Polystyrene resin laminated foam sheet and method for manufacturing the same, and polystyrene resin laminated foam container and method for manufacturing the same

Abstract

To provide a polystyrene resin laminated foam sheet that has excellent peel strength, container strength, heat resistance, and impact resistance, suppresses drawdown during molding, and further improves moldability and productivity.SOLUTION: There is provided a polystyrene resin laminated foam sheet 1 in which a non-foamed resin layer 20 is laminated on one or both sides of a polystyrene resin foam sheet 10, the polystyrene resin foam sheet 10 including a heat-resistant foam layer, and a glass transition temperature (Tg) of resin constituting the heat-resistant foam layer is 110°C or higher, the non-foamed resin layer 20 including a mixed resin containing a polystyrene resin and a polyolefin resin, in which a content of a styrene component in the mixed resin is 27 to 95% by mass based on a total mass of the mixed resin, a content of a butadiene component in the mixed resin is 2.2 to 12% by mass based on the total mass of the mixed resin, and a content of an olefin component in the mixed resin is 0.1 to 70% by mass based on the total mass of the mixed resin.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a polystyrene resin laminated foam sheet, a method for producing the same, a polystyrene resin laminated foam container, and a method for producing the same.

Background Art

[0002] Conventionally, resin foam sheets and molded articles obtained by foaming thermoplastic resins such as polystyrene resins have been used for food containers and the like because of their lightweight and high heat insulation properties. As a method of forming a polystyrene resin foam container (foam container) from a polystyrene resin foam sheet (foam sheet), there is a method of heating the foam sheet to soften it and sandwiching it between molds to obtain a desired shape.

[0003] When forming a foam sheet, a phenomenon called "drawdown" may occur in which the central portion of the foam sheet sags within the heating zone during the heating process. When drawdown occurs, it becomes a cause of appearance defects such as variations in the weight of each container and wrinkles.

[0004] In response to such problems, for example, in Patent Document 1, drawdown is suppressed by laminating an impact-resistant polystyrene resin film provided with stretching on the surface. For example, in Patent Document 2, drawdown is suppressed by blowing cooling air when extruding the foam sheet to impart stretching to the foam sheet itself. For example, in Patent Document 3, a polystyrene resin laminated foam sheet (laminated foam sheet) in which a non-foamed film is laminated on a foam sheet has been proposed.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Patent Document 3

[0006] However, in the technology described in Patent Document 1, if the basis weight of the foamed sheet is heavy, it may not be able to withstand its own weight, and drawdown may not be suppressed. For this reason, it is necessary to change to a thicker high-impact polystyrene resin film depending on the foamed sheet, which makes moldability difficult. In the technology described in Patent Document 2, if productivity is improved by increasing the discharge amount of the foamed sheet, it becomes difficult to control the blowing of cooling air, and there is a risk that a foamed sheet with the desired stretch may not be obtained. For this reason, it is difficult to increase productivity. In the technology described in Patent Document 3, insufficient melt tension of the resin causes poor elongation during molding, resulting in problems with moldability and productivity.

[0007] Therefore, the present invention aims to provide a polystyrene-based resin laminated foam sheet and a method for manufacturing the same, as well as a polystyrene-based resin laminated foam container and a method for manufacturing the same, which are excellent in peel strength, container strength, heat resistance, and impact resistance, can suppress drawdown during molding, and can further improve moldability and productivity. [Means for solving the problem]

[0008] To solve the above problems, the present invention has the following aspects. [1] A non-foamed resin layer is laminated on one or both sides of a polystyrene foam sheet. The aforementioned polystyrene-based foamed sheet includes a heat-resistant foamed layer. The glass transition temperature (Tg) of the resin constituting the heat-resistant foam layer is 110°C or higher. The non-foamed resin layer comprises a mixed resin containing a polystyrene resin and a polyolefin resin. The mixed resin contains a high-impact polystyrene resin having butadiene units, and in the mixed resin, the mass ratio of the high-impact polystyrene resin to the polyolefin resin (high-impact polystyrene resin:polyolefin resin) is 45:55 to 99.9:0.1. The styrene content in the mixed resin is 27 to 95% by mass relative to the total mass of the mixed resin. The content of the butadiene component in the mixed resin is 2.2 to 12% by mass relative to the total mass of the mixed resin. A polystyrene resin laminated foam sheet, wherein the content of the olefin component in the mixed resin is 0.1 to 70% by mass relative to the total mass of the mixed resin. [2] In the aforementioned mixed resin, the polyolefin resin is a polyethylene resin. [1] Polystyrene resin laminated foam sheet as described above. [3] The softening temperature (TS) and the glass transition temperature (Tg) of the mixed resin satisfy the relationship expressed by the following formula (I). [1] or [2] Polystyrene resin laminated foam sheet as described above. [TS-(Tg-26)]≧0(℃) ···(I) [4] The aforementioned mixed resin has a crystallization peak, and the peak temperature of the crystallization peak is 90 to 140°C. The temperature difference between the melting point of the mixed resin and the peak temperature is 1 to 20°C. [1] to [3] Polystyrene resin laminated foam sheet as described above. [5] The polyolefin resin includes high-density polyethylene and low-density polyethylene. [1] to [4] Polystyrene resin laminated foam sheet as described above. [6] The mass ratio of the high-density polyethylene to the low-density polyethylene (high-density polyethylene:low-density polyethylene) is 10:90 to 90:10. [5] Polystyrene resin laminated foam sheet as described above. [7] In the aforementioned mixed resin, the polyolefin resin is a plant-derived resin. [1] to [6] Polystyrene resin laminated foam sheet as described above. [8] A thermoplastic resin film layer is located on one or both sides of the polystyrene foam sheet and on at least one side of one or both sides of the non-foamed resin layer. [1] to [7] Polystyrene resin laminated foam sheet as described above. [9] The heat-resistant foamed layer comprises at least one selected from the group consisting of styrene-acrylic acid copolymer, styrene-methacrylic acid copolymer, and polyphenylene ether resin. [1] to [8] Polystyrene resin laminated foam sheet as described above.

[0009]

[10] [1] to [9] A method for producing a polystyrene resin laminated foam sheet as described above, A method for manufacturing a polystyrene resin laminated foam sheet, comprising a lamination step of extruding and laminating a resin composition containing the mixed resin onto one or both sides of the polystyrene resin foam sheet.

[0010]

[11] A non-foamed resin layer is laminated on one or both sides of a polystyrene foam sheet. The aforementioned polystyrene-based foamed sheet includes a heat-resistant foamed layer. The glass transition temperature (Tg) of the resin constituting the heat-resistant foam layer is 110°C or higher. The non-foamed resin layer comprises a mixed resin containing a polystyrene resin and a polyolefin resin. The mixed resin contains a high-impact polystyrene resin having butadiene units, and in the mixed resin, the mass ratio of the high-impact polystyrene resin to the polyolefin resin (high-impact polystyrene resin:polyolefin resin) is 45:55 to 99.9:0.1. The styrene content in the mixed resin is 27 to 95% by mass relative to the total mass of the mixed resin. The content of the butadiene component in the mixed resin is 2% of the total mass of the mixed resin. It is 0.2 to 12% by mass, A polystyrene resin laminated foam container, wherein the content of the olefin component in the mixed resin is 0.1 to 70% by mass relative to the total mass of the mixed resin.

[12] In the aforementioned mixed resin, the polyolefin resin is a polyethylene resin.

[11] Polystyrene resin laminated foam container as described above.

[13] The softening temperature (TS) and the glass transition temperature (Tg) of the mixed resin satisfy the relationship expressed by the following formula (I).

[11] or

[12] Polystyrene resin laminated foam container as described above. [TS-(Tg-26)]≧0(℃) ···(I)

[14] The aforementioned mixed resin has a crystallization peak, and the peak temperature of the crystallization peak is 90 to 140°C. The temperature difference between the melting point of the mixed resin and the peak temperature is 1 to 20°C.

[11] to

[13] Polystyrene resin laminated foam container as described above.

[15] The polyolefin resin includes high-density polyethylene and low-density polyethylene.

[11] to

[14] Polystyrene resin laminated foam container as described above.

[16] The mass ratio of the high-density polyethylene to the low-density polyethylene (high-density polyethylene:low-density polyethylene) is 10:90 to 90:10.

[15] Polystyrene resin laminated foam container as described above.

[17] In the aforementioned mixed resin, the polyolefin resin is a plant-derived resin.

[11] to

[16] Polystyrene resin laminated foam container as described above.

[18] A thermoplastic resin film layer is located on one or both sides of the polystyrene foam sheet and on at least one side of one or both sides of the non-foamed resin layer.

[11] to

[17] Polystyrene resin laminated foam container as described above.

[19] The heat-resistant foamed layer comprises at least one selected from the group consisting of styrene-acrylic acid copolymer, styrene-methacrylic acid copolymer, and polyphenylene ether resin.

[11] to

[18] Polystyrene resin laminated foam container as described above.

[0011]

[20]

[11] to

[19] A method for manufacturing a polystyrene resin laminated foam container as described above, A lamination step of extruding and laminating a resin composition containing the mixed resin onto one or both sides of the polystyrene foam sheet, A method for manufacturing a polystyrene resin laminated foam container, comprising a molding step of heating and molding the polystyrene resin laminated foam sheet obtained in the lamination step. [Effects of the Invention]

[0012] The polystyrene resin laminated foam sheet of the present invention exhibits excellent peel strength, container strength, heat resistance, and impact resistance, suppresses drawdown during molding, and further improves moldability and productivity. [Brief explanation of the drawing]

[0013] [Figure 1] This is a cross-sectional view showing an example of a polystyrene resin laminated foam sheet of the present invention. [Figure 2] This is a perspective view showing an example of a polystyrene resin laminated foam container of the present invention. [Figure 3] This is the DSC curve of a sample taken from the polystyrene resin laminated foam sheet of Example 1. [Figure 4] This is an example of a TMA curve obtained from TMA measurement of a mixed resin. [Modes for carrying out the invention]

[0014] In this specification, "~" represents a range that includes the values ​​at both ends as the lower and upper limits. The following describes preferred embodiments of the present invention, using a polystyrene resin laminated foam sheet having a non-foamed resin layer on one side of a sheet-like polystyrene resin foam sheet as an example. The polystyrene resin laminated foam sheet may have a non-foamed resin layer on one side of the polystyrene resin foam sheet, or it may have non-foamed resin layers on both sides of the polystyrene resin foam sheet. The polystyrene resin foam sheet may consist of a single foam layer, or it may have two or more foam layers. The non-foamed resin layer may consist of a single non-foamed layer, or it may have two or more non-foamed layers.

[0015] [Polystyrene resin laminated foam sheet] The polystyrene resin laminated foam sheet of the present invention (hereinafter also simply referred to as "laminated foam sheet") comprises a sheet-shaped polystyrene resin foam sheet (hereinafter also simply referred to as "foam sheet") and a non-foamed resin layer laminated on one or both sides of the foam sheet. The foamed sheet includes a heat-resistant foamed layer. The foamed sheet may have a single-layer structure of the heat-resistant foamed layer, or it may have a laminated structure of a heat-resistant foamed layer and a non-heat-resistant foamed layer. In this specification, "heat-resistant foamed layer" refers to a foamed layer in which the glass transition temperature (Tg) of the constituent resin is 110°C or higher, and "non-heat-resistant foamed layer" refers to a foamed layer in which the glass transition temperature (Tg) of the constituent resin is less than 110°C. The non-foamed resin layer contains a mixed resin comprising styrene, butadiene, and olefin components. One embodiment of a laminated foam sheet will be described with reference to the drawings.

[0016] Figure 1 is a cross-sectional view of the laminated foam sheet 1 of this embodiment. The laminated foam sheet 1 has a sheet-shaped foam sheet 10 and a non-foamed resin layer 20 laminated on one side of the foam sheet 10.

[0017] The thickness T1 of the laminated foam sheet 1 can be determined considering the application. For example, the thickness T1 is preferably 0.5 to 7.5 mm, more preferably 0.7 to 5.0 mm, and even more preferably 1.0 to 4.0 mm. If the thickness T1 is above the lower limit, the container strength and impact resistance of the container can be further improved. If the thickness T1 is below the upper limit, the moldability of the laminated foam sheet 1 can be further improved. The thickness T1 can be measured, for example, using a dial thickness gauge.

[0018] The basis weight of laminated foam sheet 1 is, for example, 70-850 g / m². 2 Preferably, 120-700 g / m² 2 More preferably, 200-550 g / m 2 This is even more preferable. If the basis weight of the laminated foam sheet 1 is equal to or greater than the lower limit above, the impact resistance of the container can be further improved. If the basis weight of the laminated foam sheet 1 is equal to or less than the upper limit above, the moldability of the laminated foam sheet 1 can be further improved. The basis weight of laminated foam sheet 1 can be measured by the following method. Excluding the 20 mm at both ends of the laminated foam sheet 1 in the width direction (TD direction), 10 sections of 10 cm x 10 cm are cut at equal intervals in the width direction, and the mass (g) of each section is measured to the nearest 0.001 g. The average mass (g) of each section is measured over 1 m 2 The value converted to mass per unit is the basis weight (g / m²) of laminated foam sheet 1. 2 )

[0019] The apparent density of the laminated foam sheet 1 is, for example, 0.060 to 0.716 g / cm³. 3 Preferably, 0.086~0.540 g / cm³ 3 More preferably, 0.130~0.363 g / cm³ 3 This is even more preferable. If the apparent density of the laminated foam sheet 1 is above the lower limit, the impact resistance of the container can be further improved. If the apparent density of the laminated foam sheet 1 is below the upper limit, the container can be made lighter and its heat insulation can be further improved.

[0020] The apparent density of the laminated foam sheet 1 is determined by measuring in accordance with JIS K7222:2005 "Foamed Plastics and Rubber - Method for Determining Apparent Density". Specifically, for a test piece of the laminated foam sheet 1 cut so as not to change the original cell structure, its mass and apparent volume are measured and calculated by the following formula (1). The apparent density (g / cm 3 ) of the laminated foam sheet 1 = mass of the test piece (g) / apparent volume of the test piece (cm 3 ) ··· (1)

[0021] ≪Foam Sheet≫ The foam sheet 10 is a layer (foamed resin layer) formed by foaming a foaming resin composition containing a polystyrene - based resin, and air bubbles are formed in the resin. The resin contained in the foaming resin composition (that is, the resin constituting the foam sheet 10) is a thermoplastic resin.

[0022] The foam sheet 10 includes a heat - resistant foam layer. In the present embodiment, the foam sheet 10 is formed in a single - layer structure of a heat - resistant foam layer or a two - layer structure of a heat - resistant foam layer and a non - heat - resistant foam layer. That is, the foam sheet 10 is constituted only by the heat - resistant foam layer or is constituted by two layers of a heat - resistant foam layer and a non - heat - resistant foam layer. The glass transition temperature (Tg) of the resin constituting the heat - resistant foam layer is 110°C or higher, preferably 115°C or higher, and more preferably 120°C or higher. When the glass transition temperature (Tg) of the resin constituting the heat - resistant foam layer is at or above the above lower limit value, the heat resistance of the laminated foam sheet 1 can be further enhanced. For this reason, a polystyrene - based resin laminated foam container (hereinafter, also referred to as "foam container") formed by molding the laminated foam sheet 1 can be suitably used as a range - up container. The upper limit value of the glass transition temperature (Tg) of the resin constituting the heat - resistant foam layer is not particularly limited and is, for example, 200°C.

[0023] The glass transition temperature (Tg) of the resin constituting the heat - resistant foam layer is determined by differential scanning calorimetry (DSC) measurement. In this embodiment, when the foamed sheet 10 has a single-layer structure of a heat-resistant foamed layer, the glass transition temperature (Tg) of the resin constituting the heat-resistant foamed layer can be determined by performing a DSC measurement using a sample of the foamed sheet 10 taken from the laminated foamed sheet 1. If the foamed sheet 10 has a two-layer structure consisting of a heat-resistant foamed layer and a non-heat-resistant foamed layer, the glass transition temperature (Tg) of the resin constituting the heat-resistant foamed layer can be determined by performing a DSC measurement using a sample taken from the heat-resistant foamed layer of the foamed sheet 10. The glass transition temperature (Tg) of the resin constituting the heat-resistant foam layer can be adjusted by the type, composition, and combination of raw resins that make up the heat-resistant foam layer.

[0024] Examples of raw material resins that make up the heat-resistant foam layer include styrene-acrylic acid copolymers, styrene-methacrylic acid copolymers, and polyphenylene ether resins. These resins have high glass transition temperatures (Tg) and excellent heat resistance.

[0025] Examples of polystyrene resins include homopolymers or copolymers thereof of styrene monomers such as styrene, α-methylstyrene, vinyltoluene, chlorostyrene, ethylstyrene, i-propylstyrene, dimethylstyrene, and bromostyrene; copolymers mainly composed of styrene monomers, with styrene monomers and vinyl monomers polymerizable thereto; and so-called high-impact polystyrenes, which are copolymers of styrene monomers and rubber components such as butadiene, homopolymers or copolymers thereof, or mixtures or polymers of copolymers of styrene monomers and vinyl monomers and diene-based rubbery polymers.

[0026] Examples of vinyl monomers polymerizable with styrene monomers include alkyl(meth)acrylates such as methyl(meth)acrylate, ethyl(meth)acrylate, butyl(meth)acrylate, and cetyl(meth)acrylate, as well as difunctional monomers such as (meth)acrylonitrile, dimethyl maleate, dimethyl fumarate, diethyl fumarate, ethyl fumarate, divinylbenzene, and alkylene glycol dimethacrylate. These vinyl monomers may be used individually or in combination of two or more. Here, "(meth)acrylate" refers to either or both "acrylate" and "methacrylate," and "(meth)acrylonitrile" refers to either or both "acrylonitrile" and "methacrylonitrile."

[0027] Examples of diene-based rubbery polymers include polybutadiene, styrene-butadiene copolymers, and ethylene-propylene-non-conjugated diene three-dimensional copolymers. These polystyrene resins may be used individually or in combination of two or more types. As for the polystyrene-based resin, a polystyrene-based resin containing 50 mole% or more of units derived from styrene monomer is preferred, and among these, polystyrene is more preferred.

[0028] The polystyrene resin may be general-purpose polystyrene resin (GPPS), commercially available polystyrene resin, or polystyrene resin newly prepared by methods such as suspension polymerization. It may also be polystyrene resin made from recycled materials. Examples of recycled materials include used polystyrene foam molded products, such as fish boxes, home appliance cushioning materials, and food packaging trays, which are collected and recycled using methods such as limonene dissolution or heat volume reduction. Another example of recycled material is scraps generated after punching out food packaging trays from polystyrene foam sheets, which are crushed, melt-kneaded, and re-pelletized. In addition to materials obtained by recycling molded products such as used foam containers, usable recycled materials include non-foamed polystyrene resins collected separately from home appliances (e.g., televisions, refrigerators, washing machines, air conditioners, etc.) and office equipment (e.g., photocopiers, fax machines, printers, etc.).

[0029] The mass-average molecular weight Mw of the polystyrene resin is preferably between 120,000 and 450,000, and more preferably between 150,000 and 400,000. The mass-average molecular weight Mw is a value obtained by converting the value measured by gel permeation chromatography (GPC) based on a calibration curve using standard polystyrene.

[0030] The melt flow rate (MFR) of the polystyrene resin is preferably 0.5 to 6.0 g / 10 min, and more preferably 0.7 to 3.0 g / 10 min. If the MFR of the polystyrene resin is above the lower limit, the strength of the container can be further increased. If the MFR of the polystyrene resin is below the upper limit, the moldability of the foamed sheet 10 can be further increased. In this specification, the MFR of polystyrene resin refers to the value measured in accordance with Method B described in JIS K7210:1999 "Plastics - Test methods for melt mass flow rate (MFR) and melt volume flow rate (MVR) of thermoplastic plastics," under the conditions of a test temperature of 200°C, a test load of 49.03N, and a preheating time of 5 minutes.

[0031] The content of polystyrene resin relative to 100 parts by mass of thermoplastic resin constituting the foamed sheet 10 is preferably 50 parts by mass or more, more preferably 75 parts by mass or more, even more preferably 90 parts by mass or more, and particularly preferably 95 parts by mass or more. When the polystyrene resin content is above the lower limit of the above value, the moldability of the foamed sheet 10 can be further improved, and the rigidity (container strength) of the foamed container, which is the molded body, can be increased. The upper limit of the polystyrene resin content is not particularly limited, and may be 100 parts by mass per 100 parts by mass of thermoplastic resin constituting the foamed sheet 10.

[0032] The foamed resin composition may contain thermoplastic resins other than polystyrene resins. Examples of thermoplastic resins other than polystyrene resins include polyolefin resins such as polyethylene and polypropylene; and polyphenylene ether resins such as poly(2,6-dimethylphenylene-1,4-ether), poly(2,6-diethylphenylene-1,4-ether), and poly(2,6-dichlorophenylene-1,4-ether).

[0033] The foamed resin composition contains a foaming agent. Examples of foaming agents include hydrocarbons such as propane, butane, and pentane; halogenated hydrocarbons such as tetrafluoroethane, chlorodifluoroethane, and difluoroethane; and among these, hydrocarbons are preferred, and butane is preferred. As for butane, n-butane or isobutane may be used individually, or n-butane and isobutane may be used in any proportion. These foaming agents may be used individually or in combination of two or more.

[0034] The amount of foaming agent in the foamed resin composition is preferably, for example, 0.1 to 10 parts by mass, more preferably 1 to 7 parts by mass, and even more preferably 1 to 5 parts by mass, per 100 parts by mass of thermoplastic resin.

[0035] The foamed resin composition may contain other components besides the thermoplastic resin and foaming agent (hereinafter also referred to as "optional foaming layer components"). Examples of optional foaming layer components include foam regulators, stabilizers, UV absorbers, antioxidants, colorants, deodorants, lubricants, flame retardants, and antistatic agents. The type of optional component in the foam layer is determined considering the physical properties required for the foam sheet 10. The optional component in the foam layer may be a single type or a combination of two or more types.

[0036] Examples of foam regulators include mixtures of inorganic powders such as talc and silica. These foam regulators increase the closed-cell ratio of the foamed sheet 10, making it easier to form a foamed layer. Examples of stabilizers include calcium-zinc-based heat stabilizers, tin-based heat stabilizers, and lead-based heat stabilizers. Examples of UV absorbers include cesium oxide-based UV absorbers and titanium dioxide-based UV absorbers. Examples of antioxidants include cerium oxide, cerium oxide / zirconia solid solution, cerium hydroxide, carbon, carbon nanotubes, titanium dioxide, and fullerenes. Examples of colorants include titanium dioxide, carbon black, titanium yellow, iron oxide, ultramarine, cobalt blue, calcined pigments, metallic pigments, mica, pearl pigments, zinc oxide, precipitated silica, and cadmium red. Examples of deodorizers include silica, zeolite, zirconium phosphate, and hydrotalcite calcined products.

[0037] The content of the optional foam layer component in the foamed resin composition is preferably, for example, 0.05 to 20 parts by mass, more preferably 0.1 to 10 parts by mass, and even more preferably 0.3 to 5.0 parts by mass, per 100 parts by mass of thermoplastic resin. When the content of the optional foam layer component is above the lower limit, the effects derived from the optional foam layer component can be exhibited. When the content of the optional foam layer component is below the upper limit, clogging of dies and the like can be prevented more effectively, and the appearance of the foamed sheet 10 can be improved.

[0038] Thickness T of foam sheet 10 10 For example, the thickness T of the foamed sheet 10 is preferably 0.3 to 5.0 mm, more preferably 0.4 to 3.0 mm, and even more preferably 0.5 to 2.5 mm. 10 If the value is above the lower limit mentioned above, the impact resistance of the foam container can be further enhanced. Thickness T of the foam sheet 10 10 If the above upper limit is below this value, the foam container can be made lighter and its moldability can be further improved. Thickness T of foam sheet 10 10 This is determined in the same way as the thickness T1 of the laminated foam sheet 1.

[0039] The basis weight of foam sheet 10 is, for example, 50-600 g / m².2 Preferably, 90-500 g / m² 2 More preferably, 150-400 g / m 2 This is even more preferable. If the basis weight of the foam sheet 10 is above the lower limit, the impact resistance of the foam container can be further improved. If the basis weight of the foam sheet 10 is below the upper limit, the foam container can be made lighter and its moldability can be further improved. In addition, if the basis weight of the foam sheet 10 is below the upper limit, the heating time during heat molding will not be too long, and the productivity of the foam container can be further improved. The basis weight of foamed sheet 10 is determined in the same way as the basis weight of laminated foamed sheet 1.

[0040] The apparent density of the foam sheet 10 is, for example, 0.050 to 0.666 g / cm³. 3 Preferably, 0.066 to 0.500 g / cm³ 3 More preferably, 0.100~0.333 g / cm³ 3 This is even more preferable. If the apparent density of the foam sheet 10 is above the lower limit, the impact resistance of the foam container can be further improved. If the apparent density of the foam sheet 10 is below the upper limit, the foam container can be made lighter and its heat insulation properties can be further improved. The apparent density of the foamed sheet 10 is determined in the same way as the apparent density of the laminated foamed sheet 1.

[0041] The foaming ratio of the foam sheet 10 is preferably 1.5 to 20 times, more preferably 2 to 15 times, and even more preferably 3 to 10 times. If the foaming ratio of the foam sheet 10 is above the lower limit, the impact resistance of the foam container can be further improved. If the foaming ratio of the foam sheet 10 is below the upper limit, the moldability of the foam sheet 10 can be further improved. The foaming ratio of foam sheet 10 is 1, which is the apparent density of foam sheet 10 (g / cm³). 3 This is the value obtained by dividing by ")".

[0042] The average bubble diameter of the foamed sheet 10 is preferably 80 to 450 μm, more preferably 150 to 400 μm, and even more preferably 200 to 350 μm. If the average bubble diameter of the foamed sheet 10 is above the lower limit, the impact resistance of the foamed container can be further improved. If the average bubble diameter of the foamed sheet 10 is below the upper limit, the surface smoothness of the foamed container can be further improved. The average bubble diameter of the foamed sheet 10 can be measured in accordance with the method described in ASTM D2842-69.

[0043] The closed-cell ratio of the foamed sheet 10 is preferably 70% or more, more preferably 80% or more, even more preferably 90% or more, and may be 100%. The closed-cell ratio of the foamed sheet 10 can be measured in accordance with the method described in JIS K7138:2006 "Rigid foamed plastics - Method for determining open-cell ratio and closed-cell ratio".

[0044] The proportion of the heat-resistant foam layer in the foam sheet 10 is preferably 30% by mass or more, more preferably 40% by mass or more, even more preferably 50% by mass or more, and may be 100% by mass, based on the mass of the foam sheet 10. If the proportion of the heat-resistant foam layer in the foam sheet 10 is above the lower limit of the above value, the heat resistance of the laminated foam sheet 1 can be further improved. The proportion of the heat-resistant foam layer in the foam sheet 10 can be calculated from the mass of the resin constituting the heat-resistant foam layer relative to the total mass of the resin constituting the foam sheet 10.

[0045] ≪Non-foamed resin layer≫ The non-foamed resin layer 20 contains a mixed resin comprising a polystyrene resin and a polyolefin resin, and is a layer in which substantially no air bubbles are formed. In addition, the non-foamed resin layer 20 is a layer that substantially does not contain a foaming agent. Although the non-foamed resin layer 20 is a layer in which substantially no air bubbles are formed, it may contain a small amount of foaming agent when the non-foamed resin layer 20 is formed by a co-extrusion method, etc.

[0046] The mixed resin includes a polystyrene-based resin and a polyolefin-based resin. In this specification, "mixed resin" refers to all resin components in the resin composition constituting the non-foamed resin layer 20. The polystyrene resin MFR is the same as the polystyrene resin MFR that constitutes the foamed sheet 10 described above.

[0047] When the polyolefin resin is a polyethylene resin, the MFR of the polyethylene resin is preferably 0.1 to 15.0 g / 10 min, and more preferably 0.2 to 8.0 g / 10 min. If the MFR of the polyethylene resin is above the lower limit, the fluidity during melting is good, and productivity can be further increased. If the MFR of the polyethylene resin is below the upper limit, the elongation during molding is good, and moldability can be further increased. In this specification, the MFR of polyethylene resin refers to the value measured in accordance with Method B described in JIS K7210:1999 "Plastics - Test methods for melt mass flow rate (MFR) and melt volume flow rate (MVR) of thermoplastic plastics," under the conditions of a test temperature of 190°C, a test load of 21.18 N, and a preheating time of 5 minutes.

[0048] When the polyolefin resin is a polypropylene resin, the MFR of the polypropylene resin is preferably 2.0 to 20.0 g / 10 min, and more preferably 4.0 to 14.0 g / 10 min. If the MFR of the polypropylene resin is above the lower limit, the fluidity during melting is good, and productivity can be further increased. If the MFR of the polypropylene resin is below the upper limit, the elongation during molding is good, and moldability can be further increased. In this specification, the MFR of polypropylene resin refers to the value measured in accordance with Method B described in JIS K7210:1999 "Plastics - Test methods for melt mass flow rate (MFR) and melt volume flow rate (MVR) of thermoplastic plastics," under the conditions of a test temperature of 230°C, a test load of 21.18 N, and a preheating time of 5 minutes.

[0049] In this specification, the styrene component refers to the styrene monomer obtained when the mixed resin is heated and decomposed. The styrene component originates from the polystyrene resin contained in the mixed resin. Examples of polystyrene resins include those similar to the polystyrene resin that constitutes the foamed sheet 10. Among these, those containing high-impact polystyrene resin are preferred. By including high-impact polystyrene resin in the mixed resin, the impact resistance of the foamed container can be further enhanced.

[0050] In this specification, the butadiene component refers to the butadiene monomer and 4-vinyl-1-cyclohexene monomer obtained when the mixed resin is heated and decomposed. The butadiene component originates from the polystyrene resin contained in the mixed resin.

[0051] In this specification, the olefin component refers to the olefin monomer obtained when the mixed resin is heated and decomposed. The olefin component originates from the polyolefin resin contained in the mixed resin. Examples of polyolefin resins include polyethylene resins and polypropylene resins. Among the polyolefin resins, polyethylene resins are preferred because they provide good moldability to the mixed resin when mixed with polystyrene resins. Examples of polyethylene resins include high-density polyethylene (HDPE), medium-density polyethylene (MDPE), low-density polyethylene (LDPE), and linear low-density polyethylene (LLDPE). Among polyethylene resins, HDPE is preferred because it can provide higher container strength. In this specification, high-density polyethylene refers to a resin density of 0.940 g / cm³. 3 More than 0.970g / cm 3 The following polyethylene resins are referred to. Medium-density polyethylene refers to a resin density of 0.930 g / cm³. 3 Super 0.940g / cm 3 This refers to polyethylene resins with a density of less than 0.910 g / cm³. Low-density polyethylene is defined as a resin with a density of 0.910 g / cm³. 3 More than 0.930g / cm 3The following polyethylene-based resins are referred to. Linear low-density polyethylene refers to low-density polyethylene in a linear configuration. The resin density of polyethylene-based resins can be measured in accordance with the method described in JIS K7112:1999 "Plastics - Method for determining the density and specific gravity of non-foamed plastics," Method B (pycnometer method).

[0052] Polyolefin resins are preferably made of high-density polyethylene and low-density polyethylene, as this enhances their lamination properties. When the polyolefin resin contains high-density polyethylene and low-density polyethylene, the mass ratio of high-density polyethylene to low-density polyethylene (high-density polyethylene:low-density polyethylene) is preferably 10:90 to 90:10, more preferably 20:80 to 80:20, and even more preferably 30:70 to 70:30. When the mass ratio of high-density polyethylene to low-density polyethylene is 10:90 or higher, drawdown during molding of the foamed sheet 10 can be further suppressed. When the mass ratio of high-density polyethylene to low-density polyethylene is 90:10 or lower, the melt elongation of the mixed resin can be further increased, and the take-up stability can be further improved. Here, "lamination processability" is one of the indicators used to evaluate the moldability of the non-foamed resin layer 20 when extruding the mixed resin, and can be evaluated from neck-in and take-up stability. In this specification, "neck-in" refers to the neck-in phenomenon, which is the phenomenon in which the thickness of both ends of the non-foamed resin layer 20 in the width direction (TD direction) increases. "Take-up stability" refers to suppressing fluctuations in the thickness of the non-foamed resin layer 20 when the take-up speed is increased when taking up the non-foamed resin layer 20. By improving the lamination properties, the moldability of the non-foamed resin layer 20 can be further enhanced, and the productivity of the laminated foam sheet 1 can be further increased.

[0053] The polyolefin resin included in the mixed resin is preferably a plant-derived resin because it can reduce the environmental impact. Examples of plant-derived resins include polymers derived from plant materials such as sugarcane and corn. "Derived from plant materials" refers to polymers synthesized or extracted from plant materials. For example, "derived from plant materials" refers to polymers in which monomers synthesized or extracted from plant materials are polymerized. "Monomers synthesized or extracted from plant materials" includes monomers synthesized using compounds synthesized or extracted from plant materials as raw materials. Plant-derived resins include those in which a portion of the monomers are "derived from plant materials". Examples of plant-derived resins include so-called bio-PE, bio-PP, plant-derived polyethylene resins, and plant-derived polypropylene resins.

[0054] The styrene content in the mixed resin is 27 to 95% by mass relative to the total mass of the mixed resin, preferably 40 to 93% by mass, and more preferably 50 to 90% by mass. If the styrene content in the mixed resin is above the lower limit, the peel strength can be further increased. If the styrene content in the mixed resin is below the upper limit, the drawdown during molding of the foamed sheet 10 can be further suppressed. The styrene content in the mixed resin can be determined by the method described in the examples.

[0055] The butadiene content in the mixed resin is 2.2 to 12% by mass relative to the total mass of the mixed resin, preferably 3.2 to 10% by mass, and more preferably 4.1 to 8.0% by mass. If the butadiene content in the mixed resin is above the lower limit, the impact resistance and moldability of the container can be further improved. If the butadiene content in the mixed resin is below the upper limit, the strength of the container can be further improved. The butadiene content in the mixed resin can be determined by the method described in the examples.

[0056] The olefin component content in the mixed resin is 0.1 to 70% by mass relative to the total mass of the mixed resin, preferably 2 to 50% by mass, and more preferably 3 to 40% by mass. If the olefin component content in the mixed resin is above the lower limit, drawdown during molding can be further suppressed. If the olefin component content in the mixed resin is below the upper limit, the container strength and peel strength can be further increased. The content of the olefin component in the mixed resin can be determined by the method described in the examples.

[0057] When the mixed resin contains a high-impact polystyrene resin, the mass ratio of the high-impact polystyrene resin to the polyolefin resin in the mixed resin (high-impact polystyrene resin: polyolefin resin) is 45:55 to 99.9 : A ratio of 0.1 is preferred, 50:50 to 98:2 is more preferred, and 60:40 to 95:5 is even more preferred. When the mass ratio of high-impact polystyrene resin to polyolefin resin in the mixed resin is within the above numerical range, the container strength and impact resistance of the container are excellent, and drawdown during molding can be further suppressed.

[0058] The resin composition constituting the non-foamed resin layer 20 includes a mixed resin. The resin composition containing the mixed resin preferably contains a compatibilizer to improve the dispersibility of the polyolefin resin in the polystyrene resin. Any compatibilizer capable of compatibilizing polystyrene resins and polyolefin resins is acceptable, and conventionally known compatibilizers can be used. The use of styrene-based thermoplastic elastomers is particularly preferred as the compatibilizer. Styrene-based thermoplastic elastomers are excellent in flexibility and elasticity and possess rubber-like properties. Examples of styrene-based thermoplastic elastomers include elastomers of styrene, butadiene, and styrene (SBS type), elastomers of styrene, isoprene, and styrene (SIS type), and hydrogenated styrene-based thermoplastic elastomers obtained by hydrogenating these. Examples of hydrogenated styrene-based thermoplastic elastomers include elastomers of styrene, ethylene, butylene, and styrene (SEBS type), elastomers of styrene, butadiene, butylene, and styrene (SBBS type), and elastomers of styrene, ethylene, propylene, and styrene (SEPS type). Among these, SEBS-type hydrogenated styrene-based thermoplastic elastomers are preferred as the compatibilizer because they can further improve the dispersibility of polyolefin resins in high-impact polystyrene resins.

[0059] When the resin composition contains a compatibilizer, the compatibilizer content is preferably 1 to 20 parts by mass, more preferably 2 to 15 parts by mass, and even more preferably 3 to 10 parts by mass, based on 100 parts by mass of the total amount of polystyrene resin and polyolefin resin. When the compatibilizer content is within the above numerical range, the dispersibility of the polyolefin resin in the polystyrene resin can be further improved.

[0060] In the non-foamed resin layer 20, the peak temperature (Tc) of the crystallization peak of the mixed resin, measured using a thermal flux differential scanning calorimetry (DSC) device, is preferably 90 to 140°C, more preferably 95 to 130°C, and even more preferably 100 to 125°C. If the peak temperature (Tc) of the crystallization peak of the mixed resin is above the lower limit, drawdown during molding can be further suppressed. If the peak temperature (Tc) of the crystallization peak of the mixed resin is below the upper limit, moldability can be further improved. The peak temperature (Tc) of the crystallization peak of the mixed resin is determined by the method described in the examples. The peak temperature (Tc) of the crystallization peak of a mixed resin can be adjusted by the type of mixed resin, its composition, and combinations thereof.

[0061] The melting point (Tm) of the mixed resin in the non-foamed resin layer 20 is preferably 100 to 160°C, more preferably 105 to 150°C, and even more preferably 110 to 140°C. When the melting point (Tm) of the mixed resin in the non-foamed resin layer 20 is within the above numerical range, moldability can be further improved. The melting point (Tm) of the mixed resin in the non-foamed resin layer 20 is determined by the method described in the examples. The melting point (Tm) of the mixed resin in the non-foamed resin layer 20 can be adjusted by the type of mixed resin, the composition of the mixed resin, and combinations thereof.

[0062] The temperature difference (Tm-Tc) between the melting point (Tm) of the mixed resin in the non-foamed resin layer 20 and the peak temperature of the crystallization peak (Tc) of the mixed resin (hereinafter also referred to as the "supercooling temperature difference") is preferably 1 to 20°C, more preferably 5 to 17°C, and even more preferably 11 to 14°C. When the supercooling temperature difference (Tm-Tc) is within the above numerical range, drawdown during molding can be further suppressed. The supercooling temperature difference (Tm-Tc) can be calculated from the melting point (Tm) of the mixed resin and the peak temperature of the crystallization peak (Tc) of the mixed resin.

[0063] The softening temperature of the mixed resin in the non-foamed resin layer 20 is preferably 96 to 140°C, more preferably 100 to 130°C, and even more preferably 107 to 125°C. If the softening temperature of the mixed resin in the non-foamed resin layer 20 is above the lower limit, drawdown during molding can be further suppressed. If the softening temperature of the mixed resin in the non-foamed resin layer 20 is below the upper limit, moldability can be further improved. The softening temperature of the mixed resin in the non-foamed resin layer 20 can be measured in accordance with the method described in JIS K7196:1991 "Test method for softening temperature of thermoplastic plastic films and sheets by thermomechanical analysis". The softening temperature of the mixed resin in the non-foamed resin layer 20 can be adjusted by the type of mixed resin, the composition of the mixed resin, and combinations thereof.

[0064] Preferably, the softening temperature (TS) of the mixed resin and the glass transition temperature (Tg) of the resin constituting the heat-resistant foam layer satisfy the relationship expressed by the following formula (I). [TS-(Tg-26)]≧0(℃) ···(I) The left-hand side of equation (I) is preferably 0°C or higher, more preferably 4°C or higher, and even more preferably 11°C or higher. When the left-hand side of equation (1) is above the lower limit, a laminated foam sheet 1 with good moldability can be obtained while suppressing drawdown. The upper limit of the left-hand side of equation (I) is not particularly limited and is, for example, 65°C.

[0065] The resin density of the mixed resin in the non-foamed resin layer 20 is 0.990 to 1.039 g / cm³. 3 Preferably, 1,000 to 1,038 g / cm³ 3 More preferably, 1.010 to 1.037 g / cm³ 3 This is even more preferable. If the resin density of the mixed resin in the non-foamed resin layer 20 is above the above lower limit, the strength of the container can be further increased. If the resin density of the mixed resin in the non-foamed resin layer 20 is below the above upper limit, drawdown during molding can be further suppressed. The resin density of the mixed resin in the non-foamed resin layer 20 is determined by the method described in the examples. The resin density of the mixed resin in the non-foamed resin layer 20 can be adjusted by the type of mixed resin, the composition of the mixed resin, and combinations thereof.

[0066] The melt tension of the non-foamed resin layer 20 is preferably 2.1 cN or higher, more preferably 2.6 cN or higher, and even more preferably 3.4 cN or higher. When the melt tension of the non-foamed resin layer 20 is above the lower limit, the elongation during molding is good, and moldability can be further improved. The upper limit of the melt tension of the non-foamed resin layer 20 is not particularly limited, and is, for example, 8 cN or lower. The melt tension of the non-foamed resin layer 20 is determined by the method described in the examples. The melt tension of the non-foamed resin layer 20 can be adjusted by the type of mixed resin, the composition of the mixed resin, and combinations thereof.

[0067] Thickness T of the non-foamed resin layer 20 20 The thickness of the non-foamed resin layer 20 is preferably 15 to 400 μm, more preferably 30 to 300 μm, even more preferably 50 to 200 μm, and particularly preferably 90 to 160 μm. 20 If the value is above the lower limit mentioned above, the container strength can be further increased. Thickness T of the non-foamed resin layer 20 20 If the above upper limit is below this value, the moldability can be further improved. Thickness T of the non-foamed resin layer 20 20 This can be determined by observing the cross-section of the laminated foam sheet 1, which has been cut in the thickness direction, using a microscope or the like.

[0068] The resin composition constituting the non-foamed resin layer 20 may contain other components besides the mixed resin (hereinafter also referred to as "optional components"). Examples of optional components include those similar to the optional components of the foamed layer described above. When the resin composition contains optional components, the content of the optional components is preferably, for example, 0.05 to 10 parts by mass, more preferably 0.1 to 5.0 parts by mass, and even more preferably 0.3 to 3.0 parts by mass, based on 100 parts by mass of the total amount of polystyrene resin and polyolefin resin. If the content of the optional components is above the lower limit, the effects derived from the optional components can be exhibited. If the content of the optional components is below the upper limit, the fluidity during melting is good, and productivity can be further increased.

[0069] [Manufacturing method for laminated foam sheets] One example of a method for manufacturing the laminated foam sheet 1 is to manufacture a base sheet that will become the foam sheet 10 (base sheet manufacturing step), and then to extrude a resin composition containing a mixed resin onto one or both sides of the base sheet to laminate it (lamination step).

[0070] Conventional manufacturing methods can be used for the raw material sheet manufacturing process. First, a raw material composition containing a thermoplastic resin and other components, along with a foaming agent, is supplied to an extruder, melted, and kneaded to obtain a foamable resin composition. The melting temperature (set temperature) for the thermoplastic resin is preferably, for example, 180 to 270°C. If the melting temperature is above the lower limit, the resin and other raw materials can be mixed uniformly. If the melting temperature is below the upper limit, the decomposition of the resin can be suppressed.

[0071] Lamination processes include methods such as extruding a resin composition onto the surface of a raw material sheet using an extruder (T-die) (T-die method), and obtaining a laminated foamed sheet 1 in which a non-foamed resin layer 20 is provided on the foamed sheet 1 by co-extrusion (co-extrusion method).

[0072] In the lamination process, the basis weight of the resin composition extruded from the extruder is, for example, 15 to 400 g / m². 2 Preferably, 30-300 g / m 2 More preferably, 50-200 g / m 2 More preferably, 90-160 g / m² 2 This is particularly preferable. If the basis weight of the resin composition extruded from the extruder is equal to or greater than the above lower limit, a laminated foamed sheet 1 with a sufficiently thick non-foamed resin layer 20 can be obtained. This further suppresses drawdown during molding. If the basis weight of the resin composition extruded from the extruder is equal to or less than the above upper limit, moldability can be further improved.

[0073] The take-up speed when taking up the non-foamed resin layer 20 with the take-up machine is not particularly limited, but for example, 10 to 30 m / min is preferred, 13 to 28 m / min is more preferred, and 20 to 26 m / min is even more preferred. If the take-up speed is above the lower limit, the productivity of the non-foamed resin layer 20 can be further increased. If the take-up speed is below the upper limit, the lamination processability of the non-foamed resin layer 20 can be further increased.

[0074] The laminated foam sheet 1 may be manufactured by separately producing a base sheet and a non-foamed layer base sheet that will become the non-foamed resin layer 20, stacking the base sheet and the non-foamed layer base sheet, and then heat-pressing them together (heat-pressing method). Alternatively, the base sheet and the non-foamed layer base sheet may be stacked and bonded together with an adhesive (bonding method).

[0075] The non-foamed layer base material may be manufactured by pre-melting and mixing two or more resin pellets that will be used as raw materials for the non-foamed layer base material, then again forming pellets (mixed pellets), which are then supplied to an extruder, melted, and kneaded to produce the non-foamed layer base material. As a method for manufacturing the non-foamed layer base material, the mixed pellets may be subjected to the T-die method or the co-extrusion method. Alternatively, without producing mixed pellets, the non-foamed layer base material may be manufactured by supplying one or more resin pellets to an extruder, melting, and kneading them. From the viewpoint of further improving the dispersibility of the mixed resin and further improving the impact resistance of the foamed container, it is preferable to form the non-foamed resin layer using mixed pellets.

[0076] According to this embodiment, since a non-foaming resin layer 20 is laminated on one or both sides, drawdown during molding can be suppressed. In addition, the non-foaming resin layer 20 of this embodiment has a specific range of styrene, butadiene, and olefin content in the mixed resin, thus increasing the peel strength. Furthermore, because the non-foaming resin layer 20 of this embodiment has a specific range of styrene, butadiene, and olefin content in the mixed resin, it exhibits good elongation during molding, further improving moldability.

[0077] In this embodiment, it is preferable that the laminated foam sheet 1 has a thermoplastic resin film layer (not shown) on one or both sides. The laminated foam sheet 1 may have a thermoplastic resin film layer on only one side, or it may have a thermoplastic resin film layer on both sides. That is, it is preferable that the thermoplastic resin film layer is located on at least one side of one or both sides of the foam sheet 10 and one or both sides of the non-foamed resin layer 20. When the laminated foam sheet 1 has a thermoplastic resin film layer, it is more preferable that the thermoplastic resin film layer is laminated on both or either the surface (outermost surface) 11 of the foam sheet 10 and the surface (outermost surface) 21 of the non-foamed resin layer 20. By laminating the thermoplastic resin film layer, the strength of the laminated foam sheet 1 and the foam container can be improved. In addition, oil resistance, design properties, surface smoothness, printability, oxygen barrier properties, water vapor barrier properties, etc., can be imparted to the laminated foam sheet 1 and the foam container. A thermoplastic resin film layer may be provided at the interface 30 between the foamed sheet 10 and the non-foamed resin layer 20, to the extent that it does not impede the effects of the present invention.

[0078] The thermoplastic resin film layer may consist of a single film layer or may have two or more film layers. The thermoplastic resin film layer may be an unoriented film, or a uniaxially or biaxially oriented stretched film. The thermoplastic resin film layer is preferably made from plant-derived resin, as this reduces the environmental impact. Since the thermoplastic resin film layer can be given aesthetic appeal, it is preferable that it has a printed layer with a printed pattern or the like. The thickness of the thermoplastic resin film layer is preferably, for example, 10 to 200 μm, more preferably 13 to 150 μm, and even more preferably 15 to 80 μm.

[0079] Examples of thermoplastic resin film layers include polystyrene resin films, polyolefin resin films such as polypropylene resins and polyethylene resins, polyester resin films such as polyethylene terephthalate resins, polybutylene terephthalate resins, polyethylene furanoate resins, polybutylene succinate resins, and polylactic acid resins, polyamide resin films, and ethylene vinyl alcohol resin films. Polystyrene resin films are preferred because they exhibit excellent adhesion between the foamed sheet 10 and the non-foamed resin layer 20, allowing them to be laminated by a heat-pressing method. Polypropylene resin films are preferable because they can impart oil resistance to laminated foam sheets and foam containers. Polyolefin resin films such as polyethylene resins and polypropylene resins, polyester resin films, polyamide resin films, and ethylene vinyl alcohol resin films are preferred because they can provide gas barrier properties against oxygen and water vapor.

[0080] The following are some examples of methods for laminating thermoplastic resin film layers. (1) A method of stacking a thermoplastic resin film layer and a foamed sheet 10 in this order and then heat-pressing them together (thermo-press method), or a method of stacking a thermoplastic resin film layer and a non-foamed resin layer 20 in this order and then heat-pressing them together (thermo-press method). (2) A method of stacking the thermoplastic resin film layer and the foam sheet 10 in this order and bonding each layer with an adhesive (bonding method), or a method of stacking the thermoplastic resin film layer and the non-foamed resin layer 20 in this order and bonding each layer with an adhesive (bonding method). (3) A method of extruding the resin that will be used as the raw material for the thermoplastic resin film layer onto the surface of the foamed sheet 10 or the surface of the non-foamed resin layer 20 using a T-die (T-die method). (4) A method for obtaining a laminate in which a thermoplastic resin film layer is provided on a foamed sheet 10 by co-extrusion (co-extrusion method), or a method for obtaining a laminate in which a thermoplastic resin film layer is provided on a non-foamed resin layer 20 by co-extrusion (co-extrusion method).

[0081] [Polystyrene resin laminated foam container] The polystyrene resin laminated foam container of the present invention (hereinafter also referred to as "foam container") is formed by molding the laminated foam sheet of the present invention described above. Examples of molded products include trays with a plan view shape such as a perfect circle, ellipse, semicircle, polygon, or fan shape; bowl-shaped containers; cylindrical or rectangular containers with bottoms; containers with lids such as those for natto; and lids that are attached to the container body. These containers are preferably used for food, and more preferably for microwave heating food.

[0082] One embodiment of the foamed container of the present invention will be described with reference to the drawings. The foamed container 100 in Figure 2 is a bowl-shaped container with a perfectly circular shape in plan view. The foamed container 100 has a circular bottom wall 110 and side walls 120 that rise from the periphery of the bottom wall 110. The side walls 120 widen outwards towards the top. The foamed container 100 has an opening 130 enclosed by the upper end of the side wall 120. The opening 130 enclosed by the upper end of the side wall 120 is perfectly circular in plan view. The bottom wall 110 is formed from a convex portion 112 that is perfectly circular in plan view and convex in the direction of the opening 130, and an annular recess 114 that surrounds the convex portion 112. The foamed container 100 is suitably used as a food container for storing instant noodles and other similar items, and for consuming them by pouring hot water over them.

[0083] Although the foam container 100 in this embodiment is perfectly circular in plan view, the present invention is not limited to this. The plan view shape of the foam container may be elliptical or polygonal.

[0084] The foamed container 100 may have a non-foamed resin layer only on its inner surface, or a non-foamed resin layer only on its outer surface, or it may have a non-foamed resin layer on both its inner and outer surfaces. The foamed container 100 preferably has a thermoplastic resin film layer. The foamed container 100 may have a thermoplastic resin film layer only on the inner surface, or only on the outer surface, or it may have a thermoplastic resin film layer on both the inner and outer surfaces.

[0085] [Method for manufacturing foamed containers] One example of a method for manufacturing a foamed container is to heat and soften a laminated foamed sheet (heating step), and then mold it by sandwiching it between a female mold and a male mold (molding step) (thermoforming method).

[0086] The heating process involves heating and softening the laminated foam sheet. The heating temperature in the heating process should be such that the laminated foam sheet softens, for example, 80 to 150°C.

[0087] The molding process involves sandwiching a heated laminated foam sheet between a female mold and a male mold to obtain a container of any shape. In this process, the laminated foam sheet of the present invention has a non-foamed resin layer containing a mixed resin laminated on one or both sides, which suppresses drawdown. In addition, the non-foamed resin layer of this embodiment has a specific range of styrene, butadiene, and olefin content in the mixed resin, thus improving peel strength, container strength, and impact resistance. Furthermore, the non-foamed resin layer of this embodiment has a specific range of styrene, butadiene, and olefin content in the mixed resin, resulting in good elongation during molding and further improving moldability.

[0088] Examples of molding methods in the molding process include conventionally known thermoforming methods such as vacuum forming, pressure forming, or applications thereof such as free drawing forming, plug-and-ridge forming, ridge forming, matched mold forming, straight forming, drape forming, reverse draw forming, air slip forming, plug-assisted forming, and plug-assisted reverse load forming.

[0089] The temperature of the mold in the molding process is not particularly limited, but is preferably 50 to 150°C, and more preferably 60 to 130°C. If the mold temperature is above the lower limit, the molding speed can be increased, and productivity can be further increased. If the mold temperature is below the upper limit, the melting of the laminated foam sheet can be prevented.

[0090] After molding the laminated foam sheet into the desired shape within the mold, the mold is opened and the foam container portion is punched out from the laminated foam sheet. By punching out the foam container portion from the laminated foam sheet, a foam container is obtained.

[0091] In a foamed container, the non-foamed resin layer is preferably located on the inner surface of the container. By having the non-foamed resin layer on the inner surface, it is possible to suppress the penetration of contents into the container. The non-foamed resin layer may also be located on the outer surface of the container. In this case, from the viewpoint of suppressing the penetration of contents into the container, it is preferable to provide a thermoplastic resin film layer on the inner surface of the container.

[0092] In the case of a foamed sheet with a laminated structure of a heat-resistant foamed layer and a non-heat-resistant foamed layer, it is preferable that the heat-resistant foamed layer be located on the inner surface of the foamed container. By having the heat-resistant foamed layer located on the inner surface of the container, deformation and expansion of the container can be suppressed even when food or other items are heated in a microwave oven or the like while it is inside.

[0093] As explained above, the foamed container of the present invention has a non-foamed resin layer containing a mixed resin laminated on one or both sides, which enhances the strength and impact resistance of the container. In addition, according to the foamed container of the present invention, the foamed sheet contains a heat-resistant foamed layer, which further enhances heat resistance. [Examples]

[0094] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0095] (Raw materials used) Polystyrene resin • E641N: High-impact polystyrene, product name "E641N" (manufactured by Toyo Styrene Co., Ltd.), butadiene content: 6% by mass, resin density: 1.04 g / cm³ 3 . • XL5: High-impact polystyrene, product name "XL5" (manufactured by Toyo Styrene Co., Ltd.), butadiene content: 13% by mass, resin density: 1.04 g / cm³ 3 . • 475D: High-impact polystyrene, product name "475D" (manufactured by PS Japan Co., Ltd.), butadiene content: 3.9% by mass, resin density: 1.04 g / cm³ 3 . • HRM26: General-purpose polystyrene, product name "HRM26" (manufactured by Toyo Styrene Co., Ltd.), resin density: 1.05 g / cm³ 3 . • HP555: General-purpose polystyrene, product name "HP555" (manufactured by DIC Corporation), resin density: 1.05 g / cm³ 3 .

[0096] Polyolefin resins • SGF4960: High-density polyethylene (HDPE), product name "SGF4960" (plant-derived, manufactured by Braskem), MFR: 0.34 g / 10 min, resin density: 0.961 g / cm³ 3 . • SGF4950: High-density polyethylene (HDPE), product name "SGF4950" (plant-derived, manufactured by Braskem), MFR: 0.34 g / 10 min, resin density: 0.956 g / cm³ 3 . • SGE7252NS: High-density polyethylene (HDPE), product name "SGE7252NS" (plant-derived, manufactured by Braskem), MFR: 2.2g / 10min, resin density: 0.953g / cm³ 3 . • SHC7260: High-density polyethylene (HDPE), product name "SHC7260" (plant-derived, manufactured by Braskem), MFR: 7.2g / 10min, resin density: 0.959g / cm³ 3 . • HY540: High-density polyethylene (HDPE), product name "HY540" (petroleum-derived, manufactured by Nippon Polyethylene Co., Ltd.), MFR: 1.0g / 10min, resin density: 0.946g / cm³ 3 . • J241: High-density polyethylene (HDPE), product name "J241" (petroleum-derived, manufactured by Asahi Kasei Corporation), MFR: 5.0g / 10min, resin density: 0.964g / cm³ 3 . • SBF0323HC: Low-density polyethylene (LDPE), product name "SBF0323HC" (plant-derived, manufactured by Braskem), MFR: 0.32g / 10min, resin density: 0.923g / cm³ 3 . • SLL118: Linear low-density polyethylene (LLDPE), product name "SLL118" (plant-derived, manufactured by Braskem), MFR: 1.0g / 10min, resin density: 0.918g / cm³ 3 . • PM600A: Homopolypropylene (PP), product name "PM600A" (petroleum-derived, manufactured by Sun Allomer Co., Ltd.), MFR: 8.0g / 10min, resin density: 0.900g / cm³ 3 .

[0097] ≪Resin that makes up the heat-resistant foam layer≫ MMA-1: A resin obtained by uniformly mixing 80 parts by mass of styrene-methacrylic acid copolymer (product name "TO80", manufactured by Toyo Styrene Co., Ltd.) and 20 parts by mass of high-impact polystyrene resin (product name "H8117", manufactured by PS Japan Co., Ltd.). MMA-2: A resin obtained by uniformly mixing 80 parts by mass of styrene-methacrylic acid copolymer (product name "G9001", manufactured by PS Japan Co., Ltd.) and 20 parts by mass of high-impact polystyrene resin (product name "H8117", manufactured by PS Japan Co., Ltd.). MMA-3: A resin obtained by uniformly mixing 80 parts by mass of styrene-methacrylic acid copolymer (product name "G9001", manufactured by PS Japan Co., Ltd.) and 20 parts by mass of high-impact polystyrene resin (product name "H8117", manufactured by PS Japan Co., Ltd.). PPE-1: A resin obtained by uniformly mixing 30 parts by mass of polyphenylene ether resin (product name "Noryl EFN4230", manufactured by Sabic Co., Ltd.) and 70 parts by mass of polystyrene resin (product name "XC515", manufactured by DIC Corporation). PPE-2: A resin uniformly mixed with 39 parts by mass of polyphenylene ether resin (product name "Noryl EFN4230", manufactured by Sabic Co., Ltd.), 41 parts by mass of polystyrene resin (product name "HP555", manufactured by DIC Corporation), and 20 parts by mass of high-impact polystyrene resin (product name "E641N" (manufactured by Toyo Styrene Co., Ltd.)). PPE-3: A resin obtained by uniformly mixing 30 parts by mass of polyphenylene ether resin (product name "Noryl EFN4230", manufactured by Sabic Co., Ltd.) and 70 parts by mass of polystyrene resin (product name "XC515", manufactured by DIC Corporation).

[0098] <Compatibilizer> • H1043: Hydrogenated styrene-based thermoplastic elastomer (SEBS type), product name "ToughTec (registered trademark) H1043" (manufactured by Asahi Kasei Corporation), resin density: 0.970 g / cm³ 3 The component ratio (mass ratio) of "styrene / butadiene / olefin" is 67 / 4 / 29.

[0099] [Examples 1-35, Comparative Examples 1-5] Manufacturing of raw material sheet "MMA-1" As the main raw materials, 80 parts by mass of styrene-methacrylic acid copolymer (product name "T080", manufactured by Toyo Styrene Co., Ltd.) and 20 parts by mass of high-impact polystyrene resin (product name "H8117", manufactured by PS Japan Co., Ltd.) were uniformly mixed. In addition, 1.0 part by mass of talc masterbatch (product name "DSM1401A", manufactured by Toyo Styrene Co., Ltd.) was added as a foam regulator to a tandem extruder, mixed, melted, and kneaded. Three parts by mass of butane gas (isobutane) was injected under pressure at a predetermined position into the molten material and kneaded. After that, the cylindrical foam was extruded from a circular die, cooled on a predetermined mandrel, cut and molded into a sheet, and a raw material sheet (foamed sheet) with a single-layer structure of heat-resistant foam was obtained and wound up. The thickness of the obtained raw material sheet was 1.80 mm and the basis weight was 180 g / m². 2 The apparent density is 0.100 g / cm³. 3 That was the case.

[0100] Manufacturing of raw material sheet "MMA-2" As the main raw materials, 80 parts by mass of styrene-methacrylic acid copolymer (product name "G9001", manufactured by PS Japan Co., Ltd.) and 20 parts by mass of high-impact polystyrene resin (product name "H8117", manufactured by PS Japan Co., Ltd.) were uniformly mixed. Additionally, 1.0 part by mass of talc masterbatch (product name "DSM1401A", manufactured by Toyo Styrene Co., Ltd.) was added as a foam regulator to a tandem extruder, where the mixture was mixed, melted, and kneaded. Three parts by mass of butane gas (isobutane) was injected under pressure at a predetermined position into the molten material and kneaded. The cylindrical foam was then extruded from a circular die, cooled on a predetermined mandrel, cut, and formed into a sheet. A raw material sheet (foamed sheet) with a single-layer structure of heat-resistant foam was obtained and wound up. The resulting raw material sheet had a thickness of 1.80 mm and a basis weight of 180 g / m². 2 The apparent density is 0.100 g / cm³. 3 That was the case.

[0101] Manufacturing of raw material sheet "MMA-3" As the base polymer for the first foam layer (heat-resistant foam layer), 80 parts by mass of styrene-methacrylic acid copolymer (product name "G9001", manufactured by PS Japan Co., Ltd.) and 20 parts by mass of high-impact polystyrene resin (product name "H8117", manufactured by PS Japan Co., Ltd.) were uniformly mixed, and 1.0 part by mass of talc masterbatch (product name "DSM1401A", manufactured by Toyo Styrene Co., Ltd.) was added as a foam regulator to a tandem extruder, where the mixture was mixed, melted, and kneaded. 3 parts by mass of butane gas (isobutane) was injected under pressure into the molten material at a predetermined position, kneaded, and then supplied to a merger mold. Meanwhile, in a separate tandem extruder, the material for forming the second foam layer (non-heat-resistant foam layer) was melted and kneaded, and then supplied to the aforementioned merging mold. As the material for forming the second foam layer, 95 parts by mass of polystyrene resin (product name "HRM12", manufactured by Toyo Styrene Co., Ltd.) and 5 parts by mass of high-impact polystyrene resin (product name "E641N", manufactured by Toyo Styrene Co., Ltd.) were uniformly mixed as the base polymer, and 1.0 part by mass of talc masterbatch (product name "DSM1401A", manufactured by Toyo Styrene Co., Ltd.) was added as a foam regulator to a tandem extruder, where it was mixed, melted, and kneaded. 3 parts by mass of butane gas (isobutane) was injected under pressure into this molten material at a predetermined position, kneaded, and then supplied to a merger mold. At this time, the amount (mass) supplied to the merging mold for the first foam layer and the second foam layer was adjusted to be equal. After the two types of molten mixtures supplied to the merging mold were merged and laminated within the mold, the cylindrical foam was extruded from the circular die, cooled on a predetermined mandrel, cut and formed into a sheet, and a raw material sheet (foamed sheet) having a laminated structure of a heat-resistant foam layer and a non-heat-resistant foam layer was obtained and wound up. The obtained raw material sheet had a thickness of 1.75 mm and a basis weight of 180 g / m². 2 The apparent density is 0.103 g / cm³. 3 That was the case.

[0102] Manufacturing of raw material sheet "PPE-1" As the main raw materials, 30 parts by mass of polyphenylene ether resin (product name "Noryl EFN4230", manufactured by Sabic Co., Ltd.) and 70 parts by mass of high-impact polystyrene resin (product name "H8117", manufactured by PS Japan Co., Ltd.) were uniformly mixed. Additionally, 1.0 part by mass of talc masterbatch (product name "DSM1401A", manufactured by Toyo Styrene Co., Ltd.) was added as a foam regulator to a tandem extruder, where the mixture was mixed, melted, and kneaded. 4 parts by mass of butane gas (isobutane) was injected under pressure at a predetermined position into the molten material and kneaded. The cylindrical foam was then extruded from a circular die, cooled on a predetermined mandrel, cut, and formed into a sheet. A raw material sheet (foamed sheet) with a single-layer structure of heat-resistant foam was obtained and wound up. The resulting raw material sheet had a thickness of 1.65 mm and a basis weight of 140 g / m². 2 The apparent density is 0.085 g / cm³. 3 That was the case.

[0103] Manufacturing of raw material sheet "PPE-2" As the main raw materials, 39 parts by mass of polyphenylene ether resin (product name "Noryl EFN4230", manufactured by Sabic Co., Ltd.), 41 parts by mass of polystyrene resin (product name "HP555", manufactured by DIC Corporation), and 20 parts by mass of high-impact polystyrene resin (product name "E641N", manufactured by Toyo Styrene Co., Ltd.) were uniformly mixed, and 1.0 part by mass of talc masterbatch (product name "DSM1401A", manufactured by Toyo Styrene Co., Ltd.) was added as a foam regulator to a tandem extruder, which was then mixed, melted, and kneaded. Three parts by mass of butane gas (isobutane) were injected under pressure at a predetermined position into the molten material and kneaded. After that, the cylindrical foam was extruded from a circular die, cooled on a predetermined mandrel, cut and molded into a sheet, and a raw material sheet (foamed sheet) with a single-layer structure of heat-resistant foam was obtained and wound up. The resulting raw material sheet had a thickness of 1.95 mm and a basis weight of 230 g / m². 2 The apparent density is 0.118 g / cm³. 3 That was the case.

[0104] Manufacturing of raw material sheet "PPE-3" As the base polymer for the first foam layer (heat-resistant foam layer), 30 parts by mass of polyphenylene ether resin (product name "Noryl EFN4230", manufactured by Sabic Co., Ltd.) and 70 parts by mass of polystyrene resin (product name "XC515", manufactured by DIC Corporation) were uniformly mixed, and 1.0 part by mass of talc masterbatch (product name "DSM1401A", manufactured by Toyo Styrene Co., Ltd.) was added as a foam regulator to a tandem extruder, where the mixture was mixed, melted, and kneaded. 5 parts by mass of butane gas (isobutane) was injected under pressure at a predetermined position into this molten material, kneaded, and then supplied to a merger mold. Meanwhile, in a separate tandem extruder, the material for forming the second foam layer (non-heat-resistant foam layer) was melted and kneaded, and then supplied to the aforementioned merging mold. As the material for forming the second foam layer, 10 parts by mass of polyphenylene ether resin (product name "Noryl EFN4230", manufactured by Sabic Co., Ltd.) and 90 parts by mass of polystyrene resin (product name "HP555", manufactured by DIC Corporation) were uniformly mixed as the base polymer, and 1.0 part by mass of talc masterbatch (product name "DSM1401A", manufactured by Toyo Styrene Co., Ltd.) was added as a foam regulator to a tandem extruder, which was then mixed, melted, and kneaded. 4 parts by mass of butane gas (isobutane) was injected under pressure into the molten material at a predetermined position, kneaded, and then supplied to a merger mold. At this time, the amount (mass) supplied to the merging mold for the first foam layer and the second foam layer was adjusted to be equal. After the two types of molten mixtures supplied to the merging mold were merged and laminated within the mold, the cylindrical foam was extruded from the circular die, cooled on a predetermined mandrel, cut and formed into a sheet, and a raw material sheet (foamed sheet) having a laminated structure of a heat-resistant foam layer and a non-heat-resistant foam layer was obtained and wound up. The obtained raw material sheet had a thickness of 1.60 mm and a basis weight of 110 g / m². 2 The apparent density is 0.069 g / cm³. 3 That was the case.

[0105] Manufacturing of raw material sheets "PS series" 100 parts by mass of polystyrene resin (product name "G0002", manufactured by PS Japan Co., Ltd.) with a melt mass flow rate (MFR) of 1.8 g / 10 min as the main raw material, and 1.0 part by mass of talc masterbatch (product name "DSM1401A", manufactured by Toyo Styrene Co., Ltd.) as a foam regulator were placed in a tandem extruder, mixed, melted, and kneaded. 3.3 parts by mass of butane gas (isobutane) were injected under pressure into the molten material at a predetermined position and kneaded. After extruding the cylindrical foam from a circular die with a diameter of φ170 mm, it was cooled on a predetermined mandrel, cut and molded into a sheet, and a raw material sheet (foamed sheet) with a single-layer structure of non-heat-resistant foam was obtained and wound up. The thickness of the obtained raw material sheet was 1.75 mm and the basis weight was 220 g / m². 2 The apparent density is 0.126 g / cm³. 3 That was the case.

[0106] <Mixing of resin compositions for non-foamed resin layers> Polyolefin resin, polystyrene resin (high-impact polystyrene resin, general-purpose polystyrene resin), and a compatibilizer were blended in the proportions shown in Tables 1-8 and pre-mixed in a mixing drum.

[0107] Manufacturing of laminated foam sheets On one side of the raw material sheet obtained in the above steps "Manufacturing of Raw Material Sheet 'MMA-1'" to "Manufacturing of Raw Material Sheet 'PS-type'", the resin composition premixed in the above step "Mixing of Resin Composition for Non-Foaming Resin Layer" is extruded in an extruder (T-die) with a basis weight of 120 g / m². 2 The material was adjusted and extruded, then laminated using a T-die method at a take-up speed of 13 m / min to obtain a laminated foamed sheet. For example, when the raw material sheet is "MMA-1", the thickness of the obtained laminated foamed sheet is 1.89 mm (thickness of the non-foamed resin layer is 120 μm, thickness of the foamed sheet is 1.77 mm), and the basis weight is 300 g / m². 2 The apparent density is 0.159 g / cm³. 3 That was the case.

[0108] <Lamination of thermoplastic resin film layers> A 50 μm thick CPPS dry laminate film (a dry laminate film made by laminating a 30 μm thick unoriented polypropylene film and a 20 μm thick unoriented polystyrene film with an adhesive layer in between) was laminated to the surface (outermost surface) of the non-foamed resin layer of the laminated foam sheet obtained above, using a heat-pressing method so that the unoriented polystyrene film side was adhered to the surface of the non-foamed resin layer. In addition, a 20 μm thick CPS film (unoriented polystyrene film) with a printed pattern was laminated to the surface of the foam sheet (foam layer) of the laminated foam sheet obtained above, using a heat-pressing method. In this way, a laminated foam sheet having thermoplastic resin film layers on both the surface of the non-foamed resin layer and the surface of the foam sheet (foam layer) was obtained. The thickness of the obtained laminated foam sheet was 1.91 mm (thickness of CPPS dry laminate film: 50 μm, thickness of non-foamed resin layer: 120 μm, thickness of foam sheet: 1.72 mm, thickness of CPS film: 20 μm), and the basis weight was 407 g / m². 2 The apparent density is 0.212 g / cm³.3 That was the case.

[0109] Manufacturing of foamed containers Each laminated foam sheet was left at 27±3°C and 60±5% relative humidity for 24 hours. After that, a rectangular test specimen measuring 700mm in length and 1040mm in width was cut from the laminated foam sheet. Next, a single-shot molding machine (manufactured by Tosei Sangyo Co., Ltd., product name "FM-3A") was used. The average temperature of the upper heater of this single-shot molding machine was set to 270°C, the average temperature of the lower heater was set to 220°C, and the ambient temperature was set to 155°C. Next, the above test specimens were introduced into the single-shot molding machine and heated for 15 seconds, after which 18 foamed containers with an opening at the top were produced for each example by thermoforming. The foamed containers of Examples 1-28, 31-35, and Comparative Examples 1-5 had a non-foamed resin layer on the inner surface of the container, while the foamed containers of Examples 29 and 30 had a non-foamed resin layer on the outer surface of the container. The resulting foamed containers were circular, bowl-shaped containers in plan view (opening diameter 190 mm, bottom diameter 170 mm, height 50 mm).

[0110] The physical properties of the obtained laminated foam sheet, the non-foamed resin layer, the heat-resistant foam layer, and the foam container were measured and evaluated using the following methods. The results are shown in Tables 1 to 8. In the tables, "-" in the non-foamed resin layer composition column indicates that the component is not present. In the non-foamed resin layer physical properties column, "-" indicates that the item was not measured. In the evaluation column, "-" indicates that the item was not evaluated.

[0111] ≪Proportion of each component in the mixed resin (ratio of 3 components)≫ From the obtained laminated foam sheet, sections of the non-foamed resin layer were cut using a slicer or razor, and approximately 0.1 to 0.5 mg of the sample was accurately weighed. The sample was wrapped in a ferromagnetic metal body, "Pyrofoil," manufactured by Nippon Analytical Engineering Co., Ltd., with a Curie point of 590°C, to prepare a test specimen. The test specimen was prepared so that the ferromagnetic metal body was pressed against the sample, and the test specimen was heated in a "JPS-700" Curie point pyrolizer, manufactured by Nippon Analytical Engineering Co., Ltd., to decompose the sample.

[0112] <Ratio of styrene component> The styrene monomer generated by decomposition was measured using an "Agilent Technologies GC7820" gas chromatograph (detector = FID), and the peak area of the styrene monomer was determined. For the peak area of the styrene monomer, the ratio of the styrene component contained in the sample was calculated from a calibration curve prepared in advance. The standard sample for preparing the calibration curve used suspension-polymerized PS fine particles manufactured by Sekisui Chemical Co., Ltd.

[0113] <Ratio of butadiene component> The butadiene monomer and 4-vinyl-1-cyclohexene monomer generated by decomposition were measured using an "Agilent Technologies GC7820" gas chromatograph (detector = FID), and the total peak area of the butadiene monomer and 4-vinyl-1-cyclohexene monomer was determined. The total of the butadiene monomer and 4-vinyl-1-cyclohexene monomer was regarded as the butadiene component. The ratio of the butadiene component contained in the sample was calculated from a calibration curve prepared in advance. The standard sample for preparing the calibration curve used a standard sample of styrene / butadiene rubber = 85 / 15 (mass ratio).

[0114] The measurement conditions of the gas chromatograph were as follows. <Measurement conditions> · Heating: 590 °C, 5 seconds. · Oven temperature: 300 °C. · Needle temperature: 300 °C. · Column: "DB-5" manufactured by Agilent Technologies (film thickness 0.25 μm × inner diameter 0.25 mm × length 30 m).

[0115] <GC oven temperature rising conditions> · Initial temperature: 50 °C (held for 0.5 minutes). · First-stage temperature rising rate: 10 °C / min (up to 200 °C, holding time 0 minutes). · Second-stage temperature rising rate: 20 °C / min (up to 320 °C). · Final temperature: 320 °C (held for 0.5 minutes). Carrier gas: He gas. ·He flow rate: 25mL / min. • Inlet pressure: 100kPa. Column inlet pressure: 100kPa. ·Inlet temperature: 300℃. Detector temperature: 300℃. Split ratio: 1 / 50.

[0116] <Percentage of olefin components> In the case where the main components of the non-foamed resin layer are a three-component system consisting of styrene, butadiene, and ethylene, the proportion of olefin (ethylene) components was calculated using the following formula (2). [Ethylene content (mass%)] = 100 - [Styrene content measured by gas chromatography (mass%)] - [Butadiene content measured by gas chromatography (mass%)] ... (2)

[0117] Furthermore, it was confirmed that the main components of the non-foamed resin layer are a three-component system consisting of styrene, butadiene, and ethylene by measuring the infrared absorption spectrum using the following measuring device and conditions. <Measurement device and measurement conditions> • Measurement equipment: Thermo SCIENTIFIC "Nicolet iS10" Fourier transform infrared spectrophotometer and Thermo SCIENTIFIC Smart-iTR single-reflection horizontal ATR. ATR Crystal: Diamond-attached KRS-5 (angle = 45°). ·Measurement method: Single reflection ATR method. ·Measurement wavenumber range: 4000cm -1 ~400cm -1 . • Wavenumber dependence of measurement depth: Uncorrected • Detectors: Deuterated triglycine sulfate (DTGS) detector and KBr beam splitter. ·Resolution: 4cm -1 . • Number of cumulative measurements: 16 (same for background measurements). • Number of tests: n=3 measurements, and the average value was used.

[0118] If the main components in the non-foamed resin layer are a four-component system or higher, by preparing a calibration curve in advance for standard samples with ethylene / styrene in a predetermined mass ratio (for example, three points with ratios of 25 / 50, 50 / 50, and 75 / 50), the ethylene / styrene component ratio in the mixed resin can be calculated from the infrared absorption spectrum obtained from the measurement of the mixed resin, and the proportion of the olefin component (ethylene component) can be calculated using the following formula (3). [Ethylene content (mass%)] = [Styrene content (mass%) measured by gas chromatography] × [Ethylene / styrene ratio calculated by infrared absorption spectroscopy] ... (3)

[0119] ≪Melting point (Tm), crystallization temperature (Tc), supercooling temperature difference (Tm-Tc)≫ The melting point (Tm) and crystallization temperature (peak temperature of the crystallization peak (Tc)) of the mixed resin in the non-foamed resin layer were measured in accordance with the methods described in JIS K7121:1987 and JIS K7121:2012 "Method for Measuring Transition Temperature of Plastics". However, the sampling method and temperature conditions were as follows. The non-foamed resin layer was collected from the laminated foam sheet using a slicer or razor, and cut into a rectangular shape measuring 10 mm vertically and 5 mm horizontally to serve as the sample. The sample was placed in the bottom of an aluminum measuring container, cut to an appropriate size to ensure there were no gaps, and filled with 5.5 ± 0.5 mg of the sample. The aluminum lid was then placed over the container. Next, differential scanning calorimetry (DSC) analysis was performed using a Hitachi High-Tech Science Corporation "DSC7000X, AS-3" differential scanning calorimetry (DSC) instrument. In the DSC measurement, the sample was heated and cooled in the following steps under a nitrogen gas flow rate of 20 mL / min to obtain the DSC curve. (Step 1) Cool the temperature from 30°C to -40°C and hold for 10 minutes. (Step 2) Increase the temperature from -40°C to 220°C (first heating step), and hold for 10 minutes. (Step 3) Cool down from 220°C to -40°C and hold for 10 minutes. (Step 4) Increase the temperature from -40°C to 220°C (second heating). All heating and cooling were performed at a rate of 10°C / min. Alumina was used as the reference material.

[0120] Using the analysis software included with the DSC instrument, the temperature at the top of the crystallization peak observed during the cooling process (step 3) was read and defined as the crystallization temperature (Tc), and the temperature at the top of the melting peak observed during the second heating process (step 4) was read and defined as the melting temperature (melting point (Tm)). The supercooling temperature difference (Tm-Tc) was calculated using the following equation (4). [Supercooling temperature difference (Tm-Tc) (°C)] = [Melting point (Tm) (°C)] - [Crystallization temperature (Tc) (°C)] ... (4)

[0121] Figure 3 shows the DSC curve of the sample taken from the laminated foam sheet of Example 1. As shown in Figure 3, curve P is the DSC curve of the second heating process (step 4). The temperature at the top of the melting peak of curve P, 131.1°C, is the melting point (Tm) of the mixed resin. Curve Q is the DSC curve for the cooling process (step 3). The temperature at the top of the crystallization peak of curve Q, 119.7°C, is the crystallization temperature (Tc) of the mixed resin. The supercooling temperature difference (Tm-Tc) of the mixed resin is given by equation (4) as 131.1-119.7=11.4℃.

[0122] ≪Melting Tension≫ The melt tension of the non-foamed resin layer was measured using a Rheologic 5000T twin-bore capillary rheometer manufactured by Chiast. The melt tension was measured using a tension-sensing pulley located 27 cm below a capillary die with a diameter of 2.095 mm, a length of 8 mm, and an inlet angle of 90 degrees (conical), which was set in the above measuring device. First, the sample was filled into a 15 mm diameter barrel heated to a test temperature of 200 °C. The filled sample was preheated and melted for 5 minutes. The molten material was extruded from the capillary die in a string-like manner while maintaining a constant piston descent speed (0.07730 mm / s). This string-like material was passed through a tension-sensing pulley and then wound up using a winding roll. The initial winding speed was 4 mm / s. The winding speed was 12 mm / s. 2 The tension was gradually increased. The average of the maximum and minimum tension values ​​immediately before the point where the string-like material broke was defined as the melt tension (MT) of the sample.

[0123] ≪Softening temperature≫ The softening temperature of the mixed resin was measured using the EXSTRAR TMA / SS6100 thermal, stress, and strain (TMA) measuring device manufactured by SII Nanotechnology Co., Ltd., in accordance with the method described in JIS K7196:1991 "Test method for softening temperature of thermoplastic plastic films and sheets by thermomechanical analysis". However, the sampling method and temperature conditions were as follows. First, the non-foamed resin layer was taken from the laminated foam sheet using a slicer or razor, and several square pieces measuring 25 mm in length and 25 mm in width were prepared. These were then heat-pressed at 180°C for 5 minutes to create disc-shaped test specimens with a thickness of 1 mm and a diameter of 10 mm. The thickness of the test specimens was measured before measurement by applying an indenter (needle) with a load of 500 mN to the specimen. The measurement conditions were as follows.

[0124] <Measurement conditions> • Mode: Needle penetration test mode (quartz probe tip φ1mm). • Atmosphere: Nitrogen atmosphere. Load: 500mN. • Heating rate: 5°C / min. ·Measurement temperature: 30℃~200℃.

[0125] The TMA curves obtained from TMA measurements were analyzed using the analysis software provided with the instrument. The TMA curves were corrected using the quartz coefficient setting in the analysis software. Figure 4 shows an example of a TMA curve obtained from TMA measurement of a mixed resin. As shown in Figure 4, curve R represents the depth of insertion with respect to temperature. The linear portion of the TMA curve observed on the temperature side before the indenter (needle) begins to insert was extended towards the high-temperature side, and this line was set as the baseline L1. The tangent line L2 at the point where the insertion speed is maximum was extended towards the low-temperature side, and the intersection point S with baseline L1 was found. The temperature at intersection point S was defined as the insertion temperature, and this insertion temperature was defined as the softening temperature of the mixed resin.

[0126] ≪Resin density of mixed resins≫ The resin density of the mixed resin was determined by the following method. From the laminated foam sheet, the non-foamed resin layer was taken using a slicer or razor, and 30 rectangular pieces measuring 100 mm in length and 25 mm in width were prepared as test specimens. The volume (cm³) of these test specimens was measured using the 1-1 / 2-1 atmosphere method with a Tokyo Science Co., Ltd. "1000" air-comparison hydrometer. 3 The specific gravity was determined. The test specimens were pre-conditioned for 16 hours under the environment of symbol 23 / 50, Class 2, as described in JIS K7100:1999 "Plastics - Standard atmospheres for conditioning and testing," and used for measurement. The measurement was carried out under the same environment. The air-comparative hydrometer used a standard sphere (large 28.96 cm). 3 , small 8.58cm 3 The correction was made using the following formula: Resin density of the mixed resin (g / cm³). 3 ) was calculated using the following formula (5). [Resin density (g / cm 3 )] = [Mass of the test specimen (g)] / [Measured volume (cm³) using an air-comparative hydrometer] 3 )] ···(5)

[0127] ≪Glass transition temperature (Tg)≫ The glass transition temperature (Tg) of the resin constituting the heat-resistant foam layer was measured as follows. (Pre-processing) Prior to measuring the glass transition temperature (Tg), 5-6 g of the heat-resistant foam layer was weighed using a balance, sandwiched between two polytetrafluoroethylene sheets, and pressed to remove air bubbles as described below. • Pressing device: "Lab Press 10T", a small pressing device manufactured by Toyo Seiki Seisakusho Co., Ltd. Temperature: Upper heater 180°C, lower heater 180°C. • Pressing process: Pressing was performed at "0.54 MPa for 3 minutes," followed by 5 cycles of pressing at "0.54 MPa for 2 seconds" and "pressure release for 2 seconds" as one cycle, and then pressing at "15.5 MPa for 2 minutes." (Measurement of glass transition temperature (Tg)) The glass transition temperature (Tg) of the sample degassed as described above was measured in accordance with the method described in JIS K7121:1987 and JIS K7121:2012 "Method for Measuring the Transition Temperature of Plastics". However, the sampling method and temperature conditions were as follows: 5.5 ± 0.5 mg of the sample was packed into the bottom of an aluminum measuring container without any gaps, and then an aluminum lid was placed over it. Differential scanning calorimetry was then performed using a Hitachi High-Tech Science Corporation "DSC7000X, AS-3" differential scanning calorimeter. The sample was heated and cooled in the following steps under a nitrogen gas flow rate of 20 mL / min to obtain a DSC curve. (Step 1) Heat from 30°C to 200°C at a rate of 20°C / min and hold for 10 minutes. (Step 2) Quickly remove the sample and allow it to cool in an environment of 25±10℃. (Step 3) Heat from 30°C to 200°C at a rate of 20°C / min. From the obtained DSC curve, the intermediate glass transition temperature observed during the second heating process (step 3) was calculated using the analysis software provided with the instrument. Alumina was used as the reference material in this calculation. This intermediate glass transition temperature was determined from the above-mentioned JIS standard (section 9.3).

[0128] <<Suppression of drawdown and moldability>> The left-hand side of equation (I) below was calculated from the softening temperature (TS) of the mixed resin and the glass transition temperature (Tg) of the resin constituting the heat-resistant foam layer, and the suppression of drawdown and moldability were evaluated based on the evaluation criteria below. [TS-(Tg-26)]≧0(℃) ···(I) Evaluation Criteria A: The value on the left side of equation (I) is 0 or greater. D: The value on the left side of equation (I) is less than 0.

[0129] (Evaluation method) <<Peel Strength>> The non-foamed resin layer of the laminated foamed sheet obtained in each example was peeled off by hand, and the peel strength was evaluated based on the evaluation criteria below. 《Notation Standards》 A: The peel strength is sufficiently strong, and the non-foamed resin layer cannot be peeled off by hand. B: When the non-foamed resin layer is peeled off, the foamed sheet is bonded so strongly that it causes material damage. C: When the non-foamed resin layer is peeled off, there is almost no material damage to the foamed sheet. D: The edges of the non-foamed resin layer are lifted and can be peeled off with minimal force.

[0130] ≪Container impact resistance≫ 400g of water was placed in the foamed containers obtained in each example, and the openings were sealed. These containers were dropped onto a concrete surface from a height of 1.0m in a 23°C environment, and the presence or absence of damage to the containers was visually inspected. Tests were conducted on 10 foamed containers from each example, and the impact resistance of the containers was evaluated based on the evaluation criteria below. Note that for Comparative Example 4, it was not possible to mold a foamed container, so the impact resistance of the container was not evaluated. Evaluation Criteria A: The number of damaged containers is 0 to 2. B: The number of damaged containers is 3 to 5. C: The number of damaged containers is between 6 and 9. D: The number of damaged containers is 10.

[0131] <<Drawdown during molding>> The test pieces cut out in the above-mentioned "Manufacturing of Foamed Containers" were introduced into a single-shot molding machine and heated at an ambient temperature of 155°C for 15 seconds. Immediately after removing the test pieces without further molding, the sheet shape of the test pieces was visually observed, and the drawdown during molding was evaluated based on the evaluation criteria below. Evaluation Criteria A: I haven't experienced any drawdowns at all. B: Slight drawdown is observed inside the molding machine, but no drawdown occurs after removal. C: There is a slight drawdown. D: It's clearly a drawdown.

[0132] <<Elongation during molding>> The foamed containers obtained in each example were visually observed, and the elongation during molding was evaluated based on the following evaluation criteria. A greater elongation during molding indicates better moldability. Evaluation Criteria A: All 18 pieces were perfectly molded. B: In some of the 18 containers, variations in whiteness were observed on the inner surface of the container due to poor expansion of the non-foamed resin layer. C: Variations in whiteness were observed on the inner surface of all 18 containers due to poor expansion of the non-foamed resin layer. D: Some of the 18 containers showed signs of cracking or wrinkling.

[0133] ≪Container Strength≫ The opening of the foamed container obtained in each example was held by hand, and the container strength was evaluated based on the evaluation criteria below. Note that in Comparative Example 4, the foamed container could not be molded, so the container strength was not evaluated. Evaluation Criteria A: When you hold the opening with your hand and pull it outwards, it has sufficient strength. B: When you hold the opening with your hand and pull it outwards, it has adequate strength. C: When holding the opening with your hand and pulling it outwards, it feels weak. D: When the opening is facing downwards and the bottom surface is pressed down from above, the side walls buckle easily.

[0134] ≪Heat resistance of the container≫ In each example, 100 mL of salad oil was placed in the resulting foamed container, and it was microwaved in a commercial microwave oven at 1500 W for 70 seconds. After wiping off the salad oil, the surface condition was observed. The degree of collapse of the irregularities on the container was visually observed, and the heat resistance of the container was evaluated based on the evaluation criteria below. In Comparative Example 4, it was not possible to mold a foamed container, so the heat resistance of the container was not evaluated. Evaluation Criteria A: The uneven surface of the container remains. B: Some of the unevenness on the container is missing. C: The container still has some slight unevenness. D: The uneven surface of the container has disappeared.

[0135] ≪Overall Rating≫ The above six items (peel strength, container impact resistance, drawdown during molding, elongation during molding, container strength, and container heat resistance) were comprehensively evaluated based on the following evaluation criteria. Evaluation Criteria A: Of the six items listed above, all items received an "A" rating, or all items received an "A" or "B" rating, with one item receiving a "B". B: Of the six items listed above, all items received an evaluation of "A," "B," or "C," with two or more items receiving "B" or one item receiving "C." C: Of the six items listed above, all items received an evaluation of "A," "B," or "C," with two items receiving a "C." D: Of the above six items, there was a "C" or "D" in the item evaluation, and there were three or more "C"s or one or more "D"s.

[0136] (Lamination processability evaluation) In addition to the overall evaluation described above, a lamination processability evaluation was conducted for each example of the non-foamed resin layer to confirm its moldability and productivity. The following evaluations were performed for the lamination processability evaluation.

[0137] ≪Collection Stability≫ The extruder's discharge rate was adjusted so that the thickness of the non-foamed resin layer was 120 μm. Next, the take-up speed of the take-up machine was adjusted to a predetermined speed, and a length of 3 m in the extrusion direction (MD direction) was taken up. The variation in the thickness of the non-foamed resin layer during extrusion lamination was checked using a scanning electron microscope (Hitachi High-Tech Corporation, SU1510). A variation in thickness was defined as "variation present" if the thickness of the taken-up non-foamed resin layer was ±30 μm or more from 120 μm. Take-up stability was evaluated based on the following evaluation criteria. The faster the take-up speed at which the thickness of the non-foamed resin layer becomes "variable," the better the take-up stability. Evaluation Criteria A: With a pickup speed of 26 m / min, there was no variation in thickness. B: At a pull-out speed of 26 m / min, there is variation in thickness, but at a pull-out speed of 23 m / min, there is no variation in thickness. C: At a pull-out speed of 23 m / min, there is variation in thickness, but at a pull-out speed of 20 m / min, there is no variation in thickness. D: At a pull-out speed of 20 m / min, there is variation in thickness, but at a pull-out speed of 16 m / min, there is no variation in thickness. E: At a pull-out speed of 16 m / min, there is variation in thickness, but at a pull-out speed of 13 m / min, there is no variation in thickness.

[0138] ≪Neck-in≫ The cross-sections of the laminated foam sheets obtained in each example were cut in the thickness direction along the width direction (TD direction) and observed with a scanning electron microscope (Hitachi High-Tech Corporation, SU1510) to identify the locations where the thickness of the non-foamed resin layer was 150 μm or more. The presence or absence of the neck-in phenomenon was evaluated based on the following evaluation criteria. The closer the location where the thickness of the non-foamed resin layer is 150 μm or more is to the edge in the width direction, the more effectively the neck-in phenomenon was suppressed. Evaluation Criteria A: The location where the thickness is 150 μm or more is within 5 cm from the edge in the width direction. B: The location where the thickness is 150 μm or more is between 5 cm and 10 cm from the edge in the width direction. C: The location where the thickness is 150 μm or more is more than 10 cm from the edge in the width direction, closer to the center.

[0139]

Table 1

[0140]

Table 2

[0141]

Table 3

[0142]

Table 4

[0143]

Table 5

[0144]

Table 6

[0145] ]>

Table 7

[0146]

Table 8

[0147] ]>As shown in Tables 1 to 8, for Examples 1 to 35 to which the present invention was applied, the comprehensive evaluation was “A”, “B” or “C”. In contrast, Comparative Example 1, which did not contain polyolefin resin in the non-foamed resin layer, had a drawdown of "D" during molding and an overall evaluation of "D". Comparative Example 2, in which the content of butadiene and olefin components was outside the scope of the present invention, had a peel strength of "D" and an overall evaluation of "D". Comparative Example 3, in which the content of butadiene component was outside the scope of the present invention, had three items evaluated as "C" and an overall evaluation of "D". Comparative Example 4, in which the content of butadiene component was outside the scope of the present invention, had an elongation of "D" during molding and could not form a foamed container. Comparative Example 5, in which the glass transition temperature (Tg) of the resin constituting the heat-resistant foamed layer was outside the scope of the present invention, had a heat resistance of "D" for the container and an overall evaluation of "D".

[0148] From the above results, it was confirmed that by applying the present invention, excellent peel strength, container strength, heat resistance, and impact resistance can be achieved, drawdown during molding can be suppressed, and moldability and productivity can be further improved. [Explanation of symbols]

[0149] 1. Polystyrene resin laminated foam sheet 10 Polystyrene foam sheet 11 Surface of polystyrene foam sheet 20 Non-foamed resin layer 21 Surface of the non-foamed resin layer 30 Interface between polystyrene foam sheet and non-foamed resin layer

Claims

1. A non-foamed resin layer is laminated on one or both sides of a polystyrene foam sheet. The aforementioned polystyrene-based foamed sheet includes a heat-resistant foamed layer. The glass transition temperature (Tg) of the resin constituting the heat-resistant foam layer is 110°C or higher. The non-foamed resin layer comprises a mixed resin containing a polystyrene resin and a polyolefin resin. The mixed resin includes a high-impact polystyrene resin having butadiene units, and in the mixed resin, the mass ratio of the high-impact polystyrene resin to the polyolefin resin (high-impact polystyrene resin: polyolefin resin) is 45:55 to 99.9:0.

1. The styrene content in the mixed resin is 27 to 95% by mass relative to the total mass of the mixed resin. The content of the butadiene component in the mixed resin is 2.2 to 12% by mass relative to the total mass of the mixed resin. A polystyrene resin laminated foam sheet, wherein the content of the olefin component in the mixed resin is 0.1 to 70% by mass relative to the total mass of the mixed resin.

2. The polystyrene resin laminated foam sheet according to claim 1, wherein the polyolefin resin in the mixed resin is a polyethylene resin.

3. The polystyrene resin laminated foam sheet according to claim 1 or 2, wherein the softening temperature (TS) of the mixed resin and the glass transition temperature (Tg) satisfy the relationship expressed by the following formula (I). [TS-(Tg-26)]≧0(℃)...(I)

4. The mixed resin has a crystallization peak, and the peak temperature of the crystallization peak is 90 to 140°C. The polystyrene resin laminated foam sheet according to claim 1 or 2, wherein the temperature difference between the melting point of the mixed resin and the peak temperature is 1 to 20°C.

5. The polystyrene resin laminated foam sheet according to claim 1 or 2, wherein the polyolefin resin comprises high-density polyethylene and low-density polyethylene.

6. The polystyrene resin laminated foam sheet according to claim 5, wherein the mass ratio of the high-density polyethylene to the low-density polyethylene (high-density polyethylene:low-density polyethylene) is 10:90 to 90:

10.

7. The polystyrene resin laminated foam sheet according to claim 1 or 2, wherein the polyolefin resin in the mixed resin is a plant-derived resin.

8. The polystyrene resin laminated foam sheet according to claim 1 or 2, wherein a thermoplastic resin film layer is located on at least one surface of one or both surfaces of the polystyrene resin foam sheet and one or both surfaces of the non-foamed resin layer.

9. The heat-resistant foamed layer comprises at least one selected from the group consisting of styrene-acrylic acid copolymer, styrene-methacrylic acid copolymer, and polyphenylene ether resin, as described in claim 1 or 2.

10. A method for producing a polystyrene resin laminated foam sheet according to claim 1 or 2, A method for manufacturing a polystyrene resin laminated foam sheet, comprising a lamination step of extruding and laminating a resin composition containing the mixed resin onto one or both sides of the polystyrene resin foam sheet.

11. A non-foamed resin layer is laminated on one or both sides of a polystyrene foam sheet. The aforementioned polystyrene-based foamed sheet includes a heat-resistant foamed layer. The glass transition temperature (Tg) of the resin constituting the heat-resistant foam layer is 110°C or higher. The non-foamed resin layer comprises a mixed resin containing a polystyrene resin and a polyolefin resin. The mixed resin includes a high-impact polystyrene resin having butadiene units, and in the mixed resin, the mass ratio of the high-impact polystyrene resin to the polyolefin resin (high-impact polystyrene resin: polyolefin resin) is 45:55 to 99.9:0.

1. The styrene content in the mixed resin is 27 to 95% by mass relative to the total mass of the mixed resin. The content of the butadiene component in the mixed resin is 2.2 to 12% by mass relative to the total mass of the mixed resin. A polystyrene resin laminated foam container, wherein the content of the olefin component in the mixed resin is 0.1 to 70% by mass relative to the total mass of the mixed resin.

12. The polystyrene resin laminated foam container according to claim 11, wherein the polyolefin resin in the mixed resin is a polyethylene resin.

13. The polystyrene resin laminated foam container according to claim 11 or 12, wherein the softening temperature (TS) of the mixed resin and the glass transition temperature (Tg) satisfy the relationship expressed by the following formula (I). [TS-(Tg-26)]≧0(℃)...(I)

14. The mixed resin has a crystallization peak, and the peak temperature of the crystallization peak is 90 to 140°C. The polystyrene resin laminated foam container according to claim 11 or 12, wherein the temperature difference between the melting point of the mixed resin and the peak temperature is 1 to 20°C.

15. The polystyrene resin laminated foam container according to claim 11 or 12, wherein the polyolefin resin comprises high-density polyethylene and low-density polyethylene.

16. The polystyrene resin laminated foam container according to claim 15, wherein the mass ratio of the high-density polyethylene to the low-density polyethylene (high-density polyethylene:low-density polyethylene) is 10:90 to 90:

10.

17. The polystyrene resin laminated foam container according to claim 11 or 12, wherein the polyolefin resin in the mixed resin is a plant-derived resin.

18. The polystyrene resin laminated foam container according to claim 11 or 12, wherein a thermoplastic resin film layer is located on at least one surface of one or both sides of the polystyrene resin foam sheet and one or both sides of the non-foamed resin layer.

19. The polystyrene resin laminated foam container according to claim 11 or 12, wherein the heat-resistant foam layer comprises at least one selected from the group consisting of styrene-acrylic acid copolymer, styrene-methacrylic acid copolymer, and polyphenylene ether resin.

20. A method for manufacturing a polystyrene resin laminated foam container according to claim 11 or 12, A lamination step of extruding and laminating a resin composition containing the mixed resin onto one or both sides of the polystyrene foam sheet, A method for manufacturing a polystyrene resin laminated foam container, comprising a molding step of heating and molding the polystyrene resin laminated foam sheet obtained in the lamination step.

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