cap

Abstract

A cap having a disc-shaped top plate and a tube-shaped skirt portion installed on the periphery edge of the top plate, wherein the top plate comprises a substrate and a resin film installed on the inner cap side of the substrate, and the resin film comprises a polyester resin and a lubricant, and a cap body having a sealing member installed within the cap body opposite the top plate and having an outer diameter smaller than the inner diameter of the skirt portion, wherein the top plate comprises a substrate and a resin film installed on the inner cap side of the substrate, and the resin film comprises a cap body having a sealing member that is separate from the cap body and is installed within the cap body opposite the top plate, and has an outer diameter smaller than the inner diameter of the skirt portion.

Description

Technology Field

[0001] The present invention relates to a cap for sealing a can container. Background Technology

[0002] Conventionally, paints containing epoxy-based resins, such as epoxyphenol resin, as the main component have been widely used as inner surface coatings for metal caps that seal the opening of can containers (see, for example, Patent Documents 1 and 2). Meanwhile, in order to reduce the opening torque when opening the cap, a cap is known that comprises a metal cap body and a resin sealing member installed separately within the cap body (see, for example, Patent Documents 3 and 4). Prior art literature

[0003] Japanese Patent Publication No. 2009-208795, Japanese Patent No. 6534377, Japanese Patent Publication No. 2004-217295, Japanese Patent Publication No. 2017-178421 The problem to be solved

[0004] In the caps described in Patent Documents 3 and 4, it is believed that friction between the inner surface of the top plate of the cap body and the sealing member has a significant effect on the cap opening performance. Therefore, the inventors tested reducing said friction by adding a lubricant to the inner surface coating of the cap body. Specifically, when the inventors added a lubricant to a coating made of epoxyphenol resin as the inner surface coating of the cap body, they encountered a problem in which the friction-reducing effect of the lubricant was not exhibited, and thus the cap opening torque could not be sufficiently reduced (see Example 8 of the [Examples] described below).

[0005] Therefore, the present invention aims to solve the above problem and provide a cap with excellent cap opening properties. means of solving the problem

[0006] The inventors have newly discovered that when a lubricant is added to a paint made of a polyester resin, the friction-reducing effect of the lubricant is exhibited, thereby reducing the opening torque of a cap, and thus have completed the present invention.

[0007] That is, according to the present invention,

[0008] A cap body having a disc-shaped top plate and a tube-shaped skirt portion installed on the periphery edge of the top plate, wherein the top plate comprises a substrate and a resin film installed on the inner surface of the cap of the substrate, and wherein the resin film comprises a polyester resin and a lubricant.

[0009] A sealing member installed separately from the above-mentioned cap body, facing the top plate portion, and having an outer diameter smaller than the inner diameter of the skirt portion.

[0010] A cap equipped with is provided. Effects of the invention

[0011] According to the present invention, a cap with excellent cap opening properties is provided. Brief explanation of the drawing

[0012] FIG. 1 is a side view showing the configuration of the opening portion of a cap and a can container according to one embodiment of the present invention in a partial cross-sectional view. Figure 2 is a side view showing the configuration of the above-mentioned cap in a partial cross-section. Figure 3 is a cross-sectional view showing the configuration of the above-mentioned cap. Figure 4 is a cross-sectional view showing the configuration of the above-mentioned cap. Figure 5 is a flowchart illustrating the method of manufacturing the above-mentioned cap. Figure 6 is a flowchart schematically illustrating a part of the method for manufacturing the above-mentioned cap. Specific details for implementing the invention

[0013] Hereinafter, a cap (1) according to one embodiment of the present invention will be described using FIGS. 1 to 4. The following description is intended to explain the present invention in detail and is not intended to limit the present invention.

[0014] FIG. 1 is a side view showing a partial cross-sectional view of the configuration of the opening portion of a cap and a can container according to one embodiment of the present invention. FIG. 2 is a side view showing a partial cross-sectional view of the configuration of the cap (1). FIG. 3 is a cross-sectional view showing the configuration of the cap (1) before it is wound and fixed to the can container (100). FIG. 4 is a cross-sectional view showing the configuration of the cap (1) after it is wound and fixed to the can container (100).

[0015] As shown in FIG. 1, the cap (1) is attached to the opening (110) of the can container (100) and seals the can container (100) by being fixed by drawing molding while placed over the opening (110) of the can container (100). By sealing the can container (100), the cap (1) forms a bottle-shaped can in which a liquid, such as a beverage, is sealed and filled together with the can container (100).

[0016] Here, the can container (100) is a so-called bottle-type container for holding beverages, etc. For example, the can container (100) is made of a metal material such as an aluminum alloy or a surface-treated steel plate with resin films laminated on both sides. The can container (100) is formed in a cylindrical shape having a different outer diameter with one end having a reduced diameter. The can container (100) has an inlet (110) at one end for discharging the contained beverage. The inlet (110) has a jaw (111), a male screw (112), and a curl (113) on its outer surface, extending from the bottom surface side of the can container (100) toward the end.

[0017] The jaw portion (111) is formed by protruding in a ring shape. The curl portion (113) is formed with a smaller diameter than the male screw portion (112). Also, the curl portion (113) is formed to be smaller than the inner diameter of the cap (1). The curl portion (113) is formed by the end of the inlet portion (110) being folded one or more times. The curl portion (113) forms an opening for discharging the beverage stored in the can container (100).

[0018] As shown in FIGS. 1 to 4, the cap (1) has a cap body (11) and a sealing member (12) installed separately within the cap body (11).

[0019] The cap body (11) is composed of a material in which a resin film is formed on a metal material such as an aluminum alloy. In this embodiment, a specific resin film is provided on the inner surface of the cap body (11). This resin film will be described in detail later. The cap body (11) is formed by drawing the material, which is in the shape of a thin flat plate, into a cup shape, and then performing various forming processes such as knurling and roll-on forming.

[0020] The cap body (11) is equipped with a disc-shaped top plate (21) and a cylindrical skirt portion (22) integrally installed on the periphery edge of the top plate (21). The cap body (11) is formed such that the top plate (21) and the skirt portion (22) are integrally and continuously connected by a toroidal and curved corner portion (23).

[0021] The top plate (21) is configured in the shape of a disc, and its main surface is configured as a flat plane. The skirt portion (22) is configured such that one end is continuous with the top plate (21) through a corner portion (23), and the other end is open. The skirt portion (22) is equipped with a plurality of flat portions (31) having a vent slit (31a), a plurality of concave portions (32), a female screw portion (33), and a tamper evidence band portion (34) from the end on the side of the top plate (21) to the end that is open.

[0022] The top plate portion (21) comprises a substrate and a resin film (hereinafter also referred to as an inner resin film) installed on the inner side of the cap of the substrate, and the inner resin film comprises a polyester resin and a lubricant. Specifically, the inner resin film comprises a polyester resin as the main component and a lubricant as an additive. The inner resin film may additionally include additives other than a lubricant as needed. The resin film can be formed on the substrate by a known method, for example, baking. In addition, the top plate portion (21) may be equipped with a known resin film, such as epoxyphenol resin or polyester resin, on the outer side of the cap of the substrate. Additionally, printing may be performed on the outer side of the cap of the substrate.

[0023] As described above, the substrate is typically a metal substrate such as an aluminum alloy.

[0024] The polyester resin used to form the inner resin film may be any polyester resin commonly used to form the resin film of bottle-type cans, and is commercially available. Polyester resin refers to a resin composed of polyester.

[0025] The inner resin film comprises a lubricant in addition to the polyester resin. The lubricant preferably comprises a hydrocarbon wax. Since the hydrocarbon wax exists dispersed in the form of solid particles within the resin film, it may be referred to as a "dispersed wax" or "particulate wax." The hydrocarbon wax is preferably polyethylene wax. The hydrocarbon wax is added to the polyester resin in an amount of, for example, about 2 mass% to about 7 mass%, preferably about 3 mass% to about 7 mass%. By using a hydrocarbon wax as a lubricant, the opening torque of the cap (1) can be significantly reduced, thereby significantly improving the opening ability of the cap (1).

[0026] The mechanism by which hydrocarbon wax can exhibit a remarkably superior effect is examined below. Hydrocarbon wax has a high melting point, so it is thought that it remains dispersed in the form of solid particles within the resin film even when heated during cap manufacturing. For this reason, hydrocarbon wax can form irregularities on the surface of the inner resin film, which is mainly composed of polyester resin. It is thought that these irregularities make the contact between the inner resin film and the can container (100) a point contact rather than a surface contact, thereby improving the sliding between the inner resin film and the can container (100). Furthermore, because the crosslinking density of the polyester resin is low, it is thought that during cap molding, the polyester resin follows the solid particles of the hydrocarbon wax flexibly, allowing the solid particles of the hydrocarbon wax to be stably maintained without falling off the surface of the resin film.

[0027] Meanwhile, when an inner resin film is formed by adding a hydrocarbon wax to an epoxyphenol resin, the flexibility of the epoxyphenol resin is low because the crosslinking density of the epoxyphenol resin is higher compared to that of a polyester resin. In particular, it is difficult to stably maintain the solid particles of the hydrocarbon wax on the surface of the resin film during cap molding, and it is thought that the solid particles of the hydrocarbon wax are prone to detaching from the surface of the resin film.

[0028] When using a hydrocarbon wax as a lubricant, the hydrocarbon wax may be used alone or in combination with other lubricants. Fatty acid ester wax may be used as another lubricant. Since fatty acid ester wax exists in either a molten or solidified state depending on the temperature in the resin film, it may be called a "molten wax." The fatty acid ester wax is preferably lanolin. The fatty acid ester wax is added to the polyester resin in an amount of, for example, about 2 mass% to about 7 mass%, preferably about 3 mass% to about 7 mass%. When a hydrocarbon wax is used in combination with a fatty acid ester wax as a lubricant, compared to when the hydrocarbon wax is used alone, the 2nd torque (i.e., the torque at the time of breakage of the breakage portion (34a) of the tamper evidence band portion (34) of the cap described later) is further reduced, and the cap opening ability can be further improved. Fatty acid ester-based waxes are easy to exist in a molten state and have the effect of lowering the coefficient of dynamic friction, so by reducing the frictional resistance during the opening operation of the cap, the second torque can be reduced.

[0029] The mechanism by which fatty acid ester wax can exert the above effect through combined use with hydrocarbon wax is examined below. Fatty acid ester wax has a low melting point, for example, 40°C, and can volatilize from the surface of the resin film during heating for cap manufacturing (for example, drying in an oven when printing on the outer surface of the cap). Even if fatty acid ester wax volatilizes from the surface of the resin film, it is thought that because the crosslinking density of the polyester resin constituting the resin film is low, the fatty acid ester wax present inside the resin film seeps out to the surface, thereby improving the sliding between the inner resin film and the can container (100) when the cap is opened. In addition, it is thought that fatty acid ester wax contributes to the dispersion of solid particles of hydrocarbon wax in the resin film, and also contributes to preventing solid particles of hydrocarbon wax from falling off the surface of the resin film during cap molding.

[0030] On the other hand, when an inner resin film is formed by adding a fatty acid ester-based wax to an epoxyphenol resin, it is thought that the fatty acid ester-based wax present inside the resin film cannot exert an effect as a lubricant because the crosslinking density of the epoxyphenol resin is higher compared to that of the polyester resin, making it difficult for the wax to seep out to the surface.

[0031] As shown in FIGS. 1 and 2, a cup-shaped molded product is formed by processing such as knurling or roll-on molding, in which a plurality of knurled portions (31), a plurality of concave portions (32), a female screw portion (33), and a tamper evidence band portion (34) are formed by a top plate portion (21), a cylindrical skirt portion (22) in which the plurality of knurled portions (31), a plurality of concave portions (32), a female screw portion (33), and a tamper evidence band portion (34) are not formed, and a corner portion (23).

[0032] The flat portion (31) has a vent slit (31a) and protrudes from the inner surface of the skirt portion (22). In other words, the flat portion (31) forms a projection that is partially cut off from the inner surface of the skirt portion (22) by causing a part of the skirt portion (22) to be sunk inward from the diameter direction of the skirt portion (22).

[0033] Multiple flat sections (31) are installed in the circumferential direction of the skirt section (22). The vent slit (31a) is a slit that discharges gas, etc., from inside the can container (100) upon opening. The vent slit (31a) is formed by cutting the end of the flat section (31) on the top plate side (21).

[0034] The diameter of the connecting circle that is continuous at the end of the vent slit (31a) side of the plurality of planks (31), in other words, at the end of the top plate (21) side of the plurality of planks (31), is set to be smaller than the outer diameter of the sealing member (12). Because of this, the plurality of planks (31) form a locking part that restricts the movement of the sealing member (12) placed on the top plate (21) in a direction separated from the top plate (21).

[0035] The concave portion (32) is formed by a part of the skirt portion (22) being sunken from the outer surface side to the inner surface side. Specifically, the concave portion (32) is formed by a part of the skirt portion (22) being sunken inward from the diameter direction of the skirt portion (22), thereby forming a protrusion on the inner surface of the skirt portion (22).

[0036] The concave portion (32) has an inclined surface (32a) on the inner side of the skirt portion (22). The inclined surface (32a) is inclined in the direction separated from the top plate portion (21) in the axial direction, and also inward in the diameter direction. In other words, as the concave portion (32) is separated from the top plate portion (21), the height from the inner circumference of the skirt portion (22) increases, and thus the inner surface of the concave portion (32) is inclined.

[0037] The concave portions (32) are installed in multiple numbers, preferably at least three, and in this embodiment, four. For example, the concave portions (32) are arranged along the circumferential direction of the skirt portion (22) at approximately equal intervals. The diameter of the circles connected to the inclined surfaces (32a) of the multiple concave portions (32) is configured to be equal to the outer diameter of the sealing member (12) in at least a portion of the axial direction. In other words, the multiple inclined surfaces (32a) are configured to be able to contact the outer edge of the sealing member (12) in a portion of the axial direction, thereby regulating the movement of the sealing member (12) in the diametrical direction and serving as a regulating portion that determines the position of the sealing member (12) in the diametrical direction. That is, the multiple concave portions (32) center the cap body (11) of the sealing member (12) that is in contact with the inclined surfaces (32a). Additionally, the diameter of the circle that continues at the lowest end in the axial direction of the plurality of inclined surfaces (32a) is set to be larger than the diameter of the circle that continues at the innermost end in the diameter direction of the end of the vent slit (31a) side of the plurality of planks (31).

[0038] Additionally, a plurality of concave portions (32) are positioned such that a portion having a diameter equal to the outer diameter of the sealing member (12) of at least the inclined surface (32a) is positioned toward the top plate portion (21) in the axial direction of the skirt portion (22), rather than the catch portion which is the end of the vent slit (31a) of the plank portion (31). For example, the plurality of concave portions (32) are positioned together with the plurality of plank portions (31) in the circumferential direction of the skirt portion (22), and are positioned toward the top plate portion (21) in the axial direction of the skirt portion (22), rather than the plurality of plank portions (31).

[0039] In this embodiment, a plurality of planks (31) are installed at 13 locations, and a plurality of concave portions (32) are installed at 4 locations. For example, in the circumferential direction of the skirt portion (22), three planks (31) are arranged at three locations, and four planks (31) are arranged at one location, and one concave portion (32) is placed between the rows of each plank (31). Also, in this embodiment, the plurality of concave portions (32) are placed on the top plate portion (21) side rather than the plurality of planks (31) of the skirt portion (22).

[0040] The female screw portion (33) is configured to be screw-coupled with the male screw portion (112) of the can container (100). The female screw portion (33) is formed together with the can container (100). That is, the female screw portion (33) is not formed in the cap (1) before it is attached to the can container (100), but is formed when it is integrally combined with the can container (100).

[0041] The tamper evidence band portion (34) is engaged with the jaw portion (111) of the can container (100) in the direction in which the cap (1) is separated from the can container (100) and also in the axial direction of the cap (1). Additionally, the tamper evidence band portion (34) has a break portion (34a) for breaking and detaching from the skirt portion (22) when the cap (1) is opened. That is, the tamper evidence band portion (34) is configured by forming a slit with the break portion (34a) on the end side of the skirt portion (22), and, similar to the female screw portion (33), when combined integrally with the can container (100), it is formed into the shape of the jaw portion (111) of the can container (100) and is engaged with the jaw portion (111).

[0042] The corner portion (23) is, for example, a ring-shaped part whose cross-sectional shape is curved at one center of curvature before the cap body (11) is wound and fixed to the inlet portion (110) of the can container (100). Then, during the drawing molding process when the cap body (11) is wound and fixed to the inlet portion (110) of the can container (100), a part of the corner portion (23) is pressed in the axial direction in a ring shape along the circumferential direction, so that, for example, it is formed into a ring-shaped part whose cross-sectional shape is curved at at least two centers of curvature.

[0043] The sealing member (12) is composed of a separate body from the cap body (11). That is, the sealing member (12) is positioned opposite the top plate portion (21) and the skirt portion (22), and is not bonded to the cap (1). Specifically, the sealing member (12) is configured in a disc shape and has an outer diameter larger than the diameter of the inscribed circle of the plate portion (31) installed on the skirt portion (22) of the cap body (11). In addition, the sealing member (12) has an outer diameter equal to the diameter of the inscribed circle of the central portion in the axial direction of at least a portion of the inclined surface (32a) of the concave portion (32) protruding in the diameter direction from the inner circumference of the skirt portion (22), as a specific example.

[0044] The sealing member (12) is integrally installed in the cap body (11) by engaging the end portion (31) on which the vent slit (31a) of the flat portion (31) protruding in the radial direction from the inner circumferential surface of the skirt portion (22) in the axial direction of the cap body (11). Additionally, the sealing member (12) is centered so that its center is positioned on the axial line of the cap body (11) by engaging the inclined surface (32a) of the concave portion (32) protruding in the radial direction from the inner circumferential surface of the skirt portion (22) in the radial direction of the cap body (11).

[0045] The sealing member (12) has a disc-shaped sliding layer (41) and a disc-shaped sealing layer (42) integrally laminated to the sliding layer (41). The sealing member (12) is formed by the sliding layer (41) and the sealing layer (42) being integrally molded from different resin materials. The sealing member (12) has a flat plate portion (12a) with a uniform thickness and a curved portion (12b) on the outer edge of the top plate portion (21) that is curved.

[0046] In other words, the sealing member (12) is formed in the shape of a disc, and the corner portion on the top plate (21) side is formed as a curved surface with a predetermined curvature. In addition, the curved portion (12b) constituting the outer edge of the sealing member (12) is formed to be thinner than the flat plate portion (12a), and the thickness of the curved portion (12b) gradually decreases from the center side toward the outer edge, so that the leading edge of the curved portion (12b), that is, the outer edge, is formed to be the thinnest than the other portions.

[0047] The flat portion (12a) forms a sealing portion where a part of the curved portion (12b) side contacts the opening portion (110) of the can container (100). The sealing portion of the flat portion (12a) that contacts the opening portion (110) of the can container (100) is formed to be thicker than other parts.

[0048] The sliding layer (41) is composed of a resin material that is relatively harder (harder) than the sealing layer (42). Additionally, the sliding layer (41) is composed of a resin material that does not have adhesive or tackiness to the inner resin film of the cap body (11). That is, the sliding layer (41) is not adhesive to the top plate (21) and slides the top plate (21) while in contact with the top plate (21).

[0049] The resin material used for the sliding layer (41) may include olefin resins such as polypropylene resin or polyethylene resin, polyester resins such as polyethylene terephthalate, styrene resins, acrylic resins, etc. In this embodiment, the sliding layer (41) is composed of polypropylene resin, for example. In addition, pigments, lubricants, softeners, etc. may be appropriately added to the resin material used for the sliding layer (41).

[0050] As shown in FIGS. 1 to 4, the sliding layer (41) is installed separately from the cap body (11) and faces the top plate portion (21) of the cap body (11). The sliding layer (41) is configured to slide with the top plate portion (21) of the cap body (11) by means of a resin material used. The sliding layer (41) is configured in the shape of a disc. The outer diameter of the sliding layer (41) is smaller than the inner diameter of the skirt portion (22), larger than the inscribed circle of the plurality of flat portions (31), and larger than the outer diameter of the curl portion (113) of the inlet portion (110).

[0051] The sliding layer (41) has a first flat plate portion (41a), a first curved portion (41b) formed by a curved surface on the outer edge of the top plate portion (21), a protrusion portion (41c) installed on the sealing layer (42) side of the first curved portion (41b), and a thin-walled portion (41d) installed on the first flat plate portion (41a). The thickness of the first flat plate portion (41a) from the center of the sliding layer (41) to the outer edge side, which is opposite to the curl portion (113) of the entrance portion (110), is uniformly formed, excluding the thin-walled portion (41d).

[0052] The first curved section (41b) is configured such that the thickness of the portion from the outer edge to the outer edge gradually decreases toward the outer edge, as the top plate portion (21) side is curved, compared to the portion facing the curl portion (113) of the entrance portion (110). Additionally, for example, the portion of the first curved section (41b) adjacent to the first flat plate portion (41a) is set to have the same thickness as the first flat plate portion (41a) and is also thicker than the thin-walled portion (41d).

[0053] The projection (41c) is installed on the opening side of the skirt portion (22) at the outer edge of the first curved portion (41b). The projection (41c) is formed in a curved or inclined annular shape that is inclined toward the opening end side of the skirt portion (22) and inclined with respect to the axial direction of the sliding layer (41) and the plane direction of the top plate portion (21). The thickness of the projection (41c) gradually decreases from the first curved portion (41b) toward the tip.

[0054] The thin-walled portion (41d) is installed on the main surface of the opening side of the skirt portion (22) of the first flat portion (41a). The thin-walled portion (41d) is an annular recessed portion configured such that the main surface of the opening side of the skirt portion (22) is parallel to the main surface of the opening side of the skirt portion (22) of the first flat portion (41a). The thin-walled portion (41d) is continuous with the first flat portion (41a) and the first curved portion (41b) as inclined surfaces (41d1, 41d2) inclined with respect to its main surface.

[0055] That is, the thin-walled portion (41d) is continuous with the portion adjacent to the inner and outer sides in the diameter direction of the thin-walled portion (41d) and the inclined surface (41d1, 41d2), so the portion adjacent to the inner and outer sides in the diameter direction of the thin-walled portion (41d) becomes thicker than the thin-walled portion (41d). In this embodiment, the portion adjacent to the inner and outer sides in the diameter direction of the thin-walled portion (41d) is the portion of the first flat plate portion (41a) excluding the thin-walled portion (41d) and the first curved portion (41b).

[0056] Specifically, the thin-walled portion (41d) connects its main surface and the main surface of the first flat portion (41a) by an annular inclined surface (41d1). Here, if the inclined surface (41d1) can guide the resin material of the sealing layer (42) to the thin-walled portion (41d), the angle of inclination of the inclined surface (41d1) can be appropriately set.

[0057] Additionally, the thin-walled portion (41d) connects its main surface and the main surface of the first curved portion (41b) by an annular inclined surface (41d2). Here, if the inclined surface (41d2) can guide the resin material of the sealing layer (42) to the thin-walled portion (41d), the angle of inclination of the inclined surface (41d2) can be appropriately set.

[0058] The thin-walled portion (41d) is installed on the main side opposite to the top plate portion (21) of the first flat plate portion (41a), that is, on the main side where the sealing layer (42) is laminated. When the sealing member (12) is placed on the cap body (11), the thin-walled portion (41d) is installed at a position opposite to the point of deformation of the top plate portion (21) when the cap (1) is mounted on the can container (100) and the corner portion (23) of the cap body (11) is drawn. Additionally, the thin-walled portion (41d) is installed at a position adjacent in the axial direction to the portion opposite to the inlet portion (110) of the sealing layer (42) when the cap (1) is mounted on the can container (100).

[0059] The diameter-direction width of the thin-walled portion (41d) is formed such that when a sealing member (12) is placed on the cap body (11) and the cap (1) is placed on the opening portion (110) of the can container (100), it is positioned opposite the point of deformation of the top plate portion (21) during drawing molding, and positioned opposite the opening portion (110) in the axial direction. Here, the diameter-direction width of the thin-walled portion (41d) is appropriately set by taking into account the difference between the inner diameter of the cap body (11) and the outer diameter of the sealing member (12), the shrinkage rate of the resin material constituting the sliding layer (41) and the sealing layer (42) of the sealing member (12), the amount of deformation caused by external force on the sliding layer (41), and dimensional accuracy.

[0060] The sealing layer (42) is composed of a resin material that is relatively less hard (softer) than the sliding layer (41). Examples of resin materials used for the sealing layer (42) include olefin resin, polyester resin, styrene resin, acrylic resin, etc., and more suitably, examples include a blend of styrene elastomer and polypropylene resin, a blend of low-density polyethylene and styrene elastomer, polyester elastomer, etc. In this embodiment, the sealing layer (42) is composed of, for example, a mixed material of styrene elastomer and polypropylene resin. In addition, pigments, lubricants, softeners, etc. may be appropriately added to the resin material used for the sealing layer (42).

[0061] As shown in FIGS. 1 to 4, the sealing layer (42) is integrally installed on the main surface of the sliding layer (41) on the side facing the inlet portion (110). The sealing layer (42) is configured in the shape of a disc. The outer diameter of the sealing layer (42) is configured to be larger than the outer diameter of the curl portion (113) of the inlet portion (110), and is configured to be approximately the same as the outer diameter of the sliding layer (41).

[0062] As shown in FIG. 3, the sealing layer (42) has a second flat section (42a) in which the thickness of the portion facing the inlet portion (110) is thicker than other portions, a second curved section (42b) in which the outer surface of the outer edge of the top plate portion (21) side is curved, an annular recess (42c) installed on the main surface opposite to the sliding layer (41) side of the second curved section (42b), and a thick section (42d) installed on the second flat section (42a). The main surface of the second flat section (42a) facing the curl portion (113) is formed as a flat surface. For example, the second flat section (42a) is formed with the same diameter as the first flat section (41a) of the sliding layer (41). The second flat section (42a) together with the first flat section (41a) constitutes the flat section (12a) of the sealing member (12).

[0063] The second curved portion (42b) has a main surface that is flush with the main surface facing the curl portion (113) of the second flat portion (42a), for example. The second curved portion (42b) is configured such that the thickness of the portion from the outer edge to the outer edge of the second curved portion (42b) gradually decreases toward the outer edge of the second curved portion (42b) compared to the portion facing the curl portion (113) of the inlet portion (110). The second curved portion (42b) is laminated on the first curved portion (41b) and the protrusion portion (41c). The second curved portion (42b) together with the first curved portion (41b) and the protrusion portion (41c) constitutes the curved portion (12b) of the sealing member (12).

[0064] The recess (42c) is, for example, an annular recess with a semicircular cross-section. When the sealing member (12) is placed on the cap body (11), the recess (42c) comes into contact with, for example, the end on the vent slit (31a) side of the plate (31).

[0065] The thick section (42d) is an annular projection (42d1, 42d2) protruding from both sides of the second flat section (42a). The annular first projection (42d1) protruding from the side of the sliding layer (41) of the second flat section (42a) of the thick section (42d) is positioned in the thick section (42d). The annular second projection (42d2) protruding from the side opposite to the sliding layer (41) of the second flat section (42a) of the thick section (42d) covers the first projection (42d1) in the axial direction and has a wider width than the first projection (42d1) in the diameter direction.

[0066] The thick portion (42d), together with the thin portion (41d), forms a sealing portion that contacts the opening portion (110) of the can container (100). The thickness of the thick portion (42d) is set such that the difference between its own thickness and the thickness of the second flat portion (42a) is greater than the depth from the first flat portion (41a) of the thin portion (41d). That is, the thickness of the first protrusion (42d1) is set to be equal to the depth of the thin portion (41d), and by making the thick portion (42d) additionally have a second protrusion (42d2), the sealing portion that contacts the opening portion (110) of the flat portion (12a) of the sealing member (12) is configured to be thicker than other parts of the flat portion (12a).

[0067] Specifically, the diameter width of the first protrusion (42d1) is the same as the width of the thin-walled portion (41d). That is, the diameter width of the first protrusion (42d1) is formed such that when a sealing member (12) is placed on the cap body (11) and the cap (1) is placed on the inlet portion (110) of the can container (100), it is possible to be in a position opposite to the starting point of deformation of the top plate portion (21) during drawing molding, and in a position opposite to the inlet portion (110) in the axial direction. Also, specifically, the diameter width of the second protrusion (42d2) is formed such that when a sealing member (12) is placed on the cap body (11) and the cap (1) is placed on the inlet portion (110) of the can container (100), it is possible to be in a position opposite to the inlet portion (110) in the axial direction.

[0068] In addition, the diameter-direction width of the first protrusion (42d1) and the diameter-direction width of the second protrusion (42d2) are appropriately set by taking into account the difference between the inner diameter of the cap body (11) and the outer diameter of the sealing member (12), the shrinkage rate of the resin material constituting the sliding layer (41) and the sealing layer (42) of the sealing member (12), the amount of deformation caused by external force on the sliding layer (41), and dimensional accuracy.

[0069] The sealing member (12) is positioned with the cap (1) facing upward with the top plate (21) facing upward, and when the sealing member (12) falls downward from the top plate (21), it comes into contact with the end of the vent slit (31a) side of the flat plate (31), thereby being caught by the flat plate (31) and restricting downward movement in the direction of gravity. Additionally, when the cap (1) is placed over the opening (110) of the can container (100), the sealing member (12) has a thick portion (42d) in contact with the opening (110), and a thin portion (41d) is positioned opposite the point where the top plate (21) deforms during the drawing process of the corner portion (23).

[0070] A method for manufacturing a cap (1) configured in this manner will be described below using FIGS. 5 and FIGS. 6. In addition, the female screw portion (33) installed on the cap body (11) is formed when capping the cap (1) to the can container (100). Therefore, as a method for manufacturing a cap (1), a method for manufacturing a bottle-type can is described, which includes mounting the cap (1) to the can container (100) and sealing the can container (100).

[0071] First, for example, a metal plate material having the inner resin film described above formed on one side is processed, and a cup-shaped molded product is formed from the metal plate material (Step ST11). This molded product is a cap body (11) in which a plurality of flat sections (31), a plurality of concave sections (32), a female screw section (33), and a tamper evidence band section (34) are not formed. That is, the molded product is composed of a top plate section (21), a cylindrical skirt section (22) in which a plurality of flat sections (31), a plurality of concave sections (32), a female screw section (33), and a tamper evidence band section (34) are not formed, and a corner section (23).

[0072] Next, a sliding layer (41) is formed (step ST12). As a specific example, for instance, a cap body (11) is placed on a lower mold in a position where the top plate (21) is positioned downward in the direction of gravity. Then, a resin material for the sliding layer (41) that has been melted or softened is supplied onto the top plate (21), and the resin material supplied to the upper mold is compression molded to form the sliding layer (41).

[0073] Next, a sealing layer (42) is formed (step ST13). As a specific example, a resin material for a sealing layer (42) that is melted or softened is supplied onto a sliding layer (41), and the resin material supplied to an upper mold is compression molded to form a sealing layer (42) on the sliding layer (41). By this process, a sealing member (12) in which the sliding layer (41) and the sealing layer (42) are laminated is manufactured within the molded product.

[0074] Next, the molded product is processed to form the cap body (11) (Step ST14). As a specific example, a flat section (31), a vent slit (31a), a concave section (32), and a tamper evidence band section (34), etc., are formed on the skirt section (22) of the molded product. By this process, the cap body (11) is manufactured. Also, when forming the cap body (11), the sealing member (12) is removed from the molded product.

[0075] Next, a sealing member (12) is inserted into the manufactured cap body (11), and the cap (1) is manufactured (step ST15). By this process, the cap (1) is manufactured.

[0076] Next, a beverage or the like is filled into a separately manufactured can container (100). At this time, the can container (100) is positioned upright with the opening portion (110) located at the top. Next, a cap (1) is placed on the can container (100) (Step ST16). Specifically, the cap (1) is placed on the opening portion (110) of the can container (100) with the top plate portion (21) facing upward.

[0077] Additionally, when the cap (1) is positioned so that the top plate (21) is facing upward, the sealing member (12) descends by a certain distance in a direction separated from the top plate (21), and the sealing member (12) is supported at the end of the plate (31), thereby restricting movement in the downward direction. In this state, when the cap (1) is placed over the inlet (110), the thick portion (42d) of the sealing layer (42) of the sealing member (12) faces the inlet (110), and the inlet (110) and the thick portion (42d) come into contact as shown in ST16 of FIG. 6.

[0078] Next, the cap (1) is capped onto the can container (100) using the mold (200) of the molding device (Step ST17). In addition, as a specific example of capping, the cap (1) is placed over the opening portion (110), the corner portion (23) is drawn-molded, and the skirt portion (22) is roll-on-molded.

[0079] Here, the mold (200) is equipped with a first mold (210) for drawing molding a corner portion (23), a second mold (220) for rolling molding a skirt portion (22), and a driving mechanism for driving the first mold (210) and the second mold (220). Additionally, the first mold (210) is equipped with a fixed type (211) that contacts the top plate portion (21) and a movable type (212) that applies an axial load to the corner portion (23).

[0080] As shown in ST17 of FIG. 6, a specific example of capping using a mold (200) is described. First, the top plate portion (21) is pressed by a fixed mold (211), and the inlet portion (110) is pressed against the sealing member (12). At this time, the sealing member (12) is in a state where the thick portion (42d) of the sealing layer (42) is compressed by the inlet portion (110). With the top plate portion (21) and the sealing member (12) positioned between the inlet portion (110) and the fixed mold (211), a load directed downward in the axial direction is applied to the corner portion (23) by a movable mold (212), thereby shaping the corner portion (23) and tightening the corner portion (23) into a predetermined shape. Additionally, by rolling-on molding the skirt portion (22) with the second mold (220), a female screw portion (33) in the shape of the male screw portion (112) of the can container (100) is formed on the skirt portion (22).

[0081] After molding, the mold (200) is withdrawn from the cap (1), thereby the cap (1) is fixed to the opening (110) of the can container (100), and the capping of the cap (1) is completed (step ST18 of FIG. 6), and a bottle-shaped can filled with a beverage is manufactured.

[0082] According to the cap (1) configured in this manner, the inner resin film of the cap body (11) is configured to include a polyester resin and a lubricant. With this configuration, the cap (1) can be opened. If a hydrocarbon wax is used as a lubricant, the cap opening torque of the cap (1) can be significantly reduced, thereby significantly improving the cap opening performance of the cap (1). Furthermore, if the hydrocarbon wax is used in combination with a fatty acid ester wax as a lubricant, the 2nd torque of the cap (1) (i.e., the torque at the time of breakage of the breakage portion (34a) of the tamper evidence band portion (34) of the cap) can be further reduced compared to the case where the hydrocarbon wax is used alone, thereby further improving the cap opening performance of the cap (1).

[0083] Desirable Sun

[0084] The desirable sun is summarized and described below.

[0085] [1] A cap body having a disc-shaped top plate and a tube-shaped skirt portion installed on the periphery edge of the top plate, wherein the top plate comprises a substrate and a resin film installed on the inner side of the cap of the substrate, and the resin film comprises a polyester resin and a lubricant.

[0086] A sealing member installed separately from the above-mentioned cap body, facing the top plate portion, and having an outer diameter smaller than the inner diameter of the skirt portion.

[0087] A cap equipped with

[0088] [2] The above lubricant is a cap described in [1] containing a hydrocarbon wax.

[0089] [3] The cap described in [2], in which the hydrocarbon wax is polyethylene wax.

[0090] [4] The above lubricant further comprises a fatty acid ester-based wax. [2] or [3] Cap.

[0091] [5] The cap described in [4], in which the fatty acid ester wax is lanolin.

[0092] [6] A cap described in any one of [1] to [5], which is additionally equipped with a plurality of catches installed in the circumferential direction of the above skirt portion and which restrict and support the movement of the sealing member in the direction away from the above top plate portion.

[0093] [7] The above-mentioned catch is a cap described in [6] that protrudes inward in the diameter direction from the inner surface of the above-mentioned skirt part.

[0094] [8] A cap described in any one of [1] to [7], which is additionally equipped with a plurality of regulating members installed in the circumferential direction of the above skirt portion and regulating the movement of the sealing member in the diameter direction.

[0095] [9] The above-mentioned regulating part is a cap described in [8] that protrudes inward in the diameter direction from the inner surface of the above-mentioned skirt part.

[0096]

[10] The above regulation part is a cap described in [8] or [9] located on the top plate side rather than the part of the sealing member of the above catch part that contacts the above catch part.

[0097]

[11] The above-mentioned regulating part has an inner surface of the skirt part that is separated from the top plate part in the axial direction, and also has an inclined surface that is inclined toward the inner diameter direction [8] to

[10] described in any one of [8] to

[10] .

[0098]

[12] The diameter of the circle that is continuous at the bottom end in the axial direction of the plurality of inclined surfaces is set larger than the diameter of the circle that is continuous at the innermost end in the diameter direction of the plurality of locking parts

[11] .

[0099]

[13] The sealing member described above is a cap [1] to

[12] in which the outer edge is formed thinner than the sealing portion that contacts the opening of the container.

[0100]

[14] The sealing member above is

[0101] A sliding layer disposed on the top plate side, and

[0102] A sealing layer installed on the main surface opposite to the top plate side of the sliding layer and sealing the opening of the can container.

[0103] A cap described in any one of [1] to

[13] having [1].

[0104]

[15] The above sliding layer is a cap described in

[14] that is slidable with respect to the top plate.

[0105]

[16] The above sliding layer is installed on the outer edge side and has a thinner section than the center side

[14] or

[15] as described in the cap.

[0106]

[17] The above-described cap

[16] is installed at a position opposite to the point of deformation of the top plate portion during the drawing molding of the corner portion of the cap body.

[0107]

[18] The above-mentioned thin-walled portion is installed in a position adjacent in the axial direction to the portion facing the opening portion of the sealing layer when mounted on the can container

[16] or

[17] , the cap described therein.

[0108]

[19] The sealing member is a cap described in any one of

[16] to

[18] , wherein the portion facing the inlet is thicker than the other portion.

[0109]

[20] The above sliding layer is a cap described in any one of

[16] to

[19] in which the portion on the outer side in the diameter direction of the thin-walled portion is thicker than the thin-walled portion.

[0110] (Example)

[0111] The present invention is described below based on examples.

[0112] [Experiment 1]

[0113] In Experiment 1, the effect of adding a lubricant to the inner surface coating of a cap containing a polyester resin as the main component was investigated.

[0114] [1] Manufacture of bottle-type cans

[0115] Bottle-type cans of Examples 1 to 6 were manufactured as follows. The cap of the manufactured bottle-type can has the structure shown in Fig. 1.

[0116] (Example 1)

[0117] As the inner surface coating of the cap, a polyester resin coating containing polyethylene wax and lanolin as lubricants was used. The inner surface coating was applied to one side of an aluminum alloy plate (thickness: 0.23 mm) at a concentration of 50 mg / dm² 2 Baking was applied with the coating amount. Additionally, printing was performed on the other side of the main surface (outer surface of the cap). The obtained metal plate was formed into a cup-shaped cap body having a top plate and a skirt plate by drawing forming. The cap body had a height of approximately 18 mm and a weight of approximately 2.1 mg.

[0118] A sealing member was manufactured as follows using a cap body as a mold. A resin material constituting a sliding layer was supplied to the inner surface of the top plate portion of the cap body, and the sliding layer was formed by a mold. A resin material constituting a sealing layer was supplied onto the sliding layer, and the sealing layer was formed by a mold, thereby manufacturing a sealing member comprising a sliding layer and a sealing layer.

[0119] A sealing member was removed from the cap body, and a flat portion (reference numeral 31 in FIG. 1), a concave portion (reference numeral 32 in FIG. 1), and a tamper evidence band portion (reference numeral 34 in FIG. 1) were formed on the skirt portion of the cap body, and the sealing member was inserted into the cap body to manufacture the cap.

[0120] Capping of the cap onto the container opening was performed as follows. With the cap placed over the container opening so that the leading edge (curl portion) of the container opening and the sealing layer of the sealing member come into contact, a load was applied to the top plate portion of the cap body, and the skirt portion was rolled-on formed while drawing the corner portion downward. By doing this, the cap was wound and fixed to the container opening, and the bottle-type can of Example 1 was manufactured.

[0121] (Example 2)

[0122] A bottle-type can of Example 2 was manufactured in the same manner as Example 1, except that a polyester resin paint that does not contain a lubricant was used as the inner paint.

[0123] (Example 3)

[0124] A bottle-type can of Example 3 was manufactured in the same manner as Example 1, except that a polyester resin paint containing only lanolin as a lubricant was used as the inner paint.

[0125] (Example 4)

[0126] A bottle-type can of Example 4 was manufactured in the same manner as Example 1, except that a polyester resin paint containing only polyethylene wax as a lubricant was used as the inner paint.

[0127] (Example 5)

[0128] A bottle-type can of Example 5 was manufactured in the same manner as Example 1, except that a polyester resin paint containing polyethylene wax and lanolin as lubricants was used as the inner paint, but with the amount of lanolin added reduced by 25% compared to Example 1.

[0129] (Example 6)

[0130] A bottle-type can of Example 6 was manufactured in the same manner as Example 1, except that a polyester resin paint was used as an inner coating that contains polyethylene wax and lanolin as lubricants, but with the amount of polyethylene wax and lanolin added reduced by 25% compared to Example 1.

[0131] [2] Evaluation method

[0132] The cap openability of the bottle-type cans in Examples 1 to 6 was evaluated. The evaluation method is as follows.

[0133] (1) 1st torque and 2nd torque

[0134] The first torque is measured by fixing the body of a bottle-type can to a torque meter (Nihon Densan Shimpo Co., Ltd. TNK-50B-1), holding the cap, and rotating it in the direction of opening the cap. At that time, the peak value of the torque when the cap begins to move from the origin is defined as the "1st torque."

[0135] After measuring the 1st torque, the torque meter's measurement value is reset, and the cap is rotated again in the direction of opening the cap to sequentially break the break portion of the tamper evidence band. The peak torque value between the 1st torque and the time the cap is removed from the can container is defined as the "2nd torque."

[0136] (2) Angle of opening the stopper

[0137] The angle of opening the cap is measured by rotating the cap in the direction of opening from the closed state. The angle of rotation of the cap when the break portion of the tamper evidence band is completely broken is defined as the "angle of opening the cap."

[0138] [3] Evaluation results

[0139] The evaluation results are shown in Table 1.

[0140] lubricant Cap opening test polyethylene wax lanolin 1st Torque [Ncm] 2nd Torque [Ncm] Stopper opening angle[˚] Example 1 100 100 79 106 196 Example 2 0 0 177 166 200 Example 3 0 100 139 144 218 Example 4 100 0 79 117 205 Example 5 100 75 83 107 206 Example 6 75 75 83 105 222

[0141] In Table 1, the amount of each lubricant added is indicated by a relative value when the amount (mass) of each lubricant added in Example 1 is set to 100. In Table 1, the 1st torque indicates the peak value of the torque at the start of rotation of the cap, and the 2nd torque indicates the peak value of the torque at the break of the break portion of the tamper evidence band portion of the cap.

[0142] When the inner resin film of the cap body contains a lubricant along with a polyester resin, the cap's opening performance could be improved (see Examples 1 to 6). When polyethylene wax was used alone as a lubricant, the torque was significantly reduced, and the cap's opening performance could be significantly improved (see Examples 2 and 4). Furthermore, when polyethylene wax was used in combination with lanolin as a lubricant, the second torque was further reduced compared to the case where polyethylene wax was used alone, and the cap's opening performance could be further improved (see Examples 1 and 4 to 6).

[0143] [Experiment 2]

[0144] Experiment 2 shows the effect of adding a lubricant to an inner cap film mainly composed of polyester resin, compared with the effect of adding a lubricant to an inner cap film mainly composed of epoxyphenol resin.

[0145] A bottle-type can of Example 7 was manufactured using a polyester resin paint containing polyethylene wax and lanolin as a lubricant as the inner surface paint of the cap, in the same manner as in Experiment 1. Additionally, a bottle-type can of Example 8 was manufactured using an epoxyphenol resin paint containing polyethylene wax and lanolin as a lubricant as the inner surface paint of the cap, in the same manner as in Experiment 1.

[0146] For the bottle-type cans of Examples 7 and 8, the cap opening ability was evaluated using the same method as in Experiment 1. In addition, in Experiment 2, the evaluation was performed after storing the manufactured bottle-type cans at 55°C for 1 day. The evaluation results are shown in Table 2.

[0147] film Cap opening test profit lubricant 1st Torque [Ncm] 2nd Torque [Ncm] Stopper opening angle[˚] Example 7 Polyester polyethylene wax lanolin 87 85 212 Example 8 epoxyphenol Polyethylene wax lanolin 149 111 206

[0148] When the inner resin film of the cap body contains a lubricant along with a polyester resin, the cap's opening ability could be improved (see Example 7). On the other hand, when the inner resin film of the cap body contains a lubricant along with an epoxyphenol resin, the cap's opening torque could not be sufficiently reduced (see Example 8). This difference is thought to be due to the fact that, as discussed above, the polyester resin has a lower crosslinking density compared to the epoxyphenol resin, which allows particulate wax to be stably maintained on the surface of the resin film, and also allows molten wax present inside the resin film to seep out onto the surface. Explanation of the symbols

[0149] 1… Cap, 11… Cap body, 12… Sealing member, 12a… Flat section, 12b… Curved section, 21… Top plate section, 22… Skirt section, 23… Corner section, 31… Flat section, 31a… Vent slit, 32… Concave section, 32a… Inclined surface, 33… Female threaded section, 34… Tamper evidence band section, 34a… Break section, 41… Sliding layer, 41a… First flat section, 41b… First curved section, 41c… Protrusion section, 41d… Thin section, 41d1… Inclined surface, 41d2… Inclined surface, 42… Sealing layer, 42a… Second flat section, 42b… Second curved section, 42c… Depressed section, 42d… Thick section, 42d1… First projection, 42d2… Second projection, 100… Can container, 110… Inlet part, 111… Jaw part, 112… Male screw part, 113… Curl part, 200… Mold, 210… First mold, 211… Fixed type, 212… Movable type, 220… Second mold.

Claims

Claim 1 A cap characterized by having a disc-shaped top plate and a tube-shaped skirt portion installed on the periphery edge of the top plate, wherein the top plate comprises a substrate and a resin coating covering the substrate on the inner side of the cap, and the resin coating comprises a polyester resin and a lubricant, a cap body, and a sealing member that is installed within the cap body opposite the top plate and has an outer diameter smaller than the inner diameter of the skirt portion and is non-adherent to the cap body, wherein the lubricant comprises a hydrocarbon wax and a fatty acid ester wax, wherein the hydrocarbon wax is polyethylene wax and the fatty acid ester wax is lanolin. Claim 2 delete Claim 3 delete Claim 4 delete Claim 5 delete

Images