Aromatic polyester resin foamed particles and foamed molding

Abstract

To provide aromatic polyester resin foamed particles that are suitable for the production of a thin foamed molding, and a foamed molding obtained by thermal fusion and integration of the foamed particles.SOLUTION: Aromatic polyester resin foamed particles having an average particle diameter of 2.3 mm or less and a Feret diameter ratio (L / T) of 1.05 to 1.25, wherein the Feret diameter ratio (L / T) is a ratio of a length (L) of a long axis of the Feret diameter to a length (T) of a short axis of the Feret diameter.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] Foam molded articles are widely used due to advantages such as light weight and excellent heat insulation. Foam bead molding is a method of producing a foam molded article that conforms to the shape of the mold by filling a molding die with foam beads, heating the foam beads, and fusing the foam beads together (Patent Document 1). However, when foam bead molding is performed in a mold with a complex shape, it is not easy to fill the foam beads into the fine details of the mold. As a result, it is not easy to produce a foam molded article with thin-walled portions, and even if it is produced, the yield is low. In order to produce a foam molded article with higher mold shape precision, a method (cracking method) is sometimes used in which, when filling the mold with foam beads, a volume of foam beads slightly larger than the volume of the mold is filled and then foam molded. [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] However, the inventors have recognized that even with the cracking method, it is not easy to fill the foamed beads into the fine details of the mold, and that the filling pressure applied to the foamed beads in the mold is not constant, making it difficult to accurately produce thin-walled portions of a foamed molded article. Therefore, an object of the present invention is to provide expanded aromatic polyester resin beads suitable for producing thin foamed molded articles, and foamed molded articles in which the expanded beads are heat-fused and integrated. [Means for solving the problem]

[0005] As a result of intensive research to solve the above problems, the present inventors have found that expanded aromatic polyester resin beads having an average particle diameter of 2.3 mm or less and a Feret diameter ratio (L / T) of 1.05 to 1.25 can be used to produce expanded molded articles with high precision even in expansion molding using a 5 mm thick mold, and that the expanded molded articles have excellent bending properties, thereby completing the present invention.

[0006] The present invention typically includes the following aspects. Section 1. Expanded aromatic polyester resin particles having an average particle diameter of 2.3 mm or less and a Feret diameter ratio (L / T) of 1.05 to 1.25, where the Feret diameter ratio (L / T) is the ratio of the long side length (L) to the short side length (T) of the Feret diameter. Section 2. Item 1. Expanded aromatic polyester resin beads for in-mold foam molding according to Item 1, which are polyethylene terephthalate-containing expanded aromatic polyester resin beads, the polyethylene terephthalate content of which is 90% by mass or more. Section 3. Item 3. Expanded aromatic polyester resin particles for in-mold foam molding according to Item 1 or 2, having a crystallinity of less than 15%. Section 4. Item 4. Expanded aromatic polyester resin particles for in-mold expansion molding according to any one of Items 1 to 3, having a bulk density of 50 g / L to 700 g / L. Section 5. Item 5. A foamed molded article of the expanded aromatic polyester resin beads according to any one of items 1 to 4. Section 6. Item 6. The foamed molded article according to Item 5, having a density of 50 g / L to 700 g / L. [Effects of the Invention]

[0007] According to the present invention, a foamed molded article having a thin wall shape and excellent dimensional accuracy and bending properties can be provided. According to the present invention, it is possible to provide expanded beads that can be used in in-mold foam molding to realize the foamed molded article. These effects are made possible not only by reducing the particle size of the expanded aromatic polyester resin beads but also by setting the Feret diameter ratio within a specific range. [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] 1 is a schematic diagram showing a nozzle die 1 used in Example 3 etc., as seen from the front. In this nozzle die, an outlet portion 11 is arranged on an imaginary circle A at the front end surface 1a. [Figure 3] 1 is a schematic diagram showing a state in which expanded aromatic polyester resin particles enter cooling water. FIG. [Figure 4] 1 is a schematic diagram showing a nozzle die 1' used in Example 1 etc., as seen from the front. In this nozzle die, outlets 11 are arranged on imaginary circles A and B on the front end surface 1a. 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, 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."

[0012] (Aromatic polyester resin foam particles) In the present invention, the expanded aromatic polyester resin particles contain an aromatic polyester resin as a main component, where "main component" means that the content of the aromatic polyester resin in the expanded aromatic polyester resin particles is 80% by mass or more, preferably 90% by mass or more.

[0013] (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.

[0014] 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.

[0015] 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.

[0016] 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.

[0017] 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.

[0018] 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.

[0019] 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.

[0020] 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 %.

[0021] 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.

[0022] 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.

[0023] 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.

[0024] 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.

[0025] 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.

[0026] 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.

[0027] 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.

[0028] 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.

[0029] 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.

[0030] The expanded aromatic polyester resin particles may have an average particle size of 2.3 mm or less. The average particle size is preferably 1.0 to 2.3 mm, more preferably 1.2 to 2.2 mm, and even more preferably 1.5 to 2.2 mm. When the average particle size is within this range, the expanded particles are more easily packed into the fine details of the mold, thereby providing a foamed molded article with excellent dimensional accuracy and bending properties in a thin-walled shape.

[0031] The average particle size of the expanded aromatic polyester resin particles was determined by sieving 50 g of the expanded particles through a number of sieves with different mesh sizes specified by 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 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 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.

[0032] [Table 1]

[0033] The Feret diameter ratio (L / T) of the expanded aromatic polyester resin particles may be 1.05 to 1.25. The Feret diameter ratio is preferably 1.10 to 1.24 mm, more preferably 1.15 to 1.24 mm. When the Feret diameter ratio is within the above range, in-mold expansion of the expanded beads can provide a foamed molded article with excellent dimensional accuracy of thin-walled shapes and excellent bending properties. The Feret diameter ratio is the ratio (L / T) of the long side length (L) to the short side length (T) of a rectangle circumscribing a figure (i.e., the figure formed when the expanded beads are projected onto a plane) obtained by capturing an image generated by parallel transmitted illumination from a direction perpendicular to the observation surface in measurement using a dynamic image analysis particle shape / particle size distribution analyzer or a digital microscope. This ratio is specifically determined by the method described in the Examples.

[0034] The bulk density of the expanded aromatic polyester resin beads can be 50 g / L or more and 700 g / L or less. From the viewpoint of improving the expansion power and the fusion strength of the secondary expanded beads, the bulk density is preferably 55 g / L or more and 600 g / L or less, more preferably 60 g / L or more and 500 g / L or less, and particularly preferably 65 g / L or more and 400 g / L or less. The bulk density of the expanded aromatic polyester resin beads can be adjusted by the extrusion pressure of the raw resin at the nozzle outlet of the nozzle mold or the amount of blowing agent. The extrusion pressure of the raw 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 can be measured in accordance with JIS K6911:1995, "General Testing Methods for Thermosetting Plastics." More detailed information is provided in the Examples.

[0035] The crystallinity of the expanded aromatic polyester resin beads is preferably 15% or less, more preferably 10% or less, even more preferably 6% or less, and particularly preferably 5.5% or less, because this improves the fusion properties of the expanded beads during expansion molding. The crystallinity is determined by the method described in JIS K7122:1987 and JIS K7122:2012, and more specifically, 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 method including, for example, a step of feeding an aromatic polyester resin, and optionally a crosslinking agent, to an extruder and melt-kneading them in the presence of a blowing agent to prepare a melt-kneaded mixture; a step of extruding and foaming the melt-kneaded mixture, preferably under gaseous conditions, to prepare an extruded foam; and a cutting step of cutting the extruded foam to prepare expanded 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. In this production method, setting the nozzle die outlet diameter, the extrusion rate of the melt-kneaded mixture, and the cutter rotation speed in the cutting step to the specific ranges described below is advantageous for producing expanded beads having an average particle size of 2.3 mm or less and a Feret diameter ratio of 1.05 to 1.25.

[0037] The aromatic polyester resin can be crosslinked by a known method. For example, the aromatic polyester resin and a crosslinking agent are fed into 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, by feeding an aromatic polyester resin material to an extruder and melt-kneading it in the presence of a foaming agent, and then extruding the aromatic polyester resin extrudate from a nozzle die attached to the front end of the extruder and foaming it while cutting it with a rotary blade to produce expanded aromatic polyester resin particles.

[0041] The extruder is not particularly limited as long as it is a conventionally widely 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 together.

[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 10 to 150, more preferably 15 to 140, even more preferably 20 to 140, and particularly preferably 20 to 130. From the viewpoint of controlling the average particle size and Feret diameter ratio, the diameter of the outlet portion 11 of the nozzle in the nozzle mold 1 is preferably 0.2 to 1.5 mm, more preferably 0.3 to 1.3 mm, and particularly preferably 0.4 to 1.1 mm. The length of the land portion of the nozzle mold 1 is preferably 0.5 to 20 times the diameter of the outlet portion 11 of the nozzle in the nozzle mold 1, and more preferably 1 to 15 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 two 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] The extrusion rate of the aromatic polyester resin extrudate is preferably 10 to 70 kg / h, more preferably 15 to 60 kg / h, and particularly preferably 20 to 50 kg / h, from the viewpoint of controlling the average particle size and Feret diameter ratio.

[0048] 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.

[0049] 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.

[0050] 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.

[0051] 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.

[0052] 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.

[0053] 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.

[0054] 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.

[0055] 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.

[0056] Since all of the rotary blades 5 are constantly in contact with the front end face 1a of the nozzle die 1 while cutting the aromatic polyester resin extrudate, 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, producing particulate cut material.

[0057] As described above, the rotary blade 5 rotates at a constant rotation speed, and from the viewpoint of controlling the average particle size and Feret diameter ratio, the rotation speed of the rotary blade 5 is preferably 2000 rpm or more and 10000 rpm or less, more preferably 2000 rpm or more and 9000 rpm or less, even more preferably 2000 rpm or more and 8000 rpm or less, and particularly preferably 2000 rpm or more and 4000 rpm or less. A rotation speed within the above range is advantageous in that the reliability of cutting is improved or that adhesion of the particulate cut products to each other can be suppressed.

[0058] The particulate cut material obtained as described above is scattered toward the cooling drum 41 simultaneously with cutting due to the cutting stress of the rotary blade 5, and immediately collides 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 material continues to foam even before colliding with the cooling water 42, and grows into a substantially spherical shape due to foaming. Therefore, the obtained expanded aromatic polyester resin particles are substantially spherical. When the expanded aromatic polyester resin particles are filled into a mold to perform in-mold foaming, the expanded aromatic polyester resin particles have excellent mold filling properties, allowing the aromatic polyester resin particles to be filled uniformly into the mold, resulting in a homogeneous in-mold foamed article.

[0059] 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 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."

[0060] In the above, as an example of a method for producing expanded aromatic polyester resin beads, a case where the production apparatus shown in FIGS. 1 to 3 is used has been described. However, the method for producing expanded aromatic polyester resin beads is not limited to this example, and examples thereof include: (1) a method in which an aromatic polyester resin is supplied to an extruder, melt-kneaded in the presence of a blowing agent, and extruded and foamed from a nozzle die attached to the front end of the extruder to produce strand-shaped aromatic polyester resin extrudates, and then cooled and cut into particles using a pelletizer or the like to produce expanded aromatic polyester resin beads; and (2) a method in which an aromatic polyester resin is supplied to an extruder, melt-kneaded in the presence of a blowing agent, and extruded and foamed from a T-die attached to the front end of the extruder to produce strand-shaped aromatic polyester resin extrudates, and then cooled and cut into particles using a pelletizer or the like to produce expanded aromatic polyester resin beads. (3) a method in which an aromatic polyester resin foam sheet is produced from an extruder, the aromatic polyester resin foam sheet is cooled, and then the aromatic polyester resin foam sheet is cut into particles to produce expanded aromatic polyester resin particles, or (4) a method in which an aromatic polyester resin is fed into an extruder and melt-kneaded in the presence of a blowing agent, an annular aromatic polyester resin extrudate is produced from a circular die attached to the front end of the extruder, the annular aromatic polyester resin extrudate is continuously cut along the extrusion direction from its inner to outer periphery to develop the annular aromatic polyester resin extrudate, and then the aromatic polyester resin foam sheet is cut into particles to produce expanded aromatic polyester resin particles. These methods are known.

[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 known in-mold foam molding. For example, aromatic polyester resin foam beads are filled into the cavity of a molding die (preferably a molding metal mold) and heated to expand the foam beads. The secondary foamed beads obtained by expanding the foam beads are thermally fused together by their expansion pressure, thereby producing an in-mold foam molded article with excellent dimensional accuracy of thin-walled shape and excellent bending properties. The heating medium for the aromatic polyester resin foam beads filled in the mold is not particularly limited, and examples include steam, hot air, hot water, etc., with steam being preferred.

[0062] (Aromatic polyester resin foam molding) The aromatic polyester resin foam molded article is a foam molded article formed from a fused body of the aromatic polyester resin foam beads of the present invention, and more specifically, a foam molded article in which a plurality of aromatic polyester resin foam beads are thermally fused together to form an integrated body. The foam molded article can typically be produced by in-mold foam molding of the foam beads. Therefore, the details described in the sections on the aromatic polyester resin foam beads and their manufacturing method can also be applied to the aromatic polyester resin foam molded article and its manufacturing method. For example, the various details, such as the type, content, and physical properties of the aromatic polyester resin, crosslinking agent, blowing agent, aliphatic hydrocarbon having 3 to 6 carbon atoms, etc., described in the sections on the aromatic polyester resin foam beads and their manufacturing method can also be applied to the aromatic polyester resin foam molded article and its manufacturing method.

[0063] In the present invention, the aromatic polyester resin foam molded article contains an aromatic polyester resin as a main component, where "main component" means that the content of the aromatic polyester resin in the aromatic polyester resin foam molded article is 80% by mass or more, preferably 90% by mass or more.

[0064] The density of the aromatic polyester resin foam molded article can be from 50 g / L to 700 g / L. From the viewpoint of lightness and mechanical strength, it is preferably from 55 g / L to 600 g / L, more preferably from 60 g / L to 500 g / L, even more preferably from 65 g / L to 400 g / L, and particularly preferably from 100 g / L to 350 g / L. The density of the foam 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 foam 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), as described in detail in the Examples.

[0065] Aromatic polyester resin foam molded articles have excellent bending properties, such as a high flexural modulus and a high maximum bending stress. The flexural modulus per 1 g / L of foam molded article may be 0.210 to 0.470 MPa, preferably 0.215 to 0.460 MPa, more preferably 0.220 to 0.450 MPa, and particularly preferably 0.240 to 0.450 MPa. The maximum bending stress per 1 g / L of foam molded article may be 0.009 to 0.030 MPa, preferably 0.0095 to 0.025 MPa, more preferably 0.010 to 0.020 MPa, and particularly preferably 0.010 to 0.017 MPa.

[0066] Aromatic polyester resin foam molded articles have excellent dimensional accuracy and bending properties even when they are thin-walled. Therefore, foam molded articles can be made into thinner or more complex shapes than before. Therefore, there are fewer restrictions on the shape design of foam molded articles than before. [Example]

[0067] 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.

[0068] (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 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 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.

[0069] [Table 2]

[0070] (Bulk density of expanded particles) The bulk density 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 of expanded particles (g / L) = [mass of measuring cylinder containing sample (g) - mass of measuring cylinder (g)] / [volume of measuring cylinder (L)]

[0071] (crystallinity) The crystallinity was measured according to the methods described in JIS K7122:1987 and JIS K7122:2012. 5.5±0.5 mg of sample was packed tightly at the bottom of an aluminum measuring container, and then an aluminum lid was placed on top. Differential scanning calorimetry was then performed using a Hitachi High-Tech Science DSC7000X, AS-3 differential scanning calorimeter. The sample was heated under a nitrogen gas flow rate of 20 mL / min in the following steps to obtain a DSC curve. Alumina was used as the reference material. (Step 1) Hold at 30°C for 2 minutes. (Step 2) The temperature is increased from 30°C to 290°C at a rate of 10°C / min. From the obtained DSC curve, the analysis software attached to the differential scanning calorimeter was used to determine the area of ​​the melting peak, the heat of fusion C1 (J / g) calculated from the area of ​​the melting peak, and the area of ​​the crystallization peak, the heat of crystallization C2 (J / g) calculated from this area. The heat of crystallization was subtracted from the heat of fusion, and the difference was calculated. The degree of crystallinity was determined by dividing this difference by 140.1 J / g, which is the theoretical heat of fusion for perfectly crystalline polyethylene terephthalate. Specifically, the heat of fusion was calculated from the area enclosed by the line connecting the point where the DSC curve departs from the low-temperature baseline and the point where the DSC curve returns to the high-temperature baseline, and the heat of crystallization was calculated from the area enclosed by the line connecting the point where the DSC curve departs from the low-temperature baseline and the point where the DSC curve returns to the high-temperature baseline, and the area enclosed by the line connecting the point where the DSC curve departs from the low-temperature baseline and the point where the DSC curve returns to the high-temperature baseline. That is, the crystallinity was calculated using the following formula: Crystallinity (%)=((C1-C2) / 140.1)×100

[0072] (Ferret diameter ratio (L / T)) The Feret diameter ratio (L / T ratio) of the expanded particles was measured using a dynamic image analysis particle shape and particle size distribution measuring device (Partan 3D, manufactured by Microtrack Bell). Three-dimensional image analysis was performed on 10,000 to 15,000 expanded particles to be measured, and the maximum Feret diameter (FLength), which is the length at which the distance between two parallel lines sandwiching the particle image is the longest, and the thickness (FThickness), which is the length at which the distance between two parallel lines sandwiching the particle image is the shortest, were calculated from their shapes, and the Feret diameter ratio (L / T) of the expanded particles was calculated based on the following formula. The Feret diameter ratios were calculated for all expanded particles, and their average values ​​are shown in Table 3. L / T Ratio = [Maximum Ferret Diameter (FLength)] / [Thickness (FThickness)]

[0073] (Moldability of thin-walled (5 mm thick) foam molded body) An in-mold foam molding machine equipped with molds (male and female molds) was prepared. When the male and female molds were clamped together, a rectangular parallelepiped cavity with interior dimensions of 300 mm length, 400 mm width, and 5 mm height was formed between the male and female molds. After the mold was filled with foamed particles at a filling air pressure of 0.3 MPa with 1 mm of mold cracking, steam was introduced from the female mold for 30 seconds to a pressure of 0.05 MPa (gauge pressure) in the cavity (one-sided heating). Steam was then introduced from the male mold for 30 seconds to a pressure of 0.05 MPa (gauge pressure) in the cavity (reverse one-sided heating). Steam was then supplied from both the male and female molds for 50 seconds to a pressure of 0.10 MPa (gauge pressure) in the cavity (double-sided heating). This heated and secondary-expanded the foamed particles, causing them to thermally fuse together and become one. After that, the introduction of water vapor into the cavity was stopped and the state was maintained for 50 seconds (heat retention process), and finally, cooling liquid was supplied into the cavity to cool the foam molded body in the mold, and then the cavity was opened and the foam molded body was removed. The surface of the resulting foamed molded article was visually observed and the moldability was evaluated based on the following criteria. ◯: It was visually confirmed that the foamed particles were filled up to the center and corners, and that there was no hole penetrating the center of the molded product or any chipping at the corners. x: It was visually confirmed that the expanded particles were not filled up to the center and corners, and that the molded article had a hole penetrating the center and / or chipped corners.

[0074] (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).

[0075] (Bending test of foam molded body: maximum bending stress and bending modulus) The maximum bending stress (maximum bending strength) was measured in accordance with JIS K7221-1:2006. Specifically, the maximum bending stress was measured using a Shimadzu Corporation "Autograph AG-X plus 100kN" universal testing machine and Shimadzu Corporation "TRAPEZIUM X" universal testing machine data processing software. Rectangular specimens (25mm wide x 130mm long x 20mm thick) were cut from foam molded products (dried at 55°C for at least 20 hours after molding). Five specimens were used. The specimens were conditioned for 16 hours under the standard atmosphere of JIS K7100:1999, "23 / 50" (temperature 23°C, relative humidity 50%), Class 2, and then used for the above-mentioned measurements under the same standard atmosphere. The test speed was 10mm / min. The radius of the pressure wedge and the fulcrum tip was 5R, and the distance between the fulcrums was 100mm. The load region where the slope was maximum was determined from the graph obtained by the measurement, and the apparent flexural modulus was calculated using the universal testing machine data processing. The intersection of this elastic modulus line and the stroke was set as the origin of elongation, and the corresponding maximum bending stress was automatically calculated.

[0076] (Evaluation of bending properties of foam molded products) The bending properties of the foamed molded article were evaluated according to the following criteria. ○: The flexural modulus per 1 g / L is 0.250 MPa·L / g or more, and the maximum bending stress per 1 g / L is 0.011 MPa·L / g or more. ×: Either or both of the flexural modulus per 1 g / L is less than 0.250 MPa·L / g and the maximum bending stress per 1 g / L is less than 0.011 MPa·L / g.

[0077] Example 1 (Foam bead manufacturing process) (1) Preparation of foam particles Expanded beads were produced using the production apparatus shown in FIGS. 1, 3 and 4 according to the following procedure.

[0078] Plant-derived polyethylene terephthalate (intrinsic viscosity: 0.80, density: 1400 kg / m 3 , melting point: 247.2°C, glass transition temperature: 78.7°C, mass average molecular weight: 74,000, plant content: 30%) 95% by mass and polyethylene naphthalate (intrinsic viscosity: 0.50, density: 1330 kg / m 3 An aromatic polyester resin composition was obtained by blending 100 parts by mass of an aromatic polyester resin material containing 5% by mass of polyethylene terephthalate (polyethylene terephthalate content: 60% by mass, talc content: 40% by mass, intrinsic viscosity of polyethylene terephthalate: 0.82), 1.8 parts by mass of a masterbatch obtained by incorporating talc into polyethylene terephthalate (polyethylene terephthalate content: 60% by mass, talc content: 40% by mass, intrinsic viscosity of polyethylene terephthalate: 0.82), and 0.25 parts by mass of pyromellitic anhydride.

[0079] The obtained aromatic polyester resin composition was fed to a single-screw extruder having a bore diameter of 65 mm and an L / D ratio of 35, and melt-kneaded at 290° C. The kneading time was 15 minutes.

[0080] Next, butane (containing 35% by mass of isobutane and 65% by mass of normal butane) was introduced into the extruder as a foaming agent, and the foaming agent was injected into the molten aromatic polyester resin composition, thereby uniformly dispersing the foaming agent in the aromatic polyester resin composition. At this time, the amount of butane added was 1.3 parts by mass per 100 parts by mass of the aromatic polyester resin material.

[0081] The molten aromatic polyester resin composition was then cooled to 280°C at the front end of the extruder, and the aromatic polyester resin composition was extruded and foamed through the nozzles of a nozzle die 1' (Fig. 4) attached to the front end of the extruder. The extrusion rate of this aromatic polyester resin composition was 25 kg / hour.

[0082] The nozzle mold 1' had 136 nozzles (each outlet portion 11 had a diameter of 0.5 mm), and all of the nozzle outlet portions 11 were arranged at equal intervals on the larger of two imaginary circles on the surface of the front end face 1a of the nozzle mold 1': 73 nozzles, i.e., imaginary circle A (diameter 139.5 mm), and 63 nozzles, i.e., imaginary circle B (diameter 120.5 mm), both arranged at equal intervals.

[0083] Two rotary blades 5 were integrally provided on the outer peripheral surface of the rear end of the rotary shaft 2, with a phase difference of 180° in the circumferential direction of the rotary shaft 2. Each rotary blade 5 was configured to move on imaginary circles A and B while constantly in contact with the front end surface 1a of the nozzle die 1'. The rotary shaft 2 passed through the front part 41a of a cooling drum 41 constituting the cooling member 4, and was connected to a driving member 3 which was a motor.

[0084] The cooling member 4 includes a cooling drum 41. The cooling drum 41 has a front portion 41a that is circular at the front and a cylindrical peripheral wall portion 41b that extends rearward from the outer periphery of the front portion 41a and has an inner diameter of 320 mm. Cooling water 42 at 30°C was supplied into the cooling drum 41 through a supply pipe 41d and a supply port 41c of the cooling drum 41. The internal volume of the cooling drum 41 was 17,684 cm. 3 It was.

[0085] The cooling water 42 flows 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 rate 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 flows along the inner circumferential surface of the circumferential wall 41b, the cooling water 42 gradually spreads in a direction perpendicular to the direction of its movement. As a result, 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. In FIG. 3, the cooling water 42 flows in the direction indicated by arrow F.

[0086] The rotary blade 5 disposed on the front end surface 1a of the nozzle mold 1' was rotated at a rotation speed of 2000 rpm, and the extrudate (extruded foam) of the aromatic polyester resin extruded and foamed from the outlet portion 11 of each nozzle of the nozzle mold 1' was cut by the rotary blade 5 to produce approximately spherical particulate cut products.

[0087] The extrudate of the aromatic polyester resin consisted of an unfoamed portion immediately after being extruded from the nozzle of the nozzle die 1' and a foamed portion in the process of foaming that was continuous with the unfoamed portion. The extrudate of the aromatic polyester resin was cut at the open end of the nozzle outlet 11, and the cutting of the extrudate of the aromatic polyester resin took place in the unfoamed portion.

[0088] When producing expanded beads, first, the rotating shaft 2 was not attached to the nozzle die 1' and the cooling member 4 was retracted from the nozzle die 1'. In this state, an aromatic polyester resin extrudate was extruded and foamed from the extruder, and it was confirmed that the aromatic polyester resin extrudate consisted of an unfoamed portion immediately after being extruded from the nozzle of the nozzle die 1' and a foamed portion in the process of foaming that was continuous with the unfoamed portion. After this confirmation, the rotating shaft 2 was attached to the nozzle die 1' and the cooling member 4 was placed in a predetermined position. Then, the rotating shaft 2 was rotated, and the aromatic polyester resin extrudate was cut with the rotary blade 5 at the open end of the nozzle outlet 11 to produce granular cut pieces.

[0089] The resulting particulate cutting material was thrown outward or forward by the cutting stress of the rotary blade 5. The thrown particulate cutting material collided obliquely with the surface of cooling water 42 flowing along the inner surface of the cooling drum 41 of the cooling member 4, from the upstream side to the downstream side of the flow of cooling water 42, so as to follow the cooling water 42, and the particulate cutting material entered the cooling water 42 and was immediately cooled.

[0090] The particulate cut material was discharged together with cooling water 42 through the discharge port 41e of the cooling drum 41, and then separated from the cooling water 42 in a dehydrator. In this manner, expanded beads (expanded aromatic polyester resin beads) were produced.

[0091] (Foam molding process) An in-mold foam molding machine equipped with molds (male and female molds) was prepared. When the male and female molds were clamped together, a rectangular parallelepiped cavity with interior dimensions of 300 mm length x 400 mm width x 30 mm height was formed between the male and female molds. After filling the mold with foamed particles with a 1 mm mold crack, steam was introduced into the cavity from the female mold for 70 seconds to set the cavity pressure to 0.05 MPa (gauge pressure) (one-sided heating). Steam was then introduced from the male mold for 70 seconds to set the cavity pressure to 0.05 MPa (gauge pressure) (reverse one-sided heating). Steam was then supplied from both the male and female molds for 50 seconds to set the cavity pressure to 0.10 MPa (gauge pressure) (double-sided heating). This heated and secondary-expanded the foamed particles, causing them to thermally fuse together and become one. After that, the introduction of water vapor into the cavity was stopped and the state was maintained for 100 seconds (heat retention process), and finally, a cooling liquid was supplied into the cavity to cool the foam molded body in the mold, and then the cavity was opened and the foam molded body was removed.

[0092] (Examples 2 to 5 and Comparative Examples 1 to 4) As the nozzle mold, a nozzle mold 1 (FIG. 2) having only an imaginary circle A or a nozzle mold 1′ (FIG. 4) having imaginary circles A (diameter 139.5 mm) and B (diameter 120.5 mm) was used, and the number of nozzle outlets 11 arranged on the imaginary circle of the nozzle mold was set to the numbers shown in Table 3, and the extrusion rate, amount of butane added, and rotation speed during extrusion were set to the conditions shown in Table 3. Expansion beads and foamed molded articles were obtained in the same manner as in Example 1.

[0093] Table 3 shows the physical properties measured for the expanded beads and foamed molded articles obtained in the examples and comparative examples.

[0094] [Table 3]

[0095] The results of Comparative Examples 3 and 4 show that even if the average particle diameter of the expanded beads was 2.0 mm, when the Feret diameter ratio (L / T) was outside the range of 1.05 to 1.25, both thin-wall shape formability and bending properties could not be achieved. Furthermore, the expanded beads of Comparative Example 4 had a small average particle diameter and a Feret diameter ratio close to 1.00, i.e., were nearly spherical, but had insufficient bending properties. Therefore, it was important that not only the average particle diameter be small but also the Feret diameter ratio (L / T) be within the range of 1.05 to 1.25. [Explanation of symbols]

[0096] 1: nozzle mold, 1': nozzle mold (nozzles arranged around two circumferences), 1a: front end surface, 2: rotating shaft, 3: driving member, 4: cooling member, 5: rotating blade, 11: outlet portion, 41: cooling drum, 41a: front portion, 41b: peripheral wall portion, 41c: supply port, 41d: supply pipe, 41e: discharge port, 41f: discharge pipe, 42: cooling water, P: aromatic polyester resin foam particles

Claims

1. Expanded aromatic polyester resin particles having an average particle diameter of 2.3 mm or less and a Feret diameter ratio (L / T) of 1.05 to 1.25, wherein the Feret diameter ratio (L / T) is the ratio of the long side length (L) to the short side length (T) of the Feret diameter.

2. 2. The expanded aromatic polyester resin beads for in-mold foam molding according to claim 1, which are polyethylene terephthalate-containing expanded aromatic polyester resin beads, the content of said polyethylene terephthalate being 90% by mass or more.

3. 2. The expanded aromatic polyester resin particles for in-mold foam molding according to claim 1, which have a crystallinity of less than 15%.

4. 2. The expanded aromatic polyester resin particles for in-mold foam molding according to claim 1, which have a bulk density of 50 g / L to 700 g / L.

5. A foamed molded article of the expanded aromatic polyester resin beads according to any one of claims 1 to 4.

6. The foamed molded article according to claim 5, having a density of 50 g / L to 700 g / L.

Images