JP6013789B2 - Bubble sheet - Google Patents

Description

  The present invention relates to a bubble sheet used as a cushioning material, a heat insulating material, a curing sheet, or the like.

  Conventionally, for example, as a plastic material typified by polyethylene, a flat film (hereinafter referred to as “base film”) is bonded to one surface of a cap film on which a plurality of independent hollow protrusions are formed, There is a bubble sheet that forms a plurality of sealed bubble spaces. In addition, a base film is bonded to one surface of the cap film, and a flat film (hereinafter referred to as “liner film”) is bonded to the other surface of the cap film, so that the base film, the cap film, and the liner film are bonded. Some bubble sheets have a three-layer structure. These bubble sheets have cushioning properties, heat insulation properties, and the like, and are widely used mainly as cushioning materials (cushion materials), heat insulation materials, and curing sheets for packaging. In particular, since the three-layered bubble sheet has a flat surface, it is disposed inside the envelope in order to provide a cushioning function to the envelope or the like (see, for example, Patent Document 1).

  Such a bubble sheet is collected for recycling after use or brought into a garbage disposal facility as general garbage. However, since conventional bubble sheets have a plurality of bubble spaces, they have excellent cushioning properties. While having heat insulation properties, it has the disadvantage of being very bulky. In view of this, a bubble sheet that can easily break the bubble space and reduce its volume after use has been proposed (see, for example, Patent Document 2).

JP 2004-74725 A JP 2001-105514 A

  However, the bubble sheet that can break the bubble space described above is such that the adhesive strength between the cap film and the liner film is higher than the break strength of the cap film, and the break strength of the liner film is higher than the break strength of the cap film. In addition, it is necessary to determine the composition of each film, which takes time.

  The present invention has been made in view of such circumstances, and provides a bubble sheet that is easy to manufacture, can easily break the bubble space, and can be reduced in volume after use. With the goal.

  In order to achieve this object, the present invention provides a cap film in which a convex group consisting of a plurality of independent hollow convex portions is formed, and a surface opposite to the protruding direction of the hollow convex portion of the cap film. A base film that forms a bubble space between the hollow convex portion and a liner film that is disposed on a surface of the cap film on the protruding direction side of the hollow convex portion and is bonded to the hollow convex portion. The cap film provides a bubble sheet composed mainly of a resin having a characteristic that the breaking strength in the direction perpendicular to the stretching direction is lower than the breaking strength in the stretching direction. is there.

  Here, the cap film is generally hollow by guiding the film that is fed in a molten state from the T-die to a forming roll having a plurality of recesses, and sucking the film into the recesses. A convex part is formed. In the case of this method, the height direction of the hollow convex portion is stretched (that is, the height direction of the hollow convex portion is the stretching direction).

  Since the air bubble sheet of the present application is composed mainly of a resin having a characteristic that the breaking strength in the direction perpendicular to the stretching direction is lower than the breaking strength in the stretching direction, as described above. In the cap film formed by such a normal method, the breaking strength in the direction perpendicular to the height direction is lower than the breaking strength in the height direction (stretching direction) of the hollow convex portion. Therefore, when the liner film is peeled off from the cap film, the portion that becomes the height of the hollow convex portion is broken before the liner film is peeled off from the cap film. For this reason, the bubble space can be easily broken. Therefore, the volume can be reduced after use.

  Examples of the resin having a characteristic that the breaking strength in the direction perpendicular to the stretching direction is lower than the breaking strength in the stretching direction includes an ionomer resin.

  Moreover, the said hollow convex part group has a 1st hollow convex part and a 2nd hollow convex part, and the diameter of a 2nd hollow convex part becomes larger than the diameter of a 1st hollow convex part. Can be configured. By constituting in this way, when peeling the liner film from the cap film, if the second hollow convex part having a large diameter is broken with a finger or a cutter, the handle for peeling the liner film from the cap film. Since it is possible to make a large (a part that can be picked with a finger), in addition to the above-described advantages, the liner film can be more easily peeled off from the cap film.

  In this case, by providing a perforation in a part of the second hollow convex portion, the second hollow convex portion can be further expanded along the perforated surface. Therefore, the liner film can be more easily peeled off from the cap film.

  In addition, the bubble sheet according to the present invention is formed at a position where the distance between the adjacent hollow convex portions is longer than the distance between the other hollow convex portions and the hollow convex portions adjacent to the other hollow convex portions. You may have a hollow convex part. Here, the cap film according to the present invention has a surface in contact with the liner film of the hollow convex portion is bonded to the liner film, and the other portion is not bonded to the liner film. A portion where the distance from the adjacent hollow convex portion is long is also a portion where the liner film and the cap film are not bonded. Therefore, by comprising in this way, since the part which the liner film and the cap film have not adhere | attached can be taken widely, the handle for peeling off a liner film from a cap film can be enlarged. Therefore, in addition to the above advantages, the liner film can be more easily peeled off from the cap film.

  And the hollow convex part formed near the edge part of the said cap film may be comprised so that the distance with the said edge part may become longer than the distance with an adjacent hollow convex part. By comprising in this way, since the part which the liner film and the cap film have not adhere | attached can be formed in the edge part of a bubble sheet, the handle for peeling off a liner film from a cap film is enlarged. be able to. Therefore, in addition to the above advantages, the liner film can be more easily peeled off from the cap film.

  The present invention also provides a cap film in which a plurality of hollow convex portions are formed and a surface of the cap film opposite to the protruding direction of the hollow convex portions, and a bubble space between the hollow convex portions. Forming a base film, and a breaking sheet disposed on a surface of the base film opposite to the surface on which the cap film is disposed, wherein the breaking sheet is formed of the base film. The present invention provides a bubble sheet adhered to at least a part of a region facing the hollow convex portion.

  In the air bubble sheet having this configuration, since the breaking sheet is bonded to at least a part of the region facing the hollow convex portion of the base film, the part where the base film and the breaking sheet are not bonded is started. The break sheet can be peeled off from the base film. Moreover, since the adhesion part with the sheet | seat for a fracture | rupture of a base film peels with the said sheet | seat for a fracture | rupture, the bubble space formed between the said hollow convex part can be fractured easily. Therefore, the volume can be reduced after use.

  In the case of this air bubble sheet, the adhesive strength between the breaking sheet and the base film can be configured to be higher than the adhesive strength between the cap film and the base film. By comprising in this way, the said bubble space can be fractured | ruptured still more easily.

  The bubble sheet according to the present invention is easy to manufacture, can easily break the bubble space, and can reduce its volume after use.

It is a perspective view which shows the bubble sheet which concerns on Embodiment 1 of this invention. It is sectional drawing which shows a part of bubble sheet shown in FIG. FIG. 2 is a cross-sectional view showing a part of a state where a liner film is peeled off from the bubble sheet shown in FIG. It is a schematic diagram which shows a part of manufacturing process of the bubble sheet shown in FIG. It is a figure which expands and shows a part of manufacturing process shown in FIG. It is a schematic diagram which shows a part of manufacturing process of the bubble sheet shown in FIG. It is a top view which shows a part of bubble sheet which concerns on other embodiment of this invention. It is a partial cross section figure of the bubble sheet shown in FIG. It is a top view which shows a part of bubble sheet which concerns on other embodiment of this invention. It is sectional drawing which shows a part of bubble sheet which concerns on other embodiment of this invention. It is sectional drawing which shows the state which fractured | ruptured a part of bubble sheet which concerns on other embodiment of this invention. It is sectional drawing which shows a part of bubble sheet which concerns on other embodiment of this invention. It is sectional drawing which shows a part of bubble sheet which concerns on Embodiment 2 of this invention. It is sectional drawing which expands and shows a part of bubble sheet shown in FIG. It is sectional drawing which shows a part of the state which peeled off the film for fracture | rupture from the air bubble sheet | seat shown in FIG. It is a schematic diagram which shows a part of manufacturing process of the bubble sheet shown in FIG. (A) And (B) is a top view which shows a part of bubble sheet which concerns on other embodiment of this invention.

  Next, a bubble sheet according to an embodiment of the present invention will be described with reference to the drawings. In addition, embodiment described below is the illustration for demonstrating this invention, and this invention is not limited only to these embodiment. Therefore, the present invention can be implemented in various forms without departing from the gist thereof. Further, in each of the drawings described in each embodiment, the thickness, size, enlargement / reduction ratio, and the like of each member are not matched with actual ones for easy understanding.

(Embodiment 1)
FIG. 1 is a perspective view showing a configuration of a bubble sheet according to Embodiment 1 of the present invention, and FIG. 2 is a cross-sectional view showing a part of the bubble sheet shown in FIG.

  As shown in FIGS. 1 and 2, the bubble sheet 1 according to the first embodiment includes a cap film 12 having a convex group 11 formed of a plurality of independent hollow convex portions 11 </ b> A, and a hollow convexity of the cap film 12. The base film 13 disposed on the surface opposite to the projecting direction of the portion 11A and the surface opposite to the base film disposed surface of the cap film 12 are adhered to the hollow convex portions 11A. The liner film 14 is provided.

  The cap film 12 has a substantially circular shape in plan view, and is made of a resin (for example, an ionomer resin) having a characteristic that the breaking strength in the direction perpendicular to the stretching direction is lower than the breaking strength in the stretching direction. For example, as shown in FIG. 4, the ionomer resin film supplied by extrusion from the T die 100 is molded by a molding roll 120. Specifically, the forming roll 120 is provided with a plurality of grooves 121 for forming the hollow protrusions 11A, and the ionomer resin film is drawn into the grooves 121 by suction, whereby a plurality of hollow protrusions are formed. 11A is formed.

  Here, the ionomer resin is a polymer in which a part of hydrogen of a hydrocarbon chain is substituted with a carboxyl group, and the carboxyl group forms a salt with a metal ion Mn +, and the metal has a valence of 2 or more. If it has, it has a molecular structure in which a plurality of hydrocarbon chains are bonded through the metal ion. For example, when a film composed mainly of an ionomer resin is formed by T-die extrusion, the hydrocarbon chains are oriented by stretching and the molecules are bonded with metal ions. In this arrangement, the ionic bond between the metal and the carboxyl group is weaker than the covalent bond between carbon atoms, and since it is further weakened by stretching, it is perpendicular to the stretching direction rather than the breaking strength in the stretching direction. The direction breaking strength is lower.

  When the ionomer resin film is sucked into the groove 121 to form the hollow convex portion 11A, as shown in FIG. 5, the height direction of the hollow convex portion 11A (arrow X direction shown in FIG. 5) is the stretching direction. Therefore, in the hollow convex portion 11A, the breaking strength in the height direction is lower than the breaking strength in the direction perpendicular to the height direction.

In Embodiment 1, the cap film 12 has a thickness before forming the hollow convex portion 11A: about 30 μm, the outer diameter of the hollow convex portion 11A: about 10 mm and a height: about 4 mm, and adjacent hollow convex portions. The distance between 11A (L ₁ ) was about 2 mm. Moreover, as long as an ionomer resin is a main component, as for the cap film 12, you may add suitably other materials, for example, polyethylene.

The base film 13 is composed of, for example, a low-density polyethylene film (density: about 0.92 g / cm ³ , thickness: about 20 μm), and is supplied by extrusion from a T die 110 as shown in FIG. The low-density polyethylene film is heat-sealed to the bottom surface 15 of the cap film 12 by the pressing roll 130, and the both are bonded together to form a bubble space 16 between the hollow convex portion 11A.

The liner film 14 is composed of, for example, a low-density polyethylene film (density: about 0.92 g / cm ³ , thickness: about 20 μm), and is supplied by extrusion from a T die 140 as shown in FIG. The top surface of the hollow convex portion 11A of the cap film 12 is heat-sealed by the pressure rolls 150 and 160 with the low-density polyethylene film and the separately supplied base film 13 and the film obtained by bonding the cap film 12 together. A liner film 14 is bonded to 17 to form a space 18 with the cap film 12. The bubble sheet 1 is manufactured by the above manufacturing method.

  Next, when the used air bubble sheet 1 is collected for recycling or treated as general garbage, as shown in FIG. 3, an operation for manually peeling the liner film 14 from the cap film 12. Since the breaking strength in the height direction of the hollow convex portion 11A of the cap film 12 is weak, the hollow convex portion 11A is broken before the liner film 14 is peeled off from the cap film 12, and the volume of the bubble sheet 1 is reduced. can do. By this operation, the cap film 2 could be easily broken by hand without using a machine or a tool, and its volume could be reduced after use.

  In addition, the bubble sheet 1 which concerns on this invention is not restricted to the structure mentioned above, For example, as shown in FIG. 7, 11 A (1st hollow convex part) and a larger diameter than 11 A of hollow convex parts are shown. You may have the hollow convex part 11B (2nd hollow convex part) which has a diameter. The height of the hollow convex portion 11B is the same as the height of the hollow convex portion 11A, the formation position of the hollow convex portion 11B, the ratio between the hollow convex portion 11A and the hollow convex portion 11B, and the hollow convex portion. The outer diameter and the like of 11B can be arbitrarily set as long as the function as the bubble sheet 1 is not impaired.

  With this configuration, when the used air bubble sheet 1 is collected for recycling or is treated as general waste, the hollow convex portion 11B is broken with a finger or the like as shown in FIG. By crushing, the broken portion of the hollow convex portion 11B can be used as a handle 51 (a portion that can be picked with a finger) for peeling off the liner film 14 from the cap film 12. Thereby, the liner film 14 can be more easily peeled off from the cap film 12.

  In the case of this configuration, for example, as shown in FIG. 9, a perforation 19 is inserted so as to pass through a portion corresponding to the hollow convex portion 11B of the liner film 14, or it corresponds to the hollow convex portion 11B of the liner film 14. The perforation 19 is inserted so as to pass through both the portion to be cut and the hollow convex portion 11B, or the perforation 19 is inserted into the hollow convex portion 11B so that the perforation 19 can be further easily torn along the perforation 19 The expanded portion can be used as a handle (a portion that can be picked with a finger). Therefore, the liner film can be peeled off from the cap film more easily. Further, the perforation 19 may be formed in the width direction (direction perpendicular to the flow direction) shown in FIG. 9, and even when the perforation 19 is formed in the width direction shown in FIG. The formation position of the perforation 19 can be arbitrarily determined, for example, the perforation 19 is not formed.

Further, for example, as shown in FIG. 10, the bubble sheet 1 according to the present invention has other hollow protrusions at a position (distance L ₂ ) that is longer than the distance (L ₁ ) between the adjacent hollow protrusions 11A. The part 11A may be formed. Thus, by forming the hollow convex portion 11A at a position where the distance between the adjacent hollow convex portions 11A becomes long (L ₁ <L ₂ ), the used air bubble sheet 1 is collected for recycling, or when processing as municipal waste, as shown in FIG. 11, the distance by cutting or breaking the liner film 14 located in the portion is L _2, the cut (broken) portion, a liner film 14 can be used as a handle 51 for peeling off the cap film 12. Thereby, the liner film 14 can be more easily peeled off from the cap film 12. The distance (L ₂₎ or the like can be arbitrarily set as long as it does not impair the function of the bubble sheet 1.

Moreover, as for the bubble sheet 1 which concerns on this invention, for example, as shown in FIG. 12, the hollow convex part 11A formed in the immediate vicinity of the edge part of the cap film 12 is the distance (L ₁ ) between the adjacent hollow convex parts 11A. Instead, the distance (L ₃ ) from the end can be longer. Here, as described above, since the liner film 14 is heat-sealed to the top surface 17 of the hollow convex portion 11A of the cap film 12, the used air bubble sheet can be obtained by increasing the distance (L ₃ ). When collecting 1 for recycling or treating it as general waste, the end of the liner film 14 can be used as a handle 51 for peeling the liner film 14 from the cap film 12. Thereby, the liner film 14 can be more easily peeled off from the cap film 12.

The thickness of the cap film 12, the outer diameter and height of the hollow convex portion 11 </ b> A, the distance (L ₁ ) between the hollow convex portions 11 </ b> A adjacent to each other are within a range that does not impair the function as the bubble sheet 1. It can be set arbitrarily.

  As another embodiment, for example, as shown in FIG. 17B, the distance between the hollow convex portions 11A is larger than the distance between the normal hollow convex portions 11A (see FIG. 17A). By doing so, the length of the liner film 14 located between the hollow convex portion 11A and the hollow convex portion 11A adjacent to the hollow convex portion 11A can be secured, so that this portion is cut or broken. Thus, the cut (broken) portion can be used as a handle for peeling the liner film 14 from the cap film 12.

  Moreover, in Embodiment 1, although the case where low density polyethylene was used as the base film 13 and the liner film 14 was demonstrated, it is not restricted to this, For example, polyolefin resin, such as polypropylene resin and polyethylene resin, Or 2 or more types can be mixed and used. Examples of the polypropylene resin include a propylene homopolymer or a copolymer of propylene and another olefin. Other olefins copolymerized with propylene include α-olefins such as ethylene, butene-1, isobutylene and pentene-1, and copolymers with these other olefins include random copolymers, block Any of copolymers may be used. Examples of the polyethylene resin include high density polyethylene, low density polyethylene, linear low density polyethylene, linear ultra-low density polyethylene, and ethylene-vinyl acetate copolymer. Further, the thickness of the base film 13 and the liner film 14 can be arbitrarily set as long as the function as the bubble sheet 1 is not impaired.

(Embodiment 2)
Next, a bubble sheet according to Embodiment 2 of the present invention will be described with reference to the drawings. 13 is a cross-sectional view showing a part of the bubble sheet according to the second embodiment, FIG. 14 is an enlarged cross-sectional view showing a part of the bubble sheet shown in FIG. 13, and FIG. 15 is a bubble sheet shown in FIG. It is sectional drawing which shows a part of the state which peeled off the film for fracture | rupture from. In addition, in Embodiment 2, the same code | symbol is attached | subjected to the member similar to the bubble sheet 1 demonstrated in Embodiment 1, and the detailed description is abbreviate | omitted.

  As shown in FIGS. 13 to 15, the bubble sheet 2 according to the second embodiment includes a cap film 12 having a hollow convex portion 11 </ b> A, a base film 13 heat-sealed to the bottom surface 15 of the cap film 12, and a base film. 13 is a surface opposite to the surface to which the cap film 12 is heat-sealed, and includes a breakable film 21 adhered to a position facing the bubble space 16.

The breaking film 21 is composed of, for example, a linear low density polyethylene film (density: about 0.923 g / cm ³ , thickness: about 30 μm), and as shown in particular in FIG. A part of the region facing the space 16 is bonded to the base film 13, and other parts are not bonded. The adhesive strength between the breaking film 21 and the base film 13 is higher than the adhesive strength between the cap film 12 and the base film 13.

  The breaking film 21 is disposed on the base film 13 by, for example, the method shown in FIG. That is, using an adhesive dropping device 170 having a plurality of dropping nozzles 171 aligned with the position of the bubble space 16 of the two-layer structure film 23 composed of the base film 13 bonded to the cap film 12, along the feed line (see FIG. The position corresponding to the bubble space 16 of the two-layer structure film 23 to be conveyed is detected by a sensor (not shown), and the molten hot melt adhesive 22 dropped from the dropping nozzle 171 is introduced into the bubble space 16. Drip from the base film side to the corresponding position. Thereafter, the breaking film 21 is bonded to the base film 13 onto which the hot melt adhesive 22 has been dropped. The bubble sheet 2 is manufactured by the above method.

  In addition, the film 21 for a fracture | rupture can be comprised from resin which mixed polyolefin resin, such as a polypropylene resin and a polyethylene resin, individually or in mixture of 2 or more types. Further, the thickness of the breaking film 21 is not limited to the above-described thickness, and can be determined as desired.

  When the used air bubble sheet 2 is collected for recycling or treated as general garbage, as shown in an exaggerated manner in FIG. 14, the portion where the hollow convex portion 11A is not formed (that is, the base By cutting the portion not bonded to the film 13, the cut film 21 for the cut portion can be used as a handle 52 for peeling the base film 13 from the cap film 12. Then, by grasping the handle 52 with a finger and peeling the breaking film 21 from the base film 13, as shown in FIG. 15, the hollow convex portion 11A can be easily broken, and the volume of the bubble sheet 2 is increased. Can be small.

  In the second embodiment, the case where the cap film 12 is formed from an ionomer resin has been described. However, the present invention is not limited thereto, and the cap film 12 is made of, for example, a polypropylene resin, a polyolefin resin such as a polyethylene resin alone, Or you may form from resin which mixed 2 or more types.

  Moreover, in Embodiment 2, although the case where the method of dripping the hot-melt-adhesive 22 was used as a method of bonding the film for a fracture | rupture to the base film 13, not only this but as a method of adhere | attaching both, For example, the hot melt adhesion impregnated in the brush portion using a coating roll having a brush portion arranged in accordance with the pitch of the bubble spaces 16 of the two-layer structure film 23 conveyed along the feed line The agent may be applied to the position corresponding to the bubble space 16 from the base film side.

DESCRIPTION OF SYMBOLS 1, 2 ... Bubble sheet, 11 ... Convex part group, 11A, 11B ... Hollow convex part, 12 ... Cap film, 13 ... Base film, 14 ... Liner film, 16 ... Bubble space, 19 ... Perforation, 21 ... For break the film

Claims (3)

A cap film formed with a plurality of hollow protrusions;
A base film which is disposed on a surface opposite to the protruding direction of the hollow convex portion of the cap film and forms a bubble space between the hollow convex portion;
A breaking sheet disposed on a surface of the base film opposite to the surface on which the cap film is disposed;
Have
The rupture sheet, the hollow convex portion and Ri Contact is adhered to at least a portion of the opposing region, bubble sheet other portions are not bonded to the base film.   The bubble sheet according to claim 1, wherein an adhesive strength between the breaking sheet and the base film is higher than an adhesive strength between the cap film and the base film.   The bubble sheet according to claim 1 or 2, wherein the resin forming the cap film is an ionomer resin.

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