JP4974786B2 - In-mold label container - Google Patents

Description

  The present invention has an in-mold molding method in which a label is adhered or welded to the outer surface of a container body having a bottomed cylindrical shape having an opening, for example, as a container for storing food such as yogurt, pudding, coffee, and soft drinks. The present invention relates to an in-mold label container used.

An in-mold label container is molded by an in-mold molding method in which a synthetic resin is injected into a mold to mold the container body, and at the same time, the label is adhered or welded to the surface of the container body in the mold. Container. Conventionally, for example, a container disclosed in Patent Document 1 is known as such an in-mold label container. The in-mold label container of Patent Document 1 is an in-mold molded polyethylene resin injection-molded container, and a label is welded to the outer peripheral surface of the side wall and the outer surface of the bottom wall of the container. This label is characterized in that the innermost layer and the outermost layer are made of the same layer, and at least a resin film layer and a barrier base material layer are laminated between the layers. This in-mold label container has a light-shielding property and a barrier property against oxygen, water vapor and the like, and is configured to meet the hygiene standards of the ministerial ordinance concerning the component standards of milk and dairy products.
JP 11-28741 A

  By the way, petroleum, which is a raw material for synthetic resins, is a limited resource that will eventually be depleted, so it needs to be used effectively. In addition, carbon dioxide, which is emitted due to oil consumption, is a cause of global warming, so it must be reduced. In the in-mold label container according to the present invention, it is required to reduce the weight of the container body and reduce the amount of resin to be used from the viewpoints of reducing the product cost and reducing the volume at the time of disposal. One way to reduce the weight of the container body is to reduce the thickness of the container body to make it thinner. However, the currently manufactured containers have been thinned to a thickness that can ensure the strength enough to withstand the usage environment. It is very difficult from the aspect.

  The present invention has been made in view of such conventional circumstances, and an object of the present invention is to provide an in-mold label container that is strong enough to withstand the use environment even when the container body is thinned. There is.

In order to achieve the above object, an in-mold label container according to claim 1 is formed of a synthetic resin, has a cylindrical side wall and a bottom wall, has a bottomed cylindrical container body having an opening, and the container. An in-mold label container having a label adhered or welded to the outer surface of the main body, wherein a plurality of vertical ribs projecting inward of the container main body and extending in the vertical direction are formed on the inner peripheral surface of the side wall. The side wall has a covering portion covered with a label and a longitudinally extending gap formed between a side edge of the label and a side edge of the label, and one of the vertical ribs Is provided inside the gap in the side wall .

  According to the said structure, the intensity | strength in the vertical direction of an in-mold label container can be improved especially. Further, the vertical rib having a thickness larger than that of the other part of the side wall functions as a resin flow path when the container is molded in-mold. That is, the resin is filled so that the resin overflows from the region gradually spreads over the entire side wall while flowing through the thick region for forming the vertical ribs first. This makes it possible to fill the resin with a small injection pressure as compared with the case where the side walls are simply made thin without providing the vertical ribs on the side walls. When high pressure is applied to the resin during in-mold molding, the molecular chains of the resin are oriented in the flow direction, that is, in the longitudinal direction. According to this orientation, the strength in the intermolecular chain direction is weakened, and the strength of the container is reduced. Causes a drop. However, according to the above configuration, since it is possible to fill the resin with a small injection pressure, the impact strength of the container is improved by relaxing the orientation of the molecular chains of the resin and disturbing the alignment of the molecular chains. Can do. Therefore, according to the above configuration, the strength sufficient to withstand the use environment is ensured even when the container body is thinned. Of course, the structure of the plurality of vertical ribs provided on the side wall ensures a predetermined strength as a container and realizes weight reduction of the container. Moreover, since the outer peripheral surface of the side wall is a curved surface without irregularities as usual, it does not affect the label adhesion or welding process to the outer peripheral surface of the side wall and the design of the container.

In addition, when the resin injected into the mold is rapidly cooled during the molding of the in-mold label container, the molecular chains of the resin are oriented, causing a reduction in the impact strength of the container. Since the cooling of the resin is performed through the mold, on the side wall of the container, when comparing the cover portion where the label is interposed between the mold and the resin and the gap portion where the label is not interposed, the gap portion is formed between the mold and the resin. Are in direct contact with each other, the cooling efficiency is high, and the molecular chains are easily oriented accordingly. However, according to the said structure, the vertical rib is provided inside the clearance gap part in a container main body, and the cooling efficiency of resin is made small by making a clearance gap thick. Thereby, the orientation of the molecular chain in the gap is relaxed and the impact strength reduction of the container is suppressed.

The in-mold label container according to claim 2 is characterized in that, in the invention according to claim 1 , the vertical rib provided inside the gap is formed wider than other vertical ribs. To do. According to the above configuration, when the label is adhered or welded in the mold, the vertical rib can be positioned inside the gap even if the label is displaced in the circumferential direction of the container.

In-mold label container according to claim 3, in the invention described in claim 1 or claim 2, wherein the bottom wall, that the periphery formed by forming a bulge surface that bulges toward the lower direction Features. According to the above configuration, since the flow resistance of the resin flowing between the bottom wall and the side wall is suppressed during in-mold molding, the container can be molded with a small injection pressure. Thereby, the orientation of the molecular chain is relaxed and the impact strength reduction of the container can be suppressed.

The in-mold label container according to claim 4 is the invention described in any one of claims 1 to 3 , wherein the bottom wall is provided with an annular rib projecting downward at a central portion thereof. Features.

  According to the said structure, the intensity | strength of a bottom wall can be improved especially. Also, when molding an in-mold label container, it is common to position a gate for injecting resin at the center of the outer surface of the bottom wall of the container, and molecular chains are easily oriented on the bottom wall due to residual stress of the resin. ing. However, according to the above configuration, since the residual stress is dispersed by the annular rib, the orientation of the molecular chain is relaxed, and the impact strength of the container can be prevented from being lowered.

  According to the in-mold label container of the present invention, the strength sufficient to withstand the use environment is ensured even when the container body is thinned.

  Hereinafter, the in-mold label container 1 which actualized this embodiment is demonstrated based on FIGS. 1-4. As shown in FIG. 1, an in-mold label container 1 is labeled on the outer surface of a container body 2 formed by a disk-shaped bottom wall 10 and a cylindrical side wall 20 standing on the outer periphery of the bottom wall 10. 3 is adhered or welded (hereinafter simply referred to as adhesion).

  The container body 2 of the present embodiment is molded by in-mold molding (hereinafter simply referred to as molding) using a synthetic resin such as polyethylene, polyethylene terephthalate, polystyrene, or polypropylene as a material. As shown in FIG.1 and FIG.3, the side wall 20 has comprised the taper shape which expands from the lower end side toward an upper end side. And as shown in FIG. 3, the side wall 20 is located on the trunk | drum 20B located in the base 20A which is located in the lower end and to which the bottom wall 10 is connected, the base 20B located on the base 20A, and the trunk | drum 20B. And an opening 20C having an opening. In the base portion 20A, a leg portion 21 formed thicker than the other wall surface of the base portion 20A is provided on the lower end side of the connection portion with the bottom wall 10. Further, at the upper end of the inner peripheral surface of the base portion 20A, a horizontal rib 22 having a triangular cross section with a horizontal surface on the upper side is provided so as to protrude over the entire periphery of the base portion 20A. The lateral rib 22 not only functions as a reinforcing portion of the base portion 20A, but also when the plurality of in-mold label containers 1 are stacked, the leg portions 21 of the in-mold label containers 1 stacked above are received. It functions as a part. Therefore, it is easy to separate the in-mold label container 1 from the state in which the plurality of in-mold label containers 1 are stacked. In the present embodiment, the thickness of the wall surface of the base portion 20A is set to 0.7 mm, and the thickness of the leg portion 21 is set to 0.85 mm.

  As shown in FIG. 3, the body portion 20 </ b> B is formed so that the wall thickness thereof is smaller than the wall thickness of the base portion 20 </ b> A. An inclined surface 23 is provided at the upper end on the inner peripheral surface side so that the wall thickness gradually increases toward the opening 20C. As shown in FIGS. 2 and 3, eight vertical ribs 24 extending in the vertical direction, that is, in the height direction of the side wall 20 are projected from the inner peripheral surface of the body portion 20 </ b> B. The vertical ribs 24 are provided at equal intervals in the circumferential direction of the body portion 20B, and the inclined surface 23 is formed in such a shape that its width tapers toward the opening 20C side. In addition, one of the eight vertical ribs 24 has a width wider than that of the other vertical ribs 24a (see FIG. 2). In the present embodiment, the wall thickness of the body portion 20B is 0.45 mm, and the protruding height of the vertical ribs 24 is 0.25 mm. That is, the vertical rib 24 is formed so that the sum of the protruding height and the wall thickness of the body portion 20B is equal to the wall thickness of the base portion 20A.

  As shown in FIGS. 3 and 4, a flange 25 extending horizontally toward the outside of the side wall 20 along the opening edge is provided at the upper end of the opening 20 </ b> C. Further, the wall thickness of the opening 20C is formed to be the same as the wall thickness of the base 20A.

  Next, the bottom wall 10 will be described. As shown in FIGS. 3 and 4, the bottom wall 10 has a circular plate shape, and a peripheral portion 11 that forms a bulging surface that bulges downward from the side wall 20 toward the center of the in-mold label container 1. And a central portion 12 located inside the peripheral edge portion 11.

  The peripheral edge 11 is a connecting portion with the side wall 20, and the bulging surface formed by the peripheral edge 11 is formed such that the inner angle Θ formed by the side wall 20 and the peripheral edge 11 is 100 degrees or more and less than 180 degrees. Thereby, for example, compared with the case where the inner angle Θ is 90 degrees, the flow resistance of the resin flowing between the bottom wall 10 and the side wall 20 when the container body 2 is molded is suppressed, and the fluidity of the resin is improved. The container body 2 of the present embodiment has an L / t (resin flow distance / average container thickness) of 200 or more when molded using polypropylene, and the in-mold label container 1 of the present embodiment flows resin. It is configured in an easy shape. The conventional in-mold label container has an L / t of about 160 when molded using polypropylene.

  As shown in FIG. 3, the central portion 12 is formed in a spherical shape that bulges upward toward the center of the bottom wall 10. In this way, by causing the central portion 12 to bulge upward, it is possible to suppress expansion of the container due to an increase in internal pressure that occurs when contents are put into the in-mold label container 1. In the present embodiment, the in-mold label container 1 is molded in a state where the gate hole is arranged at a position corresponding to the center of the outer surface of the center portion 12 of the bottom wall 10. A gate hole mark 14 is formed. As shown in FIGS. 3 and 4, two annular ribs 15 projecting downward are provided concentrically on the outer surface of the central portion 12, and a substantially hemisphere bulging upward at the center of the inner surface of the central portion 12. A thick-walled portion 13 is provided. Each of the annular ribs 15 and the thick portion 13 is formed so as to center on the gate hole mark 14.

In the present embodiment, the thickness of the peripheral portion 11 and the central portion 12 is 0.95 mm, and the thickness of the top portion of the thick portion 13 is 1.35 mm.
Next, the label 3 adhered to the outer surface of the container body 2 will be described. In the present embodiment, the label 3 is a single sheet material having a belt-like shape, and is in close contact with the outer peripheral surface of the side wall 20 so that the side edges thereof face each other. The horizontal length of the label 3, that is, the circumferential length of the side wall 20 is set to be smaller than the outer periphery of the side wall 20, and when the label 3 is attached to the container body 2, A gap S extending in the vertical direction with a constant width is formed between the opposing side edges (see FIGS. 1 and 2). Therefore, as shown in FIG. 2, the side wall 20 has a covering portion 20 </ b> D (outside the broken line in FIG. 2) covered with the label 3 and a gap portion 20 </ b> E (a broken line in FIG. 2) where the gap S is located. Inside). The wide vertical ribs 24a are provided on the inner peripheral surface side of the gap 20E.

  Further, as shown in FIG. 3, the length of the label 3 in the vertical direction is set to a length that covers a part of the flange 25 and can cover most of the legs 21. By setting the dimensions of the label 3 in this way, it is difficult for the label 3 to overlap and to be wrinkled at the side edges that cause the label 3 to peel off.

Next, operational effects in the present embodiment will be described below.
(1) In the present embodiment, on the inner peripheral surface of the body portion 20B of the side wall 20, a vertical rib 24 that protrudes inward of the container body 2 and extends in the vertical direction is provided. Thereby, the intensity | strength in the vertical direction of the in-mold label container 1 can be improved. Further, when the container main body 2 is molded, the longitudinal ribs 24 formed thicker than the wall surface of the trunk portion 20B function as a resin flow path. Specifically, at the time of molding, the resin first fills the vertical ribs 24 and the resin overflowing from the vertical ribs 24 gradually spreads over the entire side wall 20. Therefore, as compared with a configuration in which the vertical ribs 24 are not provided, the resin easily flows during molding, and the resin can be filled with a small injection pressure. Therefore, since the injection pressure can be suppressed, the orientation of the molecular chain of the resin due to the high pressure acting on the resin is relaxed, and the impact strength of the container body 2 can be improved. Therefore, even if the container main body 2, particularly the body portion 20 </ b> B, is thinned, a decrease in strength associated therewith can be suppressed.

  Further, by suppressing the injection pressure, it is possible to reduce the size of the mold used at the time of molding, and the manufacturing cost of the in-mold label container 1 can be suppressed. In addition, in this embodiment, since the vertical rib 24 is provided in the inner peripheral surface side of the trunk | drum 20B, it influences the contact | adherence process of the label 3 with respect to the outer peripheral surface of the side wall 20, and the designability of the in-mold label container 1. There is nothing.

  (2) In this embodiment, in the side wall 20, one of the vertical ribs 24 is provided on the inner peripheral surface side of the gap 20E. Therefore, the gap 20E, which is a part where the gap S is located, is thick, and the resin cooling efficiency in the gap 20E is reduced. Therefore, the molecular chain orientation in the gap 20E is relaxed, and the impact strength reduction of the container can be suppressed.

  (3) In the present embodiment, the vertical ribs 24 a provided on the inner peripheral surface side of the gap portion 20 </ b> E are formed wider than the other vertical ribs 24. Thus, when the label 3 is brought into close contact with the inside of the mold at the time of molding, even if the positional deviation of the label 3 occurs in the circumferential direction of the container body 2, the vertical rib 24a is positioned on the inner peripheral surface of the gap 20E. Can be made.

  (4) In this embodiment, the bottom wall 10 is provided with a peripheral edge portion 11 that forms a bulging surface that bulges downward. Thereby, at the time of molding, the flow resistance of the resin flowing between the bottom wall 10 and the side wall 20 is suppressed, so that the resin easily flows and the in-mold label container 1 can be molded with a small injection pressure. Become. Therefore, the orientation of the molecular chain is relaxed and the impact strength reduction of the in-mold label container 1 can be suppressed.

  (5) In the present embodiment, an annular rib 15 protruding downward is provided at the central portion 12 of the bottom wall 10. Thereby, especially the intensity | strength of the bottom wall 10 can be improved. Further, since the annular rib 15 is formed so as to have the gate hole mark 14 as the center, it is possible to disperse residual stress that easily acts in the vicinity of the gate hole during molding. Therefore, the orientation of the molecular chain of the resin due to the residual stress is relaxed and the impact strength of the in-mold label container 1 is improved.

  (6) As described in the above (1) to (5), the in-mold label container 1 of the present embodiment is particularly suitable for relaxing the alignment of the molecular chains of the resin and disturbing the arrangement of the molecular chains, thereby The strength of the in-mold label container 1 is improved without changing the overall thickness. Therefore, the in-mold label container 1 of the present embodiment can reduce the thickness of the container body 2 while maintaining a strength sufficient to withstand the use environment. Therefore, the amount of resin used for molding the in-mold label container 1 can be suppressed, and the product cost can be suppressed and the volume can be reduced at the time of disposal.

In addition, this embodiment can also be changed and embodied as follows.
In the present embodiment, eight vertical ribs 24 are provided, but the number of vertical ribs 24 is not limited to this, and may be provided in the range of 2-7, or nine or more. May be.

  In the present embodiment, the vertical rib 24a is provided on the inner peripheral surface side of the gap portion 20E of the side wall 20, and the vertical rib 24a is formed wider than the other vertical ribs 24. Is not limited to this. For example, the vertical rib 24a may be formed with the same width as the other vertical ribs 24, or may be provided regardless of the position of the gap 20E.

  In the present embodiment, an annular peripheral edge portion 11 that forms a bulging surface that gradually bulges downward from the side wall 20 side, and a spherical central portion 12 that bulges upward toward the center side. However, the shape of the bottom wall 10 is not limited to this. For example, the entire bottom wall 10 may be formed in a hemispherical shape bulging downward. When formed in this way, in addition to the effect (4), the fluidity of the resin on the bottom wall 10 is also enhanced during molding. Moreover, you may form at least one of the peripheral part 11 and the center part 12 in a horizontal surface shape.

  -In this embodiment, although the two annular ribs 15 were provided in the center part 12 of the bottom wall 10, the number of the annular ribs 15 is not restricted to this, One may be sufficient and three or more It may be. Further, the annular rib 15 may not be provided.

  -In this embodiment, although the specific numerical value was shown and demonstrated about the thickness of each site | part in the container main body 2, this numerical value is only one Embodiment of this invention, and it may change suitably. Needless to say.

  In the present embodiment, the gap S formed between the side edges of the label 3 is formed so as to extend in the vertical direction with respect to the side wall 20, but the gap S may be inclined obliquely. In this case, the extending direction of the gap 20E, which is the part where the gap S is located, and the extending direction of the vertical rib 24a are different, but the vertical rib 24a is provided so as to overlap with a corresponding portion of the gap 20E. If it is, the effect of said (2) can be acquired. Even when the gap 20E is inclined with respect to the strict vertical direction, the inclined gap 20E is within the scope in which the effect of the above (2) can be substantially obtained. It is understood that it is included in the gap extending in the longitudinal direction as defined in claim 2 of the present invention.

  In the present embodiment, one label 3 is attached to the outer peripheral surface of the side wall 20, but a plurality of labels 3 may be attached to the outer peripheral surface of the side wall 20. In this case, wide vertical ribs 24a are formed inside each gap 20E so as to correspond to each gap 20E where the gap S formed between adjacent labels 3 is located. Further, the label 3 does not have to be adhered or welded to the container body 2.

  In this embodiment, the label 3 has a lateral length smaller than the outer periphery of the side wall 20, and a vertical length covers a part of the flange 25 and covers most of the legs 21. However, the size of the label 3 is not limited to this. For example, the dimension may be set such that the gap S is not formed, or the width of the gap S is not constant and may be set to be different in the vertical direction.

Next, a technical idea that can be grasped from the above embodiment and another example will be described.
● An in-mold label container comprising a bottomed cylindrical container body which is formed of a synthetic resin and has a cylindrical side wall and a bottom wall and has an opening, and a label which is bonded or welded to the outer surface of the container body And the said bottom wall forms the bulging surface which the peripheral part bulges toward a downward direction, The in-mold label container characterized by the above-mentioned.

  An in-mold container formed of synthetic resin and having a cylindrical side wall and a bottom wall, and a plurality of vertical ribs projecting into the side wall and extending in the vertical direction on the inner peripheral surface of the side wall An in-mold container is provided.

The perspective view which shows the in-mold label container of this embodiment. XX sectional drawing in FIG. YY sectional drawing in FIG. The perspective view which shows the bottom wall periphery of the in-mold label container of this embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... In-mold label container, 2 ... Container main body, 3 ... Label, 10 ... Bottom wall, 11 ... Peripheral part, 12 ... Center part, 15 ... Annular rib, 20 ... Side wall, 20D ... Cover part, 20E ... Gap part, 24, 24a ... vertical ribs.

Claims (4)

An in-mold label container comprising a bottomed cylindrical container body formed of a synthetic resin and provided with a cylindrical side wall and a bottom wall and having an opening, and a label adhered or welded to the outer surface of the container body There,
The inner peripheral surface of the side wall is provided with a plurality of vertical ribs that protrude inward of the container body and extend in the vertical direction ,
The side wall includes a covering portion covered with a label, and a gap portion extending in a vertical direction formed between a side edge of the label and a side edge of the label, and one of the vertical ribs is An in-mold label container, which is provided inside the gap portion on the side wall . 2. The in-mold label container according to claim 1 , wherein the vertical rib provided inside the gap is formed wider than the other vertical ribs. The in-mold label container according to claim 1 or 2 , wherein the bottom wall is formed with a bulging surface whose peripheral edge bulges downward. The in-mold label container according to any one of claims 1 to 3 , wherein the bottom wall is provided with an annular rib projecting downward at a central portion thereof.

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