Polystyrene-based resin laminate foam sheet and polystyrene-based resin laminate foam container

Abstract

To provide a polystyrene-based resin laminate foam sheet that is hard to cause a defective appearance in thermoforming, and a polystyrene-based resin laminate foam container in which the polystyrene-based resin laminate foam sheet is thermally foamed.SOLUTION: A polystyrene-based resin laminate foam sheet according to an embodiment has a non-foamed polystyrene-based resin layer laminated on at least one side of a polystyrene-based resin foam layer. The resin foam layer is formed by foaming polystyrene-based resin (I). The total content of styrene dimers and styrene trimers in the resin foam layer is 2,000 ppm or less. The non-foamed polystyrene-based resin layer contains polystyrene-based resin (II) and rubber-modified polystyrene-based resin in a weight ratio of 10:90 to 60:40. A weight-average molecular weight (Mw) and a Z-average molecular weight (Mz) of the polystyrene-based resin (II) fall within predetermined ranges.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a laminated polystyrene resin foam sheet and a laminated polystyrene resin foam container. [Background technology]

[0002] The thermoplastic resin laminated foam sheet for molding a container is manufactured by supplying a thermoplastic resin together with a foaming agent, a bubble adjusting agent, etc., into an extruder, heating and melting these materials in the extruder, kneading them, cooling them to a predetermined temperature, extruding the resin into a sheet shape from a die, foaming it, and immediately cooling it to produce a foam sheet, and laminating a thermoplastic resin film on the surface of the foam sheet. In addition, a typical method for manufacturing a container using this thermoplastic resin laminated foam sheet is to heat a thermoplastic resin laminated foam sheet wound into a roll shape to a constant temperature in the heating zone of a molding machine, and then thermoforming it into a desired container shape in the molding zone. Among such thermoplastic resin laminated foam sheets, polystyrene resin laminated foam sheets in which a polystyrene resin foam layer and a polystyrene resin layer are laminated are used in large quantities as a container material for instant noodles in cups, etc.

[0003] The above thermoforming is carried out by a method called vacuum forming, pressure forming, vacuum pressure forming, match mold forming, press forming, or the like, and the softened polystyrene resin laminated foam sheet is instantly given the shape of the product.

[0004] In such thermoforming, since the forming process is performed at a relatively high strain rate, it may be difficult to produce a molded product with a uniform thickness and a beautiful appearance without wrinkles. For example, in the case of containers for instant noodles in a cup, the raw material sheet is subjected to a relatively deep drawing process in a short time, and therefore, during thermoforming, a defective appearance may occur due to uneven stretching of the polystyrene-based resin laminated foamed sheet. A specific example of such a defective appearance is wavy-line-shaped gloss unevenness that appears on the outer surface of a container when the polystyrene-based resin laminated foamed sheet is thermoformed so that the outer surface side of the container becomes a non-foamed layer. This wavy-line-shaped unevenness is also called "chill mark" and may impair the beauty of the resin molded product.

[0005] Polystyrene resins contain a certain amount of oligomer components, such as styrene dimer and styrene trimer, which are polymerization residues. Food containers for instant noodles and other foods are required to have a low content of these oligomer components.

[0006] However, since the plasticizing effect of styrene dimer, styrene trimer, etc. is low in low oligomer grade polystyrene resins, they are inferior in ease of deformation near their softening points compared to general polystyrene resins. When low oligomer grade polystyrene resins are used as a forming material for a polystyrene resin laminated foam sheet for forming a deep-drawn container, the above-mentioned uneven stretching causes a problem of poor appearance.

[0007] That is, when a polystyrene-based resin laminate foam sheet is formed using a low oligomer grade polystyrene-based resin, the above-mentioned problem of poor appearance due to uneven stretching occurs.

[0008] In order to solve such problems, it has been considered to use a polystyrene-based resin having a property called "strain hardening," in which the stress against deformation increases according to the strain speed during thermal melting, as a material for forming a polystyrene-based resin laminated foam sheet (Patent Document 1). This polystyrene-based resin with excellent strain hardening properties exhibits a function of suppressing uneven stretching during thermoforming, and therefore can be used as a material for forming a polystyrene-based resin laminated foam sheet for forming a deep-draw container.

[0009] However, as shown in the examples of Patent Document 1 (Tables 2 to 4), even if a polystyrene-based resin has excellent strain hardening properties, if the maximum extensional viscosity is excessively high (such as "Resin F" in Table 2), it is likely to cause appearance defects such as cracks and wrinkles during thermoforming.

[0010] Therefore, conventional polystyrene-based resin laminate foam sheets are insufficient in suppressing appearance defects during thermoforming. [Prior art documents] [Patent documents]

[0011] [Patent Document 1] JP 2007-326261 A Summary of the Invention [Problem to be solved by the invention]

[0012] The present invention has been made to solve the above-mentioned problems in the conventional art, and a main object of the present invention is to provide a polystyrene-based resin laminated foam sheet that is less likely to cause appearance defects during thermoforming, and a polystyrene-based resin laminated foam container obtained by thermoforming the polystyrene-based resin laminated foam sheet. [Means for solving the problem]

[0013] The polystyrene-based resin laminated foam sheet according to an embodiment of the present invention is A polystyrene-based resin laminated foam sheet having a non-expanded polystyrene-based resin layer laminated on at least one surface of a polystyrene-based resin foam layer, The polystyrene-based resin foam layer is formed by foaming a polystyrene-based resin (I), The total content of styrene dimer and styrene trimer in the polystyrene-based resin foam layer is 2000 ppm or less, the non-expanded polystyrene-based resin layer contains a polystyrene-based resin (II) and a rubber-modified polystyrene-based resin in a weight ratio of polystyrene-based resin (II):rubber-modified polystyrene-based resin=10:90 to 60:40; The weight average molecular weight (Mw) of the polystyrene resin (II) is 280,000 to 460,000; The polystyrene resin (II) has a Z-average molecular weight (Mz) of 500,000 to 1,200,000.

[0014] In one embodiment, the laminated polystyrene resin foam sheet according to the embodiment of the present invention has a thickness of 0.5 mm to 4.0 mm.

[0015] In one embodiment, the polystyrene-based resin laminated foam sheet according to the embodiment of the present invention has a basis weight of 200 g / m 2 ~800g / m 2 It is.

[0016] The polystyrene-based resin laminated foam container according to the embodiment of the present invention is obtained by thermoforming the polystyrene-based resin laminated foam sheet according to the embodiment of the present invention. Effect of the Invention

[0017] According to the present invention, it is possible to provide a polystyrene-based resin laminated foam sheet which is less likely to suffer from poor appearance during thermoforming, and a polystyrene-based resin laminated foam container obtained by thermoforming the polystyrene-based resin laminated foam sheet. [Brief description of the drawings]

[0018] [Figure 1]FIG. 1 is a typical schematic cross-sectional view of a laminated polystyrene resin foam sheet according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a typical schematic perspective view of a laminated polystyrene resin foam container according to an embodiment of the present invention. [Diagram 3] FIG. 3 shows (a) a longitudinal sectional view seen from the front and (b) a plan view of the laminated polystyrene resin foam containers produced in the examples and comparative examples. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] Hereinafter, embodiments of the present invention will be described, but the present invention is not limited to these embodiments.

[0020] In this specification, "(meth)acrylic" means acrylic and / or methacrylic, and "(meth)acrylate" means acrylate and / or methacrylate.

[0021] <Polystyrene resin laminated foam sheet> The polystyrene-based resin laminated foam sheet according to an embodiment of the present invention is a polystyrene-based resin laminated foam sheet in which a polystyrene-based resin layer is laminated on at least one surface of a polystyrene-based resin foam layer. The polystyrene-based resin laminated foam sheet according to one embodiment of the present invention is a polystyrene-based resin laminated foam sheet in which one surface of the polystyrene-based resin foam layer and one surface of the polystyrene-based resin layer are laminated and integrated. The polystyrene-based resin laminated foam sheet according to another embodiment of the present invention is a polystyrene-based resin laminated foam sheet in which both surfaces of the polystyrene-based resin foam layer and one surface of the polystyrene-based resin layer are laminated and integrated.

[0022] The thickness of the polystyrene-based resin laminate foam sheet according to the embodiment of the present invention may be any appropriate thickness within a range that does not impair the effects of the present invention. The thickness of the polystyrene-based resin laminate foam sheet according to the embodiment of the present invention is preferably 0.5 mm to 4.0 mm, more preferably 1.0 mm to 3.5 mm, further preferably 1.2 mm to 3.0 mm, and particularly preferably 1.5 mm to 2.5 mm.

[0023] The basis weight of the polystyrene-based resin laminated foam sheet according to the embodiment of the present invention may be any appropriate thickness within a range that does not impair the effects of the present invention. The basis weight of the polystyrene-based resin laminated foam sheet according to the embodiment of the present invention is preferably 200 g / m 2 ~800g / m 2 and more preferably 220 g / m 2 ~700g / m 2 and more preferably 250 g / m 2 ~650g / m 2 and particularly preferably 300 g / m 2 ~600g / m 2 It is.

[0024] Fig. 1 is a typical schematic cross-sectional view of a polystyrene-based resin laminated foam sheet according to an embodiment of the present invention. In Fig. 1, a polystyrene-based resin laminated foam sheet 100 according to an embodiment of the present invention has a polystyrene-based resin foam layer 10 and a polystyrene-based resin layer 20 laminated together. A surface 10a on the side of the polystyrene-based resin foam layer 10 is the side of the polystyrene-based resin foam layer 10 opposite to the polystyrene-based resin layer 20. A surface 20a on the side of the polystyrene-based resin layer 20 is the side of the polystyrene-based resin layer 20 opposite to the polystyrene-based resin foam layer 10.

[0025] <Polystyrene resin foam layer> The polystyrene-based resin foam layer is typically formed by foaming a polystyrene-based resin (I). More specifically, the polystyrene-based resin foam layer is preferably formed by heating and melting the polystyrene-based resin (I) together with various additives such as a foaming agent and a bubble regulator added as necessary in an extruder, kneading the mixture, cooling the mixture to a predetermined temperature, extruding the mixture from a die into a sheet shape and foaming the mixture, and immediately cooling the mixture.

[0026] The polystyrene resin (I) may be of only one type, or of two or more types.

[0027] As the polystyrene resin (I) forming the polystyrene resin foam layer, any suitable polystyrene resin can be adopted within the scope of not impairing the effects of the present invention. Examples of such polystyrene resin (I) include homopolymers of styrene monomers such as styrene, α-methylstyrene, vinyltoluene, ethylstyrene, i-propylstyrene, t-butylstyrene, dimethylstyrene, bromostyrene, and chlorostyrene; copolymers of the above-mentioned styrene monomers; copolymers of the above-mentioned styrene monomers and (meth)acrylic acid esters (e.g., methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, cetyl (meth)acrylate, (meth)acrylonitrile, dimethyl maleate, dimethyl fumarate, diethyl fumarate, and ethyl fumarate); copolymers of the above-mentioned styrene monomers and bifunctional monomers (e.g., divinylbenzene, alkylene glycol dimethacrylate, and the like); and the like. The styrene monomer preferably contains at least styrene. The content of styrene relative to the total amount of styrene-based monomers is preferably 50% by mass or more, more preferably 70% by mass or more, further preferably 90% by mass or more, and particularly preferably 95% by mass or more.

[0028] Examples of the polystyrene resin (I) include so-called high impact polystyrene (HIPS), such as a block copolymer having a rubber component block such as butadiene or isoprene and a styrene block, and a graft copolymer in which the rubber component block is grafted to a molecular chain made of styrene.

[0029] In one embodiment, the polystyrene resin (I) may be a composite resin of a polystyrene resin (meaning a polystyrene resin (I)) and a polyolefin resin. The content ratio of the polystyrene resin to the polyolefin resin in the composite resin (polystyrene resin / polyolefin resin: mass ratio) is preferably 50 / 50 to 90 / 10, and more preferably 60 / 40 to 85 / 15. If the content of the polystyrene resin is too low, the foamability and / or moldability may be insufficient. If the content of the polystyrene resin is too high, the impact resistance and / or flexibility may be insufficient.

[0030] As the polyolefin resin, any suitable olefin resin may be adopted as long as it does not impair the effects of the present invention. The polyolefin resin may be one type or two or more types. Specific examples of the polyolefin resin include polyethylene resins such as branched low density polyethylene, linear low density polyethylene, medium density polyethylene, high density polyethylene, ethylene-vinyl acetate copolymer, ethylene-methyl methacrylate copolymer, and crosslinked bodies of these polymers; polypropylene resins such as propylene homopolymer, propylene-vinyl acetate copolymer, ethylene-propylene random copolymer, propylene-1-butene copolymer, and ethylene-propylene-butene random copolymer; and the like. Among these polyolefin resins, preferred are ethylene-vinyl acetate copolymer, high density polyethylene, linear low density polyethylene, and mixtures thereof. The low density is preferably 0.91 g / cm 3 ~0.94g / cm 3 and more preferably 0.91 g / cm 3~0.93g / cm 3 The high density is preferably 0.95 g / cm 3 ~0.97g / cm 3 and more preferably 0.95 g / cm 3 ~0.96g / cm 3 Medium density is a density between low and high density.

[0031] The polystyrene-based resin (I) may be a polystyrene-based resin made from recycled raw materials.

[0032] In order to enhance impact resistance or the like, the polystyrene resin (I) may contain resins other than polystyrene resins and polyolefin resins, such as (meth)acrylic resins, 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), styrene-butadiene-styrene copolymer rubber (SBS), styrene-isoprene-styrene block copolymer rubber (SIPS), styrene-butadiene-butylene-styrene copolymer rubber (SBBS), styrene-ethylene-butylene-styrene block copolymer rubber (SEBS), styrene-ethylene-propylene-styrene block copolymer rubber (SEPS), and acrylonitrile-butadiene-styrene copolymer.

[0033] As the blowing agent, any appropriate blowing agent can be used as long as it does not impair the effects of the present invention. Examples of such blowing agents include propane, i-butane, n-butane, i-pentane, n-pentane, N 2 , CO 2 , N 2 / CO 2 , water, water and -OH, -COOH, -CN, -NH 3 , -OSO 3 H, -NH, CO, NH 2 , -CONH 2 , -COOR, -CHSO 3 H, -SO 3 H, -COONH 4and mixtures thereof. In terms of being able to more effectively exhibit the effects of the present invention, the foaming agent is preferably at least one selected from i-butane and n-butane. As the foaming agent, an organic foaming agent may be used. Examples of the organic foaming agent include azodicarboxylic acid amide, dinitropentamethylenetetramine, and 4,4'-oxybis(benzenesulfonylhydrazide).

[0034] The expansion ratio of the polystyrene-based resin foam layer is preferably 1.5 to 20 times in order to more effectively exhibit the effects of the present invention.

[0035] The polystyrene-based resin foam layer may contain additives such as cell regulators, stabilizers, ultraviolet absorbers, antioxidants, colorants (including pigments), deodorants, foam nucleating agents, nucleating agents, lubricants, flame retardants, antistatic agents, etc. The additives may be of one type or two or more types.

[0036] Examples of the foam regulator include inorganic powders such as talc and silica; acid salts of polycarboxylic acids; and reaction mixtures of polycarboxylic acids with sodium carbonate or sodium bicarbonate.

[0037] Examples of the stabilizer include calcium zinc-based heat stabilizers, tin-based heat stabilizers, and lead-based heat stabilizers.

[0038] Examples of the ultraviolet ray absorbent include cesium oxide-based ultraviolet ray absorbents and titanium oxide-based ultraviolet ray absorbents.

[0039] Examples of the antioxidant include cerium oxide, cerium oxide / zirconia solid solution, cerium hydroxide, carbon, carbon nanotubes, titanium oxide, and fullerene.

[0040] Examples of colorants include titanium oxide, carbon black, titanium yellow, iron oxide, ultramarine blue, cobalt blue, calcined pigments, metallic pigments, mica, pearl pigments, zinc oxide, precipitated silica, and cadmium red.

[0041] Examples of deodorants include silica, zeolite, zirconium phosphate, and calcined hydrotalcite.

[0042] The thickness of the polystyrene-based resin foam layer may be any appropriate thickness within a range that does not impair the effects of the present invention. In the polystyrene-based resin laminated foam sheet according to the embodiment of the present invention, the thickness of the polystyrene-based resin foam layer is preferably 0.5 mm to 4.0 mm, more preferably 1.0 mm to 3.5 mm, further preferably 1.2 mm to 3.0 mm, and particularly preferably 1.5 mm to 2.5 mm. The polystyrene-based resin foam layer may be referred to as a polystyrene-based resin foam sheet.

[0043] The basis weight of the polystyrene-based resin foam layer may be any appropriate basis weight as long as the effects of the present invention are not impaired. The basis weight of the polystyrene-based resin foam layer is preferably 120 g / m2 in order to further exert the effects of the present invention. 2 ~400g / m 2 and more preferably 130 g / m 2 ~350g / m 2 and more preferably 150 g / m 2 ~300g / m 2 and particularly preferably 180 g / m 2 ~270g / m 2 It is.

[0044] The average bubble diameter of the polystyrene-based resin foam layer may be any appropriate average bubble diameter within a range that does not impair the effects of the present invention. The average bubble diameter of the polystyrene-based resin foam layer is preferably 80 μm to 300 μm, more preferably 90 μm to 250 μm, even more preferably 100 μm to 220 μm, and particularly preferably 110 μm to 200 μm, in order to further exhibit the effects of the present invention.

[0045] The polystyrene-based resin foam layer has an apparent density, measured by the method described in JIS K7222:1999 "Foamed plastics and rubber - Measurement of apparent density", of preferably 0.045 g / cm3, from the viewpoint of further exerting the effects of the present invention. 3 ~0.300g / cm 3 and more preferably 0.070 g / cm 3 ~0.250g / cm 3 It is.

[0046] The polystyrene foam layer has a volume (V 2 ) and the apparent volume of the foam layer (V 1 The open cell ratio, as measured from the above formula based on the following formula, is preferably 20% or less, and more preferably 10% or less. Open cell ratio (%) = 100 × [(V 1 -V 2 ) / V 1 ]

[0047] The polystyrene-based resin foam layer is low oligomer grade, and the total content of styrene dimer and styrene trimer in the polystyrene-based resin foam layer is preferably 2000 ppm or less, more preferably 1800 ppm or less, further preferably 1500 ppm or less, and particularly preferably 1200 ppm or less. The polystyrene-based resin laminated foam sheet according to the embodiment of the present invention can exhibit the effect of being less susceptible to appearance defects during thermoforming, even if a low oligomer grade polystyrene-based resin foam layer is used.

[0048] <Polystyrene resin layer> The polystyrene-based resin layer is typically a non-expanded polystyrene-based resin layer.

[0049] The thickness of the polystyrene resin layer may be any appropriate thickness within a range that does not impair the effects of the present invention. In the polystyrene resin laminated foam sheet according to the embodiment of the present invention, the thickness of the polystyrene resin layer is preferably 5.0 μm to 250 μm, more preferably 10 μm to 200 μm. The polystyrene resin layer may be typically referred to as a polystyrene resin film. The thickness of the polystyrene resin layer is preferably smaller than the thickness of the polystyrene resin foam layer, more preferably 1 / 5 or less of the thickness of the polystyrene resin foam layer, and even more preferably 1 / 10 or less of the thickness of the polystyrene resin foam layer.

[0050] The melt tension of the polystyrene resin layer at 200°C is preferably 10cN to 40cN, more preferably 12cN to 35cN, further preferably 15cN to 30cN, and particularly preferably 18cN to 28cN. If the melt tension of the polystyrene resin layer at 200°C is adjusted within the above range, the effects of the present invention can be more effectively achieved. If the melt tension of the polystyrene resin layer at 200°C is too low outside the above range, it becomes difficult to apply appropriate stretching to the polystyrene resin layer side of the polystyrene resin laminated foamed sheet when producing a polystyrene resin laminated foam container by thermoforming, and as a result, there is a risk of occurrence of poor appearance such as unevenness on the polystyrene resin layer side when performing thermoforming under conditions such as high cycle, and for example, there is a risk of occurrence of abnormalities such as ink loss in a printing process for improving design. If the melt tension of the polystyrene-based resin layer at 200°C is too high and falls outside the above range, there is a risk that sufficient elongation will not be obtained when producing a polystyrene-based resin laminated foam container by thermoforming due to the polystyrene-based resin layer having too high a tension, and there is a risk of internal cracks, known as "cracks," occurring in the polystyrene-based resin laminated foam container.

[0051] The polystyrene resin layer contains a polystyrene resin (II) and a rubber-modified polystyrene resin. The weight ratio of the polystyrene resin (II) and the rubber-modified polystyrene resin contained in the polystyrene resin layer is preferably 10:90 to 60:40, more preferably 15:85 to 55:45, further preferably 20:80 to 50:50, and particularly preferably 25:75 to 45:55. If the weight ratio of the polystyrene resin (II) and the rubber-modified polystyrene resin contained in the polystyrene resin layer is adjusted within the above range, the effect of the present invention can be more effectively exhibited. This is because it is considered that if the weight ratio of the polystyrene resin (II) and the rubber-modified polystyrene resin contained in the polystyrene resin layer is adjusted within the above range, the polystyrene resin laminated foam container manufactured by thermoforming can exhibit both the rigidity characteristic of the polystyrene resin and the impact resistance characteristic of the rubber-modified polystyrene.

[0052] The total content of the polystyrene resin (II) and the rubber-modified polystyrene resin in the polystyrene resin layer is preferably 50% by weight to 100% by weight, more preferably 70% by weight to 100% by weight, further preferably 90% by weight to 100% by weight, and particularly preferably 98% by weight to 100% by weight. If the total content of the polystyrene resin (II) and the rubber-modified polystyrene resin in the polystyrene resin layer is adjusted to within the above range, the effects of the present invention can be more effectively exhibited.

[0053] Specifically, the polystyrene resin layer is preferably formed by heating and melting and kneading a resin composition containing a polystyrene resin (II) and a rubber-modified polystyrene resin together with various additives added as necessary in an extruder, cooling to a predetermined temperature, and extruding from a die into a film shape. More specifically, in producing a polystyrene resin laminated foam sheet according to an embodiment of the present invention, preferably, as described below, a resin composition containing a polystyrene resin (II) and a rubber-modified polystyrene resin together with various additives added as necessary in an extruder, cooling to a predetermined temperature, and extruding from a die into a film shape. The film is laminated on the surface of the polystyrene resin foam layer.

[0054] The polystyrene resin (II) contained in the polystyrene resin layer may be the same as that described for the polystyrene resin (I) forming the polystyrene resin foam layer, as long as the effect of the present invention is not impaired. The polystyrene resin (II) contained in the polystyrene resin layer may be the same as or different from the polystyrene resin (I) forming the polystyrene resin foam layer.

[0055] The polystyrene resin (II) may be of one type only, or of two or more types.

[0056] The polystyrene resin (II) preferably has an MFR of 0.4 g / 10 min to 5.0 g / 10 min, more preferably 0.6 g / 10 min to 4.0 g / 10 min, still more preferably 0.8 g / 10 min to 3.5 g / 10 min, and particularly preferably 1.0 g / 10 min to 3.0 g / 10 min, in terms of being able to more effectively exhibit the effects of the present invention.

[0057] The polystyrene resin (II) has a weight average molecular weight (Mw) of preferably 240,000 to 460,000, more preferably 260,000 to 440,000, still more preferably 280,000 to 420,000, and particularly preferably 300,000 to 400,000, in order to more effectively exert the effects of the present invention.

[0058] The polystyrene resin (II) has a Z-average molecular weight (Mz) of preferably 500,000 to 1,200,000, more preferably 600,000 to 1,100,000, still more preferably 700,000 to 1,000,000, and particularly preferably 800,000 to 950,000, in terms of being able to more effectively exhibit the effects of the present invention.

[0059] In terms of being able to more effectively exert the effects of the present invention, the polystyrene resin (II) preferably has a ratio (Mz / Mw) of Z-average molecular weight (Mz) to weight-average molecular weight (Mw) of 1.9 to 3.5, more preferably 2.0 to 3.2, and even more preferably 2.1 to 3.0.

[0060] The rubber-modified polystyrene resin contained in the polystyrene resin layer may be one in which the molecules themselves are modified, or one which is modified in a bulk state. Examples of such rubber-modified polystyrene resins include copolymers of one or more styrene monomers and one or more rubber component monomers, and blends of one or more polystyrene resins and one or more rubbers.

[0061] Specific examples of rubber-modified polystyrene resins include so-called high impact polystyrene resin (HIPS) and mixed resins of high impact polystyrene resin (HIPS: high impact polystyrene) and styrene homopolymers such as general purpose polystyrene resin (GPPS).

[0062] When a mixed resin of high impact polystyrene resin (HIPS) and general purpose polystyrene resin (GPPS) is used as the rubber-modified polystyrene resin, it is preferable that the mixed resin contains 40% by weight or more of high impact polystyrene resin (HIPS) from the viewpoint of imparting impact resistance, etc.

[0063] Any suitable high impact polystyrene resin (HIPS) may be used as the high impact polystyrene resin (HIPS) as long as the effects of the present invention are not impaired. Examples of such high impact polystyrene resin (HIPS) include those in which a styrene-butadiene copolymer is dispersed in a salami structure and the particle size is 0.3 μm to 10 μm. Further, examples of the polystyrene resin (II) forming the polystyrene resin layer include linear low-density polyethylene, high-density polyethylene, low-density polyethylene, propylene homopolymer, ethylene-propylene random polymer, ethylene-propylene block polymer, ethylene-propylene-butene-terpolymer, ethylene-vinyl acetate copolymer, ethylene-unsaturated carboxylic acid ester copolymer (e.g., ethylene-methyl methacrylate copolymer), ethylene-unsaturated carboxylic acid metal salt copolymer (e.g., ethylene-magnesium (or zinc) acrylate copolymer), propylene-vinyl chloride copolymer, propylene-butene copolymer, propylene-maleic anhydride copolymer, propylene-olefin copolymer (propylene-ethylene copolymer, propylene-butene-1 copolymer), unsaturated carboxylic acid (e.g., maleic anhydride) modified polyethylene or polypropylene, ethylene-propylene rubber, atactic polypropylene, polyethylene terephthalate, polybutylene terephthalate, and mixtures thereof.

[0064] The polystyrene resin layer may contain additives such as stabilizers, ultraviolet absorbers, antioxidants, colorants (including pigments), deodorants, lubricants, flame retardants, and antistatic agents. The additives may be one type or two or more types. The explanation of these additives may be cited from the explanation of the additives that may be added to the polystyrene resin foam layer.

[0065] <Production method of polystyrene-based resin laminated foam sheet> The method for producing the polystyrene-based resin laminated foam sheet according to the embodiment of the present invention may be any appropriate method as long as the effects of the present invention are not impaired. The method for producing the polystyrene-based resin laminated foam sheet according to the embodiment of the present invention is, in terms of being able to more effectively exhibit the effects of the present invention, typically: (1) a polystyrene-based resin foam layer manufacturing process; (2) A polystyrene-based resin layer manufacturing and lamination process; The method for producing a polystyrene-based resin laminated foam sheet according to an embodiment of the present invention preferably includes, in this order, (1) a polystyrene-based resin foam layer producing step, and (2) a polystyrene-based resin layer producing / laminating step.

[0066] In the process for producing a polystyrene-based resin foam layer, typically, the polystyrene-based resin (I) is heated, melted, and kneaded in an extruder together with various additives such as a foaming agent and, if necessary, a cell regulator, and then cooled to a predetermined temperature, extruded from a die into a sheet shape and foamed, and then immediately cooled. This produces a sheet-like polystyrene-based resin foam layer. When a foaming gas is used as the foaming agent, the produced polystyrene-based resin foam layer is left for a while, and the foaming gas remaining in the polystyrene-based resin foam layer is replaced with air.

[0067] In the process for producing a polystyrene-based resin foam layer, specifically, for example, a molten mixture containing a polystyrene-based resin (I), a foaming agent, and various additives such as a bubble regulator added as necessary is extruded from the outlet of a circular die to form a cylindrical foam, and the foam is drawn while the inner surface of the foam is brought into sliding contact with the outer peripheral surface of a cooling mandrel arranged downstream (forward in the extrusion direction) of the circular die and having a diameter larger than the outlet of the circular die, and the foam is expanded in diameter by the cooling mandrel and cooled from the inside. The foam is continuously cut in the extrusion direction by a cutter arranged downstream of the cooling mandrel to develop it into a flat sheet.

[0068] In the polystyrene-based resin layer production / lamination process, typically, a resin composition containing a polystyrene-based resin (II) and a rubber-modified polystyrene-based resin is heated, melted, and kneaded in an extruder together with various additives added as necessary, cooled to a predetermined temperature, extruded from a die into a film, and laminated on the surface of a polystyrene-based resin foam layer before being completely cooled, and during the lamination, a heat treatment is performed on the polystyrene-based resin foam layer side. This results in a laminate of a polystyrene-based resin foam layer and a polystyrene-based resin layer.

[0069] In the polystyrene-based resin layer manufacturing / laminating process, specifically, for example, the polystyrene-based resin foam layer can be extruded by an extrusion lamination method using a flat die. Such an extrusion lamination method can be implemented, for example, by using a conveying mechanism for horizontally conveying the polystyrene-based resin foam layer, an extrusion mechanism for extruding the molten polystyrene resin (II) and the above-mentioned resin composition on the upper surface side of the horizontally conveyed polystyrene-based resin foam layer, and a thickness correction mechanism for regulating the total thickness of the polystyrene-based resin foam layer and the above-mentioned molten resin composition coated on the polystyrene-based resin foam layer. The conveying mechanism can be configured, for example, by a feeder that can rotate the original roll wound into a roll in the opposite direction to the winding direction to feed out the polystyrene-based resin foam layer from the outside, and a winder that can wind up the polystyrene-based resin foam layer fed from the feeder into a roll again. The extrusion mechanism can be configured by a flat die having an opening width equivalent to the width of the polystyrene-based resin foam layer, and an extruder with the flat die attached to its tip. The thickness correction mechanism can be configured by a thickness correction device having two thickness correction rolls each having a length longer than the width of the polystyrene-based resin foam layer, the two thickness correction rolls being arranged so that their rotation axes are horizontal and parallel to one another, and the outer peripheral surface distance can be freely adjusted by moving them closer to or farther away from each other.

[0070] More specifically, in the polystyrene-based resin layer production / lamination process, the process can be carried out by setting an original roll in a delivery machine, passing the polystyrene-based resin foam layer unwound from the delivery machine between thickness correction rolls and setting its leading end in the winder, setting the outer peripheral surface spacing of the thickness correction rolls to a spacing corresponding to the thickness of the polystyrene-based resin laminated foam sheet to be formed, and setting the extruder so that the heated and molten resin composition is extruded from a flat die onto the upper surface of the polystyrene-based resin foam layer just before the thickness correction rolls. That is, a delivery machine and a winder are operated in cooperation to move the polystyrene-based resin foam layer in the lengthwise direction, while the heated and molten resin composition is extruded from the flat die so as to spread across the entire width of the polystyrene-based resin foam layer, and the polystyrene-based resin foam layer with the heated and molten resin composition laminated on the upper surface side is passed between thickness correction rolls, and the laminated resin composition is sufficiently cooled by the upper thickness correction roll and the surface is smoothed, thereby producing a polystyrene-based resin laminated foam sheet in which a polystyrene-based resin layer having a uniform in-plane thickness is laminated on the upper side of the polystyrene-based resin foam layer.

[0071] It is preferable to provide an appropriate curing period for the polystyrene-based resin foam layer between the polystyrene-based resin foam layer manufacturing step and the polystyrene-based resin layer manufacturing / laminating step, and after the polystyrene-based resin foam layer manufacturing step, it is preferable to cure the polystyrene-based resin foam layer at a temperature of 20°C to 40°C for about 10 to 30 days before carrying out the polystyrene-based resin layer manufacturing / laminating step.

[0072] The heat treatment step can be carried out using a general heating device such as a hot air fan, a radiant heater, or a heated roll, and can usually be carried out by blowing hot air at 50°C to 120°C from a position 10cm to 25cm away from the surface of the polystyrene-based resin laminate foam sheet to heat the polystyrene-based resin laminate foam sheet from the polystyrene-based resin layer side. The heat treatment step may be carried out on the polystyrene-based resin laminate foam sheet after passing through the correction roll in the polystyrene-based resin layer production / lamination step and before being wound up by the winder. That is, the heat treatment step may be carried out continuously to the polystyrene-based resin layer production / lamination step. In addition, the heat treatment step may be carried out after the polystyrene-based resin laminate foam sheet is once wound up into a roll, and then, for example, after a period of about 12 hours to 10 days, the heat treatment step may be carried out.

[0073] In the winding step, the laminate of the polystyrene-based resin foam layer and the polystyrene-based resin layer is wound up by a winding device such as a roll.

[0074] <Polystyrene-based resin laminated foam container> The polystyrene-based resin laminated foam container according to an embodiment of the present invention is formed by thermoforming a polystyrene-based resin laminated foam sheet, and one embodiment of the polystyrene-based resin laminated foam container according to an embodiment of the present invention is formed by molding a polystyrene-based resin laminated foam sheet according to an embodiment of the present invention into a container shape so that the polystyrene-based resin layer is on the outside of the container.

[0075] To manufacture a polystyrene-based resin laminated foam container according to an embodiment of the present invention using the polystyrene-based resin laminated foam sheet according to an embodiment of the present invention, the polystyrene-based resin laminated foam sheet wound into a roll is heated to a constant temperature in the heating zone of a molding machine, and then molded into a desired container shape in the molding zone. The container shape can be, for example, a bowl shape, a cup shape, a box shape, a tray shape, or any other shape.

[0076] The polystyrene-based resin laminated foam container according to an embodiment of the present invention is typically formed into a container shape such that, as shown in FIG. 4, the polystyrene-based resin laminated foam sheet according to the embodiment of the present invention has a polystyrene-based resin foam layer on the inside and a polystyrene-based resin layer on the inside. In FIG. 4, the inside of the container of the polystyrene-based resin laminated foam container 1000 is 200, and the outside of the container is 300.

Example

[0077] Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited to these examples. The measurement methods and evaluation methods for each property are as follows.

[0078] <Melt Tension> The melt tension was measured using a twin-bore capillary rheometer "Rheologic5000T" manufactured by Thiasoft as the measuring device. The melt tension was measured with a capillary die having a diameter of 2.095 mm, a length of 8 mm, and an inlet angle of 90 degrees (conical) set in the above measuring device and a pulley for detecting tension located 27 cm below this capillary die. First, the measuring sample was filled into a barrel with a diameter of 15 mm heated to a test temperature of 200°C. The filled measuring sample was preheated for 5 minutes to be melted. The melt was extruded from the capillary die in a string shape while keeping the piston lowering speed (0.07730 mm / s) constant. After passing this string through the pulley for detecting tension, it was wound up using a winding roll. The initial winding speed was set to 4 mm / s. The winding speed was gradually increased with an acceleration of 12 mm / s 2 until the string was cut. The average of the maximum and minimum values of the tension immediately before the point where the string was cut was defined as the melt tension (MT) of the measuring sample.

[0079] <Measurement of MFR> The measurement of the melt mass flow rate (MFR) of the polystyrene-based resin was carried out according to the method described in Method B of JIS K 7210:1999 "Plastics - Test Method for Melt Mass Flow Rate (MFR) and Melt Volume Flow Rate (MVR) of Thermoplastic Plastics". Equipment: Semi-automatic melt indexer (manufactured by Toyo Seiki Co., Ltd.) Test temperature: 200℃ Test load: 5.0kgf Operation method: B method Heating time: 5 minutes

[0080] <Weight average molecular weight> The weight average molecular weight (Mw) means the weight average molecular weight in terms of polystyrene (PS) measured using gel permeation chromatography (GPC). Specifically, the weight average molecular weight was measured as follows. 6 mg of a sample was dissolved in 6 mL of THF (tetrahydrofuran) (immersion time: 6 ± 1 hr (complete dissolution)) to obtain a sample solution. The sample solution was filtered through a non-aqueous 0.45 μm syringe filter manufactured by Shimadzu GLC Co., Ltd. to obtain a filtrate. The obtained filtrate was measured using gel permeation chromatography (GPC) under the following measurement conditions, and the weight average molecular weight (Mw) was calculated from a standard polystyrene calibration curve prepared in advance. (Equipment used) Tosoh Corporation's "HLC-8320GPC EcoSEC", gel permeation chromatograph (with built-in RI and UV detectors) (column) Sample side Guard column = TSK guardcolumn SuperMP(HZ)-H (4.6mmI.D.×2cm) x 1, manufactured by Tosoh Corporation Measurement column: Tosoh Corporation's TSKgel SuperMultiporeHZ-H (4.6 mm I.D. x 15 cm) x 2 in series Reference Side Tosoh Corporation TSKgel Super HZ1000 (6.0mm I.D. x 15cm) x 1 (Various conditions) Column temperature = 40 °C Mobile phase=THF Mobile phase flow rate Sample pump: 0.2mL / min Reference pump = 0.2mL / min Detector = RI detector Sample concentration = 0.1 wt% Injection volume = 20μL Measurement time = 26 min Sampling pitch = 200 msec (method) The standard polystyrene samples used for the calibration curve were "STANDARD SM-105" and "STANDARD SH-75" manufactured by Showa Denko K.K., with weight average molecular weights of 5,620,000, 3,120,000, 1,250,000, 442,000, 151,000, 53,500, 17,000, 7,660, 2,900, and 1,320. The above-mentioned standard polystyrene samples for the calibration curve were grouped into A (5,620,000, 1,250,000, 151,000, 17,000, 2,900) and B (3,120,000, 442,000, 53,500, 7,660, 1,320), and then A (2mg, 3mg, 4mg, 4mg, 4mg) was weighed and dissolved in 30mL of THF, and B (3mg, 4mg, 4mg, 4mg) was weighed and dissolved in 30mL of THF. The standard polystyrene calibration curve was obtained by injecting 20μL of the prepared solutions of A and B and creating a calibration curve (linear equation) from the retention times obtained after measurement. The weight average molecular weight was calculated using the calibration curve.

[0081] <Measurement of the total content of styrene dimer and styrene trimer in the polystyrene resin foam layer> About 0.2 g of a sample was taken from the polystyrene-based resin laminated foam sheet while maintaining the weight ratio of the polystyrene-based resin foam layer and the polystyrene-based resin layer in the polystyrene-based resin laminated foam sheet, dissolved in 10 ml of methyl ethyl ketone, dropped into 35 ml of methanol to cause reprecipitation, and stirred for about 1 hour. Next, the above reprecipitated solution was filtered into a 50 ml measuring flask using No. 5A filter paper and dissolved in methanol to a constant volume of 50 ml. Next, 10 μl of the internal standard pyrene (1000 ppm methanol solution) was placed in a 2 ml measuring flask and dissolved in the methanol solution in the 50 ml measuring flask to a constant volume of 2 ml to prepare a sample solution. Next, using this sample solution, GC / MS measurement was performed under the following conditions. The peak areas of three styrene dimer peaks and five styrene trimer peaks in the obtained chromatogram were quantified using a calibration curve of styrene oligomers prepared in advance as a relative sensitivity to the peak area of ​​pyrene, which is an internal standard substance. The calibration curves of styrene dimer and styrene trimer were prepared using standard substances manufactured by Kanto Chemical Co., Ltd. The total content (unit: ppm) in the polystyrene resin was calculated from the total amount of styrene dimer and styrene trimer obtained in this way. (GC / MS measurement conditions) Equipment: Shimadzu Corporation, gas chromatograph mass spectrometer "QP5050A (GC=GC-17A)" Column: ZB-5MS (Phenomenex, 0.25 μm × 0.25 mmφ × 30 m) GC oven heating conditions: Initial temperature 100℃ (1 min) First stage heating rate: 10℃ / min (hold for 2.5 minutes until 190℃) Second stage heating rate: 10℃ / min (up to 300℃) Final temperature 300℃ (2.5 minutes) Inlet temperature: 240℃ Detector temperature: 260℃ Detector: 1.25kV Carrier gas: Helium Total flow: 15.3mL / min Column flow rate: 1.0 mL / min Carrier gas pressure: 75kPa Test liquid injection volume: 2 μl (using autosampler) Split ratio: 1 / 12

[0082] <Polystyrene-based resin laminated foam container> Container A having a cross-sectional shape as shown in Fig. 3 was produced by thermoforming a polystyrene-based resin laminated foam sheet. Container A was produced so that the polystyrene-based resin foam layer was on the inside (the polystyrene-based resin layer was on the outside). Container A had an inner diameter of 140 mm at the opening, an inner diameter of 100 mm at the bottom, a depth of 80 mm, and a drawing ratio of 0.57. Container A was produced using a press molding device having a cavity (concave mold) with 6 x 6 = 36 concave portions corresponding to the outer shape of container A, and a plug (convex mold) with the same number of convex portions as the concave portions corresponding to the inner shape of container A. Container A was produced by continuously supplying a long strip of polystyrene resin laminated foam sheet to this press molding device in the length direction. The molding conditions were as follows: molding cycle for one shot (=36 pieces) was 5.0 seconds, heater temperature on the cavity side was set to 350°C, heater temperature on the plug side was set to 260°C, mold temperature on the cavity side was set to 60°C, and mold temperature on the plug side was set to 120°C. The timing of molding was set so that the cavity and the plug came into contact with the laminated polystyrene resin foam sheet at almost the same time to start molding.

[0083] <Evaluation of container appearance> The appearance of 36 containers from the first shot, immediately after the start of operation of the press molding machine, and 36 containers from the 30th shot, when the mold was thought to have been sufficiently warmed up through repeated molding, were observed. Then, the containers in each Example and Comparative Example were observed for any abnormalities in appearance, such as wrinkles or cracks (internal cracks). Those in which no abnormality was observed were rated as "○", and those in which abnormality was observed were rated as "×".

[0084] <Evaluation of curved surface printing> The outer peripheral surface of the container was printed using a curved surface printing machine. The printed surface was visually observed, and a case where no "faded" print was observed was rated "◯", and a case where "faded" print was observed was rated "X".

[0085] <Resin materials> The following resin materials were used to manufacture the polystyrene-based resin laminated foam sheet. (1) Toyo Styrene Co., Ltd., impact-resistant polystyrene resin (rubber-modified polystyrene resin), product name "E641N", MFR: 3.6g / 10min (2) Toyo Styrene Co., Ltd., impact-resistant polystyrene resin (rubber-modified polystyrene resin), product name "E640N", MFR: 2.7g / 10min (3) PS Japan, impact-resistant polystyrene resin (rubber-modified polystyrene resin), product name "475D", MFR: 2.2g / 10min (4) Polystyrene resin (GPPS), GP1, MFR: 2.0 g / 10 min, Mw=325000, Mz=892000, Mz / Mw=2.74, melt tension=21.9 cN (0.219 N) (5) Polystyrene resin (GPPS), GP2, MFR: 2.1 g / 10 min, Mw = 311000, Mz = 902000, Mz / Mw = 2.90, melt tension = 19.5 cN (0.195 N) (6) Polystyrene resin (GPPS), GP3, MFR: 1.3 g / 10 min, Mw = 359000, Mz = 822000, Mz / Mw = 2.29, melt tension = 18.5 cN (0.185 N) (7) Polystyrene resin (GPPS), GP4, MFR: 1.4 g / 10 min, Mw = 340,000, Mz = 855,000, Mz / Mw = 2.51, melt tension = 27.9 cN (0.279 N) (8) Polystyrene resin, manufactured by PS Japan, product name "G0002", MFR: 2.0 g / 10 min, Mw=271000, Mz=480000, Mz / Mw=1.77, melt tension=8.7 cN (0.087 N) (9) Toyo Styrene Co., Ltd., polystyrene resin (polystyrene-based resin), product name "HRM52N", MFR: 2.6 g / 10 min, Mw=261000, Mz=491000, Mz / Mw=1.88, melt tension=7.4 cN (0.074 N)

[0086] [Production Example 1] A mixed butane containing 62% by weight of isobutane and % by weight of normal butane was melt-kneaded together with a polystyrene resin (manufactured by PS Japan, product name "G0002", MFR: 2.0 g / 10 min) in an extruder to prepare a melt-kneaded product containing 3.34% by weight of the mixed butane. The melt-kneaded product was extruded and foamed to a thickness of 2.05 mm and a basis weight of 240 g / m.2 , density 0.117g / cm 3 The polystyrene-based resin foamed sheet (1) was produced. The total content of styrene dimer and styrene trimer in the polystyrene-based resin foamed layer (1) was 845 ppm.

[0087] [Example 1] (Production of polystyrene-based resin laminated foam sheets) The polystyrene-based resin foam sheet (1) (which will become the polystyrene-based resin foam layer) obtained in Production Example 1 was cured at room temperature (20°C to 40°C) for 28 days, and then a resin composition (1) blended as shown in Table 1 was heated and melted under conditions that the resin temperature reached 250°C and laminated on one side of the polystyrene-based resin foam sheet (1) to a thickness of 114 μm and a basis weight of 120 g / m. 2 The polystyrene resin layer was laminated to obtain a polystyrene resin laminated foam sheet (1). A heat treatment step was carried out on the obtained polystyrene-based resin laminated foam sheet (1) by blowing hot air at 90°C from a position 15 cm away from the surface on the polystyrene-based resin layer side to heat the polystyrene-based resin laminated foam sheet (1) from the polystyrene-based resin layer side. The results are shown in Table 1.

[0088] [Example 2] The same procedure as in Example 1 was carried out except that the blended resin composition (2) shown in Table 1 was used instead of the blended resin composition (1), to obtain a laminated polystyrene resin foam sheet (2). The results are shown in Table 1.

[0089] [Example 3] The same procedure as in Example 1 was carried out except that the blended resin composition (3) shown in Table 1 was used instead of the blended resin composition (1), to obtain a laminated polystyrene resin foam sheet (3). The results are shown in Table 1.

[0090] [Example 4] The same procedure as in Example 1 was carried out except that the blended resin composition (4) shown in Table 1 was used instead of the blended resin composition (1), to obtain a laminated polystyrene resin foam sheet (4). The results are shown in Table 1.

[0091] [Example 5] The same procedure as in Example 1 was carried out except that the blended resin composition (5) shown in Table 1 was used instead of the blended resin composition (1), to obtain a laminated polystyrene resin foam sheet (5). The results are shown in Table 1.

[0092] [Comparative Example 1] The same procedure as in Example 1 was carried out except that the blended resin composition (C1) shown in Table 1 was used instead of the blended resin composition (1), to obtain a laminated polystyrene resin foam sheet (C1). The results are shown in Table 1.

[0093] [Comparative Example 2] The same procedure as in Example 1 was carried out except that the blended resin composition (C2) shown in Table 1 was used instead of the blended resin composition (1), to obtain a laminated polystyrene resin foam sheet (C2). The results are shown in Table 1.

[0094] [Comparative Example 3] The same procedure as in Example 1 was carried out except that the blended resin composition (C3) shown in Table 1 was used instead of the blended resin composition (1), to obtain a laminated polystyrene resin foam sheet (C3). The results are shown in Table 1.

[0095] [Comparative Example 4] The same procedure as in Example 1 was carried out except that the blended resin composition (C4) shown in Table 1 was used instead of the blended resin composition (1), to obtain a laminated polystyrene resin foam sheet (C4). The results are shown in Table 1.

[0096] [Table 1] [Industrial Applicability]

[0097] The laminated thermoplastic resin foam sheet according to the embodiment of the present invention can be suitably used as a material for containers for instant cup noodles, etc. The laminated polystyrene resin foam container according to the embodiment of the present invention can be suitably used as a container for instant cup noodles, etc. [Explanation of symbols]

[0098] 100 Polystyrene resin laminated foam sheet 10 Polystyrene resin foam layer 10a Surface on the side of the polystyrene resin foam layer 20 Polystyrene resin layer 20a Surface on the polystyrene resin layer side 1000 Foam Containers 200 Inside the container 300 Outside the container

Claims

1. A polystyrene-based resin laminated foam sheet having a non-expanded polystyrene-based resin layer laminated on at least one surface of a polystyrene-based resin foam layer, The polystyrene-based resin foam layer is formed by foaming a polystyrene-based resin (I), the total content of styrene dimer and styrene trimer in the polystyrene-based resin foam layer is 2000 ppm or less; the non-expanded polystyrene-based resin layer contains a polystyrene-based resin (II) and a rubber-modified polystyrene-based resin in a weight ratio of polystyrene-based resin (II):rubber-modified polystyrene-based resin=10:90 to 60:40; The weight average molecular weight (Mw) of the polystyrene resin (II) is 280,000 to 460,000; The Z-average molecular weight (Mz) of the polystyrene resin (II) is 500,000 to 1,200,000; Polystyrene resin laminated foam sheet.

2. 2. The polystyrene-based resin laminate foam sheet according to claim 1, having a thickness of 0.5 mm to 4.0 mm.

3. Basis weight 200g / m 2 Up to 800 g / m 2 The laminated polystyrene resin foam sheet according to claim 1 or 2,

4. A polystyrene-based resin laminate foam container, which is thermoformed from the polystyrene-based resin laminate foam sheet according to any one of claims 1 to 3.

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