Foamed paper laminate, method for producing the same, and foamed paper container.

Abstract

FOAMED PAPER LAMINATE, METHOD FOR PRODUCING THE SAME, AND FOAMED PAPER CONTAINER. A foamed paper laminate is provided having: a foamed paper with a thermoplastic resin layer (A), a paper substrate and a foamed thermoplastic resin layer (B) in this order; and a printed layer formed on the surface of the foamed thermoplastic resin layer (B) of the foamed paper, in which the number of foamed cells per unit area of ​​the foamed thermoplastic resin layer (B) is 1,000 cells / 1 cm2 or more, the printed layer includes a binder resin containing a polyurethane resin, and the residual percentage of the printed layer after immersion for 30 minutes in ethanol at 25°C is 50% by mass or more.

Description

1 / 83 Foamed paper laminate, method for producing the same, and FOAM PAPER CONTAINER Technical Field

[0001] One embodiment of the present invention relates to a foamed paper laminate and a method for producing the same. Furthermore, another embodiment of the present invention relates to a foamed paper container provided with the foamed paper laminate. Background of the Art

[0002] Foam containers are widely used as containers for food products, including hot or cold liquids, due to their excellent thermal insulation properties. Therefore, foam containers are indispensable for products commonly called cup noodles, where instant noodles like ramen, udon, and soba, contained in a container, can be consumed in just a few minutes by simply pouring an appropriate amount of boiling water over them. Styrene foam containers and foam-lined paper containers are known as foam containers for cup noodles, but in recent years foam-lined paper containers have been attracting attention from the perspective of environmental impact and safety.

[0003] A foamed paper container is produced using a foamed paper material with a paper substrate and a thermoplastic resin layer that foams due to heating during the container's production and forms a heat-insulating layer. Typically, a printed layer including a printing pattern, such as a decorative pattern, a company name, and a barcode, is formed on the container. Petition 870220063643, dated 07 / 19 / 2022, page 21 / 108 2 / 83 surface of a foamed paper container (foamed paper material). It is therefore desirable that the printed layer have excellent adaptability to foam formation so as not to impede foam formation when the thermoplastic resin layer of the foamed paper material foams due to heating and forms the heat-insulating layer. Furthermore, it is desirable that the surface (printed surface) of the printed layer after the thermoplastic resin layer has foamed be smooth, free from cracks and bubbles and the like, and have an excellent external appearance. In addition, it is desirable that the printed surface be excellent in terms of various types of resistance, such as abrasion resistance and thermal resistance, which are necessary during the production of the container.

[0004] Conventionally, oil-based inks, such as oil-based gravure inks and oil-based flexographic inks, have been used to form the printed layer of a foamed paper container. Oil-based inks generally contain an organic solvent, such as toluene, for solubility and drying of a binder resin. However, in recent years, regulations regarding the use of organic solvents have become more stringent from the point of view of environmental impact and occupational health and safety, and consequently, there is an increased demand for water-based inks. Therefore, in the field of food product containers used for cup noodles and similar products, the development of foamed paper laminates with a printed layer formed with water-based inks is underway, and these can be suitablely used as a material for foamed paper containers. Petition 870220063643, dated 07 / 19 / 2022, p. 22 / 108 3 / 83

[0005] For example, Patent Document 1 discloses a water-based flexographic ink for a foam cup as an ink for forming a printed layer of a foamed paper laminate, in which the water-based flexographic ink contains a binder resin, a pigment, and water, and the binder resin contains a polyurethane resin. Furthermore, Patent Document 2 discloses that the foaming of a foam layer is suppressed within a predetermined range by a water-based ink-coated portion (printed layer). The water-based ink disclosed in Patent Document 2 contains a dye and a binder resin and contains 30% by mass or more of a urethane-based resin with a glass transition point of -20°C to 30°C in the solids content of the binder resin.Furthermore, Patent Document 3 discloses a water-based paint containing, as a binder resin, an acrylic-based resin, an acrylic urethane copolymer resin, a styrenomaleic acid copolymer resin, or a polyurethane resin. Prior art documents Patent Documents.

[0006] Patent Document 1: Publication of Unexamined Japanese Patent Application No. 2018-058955.

[0007] Patent Document 2: International Publication No. 2018 / 066031.

[0008] Patent Document 3: Publication of Unexamined Japanese Patent Application No. 2011-068381. Summary of the invention Technical problem

[0009] The thermal insulation properties of a foamed paper container depend mainly on Petition 870220063643, dated 07 / 19 / 2022, page 23 / 108 4 / 83 foaming properties of a thermoplastic resin layer that constitutes a foamed layer (thermal insulation layer) in a foamed paper laminate. However, the foaming properties of the thermoplastic resin layer increase during thermal processing and, consequently, external appearance defects such as cracks and bubbles are more likely to occur on the surface of the printed layer formed in the thermoplastic resin layer. Therefore, it is desirable that the printed layer be able to uniformly suppress foam formation in such a way that external appearance defects such as cracks and bubbles can be avoided and, at the same time, not impede the foam formation of the thermoplastic resin layer.

[00010] However, compared to conventional oil-based inks used to form the printed layer of a foamed paper laminate, when water-based inks are used it is difficult to obtain the desired foam adaptability, abrasion resistance, and thermal resistance in the printed layer, and the quality of the foamed paper laminate easily drops. Furthermore, it is difficult to uniformly suppress the foaming of the thermoplastic resin layer through the printed layer. Therefore, the external appearance of the printed surface after the foaming of the thermoplastic resin layer (hereinafter referred to as the external foam appearance) is prone to defects such as cracks and bubbles. In addition, since solvents such as ethanol for disinfection are widely used in the food industry, chemical resistance, such as ethanol resistance of the printed layer, is also necessary.

[00011] However, generally, a printed layer Petition 870220063643, dated 07 / 19 / 2022, page 24 / 108 5 / 83 formed with water-based inks is highly hydrophilic and therefore it is difficult to obtain excellent ethanol resistance. For example, even when a printed layer is formed using the water-based inks disclosed in Patent Documents 1 to 3, it is difficult to provide a foamed paper laminate that can fully satisfy the various characteristics required in the food packaging industry, and further improvements are desired.

[00012] Therefore, considering the aforementioned circumstances, one embodiment of the present invention provides a foamed paper laminate with a printed layer formed using a water-based ink, wherein the printed layer has excellent adaptability to foam formation without hindering the foam formation of a thermoplastic resin layer during thermal processing, and the surface of the printed layer has excellent external foaming appearance, abrasion resistance, thermal resistance, and ethanol resistance, and one embodiment of the present invention also provides a method for producing the foamed paper laminate. Solution to the problem

[00013] In order to solve the above problem, the inventors diligently studied the relationship between the foaming properties of a thermoplastic resin layer during thermal processing and the ability of a printed layer to suppress foaming. As a result, it was found that by forming the printed layer using an aqueous ink composition containing a specific binder resin, favorable results can be obtained in terms of the foaming properties of the resin layer. Petition 870220063643, dated 07 / 19 / 2022, page 25 / 108 6 / 83 thermoplastic and the characteristics of the printed surface, such as the external appearance of foam formation, abrasion resistance, thermal resistance, and ethanol resistance, leading to the conclusion of the present invention. In other words, the present invention relates to the following embodiments, but is not limited to them and includes several embodiments.

[00014] One embodiment relates to a foamed paper laminate having: foamed paper with a thermoplastic resin layer (A), a paper substrate and a foamed thermoplastic resin layer (B) in this order; and a printed layer formed on the surface of the foamed thermoplastic resin layer (B) of the foamed paper, wherein the number of foamed cells per unit area of ​​the foamed thermoplastic resin layer (B) is 1,000 cells / 1 cm2 or more, the printed layer includes a binder resin containing a polyurethane resin, and the residual percentage of the printed layer after immersion for 30 minutes in ethanol at 25°C is 50% by mass or more.

[00015] In foamed paper laminate, the binder resin preferably has a tensile strength of 0.1 mPa to 50 mPa at an elongation percentage of 50 to 4,000%. The binder resin preferably has a glass transition temperature (Tg) of -100°C to 0°C.

[00016] In foamed paper laminate, the printed layer preferably has a film thickness of 0.5 to 5.0 μm.

[00017] In foamed paper laminate, the printed layer preferably includes a cured product consisting of: a binder resin containing a polyurethane resin. Petition 870220063643, dated 07 / 19 / 2022, page 26 / 108 7 / 83 with an acidity index of 1 to 100 mg KOH / g; and at least one of a carbodiimide-based curing agent and one of an isocyanate-based curing agent.

[00018] In foamed paper laminate, the printed layer preferably has a plurality of layers, and the outermost layer is preferably a transparent layer.

[00019] In foamed paper laminate, the foamed thermoplastic resin layer (B) preferably has a thickness of 500 to 950 μm.

[00020] An embodiment refers to a foamed paper container supplied with the foamed paper laminate of the embodiment above.

[00021] One embodiment refers to a method for producing a foamed paper laminate having: a foamed paper with a thermoplastic resin layer (A), a paper substrate and a foamed thermoplastic resin layer (B) in this order; and a printed layer formed on a surface of the foamed thermoplastic resin layer (B) of the foamed paper, a number of foamed cells per unit area of ​​the foamed thermoplastic resin layer (B) being 1,000 cells / 1 cm2 or more, and a residual percentage of the printed layer after immersion for 30 minutes in ethanol at 25°C being 50% by mass or more, the method for producing the foamed paper laminate including: To prepare the foamed paper material, have, in order, the thermoplastic resin layer (A), the paper substrate, and a foamed thermoplastic resin layer (B0) that has a lower melting point than the Petition 870220063643, dated 07 / 19 / 2022, page 27 / 108 8 / 83 layer of thermoplastic resin (A) and foams due to the fact that it is heated; Prepare an aqueous paint composition containing a binder resin containing a polyurethane resin and water; forming the printed layer by applying the aqueous ink composition onto a surface of the foamed thermoplastic resin layer forming the (Bo) layer of foamed paper material; and forming the foamed thermoplastic resin layer (B) by heating the foamed paper material with the printing layer and thus causing the foamed thermoplastic resin layer (B0) of foamed paper material to foam.

[00022] In the production method, an aqueous paint composition containing: a binder resin containing a polyurethane resin with an acidity index of 1 to 100 mg KOH / g; water; and at least one of a carbodiimide-based curing agent and an isocyanate-based curing agent is preferably prepared as the aqueous paint composition.

[00023] In the production method, the printed layer preferably has a plurality of layers, and the outermost layer is preferably a transparent layer.

[00024] In the production method, the foamed thermoplastic resin layer (B0) preferably has a film thickness of 40 to 150 μm.

[00025] The disclosure of this application relates to the subject matter described in Japanese Patent Application No. 2020006574 filed on January 20, 2020, all of which is incorporated herein by Petition 870220063643, dated 07 / 19 / 2022, page 28 / 108 Reference 9 / 83. Effects of the Invention

[00026] According to the present invention, it is possible to provide a foamed paper laminate with a printed layer, which has excellent adaptability to foam formation without hindering the foam formation of a thermoplastic resin layer during thermal processing, and is excellent in terms of external foam appearance, abrasion resistance, thermal resistance and ethanol resistance, and it is also possible to provide a method for producing the foamed paper laminate. Furthermore, according to the present invention, it is possible to provide a foamed paper container provided with the foamed paper laminate. Brief description of the drawings

[00027] FIG. 1 is a perspective view illustrating an example of the structure of a foamed paper container provided with a foamed paper laminate constituting an embodiment.

[00028] FIG. 2 is a schematic cross-sectional view illustrating an enlarged view of part of the foamed paper container shown in FIG. 1 (the part indicated by the reference character I). Description of the Modalities

[00029] The embodiments of the present invention are described more specifically below. However, the present invention is not limited to the embodiments described below and includes several embodiments. <1> Foamed paper laminate

[00030] One embodiment refers to a foamed paper laminate. The foamed paper laminate has: foamed paper Petition 870220063643, dated 07 / 19 / 2022, p. 29 / 108 10 / 83 with a thermoplastic resin layer (A), a paper substrate and a foamed thermoplastic resin layer (B) in this order; and a printed layer formed on the surface of the foamed thermoplastic resin layer (B) of the foamed paper, the number of foamed cells per unit surface area of ​​the foamed thermoplastic resin layer (B) is 1,000 cells / 1 cm2 or more, the printed layer includes a binder resin containing a polyurethane resin, and the residual percentage of the printed layer after immersion for 30 minutes in ethanol at 25°C is 50% by mass or more.

[00031] Regarding the number of foamed cells per unit surface area of ​​the thermoplastic resin foamed layer (B) (hereinafter also referred to as foamed layer (B)), a higher number means that smaller bubbles are present in the foamed layer (B), and a lower number means that larger bubbles are present in the foamed layer (B). When the bubbles present in the foamed layer (B) become larger, external appearance defects such as cracks and bubbles on the printed surface are likely to occur.

[00032] In one embodiment, the number of foam cells per unit surface area of ​​the foamed layer (B) is preferably 1,000 cells / 1 cm2 or more, and more preferably 1,250 cells / 1 cm2 or more. When the number of foamed cells is consistent with the above ranges, it is easy to obtain an excellent external appearance of foam without cracks and bubbles in the printed layer formed in the foamed layer (B). The upper limit for the number of foam cells is not particularly restricted; however, in one embodiment, the number of foamed cells can be 1,600 Petition 870220063643, dated 07 / 19 / 2022, page 30 / 108 11 / 83 cells / 1 cm2 or less from the point of view of production conditions and so on.

[00033] Here, the number of foam cells per unit area means a value calculated as the number of independent cells (bubbles) per 1 cm2 counting the number of independent cells that are present within an interval demarcated by a given length in the vertical and horizontal directions (XY) on the surface of the foamed layer (B). The number of independent cells is determined by removing the printed layer from the foamed paper laminate using a solvent to expose the surface of the foamed layer (B) and then observing the surface of the foamed layer (B) using an optical microscope.

[00034] The thickness of the foamed layer (B) is preferably 500 μm or more, and more preferably 630 μm or more, from the point of view of thermal insulation properties. If the thickness of the foamed layer (B) is 500 μm or more, it is easy to continuously hold the container with bare hands, even when the foamed paper laminate is formed in a cup-shaped container and hot water of approximately 100°C is poured into the container. However, from the point of view of resource conservation, it is preferable to use the minimum amount of resin possible. Furthermore, from the point of view of thermal insulation properties, it is not necessary for the foamed layer (B) to be so thick as to result in excessive quality as a thermal insulation layer. Therefore, as for the thickness of the foamed layer (B), 950 μm or less is preferred, 900 μm or less is more preferred, and 800 μm is highly preferred.

[00035] From the viewpoints mentioned above, in a Petition 870220063643, dated 07 / 19 / 2022, p. 31 / 108 In 12 / 83 embodiment, the thickness of the foamed layer (B) is preferably 500 to 950 μm, more preferably 500 to 900 μm, and even more preferably 500 to 800 μm. The thickness of the foamed layer (B) is determined by observing a cross-section of the foam paper laminate using an optical microscope photograph and measuring the height from the upper surface of the paper substrate to the lower surface of the printed layer.

[00036] In the foamed paper laminate of the embodiment above, the foamed layer (B) of the foamed paper means the state after the thermoplastic resin layer has foamed due to heating. In other words, the foamed layer (B) is formed due to a non-foamed thermoplastic resin layer (foamed thermoplastic resin layer forming layer (B0)) serving as a precursor being heated and transformed into foam. In one embodiment, to form the foamed paper laminate, it is possible to use a foamed paper material (foamed paper before heating) having, in the following order, a thermoplastic resin layer (A), a paper substrate, and a foamed thermoplastic resin layer forming layer (B0) that has a melting point lower than the thermoplastic resin layer (A) and foams due to heat treatment. The foamed paper material may be composed of a material that is publicly known in the technical field in question.The constituent materials of foamed paper laminate are described in more detail below. (Paper substrate).

[00037] The paper substrate that constitutes the foamed paper laminate is not particularly limited. For example, Petition 870220063643, dated 07 / 19 / 2022, p. 32 / 108 13 / 83 Handmade paper or high-quality paper can be used. From the point of view of obtaining sufficient strength when used as a container, the basic weight of the paper substrate is preferably 150 to 450 g / m2, and more preferably 250 to 400 g / m2. Furthermore, from the point of view of obtaining suitable foaming properties of a thermoplastic resin such as polyethylene, the water content of the paper substrate is preferably 4 to 10% by mass, and more preferably 5 to 8% by mass. (Thermoplastic resin layer, foamed layer forming layer)

[00038] In one embodiment, the thermoplastic resin layer (A) and the foamed thermoplastic resin layer-forming layer (B0) (hereinafter also referred to as the foamed layer-forming layer (B0)) can each be a film formed from a resin material that is conventionally well known as a container material. For example, it is possible to use a film (thermoplastic resin film) formed from at least one type of thermoplastic resin selected from the group consisting of stretched and unstretched polyolefins polyester, nylon, cellophane and vinilon, wherein polyethylene and polypropylene are examples of stretched and unstretched polyolefins.

[00039] In one embodiment, a polyethylene film can be used appropriately due to its excellent suitability for lamination and foaming properties.

[00040] Foamed paper material can be constructed by laminating thermoplastic resin films with different melting points onto a paper substrate. Here, the materials Petition 870220063643, dated 07 / 19 / 2022, page 33 / 108 14 / 83 are selected so that the melting point (Mp) of the thermoplastic resin film supplied on one side of the paper substrate as the foamed layer forming layer (Bo) is lower than that of the thermoplastic resin film supplied on the other side of the paper substrate as the thermoplastic resin layer (A). In the foamed paper material, moisture in the paper substrate evaporates during heat treatment, and the evaporated moisture is pushed to the side of the foamed layer forming layer (Bo) (low Mp resin film) which softens. This pushing causes the low Mp resin film to expand (foam) outward, and a foamed layer (B) is formed. The foamed layer (B) thus formed acts as a thermal insulation layer in the container. Meanwhile, for the thermoplastic resin layer (A) (high Mp resin film), a material is selected that does not melt or soften when the low Mp resin film foams due to heat treatment. [ooo41]From the point of view of producing a foamed paper container using a foamed paper laminate, the foamed paper material may have a structure in which, for example, a high Mp polyethylene film (thermoplastic resin layer (A)) with a melting point of approximately 125°C to 140°C is laminated onto one surface of the paper substrate (inner side of the container), and a low Mp polyethylene film (foamed layer forming layer (Bo)) with a melting point of approximately 105°C to 120°C is laminated onto the other surface of the paper substrate (outer side of the container). Due to heating, such as during the production of the foamed paper container, the low Mp polyethylene film foams and Petition 870220063643, dated 07 / 19 / 2022, page 34 / 108 15 / 83 forms a foamed layer. Meanwhile, the high Mp polyethylene film preferably functions as a coating layer. In other words, the coating layer can suppress moisture in the paper substrate evaporating to the outside during the foaming of the low Mp polyethylene film, allowing the moisture in the paper substrate to efficiently contribute to foaming.

[00042] In one embodiment, among the polyethylene resins, the foam-forming layer material (B0) preferably includes a low-density polyethylene resin (density 910 to 925 kg / m3, melting point 105 to 120°C). The density of the low-density polyethylene resin is more preferably 910 to 922 kg / m3, and even more preferably 910 to 918 kg / m3. When a medium-density polyethylene resin (density 925 to 940 kg / m3, melting point 115 to 130°C) or a high-density polyethylene resin (density 940 to 970 kg / m3, melting point 125 to 140°C) is used as the foam-forming layer material (B0), the melting point is high and it tends to be difficult to obtain sufficient foaming properties.Furthermore, from the point of view of obtaining a uniform foamed layer, the melt flow rate (hereinafter referred to as MFR) of the polyethylene resin is preferably 8 to 28 g / 10 min, and more preferably 10 to 20 g / 10 min.

[00043] The thickness of the foamed layer-forming layer film (B0) is not particularly limited, but in one embodiment it is preferably 40 μm or more, and more preferably 60 μm or more. Insulation properties Petition 870220063643, dated 07 / 19 / 2022, p. 35 / 108 16 / 83 sufficient thermal properties can be obtained after heat treatment by adjusting the film thickness to 40 μm or more.

[00044] However, from the point of view of resource conservation, it is preferable to use the minimum amount of resin possible. Furthermore, also from the point of view of thermal insulation properties, it is not necessary for the foamed layer (B0) to be so thick as to result in excessive quality. Therefore, as the thickness of the foamed layer (Bo) film, 150 μm or less is preferred, 100 μm or less is more preferred, and 80 μm or less is highly preferred. (Printed layer)

[00045] In the foamed paper laminate of the above embodiment, the printed layer is a coating film obtained by applying a water-based ink composition to the surface of the foamed paper forming layer (Bo) of the foamed paper material. The main component of the coating film that constitutes the printed layer is a binder resin in the water-based ink composition, and the binder resin preferably contains at least one polyurethane resin.

[00046] By including at least one polyurethane resin as a binder resin, the printed layer can easily achieve excellent adaptability to foaming without hindering foaming when the foamed layer (Bo) foams due to heating to form the foamed layer (B). Furthermore, the foaming properties of the foamed layer (Bo) can be adequately suppressed, and the aforementioned number of foam cells per unit surface area of ​​the layer can be achieved. Petition 870220063643, dated 07 / 19 / 2022, page 36 / 108 17 / 83 foamed (B) can be easily obtained. It is therefore possible to obtain an excellent external foam appearance due to the use of a polyurethane resin, and also to easily obtain excellent abrasion resistance and thermal resistance of the printed layer.

[00047] In one embodiment, the thickness of the printed layer (the coating film after drying) is preferably from 0.5 to 5.0 μm from the point of view of the printed layer's ability to suppress foaming and abrasion resistance. The thickness of the printed layer can be more preferably from 0.5 to 4.0 μm, and even more preferably from 0.5 to 3.5 μm.

[00048] From the point of view of the ethanol resistance of the printed layer, the residual percentage of the printed layer after immersion for 30 minutes in ethanol at 25°C is preferably 50% by mass or more. If the residual percentage of the printed layer is 50% by mass or more, defects such as blurred printing can be suppressed and the printed layer can be satisfactorily maintained even when ethanol is used for disinfection and cleaning in a production process or similar for a food product container. Considering applications with a food product container, the residual percentage of the printed layer after immersion for 30 minutes in ethanol at 25°C is more preferably 60% by mass or more, and even more preferably 70% by mass or more.

[00049] The residual percentage of the printed layer described in this document does not require strict adjustment of the ethanol immersion conditions. In other words, conditions such as temperature and immersion time can be slightly adjusted. Petition 870220063643, dated 07 / 19 / 2022, page 37 / 108 18 / 83 modified. For example, immersion for 30 minutes means that it is sufficient for the printed layer to be immersed in ethanol for approximately 30 minutes. Therefore, for example, the immersion time can be extended from 5 to 10 minutes depending on the operations before and after immersion, post-treatment, and so on. For example, an agitation process can be provided as an operation before and after immersion. Agitation is preferably carried out at 50 to 150 rpm.

[00050] Generally, when compounding an aqueous ink composition, it is preferable to increase the hydrophilicity of the binder resin from the point of view of printability. However, if the hydrophilicity of the binder resin is increased, the ethanol resistance of the printed layer is likely to decrease. In response, by adjusting the structure and physical properties of the polyurethane resin used as a binder resin, it is possible to obtain the desired ethanol resistance, in addition to desired properties such as foam adaptability, foam suppression capacity, abrasion resistance, and thermal resistance, as described above. Specific embodiments of an aqueous ink composition containing a polyurethane resin as a binder resin are described below. <2> Water-based paint composition

[00051] An embodiment refers to a water-based ink composition that can be suitably used to form the printed layer of the foamed paper laminate of the embodiment above. The water-based ink composition contains a binder resin and water, and may also contain a colorant, such as a pigment. In addition to the above components, the water-based ink composition Petition 870220063643, dated 07 / 19 / 2022, p. 38 / 108 19 / 83 may still contain various additives as needed. The composition of the aqueous paint composition is described below. (Binder resin)

[00052] During the thermal processing to form the foam layer (B), it is preferable that the printed layer does not inhibit the foam formation of the foam-forming layer (B0) and has excellent foam formation adaptability. However, it is preferable that the foam formation of the foam-forming layer (B0) can be adequately controlled by the printed layer to suppress defects in the external appearance of the foam, such as cracks and bubbles on the printed surface. In response, since the binder resin is the main component of the printed layer (coating film), by selecting an appropriate binder resin, the foam adaptability and foam suppression capacity of the printed layer can be satisfactorily adjusted.

[00053] In one embodiment, the binder resin in the aqueous ink composition that forms the printed layer preferably has an elongation percentage of 50 to 4,000% from the point of view of adaptability to foam formation. However, even if the elongation percentage of the binder resin is 50 to 4,000%, if the tension is too small, the printed layer adapts to foam formation but is not able to adequately control foam formation, and cracking and bubbles are likely to occur, causing a decline in the external appearance of the foam. Therefore, from both the point of view of foam adaptability and the external foam appearance of the printed surface, it is preferable that the binder resin have a percentage Petition 870220063643, dated 07 / 19 / 2022, page 39 / 108 20 / 83 elongation of 50 to 4,000% and a strain of 0.1 MPa or higher.

[00054] Note that the term percentage of elongation described in this document means a value obtained by performing a measurement on a sample with dimensions of 0.3 mm thickness and 15 mm width, using a small tensile tester manufactured by Intesco Co., Ltd. at a tensile speed of 100 mm / min and an ambient temperature of 25°C.

[00055] In one embodiment, the binder resin has a tensile strength that is preferably 0.1 mPa or more, more preferably 1 mPa or more, and even more preferably 5 mPa or more, at an elongation percentage of 50 to 4,000%. Meanwhile, the tensile strength is preferably 50 mPa or less, more preferably 40 mPa or less, and even more preferably 30 mPa or less, at an elongation percentage of 50 to 4,000%. It is sufficient that the tensile strength of the binder resin is from 0.1 mPa to 50 mPa at an elongation percentage of 50 to 4,000%.

[00056] When the binder resin has an elongation and tension percentage in the above ranges, it is easy to obtain favorable results for the external appearance of the foam, as well as the foam's adaptability. Furthermore, a binder resin with an elongation and tension percentage in the above ranges is also preferred from the point of view of increasing ethanol resistance, since it is easy to obtain the desired residual percentage of the printed layer.

[00057] In one embodiment, the binder resin preferably has a glass transition temperature (Tg) of -100°C to 0°C. The Tg of the binder resin can be in a way Petition 870220063643, dated 07 / 19 / 2022, page 40 / 108 21 / 83 is most preferably -10°C or lower, and even more preferably -25°C or lower. When the Tg of the binder resin is within the above ranges, excellent adaptability to foam formation can be obtained during the heat treatment of the foamed paper material, and a decline in thermal insulation properties can be suppressed. Furthermore, it is possible to suppress defects in the external appearance of foam, such as cracks and bubbles on the printed surface. A Tg of -100°C or higher is sufficient; -90°C or higher is preferable, and -80°C or higher is most preferable. A binder resin with a Tg in the above ranges is also preferred from the point of view of ethanol resistance, since it is easy to obtain the desired residual percentage of the printed layer.

[00058] As mentioned above, it is preferable that the binder resin contain at least a polyurethane resin from the point of view of adaptability to foam formation and so on of the printed layer during foam formation. When using a polyurethane resin, it is easy to form an aqueous ink composition capable of forming an excellent printed layer in terms of various types of resistance, such as light resistance, thermal resistance, abrasion resistance and blockage resistance, and which also has excellent adhesion to the low Mp resin film (foamed layer formation layer (B0)) serving as a substrate during printing. Furthermore, using a polyurethane resin as a binder resin, even when the aqueous ink composition is stored for a long period of time in an environment where heat or light is applied, favorable results can also be obtained in terms of various characteristics, Petition 870220063643, dated 07 / 19 / 2022, page 41 / 108 22 / 83 provides abrasion resistance and blockage resistance to the printed layer, and adhesion to the low Mp resin film that serves as the substrate.

[00059] A conventionally well-known resin other than a polyurethane resin can be used as a binder resin. By using various resins with elongation, tensile strength, and Tg percentages in the above ranges, excellent printing characteristics can be easily obtained. Control of the elongation and tensile strength percentage of the binder resin can be achieved by combining various resins, controlling the molecular weight at the time of resin synthesis, altering the monomer Tg, adjusting the crosslinking density, and so on. From this point of view, an acrylic resin, styrene-acrylic copolymer resin, styrene-maleic acid copolymer resin, and the like are examples of resins that can be used as a binder resin other than a polyurethane resin.

[00060] In one embodiment, the polyurethane resin content is preferably 50% by mass or more, more preferably 70% by mass or more, and even more preferably 85% by mass or more, relative to the total mass of the resin component in the binder resin. In one embodiment, the binder resin may be formed solely from a polyurethane resin.

[00061] The term polyurethane resin used in this document means polyurethane resins in a broad sense, including common polyurethane resins conventionally used in the technical field in question and modified polyurethane resins, such as polyurethane-urea resins. Furthermore, the polyurethane resin used in this Petition 870220063643, dated 07 / 19 / 2022, p. 42 / 108 23 / 83 document is not particularly limited by its production method and may be various polyurethane resins obtained by applying publicly known or well-known methods related to polyurethane resins. Polyurethane resins that can be suitable for use as a binder resin are described more specifically below. (Polyurethane resin)

[00062] Polyurethane resin is not particularly limited, but an example of a preferred embodiment thereof is a polyurethane resin obtained by the reaction of at least one polyol and a polyisocyanate. In addition, another possible embodiment is a polyurethane-urea resin obtained by chain extension of a polyurethane resin prepolymer with an amine compound.

[00063] In one embodiment, the polyurethane resin used as a binder resin is preferably an aqueous polyurethane resin (also referred to as a polyurethane resin that has become aqueous) from the point of view of preparing an aqueous paint composition. The term aqueous polyurethane resin described in this document means that the polyurethane resin is soluble or readily dispersible in water or a water-soluble solvent. In other words, in one embodiment, it is preferable that the polyurethane resin has an acid value (acid functional group) and can assume a water-soluble or emulsion-soluble form by neutralization or modification of the acid functional group. The acid functional group can be a carboxyl group or a sulfonic acid group, and a carboxyl group is preferred. The polyurethane resin used as a binder resin is not Petition 870220063643, dated 07 / 19 / 2022, p. 43 / 108 24 / 83 is particularly limited, but is preferably soluble in water.

[00064] However, generally, when a water-based polyurethane resin is used to compose a water-based ink composition, it tends to be difficult to obtain sufficient ethanol resistance in the printed layer considering its use in a food product container. Therefore, from the point of view of imparting the desired ethanol resistance to the printed layer, the polyurethane resin used as a binder resin preferably has a structure or physical properties such that dissolution in ethanol is difficult. The ethanol resistance of a printed surface can be easily improved by the methods described below; however, the method used is not particularly limited to it.

[00065] For example, one method is to select a polyol that has a structure that is difficult to dissolve in ethanol, such as a polyol that is the main constituent component of polyurethane resin. In this method, it is preferable that at least one of a polycarbonate diol and one polyester polyol be used as the polyol.

[00066] Another method is to increase the weight-average molecular weight of the polyurethane resin. In one embodiment, when the weight-average molecular weight of the polyurethane resin is greater than 20,000, ethanol resistance can be easily increased. However, the weight-average molecular weight of the polyurethane resin is not particularly limiting. Even when the weight-average molecular weight of the polyurethane resin is 20,000 or less, excellent ethanol resistance can be easily obtained using a Petition 870220063643, dated 07 / 19 / 2022, page 44 / 108 25 / 83 cure agent in combination, for example.

[00067] Another method is to increase the glass transition temperature (Tg) of the polyurethane resin. The preferred range of the polyurethane resin's Tg can be from -100°C to 0°C, as previously described as a characteristic of the binder resin. In one embodiment, from the point of view of ethanol resistance, the Tg of the polyurethane resin is preferably -80°C or higher, more preferably -70°C or higher, and most preferably -60°C or higher. However, the Tg of the polyurethane resin is preferably -10°C or lower, and most preferably -20°C or lower.

[00068] Another method is to adjust the strength (percentage of elongation and tensile strength) of the polyurethane resin. Associated with this, methods for adjusting the concentration of urethane binder or the concentration of urea binder in the polyurethane resin are also feasible. Note that the preferred range of percentage of elongation and tensile strength of the polyurethane resin may be a tensile strength of 0.1 mPa or higher at a percentage of elongation of 50 to 4,000% as previously described as a characteristic of the binder resin. In one embodiment, from the point of view of ethanol resistance, the percentage of elongation of the polyurethane resin is preferably 100 to 2,500%, more preferably 300 to 1,500%, and even more preferably 300 to 1,200%. The voltage is preferably 1 to 40 mPa, more preferably 3 to 30 mPa, and even more preferably 5 to 25 mPa.

[00069] Using a composite polyurethane resin by applying any of the above methods or a combination thereof. Petition 870220063643, dated 07 / 19 / 2022, page 45 / 108 26 / 83 of a plurality of methods as a binder resin, it is possible to easily form a printed layer with a residual percentage after immersion for 30 minutes in ethanol at 25°C of 50% by mass or more.

[00070] The raw materials and production method for polyurethane resin are described below. (Polyol)

[00071] Several polyols can be used to produce a polyurethane resin. For example, the various polyols listed below can be used appropriately. The various polyols listed below can be used alone or two or more types can be used in combination. (1) Polyether polyols, such as polymers or copolymers of ethylene oxide, propylene oxide, tetrahydrofuran or the like; (2) Polyester polyols obtained by condensation dehydration of: Low molecular weight saturated and unsaturated glycols, such as ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, 2-methyl-1,3-propanediol, neopentyl glycol, pentanediol, 3-methyl-1,5-pentanediol, hexanediol, octanediol, nonanediol, methylnonanediol, diethylene glycol, triethylene glycol, and dipropylene glycol; Alkylglycidyl ethers, such as n-butyl glycidyl ether and 2-ethylhexyl glycidyl ether; monocarboxylic acid glycidyl esters, such as versatile acid glycidyl ester; and dibasic acids, such as adipic acid, phthalic acid, isophthalic acid, terephthalic acid, maleic acid, Petition 870220063643, dated 07 / 19 / 2022, page 46 / 108 27 / 83 fumaric acid, succinic acid, oxalic acid, malonic acid, glutaric acid, pimelic acid, azelaic acid, sebacic acid and dimeric acid or anhydrides thereof; (3) Other polycarbonate diols, polybutadiene glycols and glycols obtained by adding ethylene oxide or propylene oxide to bisphenol A; and (4) Dimer diols.

[00072] In one embodiment, the polyurethane resin is preferably made from at least one type of polyol selected from a polyether polyol, polyester polyol, and polycarbonate diol, and preferably has a structural unit derived from these raw materials. It is more preferable to use a polyether polyol and / or a polyester polyol as the polyol. That is, in one embodiment, the polyurethane resin can be a polyether-based polyurethane resin, a polyester-based polyurethane resin, or a polyester / polyester polyurethane resin.

[00073] Polyether polyols preferably include at least one type selected from polyethylene glycol, polypropylene glycol and polytetramethylene glycol and, more preferably, include polyethylene glycol.

[00074] Polyester polyols preferably include a polyester polyol that is a condensation product of a low molecular weight diol and a dibasic acid. The low molecular weight diol is preferably a branched diol. The term branched diol means that at least one hydrogen atom of an alkylene group of an alkylene glycol is replaced by a branched diol. Petition 870220063643, dated 07 / 19 / 2022, page 47 / 108 28 / 83 different from a hydrogen atom. The substituent is preferably an alkyl group of 1 to 10 carbon atoms.

[00075] In one embodiment, in a case where a polyester polyol listed in (2) above is used to compose a polyester-based polyurethane resin, up to 5 mol% of the mixture amount of the polyol may be replaced by several other polyols. Examples of several other polyols include glycerin, trimethylolpropane, trimethylolethane, 1,2,6-hexanetriol, 1,2,4-butanetriol, and pentaerythritol.

[00076] The structure and number-average molecular weight of the polyol are appropriately determined taking into account the characteristics of the polyurethane resin obtained as a reaction product, such as ethanol resistance, dryability, elongation percentage, and tensile strength. The number-average molecular weight of a polyol is not particularly limited, but is generally preferably in the range of 500 to 10,000, and more preferably in the range of 500 to 6,000. (Polyisocyanate)

[00077] A polyisocyanate that can be used in the production of a polyurethane resin is preferably a diisocyanate compound. Specific examples include aromatic diisocyanates, aliphatic diisocyanates, and alicyclic diisocyanates. The polyisocyanate may be a compound with an isocyanurate ring structure formed by trimerization of several diisocyanates.

[00078] Examples of aromatic diisocyanates include 1,5-naphthylene diisocyanate, 4,4'diphenylmethane diisocyanate (MDI), 4,4'diphenyldimethylmethane diisocyanate, 4,4'-dibenzyl isocyanate, di Petition 870220063643, dated 07 / 19 / 2022, page 48 / 108 29 / 83 dialkyldiphenylmethane isocyanate, tetraalkyldiphenylmethane diisocyanate, 1,3-phenylene diisocyanate, 1,4phenylene diisocyanate and tolylene diisocyanate.

[00079] Examples of aliphatic diisocyanates include butane-1,4-diisocyanate, hexamethylene diisocyanate, isopropylene diisocyanate, methylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate and lysine diisocyanate.

[00080] Examples of alicyclic diisocyanates include cyclohexane-1,4-diisocyanate, xylylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, 1,3-bis(isocyanatomethyl)cyclohexane, methylcyclohexane diisocyanate, norbornane diisocyanate, m-tetramethylxylylene diisocyanate, hydrogenated 4,4-diphenylmethane diisocyanate, and a dimer diisocyanate obtained by replacing a carboxyl group of a dimeric acid with an isocyanate group.

[00081] Among the polyisocyanates listed above, at least one type is preferred from the group consisting of tolylene diisocyanate, isophorone diisocyanate, xylylene diisocyanate, bis(isocyanatomethyl)cyclohexane, hexamethylene diisocyanate, and hexamethylene diisocyanate trimer. One of these polyisocyanates may be used alone or a mixture of two or more types may be used. (Dihydroxy acid)

[00082] When a dihydroxy acid is used in addition to a polyol and a polyisocyanate in the production of a polyurethane resin, an acidic functional group (carboxyl group) derived from the dihydroxy acid is introduced and a resin of Petition 870220063643, dated 07 / 19 / 2022, page 49 / 108 30 / 83 polyurethane with an acid value can be obtained. A polyurethane resin with an acid value can be easily made aqueous and can therefore be used appropriately as an aqueous polyurethane resin to compose an aqueous paint composition.

[00083] It is sufficient that the dihydroxy acid be a compound with two hydroxyl groups and an acid group in the molecule. A well-known diol compound containing a carboxyl group may be used appropriately. For example, a dimethylolalkanoic acid, such as 2,2-dimethylolpropionic acid, 2,2-dimethylolbutyric acid, and 2,2-dimethylolvaleric acid may be used appropriately. These may be used alone or two or more types may be used in combination.

[00084] In one embodiment, when producing a polyurethane-urea resin as a polyurethane resin, it is desirable that the molar equivalent ratio of isocyanate groups / hydroxyl groups be adjusted to be in the range of 1.2 / 1 to 3 / 1. In another embodiment, when producing a polyurethane resin that does not contain a urea linker, it is desirable that the molar equivalent ratio of isocyanate groups / hydroxyl groups be adjusted to be in the range of 0.5 / 1 to 0.98 / 1. When the raw materials are mixed in the above molar equivalent ratio ranges, it is easy to control the percentage of elongation and tensile strength of the polyurethane resin, and also its resistance to ethanol. The polyurethane reaction in the production of a polyurethane resin is generally carried out at a reaction temperature in the range of 80°C to 200°C, and preferably in the range of 90°C to 150°C.

[00085] The polyurethane reaction can be carried out in a solvent or it can be carried out in a solvent-free atmosphere. Petition 870220063643, dated 07 / 19 / 2022, pp. 50 / 108 31 / 83 solvent. When a solvent is used, one may be appropriately selected from those listed below from the point of view of controlling the reaction temperature, viscosity, and secondary reactions. Furthermore, when carrying out the polyurethane reaction in a solvent-free atmosphere, it is desirable to carry out the reaction after decreasing the viscosity by increasing the temperature (heating) as long as sufficient agitation can be achieved in order to obtain a polyurethane resin. It is desirable that the reaction time of the polyurethane reaction be adjusted to 10 minutes to 5 hours. The reaction completion point can be determined by methods such as viscosity measurement, confirmation of the NCO peak by IR measurement, and % NCO measurement by titration.

[00086] In one embodiment, a polyurethane-urea resin that can be suitably utilized is a resin obtained by reacting a polyol and an organic diisocyanate listed above to synthesize a polyurethane resin prepolymer with isocyanate groups at the ends and then introducing a urea linkage into the polyurethane resin prepolymer using an amine compound as a chain extending agent and a reaction termination agent. Among polyurethane resins, when the above polyurethane-urea resin is used, several characteristics of the coating film (printed surface) obtained using the aqueous ink composition can be improved. (Chain extension agent)

[00087] Examples of chain-extending agents that can be used to introduce a urea linkage include several publicly known polyamines. A polyamine means a compound with a plurality of amino groups in the molecule. Petition 870220063643, dated 07 / 19 / 2022, page 51 / 108 32 / 83

[00088] Specific examples of polyamines include ethylenediamine, propylenediamine, hexamethylenediamine, triethylenetetramine, diethylenetriamine, isophorone diamine, and dicyclohexylmethane-4,4'-diamine. Other specific examples include: diamines with a hydroxyl group in the molecule, such as 2-hydroxyethyl ethylenediamine, 2-hydroxyethyl propylenediamine, di-2-hydroxyethyl ethylenediamine, di-2-hydroxyethyl propylenediamine, 2-hydroxypropyl ethylenediamine, and di-2-hydroxypropyl ethylenediamine; and dimeric diamines obtained by replacing a carboxyl group of a dimeric acid with an amino group. (Reaction termination agent)

[00089] A reaction-terminating agent may also be used in combination with a polyamine. Examples of reaction-terminating agents include: dialkylamines, such as dibutylamine; amines with a hydroxyl group, such as monoethanolamine, diethanolamine, 2-amino-2-methyl-1-propanol, tri(hydroxymethyl)aminomethane, 2-amino-2-ethyl-1,3-propanediol, N-di-2-hydroxyethylethylenediamine, N-di-2-hydroxyethylpropylenediamine and N-di-2-hydroxypropylethylenediamine; and monoamine-type amino acids, such as glycine, alanine, glutamic acid, taurine, aspartic acid, aminobutyric acid, valine, aminocaproic acid, aminobenzoic acid, aminoisophthalic acid and sulfamic acid.

[00090] The production method for introducing a urea linker into a polyurethane resin prepolymer is not particularly limited. For example, when the number of free isocyanate groups present at both ends of the prepolymer is defined as 1, it is preferable to adjust the Petition 870220063643, dated 07 / 19 / 2022, page 52 / 108 33 / 83 The total number of amino groups in the chain-extending agent and reaction-terminating agent being used is in the range of 0.5 to 1.3.

[00091] The solvent used in the production of polyurethane resin and in the production of polyurethane-urea resin may be a well-known compound that can generally be used as a solvent for inks that form a printed layer. Examples include alcohol-based solvents such as methanol, ethanol, isopropanol, n-propanol, and n-butanol; ketone-based solvents such as acetone, methyl ethyl ketone, and methyl isobutyl ketone; ester-based solvents such as ethyl acetate, propyl acetate, and butyl acetate; and non-aromatic hydrocarbon-based solvents such as methylcyclohexane and ethylcyclohexane. These solvents may be used alone, or two or more types may be used in combination.

[00092] When a ketone-based solvent mentioned above is used during production, ketimine is produced between the ketone and the amine used as a chain-extending agent, and this product inhibits the smooth progression of the reaction. Therefore, to suppress ketimine generation and allow for smooth reaction progression, it is desirable to use a small amount of water in combination. When an organic solvent is used in a synthesis reaction, it is preferable to provide a process for removing and replacing the organic solvent with water by distillation under reduced pressure to prepare an aqueous solution of a polyurethane resin.

[00093] In one embodiment, the polyurethane resin is preferably a polyurethane resin with an acid value, since it can be easily made aqueous by Petition 870220063643, dated 07 / 19 / 2022, page 53 / 108 34 / 83 Neutralization. In one embodiment, the polyurethane resin preferably has an acid value of 1 to 100 mg KOH / g. The acidity index is more preferably 10 to 70 mg KOH / g, and even more preferably 20 to 60 mg KOH / g. The hydroxyl index of the polyurethane resin is not particularly limited, but is preferably 1 to 20 mg KOH / g. In this document, the acid value and the hydroxyl value are measured according to methods described in JISK0070 (1992). (Neutralizing agent)

[00094] Several neutralizing agents can be used to make a polyurethane resin with an acid value aqueous by neutralization. For example, a basic compound can be used to neutralize a carboxyl group in a polyurethane resin.

[00095] Specific examples of basic compounds that can be used as neutralizing agents include sodium hydroxide, potassium hydroxide, ammonia, methylamine, ethylamine, propylamine, butylamine, hexylamine, octylamine, ethanolamine, propanolamine, diethanolamine, N-methyldiethanolamine, dimethylamine, diethylamine, triethylamine, N,N-dimethylethanolamine, 2-dimethylamino-2-methyl-1-propanol, 2-amino-2-methyl-1-propanol, and morpholine. One type of this can be used alone, or two or more types can be used in combination. Ammonia is preferred in terms of water resistance of the printed item, residual odor, and so on.

[00096] The method for producing aqueous polyurethane resin can be a conventionally known or well-known method and is not particularly limited. By Petition 870220063643, dated 07 / 19 / 2022, page 54 / 108 35 / 83 For example, reference may be made to the methods for producing an aqueous polyurethane resin described in Japanese Unexamined Patent Application Publications Nos. 2013-234214, 2013-249401, 2015-67818 and 2018-184512.

[00097] In one embodiment, when an aqueous polyurethane resin is used as the binder resin, its weight-average molecular weight can be in the range of 5,000 to 100,000, more preferably 10,000 to 90,000, and even more preferably 20,000 to 80,000. When the weight-average molecular weight of the polyurethane resin is within the above ranges, it is easy to obtain the desired characteristics, such as percentage elongation and tensile strength. Furthermore, in one embodiment, from the point of view of increasing ethanol resistance, the weight-average molecular weight of the polyurethane resin is preferably 21,000 to 80,000, more preferably 25,000 to 75,000, and particularly preferably 30,000 to 70,000.

[00098] The polyurethane resin used as a binder resin is not particularly limited, but in a preferred embodiment it may be an aqueous solution of polyurethane resin obtained as follows. (1) First, a poly(3-methyl-1,5-pentane adipato)diol, polyethylene glycol and dimethylolbutanoic acid are mixed and stirred, and then isophorone diisocyanate is added and reacted to form a terminal isocyanate prepolymer (I). Next, 2-aminoethylethanolamine and an organic solvent, such as isopropyl alcohol, are respectively added to the terminal isocyanate prepolymer (I) to form a solvent-type polyurethane resin solution. Petition 870220063643, dated 07 / 19 / 2022, page 55 / 108 36 / 83 (2) Next, ammonia water and ion exchange water are gradually added to the solvent-type polyurethane resin solution to neutralize it and form an aqueous polyurethane resin solution. In addition, the organic solvent in the aqueous polyurethane resin solution is removed by distillation under reduced pressure and then water is added to adjust the solids content to obtain an aqueous polyurethane resin solution (aqueous polyurethane resin solution).

[00099] In one embodiment, the urethane resins (A) to (G) described below in the examples can be suitably used as binder resins to compose an aqueous paint composition. Urethane resins (A) to (G) can be used individually, but it is more preferable to use two or more types in combination, as this facilitates the adjustment of various characteristics. For example, when urethane resin (A) and urethane resin (B) are used together, more suitable characteristics tend to be obtained. [000100]In one embodiment, the total binder resin content relative to the total mass of the aqueous ink composition (solid content) is preferably 30% by mass or less, and more preferably in the range of 5 to 25% by mass. When the amount of binder resin used is adjusted to be within the above ranges, it is easy to obtain an appropriate ink viscosity and the efficiency of the operation at the time of ink production and printing can be increased. (Curing agent) [000101]In one embodiment, the aqueous ink composition preferably also contains a curing agent for the Petition 870220063643, dated 07 / 19 / 2022, pp. 56 / 108 37 / 83 resin used as a binder resin. When the aqueous ink composition contains a curing agent, the printed layer is formed from a cured coating film; however, its reaction form is not particularly limited. That is, the printed layer may be a cured coating film formed from the resin in the binder resin and the curing agent. Alternatively, the printed layer may be a cured coating film formed from the curing agent itself. [000102] In one embodiment, when a polyurethane resin with an acid value is used as a binder resin, the aqueous paint composition preferably also contains a curing agent. In one embodiment, the polyurethane resin preferably has an acid value of 1 to 100 mg KOH / g. The acidity index is more preferably 10 to 70 mg KOH / g, and even more preferably 20 to 60 mg KOH / g. [000103] In one embodiment, when a polyurethane resin with an acid value of 1 to 100 mg KOH / g is used in combination with a curing agent, it is easy to form a printed layer with a residual percentage after immersion for 30 minutes in ethanol at 25°C of 50% or more. Therefore, excellent ethanol resistance can be easily perceived in the printed layer. Furthermore, according to an embodiment in which the aqueous ink composition contains a polyurethane resin with an acidity index of 1 to 100 mg KOH / g and a curing agent, in addition to ethanol resistance, favorable results can also be obtained for various characteristics such as abrasion resistance and the foamy external appearance of the printed surface. Petition 870220063643, dated 07 / 19 / 2022, page 57 / 108 38 / 83 [000104]As a curing agent for a polyurethane resin with an acid value, compounds that are well known in the technical field can be used. Among them, it is preferable to use at least one type of curing agent selected from the group consisting of epoxy-based curing agents, carbodiimide-based curing agents, and isocyanate-based curing agents. In one embodiment, it is more preferable to use at least one carbodiimide-based curing agent and one isocyanate-based curing agent. It is even more preferable to use at least one carbodiimide-based curing agent. [000105] In one embodiment, the aqueous ink composition for forming the printed layer preferably contains an aqueous polyurethane resin with an acid value of 1 to 100 mg KOH / g and at least one carbodiimide-based curing agent and one isocyanate-based curing agent. A printed layer formed using this type of aqueous ink composition contains a cured product (cured coating film) formed from the aqueous polyurethane resin with an acid value of 1 to 100 mg KOH / g and at least one carbodiimide-based curing agent and one isocyanate-based curing agent. [000106] It is sufficient that the carbodiimide-based curing agent be a compound with one carbodiimide group in the molecule. Compounds with two or more carbodiimide groups in the molecule are preferred. Specific examples of carbodiimide-based curing agents include p-phenylene-bis(2,6-xylylcarbodiimide), tetramethylene-bis(t-butylcarbodiimide), and cyclohexane-1,4-bis(methylene-t-butylcarbodiimide). The carbodiimide-based curing agent may be a Petition 870220063643, dated 07 / 19 / 2022, pp. 58 / 108 39 / 83 is a polycarbodiimide compound, which is a polymer with a carbodiimide group. These can be used alone, or two or more types can be used in combination. [000107]In one embodiment, the compound used as a carbodiimide-based curing agent preferably has a chemical formula weight per 1 mol of carbodiimide groups (NCN equivalent) of 250 to 700 and more preferably 300 to 600. Commercially available products can also be used as the carbodiimide-based curing agent, for example, the CARBODILITE V02, V-02-L2, SV-02, V-04, V-10, SW-12G, E-02, E-03A, E-05 series, and so on manufactured by Nisshinbo Chemical Inc. One type of this can be used alone or two or more types can be used in combination. [000108] It is sufficient that the isocyanate-based curing agent be a compound with one isocyanate group in the molecule. Compounds with two or more isocyanate groups in the molecule are preferred. A compound used as an isocyanate-based curing agent is preferably made aqueous, i.e., it is dispersed in water or diluted with water. Such aqueous isocyanate-based curing agents can be obtained as commercially available products and include Aquanate 100, Aquanate 110, Aquanate 200 and Aquanate 210 (all trade names, manufactured by Nippon Polyurethane Industry Co., Ltd.); Bayhydur TPLS-2032, SubIsocyanate L801, Bayhydur VPLS-2319, Bayhydur 3100, VPLS2336 and VPLS-2150 / 1 (all trade names, manufactured by Sumika Bayer Urethane Co., Ltd.); Takenate WD-720, Takenate WD-725 and Takenate WD-220 (all trade names, manufactured by Mitsui Takeda Chemicals Co.); and RESAMINE D. Exclusion 870220063643, dated 07 / 19 / 2022, page 59 / 108 40 / 83 (trade name, manufactured by Dainichiseika Color & Chemicals Mfg. Co., Ltd.). One type of this can be used alone, or two or more types can be used in combination. [000109]In one embodiment, in a water-based ink composition to form a printed layer, the amount of curing agent mixture is, by mass ratio of binder resin to curing agent, preferably 100:1 to 100:100, more preferably 100:2 to 100:60, and even more preferably 100:3 to 100:30. [000110]It is preferable that the amount of curing agent mixture be adjusted according to the composition of the printed layer. More precisely, in one embodiment, the amount of curing agent mixture when the printed layer is formed as a single layer is, by the mass ratio of binder resin to curing agent, preferably 100:2 to 100:100, more preferably 100:2 to 100:60, and even more preferably 100:5 to 100:30. [000111]In one embodiment, the amount of curing agent mixture when the printed layer is formed as a plurality of layers is, by the mass ratio of binder resin to curing agent in each layer, preferably 100:1.5 to 100:100, more preferably 100:2 to 100:60, and even more preferably 100:3 to 100:30. [000112] By adjusting the amount of curing agent mixture to be within the above ranges, it is possible to easily form a printed layer with a residual percentage of 50% or more after immersion for 30 minutes in ethanol at 25°C. As a result, it is possible to easily obtain excellent foaming adaptability and excellent external foaming appearance, abrasion resistance, Petition 870220063643, dated 07 / 19 / 2022, pp. 60 / 108 41 / 83 thermal resistance and ethanol resistance of the printed surface. (Dye) [000113]The dye used in the aqueous composition of ink can be one of several inorganic and organic pigments commonly used in printing inks and coating materials. Examples of inorganic pigments include white pigments such as titanium oxide; colored pigments such as Bengara, Prussian blue, ultramarine blue, carbon black, and graphite; and extender pigments such as calcium carbonate, kaolin, clay, barium sulfate, aluminum hydroxide, and talc. Additionally, examples of organic pigments include colored pigments such as soluble azo pigments, insoluble azo pigments, azo chelate pigments, condensed azo pigments, copper phthalocyanine pigments, and condensed polycyclic pigments.The content of these pigments can be appropriately selected taking into account the desired color tone of the paint and similar products, but in general the content is preferably in the range of 0.5 to 50% by mass relative to the total mass of the aqueous paint composition. [000114] In one embodiment, when preparing a white water-based paint composition, the amount of a white pigment mixture is preferably set in the range of 20 to 50% by mass relative to the total mass of the water-based paint composition. From the point of view of concealment, pigment concentration and lightfastness, it is preferable to use titanium dioxide as the white pigment. Meanwhile, when preparing a colored water-based paint composition, colored organic pigments and colored inorganic pigments, such as Bengara, Petition 870220063643, dated 07 / 19 / 2022, pp. 61 / 108 42 / 83 Prussian blue, ultramarine blue, carbon black, and graphite can be suitablely selected and used. From the point of view of color development and lightfastness, an organic pigment is preferable. The amount of colored pigment mixture is preferably in the range of 10 to 30% by mass relative to the total mass of the aqueous paint composition. [000115]In aqueous ink compositions, an organic solvent may be used in addition to water as a solvent insofar as this does not interfere with the effect of the aqueous ink composition. When an organic solvent must be used, an alcohol-based organic solvent is preferred. Specific examples of organic solvents include ethanol, 1-propanol, 2-propanol, 1-butanol, 2-methyl-1-propanol, 2-butanol, t-butanol, and 2-methyl-2-propanol. When these organic solvents are used, they are preferred because it is possible to control the wettability relative to the substrate and thus of the aqueous ink composition. In one embodiment, the substrate may be a foamed paper material. The aqueous ink composition is applied to the top surface of the foamed layer-forming layer (B0) of the foamed paper material to form a printed layer. [000116] If the aqueous paint composition contains an organic solvent, the amount of the mixture is preferably 30% by mass or less, more preferably 20% by mass or less, and even more preferably 10% by mass or less, relative to the total mass of the aqueous paint composition. In one embodiment, the content of the organic solvent in the aqueous paint composition is Petition 870220063643, dated 07 / 19 / 2022, pp. 62 / 108 43 / 83 is more preferably 5% by mass or less, and the aqueous paint composition need not contain an organic solvent. <Outros aditivos> [000117]The aqueous paint composition may additionally contain various additives as needed. Suitable examples of additives include antiblocking agents, various waxes, thickening agents, rheology modifiers, antifoaming agents, leveling agents, preservatives, surface tension modifiers, adhesion aids, and pH adjusters. (Adhesion aid) [000118]The aqueous ink composition may additionally contain an adhesion aid to improve adhesion between the printed layer and the substrate. It is preferable to use at least one hydrazine-based compound and one epoxy compound as an adhesion aid. [000119] Adipic acid dihydrazide, sebacic acid dihydrazide, isophthalic acid dihydrazide, and other dihydrazide compounds are preferred as a hydrazine-based compound. [000120]An epoxy compound means a compound containing an epoxy group. Examples include alicyclic epoxies such as ADEKA RESIN EP-4000, EP-4005 and 7001 manufactured by ADEKA. Corporation. [000121]These adhesion aids are preferably used at 0.1 to 5% by mass, and more preferably at 0.1 to 3% by mass, relative to the total mass of the aqueous paint composition. [000122]In one embodiment, when a white paint composition is compounded as a water-based paint composition, Petition 870220063643, dated 07 / 19 / 2022, pp. 63 / 108 44 / 83 A preferred composition is 10 to 50% by mass of white inorganic pigment, 5 to 35% by mass of polyurethane resin (solids content), and 5 to 30% by mass of water, relative to the total mass of white paint. A more preferred composition for the white paint composition is 20 to 50% by mass of white inorganic pigment, 5 to 30% by mass of polyurethane resin (solids content), and 5 to 25% by mass of water. As another embodiment, in addition to the above-mentioned composition for the white paint composition, 0.5 to 15% by mass of a curing agent may also be included. The curing agent preferably contains at least one carbodiimide-based curing agent and one isocyanate-based curing agent. [000123] In one embodiment, when a colored ink composition, such as magenta, yellow, and cyan, is composed as a water-based ink composition, a preferred composition is 10 to 25% by mass of organic pigment, 5 to 35% by mass of polyurethane resin (solids content), and 5 to 30% by mass of water, relative to the total mass of colored ink. A more preferred composition for colored ink is 10 to 20% by mass of organic pigment, 5 to 30% by mass of polyurethane resin (solids content), and 5 to 25% by mass of water. As another embodiment, in addition to the above-mentioned composition for colored ink, 0.5 to 15% by mass of a curing agent may be additionally included. The curing agent preferably contains at least one carbodiimide-based curing agent and one isocyanate-based curing agent. [000124]The aqueous ink composition that forms a printed layer can be produced by mixing the various components mentioned above using a well-known technique. More Petition 870220063643, dated 07 / 19 / 2022, pp. 64 / 108 45 / 83 specifically, an example method is one in which, first, a binder resin, water and, as needed, a pigment, a pigment dispersant, a surfactant and the like are stirred and mixed and then the mixture is kneaded using various kneading machines such as a ball mill, a sand mill, a crusher, a roller mill and a pearl mill, and other remaining materials are added and mixed. <3> Method for producing foamed paper laminate [000125] An embodiment refers to a method for producing a foamed laminate. In other words, an embodiment refers to a method for producing a foamed paper laminate that has: foamed paper with a thermoplastic resin layer (A), a paper substrate and a foamed layer (B) in this order; and a printed layer formed on the surface of the foamed layer (B) of the foamed paper, in which the number of foamed cells per unit surface area of ​​the foamed layer (B) is 1,000 cells / 1 cm2 or more, and the residual percentage of the printed layer after immersion for 30 minutes in ethanol at 25°C is 50% by mass or more. This production method includes the following processes (i) to (iv), namely: (i) prepare a foamed paper material having, in the following order, a thermoplastic resin layer (A), a paper substrate and a foamed layer-forming layer (B0), which has a lower melting point than the thermoplastic resin layer (A) and foams by heating; (ii) prepare an aqueous paint composition containing a binder resin containing a polyurethane resin and Petition 870220063643, dated 07 / 19 / 2022, pp. 65 / 108 46 / 83 water; (iii) apply the aqueous ink composition to the surface of the foamed layer forming layer (Bo) of the foam paper material to form a printed layer; and (iv) heat the foam paper material with the printed layer to thereby cause the foamed layer forming layer (B0) of the foam paper material to foam to form the foamed layer (B). [000126]In the production method, the processes related to (i) preparing the foamed paper material, (ii) preparing the aqueous ink composition, (iii) forming the printed layer, and (iv) forming the foamed layer (B) by heating, can each be carried out according to methods that are well known in the technical field. Each process is described below. (Process (i): Preparation of foamed paper material) [000127](i) The preparation of the foamed paper material can be carried out according to an extrusion lamination method, for example. The constituent materials of the paper substrate, thermoplastic resin layer (A) and foamed layer-forming layer (B0), which constitute the foamed paper material, are as described above. As the extrusion lamination method, a well-known method, such as the simple lamination method, the tandem lamination method, the sandwich lamination method and the co-extrusion lamination method, can be appropriately selected. In one embodiment, polyethylene resins with different melting points can be suitablely used as constituent materials of the thermoplastic resin layer (A) and the foamed layer-forming layer. Petition 870220063643, dated 07 / 19 / 2022, pp. 66 / 108 47 / 83 foamed (Bo). [000128]The foamed layer (Bo) is composed of a polyethylene resin (low Mp polyethylene resin (Mp: melting point)) having a lower Mp than the Mp of a polyethylene resin that constitutes the thermoplastic resin layer (A). The foamed paper material can be produced by extruding the low Mp polyethylene resin in film form onto one side of the paper substrate and extruding the high Mp polyethylene resin in film form onto the other side of the paper substrate, using a T-die extruder. [000129]The temperature of the polyethylene resin during lamination (temperature directly below the matrix T) is preferably 300 to 350°C, and more preferably 320 to 340°C. Within this temperature range, sufficient lamination strength can be achieved between each layer of polyethylene resin (A, B0) and the paper substrate. The surface temperature of the cooling rollers through which the foamed paper material passes after lamination is preferably controlled to be in the range of 10 to 50°C. [000130] In one embodiment, the lamination speed is preferably 50 to 130 m / min, and more preferably 60 to 110 m / min. If the lamination speed is too slow, productivity is low, while if the lamination speed is too fast, the yield tends to decrease due to neck-in. Neck-in is a phenomenon in which the width of an extruded polyethylene resin film becomes smaller than the effective width of the T-die when the polyethylene resin is extruded into a film by a Petition 870220063643, dated 07 / 19 / 2022, pp. 67 / 108 48 / 83 T-die extruder. At this point, both ends of the film become thicker than the center. It is common to cut and remove both ends when the thickness at both ends deviates from the specification, but when the bottleneck is severe, the area that deviates from the specification increases and the yield decreases. [000131] In one embodiment, an air gap of 300 mm or less is preferred, and 200 mm or less is more preferred. If the air gap is too large, there is a tendency for neck-in to occur in the polyethylene resin and the yield to decrease. The air gap refers to the distance from an extrusion opening of the T-die to a laminating roll. It is preferable to perform the surface treatment of the polyethylene resin using ozone and / or oxygen gas while the polyethylene resin is passing through the air gap. By performing the surface treatment with ozone and / or oxygen gas, it is possible to promote the formation of an oxide film and improve adhesion to the substrate layer. There is no specific limit to the amount of ozone and / or oxygen gas processing, but from the point of view of promoting the oxidation of the polyethylene resin, 0.5 mg / m2 or more is preferred. (Process (ii): Preparation of the aqueous paint composition) [000132]In the above embodiment of the production method, the specific composition and method of preparation of the (ii) aqueous paint composition are as previously described in the aqueous paint composition embodiment. [000133]In one embodiment, such as an aqueous paint composition, it is preferable to prepare an aqueous paint composition (ii-1) containing a binder resin containing a resin Petition 870220063643, dated 07 / 19 / 2022, pp. 68 / 108 49 / 83 aqueous polyurethane and water. Here, the binder resin is preferably an aqueous polyurethane resin with an acid value, and more preferably it has been made aqueous by neutralization. Furthermore, the tensile strength at a percentage elongation of 50 to 4,000% is preferably from 0.1 mPa to 50 mPa. [000134] In another embodiment, instead of the aqueous ink composition (ii-1), it is preferable to prepare an aqueous ink composition (ii-2) containing: a binder resin containing an aqueous polyurethane resin with an acid value of 1 to 100 mg KOH / g; water; and at least one of a carbodiimide-based curing agent and one of a polyisocyanate-based curing agent. In this document, the polyurethane resin with an acid value of 1 to 100 mg KOH / g is preferably made aqueous by neutralization. (Process (iii): Formation of the printed layer) [000135]The formation of the printed layer (iii) is not particularly limited and a well-known technique can be applied. For example, when printing a white aqueous ink composition over the entire surface of the foamed layer-forming layer (B0) (low Mp resin film) as an undercoat, a coater, such as a bar coater, roll coater or reverse roll coater can be used. Several other printing methods can be applied. [000136]Among the various printing methods, a printing method based on flexographic printing or gravure printing is preferably applied. The aqueous ink compositions (ii-1) and (ii-2) of the embodiments described above can be used appropriately to Petition 870220063643, dated 07 / 19 / 2022, pp. 69 / 108 50 / 83 forming a printed layer based on these printing methods. In particular, when applying a flexographic printing method, it is possible to form the printed layer with good productivity and high yield. A representative example of a flexographic printing method is described below. (Flexographic printing method) (1) Anilox roller [000137]An anilox roller can be used in a flexographic printing method. For example, a cell-etched ceramic anilox roller, a chrome-plated anilox roller, or similar can be used. [000138]To obtain a printed layer (printed item) with excellent dot reproducibility, an anilox roller with a number of lines five times or more, preferably six times or more, the number of lines on a plate used during printing is used. For example, if the number of lines on the plate used is 75 lpi, an anilox roller with a number of lines of 375 lpi or more is required. Furthermore, if the number of lines on the plate is 150 lpi, an anilox roller with a number of lines of 750 lpi or more is required. The capacity of the anilox roller can be from 1 to 8 cm³ / m², preferably from 2 to 6 cm³ / m², from the point of view of the drying and blocking properties of the aqueous ink composition used. (2) Flexographic plate [000139] In a flexographic printing method, a photosensitive resin plate for which ultraviolet curing with a UV light source is used can be used as a plate. An elastomer material plate for which is Petition 870220063643, dated 07 / 19 / 2022, pp. 70 / 108 51 / 83 using a direct laser engraving system can also be used as a plate. Regardless of the method used to form the image portion of the flexographic plate, a plate with a screening line count of 75 lpi or more is used. An appropriate material can be used for a sleeve or padded tape to which the plate is glued. (3) Printer [000140]Specific examples of a flexographic printing press include a CI-type multicolor flexographic printing press and a unit-type multicolor flexographic printing press. Specific examples of the ink supply system include a chamber system and a two-roll system. A printing press that can be applied to a flexographic printing method can be selected and used appropriately. [000141]In one embodiment, the printed layer preferably includes a plurality of layers. The printed layer may have an undercoat layer covering the entire surface of the foam-forming layer (B0), and a print pattern provided on at least a portion of the surface of the undercoat layer. For example, the undercoat layer is composed of a white water-based ink composition and the print pattern is formed by a colored water-based ink composition. [000142] In one embodiment, the thickness of the printed layer is preferably adjusted so that the film thickness of a dry coating film is from 0.5 to 5.0 μm from the point of view of the printed layer's ability to suppress foaming and abrasion resistance. The film thickness of the printed layer (coating film) Petition 870220063643, dated 07 / 19 / 2022, pp. 71 / 108 52 / 83 dry) can be more preferably from 0.5 to 4.0 μm and can be even more preferably from 0.5 to 3.5 μm. In this document, when the printed layer is composed of a plurality of layers, the film thickness of the printed layer is preferably adjusted so that the thickness of the entire printed layer is within the above ranges. [000143] In another embodiment, the printed layer may include a plurality of layers and, preferably, has a transparent layer as the outermost layer. The transparent layer may be composed using a transparent ink composition that does not contain pigment. In one embodiment, the transparent ink composition may be composed similarly to the aqueous ink compositions described previously (ii-1) and (ii-2), except that a pigment is not included. [000144]When a transparent layer is provided, the abrasion resistance, ethanol resistance, and water abrasion resistance of the printed surface can be easily improved. In one embodiment, the thickness of the transparent layer film (dry film thickness) is preferably 0.1 to 3.0 μm, more preferably 0.1 to 2.5 μm, and even more preferably 0.1 to 2.0 μm. In this document, when the printed layer has a transparent layer, an adjustment is preferably made so that the thickness of the entire printed layer, including the thickness of the transparent layer, is in the range of 0.5 to 5.0 μm. [000145]When the printed layer includes a plurality of layers, a water-based ink that constitutes at least one of Petition 870220063643, dated 07 / 19 / 2022, pp. 72 / 108 53 / 83 plurality of layers preferably contains a binder resin containing a polyurethane resin and a curing agent. In one embodiment, a water-based paint composition constituting at least the undercoat and / or the outermost layer preferably contains a binder resin containing a polyurethane resin and a curing agent. It is more preferably that the undercoat (white) paint layer and the outermost layer (paint layer or transparent layer) are formed using the water-based paint composition, and it is more preferably that the entire plurality of layers is formed using the water-based paint composition. (Process (iv): Foamed layer formation (B)) [000146]In the formation of the foamed layer (B) by heating in process (iv), the appropriate heating temperature and heating time vary depending on the characteristics of the paper substrate and the thermoplastic resin film used. A person skilled in the art can determine the combined conditions of the ideal heating temperature and heating time according to the materials used, such as the thermoplastic resin film. The heat treatment is not particularly limited, but is generally carried out in the container forming process. If the heating temperature during the heat treatment is too low, it is not possible to obtain sufficient foam, and if the heating temperature is too high, the foam cells tend to combine and cause bubble formation. [000147]When the foam layer forming the foam layer is composed of a low-density polyethylene film, the heating temperature is not particularly limited, Petition 870220063643, dated 07 / 19 / 2022, pp. 73 / 108 54 / 83 but may preferably be 100 to 125°C, and may more preferably be 110 to 120°C. The heating time may be adjusted accordingly according to the heating temperature, but 3 to 10 minutes is preferable and 5 to 7 minutes is more preferable. In one embodiment, when the foamed layer forming layer is composed of a low-density polyethylene film and the printed layer is formed on the same using the aqueous ink composition (ii-1) or (ii-2) described above, the heating temperature is preferably set to 110 to 123°C and the heating time to 5 to 7 minutes. It is more preferable to set the heating temperature to 115 to 121°C and the heating time to 5 to 7 minutes. When heating is carried out under the above conditions, it is easy for the foam formation of the foamed layer that occurs during thermal processing to be adequately controlled by the printed layer. [000148]Any means can be used as a heating medium, such as hot air, electric heating, and electron beams. When heating is carried out using hot air, electric heating, or similar methods within a tunnel equipped with transport means using a conveyor, a large amount of heat treatment can be performed at low cost. <4> Foamed paper container [000149] One embodiment refers to a foamed paper container provided with the foamed paper laminate of the embodiment described above. The foamed paper container is composed of a container body element and a bottom plate element, and the container body element is formed by Petition 870220063643, dated 07 / 19 / 2022, pp. 74 / 108 55 / 83 from the foamed paper laminate of the above embodiment. FIG. 1 is a perspective view illustrating the structure of a foamed paper container 10A obtained by performing heat treatment after assembly and container forming. As shown in FIG. 1, the foamed paper container 10A is composed of a container body element 10 and a bottom plate element 12 which are composed of a foamed paper laminate. In the container body member (foamed paper laminate) 10, a high Mp resin film forms an inner wall surface 10a of the container and a layer printed on a low Mp resin film (foamed layer) forms an outer wall surface 10b of the container. [000150]FIG. 2 is a schematic cross-sectional view illustrating an enlarged view of the part indicated by the reference character I of the foamed paper container body element illustrated in FIG. 1. The container body member (foamed paper laminate) 10 has, in order of the inner wall surface 10a of the container side (see FIG. 1), a high Mp resin film 20, a paper substrate 30, a low Mp resin film after foaming (foamed layer) 40 and a printed layer 50, in which the printed layer 50 has an undercoat layer 50a and a printing pattern 50b. [000151]The process of forming the foamed paper container can be carried out using a well-known technique. For example, a foamed paper laminate (foamed paper laminate before heating) in which a printed layer has been formed is first perforated in a predetermined shape along a mold to obtain Petition 870220063643, dated 07 / 19 / 2022, pp. 75 / 108 56 / 83 a container body member. Similarly, a bottom plate material is perforated into a predetermined shape to obtain a bottom plate member. Then, the container body member and the bottom plate member are assembled and formed into the shape of a container using a conventional container fabrication apparatus. The assembly and forming of a container using a container fabrication apparatus is carried out in such a way that the high Mp resin film of the container body member forms the inner wall surface, the low Mp resin film forms the outer wall surface, and the laminated surface of the bottom plate member comes to the inner side.After the container is assembled and formed by the container-making apparatus in this manner, heat treatment is performed, the low Mp resin film foams and forms a foamed layer (thermal insulation layer), and a foamed paper container with thermal insulation properties can be obtained. [000152] In one embodiment, where the inner wall surface and the outer wall surface of the foamed paper container body are composed of a polyethylene film, it is preferable that one surface of the paper substrate (the inner wall surface of the container) be laminated with a medium or high-density polyethylene film, and the other surface (the outer wall surface of the container) be laminated with a low-density polyethylene film. The thickness of each film to be laminated onto the paper substrate is not particularly limited. However, it is preferable that the thickness of the low Mp resin film that constitutes the outer wall surface of the Petition 870220063643, dated 07 / 19 / 2022, pp. 76 / 108 57 / 83 The container body must be properly fitted so that the film layer, after foaming, acts as a heat-insulating layer when the film is foamed. [000153] For example, when the surface of the outer wall of the container body is composed of a low-density polyethylene film, the thickness of the film to be laminated onto the paper substrate can be from 40 to 150 μm. However, when the surface of the inner wall of the container body is composed of a medium or high-density polyethylene film, the thickness of the film to be laminated onto the paper substrate is not particularly limited. However, it is preferable to adjust the film thickness appropriately to ensure resistance to penetration of the contents when used as a heat-insulating foamed paper container. The thickness of the film to be laminated onto the paper substrate varies according to the resinous material of the film used, so it is desirable that a person skilled in the art adjust the film thickness appropriately considering the characteristics of the resinous material. Examples [000154]The present invention is described below in more detail using examples, but the present invention is not limited to these examples. Note that, unless otherwise indicated, part and % mentioned below refer to parts by mass and % by mass, respectively. <1> Measurement methods for various resources [000155]The various characteristics of binder resins and aqueous paint compositions described below represent values ​​obtained through measurement methods. Petition 870220063643, dated 07 / 19 / 2022, pp. 77 / 108 58 / 83 described below. (Glass transition temperature) [000156]Each of the aqueous polyurethane resin solutions obtained in the synthesis examples described below was coated onto a polyethylene substrate and then dried at 40°C for three days to obtain a dry coating film with a thickness of 0.5 mm. The peak temperature of the tangent loss of each dry coating film was measured using an automatic dynamic viscoelastometer (DDV-GP series (RHEOVIBRON) manufactured by A&D Company, Limited) and was defined as Tg (°C). Measurements were performed over a temperature range of 120°C to 40°C at a temperature rise rate of 10°C / min. (Percentage of elongation and tensile strength of the binder resin) [000157] Each of the aqueous polyurethane resin solutions obtained in the synthesis examples described below was dried to prepare coating film test samples (0.30 mm thick, 5.0 mm wide and 20.0 mm long). The percentage of elongation and tensile strength of each sample were measured using a small-sized tensile tester manufactured by Intesco Co., Ltd. The measurements were performed under conditions of a tensile rate of 100 mm / min and an ambient temperature of 25°C. [000158]Note that, for an embodiment in which the aqueous paint composition contains a curing agent, the binder resin and the curing agent were combined in a similar mixing ratio in the aqueous paint composition and a coating film test sample (0.30 mm thick, 5.0 mm wide, 20.0 mm long) Petition 870220063643, dated 07 / 19 / 2022, pp. 78 / 108 Sample 59 / 83 was prepared. Using this sample, the elongation percentage and the tensile strength of the binder resin (cured product) were measured according to the same method described above. (Residual percentage of the printed layer) [000159]The residual percentage of the printed layer is a test to evaluate the ethanol resistance of the printed layer (surface of the foamed paper laminate) formed on the foamed paper, which was carried out as follows. [000160]First, a foamed paper laminate was cut to dimensions of 100 mm in length and 100 mm in width as a test piece (sample). The mass of the cut test piece was measured as the mass of the sample before immersion in ethanol. The test piece was then broken into fragments approximately 20 mm long and 20 mm wide for convenience in the immersion operation. [000161]Next, ethanol (25°C) and the broken test piece were placed in a container so that the mass ratio of ethanol to the test piece was 100:4.5, and the test piece was immersed in ethanol. Immersion was carried out in ethanol at 25°C under conditions of 2 minutes with agitation of the test piece at a stirring speed of 100 rpm, followed by 30 minutes and then 1 minute under agitation of the test piece at a speed of 100 rpm. The test piece was removed and the mass of the test piece after drying was measured and taken as the mass of the sample after immersion. [000162]Furthermore, the residual percentage of the printed layer was calculated according to the formula below from the sample mass before immersion and the mass of Petition 870220063643, dated 07 / 19 / 2022, pp. 79 / 108 60 / 83 sample after immersion measured as described above. Residual percentage of the printed layer = (mass of the sample after immersion / mass of the sample before immersion) x 100 (Thickness of the printed layer film) [000163]The thickness of the printed layer film was determined from a scanning electron microscope (SEM) photograph (5,000x magnification) of a cross-section of the foamed paper laminate. Measurements were taken at five arbitrary locations on the printed layer, and the average of these measurements was used as the thickness of the printed layer film. (Number of foam cells) [000164]The printed layer of the foamed paper laminate was removed with methyl ethyl ketone (MEK) to expose the surface of the foamed thermoplastic resin layer (foamed layer). Then, the surface of the foamed layer was observed (25x magnification) using an optical microscope (AZ100M manufactured by Nikon Corporation), the number of independent cells present within a strip demarcated by a certain length in the vertical and horizontal (XY) directions was obtained, and a calculated value was obtained as the number of independent cells per 1 cm². Observations were made at five arbitrary locations, and the average of these observations was used as the number of foamed cells. (Foamed layer film thickness) [000165]The thickness of the foamed layer film (B) was determined by observing a cross-section of the foamed paper laminate using an optical microscope photograph and measuring the height of the top surface of the substrate. Petition 870220063643, dated 07 / 19 / 2022, pages 80 / 108 61 / 83 paper up to the bottom surface of the printed layer. Furthermore, the film thickness before foaming corresponds to the film thickness of the foamed layer and was therefore taken as a value obtained by measuring the thickness of the low-density polyethylene resin film formed as the foamed layer. (Binder resin) (Example of Synthesis 1) Polyurethane resin (A) [000166]In a reactor equipped with a reflux condenser, a drop funnel, a gas inlet tube, a stirrer, and a thermometer, 328.16 parts of poly(3-methyl-1,5-pentane adipato)diol (PMPA 2000, number average molecular weight 2000), 10.0 parts of polyethylene glycol (PEG 2000, number average molecular weight 2000), 57.81 parts of dimethylolbutanoic acid (DMBA), and 350 parts of methyl ethyl ketone (MEK) were added while introducing gaseous nitrogen. While these were being mixed and stirred, another 200.76 parts of isophorone diisocyanate (IPDI) were added dropwise over 1 hour. These were then reacted at reflux temperature for 6 hours to form a terminal isocyanate prepolymer. The reaction solution was then cooled to 30°C, 100 parts of isopropyl alcohol were added, and a solvent solution of terminal isocyanate prepolymer was obtained. [000167]A mixed liquid of 28.21 parts of 2-aminoethylethanolamine (AEA) and 150 parts of isopropyl alcohol (IPA) was gradually added at room temperature (25°C) to the obtained terminal isocyanate prepolymer and allowed to react at 40°C for three hours to thus Petition 870220063643, dated 07 / 19 / 2022, pp. 81 / 108 62 / 83 obtain a solvent-type polyurethane resin solution. [000168]Next, 23.69 parts of 28% ammonia water and 1,800 parts of ion exchange water were gradually added to the solvent-type polyurethane resin solution for neutralization, thus obtaining a polyurethane resin solution that was made aqueous. Furthermore, MEK and IPA in the aqueous polyurethane resin solution were removed by distillation under reduced pressure, and then water was added to adjust the solids content to 25%. [000169]An aqueous solution (25% solids content) of polyurethane resin (A) with an acidity index of 35 mg KOH / g and a weight-average molecular weight of 35,000 was obtained as described above. The percentage elongation, tensile strength, and other characteristics of the polyurethane resin (A) were measured according to the methods described previously. The results are shown in Table 1. (Synthesis Examples 2 to 8) [000170] Aqueous solutions of polyurethane resins (B) to (H), each with 25% solids content (hereinafter sometimes abbreviated as polyurethane resins (B) to (H)), were obtained in the same manner as in Synthesis Example 1, except that the raw materials and mixing quantities described in Synthesis Example 1 were altered to achieve the characteristics given in Table 1, according to the synthesis method described in Japanese Unexamined Patent Application Publication No. 2018-184512. The percentage elongation, tensile strength, and other characteristics of the polyurethane resins (B) to (H) were measured according to the methods described above, and the results are Petition 870220063643, dated 07 / 19 / 2022, pp. 82 / 108 63 / 83 shown in Table 1. Petition 870220063643, dated 07 / 19 / 2022, pp. 83 / 108 64 / 83 [Table 1] Table 1 Polyurethane Resin Synthesis Example 1 Synthesis Example 2 Synthesis Example 3 Synthesis Example 4 Synthesis Example 5 Synthesis Example 6 Synthesis Example 7 Synthesis Example 8 Resin A Resin B Resin C Resin D Resin E Resin F Resin G Resin H Resin Characteristics Resin Elongation Percentage (%) 450 2,000 800 900 300 1,500 800 410 Resin Tension (mPa) 8 2 13 7 15 0.3 40 10 Glass Transition Temperature (°C) -44 -60 -50 -34 -5 -54 -20 -55 Acid Value (mg KOH / g) 35 35 35 35 35 35 35 35 Weight-average molecular weight 35,000 35,000 35,000 50,000 35,000 35,000 35,000 20,000 Petition 870220063643, dated 07 / 19 / 2022, pages 84 / 108 65 / 83 <2> Examples of water-based paint composition production (Production Example 1) White paint production (W1) [000171]According to the composition shown in Table 2, 10 parts of aqueous polyurethane resin solution (A), 20 parts of aqueous polyurethane resin solution (B), 40 parts of white pigment (titanium dioxide, TITANIX JR808 (manufactured by TAYCA Co., Ltd.)), 0.1 part of antifoaming agent, 0.2 part of adipic acid dihydrazide (ADH), 1 part of N-propanol and 5 parts of water were stirred and mixed and then subjected to dispersion treatment in a sand mill. Then, the mixture obtained by the dispersion treatment was further added to 4 parts of aqueous polyurethane resin solution (A), 14 parts of aqueous polyurethane resin solution (B) and 6 parts of water, and the mixture was stirred and mixed to obtain a white paint (W1). (Production Examples 2 to 9) Production of white paints (W2) to (W9) [000172]The white paints (W2) to (W9) were all obtained in the same way as in the production method described in Production Example 1, except that the two types of aqueous polyurethane resin solutions used in Production Example 1 were changed according to the compositions given in Table 2. [000173]Note that the binder resins given in Table 2 are as follows. [000174]Polyurethane resins A to H: Aqueous solutions (each with 25% solids content) of polyurethane resins (A) to (H) prepared in Synthesis Examples 1 to 8. Petition 870220063643, dated 07 / 19 / 2022, pages 85 / 108 66 / 83 [000175] Polyurethane resin I: Product name UREARNO W321 (aqueous solution of a polyurethane resin with a resin elongation percentage of 600% and a tensile strength of 7.0 mPa) manufactured by Arakawa Chemical Industries, Ltd. [000176]Acrylic resin: Product name Joncryl 7100 (emulsion of an acrylic resin with an average molecular weight of 200,000, glass transition temperature of -10°C, acid value of 51 mg KOH / g, resin elongation percentage of 180% and tensile strength of 6.5 mPa) manufactured by BASF Corporation. [000177]Vinyl chloride resin: Product name VINYBLAN 700 (vinyl chloride resin emulsion with a glass transition temperature of 70°C and an acid value of 57 mg KOH / g) manufactured by Nissin Chemical Co., Ltd. (Production Example 10) Indigo paint production (B1) [000178]According to the composition shown in Table 2, 20 parts of aqueous polyurethane resin solution (B), 20 parts of aqueous polyurethane resin solution (C), 20 parts of indigo pigment (LIONOL BLUE FG-7358-G (manufactured by TOYOCOLOR Co., Ltd.)), 0.10 parts of antifoaming agent, 0.20 parts of ADH, 2.5 parts of N-propanol and 10 parts of water were stirred and mixed and then subjected to dispersion treatment in a sand mill. Then, the mixture obtained by the dispersion treatment was further supplemented with 4 parts of aqueous polyurethane resin solution (B), 16 parts of aqueous polyurethane resin solution (C) and 8 parts of water, and the mixture was stirred and mixed to obtain an indigo paint (B1). (Production Examples 11 to 18) Production of indigo inks (B2) to (B9) Petition 870220063643, dated 07 / 19 / 2022, pp. 86 / 108 67 / 83 [000179]The indigo inks (B2) to (B9) were all obtained in the same way as in the production method described in Production Example 10, except that the two types of aqueous polyurethane resin solutions used in Production Example 10 were changed to the compositions given in Table 2. (Production Example 19) Production of transparent ink (C1) [000180] According to the composition shown in Table 2, 82 parts of aqueous polyurethane resin solution (C), 0.1 part of antifoaming agent, 0.2 part of ADH, 1 part of N-propanol and 17 parts of water were stirred and mixed to obtain a transparent ink (C1) for overprinting. (Production Examples 20 to 27) Production of transparent inks (C2) to (C9) [000181]The transparent paints (C2) to (C9) were all obtained in the same way as in the production method described in Production Example 19, except that the aqueous polyurethane resin solution described in Production Example 19 was changed to the composition given in Table 2. Petition 870220063643, dated 07 / 19 / 2022, pp. 87 / 108 68 / 83 [Table 2] (Continued on the next page) Table 2 Composition of water-based paint 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 W1 W2 W3 W4 W5 W6 W7 W8 W9 B1 B2 B3 B4 B5 B6 Glutinating resin Polyurethane resin A 14.4 7.2 Polyurethane resin B 33.6 16.8 23.7 11.9 Polyurethane resin C 35.5 17.7 Polyurethane resin D 48.0 59.2 Polyurethane resin E 48.0 59.2 Polyurethane resin F 48.0 59.2 Polyurethane resin G 48.0 24.0 59.2 29.6 Polyurethane resin H 48.0 Polyurethane resin I 48.0 Acrylic resin 48.0 Vinyl chlorine resin Pigment Titanium oxide 40.0 40.0 40.0 40.0 40.0 40.0 40.0 40.0 40.0 Phthalocyanine from indigo cobre 20.0 20.0 20.0 20.0 20.0 20.0 Additive Anti-foaming agent 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 ADH 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 Solvent Water 10.7 10.7 10.7 10.7 10.7 10.7 10.7 10.7 10.7 18.0 18.0 18.0 18.0 18.0 18.0 n-propanol 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 2.5 2.5 2.5 2.5 2.5 2,5 Total 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100, [Table 2] (Continued from the previous page) Table 2 Water-based paint composition 16 17 18 19 20 21 22 23 24 25 26 27 Petition 870220063643, dated 07 / 19 / 2022, pages 88 / 108 69 / 83 B7 B8 B9 C1 C2 C3 C4 C5 C6 C7 C8 C9 Binder resin Polyurethane resin A Polyurethane resin B Polyurethane resin C 81.7 40.9 73.5 Polyurethane resin D 81.7 Polyurethane resin E 81.7 Polyurethane resin F 81.7 Polyurethane resin G 81.7 40.8 Polyurethane resin H 59.2 81.7 Polyurethane resin I 59.2 Acrylic resin 59.2 81.7 Vinyl chloride resin 8.2 Pigment Titanium oxide Copper phthalocyanine indigo 20.0 20.0 20.0 Additive Antifoam agent 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 ADH 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 Solvent Water 18.0 18.0 18.0 17.0 17.0 17.0 17.0 17.0 17.0 17.0 17.0 17.0 n-propanol 2.5 2.5 2.5 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 Total 100 100 100 100 100 100 100 100 100 100 100 100 Petition 870220063643, dated 07 / 19 / 2022, pp. 89 / 108 70 / 83 <3> Example of foamed paper laminate production (1) Example of foamed paper material production [000182]A foamed paper material was produced by the following processes: (process 1) extrusion lamination of a medium-density polyethylene resin (M) to form a water vapor blocking layer on one side of a paper substrate; and (process 2) followed by extrusion lamination of a low-density polyethylene resin (L) on the other side (non-laminated side) of the paper substrate. [000183]The various conditions in process 1 and process 2 are as follows. (Process 1) Paper substrate: water content 23 kg / m3, basic weight 320 kg / m3 Medium density polyethylene resin (M): Petrosen LW04-1 manufactured by Tosoh Corporation, MFR 4.3 g / 10 min, density 940 kg / m3 Extrusion temperature (mold exit temperature T): 320°C Pickup speed (lamination speed): 50 m / min Air gap: 130mm Thickness: 40 μm (thickness of the center of the polyethylene resin layer) (Process 2) Low-density polyethylene resin (L): described later Extrusion temperature (mold exit temperature T): 310°C Petition 870220063643, dated 07 / 19 / 2022, pp. 90 / 108 71 / 83 Pickup speed (rolling speed): 60 m / min Air gap: 130 mm [000184]Note that the low-density polyethylene resin (L) used in process 2 above serves as the foam-forming layer (B0). To produce the foamed paper material, low-density polyethylene resin (L) was used, low-density polyethylene resin (L2) in Example 18 and otherwise low-density polyethylene resin (L1). The details of low-density polyethylene resins (L1) and (L2) are as follows. Low-density polyethylene resin (L1): Petrosen 07C03C manufactured by Tosoh Corporation, density 918 kg / m3, melting point 106°C, MFR 15 g / 10 min Low-density polyethylene resin (L2): NOVATEC LDLC720 manufactured by Japan Polyethylene Corporation, density 922 kg / m3, melting point 110°C, MFR 9 g / 10 min (2) Example of printed layer formation production on foamed paper material (foamed paper laminate before foaming) [000185]The previously prepared white inks (W1 to W9), indigo inks (B1 to B9) and transparent inks (C1 to C9) were used to form a printed layer on the foamed paper material as described below. (Example 1) [000186]As described in Table 3, the printing inks were obtained by adding 3 parts by mass of CARBODILITE SV-02 (manufactured by Nisshinbo Chemical Inc.) as a carbodiimide-based curing agent to 100 parts Petition 870220063643, dated 07 / 19 / 2022, pp. 91 / 108 72 / 83 by mass of white ink (W1), indigo ink (B1) and transparent ink (C1), respectively. The curing agent above had a chemical formula weight per 1 mol of carbodiimide groups of 430 and a solids content of 40% by mass. [000187]A printed layer was formed on the low-density polyethylene resin (L) of the foamed paper material by overprinting in the order of printing ink (W1), printing ink (B1) and printing ink (C1) using an anilox roller and a resin plate, using a center-press flexographic printer (CI). The printing speed was 150 m / min. (Examples 2 to 19 and Comparative Examples 1 to 4) [000188] As described in Table 3, for embodiments in which a curing agent is added to white ink, indigo ink, and transparent ink, the respective printing inks were obtained by additional addition of the curing agent. Note that the amount of CARBODILITE SV02 (manufactured by Nisshinbo Chemical Inc.) added was 5.0 parts in Example 3, 1.0 part by mass in Example 12, 5.0 parts by mass in Example 13, and otherwise 3 parts by mass as in Example 1. In Example 11, Takenate WD-725 (manufactured by Mitsui Chemicals Inc., aqueous isocyanate-based curing agent, 50% solids content by mass) was used as the curing agent, and the amount added was 3 parts by mass. The printed layer was formed by overprinting according to the same method as Example 1, except that each printing ink was used in combination as described in Table 3. (3) Example of foamed paper laminate production [000189]A foamed paper material with a layer Petition 870220063643, dated 07 / 19 / 2022, pp. 92 / 108 73 / 83 printed material produced as described above (foamed paper laminate before foaming) was heat treated under the following conditions to cause the low-density polyethylene resin layer (L) to foam and form a foamed layer, thus producing a foamed paper laminate (laminate after foaming). Note that in the examples and comparative examples other than Examples 14 and 15 and Comparative Example 4, the heat treatment was performed under standard conditions. Standard conditions: Preheat for 6 minutes in an oven at 120°C. Example 14: Heating for 9 minutes in an oven at 120°C. Example 15: Heating for 6 minutes in an oven at 122°C. Comparison example 4: Heating for 6 minutes in an oven at 124°C. <4> Evaluation of foamed paper laminate [000190]Several characteristics of the foamed paper laminates of Examples 1 to 19 and Comparative Examples 1 to 4 produced as described above were evaluated according to the methods described below. The respective results are shown in Table 3. <Adaptabilidade da espuma> [000191] For each surface of the foamed paper laminates of Examples 1 to 19 and Comparative Examples 1 to 4, the level difference between the section printed with white ink and the section printed with indigo ink after heat treatment (after the formation of low Mp film foam) was felt by touch, and the degree of depression of the section printed with indigo ink was evaluated according to the following criteria. A higher numerical value in the evaluation indicates a better Petition 870220063643, dated 07 / 19 / 2022, pp. 93 / 108 74 / 83 foam adaptability and a flatter printed surface. (Evaluation criteria) [000192]5: It was hardly noticeable that there was a difference in level compared to the section printed in white ink. [000193]4: A slight difference in level with the section printed in white ink was perceived. [000194]3: A level difference with the section printed in white ink was perceived to some extent. [000195]2: A significant difference in level compared to the section printed in white ink was observed. [000196]1: A significant difference in level with the section printed in white ink was observed.<Aparência externa de espuma: bolhas> [000197]The printed surfaces of the foamed paper laminates of Examples 1 to 19 and the foamed paper laminates of Comparative Examples 1 to 4 were visually observed. The evaluation criteria were as follows. Note that the results shown in Table 3 are mode values ​​in the results of the observation and evaluation of 10 readily prepared samples of foamed paper laminates. In case of a plurality of mode values, the value that resulted in the lowest evaluation was adopted. (Evaluation criterion) [000198]5: No bubbles (no bubbles can be seen). [000199]4: A bubble with a principal axis smaller than 5 mm was present per 100 cm2. [000200]3: Two bubbles with a principal axis of less than 5 mm were present per 100 cm2. Petition 870220063643, dated 07 / 19 / 2022, pp. 94 / 108 75 / 83 [000201]2: Three to five bubbles with a principal axis smaller than 5 mm were present per 100 cm2. Or, one bubble with a principal axis of 5 to 20 mm was present per 100 cm2. [000202]1: Six bubbles with a major axis smaller than 5 mm were present per 100 cm2. Or, two or more bubbles with a major axis of 5 to 20 mm were present per 100 cm2. Or, one or more bubbles with a major axis greater than 20 mm were present per 100 cm2. [000203]Note that if a plurality of bubbles with different principal axes were present together, the lowest rating was adopted. Specifically, in the case of two bubbles with a principal axis less than 5 mm and one bubble with a principal axis of 5 to 20 mm per 100 cm2, the rating of 2 is adopted. <Aparência externa de espuma: rachaduras> [000204]The printed surfaces of the foamed paper laminates of Examples 1 to 19 and Comparative Examples 1 to 4 were visually observed in a manner similar to the evaluation of bubble formation. The evaluation criteria were as follows. Note that the results shown in Table 3 are mode values ​​in the results of the observation and evaluation of 10 readily prepared samples of foamed paper laminates. In case of a plurality of mode values, the value that resulted in the lowest evaluation was adopted. (Evaluation criteria) [000205]5: No crack (no crack can be seen). [000206]4: A crack less than 2 mm long Petition 870220063643, dated 07 / 19 / 2022, pp. 95 / 108 76 / 83 was present per 100 cm2. [000207]3: Two to four cracks less than 2 mm long were present per 100 cm2. [000208]2: Five to ten cracks less than 2 mm long were present per 100 cm2. Or, one crack 2 to 5 mm long was present per 100 cm2. [000209]1: Eleven or more cracks less than 2 mm in length were present per 100 cm2. Or, two or more cracks 2 to 5 mm in length were present per 100 cm2. Or, one or more cracks larger than 5 mm in length were present per 100 cm2. [000210]Note that if a plurality of cracks with different lengths were present together, the lowest rating was adopted. Specifically, in the case of a 1 mm long crack and a 4 mm long crack per 100 cm2, the rating of 2 was adopted.<Resistência ao etanol> [000211] For the foamed paper laminates of Examples 1 to 19 and Comparative Examples 1 to 4, unbleached muslin (JIS L 0803) containing 70% ethanol (ethanol:water = 70:30) in a friction element was moved back and forth once while applying a load against the surface of the printed layer (coating film) on the low-melting-point foamed film due to heat treatment. When the unbleached muslin was moved back and forth, a 200 g load was applied using a Gakushin-type friction tester (manufactured by TESTER SANGYO Co., Ltd.). Ethanol resistance was then evaluated by visually observing the coating film and calculating the percentage of the area where the coating film (ink) adhered. Petition 870220063643, dated 07 / 19 / 2022, pages 96 / 108 77 / 83 detached, based on the total area of ​​the coating film before testing. The evaluation criteria were as follows. (Evaluation criteria) [000212]5: Paint peeling is less than 30%. [000213]4: The paint peeling is 30% or more and less than 40%. [000214]3: The paint peeling is 40% or more and less than 60%. [000215]2: The paint peeling is 60% or more and less than 70%. [000216]1: The paint is peeling off by 70% or more.<Resistência à abrasão> [000217] For the foamed paper laminates of Examples 1 to 19 and Comparative Examples 1 to 4, a surface printed with white ink or a surface printed with white ink and transparent ink (coating film surface) of each laminate was used as the friction element. The coating film surface was moved back and forth once under a 200 g load using a Gakushin-type friction tester (manufactured by TESTER SANGYO Co., Ltd.). Abrasion resistance was evaluated based on the degree of color transfer from the indigo ink to the white ink-printed surface. (Evaluation criteria) [000218]5: There was no ink color transfer. [000219]4: There was a slight transfer of ink color (less than 1%). [000220]3: There was ink color transfer (1% or more, less than 10%). [000221]2: There was significant color transfer from Petition 870220063643, dated 07 / 19 / 2022, pp. 97 / 108 78 / 83 ink (10% or more, less than 30%). [000222]1: There was a large amount of ink color transfer (30% or more).<Propriedades de isolamento térmico> [000223]Thermal resistance was evaluated by placing a foamed paper laminate on a hot plate heated to 90°C with the foamed surface facing upwards and measuring the temperature of the foamed surface (non-contact surface) after 4 minutes. More specifically, the temperatures of 10 samples of foamed paper laminates were measured after heating and the time period described above, and the average temperature of these samples was obtained. From the average temperature obtained, the thermal resistance was evaluated according to the following evaluation criteria. (Evaluation criteria) [000224]5: The surface temperature of the foam was below 80°C. [000225]4: The surface temperature of the foam was 80°C or higher and below 82°C. [000226]3: The surface temperature of the foam was 82°C or higher and below 84°C. [000227]2: The surface temperature of the foam was 84°C or higher and below 88°C. [000228]1: The surface temperature of the foam was 88°C or higher. Petition 870220063643, dated 07 / 19 / 2022, pp. 98 / 108 79 / 83 [Table 3-1] Table 3 Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Example 8 Example 9 Example 10 Example 11 Example 12 Printed layer White printed layer (ink name) W1 W2 W1 W1 W1 W1 W1 W1 W1 W1 W1 Printed layer (ink name) B1 B2 B1 B1 B1 B1 B3 B1 B1 B1 B4 Transparent printed layer (ink name) C1 C2 Nenhum C1 C1 C7 C8 C3 C1 C1 C1 C4 Type of curing agent Present (Y) or not (N) (white / indigo / transparent) Carbohydrate (Y / Y) Carbodiimide (N / Y / -) Carbodiimide (Y / N / Y) Carbodiimide (N / N / Y) Carbodiimide (Y / N / Y) Carbodiimide (Y / N / Y) Carbodiimide (Y / N / Y) Carbodiimide (Y / N / Y) Carbodiimide (Y / N / Y) Isodiimide (Y / N / Y) Carbodiimide (Y / N / Y) Printed layer characteristics Binder resin elongation (%) 597 900 1081 814 1172 811 621 247 814 814 910 1367 Binder stress (mPa) 18.7, 10.61 12.5 15.7 10.7 18.3 16.4 16.4 12.0 0,4. Residual percentage of the printed layer (%) 95 50 50 75 55 75 70 75 75 75 55 60 Glass transition temperature (°C) -55 -35 -55 -55 -55 -50 -40 -5 -55 -55 -55 -55 Printed layer film thickness (µm) 2 2 1.5 2 2 2 2 2 6 0.3 2 2 .MFR ink (g / 10 min) 15 15 15 15 15 15 15 15 15 15 15 15 Density (kg / m3) 918 918 918 918 918 918 918 918 918 918 918 918 Number of cells Foamed (cells / 1cm2) 1398 1421 1411 1432 1404 1420 1439 1415 1451 1394 1406 1389 Characteristic layer thickness Film thickness before foam formation (pm) 70 70 70 70 70 70 70 70 70 70 70 70 Film thickness after foam formation (pm) 650 710 690 750 700 750 640 600 620 950 800 920 Characteristic evaluation Adaptability of foam formation 5 5 5 5 5 5 4 2 2 3 5 3 External appearance of foam formation (bubbles) 5 5 5 5 5 5 5 5 5 5 5 2 External appearance of foam formation (cracks) 5 5 5 5 5 5 5 3 5 2 5 5 Ethanol resistance 5 3 3 5 3 5 5 5 5 2 3 4, Petition 870220063643, dated 07 / 19 / 2022, pp. 99 / 108 80 / 83 Abrasion resistance 5 4 3 5 5 5 5 5 4 2 4 3 Thermal insulation properties 5 5 5 5 5 5 4 2 2 5 5 5 [Table 3-2] Table 3 (Continued) Example 13 Example 14 Example 15 Example 16 Example 17 Example 18 Example 19 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Printed Layer White Printed Layer (ink name) W5 W1 W1 W1 W1 W1 W6 W7 W8 W9 W1 Indigo Printed Layer (ink name) B5 B1 B1 B1 B1 B1 B6 B7 B8 B9 B1 Transparent Printed Layer (ink name) C5 C1 C1 C1 C1 C1 C6 C8 None C9 C1 Curing Agent Type Present (Y) or not (N) (white / indigo / transparent) Carbodiimide (Y / N / Y) Carbodiimide (Y / N / Y) Carbodiimide (Y / N / Y) Carbodiimide (Y / N / Y) Carbodiimide (Y / N / Y) Carbodiimide (Y / N / Y) Carbodiimide (Y / N / Y) Carbodiimide (Y / N / Y) None None Carbodiimide (Y / N / Y) Characteristics of the printed layer Elongation of the binder resin (%) 500 814 814 814 814 814 657 140 600 410 814 Tensile strength of the binder resin (mPa) 55.3 16.4 16.4 16.4 16.4 16.4 35.7 5.1 7.0 10.0 16.4. Residual percentage of the printed layer (%) 80 75 75 75 75 75 75 65 40 45 75 Glass transition temperature (°C) -20 -55 -55 -55 -55 -55 -40 -10 - -55 -55 Printed layer film thickness (μκι) 2 2 2 2 2 2 2 2 1.5 2 2 Foamed layer characteristics MFR (g / 10 min) 15 15 15 15 15 9 15 15 15 15 15 Density (kg / m3) 918 918 918 918 918 922 918 918 918 918 918 Number of foamed cells (cells / 1cm2) 1408 1212 1024 1572 1026 1467 1399 1417 1392 1401 914 Film thickness before foam formation (μσι) 70 70 70 90 50 70 70 70 70 70 70 Film thickness after foam formation 580 760 780 850 690 630 640 960 700 730 820. Petition 870220063643, dated 07 / 19 / 2022, pages 100 / 108 Evaluation of foam characteristics (μκι) Adaptability of foam formation External appearance of the 4 4 ​​4 foam formation (bubbles) External appearance of foam formation (cracks) Resistance to 5% ethanol Abrasion resistance Thermal insulation properties 2 5 5 5 2 4 3 5 3 4 3 5 3 5 5 5 5 5 5 5 5 4 3 5 3 5 4 1 5 5 2 5 5 1 5 5 1 5 5 2 5 5 1 5 5 5 1 1 5 5 5 5 2 2 5 4 4 2 5 5 1 Petition 870220063643, dated 07 / 19 / 2022, pages 101 / 108 82 / 83 [000229]From the results shown in the examples and comparative examples above, it can be seen that it is possible to obtain excellent external foam appearance, abrasion resistance, thermal resistance, and ethanol resistance using foamed paper laminates (Examples 1 to 19) in which the residual percentage of the printed layer after immersion in ethanol at 25°C is 50% by mass or more and the number of foam cells in the foamed layer is 1,000 cells / 1 cm2 or more. Furthermore, as is clear from a comparison between Examples 1 to 19 and Comparative Example 1, it can be seen that it is preferable to include at least one polyurethane resin as a binder resin to compose a water-based ink composition to form the printed layer.As seen in Comparative Example 1, when only an acrylic resin is used as the binder resin (a polyurethane resin is not included), the elongation percentage and the resin tension become lower than when a polyurethane resin is used, and the foam adaptability and external foam appearance decrease considerably. Furthermore, as is clear from a comparison between Examples 1 to 19 and Comparative Examples 2 and 3, it can be seen that by adjusting the weight-average molecular weight of the polyurethane resin and other compositions, it is possible to obtain excellent foam adaptability and external foam appearance, and also to improve the ethanol and abrasion resistance of the printed layer. [000230] From the description above, it is clear that a wide variety of different embodiments can be constituted without departing from the essence and scope of the present invention, and the present invention is intended to be Petition 870220063643, dated 07 / 19 / 2022, pages 102 / 108 83 / 83 restricted not by the specific modalities described above, but only by the definitions given in the claims. (Explanation of Reference Numbers) Foamed paper laminate (container body member) 10A Foamed Paper Container 10a Surface of the outer wall of the container 10b Inner wall surface of the container Bottom plate element High Mp resin film (thermoplastic resin layer (A)) Paper substrate Low MP resin film after foaming (foamed thermoplastic resin layer (B), foamed layer (B)) Printed layer 50th layer of sublayer 50b Print Standard Petition 870220063643, dated 07 / 19 / 2022, pages 103 / 108

Claims

1 / 3 CLAIMS 1. Foamed paper laminate, characterized in that it comprises: a foamed paper with a thermoplastic resin layer (A), a paper substrate and a foamed thermoplastic resin layer (B) in this order; and a printed layer formed on a surface of the foamed thermoplastic resin layer (B) of the foamed paper, wherein the number of foamed cells per unit area of ​​the foamed thermoplastic resin layer (B) is 1,000 cells / 1 cm2 or more and 1,600 cells / 1 cm2 or less, wherein the number of foamed cells per unit area is a value calculated as the number of independent cells (bubbles) per 1 cm2 counting the number of independent cells that are present within an interval demarcated by a given length in the vertical and horizontal directions (XY) on the surface of the foamed layer (B),and the number of independent cells is determined by removing the printed layer from the foamed paper laminate using a solvent to expose the surface of the foamed layer (B) and then observing the surface of the foamed layer (B) using an optical microscope, the printed layer includes a cured product formed by: a binder resin containing a polyurethane resin with an acidity value of 1 mgKOH / g 100 mgKOH / g; and at least one carbodiimide-based curing agent and one isocyanate-based curing agent, and a residual percentage of the printed layer after immersion for 30 minutes in ethanol at 25°C is 50% by mass or more. Petition 870260074079, dated 24 / 07 / 2026, p. 12 / 18 2 / 3, 2. Foamed paper laminate, according to claim 1, characterized in that the binder resin has a tensile strength of 0.1 mPa to 50 mPa at an elongation percentage of 50% to 4,000%.

3. Foamed paper laminate, according to claim 1 or 2, characterized in that the binder resin has a glass transition temperature of 100°C to 0°C.

4. Foamed paper laminate, according to any one of claims 1 to 3, characterized in that the printed layer has a film thickness of 0.5 gm to 5.0 gm.

5. Foamed paper laminate, according to any one of claims 1 to 4, characterized in that the printed layer has a plurality of layers and an outermost layer is a transparent layer.

6. Foamed paper laminate, according to any one of claims 1 to 5, characterized in that the foamed thermoplastic resin layer (B) has a thickness of 500 gm to 950 gm.

7. Foamed paper laminate, according to any one of claims 1 to 6, characterized in that the number of foamed cells per unit area of ​​the foamed thermoplastic resin layer (B) is 1,250 cells / 1 cm2 or more and 1,600 cells / 1 cm2 or less.

8. Foam-lined paper container characterized in that it is provided with foam-lined paper laminate as defined in any one of claims 1 to 7.

9. Method for producing foamed paper laminate, as defined in claim 1, characterized in that it comprises: Petition 870260074079, dated 07 / 24 / 2026, page 13 / 18 3 / 3 preparing the foamed paper material having, in order, the thermoplastic resin layer (A), the paper substrate and a foamed thermoplastic resin layer-forming layer (Bo) having a lower melting point than the thermoplastic resin layer (A), and being foamed by means of heating; preparing an aqueous ink composition containing: a binder resin containing a polyurethane resin with an acid value of 1 mgKOH / g 100 mgKOH / g; water; and at least one carbodiimide-based curing agent, and one isocyanate-based curing agent, prepared as an aqueous ink composition; form the printed layer by applying the aqueous ink composition onto a surface of the foamed thermoplastic resin layer forming the (Bo) layer of foamed paper material;and form the foamed thermoplastic resin layer (B) by heating the foamed paper material with the printing layer and thus causing the foamed thermoplastic resin layer (Bo) of the foamed paper material to form.

10. Method for producing foamed paper laminate, according to claim 9, characterized in that the printed layer has a plurality of layers and an outermost layer is a transparent layer.

11. Method for producing foamed paper laminate, according to any one of claims 8 to 10, characterized in that the foamed thermoplastic resin (Bo) forming layer has a film thickness of 40 µm to 150 µm. Petition 870260074079, dated 07 / 24 / 2026, pp. 14 / 18

Images