JP2681060B2 - Easy-open packaging container and manufacturing method thereof - Google Patents

Description

The present invention relates to an easily openable packaging container and a method for producing the same. More specifically, the present invention is a food product,
The present invention relates to an easily openable packaging container which is suitable for packaging of beverages and the like, particularly heat sterilization packaging, can be firmly heat-sealed, has excellent sealing property, and has excellent opening property, and a manufacturing method thereof. [Prior Art] Conventionally, for packaging foods and the like, a container is filled with contents, and then a lid member is heat-sealed for sealing. However, in the heat-sealed packaging container formed in this way, if the heat-sealing strength is increased and the sealing property is increased, the unsealing property when using the contents is poor, and the unsealing with a knife or the like is required. If you select a material with an appropriate heat seal strength to improve the openability, the temperature,
Due to heat sealing conditions such as pressure and time, and contaminants such as fillers, the sealing property changes significantly, a certain adhesive force cannot be obtained, and the sealing property decreases, so the internal pressure is high due to heat sterilization such as retort. There is a problem that it is not used for packaging. In order to solve this problem, JP-A-61-190461 discloses that a resin having an appropriate internal cohesive strength is selected as a seal layer resin, and an easy-opening property is achieved by utilizing cohesive failure of the seal layer resin. Although the method is described, there is a problem that the resin of the seal layer is limited and a peeled surface is not obtained. Further, in JP-A-61-193848, a combination of a multilayer material made of an ethylene-vinyl acetate copolymer and an ionomer and a resin material made of an ionomer is selected as a resin material, and heat sealing is performed to facilitate easy opening. However, the combination of resin materials is limited to the above because it is a tear opening, and the tear surface does not cut the opening surface and the remaining surface cleanly, and the opening surface is The problem is that it is aesthetically inferior. Further, in JP-A-54-143388, at least one of the resin materials to be heat-sealed is provided with a resin printing layer which easily breaks the film, and in JP-A-61-203372, a resin to be heat-sealed. A method for facilitating the peeling of the resin material to achieve easy opening by providing a release printing layer on at least one of the materials is described, but both require a printing step, and a printing part and Since it is necessary to match the seal portion, the process becomes complicated, which is not common. [Problems to be Solved by the Invention] As shown in FIG. 6 and FIG.
The innermost layer 2 of the multi-layer cover material is heat-sealed and packaged in the flange portion 4 of the container body with the cutouts 6 ', 7'provided, and the container is opened by delamination of the cover material at the time of opening. We proposed an easy-open container with excellent sealing and opening properties.
However, in order to manufacture this container, a step of forming a notch in the lid material is required, and since the lid material is thin, the notch formation is not easy. Further, there is a problem in manufacturing that it is difficult to align the cut portion of the lid material and the seal portion during heat sealing. The present invention utilizes delamination of a heat-sealed multilayer lid material for opening, an easily openable packaging container having excellent sealing properties and excellent opening properties can be obtained by a normal sealing method, and It is an object of the present invention to provide an easily openable packaging container which can manufacture an easily openable container at low cost without requiring a complicated process, and a manufacturing method thereof. [Means for Solving the Problems] That is, according to the present invention, in a packaging container in which a container flange portion is heat-sealed with a multilayer lid member, an innermost layer of the lid multilayer lid member and a layer in contact with the innermost layer are formed so as to be peelable. In addition, the present invention relates to an easily openable packaging container, in which concave portions formed by pressing are formed in the innermost layer of the lid material inside and outside the seal portion. Such an easily openable packaging container has, for example, a container flange portion, in which the innermost layer and a layer in contact therewith are formed in a peelable manner, and the innermost layer has a lower melting point or softening point than the material of the layer in contact with the innermost layer. It can be manufactured by heat-sealing the multi-layer lid material, which is a thermoplastic resin layer, using a seal ring having convex portions on the inner and outer peripheral portions. Hereinafter, the present invention will be described in detail with reference to the drawings. First
The drawings are cross-sectional explanatory views for explaining a preferred embodiment of the easily openable packaging container and the manufacturing method thereof according to the present invention. In FIG. 1, 2 is the innermost layer of the multi-layer cover material, and 1 is the layer in contact with it. 3 is a container body, 4 is a flange portion of the container, and the contents are filled and then covered with a multi-layer lid material. The lid material is tightly heat-sealed at the container body and at the flange portion 4. 5 shows the position of the heat seal part. Concave portions 6 and 7 are formed at the inner end and the outer end of the innermost layer of the lid material of the heat seal portion. Reference numeral 9 denotes a seal ring, which is used to press the multi-layer lid member against the container flange portion and heat seal it to form a concave portion. The concave portion 7 at the outer end of the heat-sealing portion is for starting peeling between the innermost layer of the multilayer lid member and the layer in contact with it when opening, and by lifting the knob portion 8, the concave portion 7 to the concave portion 6 are removed. The peeling is performed between the layer 1 and the innermost layer 2 of the multi-layer lid material. The concave portion 6 at the inner end of the heat seal portion is for stopping peeling of the multilayer lid material. After the multilayer lid material is separated up to this point, peeling of the lid material is stopped, and the multilayer lid material inside the heat seal portion is opened. Is done. The shape of the concave portion is preferably such that the tip of the concave portion reaches the flange surface of the container body from the viewpoint of unsealing property. Also,
The recessed portion may be provided in an annular shape, such as a circle, a triangle, or a quadrangle, around the entire inner circumference of the flange, or a part thereof may be left. If you want to remove the lid with a part of it, do not provide the concave part only there. As shown in FIG. 1, the seal ring for forming the concave portion is one having convex portions 10 and 11 protruding on the heat-sealing surface on the inner and outer peripheral portions of the ring. A non-pressing portion 12 having a width t is preferably used between the inner convex portion and the heat seal portion. When the multi-layer lid material is heat-sealed to the container flange portion using such a seal ring, a non-heat-sealed portion having a width t is formed between the inner convex portion and the inner end of the heat-sealed portion. By doing this, when the multi-layer lid material is peeled from the inside,
Since stress is concentrated on the points, and peeling from the concave portion 6 is unlikely to occur, peel strength from the inside is larger than peel strength from the outside, pressure resistance is high, and sealing performance is improved.
The width of t is usually 1 to 10 mm, preferably 2 to 10 mm. The width b of the seal ring is not particularly limited and is usually 1 to 10 mm.
The height h of the convex portion provided on the peripheral edge of the ring is not particularly limited and may be determined in consideration of the material of the lid material and the like, and is usually 10 to 500 μm, preferably 2 to 30 μm. 2 and 3 are partial cross-sectional explanatory views showing another embodiment of the easily openable container and the manufacturing method thereof according to the present invention. In FIG. 2, the container is provided with ribs. In FIG. 3, the container is provided with a curl, and the seal ring is not provided with a non-pressing portion. FIG. 4 is a cross-sectional view showing a state of the unsealed portion of the container shown in FIG. The easily openable container of the present invention can be easily opened even if the container is provided with such curls and ribs. The shape of the multilayer container body in the easy-open packaging container of the present invention is not particularly limited, but is usually a circle, a square, etc., and the lid member is heat-sealed in an annular shape along the flange portion of this shape. . The multilayer lid used in the present invention comprises a base material layer and an innermost layer sealed to the container body, and the innermost layer is made of a thermoplastic resin having a lower melting point or softening point than the material of the base material layer in contact with the base material layer. Has become. As the base material layer, polypropylene, a polyolefin resin containing 20 to 80% by weight of an inorganic filler, a polycarbonate resin, a polyester resin, an ethylene-vinyl alcohol copolymer, a polyvinylidene chloride resin polyamide resin such as a single-layer film of plastic, Alternatively, a multi-layer film of these plastics, paper, aluminum foil, iron, or a composite material thereof may be used. Examples of the thermoplastic resin of the innermost layer include polyethylene such as low density polyethylene and high density polyethylene; polypropylene; ethylene-α-olefin copolymer having a density of 0.86 to 0.95; ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer. Polymer, ethylene-ethyl acrylate copolymer, ethylene-maleic anhydride copolymer,
An ethylene-unsaturated carboxylic acid copolymer such as a metal salt (ionomer resin) such as a zinc, sodium or calcium salt of an ethylene-acrylic acid copolymer; Can be mentioned. The multilayer lid material has an interlayer adhesive strength smaller than the heat seal strength between the container body and the multilayer lid material, and when the lid material is opened, there is no particular limitation as long as it is formed so as to be peelable between the layers of the multilayer lid material, The delamination strength of this multi-layer lid is usually 200-1500g
/ 15mm (pulling speed 300mm / min, same below), preferably 30
It is about 0 to 1200g / 15mm. The thickness of the innermost layer of the multilayer lid member is usually 10 to 100 μm, preferably 15 to 70 μm. The multi-layer lid material may be in the form of a film, but it may be in the form of a drop lid as shown in FIG. The shape of the recess of the drop lid is not particularly limited as long as it can fit into the opening of the container body and expel air, and may be curved, the bottom surface is the water surface, or the like. Further, as a method for forming the dropping lid, thermoforming such as vacuum forming and pressure forming, press forming, and the like are used. Even if such a drop lid is used, it has excellent openability.Therefore, even if the contents overflowing when the drop lid is set adhere to the heat seal part, the temperature and pressure at the time of heat sealing should be increased to prevent heat. It is possible to increase the sealing strength and obtain high sealing performance. As the material of the container body used in the present invention,
There is no particular limitation, and polyolefin resins such as polyethylene and polypropylene, polystyrene resins, polyamide resins, polyester resins, polycarbonate resins, ethylene-vinyl alcohol copolymers, polyvinylidene chloride resins, polyacrylonitrile, or mixtures thereof. Alternatively, a thermoplastic elastomer, various additives, or a resin obtained by mixing 5 to 70% by weight of an inorganic filler with these, metal, paper or the like can be used. For the purpose of improving the gas barrier property and reducing the deformation when used as a container, the container body of the present invention may use a multilayer material of two or more layers in which layers made of another material are laminated. Examples of layers made of other materials include resin layers such as ethylene-vinyl alcohol copolymer, polyvinylidene chloride, nylon, and polyethylene terephthalate, and aluminum vapor deposition layers, and aluminum foils having excellent gas barrier properties. Further, it may be a composite material with paper or the like. The layer made of these other materials may be only one layer, may be a multilayer body made of two or more layers, and may be a resin layer containing 10 to 80% by weight of an inorganic filler. The resin container body is formed by vacuum molding, pressure molding or the like of a plastic sheet, a coextrusion multilayer sheet or a laminated sheet obtained by using the above-mentioned resin, or by injection molding, injection blow molding, blow molding, or the like. It can be obtained by molding. Further, it can be obtained by thermoforming the multilayer film inside a container such as paper. As the lamination, for example, a method such as extrusion lamination, hot melt lamination, dry lamination, or wet lamination can be used. Further, a composite container of paper, metal and resin can be obtained by molding into a container body by bonding, winding or the like. [Operation] When the product is sealed in the easily openable packaging container of the present invention and the multi-layered lid material is heat-sealed, it can be easily opened by the following operation. For example, in FIG. 4, the knob portion 8 is lifted up. Then, from the concave portion 7 to the innermost layer 2 of the multilayer lid material.
Peeling is started between the layer 1 and the layer 1 in contact therewith, and subsequently the peeling progresses between the innermost layer 1 of the heat seal portion and the layer 2 in contact therewith, and the innermost layer peels up to the recess 6, and then The entire lid material is opened from the position of 6. Therefore, even if the multi-layer lid member and the container body are heat-sealed with good sealing property, they can be easily opened. In addition, the sealing conditions such as the sealing width can be freely set, and even if there is a deviation of the sealing, the easy opening property is not impaired. As a result, the package can be easily opened and can be peeled even if the peel strength of the heat seal is increased, so that the package can be easily opened, which is particularly resistant to boiling and retort treatment. Also, by replacing only the heat seal ring, it can be applied to containers of any shape and material, so its use,
The range of application is very large. EXAMPLES Next, the present invention will be described in more detail with reference to Examples.
The present invention is not limited in any way by these examples. Example 1 A high-density polyethylene sheet having a thickness of 800 μ was vacuum- and pressure-formed to form a flanged container having ribs of 80 mmφ × 40 mm (height). As a lid material for this container, a multilayer lid made of ethylene-vinyl acetate copolymer / polypropylene (inner layer / outer layer, 25 μ / 200 μ) was thermoformed, and a drop lid as shown in FIG. And b = as shown in FIG.
5mm, h = 50μ seal ring, temperature 170 ℃, pressure
Heat sealing was performed at 2 kg / cm ² for 2 seconds. The thickness of the innermost layer of the lid material of the concave portion obtained by heat sealing was substantially zero. The thus-obtained sealed container could be easily opened by peeling between the layers of the multilayer lid material when the lid material was opened. Example 2 An ionomer / polyethylene terephthalate (inner layer / outer layer, 20 μm) was used as a lid for the container body obtained in Example 1.
/ 100μ) and cover with a film-like lid material consisting of a multilayer sheet, and at the flange part b = 6 mm as shown in Fig. 2,
Using a seal ring of t = 2mm, h = 40μ, temperature 170 ℃,
Heat sealing was performed at a pressure of 2 kg / cm ₂ for 2 seconds. The thickness of the innermost layer of the lid material of the concave portion obtained by heat sealing was substantially zero. When internal pressure was applied to this container with a pump, the lid material bulged in a convex shape from the point A as a base point, but peeling of the heat-sealed surface did not occur. The thus-obtained sealed container could be easily opened by peeling between the layers of the multilayer lid material when the lid material was opened. [Advantages of the Invention] The present invention has excellent features such as high sealing strength, excellent sealing property, easy opening, and good appearance of peeling surface, and boil or retort treatment. It is possible to obtain an easy-open packaging container that is easy to manufacture because it can be manufactured by simply sealing it with a heat seal ring, and no special equipment is required. The seal width can be arbitrarily set without being limited to the curled flange or the like, and thus the practical value of the present invention is extremely large.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross-sectional explanatory view showing a state where heat sealing is performed in an embodiment of the easily openable packaging container of the present invention, FIG.
FIG. 3 and FIG. 3 are partial cross-sectional views of another embodiment of the easily openable package of the present invention, and FIG. 4 is a partial cross-sectional view showing the state of the container of FIG. 3 after opening. FIG. 5 is a cross-sectional view of the lid member and the container when the multilayer lid member is a drop lid in the present invention. Sixth
FIG. 7 is a partial cross-sectional view of the packaging container previously filed by the present inventors, and FIG. 7 is a partial cross-sectional view showing the opened state thereof. In the figure, reference numeral 1 is a layer in contact with the innermost layer of the multilayer lid member, 2 is the innermost layer, 3 is a container body, 4 is a container flange portion, and 6 and 7 are concave portions.

Claims (1)

(57) [Claims] In a packaging container formed by heat-sealing a multi-layer lid material on a container flange portion, the innermost layer of the multi-layer lid material and a layer in contact with the multi-layer lid material are formed so as to be peelable, and pressed against the innermost layer of the lid material inside and outside the seal portion. An easily openable packaging container having a concave portion formed by. 2. The easy-open packaging container according to claim 1, wherein a concave portion formed by pressing is formed in the innermost layer of the lid material inside the seal portion, with a non-heat seal portion being separated. 3. In the container flange portion, the innermost layer and a layer in contact with it are formed in a peelable manner, and the innermost layer is a thermoplastic resin layer having a lower melting point or softening point than the material of the layer in contact with it, a multilayer lid material, A method for producing an easy-open packaging container, characterized by heat-sealing using a seal ring having convex portions on inner and outer peripheral portions. 4. The method for producing an easily openable packaging container according to claim 3, wherein heat sealing is performed using a seal ring having a non-pressing portion on the inner peripheral portion of the heat sealing surface.