JPWO1997024212A1 - Manufacturing method of foamed resin container with label and manufacturing device - Google Patents

Abstract

(57) [Abstract] The present invention provides a method and apparatus for easily and continuously manufacturing labeled foamed resin containers by supplying a sheet on which a label shape is printed in a predetermined position, and then positioning and punching out the label shape. This method involves a series of steps from molding while defining this position to forming the container. It also provides a manufacturing method that allows for more accurate positioning of the label. Therefore, it is possible to use a thin sheet of resin or other material with low stiffness, without using a base material such as paper, and to integrate the punched label in the predetermined position on the foamed resin container without first forming it into a predetermined cylindrical shape.

Description

[Detailed Description of the Invention] Method and Apparatus for Manufacturing Labeled Foamed Resin Containers Technical Field The present invention relates to a method and apparatus for manufacturing labeled foamed resin containers used for instant ramen cups, beverage cups for juice, hot coffee, etc., frozen dessert containers, and other packaging containers.

BACKGROUND ART Foamed resin containers have traditionally been widely used for instant foods, juices, and other beverages. These containers are typically manufactured using a foam molding process, in which pre-expanded resin particles, typically polystyrene-based resin containing a volatile blowing agent such as butane, pentane, or chlorofluorocarbon, are filled into a mold cavity and heated with a heating medium such as steam to expand the resin.

Labeled foamed resin containers are manufactured with various labels that can be printed on the containers to display product names, manufacturer names, patterns, and other designs, or to impart excellent gas barrier properties to the foamed resin containers.

Known methods for applying such labeling to the surface of foam resin containers (foam bead cups) include printing the labeling content directly onto the surface of the foam resin container using a printer, adhering a label with the labeling content pre-printed on it to the foam resin container, and wrapping a heat-shrinkable film with the labeling content pre-printed on it around the foam resin container and then heat-shrinking it to attach it, a method known as the shrink label method.

However, methods that directly print on the surface of foamed resin containers make it difficult to achieve clear prints like gravure printing or multi-color overlay printing. Furthermore, methods that attach pre-printed labels to foamed resin containers require separate processes for molding the container, punching out the label, and attaching the label. This makes the label attachment process cumbersome, as it requires precise alignment and attachment. Furthermore, shrink label methods that use heat-shrinkable film simply adhere to the cup due to thermal shrinkage, making the film prone to detaching from the cup if the cup's outer surface is sloped.

To solve these problems, Japanese Patent Application Laid-Open No. 4-331132 discloses a method for decorating foam-molded containers. This involves forming a printed paper sheet into a predetermined cylindrical shape, with a heat-sealable layer on the inner surface of a core paper with a printed outer layer. This sheet is then placed in a mold cavity, and the cavity is evacuated through numerous vent holes in the female mold, fixing the printed sheet to the inner surface of the female mold cavity. The female and male molds are then mated, and expandable resin particles are filled between the printed paper sheet and the core of the male mold, followed by foam molding. The printed paper sheet is then fused to the foam-molded container by heating and expanding the foam-molded container.

However, this method requires punching a paper printing sheet into the desired shape and then forming it into a cylindrical shape, making the process complicated. Furthermore, the paper printing sheet used is composed of a printing layer on the outside of a core paper and a heat-seal layer on the inside. Paper printing sheets have poor moisture-proofing and gas-barrier properties. As a result, the paper absorbs moisture from the steam used in molding the foamed plastic container, which can cause the print to blur. Furthermore, because the outer printing layer of the paper printing sheet directly contacts the female mold, the printing ink is easily transferred to the female mold by heat. This transfer results in a faint print on the foamed plastic container, resulting in a printing defect. Furthermore, the ink transferred to the female mold is re-transferred to the surface of the next molded product, resulting in repeated printing defects.

Furthermore, this paper printing sheet needs to be formed into a cylindrical shape before molding, which complicates the process and increases costs.

The present invention overcomes these conventional problems by providing a novel method and apparatus for manufacturing labeled foam resin containers. This method uses a thin, weak synthetic resin sheet, rather than a paper substrate, on which a label is pre-printed with a clear design featuring fine text and smooth gradation. Furthermore, this weak label can be integrated into the foam resin container in the desired position without first forming it into a cylindrical shape prior to molding.

More specifically, the present invention provides a manufacturing method and manufacturing apparatus that can easily and continuously carry out a series of steps from the step of feeding labels in sheet form, on which printing has been performed in a predetermined position on the sheet, to the step of punching the labels, to the step of forming labeled foam resin containers.

<Disclosure of the Invention> To achieve the above-mentioned objectives, a preferred embodiment of the present invention includes: When integrally molding a labeled foam resin container with a label placed on the outer periphery of the container's side, positioning and feeding a continuous sheet with a printed label shape at a punching position of a label punching device; punching out the label shape and then fixing the label at the punching position on a label receiving table having a means for fixing the label; moving the label receiving table with the fixed label position and feeding the label to a predetermined position on a pseudo-male mold; wrapping the label around the pseudo-male mold by injecting pressurized gas and then suctioning air through an air hole provided in the pseudo-male mold to fix the label to the pseudo-male mold; This process involves the following steps: After the pseudo-male mold with the label attached is mated with the female foam molding mold, suction is applied through the air hole in the female foam molding mold, and the label is transferred to and tightly fixed in place on the inner surface of the female foam molding cavity by either stopping the suction on the pseudo-male mold or applying pressure through the air hole in the pseudo-male mold; With the label tightly fixed to the inner surface of the cavity, the pseudo-male mold and the female foam molding mold are opened; After clamping the male foam molding mold and the female foam molding mold, foam resin particles are filled in and heated to form a foam resin container, integrating the label and the container.

Furthermore, a preferred embodiment of the manufacturing apparatus of the present invention is an apparatus for automatically manufacturing labeled foam resin containers, from label punching to integral molding, with labels arranged on the outer periphery of the container's side surface. It includes: a sheet supply device equipped with a mechanism for positioning labels on a continuous sheet on which the label shape is printed; a label punching device equipped with a mechanism for punching labels of a predetermined shape from the supplied sheet, a label receiving table for fixing the punched label in place and movable to a predetermined position on the pseudo-male mold; and a device for winding up the sheet after the label has been punched out. Furthermore, the pseudo-male mold, which has an air hole for suction to fix the wrapped label after wrapping it around the pseudo-male mold using a pressurized gas injection mechanism, and a foam molding female mold are matably arranged. Furthermore, the foam molding male mold is provided with a suction hole for sucking and fixing the label after transferring it from the pseudo-male mold to the inner surface of the foam molding female mold, a supply hole for supplying expandable resin particles, and a heating means for foam molding, and the foam molding female mold is provided with a heating means for foam molding and is arranged so that the molds can be clamped.

In this invention, for continuous sheets with label shapes printed in predetermined positions, the label shapes are first positioned and fed, and then the labels are punched out. A label receiving table with a means for fixing the labels in place is used to move the labels to their predetermined positions on the pseudo-male mold. Therefore, only one positioning step is required before punching the labels; subsequent positioning is not required. Furthermore, since the synthetic resin labels wrapped around the pseudo-male mold are held in place by suction through an air hole, there is no need to pre-form the labels into a cylindrical shape.

This allows for easy and efficient production of foamed resin containers with labels integrated into the container's outer periphery at a predetermined location. Furthermore, the process of forming the label into a cylindrical shape is no longer necessary, eliminating the need for complex processes or special equipment, and further simplifying the equipment.

The manufacturing device also includes a label receiving table that punches labels from a sheet on which the label shape is printed, has a label-shaped hole in the punching plate that holds the label, and moves the label through the hole above the punching plate. The label receiving table may also be configured with an air hole for pressurizing and depressurizing.

In this device, the punched label held on the punching plate can be fed directly to the pseudo-male mold, so once the label position is determined, it will not be changed.

Furthermore, in another preferred embodiment of the present invention, a manufacturing method for integrally molding a labeled foam resin container with a synthetic resin label attached to the outer periphery of the container's side surface includes the following steps: Wrapping the label around a pseudo-male mold and suctioning the label through air holes in the pseudo-male mold to hold it in place; Cutting off the suction from the pseudo-male mold just before mating the pseudo-male mold with the label against the female foam molding mold, or correcting any misalignment of the label by mating the pseudo-male mold with the female foam molding mold; Applying pressure to the label through the air holes in the pseudo-male mold to transfer the label to the inner surface of the cavity of the female foam molding mold and secure it in place; Opening the pseudo-male mold and the female foam molding mold with the label in place and securely attached to the inner surface of the cavity. While maintaining the label in intimate contact with the inner surface of the cavity, the female mold for foam molding and the male mold for foam molding are clamped together, and then foamable resin particles are filled in and heated for foam molding, thereby forming a foam resin container and simultaneously integrating the container and the label.

In the above invention, suction from the pseudo-male mold is stopped just before the pseudo-male mold holding the label is mated with the female foam molding mold, and any misalignment of the label is corrected by mating the pseudo-male mold with the female foam molding mold. Therefore, even if the label is misaligned while wrapped around the pseudo-male mold, the label is temporarily set free for mating, correcting the misalignment. In the subsequent process, pressure is applied to the label through the air hole in the pseudo-male mold, and the label is transferred to the inner surface of the cavity of the female foam molding mold and tightly secured, setting it in the desired position.

Then, while maintaining the label in intimate contact with the inner surface of the cavity, the female and male foam molding dies are clamped together, and the foamable resin particles are filled in. Then, by heating and foam molding, the container and the label are integrated simultaneously with the molding of the foamed resin container. This effectively prevents label misalignment and integrates the two together as the foamed resin container is molded, eliminating the need to first form the label into a cylindrical shape before molding.

Therefore, by using a thin, weak synthetic resin sheet that does not use a paper or other substrate, and by using labels pre-printed with clear designs that display fine text and smoothly varying gradations, the label can be integrated into the foamed resin container in the designated position while effectively preventing misalignment, allowing for efficient production of labeled foamed resin containers with synthetic resin labels attached to the outer periphery of the container's side surface using a simplified process.

Furthermore, the resulting labeled foamed resin container has an attractive label that does not protrude from the surface and is also resistant to peeling. This makes it possible to easily produce foamed resin containers, such as containers with labels printed with fine text, clear text with smoothly varying gradations, and text printed using multicolor overlay printing.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 shows one embodiment of the present invention. It is a schematic diagram of an apparatus that feeds a sheet with a label shape printed in a predetermined position, punches it out, and moves the label.

FIG. 2 is a front view of a sheet on which label shapes are printed in predetermined positions.

FIG. 3 is a cross-sectional view of the punching device.

4(1) to 4(3) are explanatory diagrams of the process of wrapping the label around the pseudo-male mold.

FIG. 5 is a perspective view of a label winding device according to another embodiment.

FIG. 6 is an explanatory diagram showing the operation of the label winding device of FIG.

FIG. 7 is an explanatory diagram showing the positional relationship between the label winding device of FIG. 5 and the pseudo-male mold.

FIG. 8 is a cross-sectional view of the label wrapped around the pseudo-male mold.

FIG. 9 is a cross-sectional view of the pseudo-male mold and the foam molding female mold mated together.

FIG. 10 is a cross-sectional view of the label after it has been transferred to the female foam molding die.

FIG. 11 is a reference diagram showing a state in which a label wrapped around a pseudo-male mold is misaligned.

FIG. 12 is a cross-sectional view of a foam molding male mold and a female mold mated together.

FIG. 13 is a vertical cross-sectional view showing a foamed resin container with a label.

BEST MODE FOR CARRYING OUT THE INVENTION A preferred embodiment of the present invention is described below. In this invention, as shown in FIG. 1, label shapes 11 bearing text, patterns, designs, and other display content are punched out from a continuous sheet 1 onto which the label shapes 11 are printed and used as labels L. Reference numeral 11' denotes punch holes. As shown in FIG. 2, for example, fan-shaped label shapes 11 are printed on the sheet 1 at regular intervals. Furthermore, position detection marks 12 are printed between each pair of label shapes 11. These detection marks 12 are detected by a detection means 29, such as a photoelectric tube, which activates a sheet feed drive motor M1, which is connected to the detection means, thereby positioning the label shapes and feeding a fixed amount of the sheet 1.

Examples of materials for the sheet (film) on which the label shape 11 is printed include resin films made of thermoplastic resins such as polyethylene, polypropylene, high-density polyethylene, polyvinyl chloride, polyethylene terephthalate, polyamide, and polyvinylidene chloride, each containing 8 to 65% by weight of fine inorganic powder; films in which a latex containing an inorganic filler is coated on the surface of such resin films; and films in which aluminum is vapor-deposited on such resin films. Such substrate layers may be single layers or may have a laminated structure of two or more layers.

On the back side of the sheet (the side that contacts the foam resin container), an adhesive layer such as low-density polyethylene, vinyl acetate-ethylene copolymer, ethylene-(meth)acrylic acid copolymer, or metal salt of ethylene-(meth)acrylic acid copolymer can be used, if necessary. Among these, heat-sealable resins with a melting point of 85 to 135°C are preferred.

Furthermore, if the sheet on which the label shape 11 is printed and the resin constituting the foam resin container are made of the same resin or if a printing ink with excellent adhesive properties is used, it is possible to heat-seal the two during molding. However, if heat-sealing to the foam resin container is difficult, a heat-sealable adhesive layer may be provided on the back of the label L to ensure a more secure bond to the foam resin container. The adhesive layer may be the entire label L or a partial layer. The label L can be molded to a total thickness of 10 μm to 1 mm, with a thickness of 50 μm to 100 μm being more preferable.

After the label shape 11 is positioned in a predetermined position and the sheet 1 is fed, the fan-shaped label shape 11 is punched out. The punched label is shown with the symbol L. For punching, a punching device 2 such as that shown in Figures 1 and 3 is used.

Punching is performed by feeding the sheet 1 and then driving a punching drive unit 22 to punch a punching plate 20 having holes 21 corresponding to the label shape 11 to be punched. Furthermore, the punching plate 20 is provided with a label receiving base 23 having one or more air holes 24 for suction, for example, as a means for fixing the punched label L in place.

The punched label L is fixed to the label receiving base 23 at the punched position by suction through the air hole 24. After the label L has been punched out, the sheet 1 is wound up by the sheet winding device 3, which is operated by the sheet winding drive motor M2. It is preferable that the winding device 3 also operates in conjunction with the label shape detection means.

The label receiving table 23 is provided so as to be movable together with the punching plate 20 from the position of the label punching device 2 to the position where the label L is wrapped around the pseudo-male die 5.

Position detection means for determining the position of the label receiving table 23 are provided at the label punching position and the position where the label L is wrapped around the pseudo-male die 5 as needed.

As shown in Figure 4, the die-cutting plate 20 with the label L fixed thereto by suction is moved to a predetermined position, and the label receiving table 23 is moved upward to set the label L at a position where it will be wrapped around the pseudo-male mold 5. This position can be aligned with the pseudo-male mold 5 by any suitable detection means.

In the example shown in Figure 1, after cutting one label L, the label receiving table 23 and the punching plate 20 move one label L apart to prepare for the next cut. However, it is also possible to move only the push-cutting drive unit 22 by one label, or to provide a push-cutting drive unit 22 capable of punching two labels L at a time. It is also possible to simultaneously cut more than two labels L and prepare a corresponding number of pseudo-male molds 5 to perform multi-cavity molding of labeled foam resin containers. An example of a multi-cavity molding system with four labels is shown in the embodiment of Figure 5 below.

As shown in Figures 4(1)-(3), the cut label L is wrapped around the pseudo-male die 5 by spraying pressurized gas. The spraying of pressurized gas to wrap the label L around the pseudo-male die 5 is accomplished by placing the pseudo-male die 5 in contact with the approximate center of the label L as shown in Figure 4(1), closing the pressure reducing valve 25 connected to the air hole 24 on the label receiving base 23, and simultaneously opening the pressure increasing valve 26 to spray pressurized gas. This spraying of pressurized gas is accomplished by using pairs of pressure reducing valves 25 and pressure increasing valves 26 on the left and right sides, as shown in Figures 4(2) and (3). This allows for a time lag in the wrapping of the label L, resulting in smooth overlapping of the edges and reducing the likelihood of wrinkles or creases, making this the most preferred method.

In this way, once the label L is positioned to the fixed position where it will be wrapped around the pseudo-male die 5 before the label shape 11 is punched out, the label receiving base 23 can be moved to the fixed position, so there is no need to perform any further steps. Furthermore, there is no need to form the label into a cylindrical shape.

The pressurized gas jet may be provided on the label receiving table 23 as described above. Alternatively, a separate label winding table equipped with a pressurized gas jet mechanism for winding the label L around the pseudo-male mold 5 may be provided, and a process of transferring the label from the label receiving table 23 to the label winding table via a transfer means such as suction may be included. This label winding table is particularly suitable for simultaneously producing a large number of labeled foam resin containers. For example, this may involve multiple rows of label shapes 11 printed on a film, or multiple rows of film with label shapes 11.

Figures 5-7 show another embodiment of an apparatus capable of forming four labels L simultaneously, which includes a label winding table equipped with a pressurized gas injection mechanism.

This device is equipped with a punching plate 31 having a label-shaped recess, and a label winding table 32 for picking up the punched label L on the punching plate 31 by suction and winding it around the pseudo-male mold 5.

The punch plate 31 holds the labels punched out by the drive of the push-cutting drive unit 22. In this example, a sheet of parallel labels is supplied, and the punch plate 31 holds two cut labels and moves them along one row, then holds the next two cut labels, moving a total of four labels L below the label winding table 32 at one time.

The label winding table 32 has two rows of support rods 33, which also serve as conduits for pressure reduction and pressure increase. Four suction units 34, each with two air pipes, are attached to the support rods 33. The suction units 34 are connected to pressure reduction and pressure increase valves, as in the previous embodiment.

The two support rods 33 are horizontal when the label L is being transported and attracted, but when the label is being fed to the pseudo-male mold 5, the support portion 35 can be rotated 90 degrees so that the two support rods 33 are aligned vertically, as shown in Figures 6 and 7.

To wrap the labels around the pseudo-male molds 5, the pseudo-male molds 5 are moved above the respective label winding tables 32 holding the labels L. The wrapping of the labels L by pressurized gas injection is performed in the same manner as in the above-described embodiment.

As an alternative configuration for wrapping the label around the pseudo-male mold 5, the support portion 35 can be moved along with the suction portion 34, which still holds the label, without moving the pseudo-male mold 5.

The label L held by the label receiving table 23 or label winding table 32 is wound around the pseudo-male mold 5 by spraying pressurized gas onto the label L, as described above. However, the pseudo-male mold 5 also has multiple air holes 52 on its side, which apply vacuum to the wrapped label L for tight adhesion. The air holes 52 may be, for example, elongated grooves or circular recesses. The pseudo-male mold 5 is made larger than the foam molding male mold 7 (described below) so that it can be closely fitted with the female molding mold 6 with the label L secured in place. As shown in Figures 8 and 9, an air chamber 53 is provided inside the pseudo-male mold 5, and a passage 51 is provided at the bottom of the pseudo-male mold 5 for depressurizing (vacuuming) or pressurizing the air chamber 53. The passage 51 is equipped with a pressure reducing valve 54 or a pressure increasing valve 55 (see Figure 11) and is connected to a pressure device (not shown). As a result, when the pressure reducing valve 54 of the pseudo-male mold 5 is opened, the pressure in the air chamber 53 of the pseudo-male mold 5 can be reduced through the passage 51, allowing the label L to be sucked in through the passage 51. When the pressure increasing valve 55 is opened, the pressure in the air chamber 53 of the pseudo-male mold 5 can be increased through the passage 51.

The air hole 52 is connected to an air chamber 53, and an air release valve 56 is provided to instantly return the depressurized or pressurized air chamber 53 to atmospheric pressure.

By wrapping the label L around the side of the pseudo-male mold 5 in this manner and reducing the pressure in the air chamber 53 to, for example, 200 to 740 mmHg, the label L can be fixed to the side of the pseudo-male mold 5. The pressure in the air chamber 53 can be set appropriately depending on the thickness (weight) of the label L.

After the label L is suction-fixed, the pseudo-male mold 5 may be inverted so that the portion containing the pseudo-male mold 5 approaches the female foam molding mold 6 (hereinafter referred to as the female mold), or the entire portion containing the pseudo-male mold 5 may be moved. Alternatively, the female foam molding mold 6 and the pseudo-male mold 5 may be mated by bringing the female foam molding mold 6 closer to the pseudo-male mold 5. In the next step, as shown in FIG. 9, the pseudo-male mold 5 is inserted into the female mold 6 and mated. Then, vacuum suction (reduced pressure suction) is initiated through the air hole 65 of the female mold 6, and simultaneously pressure is applied through the passage 51 of the pseudo-male mold 5, or suction through the passage 51 of the pseudo-male mold 5 is stopped. This causes the label L to separate from the pseudo-male mold 5 and move to the inner surface of the cavity of the female mold 6, where it is tightly fixed.

As shown in FIG. 10 , the female mold 6 has an annular groove 66 formed on the inner surface of the cavity along the upper and lower edges of the label L that has been transferred to and abutted against the inner surface of the cavity, vertical grooves (not shown) formed on the inner surface of the cavity along the left and right edges of the label L, and air holes 65 for reducing the pressure in the space between the label L abutting against the inner surface of the cavity and the annular groove 66, as well as in the space between the label L and the vertical grooves.

The female mold 6 also has an internal steam chamber 62, which allows for indirect heating of the female mold 6 by introducing steam into the steam chamber 62. Furthermore, the female mold 6 is equipped with a filling device (not shown) for filling the cavity 8 (described below) with raw material through a raw material supply hole 61, a steam and cooling water supply port 63, a drain outlet 64, and an air supply port (not shown) for transferring the molded product to the foam molding male mold 7.

The annular groove 66 is formed at a position corresponding to 0.1 to 2 mm, more preferably 0.2 to 0.5 mm, from the upper (lower) end of the label L, and has a width and depth of 0.1 to 1 mm. The vertical grooves are formed at positions corresponding to 0 to 3 mm from the left and right ends of the label L, and have a width and depth of 0.1 to 1 mm.

When applying label L to the entire side, it is preferable to overlap the left and right edges of label L to some extent while it is tightly secured to the inner surface of the cavity. However, if the overlap is too large, much of the label L will be wasted, which is uneconomical. For these reasons, it is desirable to set the overlap between 0 and 10 mm.

Furthermore, to more accurately position the label L without misalignment, the following method can be adopted. The label L wrapped around the pseudo-male mold 5 may sometimes become misaligned as shown in Figure 11, and this method effectively prevents such misalignment.

Immediately before mating the pseudo-male mold 5 with the label L fixed thereto with the female foam molding mold 6, the suction of the pseudo-male mold 6 is stopped, and more preferably, the depressurized air chamber 53 is instantly returned to atmospheric pressure via the atmospheric release valve 56. By mating the pseudo-male mold 5 with the female foam molding mold 6 in this state, the suction of the label L by the pseudo-male mold 5 is stopped, and the misalignment of the label L described above can be corrected to the specified position.

That is, when the pseudo-male mold 5 and the foam molding female mold 6 are arranged one above the other and the lower pseudo-male mold 5 is moved upward, suction from the pseudo-male mold 5 is stopped immediately before the molds are mated. More preferably, the depressurized air chamber 53 is instantly returned to atmospheric pressure via the atmospheric release valve 56, freeing the label L. The label L then moves downward naturally under its own weight, and is positioned by being supported by the lug 59 at the lower end of the pseudo-male mold 5. Furthermore, since the upper end of the label L abuts against the upper inner surface of the foam molding female mold 6, the position of the label L can be corrected.

Even in the case of a mold in which the pseudo-male mold 5 is positioned above the female foam molding mold 6 and inserted by moving downward, the suction of the pseudo-male mold 5 can be stopped just before the two molds are mated, allowing the inner surface of the cavity of the female mold 6 to be used to correct any misalignment of the label L.

With the misalignment of the label L thus corrected, the pseudo-male mold 5 is inserted into the female foam molding mold 6, and then the air chamber 53 is pressurized. As a result, air is injected from the air hole 52 and pressurizes the label L against the inner surface of the female foam molding mold 6, causing the label L to separate from the pseudo-male mold 5 and transfer to the inner surface of the cavity of the female foam molding mold 6, where it is tightly fixed.

Molding of a labeled foamed resin container using this method can be performed in the same manner as in the above embodiment. In this embodiment, the label L can be positioned more accurately.

Furthermore, while maintaining the label L in close contact with the inner surface of the cavity, the pseudo-male mold 5 is removed from the female mold 6, and the foam molding male mold 7 is clamped against the female mold 6. For example, a press machine for bead foam molding is used for this purpose. As shown in FIG. 12, the press machine consists of an upper fixed platen 60 and a lower movable platen 70 that moves up and down by a ram 75. The female mold 6 is fixed to the fixed platen 60, and the foam molding male mold 7 is fixed to the movable platen 70. When the female mold 6 and the foam molding male mold 7 are clamped together, a container-shaped cavity portion 8 is formed between them.

The foam molding male mold 7 has an internal steam chamber 71 and is equipped with a steam and cooling water supply port 72, a drain outlet 73, and an exhaust air port (not shown). Furthermore, although not shown, it is equipped with various pressure reducing valves (regulators) and solenoid valves, such as a fill air valve, a steam valve, a direct heating valve for the cavity portion 8, a drain valve, a cooling water valve, and an exhaust air valve, as well as a control panel for controlling these valves.

As shown in Figure 13, for example, a foamed resin container is manufactured by in-mold bead expansion molding using polystyrene resin beads containing a blowing agent, 0.25 mm in diameter, which are pre-expanded to a bulk ratio of 12 (0.57 mm in diameter). The pre-expanded beads are then expanded to a bulk ratio of 12 (0.57 mm in diameter). The container has a top diameter of 96 mm, a bottom diameter of 68 mm, a height of 107 mm, and a body thickness of 2 mm.

The resins that make up the expandable thermoplastic resin used as the raw material for foamed resin containers are not particularly limited as long as they can contain a blowing agent and be capable of in-mold bead foam molding, such as polystyrene-based resins such as polystyrene, high-impact styrene, styrene-maleic anhydride copolymer, and styrene-acrylonitrile copolymer, polyolefin-based resins such as polyethylene, polypropylene, and ethylene-vinyl acetate copolymer, and mixtures of these resins.

Specifically, the molding of labeled foam resin containers is carried out as follows: The vacuum valve of the female mold 6 is opened, and the pressure in the space between the label L and the suction groove 66 is reduced through the air hole 65. This allows the label L to be tightly fixed to the inner surface of the cavity of the female mold 6, and the pseudo-male mold 5 is then removed.

The female mold 6 and the foam molding male mold 7 are closed and clamped, the fill air valve is opened, and the pre-expanded particles are filled into the cavity 8. Steam is then introduced into the steam chamber 62 of the female mold 6 and the steam chamber 71 of the foam molding male mold 7 to heat them. At this time, the drain valve is opened to drain condensed water.

Next, the direct heating valve is opened to directly heat the cavity portion 8. Once the foam particles are fused together, the cooling water valve is opened to cool the entire system. After cooling, the exhaust air valve is opened, and the labeled foam resin container C is transferred to the foam molding male mold 7 and ejected. The movable platen 70 is then lowered by the ram 75, the mold is opened, and the labeled foam resin container C is removed.

In this example, the label L was made of a 30 μm thick polypropylene film with a reverse printing and a 30 μm thick vinyl acetate-ethylene copolymer adhesive layer formed on the reverse printing of the polypropylene, for a total thickness of 60 μm.

Furthermore, according to this embodiment, labeled foam resin containers can be molded efficiently and in a single unit with fewer steps. Furthermore, the position of the label L on the container does not shift, and the label L does not easily peel off. Furthermore, containers can be easily manufactured with labels L printed on their surfaces, including fine text, clear text with smoothly varying gradations, and text printed using multicolor overlay printing. Furthermore, there are no air bubbles between the label L and the foam resin container, and the label L does not wrinkle, resulting in an aesthetically pleasing appearance. Furthermore, labeled foam resin containers are not limited to those shown in the drawings, and can be manufactured for containers of various different shapes.

When a label L is used in which printing is applied to the adhesive surface between the foam resin container and the label L, the ink in the printed layer does not transfer to the female mold 6 due to heat, preventing printing defects caused by transfer. Examples of such labels L include those composed of a transparent resin sheet, a printed layer, and, if necessary, an adhesive layer. Furthermore, using resin instead of paper for the label L makes it less susceptible to moisture absorption, even when steam heating is used during molding of the foam resin container.

Labels L are made of a material with excellent gas barrier properties, and the labels L are integrally molded onto the entire side of the product. These products are particularly moisture-proof and gas-blocking, making them ideal for use as food containers that can be stored for long periods of time.

Label L may be applied to only a portion of the side surface rather than the entire surface. For example, label L may be shorter than the height of the body of the molded product. Applying label L only to the center of the body of the molded product in this way can prevent the body of the molded product from swelling due to moisture absorption from the contents of ramen noodles, etc. Applying label L only to the upper part of the body of the molded product reinforces the strength of the opening, resulting in a more affordable molded product.

As described above, the present invention provides a method and manufacturing apparatus for manufacturing labeled foam resin containers using a thin sheet of resin or other material with low stiffness, without using a base material such as paper, and by punching out a label shape printed on the sheet without first forming it into a predetermined cylindrical shape, and then integrating this as a label into a foam resin container at a predetermined position. Therefore, labeled foam resin containers can be easily and continuously manufactured through a series of processes, from supplying a sheet with a printed label shape in a predetermined position, positioning and punching the label shape, and molding the container while maintaining this position.

The present invention provides a continuous sheet with a label shape printed in a predetermined position, positions the label before punching it, punches it out, fixes the label in place on the label holder, and then moves the label holder and pseudo-male mold into position. This eliminates the need for subsequent positioning. This allows for easy and efficient production of foamed resin containers with labels integrated into the container's outer periphery in a predetermined position. Furthermore, this eliminates the need for a process to first form the integrated label into a cylindrical shape, eliminating the need for complex processes and special equipment, further simplifying the manufacturing process.

In this method, suction from the pseudo-male mold is stopped just before the pseudo-male mold holding the label is mated with the female foam molding mold, and any misalignment of the label is corrected by mating the pseudo-male mold with the female foam molding mold. Even if the label is misaligned when wrapped around the pseudo-male mold, the label can be temporarily set free during mating, allowing the mating action to correct the misalignment. In the subsequent process, pressure is applied to the label through the air hole in the pseudo-male mold, and the label is transferred to the inner surface of the cavity of the female foam molding mold, where it is tightly secured, allowing it to be accurately set in the desired position in the female mold.

The resulting labeled foam resin container has no air bubbles between the label and the foam resin container, and the label is wrinkle-free. Furthermore, the label does not protrude from the surface of the foam resin container, is aesthetically pleasing, and is resistant to peeling. This allows for the easy production of containers with labels printed with fine text, clear text with smoothly varying gradations, and multicolor overlay printing.

───────────────────────────────────────────────────── Continued from the front page (72) Inventor: Akio Tsujita 2-9-30 Kamishinden, Toyonaka City, Osaka Prefecture 501 Rose Villa, Senri Chuo (72) Inventor: Hirotomo Iwasaki 6-10-27 Nomura, Kusatsu City, Shiga Prefecture 401 Excel Court (72) Inventor: Masaru Chiba 1-1-57-601 Onohama, Otsu City, Shiga Prefecture (Note) This publication is based on the publication published internationally by the International Bureau of Patents (WIPO). The effect of the international publication of the Japanese patent application (Japanese utility model registration application) related to this publication arises pursuant to Article 184-10, Paragraph 1 of the Patent Act (Article 48-13, Paragraph 2 of the Utility Model Act) and is unrelated to this publication.

Claims (4)

[Claims] 1. In the process of integrally molding labeled foam resin containers with labels positioned around the outer periphery of the container's side, the process involves: positioning and feeding a continuous sheet with a printed label shape to a punching position in a label punching device; punching out the label shape and then fixing the label on a label receiving table having a means for fixing the label at the punching position; moving the label receiving table with the fixed label position and feeding the label to a predetermined position on a pseudo-male mold; wrapping the label around the pseudo-male mold by injecting pressurized gas and suctioning air through an air hole provided in the pseudo-male mold to fix the label to the pseudo-male mold; mating the pseudo-male mold with the fixed label with a female foam molding mold, and then suctioning air through an air hole provided in the female foam molding mold, and then transferring the label to the inner surface of the female foam molding mold cavity and fixing it in place by either stopping the suction on the pseudo-male mold or applying pressure through the air hole in the pseudo-male mold; This method for manufacturing a labeled foam resin container includes the following steps: Opening the pseudo-male mold and the female foam molding mold while the label is tightly secured to the inner surface of the cavity; Clamping the male foam molding mold and the female foam molding mold together, filling them with expandable resin particles, and then performing heat foam molding to form the foam resin container and simultaneously integrate the label and the container. 2. An apparatus for automatically manufacturing labeled foam resin containers, from label punching to integral molding, with labels positioned on the outer periphery of the container's side surface. The apparatus includes: a sheet feeder equipped with a mechanism for positioning labels printed on a continuous sheet; a label punching device equipped with a mechanism for punching labels of a predetermined shape from the supplied sheet, a label punching device equipped with a label receiving table that fixes the punched label in place and is movable to a predetermined position on the pseudo-male mold; and a device for winding up the sheet after the label has been punched out. Furthermore, the pseudo-male mold, equipped with an air hole for suction to fix the wrapped label after the label is wrapped around the pseudo-male mold using a pressurized gas injection mechanism, and a foam molding female mold that can be mated. The apparatus for manufacturing labeled foamed resin containers further comprises a male foam molding mold equipped with a suction hole for sucking and fixing the label after transferring the label from the pseudo-male mold to the inner surface of the female foam molding mold, a supply hole for supplying expandable resin particles, and a heating means for foam molding, and the female foam molding mold equipped with a heating means for foam molding is arranged so that the molds can be clamped. 3. The manufacturing apparatus for labeled foam resin containers according to claim 2 includes a label receiving table that punches labels from a sheet on which the label shape is printed, has a label-shaped hole in the punching plate that holds the label, punches the label through the hole, and moves the label above the plate, and the label receiving table is provided with an air hole for pressurizing and depressurizing. 4. In the integral production of labeled foam resin containers with a synthetic resin label attached to the outer periphery of the container's side, the steps include: Wrapping the label around a pseudo-male mold and holding the label in place by suction through the air holes in the pseudo-male mold; Cutting off the suction from the pseudo-male mold just before mating the pseudo-male mold with the label against the female foam molding mold, or correcting any misalignment of the label by mating the pseudo-male mold with the female foam molding mold; Applying pressure to the label through the air holes in the pseudo-male mold, transferring the label to the inner surface of the cavity of the female foam molding mold and securing it in place; Opening the pseudo-male mold and the female foam molding mold with the label secured in place against the inner surface of the cavity. A method for manufacturing a labeled foamed resin container, comprising: clamping a female foam molding mold and a male foam molding mold together while maintaining the label in intimate contact with the inner surface of the cavity; filling the mold with expandable resin particles; and then heating and foaming the molded container to integrate the container and the label at the same time.