JP5446912B2 - Lid material - Google Patents

Description

  The present invention relates to a heat-sealing lid for a food cup-type container, and more particularly to a lid made of paper and resin, excluding a metal foil such as an aluminum foil from the layer structure.

  Conventionally, as a lid for a food cup-type container, for example, a heat-sealing lid having a laminated structure of paper / polyethylene resin layer / aluminum foil / polyethylene resin layer / hot melt layer is generally used. An aluminum foil is used for the lid member having this configuration in view of its rigidity, plastic deformability, or curl prevention.

  In addition, as a lid material having a configuration in which an aluminum foil is not used, for example, paper / adhesive or polyethylene resin layer / biaxially stretched plastic film layer / polyethylene resin layer / hot melt layer is known.

  As described above, the lid member configured using an aluminum foil can suppress the occurrence of curling due to the rigidity and plastic deformability that are the characteristics of the aluminum foil. In addition, this lid is attached to a cup-type container as a heat-sealing lid, and when eating the contained food, it is opened so that a part of the lid is raised, hot water is poured, and the lid is closed. Some products are eaten after the food in the container is steamed. In this type of product, aluminum foil is used as a part of the layer structure for the lid material, so it has excellent advantages such as partial opening of the lid material when pouring and excellent resealability when it is returned. Have The property of holding the folded shape when folded and maintaining the expanded shape when spread is called dead hold property.

  On the other hand, however, it is not possible to inspect metal contamination with a metal detector after filling the contents in the product production line, and the product purchaser can also heat microwave cooking that has recently been attracting attention other than cooking by pouring hot water. Absent. In addition, the manufacturing cost of the lid material is also high, and there is a problem that the waste after use is incinerated with burning.

  In addition, the lid material of the aluminum-less structure that does not use the latter aluminum foil eliminates the disadvantages of using the aluminum foil, but conversely loses the advantages of using the aluminum foil and easily causes curling. However, the lid material used for the product that steams food by adding hot water has a problem that the opening property by folding the lid material and the resealability by returning the lid material are lowered and the dead hold property is lost.

  In contrast, attempts have been made to improve the performance of the aluminum-less cover material by using materials and post-processing. For example, as shown in Patent Document 1, it extends in a direction orthogonal to the peeling direction of the opening tab. There is also an attempt to improve the above problem by providing a linear adhesive portion.

  Known documents are shown below.

JP 2002-193314 A

  The effect of partially providing an unadhered portion in the adhesive layer between the paper layer and the base film layer is that the paper single layer can be easily folded. Providing the adhesive layer in a continuous line shape effectively exhibits the dead hold property due to the bending effect of the entire unsealed portion as compared with the method of providing the unbonded portion only at the folded portion at the time of opening. In addition, when an unadhered part is provided in the bent part, it is necessary to align with the pattern printing provided on the surface of the paper base material, and it becomes difficult to manage during processing. The process of providing the is easier to manage during the process and has a greater effect.

  However, the line as in Patent Document 1 represents an intermediate density by collecting an infinite number of straight lines (print dictionary: edited by the Japan Printing Society), and in particular, the thickness of the line, the interval in the document, The thickness of the adhesive layer is not limited. When the dry lamination method is used as a general-purpose bonding method, the bonding thickness is as thin as 1 to 6 μm, and there is not enough space for the paper single layer to bend between the paper and the base film. Sex is not demonstrated. Further, even when the distance between the lines provided by the adhesive layer is extremely narrow, the area where the paper single layer is bent is insufficient, and the dead hold property is not exhibited.

  Also, regarding the thickness of the bonding line, if it is excessively thick, the unbonded part contained in the unsealed part will be insufficient, resulting in insufficient dead hold properties. Insufficient strength causes problems such as delamination and substrate tearing during processing or opening.

  From the above, limiting the thickness, width, and interval of the adhesive layer is essential for putting this technology to practical use, and if these restrictions are provided, the processing technique for providing the adhesive layer is also limited. It is.

  The present invention incorporates improvement measures by limiting the thickness, width, interval, and processing method of the adhesive layer provided in a linear form, which is insufficient in the prior art, and intends to solve the above problems widely. Therefore, the purpose is to remove the metal such as aluminum foil from the constituent material of the cover material, and to make it mainly made of paper and resin, so that inspection by a metal detector and microwave cooking is possible. Provides a highly heat-sealing lid material with excellent overall performance that improves disposal after use and is excellent in opening retention of the lid material and resealability by returning it when opened. There is to do.

The present invention has been made in view of the problems, and the invention of claim 1 is a lid member for sealing an upper end opening of a container body, and is formed of a laminate not including a metal layer, and the container body. A lid body that is substantially the same type as the outer peripheral edge of the upper end opening and an opening tab that extends outward from the outer peripheral edge, and the laminate is a paper layer, an adhesive layer, and a base film layer from the outer surface. The adhesive layer is a plurality of linear thermoplastic resin layers extending in a direction perpendicular to the peeling direction of the opening tab, and the basis weight of the paper layer is 50 to 150 g / m ² , and a cover material characterized in that the intermediate peak of 45 ° peel evaluation according to JIS-S0022 when the cover material sealed to the container body is peeled from the container body is 1.5 N or more. .

  By adopting the above-described configuration, when the peeling tab is opened with the opening tab, the paper layer is easily folded at the non-adhesive portion other than the linear adhesive portion, and the dead hold property is expressed in the lid member. . Further, by limiting the basis weight of the paper layer, it is possible to obtain an appropriate dead hold property, suitability for squeezing a product to be stored in a sheet, and bendability at the time of opening. Further, by limiting the peel strength, it is possible to provide a force to bend the paper layer due to the ironing effect on the paper layer at the time of opening while maintaining sealing performance and opening suitability, and to maintain an appropriate opening state.

  The invention according to claim 2 is the lid according to claim 1, wherein the plurality of linear thermoplastic resin layers have a line width of 1 to 20 mm and a distance between the lines of 1 to 10 mm. is there.

  As described above, by limiting the line width, the adhesive strength between the paper layer and the base film layer can be sufficiently maintained, and the dead hold property can be appropriately maintained. Further, by limiting the distance between the lines, it is possible to secure a width necessary for the paper single layer to be bent. When the line width is excessively large, the unbonded portion is insufficient, so that the dead hold property is insufficient, and when the line width is too thin, the adhesive strength between the paper layer and the base film layer is insufficient.

  The invention according to claim 3 is characterized in that the base film layer is a biaxially stretched polyethylene terephthalate film having a thickness of 5 to 15 μm or a layer of a biaxially stretched polystyrene film. It is.

  Since the base film layer is limited as described above, the dead hold property is not impaired, the heat resistance in this application is sufficient, the flat property is obtained, and excellent physical properties are obtained as a lid. In addition, there is printing or laminating suitability due to good wettability and high workability. Moreover, even if the contents are oil-based food, it is oil-resistant and is suitable for light-shielding printing.

  According to a fourth aspect of the present invention, the thickness of the plurality of linear thermoplastic resin layers is 3 to 30 μm, and the thermoplastic resin is low density polyethylene, linear low density polyethylene, polypropylene, ethylene-vinyl acetate copolymer. The lid material according to any one of claims 1 to 3, wherein the lid material is a resin mainly composed of at least one of a coalesced resin, an ethylene / acid copolymer resin, and a synthetic rubber.

  The said structure limits the thickness and material of a thermoplastic resin layer. By limiting the thickness of the adhesive layer, the gap between the paper layer of the non-contact portion and the base film layer necessary for bending the paper layer can be sufficiently obtained. In addition, if a resin layer mainly composed of at least one of PE, EVA, ethylene and acid copolymer resin, and synthetic rubber is used as a hot melt agent, an extruded resin layer, and a non-solvent laminating adhesive, it is easy to process, Adhesiveness is also sufficiently obtained. In order to obtain the resin thickness, it is necessary to form an adhesive layer with these resin layers.

  The invention of claim 5 is characterized in that the thermoplastic resin layer is laminated by any one of melt extrusion processing, hot melt spray processing, hot melt gravure coating, hot melt extrusion processing, and non-solvent lamination gravure processing. The lid material according to any one of claims 1 to 4.

  Since the thermoplastic resin layer is laminated by the laminating means, the thickness of the thermoplastic resin layer can be sufficiently taken, and a gap for folding the paper layer between the paper layer and the base film layer can be taken.

  The lid material of the present invention does not have a metal layer such as aluminum foil, can be inspected by a metal detector and cooked in a microwave oven, has improved disposal after use, and has a lid material when opened. Excellent opening retention and resealability due to its return.

It is sectional drawing to which one part of one Embodiment of the container and the lid | cover material of this invention sealed to it was expanded. It is explanatory drawing which looked at one Embodiment of the cover material of this invention from the top. It is sectional drawing to which a part of other embodiment of the container and the lid | cover material of this invention sealed to it was expanded.

  Hereinafter, modes for carrying out the present invention will be described.

  FIG. 1 is an enlarged cross-sectional view of a portion of an embodiment of a container and a lid material of the present invention sealed thereto. Specifically, it is a cross-sectional view cut perpendicularly from the tip of the opening tab of the lid to the opposite end of the outer periphery of the lid. Moreover, FIG. 2 is explanatory drawing which looked at one Embodiment of the cover material of this invention from the top.

  As shown in FIG. 1, the lid member 10 has an opening peripheral edge 21 of the container body 20 so as to seal a circular upper end opening of the cup-shaped container body 20 whose diameter is increased in a tapered shape upward. In addition, the outer periphery of the lid member 10 is joined by being peelable by heat sealing. And it opens by peeling from the container main body 20 in the peeling direction P, holding the opening tab 6 at the left end of the figure.

  The opening tab 6 is preferably arranged in a direction perpendicular to the grain of the paper layer 1 (longitudinal direction of the fibers of the aligned paper). As a result, it is easy to bend along the paper and the folded lid is difficult to return. In addition, forming a concavo-convex pattern on the surface of the lid member can reduce repulsion due to paper fibers, and can further improve the dead hold property at the time of opening.

  As shown in FIG. 1, the lid 10 is a layer in which a paper layer 1, an adhesive layer 2 made of a linear thermoplastic resin layer, a base film layer 3, and a sealant layer 4 made of a thermoplastic resin are integrally laminated. The part which consists of a laminated body which has a structure, and does not have a linear thermoplastic resin layer between the paper layer 1 and the base film layer 3 becomes the space | gap 5. FIG.

  Then, the laminated body is punched out to form a single-piece lid having a circular lid material body and an unsealing tab 6 projecting outward from the outer periphery thereof as shown in FIG. This is material 10.

  FIG. 2 is an explanatory view of an embodiment of the lid member of the present invention as viewed from above, and the left side of the figure. The paper layer 1 is visible, and the right side shows a state where the paper layer 1 is peeled off. On the right side after the paper layer 1 is peeled off, an adhesive layer 2 made of a linear thermoplastic resin layer on the base film layer 3 is visible.

  The adhesive layer 2 is composed of a plurality of linear thermoplastic resin layers extending in a direction O perpendicular to the peeling direction P of the opening tab 6. The extending direction O of the plurality of linear thermoplastic resin layers is matched with the direction K of the paper grain. The plurality of linear thermoplastic resin layers are provided with a line width X and a line-to-line interval Y.

The paper layer 1 preferably has at least a white surface and suitable for multicolor printing, and has a basis weight of both art paper, one art paper, or both coated paper and one coated paper on which a base coat layer for printing is laminated. it is preferable to use a ^{50g / m 2 ~150g / m 2} .

When the basis weight is less than 50 g / m ² , the rigidity and mechanical strength are slightly insufficient. When the basis weight is more than 150 g / m ² , the rigidity is already sufficient and there is no need for more, and time is required for heat sealing. This is not preferable because there is a decrease in the interlaminar strength of the paper and a decrease in the ease of folding of the paper when opened.

  The lid 10 is based on a paper having at least an upper surface (surface opposite to the container) and a base coat layer for printing laminated thereon, and a pattern ink layer of characters, patterns, gloss varnish, etc. on the upper surface side. May be printed, and a paper layer 1 may be formed by laminating a light-shielding ink layer for protecting the contents on the opposite side. Further, the light-shielding ink layer may be provided on the paper layer 1 instead of being provided on the paper layer 1, and further, the light-shielding ink layer may be laminated on the upper surface of the base film.

  Moreover, as a base film used for the base film layer 3 which comprises the cover material 10 of this invention, a stretched polyethylene terephthalate film, a stretched polystyrene film, a stretched polyethylene film, a stretched polypropylene film, a stretched nylon film etc. are mentioned, It can be appropriately selected according to the like. Particularly preferred is a stretched polyethylene terephthalate film or a stretched polystyrene film. By using either of these, a dead hold property can be obtained. Moreover, since the dead hold property is better as the thickness is thinner, 5 to 15 μm is desirable, and more preferably 5 to 12 μm.

  The paper layer 1 and the base film layer 3 are bonded with an adhesive layer 2 made of a linear thermoplastic resin layer. The thickness of the plurality of linear thermoplastic resin layers is preferably 3 to 30 μm, and the thermoplastic resin is composed of low density polyethylene, linear low density polyethylene, polypropylene, ethylene-vinyl acetate copolymer resin, ethylene and acid. A thermoplastic resin layer mainly composed of at least one of a copolymer resin and a synthetic rubber is preferable. By limiting the thickness of the adhesive layer as described above, the gap between the paper layer and the base film layer in the non-contact portion necessary for bending the paper layer can be sufficiently obtained.

Further, if the thermoplastic resin layer is used as a hot melt agent, an extruded resin layer, or a non-solvent laminating adhesive, it is easy to process and sufficient adhesion can be obtained. Further, in order to obtain the resin thickness, it is necessary to form an adhesive layer with these thermoplastic resin layers. Therefore, the thermoplastic resin layer is preferably laminated by any one of melt extrusion processing, hot melt spray processing, hot melt gravure coating, hot melt extrusion processing, and non-solvent lamination gravure processing. The line width X of the thermoplastic resin layer is preferably 1 to 20 mm, and the line-to-line distance Y is preferably 1 to 10 mm. By doing so, the adhesive strength between the paper layer and the base film layer is sufficient. And dead hold property can be kept moderate. Further, by limiting the distance between the lines, it is possible to secure a width necessary for the paper single layer to be bent. When the line width is excessively large, the unbonded portion is insufficient, so that the dead hold property is insufficient, and when the line width is too thin, the adhesive strength between the paper layer and the base film layer is insufficient.

The sealant layer 4 may be a single layer or multiple layers, but the innermost surface (lowermost layer) of the sealant layer 4 is the same as the adhesive resin layer 2, such as a low density polyethylene layer, a linear low density polyethylene layer, and ethylene-vinyl acetate. It is preferably an easy peel sealant resin layer mainly composed of an acid copolymer resin layer such as a polymer resin layer, an ethylene-methacrylic acid copolymer resin layer, or an ethylene-acrylic acid copolymer resin layer. In any case, the material of these sealant layers 4 is selected according to the material on at least the joint surface side of the opening peripheral edge of the adherend container. When the sealant is sealed to the container and the lid member is peeled off from the container body The intermediate peak of 45 ° peeling evaluation according to JIS S0022 is preferably 1N or more. Thereby, heat-sealing can be performed while ensuring easy peelability.

In addition, as shown in FIG. 3, a notch 7 that penetrates from the paper layer to the resin layer may be provided in the opening tab, or a broken line-like notch 8 that penetrates only the paper layer may be disposed at the boundary of the tab. Thereby, the latching | locking part which can be latched to the to-be-adhered container peripheral part of a cover material can be formed, and the further improvement measure of the dead hold property at the time of resealing can also be provided.

  Specific examples of the present invention will be described below.

<Example 1>
A heat-sealing lid material 10 having the configuration shown in FIG. 1 is produced, and a paper base material having a total paper basis weight of 80 g / m ² is used as the base material of the paper layer of the lid material. A paper layer 1 was formed by printing a pattern ink layer such as characters, patterns, and glossy varnish using a printing machine.

Next, as the base film layer 3, a 12 μm thick biaxially stretched polyethylene terephthalate film is coated with a light-shielding ink containing a mixed pigment of carbon black and titanium oxide using a multicolor gravure printing machine on a plate depth of 35 μm. The solid printing plate was overprinted with 2 units, and a light-shielding ink layer having a coating amount of 6 g / m ² (solid content) was provided.

  Next, after applying an anchor coating agent (A3210, Takeda Chemical) on the surface of the light-shielding ink layer of the base film layer 3, using a T-die type extrusion laminating machine, holes are equally spaced at intervals of 1.5 mm ( A metal plate with a diameter of 0.8 mm is fixed in advance to the lip portion of the T die, and a low density polyethylene resin (Mirason 67, Mitsui Chemicals) is extruded at a T die outlet temperature of 260 ° C. and a screw rotation speed of 50 rpm, and a processing speed of 120 m / min. , Extruded to a resin thickness of 30 μm, resin width of 3 mm, pitch width of 3 mm, and sandwiched by a cooling roll while sandwiched by a paper layer 1 that has been subjected to corona discharge treatment on the back side in advance, and further anchored to the inner surface of the base film layer 3 After coating the coating agent (A3210, Takeda Chemical), an ethylene-methacrylic acid copolymer resin layer (thickness 15) from a normal T die. m) / ethylene - methacrylic acid copolymer base resin easy peel sealant layer (laminated by co-extrusion resin finishing the two layers of thickness 15 [mu] m) and a sealant layer 4, to prepare the cover material raw of Example 1.

  A sheet of the lid material produced as described above is punched into a circular shape with a diameter of 180 mm with a tab for opening so as to be peeled off perpendicularly to the direction of the paper layer (length of the aligned fibers) of the paper layer 1. A leaf-shaped lid was prepared and used as Example 1.

<Example 2>
The same paper layer 1 and base film layer 3 as in Example 1 are used, but the adhesive layer 2 is applied to the inner surface of the paper layer 1 by hot-melt agent R-664 (Toyo Adresse) at 120 ° C. by a curtain spray method at a thickness of 30 μm, 5 mm Extruded at intervals of 5 mm in resin thickness, similarly, the base film 3 was laminated, and the inner surface of the base film 3 was further coated with a hot melt agent) H-603 (Toyo Adress) to a thickness of 20 μm at 160 ° C. by a gravure coating method. A material using a cover material was designated as Example 2.

<Example 3>
The same as in Example 1 except for the pattern of the plurality of linear adhesive layers 2, and the lid layer raw material in which the pattern of the adhesive layer 2 was laminated with a linear resin width of 3 mm and a distance between the lines of 0.5 mm A product using anti-reflective property was designated as Example 3.

  Hereinafter, comparative examples of the present invention will be described.

<Comparative Example 1>
Except for Example 1 and the innermost sealant layer 4, the innermost sealant layer 4 is formed by using a lid material raw material in which an ethylene-methacrylic acid copolymer resin layer (thickness 30 μm) is laminated as a single layer. It was set as Comparative Example 1.

The raw materials of Examples 1 to 3 and Comparative Example 1 produced as described above were 180 mm in diameter with a knob piece (opening tab) perpendicular to the direction of the paper layer 1 (length of the aligned fibers) of the paper layer 1. After punching into a circular shape, a single-wafer-shaped lid member was produced, heat sealed at 130 ° C. × 0.5 sec × 0.3 MPa in a molded polystyrene foam container, and the dead hold property was examined as follows.
<Evaluation method>
The lid materials of Examples 1 to 3 and Comparative Example 1 produced as described above were heat-sealed at 130 ° C. × 0.5 sec × 0.3 MPa in a foamed polystyrene molding container, and the dead hold property was examined as follows. .

  In accordance with JIS S0022, the container half was peeled off from the knob piece at an angle of 45 ° and an intermediate peak in the middle of peeling was measured, and then the opening angle was confirmed visually from the side of the container. At this time, if the angle of the container flange / lid is 30 ° or more, the dead hold property is good, and this is shown as ◯, and if it is 30 ° or less, the dead hold property is bad, and this is shown as x. It was. The results are shown in Table 1.

＜比較結果＞
上記実施例１乃至３による本発明品は、いずれもデットホールド性が良好であり、容器に使用したときに、開封時の蓋材の開口保持性、およびその戻しによる再封性にも優れるものである。また、アルミニウム箔などの金属を使用していないので、食品の充填時の金属探知機による検査が可能であり、電子レンジ調理をすることも可能で、使用後の廃棄性にも優れている。一方比較例１では、デットホールド性が不良となり、容器に使用したときの、開封時の開口保持性、およびその戻しによる再封性に問題がある。

<Comparison result>
All of the products of the present invention according to Examples 1 to 3 have good dead holdability, and when used in a container, they also have excellent opening holdability of the lid material at the time of opening and resealability by returning it. It is. In addition, since a metal such as aluminum foil is not used, it can be inspected by a metal detector when filling food, can be cooked in a microwave oven, and is excellent in disposal after use. On the other hand, in Comparative Example 1, the dead holdability is poor, and there is a problem in the opening holdability at the time of opening and the resealability by returning it when used in a container.

DESCRIPTION OF SYMBOLS 1 ... Paper layer 2 ... Adhesive layer 3 ... Base film layer 4 ... Sealant layer 5 ... Gap 6 ... Opening tab 7 ... Notch 8 ... Broken line shape Cut 10 ... Lid 20 ... Container body 21 ... Opening edge

Claims (5)

A lid member for sealing the upper end opening of the container body, which is made of a laminated body not including a metal layer, and has a lid body that is substantially the same type as the outer periphery of the upper end opening of the container body and outside the outer periphery. And the laminated body is laminated in order of a paper layer, an adhesive layer, a base film layer, and a sealant layer from the outer surface, and the adhesive layer is peeled off from the opening tab. A plurality of linear thermoplastic resin layers extending in a direction orthogonal to the direction, the basis weight of the paper layer is 50 to 150 g / m ² , and the lid material sealed to the container body is peeled from the container body A lid material characterized in that an intermediate peak of 45 ° peeling evaluation according to JIS-S0022 is 1.5 N or more.   The lid material according to claim 1, wherein a line width of the plurality of linear thermoplastic resin layers is 1 to 20 mm, and a distance between the lines is 1 to 10 mm.   The lid material according to claim 1 or 2, wherein the base film layer is a biaxially stretched polyethylene terephthalate film having a thickness of 5 to 15 µm or a layer of a biaxially stretched polystyrene film.   The thickness of the plurality of linear thermoplastic resin layers is 3 to 30 μm, and the thermoplastic resin is low density polyethylene, linear low density polyethylene, polypropylene, ethylene-vinyl acetate copolymer resin, ethylene and acid The lid material according to any one of claims 1 to 3, wherein the lid material is a resin mainly composed of at least one of a copolymer resin and a synthetic rubber.   The thermoplastic resin layer is laminated by any one of melt extrusion processing, hot melt spray processing, hot melt gravure coating, hot melt extrusion processing, and non-solvent lamination gravure processing. The lid material according to any one of the above.

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