JP5234989B2 - Inner bag for cylindrical container and manufacturing method thereof - Google Patents

Description

  The present invention relates to an inner bag for a cylindrical container to be mounted inside a cylindrical container such as a drum can and a method for manufacturing the same, and can be brought into close contact with the inside and bottom of the container while ensuring the strength of the bottom circumference (edge). The present invention relates to an inner bag for a cylindrical container and a method for manufacturing the same.

  In general, since the inner bag for a cylindrical container is required to be inexpensive, a cylindrical container is often used in which one cylindrical film is divided into a predetermined length and one end edge thereof is thermocompression bonded. In addition to the ones proposed in Patent Document 1 and Patent Document 2 below, a polygonal seal or semi-elliptical seal is applied to the bottom, and the entire interior of the cylindrical container is closely adhered to the cylindrical container. There are several inner bags for cylindrical containers, such as those that prevent breakage, those that can be obtained from a single bag body by folding the sheet, etc., and those that have a round bottom. Are known.

JP 2003-291985 A Japanese Patent No. 3817714

  In the invention relating to the method for producing the container can interior bag proposed in Patent Document 1, the bottom portion of the bottomed bag member is arranged in the direction toward the inner side of the bottomed bag member with the substantially central portion of the bottom fold. A bottomed bag member provided with the polygonal bottom side by folding and removing the corner triangular piece portions formed at both ends of the bottom side fold by welding cutting. Inflated into a rectangular tube shape and covered with a molding die for bottom molding, the bottom of the polygon is heated by a heater, heat contracted along the molding die, and an interior bag is formed, Such an inner bag for a container can only be used as one member of a bottomed bag body member, and is heat-shrinked over the outer periphery of the forming die, so that the bottom part is easily formed into a predetermined shape. It can be easily and inexpensively adapted to the inner shape of the cylindrical container.

  Further, in the invention related to the method for manufacturing the container can interior bag proposed in Patent Document 2, a short tube-shaped outer ring piece movable along the longitudinal direction of the interior bag to be molded, and the inner peripheral side thereof An inner bag forming mold comprising a disk-shaped receiving plate and a fixed receiving plate is formed in accordance with the shape of the inner bag to be formed, and the outer ring piece is made of a heat-shrinkable synthetic resin having a cylindrical shape on the outer periphery. The inner bag peripheral wall material is externally fitted, and one end portion side of the inner bag peripheral wall material is protruded from the tip of the outer ring piece by a length that forms a weld piece, and this protruding portion is opposed to the inner bag forming mold. Heat-shrink in the radial direction by heating with a heater arranged in this way, forming a welding piece so as to hang down from the outer peripheral edge of the inner ring forming mold outer ring piece to the inner peripheral direction and from the outer peripheral edge Next, the welding piece in the suspended state and the outer ring piece at the end It is adjusted so that it is moved up and down at the time of welding, and is superimposed almost horizontally on the welding piece in a horizontal state, and the overlapped portion of the end member cut in advance along the inner bottom surface in the container can is formed into a ring-shaped heat sealer. It is characterized in that the inner bag for container cans is manufactured by integrally welding with, and heat shrinkage is performed almost uniformly by preventing the application of non-uniform force when the welded piece is formed by heat shrinkage. By being broken, it can be formed without reducing the thickness of the sheet and without causing wrinkles, and at the time of welding, end members are stacked on the welding piece and welded in a ring shape with a heat sealer. Therefore, it is said that welding with the end member can be performed reliably without causing pinholes or steps, and manufacturing can be performed easily and reliably.

  However, existing products used as inner bags for cylindrical containers, such as those obtained by dividing a cylindrical film into a predetermined length and thermocompression bonding one end edge thereof, are heated in a semi-dissolved state at the bottom. Since it is bent, there is a problem that the thickness of the portion contacting the bottom of the cylindrical container and the vicinity of the bottom circumference cannot be made uniform. In addition, even if a polygonal seal or semi-elliptical seal is applied to the bottom surface, the seal part contacts the inside of the cylindrical container, and a gap is formed near the bottom of the cylindrical container or the bottom of the cylinder. There is a problem. The invention proposed in Patent Document 1 also uses heat shrinkage to match the shape of the inner part of the cylindrical container, so there is a problem that the thickness of the inner bag is not uniform, causing pinholes and tearing. There are challenges. In the invention proposed in Patent Document 2, since the bottom shape is a perfect circle, there is no gap in the vicinity of the bottom of the cylindrical container or the circumference of the bottom, so the problem that the inner bag is not sufficiently adapted to the cylindrical container is solved. However, it consists of a single sheet with a thin boundary between the bottom surface and the side surface, and the strength on the circumference of the bottom surface (edge) is not necessarily ensured. There remains a problem that it is difficult to completely remove the cause of the tear due to contact near the bottom circumference of the shaped container. Furthermore, there is a problem that the effect of heating the protruding portion on the one end portion side of the inner bag peripheral wall material with the heater affects the entire inner bag peripheral wall material, and the strength of the inner bag for the container can itself is concerned.

  The present invention is proposed from the above situation, and while ensuring sufficient strength of itself, it also secures the strength of the circumference (edge) of the bottom surface and eliminates the cause of pinholes and breakage, while the inner surface of the cylindrical container It is another object of the present invention to provide an inner bag for a cylindrical container that can be brought into close contact with both the circular bottom surface and easy to manufacture, and a method for manufacturing the same.

  In order to achieve the above-mentioned object, an inner bag for a cylindrical container according to the present invention has a length of an inner periphery of a predetermined cylindrical container, and is provided with a glue margin portion welded to both ends in the length direction. The heat-shrinkable sheet is welded with a part projecting downward at the lower part of the sheet, the glue margins are welded to form a cylinder, and the heat projecting from the lower part of the tubular sheet A part of the shrinkable sheet is heated and contracted to bend inward, and a circular bottom sheet is welded to a part of the bent heat-shrinkable sheet.

  In addition, the method for manufacturing an inner bag for a cylindrical container according to the present invention includes a lower part of a sheet having an inner peripheral length of a predetermined cylindrical container and having adhesive margin portions welded to both ends in the length direction. And a step of welding a heat-shrinkable sheet by projecting a part downward, a step of welding the glue margins to form a cylinder, and the heat projecting from the lower part of the tubular sheet And a step of heating and shrinking a part of the shrinkable sheet to bend inward, and welding a circular bottom sheet to the part of the folded heat-shrinkable sheet.

  In the inner bag for a cylindrical container according to the present invention, first, a predetermined length of the inner circumference of the cylindrical container is provided at a lower portion of a sheet having adhesive margin portions welded to both ends in the length direction. Since the heat-shrinkable sheet is welded with the portion protruding downward, the sheet and the heat-shrinkable sheet can be welded in a flat state. Furthermore, both ends of the adhesive margin part are welded to form a cylinder, and a part of the heat-shrinkable sheet protruding from the lower part of the cylinder-shaped sheet is heated and contracted to bend inward, and this bent heat Since the circular bottom sheet is welded to a part of the shrinkable sheet, the thickness (strength) of the rising part is increased because the heat-shrinkable sheet is applied to the boundary part (rising part) between the sheet and the bottom sheet. In the secured state, it can be brought into contact with the vicinity of the circumference of the bottom of the cylindrical container, and the cause of breakage, particularly the cause of breakage due to contact near the circumference of the bottom of the cylindrical container can be effectively removed.

  Also, a part of the heat-shrinkable sheet protruding from the lower part of the cylindrical sheet is heated and bent inward, and a circular bottom sheet is welded to a part of the bent heat-shrinkable sheet. The heat-shrinkable sheet and the bottom sheet can be welded in a flat state, and heat is not applied to the bottom sheet, so that the portion that comes into contact with the bottom of the cylindrical container or the vicinity of the bottom circumference The thickness of the inner bag can be made uniform, and the effect of heating the heat-shrinkable sheet does not reach the entire sheet, so that the strength of the inner bag itself does not become a problem. Further, since the bottom sheet is circular, for example, a perfect circle, there is no gap near the bottom of the cylindrical container or the circumference of the bottom, and it is not folded or directly sealed. The inner bag for dexterity can be easily manufactured.

  In the method for manufacturing an inner bag for a cylindrical container according to the present invention, first, a sheet having a predetermined cylindrical container inner peripheral length and having adhesive margin portions welded to both ends in the length direction. Since the heat shrinkable sheet is welded with a part protruding downward at the lower part of the sheet, the sheet and the heat shrinkable sheet can be welded in a flat state. Furthermore, after the step of welding the two ends of the glue margin part to form a cylinder, a part of the heat-shrinkable sheet protruding from the lower part of the cylinder-shaped sheet is heated and contracted to be folded inward. Because it has a process of welding a circular bottom sheet to a part of the heat-shrinkable sheet, the heat-shrinkable sheet is applied to the boundary part (rising part) between the sheet and the bottom sheet. The inner bag can be brought into contact with the vicinity of the bottom circumference of the cylindrical container while ensuring the thickness (strength) of the rising portion, and causes of breakage, etc., especially in the vicinity of the bottom circumference of the cylindrical container, etc. It is possible to effectively remove the cause of tearing.

  Also, a step of heating and shrinking a part of the heat-shrinkable sheet protruding from the lower part of the cylindrical sheet and bending it inward, and welding a circular bottom sheet to a part of the folded heat-shrinkable sheet Since the heat-shrinkable sheet and the bottom sheet can be welded in a flat state and manufactured without applying heat to the bottom sheet, the produced inner bag for a cylindrical container The thickness of the portion that contacts the bottom and the vicinity of the bottom circumference can be made uniform, and the effect of heating the heat-shrinkable sheet does not reach the entire sheet, and the strength of the inner bag itself does not become a problem. . And since the bottom sheet can be manufactured as a circle, for example, a perfect circle, there is no gap near the bottom of the cylindrical container and the circumference of the bottom, and it is not manufactured by folding or directly sealing. And the manufacturing method of the inner bag for cylindrical containers which concerns on this invention can be made easy.

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic perspective view of the inner bag for cylindrical containers of Example 1 which concerns on this invention, Comprising: The thing of the state fractured | ruptured for description is shown. It is explanatory drawing explaining the component in the inner bag for cylindrical containers of Example 1, (a) shows a trunk | drum sheet piece, (b) shows a heat-shrink sheet | seat, (c) is The bottom sheet piece is shown. It is explanatory drawing explaining the brazing sheet in the middle of manufacture in the inner bag for cylindrical containers of Example 1, Comprising: (a) shows the schematic whole of a brazing sheet, (b) is the principal part of a brazing sheet. Indicates. It is a schematic perspective view which shows the general | schematic whole of the sheet | seat (cylinder shape) in the middle of manufacture in the inner bag for cylindrical containers of Example 1. FIG. It is a schematic perspective view of the inner bag for cylindrical containers of Example 2 which concerns on this invention. It is a schematic perspective view of the inner bag for cylindrical containers of Example 3 which concerns on this invention. It is a schematic perspective view of the inner bag for cylindrical containers of Example 4 which concerns on this invention.

  Hereinafter, several embodiments of the inner bag for a cylindrical container and the manufacturing method thereof according to the present invention will be described in detail with reference to the drawings.

Example 1
As shown in FIG. 1, the inner bag 10 for a cylindrical container according to the present invention has a predetermined cylindrical container, for example, the length of the inner periphery of a drum can to be used. A sheet provided with an adhesive margin part 11a serving as a welding part, for example, a synthetic resin body sheet piece 11 and a lower part of the body sheet piece 11 are welded, and a part to be heated 12a is disposed on the inner side. A heat-shrinkable sheet that is bent into a heat-shrinkable sheet, for example, a heat-shrinkable sheet piece 12 made of synthetic resin, and a circular bottom sheet that is welded to the heated portion 12a of the heat-shrinkable sheet piece 12, such as synthetic resin The bottom sheet piece 13 is made of.

  As shown in FIG. 2A, the body sheet piece 11 has a predetermined cylindrical container, for example, the length of the inner periphery of the drum can to be used, and is welded to both ends in the length direction. This is a sheet piece made of a synthetic resin that is cut into a rectangle with a glue margin 11a for forming a cylindrical shape. For example, a general-purpose plastic sheet can be used.

As shown in FIG. 2B, the heat-shrinkable sheet piece 12 has, for example, substantially the same length as that of the body sheet piece 11, and is provided with paste margin portions 12b at both ends in the length direction. This is a relatively elongated strip-like sheet piece having a width capable of providing a welded part 12c welded to the piece 11 and a heated part 12a welded to the bottom sheet 13, and is directly heated by a jig or the like. It has the property of shrinking. In Example 1, for example, a synthetic resin, particularly a polyolefin-based one is used as the heat-shrinkable sheet piece 12.
The heat-shrinkable sheet in the present invention is a suitable material as long as it is a material that has wear resistance against contact and rubbing with the inside of a cylindrical container such as a drum can and has a property of shrinking when directly heated. Can be used as

  As shown in FIG. 2C, the bottom sheet piece 13 is a synthetic resin sheet piece cut into a circular shape, for example, a perfect circle, having a diameter smaller than the inner diameter of the drum can to be used by several mm, for example, 5 mm. It is. Note that the body sheet piece 11 and the bottom sheet piece 13 are provided with different names for the sake of explanation, and the same material may be used, or different materials may be used. Good. In addition, the thickness of the bottom sheet piece 13 and the thickness of the body sheet piece 11 ensure, for example, the bottom sheet piece 13 and the body sheet piece 11 in order to ensure wear resistance against contact and rubbing with the bottom of the cylindrical container. It is also possible to appropriately change the thickness, for example. Furthermore, the bottom sheet piece 13 can be carried out even if it is a circle having the same diameter as the inner diameter of the drum can to be used, but it can be cut into a circle 2 mm to 50 mm smaller than the inner diameter of the drum can to be used. It is preferable from the viewpoint of manufacturing efficiency of the inner bag 10 for a cylindrical container according to the present invention.

Here, the welding of the body sheet piece 11 and the heat-shrinkable sheet piece 12 of the cylindrical container inner bag 10 according to the present invention is performed with the heat-shrinkable property while projecting the heated portion 12a to the lower part of the body-sheet piece 11. The welded portions 12c of the sheet piece 12 are aligned in a flat state, and the adhesive margin portions 12b at both ends of the heat-shrinkable sheet piece 12 are aligned in a flat state to the adhesive margin portions 11a at both ends of the body sheet piece 11. Are welded to each other.
In addition, the heat-shrinkable sheet piece 12 and the bottom sheet piece 13 are welded to each other by joining the body sheet piece 11 and the heat-shrinkable sheet piece 12 to each other and welding the paste margin portions 11a and 12b at both ends. After that, the heated portion 12a of the heat-shrinkable sheet piece 12 protruding from the lower part of the body sheet piece 11 is heated and contracted by a jig and is bent inward. The bottom sheet piece 13 is welded to the heated part 12a of the sheet piece 12 in a flat state.

  Next, the manufacturing method of the inner bag for cylindrical containers which concerns on this invention is demonstrated, referring FIG. 3, FIG.

  First, the welded portion 12c of the heat-shrinkable sheet piece 12 is arranged in a flat state while projecting the heated portion 12a to the lower part of the trunk sheet piece 11, and the glue margin portions 11a at both ends of the trunk sheet piece 11 are arranged. The adhesive margins 12b of the heat-shrinkable sheet piece 12 are aligned and welded in a flat state, and the heat-shrinkable sheet piece 12 is formed under the body sheet piece 11 as shown in FIG. The brazed sheet A is thus welded. In particular, in Example 1, as shown in FIG. 3 (b), the welded portion 12c of the heat-shrinkable sheet piece 12 is placed on the lower part of the body sheet piece 11, and the heat sealer is used, for example, from above. Weld in a flat state. Then, the brazed sheet A is formed in a state in which the heated portion 12a of the heat-shrinkable sheet 12 protrudes downward from the welded portion between the body sheet piece 11 and the heat-shrinkable sheet piece 12.

  Subsequently, the adhesive margins 11a and 12b at both ends of the brazed sheet A are welded to form a cylindrical sheet B as shown in FIG. In this step, as shown in FIG. 4, when the brazed sheet A is formed into a cylindrical shape, the adhesive margin portions 11a and 12b coming to the inner surface side are welded, and the adhesive margin portions 11a and 12b protrude outward. The sheet B is used.

  Then, in order to heat the heated portion 12a of the heat-shrinkable sheet piece 12 protruding from the body sheet piece 11 in the tubular sheet B, the tubular sheet B is heated with the heat-shrinkable sheet. The side to which the piece 12 is welded is turned upward and fixed in a predetermined cylindrical shape, and then heated by applying a molding jig to the heated portion 12a protruding from the predetermined cylindrical shape. If it does so, the to-be-heated part 12a will bend | fold inside the cylindrical sheet | seat B by own heat shrinkability. At this time, a portion other than the heated portion 12a of the cylindrical sheet B is used for molding so that the thickness of the inner bag for the cylindrical container at the time of completion is uniform, and so as not to cause a pinhole or breakage. It is preferable to check whether or not it is heated by a jig.

Finally, in a state where the cylindrical sheet B is in a predetermined mold, a round bottom sheet piece 13 having a diameter 5 mm smaller than the inner diameter of the drum can to be used is adjusted so as to match the bent heated portion 12a. It arrange | positions and it welds in a flat state, and forms the inner bag 10 for cylindrical containers as shown in FIG.
Alternatively, the tubular sheet B may be pulled out of a predetermined mold, and the bottom sheet piece 13 may be inserted from the body sheet piece 11 side of the tubular sheet B, and may be welded so as to match the bent heated portion 12a. That is, the welding of the bottom sheet piece 13 to the heated part 12a to be bent may be appropriately selected from the viewpoint of manufacturing efficiency or the like depending on whether the welding is performed from the inside or the outside of the tubular sheet B.

  Thus, the inner bag 10 for a cylindrical container according to the present invention is characterized in that it is composed of three parts: a trunk sheet piece 11, a heat-shrinkable sheet piece 12, and a bottom sheet piece 13. According to the characteristics, the body sheet piece 11 and the heat-shrinkable sheet piece 12 are welded in a flat state, and the heated portion 12a and the bottom sheet piece 13 of the heat-shrinkable sheet piece 12 heated by a molding jig are used. It can be manufactured by a very easy manufacturing method in which welding is performed in a flat state. Furthermore, unlike the conventional case, since the heat-shrinkable sheet piece 12 having wear resistance is applied to the boundary portion (rise portion) between the body sheet piece 11 and the bottom sheet piece 13, the thickness of the rise portion ( (Strength) can be contacted near the bottom circumference of the cylindrical container, causing frequent breaks in the past, especially due to contact near the bottom circumference of the cylindrical container. The cause can be effectively prevented. Moreover, the influence which heated the to-be-heated part 12a of the heat-shrinkable sheet piece 12 does not reach the trunk | drum sheet piece 11 or the bottom sheet piece 13, The inner bag 10 itself for cylindrical containers which concerns on this invention is desired. A certain strength can be obtained.

(Example 2)
Further, the present invention includes an inner bag for a cylindrical container as shown in FIG. Specifically, in the manufacturing method of the inner bag for a cylindrical container of Example 1, when the brazed sheet A is formed into a cylindrical shape, it is manufactured by welding the adhesive margin portions 11a and 12b that come on the inner surface side and the outer surface side. Can do. The cylindrical sheet B according to the second embodiment has the adhesive margins 11a and 12b welded to each other on the inner surface side and the outer surface side when the brazed sheet A is cylindrical. It will not protrude outward.

(Example 3)
Further, the present invention includes an inner bag 20 for a cylindrical container having a tapered cross-sectional view as shown in FIG. Such a cylindrical container inner bag 20 can be manufactured by cutting the body sheet piece 21 and the heat-shrinkable sheet piece 22 welded to the lower part of the body sheet piece 21 into a truncated cone shape. In the manufacturing process of Example 1 described above, no special process is required.

Example 4
Moreover, the present invention reverses the direction of the truncated cone-shaped body sheet piece 21 of the cylindrical container inner bag 20 in the third embodiment, and cuts the heat shrinkable sheet piece 22 in accordance with this direction. As shown in FIG. 7, a cylindrical container inner bag 30 having a tapered bottom in section and a small top surface can be manufactured.

  Therefore, as described above, in the cylindrical container inner bag 10 and the manufacturing method thereof according to the present invention, first, the inner circumference of the drum can to be used has a length and is welded to both ends in the length direction. A heated portion 12a is protruded downward from a lower portion of the body sheet piece 11 having the adhesive margin 11a, and a heat-shrinkable sheet piece 12 having the same length as that of the body sheet piece 11 is welded and brazed. Since the sheet A is formed, the body sheet piece 11 and the heat-shrinkable sheet 12 piece can be welded in a flat state. The adhesive margins 11a and 12b at both ends of the brazed sheet A are welded together to form the tubular sheet B, and further, the heat-shrinkable sheet piece 12 protruding from the lower portion of the body sheet piece 11 of the tubular sheet B. The heated portion 12a is heated and contracted to be bent inward, and the circular bottom sheet piece 13 is welded to the heated portion 12a of the folded heat-shrinkable sheet piece 12, so that the trunk sheet piece 11 and the bottom sheet piece The heat-shrinkable sheet piece 12 can be applied to the seal portion (rising portion) 13 and can be brought into contact with the vicinity of the circumference of the bottom of the drum can while ensuring the thickness (strength) of the rising portion. It is possible to effectively prevent pinholes and tears from occurring in the inner bag.

  Further, the heated portion 12a of the heat-shrinkable sheet piece 12 protruding from the lower portion of the body sheet piece 11 of the tubular sheet B is heated and contracted and bent inward, and the covered heat-shrinkable sheet piece 12 is covered. Since the circular bottom sheet piece 13 is welded to the heating part 12a, both the heat-shrinkable sheet piece 12 and the bottom sheet piece 13 can be welded in a flat state, and the bottom surface of the cylindrical container inner bag 10 is heated. In addition, since it is not manufactured, the manufactured inner bag 10 for a cylindrical container can make the thickness of the portion in contact with the bottom of the cylindrical container and the vicinity of the bottom circumference uniform, and the heat-shrinkable sheet piece 12 is heated. The influence of heating the part 12a does not reach the trunk sheet piece 11 and the bottom sheet piece 13, and the strength of the inner bag itself does not become a problem. And since the bottom sheet piece 13 can be manufactured as a circular shape, for example, a perfect circle, there is no space near the bottom of the cylindrical container or the bottom circumference, and it can be manufactured by folding or directly sealing. Since it does not exist, the manufacturing method of the inner bag 10 for cylindrical containers which concerns on this invention can be made easy.

  Here, in the present invention, for example, if the tubular sheet is formed while the adhesive margins at both ends of the above-described brazing sheet are stopped on the way, the body sheet piece portion where both ends are not welded It is also possible to manufacture an inner bag for a cylindrical container in which the residual amount remains. Then, in such an inner bag for a cylindrical container, if the body sheet piece portion whose both ends are not welded is tilted inward, the binding allowance of the inner bag for the cylindrical container can be secured, and both ends are not welded. The folding margin can be secured by tilting the trunk sheet piece outward. In addition, if it is formed by welding the adhesive margins at both ends of the above-mentioned brazed sheet halfway, and welding so as to squeeze the upper opening of the cylindrical sheet from the middle, a cylindrical shape with a small opening is formed. A dexterous inner bag can also be manufactured.

  As mentioned above, although several embodiment of this invention was explained in full detail, this invention is not limited to the said embodiment. The present invention can be modified in various ways without departing from the scope of the claims. Further, it goes without saying that well-known or well-known elements can be used for the elements constituting the present invention without departing from the matters described in the claims. For example, a well-known or well-known heat sealer or welding jig can be used.

Furthermore, for example, the inner bag for a cylindrical container according to the present invention is based on the premise that the lengths of the body sheet piece and the heat-shrinkable sheet piece are substantially the same when describing the above embodiment. It may be the case where the heat-shrinkable sheet piece has the inner circumference length of the drum can to be used and only the glue margins at both ends of the body sheet piece are welded to each other. If it is an inner bag, the to-be-heated part bends more smoothly by a welding jig.
Furthermore, in the above embodiment, from the viewpoint of production efficiency and the like, the process of producing the brazed sheet first and then producing the tubular sheet in the order in which it is formed is described. Even in the process of welding the adhesive margins at both ends into a tubular shape, and welding the heat-shrinkable sheet piece to the lower part of the tubular body sheet piece while protruding the heated portion downward The inner bag for cylindrical containers according to the present invention can be manufactured.

10 .. Inner bag for cylindrical container (Example 1)
11. ・ Body part sheet piece 11a ・ Glue margin part 12. ・ Heat-shrinkable sheet piece 12a ・ Heating part (part of heat-shrinkable sheet)
12b · Paste margin 12c · Welded portion 13 · · Bottom sheet piece 20 · · Inner bag for cylindrical container (Example 3)
21 .. Body sheet piece 22. Heat shrinkable sheet piece 30. Inner bag for cylindrical container (Example 4)
A ... Saddle sheet B ... Tubular sheet

Claims (2)

A heat-shrinkable sheet is welded to the lower part of a sheet that has a predetermined cylindrical container and has a glue margin that is welded to both ends in the longitudinal direction. And
The glue margins are welded to form a cylinder,
A part of the heat-shrinkable sheet protruding from the lower part of the cylindrical sheet is heated and contracted to bend inward, and a circular bottom sheet is welded to the part of the bent heat-shrinkable sheet. Become
An inner bag for a cylindrical container. The heat-shrinkable sheet has a length of an inner circumference of a predetermined cylindrical container, and a part of the heat-shrinkable sheet is protruded downward at a lower portion of a sheet having a glue margin portion welded to both ends in the length direction. Welding process;
A step of welding the glue margins to form a cylinder;
A step of heating and shrinking a part of the heat-shrinkable sheet protruding from the lower part of the cylindrical sheet to bend inward, and welding a circular bottom sheet to the part of the folded heat-shrinkable sheet When,
A method for producing an inner bag for a cylindrical container, comprising:

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