JP4723363B2 - Insulated container, method for producing the same, and laminated label used in this method - Google Patents

Description

The present invention relates to a synthetic resin heat insulating container having a heat insulating structure and having a clearly printed surface, a method for manufacturing the same, and a laminated label used for manufacturing the heat insulating container.

Plastic containers with high-temperature contents have a hot outer surface that is difficult to hold with bare hands and may cause burns. On the other hand, the contents of the container often need to be kept as long as possible. For this reason, various containers with heat insulation means are known.
For example, Japanese Patent Application Laid-Open No. 7-291250 discloses a heat insulating container in which a fiber sheet or a nonwoven fabric is bonded to the outer surface of the container as a heat insulating material, or a side wall of the container having a double wall structure having a gap inside. Yes.
In addition, in the market, a heat insulating container is generally used in which a laminated label obtained by adhering a heat shrinkable synthetic resin film such as PET (polyethylene terephthalate) to one or both sides of a nonwoven fabric is adhered to the outer surface of the container. Some are printed.

Among this type of conventional heat insulating container using a non-woven fabric, the one with the non-woven fabric exposed is molded resin enters the gap through the non-woven fabric layer when in-mold molding is performed together with the container body, and the heat insulation is not exhibited.
In addition, since the non-woven fabric bonding surface is not flat, as described above, the conventional laminated label that directly bonds the plastic film to the non-woven fabric with the adhesive has a problem that the non-woven fabric and the plastic film have insufficient bonding strength and are easily peeled off. was there.

Above all, the conventional heat insulating container has a large contact surface when it is held in the hand because the heat insulating label surface outside the container is uniformly flat. For this reason, the heat insulating effect is only the thickness of the nonwoven fabric, and a sufficient heat insulating effect was not obtained.

Furthermore, the heat-insulated container formed by in-mold molding with the printed plastic film bonded to the nonwoven fabric as the container heat-insulating material causes fine wrinkles in the printed film because the nonwoven fabric shrinks as the container body cools, The sharpness of printing was not always sufficient.
In addition, products made by laminating printed non-stretched plastic films on non-woven fabrics by heat-sealing have inaccurate printing pitch, so that the position accuracy of labels and printing design is kept constant, and beautiful gravure printing clarity is maintained. It was difficult.
JP-A-7-291250

Accordingly, a first object of the present invention is to provide a heat insulating container in which the heat insulating effect is remarkably improved and a clear printed display is maintained.

The second object of the present invention is to provide a method for producing the above-mentioned heat insulating container.

The third object of the present invention is to provide a heat insulating laminated label for a container for use in the heat insulating container and the method for producing the same.

In order to achieve the first object, the heat insulating container of the present invention is a synthetic resin in which a plastic film layer is laminated on both the front and back surfaces of a nonwoven fabric by thermal fusion (thermal lamination) and a number of embossments are formed on one surface. The monolithic nonwoven fabric is composed of an integral laminate label in which a plastic film layer printed on the inner side surface or the outer side surface is laminated on either the front or back surface of the nonwoven fabric raw fabric, and a thermoplastic container formed by injection molding. The label is heat-sealed to the outer surface of the container at the same time as the injection molding of the container with the printing film facing outside, thereby forming a large number of hollow irregular surfaces due to the embossing of the nonwoven fabric laminate material on the label surface outside the container. In addition, a plurality of local voids are formed inside the laminated label.

A film in which an inorganic oxide such as aluminum oxide or SiOx is vapor-deposited may be further laminated between the plastic film layer and the printing film layer of the raw nonwoven fabric.

In order to achieve the second object, a method for manufacturing a heat insulating container according to the present invention comprises a laminated film in which a plastic film is superimposed on both front and back surfaces of a nonwoven fabric, a flat roll, and an embossing roll having a number of protrusions formed on the surface. A non-woven fabric laminate sheet is formed by heat-sealing by thermocompression bonding to form a large number of irregularities on one surface and a smooth surface on the other surface. A plastic film having an inner surface or an outer surface printed thereon is laminated on any one surface with an adhesive to form an integral laminated sheet composed of the nonwoven fabric laminated sheet and the printed plastic film. This label is pressed into the inner side of the mold cavity of the container injection molding so that the printed plastic film is on the outside, and the injection molding is performed. After injection molding by injecting hot-melt material of the thermoplastic of the container body between the label and the mold core in the mold, characterized by cooling.

In any case, preferably, the monolithic laminated label is formed by laminating a non-stretched polypropylene film on both front and back surfaces of a nonwoven fabric made of polypropylene fibers by heat-sealing, and two printed plastic film layers are provided. An axially stretched polypropylene film is laminated, and the thermoplastic container is made of polypropylene.

In order to achieve the above third object, the heat-insulated laminated label for container in-mold molding of the present invention is formed by laminating a plastic film layer on both the front and back surfaces of a nonwoven fabric by heat fusion and forming a large number of embossments on one surface. It is characterized in that a plastic film layer printed on the inner side surface or the outer side surface is laminated on either the front or back side of the synthetic resin nonwoven fabric raw fabric.

In addition to the heat insulating property of the nonwoven fabric layer of the laminated label, the heat insulating container of the present invention is formed with uneven embossing on the outer surface of the container, so that the contact surface when held by hand is small and local, Since a void due to shrinkage after injection molding is also formed inside the laminated label, the heat insulating effect is remarkably improved, and a heat insulating container that is gentle to the hand and excellent in heat retaining action can be obtained.

Since the film layer is interposed between the container main body and the nonwoven fabric layer, the nonwoven fabric layer is not crushed and the molten resin does not enter during container injection molding.

Since in-mold labeling is performed at the same time as the injection molding of the container, the labeling process is omitted, and the in-mold labeling of the laminated label can be performed also on the side surface of the container body having a concavo-convex shape. Therefore, since the non-woven fabric has good followability with respect to the container shape, it does not easily become wrinkles and does not peel off.

By laminating the printed biaxially stretched plastic film layers in a bonded state, a laminated label with excellent printing pitch accuracy and beautiful gravure printing can be obtained. Further, an oxygen barrier property is imparted to the container by further laminating a film on which an inorganic oxide such as aluminum oxide or SiOx is deposited between the plastic film layer and the printing film layer of the raw nonwoven fabric.
Therefore, by using these laminated labels, an in-mold container having a light shielding property and an oxygen barrier property can be obtained, whereby a container having a heat insulating property, a light shielding property, and a barrier property can be obtained.

Embodiments of the present invention will be described below with reference to the accompanying drawings.
As shown in FIG. 1, the heat insulating container 1 of the present invention is formed by integrally injecting the molten synthetic resin of the container body 3 in-mold with the laminated label 2 described in detail later on the outside. Due to the in-mold injection molding of the structure and the container body 3, the outer surface of the laminated label 2 that is integrally heat-sealed to the outside of the container 1 is formed on the uneven surface, and the inside of the laminated label 2 after the container injection molding A plurality of local voids described later are incorporated.

2 and 3 show an enlarged cross section of the laminated label 2 before in-mold molding used in the heat insulating container 1 according to the present invention. The laminated label 2 is an unstretched plastic film layer on both the front and back sides of the nonwoven fabric 4. 5 and 6 (made of polypropylene) are laminated by heat-sealing, and a non-woven fabric raw fabric 7 having a rough surface by forming a large number of embosses on either the front or back surface is used as a base material. A printed plastic film layer 9 (made of polypropylene) having a printing layer 8 such as gravure printing on the inner surface is provided on one side (7) (an uneven surface in the embodiment of FIG. 2 and a flat surface in the embodiment of FIG. 3). It is the structure laminated | stacked through the.

If the thickness of the nonwoven fabric 4 is too thin, the heat insulation effect is low, and if it is too thick, there is a problem in the container production process. Therefore, a polypropylene spunbond nonwoven fabric having a basis weight of about 50 to 150 g / m ² is preferably used.
Moreover, the plastic film layers 5 and 6 laminated | stacked by heat sealing | fusion on the front and back both surfaces of this nonwoven fabric 4, Preferably an unstretched polypropylene film about 20-30 micrometers is used.
The reason why the non-stretched polypropylene film layer is laminated on the inner side (container side) of the nonwoven fabric 4 is that when the nonwoven fabric 4 is exposed, the molten resin in the container is formed into four layers of the nonwoven fabric during in-mold injection molding of the inner container resin. This is because the heat insulation properties are hindered by entering the inside, and the reason why the layers are laminated by heat fusion is to improve the lamination strength with the printing film layer 9 and prevent peeling.

On the other hand, the printed plastic film layer 9 laminated on either the front or back surface of the non-woven fabric 7 is preferably configured to print on the inner surface of a biaxially stretched polypropylene film of about 20 to 30 μm. The printed surface is laminated on the surface of any one of the plastic film layers 5 and 6 of the raw nonwoven fabric 7 via the adhesive layer 10 with the adhesive layer 10 interposed therebetween.
In the embodiment of FIG. 2, the uneven plastic film layer 5 of the nonwoven fabric original fabric 7 is placed outside, and the printed plastic film layer 9 is laminated on this surface with an adhesive. On the contrary, as shown in FIG. Further, the printed plastic film layer 9 may be laminated with the adhesive layer 10 with the flat side plastic film layer 6 of the nonwoven fabric 7 being the outside.
In the embodiment shown in the figure, the case where an adhesive is applied as the laminating means is illustrated, but the present invention is not limited to this. For example, a melt synthetic resin extrusion laminating means may be used.

The reason why the biaxially stretched polypropylene film layer 9 printed on the inner surface is laminated on the outer surface of the nonwoven fabric 7 with an adhesive or the like is that it is printed on a biaxially stretched polypropylene film excellent in pitch accuracy and beautiful gravure printing This is to generate a label with a mark. In other words, a laminated label in which a non-stretched polypropylene film is printed and laminated by heat fusion has poor print pitch accuracy, and the position of the print design relative to the label does not fall within a predetermined range.

FIGS. 4 to 9 show an example of the manufacturing process of the laminated label 2 used for in-mold injection molding of the heat insulating container 1 of the present invention. First, as shown in FIG. The non-stretched plastic film fed from the second feed roll 13 is superposed on the upper surface of the non-stretched plastic film layer 6 and the non-woven fabric 4 supplied from the non-woven fabric feeder 12. In the process of winding up and transporting the three-layer sheet in which the layers 5 are stacked and the non-stretched plastic film layers 6 and 5 are sandwiched between the front and back of the nonwoven fabric 4 sheet, the flat roll 14 and the embossing roll 15 are pressed against each other. Then, heat fusion lamination by thermocompression bonding is performed, and the nonwoven fabric is processed into a nonwoven fabric 7 and wound around a winder 16.

As shown in FIG. 5 in an enlarged manner, the embossing roll 15 is a rotating body having an outer peripheral surface formed on a number of concave and convex surfaces, while the flat roll 14 is a rotating body having a smooth outer peripheral surface and both are a plastic film layer 5, 6 to the fusing temperature. Therefore, as shown in an enlarged view in FIG. 6, the unwinding plastic film layers 5 and 6 are fused and laminated on the front and back of the nonwoven fabric 4 on the winder 16 by thermocompression bonding, and one side is provided by the embossing roll 15. The raw nonwoven fabric 7 formed on the uneven surface and flat on the other surface is wound up.

Next, as illustrated in FIG. 7, the printed plastic film layer 9 fed out from the feeding machine 17 of the biaxially stretched plastic film layer 9 that has been printed and wound up on the inner surface is passed through the adhesive coating machine 18 to the printing surface. After the adhesive is applied, the adhesive is dried and pulled out through a dryer 19 using a dryer or the like.
On the other hand, the nonwoven fabric web 7 wound on the winder 16 is fed from the nonwoven fabric web feeding machine 20, and the printed plastic film layer 9 subjected to the adhesive coating process is set with the printing layer 8, that is, the adhesive layer 10 inside. Then, the adhesive rollers 21 and 21 are pressed against each other and bonded and laminated (dry lamination). The laminated sheet 22 having the laminated structure shown in FIG. 2 or 3 is generated and wound around the winder 23.

Next, as shown in FIG. 8, the laminated sheet 22 is punched into the laminated label 2 having a desired shape in accordance with the side development of the container, and the both ends of the punched laminated label 2 are banded to form a laminated label. The second cylindrical body 24 is formed.

Finally, as shown in FIG. 9, the cylindrical body 24 of the laminated label 2 is supplied inside the cavity 26 of the mold 25, and the container body is melted between the cylindrical body 24 of the laminated label 2 and the mold core 27. By injecting polypropylene resin and injection molding, the heat insulating container 1 of FIG. 1 is obtained in which the laminated label 2 is integrally heat-welded to the outer surface of the container body 3 by heat fusion.

The heat insulating container 1 of the present invention in which the cylindrical body 24 of the laminated label 2 is in-mold molded at the same time as the container injection molding as described above is obtained after the injection molding by the laminated structure of the laminated label 2 and the in-mold molding of the container body 3. The following phenomenon appears in the internal structure of the laminated label 2.
That is, as shown in FIG. 10, the container body 3 shrinks and becomes smaller due to cooling after injection molding. At this time, the heat-sealed plastic film layer 6 (in the case of FIG. 2) of the nonwoven fabric raw fabric 7 heat-sealed to the container body 3 follows the container body 3 and shrinks. Since the thin fibers of the nonwoven fabric 4 are overlapped, there is a lot of space in the cross section, and it does not shrink because it is not firmly bonded to the plastic film layer 6.
Therefore, each layer from the nonwoven fabric 4 to the outermost inner surface printed plastic film layer 9 becomes a buffer wall, ie, the nonwoven fabric 4 layer, the heat-sealed plastic film layer 5, the adhesive layer 10, and the printing layer 8 Since the printed plastic film layer 9 does not follow the shrinkage of the container body 3, the outer surface of the heat insulating container 1 becomes the uneven embossed surface 28 as shown in FIG.

That is, the cross-section of the four layers of the nonwoven fabric is an aggregate in which fine fibers are originally overlapped and there are voids inside, so that the coarse fiber density becomes somewhat dense due to the shrinkage of the container body 3, so that there is no significant unevenness change. Since the outer layers are plate-like, when the container body 3 and the plastic film layer 6 laminated on the container body 3 are contracted, there is no place to go, and the embossed surface 28 is clearly deformed.

On the other hand, since the interface between the outer plastic film layer 5 and the upper surface, that is, the adhesive layer 10 of the four nonwoven fabric layers is not a strict flat surface, the outer plastic film layer 5 and the adhesive layer 10 are completely bonded to each other. It has not been. For this reason, due to the shrinkage after the injection molding, a plurality of local voids 29 are formed between the adhesive layer 10 and the outer unstretched plastic film layer 5 facing the adhesive layer 10.

In addition, the cross section of the nonwoven fabric 4 layer is originally a porous one having a gap 30 between the fibers. However, the present invention further includes the nonwoven fabric 4 layer and the plastic film layer 5 or 6 on the embossed side only of the embossed recess. Since it is merely heat-sealed, a plurality of local voids 31 are also generated between the nonwoven fabric 4 layer and the unstretched plastic film layer 5 or 6 on the embossing side due to the shrinkage of the container body 3 after injection molding, The heat insulation effect is more effectively exhibited.

Although not shown in the drawings, as described above, an inorganic oxide such as aluminum oxide or SiOx is deposited between the plastic film layer 5 or 6 and the printed film layer 9 on at least one surface of the nonwoven fabric 7. May be laminated to give oxygen barrier properties to the container.

In the embodiment shown in the figure, the printing layer 8 is applied to the inner surface of the biaxially oriented polypropylene film layer 9, but the printing layer 8 may be applied to the outer surface of the film layer 9 on the contrary. .
Moreover, in the Example, although the case where the film layer 9 which performed printing was laminated | stacked on the film layer 5 or 6 of the nonwoven fabric raw fabric 7 using an adhesive agent was illustrated, not only this but it laminate | stacks with another joining means. Also good.

Since the heat insulation property of the container is greatly improved, the present invention is a hand-insulated container that is hand-friendly when used as a container for pouring hot tea or coffee, or as an instant food or beverage container for heating the contents in a range or the like. Can be widely used industrially.

In addition, since the printed surface is kept clear, the appearance is beautiful, and the distinguishability of over-the-counter products is improved, contributing to sales promotion.

Furthermore, since even fine characters are clearly displayed, when used for food containers, it becomes easier to see the contents table of ingredients, materials, precautions, etc., and the convenience of producers and consumers is improved.

Partially cutaway side view of an insulated container according to the present invention The expanded sectional view of the lamination label used for the heat insulation container of the present invention The expanded sectional view of the lamination label by other examples of the present invention. Manufacturing process diagram of nonwoven fabric Embossing roll enlarged cross-sectional view Schematic enlarged cross-sectional view of the nonwoven fabric Manufacturing process diagram of laminated label Manufacturing process diagram of laminated label Insulated container injection molding process diagram Partial enlarged sectional view of the side wall of the insulated container after container injection molding

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Thermal insulation container 2 ... Laminated label 3 ... Container main body 4 ... Nonwoven fabric 5, 6 ... Unstretched polypropylene film layer 7 ... Laminated nonwoven fabric 8 ... Printed layer DESCRIPTION OF SYMBOLS 9 ... Biaxially-stretched polypropylene film layer 10 ... Adhesive layer 11, 13 ... Feeding roll 12 ... Nonwoven fabric feeding machine 14 ... Flat roll 15 ... Embossing roll 16 ... Winding Take-off machine 17 ... Feeding machine 18 ... Adhesive coating machine 19 ... Dryer 20 ... Non-woven fabric web feeding machine 21 ... Adhesive roller 22 ... Laminated sheet 23 ... Winding Machine 24 ... Laminated label cylinder 25 ... Mold 26 ... Cavity 27 ... Core 28 ... Concavity and convexity embossed surfaces 29, 30, 31 ... Gaps

Claims (6)

  A plastic film layer was laminated on both the front and back sides of the nonwoven fabric by thermal fusion, and a large number of embosses were formed on one side. An integrated laminated label in which a plastic film layer is laminated and a thermoplastic container formed by injection molding, and the integrated laminated label is formed on the outer surface of the container at the same time as the injection molding of the container with the printing film facing outside. It is heat-sealed so that a number of hollow irregularities resulting from embossing of the nonwoven fabric laminate material are formed on the label surface outside the container, and a plurality of local voids are formed inside the laminate label. Insulated container   Between the front and back sides of the nonwoven fabric, a plastic film layer was laminated to form an emboss, and between the plastic film layer of the nonwoven fabric and the printed film layer, a film on which an inorganic oxide such as aluminum oxide or SiOx was deposited was further laminated. The insulated container according to claim 1   The monolithic laminated label is formed by heat-sealing unstretched polypropylene film on both sides of a nonwoven fabric whose nonwoven fabric is made of polypropylene fiber, and the printed plastic film layer is formed by laminating a biaxially stretched polypropylene film. The heat insulating container according to claim 1, wherein the thermoplastic container is made of polypropylene.   A laminated film in which plastic films are laminated on both the front and back sides of a nonwoven fabric is heat-sealed by thermocompression bonding between a flat roll and an embossing roll having a large number of protrusions on the surface to form a large number of irregularities on one surface. In addition, a non-woven fabric laminated sheet having the other surface formed as a smooth surface is produced, and a plastic film having an inner surface or an outer surface printed thereon is laminated on either the uneven surface or the smooth surface of the non-woven fabric laminated sheet. An integral laminate sheet comprising the nonwoven fabric laminate sheet and the printed plastic film is formed, and the integral laminate sheet is punched into a label having a desired shape, and the label is placed on the inner side of the mold cavity for container injection molding, and the printed plastic film is disposed on the outer side. The thermoplastic resin in the container body is pressed between the label in the injection mold and the mold core. After injection molding by injecting fusing material, manufacturing method of the heat insulating container, characterized by cooling   The non-woven laminate sheet of the integral laminate sheet is obtained by heat-sealing unstretched polypropylene film on both front and back surfaces of a nonwoven fabric made of polypropylene fibers, and the printed plastic film layer is formed by laminating a biaxially stretched polypropylene film. The method for manufacturing a heat insulating container according to claim 4, wherein the material of the thermoplastic container is polypropylene.   A plastic film layer was laminated on both the front and back sides of the nonwoven fabric by thermal fusion, and a large number of embosses were formed on one side. Laminated label for the production of insulated containers, characterized by laminating plastic film layers

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