Colored aluminum foil for cooking

Abstract

To shorten a time required to bake food by imparting a function of positively shortening a time from stopping to re-operating of a heater in an oven toaster to a colored layer in a colored aluminum foil for cooking.SOLUTION: A colored aluminum foil 10 for cooking comprises a colored layer 12 containing heat-resistant resin and carbon black as a black pigment on one surface of a body 11 comprising an aluminum foil, and a surface roughness (Ra) of the colored layer 12 is constituted to be 30-65 nm. When the surface roughness of the colored layer 12 is prescribed in the range, the surface of the colored layer 12 becomes structurally rough while preventing peeling of the colored layer 12 from the body 11, and an apparent surface area is increased so as to increase a heat quantity to be captured and enhance efficiency of heat absorption. As a result of this, a temperature in an oven toaster easily drops, and a time until re-operation of a heater is shortened so as to prolong an operating time of the heater per unit time.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a colored aluminum foil for cooking food, a package made of the colored aluminum foil for cooking, and a method for producing the same. [Background technology]

[0002] Conventionally, foods such as sweet potatoes have been wrapped in aluminum foil and cooked using a toaster oven or the like. In this case, it is also known to use colored aluminum foil for cooking, as described in Patent Document 1, which is made by laminating a colored layer containing a black pigment such as carbon black on one side of a main body made of aluminum foil that wraps food. In such colored aluminum foil for cooking, the colored layer absorbs heat from oven toasters and the like, making cooking more efficient than with uncolored aluminum foil (plain foil). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2010-280131 Summary of the Invention [Problem to be solved by the invention]

[0004] By the way, typical toaster ovens are equipped with a thermostat to prevent the temperature inside the oven from rising too high to prevent fires and other hazards, and the heater will shut off when the temperature inside the oven reaches a certain level. When the supply of heat from the heater is cut off, the temperature inside the refrigerator drops, and when the temperature drops below a certain level, the heater starts operating again. This cycle of operating and stopping the heater is repeated when cooking food.

[0005] In this case, the time between when the heater is turned off and when it is turned back on is so low that it does not contribute much to cooking food, resulting in lost time and the problem of it taking longer to cook food.

[0006] In the colored aluminum foil for cooking described in Patent Document 1, the colored layer absorbs heat and the heat is transferred to the food through the aluminum foil, which results in the temperature inside the toaster oven dropping more easily, and because the temperature drop is so fast, it can be said that the time until the heater can be restarted is shortened to a certain extent.

[0007] However, Patent Document 1 does not focus on actively shortening the time from when the heater in a toaster oven is stopped to when it is restarted. In other words, beyond providing a colored layer on the aluminum foil, no attempt has been made to shorten the heater's downtime.

[0008] Therefore, the problem to be solved by the present invention is to provide a colored aluminum foil for cooking with a function that actively shortens the time from when the heater in a toaster oven is turned off until it is turned back on, in addition to the heat-absorbing effect resulting from the color of the colored layer, thereby shortening the time required to bake food. [Means for solving the problem]

[0009] In order to solve the above-mentioned problems, the colored aluminum foil for cooking according to the present invention comprises a main body made of aluminum foil and a colored layer containing a heat-resistant resin and carbon black as a black pigment, laminated on at least one side of the main body made of aluminum foil, and the surface roughness (Ra) of the colored layer is 30 to 65 nm.

[0010] As described above, the colored aluminum foil for cooking according to the present invention is configured so that the surface roughness (average roughness Ra) of the colored layer containing carbon black as a black pigment is 30 nm or more, which makes the surface of the colored layer structurally rough and increases the apparent surface area, thereby increasing the amount of heat captured from the heater to the surface of the colored layer (reducing the amount of heat reflected). This increases the heat absorption efficiency of the colored aluminum foil for cooking, allowing heat to be transferred to the food, making it easier to lower the temperature inside the toaster oven, shortening the time it takes for the heater to restart, and lengthening the heater operating time per unit time, thereby shortening the time it takes for food to be cooked.

[0011] Furthermore, as described above, the colored aluminum foil for cooking according to the present invention is configured so that the surface roughness of the colored layer containing carbon black as a black pigment is 65 nm or less, thereby preventing the surface of the colored layer from becoming too structurally rough and causing the colored layer to peel off from the main body made of aluminum foil. Therefore, it is possible to maintain the function of actively shortening the time from when the heater is turned off until it is turned back on, and it is possible to maintain the function of shortening the time it takes to cook food.

[0012] In the colored aluminum foil for cooking according to the present invention, it is preferable to adopt a configuration in which the carbon black accounts for 15 to 70% by weight of the colored layer.

[0013] By setting the carbon black content in the colored layer within the above range, it becomes easier to adjust the surface roughness of the surface of the colored layer to within the above-mentioned predetermined range. If the carbon black content is less than 15% by weight, the proportion of the heat-resistant resin becomes excessive, and the structure of the colored layer becomes too fine, making it difficult to increase the surface roughness. Furthermore, if the carbon black content exceeds 70% by weight, the proportion of heat-resistant resin in the colored layer, which serves to hold the carbon black in place, becomes smaller, and the structure of the colored layer becomes too rough, making the colored layer more likely to peel off from the main body made of aluminum foil.

[0014] In the colored aluminum foil for cooking according to the present invention, it is preferable that the average particle diameter of the carbon black in the colored layer is 10 to 90 nm. Here, the average particle diameter refers to the arithmetic mean diameter determined by observing the cross section of the colored layer with an electron microscope and randomly selecting 100 carbon black particles in the colored layer.

[0015] By setting the average particle size of the carbon black in the colored layer within the above range, it becomes easier to adjust the surface roughness of the surface of the colored layer to within the above-mentioned predetermined range. If the average particle size of carbon black is less than 10 nm, it tends to aggregate and is difficult to use as a pigment. In addition, the particles are too small, making the structure of the colored layer too dense and making it difficult to increase the surface roughness. Furthermore, if the average particle size of the carbon black exceeds 90 nm, the carbon black becomes bulky, making it difficult to increase the carbon black content in the colored layer, resulting in a higher proportion of heat-resistant resin and making it difficult to increase the surface roughness of the colored layer.

[0016] In the colored aluminum foil for cooking according to the present invention, it is preferable that the main body made of the aluminum foil has one glossy side and the other poppy side, and that the colored layer is laminated on the poppy side of the main body.

[0017] By laminating a colored layer on the side of the matte surface of the body made of aluminum foil, which has a larger surface roughness than the glossy surface, the adhesion of the colored layer to the body is improved and the colored layer is prevented from peeling off from the body. Furthermore, by laminating a colored layer on the poppy side, the surface properties of the poppy side, which has a large surface roughness, are reflected, and the surface roughness of the colored layer also becomes relatively large, making it easier to adjust the roughness to within the above-mentioned specified range.

[0018] In the colored aluminum foil for cooking according to the present invention, the colored layer has a colored coating film thickness of 0.5 to 5.0 g / m after drying. 2 It is preferable to adopt a configuration in which the coating amount is .

[0019] By setting the coating amount of the colored layer within the above range, it becomes easier to adjust the surface roughness of the colored layer to within the above-mentioned predetermined range. Application amount: 0.5g / m 2 If the thickness is less than this, it becomes difficult to form a coating film, the colored layer becomes more likely to peel off from the main body, and the colored layer becomes too thin, which may prevent it from achieving a sufficient heat absorption effect. Application amount: 5.0g / m 2 If the thickness exceeds this value, the thickness of the coating film increases, the smoothness of the surface increases, and it becomes difficult to increase the surface roughness of the surface.

[0020] In the colored aluminum foil for cooking according to the present invention, the food to be cooked is sweet potato, and it is preferable that the foil is used for baking sweet potato.

[0021] By using the colored aluminum foil for cooking baked sweet potatoes, it becomes possible to bake sweet potatoes with a high sugar content and rich sweetness in a short time.

[0022] In the colored aluminum foil for cooking according to the present invention, the colored layer is laminated only on one side of the main body made of the aluminum foil, and a configuration can be adopted in which the main body further includes a release coating layer laminated on the other side of the main body made of the aluminum foil.

[0023] When cooking, if the aluminum foil for cooking is used so that food comes into contact with the surface on which the release coating layer is laminated, the release coating layer acts to prevent food from sticking to the colored aluminum foil for cooking.

[0024] In the colored aluminum foil for cooking according to the present invention, it is preferable that the release coating layer is made of one or more selected from the group consisting of wax, silicone resin, acrylic resin, urethane resin, ethyl cellulose resin, and mineral oil.

[0025] By configuring the release coating layer as described above, it is possible to make it resistant to denaturation even by heat during cooking and to make it have good heat resistance.

[0026] In order to solve the above-mentioned problems, the packaging material according to the present invention is made from the colored aluminum foil for cooking.

[0027] By configuring the packaging body as described above, it is possible to reduce the time required for food to be cooked.

[0028] In order to solve the above-mentioned problems, the method for manufacturing colored aluminum foil for cooking according to the invention comprises the steps of preparing the aluminum foil that will become the main body, applying an ink containing the heat-resistant resin and carbon black as a black pigment to at least one side of the aluminum foil, and heating the ink-coated aluminum foil to form a colored layer, and the step of forming the colored layer comprises a preheating step of heating the ink-coated aluminum foil at a first temperature, and then a main heating step of heating the ink-coated aluminum foil at a second temperature that is higher than the first temperature.

[0029] When heating an ink-coated aluminum foil to evaporate the ink solvent and form a colored layer, if the foil is suddenly heated to a high temperature, the solvent will evaporate rapidly, causing unexpected cracks in the coating, making it difficult to adjust the surface roughness of the finished colored layer within the above range. Furthermore, the cracks will make the finished colored layer more likely to peel off from the main body. The heating is divided into two stages, a preheating process and a main heating process. In the preheating process, most of the solvent is evaporated at a low temperature, and in the main heating process, the colored layer is baked at a high temperature, which makes it less likely for film cracks to occur, makes it easier to adjust the surface roughness of the colored layer to within the above range, and prevents the colored layer from peeling off from the main body.

[0030] In the method for producing colored aluminum foil for cooking according to the present invention, it is preferable that the preheating step is performed under conditions of a heating temperature of 50 to 100°C and a heating time of 3 to 9 seconds, and the main heating step is performed under conditions of a heating temperature of 180 to 220°C and a heating time of 0.5 to 5 seconds. Furthermore, it is preferable that the preheating step is performed under conditions of a heating temperature of 60 to 80°C and a heating time of 3 to 5 seconds, and the main heating step is performed under conditions of a heating temperature of 190 to 210°C and a heating time of 0.5 to 2.4 seconds.

[0031] By configuring a drying zone or the like and carrying out the preheating step therein at a low temperature for a relatively long time, it is possible to slowly evaporate most of the solvent so as not to cause film cracking, and by carrying out the main heating step using a heated drum or the like at a higher temperature than the preheating step and for a shorter time than the preheating step but still long enough to dry and harden the heat-resistant resin, the colored layer is baked to form a strong colored layer and deterioration is prevented, making it easier to adjust the surface roughness of the colored layer within the above range and further preventing the colored layer from peeling off from the main body. Note that it is not excluded to carry out the main heating step for a longer time than the preheating step as long as the effects of the present invention are achieved. [Effects of the Invention]

[0032] Since the colored aluminum foil for cooking according to the present invention is configured as described above, the colored layer has the function of actively shortening the time from when the heater in a toaster oven is turned off until it is turned back on again, thereby making it possible to shorten the time required to bake food. [Brief explanation of the drawings]

[0033] [Figure 1] Cross-sectional view of a colored aluminum foil for cooking according to an embodiment [Figure 2] FIG. 1 is a perspective view showing a state in which the colored aluminum foil for cooking according to an embodiment is used; [Figure 3] Cross-sectional view of another embodiment of colored aluminum foil for cooking [Figure 4] Schematic diagram showing the state of use of a colored aluminum foil packaging for cooking according to still another embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0034] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. The embodiment of the colored aluminum foil for cooking 10 shown in Figure 1 comprises a main body 11 made of aluminum foil and a colored layer 12 laminated over the entire surface of one side of the main body 11, and is characterized in that the surface roughness (Ra) of the colored layer 12 is set within a predetermined range. As shown in FIG. 2, the food F such as sweet potato is wrapped around the food with the colored layer 12 facing outward and the main body 11 facing inward (the side in contact with the food), and is then cooked in a toaster oven O or the like.

[0035] Any known aluminum foil can be used as the aluminum foil for the main body 11, and is not particularly limited, but for example, an 8000 series (8011, etc.) aluminum foil can be used. Hard, semi-hard, or soft materials can be used for tempering, but soft materials are preferred because they make it easier to wrap the food F.

[0036] The thickness of the aluminum foil of the main body 11 is not particularly limited, but is preferably about 10 to 30 μm. If the thickness is less than 10 μm, the film is too thin and may tear when wrapping the food F, making it difficult to form a colored layer. If the thickness is more than 30 μm, the film is too thick and difficult to wrap the food F, and when wrapped, a gap is likely to form between the film and the food F, reducing heat transfer efficiency. As will be described later, when the colored aluminum foil 10 for cooking is used to make a colored aluminum foil packaging body 10' for cooking, the thickness of the aluminum foil is not particularly limited, but is preferably 30 μm or more and 250 μm or less, and more preferably 50 μm or more and 150 μm or less. If the thickness is less than 30 μm, when a packaging body 10′ such as a container is formed from the colored aluminum foil for cooking, the strength of the packaging body 10′ may decrease and the packaging body 10′ may be deformed. Also, if the thickness exceeds 250 μm, it may be difficult to form the container.

[0037] The aluminum foil of the main body 11 has one glossy surface (shiny noodle) and the other matte surface (matte surface), similar to those generally available on the market. The surface roughness of the poppy side is greater than that of the glossy side, and the colored layer 12 is formed on the poppy side. The surface roughness (Ra) of the poppy surface is not particularly limited, but is preferably 0.2 μm or more, and more preferably 0.25 μm or more. When the surface roughness is set in this range, the adhesion of the colored layer 12 to the main body 11 is improved, peeling is less likely to occur, and the surface roughness of the surface of the colored layer 12 can be easily adjusted to a predetermined range as described below.

[0038] The colored layer 12 contains a heat-resistant resin and carbon black as a black pigment, and may also contain other ingredients such as a dispersant. The type of heat-resistant resin is not particularly limited, but examples include polyamide-imide resin, acrylic resin, epoxy resin, and polyethersulfone resin. Polyamide-imide resin is preferred in terms of chemical resistance, oil resistance, and abrasion resistance. The content of the heat-resistant resin in the colored layer 12 is not particularly limited, but examples include 30 to 85% by weight. The content of the heat-resistant resin is more preferably 40 to 80% by weight. The method for forming the colored layer 12 is not particularly limited, but it is formed by drying a coating of ink containing a heat-resistant resin and carbon black as a black pigment. The printing method or coating method is not particularly limited, but examples of printing methods include gravure printing, screen printing, and calendar printing, and examples of coating methods include spray coating, brush coating, and roller coating. After printing or applying the ink by these methods, the colored layer 12 is formed by drying the coating. Here, the ink solvent is not particularly limited, but examples include alcohol solvents such as ethanol, alkylamide solvents such as dimethylacetamide, ketone solvents such as methyl ethyl ketone and cyclohexanone, aromatic hydrocarbons such as toluene, pyrrolidone solvents such as N-methyl-2-pyrrolidone, and ether solvents such as diethyl ether and tetrahydrofuran.

[0039] As shown in FIG. 1, the colored layer 12 is adjusted so that the surface roughness (Ra) of its surface 12a, i.e., the surface opposite to the surface in contact with the main body 11, is relatively large, at 30 to 65 nm (note that FIG. 1 is merely a schematic diagram and does not accurately depict the size of the irregularities on the surface 12a). More preferably, the surface roughness (Ra) of the surface 12a of the colored layer 12 is adjusted to 35 to 57 nm, and even more preferably, to 45 to 57 nm. As will be described later, such adjustments are made by appropriately adjusting the content of carbon black as a black pigment, the average particle size, the amount of coating applied, and the drying process of the coating. Since the colored layer 12 is laminated on the poppy side of the main body 11, the surface roughness of the poppy side is reflected, and the colored layer 12 naturally has a large surface roughness. This makes it easy to adjust the surface roughness of the colored layer 12 to fall within the above-mentioned predetermined range. By adjusting the surface roughness of the colored layer 12 to fall within this range, peeling of the colored layer 12 from the main body 11 is prevented while the heat absorption efficiency of the colored layer 12 is increased, and the time from when the heater is turned off to when it is turned back on when cooking food F in the toaster oven O is shortened, thereby improving the heating efficiency of the food F.

[0040] The content of carbon black in the colored layer 12 is not particularly limited, but is preferably 15 to 70% by weight, more preferably 20 to 60% by weight. Carbon black is good at absorbing heat from the toaster oven heater. If the carbon black content is less than 15% by weight, the proportion of the heat-resistant resin becomes excessive, and the structure of the colored layer 12 becomes too fine, making it difficult to increase the surface roughness. Furthermore, if the carbon black content exceeds 70% by weight, the proportion of heat-resistant resin in the colored layer 12, which serves to hold the carbon black in place, becomes small, making the structure of the colored layer 12 too rough and making the colored layer 12 more likely to peel off from the main body made of aluminum foil.

[0041] The average particle size of the carbon black in the colored layer 12 is not particularly limited, but is preferably 10 to 90 nm, more preferably 20 to 50 nm. If the average particle size of carbon black is less than 10 nm, it is prone to aggregation and difficult to use as a pigment. In addition, the particles are too fine, making the structure of the colored layer 12 too dense and making it difficult to increase the surface roughness. Furthermore, if the average particle diameter of the carbon black exceeds 90 nm, the carbon black becomes bulky, making it difficult to increase the carbon black content in the colored layer 12, resulting in a higher proportion of heat-resistant resin and making it difficult to increase the surface roughness of the colored layer 12.

[0042] The thickness of the colored layer 12 is not particularly limited, but the thickness of the coating film after drying is preferably 0.5 to 5.0 g / m 2 The coating amount is preferably 0.7 to 2.5 g / m 2 The coating amount is more preferably 0.7 to 0.9 g / m 2 It is more preferable that the coating amount is 1000 ppm or less. Application amount: 0.5g / m 2 If the thickness is less than this, it becomes difficult to form a coating film, the colored layer 12 becomes more likely to peel off from the main body, and the colored layer 12 becomes too thin, which may result in an insufficient heat absorption effect. Application amount: 5.0g / m 2If the thickness exceeds this value, the thickness of the coating film increases, the smoothness of the surface increases, and it becomes difficult to increase the surface roughness of the colored layer 12.

[0043] The manner of drying treatment of the coating film in the colored layer 12 is not particularly limited, and examples include heat drying and natural drying, but it is preferable to carry out two-stage heat drying. That is, a preferred heating and drying process comprises a preheating process in which the ink-coated body 11 is heated at a first temperature T1, followed by a main heating process in which the ink-coated body 11 is heated at a second temperature T2 that is higher than the first temperature T1. The preheating step is carried out, for example, in a drying booth or drying zone, and the main heating step is carried out, for example, in a heated drum. The heating is divided into two stages, a preheating process and a main heating process, in which most of the solvent is evaporated at a low temperature T1 in the preheating process, and the colored layer 12 is baked at a high temperature T2 in the main heating process, thereby making the film less likely to crack. This makes it easier to adjust the surface roughness of the colored layer 12 within the above range, and prevents the colored layer 12 from peeling off from the main body 11.

[0044] The heating time and heating temperature in the preheating step and main heating step are not particularly limited, but it is preferable that the preheating step is carried out under conditions of a heating temperature T1 of 50 to 90°C and a heating time of 3 to 9 seconds, and that the main heating step is carried out under conditions of a heating temperature T2 of 180 to 220°C and a heating time of 0.5 to 5 seconds. By carrying out the preheating step at a relatively low temperature for a long period of time, it is possible to slowly evaporate most of the solvent so as not to cause film cracking, and by carrying out the main heating step at a higher temperature than the preheating step for a shorter period of time than the preheating step but long enough to dry and harden the heat-resistant resin, it is possible to prevent the colored layer from being burned and degraded. This makes it easier to adjust the surface roughness of the colored layer 12 within the above range, and further prevents the colored layer 12 from peeling off from the main body 11. Note that, as long as the effects of the present invention are achieved, it is not excluded that the heating step may be performed for a longer time than the preheating step.

[0045] FIG. 3 shows another embodiment of the colored aluminum foil 10 for cooking. In this embodiment, a colored layer 12 is provided on one surface of a body 11 made of aluminum foil, and a release coating layer 13 is laminated on the other surface. When in use, food F is cooked by bringing it into contact with the surface on which the release coating layer 13 is laminated. When the colored aluminum foil for cooking use 10 is removed from the food F after cooking, the release coating layer 13 acts to prevent the food F from adhering to the colored aluminum foil for cooking use 10. This helps to maintain the appearance of cooked food and also reduces food waste.

[0046] The release coating layer 13 is not particularly limited as long as it has releasability, but it is preferable that it is heat resistant and not easily altered by the heat during cooking. Examples include waxes (plant waxes, animal waxes, mineral waxes, petroleum waxes, synthetic waxes, etc.), silicone resins, fluorine-based resins, acrylic resins, urethane resins, ethyl cellulose resins, mineral oils, and combinations thereof. The method for forming the release coating layer 13 is not particularly limited, and it can be formed on the surface of the main body 11 opposite to the colored layer 12 by a method such as coating or extrusion. The coating amount of the release coating layer 13 is not particularly limited, but is preferably 0.01 g / m 2 ~2.5g / m 2 is preferred, and 0.02 g / m 2 ~1.0g / m 2 The coating amount is more preferably 0.01 g / m 2 If the density is less than 2.5 g / m, it becomes difficult to stably form the release coating layer 13. 2 If it exceeds this value, the film thickness becomes too thick, resulting in high costs.

[0047] FIG. 4 shows a packaging body 10' made of colored aluminum foil for cooking according to the embodiment shown in FIG. The type of the colored aluminum foil packaging 10' for cooking is not particularly limited as long as it can accommodate the food F. That is, it may be a sheet body on which food F can be placed as shown in Fig. 4(a) or which can wrap food F in a bag-like shape as shown in Fig. 4(b), or it may be formed into a container shape capable of containing food F as shown in Fig. 4(c). In this embodiment, a colored layer 12 is provided on one surface of the main body 11, and a release coating layer 13 is laminated on the other surface.

[0048] 4(a) and (b), when the colored aluminum foil packaging 10' for cooking is simply in a sheet form, it may be used as is by placing the food F on the release coating layer 13 side in the unfolded sheet form as shown in FIG. 4(a) ("packaging" as used in this specification includes placing), or it may be used by placing the food F in the center of the sheet with the release coating layer 13 side facing inward and wrapping it in a bag form as shown in FIG. 4(b). When wrapping the food F in a bag form, the colored aluminum foil packaging 10' for cooking may be large enough to allow this.

[0049] Furthermore, as shown in Figure 4(c), when the colored aluminum foil packaging body 10' for cooking is in the shape of a container, it may be prepared by first forming a colored layer 12 in the required areas of the colored aluminum foil 10 for cooking and then press-molding it into the shape of a container, or by press-molding a plain metal foil that does not have a colored layer 12 formed thereon into the shape of a container and then forming the colored layer 12 in the required areas. Here, the shape of the container as the colored aluminum foil packaging 10' for cooking, as shown in Figure 4(c), is not particularly limited, and examples include a bag shape, a quadrilateral shape such as a triangle, square, or rectangle when viewed from above, a polygonal shape such as a circle (including an oval), etc. However, as shown in FIG. 4(c), it is preferable to have at least a bottom wall 14 and a peripheral wall 15 rising from the bottom wall 14, and in some cases a flange 16. If necessary, the bottom wall 14 and the peripheral wall 15 of the container may be formed with unevenness, ribs, or edging. [Example]

[0050] The present invention will be further clarified below by showing examples and comparative examples of the present invention.

[0051] First, Examples 1 to 15 were prepared. In each Example, an aluminum foil (8011 material, thickness 12 μm) was used as the main body of the colored aluminum foil for cooking, and ink was applied to the blank side and dried by heating to form a colored layer.

[0052] The ink used here contained a polyamideimide resin solution (Vylomax manufactured by Toyobo Co., Ltd.; Vylomax is a registered trademark) containing 15% by weight of polyamideimide resin as a heat-resistant resin in solid content and 85% by weight of N-methyl-2-pyrrolidone (NMP), as well as carbon black (CB) as a black pigment. Tetrahydrofuran (THF), N-methyl-2-pyrrolidone (NMP), and cyclohexanone were used as ink diluents to adjust the viscosity during application. The coating amount of the colored layer is 0.7 to 0.9 g / m 2 It was. The heating and drying was carried out in two stages: a preheating process in the drying zone at a heating temperature of 60-80°C for a heating time of 3.6 seconds, and a main heating process in the heated drum at a heating temperature of 200°C for a heating time of 0.9 seconds. The average particle size, content, and surface roughness of the carbon black in the colored layer in each example are shown in Table 1. The average particle size refers to the arithmetic mean diameter determined by observing the cross section of the colored layer with an electron microscope and randomly selecting 100 carbon black particles in the colored layer. The surface roughness refers to the average roughness (Ra) obtained by tapping mode measurement using an Oxford Instruments MFP-3D-SA atomic force microscope (AFM) with an AC160TS probe (spring constant equivalent to 3 N / m) in an air atmosphere at room temperature (25°C). After drying, the colored layer was composed almost entirely of polyamideimide resin, except for the carbon black.

[0053] [Table 1]

[0054] Furthermore, as Comparative Example 1, an aluminum foil (8011 material, thickness 12 μm) similar to that in the example was prepared without a colored layer. Furthermore, in Comparative Examples 2 to 5, the same aluminum foil (8011 material, thickness 12 μm) as in the Examples was used, and ink was applied to the blank side thereof and dried by heating to form a colored layer. The ink used here contained a polyamideimide resin solution (Vylomax manufactured by Toyobo Co., Ltd.; Vylomax is a registered trademark) containing 15% by weight of polyamideimide resin as a heat-resistant resin in solid content and 85% by weight of N-methyl-2-pyrrolidone (NMP), as well as carbon black as a black pigment. Tetrahydrofuran (THF), N-methyl-2-pyrrolidone (NMP), and cyclohexanone were used as ink diluents to adjust the viscosity during application. The coating amount of the colored layer is 0.7 to 0.9 g / m 2 It was. The heat drying was carried out in a heated drum at a heating temperature of 180° C. for a heating time of 30 seconds. The average particle size, content, and surface roughness of the carbon black in the colored layers in Comparative Examples 2 to 5 were as shown in Table 2 below (the meanings of the average particle size and surface roughness are the same as in the Examples). After drying, the colored layers were almost entirely made of polyamideimide resin, except for the carbon black.

[0055] [Table 2]

[0056] Using these samples of the Example and Comparative Examples, an experiment was conducted to bake sweet potatoes using a toaster oven. The toaster oven used was the ET-UB22 manufactured by Zojirushi Corporation, and several sweet potatoes were prepared with roughly the same dimensions and weight, each measuring approximately 15 cm in length, 4 cm in cross-sectional diameter, and 90 g in weight. The toaster oven was set to 1000W, and the dial was kept turned so that it would not turn off, ignoring any differences in start-up time and keeping it running at all times. Since the heater's ON / OFF cycle stabilized after four cycles, the sweet potatoes in the examples and comparative examples were wrapped in a spindle shape so that there were few gaps, and placed in the center of the heating grid inside the oven when the heater turned off.The sweet potatoes were cooked for the time it took for the heater to cycle ON / OFF seven times, and the finished baked sweet potatoes were observed. The results are shown in Table 3 below. In Table 3, ◯ means that the bamboo skewer can be inserted smoothly into the baked sweet potato, △ means that there is a little resistance when the bamboo skewer is inserted into the baked sweet potato but there is no problem in eating it, and × means that there is a lot of resistance when the bamboo skewer is inserted into the baked sweet potato and it is not cooked properly, and ◯ and △ meet the pass criteria. From Table 3, it was confirmed that in all the samples of the Examples, the baked sweet potatoes were baked to a degree that was at least acceptable for eating.

[0057] [Table 3]

[0058] Next, the colored layer was subjected to a rub fastness test using the specimens of the examples and comparative examples. The rubbing fastness test was conducted in accordance with JIS L 0849, Testing Method for Color Fastness to Rubbing, using a Type II rubbing tester, rubbing the surface of the colored layer of each specimen back and forth 100 times, and checking whether the colored layer peeled off and the surface of the aluminum foil was visible. The friction body was a dry white cotton cloth, and in order to prevent uneven friction, this cotton white cloth was doubled and fixed to the testing machine, and the specimen was attached thereon. The results are shown in Table 4 below. In Table 4, ◯ means that the colored layer is not peeled and the surface of the aluminum foil is not visible, △ means that the colored layer has slight peeling of less than 10% of the surface area, and × means that the colored layer has peeled of more than 10% of the surface area, and ◯ or △ is considered to meet the pass criteria. As shown in Table 4, it was confirmed that in all of the specimens of the Examples, no peeling occurred in the colored layer that would interfere with use.

[0059] [Table 4]

[0060] As can be seen from Tables 3 and 4, the results of at least one of the baking confirmation test or the friction fastness test for all the specimens in the comparative examples were marked "X," whereas the results of the baking confirmation test and the friction fastness test for all the specimens in the examples were marked "O" or "△," confirming that both prevention of peeling of the colored layer and shortening of the baking time were achieved. Among the Examples, Examples 3 to 5, Examples 8 and 9, and Examples 11 and 12 were found to have good results in both the bake confirmation test and the rub fastness test.

[0061] Next, using the specimens of Examples 1 and 5 and Comparative Example 1, a verification experiment was conducted on the ON / OFF cycle of the heater attached to the toaster oven. Using the same toaster oven and sweet potatoes as in the sweet potato baking experiment above, The heating power was set to 1000W, and after four cycles during which the heater's ON / OFF cycle stabilized, the sweet potatoes in the specimens of Examples 1 and 5 and Comparative Example 1 were wrapped so that there were few gaps, and placed in the center of the heating grid inside the oven when the heater was turned off. The heater was then turned on / off seven times, the rest time and the operating time of the heater were measured, and the average value of the second to seventh on / off cycles was calculated. The results are shown in Tables 5 to 7. Table 5 shows the results of Example 1, Table 6 shows the results of Example 5, and Table 7 shows the results of Comparative Example 1, respectively. As can be seen from each table, the heater was idle for a shorter period of time in the specimens of the examples than in the specimens of the comparative examples, and as a result, it was confirmed that the time from when the heater was idle until it was restarted was shortened.

[0062] [Table 5]

[0063] [Table 6]

[0064] [Table 7]

[0065] Furthermore, on the surface (glossy surface) on which the colored layer was not formed of each of the specimens of Examples 1, 3, and 9, a silicone resin (a mixture of addition reaction type silicone (trade name: SD7333, manufactured by Dow Corning Toray Co., Ltd.) and a catalyst (trade name: SRX212, manufactured by Dow Corning Toray Co., Ltd.)) was applied in an amount of 0.05 g / m. 2 ) was applied to the substrate and dried to form a release coating layer, thereby preparing Examples 16, 17, and 18, respectively. Similarly, on the surfaces (glossy surfaces) of the specimens of Comparative Examples 2 and 3 on which no colored layer was formed, a silicone resin (a mixture of addition reaction type silicone (trade name: SD7333, manufactured by Dow Corning Toray Co., Ltd.) and a catalyst (trade name: SRX212, manufactured by Dow Corning Toray Co., Ltd.)) was applied in an amount of 0.05 g / m. 2 ) was applied and dried to form a release coating layer, and Comparative Examples 7 and 8 were prepared in this order. Furthermore, as Comparative Example 6, a specimen similar to Comparative Example 1 was prepared, i.e., one in which a release coating layer was not formed on the side on which the colored layer was not formed, and as a reference example, a specimen similar to Example 3 was prepared, i.e., one in which a release coating layer was not formed on the side on which the colored layer was not formed (glossy side).

[0066] Using the samples of the Examples, Comparative Examples, and Reference Examples, an experiment was conducted to bake mochi using a toaster oven. The toaster oven used was an ET-UB22 manufactured by Zojirushi Corporation, and the rice cake used was one square rice cake (50g) manufactured by Sato Foods Co., Ltd. under the trade name "Crispy Slit." The specimens of Examples 16 to 18, Comparative Examples 6 to 8, and Reference Example were cut to a size that could fit inside the oven toaster, and each specimen was spread out into a sheet and placed on the tray of the toaster oven with the side without the colored layer (the glossy side) facing upwards. Then, rice cakes were placed on the sheet and heated for 3 minutes with the toaster oven power set to 1000 W. The appearance of the cooked rice cakes after heating and the state of the rice cakes when they were split in half were observed. The results are shown in Table 8 below. In Table 8, ◎ indicates that most of the mochi has browned and the inside is soft and edible, ○ indicates that less than half of the mochi has browned and the inside is soft and edible, and × indicates that the mochi has not browned and the inside is hard and edible.

[0067] Similarly, the test for peelability of rice cake was carried out using the specimens of the Examples, Comparative Examples and Reference Examples. After heating as described above, the rice cake was picked up with chopsticks and pulled up, and the peelability between the rice cake and the sample was observed. The results are shown in Table 8 below. In Table 8, ◯ indicates that the rice cake has detached from the specimen, and × indicates that the rice cake has not detached from the specimen and the specimen has stuck to it.

[0068] Furthermore, using specimens from these Examples, Comparative Examples, and Reference Examples, a friction fastness test was conducted on the specimens before heating in the same manner as in Examples 1 to 15 and Comparative Examples 1 to 5, and the specimens were similarly evaluated. The results are shown in Table 8 below.

[0069] [Table 8]

[0070] As can be seen from Table 8, the results of at least one of the baking confirmation test, peelability test, and rub fastness test were marked × for all the specimens in the comparative examples, whereas the results of the baking confirmation test, peelability test, and rub fastness test were marked ◎ or ◯ for all the specimens in the examples, confirming that the requirements for preventing peeling of the colored layer, improving peelability, and shortening the baking time were all met.

[0071] The embodiments and examples disclosed herein are illustrative in all respects and are not restrictive. The scope of the present invention is defined by the claims, and includes all modifications and variations within the scope of the claims and their equivalents.

[0072] For example, in the embodiments and examples, the colored layer 12 is formed on only one side of the main body 11 of the colored aluminum foil for cooking 10, but the colored layer 12 may also be formed on both sides of the main body 11. In addition, in the embodiment and example, the colored layer 12 is formed on the poppy surface of the main body 11, but the colored layer 12 can also be formed on the glossy surface. In the embodiments and examples, a colored layer 12 is formed on the entire surface of one side of the main body 11 of the colored aluminum foil 10 for cooking, but the colored layer 12 may have a non-colored area of ​​a few percent in area ratio, such as a trademark or pattern display. In the embodiment and examples, sweet potato is given as an example of the food F that is wrapped in the colored aluminum foil for cooking 10 and cooked, but the type of food F is not limited to this. In the embodiment and examples, a toaster oven O is exemplified as an appliance for heating and cooking food F, but the appliance is not limited to this and may be an oven range or the like. In the embodiments and examples, the drying process for the coating film in the colored layer 12 is carried out by two-stage heating and drying, but as long as the surface roughness of the colored layer 12 can be adjusted to 30 to 65 nm, it is also possible to use a single heating and drying process or a multi-stage heating and drying process with three or more stages. [Explanation of symbols]

[0073] 10. Colored aluminum foil for cooking 10" Colored Aluminum Foil Cookware Packaging 11 Main unit 12 Colored layer 12a Surface of the colored layer 13 Release coating layer 14 Bottom wall 15 Peripheral wall 16 flange F Food O Toaster oven

Claims

1. A colored aluminum foil for cooking that is used to wrap or package food and cook it in a toaster oven or the like, A main body made of aluminum foil; a colored layer containing a heat-resistant resin and carbon black as a black pigment, laminated on at least one surface of the body made of aluminum foil; The surface roughness (Ra) of the colored layer is 45 to 57 nm, The carbon black accounts for 40 to 70% by weight of the colored layer, A colored aluminum foil for cooking in which the colored layer surface is rubbed back and forth 100 times using a Type II friction tester in accordance with JIS L 0849, a test method for color fastness to friction, and the colored layer does not peel off and the surface of the aluminum foil is not visible.

2. A colored aluminum foil for cooking that is used to wrap or package food and cook it in a toaster oven or the like, A main body made of aluminum foil; a colored layer containing a heat-resistant resin and carbon black as a black pigment, laminated on at least one surface of the body made of aluminum foil; The surface roughness (Ra) of the colored layer is 45 to 57 nm, The colored aluminum foil for cooking, wherein the carbon black has an average particle size of 21 to 50 nm.

3. In the colored layer, 3. The colored aluminum foil for cooking according to claim 2, wherein the carbon black accounts for 40 to 70% by weight.

4. In the colored layer, 2. The colored aluminum foil for cooking according to claim 1, wherein the carbon black has an average particle size of 21 to 50 nm.

5. The aluminum foil body has one glossy surface and the other matte surface, 5. The colored aluminum foil for cooking according to claim 1, wherein the colored layer is laminated on the poppy side of the main body.

6. The colored layer has a colored coating film thickness of 0.5 to 5.0 g / m after drying. ２ The colored aluminum foil for cooking according to any one of claims 1 to 5, wherein the coating amount is

7. The food product is a sweet potato. The colored aluminum foil for cooking according to any one of claims 1 to 6.

8. The colored layer is laminated on only one surface of the main body made of aluminum foil, The colored aluminum foil for cooking according to any one of claims 1 to 7, further comprising a release coating layer laminated on the other surface of the aluminum foil body.

9. The colored aluminum foil for cooking according to claim 8, wherein the release coating layer is made of one or more selected from the group consisting of wax, silicone resin, acrylic resin, urethane resin, ethyl cellulose resin, and mineral oil.

10. A packaging body made of colored aluminum foil for cooking, which is made of the colored aluminum foil for cooking described in any one of claims 1 to 9.

11. A method for producing a colored aluminum foil for cooking according to any one of claims 1 to 9, A step of preparing an aluminum foil that becomes the main body; A step of applying an ink containing the heat-resistant resin and carbon black as a black pigment to at least one surface of the aluminum foil; and a step of heating the aluminum foil on which the ink has been applied to form a colored layer, The step of forming the colored layer includes: a preheating step of heating the ink-coated aluminum foil at a first temperature; A method for producing colored aluminum foil for cooking, comprising: a main heating step of heating the aluminum foil on which the ink has been applied at a second temperature higher than the first temperature.

12. The preheating step includes: The heating temperature is 50 to 100°C and the heating time is 3 to 9 seconds. The main heating step includes: The method for producing colored aluminum foil for cooking according to claim 11, wherein the heating is carried out under conditions of a heating temperature of 180 to 220°C and a heating time of 0.5 to 5 seconds.

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