JP4566114B2 - Method for producing foam molded article - Google Patents

Description

The present invention relates to an improvement in production how of the foamed molded product obtained by the expandable resin beads filled in a mold and heating and foaming with means such as steam heating.

  Conventionally, foamed resin moldings obtained by filling foamed resin particles such as expanded polystyrene resin into a mold and heating and foaming by means such as steam heating are well known. As for the body, as a result of emphasizing heat insulation and cold insulation and buffering properties as represented by BOX for fresh food storage and transportation such as “fish box”, there is no void inside, and it is substantially non-breathable The material was finished and, for example, did not have a pore structure suitable for a sound absorbing material.

  Therefore, research has been conducted to give an appropriate pore structure of the foamed resin molded body. However, in order to achieve a favorable pore porosity, it is necessary to lower the heating temperature condition, and as a result, the bond strength of the foamed cell As a result, the structural strength practical for the molded body could not be obtained, and the practical application was not successful. In order to improve such a point, the foamed resin molded article of Patent Document 1 has been proposed.

In the foamed resin molded body known from Patent Document 1, a low temperature adhesive resin for heat adhesion is attached to the surface of the foamable resin particles as a raw material, and the foaming amount is adjusted during molding. The foamed cells are bonded and bonded together with the adhesive resin while leaving the pore structure, and the following inconveniences exist for the reason of using the adhesive resin.
1) Material costs and processing costs are increased.
2) The fluidity of the expandable resin particles decreases, the filling device is clogged, and the operability is inferior, such as the degree of filling in the mold is likely to be uneven.
3) Due to the low-temperature softening properties of the adhesive resin, heat resistance and long-term durability are greatly reduced.

  In order to solve the above problems, the applicant of the present invention has proposed a novel foam molded article and a method for producing the same. [Japanese Patent Application No. 2005-37960 (Application 2005 / 02.15), Priority: Japanese Patent Application No. 2004-266853 (Application 2004.09.14)]

The void structure of the foamed molded article having an appropriate structural strength can be obtained by controlling the amount of foaming by decreasing the pressure inside the mold while controlling the fusion resin foaming and cooling. In such a method, even if it is suitable when the conventional polyolefin-based expandable resin particles are used as a raw material, the same heating means as the expandable polystyrene particles or expandable polystyrene particles by increasing the melt tension When molding polyolefin-based expandable resin particles, etc., that can be molded as raw materials, there is a problem that it is difficult to obtain a certain foamed molded product because the quality such as volume porosity and tear strength varies. there were.
Japanese Patent No. 3268094 (Japanese Patent Laid-Open No. 7-168577): claims, paragraphs [0017] [0018] and the like.

The present invention has been made in order to solve the above-described problems, and can be molded without using an adhesive resin, and can be molded with expandable polystyrene particles or heating means similar thereto. Provided is a method for producing a foamed molded product of stable quality, which can achieve both a preferable pore structure and structural strength even in a foamed resin molded product using resin particles as a raw material.

  The present invention is also applicable to foam molding of a foamed molded article composed of a large number of foamed cells obtained by heating and foaming foamable resin particles filled in a mold. This is based on the knowledge found by the present inventor that particles are fused and bonded firmly while providing voids between the particles by introducing high-pressure air.

The above problem is a foamed molded body composed of a large number of foamed cells obtained by heating and foaming the foamable resin particles filled in the mold, and the adjacent foamed cells themselves are joined by a fused portion. And a method for producing a foamed molded article having a three-dimensional continuous air hole formed between the plurality of foamed cells and having a bending limit strength of at least 10 N, the foaming in the presence of heated steam. When the heat-resistant resin particles are heated to the fusing temperature, the supply of heated steam is stopped, control air having a pressure higher than the pressure inside the mold is introduced into the mold, the inside of the mold is pressurized to a higher pressure, and the fusing temperature is reached. A foamed molded article characterized by compressing heated foamed cells so that adjacent foamed cells themselves are joined by a fused portion and three-dimensional continuous air holes are formed between the plurality of foamed cells. According to the manufacturing method It can be solved Te.

  Further, the present invention can be embodied in a form characterized in that the pressure in the mold is pressurized to a value not less than 1.5 times the pressure in the mold when the mold pressure is heated to the fusion temperature by the control air. The temperature of the control air is preferably in the range of the in-mold temperature at the time of introduction to normal temperature. Furthermore, it is preferable to fuse the foamed cells while controlling the pressure by controlling the pressure following the high-pressure heating to control the foaming amount of the foamable resin particles.

According to the foam molded article produced by the present invention , a polystyrene-based foam molded article that can withstand handling and conveyance without using an adhesive resin and has a bending limit strength of 10 N or more as a practical structural strength as a structure. Because it is composed of a body, the cost increase caused by the adhesive resin is suppressed, the original properties of the foamable resin particles can be utilized, and the problems of operability, heat resistance, and long-term durability can be solved Is obtained.
Further, those having a pore structure having a volume porosity of 10 to 40% are automobile interior members, vehicle floor flat materials that flatten the unevenness of the vehicle body floor surface, building sound absorbing members, road / railway noise prevention It is useful as a member, a sound absorbing member for housing, or a sound absorbing member for industrial equipment.

  Further, according to the method for producing a foam molded article of the present invention, the expandable polystyrene resin particles that have reached the fusion temperature in the mold can be fused and bonded after being pressurized with high-pressure control air. In addition, the structure of the three-dimensional continuous air hole can be stably formed, and a polystyrene foam molded article and a polypropylene foam molded article with more stable quality can be produced.

Thus, the method for producing a foamed molded article of the present invention solves the conventionally difficult problem of obtaining a preferable pore structure and structural strength for a sound absorber without using an adhesive resin. There are excellent effects that the cost increase, operability, heat resistance and long-term durability caused by the adhesive resin can be prevented. Therefore, the present invention has an extremely large industrial value as a foamed molded product and a method for producing the same, which have solved the conventional problems.

Next, an embodiment in which the method for producing a foamed molded product of the present invention is performed using expandable polystyrene resin particles as a raw material will be described with reference to FIGS.
(Foamed molded product)
A foamed molded product produced according to the present invention will be outlined with reference to a schematic conceptual diagram 1. First, the foamed molded body is composed of a large number of foamed cells 11, 11,... Obtained by heating and foaming foamable resin particles filled in a mold. The foam-molded body 1 is characterized in that the foam-molded body 1 first contains foamable resin particles that can be foam-molded by a foamable polystyrene resin or other similar means in the mold. It is a foamed resin molded product obtained by filling and heating and foaming by steam heating or the like. In the following description, the foamed molded product means one made of polystyrene resin unless otherwise noted.

  Secondly, in this foamed molded product, the contact surfaces 11a, 11a,... Of the adjacent foam cells 11, 11,... Become fused portions (see FIG. 2B, which will be described later). Are connected to each other and the voids 12, 12,... Between the plurality of foam cells 11, 11,... This is in the formation of pores. That is, since the foamed resin material is fused in the fusion part, which is the joint part, it has exactly the same physical properties as the foamed resin material, and a strong bond can be obtained. The combined state will be described in detail later.

  Next, the strength of the foam of the present invention is required to have a minimum shape retention strength that can withstand handling, and preferably has a mechanical strength as a structure. From this point, the bending limit strength is adopted as a measure representative of mechanical strength, and it is characterized by having a strength of at least 10N, and more preferably 22N or more.

  The three-dimensional continuous air hole in the foamed molded article of the present invention has a complicated spatial path in which a large number of branches and zigzags and bends, and the inner diameter repeats the change of expansion and contraction irregularly. On the other hand, it exhibits the basic sound absorbing function of attenuating effects such as reflection, interference and resonance. Further, it goes without saying that the basic structure exhibits a preferable mechanical buffering function of the foamed molded product. In addition, it is preferable that the volume porosity which is the total volume ratio of the fine pores with respect to the whole volume is 10 to 40% in the three-dimensional continuous air holes.

  When this volume porosity is less than 10%, it is convenient to obtain high strength, but it is not preferable as a sound absorber because the sound absorbing effect is insufficient. On the other hand, if it exceeds 40%, the sound absorption effect tends to decrease, and the mechanical strength is difficult to obtain, which is not preferable.

The shape of the foam cell constituting the foam molded article of the present invention also has the following characteristics. That is, the cut cross section of the foam cell is a granule having a substantially circular or oval cross section, and the size thereof is preferably 1.5 to 5.5 mm on the basis of the major axis. If it is outside this range, it is difficult to obtain a fine pore volume that is preferable for the sound absorbing action.
In addition, it is preferable that each foam cell has a substantially oval cross-sectional particle having a major axis / minor axis range of up to 3.0, because a fine pore volume necessary for sound absorption is easily obtained.

Next, the combined state of the foamed cells of the present invention will be supplemented with reference to FIG. FIG. 2 is a schematic diagram showing typical bonded states A, B, and C of the foam cells in the foam molded article of the present invention.
First, the figure (A) is what the foaming cells 11 and 11 couple | bonded together in the pressing state, and the melt | fusion part 2a is formed along the boundary. In this case, although a relatively strong bond strength can be obtained as compared with the cases (B) and (C) described later, the sound absorption is somewhat inferior because the porosity is small.

  The figure (B) is an intermediate form of the figure (A) and (C), Comprising: The foaming cells 11 and 11 maintain a contact state, The fusion | melting part 2b is formed in the meantime. Such a state is formed by compressing the foamed cell from the state of FIG. (A) by external pressurization at the time of fusion. Specifically, it will be described in detail in the manufacturing method of the second invention. .

  FIG. (C) shows a form in which the foamed cells 11, 11 joined by the fusion part 2 c have a separated positional relationship, and the fusion part 2 c is formed in a cross-linked state spanned between them. ing. Such a state is formed by further compression from the state of FIG. (B) by external pressurization, but in this combined state, the two previous types (A) are maintained while maintaining sufficient strength. Since a larger porosity can be obtained than in the case of (B), it can be said to be a more preferable embodiment.

Next, the present invention will be supplemented from the application aspect.
The foamed molded article produced according to the present invention is suitable not only as a sound absorbing material but also as a structural member that bears strength, and is therefore suitable for an automotive interior member that requires moderate sound absorbing properties and strength. For example, it can be used for dashboard surface members, vehicle interior wall materials, floor members, and the like. In these cases, the surface layer portion having a small or substantially zero volume porosity is preferably integrally molded on one side (surface side) so as to be 10 to 45% of the total thickness of the foamed molded product.

  Further, when used as a floor material, the surface layer portion is arranged facing the vehicle compartment side, and a foamed molded product is interposed between the surface of the vehicle body floor and the unevenness of the vehicle body floor surface is flattened by the foamed molded product. It is preferably used as a vehicle floor flat material.

  Furthermore, it goes without saying that the present invention can be widely used as a sound absorbing interior member such as a building wall or a ceiling, a road / railway noise preventing member, a residential sound absorbing member, or an industrial equipment sound absorbing member. In this case, the surface layer portion constitutes a decorative face having strength, and the thickness is 10 to 45% of the total thickness, and a range of 1 to 40 mm is appropriate.

(Method for producing foamed molded article)
The manufacturing method of the foaming molding of this invention is demonstrated with reference to FIGS. The present invention is a method for producing a foamed molded article as described above, and when the foamable resin particles are heated to a fusion temperature in the presence of heated steam, control air having a pressure higher than the pressure inside the mold is placed in the mold. An important requirement is to introduce and pressurize the mold to a higher pressure.

  Here, FIG. 3 shows the important operating conditions in the foam molding method of the present invention, that is, the pressure (pressure curve 4) and temperature (temperature curve 4a) in the mold filled with expandable resin particles on the vertical axis. FIG. 4 is a graph schematically showing the behavior slightly exaggerated on the horizontal axis, and FIG. 4 is a similar graph disclosed in Japanese Patent Application No. 2005-37960 filed by the applicant of the present invention. (Pressure curve 5, temperature curve 5a).

  In the method of the present invention, a conventional mold for foam molding which is a combination of a concave mold and a convex mold can be used. The basic point is that a foamed molded product is produced by heating and foaming expandable polystyrene resin particles filled in these predetermined molds (the molding space between concave and convex molds, also called cavities). There is no difference from traditional methods. That is, with reference to FIG. 3, the following B1) temperature rising process, B2) fusing temperature heating process, B3) foaming fusing process, B4) cooling process, B5) air cooling / removal process are roughly divided. Is done.

  B1) Temperature raising step: In the step of heating and raising the temperature inside the cavity, the inside of the cavity is filled with foamed resin particles, followed by exhaust in the chamber, one-way exhaust heating with heated steam in the cavity, and reverse exhaust heating in the same way. Heat up with steam and fill with steam. The pressure curve 4 and the temperature curve 4a actually rise while zigzag.

  B2) Fusion temperature heating step: Foamed resin particles are foamed (expanded) and fused to form a predetermined shape along the cavity shape. Heating to temperature. In the latter half of this process, the expanded polystyrene resin particles are heated at a vapor pressure corresponding to the fusing temperature, so that the fusing temperature reaches a fusing temperature, and the foaming pressure of the foaming component rises rapidly. Then, a number of adjacent particles are brought into contact with each other from the flowable state so far, and fusion starts at the contact portion and reaches a state where the particles are in progress.

B3) Foam fusion process: a process characterized by the present invention. Following the B2 process, the process of completing foam cell fusion while controlling the amount of foaming (expansion) of the expandable resin particles and forming voids. However, in the case of the prior application (FIG. 4), the important point is that the pressure curve 5 is gradually decreased from the point a to the point c by adjusting the supply and exhaust of the steam, while the present invention. In FIG. 3, the inside of the mold has a uniform set fusing temperature, and the control air is introduced at point a where fusing has started to increase the pressure inside the mold to a higher point A.
In FIG. 3, after this pressurizing operation, the pressure is reduced while controlling to the control end pressure B point. This control end pressure B point is a pressure corresponding to a point b whose temperature is the fusion completion temperature.

  The purpose of the high-pressure pressurization with the control air of the present invention is that the polystyrene foamable resin particles that have reached the fusion temperature are extremely unstable in the foaming internal pressure. In other words, it is possible to prevent the occurrence of a sudden fusion phenomenon, that is, a fusion state that fills the voids. Then, by controlling the pressure, the internal pressure of the particles (particle internal pressure) and the external pressure (cavity internal pressure) are balanced, while leaving a void (volume porosity) between the expandable resin particles, A landing part can be formed.

For this purpose, it is necessary to use air instead of steam. This is because, compared with steam, air is less likely to enter the inside of the foamed particles, so that it is easy to control the external pressure on the particles.
In addition, as the control air for this purpose, it is important to set the temperature and pressure appropriately. The control air introduced in the present invention is pressurized air having a pressure capable of pressurizing 1.5 times or more, preferably 2 times or more of the pressure in the mold when the mold pressure is heated to the fusion temperature. Is optimal. Moreover, it is preferable that the temperature of the control air is a temperature in the range between the in-mold temperature at the time of introduction and normal temperature.

  The reason why the condition of the control air is preferable is that when the pressure is less than 1.5 times, the above-mentioned sudden fusion phenomenon cannot be sufficiently prevented, and partial unevenness occurs in the three-dimensional continuous air hole. Further, when the pressure is more than 3 times, the prevention effect cannot be expected beyond that. In addition, when the temperature is outside the above-described range, unevenness in the fused state of the foamed molded product tends to occur, and it is difficult to obtain a homogeneous foamed molded product.

  In general, if the decompression speed is increased, the expansion is promoted and the volume porosity is decreased, and if the decompression speed is decreased, the expansion is suppressed and the volume porosity is increased. Since the foaming characteristics of the resin vary depending on the type of resin and the prefoaming treatment, the degree of decompression speed, the decompression curve, and the value of the control end pressure are determined by conducting a preliminary test based on the foamable resin particles used in advance. . Here, the fusion completion temperature is a temperature at which the fusion phenomenon does not proceed.

  The fusing temperature and fusing completion temperature are values determined mainly by the resin type of the expandable resin particles to be used. For example, in the case of the polystyrene resin of the present invention, the lower fusing temperature is 90 to 100 ° C. The upper limit is preferably up to 105 ° C. The fusion completion temperature is 110 to 120 ° C. Accordingly, the set fusion temperature at point a is set between the upper limit and the lower limit fusion temperature.

B4) Cooling step B4: Cooling is performed by pouring cold water into the chamber while maintaining the pressure pressurized by the control air.
B5) Air cooling / releasing step: Thereafter, the exhaust valve of the chamber is opened, the gas inside is exhausted, the mold is opened, and the molded body is taken out.
Thus, the three-dimensional communication having a volume porosity of preferably 10 to 40%, in which the foamed molded product according to the first invention of the present invention, that is, the adjacent foamed cells themselves are joined together by a softened and melted fused portion. A polystyrene foam molded article having pores and a bending limit strength of at least 10 N is obtained.

(Example 1) Next, examples of the production method of the present invention and characteristics of the foamed molded product obtained thereby will be described with reference to Table 1.
The specifications of the manufacturing conditions are as follows. FIG. 5 shows changes in product internal temperature 6a, mold temperature (average) 6c, and in-mold pressure 6 during the molding process.
a) Used foamed resin: Type = polystyrene resin, particle size = 2.5 to 3.5 mm, preliminary foaming treatment = completed.
b) Mold: A normal heating type open / close mold using heated steam provided with vent holes on both sides of the cavity.

c) Temperature raising step B1: up to the fusion temperature heating step
The filling of the foamed resin particles, the exhaust in the chamber, the one-way exhaust by the heating steam in the cavity, and the reverse exhaust in the same manner are performed under the conditions conventionally known.
d) Fusion temperature heating step B2:
Heated steam of 0.05 to 0.1 MPa is introduced into the chambers on both sides for about 3 seconds, and the foamed resin particles in the cavity are heated to the set fusion temperature (110 ° C.).

e) Foaming / fusion process B3:
The supply of water vapor is stopped at the point a after the end of heating, the control air is supplied for about 3 seconds, and the inside of the mold is pressurized to the pressure shown in Table 1 of the pressurizing pressure. At this time, the product internal temperature that has reached the fusion temperature is further increased by the water vapor trapped inside the product (6a1), the foamed cells are fused to each other to form a fusion part, By being compressed, the fused portion is formed in a crosslinked state. The pressure inside the mold is preferably increased to a predetermined pressure with the control air for a short time, preferably within 5 seconds.

Immediately before the introduction of control air, it is important that the internal temperature of the product has reached the fusion temperature. In this state, air having a pressure higher than the saturation pressure at that time is introduced, and the pressure in the mold is set as described above. Thus, when the pressure is increased to a high pressure, there is a temporary rise in the internal temperature of the product, which is considered to be caused by instantaneous compression of water vapor in the foam cells and between the cells. This increase in temperature seems to promote fusion between cells.
At the same time, the high control pressure (0.1 to 0.2 MPa) acts to hold down the fused foam cell having an increasing foam pressure (0.1 to 0.12 MPa) with increasing temperature. A fused portion in a cross-linked state is formed between them.

f) Cooling step B4:
Cooling water is poured into the chamber while the pressure pressurized by the control air is maintained.
g) Air cooling / release process B5:
Thereafter, the exhaust valve of the chamber is opened, the gas inside is exhausted, the mold is opened, and the molded body is taken out.

  The foamed molded product thus obtained had the physical properties shown in Table 1. In the example sample, a foamed molded article having a strength combined with the three-dimensional continuous air hole was obtained. When the pressure A was low, the amount of air flow was small and varied in sample 1, but 1.5 times or more. In the case of (2), it can be seen that the variation due to the site is small, and when it is twice or more, there is almost no variation, and preferable quality such as porosity, strength and sound absorption can be obtained. In addition, Comparative Example 11 is a molded body obtained by a conventional molding method in which pressurization of the control air of the present invention is not performed, and is excellent in strength but does not provide the pore structure intended by the present invention. .

  In addition, it was confirmed that the example sample has strength that can be used as a structural member as well as handling. Further, as a result of observing the cut cross section, it was confirmed that the foam cells adjacent to each other were softened and melted and bonded at the contact surface. In particular, in the case of Samples 2, 3, and 4, as shown in FIG. 2C, the foamed cells 11 and 11 joined by the fusion part 2c have a separated positional relationship, and the fusion part 2c. Was clearly observed in a cross-linked state between the two.

The air flow rate is the average air flow rate (l) per minute when 30 l of air is discharged from the tip 2.5 cm ² for 5 sample surfaces facing the convex and concave surfaces of the mold. Shows variation.
The average volume porosity is such that the gap space in a single bead state before fusion is 100% porosity. For example, when foam beads are placed in a 1 L graduated cylinder, the gap is filled as a method for obtaining the volume of the space. A value V converted by volume from the weight W (1 cc = 1 g) of the water injected is the 100% porosity of the beads 1000 cc. From the above, for example, the volume (water weight) x with a porosity of 100% when a porous sample is cut to a constant volume v is obtained by v / 1000 = x / W (W = V).
Therefore, the trace of the molded sample actually immersed in water and infiltrated into the inside, the weight w is measured, and the porosity of the sample is obtained as w / x from the comparison between this value and the 100% volume (water weight) x. . Therefore, the average volume porosity is an average value of the porosity of the n samples.
The bending limit strength is measured by a method defined in JIS-K7221.
For sound absorption, a normal incidence sound absorption rate measuring device is used, and the sample is 15 mm thick, when the sound absorption rate is 30% or more in the frequency region measurement (JIS (A) 1405) of 50 to 1600 Hz. Is indicated as x.

(Example 2)
Next, another embodiment of the manufacturing method of the present invention will be described.
The implementation conditions in this case are the same as in Example 1 except for the following parts. FIG. 6 shows changes in the mold temperature 6a, mold temperature (average) 6c, and mold pressure 6 during the molding process.

  In Example 2, the control air introduction step B31 is inserted at the end of the temperature raising step B1 in the chamber exhaust, the one-way exhaust by the heated steam in the cavity, and the reverse exhaust in the same way. There is a fusion temperature heating step B2 in which the foamed resin particles in the cavity are heated to the set fusion temperature. Subsequently, a foaming and fusing step B32 performed by introducing control air is performed, and then cold water is poured into the chamber and cooled while maintaining the pressure pressurized by the control air. In some cases, the cooling release process B5 is performed such as opening the exhaust valve of the chamber, exhausting the gas to the outside, and cooling and releasing in the atmospheric state.

  In this case, a process for introducing control air before and after the fusion temperature heating process B2 is provided. However, the former control air introduction process B31 is partially fused at the end point a1 of the temperature raising process B1. In order to prevent the foamed particles that have reached the temperature from fusing and preventing the pore structure from varying, the control air is introduced to pressurize to the pressure A1, compress the foamed particles, and cool and fuse them slightly. This is an operation to suppress this.

And, similarly to Example 1, at the end point a2 of the subsequent fusing temperature heating step B2, the process proceeds to the foaming / fusing step B32 in which control air is introduced and the pressure A2 is increased, In addition, while maintaining the internal pressure (particle internal pressure) and the external pressure (cavity internal pressure) of the particles, a void portion (volume porosity) is left between the foamable resin particles, and a fusion part is formed on the contact surface. .
Thus, a foamed molded article having the same physical properties as in Example 1 can be obtained. However, as control air, air having a lower pressure than that in Example 1 can be used, which is advantageous in this respect.

Thus, the foamed molded product produced according to the present invention has a sound absorbing effect by such a three-dimensional continuous air hole structure and a sound absorbing material for noise prevention utilizing the original material strength, heat resistance and durability of the foamed resin, for example, It has been confirmed that it is widely useful for automobile interior members, vehicle floor flat materials, sound absorbing materials for buildings such as residential walls, industrial equipment, road noise prevention, and exhaust silencers for factories and subways.

  In addition, although all the above-mentioned explanation is a case where it was performed by using as a raw material the expandable polystyrene resin particle which was the most effective in the experiment, if it can be obtained by heating and foaming the expandable resin particle filled in the mold It can also be applied to the case where all expandable resin particles are used as raw materials. Recently, other than expandable polystyrene resin particles, the molecular weight distribution is expanded, a small amount of ultra-high molecular weight components are added, electron beam irradiation, and kneading. As a result of the development of partial flowering, long chain branching, and graft component addition by modification and catalyst improvement, high melt tension foaming has become possible by the same method as expandable polystyrene resin particles. Polypropylene resin particles (for example, trade name Eperan PP sold by Kaneka Corporation, trade name P-Block released by JSP Corporation) and expandable polyethylene resin Child (for example, trade name PIOCELAN Sekisui Plastics Co., Ltd. has released) it goes without saying that you can also achieve the intended purpose as other raw materials such as foam resin particles of polyolefin.

The typical conceptual sectional view of the foaming fabrication object manufactured by the present invention. Typical conceptual sectional drawing (A) (B) (C) for demonstrating the coupling | bonding state of a foam cell. The typical progress graph which shows the relationship between the pressure in a type | mold in the manufacturing method of this invention, the same temperature, and time. The reference typical progress graph which shows the relation between the pressure in a mold in the manufacturing method of a prior application, the same temperature, and time. The progress graph which shows one example of the relationship between mold pressure, the same temperature, mold temperature, and time in Example 1 of this invention. The progress graph which shows one example of the relationship between mold pressure, the same temperature, mold temperature, and time in Example 2 of this invention.

1 Foam molded body 11 Foam cell
11a Contact surface
12 Gap 2a Fusion part 2b Fusion part 2c Fusion part

Claims (4)

A foamed molded article composed of a large number of foamed cells obtained by heating and foaming foamable resin particles filled in a mold, wherein the adjacent foamed cells themselves are joined by a fused part, A method for producing a foamed molded article having a three-dimensional continuous pore formed between a large number of foamed cells and having a bending limit strength of at least 10 N, wherein the foamable resin particles are melted in the presence of heated steam. When heated to the deposition temperature, supply of heated steam is stopped, control air higher than the pressure inside the mold is introduced into the mold, the inside of the mold is pressurized to a higher pressure, and the foamed cell is heated to the fusion temperature In which the adjacent foam cells themselves are joined by a fused portion, and three-dimensional continuous air holes are formed between the plurality of foam cells. 2. The method for producing a foam molded article according to claim 1, wherein the pressure is increased to 1.5 times or more of the pressure in the mold when the inside of the mold is heated to the fusion temperature by the control air. The method for producing a foamed molded article according to claim 5 or 2, wherein the temperature of the control air introduced is a temperature in the range from the in-mold temperature at the time of introduction to room temperature. The method for producing a foamed molded article according to claim 1, 2 or 3, wherein the foamed cell is fused while controlling the foaming amount of the expandable resin particles by controlling the pressure following the high-pressure heating.

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