MX2013003745A - Method and apparatus for producing labeled, plastic foam containers and product of same. - Google Patents

Abstract

A method and apparatus for producing labeled, plastic foam containers, such as a labeled EPS cup uses a heated pocket to thermally bond a label to a freshly-made plastic cup such that a finished cup with a label can be made in considerably less time than the three or four weeks for conventional methods. The heating of the pocket is carried out using heated oil being supplied to an interior of cavity from which the heated pocket is formed. Also described is a labeled plastic foam container, such as a labeled EPS cup, having high quality printing capabilities, sufficient stiffness, acceptable insulation and barrier properties and reduced production cost and time.

Description

METHOD AND APPARATUS FOR PRODUCING FOAM CONTAINERS PLASTIC, LABELS AND YOUR PRODUCT Field of the Invention This invention relates to a method and apparatus for producing labeled plastic foam containers, such as, for example, a labeled expanded polystyrene cup. It also refers to the labeled plastic foam container, such as a labeled expanded polystyrene cup.

Background of the Invention Plastic foam containers, such as cups and other receptacles, are widely used. Said containers can be made of different materials, including expanded polystyrene (EPS). Plastic foam containers, such as those made of EPS, are relatively inexpensive and have excellent insulating properties to contain both hot and cold fluids. However, plastic foam containers typically have low printing capabilities. That is, it is difficult to apply printed or graphic designs directly to the surface of plastic foam containers, such as EPS containers.

In order to improve aesthetics and other properties, it is convenient to apply a label to a plastic foam container. Traditional labeling devices have certain limitations. For example, it is often difficult to apply labels to foam containers having conical surfaces, such as glasses. Is particularly difficult to cover substantially all the outer surface of said container, such as the entire outer wall of a vessel. It is also difficult to obtain an appropriate and consistent union between the label and the glass.

Additionally, there are drawbacks since 'freshly made vessels are subject to shrinkage after they are formed. As a result, there is a waiting time between the formation of the cups and the time when the labels can be applied, so that the shrinkage of the cup is taken into account.

Accordingly, it is convenient to provide a process for forming a labeled plastic foam container, in which: (1) the labels are applied at a sufficiently high speed; (2) a good union between the container and the label is obtained; and (3) the waiting time between the formation of the container and the addition of the label is reduced. Improving the bond between the foam container and the label includes avoiding a poor bond, for example, due to the formation of air bubbles or loose edges; and avoid loose labels wrapped in the labeled foam container.

Summary of the Invention According to one aspect of the invention, a plastic foam container labeled by the following steps can be manufactured: apply an outer sleeve to the exterior surface of a portion of unlabeled plastic foam, which is capable of substantially shrinking if it is left unheated; heating a work piece using a hot oil that is supplied inside the Workpiece; the workpiece defining a cavity having a bottom wall and a side wall, so as to correspond in shape with the outer surface of the plastic foam portion; placing the work piece so that the cavity surrounds the outer surface of the portion of plastic foam to which the outer sleeve is applied; heating the outer surface of the portion of plastic foam to which the outer sleeve is applied, with the cavity, by transferring heat by conduction from the workpiece to the outer surface of the plastic foam portion, when the portion of plastic foam is disposed within the cavity, at a temperature and for a time sufficient to attach the label to the outer surface of the plastic foam portion, and sufficient to prevent shrinkage of the plastic foam portion; the transfer of heat by conduction is caused by the heated oil that is inside the work piece; and remove the outer sleeve and the plastic foam portion. In a preferred embodiment, the plastic foam container is a plastic foam cup.

According to another aspect of the invention, a method for labeling a plastic foam container may comprise: heating a work piece using a hot oil, which is supplied to the inside of the work piece; the workpiece defining a cavity; surrounding an outer surface of the plastic foam container on which a label rests, with the cavity; where the cavity is formed with a side wall and a bottom wall, so as to correspond in shape with the outer surface of the plastic foam container; the plastic foam container being capable of shrinkage if left unheated when the plastic foam container is surrounded by the cavity; heating the outer surface of the plastic foam container in which the label is seated with the cavity, by transferring heat by conduction from the workpiece to the outer surface of the plastic foam container, when the plastic foam container is arranged within the cavity, at a temperature and for a time sufficient to attach the label to the outer surface of the container, and sufficient to prevent shrinkage by the plastic foam container, to provide a labeled plastic foam container, resulting; the transfer of heat by conduction is caused by the hot oil that is inside the work piece; and removing the labeled, resulting plastic foam container.

Preferably the cavity is heated to a temperature in the range of about 80 ° F (27 ° C) to about 120 ° F (49 ° C).

According to another aspect of the invention, the cavity is used to apply pressure to the outer surface to which the label is applied.

According to yet another aspect of the invention, the cavity is formed within a metal cylinder (or a female mold member) which is located such that a male mold member, on which the plastic foam container is placed, is positioned. , can move in relation to the metal cylinder.

According to a further aspect of the invention, the label is placed on a damping attachment; then the container is placed inside the label that is in the cushioning attachment; the label and the container are then placed on a male portion of the cavity, and then the male portion of the cavity is placed under a female portion of the cavity, so that the cavity is placed surrounding the outer surface of the container of the cavity. plastic foam to which the label is applied.

According to another aspect of the invention, the method and apparatus according to the invention are used to manufacture labeled plastic foam containers; where the label has good printing characteristics. Preferably, the label is formed from at least one of the following: paper, aluminum or plastic film, and mixtures thereof. The person having ordinary skill in the art will understand the types of materials suitable for use on the label for the marked foam containers according to the present invention.

According to another aspect of the invention, the final labeled plastic foam container has an inner portion of plastic foam having a density of less than 0.8 g / cm 3 and an outer sleeve which adheres to an outer surface of said portion of internal plastic foam. The outer sleeve has an outward facing surface, to which the printing or graphic designs are applied, the outer sleeve providing stiffness to the inner portion. The label can be applied according to a method or a machine of the invention. Before labeling, the foam container may have a relatively low density and stiffness; but after the application of the label, it has a general stiffness and density that are comparable with those of conventional foam containers of similar size.

According to one aspect of the invention, the inner plastic foam portion defines a cup shape with a lip portion, a bottom portion and a side wall. Preferably, the inner portion of plastic foam comprises EPS.

The stiffness obtained by the combination of the plastic foam and the label materials allows the use of substantially less EPS resin compared to a common plastic foam container with comparable (or even smaller) volumetric capacity. The particular combination of a lower resin content, such as EPS resin, combined with an outer sleeve that provides improved stiffness, results in a container having a significantly lower cost than those. previous containers, made of paper and / or plastic. The outer sleeve dramatically improves the printing capacity compared to ordinary and ordinary foam containers. This can be obtained, in particular, by using a previously printed label. Additionally, the container according to the invention provides comparable or improved rigidity, comparable or improved barrier and insulation properties, compared to containers of comparable size.

Other aspects and other advantages of the invention will be apparent from the following detailed description. * Description of the Drawings of the Invention These aspects, features and advantages of the present invention, and others, will be apparent from the following description, from the appended claims and from the accompanying example embodiments, shown in the drawings, which are briefly described below.

Figure 1 is a schematic view of a machine for labeling a plastic foam container, according to a first embodiment of the invention.

Figure 2 is a top view of the labeling machine according to the first embodiment of the present invention, showing the location of the mandrels in the turret.

Figure 3 is a sectional view of a labeling machine according to the first embodiment, illustrating a device having a heated cavity located on top of a mandrel.

Figure 4 is a side perspective view of a labeling machine according to the first embodiment of the present invention.

Figure 5 is a side perspective view of a labeling machine according to the first embodiment of the present invention.

Figure 6 is a top perspective view of an outer sleeve transfer device, according to the first embodiment of the present invention.

Figure 7 is a perspective view of a labeled plastic foam container, made in accordance with one embodiment of the invention.

Figure 8 is a sectional view of a labeled plastic foam container, in which the foam wall of the container has a reduced wall thickness.

Figure 9 is a sectional view of a labeled plastic foam container, in which the foam wall of the container has a reduced density.

Figure 10 is an illustrative sectional view of a common and ordinary foam container, with optional label.

Figure 11 is a schematic view of a machine for labeling a plastic foam container, according to a second embodiment of the invention.

Figures 12A to 12N are schematic views of the machine for labeling a plastic foam container, according to the second embodiment of the present invention, in the process of applying the label to the plastic foam container.

Detailed Description of the Representative Modalities of the Invention The following describes machines for labeling plastic foam containers, and a process for using said machines, according to various embodiments of the present invention. However, it should be appreciated that the following description is intended to be merely exemplary of the various aspects of the invention, and should not limit the appropriate scope of the claims that come at the end.

Figure 1 is a schematic view of a machine 10 for forming a plastic foam container 15 labeling, according to a first embodiment of the invention. As illustrated, the machine 10 includes a turret 12 having a plurality of mandrels 14 attached thereto. Each mandrel 14 has a tapered shape and is configured to receive a plastic foam container 17.

The plastic foam container can be an EPS glass that is freshly made. By recent fact it is meant that the vessel has been made recently, to the extent that it is still subject to shrinkage if it is left unheated (i.e., left at room temperature), as a result of the process in which it was formed . For example, vessels that are less than 21 days old are still susceptible to shrinkage, since the vessels are cooled from their formation process. Freshly made containers subject to labeling can have less than 21 days of facts, preferably less than 10 days of facts and, more preferable, less than 5 days of facts. Of course, freshly made glasses can be used, such as glasses that have less than 1 day, 2 days, 5 days, 21 days, or any whole between them.

The use of freshly made glasses can provide several advantages. For example, the use of freshly made glasses is more efficient than conventional processes (which do not use freshly made glasses), since there may be less processing time. For example, a finished glass with a label can be made in less than 1 or 2 or 5 days, instead of the conventional three or four weeks. In addition, the use of freshly made glasses allows less storage space is needed, since it reduces the amount of time required for each vessel to "settle" until the shrinkage stops, which is in marked contrast to conventional processes that tend to use vessels that have been stored until their shrinkage has stopped.

The turret 12 of this example is driven by an arrow 16, which is operatively connected to a stepped feed transmission 18, of a type conventionally known in the art. The stepped feed transmission 18 rotates the turret 12 90 degrees, so that the mandrels 14 are accurately aligned in each of the stations 20, 22, 24, 26, as illustrated in Figure 2, which illustrates a top view of the labeling machine according to the first embodiment of the present invention, showing the location of the mandrels 14 in the turret 12. Although four stations are shown, it will be appreciated that any number of stations in the machine can be provided. 10 As illustrated in Figure 1, in a first station 20 the unlabeled plastic foam containers 17 are placed, on the mandrels 14, from the vessel dispensing apparatus 19, by means of an actuator 28. The vessel dispensing apparatus it may include a rotating turret that automatically loads the unlabeled plastic foam containers 17 into the mandrels 14. In a second station 22 the label 13 is applied to the plastic foam container 17, as discussed in more detail below. In a third station 24 the label 13 is attached to the container 17 of plastic foam to form the labeled plastic foam container 15. The labeled plastic foam container 15 is removed of the mandrel 14 in a fourth station 26.

Reference is now made to Figure 3. In a third station 24 a workpiece 30 is provided, formed as a metallic cylinder. The workpiece 30 is attached to a vertical arrow 31, which is pneumatically driven, in accordance with art-known techniques, for raising and lowering, as illustrated in Figures 1 and 3. In accordance with one aspect of the invention , the workpiece 30 has a cavity or receptacle 32 formed therein. The cavity can have a side wall and a bottom wall. In this embodiment, the open end of the cavity is oriented downward towards the turret 12.

The cavity or receptacle 32 has a tapered shape, configured to conform to the external dimensions of the plastic foam container disposed on a mandrel 14. The cavity or receptacle 32 is configured to accommodate the shape of the mandrels 14. As illustrated in FIGS. Figures 1 and 3, a pneumatic piston vertically drives the cavity (up and down, in this view) towards an opposite mandrel 14, disposed below the cavity 32.

According to one aspect of the invention, the cylindrical workpiece 30, including the cavity 32, is heated so that it can be used to attach a label to a plastic foam container disposed on a mandrel 14. In In this example, the work piece 30 is connected to an oil inlet line 34. The oil is fed through the oil inlet line 34, into the interior 36 of the piece 30 in a cylindrical shape, by means of which the inner surface 35 of the side wall of the cavity 32 can be rapidly heated. The application of Oil can be controlled automatically, for example, with a valve operated by a controller (not shown).

The transfer by conduction of the heat that results in the heating of the work piece 30 is caused by the heated oil introduced into the cavity, so as to be inside the interior of the work piece. The use of oil is attributed to the convenience of using a fluid that can provide a uniformly distributed temperature or a uniform temperature throughout the fluid. A more compressible fluid provides greater temperature variation; while a less compressible fluid provides less variation in temperature. Additionally, the use of oil not only provides more uniform heating, but also provides a higher heating temperature in less time, compared to steam. Additionally, the use of oil does not require much machinery, as in the case of steam. A suitable heating oil can be, for example, Seriola 2997 (which has the following properties: specific density at 15 °, 0.965, viscosity at 40 ° C, 220 cSt, viscosity at 100 ° C, 5.16 cSt, viscosity index, 80, pour point, -33 ° C, flash point, 300 ° C, total acid number, 0.03 mg KOH / g, and copper corrosion, 1A). Other heating oils can also be used. For example, a heating oil having the following properties can be used: Density at 15 ° C 829 kg / m3 Viscosity at 40 ° C 30.4 mm2 / s Viscosity at 100 ° C 5.91 mm2 / s viscosity index 135 Flash point 234 ° C Pour point -54 ° C Total acid number 0.03 mg KOH / g.

Optionally, the work piece 30 can be configured to be pushed upwards to apply pressure to a plastic foam container 17 and the label 13 disposed on the mandrel 14. Pressure can be applied mechanically or by air pressure. It can be found that the pressure application promotes a faster and more homogeneous bond between the label 13 and the foam container 17. Additionally, it has been found that heat transfer is improved to attach the containers to the labels 13, using pressure of air or mechanical pressure inside the receptacle.

The application of pressure in the mold also provides additional benefits. In a more conventional system a pressure sensitive adhesive is applied to the label, and then the label is wrapped on the container. The ends of the label overlap each other and these overlapping ends protrude from the container, which results in a less smooth surface of the container. In contrast, according to one embodiment of the present invention, the label is overlapped in a minor amount and placed on the container as an outer sleeve. During compression of the outer sleeve on the container, not only is the label attached to the container, but it is further pressed into the surface of the container. The result is a smoother surface, which is indicative of an injection molded process in which the label is placed in the mold and the container is formed around it. In other words, it is closer to the Seamless appearance of the label around the container.

The parameters of attachment of the label to the container can include the duration of the temperature, the temperature of the fluid and the pressure applied to the label and to the container. The duration of the application of pressure and temperature may be within the range of about 1 second to about 10 seconds, preferably from about 2 seconds to about 5 seconds; very preferable, about 3 seconds. The temperature of the fluid can vary from about 100 ° C to about 140 ° C, preferably from about 115 ° C to about 135 ° C; very preferable, around 128 ° C. The applied pressure can vary from about 20 psi (0.137 MPa) to about 100 psi (0.689 MPa), preferably from about 40 psi (0.275 MPa) to about 80 psi (0.551 MPa); very preferable, around 60 psi (0.413 MPa).

The parameters of attachment of the label to the container are a function of the type of foam container, as well as the type of adhesive. Suitable adhesives include, for example, an aqueous thermal seal coating, quick drying (viscosity: 23-30 seconds # 3zahn at 21 ° C, flash point: none, boiling point: 100 ° C). A specific example of a suitable adhesive for this requirement is Corkote-57CP. According to other embodiments of the present invention, the label 13 is fixed with at least one of the following: a thermal agent, a hot melt coating and a plastic coating. The plastic coating may comprise one or more of the following: polyethylene, polypropylene and any other suitable polymer or copolymer, or mixtures thereof.

In a fourth station 26, the labeled foam containers 15 are removed from the turret 14. Removal can be obtained by techniques well known in the art, such as, for example, by suction.

Reference is now made to Figures 4, 5 and 6. The transfer device 40 of the outer sleeve inserts the label 13 on the unlabeled plastic foam cup 17, which had already been placed on the mandrel 14 in the first station 20. The mechanism illustrated in the figure is shaped for a turntable 44 driven from an intermittent advancing device 45, which, for example, has four positions. The intermittent advancing device 45 is driven by an electrical actuator 46 which may include a gearbox 47. The intermittent advancement device 45 may have four positions. In the 90 ° position the unfolded labels 13 are wrapped in a mandrel 42 by means of two conical-shaped revolution fins 41, 43. The outer sleeve is held in the mandrel 42 by means of a vacuum and the seam of the needle is formed. label 13. Then the rotary table 44 is moved to the 180 ° position to cool the labels 13, and is then moved to the 270 ° position, in which the vacuum is cut and the label 13 is released from the mandrel 42 towards the transfer receptacle 48, horizontally. The label 13 is fixed to the transfer receptacle 48 by vacuum being moved by an air cylinder 51 to rotate the label 13 90 °, in order to place the label 13 on the mandrel 14 in the second station 22, to apply the label 13. to the foam container 17. Vacuum is cut in the receptacle transfer 48 to deliver the label 13 to the foam container 17 in the second station 22.

During operation, a plastic foam container, freshly made, unlabeled, preferably made of EPS), is placed on a mandrel 14 in. the first station 20. The turret 12 is advanced 90 degrees, passing the unlabeled container 17 to the second station 22, where a label 13 is applied to the outer surface of the plastic foam container 17, to form the container 15 foam labeled. The turret 12 is advanced another 90 degrees, sending the plastic foam container with the label 13 unattached, to the third station 24. In the third station the heated cavity 32 is lowered onto the mandrel 14, on which the foam container is placed, in order to surround substantially the outer surface to which the label 13 is applied. The cavity 32 heats the container 17 of plastic foam on the outer surface to which the label 13 is applied, at a temperature and for a time sufficient to attach the label to the outer surface of the foam container 17, and sufficient to prevent shrinkage of the foam container 17, so as to form the labeled foam container 15. The resulting labeled plastic foam container 15 is advanced to the fourth station 26, where it is removed from the turret 12 and the mandrel 14.

According to some embodiments, the cavity 32 heats the plastic foam container 17 on the outer surface to which the label 13 is applied, at a temperature and for a time sufficient for the label is attached to the outer surface of the foam container 17, and sufficient not only to prevent shrinkage, but to expand the foam container 17, so that it attaches to the label 13 so as to form the labeled foam container 15 .

By way of explanation, a container that has been removed from the molding machine tends to shrink because residual blowing agent is expelled from the container, which is replaced by air. When the container is heated in the cavity 32, heating expands the blowing agent remaining in the container, thereby expanding the foam container 17 or at least counteracting the shrinkage. Once the label is applied to the freshly made container, it has the advantage that the label itself retains the shape of the freshly made container, in order to counteract, decrease and / or prevent shrinkage of the container, after the process is completed of labeling.

Various labels 13 can be used with the invention. These include, for example: polypropylene and polyethylene films, paper, coated papers, aluminum or plastic film and metal laminations. It is preferred that the label has good printing characteristics to give an improved aesthetic appearance. One of ordinary skill in the art will understand the types of materials suitable for use on the label for labeled foam containers, in accordance with the present invention.

It will be appreciated that the systems according to the present invention can be modified in many ways. For example, although the machine 10 has been described with reference to the previous figures, with mandrels that are arranged horizontally with respect to their longitudinal axes, that is, in a vertical orientation, it should be understood that the machine can be configured so that the mandrels can be arranged vertically with respect to their longitudinal axes, that is, in a horizontal orientation.

Figure 11 shows a machine 300 for labeling a freshly made plastic foam container 317 according to a second embodiment of the invention. The machine 300 includes, among other elements, a damping attachment 302, a cavity made of a male portion 304 and a female portion 306, a delivery system 308 and an elimination arm 326.

The delivery system 308 comprises a conveyor 310 for the plastic foam container 317, a conveyor 312 for the label 313, an arm 314 for collecting and transporting the plastic container 317 using, for example, a vacuum, an arm 316 for pick up and transport label 313 using, for example, a vacuum. The arms 314 and 316 may be in a single rotating mechanism 318 or in two separate rotating mechanisms (one for the arm 314 and another for the arm 316).

The damper attachment 302 may comprise a containment structure 320, mounted on a suitable structure (not shown) that allows the support and movement of the containment structure described later, for example, using robotic arms. The containment structure 320 may be of sufficient size to contain the label 313 which is already formed as an outer sleeve.

The male portion 304 of the cavity is mounted on a laterally movable platen 322, which is configured for move below the female portion 306 of the cavity. The female portion 306 of the cavity is mounted on a vertically movable structure 324, which is capable of delivering the female portion 306 of the cavity into contact with the male portion of the cavity, so as to form a cavity surrounding the outer surface of the cavity. 317 container of plastic foam on which it sits - label 313.

The operation of the machine 300 will be described below. In Fig. 11 the conveyor 310 supplies the plastic foam container 317 to the arm 314 and the conveyor 312 supplies the label 313 to the arm 316. In Fig. 12A the arms 314 and 316 collect the container 317 and the label 313, respectively, and retract. The arms retain the container and the label using, for example, a vacuum. In Fig. 12B the rotary mechanism 318 rotates the arms 314 and 316 so that the label 313 is aligned with the containment structure 320 of the shock absorber 302. In Fig. 12C the arm 316 is extended so as to place the label 313 within the containment structure 320. The vacuum is cut, so that the label 313 remains in the containment structure 320. The arm 316 is retracted. In this way, the label 313 is placed on the damper attachment 302.

In Figure 12D the rotating mechanism 318 rotates the arms 314 and 316, so that the container 317 is aligned with the containment structure 320 of the shock absorber attachment 302. In Figure 12E the arm 314 is extended so as to position the container. 317 within the containment structure 320 and within the 313 label. the vacuum is stopped so that the container 317 remains on the label 313 in the containment structure 320. In FIG. 12F, the arm 314 is retracted. In this way, the container 317 is positioned within the label 313 in the cushioning attachment 302.

In Figure 12D the rotating mechanism 318 rotates the arms 314 and 316, so that the container 317 is aligned with the containment structure 320 of the shock absorber 302. In Figure 12E the arm 314 is extended so as to position the container. 317 within the containment structure 320 and within the label 313. The vacuum is cut so that the container 317 remains on the label 313 in the containment structure 320. In Figure 12F the arm 314 is retracted. the container 317 is positioned within the tag 313 in the damper attachment 302.

In Figure 12G the rotary mechanism 318 rotates back to its position in Figure 11 and the containment structure 320 is moved, by means of its supporting and moving structure (for example, the robotic arms) in order to place the container 317 and the tag 313 on the male portion 304 of the cavity. In Figure 12H the container 317 and the label 313 are placed in the male portion 304 of the cavity.

In Fig. 121 the containment structure 320 moves back to its position in Fig. 11. In addition, the male portion 304 of the cavity is moved by means of the movable platen 322, in order to move to a position below the 306 female portion of the cavity. In Figure 12J the female portion 306 is lowered onto the structure 324 in a manner that the cavity is positioned to encircle the outer surface of the plastic foam container 317 to which the label 313 is applied.

The cavity heats the plastic foam container 317 on the outer surface to which the label 313 is applied, at a temperature and for a time sufficient to attach the label to the outer surface of the foam container 317, and sufficient to prevent the shrinking the foamed container 317 or to expand the foam container 317, so as to make contact with the label 313. As a result of the bonding, a labeled foam container 315 is formed, as seen in Figure 12K.

The conduction heat transfer, which results in heating of the work piece 30 is caused by the hot oil supplied to the cavity. The heating oil that can be used can include, for example, Seriola 2997 (which has the following properties: specific density at 15 ° C, 0.965, viscosity at 40 ° C, 220 cSt, viscosity at 100 ° C, 5.16 cSt; viscosity index, 80, pour point, -33 ° C, flash point, 300 ° C, total acid number, 0.03 mg KOH / g, and copper corrosion, 1A). Other heating oils can also be used. For example, a heating oil having the following properties can be used: Density at 15 ° C 829 kg / m3 Viscosity at 40 ° C 30.4 mm2 / s Viscosity at 100 ° C 5.91 mm2 / s viscosity index 135 Flash point 234 ° C Pour point -54 ° C Total acid number 0.03 mg KOH / g.

As noted earlier, the application of air pressure or mechanical pressure improves heat transfer, thereby increasing the speed of the machine and the process. The optimum amount of pressure differs, depending, for example, on the size of the vessel / container that needs to be labeled. The application of pressure in the mold also provides additional benefits. For example, during compression of the outer sleeve to the container, the label not only attaches to the container, but is also pressed into the surface of the container. The result is a smoother surface, which is indicative of an injection molding process, in which the label is placed in the mold and the container is formed around it. In other words, there is a more seamless appearance on the label on the container.

The parameters of attachment of the label to the container may include the duration of the temperature, the temperature of the fluid and the pressure applied to the label and to the container. The duration of the application of pressure and temperature may be on the scale of about 1 second to about 10 seconds, preferably about 2 seconds to about 5 seconds, most preferably about 3 seconds. The temperature of the fluid can vary from about 100 ° C to about 140 ° C, preferably from about 115 ° C to about 135 ° C, most preferably around 128 ° C. The applied pressure can vary from about 20 psi (0.137 MPa) to about 100 psi (0.689 MPa), preferably around from 40 psi (0.275 MPa) to around 80 psi (0.551 MPa); very preferable, around 60 psi (0.413 MPa).

The parameters of attachment of the label to the container are a function of the type of foam container, as well as the type of adhesive. Suitable adhesives include, for example, an aqueous thermal seal coating, quick drying (viscosity: 23-30 seconds # 3zahn at 21 ° C, flash point: none, boiling point: 100 ° C). A specific example of a suitable adhesive for this requirement is Corkote-57CP. According to other embodiments of the present invention, the label 313 is fixed with at least one of the following: a thermal agent, a hot melt coating and a plastic coating. The plastic coating may comprise one or more of the following: polyethylene, polypropylene and any other suitable polymer or copolymer, or mixtures thereof.

Once the label is applied to the freshly made container, there is the advantage that the label maintains the shape of the freshly made container in a manner that counteracts, decreases and / or prevents shrinkage of the container after the labeling process is completed. By way of explanation, a container that has been removed from the molding machine tends to shrink because it expels the residual blowing agent from the container, which is replaced by air. When the container is heated in the cavity 32, the heating expands the blowing agent remaining in the container, thereby expanding the foamed container 17 or at least counteracting the shrinkage.

Various labels 313 may be used in the invention. These include, for example, polypropylene films and polyethylene, paper, coated papers, aluminum or plastic film and metal laminations. It is preferred that the label has good printing characteristics to provide an improved aesthetic appearance. Those of ordinary skill in the art will understand the types of materials suitable for use on the label for labeled foam containers, in accordance with the present invention.

In Figure 12K the female portion 306 is lifted in the movable structure 324. In Figure 12L the male portion 304 of the cavity is moved by means of the movable platen 322., so that it moves back to its original position in Figure 11. In Figure 12M the separation arm 326 extends so as to collect the container labeled 315, for example, by vacuum. In Fig. 12N the labeled container 315 is collected outside the male portion 304 of the cavity and rotated or otherwise moved by the separation arm 326, to a point to release it.

An advantage of the invention is its speed and its precision. Modes have been built by modifying conventional machines used to make paper cups. Such machines are particularly suitable for high speed manufacturing, in which a cut paper is wrapped to form the sides of a container, and a bottom portion is formed. Then the container is arranged in a cavity, with its upper portion exposed so that the eyebrow can be formed. However, conventionally, the cavity used to form the eyebrow of a paper cup is not heated.

It has been found that, compared to the machines conventional labellers, the present invention is better suited to apply a label to an area of greater surface area. This is particularly applicable for vessels, such as vessels, which have conical surfaces.

According to a preferred aspect, the invention can be used to manufacture a labeled foam cup, which has excellent aesthetic appearance, while maintaining acceptable cost and acceptable stiffness and barrier characteristics. In particular, the label can have a smooth appearance, due to the pressure of the label inside the container. Thus, the overlapping end portions of the label are imbedded in the vessel, rather than protruding from the vessel.

Figure 7 is a perspective view of a container according to the invention, which is a vessel 200, in this particular example. The cup 200 comprises an inner portion 204, made of a plastic foam, such as EPS. The inner portion 204 defines the shape of the cup 200, which includes a lip 210, a bottom 212 and a side wall 215. An outer sleeve 26 is fixed to the inner portion 214, and the outer sleeve, in this particular example, comprises a paper label with the stylized legend "Coffee" 218. While a glass is shown, it will be appreciated that other types of containers, such as soup bowls, boxes and other containers, can also be provided.

Paper label 216 has excellent printability, compared to ordinary and common foam products. Although a paper label is illustrated in this example, the outer sleeve according to the invention may comprise other suitable materials known in the art, such as metal foils or plastic films. Preferably, the containers according to the invention use paper and / or plastic films with base weights ranging from 17.5 g / m2 to 200 g / m2.

The label 216 is attached to the inner foam portion 214 using a thermal adhesive, in accordance with common and current techniques, known in the art. Other bonding agents, including thermally activated agents, hot melt coatings, plastic coatings (such as polyethylene, polypropylene and other polymers) and other agents known in the art can be used. It is to be noted that the particular binding agent used can increase the total stiffness and the behavior of the container.

According to an aspect of the invention, in which the amount of plastic resin used in the foam portion to which a label is affixed is significantly less than in ordinary plastic foam containers, in size and shape comparable. This is achieved by decreasing the density of the portion of foam to which the label is affixed. Alternatively, the portion of foam to which the label is affixed may have a smaller thickness than ordinary plastic foam containers of comparable size and shape.

Figure 8 is a sectional view of a vessel according to an embodiment of the invention. As illustrated, the wall portion 215 of plastic foam to which the label 216 is affixed has a thickness Wl. It also has a density pl. In this example, Wl is much thinner than the thickness W3 of the wall of a conventional foam cup, as shown in Figure 10.

Figure 9 is a sectional view of a vessel according to another embodiment of the invention. In this example, the wall portion 215 'of plastic foam has a thickness W2 which is comparable to the thickness W3 of a common foam cup, as shown in Figure 10. However, the glass of the Figure 9 has a density p2 that is smaller than the density p3 of a common foam cup, as shown in Figure 10.

Although a thin-walled beaker and a low density foam beaker are shown as separate embodiments, it should be understood that a beaker according to the invention can combine these aspects.

Figure 10 is a sectional view of a common foam cup. The foam cup of FIG. 10 has a capacity and an internal shape similar to those of the cups of FIGS. 8 and 9. Fixed to the walls is an optional label 216. The wall 214 of the common foam cup has a thickness W2 and a density p2.

Due to the lower relative density and / or lower relative thickness of the portion that is covered by the outer sleeve, the containers according to the invention use less resin than a common foam container of comparable size and shape.

An effective scale of densities for the wall of the internal foam portion of a container - molded foam, labeled, final, according to the invention (which have capacity from 4 ounces (118.28 mL) to 175 ounces (5,174 L)) is less than about 0.08 g / cm3 or, more preferable, about 0.0410 to 0.0759 g / cm3.

Thinner or less dense foam containers, without outer sleeve, have a significantly reduced total stiffness. They are also the thinner or less dense foam containers more susceptible to permeation by the materials that are put in the container. However, it has been found that the use of the appropriate outer sleeve compensates for the reduction in stiffness and improves the barrier properties. The provision of an outer sleeve constituted by a suitable material, such as paper, provides an improved printing capacity.

From the foregoing it should be apparent to those of ordinary skill in the art that the present invention provides labeled containers / cups which have the following advantages: cost efficiency, high quality printing capacity, sufficient stiffness, insulating and barrier properties, minimum amount of raw material and efficient stacking. In particular, the present invention provides substantial cost savings, through the use of lower amounts of resin, compared to common foam containers and currents that provide comparable performance.

Even though the invention has been described with reference to specific embodiments and examples, those of ordinary skill in the art will appreciate that the present invention can be incorporated in other forms, without departing from the spirit or scope of the invention. Therefore, the modalities described herein must be considered, - - in all respects, illustrative and not restrictive.

Claims (17)

1. - A method for manufacturing a labeled plastic foam container comprising the following steps: applying an outer sleeve to an outer surface of a portion of unlabeled plastic foam that is capable of substantially shrinking if left unheated; heating a workpiece using a hot oil that is supplied within the interior of the workpiece by defining the workpiece a cavity having a bottom wall and a side wall so as to correspond in shape with the outer surface of the portion of plastic foam; placing the work piece so that the cavity surrounds the outer surface of the portion of plastic foam to which the outer sleeve is applied; heating the outer surface of the plastic foam portion to which the outer sleeve is applied with the cavity by heat transfer by conduction from the workpiece to the outer surface of the plastic foam portion while the foam portion of the plastic is disposed within the cavity, at a temperature and for a sufficient time to attach the label to the outer surface of the plastic foam portion and sufficient to prevent shrinkage of the plastic foam portion to provide a foam container of labeled plastic, being the heat transfer by conduction caused by the hot oil that is inside the work piece; Y Remove the labeled plastic foam container.

2. The method according to claim 1, wherein the outer sleeve has an outward facing surface to which a printing or graphic designs are applied, and wherein the outer sleeve provides rigidity to the plastic foam portion.

3. - The method according to claim 1, wherein the labeled plastic foam container has an overall density in the range of 0.05720 to 0.1888 g / cm3 in the final state.

4. - The method according to claim 1, wherein the plastic foam portion defines a cup shape with a lip portion, a bottom portion and a side wall.

5. - The method according to claim 1, wherein the plastic foam portion comprises EPS.

6. - The method according to claim 1, wherein the outer sleeve comprises at least one of the following: a metal foil, a plastic film and an outer paper sleeve.

7. - The method according to claim 1, wherein the outer sleeve is fixed to the plastic foam portion with at least one of the following: a thermal agent, a hot melt and a plastic coating.

8. - The method according to claim 7, wherein the plastic coating comprises at least one of polyethylene or polypropylene.

9. - The method according to claim 1, wherein the plastic foam portion is capable of undergoing shrinkage if left unheated when the plastic foam portion is surrounded by the cavity.

10. - The method according to claim 1, wherein the cavity is heated to a temperature in the range of 135 ° C to 150 ° C.

11. - The method according to claim 1, further comprising applying pressure to the outer surface to which the outer sleeve is seated with the cavity.

12. - The method according to claim 1, wherein the outer sleeve is placed in a damping attachment, the plastic foam portion is placed inside the outer sleeve in the damping attachment, the outer sleeve and the foam portion are placed of plastic on a male portion of the cavity and the male portion of the cavity is placed within a female portion of the cavity so that the cavity is positioned to surround the outer surface of the plastic foam container to which the cavity is applied. outer sleeve.

13. - The method according to claim 1, wherein the portion of plastic foam, before the application of the outer sleeve, is a freshly made container that has been formed less than 21 days before the application of the outer sleeve.

14. - The method according to claim 1, wherein the portion of plastic foam, before the application of the outer sleeve, is a freshly made container that has been formed less than 10 days before the application of the outer sleeve.

15. - The method according to claim 1, wherein the portion of plastic foam, before the application of the outer sleeve, is a freshly made container that has been formed less than 5 days before the application of the outer sleeve.

16. - A labeled plastic foam container manufactured in accordance with the method of claim 1.

17. - The container in accordance with the claim 16, wherein said labeled plastic foam container has an overall density in the range of 0.05720 to 0.1888 g / cm3.