3) Primary expanded beads, secondary expanded beads, and expanded molded articles were obtained in the same manner as in Example 1, except that the amount of zinc stearate used was changed to 0.05 parts by mass and the heating time in the atmospheric pre-expanding machine was changed to 80 seconds. The bulk density of the secondary expanded beads was 0.080 g / cm. 3 It was.

[0090] (Reference example 4) Primary expanded beads, secondary expanded beads, and expanded molded articles were obtained in the same manner as in Example 1, except that the amount of zinc stearate used was changed to 0.05 parts by mass and the heating time in the atmospheric pre-expander was changed to 64 seconds. The bulk density of the secondary expanded beads was 0.070 g / cm. 3 It was.

[0091] (Reference example 5) Primary expanded beads, secondary expanded beads, and expanded molded articles were obtained in the same manner as in Example 1, except that the amount of zinc stearate used was changed to 0.05 parts by mass and the heating time in the atmospheric pre-expanding machine was changed to 52 seconds. The bulk density of the secondary expanded beads was 0.096 g / cm. 3 It was.

[0092] (Reference example 6) Primary foamed particles, secondary foamed particles, and foamed molded articles were obtained in the same manner as in Example 1, except that the amount of zinc stearate used was changed to 0.05 parts by mass, 6000 g of primary foamed particles with zinc stearate attached to their surfaces were charged into an atmospheric pre-expander preheated to 89°C with steam, and heated at 89°C for 55 seconds while stirring. The bulk density of the secondary foamed particles was 0.073 g / cm. 3 It was.

[0093] (Reference example 7) Primary foamed particles, secondary foamed particles, and foamed molded articles were obtained in the same manner as in Example 1, except that the amount of zinc stearate used was changed to 0.05 parts by mass, 6000 g of primary foamed particles with zinc stearate attached to their surfaces were placed in an atmospheric pre-expander preheated to 85°C with steam, and heated at 85°C for 38 seconds while stirring. The bulk density of the secondary foamed particles was 0.101 g / cm. 3 It was.

[0094] (Reference example 8) Primary foamed particles, secondary foamed particles, and foamed molded articles were obtained in the same manner as in Example 1, except that zinc stearate was replaced with magnesium stearate (manufactured by NOF Corporation, magnesium stearate), and 2000 g of primary foamed particles with magnesium stearate attached to the surface were placed in an atmospheric pre-expander preheated to 74°C with steam, and heated at 74°C for 60 seconds while stirring. The bulk density of the secondary foamed particles was 0.085 g / cm. 3 It was.

[0095] (Reference example 9) Primary foamed particles, secondary foamed particles, and foamed molded articles were obtained in the same manner as in Example 1, except that the amount of zinc stearate and its content was changed to 0.03 parts by mass of magnesium stearate (manufactured by NOF Corporation, Co., Ltd., Magnesium Stearate), and that 1,500 g of primary foamed particles with magnesium stearate attached to their surfaces were placed in an atmospheric pre-expander preheated to 67°C with steam, and heated at 67°C for 15 seconds while stirring. The bulk density of the secondary foamed particles was 0.095 g / cm. 3 It was.

[0096] (Reference example 10) Primary foamed particles, secondary foamed particles, and foamed molded articles were obtained in the same manner as in Example 1, except that the amount of zinc stearate and its content was changed to 0.03 parts by mass of magnesium stearate (manufactured by NOF Corporation, Co., Ltd., Magnesium Stearate), and that 1500 g of primary foamed particles with magnesium stearate attached to their surfaces were placed in an atmospheric pre-expander preheated to 75°C with steam and heated at 75°C for 60 seconds while stirring. The bulk density of the secondary foamed particles was 0.082 g / cm. 3 It was.

[0097] (Reference example 11) Primary foamed particles, secondary foamed particles, and foamed molded articles were obtained in the same manner as in Example 1, except that zinc stearate was replaced with 1,2-hydroxystearic acid amide (Diamid KH, manufactured by Mitsubishi Chemical Corporation), and 2000 g of primary foamed particles with the amide attached to their surfaces were placed in an atmospheric pre-expander preheated to 75°C with steam, and heated at 75°C for 60 seconds while stirring. The bulk density of the secondary foamed particles was 0.075 g / cm. 3 It was.

[0098] (Reference example 12) Primary foamed particles, secondary foamed particles, and foamed molded articles were obtained in the same manner as in Example 1, except that the zinc stearate and its amount were changed to 1,2-hydroxystearic acid amide (Diamid KH, manufactured by Mitsubishi Chemical Corporation) and 0.03 parts by mass, respectively, and 1500 g of primary foamed particles with the amide attached to their surfaces were placed in an atmospheric pre-expander preheated to 67°C with steam, and heated at 67°C for 15 seconds while stirring. The bulk density of the secondary foamed particles was 0.100 g / cm. 3 It was.

[0099] (Reference example 13) Primary foamed particles, secondary foamed particles, and foamed molded articles were obtained in the same manner as in Example 1, except that the zinc stearate and its amount were changed to 1,2-hydroxystearic acid amide (Diamid KH, manufactured by Mitsubishi Chemical Corporation) and 0.03 parts by mass, respectively, and 1500 g of primary foamed particles with the amide attached to their surfaces were placed in an atmospheric pre-expander preheated to 75°C with steam, and heated at 75°C for 60 seconds while stirring. The bulk density of the secondary foamed particles was 0.077 g / cm. 3 It was.

[0100] Tables 3 to 5 show the physical properties measured for the expanded beads and foamed molded articles obtained in the examples and comparative examples.

[0101] [Table 3]

[0102] [Table 4]

[0103] [Table 5] [Explanation of symbols]

[0104] 1 Nozzle mold 2 rotation axes 3 Driving member 4 Cooling material 41 Cooling drum 42 Cooling water 5 Rotary blade P Aromatic polyester resin foam particles

Claims

1. Expanded aromatic polyester resin particles containing zinc element, Expanded beads, the zinc content of which is 0.0015% by mass or more and 0.0025% by mass or less of the expanded beads.

2. The average particle size is 2.60 mm or more and 3.50 mm or less, and the bulk density is 0.03 g / cm ３ 0.120g / cm or more ３ 2. The expanded particles of claim 1, wherein:

3. The expanded aromatic polyester resin beads according to claim 1 or 2, wherein the expanded aromatic polyester resin beads contain polyethylene terephthalate in an amount of 80% by mass or more.

4. A zinc-containing aromatic polyester resin foam molded article, The zinc element content of the foamed molded article is 0.0010 mass% or more and 0.0022 mass% or less, and the density is 0.03 g / cm ３ 0.140g / cm or more ３ A foam molded article as follows:

5. The foam molded article according to claim 4, wherein the aromatic polyester resin foam molded article contains polyethylene terephthalate in an amount of 80% by mass or more.

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