JP4160660B2 - Method for producing foam molded article - Google Patents

Description

【００３８】
【表２】

【００３９】
【発明の効果】
以上説明したように本発明方法は、第一加熱領域において上側から下側に向かって又は、下側から上側に向かって成形用スチームを供給して加熱した後、第二加熱領域において、第一加熱領域における成形用スチーム供給方向とは逆の方向に成形用スチームを供給して加熱して成形する方法を採用したことにより、ラインスピードを高めて成形した場合でも、成形用スチームにより発泡粒子を確実且つ均等に加熱することができ、成形用スチームの圧力を高めることなく発泡粒子の融着性に優れた成形体を得ることができる。このためラインスピードを高くした場合には成形用スチーム圧を高くしなければならなかった従来法のように、得られた成形体の養生に長い時間を要する等の問題がなく、ラインスピードを高めることができることと相まって、効率良く優れた成形体を得ることができる。
【００４０】
また第一加熱領域及び第二加熱領域において、成形用スチームを供給した側の反対側から吸引すると、更に効率よく成形用スチームによって発泡粒子を加熱することができる。更に、加熱領域の上流側で通路内のスチームを吸引するようにすると、発泡粒子を安定に供給することができ、安定して優れた成形体を得ることができる。更にまた本発明方法によれば、バッチ式成形法では困難であった長尺な成形体の製造が可能となるとともに、従来バッチ式成形法による製造が主体であったポリオレフィン系樹脂発泡成形体の生産性を大幅に向上することができ、自動成形も可能となるため、大幅なコストダウンが可能である。また、成形体表面に合成樹脂フィルムを積層した複合パネルの製造も連続して効率良く行うことができ、発泡粒子成形体を芯材とする複合パネルのコストダウンも図ることができる等の効果を有する。
【図面の簡単な説明】
【図１】本発明方法の実施に用いる成形装置の略図である。
【符号の説明】
２、３ ベルト
６ 発泡粒子
９ 通路
１０ 成形体
１１ チャンバー
１２ チャンバー
１３ チャンバー
１４ チャンバー
１５ チャンバー
１６ 冷却手段[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for producing a foam molded article.
[0002]
[Prior art]
Conventionally, as a method of molding synthetic resin foamed particles, a method of obtaining a molded body by filling the foamed particles in a mold, heating with foaming steam to secondary foam the foamed particles, and fusing the particles together ( Hereinafter, such a molding method is referred to as a batch molding method.) The polyolefin resin foamed particles are mainly molded by this batch molding method. On the other hand, there is also known a method of continuously forming foam particles by passing them through a heating region while being sandwiched between upper and lower belts (hereinafter, such a molding method is referred to as a continuous molding method). The method has been mainly used for molding styrene resin expanded particles. Since the continuous molding method has an advantage that a molded body can be continuously produced and a long molded body can be obtained as compared with the batch molding method, the present inventors have produced polyolefin resin expanded particles by the continuous molding method. We considered forming.
[0003]
As a continuous molding method of polystyrene resin expanded particles, a method in which expanded particles are heated by high frequency heating (Japanese Patent Publication No. Sho 41-1632), and a method in which foamed particles are heated by hot air (Japanese Patent Publication No. 47-42621). And a method of forming foamed particles by heating with steam (Japanese Patent Publication No. 52-2424) is known.
[0004]
However, the method using high-frequency heating as described in Japanese Patent Publication No. 41-1632 has a problem that the apparatus is large and expensive, and there is a risk of generating sparks during high-frequency irradiation, and the heating temperature range is narrow. It is not suitable as a heating means for polyolefin resin foamed particles that must be heated inside. In addition, the hot air heating method described in Japanese Patent Publication No. 47-42621 is also difficult to control the heating temperature and is difficult to uniformly heat because the heat capacity is smaller than steam. It was unsuitable as a heating means for continuously forming particles.
[0005]
On the other hand, the method by steam heating is also an effective method for polyolefin resin expanded particles, but the polyolefin resin expanded particles are obtained by continuous molding by steam heating as described in, for example, Japanese Examined Patent Publication No. 52-2424. When molding is attempted, the molding steam leaks to the foamed particle supply side, resulting in poor fusion of the particles due to insufficient heating, poor secondary foaming, etc., or when the steam leaks severely, the particles flow back to the supply side. There was a problem such as. The reason for this is considered to be due to the difference in secondary foaming performance between the polystyrene-based resin expanded particles and the polyolefin-based resin expanded particles. That is, the polystyrene resin is amorphous, the retention of the foaming agent used in the production of the foamed particles is good, and the foamed particles contain a few percent of the foaming agent. Secondary foaming of the foamed particles occurs at a relatively low temperature (usually 100 ° C. or less). For this reason, when the polystyrene resin expanded particles are continuously formed, before the expanded particles reach the heating region, a moderate secondary expansion occurs to close the gap between the particles, and the polystyrene resin expanded particles are 1.0 kg. Combined with the ability to mold with steam at a relatively low pressure of around / cm ² G, it is possible to easily prevent the steam from leaking to the particle supply side. It is done.
[0006]
On the other hand, the polyolefin resin is crystalline, and the foaming agent used in the production of the foamed particles escapes from the inside of the particles in a relatively short time. It is necessary to heat at a higher temperature than in the case of expanded polystyrene-based resin particles. For this reason, it is not easy to secondary foam the polyolefin resin in front of the heating region to the extent that leakage of steam can be prevented, and it is necessary to supply high-pressure steam to secondary foam the polyolefin resin. Therefore, even if the polyolefin resin foamed particles can be subjected to secondary foaming to some extent before the heating region, it is considered difficult to prevent high-pressure steam from leaking out only by the secondary foaming force of the foamed particles. In order to obtain a good molded product by secondarily foaming the foamed particles and fusing the particles together, the polyolefin resin foam particles that require higher pressure steam than the polystyrene resin foam particles are required. In this case, the molding steam is liable to leak, and as a result, the pressure of the molding steam is lowered and the foamed particles cannot be sufficiently heated to obtain a good molded product. However, when the temperature becomes violent, the foamed particles flow backward to the supply side, making it impossible to mold.
[0007]
In view of the above problems, as a method for continuously molding the polyolefin resin expanded particles, the present applicant: (1) In the expanded particle supply region, expand the expanded particles to 40 to 70% of the original bulk volume. A method of heating with steam after compression (Japanese Patent Laid-Open No. 9-104026), and a method of heating with steam after gradually compressing foamed particles with increased internal pressure in the foamed particle supply region (Japanese Patent Laid-Open No. 9-104026). -104027) or a further improvement of these methods, after compressing polyolefin resin expanded particles with a compression recovery rate of 80% or more, release part or all of the compression and then heat with molding steam (Japanese Patent Application No. 8-355665) was proposed.
[0008]
The polyolefin resin can be molded by the continuous molding method in the same manner as the polystyrene resin by the method previously proposed by the present applicant. As described above, the continuous molding method has an advantage that the production efficiency of the molded body is higher than that of the batch molding method, and there is an advantage that a long molded body can be obtained. In the continuous molding method, if the line speed of the production line is increased in order to further increase the molding efficiency, there arises a problem that the fusibility of the expanded particles is lowered. In order to solve such problems, it is sufficient to increase the molding steam pressure. However, if molding is performed with a higher molding steam pressure, a longer curing time is required to restore the dimensions of the resulting molded product. As a result, there was a problem that the molding efficiency could not be increased.
[0009]
The present invention has been made in view of the above points, and when continuously forming expanded particles such as polystyrene resin expanded particles and polyolefin resin expanded particles, the line speed is increased without increasing the molding steam pressure. An object of the present invention is to provide a method for producing a foamed molded product that can be molded and can efficiently obtain an excellent molded product.
[0010]
[Means for Solving the Problems]
That is, the method for producing a foamed molded article of the present invention supplies foamed particles between belts that are formed by being surrounded by a structural material and that continuously move along the upper and lower surfaces in a passage having a substantially rectangular cross section. Then, in the method for continuously producing the foamed molded article by sequentially passing the expanded particles through the heating region and the cooling region, the heating region includes a first heating region and a second heating region downstream thereof, In the first heating region, after supplying and heating the forming steam from the upper side to the lower side of the passage or from the lower side to the upper side, in the second heating region, the direction opposite to the steam supply direction in the first heating region A steam for forming is supplied and heated.
[0011]
In the method of the present invention, in the first heating region and the second heating region, it is preferable to suck steam in the passage from the side opposite to the steam supply side of the passage, and on the upstream side of the first heating region, the passage It is preferable to suck the inside. As the expanded particles, polyolefin resin expanded particles are particularly preferable.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the method of the present invention will be described with reference to the drawings.
FIG. 1 shows an example of a molding apparatus for carrying out the continuous molding method of polyolefin resin foamed particles according to the present invention. In the figure, 1 is a hopper storing foamed particles, and 2 is endlessly running between rolls 3a and 3b. The upper belt 4 is a lower belt that travels endlessly between the rolls 5a and 5b. The expanded particles 6 supplied from the hopper 1 are sandwiched between upper and lower belts 2 and 4 that travel endlessly, and are provided on upper and lower thickness regulating plates 7 and 8 and on both sides of the thickness regulating plates 7 and 8. While passing through a passage 9 having a space with a substantially rectangular cross section surrounded by a width regulating plate (not shown), the foamed particles 6 are fused and molded while being heated by molding steam. The body 10 is configured to be obtained.
[0013]
In the present invention, examples of the base material of the expanded particles 6 include polystyrene resins and polyolefin resins. Polystyrene resins include polystyrene, high impact polystyrene, poly-p-methylstyrene, styrene-maleic anhydride copolymer, styrene-acrylonitrile copolymer, styrene-methacrylic acid copolymer, styrene-acrylic acid copolymer. Etc., and these can be used as a mixture.
[0014]
Polyolefin resins include high-density polyethylene, medium-density polyethylene, low-density polyethylene, linear low-density polyethylene, linear ultra-low-density polyethylene, polypropylene, polybutene-1, ethylene-propylene block copolymer, ethylene -Propylene random copolymers, ethylene-propylene-butene terpolymers, etc., or graft polymers of these polyolefin resins and polystyrene resins and / or acrylic resins, etc. Can also be used.
[0015]
The polystyrene-based resin and polyolefin-based resin are used without being crosslinked or in a crosslinked state. Among the above-described resins, in the present invention, polyolefin resins are preferable, and among them, non-crosslinked polypropylene resins and non-crosslinked polyethylene resins are preferable.
[0016]
A pair of upper and lower chambers 11, 12, 13, 14, 15 are provided along the passage 9. In the illustrated apparatus, for example, the chambers 13, 14 are used for supplying molding steam. In the method of the present invention, in the first heating region, the foaming particles are heated by supplying molding steam from the lower side to the upper side of the passage 9 or from the upper side to the lower side. In the above example, the space between the chambers 13 and 13 of the passage 9 corresponds to the first heating region. In order to supply the forming steam into the passage 9 from the lower side to the upper side of the passage 9 or from the upper side to the lower side, the forming steam is supplied to either the lower side or the upper side of the chamber 13. The
[0017]
Next, in the second heating region, the forming steam is supplied in a direction opposite to the steam supply direction in the first heating region to heat the expanded particles. That is, when the forming steam is supplied from the lower side to the upper side in the first heating region, the forming steam is supplied from the upper side to the lower side in the second heating region, and the lower side from the upper side in the first heating region. When the forming steam is supplied toward the side, the forming steam is supplied from the lower side to the upper side in the second heating region. In the above example, the space between the chambers 14 and 14 of the passage 9 corresponds to the second heating region. In the second heating region, the forming steam supplied to the lower side or the upper side of the chamber 14 (the side opposite to the side where the steam is supplied in the chamber 13) is jetted into the passage 9 to heat the foamed particles.
[0018]
In the method of the present invention, in the chambers 13 and 14, when the chamber on the side opposite to the side to which the forming steam is supplied is sucked to suck the steam in the passage 9, the foamed particles are efficiently heated. It is preferable because it can be formed by steam.
[0019]
The temperature of the forming steam supplied in the first heating region and the second heating region is slightly different depending on the internal pressure applied to the foamed particles and the bulk density of the foamed particles, but the resin composition constituting the foamed particles shows When the melting point (Mp) is used as a standard, when the expanded particles are usually made of an uncrosslinked polypropylene resin, it is (Mp-15 ° C.) to (Mp + 10 ° C.), and when the expanded particles are made of an uncrosslinked polyethylene resin. , (Mp-10 ° C.) to (Mp + 10 ° C.). The Mp was heated from room temperature to 210 ° C. at a rate of 10 ° C./min by a differential scanning calorimeter, then lowered to 40 ° C. at 10 ° C./min. The temperature at the top of the main melting peak in the second DSC curve obtained when the temperature is raised to 10 ° C. at 10 ° C./min. Further, when sucking the forming steam, the suction side chamber may be connected to a vacuum pump.
[0020]
In carrying out the method of the present invention, the chambers 13 and 14 of the above manufacturing apparatus should be connected to the forming steam supply line only on the side to which the forming steam is supplied (either the lower side or the upper side). Even when suction is performed from the opposite side to the steam supply side as required, only the chamber on the opposite side to the steam supply side needs to be connected to the suction line. However, in the first heating region, in some cases, the forming steam is supplied from the upper side to the lower side, and in some cases, the supply direction of the forming steam is changed depending on the case. When it is necessary (of course, it is necessary to change the steam supply direction in the second heating region in this case), or considering that the chambers 11 to 15 have various functions as described later, all the chambers It is preferable that both the upper side and the lower side of 11 to 15 can be freely connected to the forming steam supply line and the suction line by switching valves or the like.
[0021]
As described above, when both the upper side and the lower side of all the chambers 11 to 15 are configured to be connectable to the forming steam supply line and the suction line, the supply of the forming steam is made to be performed in the chambers 13 and 14. It is not limited to the case where it is used, and it is possible to use the chambers 11 and 12 or the chambers 14 and 15. The first heating region may be configured by combining two chambers, for example, chambers 12 and 13, and the second heating region may be configured by combining two chambers, chambers 14 and 15.
[0022]
In the method of the present invention, it is preferable to suck the steam in the passage 9 on the upstream side (foamed particle supply side) of the first heating region because the foamed particles 6 are stably supplied into the passage 9. As described above, when the forming steam is supplied by the chambers 13 and 14, the steam suction on the upstream side of the first heating region is performed in the chamber 11 or the chamber 12 or in the chambers 11 and 12 at the same time. Also good. Further, if necessary, suction may be performed in the chamber 15 on the downstream side of the second heating region, and if suction is performed on the downstream side of the second heating region, the line speed can be further increased.
[0023]
In the method of the present invention, the foamed particles may be preheated before the foamed particles 6 are transferred to the first heating region. If the foamed particles are preheated and then heat-molded in the first heating region and the second heating region, there is an advantage that a thick foam can be easily obtained. In the above-described example in which the forming steam is supplied by the chambers 13 and 14, the preheating may be performed by either the chambers 11 and 12, or by the steam upstream of the first heating region. When the above suction is used together, it is preferable that steam is sucked in the chamber 11 and preheating is performed in the chamber 12. When preheating is performed, steam is usually supplied to the upper and lower chambers. The steam temperature for preheating is based on the above Mp. Usually, when the expanded particles are made of non-crosslinked polypropylene resin, (Mp-35 ° C.) to (Mp-15 ° C.), no expanded particles are present. When it consists of a crosslinked polyethylene resin, (Mp-20 ° C) to (Mp-10 ° C) are preferred.
[0024]
The molding apparatus for carrying out the present invention may be provided with at least two chambers so that the first heating region and the second heating region can be formed, but as described above, the five chambers are provided. If equipped, suction can be performed on the upstream side of the first heating region and the downstream side of the second heating region as necessary, or the expanded particles can be preheated on the upstream side of the first heating region, Since the manufacturing efficiency of a molded object can be improved more, it is preferable. In order to eject steam into the passage 9 or suck the steam in the passage, the belts 2 and 4 and the thickness regulating plates 7 and 8 need to have steam permeability. For example, a stainless steel belt having a thickness of about 0.2 to 1.0 mm and a plurality of through holes having a diameter of 0.5 to 3.0 mm formed at a pitch of about 3 to 50 mm is used. Steam is supplied into the passage 9 through through holes provided in the thickness regulating plates 7 and 8.
[0025]
The expanded particles used in the method of the present invention preferably have a bulk density of 0.009 to 0.4 g / cm ³ . When the expanded particles are polyolefin resin expanded particles, as described in Japanese Patent Application No. 8-355665 previously proposed by the present inventors, a protrusion 17 is provided in the vicinity of the entrance of the passage 9, and the expanded particles 6 are After compression by the protrusions 17, it is preferable to mold after releasing part or all of the compression. The expanded particles 6 are preferably compressed to a bulk volume of 10 to 60% of the original bulk volume, and particularly preferably compressed to a bulk volume of 15 to 50%. When polyolefin resin foam particles are used as the foam particles, those having a compression recovery rate of 80% or more, particularly 85% or more are preferable.
[0026]
The compression recovery rate of the polyolefin resin expanded particles is obtained from the following formula (1).
[0027]
[Equation 5]
Compression recovery rate (%) = V ₂ / V ₁ × 100 (1)
(Where V ₁ is the original bulk volume of the expanded particles, and V ₂ is the bulk volume of the expanded particles 10 seconds after the compression of the expanded particles to 60% of the original bulk volume and then removing the compression. )
[0028]
When the polyolefin resin expanded particles are non-crosslinked polyethylene resin or non-crosslinked polypropylene resin, the DSC curve obtained by differential scanning calorimetry of the expanded particles has two endothermic peaks (Japanese Examined Patent Publication No. 63-44779, Japanese Examined Patent Publication 7- No. 39501) is preferred. The DSC curve refers to a DSC curve obtained when 0.5 to 4 mg of expanded particles are measured with a differential scanning calorimeter by raising the temperature from room temperature to 210 ° C. at a rate of temperature increase of 10 ° C./min. The base resin is a non-crosslinked polypropylene resin or a non-crosslinked polyethylene resin, and the expanded particles having two endothermic peaks in the DSC curve have surface smoothness and dimensional stability compared to those having no two endothermic peaks. And there exists an effect from which the molded object excellent in mechanical strength is obtained.
[0029]
The foamed particles 6 used in the method of the present invention may be those that have been given an internal pressure equal to or higher than the atmospheric pressure by applying pressure treatment with air or the like, but the foamed particles 6 having an internal pressure substantially equal to the atmospheric pressure are used. You can also In the case of using the expanded particles 6 having an increased internal pressure, those having an internal pressure of 2.5 atm (absolute pressure) or less are preferable. Further, when the foamed particles 6 having an internal pressure substantially equal to the atmospheric pressure are used, the pressure treatment process and the equipment for applying the internal pressure of the particles are unnecessary, and as a result, the cost can be greatly reduced. Although there is no restriction | limiting in particular in the particle weight etc. of the foaming particle to be used, Usually, a thing with an average particle weight of about 0.5-5 mg is used.
[0030]
As described above, the supplied foamed particles are heated by passing through the heating region to fuse the foamed particles with each other, and then cooled by the cooling means 16 to obtain the molded body 10.
[0031]
【Example】
Hereinafter, the present invention will be described in more detail with reference to examples.
Examples 1-5, Comparative Example 1
Foamed particles (Mp 138 ° C.) having a non-crosslinked ethylene-propylene random copolymer (ethylene component 4.1 wt%, MFR 8 g / 10 min) shown in Table 1 as a base resin were molded by the apparatus shown in FIG. . The expanded particles were compressed by protrusions so as to be 40% of the original bulk volume, and part of the compression was released to 80% of the original bulk volume, and then subjected to molding. The apparatus used here has a constant width of 300 mm in the passage from the supply part of the foamed particles to the outlet of the molded body, and 50 mm in the passage from the passage of the protrusion to the molded body outlet of the cooling region (Examples 1 to 3). 4, Comparative Example 1), having a constant height of 80 mm (Example 5). The length from the center of the roll 3b to the protrusion 17 is 1.5 m, the length of the protrusion 17 is 20 cm, the length from the end of the protrusion 17 to the cooling means 16 is 2 m, and the length of the cooling means 16 is 6 m. Met. The conditions such as forming steam supply and suction in each chamber are shown in the chamber pressure column of Table 1. In Table 1, the first to fifth chambers indicate the most upstream chamber 11 to the most downstream chamber 15 in order. The numerical values in the column of the pressure in the chamber of Table 1 indicate the pressure (kg / cm ² · G) of the supplied forming steam and preheating steam as' Vac. 'Indicates that the inside of the chamber was sucked with a vacuum pump. “-” Indicates that neither supply nor suction of the forming steam was performed. Table 2 shows the line speed at the time of molding and the properties of the obtained molded body.
[0032]
In addition, the properties of the molded product were transferred to a curing room under normal pressure set at 60 ° C. and left for the time indicated in the column of “Molded product curing time” in Table 2, and then at room temperature and normal pressure. It was measured, tested or observed after being moved to the room and left for 24 hours. Moreover, a molded object curing time means the minimum time for the molded object volume contracted greatly after shaping | molding to return to the original volume.
[0033]
In all of the obtained molded articles, the voids between the particles were well filled until no voids were observed between the foamed particles, almost no dents were observed on the surface of the molded article, and the fusion between the particles was good. It was.
[0034]
In Example 1 in which the forming steam was supplied into the passage 9 from the lower side of the third chamber 13 and then supplied into the passage 9 from the upper side of the fourth chamber 14, the forming steam was supplied from the upper and lower sides of the third chamber 13. Compared with the comparative example 1 supplied in 9, there is an advantage that the line speed can be increased by 30% or more and the molded body curing time can be halved.
[0035]
Further, in addition to the operation of the first embodiment, the pressure (temperature) of the forming steam is reduced in the second embodiment in which vacuum suction is performed from the upper side of the third chamber 13 and the lower side of the fourth chamber 14 as compared with the first embodiment. Therefore, it is more advantageous than Example 1 in terms of energy cost. Furthermore, in addition to the operation of the second embodiment, in the third embodiment in which vacuum suction is performed from above and below the second chamber 12 located on the upstream side of the third chamber 13, the backflow of the foam particles in the passage 9 is reliably prevented. Even if a long-term operation is performed, a good molded article can be obtained stably.
[0036]
In addition to the operation of the third embodiment, in the fourth embodiment in which vacuum suction is performed from above and below the fifth chamber 15 located on the downstream side of the fourth chamber 14, the line speed can be increased by 25% compared to the first to third embodiments. There are advantages you can do. Further, in addition to the operation of the second embodiment, in the fifth embodiment, vacuum suction is performed from above and below the first chamber 11, preheating steam is supplied from above and below the second chamber 12, and vacuum suction is performed from above and below the fifth chamber 15. There is an advantage that a molded body having a thickness 1.6 times that of Examples 1 to 4 can be obtained.
[0037]
[Table 1]

[0038]
[Table 2]

[0039]
【The invention's effect】
As described above, the method of the present invention supplies the forming steam from the upper side to the lower side or from the lower side to the upper side in the first heating region, and then heats the first steam in the second heating region. By adopting a method in which the forming steam is supplied in the direction opposite to the forming steam supply direction in the heating zone and heated to form, the foaming particles can be formed by the forming steam even when the line speed is increased. A molded body that can be reliably and evenly heated and has excellent fusion property of the expanded particles can be obtained without increasing the pressure of the molding steam. For this reason, when the line speed is increased, there is no problem such as a long time required for curing of the obtained molded body as in the conventional method in which the steam pressure for molding must be increased, and the line speed is increased. In combination with this, an excellent molded body can be obtained efficiently.
[0040]
In the first heating region and the second heating region, if the suction is performed from the side opposite to the side on which the forming steam is supplied, the foamed particles can be heated more efficiently by the forming steam. Furthermore, when the steam in the passage is sucked on the upstream side of the heating region, the foamed particles can be stably supplied, and an excellent molded body can be obtained stably. Furthermore, according to the method of the present invention, it is possible to produce a long molded body that has been difficult with the batch molding method, and the polyolefin resin foam molded body that has been mainly produced by the conventional batch molding method. Productivity can be greatly improved, and automatic molding is also possible, which can greatly reduce costs. In addition, it is possible to continuously and efficiently produce a composite panel in which a synthetic resin film is laminated on the surface of the molded body, and to reduce the cost of the composite panel using the foamed particle molded body as a core material. Have.
[Brief description of the drawings]
FIG. 1 is a schematic view of a molding apparatus used for carrying out the method of the present invention.
[Explanation of symbols]
2, 3 Belt 6 Expanded particle 9 Passage 10 Molded body 11 Chamber 12 Chamber 13 Chamber 14 Chamber 15 Chamber 16 Cooling means

Claims (4)

Foam particles are supplied between belts that are surrounded by a structural material and continuously move along the upper and lower surfaces in a passage having a substantially rectangular cross section. In the method of continuously producing a foamed molded article by sequentially passing, the heating area includes a first heating area and a second heating area on the downstream side thereof, and from the upper side to the lower side of the passage in the first heating area. Alternatively, after supplying and heating the forming steam from the lower side to the upper side, the forming steam is supplied and heated in the second heating region in a direction opposite to the steam supply direction in the first heating region. A method for producing a foamed molded product. The method for producing a foamed molded product according to claim 1, wherein in the first heating region and the second heating region, steam in the passage is sucked from the side opposite to the steam supply side of the passage. The method for producing a foamed molded product according to claim 1 or 2, wherein the inside of the passage is sucked upstream of the first heating region. The method for producing a foamed molded article according to any one of claims 1 to 3, wherein the foamed particles are polyolefin resin foamed particles.

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