JP2022187114A - Production method of packaging container using laminated sheet as raw material - Google Patents

Abstract

To provide a production method of a packaging container having a storage recessed part that is formed by suspending an internal body made of a non-woven fabric sheet over an external body made of a thermoplastic resin sheet in a hammock-like manner.SOLUTION: A production method of a packaging container comprises: applying a hot-melt adhesive to a surface of a thermoplastic resin sheet or a non-woven fabric sheet, overlapping the thermoplastic resin sheet and the non-woven fabric sheet; then, peeling off the thermoplastic resin sheet of a laminated sheet from the non-woven fabric sheet to bring the same into close contact with a female mold 52 to mold an external body 111; recessing the non-woven fabric sheet of the laminated sheet with a male mold 51 to form an internal body 121; hanging the internal body 121 over the external body 111 in a hammock-like shape to form a storage recessed part; and completely adhering the thermoplastic resin sheet and the non-woven fabric sheet by pressing the laminated sheet in a portion other than the storage recessed part.SELECTED DRAWING: Figure 7

Description

The present invention relates to a method for manufacturing a packaging container using a laminated sheet obtained by laminating a thermoplastic resin sheet and a nonwoven fabric sheet as a raw material, wherein an inner body made of the nonwoven fabric sheet is provided in a recess for accommodating an object to be packaged. relates to a method of manufacturing a packaging container in which the container is stretched over an exterior body made of a thermoplastic resin sheet in the form of a hammock.

Conventionally, packaging containers for packaging soft and perishable fruits such as strawberries, loquats, peaches, etc., have been made of a laminated sheet obtained by laminating a thermoplastic resin sheet and a nonwoven fabric sheet as a material. a laminated sheet is separated into a thermoplastic resin sheet and a non-woven fabric sheet in an accommodation recess for accommodating an object to be packaged, and a hollow space is provided between the two sheets; There is one in which a storage recess is formed by spanning it in a hammock shape. In a packaging container provided with such an accommodating concave portion, the items to be packaged are accommodated on an inner body made of a non-woven fabric sheet having excellent air permeability, flexibility and elasticity, and are relatively hard. Since it is held in a state where it does not come into contact with the exterior body made of a plastic resin sheet, even fruits such as strawberries, loquats, and peaches, which have soft surfaces and are easily damaged, can be delicately packaged.

As a method for manufacturing such a packaging container, for example, Japanese Utility Model Laid-Open No. 61-74514 discloses that a thermoplastic resin sheet and a non-woven fabric sheet are separably superimposed, heated to be plasticized, and then The non-woven fabric sheet is fed between a convex mold and a concave mold configured to have a predetermined space in a clamped state, and the molds are clamped to form a non-woven fabric sheet recessedly. A manufacturing method has been proposed in which a thermoplastic resin sheet is separated from a non-woven fabric sheet by pulling and made to conform to a concave mold. Regarding the superposition of the thermoplastic resin sheet and the non-woven fabric sheet, (a) the non-woven fabric sheet is simply placed along the thermoplastic resin sheet without being joined, and (b) the non-woven fabric sheet is heated with a heating roll or the like. It has been proposed to lightly heat-seal the sheet or (c) bond only the portion other than the portion where the accommodation recess is formed with an adhesive or other means.

However, there are the following problems in superimposing the thermoplastic resin sheet and the nonwoven fabric sheet in this manufacturing method.
(a) When the non-woven fabric sheet was simply laid along the thermoplastic resin sheet without being bonded, the non-woven fabric sheet was pulled and stretched when the non-woven fabric sheet was superimposed on the thermoplastic resin sheet and wound with the take-up roller. This may affect the stretchability of the non-woven fabric sheet in the storage recess after molding.
(b) When the non-woven fabric sheet is lightly heat-sealed to the thermoplastic resin sheet with a heating roll or the like, the non-woven fabric sheet and the thermoplastic resin sheet are heat-sealed, so the releasability is poor. There is a possibility that the thermoplastic resin sheet cannot be properly separated from the nonwoven fabric sheet when forming the recesses. In addition, after the thermoplastic resin sheet is separated from the nonwoven fabric sheet, part of the heat-sealed thermoplastic resin sheet remains on the nonwoven fabric sheet side, which adversely affects the breathability, flexibility, and stretchability of the nonwoven fabric sheet. There is also a problem.
(c) When only the parts other than the part where the accommodation recess is formed are joined by an adhesive or other means, when the adhesive is applied, the adhesive is sure to adhere only to the parts other than the part where the accommodation recess is formed. Strict application control must be performed so that the adhesive is not applied to the portion where the adhesive is applied and the accommodation recess is formed.

Further, Japanese Patent Laid-Open No. 2010-260308 also discloses that a laminated sheet formed by laminating a synthetic resin sheet and a nonwoven fabric sheet is used as a material, and in a storage recess in which an object to be packaged is accommodated, the laminated sheet is used as the synthetic resin sheet and the nonwoven fabric sheet. A method for manufacturing a packaging container is disclosed in which a hollow portion is provided between the two sheets, and an interior body made of a nonwoven fabric sheet is hung over an exterior body made of a synthetic resin sheet in a hammock-like manner to form a storage recess. there is In this packaging container manufacturing method, the synthetic resin sheet and the non-woven fabric sheet are laminated together in such a manner that the synthetic resin sheet has a peripheral portion corresponding to a size for processing the non-woven fabric sheet into a single container. It has been proposed to form a laminated sheet by strongly adhering at a portion where the sheet is not formed, and adhering at a portion inside the peripheral portion in a state where the adhesive strength is weaker than that of the peripheral portion.

According to the lamination of the synthetic resin sheet and the non-woven fabric sheet in this manufacturing method, the synthetic resin sheet and the non-woven fabric sheet are firmly adhered in the peripheral portion corresponding to the size to be processed as one container, and the peripheral portion is Since the inside is attached with a weaker adhesive force than the peripheral portion, when the synthetic resin sheet and the non-woven fabric sheet are adhered to form a laminated sheet, the portion where the storage recess is formed and the other portion It is not necessary to finely control the coating so that only the parts other than the part where the storage recess is formed are firmly attached. There is a problem that the coating must be managed separately for the peripheral portion that is adhered to the surface and the inner portion that is weakly adhered.

Japanese Utility Model Laid-Open No. 61-74514

JP 2010-260308 A

In the present invention, a laminated sheet made of a thermoplastic resin sheet and a nonwoven fabric sheet is used as a raw material, and the laminated sheet is separated into the thermoplastic resin sheet and the nonwoven fabric sheet in an accommodation recess in which an object to be packaged is accommodated, and the thermoplastic resin sheet is separated from the nonwoven fabric sheet. In a method for manufacturing a packaging container in which an interior body made of a non-woven fabric sheet is hung over an exterior body made of a non-woven fabric sheet in a hammock-like manner to form a storage recess, when forming a laminated sheet, a section with a strong adhesive strength and a section with a strong adhesive strength and a section with a low adhesive strength are formed. A thermoplastic resin sheet and a non-woven fabric sheet can be easily separated from each other in a portion where a recess for storage is formed when a packaging container is molded without managing adhesive coating separately from a weak section, and the recess for storage can be easily separated. An object of the present invention is to obtain a method for manufacturing a packaging container capable of completely adhering a thermoplastic resin sheet and a non-woven fabric sheet in a portion other than the portion where a is formed.

In the method for manufacturing a packaging container of the present invention, a hot-melt adhesive is applied to the surface of a thermoplastic resin sheet or nonwoven fabric sheet, the thermoplastic resin sheet and the nonwoven fabric sheet are overlapped, and then pressed in an unheated state. By doing so, a laminated sheet is formed by temporarily bonding the thermoplastic resin sheet and the nonwoven fabric sheet, and between the male mold and the female mold configured so that a predetermined space is formed inside when the mold is closed, In a heated state, the laminated sheet is fed with the nonwoven fabric sheet side facing the male die and the thermoplastic resin sheet side facing the female die, and the male die and the female die are clamped to form the female die. By vacuum suction from the suction hole provided in the laminated sheet, the thermoplastic resin sheet of the laminated sheet is peeled from the nonwoven fabric sheet and brought into close contact with the female mold to form an outer body, while the nonwoven fabric sheet of the laminated sheet is recessed with the male mold to form an interior body, thereby forming a storage recess in which the interior body spans over the exterior body in a hammock-like manner, and presses the laminated sheet in a portion other than the storage recess. and the thermoplastic resin sheet and the non-woven fabric sheet are completely adhered.

Application of the hot melt adhesive to the surface of the thermoplastic resin sheet or nonwoven fabric sheet may be by a known coating method using a roll coater, dispenser, etc., but it should be by spray coating, and the hot melt adhesive applied It is preferable that the adhesive layer by is provided with countless voids (Claim 2). The adhesive layer with numerous voids can be obtained, for example, by spraying the hot-melt adhesive in various patterns such as spider web, fibrous, spiral, wavy, and striped. .

In the present invention, "pressing in a non-heated state" refers to pressing at a temperature at which the applied hot-melt adhesive does not melt, and not only pressing without applying heat, but also pressing while cooling. It is a concept that also includes

According to this invention, a hot-melt adhesive is applied to the surface of a thermoplastic resin sheet or a non-woven fabric sheet, the thermoplastic resin sheet and the non-woven fabric sheet are overlapped, and then pressed in an unheated state. Since the packaging container is formed by using the laminated sheet formed by temporarily bonding the plastic resin sheet and the nonwoven fabric sheet, the thermoplastic resin sheet and the nonwoven fabric are formed in the portion where the accommodation recess is formed when the packaging container is molded. The sheets can be easily separated from each other, and the thermoplastic resin sheet and the nonwoven fabric sheet can be completely adhered to each other in the portions other than the portions where the accommodating recesses are formed, thereby manufacturing the packaging container. That is, in a laminated sheet in which a thermoplastic resin sheet and a nonwoven fabric sheet are temporarily bonded via a hot-melt adhesive, the thermoplastic resin sheet and the nonwoven fabric sheet are not completely bonded. When a force is applied in the peeling direction, the two sheets can be easily peeled off, and when the two sheets are heated and pressed together, the two sheets can be strongly adhered together by the melted hot-melt adhesive. As a result, the thermoplastic resin sheet and the non-woven fabric sheet can be easily separated in the portion where the accommodation recess is formed when molding the packaging container, and the thermoplastic resin sheet and the non-woven fabric sheet can be easily separated in the portion other than the portion where the accommodation recess is formed. and can be completely glued. For this reason, as in the conventional method, when forming a laminated sheet, it is divided into a section with weak adhesion (the part where the accommodation recess is formed) and a section with strong adhesion (the part other than the part where the accommodation recess is formed). There is no need to carry out troublesome coating management such as applying adhesive by hand.

According to the second aspect of the invention, the hot-melt adhesive is applied to the surface of the thermoplastic resin sheet or the non-woven fabric sheet by spray coating, and the hot-melt adhesive layer applied has numerous voids. Therefore, the adhesive strength in the temporarily bonded state is further weakened, and the thermoplastic resin sheet and the nonwoven fabric sheet can be more easily separated. In addition, even if the hot-melt adhesive layer remains attached to the inner body side made of the non-woven fabric sheet after the storage recess is formed, the hot-melt adhesive layer has countless voids, so the air permeability of the non-woven fabric sheet is improved. , There is no risk of adversely affecting flexibility and stretchability. Furthermore, by applying the hot-melt adhesive by spraying, the amount of hot-melt adhesive used can be suppressed to a small amount.

Figures for explaining the outline of the manufacturing method of the packaging container of the present invention Diagram showing the outline of the laminated sheet forming process Diagram showing the outline of the laminated sheet Similarly, a diagram explaining the heating process of the laminated sheet Schematic diagram of the mold used in the packaging container molding process Similarly, a diagram explaining the feeding process to the mold Similarly, a diagram explaining the clamping of the mold and the vacuum forming process Diagram showing the outline of the completed packaging container

As shown in FIG. 1, the method for manufacturing a packaging container of the present invention can be roughly divided into a laminated sheet forming step for forming a laminated sheet used as a material for the packaging container, and a laminated sheet forming step formed in this laminated sheet forming step. and a container forming step of forming a packaging container using the laminated sheet.

<Laminated sheet forming process>
FIG. 2 is a diagram showing an outline of the laminated sheet forming process.
In the step of forming the laminated sheet, first, a melted PP (polypropylene) hot melt adhesive B is applied to the entire surface of a thermoplastic resin sheet 11 made of A-PET (amorphous polyethylene terephthalate) having a thickness of 0.3 mm. is uniformly sprayed in the form of a spider web by spray 2. The amount of hot-melt adhesive B applied at this time is about 5 g/m ² .
Next, the thermoplastic resin sheet 11 coated with the hot-melt adhesive B is overlaid with a PET (polyethylene terephthalate) nonwoven fabric sheet 12 (basis weight of about 100 g/m ² ) manufactured by a needle punching method. The thermoplastic resin sheet 11 and the nonwoven fabric sheet 12 are joined together by pinching and pressing them from both sides using the heating rollers 3 . At this time, the hot-melt adhesive B is in a semi-cured state due to a decrease in temperature during the time from being sprayed onto the surface of the thermoplastic resin sheet 11 by the spray 2 to being pressed by the two non-heating rollers 3. Therefore, the laminated sheet 1 is formed in which the thermoplastic resin sheet 11 and the non-woven fabric sheet 12 are temporarily adhered with such an adhesive strength that they can be easily separated.
When this laminated sheet 1 is rolled up by a roll-up roller or the like to form a raw fabric, the thermoplastic resin sheet 11 and the nonwoven fabric sheet 12 are rolled up together in a temporarily bonded state, and only the nonwoven fabric sheet 12 is pulled and stretched. There is no possibility that the laminated sheet 1 will be formed in a state where it has been tucked away.

FIG. 3 is a diagram showing an outline of the laminated sheet 1 formed by the method described above. Since the laminated sheet 1 is formed by being pressed in an unheated state, the hot-melt adhesive B interposed between the thermoplastic resin sheet 11 and the nonwoven fabric sheet 12 does not exert its original adhesive strength. First, the thermoplastic resin sheet 11 and the non-woven fabric sheet 12 are joined with a weak adhesive strength. Therefore, the thermoplastic resin sheet 11 and the nonwoven fabric sheet 12 are easily separated from each other when a force is applied to separate the thermoplastic resin sheet 11 and the nonwoven fabric sheet 12 in the direction perpendicular to the sheet surfaces. Further, since the hot melt adhesive B is not melted when pressed by the non-heating roller 3, the state (spider web shape) when applied to the surface of the thermoplastic resin sheet 11 is maintained even after pressing.

In this embodiment, the laminated sheet 1 is formed by using the thermoplastic resin sheet 11 as the base material, applying the hot-melt adhesive B to the surface of the base material, and superimposing the nonwoven fabric sheet 12 thereon. The laminated sheet 1 can also be formed by using a base material, applying a hot-melt adhesive B to the surface of the base material, and superimposing the thermoplastic resin sheet 11 thereon. In this embodiment, the hot melt adhesive B is described as being sprayed in a spider web pattern, but it can also be sprayed in various patterns such as fibrous, spiral, wavy, and striped patterns. be. The point is that the hot-melt adhesive layer formed by spray coating is not a solid adhesive layer but an adhesive layer with numerous voids.

In addition to A-PET (amorphous polyethylene terephthalate), thermoplastic resin sheet materials include OPS (biaxially oriented polystyrene), PS (polystyrene), PSP (expanded polystyrene), PP (polypropylene), and PLA (polystyrene). lactic acid) and the like can also be used.

<Packaging container molding process>
4 to 8 are diagrams for explaining the molding process of the packaging container 10 using the laminated sheet 1. FIG.
In the molding process of the packaging container, first, the laminated sheet 1 in which the thermoplastic resin sheet 11 and the non-woven fabric sheet 12 are temporarily bonded with the hot-melt adhesive B is heated by the heater 4 to be softened ( Figure 4).
Next, the laminated sheet 1 in a heated state is fed to the mold 5 with the nonwoven fabric sheet 12 side facing the male mold 51 and the thermoplastic resin sheet 11 side facing the female mold 52 (FIG. 6). After tightening, vacuum suction is performed from a suction hole 52h provided in the female die 52 (Fig. 7). The male mold 51 and the female mold 52 are formed so that the convex shape of the male mold 51 is smaller than the concave shape of the female mold 52 so that the space S is formed when the molds are clamped (FIG. 5). Then, when vacuum suction is applied from the suction holes 52h of the female die 52, the thermoplastic resin sheet 11 of the laminated sheet 1 is peeled off from the nonwoven fabric sheet 12 and closely adhered to the female die 52 to mold the exterior body 111, and the nonwoven fabric sheet 12 is formed. is recessed by the male die 51 to form the interior body 121, thereby forming the housing recess 101 in which the interior body 121 is hung over the exterior body 111 in a hammock-like manner. In addition, the laminated sheet 1 is pressed by the male mold 51 and the female mold 52 in the portion 102 other than the accommodation recess. The original adhesive strength of the adhesive B is exerted and the thermoplastic resin sheet 11 and the nonwoven fabric sheet 12 are completely bonded.
After cooling in this state, the packaging container 10 shown in FIG. 8 can be obtained by releasing from the mold.

In the molded packaging container 10, the laminated sheet 1 is separated into the thermoplastic resin sheet 11 and the non-woven fabric sheet 12 in the accommodation recess 101, and the inner body 121 made of the non-woven fabric sheet 12 is replaced by the outer body made of the thermoplastic resin sheet 11. A hollow portion is formed between the inner body 121 and the outer body 111 so as to be stretched over the inner body 121 and the outer body 111 in a hammock-like manner. On the other hand, the thermoplastic resin sheet 11 and the non-woven fabric sheet 12 are completely bonded with the hot-melt adhesive B in the portion 102 other than the accommodation recess. Therefore, when an object to be packaged is accommodated on the interior body 121 of the accommodation recess 101, the part 102 other than the accommodation recess where the thermoplastic resin sheet 11 and the non-woven fabric sheet 12 are completely bonded is used as a fulcrum, and the package is placed inside the exterior body 111. The inner body 121 expands and contracts appropriately according to the weight of the package, so that the package is held in a floating state. The inner body 121 is composed of the non-woven fabric sheet 12 and has flexibility, stretchability, and air permeability. In the case that is a perishable product such as fruit, it also contributes to maintaining its freshness.

In addition, the hot melt adhesive B in the accommodation recess 101 adheres as a residue to either or both of the thermoplastic resin sheet 11 side (exterior body 111 side) and the nonwoven fabric sheet 12 side (inner body 121 side). The hot-melt adhesive B is applied in a spider web shape, and the fibers are entangled like a nonwoven fabric to form countless voids. Even in such a case, the flexibility, stretchability, and air permeability of the nonwoven fabric sheet 12 are not adversely affected.

According to the above-described manufacturing method, when forming the laminated sheet 1 used as the material for the packaging container 10, a section with weak adhesion (the portion where the accommodation recess 101 is formed) and a section with strong adhesion (the accommodation recess) When molding the packaging container 10, lamination can be performed at the portion where the accommodation recess 101 is formed without performing troublesome coating management such as separately applying the adhesive to the portion 102) other than the portion to be formed. The sheet 1 can be easily separated into the thermoplastic resin sheet 11 and the non-woven fabric sheet 12 to mold the exterior body 111 and the interior body 121, and the thermoplastic resin sheet 102 other than the part where the accommodation recess is formed is thermoplastic. The packaging container 10 can be formed by completely bonding the resin sheet 11 and the nonwoven fabric sheet 12 together.

Further, the hot melt adhesive B is sprayed and applied in a spider web shape, and the hot melt adhesive layer in the laminated sheet 1 is in a state in which fine fibers are entangled like a nonwoven fabric and countless voids are formed. , the thermoplastic resin sheet 11 and the non-woven fabric sheet 12 are more easily separated, and after the accommodation recess 101 is formed, the hot-melt adhesive B is left behind on the inner body 121 side made of the non-woven fabric sheet 12. Even in such a case, the nonwoven fabric sheet 12 does not have an adverse effect on its breathability, flexibility and stretchability.

As described above, the embodiments have been described using simplified schematic diagrams. Various shapes are conceivable as the shape of the packaging container, and the shape is not limited to the shapes described above.

The present invention relates to a method for manufacturing a packaging container using a laminated sheet obtained by laminating a thermoplastic resin sheet and a nonwoven fabric sheet as a raw material, wherein an inner body made of the nonwoven fabric sheet is provided in a recess for accommodating an object to be packaged. relates to a method of manufacturing a packaging container that is stretched over an exterior body made of a thermoplastic resin sheet in the form of a hammock, and has industrial applicability.

1 Laminated sheet 11 Thermoplastic resin sheet 111 Exterior body 12 Non-woven fabric sheet 121 Interior body 2 Spray 3 Non-heated roller 4 Heater 5 Mold 51 Male mold 52 Female mold 52h Suction hole 10 Packaging container 101 Concave portion 102 Portion other than concave portion B Hot-melt adhesive S Space

Claims (2)

A hot-melt adhesive is applied to the surface of a thermoplastic resin sheet or a nonwoven fabric sheet, the thermoplastic resin sheet and the nonwoven fabric sheet are overlapped, and then pressed in a non-heated state to bond the thermoplastic resin sheet and the nonwoven fabric. Temporarily bonding the sheet to form a laminated sheet,
Between a male mold and a female mold configured to form a predetermined space inside when the molds are closed, the nonwoven fabric sheet side is placed on the male mold side and the thermoplastic resin sheet side is placed on the male mold side while the laminated sheet is heated. feeding on the female side;
By clamping the male mold and the female mold and vacuum sucking from the suction holes provided in the female mold, the thermoplastic resin sheet of the laminated sheet is peeled off from the nonwoven fabric sheet and closely attached to the female mold. The non-woven fabric sheet of the laminated sheet is recessed by the male die to form an interior body while forming the exterior body by pressing the outer body, and the interior body is suspended over the exterior body in the form of a hammock to form a housing recess. While forming, the thermoplastic resin sheet and the nonwoven fabric sheet are completely adhered by pressing the laminated sheet in a portion other than the accommodation recess,
A method for manufacturing a packaging container. 2. The method of manufacturing a packaging container according to claim 1, wherein the hot-melt adhesive is applied by spray coating, and the adhesive layer of the applied hot-melt adhesive has numerous voids.

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