JP2021062600A - Thermoplastic resin laminate foam sheet and thermoplastic resin laminate foam container - Google Patents

Abstract

To provide a thermoplastic resin laminate foam sheet which can reduce an environmental load and is excellent in impact resistance and molding ability, and a thermoplastic resin laminate foam container.SOLUTION: A thermoplastic resin laminate foam sheet 1 has a foam layer 10 and a non-foam layer 20 positioned on one surface or both surfaces of the foam layer 10, in which the non-foam layer 20 contains a low environmental load resin, a temperature width of a crystallization heat peak of the non-foam layer 20 in a second DSC curve that is measured using a heat flux differential scan calorimetric measuring device is 60°C or lower, and a dimensional change ratio when being heated at 125°C for 2.5 minutes is 40% or less.SELECTED DRAWING: Figure 1

Description

The present invention relates to a thermoplastic resin laminated foam sheet and a thermoplastic resin laminated foam container.

It is generally known that a container formed of a thermoplastic resin laminated foam sheet is lightweight and has excellent heat insulating properties. Therefore, such a container is widely used as a container for foods such as instant noodles that are cooked by pouring boiling water.

In recent years, it has been desired to use a resin that can reduce the environmental load in consideration of the global environment. As a resin capable of reducing the environmental load (sometimes referred to as a "low environmental load resin"), for example, a biodegradable resin, a plant-derived resin, or the like is known. However, if the low environmental load resin is simply used for the foam layer, the desired foam layer cannot be formed, and the impact resistance tends to decrease.
For example, Patent Document 1 proposes a laminated foam sheet in which a polylactic acid-based resin film, which is a biodegradable resin, is applied to a surface coating layer.

Japanese Unexamined Patent Publication No. 2012-131173

However, when the low environmental load resin is simply used for the non-foamed layer, there is a problem that the surface of the laminated foamed sheet does not stretch and the moldability is inferior.

Therefore, an object of the present invention is a thermoplastic resin laminated foam sheet and a thermoplastic resin laminated foam container which can reduce the environmental load and are excellent in impact resistance and moldability.

In order to solve the above problems, the present invention has the following aspects.
[1] The foamed layer has a foamed layer and a non-foamed layer located on one side or both sides of the foamed layer. The non-foamed layer contains a low environmental load resin and is measured by using a heat flux differential scanning calorimetry device. The temperature width of the crystallization heat peak of the non-foamed layer in the second DSC curve is 60 ° C. or less, and the dimensional change rate when heated at 125 ° C. for 2.5 minutes is 40% or less. Plastic resin laminated foam sheet.
[2] The thermoplastic resin laminated foam sheet according to [1], wherein the low environmental load resin is both or one of a biodegradable resin and a plant-derived resin.
[3] The thermoplastic resin laminated foam sheet according to [1] or [2], wherein the non-foamed layer contains a polystyrene resin.
[4] The thermoplastic resin laminated foam sheet according to [3], wherein the polystyrene-based resin contains a high-impact polystyrene resin.
[5] The item according to any one of [1] to [4], wherein the content of the low environmental load resin is 90% by mass or less with respect to the total mass of the resin contained in the non-foamed layer. Thermoplastic resin laminated foam sheet.
[6] The thermoplastic resin laminated foam according to any one of [1] to [5], wherein the temperature range of the crystallization heat peak of the non-foamed layer in the second DSC curve is 50 ° C. or less. Sheet.
[7] The thermoplastic resin laminated foam sheet according to any one of [1] to [6], wherein the peak top temperature of the heat crystallization peak is 125 ° C. or lower.
[8] The thermoplastic resin laminated foam according to any one of [1] to [7], wherein the low environmental load resin contains a biodegradable resin and the biodegradable resin is a polylactic acid-based resin. Sheet.
[9] The thermoplastic resin laminated foam sheet according to [8], wherein the polylactic acid-based resin has a Z average molecular weight of 800,000 or less.
[10] The thermoplastic resin laminate according to [8] or [9], wherein the content of the biodegradable resin is 3 to 90% by mass with respect to the total mass of the resin contained in the non-foamed layer. Foam sheet.
[11] The non-foaming layer contains a surfactant, and the content of the surfactant is 0.01 to 2.0 parts by mass with respect to 100 parts by mass of the total mass of the resin contained in the non-foaming layer. The thermoplastic resin laminated foam sheet according to any one of [1] to [10].
[12] The thermoplastic resin laminated foam sheet according to [11], wherein the surfactant is a nonionic surfactant.
[13] A thermoplastic resin laminated foam container obtained by molding a thermoplastic resin laminated foam sheet having a foam layer and a non-foam layer located on one side or both sides of the foam layer, and is a thermoplastic resin laminated foam container having both an inner surface and an outer surface or The non-foamed layer has the non-foamed layer on either one, the non-foamed layer contains a low environmental load resin, and the non-foamed layer in the second DSC curve measured using a heat flow differential scanning calorimetry device. A thermoplastic resin laminated foam container having a temperature range of 60 ° C. or less and a dimensional change rate of 40% or less when heated at 125 ° C. for 2.5 minutes.
[14] The thermoplastic resin laminated foam container according to [13], wherein the low environmental load resin is both or one of a biodegradable resin and a plant-derived resin.
[15] The thermoplastic resin laminated foam container according to [13] or [14], wherein the non-foamed layer contains a polystyrene resin.
[16] The thermoplastic resin laminated foam container according to [15], wherein the polystyrene-based resin contains a high-impact polystyrene resin.
[17] The item according to any one of [13] to [16], wherein the content of the low environmental load resin is 90% by mass or less with respect to the total mass of the resin contained in the non-foamed layer. Thermoplastic resin laminated foam container.
[18] The thermoplastic resin laminated foam according to any one of [13] to [17], wherein the temperature range of the crystallization heat peak of the non-foamed layer in the second DSC curve is 50 ° C. or less. container.
[19] The thermoplastic resin laminated foam container according to any one of [13] to [18], wherein the peak top temperature of the crystallization heat peak is 125 ° C. or lower.
[20] The thermoplastic resin laminated foam according to any one of [13] to [19], wherein the low environmental load resin contains a biodegradable resin and the biodegradable resin is a polylactic acid-based resin. container.
[21] The thermoplastic resin laminated foam container according to [20], wherein the polylactic acid-based resin has a Z average molecular weight of 800,000 or less.
[22] The thermoplastic resin laminate according to [20] or [21], wherein the content of the biodegradable resin is 3 to 90% by mass with respect to the total mass of the resin contained in the non-foamed layer. Foam container.
[23] The non-foaming layer contains a surfactant, and the content of the surfactant is 0.01 to 2.0 parts by mass with respect to 100 parts by mass of the total mass of the resin contained in the non-foaming layer. The thermoplastic resin laminated foam container according to any one of [13] to [22].
[24] The thermoplastic resin laminated foam container according to [23], wherein the surfactant is a nonionic surfactant.
[25] The thermoplastic resin laminated foam container according to any one of [13] to [24], which is a container for food.

According to the thermoplastic resin laminated foam sheet and the thermoplastic resin laminated foam container of the present invention, the environmental load can be reduced, and the impact resistance and moldability are excellent.

It is sectional drawing which shows an example of the thermoplastic resin laminated foam sheet which concerns on this invention. It is a flow chart which shows an example of the manufacturing process of the polyester resin of a plant origin. It is a flow chart which shows an example of the manufacturing process of the polyester resin of a plant origin. It is a flow chart which shows an example of the manufacturing process of the polyester resin of a plant origin. This is an example of a DSC curve when the temperature (° C.) is plotted on the horizontal axis and the calorific value DSC (mW) is plotted on the vertical axis. It is an enlarged view of the area A of FIG. This is an example of a DSC curve when the temperature (° C.) is plotted on the horizontal axis and the calorific value DSC (mW) is plotted on the vertical axis. It is an enlarged view of the area A'in FIG. 7. It is a perspective view which shows an example of the thermoplastic resin laminated foam container which concerns on this invention. It is a DSC curve of Example 11 when the temperature (° C.) is plotted on the horizontal axis, and the calorific value DSC (mW) is plotted on the vertical axis. It is a DSC curve of Comparative Example 1 when the temperature (° C.) is plotted on the horizontal axis and the calorific value DSC (mW) is plotted on the vertical axis. It is a photograph which shows an example around the tip of the T die before the occurrence of eyebrows. It is a photograph which shows an example around the tip of the T die after the occurrence of a Mayani.

[Thermoplastic resin laminated foam sheet]
The thermoplastic resin laminated foam sheet of the present invention (hereinafter, also simply referred to as “laminated foam sheet”) has a foam layer and a non-foam layer located on one side or both sides of the foam layer.
An embodiment of the laminated foam sheet will be described with reference to the drawings.

The laminated foam sheet 1 of FIG. 1 has a foam layer 10 and a non-foam layer 20 located on one side of the foam layer 10. That is, the laminated foam sheet 1 has the non-foam layer 20 on only one side of the foam layer 10.

_{The thickness T 1} of the laminated foam sheet 1 is, for example, preferably 0.3 to 5.4 mm, more preferably 0.4 to 3.3 mm, and even more preferably 0.6 to 2.7 mm. If the thickness T ₁ of the laminated foam sheet 1 is not less than the above lower limit, the thermoplastic resin laminate foam containers to be described later (hereinafter, simply referred. To as "foam containers") are more enhanced impact resistance. When the thickness T ₁ of the laminated foam sheet 1 is not more than the above upper limit value, the moldability of the laminated foam sheet 1 can be easily improved.
_{The thickness T 1} of the laminated foam sheet 1 is a value obtained by the following method. The thickness of any 10 points in the TD direction (width direction) of the laminated foam sheet 1 is measured with a microgauge. The measured values at 10 points are averaged to obtain the thickness T ₁ of the laminated foam sheet 1.

The open cell ratio of the laminated foam sheet 1 is preferably 20% or less, more preferably 18% or less, still more preferably 16% or less. When the open cell ratio of the laminated foam sheet 1 is not more than the above upper limit value, the impact resistance of the foam container can be further enhanced. The open cell ratio of the laminated foam sheet 1 is determined by the method described in JIS K7138: 2006 "Hard foamed plastic-How to determine the open cell ratio and the closed cell ratio".

The dimensional change rate (hereinafter, also simply referred to as "dimensional change rate") when the laminated foam sheet 1 is heated at 125 ° C. for 2.5 minutes is 40% or less, preferably 30% or less, and 20% or less. More preferably, 15% or less is further preferable, and 10% or less is particularly preferable. When the dimensional change rate of the laminated foam sheet 1 is not more than the above upper limit value, the moldability of the laminated foam sheet 1 can be easily improved. In addition, when the dimensional change rate of the laminated foam sheet 1 is not more than the above upper limit value, the impact resistance of the foam container can be further enhanced.
The smaller the lower limit of the dimensional change rate of the laminated foam sheet 1, the more preferable, but substantially -30% or more, preferably -20% or more, more preferably -10% or more, and -7.5% or more. More preferably, -5% or more is particularly preferable. When the dimensional change rate of the laminated foam sheet 1 is at least the above lower limit value, the impact resistance of the foam container can be further enhanced.

The dimensional change rate of the laminated foam sheet 1 is obtained by the following procedure.
A test piece cut out from the laminated foam sheet 1 into a square having one side of 50 mm in the MD direction (extrusion direction) and a side adjacent to the one side of 50 mm in the TD direction (direction orthogonal to the extrusion direction) is prepared. The test piece is heated in a heating furnace at 125 ° C. for 2.5 minutes. And MD direction length L _m1 of one surface of the test piece, the TD direction of the one surface of the test piece and the length L _t1, measured along the one face. _{Similarly, the length L m2} of the other surface of the test piece (the surface opposite to one surface) in the MD direction and the length _{L t2} of the other surface of the test piece in the TD direction are applied to the other surface. Measure along. In the test piece after heating _{, the shortest length among the above four lengths (L m1} , L _t1 , L _m2 , L _t2 ) is defined as the dimension α1 after heating. The value calculated by the following formula (1) is used as the dimensional change rate of the laminated foam sheet 1. The positive value of the dimensional change rate of the laminated foam sheet 1 means that the dimension α1 after heating is smaller than the dimension of one side before heating. When the dimensional change rate of the laminated foam sheet 1 is a negative value, it means that the dimension α1 after heating is larger than the dimension of one side before heating.
Dimensional change rate (%) = {(dimension of one side before heating 50 (mm))-(dimension after heating α1 (mm))} / (dimension of one side before heating 50 (mm)) × 100 ... (1)

<Foam layer>
The foamed layer 10 is formed by foaming a thermoplastic resin containing a foaming agent.
Examples of the thermoplastic resin include polystyrene-based resins and polyolefin-based resins. From the viewpoint of further improving the moldability of the laminated foam sheet 1, polystyrene-based resin is preferable as the thermoplastic resin.

Examples of the polystyrene-based resin include homopolymers of styrene-based monomers such as styrene, α-methylstyrene, vinyltoluene, chlorostyrene, ethylstyrene, i-propylstyrene, dimethylstyrene, and bromostyrene, or copolymers thereof; A copolymer of a styrene-based monomer as a main component (50% by mass or more) and a styrene-based monomer and a vinyl monomer that can be polymerized thereto: A copolymer of a styrene-based monomer and a rubber component such as butadiene, or a styrene-based monomer. So-called high-impact polystyrene resin (HIPS); etc., which is a homopolymer of the above, a copolymer thereof, a copolymer of a styrene-based monomer and a vinyl monomer, and a mixture or a polymer of a diene-based rubbery polymer. Can be mentioned.
Examples of the vinyl monomer that can be polymerized with the styrene-based monomer include alkyl (meth) acrylates such as methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, and cetyl (meth) acrylate, and (meth) acrylonitrile. Examples thereof include bifunctional monomers such as dimethyl maleate, dimethyl fumarate, diethyl fumarate, ethyl fumarate, divinylbenzene, and alkylene glycol dimethacrylate. These vinyl monomers may be used alone or in combination of two or more.
Here, "(meth) acrylate" represents one or both of "acrylate" and "methacrylate", and "(meth) acrylonitrile" represents one or both of "acrylonitrile" and "methacrylonitrile".
Examples of the diene-based rubber-like polymer include polybutadiene, styrene-butadiene copolymer, ethylene-propylene-non-conjugated diene three-dimensional copolymer, and acrylonitrile-butadiene-styrene copolymer.
These polystyrene-based resins may be used alone or in combination of two or more.

The polystyrene-based resin may be a polystyrene-based resin that is not a recycled raw material, such as a general-purpose polystyrene resin (GPPS), a commercially available polystyrene-based resin, or a polystyrene-based resin newly prepared by a method such as a suspension polymerization method, or a recycled raw material. Polystyrene resin may be used.
The recycled raw material is a used polystyrene resin foam molded product. Recycled raw materials include food packaging trays, fish boxes, cushioning materials for home appliances, etc., which are collected and recycled by a limonene melting method or a heating volume reduction method. In addition, the recycled raw materials that can be used are non-foamed polystyrene resin moldings that are separately collected from home appliances (for example, TVs, refrigerators, washing machines, air conditioners, etc.) and office equipment (for example, copiers, facsimiles, printers, etc.). The body may be crushed, melt-kneaded and repelletized.

The content of the polystyrene-based resin is preferably 60% by mass or more, more preferably 70% by mass or more, further preferably 80% by mass or more, and 90% by mass or more, based on the total mass of the resin contained in the foamed layer 10. It is particularly preferable, and it may be 100% by mass. When the content of the polystyrene-based resin is at least the above lower limit value, the moldability of the laminated foam sheet 1 can be further enhanced.

The polyolefin-based resin is, for example, a homopolymer of an olefin-based monomer such as ethylene or propylene, or a copolymer thereof, or a copolymer of an olefin-based monomer and a vinyl monomer capable of polymerizing the olefin-based monomer as a main component. Examples include polymers. One of these polyolefin resins may be used alone, or two or more thereof may be used in combination.

The resin constituting the foam layer 10 is made of polystyrene such as (meth) acrylic resin, acrylonitrile-styrene copolymer, styrene-butadiene copolymer, and acrylonitrile-butadiene-styrene copolymer in order to enhance impact resistance. It may contain a resin other than the resin and the polyolefin-based resin.
The resin constituting the foam layer 10 may contain a resin other than the polystyrene-based resin and the polyolefin-based resin, such as a polyphenylene ether-based resin, in order to enhance the heat resistance.
Examples of the polyphenylene ether-based resin include poly (2,6-dimethylphenylene-1,4-ether), poly (2,6-diethylphenylene-1,4-ether), and poly (2,6-dichlorophenylene). -1,4-ether) and the like. One of these polyphenylene ether-based resins may be used alone, or two or more thereof may be used in combination.
When the content of the polystyrene-based resin is 60% by mass or more with respect to the total mass of the resin contained in the foam layer 10, the resin other than the polystyrene-based resin (including the polyolefin-based resin) is contained in an amount of 40% by mass or less. You may be.
When the content of the polyolefin-based resin is 60% by mass or more with respect to the total mass of the resin contained in the foam layer 10, a resin other than the polyolefin-based resin (including polystyrene-based resin) is contained in an amount of 40% by mass or less. You may be.

The content of the other resin is preferably 40% by mass or less, more preferably 30% by mass or less, further preferably 20% by mass or less, and 10% by mass or less, based on the total mass of the resin contained in the foam layer 10. It is particularly preferable, and it may be 0% by mass. When the content of the other resin is not more than the above upper limit value, the laminated foam sheet 1 becomes stiff and the molded product can be handled more easily.

Examples of the foaming agent include hydrocarbons such as propane, butane and pentane; halogenated hydrocarbons such as tetrafluoroethane, chlorodifluoroethane and difluoroethane; and inorganic gases such as carbon dioxide, nitrogen and air. Of these, butane is preferable as the foaming agent. As the butane, normal butane or isobutane may be used alone, or normal butane and isobutane may be used in combination at an arbitrary ratio.
These foaming agents may be used alone or in combination of two or more.
The blending amount of the foaming agent is determined in consideration of the type of foaming agent, the apparent density required for the laminated foam sheet 1, and the like. The blending amount of the foaming agent is preferably, for example, 1.0 to 7.0 parts by mass with respect to 100 parts by mass of the total mass of the resin contained in the foam layer 10.

The foam layer 10 may contain components other than the thermoplastic resin and the foaming agent (hereinafter, also referred to as “arbitrary components”). Examples of the optional component include a bubble modifier, a stabilizer, an ultraviolet absorber, an antioxidant, a colorant, a deodorant, a lubricant, a flame retardant, an antistatic agent and the like.
The type of the optional component is determined in consideration of the physical characteristics required for the laminated foam sheet 1. As the optional component, one kind may be used alone, or two or more kinds may be used in combination.

Examples of the bubble adjusting agent include a mixture of inorganic powders such as talc and silica. These bubble modifiers increase the closed cell ratio of the foam layer and facilitate the formation of the foam layer.
Examples of the stabilizer include a calcium-zinc heat stabilizer, a tin heat stabilizer, a lead heat stabilizer and the like.
Examples of the ultraviolet absorber include a cesium oxide-based ultraviolet absorber and a titanium oxide-based ultraviolet absorber.
Examples of the antioxidant include cerium oxide, cerium oxide / zirconia solid solution, cerium hydroxide, carbon, carbon nanotubes, titanium oxide, fullerene and the like.
Examples of the colorant include titanium oxide, carbon black, titanium yellow, iron oxide, ultramarine blue, cobalt blue, fired pigment, metallic pigment, mica, pearl pigment, zinc oxide, precipitated silica, cadmium red and the like.
Examples of the deodorant include silica, zeolite, zirconium phosphate, hydrotalcite calcined product and the like.

The content of the arbitrary component in the foam layer 10 is preferably, for example, 0.05 to 20 parts by mass, more preferably 0.1 to 10 parts by mass, based on 100 parts by mass of the total mass of the resin contained in the foam layer 10. It is preferable, and 0.3 to 5.0 parts by mass is more preferable. When the content of the arbitrary component is at least the above lower limit value, the effect derived from the arbitrary component can be exhibited. When the content of the optional component is not more than the above upper limit value, clogging to the die or the like can be better prevented, and the appearance of the laminated foam sheet 1 can be improved.

When the foaming layer 10 contains a bubble adjusting agent, the content of the bubble adjusting agent is preferably 0.01 to 5.0 parts by mass with respect to 100 parts by mass of the total mass of the resin contained in the foaming layer 10. , 0.02 to 3.0 parts by mass, more preferably 0.03 to 2.0 parts by mass. When the content of the bubble adjusting agent is not more than the above lower limit value, the open cell ratio of the laminated foam sheet 1 can be further reduced. When the content of the bubble adjusting agent is not more than the above upper limit value, clogging to the die or the like can be better prevented, and the appearance of the laminated foam sheet 1 can be improved.

The thickness T ₁₀ of the foam layer 10 may be determined in consideration of application of the laminated foam sheet 1. The thickness _{T 10} of the foam layer 10 is, for example, preferably from 0.3 to 5.0 mm, more preferably 0.4～3.0Mm, more preferably 0.5 to 2.5 mm. If the thickness T ₁₀ of the foam layer 10 is not less than the above lower limit, is increased more the impact resistance of the foam container. If the thickness T ₁₀ of the foam layer 10 is not more than the upper limit, it is increased more the moldability of the foamed sheet 1.
The thickness T ₁₀ of the foam layer 10 is determined by the same methods as the thickness T ₁ of the foam sheet 1.

The basis weight of the foam layer 10 is, for example, preferably 50~600g / ^{m 2,} more preferably 90~500g / ^{m 2,} more preferably 150 and 400 / ^{m 2.} When the basis weight of the foam layer 10 is at least the above lower limit value, the impact resistance of the foam container can be further enhanced. When the basis weight of the foam layer 10 is not more than the above upper limit value, the foam container can be made lighter. In addition, when the basis weight of the foam layer 10 is not more than the above upper limit value, the heating time at the time of heat molding does not become too long, and the productivity of the foam container can be further increased.

The basis weight of the foam layer 10 can be measured by the following method.
Except for both ends 20 mm in the width direction of the foam layer 10, 10 sections of 10 cm × 10 cm are cut out at equal intervals in the width direction, and the mass (g) of each section is measured up to 0.001 g unit. The value obtained by converting the average value of the mass (g) of each section into the mass ^{per 1 m 2 is} defined as the basis weight (g / m ² ) of the foam layer 10.

Apparent density of the foam layer 10 is, for example, preferably 0.050~0.666g / cm ^3, more preferably 0.066~0.500g / cm ^3, more preferably 0.100~0.333g / cm ³ .. When the apparent density of the foam layer 10 is at least the above lower limit value, the impact resistance of the foam container can be further enhanced. When the apparent density of the foam layer 10 is not more than the above upper limit value, the foam container can be made lighter.
The apparent density of the foamed layer 10 is determined by measuring in accordance with JIS K 7222: 2005 "Foam plastics and rubber-How to determine the apparent density".
More specifically, the mass and apparent volume of the test piece of the foam layer 10 cut so as not to change the original cell structure are measured and calculated by the following formula (2).
Apparent density of foam layer 10 (g / cm ³ ) = mass of test piece (g) / apparent volume of test piece (cm ³ ) ... (2)

The foaming ratio of the foamed layer 10 is, for example, preferably 1.5 to 20 times, more preferably 2 to 15 times, still more preferably 3 to 10 times. When the foaming ratio of the foamed layer 10 is at least the above lower limit value, the impact resistance of the foamed container can be further enhanced. When the foaming ratio of the foamed layer 10 is not more than the above upper limit value, the moldability of the laminated foamed sheet 1 can be further enhanced.
The foaming ratio of the foamed layer 10 is a value obtained by dividing 1 by the “apparent density of the foamed layer 10 (g / cm ^3)”.

The average cell diameter of the foam layer 10 is, for example, preferably 80 to 450 μm, more preferably 150 to 400 μm, and even more preferably 200 to 350 μm. When the average cell diameter of the foam layer 10 is at least the above lower limit value, the impact resistance of the foam container can be further enhanced. When the average cell diameter of the foam layer 10 is not more than the above upper limit value, the surface smoothness of the foam container can be further enhanced.
The average cell size of the foam layer 10 can be measured according to the method described in ASTM D2842-69.

<Non-foam layer>
The non-foamed layer 20 is a layer made of a thermoplastic resin and in which bubbles are not substantially formed. In addition, the non-foaming layer 20 is a layer that does not substantially contain a foaming agent.
The non-foamed layer 20 contains a low environmental load resin.
The low environmental load resin of the non-foaming layer 20 is preferably either a biodegradable resin or a plant-derived resin, or one of them.

The Z average molecular weight of the low environmental load resin is preferably 800,000 or less, more preferably 100,000 to 500,000, further preferably 150,000 to 450,000, and particularly preferably 150,000 to 400,000. When the Z average molecular weight of the low environmental load resin is within the above numerical range, the impact resistance of the foam container can be further enhanced.
The method for measuring the Z average molecular weight will be described later.

Examples of the biodegradable resin include polylactic acid resins, linear polyesters of 3-hydroxybutyric acid and 3-hydroxyvaleric acid, polyethers, polyacrylic acids, ethylene-carbon monoxide copolymers, and aliphatic polyesters. − Polyester copolymer, aliphatic polyester-polyester copolymer, aliphatic polyester-aromatic polyester copolymer, aliphatic polyester-polyether copolymer, polymer alloy of starch and modified polyvinyl alcohol, starch and polyethylene Examples thereof include polymer alloys and succinic acid esters. From the viewpoint of enhancing oil resistance, the biodegradable resin is preferably a polylactic acid resin (PLA).

The polylactic acid-based resin is a resin obtained by polymerizing lactic acid by an ester bond. Polylactic acid-based resins are classified as polyester-based resins and are a type of biodegradable resin.
Specifically, the polylactic acid-based resin is a polymer produced from a monomer component containing both or one of D-lactic acid and L-lactic acid.

The polylactic acid-based resin is preferably a polymer of a monomer component consisting of both or only D-lactic acid and L-lactic acid (monomer component). In this case, it is preferable that the content ratio of one of D-lactic acid and L-lactic acid is higher than that of the other. Specific examples thereof include a monomer component composed of optical isomers of lactic acid having the following composition (I) and composition (II) content.

-Composition (I)
The upper limit of the content ratio of D-lactic acid in the total lactic acid (monomer component) is, for example, preferably 5% by mass or less, more preferably 4% by mass or less, and further preferably 3% by mass or less. The lower limit of the content ratio of D-lactic acid is, for example, 0% by mass or more, preferably more than 0% by mass. The lower limit of the content ratio of L-lactic acid in the total lactic acid (monomer component) is, for example, preferably 95% by mass or more, more preferably 96% by mass or more, and further preferably 97% by mass or more. The upper limit of the content ratio of L-lactic acid is, for example, 100% by mass or less, preferably less than 100% by mass.

・ Composition (II)
The upper limit of the content ratio of L-lactic acid in the total lactic acid (monomer component) is, for example, preferably 5% by mass or less, more preferably 4% by mass or less, and further preferably 3% by mass or less. The lower limit of the content ratio of L-lactic acid is, for example, 0% by mass or more, preferably more than 0% by mass. The lower limit of the content ratio of D-lactic acid in the total lactic acid (monomer component) is, for example, preferably 95% by mass or more, more preferably 96% by mass or more, and further preferably 97% by mass or more. The upper limit of the content ratio of D-lactic acid is, for example, 100% by mass or less, preferably less than 100% by mass.

In the case of the monomer component composed of optical isomers of lactic acid having the content ratio of the composition (I), if the content ratio of D-lactic acid is equal to or less than the above upper limit value, the crystallinity of the molded product such as a container is more excellent. It becomes a thing. In the case of a monomer component composed of an optical isomer of lactic acid having the content ratio of composition (II), if the content ratio of L-lactic acid is equal to or less than the above upper limit value, the crystallinity of the molded product such as a container is more excellent. It becomes. The composition (I) is preferable as the monomer component of the polylactic acid-based resin from the viewpoint of productivity and versatility, or from the viewpoint of enhancing oil resistance and moldability.

Further, the monomer component for producing the polylactic acid-based resin can contain a copolymerizable monomer other than lactic acid. Examples of the copolymerizable monomer include polyvalent carboxylic acid, polyhydric alcohol, hydroxycarboxylic acid, lactone and the like. Examples of the polyvalent carboxylic acid include aliphatic dicarboxylic acids such as succinic acid, adipic acid, suberic acid, sebacic acid and dodecanedioic acid, and aromatic dicarboxylic acids such as terephthalic acid. Examples of the polyhydric alcohol include dihydric alcohols such as ethylene glycol, 1,4-butanediol, 1,4-cyclohexanedimethanol, and an ethylene oxide adduct of bisphenol A. Examples of the hydroxycarboxylic acid include glycolic acid, 3-hydroxybutyric acid, 4-hydroxybutyric acid, 2-hydroxyn-butyric acid, 2-hydroxy3,3-dimethylbutyric acid, 2-hydroxy3-methylbutyric acid, and 2-methyllactic acid. , 2-Hydroxy-aliphatic dicarboxylic acid such as 2-hydroxycaproic acid and the like. Examples of the lactone include caprolactone, butyrolactone and valerolactone. These monomers may be used alone or in combination of two or more. The polylactic acid-based resin may also contain, for example, a trace amount of a chain extender such as a diisocyanate compound, an epoxy compound, or an acid anhydride.

From the viewpoint of productivity and versatility, or from the viewpoint of enhancing oil resistance and moldability, preferable polylactic acid-based resins include, for example, REVODE190 (manufactured by Kaisho Biomaterials Co., Ltd.) and HV-6250H (manufactured by Unitika Ltd.). ), Ingeo8052D (manufactured by NatureWorks), Ingeo4032D (manufactured by NatureWorks), and the like. Ingeo4032D (manufactured by NatureWorks) is a polylactic acid-based resin produced from a monomer component containing 98.7% by mass of L-lactic acid and 1.3% by mass of D-lactic acid.

When the biodegradable resin is a polylactic acid-based resin, the Z average molecular weight of the polylactic acid-based resin is preferably 800,000 or less, more preferably 100,000 to 500,000, further preferably 150,000 to 450,000, and even more preferably 150,000 to 40. 10,000 is particularly preferable. When the Z average molecular weight of the polylactic acid-based resin is within the above numerical range, the impact resistance of the foam container can be further enhanced.
The method for measuring the Z average molecular weight will be described later.

Examples of the plant-derived resin include polymers derived from plant raw materials such as sugar cane and corn. "Derived from plant material" includes polymers synthesized or extracted from plant material. Further, for example, "derived from a plant raw material" includes a polymer obtained by polymerizing a monomer synthesized or extracted from a plant raw material. The "monomer synthesized or extracted from a plant material" includes a monomer synthesized from a compound synthesized or extracted from a plant material as a raw material. Plant-derived resins include those in which some of the monomers are "derived from plant materials".
Examples of the plant-derived resin include so-called bio-PET, bio-PE, bio-PP and the like, plant-derived polyester-based resin, plant-derived polyethylene-based resin, plant-derived polypropylene-based resin and the like.

The plant-derived resin will be described by taking polyethylene terephthalate resin (PET) and polyethylene furanoate resin (PEF) as examples.

The PET synthesis reaction is shown in Eq. (1). PET is synthesized by a dehydration reaction of n moles of ethylene glycol (EG) and n moles of terephthalic acid (Benzene-1,4-dioxylic Acid). The stoichiometric mass ratio in this synthetic reaction is ethylene glycol: terephthalic acid = 30:70 (mass ratio). Both ends of the main chain of PET are hydrogen atoms.

［（１）式中、ｎは化学量論係数（重合度）であり、２５０〜１１００の数である。］

[In Eq. (1), n is a stoichiometric coefficient (degree of polymerization), which is a number of 250 to 1100. ]

Ethylene glycol is industrially produced by oxidizing and hydrating ethylene. In addition, terephthalic acid is industrially produced by oxidizing para-xylene.
Here, as shown in FIG. 2, ethylene is obtained by dehydration reaction of plant-derived ethanol (bioethanol), ethylene glycol synthesized from this ethylene (ethylene glycol derived from bioethanol), and terephthal derived from petrochemicals. When synthesizing PET from acid, the PET produced is 30% by mass of plant-derived PET.
Further, as shown in FIG. 3, paraxylene is obtained by dehydration reaction of plant-derived isobutanol (bioisobutanol), and PET is synthesized from terephthalic acid synthesized from this paraxylene and ethylene glycol derived from bioethanol. In this case, the PET produced is 100% by mass of plant-derived PET.

The PEF synthesis reaction is shown in Eq. (2). PEF is synthesized by a dehydration reaction between n moles of ethylene glycol and n moles of furandicarboxylic acid. The stoichiometric mass ratio in this synthetic reaction is ethylene glycol: frangylcarboxylic acid = 33:67 (mass ratio). Both ends of the main chain of PEF are hydrogen atoms.

［（２）式中、ｎは化学量論係数（重合度）であり、２５０〜１１００の数である。］

[In Eq. (2), n is a stoichiometric coefficient (degree of polymerization), which is a number of 250 to 1100. ]

Frangylcarboxylic acid (FDCA) is obtained by, for example, dehydrating plant-derived sugars such as fructose and glucose to obtain hydroxymethylfurfural (HMF) and oxidizing HMF.
As shown in FIG. 4, when both FDCA and ethylene glycol are derived from plants, the produced PEF is 100% by mass of plant-derived PEF.

The content of the low environmental load resin is preferably 90% by mass or less, more preferably 75% by mass or less, further preferably 60% by mass or less, and further preferably 50% by mass, based on the total mass of the resin contained in the non-foamed layer 20. The following is particularly preferable, and 40% by mass or less is most preferable. When the content of the low environmental load resin is not more than the above upper limit value, the impact resistance of the foam container can be further enhanced. The lower limit of the content of the low environmental load resin is preferably, for example, 3% by mass with respect to the total mass of the resin contained in the non-foamed layer 20. The content of the low environmental load resin may be 100% by mass with respect to the total mass of the resin contained in the non-foamed layer 20.

When the non-foaming layer 20 contains a biodegradable resin, the content of the biodegradable resin is preferably 3 to 90% by mass, preferably 5 to 75% by mass, based on the total mass of the resin contained in the non-foaming layer 20. Is more preferable, 10 to 60% by mass is further preferable, 15 to 50% by mass is particularly preferable, and 20 to 40% by mass is most preferable. When the content of the biodegradable resin is at least the above lower limit value, it is easy to reduce the environmental load. When the content of the biodegradable resin is not more than the above upper limit value, the impact resistance of the foam container can be further enhanced.

The resin of the non-foamed layer 20 may contain a resin other than the low environmental load resin (hereinafter, referred to as an arbitrary resin). Examples of the optional resin include general-purpose polystyrene resin (GPPS), high-impact polystyrene resin (HIPS), polyolefin-based resin derived from petrochemicals, polyamide resin, polyethylene terephthalate resin (PET) derived from petrochemicals, and ethylene vinyl alcohol resin. (EVOH) and the like. Examples of the petrochemical-derived polyolefin resin include a petrochemical-derived polyethylene resin, a petrochemical-derived polypropylene resin (PP), a cycloolefin polymer (COP), and a cycloolefin copolymer (COC).
As the optional resin, polystyrene-based resins such as general-purpose polystyrene resin and high-impact polystyrene resin are preferable, and high-impact polystyrene resin is more preferable, from the viewpoint of further enhancing the impact resistance of the foam container.

When the optional resin is a polystyrene resin, the Z average molecular weight of the polystyrene resin is, for example, preferably 800,000 or less, more preferably 100,000 to 650,000, further preferably 150,000 to 600,000, and 150,000 to 550,000. Especially preferable. When the Z average molecular weight of the polystyrene resin is within the above numerical range, the impact resistance of the foam container can be further enhanced. In addition, when the Z average molecular weight of the polystyrene-based resin is within the above numerical range, the fluidity is increased and the low environmental load resin can be dispersed more uniformly. In order to disperse the low environmental load resin more uniformly, it is more preferable that the Z average molecular weight of the polystyrene-based resin is larger than the Z average molecular weight of the low environmental load resin.
The Z average molecular weight of the polystyrene-based resin is determined by the same method as the Z average molecular weight of the low environmental load resin.

When the non-foaming layer 20 contains an arbitrary resin, the content of the optional resin is preferably, for example, 10 to 97% by mass, preferably 25 to 95% by mass, based on the total mass of the resin contained in the non-foaming layer 20. More preferably, 40 to 90% by mass is further preferable, 50 to 85% by mass is particularly preferable, and 60 to 80% by mass is most preferable. When the content of the optional resin is at least the above lower limit value, the impact resistance of the foam container can be further enhanced. When the content of the arbitrary resin is not more than the above upper limit value, a large amount of low environmental load resin can be blended, and the environmental load can be further reduced.
The content of the optional resin may be 0% by mass with respect to the total mass of the resin contained in the non-foamed layer 20.

The non-foamed layer 20 may have a single-layer structure or a multi-layer structure having two or more layers.
When the non-foamed layer 20 has a multilayer structure, a laminated film is used for the non-foamed layer 20. Examples of the laminated film include a single-layer film containing a polystyrene-based resin and a laminated film obtained by dry-laminating another film.

The resin film forming the non-foamed layer 20 may be any of a non-stretched film, a weakly stretched film, a uniaxially stretched film, and a biaxially stretched film. From the viewpoint of easily improving the moldability of the laminated foam sheet 1, the resin film forming the non-foamed layer 20 is preferably a non-stretched film.

As the resin of the non-foaming layer 20, a mixture of a low environmental load resin and an arbitrary resin is preferable. If the resin of the non-foamed layer 20 is a mixture, impact resistance and moldability can be improved while reducing the environmental load.
As the mixture of the low environmental load resin and the optional resin, a mixture of a biodegradable resin and a polystyrene-based resin is more preferable, and a mixture of a polylactic acid-based resin and a polystyrene-based resin is further preferable. The polystyrene-based resin preferably contains a high-impact polystyrene resin.
When the resin of the non-foamed layer 20 is a mixture of a polylactic acid-based resin and a polystyrene-based resin, the mass ratio of the polylactic acid-based resin to the polystyrene-based resin is: polylactic acid-based resin: polystyrene-based resin = 3: 97 to 90. : 10 is preferable, polylactic acid resin: polystyrene resin = 5:95 to 75:25 is more preferable, polylactic acid resin: polystyrene resin = 10:90 to 60:40 is more preferable, and polylactic acid resin: Polystyrene resin = 15:85-50:50 is particularly preferable, and 20:80-40:60 is most preferable.

The Z average molecular weight of the resin of the non-foamed layer 20 is preferably 800,000 or less, more preferably 100,000 to 650,000, further preferably 150,000 to 600,000, and particularly preferably 150,000 to 550,000. When the Z average molecular weight of the resin of the non-foamed layer 20 is within the above numerical range, the impact resistance of the foamed container can be further enhanced.
The Z average molecular weight of the resin of the non-foamed layer 20 is determined by the same method as the Z average molecular weight of the low environmental load resin.

_{The thickness T 20} of the non-foamed layer 20 is determined in consideration of the use of the laminated foamed sheet 1, and is preferably, for example, 20 to 400 μm, more preferably 40 to 300 μm, and even more preferably 60 to 200 μm. If the thickness T ₂₀ of the non-foamed layer 20 is not less than the above lower limit, thereby further improving the impact resistance of the foam container. In addition, the thickness T ₂₀ of the non-foamed layer 20 is not less than the above lower limit, thereby further improving the surface smoothness of the foam container. If the thickness T ₂₀ of the non-foamed layer 20 is not more than the upper limit, it is increased more the formability of the laminated foam sheet 1.
_{The thickness T 20} of the non-foamed layer 20 is obtained by the same method as the _{thickness T 1} of the foamed sheet 1.

In the laminated foam sheet 1, the temperature width of the crystallization heat peak of the non-foamed layer 20 in the second DSC curve measured by using a heat flux differential scanning calorimetry (DSC) device (hereinafter, also referred to as “DSC width”). ) Is 60 ° C. or lower, preferably 55 ° C. or lower, more preferably 50 ° C. or lower, further preferably 40 ° C. or lower, particularly preferably 38 ° C. or lower, and most preferably 36 ° C. or lower. When the DSC width of the non-foamed layer 20 is not more than the above upper limit value, the impact resistance of the foamed container can be further enhanced. The lower limit of the DSC width of the non-foamed layer 20 is not particularly limited, but is substantially 10 ° C. or higher, preferably 15 ° C. or higher, and more preferably 20 ° C. or higher.
The DSC width of the non-foamed layer 20 is adjusted by the type of resin, the composition of the resin, the composition and mixing conditions of the resin composition of the non-foamed sheet, the temperature at which the non-foamed sheet and the foamed sheet are bonded, and the combination thereof. it can.

In the laminated foam sheet 1, the peak top temperature of the crystallization heat peak of the non-foamed layer 20 in the second DSC curve measured by using the DSC device is preferably 125 ° C. or lower, more preferably 120 ° C. or lower, 115 ° C. ° C. or lower is more preferable, 110 ° C. or lower is particularly preferable, and 100 ° C. or lower is most preferable. When the peak top temperature of the non-foamed layer 20 is not more than the above upper limit value, the impact resistance of the foamed container can be further enhanced. The lower limit of the peak top temperature of the non-foamed layer 20 is not particularly limited, but is substantially 85 ° C. or higher, preferably 90 ° C. or higher, and more preferably 95 ° C. or higher.
The peak top temperature of the non-foamed layer 20 can be adjusted by the type of resin, the composition of the resin, and a combination thereof.

Here, the DSC width and the peak top temperature of the non-foamed layer 20 of the laminated foam sheet 1 are obtained by the following procedure.
The non-foaming layer 20 is scraped from the laminated foam sheet 1 with a slicer or a razor to prepare a sample. Using the following measuring device, DSC measurement of this sample is performed under the following measurement conditions. In the DSC curve obtained when the temperature is raised for the second time, the difference between the rising temperature of the crystallization heat peak (exothermic energy peak) and the peak end temperature is defined as the DSC width.
(measuring device)
DSC device: Differential scanning calorimetry device DSC7000X type (manufactured by Hitachi High-Tech Science Corporation).
(Measurement condition)
Sample amount: 5.5 ± 0.5 mg.
Reference (alumina) amount: 5 mg.
Nitrogen gas flow rate: 20 mL / min.
Number of tests: 2.
First temperature rise: The temperature is raised from 30 ° C to 200 ° C at a heating rate of 100 ° C / min, and held at 200 ° C for 10 minutes.
-Set value of the temperature rise start temperature: 30 ° C.
-Set value of the temperature rise end temperature: 200 ° C.
-Set value of heating rate: 100 ° C / min.
-Set value of holding time at the end temperature of temperature rise: 10 minutes.
Cooling method: The sample is taken out from the measuring device, allowed to stand at 23 ° C. for 10 minutes, and then returned to the measuring device at 30 ° C.
Second temperature rise: The temperature is raised from 30 ° C to 200 ° C at a heating rate of 10 ° C / min.
-Set value of the temperature rise start temperature: 30 ° C.
-Set value of the temperature rise end temperature: 200 ° C.
-Heating rate setting value: 10 ° C / min.
(How to create a DSC curve)
From the start of the second temperature rise to the end of the temperature rise, the calorific value DSC is read every 0.2 seconds, and the temperature (° C.) is plotted on the horizontal axis and the calorific value DSC (mW) is plotted on the vertical axis to create a DSC curve. To do.
In the second DSC curve, the temperature at the apex of the crystallization heat peak (exothermic energy peak) is defined as the peak top temperature.

Next, how to obtain the DSC width of the non-foamed layer 20 will be described in detail with reference to FIGS. 5 and 6.
FIG. 5 is a DSC curve of the laminated foam sheet. As shown in FIG. 5, the curve C1 is a DSC curve at the first temperature rise. The curve C2 is a DSC curve at the second temperature rise. On the curve C2, the peak having the peak at 95.2 ° C. is the heat crystallization peak. That is, the peak top temperature _{T p} of the crystallization heat peak is 95.2 ° C.. On the curve C2, the peak having a peak bottom of 164.7 ° C. is the heat of solution peak.

FIG. 6 is an enlarged view of the area A of FIG. As shown in FIG. 6, the heat of crystallization peak has a rising edge and a peak end (falling edge). Let L1 be the baseline on the rising side of the heat of crystallization peak. Let L3 be the baseline on the peak-end side of the heat of crystallization peak. Let L2 be the tangent line drawn on the rising side of the heat peak for crystallization. The tangent line drawn on the peak end side of the heat crystallization peak is defined as L4. At this time, the temperature at the intersection P1 between the baseline L1 and the tangent line L2 is defined as the rising temperature. The temperature at the intersection P2 between the baseline L3 and the tangent L4 is defined as the peak-end temperature.
The DSC width ΔT of the non-foamed layer 20 is given by the following formula (3).
ΔT (° C.) = Peak-end temperature (° C.)-Rise temperature (° C.) ... (3)

Next, the case where the heat crystallization peak has an inflection point will be described.
FIG. 7 is a DSC curve of a laminated foam sheet having a broad heat of crystallization peak. As shown in FIG. 7, the curve C'1 is a DSC curve at the first temperature rise. Curve C'2 is a DSC curve at the second temperature rise. On the curve C'2, the peak having the peak at 116.1 ° C. is the heat crystallization peak. That is, the peak top temperature T _'p crystallization heat peak is 116.1 ° C.. On the curve C'2, the peak having a peak bottom of 164.2 ° C. is the heat of solution peak.

FIG. 8 is an enlarged view of the area A'of FIG. 7. As shown in FIG. 8, the crystallization heat peak has a minimum point on the low temperature side of the peak top temperature T _'p, has an inflection point on the high temperature side. Assuming that the minimum point on the low temperature side is P'1 and the inflection point on the high temperature side is P'2, the temperature at the minimum point P'1 is the rising temperature, and the temperature at the inflection point P'2 is the peak end temperature. is there.
At this time, the DSC width ΔT'of the non-foamed layer is given by the following formula (4).
ΔT'(° C.) = Peak-end temperature (° C.)-Rise temperature (° C.) ... (4)

The non-foamed layer 20 may contain an arbitrary component other than the low environmental load resin and the optional resin.
Examples of the optional component include surfactants, ultraviolet absorbers, antioxidants, colorants, lubricants, flame retardants, antistatic agents and the like. One of these optional components may be used alone, or two or more thereof may be used in combination.

When the non-foaming layer 20 contains a surfactant, the generation of mayani can be suppressed. Here, the Mayani refers to a foreign substance whose main component is a resin deterioration component of a low environmental load resin. Mayani is generated by friction between the low environmental load resin and the slit of the extrusion die (for example, T die, circular die, etc.). When the resin that is the raw material of the non-foamed layer 20 in manufacturing the laminated foam sheet 1 is extruded by the extrusion die, the Mayani is deposited on the tip of the extrusion die with time. When the meshi is deposited on the tip of the extrusion die, it comes into contact with the non-foamed layer 20 and strip-shaped streaks adhere in the resin extrusion direction (flow direction), spoiling the appearance of the non-foamed layer 20 and impairing the appearance of the non-foamed layer 20. It spoils the appearance of. When the non-foamed layer 20 contains a surfactant, the friction between the low environmental load resin and the slit of the extrusion die can be reduced, so that the generation of eyebrows can be suppressed.

12 and 13 show photographs of the vicinity of the tip of the T-die before and after the occurrence of eyebrows.
As shown in FIG. 12, the T die 30 is located in contact with the non-foamed layer 20 of the laminated foam sheet 1. No shavings are observed at the tip 32 of the T-die 30.
On the other hand, in FIG. 13, a plurality of eyebrows 40 are observed at the tip 32 of the T-die 30. If the production of the laminated foam sheet 1 is continued in the state where the meshi 40 is generated in this way, the streaks caused by the meshi 40 adhere to the non-foamed layer 20, and the appearance of the non-foamed layer 20 is impaired. It spoils the appearance of.

Examples of the surfactant include anionic surfactants, nonionic surfactants, cationic surfactants, amphoteric surfactants and the like.
Examples of the anionic surfactant include higher fatty acid (8 to 23 carbon atoms) salts such as zinc stearate, alkyl (8 to 18 carbon atoms) sulfates such as sodium lauryl sulfate, and alkyl (8 to 18 carbon atoms) sulfates such as sodium dodecylbenzenesulfonate. Benzene sulfonate, β-tetrahydroxynaphthalene sulfonate and the like can be mentioned. Examples of the salt include sodium, potassium, magnesium, calcium, barium, lithium, zinc, aluminum, ammonium, triethanolamine and the like.
Examples of the nonionic surfactant include polyhydric alcohol fatty acids (8 to 18 carbon atoms) esters such as stearic acid triglyceride, 12-hydroxystearic acid triglyceride, and pentaerythritol distearate, and higher fatty acids such as ethylene bisstearic acid amide. Examples thereof include amides having 8 to 23 carbon atoms, higher fatty acids (8 to 23 carbon atoms) bisamides, alkylene (1 to 4 carbon atoms) oxide adducts of hardened castor oil, and hardened oils.
Examples of the cationic surfactant include alkyl (8 to 18 carbon atoms) ammonium acetate salts, alkyl (8 to 18 carbon atoms) dimethylbenzylammonium salts, alkyl (8 to 18 carbon atoms) trimethylammonium salts, and dialkyl (8 to 18 carbon atoms) dialkyl (carbon number). 8-18) Dimethylammonium salts, alkyl (8-18 carbon atoms) pyridinium salts, oxyalkylene (1-4 carbon atoms) alkyl (8-18 carbon atoms) amines, polyoxyalkylene (1-4 carbon atoms) alkyl (8 to 18 carbon atoms) amines and the like can be mentioned.
Examples of amphoteric tensides include alkyl (8 to 23 carbon atoms) betaines, fatty acids (8 to 18 carbon atoms) amide propyl betaines, alkyl (8 to 23 carbon atoms) imidazoles, amino acids, and amine oxides. And so on.

As the surfactant, a nonionic surfactant is preferable, and a polyhydric alcohol fatty acid ester is more preferable, because decomposition of the low environmental load resin can be suppressed and compatibility with the low environmental load resin is good. If the decomposition of the low environmental load resin cannot be suppressed, the Z average molecular weight of the low environmental load resin will decrease, and the moldability of the laminated foam sheet and the impact resistance of the laminated foam container will decrease.

The content of the surfactant is preferably 0.01 to 2.0 parts by mass, more preferably 0.05 to 1.5 parts by mass, based on 100 parts by mass of the total mass of the resin contained in the non-foamed layer 20. 0.1 to 1.0 parts by mass is more preferable. The content of the surfactant is preferably 0.01 to 10 parts by mass, more preferably 0.01 to 7 parts by mass, still more preferably 0.3 to 5 parts by mass with respect to 100 parts by mass of the low environmental load resin. .. When the content of the surfactant is at least the above lower limit value, the generation of mayani can be suppressed more satisfactorily. When the content of the surfactant is not more than the above upper limit value, the decrease in impact resistance of the foam container can be better suppressed.
The content of the surfactant can be measured by the following measuring method.

<< Method of measuring the content of surfactant in the non-foamed layer >>
The non-foaming layer 20 is sampled from the laminated foamed sheet 1 using a slicer or a razor. A plurality of samples are prepared in the shape of a square having a side of 5 mm. For the prepared sample, the content of the surfactant is measured by the following method.
When collecting the non-foaming layer from the laminated foam container, the non-foaming layer is collected from the bottom surface of the laminated foam container using a slicer or a razor in the same manner as collecting from the laminated foam sheet 1, and used as a sample.

<Pretreatment>
(I) Place 1 g of the sample in a container for pretreatment, and freeze and pulverize the sample with the following device under the following conditions to make the sample into powder.
-Freezing and crushing equipment: Freezing and crushing equipment JFC-300 manufactured by Nippon Analytical Industry Co., Ltd.
-Crushing conditions: Liquid nitrogen immersion pre-cooling time = 10 min, shaking crushing time = 30 min.
(Ii) Weigh 0.05 g of the obtained powdery sample, add 5 mL of THF (tetrahydrofuran), and apply ultrasonic waves with a frequency of 38 kHz for 15 minutes with the following ultrasonic generator to extract the surfactant. .. Then, this extract is filtered through a non-aqueous 0.20 μm chromatodisc (GL Sciences Co., Ltd.) to obtain a filtrate.
(Super sound generator and extraction conditions)
Ultrasonic generator: SonoCleaner 200D, a desktop ultrasonic cleaner manufactured by KAIJO CORPORATION.
Sound wave frequency: 38 kHz.
Extraction time: 15 minutes.
Extraction temperature: Room temperature (22 ° C.).

<Measurement of surfactant content>
Using the filtrate obtained in the above pretreatment, the content of the surfactant in the non-foaming layer is measured with the following measuring device under the following measuring conditions.
(measuring device)
GPC (Gel Permeation Chromatography) Equipment: Ultra-high performance liquid chromatograph Prominence 20A manufactured by Shimadzu Corporation.
Guard column: Shimadzu GLC Co., Ltd. Shima-pack GPC 800P (4.6 mm ID x 10 mm) x 1 piece.
column:
Shimadzu GLC Shima-pack GPC 801 (8 mm ID x 300 mm) x 2 pieces.
Shimadzu GLC Shima-pack GPC 803 (8 mm ID x 300 mm) x 1 piece.
Shimadzu GLC Shima-pack GPC 804 (8 mm ID x 300 mm) x 1 piece.
(Measurement condition)
Column temperature: 40 ° C.
Detector temperature: 40 ° C.
Pump injection temperature: Room temperature (25 ° C).
Solvent: THF (tetrahydrofuran).
Flow rate: 1.0 mL / min.
Execution time: 45 min.
Data interval: 500 msec.
Injection volume: 100 μL.
Detector: RI: RID-10A.

<Creation of calibration curve>
A calibration curve corresponding to each surfactant is required to measure the content of the surfactant. Here, as an example, preparation of a standard solution for stearic acid triglyceride will be described.
As the standard product of stearic acid triglyceride, "Rikemar (registered trademark) VT-50 (manufactured by RIKEN Vitamin Co., Ltd.)" is used, and 100 mg of stearic acid triglyceride is dissolved in 20 mL of THF to obtain a standard solution of 5,000 ppm.
The obtained standard solution is further diluted with THF to prepare standard solutions of 500 ppm, 200 ppm, 100 ppm, and 50 ppm.
The calibration curve is obtained by injecting 100 μL of the prepared standard solution of each concentration into the GPC apparatus and preparing an approximate line from the peak area obtained after the measurement.

When the non-foaming layer 20 contains an arbitrary component, the content of the optional component in the non-foaming layer 20 is, for example, 0.05 to 20 with respect to 100 parts by mass of the total mass of the resin contained in the non-foaming layer 20. By mass is preferable, 0.1 to 10 parts by mass is more preferable, and 0.3 to 5.0 parts by mass is further preferable. When the content of the arbitrary component is at least the above lower limit value, the effect derived from the arbitrary component can be exhibited. When the content of the optional component is not more than the above upper limit value, clogging to the die or the like can be better prevented, and the appearance of the laminated foam sheet 1 can be improved.

[Manufacturing method of laminated foam sheet]
The laminated foam sheet is manufactured by a conventionally known manufacturing method.
As a method for manufacturing the laminated foam sheet 1, for example, a foamed sheet to be a foamed layer 10 and a non-foamed sheet to be a non-foamed layer 20 are manufactured, and the non-foamed sheet and the foamed sheet are stacked in this order. (Thermocompression bonding method) can be mentioned. In the thermocompression bonding method, the temperature at the time of thermocompression bonding is preferably equal to or higher than the melting point of the low environmental load resin.
Examples of the method for producing the laminated foam sheet 1 include a method in which a non-foamed sheet and a foamed sheet are laminated in this order and each layer is bonded with an adhesive (bonding method).
As a method for producing the laminated foam sheet 1, a method of extruding a resin which is a raw material of the non-foamed layer 20 onto the surface of the foamed sheet by a T die (T die method), and a method of coextruding to provide the non-foamed layer 20 on the foamed layer 10. Examples thereof include a method of obtaining a laminated body (coextrusion method). The temperature of the resin that is the raw material of the non-foamed layer 20 when extruded is preferably equal to or higher than the melting point of the low environmental load resin.

As a method for producing a non-foamed sheet, a known method for producing a non-foamed sheet can be adopted.
As a method for producing a non-foamed sheet, resin pellets used as a raw material for the non-foamed sheet may be melt-mixed in advance to form pellets (mixed pellets) again, and the non-foamed sheet may be produced using the resin pellets. It may be subjected to the T-die method or the coextrusion method. Alternatively, a non-foamed sheet may be manufactured without producing mixed pellets, or a non-foamed layer may be formed by a T-die method or a coextrusion method. From the viewpoint of further enhancing the dispersibility of the low environmental load resin and further enhancing the impact resistance of the foam container, it is preferable to form the non-foamed layer using the mixed pellets.

As a method for producing a foamed sheet, a known method for producing a foamed sheet can be adopted.
First, the raw material composition containing the resin and other components and the foaming agent are supplied to an extruder to be melted and kneaded to obtain a mixture. The temperature at which the resin is melted (melting temperature: set temperature) is preferably, for example, 180 to 220 ° C. When the melting temperature is at least the above lower limit value, the resin and other raw materials can be uniformly mixed. When the melting temperature is not more than the above upper limit value, the decomposition of the resin can be suppressed.

[Foam container]
The foam container of the present invention is formed by molding the above-mentioned laminated foam sheet of the present invention. The foam container has a non-foam layer on both the inner surface and / or the outer surface.
The foam container preferably has a bottom wall portion and a side wall portion that rises from the peripheral edge of the bottom wall portion. Examples of such a container include a tray having a perfect circular shape, an elliptical shape, a semicircular shape, a polygonal shape, a fan shape, etc., a bowl-shaped container, a container having a bottomed cylindrical shape or a bottomed square cylinder shape, and a container for natto. Various containers such as containers with lids; lids and the like attached to the container body can be mentioned.
As the use of these foam containers, for example, food products are preferable.

The thickness of the bottom wall portion and the side wall portion of the foam container (hereinafter, may be referred to as “wall thickness”) is determined in consideration of the application and the like, and is preferably 0.3 to 5.0 mm, for example, 0. 4 to 3.0 mm is more preferable, and 0.5 to 2.5 mm is further preferable. When the wall thickness of the foam container is at least the above lower limit value, the impact resistance of the foam container can be further enhanced. When the wall thickness of the foam container is not more than the above upper limit value, the foam container can be made lighter.
The apparent density of the foamed layer in the foamed container is determined in consideration of the application and the like, and tends to be smaller than the apparent density of the foamed layer 10 in the laminated foamed sheet 1, but it is almost the same.
Further, the average cell diameter of the foam layer in the foam container tends to be larger than the average cell diameter of the foam layer 10 in the laminated foam sheet 1, but it is almost the same.

The foam layer of the foam container is the same as the foam layer 10 of the laminated foam sheet 1 described above.
The non-foaming layer of the foam container is the same as the non-foaming layer 20 of the laminated foam sheet 1 described above.

In the foam container, the temperature width of the crystallization heat peak of the non-foaming layer (hereinafter, also referred to as “DSC width”) in the second DSC curve measured by using the DSC device is 60 ° C. or less, 55. ° C. or lower is preferable, 50 ° C. or lower is more preferable, 40 ° C. or lower is further preferable, 38 ° C. or lower is particularly preferable, and 36 ° C. or lower is most preferable. When the DSC width of the non-foamed layer is not more than the above upper limit value, the impact resistance of the foamed container can be further enhanced. The lower limit of the DSC width of the non-foamed layer is not particularly limited, but is substantially 10 ° C. or higher, preferably 15 ° C. or higher, and more preferably 20 ° C. or higher.

In the foam container, the peak top temperature of the crystallization heat peak of the non-foaming layer in the second DSC curve measured using the DSC device is preferably 125 ° C. or lower, more preferably 120 ° C. or lower, and 115 ° C. or lower. More preferably, 110 ° C. or lower is particularly preferable, and 100 ° C. or lower is most preferable. When the peak top temperature of the non-foamed layer is not more than the above upper limit value, the impact resistance of the foamed container can be further enhanced. The lower limit of the peak top temperature of the non-foamed layer is not particularly limited, but is substantially 85 ° C. or higher, preferably 90 ° C. or higher, and more preferably 95 ° C. or higher.

The DSC width of the non-foaming layer in the foam container is obtained by the same method as the DSC width of the non-foaming layer 20 of the laminated foam sheet 1 described above.
The peak top temperature of the non-foaming layer in the foam container is obtained by the same method as the peak top temperature of the non-foaming layer 20 of the laminated foam sheet 1 described above.

The dimensional change rate (hereinafter, also simply referred to as “dimensional change rate”) when the foam container is heated at 125 ° C. for 2.5 minutes is 40% or less, preferably 30% or less, and more preferably 20% or less. , 15% or less is more preferable, and 10% or less is particularly preferable. When the dimensional change rate of the foam container is not more than the above upper limit value, the impact resistance of the foam container can be further enhanced.
The smaller the lower limit of the dimensional change rate of the foam container is, the more preferable, but it is substantially -30% or more, preferably -20% or more, more preferably -10% or more, still more preferably -7.5% or more. , -5% or more is particularly preferable. When the dimensional change rate of the foam container is at least the above lower limit value, the impact resistance of the foam container can be further enhanced.

The dimensional change rate of the foam container is obtained by the following procedure.
Prepare a test piece cut into a square of 50 mm square from the bottom wall of the foam container. The test piece is heated in a heating furnace at 125 ° C. for 2.5 minutes. _{The length L d1} of one side of one surface of _{the test piece and the length L d2 of the} side orthogonal to the side of the length _{L d1} of one surface of the test piece are measured along one surface. _{Similarly, the length L d11 in the} direction along the side of _{the length L d1} of the other surface of the test piece (the surface opposite to one surface) _{and the side of the length L d11} of the other surface of the test piece. _{The lengths L d12} of the orthogonal sides are measured along the other surface. In the test piece after heating _{, the shortest length among the above four lengths (L d1} , L _d2 , L _d11 , L _d12 ) is defined as the dimension α2 after heating. The value calculated by the following formula (5) is used as the dimensional change rate of the foam container. The positive value of the dimensional change rate of the foam container means that the dimension α2 after heating is smaller than the dimension of one side before heating. When the dimensional change rate of the foam container is a negative value, it means that the dimension α2 after heating is larger than the dimension of one side before heating.
Dimensional change rate (%) = {(dimension of one side before heating 50 (mm))-(dimension after heating α2 (mm))} / (dimension of one side before heating 50 (mm)) × 100 ... (5)

An embodiment of the foam container of the present invention will be described with reference to the drawings.
As shown in FIG. 9, the foam container 100 is a bowl-shaped container having a perfect circular shape in a plan view. The foam container 100 has a circular bottom wall 110 and a side wall 120 rising from the peripheral edge of the bottom wall 110. The foam container 100 is formed with an opening 130 surrounded by the upper end of the side wall 120. The side wall 120 extends outward toward the upper end. The opening 130 surrounded by the upper end of the side wall 120 is a perfect circle in a plan view. The bottom wall 110 is formed of a convex portion 112 that is a perfect circle in a plan view and is convex in the direction of the opening 130, and an annular concave portion 114 that surrounds the convex portion 112.
The foam container 100 is suitably used as a container for foods such as storing instant noodles and pouring hot water into it.

The foam container 100 of the present embodiment is a perfect circle in a plan view, but the present invention is not limited to this. The plan-view shape of the foam container may be elliptical or polygonal.

The foam container may have a non-foaming layer only on the inner surface, or may have a non-foaming layer only on the outer surface. Further, the foam container may have a non-foam layer on both the inner surface and the outer surface.

[Manufacturing method of foam container]
As a method for manufacturing a foam container, for example, a laminated foam sheet is heated to form a secondary foam sheet (secondary foaming step), which is sandwiched between a female mold and a male mold (molding step) and molded (thermoforming). Method).
The secondary foaming step is a step of heating the laminated foamed sheet to further foam the foamed layer of the laminated foamed sheet to form the secondary foamed layer.
Examples of the device for heating the laminated foam sheet in the secondary foaming step include a heating furnace having heaters at the top and bottom of the furnace.
The heating temperature in the secondary foaming step is, for example, preferably 200 to 600 ° C, more preferably 300 to 550 ° C. When the heating temperature is within the above numerical range, it is easy to adjust the secondary foaming layer to a desired foaming ratio.
The expansion ratio of the secondary foam layer is preferably 6 to 20 times, for example.

The molding step is a step of sandwiching a secondary foam sheet between a female mold and a male mold to obtain a container having an arbitrary shape.
The temperature of the molding die in the molding step is not particularly limited, but is preferably 50 to 150 ° C, more preferably 60 to 130 ° C, for example. When the temperature of the molding die is equal to or higher than the above lower limit value, the number of fine bubbles near the boundary between the foamed layer and the non-foamed layer increases, and the printing characteristics can be further improved. When the temperature of the molding die is not more than the above upper limit value, it is possible to prevent the secondary foam sheet from melting.

As described above, according to the laminated foam sheet of the present embodiment, since the non-foamed layer contains the low environmental load resin, the environmental load can be reduced.
In addition, according to the laminated foam sheet of the present embodiment, since the temperature range of the crystallization heat peak of the non-foamed layer in the second DSC curve is 60 ° C. or less, the impact resistance of the foam container can be further enhanced.
Further, according to the laminated foam sheet of the present embodiment, the dimensional change rate when heated at 125 ° C. for 2.5 minutes is 40% or less, so that the laminated foam sheet is excellent in moldability.

The present invention is not limited to the above-described embodiment.
In the above-described embodiment, the non-foamed layer is provided on only one side of the foamed layer, but the present invention is not limited to this, and the non-foamed layer may be provided on both sides of the foamed layer.
By having non-foamed layers on both sides of the foamed layer, the environmental load can be further reduced.
In addition, by having the non-foamed layers on both sides of the foamed layer, the impact resistance of the foamed container can be further enhanced.
Further, by having the non-foaming layer on both sides of the foaming layer, the surface of the non-foaming layer can be printed, and the design of the foaming container can be further enhanced.
A printing layer may be provided on the surface of the non-foaming layer, and a non-foaming layer may be further provided on the surface of the printing layer.

Hereinafter, the present invention will be described in detail with reference to Examples, but the present invention is not limited to the following description.
The raw materials used in this example are as follows.

[Raw materials used]
(Low environmental load resin)
-REVODE190: Polylactic acid resin, manufactured by Kaisei Biomaterials Co., Ltd.
-HV-6250H: Polylactic acid resin, manufactured by Unitika Ltd.
Ingeo4032D: Polylactic acid-based resin, manufactured by NatureWorks, a polylactic acid-based resin produced from a monomer component containing Z average molecular weight = 310,000, L lactic acid 98.7% by mass, and D lactic acid 1.3% by mass.
(Polystyrene resin)
-HRM52N: General-purpose polystyrene resin, manufactured by Toyo Styrene Co., Ltd.
-E785N: High impact polystyrene resin, manufactured by Toyo Styrene Co., Ltd.
-E641N: High impact polystyrene resin, manufactured by Toyo Styrene Co., Ltd.
(Nonion surfactant)
-VT-50: Trade name "Rikemar (registered trademark) VT-50", stearic acid triglyceride, melting point 66.8 ° C., manufactured by Riken Vitamin Co., Ltd.
-OHG: Trade name "Dywax OHG", 12-hydroxystearic acid triglyceride, melting point 80-90 ° C, manufactured by Dainichi Chemical Industry Co., Ltd.
EB-FF: ethylene bisstearic acid amide, melting point 141-146 ° C., manufactured by Kao Corporation.
-EPL-6: Pentaerythritol distearate, melting point 50-60 ° C, manufactured by Dainichi Chemical Industry Co., Ltd.
-EPL-8: Mixture of higher fatty acid amide and higher fatty acid bisamide, melting point 145 ° C, manufactured by Dainichi Chemical Industry Co., Ltd.
-EPL-15: A mixture of hydrogenated oil, higher fatty acid bisamide and higher fatty acid monoglyceride, melting point 70 ° C., manufactured by Dainichi Chemical Industry Co., Ltd.
(Anionic surfactant)
-ZF: Zinc stearate, melting point 120-126 ° C, manufactured by Dainichi Chemical Industry Co., Ltd.

[Examples 1 to 8, 10 to 21, 24 to 25, Comparative Examples 1 to 2, Reference Example 1]
<Manufacturing of foam sheet 1>
Melt mass flow rate (MFR) 1.8 g / 10 min polystyrene resin (trade name "G0002", manufactured by PS Japan Corporation) 100 parts by mass as the main raw material, talc masterbatch (trade name "DSM1401A") as the bubble conditioner, 1.0 part by mass of Toyo Styrene Co., Ltd. was mixed, placed in a tandem extruder, and melt-kneaded. Butane gas is press-fitted into this melt at a predetermined position and kneaded, and then a cylindrical foam is extruded from a circular die having a diameter of 170 mm, cooled by a predetermined mandrel, cut into a sheet, and wound. Was done. The thickness of the obtained foamed sheet was 1.75 mm, the basis weight was 220 g / m ² , and the apparent density was 0.126 g / cm ³ .

<Mixing of resin composition for non-foamed layer>
Low environmental load resin, polystyrene resin, high impact polystyrene resin, and surfactant were blended in the blending amounts shown in Tables 1 to 3, and premixed with a mixing drum.
Examples described as "biaxial" in the kneading process of Tables 1-3, was charged resin were preliminarily mixed at above Toshiba Machine Co., Ltd. biaxial extruder TEM26SS, cylinder temperature 200 ° C., shear rate 89 s ^{- It is shown that the strands were melt-mixed in 1 to} form strands, and the strands were cooled and then led to a pelletizer to form pellets. The examples described as "blend" in the kneading methods in Tables 1 to 3 indicate that the mixture was put into the following extruder (T die) in a premixed state without passing through the twin-screw extruder. Examples described as "blend coextrusion" in the kneading methods in Tables 1 to 3 include the raw material hopper for the inner layer of the extruder (T die) below and the outer layer in a premixed state without passing through the twin-screw extruder. It is shown that the outer layer 1 is located on one surface of the inner layer and the outer layer 2 is located on the other surface of the inner layer by coextruding the inner layer and the outer layer into a raw material hopper. The examples described as "-" in the kneading methods in Tables 1 to 3 indicate that the non-foamed sheet prepared in advance was thermocompression bonded without premixing.

<Manufacturing of laminated foam sheet 1>
Tables 1 to 3 of the extruder (T die) show the resin composition obtained by mixing the foamed sheet obtained in the above <Production of foamed sheet 1> with the above <Mixing of the resin composition for the non-foamed layer>. It was discharged from the opening of the slit width shown at the shear rate shown in Tables 1 to 3, adjusted so that the ^{basis weight was 120 g / m 2, and laminated.} When laminating, adjust the air gap (distance from the opening of the AG and T dies to the lamination on the foam sheet) shown in Tables 1 to 3, and make the T die opening 50 mm from the position where the foam sheet is laminated. The temperature of the thermoplastic resin (film) at the approaching position was measured with a non-contact temperature measuring device.
The thickness of the obtained laminated foam sheet was 1.84 mm, the basis weight was 340 g / m ² , and the apparent density was 0.185 g / cm ³ .

<Evaluation of adhesion of eyebrows>
In the above <Manufacturing of Laminated Foam Sheet 1>, every time after the resin composition is discharged (from the start of extrusion), it is visually confirmed whether or not the tip of the T-die has a shaving and adherence. The resin adhesion was evaluated based on the following evaluation criteria. The results are shown in Tables 1-3. The evaluation of adhesion of eyebrows is "S" or "A", and the continuous productivity of the laminated foam sheet is excellent. In Reference Example 1, since the non-foamed layer does not contain a low environmental load resin, the evaluation of adhesion to the eyebrows was not performed (indicated by "-" in the table).
"Evaluation criteria"
S: No adhesion of eyebrows is observed even after 8 hours have passed since the start of extrusion.
A: No adhesion of Mayani is observed even after 4 hours have passed since the start of extrusion, but adhesion of Mayani is observed after 8 hours.
B: No adhesion of eyebrows is observed 2 hours after the start of extrusion, but adhesion of eyebrows is observed 4 hours after the start of extrusion.
C: No adhesion of eyelid is observed even after 1 hour has passed since the start of extrusion, but adhesion of eyelid is observed after 2 hours.

[Example 9]
<Manufacturing of foam sheet 2>
In the first extruder, 100 parts by mass of polystyrene resin (trade name "G0002", manufactured by PS Japan Corporation) with melt mass flow rate (MFR) 1.8 g / 10 min as the main raw material, and talc masterbatch as a bubble conditioner ( The trade name "DSM1401A" and 1.0 part by mass of Toyo Styrene Co., Ltd. were mixed and placed in a tandem extruder for melt kneading. Butane gas was press-fitted into the melt at a predetermined position and kneaded (foam layer molten resin).
On the other hand, EVA resin (trade name "Novatec", manufactured by Mitsubishi Chemical Co., Ltd.) was blended in 100% by mass in the second extruder, placed in a single-screw extruder, and melt-kneaded (adhesive layer molten resin).
Next, the foamed layer molten resin and the adhesive layer molten resin are supplied to the merging mold, these molten resins are merged, and the foam layer and the adhesive layer are laminated in this order from the inside to the outside to form a cylindrical foam. The body was co-extruded from a circular die having a diameter of 170 mm, cooled with a predetermined mandrel, cut into pieces, formed into a sheet, and wound. The thickness of the obtained foamed sheet was 1.77 mm, the basis weight was 239 g / m ² , and the apparent density was 0.135 g / cm ³ .

<Manufacturing of laminated foam sheet 2>
A low environmental load resin is discharged from the slit width opening shown in Table 1 of the extruder (T die) to the foamed sheet obtained in the above <Manufacturing of foamed sheet 2> at the shear rate shown in Table 1 to tsubo. The amount was adjusted to 120 g / m ² and laminated. When laminating, the air gap (AG) shown in Table 2 is adjusted, and the temperature of the thermoplastic resin (film) at a position 50 mm from the position where it is laminated on the foam sheet and close to the T-die opening is measured by non-contact temperature measurement. Measured with a vessel.
The thickness of the obtained laminated foam sheet was 1.84 mm, the basis weight was 340 g / m ² , and the apparent density was 0.185 g / cm ³ . Similar to the above <Manufacturing of laminated foam sheet 1>, evaluation of adhesion of eyebrows was performed. The results are shown in Table 1.

[Examples 22 to 23]
<Manufacturing of laminated foam sheet 3>
100% by mass of the low environmental load resin was melt-kneaded by the first extruder. On the other hand, a low environmental load resin and a high impact polystyrene resin are blended in the blending amounts shown in Table 3, premixed with a mixing drum, and then the premixed resin composition is put into a second extruder and melt-kneaded. It was. At the single pipe portion of the first extruder and the second extruder, the resin melt of the second extruder is merged with the resin melt of the first extruder so as to be an outer layer, and the slit widths shown in Table 3 are formed. It was discharged from the T-die opening at the shear rate shown in Table 3 and ^{adjusted so that the basis weight was 120 g / m 2} to obtain a non-foamed layer of 2 types and 3 layers (blend coextrusion). A non-foamed layer co-extruded by blending was laminated on the foamed sheet obtained in the above <Manufacturing of foamed sheet 1>. When laminating, the air gap (AG) shown in Table 3 is adjusted, and the temperature of the thermoplastic resin (film) at a position 50 mm from the position where it is laminated on the foam sheet and close to the T-die opening is measured by non-contact temperature measurement. Measured with a vessel.
The thickness of the obtained laminated foam sheet was 1.84 mm, the basis weight was 340 g / m ² , and the apparent density was 0.185 g / cm ³ .
In Examples 22 to 23, the outer layer 1 is located on one surface of the inner layer, and the outer layer 2 is located on the other surface of the inner layer. : 2: 1. The outer layer 1 and the outer layer 2 of Example 22 were made of 100% by mass of high-impact polystyrene resin, and the inner layer was made of 100% by mass of low environmental load resin. The blending amount of the resin of the non-foamed layer of the 2 types and 3 layers of Example 22 was 50% by mass of the low environmental load resin and 50% by mass of the high impact polystyrene resin. The outer layer 1 and the outer layer 2 of Example 23 were a mixture of 30% by mass of the low environmental load resin and 70% by mass of the high impact polystyrene resin, and the inner layer was 100% by mass of the low environmental load resin. The blending amount of the resin of the non-foamed layer of the 2 types and 3 layers of Example 23 was 65% by mass of the low environmental load resin and 35% by mass of the high impact polystyrene resin. In Examples 22 to 23, since the outer layer 1 and the outer layer 2 of the non-foamed layer contained the high-impact polystyrene resin and the shavings were less likely to occur, the shaving adhesion evaluation was not performed (indicated by "-" in the table).

[Comparative Example 3]
160 PLA films (thickness 25 μm, trade name “Palgreen LC”, manufactured by Mitsui Chemicals Tohcello Co., Ltd.) coated with EVA resin as an adhesive layer on the foamed sheet obtained in the above <Manufacturing of foamed sheet 2>. It was heat-laminated on one side with a heat roll at ° C. and a speed of 14 m / min. Since the laminated foam sheet was manufactured by the laminating method, the evaluation of the adhesion of the eyebrows was not performed (indicated by "-" in the table).

<Manufacturing of foam containers>
After heating the laminated foam sheet obtained in <Manufacturing of laminated foam sheet 1> and <Manufacturing of laminated foam sheet 2> in a heater tank at 270 ° C. for 15 seconds, a male plug type and a female designed to have a clearance of 2 mm. The sheet was brought into close contact with the mold of the mold. Next, the plug mold and the cavity mold were closed for 3 seconds and vacuum-compressed air-molded to obtain a foam container having an opening size of φ190 mm, a bottom size of φ170 mm, and a height of 50 mm in a circular shape in a plan view.
At this time, a laminated foam sheet was installed so that the surface of the non-foam layer was in contact with the male plug type, and a foam container was manufactured. In Comparative Example 3, molding was difficult, and the side wall portion immediately below the opening was torn and wrinkles were drawn.

For the laminated foam sheet and foam container obtained in each example, the Z average molecular weight ( _MZ ) of the low environmental load resin in the non-foamed layer, the DSC width of the non-foamed layer, and the peak of the non-foamed layer shown in the following evaluation methods. The top temperature, dimensional change rate, hot water deformation, oil resistance, moldability, and impact resistance were evaluated. The results are shown in Tables 1-3. In the table, "-" in the column of the resin content of the non-foamed layer indicates that the resin is not contained. In the table, "-" in the column of nonionic surfactant and anionic surfactant indicates that the surfactant is not contained. In the table, "heat lami" in the column of laminating conditions of Comparative Example 3 indicates that the non-foamed sheet was heat-laminated and laminated on the foamed sheet. In the table, "-" in the column of the laminated foam sheet and the foam container of Reference Example 1 indicates that the item was not measured.

_{[Measurement of Z average molecular weight (MZ} ) of low environmental load resin in non-foamed layer]
The bottom surface of the laminated foam sheet and the foam container obtained in each example was scraped off with a slicer or a razor, and only the non-foam layer was collected as a sample. For this sample, the low environmental load resin was separated from the sample by pretreatment under the following measurement conditions, and the Z average molecular weight ( _MZ ) of the low environmental load resin in the non-foamed layer was measured. Each sample was cut into a square shape having a length of 5 mm and a width of 5 mm and used.

<Measurement conditions>
(Preprocessing)
(I) 100 mg of the sample was weighed into a 50 mL centrifuge tube, 20 mL of methyl ethyl ketone (MEK) was added, and the mixture was stirred for 24 hours.
(Ii) The stirred dispersion was separated by a centrifuge at 3500 rpm for 30 minutes, and the supernatant was separated into a 50 mL beaker.
(Iii) 5 mL of MEK was added to the above-mentioned centrifuge tube, washed with an ultrasonic cleaner for 5 minutes, and mixed well.
(Iv) This mixed solution was separated by a centrifuge at 3500 rpm for 30 minutes, and the supernatant was removed.
(V) The above (iii) to the above (iv) were repeated twice, and then filtered through a 200 mesh wire mesh to obtain an insoluble matter.
(Vi) The obtained insoluble material was evaporated to dryness at room temperature (25 ° C.).
(Vii) 20 mg of the insoluble matter that had been evaporated to dryness was weighed, 2.5 mL of chloroform was added, and the mixture was dispersed with an immersion time of 6.0 ± 1.0 hr. Then, this dispersion was filtered through a non-aqueous 0.45 μm syringe filter (manufactured by Shimadzu LLC Co., Ltd.).

Using the filtrate obtained by the above pretreatment, the Z average molecular weight of the low environmental load resin in the non-foamed layer was measured with the following measuring device under the following measuring conditions.
(measuring device)
GPC device: HLC-8320GPC (built-in RI detector / UV detector) manufactured by Tosoh Corporation.
Guard column: TOSOH TSK Guard column HXL-H (6.0 mm ID x 4 cm) x 1 piece.
Column (reference): Resistance tube (inner diameter 0.1 mm x 2 m) x 2 pieces.
Column (sample): TOSOH TSKgel GMHXL (7.8 mm ID x 30 cm) x 2 pieces.
(Measurement condition)
Column temperature: 40 ° C.
Detector temperature: 40 ° C.
Pump injection part temperature: 40 ° C.
Solvent: Chloroform.
Flow rate (reference): 0.5 mL / min.
Flow rate (sample): 1.0 mL / min.
Execution time: 28 min.
Data accumulation time: 10 to 28 min.
Data interval: 500 msec.
Injection volume: 50 μL.
Detector: RI.

(Standard polystyrene sample for calibration curve)
Calibration curve for standard polystyrene samples from Showa Denko Co., Ltd. Product name "STANDARD SM-105" and "STANDARD SH-75", weight average molecular weight _M W is 5,620,000,3,120,000, Those of 1,250,000, 442,000, 131,000, 54,000, 20,000, 7,590, 3,450, and 1,320 were used.
The standard polystyrenes for the calibration curve are A (5,620,000, 1,250,000, 131,000, 20,000, 3,450) and B (3,120,000, 442,000, 54,000, It was divided into 7,590, 1,320) groups. A was weighed (2 mg, 3 mg, 4 mg, 4 mg, 4 mg) and then dissolved in 30 mL of chloroform. B was weighed (3 mg, 4 mg, 4 mg, 4 mg, 4 mg) and then dissolved in 30 mL of chloroform.
The standard polystyrene calibration curve was obtained by injecting 50 μL of each of the prepared A and B solutions and preparing a calibration curve (third-order formula) from the retention time obtained after the measurement. The Z average molecular weight was calculated using the calibration curve.

[Measurement of DSC width and peak top temperature]
The bottom surface of the laminated foam sheet and the foam container obtained in each example was scraped off with a slicer or a razor, and only the non-foam layer was collected as a sample. This sample was subjected to DSC measurement using the following measuring device under the following measuring conditions. In the DSC curve obtained when the temperature was raised a second time, the difference between the rising temperature of the crystallization heat peak and the peak end temperature was defined as the DSC width. The temperature at the apex of the heat crystallization peak was defined as the peak top temperature.
(measuring device)
DSC device: Differential scanning calorimetry device DSC7000X type (manufactured by Hitachi High-Tech Science Corporation).
(Measurement condition)
Sample amount: 5.5 ± 0.5 mg.
Reference (alumina) amount: 5 mg.
Nitrogen gas flow rate: 20 mL / min.
Number of tests: 2.
First temperature rise: The temperature is raised from 30 ° C to 200 ° C at a heating rate of 100 ° C / min, and held at 200 ° C for 10 minutes.
-Set value of the temperature rise start temperature: 30 ° C.
-Set value of the temperature rise end temperature: 200 ° C.
-Set value of heating rate: 100 ° C / min.
-Set value of holding time at the end temperature of temperature rise: 10 minutes.
Cooling method: The sample is taken out from the measuring device, allowed to stand at 23 ° C. for 10 minutes, and then returned to the measuring device at 30 ° C.
Second temperature rise: The temperature is raised from 30 ° C to 200 ° C at a heating rate of 10 ° C / min.
-Set value of the temperature rise start temperature: 30 ° C.
-Set value of the temperature rise end temperature: 200 ° C.
-Heating rate setting value: 10 ° C / min.
(How to create a DSC curve)
From the start of the second temperature rise to the end of the temperature rise, the calorific value DSC is read every 0.2 seconds, and the temperature (° C.) is plotted on the horizontal axis and the calorific value DSC (mW) is plotted on the vertical axis to create a DSC curve. did.

FIG. 10 shows a DSC curve (second DSC curve) obtained when the temperature of the laminated foam sheet of Example 11 is raised for the second time. The DSC width in the second DSC curve of Example 11 was 55.1 ° C., and the peak top temperature was 105.2 ° C.

FIG. 11 shows the second DSC curve of the laminated foam sheet of Comparative Example 1. The DSC width in the second DSC curve of Comparative Example 1 was 62.0 ° C., and the peak top temperature was 140.1 ° C.

[Measurement of dimensional change rate of laminated foam sheet]
The dimensional change rate of the laminated foam sheet obtained in each example was determined by the following procedure.
A test piece obtained by cutting the laminated foam sheet in the MD direction (extrusion direction) 50 mm and the TD direction (direction orthogonal to the extrusion direction) 50 mm was prepared. The test piece was heated in a heating furnace at 125 ° C. for 2.5 minutes. And MD direction length L _m1 of one surface of the test piece, the TD direction of the one surface of the test piece and the length L _t1, measured along the one face. _{Similarly, the length L m2} of the other surface of the test piece (the surface opposite to one surface) in the MD direction and the length _{L t2} of the other surface of the test piece in the TD direction are applied to the other surface. Measured along. In the test piece after heating _{, the shortest length among the above four lengths (L m1} , L _t1 , L _m2 , L _t2 ) was defined as the dimension α1 after heating. The value calculated by the following formula (1) was used as the dimensional change rate of the laminated foam sheet.
Dimensional change rate (%) = {(dimension of one side before heating 50 (mm))-(dimension after heating α1 (mm))} / (dimension of one side before heating 50 (mm)) × 100 ... (1)

In the test piece after heating, the length L _{m1 in} the MD direction of one surface and the length L _m2 in the MD direction of the other surface, and the shorter length was defined as the dimension α3 in the MD direction after heating. .. The value calculated by the following formula (6) was taken as the dimensional change rate in the MD direction of the laminated foam sheet. The positive value of the dimensional change rate in the MD direction of the laminated foam sheet means that the dimension α3 after heating is smaller than the dimension of one side before heating. The negative value of the dimensional change rate in the MD direction of the laminated foam sheet means that the dimension α3 after heating is larger than the dimension of one side before heating.
Dimensional change rate (%) in the MD direction = {(dimension of one side before heating 50 (mm))-(dimension after heating α3 (mm))} / (dimension of one side before heating 50 (mm)) × 100 ... (6)

In the test piece after heating, the length L _{t1 in} the TD direction of one surface and the length L _t2 in the TD direction of the other surface, and the shorter length was defined as the dimension α4 in the TD direction after heating. .. The value calculated by the following formula (7) was taken as the dimensional change rate in the TD direction of the laminated foam sheet. The positive value of the dimensional change rate in the TD direction of the laminated foam sheet means that the dimension α4 after heating is smaller than the dimension of one side before heating. The negative value of the dimensional change rate in the TD direction of the laminated foam sheet means that the dimension α4 after heating is larger than the dimension of one side before heating.
Dimensional change rate (%) in the TD direction = {(dimension of one side before heating 50 (mm))-(dimension after heating α4 (mm))} / (dimension of one side before heating 50 (mm)) × 100 ... (7)

[Measurement of dimensional change rate of foam container]
The dimensional change rate of the foam container obtained in each example was determined by the following procedure.
A test piece cut into a 50 mm square from the bottom wall of the foam container was prepared. The test piece was heated in a heating furnace at 125 ° C. for 2.5 minutes. _{The length L d1} of one side of one surface of _{the test piece and the length L d2 of the} side orthogonal to the side of the length _{L d1} of one surface of the test piece were measured along one surface. _{Similarly, the length L d11 in the} direction along the side of _{the length L d1} of the other surface of the test piece (the surface opposite to one surface) _{and the side of the length L d11} of the other surface of the test piece. _{The lengths L d12} of the orthogonal sides were measured along the other surface. In the test piece after heating _{, the shortest length among the above four lengths (L d1} , L _d2 , L _d11 , L _d12 ) was defined as the dimension α2 after heating. The value calculated by the following formula (5) was taken as the dimensional change rate of the foam container.
Dimensional change rate (%) = {(dimension of one side before heating 50 (mm))-(dimension after heating α2 (mm))} / (dimension of one side before heating 50 (mm)) × 100 ... (5)

[Evaluation of hot water supply deformation]
Hot water at 90 ° C. was poured into the foam container obtained in each example, and the container was covered with an acrylic plate to prevent steam from escaping. The amount of boiling water to be poured was 300 mL. After 5 minutes had passed since the hot water was poured, the poured hot water was discharged and the appearance of the foam container was visually confirmed. The hot water supply deformation was evaluated based on the following evaluation criteria.
"Evaluation criteria"
5 points: No warping of the flange or swelling of the side wall is observed.
4 points: There is no warp of the flange, but the container body swelling is slightly seen.
3 points: Warping of the flange and swelling of the container are slightly observed.
2 points: Warping of the flange and swelling of the container body are slightly observed, and the bottom surface of the container is also swelling.
1 point: The warp of the flange and the swelling of the body of the container are large, and the bottom surface of the container is also swelling.

[Evaluation of oil resistance on the surface of the non-foamed layer of the laminated foam sheet]
MCT oil (trade name, Nisshin Oillio Group Co., Ltd.) containing medium-chain fatty acid triglyceride (MCT) having 7 to 11 carbon atoms heated to 93 ° C. on the surface of the non-foamed layer of the laminated foamed sheet obtained in each example. The above oil was wiped off after dropping 15 mL of (manufactured by) and leaving it for 5 minutes. The state of the laminated foamed sheet after wiping off the oil was visually confirmed, and the oil resistance of the surface of the non-foamed layer of the laminated foamed sheet was evaluated based on the following evaluation criteria.
"Evaluation criteria"
5 points: The appearance can be maintained without white spots or melting of the non-foamed layer.
4 points: There are a few white spots on the non-foamed layer that look like oil has soaked into them.
3 points: The non-foamed layer is not melted, but the foamed layer is impregnated with oil.
2 points: The non-foamed layer is melted, the oil swells in the foamed layer, and the strength is reduced.
1 point: There are holes in the non-foamed layer and the foamed layer.

[Evaluation of oil resistance of foam container]
Seal the opening of the foam container obtained in each example, open the lid only on the hot water supply part, and MCT oil containing medium chain fatty acid triglyceride (MCT) with 7 to 11 carbon atoms (trade name, Nisshin Oillio Group Co., Ltd.) (Manufactured) was added dropwise in an amount of 15 mL, and boiling water at 90 ° C. was poured into the mixture. After closing and sealing the hot water supply part, it was left for 5 minutes. After that, the poured boiling water was discharged, and the appearance of the foam container was visually confirmed. The oil resistance of the foam container was evaluated based on the following evaluation criteria.
"Evaluation criteria"
5 points: The appearance can be maintained without white spots or melting of the non-foamed layer.
4 points: There are a few white spots on the non-foamed layer that look like oil has soaked into them.
3 points: The non-foamed layer is not melted, but the foamed layer is impregnated with oil.
2 points: The non-foamed layer is melted, the oil swells in the foamed layer, and the strength is reduced.
1 point: Holes were opened in the non-foamed layer and the foamed layer, and the hot water, which was the content, leaked out.

[Evaluation of moldability]
The appearance of the foam container obtained in each example was visually observed, and the moldability was evaluated based on the following evaluation criteria.
"Evaluation criteria"
5 points: Molded without any problem.
1 point: There is a tear or a pull-in wrinkle just below the opening of the foam container.

[Evaluation of impact resistance 1]
400 g of water was put into the foam container obtained in each example, and the opening was sealed. This container was dropped onto a concrete surface from a height of 1.0 m in an environment of 23 ° C., and the presence or absence of damage to the container was visually confirmed. A test was conducted on 10 foam containers in each example, and the impact resistance was evaluated based on the following evaluation criteria.
"Evaluation criteria"
5 points: Number of damaged containers 0 to 2.
4 points: Number of damaged containers 3-5.
3 points: Number of damaged containers 6-7.
2 points: Number of damaged containers 8-9.
1 point: Dozens of damaged containers.

[Evaluation of impact resistance 2]
400 g of water was put into the foam container obtained in each example, and the opening was sealed. This container was dropped onto a concrete surface from a height of 0.8 m in an environment of 23 ° C., and the presence or absence of damage to the container was visually confirmed. A test was conducted on 10 foam containers in each example, and the impact resistance was evaluated based on the following evaluation criteria.
"Evaluation criteria"
5 points: Number of damaged containers 0 to 2.
4 points: Number of damaged containers 3-5.
3 points: Number of damaged containers 6-7.
2 points: Number of damaged containers 8-9.
1 point: Dozens of damaged containers.

[Comprehensive evaluation of impact resistance]
Of the above [Impact resistance evaluation 1] and [Impact resistance evaluation 2], the one with the higher score was used as the overall evaluation score for impact resistance.

[Comprehensive evaluation]
Of the evaluation of hot water supply deformation, the evaluation of the oil resistance of the surface of the non-foamed layer of the laminated foam sheet, the evaluation of the oil resistance of the foam container, the evaluation of moldability, and the comprehensive evaluation of impact resistance, the evaluation with the worst evaluation (the most). The evaluation with a low score) was judged as the overall evaluation. The evaluation result of the comprehensive evaluation was represented by any of 5 points to 1 point.

In Examples 1 to 25 to which the present invention was applied, the overall evaluation was any of 5 points to 2 points.
On the other hand, in Comparative Examples 1 and 2 in which the DSC widths of the laminated foam sheet and the foam container were outside the range of the present invention, the evaluation of impact resistance was "1 point". In Comparative Example 3 in which the dimensional change rate was outside the range of the present invention, the evaluation of the hot water supply deformation and the evaluation of the moldability were "1 point". In Reference Example 1 which does not contain a low environmental load resin, the evaluation of oil resistance was "1 point".

From these results, it was found that the thermoplastic resin laminated foam sheet and the thermoplastic resin laminated foam container of the present invention can reduce the environmental load and are excellent in impact resistance and moldability.

1 Thermoplastic resin laminated foam sheet (laminated foam sheet)
10 Foam layer 20 Non-foam layer

Claims (25)

It has a foamed layer and a non-foamed layer located on one side or both sides of the foamed layer.
The non-foamed layer contains a low environmental load resin and has a low environmental load resin.
The temperature width of the crystallization heat peak of the non-foamed layer in the second DSC curve measured using a heat flux differential scanning calorimetry device is 60 ° C. or less.
A thermoplastic resin laminated foam sheet having a dimensional change rate of 40% or less when heated at 125 ° C. for 2.5 minutes. The thermoplastic resin laminated foam sheet according to claim 1, wherein the low environmental load resin is both or one of a biodegradable resin and a plant-derived resin. The thermoplastic resin laminated foam sheet according to claim 1 or 2, wherein the non-foamed layer contains a polystyrene resin. The thermoplastic resin laminated foam sheet according to claim 3, wherein the polystyrene-based resin contains a high-impact polystyrene resin. The thermoplastic resin laminated foam according to any one of claims 1 to 4, wherein the content of the low environmental load resin is 90% by mass or less with respect to the total mass of the resin contained in the non-foamed layer. Sheet. The thermoplastic resin laminated foam sheet according to any one of claims 1 to 5, wherein the temperature range of the crystallization heat peak of the non-foamed layer in the second DSC curve is 50 ° C. or less. The thermoplastic resin laminated foam sheet according to any one of claims 1 to 6, wherein the peak top temperature of the crystallization heat peak is 125 ° C. or lower. The thermoplastic resin laminated foam sheet according to any one of claims 1 to 7, wherein the low environmental load resin contains a biodegradable resin, and the biodegradable resin is a polylactic acid-based resin. The thermoplastic resin laminated foam sheet according to claim 8, wherein the polylactic acid-based resin has a Z average molecular weight of 800,000 or less. The thermoplastic resin laminated foam sheet according to claim 8 or 9, wherein the content of the biodegradable resin is 3 to 90% by mass with respect to the total mass of the resin contained in the non-foamed layer. Claimed that the non-foaming layer contains a surfactant, and the content of the surfactant is 0.01 to 2.0 parts by mass with respect to 100 parts by mass of the total mass of the resin contained in the non-foaming layer. Item 2. The thermoplastic resin laminated foam sheet according to any one of Items 1 to 10. The thermoplastic resin laminated foam sheet according to claim 11, wherein the surfactant is a nonionic surfactant. A thermoplastic resin laminated foam container obtained by molding a thermoplastic resin laminated foam sheet having a foam layer and a non-foam layer located on one side or both sides of the foam layer.
Having the non-foamed layer on both the inner surface and / or the outer surface,
The non-foamed layer contains a low environmental load resin and has a low environmental load resin.
The temperature width of the crystallization heat peak of the non-foamed layer in the second DSC curve measured using a heat flux differential scanning calorimetry device is 60 ° C. or less.
A thermoplastic resin laminated foam container having a dimensional change rate of 40% or less when heated at 125 ° C. for 2.5 minutes. The thermoplastic resin laminated foam container according to claim 13, wherein the low environmental load resin is both or one of a biodegradable resin and a plant-derived resin. The thermoplastic resin laminated foam container according to claim 13 or 14, wherein the non-foamed layer contains a polystyrene resin. The thermoplastic resin laminated foam container according to claim 15, wherein the polystyrene-based resin contains a high-impact polystyrene resin. The thermoplastic resin laminated foam according to any one of claims 13 to 16, wherein the content of the low environmental load resin is 90% by mass or less with respect to the total mass of the resin contained in the non-foamed layer. container. The thermoplastic resin laminated foam container according to any one of claims 13 to 17, wherein the temperature range of the crystallization heat peak of the non-foamed layer in the second DSC curve is 50 ° C. or less. The thermoplastic resin laminated foam container according to any one of claims 13 to 18, wherein the peak top temperature of the crystallization heat peak is 125 ° C. or lower. The thermoplastic resin laminated foam container according to any one of claims 13 to 19, wherein the low environmental load resin contains a biodegradable resin and the biodegradable resin is a polylactic acid-based resin. The thermoplastic resin laminated foam container according to claim 20, wherein the polylactic acid-based resin has a Z average molecular weight of 800,000 or less. The thermoplastic resin laminated foam container according to claim 20 or 21, wherein the content of the biodegradable resin is 3 to 90% by mass with respect to the total mass of the resin contained in the non-foamed layer. Claimed that the non-foaming layer contains a surfactant, and the content of the surfactant is 0.01 to 2.0 parts by mass with respect to 100 parts by mass of the total mass of the resin contained in the non-foaming layer. Item 3. The thermoplastic resin laminated foam container according to any one of Items 13 to 22. The thermoplastic resin laminated foam container according to claim 23, wherein the surfactant is a nonionic surfactant. The thermoplastic resin laminated foam container according to any one of claims 13 to 24, which is a container for food.

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