WO2010090046A1

WO2010090046A1 - Method for manufacturing foamable thermoplastic resin particles, method for manufacturing thermoplastic resin foam particles, and method for manufacturing thermoplastic resin foam molded article

Info

Publication number: WO2010090046A1
Application number: PCT/JP2010/000799
Authority: WO
Inventors: 浅野泰正; 山下昌利; 木下隆之; 地海良輔; 樽本裕之
Original assignee: 積水化成品工業株式会社
Priority date: 2009-02-09
Filing date: 2010-02-09
Publication date: 2010-08-12
Also published as: CN102387902A; JP2010179627A; TWI410315B; TW201038383A

Abstract

Disclosed is a method for manufacturing foamable thermoplastic resin particles. This manufacturing method comprises: a step wherein thermoplastic resin is supplied to a resin supply device to which is attached a granulation die having at least a die main body that has a resin discharge face, and said resin is melted and kneaded; a step wherein a foaming agent is injected into the aforementioned thermoplastic resin while the aforementioned thermoplastic resin is moved toward the aforementioned granulation die, thus forming a foaming agent-containing resin; and a step wherein the aforementioned foaming agent-containing resin, which is discharged from a nozzle opened to the resin discharge face of the aforementioned die main body, is cut by a cutter in a cooling medium to obtain foamable thermoplastic resin particles. The foamable thermoplastic resin particles are obtained while controlling the temperature of the aforementioned die main body to a temperature range that is 115-200°C higher than the molten resin temperature of the foaming agent-containing resin.

Description

Method for producing foamable thermoplastic resin particles, method for producing thermoplastic resin foamed particles, and method for producing thermoplastic resin foam molded article

The present invention relates to a method for producing foamable thermoplastic resin particles for producing foamable thermoplastic resin particles by an underwater hot cut method, a method for producing thermoplastic resin foam particles, and a method for producing a thermoplastic resin foam molded article.
This application claims priority based on Japanese Patent Application No. 2009-027299 for which it applied to Japan on February 09, 2009, and uses the content here.

Conventionally, as a method for producing expandable thermoplastic resin particles for producing expandable thermoplastic resin particles by an underwater hot cut method, for example, there are techniques disclosed in Patent Documents 1 to 3.
Patent Document 1 discloses a method for producing a foamed styrene polymer having a molecular weight Mw exceeding 170000 g / mol. This method is a method in which a blowing agent-containing styrene polymer melt having a temperature of at least 120 ° C. is conveyed through a die plate having a hole having a hole diameter of 1.5 mm or less at a die outlet, and then the extrudate is granulated. is there.

In Patent Document 2, a resin discharge surface provided in contact with a water flow and a circumference of a virtual circle on the resin discharge surface are arranged, communicated with a cylinder of an extruder and opened to the resin discharge surface. A plurality of nozzles, a heat insulating material provided on a resin discharge surface inside the circumference where the nozzles are disposed, and provided in the vicinity of the resin discharge surface so as to extend outward through the center of the circumference. A granulating die comprising a plurality of cartridge heaters, a granulating apparatus, and a method for producing expandable thermoplastic resin particles using the same are disclosed.

In Patent Document 3, a foaming agent is press-fitted into a thermoplastic resin melted in an extruder, and the foaming agent-containing molten resin is directly extruded into a cooling liquid from a large number of small holes in a die attached to the tip of the extruder. At the same time as extruding, the extrudate is cut with a high-speed rotary blade, and the extrudate is cooled and solidified by contact with a liquid, thereby producing a thermoplastic resin expandable particle. This method is a manufacturing method in which the foaming agent-containing molten resin has a shear rate of 12000 to 35000 sec ⁻¹ when passing through the small hole land portion of the die and the apparent melt viscosity of the resin is 100 to 700 poise. is there.

JP 2005-534733 A WO2008 / 102874 WO2005 / 028173

When producing expandable thermoplastic resin particles by an underwater hot cut method, a molten resin added with a blowing agent is extruded into water from a number of nozzles, and immediately after that, the molten resin is cut into resin particles. However, since the tip end face of the die is in contact with the circulating water, heat is taken away. As a result, the resin discharged from the nozzle is solidified, the nozzle is blocked, and the production efficiency of the resin particles tends to decrease. Therefore, in the prior art, by controlling the temperature inside the die appropriately, foaming thermoplastic resin particles are produced while preventing clogging of the nozzle.

Patent Document 1 describes in paragraph 0021 that “the temperature of the die plate is preferably in a range of 20 to 100 ° C. higher than the temperature of the foaming agent-containing polystyrene melt”. In Table 2 of paragraph 0036, in Example 2 for producing expandable polystyrene granules, the die plate temperature is 180 to 240 ° C. (−20 ° C. to + 40 ° C. relative to the melting temperature) with respect to the melting temperature 200 ° C. The manufacturing example set to) is described.
However, as described in Patent Document 1, continuous production of expandable thermoplastic resin particles by the underwater hot-cut method is performed under the condition that the die plate temperature is set to be 20 to 100 ° C. higher than the molten resin temperature. Even if it is attempted, the small holes of the die are blocked, and it is impossible to continuously produce foamable thermoplastic resin particles having a small particle size.

In Patent Document 2, in Table 1 of Paragraph 0053, when the extrusion resin temperature is 170 ° C., there is a production example in which the die holding temperature is set to 270 to 280 ° C. (+100 to + 110 ° C. with respect to the extrusion resin temperature). Are listed.
As described in Patent Document 2, when the die holding temperature is set to +100 to + 110 ° C. with respect to the extrusion resin temperature, it is possible to continuously produce expandable thermoplastic resin particles by an underwater hot cut method. . However, the foamable thermoplastic resin particles obtained are mixed with larger particles, and it is difficult to obtain foamable thermoplastic resin particles having a small particle size.
Further, the foamable thermoplastic resin particles obtained in the above production examples have many voids inside the particles. As a result, when a foamed molded article is produced by in-mold foam molding of the foamable thermoplastic resin particles after preliminary foaming, the strength of the produced foam molded article is lowered.

In Patent Document 3, the foaming agent-containing molten resin has a shear rate of 12000 to 35000 sec ⁻¹ when passing through the small hole land portion of the die, and the resin has an apparent melt viscosity of 100 to 700 poise. . Paragraph 0027 describes that the resin temperature of the foamable resin in the die introduction part is adjusted to be 50 to 100 ° C. higher than the melting point of the resin.
However, even if an attempt was made to continuously produce expandable thermoplastic resin particles by the underwater hot-cut method under the conditions described in Patent Document 3, the small holes of the dies were closed, and the particle size was uniform with small particles. The foamable thermoplastic resin particles cannot be produced continuously.

The present invention has been made in view of the above circumstances, and in the production of expandable thermoplastic resin particles by an underwater hot cut method, it is possible to continuously produce expandable thermoplastic resin particles having a small particle size and a uniform particle size. An object of the present invention is to provide a simple manufacturing method.

In order to solve the above problems, the present invention employs the following means.
The method for producing expandable thermoplastic resin particles of the present invention includes a step of supplying a thermoplastic resin to a resin supply device having a granulation die having at least a die body having a resin discharge surface, and melt-kneading the thermoplastic resin. A step of forming a foaming agent-containing resin by injecting a foaming agent into the thermoplastic resin while moving the plastic resin toward the granulation die; and a nozzle that is opened on the resin discharge surface of the die body. Cutting the foaming agent-containing resin in a cooling medium with a cutter to obtain expandable thermoplastic resin particles.
In this method for producing expandable thermoplastic resin particles, the temperature of the die body is controlled so that the temperature of the die body is 115 ° C. to 200 ° C. higher than the molten resin temperature of the foaming agent-containing resin. obtain.

The method for producing foamed thermoplastic resin particles according to the present invention includes a step of supplying a thermoplastic resin to a resin supply apparatus having a granulation die having at least a die body having a resin discharge surface, and melt-kneading the thermoplastic resin. A step of injecting a foaming agent into the thermoplastic resin while moving the resin toward the granulation die to form a foaming agent-containing resin, and discharging from a nozzle opened in the resin discharge surface of the die body Cutting the foaming agent-containing resin in a cooling medium with a cutter to obtain foamable thermoplastic resin particles, and pre-foaming the foamable thermoplastic resin particles to obtain thermoplastic resin foam particles. .
In this method for producing thermoplastic resin expanded particles, expandable thermoplastic resin particles are obtained while controlling the temperature so that the temperature of the die main body is 115 ° C. to 200 ° C. higher than the molten resin temperature of the foam-containing resin. .

The method for producing a thermoplastic resin foam-molded article of the present invention includes a step of supplying a thermoplastic resin to a resin supply apparatus having a granulation die having at least a die body having a resin discharge surface, and melt-kneading the thermoplastic resin. A step of forming a foaming agent-containing resin by injecting a foaming agent into the thermoplastic resin while moving the plastic resin toward the granulation die; and a nozzle that is opened on the resin discharge surface of the die body. Cutting the foaming agent-containing resin in a cooling medium with a cutter to obtain foamable thermoplastic resin particles, pre-foaming the foamable thermoplastic resin particles to obtain thermoplastic resin foam particles, And obtaining a thermoplastic resin foam molded body by foam-molding the thermoplastic resin foam particles in a mold.
In this method for producing a thermoplastic resin foam molded article, the temperature of the die body is controlled so that the temperature of the die body is 115 ° C. to 200 ° C. higher than the molten resin temperature of the foaming agent-containing resin. A method for producing a thermoplastic resin foam-molded article is provided.

In the present invention, in the production of expandable thermoplastic resin particles by the underwater hot cut method, while controlling the temperature so that the temperature of the die body is 115 ° C. to 200 ° C. higher than the molten resin temperature of the foaming agent-containing resin, Expandable thermoplastic resin particles are obtained. As a result, foamable thermoplastic resin particles having a small particle size and a uniform particle size can be continuously produced.
Furthermore, the foamable thermoplastic resin particles obtained by the present invention have few voids inside the particles. Therefore, when the foamable thermoplastic resin particles are produced by in-mold foam molding to produce a foam molded article, the mechanical strength of the foam molded article can be improved.

It is a block diagram of the granulation apparatus which concerns on embodiment of this invention. It is a sectional side view showing the schematic structure of the granulation die concerning the embodiment of the present invention. It is a side view which shows the resin discharge surface of the die main body of FIG. It is a figure which shows an example of the arrangement | positioning state of a nozzle. It is a figure which shows an example of the arrangement | positioning state of the nozzle which concerns on the modification of embodiment of this invention. This figure corresponds to FIG. It is an enlarged image of the cross section of the expandable polystyrene-type resin particle manufactured in Example 1 of this invention. 4 is an enlarged image of a cross section of an expandable polystyrene resin particle produced in Comparative Example 2. FIG.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a block diagram showing an example of a granulating apparatus used in the manufacturing method of the present invention, FIG. 2 is a side sectional view showing an example of the granulating die, and FIG. 3 is a resin discharge surface of the die body of FIG. FIG. 4 is a diagram showing an arrangement state of nozzles.

As shown in FIGS. 1 and 2, the granulating apparatus T according to the present embodiment is a granulating apparatus for granulating foamable thermoplastic resin particles by an underwater hot cut method.
The granulating apparatus T includes an extruder 2 (resin supplying apparatus) having a granulating die 1 attached to the tip thereof, and a resin discharged from the nozzle 15 of the granulating die 1 (in this embodiment, a foaming agent-containing resin). 20) and a chamber 4 for bringing a water flow into contact with the resin discharge surface 13 of the granulation die 1. The chamber 4 is connected to a conduit 5 for flowing a cooling medium such as circulating water (hereinafter referred to as water). One end (upstream side of the chamber 4) of the pipe line 5 is connected to a water tank 7 through a water pump 6. On the other hand, the other end (downstream side of the chamber 4) of the pipe line 5 is connected to a dehydration processing unit 8 that separates foamed thermoplastic resin particles from the circulating water and dehydrates and dries them. The expandable thermoplastic resin particles separated by the dehydration processing unit 8 and dehydrated and dried are sent to the container 9. Reference numeral 21 is a hopper, 22 is a blowing agent supply port, and 23 is a high-pressure pump.
In the granulation apparatus T and the granulation die 1, the side from which the resin is discharged is referred to as “front” and “front end”, and the opposite side is defined as “rear” and “rear end” in the following description. Use.

As shown in FIGS. 2 and 3, the granulation die 1 includes a die body 10 (also referred to as a die plate) and a die holder 11 (also referred to as a diverter) fixed to the tip side (right side in the drawing) of the extruder 2. Called). The die body 10 is fixed to the tip end side of the die holder 11 with a plurality of bolts 12.
The die holder 11 is provided in communication with the cylinder of the extruder 2, and a rear end side flow path 11 a and a front end side flow path 11 b are formed in that order from the rear end side toward the front end side. The die body 10 is formed with a conical convex portion 10a that protrudes rearward at the center of the rear end surface. In a state where the die body 10 and the die holder 11 are connected, the conical convex portion 10a of the die body 10 is inserted into the distal end side flow passage 11b of the die holder 11 with a predetermined gap.
That is, the foaming agent-containing resin 20 passes through the rear end side flow passage 11a of the die holder 11, flows along the peripheral surface of the conical convex portion 10a in the front end side flow passage 11b, and opens to the rear end face of the die body 10. It communicates with a plurality of resin flow paths 14 (described later).

The die body 10 has a resin discharge surface 13 that comes into contact with the water flow at the tip surface thereof, and a plurality of resin flow paths 14 for transferring the foaming agent-containing resin 20 extruded from the extruder 2 toward the resin discharge surface 13. A plurality of nozzles 15 provided at the tips of the plurality of resin flow paths 14 and opening in the resin discharge surface 13, a heat insulating material 16 provided at the center position of the resin discharge surface 13, and an extruder more than the resin discharge surface 13. A cartridge heater 17 for warming the resin discharge surface 13 and the resin flow path 14 and a short heater 18 for warming the die body 10 are provided at a position on the second side.
The cartridge heater 17 and the short heater 18 can be appropriately selected from conventionally known cartridge heaters according to the size and shape of the die body 10. For example, as the cartridge heater 17 and the short heater 18, a heating wire (nichrome wire) wound around a rod-shaped ceramic is inserted into a pipe (heat-resistant stainless steel), and the gap between the heating wire and the pipe is highly thermally conductive and highly insulating. It is possible to use a bar heater with a high power density, which is encapsulated with an excellent material (MgO). The cartridge heater 17 and the short heater 18 may be a cartridge heater with two lead wires on one side, or a cartridge heater (seeds heater) with one lead wire on each side. A cartridge heater having two lead wires on one side is more preferable because it has a higher power density than a cartridge heater having one lead wire on each side.

The resin discharge surface 13 of the die body 10 is provided with a heat insulating material 16 having a circular cross section at the center thereof, and discharge ports of a plurality of nozzles 15 are provided along the concentric circles on the radially outer side of the heat insulating material 16. The central portion of the resin discharge surface 13 where the heat insulating material 16 and the plurality of nozzles 15 are arranged is designed to come into contact with water inside the chamber 4.

The plurality of resin flow paths 14 have a circular cross section, extend in a direction perpendicular to the resin discharge surface 13, and have a circumference (centered on the resin discharge surface 13) centered on the central axis of the die body 10. Are arranged at regular intervals along the circumference. In the present embodiment, eight resin flow paths 14 are provided, and the central angle between the resin flow paths 14 adjacent in the circumferential direction of the circumference is 45 °. As described above, each resin flow path 14 communicates with the front end side flow path 11 b of the die holder 11.

The plurality of nozzles 15 are arranged at predetermined intervals along the circumference drawn on the resin discharge surface 13. As shown in FIG. 4, specifically, one nozzle 15 is a nozzle unit in which a plurality of

single nozzles

15a, 15b, 15c,... This is called a “nozzle”). As a method for arranging the

single nozzles

15a, 15b, 15c,..., For example, a method in which a large number of small nozzles are arranged on a plurality of small circles can be adopted. However, the arrangement is not limited to such an arrangement.

The heat insulating material 16 is provided on the resin discharge surface 13 inside the circumference where the plurality of nozzles 15 are arranged. This heat insulating material 16 is for suppressing the temperature drop of the die body 10 so that the heat of the die body 10 does not escape to the water in the chamber 4. As the heat insulating material 16, it is preferable to use a heat insulating material having water resistance and a high surface hardness. For example, a heat insulating material excellent in heat resistance and heat insulating performance that does not cause deformation or the like even when in contact with the high-temperature die body 10 is disposed, and this is covered with a waterproof resin such as a fluororesin excellent in heat insulating performance, On the resin discharge surface 13 side, a laminated heat insulating material 16 in which materials having high surface hardness such as stainless steel and ceramics are sequentially laminated can be used.

Each of the cartridge heater 17 and the short heater 18 is a rod heater. The cartridge heater 17 is located closer to the resin discharge surface 13 than the short heater 18 in the front-rear direction of the granulation die 1.
The cartridge heater 17 is disposed on both sides of the circumferential direction of the resin flow path 14 in a state of crossing the circumference with the longitudinal direction thereof directed in the radial direction of the circumference. The cartridge heater 17 heats the resin discharge surface 13, the nozzle 15, and the resin flow path 14 in the vicinity of the resin discharge surface 13. Eight cartridge heaters 17 according to this embodiment are provided with a predetermined central angle (here, an angle of 45 °) in the circumferential direction. That is, the individual nozzles 15 are arranged so as to be sandwiched between the two cartridge heaters 17 from the circumferential direction of the circumference.

The cartridge heater 17 is provided in the vicinity of the resin discharge surface 13, that is, within a predetermined heater depth range from the resin discharge surface 13 toward the extruder 2 side. The heater depth refers to the distance from the resin discharge surface 13 to the center of the cartridge heater 17 for surface heating. A smaller heater depth is preferable as long as the processed surface of the die and the durability are not affected, and a smaller nozzle depth is preferable because the effect of suppressing clogging of the nozzle is increased. That is, the heater depth is preferably in the range of 10 to 50 mm. If the heater depth is less than 10 mm, there is a possibility that the processed surface of the die and the durability may be hindered. If the heater depth exceeds 50 mm, the nozzle clogging suppression effect may be reduced. A more preferable heater depth range is 15 to 30 mm.

The diameter of the cartridge heater 17 is preferably small as long as the heat generation capacity can be secured in order to secure a wide cross-sectional area of the resin flow path and increase the number of nozzles. That is, the diameter of the cartridge heater 17 is preferably 15 mm or less. However, if the diameter of the cartridge heater 17 is less than 10 mm, it is difficult to secure a necessary heat generation capacity, and the heater becomes expensive. Therefore, the diameter of the cartridge heater 17 is preferably 10 mm to 15 mm, and more preferably 10 mm to 12 mm.
The length dimension of the cartridge heater 17 is such that, in the radial direction of the die main body 10, the die main body 10 extends from a position extending to the center side from the arranged nozzle 15 (at least a position where the tip of the cartridge heater 17 is centered from the nozzle 15). It is the length to the position of the substantially outer periphery.

The same number (8) of short heaters 18 as the number of cartridge heaters 17 are arranged on the rear side with a predetermined interval from each cartridge heater 17. The short heater 18 heats the rear end side of the resin flow path 14. The length of the short heater 18 is shorter than that of the cartridge heater 17.

The granulation die is provided with

temperature measuring elements

19A and 19B for measuring the temperature of the die body and the temperature of the molten resin. The first temperature measuring body 19A measures the temperature at the center of the die body 10 (temperature of the die body: die holding temperature). The second temperature measuring element 19 </ b> B measures the molten resin temperature (and resin pressure) of the foaming agent-containing resin flowing in the die holder 11.

A method for producing expandable thermoplastic resin particles, thermoplastic resin expanded particles, and a thermoplastic resin foam molded article using the granulating apparatus T described above will be described.
The extruder 2 (resin supply device) used in the granulating apparatus T shown in FIG. 1 can be used by appropriately selecting from various types of conventionally known extruders according to the type of resin to be granulated. For example, either an extruder using a screw or an extruder not using a screw can be used. Examples of the extruder using a screw include a single-screw extruder, a multi-screw extruder, a vent-type extruder, and a tandem extruder. Examples of the extruder that does not use a screw include a plunger type extruder and a gear pump type extruder. Any of these extruders can use a static mixer. Among these extruders, an extruder using a screw is preferable from the viewpoint of productivity. Moreover, the chamber 4 which accommodated the cutter 3 can also use the conventionally well-known thing used in the hot cut method.

In the present invention, the type of the thermoplastic resin is not limited. For example, a polystyrene resin, a polyethylene resin, a polypropylene resin, a polyester resin, a vinyl chloride resin, an ABS resin, an AS resin, or the like can be used alone or in combination of two or more. Furthermore, it is also possible to use a recovered resin of a thermoplastic resin obtained after being used once as a resin product. In particular, polystyrene resins such as amorphous polystyrene (GPPS) and high impact polystyrene (HIPS) are preferably used. Examples of polystyrene resins include homopolymers of styrene monomers such as styrene, α-methylstyrene, vinyltoluene, chlorostyrene, ethylstyrene, i-propylstyrene, dimethylstyrene, bromostyrene, and copolymers thereof. Etc. In particular, a polystyrene resin containing 50% by mass or more of styrene is preferable, and polystyrene is more preferable.
The polystyrene resin may be a copolymer of the styrene monomer having the styrene monomer as a main component and a vinyl monomer copolymerizable with the styrene monomer. Examples of such vinyl monomers include methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, alkyl (meth) acrylates such as cetyl (meth) acrylate, (meth) acrylonitrile, dimethyl maleate, Examples include dimethyl fumarate, diethyl fumarate, ethyl fumarate, and bifunctional monomers such as divinylbenzene and alkylene glycol dimethacrylate.
If the polystyrene resin is the main component, other resins may be added. Examples of the resin to be added include diene rubbery heavy polymers such as polybutadiene, styrene-butadiene copolymer, and ethylene-propylene-nonconjugated diene three-dimensional copolymer in order to improve the impact resistance of the foamed molded product. There is a rubber-modified polystyrene resin (high impact polystyrene) to which coalescence is added. Further, there are polyethylene resins, polypropylene resins, acrylic resins, acrylonitrile-styrene copolymers, acrylonitrile-butadiene-styrene copolymers, and the like. When producing expandable polystyrene resin particles using the method for producing expandable thermoplastic resin particles of the present invention, as a polystyrene resin used as a raw material, commercially available ordinary polystyrene resin, suspension polymerization method, etc. Polystyrene resins (hereinafter referred to as virgin polystyrene) that are not recycled raw materials such as polystyrene resins newly produced by the method can be used. Furthermore, a recycled raw material obtained by regenerating a used polystyrene-based resin foam molded article can be used. This recycled material can be used after collecting used polystyrene resin foam moldings such as fish boxes, household appliance cushions, food packaging trays, etc., and recycled by the limonene dissolution method or heating volume reduction method. it can. In addition to recycled materials such as those mentioned above, non-foamed materials collected separately from household electrical appliances (eg, televisions, refrigerators, washing machines, air conditioners) and office equipment (eg, copiers, facsimiles, printers, etc.) It is also possible to use a polystyrene-based resin molded body that has been pulverized, melt-kneaded and re-pelletized.

As shown in FIGS. 1 and 2, when producing expandable thermoplastic resin particles using the granulating apparatus T described above, the following steps 1 to 5 are performed in order.
(Step 1) A thermoplastic resin is supplied from an hopper 21 to an extruder 2 having a granulation die 1 attached to the tip, and is melted and kneaded.
(Step 2) While moving the thermoplastic resin toward the granulation die 1, the foaming agent is pressed into the thermoplastic resin from the foaming agent supply port 22 by the high-pressure pump 23. That is, the foaming agent-containing resin 20 is formed by mixing the foaming agent and the thermoplastic resin.
(Step 3) The foaming agent-containing resin 20 is sent from the tip of the extruder 2 through the die holder 11 to the resin flow path 14 of the die body 10.
(Step 4) The foaming agent-containing resin 20 sent through the resin flow path 14 is discharged from each nozzle 15 opened in the resin discharge surface 13 of the die body 10.
(Step 5) The foaming agent-containing resin 20 discharged from each nozzle 15 is immediately cut by the rotary blade of the cutter 3 in the water flow (in the cooling medium) of the chamber 4.

During granulation of the foaming agent-containing resin 20, the heaters are turned on and off so that the temperature of the die body 10 is in a range 115 ° C. to 200 ° C. higher than the molten resin temperature of the foaming agent-containing resin 20. Thus, granulation is performed by an underwater hot cut method while controlling the temperature of the die body 10. The temperature of circulating water as a cooling medium is adjusted to 10 to 60 ° C.
The molten resin temperature refers to the temperature of the foaming agent-containing resin 20 that has flowed into the die holder 11 from the tip of the extruder 2. In the present embodiment, the molten resin temperature is measured by the second temperature measuring element 19B.

Thus, temperature control is performed so that the temperature of the die body 10 is 115 ° C. to 200 ° C. higher than the molten resin temperature, preferably 120 ° C. to 180 ° C., more preferably 120 ° C. to 180 ° C. To do. Thereby, in manufacture of the expandable thermoplastic resin particle by the underwater hot cut method, the expandable thermoplastic resin particle with a uniform particle diameter can be continuously produced. Moreover, when granulation is performed under the above-described conditions, voids inside the obtained expandable thermoplastic resin particles are reduced. Thereby, the mechanical strength of the foamed molded product produced by in-mold foam molding of the foamable thermoplastic resin particles can be improved.
When the temperature of the die body is less than the molten resin temperature + 115 ° C., the nozzle 15 is closed when the foamable thermoplastic resin particles are continuously produced, and the resin pressure in the die body fluctuates. As a result, it may be impossible to continuously produce foamable thermoplastic resin particles having a small particle size and a uniform particle size. Moreover, the void of the cross section of the foamable thermoplastic resin particle obtained increases. As a result, there is a possibility that the mechanical strength of the foamed molded product produced by foam-molding the foamable thermoplastic resin particles in the mold is lowered.
When the temperature of the die body 10 exceeds the molten resin temperature + 200 ° C., the foamable thermoplastic resin particles obtained are finely foamed. As a result, there is a possibility that it is impossible to continuously produce small and uniform particles.

If the temperature of the circulating water that is the cooling medium is less than 10 ° C., the heat removed from the resin discharge surface 13 by the circulating water increases. As a result, it becomes difficult to maintain the temperature of the granulation die 1. On the other hand, when the temperature of circulating water exceeds 60 degreeC, cooling of the cut resin will become inadequate. As a result, it becomes difficult to suppress the fine foaming of the resin particles. The temperature of the circulating water is preferably in the range of 20 ° C to 40 ° C, more preferably in the range of 25 ° C to 35 ° C.

The foaming agent-containing resin 20 cut into particles in the chamber 4 becomes substantially spherical foaming thermoplastic resin particles. The foamable thermoplastic resin particles are conveyed in the pipe line 5 according to the water flow and reach the dehydration processing unit 8. Here, the foamable thermoplastic resin particles are separated from the circulating water, dehydrated and dried, and the separated water is sent to the water tank 7. The foamable thermoplastic resin particles separated by the dehydration processing unit 8, dehydrated and dried are sent to the container 9 and accommodated in the container.

The foaming agent is not limited. For example, normal pentane, isopentane, cyclopentane, cyclopentadiene and the like can be used alone or in admixture of two or more. Further, normal butane, isobutane, propane and the like can be mixed and used with the pentane as a main component. In particular, pentanes are preferably used because they tend to suppress foaming of particles when discharged from a nozzle into a water stream.

The foamable thermoplastic resin particles refer to resin particles that are formed into a granular shape, preferably a small spherical shape, by adding a foaming agent to a thermoplastic resin. The foamable thermoplastic resin particles can be used to produce a foamed resin molded body having a desired shape. First, the foamable thermoplastic resin particles are preliminarily foamed by heating in free space. The pre-expanded particles are put into a cavity of a mold having a cavity having a desired shape, and the pre-expanded particles are fused by steam heating. Thereafter, a foamed resin molded body having a desired shape can be produced by releasing the mold.

As described above, in the present invention, in the production of expandable thermoplastic resin particles by the underwater hot cut method, the temperature of the die body is set to a range 115 ° C. to 200 ° C. higher than the molten resin temperature of the foaming agent-containing resin. While controlling, the foamable thermoplastic resin particles are obtained. Thereby, the foamable thermoplastic resin particle with a uniform particle diameter can be continuously produced.
Moreover, in the foamable thermoplastic resin particle obtained by this invention, the void inside a particle | grain decreases. Thereby, the mechanical strength of the foamed molded article produced by in-mold foam molding of the obtained foamable thermoplastic resin particles can be improved.

The detailed production conditions in the production method of the present invention can be set as appropriate according to the type of resin to be used, but the following items are preferable as production conditions. (1) The hole diameter of the die body 10n nozzle 15 is preferably in the range of 0.2 mm to 2.0 mm, more preferably in the range of 0.3 mm to 1.0 mm, and still more preferably in the range of 0.4 mm to 0.7 mm. (2) The particle diameter of the foamable thermoplastic resin particles obtained is preferably in the range of 0.3 mm to 2.0 mm, more preferably in the range of 0.5 mm to 1.4 mm, and in the range of 0.7 mm to 1.2 mm. Is more preferable. (3) When the expandable thermoplastic resin particles are expandable polystyrene resin particles, the weight average molecular weight Mw of the polystyrene resin particles is preferably in the range of 120,000 to 400,000, more preferably in the range of 120,000 to 270,000. . (4) The foaming agent content in the expandable thermoplastic resin particles is preferably in the range of 1 to 10% by mass, more preferably in the range of 3 to 8% by mass, and still more preferably in the range of 4 to 6% by mass. (5) The foaming agent is preferably normal pentane, isopentane, or mixed pentane mixed at any ratio. In the case of mixed pentane, the composition is preferably in the range of isopentane: normal pentane = 10: 90 to 80:20, and more preferably in the range of isopentane: normal pentane = 80: 80 to 60:40. (6) The average cell diameter of the expanded thermoplastic resin particles obtained by pre-expanding expandable thermoplastic resin particles is preferably in the range of 30 μm to 500 μm, more preferably in the range of 50 μm to 300 μm, and in the range of 100 μm to 250 μm. Is more preferable.

As described above, in the method for producing expandable thermoplastic resin particles of the present invention, the temperature of the die body 10 is set to 115 ° C. to 200 ° C. higher than the molten resin temperature, preferably 120 ° C. to 180 ° C. higher. Control. Thereby, in manufacture of the expandable thermoplastic resin particle by the underwater hot cut method, the expandable thermoplastic resin particle with a uniform particle diameter can be continuously produced. The continuous production refers to producing expandable thermoplastic resin particles continuously for at least 12 hours or more, preferably 24 hours or more from the start of granulation. According to the production method of the present invention, in continuous production for 48 hours or more, the decrease in the nozzle opening ratio is 50% or less, and the change rate of the particle size of the obtained expandable thermoplastic resin particles is 20% or less. Resin particles can be produced continuously.
In addition, the following effects can be obtained by adopting the above-described preferable production conditions (1) to (6). (A) The amount of foaming agent can be reduced to obtain the same expansion ratio. (B) Decrease in foamability due to aging is small and bead life is long. (C) It is excellent in low-pressure moldability (heating energy for obtaining a foam-molded product is small and energy is saved). (D) It has sufficient opportunity strength. (E) A foam molding ratio of 5 to 67 times is obtained.

Next, a modification of the embodiment of the present invention will be described based on the drawings. However, the same reference numerals are used for the same or similar members and portions as those of the above-described embodiment, and the description thereof is omitted, and a configuration different from that of the above-described embodiment is described.
FIG. 5 is a diagram illustrating an arrangement state of nozzles according to a modification of the present embodiment, and corresponds to FIG.
The resin flow path 14A according to the modification shown in FIG. 5 has a trapezoidal cross section, and a nozzle 15 in which a plurality of

single nozzles

15a, 15b, 15c,... Are arbitrarily arranged within the trapezoidal range is provided. It has been.

Slopes

14 a and 14 b (straight line portions) that form the outline of the resin flow path 14 </ b> A are disposed substantially parallel to the longitudinal direction of the cartridge heater 17. In this modification, the

slopes

14 a and 14 b of the resin flow path 14 A having a trapezoidal cross section are equidistant from the cartridge heater 17. Therefore, the area of the resin flow path that is evenly heated by the cartridge heater 17 is increased, and the resin flow path is heated more uniformly than the resin flow path having a circular cross section, so that nozzle clogging can be further reduced.

[Example 1]
In Example 1, the granulating die 1 shown in FIGS. 2 and 3 was attached to the granulating apparatus T shown in FIG. 1 to produce expandable polystyrene resin particles.
A granulation die was attached to a single screw extruder having a diameter of 90 mm (L / D = 35).
The granulation dies used consisted of eight nozzle units (a plate having 25 nozzles with a diameter of 0.6 mm and a land length of 3.0 mm) arranged on the circumference of the resin discharge surface, and the resin discharge surface side. Eight cartridge heaters (diameter: 12 mm in diameter) arranged radially across the circumference at a heater depth (distance from the resin discharge surface) of 15 mm so as to sandwich the resin flow paths leading to the nozzle unit from both sides And a heat insulating material attached to the center of the resin discharge surface. Further, as shown in FIG. 2, a plurality of

temperature measuring elements

19A and 19B are arranged, and the area is divided into two parts: four heaters on the circulating water inflow side and four heaters on the circulating water outflow side of the die body. The temperature of the die body (die holding temperature) was kept at 300 ° C.

In Example 1, the following steps were performed in order.
(Step 1) Polystyrene resin (manufactured by Toyo Styrene Co., Ltd., trade name “HRM10N”, Vicat softening point temperature: 102 ° C.) 100 parts by mass of finely powdered talc 0.3 parts by mass previously mixed in a tumbler mixer, It was fed into the extruder at a rate of 130 kg per hour.
(Step 2) After setting the maximum temperature in the extruder to 220 ° C. and melting the resin, 6 parts by weight of pentane (isopentane / normal pentane = 20/80 mixture) with respect to 100 parts by weight of the resin as a foaming agent It was press-fitted from the middle of the extruder.
(Step 3) While the resin and the foaming agent were kneaded in the extruder, the foaming agent-containing molten resin was passed through a die holder (connecting portion between the extruder and the die body) and transported to the die body held at 300 ° C.
(Step 4) At the same time as extruding the foaming agent-containing molten resin into the chamber through which the cooling water of 30 ° C. circulates, a high-speed rotating cutter having 10 blades in the circumferential direction is brought into close contact with the die at 3300 revolutions per minute The extruded foaming agent-containing molten resin was cut.
(Step 5) The foaming agent-containing molten resin extruded from the cooling water was separated and dehydrated and dried to obtain spherical expandable polystyrene resin particles.
In the said process, the molten resin temperature in a die holder was 180 degreeC, and the discharge amount of the expandable polystyrene resin particle was 138 kg / h.
In the first hour after extrusion, the pressure of the resin introduction part to the granulation die was 10.0 MPa, the mass of 100 resin particles after drying was 0.0417 g, and the opening rate of the die was as good as 92.0%. It was a natural granulation environment.
Even at 48 hours after the start of extrusion, the pressure of the resin introduction part to the granulation die was 10.5 MPa, the mass of 100 resin particles after drying was 0.0426 g, and the die opening rate was 90.0%. Good granulation status was maintained. That is, in Example 1, it was confirmed that stable granulation was possible for 48 hours or more.

[Comparative Example 1]
Except that the temperature of the die body (die holding temperature) was 220 ° C., substantially spherical expandable polystyrene resin particles were obtained at a discharge rate of 138 kg / h in the same manner as in Example 1. The molten resin temperature in the die holder at this time was 180 ° C.
In Comparative Example 1, since the pressure of the resin introduction portion to the die reached the die pressure limit (25 MPa) within 1 hour from the start of extrusion, the extrusion was terminated. Since it was not able to extrude for 1 hour, evaluation was impossible.

[Comparative Example 2]
Except that the temperature of the die body was 290 ° C., substantially spherical expandable polystyrene resin particles were obtained at a discharge rate of 138 kg / h in the same manner as in Example 1. The molten resin temperature in the die holder at this time was 180 ° C.
In the first hour after extrusion, the pressure of the resin introduction part to the granulation die was 12.0 MPa, the mass of 100 resin particles after drying was 0.0446 g, and the opening rate of the die was 86.0%. It was a good granulation environment.
Even at 48 hours after the start of extrusion, the pressure of the resin introduction part to the granulation die was 13.0 MPa, the mass of 100 resin particles after drying was 0.0451 g, and the die opening rate was 85.0%. A good granulation environment was maintained. That is, in Comparative Example 2, it was confirmed that stable granulation was possible for 48 hours or more.

The following items were measured and evaluated during the production of the expandable polystyrene resin particles in Example 1 and Comparative Examples 1 and 2, and the obtained expandable polystyrene resin particles. The results are summarized in Table 1.

<Die opening rate>
The hole area ratio is defined by the following formula (1).
Formula (1) Opening ratio (opening ratio during extrusion of the discharge nozzle on the die surface) = number of openings / total number of nozzles of the die × 100 (%)
The discharge amount is defined by the following equation (2).
Formula (2) Discharge rate (kg / h) = total mass of all expandable particles cut out by a cutter per 1 h = number of holes x number of cuts x 1 grain mass = number of holes x number of cutter blades x number of cutter rotations x 1 grain mass From the formula (2), the number of holes can be defined by the following formula (3).
Formula (3) Number of apertures = discharge rate (kg / h) / [number of cutter blades × cutter rotation speed (rph) × 1 grain mass (kg / piece)]
From the equations (1) and (3), the hole area ratio can be calculated by the following equation (4).
Formula (4) Opening ratio (E) = Number of openings / total number of discharge nozzles x 100 (%)
= [Q / (N × R × 60 × (M / 100) / 1000)] / H × 100 (%)
[Q is the discharge rate (kg / h), N is the number of cutter blades, R is the number of revolutions of the cutter (rpm), M is 100 particles (g) (choose any 100 particles from the expandable particles, minimum scale 0 The value weighed with an electronic balance of .0001 g was taken as the mass of 100 grains), and H represents the total number of nozzles of the die. ]

<Evaluation criteria for hole area ratio>
The hole area ratio (E) was evaluated according to the following criteria.
A: 50% ≦ E
○: 40% ≦ E <50%
Δ: 30% ≦ E <40%
×: E <30%

<Observation of voids in expandable particles>
By cutting the expandable particles obtained in Example 1 and Comparative Example 2 with a razor blade and photographing the cut surface with a scanning electron microscope (S-3000N, manufactured by Hitachi, Ltd.) at a magnification of 70 times. The voids in the particles were observed.
FIG. 6 is an enlarged image of a cross section of the expandable polystyrene resin particles produced in Example 1 according to the present invention. FIG. 7 is an enlarged image of a cross section of the expandable polystyrene resin particles produced in Comparative Example 2.

<Manufacture of foam molding>
As described above, first, expandable polystyrene resin particles obtained at 48 hours after extrusion were allowed to stand at 20 ° C. for 1 day. Thereafter, with respect to 100 parts by mass of expandable polystyrene resin particles, 0.1 parts by mass of zinc stearate, 0.05 parts by mass of hydroxystearic acid triglyceride, and 0.05 parts by mass of monoglyceride stearate were added and mixed to obtain resin particle surfaces. Coated. Thereafter, the mixture was put into a small batch type pre-foaming machine (internal volume 40 L) and heated with water vapor with a blowing pressure of 0.05 MPa (gauge pressure) while stirring, and the bulk foaming factor was 50 times (bulk density 0.02 g / cm ³ ) pre-expanded particles were prepared.
Subsequently, the obtained pre-expanded particles were aged at 23 ° C. for 1 day. After that, an automatic molding machine (ACE-3SP type, manufactured by Sekisui Koki Co., Ltd.) with an outer dimension of 300 × 400 × 100 mm (thickness 30 mm) and a mold having a partition part of thickness 5 mm, 10 mm, and 25 mm inside. Was used to mold pre-expanded particles under the following molding conditions to obtain a foam-molded product having an expansion ratio of 50 times (density 0.02 g / cm ³ ).
Molding conditions (ACE-3SP QS molding mode)
Molding vapor pressure 0.08MPa (gauge pressure)
Mold heating 3 seconds One-side heating (pressure setting) 0.03 MPa (gauge pressure)
Reverse one heating 2 seconds Double-sided heating 12 seconds Water cooling 10 seconds Set extraction surface pressure 0.02 MPa

<Evaluation criteria for mold filling properties of pre-expanded particles>
The foamed molded product was visually observed, and the following evaluation was performed on the mold filling property.
(Double-circle): It fills up to the partition part 5mm thick.
○: Filling of the partition part with a thickness of 5 mm is sweet and excessive foam particles are observed, but the partition part is formed.
(Triangle | delta): The particle | grain defect | deletion by poor filling is seen in the partition part with thickness 5mm, and the partition part is not formed completely.
X: The partition part with a thickness of 5 mm is poorly filled, and no partition part is formed at all.

<Total mass of 100 particles>
In the expandable polystyrene resin particles, the total mass of 100 arbitrarily selected particles is preferably in the range of 0.02 to 0.09 g. When the total mass of 100 particles exceeds 0.09 g, it becomes difficult to fill the details of the molding die. As a result, there is a possibility that moldable molds are limited to simple shapes. On the other hand, when the total mass of 100 particles is less than 0.02 g, the productivity of the particles may be inferior. That is, a more preferable range is 0.04 to 0.06 g in the total mass of 100 particles. For resins other than polystyrene-based resins, a value obtained by multiplying the above range by the specific gravity of the resin is the range of the total mass of 100 preferable particles.

<Method for measuring bulk expansion ratio of pre-expanded particles>
The sufficiently dried pre-expanded particles were naturally dropped into a graduated cylinder (for example, 500 mL capacity) using a funnel. Thereafter, the pre-expanded particles were filled by hitting the bottom of the graduated cylinder until the volume of the pre-expanded particles became constant. The volume and mass of the pre-expanded particles at this time were measured, and the bulk expansion ratio of the pre-expanded particles was calculated by the following formula (5). The volume was read in units of 1 mL, and the mass was measured with an electronic balance having a minimum scale of 0.01 g. The resin specific gravity of the styrene resin was calculated as 1.0, and the bulk expansion factor was rounded off to the first decimal place.
Formula (5) Bulk expansion ratio (times) = volume of pre-expanded particles (mL) / mass of pre-expanded particles (g) × resin specific gravity

<Measurement method of expansion ratio of foamed molded product>
A test specimen for measurement (example 300 × 400 × 30 mm) was cut out from the foamed molded article that had been sufficiently dried, and the dimensions and mass of the test specimen were measured. The volume of the test piece was calculated based on the measured dimensions, and the foaming multiple of the foamed molded product was calculated by the following formula (6). The specific gravity of the styrene resin was 1.0.
Formula (6) Foaming multiple (times) = test piece volume (cm ³ ) / test piece mass (g) × resin specific gravity

<Measurement method of Vicat softening point>
A test piece having a size of 12.7 mm × 64 mm × 6.4 mm was molded at a cylinder temperature of 220 ° C. using an injection molding machine (IS-80CNV) manufactured by Toshiba Machine. Using this test piece, measurement was performed under the condition of a load of 50 N in accordance with JISK7206 (unit: ° C.).

<Strength evaluation>
The bending strength was measured by the method described in JIS A9511: 2006 “Foamed plastic heat insulating material”. In other words, using a Tensilon universal testing machine UCT-10T (Orientec Co., Ltd.), the test strip size is 75 mm × 300 mm × 30 mm, the compression speed is 10 mm / min, the tip jig is the pressure wedge 10R and the support base 10R, the fulcrum The distance was measured as 200 mm, and the bending strength was calculated by the following formula (7). The number of test pieces was three, and the average value was obtained.
Formula (7) Bending strength (MPa) = 3FL / 2bh ²
[F represents the maximum bending load (N), L represents the distance between supporting points (mm), b represents the width (mm) of the test piece, and h represents the thickness (mm) of the test piece. ]
In addition, as evaluation of bending strength, the value of bending strength was 0.28 MPa or more, and ○ was less than 0.28 MPa.

In Example 1 according to the present invention, the die pressure (die holding temperature) was maintained at 300 ° C., which is 120 ° C. higher than the molten resin temperature. And the nozzle opening rate remained high (see Table 1). That is, continuous operation for 48 hours or more was sufficiently possible.
In Example 1, the mass of 100 products after 1 hour of granulation was 0.0417 g, whereas the mass of 100 products after 48 hours was 0.0426 g (see Table 1). ). That is, the mass increase rate of the product in the continuous operation was as small as about 2%.
The expandable polystyrene resin particles obtained in Example 1 (see FIG. 6) are more voids in the particles (see FIGS. 6 and 7) than the resin particles obtained in Comparative Example 2 (see FIG. 7). The number of voids visible in the particles was small.
The foamed molded product obtained by pre-foaming the expandable polystyrene resin particles obtained in Example 1 and then in-mold foam-molding showed higher strength than that obtained in Comparative Example 2 (Table 1). See).

In contrast, in Comparative Example 1, the temperature of the die body (die holding temperature) was maintained at 200 ° C., which is 20 ° C. higher than the molten resin temperature. In Comparative Example 1, the nozzle quickly closed and the pressure increased to the upper limit of the die pressure resistance within one hour from the start of granulation, and the subsequent operation was not possible (see Table 1).

In Comparative Example 2, the temperature of the die body (die holding temperature) was maintained at 290 ° C., 110 ° C. higher than the molten resin temperature. In Comparative Example 2, the increase in the die pressure was gentle even after 48 hours from the start of granulation, the nozzle opening rate was high, and continuous operation was possible.
However, the foamable polystyrene resin particles obtained in Comparative Example 2 after 48 hours from the start of granulation have a mass of 100 particles that is as heavy as 0.0451 g when compared with the resin particles obtained in Example 1, The bulk density decreased and the particles became slightly large. Furthermore, in Comparative Example 2, the ratio of large particles having a particle size of 1.4 mm or more was as high as 0.5% (0.1% in Example 1), and the variation in particle size was large.
The expandable polystyrene resin particles (see FIG. 7) obtained in Comparative Example 2 had more voids in the particles than the resin particles obtained in Example 1 (see FIG. 6).
The foamed molded product obtained by pre-expanding the expandable polystyrene resin particles obtained in Comparative Example 2 and then in-mold foam molding showed lower strength than that obtained in Example 1.

According to the present invention, in the production of expandable thermoplastic resin particles by the underwater hot-cut method, it is possible to suppress the clogging of the die small holes with the passage of the extrusion time, and stably and uniformly expandable thermoplastic resin particles. Can be manufactured. The foamable thermoplastic resin particles obtained in the present invention are foam-molded into various shapes by an in-mold foam-molding method, and are used for the production of a foam-molded product used as a cushioning material, a heat insulating material or the like.

1 Die for granulation 2 Extruder (resin feeder)
3 Cutter 4 Chamber 6 Water Pump 10 Die Body 11 Die Holder 13

Resin Discharge Surface

14,

14A Resin Channel

14a, 14b Slope (Linear Part)
15 Nozzle 16 Heat insulating material 17 Cartridge heater 18

Short heater

19A, 19B Temperature measuring element T Granulator

Claims

A step of supplying a thermoplastic resin to a resin supply apparatus equipped with a granulation die having at least a die body having a resin discharge surface and melt-kneading the resin supply device;
A step of injecting a foaming agent into the thermoplastic resin while moving the thermoplastic resin toward the granulation die to form a foaming agent-containing resin;
Cutting the foaming agent-containing resin discharged from a nozzle opened in the resin discharge surface of the die body in a cooling medium with a cutter to obtain expandable thermoplastic resin particles. A manufacturing method of
A method for producing foamable thermoplastic resin particles, wherein foamable thermoplastic resin particles are obtained while controlling the temperature of the die body so that the temperature of the die body is 115 ° C to 200 ° C higher than the molten resin temperature of the foaming agent-containing resin.
A step of supplying a thermoplastic resin to a resin supply apparatus equipped with a granulation die having at least a die body having a resin discharge surface and melt-kneading the resin supply device;
A step of injecting a foaming agent into the thermoplastic resin while moving the thermoplastic resin toward the granulation die to form a foaming agent-containing resin;
Cutting the foaming agent-containing resin discharged from a nozzle opened in the resin discharge surface of the die body in a cooling medium with a cutter to obtain expandable thermoplastic resin particles;
A step of pre-foaming the foamable thermoplastic resin particles to obtain thermoplastic resin foam particles, and a method for producing thermoplastic resin foam particles,
A method for producing foamed thermoplastic resin particles, wherein foamable thermoplastic resin particles are obtained while controlling the temperature of the die main body to be in a range 115 ° C. to 200 ° C. higher than the molten resin temperature of the foaming agent-containing resin.
A step of supplying a thermoplastic resin to a resin supply apparatus equipped with a granulation die having at least a die body having a resin discharge surface and melt-kneading the resin supply device;
A step of injecting a foaming agent into the thermoplastic resin while moving the thermoplastic resin toward the granulation die to form a foaming agent-containing resin;
Cutting the foaming agent-containing resin discharged from a nozzle opened in the resin discharge surface of the die body in a cooling medium with a cutter to obtain expandable thermoplastic resin particles;
Pre-foaming the foamable thermoplastic resin particles to obtain thermoplastic resin foam particles;
A process for obtaining a thermoplastic resin foam molded article by foam-molding the thermoplastic resin foam particles in a mold, and a method for producing a thermoplastic resin foam molded article,
A method for producing a thermoplastic resin foam molded article for obtaining expandable thermoplastic resin particles while controlling the temperature of the die main body to be in a range of 115 ° C. to 200 ° C. higher than the molten resin temperature of the foaming agent-containing resin.