JP2012011640A - Container molded from foamed polystyrene resin laminated sheet, method for molding the container, and foamed polystyrene resin laminated sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a container which is excellent in impact resistance and resistant to breakage by impact such as falling even when used in a cold district etc., a method for molding the container, and a foamed polystyrene resin laminated sheet used for molding the container.SOLUTION: In the container, the foamed polystyrene resin laminated sheet in which a polystyrene resin film is laminated on one side of a foamed polystyrene resin film formed by using a polystyrene resin composition containing a polystyrene resin and a polyphenylene ether resin in a ratio of 10 pts.mass or above and 50 pts.mass or below of the polyphenylene ether resin to the 100 pts.mass of the total of the polystyrene resin and the polyphenylene ether resin is molded so that the polystyrene resin film is the inside of the container. A side wall part is formed so that 50% impact destruction energy is 0.5 J or below when impact is applied under the condition of -10°C from a side on which the polystyrene resin film is laminated.

Description

  The present invention relates to a container formed from a polystyrene-based resin laminated foam sheet, a method for forming the container, and a polystyrene-based resin laminated foam sheet.

  A container for reconstitution of instant food such as instant fried noodles is a styrene resin laminated foam sheet in which a styrene film is laminated on a styrene resin foam sheet so that the styrene film is on the inside. Conventionally, with regard to this type of container, so-called piercing strength has been regarded as important because there is a concern that the container may be pierced and destroyed with chopsticks or a fork during cooking or eating. In order to improve the puncture strength, as is also done in Patent Document 1 below, it is generally performed to impart impact resistance by adding a rubber component to the base resin of the film to be laminated.

Japanese Patent Publication No. 63-20702

  However, as described above, for instant food containers such as fried noodles, quality improvement has been made with an emphasis on the impact resistance of the film, but the impact resistance of the entire container is not considered at all. There was nothing. Therefore, the polystyrene resin foam sheet used for the polystyrene resin laminated foam sheet molded into the container has been pursued only for its low price and easy molding. As a result, the impact resistance of the entire container is low, and there is a case where the container breaks particularly when used in cold regions. If a container breaks, of course, when refilling the filled food, the hot water will come off and not only perform the functions of the container, but if it worsens, consumers may be burned. There is. Moreover, since the airtightness is also impaired, there is a problem that the deterioration of the food easily proceeds.

  Accordingly, the present invention provides a container that is excellent in impact resistance and is not easily broken by an impact such as dropping even when used in a cold region, a molding method thereof, and a polystyrene-based resin laminated foam sheet used for molding such a container. The task is to do.

  The inventor is in a state where the polystyrene resin laminated foam sheet is molded so that the polystyrene resin film is on the inside, and is actually sold in a retail store or the like, that is, in a state where the contents are filled and sealed. Then, the container was dropped, or a heavy object was dropped on the container. As a result, the container showed the same breaking condition as when the impact was applied to the side wall portion from the inside, and it was found that the breaking occurred from the outside surface where the polystyrene resin film was not laminated. Furthermore, it is effective to impart flexibility to the polystyrene-based resin foam sheet, and the heating conditions when molding the polystyrene-based resin laminate foam sheet into a container also have an effect on such a fracture mode. The present invention has been found.

That is, the container according to the present invention contains a polystyrene resin and a polyphenylene ether resin, and 10 parts by mass of the polyphenylene ether resin with respect to a total of 100 parts by mass of the polystyrene resin and the polyphenylene ether resin. A polystyrene resin laminated foam sheet in which a polystyrene resin film is laminated on one side of a polystyrene resin foam sheet formed using a polystyrene resin composition contained in a proportion of 50 parts by mass or less is the polystyrene series. The container is formed so that the resin film is on the inside of the container, and the side wall portion has a 50% impact fracture energy of 0% when an impact is applied at −10 ° C. from the side where the polystyrene resin film is laminated. A container characterized by being formed so as to be 5 J or more.
The “50% impact fracture energy” is intended to be a value determined based on JIS K7211.

  Further, the container according to the present invention is molded in a state where the polystyrene-based resin laminated foam sheet is heat-treated and subjected to secondary foaming, and the surface on which the polystyrene-based resin film is laminated is at a temperature of 100 ° C. or higher. It is preferred that

The container according to the present invention has a thickness of 70 to 1 on one side of the polystyrene-based resin foam sheet having a cell number in the thickness direction of 9 to 25 cells / mm and a density of 0.08 to 0.15 g / cm ^3. A polystyrene-based resin-laminated foam sheet having a density of 0.20 g / cm ³ or more in a 150 μm portion in the thickness direction from the surface on which the polystyrene-based resin film is not stacked is laminated with 200 μm of the polystyrene-based resin film. It is preferable that it is molded using.

The polystyrene-based resin laminated foam sheet according to the present invention contains a polystyrene-based resin and a polyphenylene ether-based resin, and the polyphenylene ether-based resin is included with respect to 100 parts by mass in total of the polystyrene-based resin and the polyphenylene ether-based resin. It is formed using a polystyrene-based resin composition contained in a proportion of 10 to 50 parts by mass, the number of cells in the thickness direction is 9 to 25 cells / mm, and the density is 0.08 to 0.15 g / A polystyrene resin laminated foam sheet in which a polystyrene resin film having a thickness of 70 to 200 μm is laminated on one side of a polystyrene resin foam sheet of cm ³ , and the surface on the side where the polystyrene resin film is not laminated the density of 150μm portion of the thickness direction is 0.20 g / cm ³ or more from And butterflies.

  The container manufacturing method according to the present invention includes a polystyrene-based resin and a polyphenylene ether-based resin, and 10 mass of the polyphenylene ether-based resin with respect to a total of 100 parts by mass of the polystyrene-based resin and the polyphenylene ether-based resin. A polystyrene resin laminated foam sheet in which a polystyrene resin film is laminated on one side of a polystyrene resin foam sheet formed using a polystyrene resin composition contained in a proportion of not less than 50 parts by mass and not more than 50 parts by mass. A method for forming a container in which a resin-based resin film is formed inside the container, wherein the polystyrene-based resin-laminated foam sheet is subjected to heat treatment for secondary foaming, and the surface on the side on which the polystyrene-based resin film is laminated is 100. Perform the molding at a temperature of ℃ or higher Therefore, the container is formed such that the 50% impact fracture energy measured by applying an impact at −10 ° C. from the side on which the polystyrene resin film is laminated is 0.5 J or more at least in the side wall portion of the container. It is characterized by making it.

  As described above, according to the present invention, it is possible to provide a container that is excellent in impact resistance and is not easily broken by an impact such as dropping even when used in a cold region.

  The container in the present invention is a polystyrene resin laminated foam sheet (hereinafter referred to as a laminated foam sheet) in which a polystyrene resin film (hereinafter also referred to as a film) is laminated on one surface of a polystyrene resin foam sheet (hereinafter also referred to as a foam sheet). The laminated foam sheet is obtained by thermoforming the film so that the film is inside the container. Such a container has sufficient strength against impact when it is dropped in a sealed place filled with contents or a heavy object is dropped on the container even in a cold place such as a cold region. Have. In order to prevent the container from cracking, the 50% impact fracture energy is 0 when an impact is applied to the side of the side wall portion on which the film is laminated (hereinafter referred to as the film lamination surface) at −10 ° C. .5J or more is necessary. If the 50% impact fracture energy when impact is applied from the film lamination surface side is less than 0.5 J, the container tends to be cracked due to insufficient impact resistance.

The foamed sheet of the present invention is formed using a polystyrene resin composition containing a polystyrene resin and a polyphenylene ether resin. Polystyrene resins include styrene monomer homopolymer resins, random and block copolymer resins with monomers copolymerizable with styrene, mixed resins of these resins, and resins such as polyphenylene oxide that can be mixed with these resins. Examples thereof include mixed resins.
In addition, as said polystyrene resin, the polystyrene resin which is a styrene homopolymer is suitable also from a compatible viewpoint with a polyphenylene ether-type resin.

Further, the polyphenylene ether resin in the present invention is effective for imparting heat resistance, and is 10 parts by mass or more and 50 parts by mass or less with respect to 100 parts by mass in total of the polystyrene resin and the polyphenylene ether resin. Contained in proportions.
In addition, polyphenylene ether-type resin is normally represented by the following general formula.

Here, R ¹ and R ² represent an alkyl group having 1 to 4 carbon atoms or a halogen atom, and n is a positive integer representing the degree of polymerization.
For example, poly (2,6-dimethylphenylene-1,4-ether), poly (2,6-diethylphenylene-1,4-ether), poly (2,6-dichlorophenylene-1,4-ether) Ether) or the like may be used in this embodiment.
The degree of polymerization n is usually in the range of 10 to 5000.

Such a polyphenylene ether resin is effective for improving heat resistance, but the polyphenylene ether resin is used in an amount of 10 parts by mass or more and 50 parts by mass or more with respect to 100 parts by mass in total of the polystyrene resin and the polyphenylene ether resin. It is preferable to contain it in a proportion of less than or equal to parts by mass. If the amount is less than the above range, the addition effect of the polyphenylene ether resin may not be sufficiently exerted, and conversely, the polyphenylene ether resin is contained beyond the above range. This is because there is a possibility that the effect of adding the polyphenylene ether resin will not be exhibited even if it is made to be.
Moreover, since it is generally more expensive than a polystyrene resin, if the polyphenylene ether resin is contained beyond the above range, there is a possibility of causing a problem in terms of material cost.

  Usually, the Vicat softening temperature of polystyrene resin (JIS K7206-1991, Method B, 50 ° C./h) is about 102 ° C., but by including the polyphenylene ether resin as described above, the Vicat softening temperature is reduced. It can be improved to a range of 110 to 155 ° C., and by using a polystyrene resin composition containing the polyphenylene ether resin, the resulting polystyrene resin foam sheet and the polystyrene resin foam sheet are subjected to secondary processing. It is possible to improve the heat resistance of manufactured products.

In general, when heat resistance is required for a product in which a polystyrene resin composition is used, a styrene-methacrylic acid copolymer, styrene-maleic anhydride copolymer, styrene having a higher Vicat softening temperature than a styrene homopolymer -Copolymers such as maleimide copolymer and polyparamethylstyrene resin are employed as the forming material.
On the other hand, the method of blending the polyphenylene ether-based resin as described above is excellent not only in imparting heat resistance to the product but also in imparting excellent toughness.

  Therefore, when a foamed tray or the like is formed using a polystyrene resin composition containing a polyphenylene ether resin, it is possible to form a foamed tray that does not crack even if sudden deformation is applied.

However, since the polyphenylene ether-based resin has a peculiar odor, it is preferable to contain a component for deodorization particularly in applications where odor is hated.
Examples of the deodorant component include zeolite-based and zirconium phosphate-based inorganic particles.
Especially, it is preferable to employ | adopt a zirconium phosphate type component in the point of the deodorizing effect.

  And after adding inorganic substances such as talc and calcium carbonate to these resins as a nucleating agent, they are melt-mixed together with a physical foaming agent such as propane, butane and pentane and a chemical foaming agent such as sodium bicarbonate-citric acid in an extruder. Thereafter, the foamed sheet is obtained by extrusion foaming from a circular die or the like. At this time, the number of cells in the thickness direction of the foamed sheet can be adjusted depending on the type of nucleating agent and the amount added. Moreover, the density of a foam sheet can be adjusted by adjusting the mixing amount of a foaming agent and the lip opening degree of the circular die which extrudes resin. Furthermore, cell formation on the surface of the foam sheet during extrusion foaming involves adjusting the resin temperature during extrusion from the die, the die lip gap, etc., selecting the foaming agent, and air on the surface of the foam sheet immediately after exiting the die. It can be adjusted by the operation when spraying and quenching.

Here, in order to obtain a molded container having excellent impact resistance, it is important that the foamed sheet has sufficient strength and flexibility. For that purpose, the number of cells in the thickness direction of the foamed sheet is preferably 9 to 25 cells / mm, and the density is preferably 0.08 to 0.15 g / cm ³ . When the number of cells in the thickness direction is less than 9 cells / mm, or when the density exceeds 0.15 g / cm ³ , the cell membrane becomes too thick and the foam sheet becomes inflexible. For this reason, although it is high in strength, it becomes a fragile container. Also. When the number of cells in the thickness direction exceeds 25 cells / mm, or when the density is less than 0.08 g / cm ³ , the cell film becomes thin, so that a good molded body can be obtained without stretching the sheet during molding. There is no strength.
In addition, the thickness of a foam sheet is 1.0 mm-3.0 mm normally.

Furthermore, the density of the 150 μm portion in the thickness direction from the surface opposite to the surface on which the film is laminated in the subsequent step is preferably 0.20 g / cm ³ or more. When the density of the surface layer is 0.20 g / cm ³ or more, fine cells having a major axis of 50 μm or less are generated by heating during molding, and the impact resistance of the container is improved. This is because the fine cells generated on the surface disperse and absorb the impact applied to the container. On the other hand, if the density of the surface layer is less than 0.20 g / cm ³ , sufficient fine cells are not generated by heating during molding, and sufficient impact resistance cannot be imparted to the container. Further, the density of the surface layer portion is about 0.60 g / cm ³ . If an attempt is made to increase the density of the surface layer beyond this, it is necessary to increase the sheet cooling during extrusion, and the stability of foaming may be impaired.

  After curing for 2 to 8 weeks, a polystyrene resin film extruded from a T-die is laminated on the obtained foamed sheet by an extrusion lamination method. The film is a non-foamed film, and the polystyrene-based resin used is the same as that used for the foamed sheet. The same resin as the foamed sheet may be used, or a different resin may be used. You may do it.

  From the viewpoint of impact resistance, the Izod impact strength of the resin used for the film is desirably 80 J / m or more. When the Izod impact strength is less than 80 J / m, the laminated film is easily broken, and when the container is taken out from the mold after thermoforming, the cut end is cracked, or the filled noodles or chopsticks pierce the container. Problems such as opening a hole may occur. In order to obtain an Izod impact strength of 80 J / m or more, it is desirable to use a base resin of the film in which a rubber component such as SBS is added to an impact-resistant polystyrene resin or a polystyrene-based resin. 4% or more is desirable.

  Furthermore, the thickness of the film is preferably 70 to 200 μm. If the film is thinner than 70 μm, the inner surface of the container is easily scratched by noodles or chopsticks even if a base resin having excellent impact resistance is used as described above, and a thickness exceeding 200 μm is not economically preferable.

  The polystyrene-based resin laminated foam sheet thus obtained is set in a molding machine so that the inside of the container becomes a film lamination surface, and heated in a heating furnace equipped with an infrared heater or the like to be secondarily foamed, The container is formed into a container shape using a mold (such as a pair of molds). Under the present circumstances, it is preferable to heat so that the thickness of a laminated foam sheet may be 80% or more of the maximum secondary foaming thickness (in other words, secondary foaming and thickness will be 2 times or more). The maximum secondary foam thickness is the maximum thickness that can be developed when the laminated foam sheet is subjected to secondary foaming under different heating conditions. If the secondary foaming thickness is less than 80% of the maximum secondary foaming thickness, the above-mentioned fine cells do not occur on the outer surface of the container, and sufficient impact resistance may not be imparted to the container. In addition, the laminated foam sheet may not be sufficiently stretched due to insufficient heating, and the resulting container may not be imparted with a shape according to the molding die, and in some cases, a crack or crack may occur in the container.

  Furthermore, in order to obtain a container having excellent impact resistance, the laminated foamed sheet is sufficiently heated in a heating furnace so that the temperature of the film laminated surface immediately before being molded with the mold is 100 ° C. or higher. It is desirable to mold in a temperature state. When the temperature of the film lamination surface is less than 100 ° C. and the heating is insufficient, the film is not sufficiently softened, the film on the side wall portion is excessively stretched during molding, and the film is easily broken. In addition, if the thickness is 80% or more of the maximum secondary foam thickness in this state, the heating of the film non-laminate surface becomes excessive, the stretch between the foam sheet and the film is uneven, and the moldability is impaired, The secondary foaming ratio on the non-laminate surface of the film becomes too high, and the cell film on the surface layer becomes thin, resulting in reduced impact resistance.

  The temperature of the film lamination surface immediately before being molded with the molding die is more preferably 105 ° C. or higher, and most preferably 110 ° C. or higher. Moreover, the upper limit of the temperature of a film laminated surface should just exist in the range which can shape | mold a molded article with a favorable external appearance, and when a laminated foam sheet is used with a general molding machine, it is 160 degrees C or less.

  EXAMPLES Next, although an Example is given and this invention is demonstrated in more detail, this invention is not limited to these.

<Examples 1-3, Comparative Examples 1-2>
Polystyrene resin (GPPS (styrene homopolymer) manufactured by DIC, trade name “XC-515”) and a mixed resin of polyphenylene ether resin (PPE) and polystyrene resin (PS) (trade name “manufactured by Subic,” Talc as a nucleating agent in a polystyrene resin composition containing 30 parts by mass of the mixed resin (Noryl EFN 4230) with respect to 100 parts by mass of Noril EFN 4230 ", PPE / PS = 70/30) Was melted and mixed in the extruder. Butane gas was pressed into this as a foaming agent and extruded from a circular die to form a foam sheet. At this time, 30 ° C. air was blown onto the surface of the sheet immediately after being extruded from the circular die and cooled. Adjust the talc mixing amount, butane press-in amount, circular die lip opening, and air ring amount so that the number of cells in the foam sheet, the density, and the surface layer density on the non-laminated surface are the values shown in Table 1. did.

  The number of cells in the thickness direction is cut out from three locations in the width direction of the foam sheet, the cross section of each sample is observed with a magnifying glass, the number of cells arranged in the thickness direction is counted, and the obtained result is the thickness of each sample. It was obtained by dividing and arithmetically averaging. The density was obtained by cutting out 10 cm square samples from 10 locations in the width direction of the foamed sheet, and measuring the weight and thickness of the obtained samples and averaging the results. The surface layer density was obtained by arithmetically averaging the results obtained by cutting out a sample of 1 cm × 5 cm from three locations in the width direction of the foamed sheet, scraping the surface layer portion 150 μm and measuring the weight.

  Each of the obtained foamed sheets was cured for 3 weeks by winding, and a high impact styrene resin (trade name: E785N, manufactured by Toyo Styrene Co., Ltd.) having a resin temperature of 250 ° C. was extruded onto the surface of the foamed sheet with a T-die. 1 was laminated on the surface of the foam sheet as a film having the thickness shown in FIG. This laminated foam sheet was placed on a molding machine (FLC manufactured by Asano Laboratories) so that the film lamination surface was on the inner surface side of the container. At this time, heating and foaming were carried out by adjusting the heating time and heater settings so that the secondary foam thickness and the temperature of the film lamination surface were as shown in Table 1. Thus, a container having a shape similar to that of a square-shaped commercially available yakisoba container with a seal peeling stopper was formed.

  The secondary foamed thickness was obtained by taking the laminated foamed sheet immediately before being molded with the mold used in the molding machine and measuring the thickness at 10 points at equal intervals in the width direction to obtain the average. Moreover, the temperature of the film lamination surface was measured with a non-contact type temperature measuring device Avio's Handy Thermo T VS100, which is the surface temperature of the laminated foamed sheet immediately before being molded with the mold.

Examples 1 to 3 in which the side wall portion of the container was cut out and the cross-sectional structure was observed with a cell scanning electron microscope, and as a result, the surface layer density on the side where the film was not laminated was 0.20 g / cm ³ or more. However, the presence of the fine cells could not be confirmed in Comparative Examples 1 and 2 having a low surface layer density. Therefore, the appearance of Examples 1 to 3 was glossy and very beautiful, but the appearance of Comparative Examples 1 and 2 showed rough bubbles and no high-class feeling.

  Further, the side wall portion of the container was cut out, and a 50% impact when an impact was applied from the film lamination surface side under an atmosphere of −10 ° C. based on the method of JIS-K7211, using a DuPont drop weight impact tester. The breaking energy was measured. As shown in Table 1, the 50% impact fracture energy of Examples 1 to 3 was 0.5 J or more, but Comparative Examples 1 and 2 were less than 0.5 J.

  In addition, these containers are filled with contents (noodles, ingredients, etc.) and sealed with a sealing lid, and then packed in a case of 12 pieces of 6 x 2 steps, and a height of 1.5 m is placed on the box. Then, a 5 kg heavy object was dropped, and the number of broken containers in the case was examined. As a result of the heavy object drop test, as shown in Table 1, no crack occurred in the containers of Examples 1 to 3 having a 50% impact fracture energy of 0.5 J or more, but a comparative example of less than 0.5 J Cracks occurred in the first and second containers.

  As described above, according to the present invention, it is possible to provide a container that is excellent in impact resistance and hardly breaks.

<Reference example>
Below, the resin component is cracked in a polystyrene resin foam sheet made of a polystyrene resin composition of a styrene resin alone and a polystyrene resin foam sheet made of a polystyrene resin composition containing a polyphenylene ether resin. The example which evaluated difficulty is shown.

(Sheet 1)
70% by mass of a polystyrene resin (GPPS (styrene homopolymer) manufactured by DIC, trade name “XC-515”), and a mixed resin of polyphenylene ether resin (PPE) and polystyrene resin (PS) (manufactured by Subic) , Zirconium phosphate deodorant manufactured by Toa Gosei Co., Ltd. as a deodorizing component (trade name “Product name“ Noryl EFN4230 ”, PPE / PS = 70/30) Kesumon NS-10 ") by extrusion foaming the resin composition containing 0.5 parts by mass, thickness 2.0 mm, the foamed sheet having a basis (basis weight) 180 g / m ² was produced.

(Sheet 2)
Instead of a resin composition containing GPPS, PPE, and a deodorizing component, a copolymer of an acrylic monomer and a styrene monomer is extruded and foamed, and a polystyrene resin foam sheet (sheet 2) having the same thickness and the same basis weight as the sheet 1 ) Was produced.

(Sheet 3)
Instead of the resin composition containing GPPS, PPE, and deodorant components, only GPPS was extruded and foamed to produce a polystyrene resin foam sheet (sheet 3) having the same thickness and the same basis weight as sheet 1.

(Heat resistance evaluation: differential scanning calorimetry)
A sample of 6.5 ± 0.5 mg was taken from the above sheet, and differential scanning calorimetry was performed based on JIS K7121 (device used: differential scanning calorimeter, manufactured by SII Nanotechnology, model name “DSC6220” ").
As a result, in the samples of Sheet 1 and Sheet 2, the “midpoint glass transition temperature (Tmg)” described in JIS K7121 9.3 (1) was observed around 120 ° C., and in the sample of Sheet 3, 106 ° C. Observed.

(Toughness evaluation: Dynatap impact test)
A 100 × 100 mm test piece was collected from the sheets 1 to 3 and subjected to a Dynatap impact test based on ASTM D3763 on the test piece (device used: General Research Corp., Dynatap impact) Test device, model name “GRC8250”).
As a result, for the test piece of the sheet 2, the maximum point displacement was 3.2 mm and the maximum load was 29 N, and for the test piece of the sheet 3, the maximum point displacement was 4.0 mm and the maximum load was 36 N.
On the other hand, for the test piece of the sheet 1, the maximum point displacement was 4.4 mm and the maximum load was 42 N.
From this, it can be seen that the sheet 1 is in a state in which displacement and load are difficult to crack due to the inclusion of the PPE resin.

Claims (5)

It contains a polystyrene-based resin and a polyphenylene ether-based resin, and the polyphenylene ether-based resin is 10 parts by mass or more and 50 parts by mass or less with respect to a total of 100 parts by mass of the polystyrene-based resin and the polyphenylene ether-based resin. A polystyrene resin laminated foam sheet in which a polystyrene resin film is laminated on one side of a polystyrene resin foam sheet formed using the contained polystyrene resin composition so that the polystyrene resin film is inside the container. A molded container,
The side wall portion is formed such that a 50% impact fracture energy is 0.5 J or more when an impact is applied at −10 ° C. from the side on which the polystyrene resin film is laminated. container.   The polystyrene-based resin laminated foam sheet is heat-treated and secondarily foamed, and is molded and processed in a state where the surface on which the polystyrene-based resin film is laminated is at a temperature of 100 ° C or higher. The container according to 1. The polystyrene resin film having a thickness of 70 to 200 μm is laminated on one surface of the polystyrene resin foam sheet having a cell number in the thickness direction of 9 to 25 cells / mm and a density of 0.08 to 0.15 g / cm ^3. It is formed using a polystyrene resin laminated foam sheet having a density of 150 μm in the thickness direction from the surface on which the polystyrene resin film is not laminated is 0.20 g / cm ³ or more. The container according to claim 1, wherein the container is characterized. It contains a polystyrene-based resin and a polyphenylene ether-based resin, and the polyphenylene ether-based resin is 10 parts by mass or more and 50 parts by mass or less with respect to a total of 100 parts by mass of the polystyrene-based resin and the polyphenylene ether-based resin. A polystyrene resin laminated foam sheet in which a polystyrene resin film is laminated on one side of a polystyrene resin foam sheet formed using the contained polystyrene resin composition so that the polystyrene resin film is inside the container. A molding method for a container to be molded,
The polystyrene-based resin laminated foam sheet is subjected to heat treatment to perform secondary foaming, and the surface on the side on which the polystyrene-based resin film is laminated is brought to a temperature of 100 ° C. or higher to carry out the molding, whereby the polystyrene-based resin film becomes A container is characterized in that a container is formed such that 50% impact fracture energy measured by applying an impact at −10 ° C. from the laminated side is 0.5 J or more at least in a container side wall portion. Molding method. It contains a polystyrene-based resin and a polyphenylene ether-based resin, and the polyphenylene ether-based resin is 10 parts by mass or more and 50 parts by mass or less with respect to a total of 100 parts by mass of the polystyrene-based resin and the polyphenylene ether-based resin. On one side of a polystyrene resin foam sheet formed using the contained polystyrene resin composition, the number of cells in the thickness direction is 9 to 25 cells / mm, and the density is 0.08 to 0.15 g / cm ^3. , A polystyrene resin laminated foam sheet in which a polystyrene resin film having a thickness of 70 to 200 μm is laminated,
A polystyrene-based resin-laminated foam sheet, wherein the density of a 150 μm portion in the thickness direction from the surface on which the polystyrene-based resin film is not laminated is 0.20 g / cm ³ or more.