Welding method

Abstract

To provide a plug and a welding method capable of suitably welding the plug and a container body even in the case where the plug and an innermost layer of the container body are polyester resin.SOLUTION: A plug is made of polyester resin, and includes a cylindrical part, a disk-like flange part, and a convex director provided concentrically with an outer edge of the flange part on one surface of the flange part. In a welding method, the plug and a container body which includes a polyester resin layer as an innermost layer and in which an opening is formed are welded by inserting the cylindrical part of the plug in an opening of the container body, in a state where the director is in contact with the polyester layer, and by pressing a pressing part of a hone which is a substantially flat surface on the surface of the container body on the opposite side from the surface to which the director comes into contact.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a stopper and a welding method.

Background Art

[0002] There is known a packaging container in which a stopper is attached to a container body laminated with paper, a thermoplastic resin film, etc., and filled with liquids such as Japanese sake, shochu, wine, other beverages, and seasonings. The stopper is provided in an opening provided at the top of the container body, and the container body and the stopper are connected by ultrasonic welding or the like through a flange portion provided on the stopper (Patent Document 1).

[0003] As an example, with reference to FIG. 6, a general ultrasonic welding method for a container body and a stopper will be described. First, from the inside of the container body 200 (the surface on the side where the liquid is filled), the flange portion 111 is applied to the container body 200 in such a manner that the cylindrical portion of the stopper 400 is inserted into the opening 220 of the container body 200, and the pressing portion 310 of the horn 300 of the ultrasonic welding apparatus having a convex shape is pressed from the outside of the container body 200, and heat generated by ultrasonic vibration is applied to the container body 200 and the flange portion 111. Then, the sealant layer, which is the innermost layer of the container body 200 to which heat is applied, and a part of the flange portion 111 are melted, and the container body 200 and the stopper 400 are welded. Since the pressing portion 310 of the horn 300 has a convex shape, the pressing portion can be efficiently heated to a high temperature.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, when the stopper and the sealant layer, which is the innermost layer of the container body, are made of polyester resin, if the container body and the stopper are welded by the method shown in Fig. 6, the paper of the container body will turn black. This is because, in the case of a resin such as polyester resin with a high melting point and low flexibility, the energy and amplitude required for welding increase, and the paper of the container body becomes hot and burns. Therefore, it has been difficult to adopt polyester resin for the stopper and the sealant layer, which is the innermost layer of the container body.

[0006] The present invention has been made in view of such problems, and an object thereof is to provide a stopper and a welding method capable of suitably welding the stopper and the container body even when the innermost layers of the stopper and the container body are made of polyester resin.

Means for Solving the Problems

[0008] One aspect of the present invention for solving the above problems is a method of welding a stopper and a container body. The stopper is made of polyester resin and includes a cylindrical portion, a disc-shaped flange portion, a convex director provided concentrically with the outer edge of the flange portion on one surface of the flange portion, and a concave portion adjacent to the director and provided on the center side of the concentric circle in the flange portion rather than the director. The container body includes a polyester resin layer as the innermost layer and has an opening formed therein. In a cross-section by a plane including the axis of the cylindrical portion, the cross-sectional area of the director is larger than the cross-sectional area of the concave portion. The cylindrical portion of the stopper is inserted into the opening of the container body, and the edge of the opening of the container body is arranged so as to be located on the concave portion when viewed from the axial direction of the cylindrical portion. In a state where the director is in contact with the polyester resin layer, the pressing portion of the horn, which is the surface, is pressed against the surface of the container body on the side opposite to the surface in contact with the director for welding. , flat It is a welding method.

Effects of the Invention

[0009] According to the present invention, even when the innermost layers of the stopper and the container body are made of polyester resin, it is possible to provide a stopper and a welding method capable of suitably welding the stopper and the container body.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Embodiment for Carrying Out the Invention

[0011] Hereinafter, a stopper and a welding method according to an embodiment of the present invention will be described with reference to the drawings. Fig. 1 is a diagram for explaining the welding method of a stopper according to an embodiment of the present invention. Figs. 2 and 3 are longitudinal sectional views of a stopper according to an embodiment of the present invention. Note that Figs. 1 to 3 show a state where a cap is not attached to the stopper, but welding may be performed with the cap attached. Further, since the longitudinal sectional view of the stopper is bilaterally symmetric, the longitudinal sectional views of the stoppers in Figs. 2 and 3 show only the left half for convenience.

[0012] <Embodiment> The packaging container 100 includes a stopper 1 and a container body 2. Hereinafter, the stopper, the container body, and their welding methods will be described separately.

[0013] (Stopper) The stopper 1 according to the embodiment of the present invention has a cylindrical portion 10 and a flange portion 11. The stopper 1 is made of a polyester resin as a material and is used by being attached to the container body 2. The stopper 1 may appropriately include a cap, a packing, etc.

[0014] The cylindrical portion 10 is a cylindrical part that serves as a spout when taking out the contents housed in the container body 2. As shown in FIG. 1, the cylindrical portion 10 may be provided with a screw on its outer peripheral surface so that a cap can be attached by screwing.

[0015] The flange portion 11 is provided for welding the plug 1 to the container body 2. The flange portion 11 is formed in a disk shape so as to extend outward from one end of the cylindrical portion 10, and is provided with a convex director 12 on the surface on the side of the cylindrical portion 10. Further, the flange portion may be provided with a concave portion 13a adjacent to the director 12, like the flange portion 11a of the plug 1a shown in FIG. 2.

[0016] The director 12 is a convex portion for concentrating ultrasonic vibration to enable stable welding when performing ultrasonic welding. The director 12 is formed concentrically with the outer edge of the flange portion 11 on the surface of the flange portion 11 on the side of the cylindrical portion 10, and more specifically, refers to a portion exceeding the plane defining the upper surface of the flange portion 11. As an example, the director 12 has a substantially trapezoidal cross-sectional shape. Note that the cross-section is a plane including the axis of the cylindrical portion 10, and the same shall apply hereinafter.

[0017] The concave portion 13a may be provided to improve the fluidity of the resin during welding. The concave portion 13a is provided adjacent to the director 12, and more specifically, refers to a void portion below the plane defining the upper surface of the flange portion 11. As shown in FIG. 2, the concave portion 13a may be provided one by one on the center side and the outer edge side of the flange portion 11a with respect to the director 12, or only one of them may be provided. As an example, the concave portion 13a has a substantially inverted trapezoidal cross-sectional shape.

[0018] Furthermore, the director and the concave portion may have a curved cross-sectional shape at one or both of the boundary between the upper surface and the side surface of the director 12b and the boundary between the side surface of the director 12b and the bottom surface of the concave portion 13b, like the director 12b and the concave portion 13b provided on the flange portion 11b of the plug 1b shown in FIG. 3.

[0019] (Container body) Next, the container body 2 connected to the stopper 1 by welding will be described. The container body 2 is a member including at least paper and a polyester resin layer which is a sealant layer, and the polyester resin layer is the innermost layer of the container body 2. The container body 2 has, for example, a prismatic shape with one end closed including a top and a bottom, and a circular opening 20 is formed at the top. The container body 2 and the stopper 1 can be welded with the cylindrical portion 10 inserted through the opening 20 from the side for storing the contents of the container body 2 (inside the container body 2). Note that the container body 2 may appropriately include other layers such as a gas barrier layer made of aluminum or the like.

[0020] (Welding method) Next, the welding method used to weld the stopper 1 and the container body 2 will be described.

[0021] The flange portion 11 is brought into contact with the container body 2 in such a manner that the cylindrical portion 10 of the stopper 1 is inserted through the opening 20 from the inside of the container body 2. At this time, the director 12 abuts against the polyester resin layer inside the container body 2. In this state, as shown in FIG. 1, the horn 3 is applied from the outside of the container body 2.

[0022] Specifically, the horn 3 is a horn of an ultrasonic welding apparatus. In the horn 3, the pressing portion 31 which is the surface on the side pressing the container body 2 is substantially flat, and the width of the pressing portion 31 is larger than the width of the director 12. Ultrasonic waves having a predetermined frequency are supplied to the pressing portion 31, and the pressing portion 31 is heated (generates heat) by the vibration. Thereby, the inner surface of the polyester resin layer of the container body around the opening 20 and the director 12 of the stopper 1 are melted, and the stopper 1 and the container body 2 can be welded. Note that, as shown in FIG. 3, when one or both of the boundary between the upper surface and the side surface of the director 12b and the boundary between the side surface of the director 12b and the bottom surface of the recess 13b have a cross-sectional shape of a curved surface, the fluidity of the resin during welding of the stopper 1b and the container body 2 is further improved.

[0023] As described above, the director 12 is formed on the flange portion 11 of the stopper 1, and the pressing portion 31 of the horn 3 that presses the container body 2 and the director 12 from the outside of the container body 2 is substantially flat. Therefore, the energy and pressure from the horn 3 are concentrated on the director 12, and the director 12 can be efficiently softened, so that welding can be performed before the heat diffuses and the paper turns black. Thus, even if the innermost layer of the stopper 1 and the container body 2 is a polyester resin layer, the stopper 1 and the container body 2 can be welded without the paper of the container body 2 turning black.

[0024] <Modification> Next, the stopper and the welding method according to the modification will be described with reference to FIGS. 4(a) and 4(b). FIG. 4(a) is a longitudinal sectional view of the stopper 1c according to the modification before welding, and FIG. 4(b) is a longitudinal sectional view of the stopper 1c according to the modification after welding. Note that FIG. 4 shows a state where the cap is not attached to the stopper 1c, but welding may be performed with the cap attached. Also, since the longitudinal sectional view of the stopper is bilaterally symmetric, the longitudinal sectional view of the stopper 1c in FIG. 4 shows only the left half for convenience. Here, the differences from the above-described embodiment will be mainly described, and common matters will be described as necessary.

[0025] As shown in FIG. 4(a), the recess 13c is provided adjacent to the center side of the flange portion 11c with respect to the director 12c. Here, in a cross section by a plane including the axis of the cylindrical portion 10, the cross-sectional area of the director 12c is larger than the cross-sectional area of the recess 13c. Further, the end face, which is the side face of the edge of the opening 20 of the container body 2, is provided so as to be located above the recess 13c when viewed from the axial direction of the cylindrical portion 10.

[0026] Thereby, as shown in FIG. 4(b), when the stopper 1c and the container body 2 are welded, the melted director 12c flows into the recess 13c and adheres to the end face of the opening 20, so that the end face of the opening 20 can be protected. Thereby, it is possible to prevent moisture outside the packaging container 100c, such as shower water for cooling the packaging container 100c and the contents adhering to the outer periphery of the stopper 1c during use of the packaging container 100c, from entering between the layers of the container body 2.

[0027] Although the positions of the director 12c and the recess 13c from the center of the flange portion 11c are different, the director 12c and the recess 13c are provided adjacent to each other, and since the recess 13c is located on the inner peripheral side of the director 12c, if the cross-sectional area of the director 12c is larger than the cross-sectional area of the recess 13c, the melt of the director 12c can sufficiently fill the recess 13c and protect the end face of the opening 20.

Example

[0028] In Examples 1 and 2 and Comparative Examples 1 and 2, evaluations were made on the weldability and the presence or absence of blackening of the paper of the container body. In Examples 3 to 8, in addition to the evaluations on the weldability and the presence or absence of blackening of the paper of the container body, evaluations were also made on the protectability of the end face of the opening 20.

[0029] (Example 1) A plug 1 provided with a director 12 on the flange portion 11 as shown in FIG. 1 was manufactured from polyester. From the outside of the container body, a container body 2 having a layer structure of polyethylene (PE), paper, polyethylene (PE), polyethylene terephthalate (PET) or vapor-deposited polyethylene terephthalate (vapor-deposited PET), polyethylene (PE), and polyester was manufactured. Note that the polyester layer serves as the sealant layer. For welding, a horn 3 with a substantially flat pressing portion 31 was used, and the pressing force was set to 350 N. The combinations of welding energy and amplitude were set to four types: (welding energy, amplitude) = (110 J, 80%), (110 J, 90%), (130 J, 80%), and (150 J, 100%), and welding was performed under each condition.

[0030] (Example 2) Welding was performed in the same manner as in Example 1, except that a plug 1a as shown in FIG. 2 having one recess 13a each on the center side and the outer edge side of the flange portion 11a with respect to the director 12 was manufactured from polyester.

[0031] (Comparative Example 1) In the stopper 1 shown in Fig. 1, the flange portion was made of a flat shape without a director and manufactured from polyester. In the horn 3 shown in Fig. 1, the shape of the pressing portion of the horn was made convex, and welding was performed in the same manner as in Example 1 except that the combination of welding energy and amplitude was set to four patterns: (welding energy, amplitude) = (150 J, 90%), (150 J, 100%), (160 J, 90%), (160 J, 100%).

[0032] (Comparative Example 2) In the stopper 1 shown in Fig. 1, the flange portion was made of a flat shape without a director and manufactured from polyester, and welding was performed in the same manner as in Example 1 except that the combination of welding energy and amplitude was set to four patterns: (welding energy, amplitude) = (150 J, 90%), (150 J, 100%), (160 J, 90%), (180 J, 100%).

[0033] (Example 3) Using the stopper 1c according to the modified example shown in Fig. 4, welding of the stopper 1c and the container body 2 was performed. At this time, the cross-sectional shape of the director 12c was made into a substantially trapezoid with the upper base length A, lower base length B, and height C as shown in Fig. 5. Also, the cross-sectional shape of the cross-sectional area of the concave portion 13c was made into a substantially inverted trapezoid with the upper base length a, lower base length b, and height c as shown in Fig. 5. In Example 3, A = 0.2 mm, B = 0.3 mm, C = 0.6 mm, a = 0.3, b = 0.2, c = 0.5, and the cross-sectional area of the director 12c and the cross-sectional area of the concave portion 13c were made 0.15 mm 2 , 0.13 mm 2 respectively. The end face, which is the side face of the edge of the opening 20 of the container body 2, was arranged and welded so as to be located on the concave portion 13c when viewed from the axial direction of the cylindrical portion 10.

[0034] (Example 4) A = 0.3 mm, B = 0.4 mm, C = 0.5 mm, a = 0.3, b = 0.2, c = 0.5, and the cross-sectional area of the director 12c and the cross-sectional area of the concave portion 13c were made 0.18 mm 2 , 0.13 mm 2 respectively, and otherwise it was the same as in Example 3.

[0035] (Example 5) Set A = 0.2 mm, B = 0.6 mm, C = 0.4 mm, a = 0.6, b = 0.2, c = 0.3, and set the cross-sectional area of the director 12c and the cross-sectional area of the recess 13c to 0.16 mm 2 , 0.12 mm 2 respectively. Otherwise, it is the same as Example 3.

[0036] (Example 6) Set A = 0.2 mm, B = 0.3 mm, C = 0.5 mm, a = 0.3, b = 0.2, c = 0.6, and set the cross-sectional area of the director 12c and the cross-sectional area of the recess to 0.13 mm 2 , 0.15 mm 2 respectively. Otherwise, it is the same as Example 3.

[0037] (Example 7) Set A = 0.3 mm, B = 0.4 mm, C = 0.5 mm, a = 0.4, b = 0.3, c = 0.5, and set the cross-sectional area of the director 12c and the cross-sectional area of the recess 13c to 0.18 mm 2 , 0.18 mm 2 respectively. Otherwise, it is the same as Example 3.

[0038] (Example 8) Set A = 0.2 mm, B = 0.6 mm, C = 0.3 mm, a = 0.6, b = 0.2, c = 0.4, and set the cross-sectional area of the director 12c and the cross-sectional area of the recess 13c to 0.12 mm 2 , 0.16 mm 2 respectively. Otherwise, it is the same as Example 3.

[0039] (Evaluation Results) First, the evaluation results of Examples 1 and 2 and Comparative Examples 1 and 2 will be described. In the packaging containers of each example and comparative example, the weldability and blackening of the paper were visually judged. The evaluation results are shown in Tables 1 to 4 respectively.

[0040]

Table 1

[0041]

Table 2

[0042]

Table 3

[0043]

Table 4

[0044] The evaluation results of Example 1 are shown in Table 1. In Example 1, welding of the stopper and the container body was possible under the conditions of energy of 130 J or more and amplitude of 80% or more, and even when welded, the paper did not turn black.

[0045] The evaluation results of Example 2 are shown in Table 2. In Example 2, welding of the stopper and the container body was possible under the conditions of energy of 110 J or more and amplitude of 80% or more, and in all cases, the paper did not turn black. Therefore, it can be seen that providing a concave portion in addition to the director in the flange portion widens the range of allowable welding conditions.

[0046] The evaluation results of Comparative Example 1 are shown in Table 3. In Comparative Example 1, welding was possible when the energy was 150 J or more and the amplitude was 100%, or when the energy was 160 J or more and the amplitude was 100%, but the paper turned black under any conditions regardless of welding or non-welding.

[0047] The evaluation results of Comparative Example 2 are shown in Table 4. In Comparative Example 2, welding was slightly possible only under the condition of energy of 180 J and amplitude of 100%, but the paper turned black.

[0048] Next, the evaluation results of Examples 3 to 8 will be described. In any of the examples, suitable welding conditions were adjusted to enable suitable welding, and it was confirmed that there was no blackening. Further, in each packaging container, it was determined visually whether or not the end face was protected. The results are shown in Table 5. On the end face of the opening 20 of the container body 2 in Examples 3 to 5 where the cross-sectional area of the director 12c was larger than the cross-sectional area of the recess 13c, the melted director reached and the end face was protected. However, on the end face of the opening 20 of the container body 2 in Examples 6 to 8 where the cross-sectional area of the director was less than or equal to the cross-sectional area of the recess, the melted director did not reach and the end face was not protected.

[0049]

Table 5

Industrial Applicability

[0050] The present invention can be used for a packaging container having a stopper.

Explanation of Signs

[0051] 1, 1a, 1b, 1c Stopper 2 Container body 10 Cylindrical portion 11, 11a, 11b, 11c Flange portion 12, 12b, 12c Director 13a, 13b, 13c Recess 20 Opening 3 Horn 31 Pressing portion 100 Packaging container

Claims

1. A method for welding a plug to a container body, comprising the steps of: The plug is made of polyester resin and comprises a tubular portion, a disk-shaped flange portion, a convex director provided on one surface of the flange portion in a concentric circle with an outer edge of the flange portion, and a concave portion adjacent to the director and provided closer to the center of the concentric circle in the flange portion than the director, The container body includes a polyester resin layer as an innermost layer, and an opening is formed therein. In a cross section taken along a plane including an axis of the cylindrical portion, a cross-sectional area of ​​the director is larger than a cross-sectional area of ​​the recess, A welding method comprising: inserting the tubular portion of the plug into the opening of the container body; positioning an edge of the opening of the container body so that it is positioned on the recess when viewed from the axial direction of the tubular portion; and, with the director and the polyester resin layer in contact, pressing a flat pressing portion of a horn against the surface of the container body opposite the surface with which the director is in contact to weld them.

2. the boundary between the top and side surfaces of the director; and The welding method according to claim 1 , wherein one or both of the boundaries between the bottom surface and the side surface of the recess has a curved cross-sectional shape.

Images