JP2006151475A - Easy-to-seal type container and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an easy-to-seal type container having an easy-to-seal structure and its manufacturing method in which a lid member heat sealed to a container main body can be easily peeled off, its sealing can be opened and a smooth peeling and sealing can be carried out without damaging a sealing characteristic at the container. <P>SOLUTION: A sealing start part 41 provided with a flap part 41a protruded outside a container is formed at a seal part 4 between a lid member 3 and a flange 23, two sides 41a1, 41a2 forming the flap part 41a are made substantially straight shape and at the same time a sum (W1+W2) of a seal width extending along a direction perpendicular to a sealing direction Z of the lid member 3 at a portion except the extremity end 411 of the sealing start part 41 is adjusted within a range of 5 to 10 mm. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an easy-open container having an easy-open structure in which a lid heat-sealed to a container body can be easily and smoothly opened and a method for manufacturing the same.

A container that is molded into a predetermined container shape such as a cup shape or a tray shape, has a flange formed along the periphery of the container opening, and heat seals the lid to the flange so as to hermetically contain the contents. Widely used as sealed containers for chemicals and chemicals.
In this type of sealed container, when the container is opened and the contents are taken out, there is a demand for easy opening so that the lid can be easily peeled open. For example, Patent Document 1 discloses a plastic container body. By providing a ridge that joins the lid over the entire circumference of the flange formed at the periphery of the opening of the rim, and forming a part of this ridge in the shape of a lip that protrudes outward, An easy-open structure that triggers lid peeling is shown.

JP 2003-54634 A

  However, in the case where the seal shape at the opening start position that causes the lid to peel off is formed in a mouth shape (see FIG. 6), the tip of the mouth portion is easy to peel off, but the lid body When peeling has shifted to the part that spans the two sides that form the mouthpiece-like part, the resistance when the lid is peeled off suddenly increases, making it difficult to peel off the lid. There was a problem that the contents of the fingers were spilled due to excessive force applied to the finger or the like to peel off the contents.

In order to improve such a problem, the mouth portion is formed in a tapered shape (see FIG. 5), and the tip portion of the mouth portion and a portion extending over the two sides forming the mouth portion are formed. There is also a type in which a change in resistance when the lid is peeled off is reduced.
However, this has a problem that the resistance changes greatly at the inflection point of the curve.

  In order to reduce the change in resistance when the lid is peeled off, it may be possible to reduce the seal width entirely or partially, but if the seal width is reduced, sufficient seal strength cannot be obtained. The problem arises that the sealing performance is impaired.

  As described above, an easy-open structure is desired in which the resistance does not change greatly in the process of peeling off the lid while exhibiting a certain sealing strength. However, there is still room for improvement in order to make the cover body smooth and easy to peel open.

  The present invention has been proposed in order to solve the problems of the conventional techniques as described above. The lid heat-sealed on the container body can be easily peeled and opened, and the container can be sealed. It is an object of the present invention to provide an easy-open container having an easy-open structure that enables smooth peeling and opening without damaging and a method for producing the same.

The easy-open container according to the present invention is an easy-open container formed by heat-sealing a lid having a heat seal layer on the inner surface with the heat seal layer facing the opening peripheral edge of the container body, The lid in the portion excluding the front end portion of the opening start portion is formed with a sealing portion between the lid body and the peripheral edge portion of the opening, with an opening start portion having a mouth portion protruding outward from the container. The total seal width along the direction orthogonal to the body opening direction is set to 5 to 10 mm.
With such a configuration, the lid body heat-sealed to the container body can be easily and smoothly peeled and opened while having sufficient sealing strength.

  In the easily openable container according to the present invention, in order to adjust the seal width in the above range, two sides forming the mouth opening may be tapered, and the seal portion of the opening start portion Some may be hollowed out. Moreover, the angle can also be set suitably in the range from which the angle which the edge of the container outer side of two sides which forms the said mouth part makes becomes 90-120 degrees.

  Further, in the easy-open container according to the present invention, in order to ensure the sealing area at the tip of the opening start portion and not to impair the sealing performance, the tip of the opening start portion The length along the opening direction of the lid is preferably 1.5 to 3.5 mm.

Further, in the easily openable container according to the present invention, the seal width along the direction perpendicular to the opening direction of the lid body at the opening start portion so that the lid body can be peeled and opened more smoothly. Is preferably smaller on the distal end side than on the base side of the opening start portion.
In this case, along the direction orthogonal to the opening direction of the lid at the tip of the opening start portion with respect to the total seal width along the direction orthogonal to the opening direction of the lid on the base side of the opening start portion. The ratio of the maximum seal width is preferably 0.3 to 0.9.

Moreover, in the easy-open container according to the present invention, one side and the other side with respect to a center line that equally divides the angle formed by the outer edges of the two sides forming the mouth portion. The sides can be symmetric.
Thereby, the opening direction can be controlled so that the lid body is peeled and opened along the center line, and the smooth peeling and opening of the lid body can be made more reliable.

Further, in the method for producing an easily openable container according to the present invention, the lid having a heat seal layer on the inner surface is placed with the heat seal layer facing the opening peripheral edge of the container body, and the lid and the A method of manufacturing an easily openable container, wherein the lid body is heat-sealed to the container main body by heating and pressurizing the peripheral edge of the opening to form the seal part. An opening start portion having a mouth portion that is convex toward the front is formed, and the total seal width along the direction orthogonal to the opening direction of the lid body in the portion excluding the tip portion of the opening start portion is 5 to 10 mm. It is a method of forming so that.
By adopting such a method, while having sufficient sealing strength, easy opening with an easy opening structure that can easily and smoothly peel and open the lid heat-sealed to the container body. Containers can be manufactured.

  According to the present invention, an easy-opening capable of smoothly peeling and opening the lid without significantly changing the feeling of resistance when peeling the lid while ensuring a sufficient sealing strength between the lid and the container body. Sex containers can be obtained.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. Fig.1 (a) is a perspective view which shows schematically one Embodiment of the easily openable container which concerns on this invention, FIG.1 (b) is AA sectional drawing of Fig.1 (a).

In the example shown in FIG. 1, the container 1 includes a container main body 2 and a lid 3 that is heat-sealed to the peripheral edge of the opening of the container main body 2 after the contents are stored in the container main body 2. The container body 2 includes a trunk portion 21, a bottom portion 22 that is continuous with the lower end of the trunk portion 21, and a heat seal flange 23 that is continuous with the upper end of the trunk portion 21.
The flange 23 is formed so as to protrude horizontally along the periphery of the opening of the container body 2, and forms the opening periphery of the container body 2. The lid 23 having the heat seal layer 31 on the inner surface is heat-sealed on the flange 23, whereby the opening of the container body 2 is sealed.

  The heat seal is placed on the cradle with the heat seal layer 31 of the lid 3 in contact with the upper surface of the flange 23, and a heat seal bar, a high frequency induction heating heat seal head, a dielectric heating heat seal is mounted. This is performed by heating and pressurizing the seal portion with a head, an ultrasonic heat seal head or the like.

When the lid 3 is heat-sealed to the flange 23, the heat-sealing conditions are appropriately set so that the lid 3 is securely bonded to the flange 23. Usually, the heat-sealing temperature is 160 to 220 ° C. Do. The pressing force of the seal head is usually about 1.0 to 2.5 MPa (10 to 25 kg / cm ² ), and the heat sealing time is usually about 0.5 to 2.0 seconds. At this time, the sealing strength between the heat seal layer 31 and the flange 23 is preferably set as appropriate in the range of 0.5 to 3.0 N / 15 mm in consideration of the peel-opening property of the lid 3.

The seal portion 4 that joins the lid 3 and the flange 23 is usually formed over the entire circumference of the flange 23. In this embodiment, when the lid 3 is heat-sealed to the flange 23, as shown in FIG. In addition, an opening start portion 41 having a mouth portion 41a that protrudes outward from the container is formed on a part of the seal portion 4, and the opening start portion 41 starts opening when the lid 3 is peeled open. It is supposed to be a position.
Note that FIG. 2 is an enlarged view of a main part of a plan view of a portion surrounded by a broken line in FIG. 1A. In the drawing, the lid 3 is indicated by a two-dot chain line, and the flange 23 and the seal part 4 are indicated by a solid line. ing.

  In the example shown in FIG. 2, the mouth opening portion 41 a provided in the opening start portion 41 has a substantially linear shape in which a part of the seal portion 4 is protruded outwardly of the container and intersected so as to protrude outwardly of the container. It consists of two sides 41a1 and 41a2. The two sides 41a1 and 41a2 that form the throat portion 41a intersect so as to form a triangular tip portion 411 and are tapered toward the tip portion 411.

Further, the two sides 41a1 and 41a2 forming the mouth opening portion 41a are continuous with the other seal portion 42 except the opening start portion 41 at the base portion 412 of the opening start portion 41 with the same seal width W0.
The seal width W0 here refers to the width in the direction orthogonal to the extending direction of the seal portion 4, and the seal width W0 of the other seal portions 42 excluding the opening start portion 41 is usually 2.5. It is formed to about ~ 4.0 mm. Further, in the figure, the boundary between the opening start portion 41 and the other seal portion 42 is indicated by a broken line, and the other seal portion 42 is indicated by a hatched line. In the seal portion 4 extending along the direction, the width of the seal portion 4 changes in the direction orthogonal to the extending direction, or in the extending direction of the seal portion 4 in the extending direction of the opening peripheral portion of the container body 2. In contrast to the case where the seal portion 4 is extended along the peripheral edge of the opening of the container body 2 based on the normal design concept without forming the opening start portion 41, such as a portion where the displacement occurs, the opening start portion It is assumed that some change begins to occur as 41 is formed, and the boundary line is drawn in a direction orthogonal to the extending direction of the other seal portions 42.

Such an opening start part 41 is formed in order to reduce the force required to peel off the lid 3 in the initial stage of opening and facilitate the peeling and opening of the lid 3, The opening start portion 41 of the opening start portion 41 is reduced so that the change in resistance when the lid 3 is peeled off is reduced between the tip portion 411 of the opening start portion 41 and the portion spanning the two sides 41a1 and 41a2 forming the mouth opening portion 41a. The sum of the seal widths along the direction orthogonal to the opening direction of the lid 3 (the direction indicated by the arrow Z in FIG. 2) in the portion excluding the tip 411 (in the example shown in FIG. The sum of the seal width W1 on one side 41a1 of the two sides 41a1 and 41a2 to be formed and the seal width W2 on the other side 41a2 is 5 to 10 mm, preferably 6 to 10 mm.
It should be noted that, on the base 412 side of the opening start portion 41, the seal width along the direction orthogonal to the opening direction of the lid 3 is the portion closest to the boundary with the other seal portion 42 without including the other seal portion 42. The measured value (W1b + W2b) may be within the above range, and the sum of the seal widths along the direction orthogonal to the opening direction of the lid 3 at all the sites from the measurement site to the tip 411 ( W1 + W2) should be within the above range. In addition, as long as such a relationship is satisfied, the two sides 41a1 and 41a2 forming the mouth portion 41a are not limited to a substantially linear shape as shown in FIG. It may be combined, or may be curved like a comparative example 1 or 4 described later.

When the above range is exceeded, when the peeling of the lid body 3 shifts to a portion spanning the two sides 41a1 and 41a2 that form the mouth portion 41a, a change in resistance when the lid body 3 is peeled off becomes large. It makes peeling and unsealing of the lid 3 difficult.
On the contrary, if it is less than the above range, sufficient sealing strength cannot be obtained, and the lid 3 is peeled off due to a drop impact or the like, and the sealing performance is impaired.

  Moreover, in order to ensure the sealing area in the front-end | tip part 411 of the opening start part 41, and not to impair sealing performance, the length (front-end | tip width) W along the opening direction of the cover body 3 of the front-end | tip part 411. Is preferably 1.5 to 3.5 mm, more preferably 2.0 to 3.0 mm.

In the example shown in FIG. 2, the two sides 41 a 1 and 41 a 2 that form the mouth portion 41 a are formed in a substantially linear shape and are tapered toward the tip end portion 411, thereby being orthogonal to the opening direction of the lid 3. The total seal width (W1 + W2) along the direction is adjusted. To facilitate the adjustment of the seal width, as shown in FIG. 413 can also be formed.
3 is an enlarged view of a main part similar to FIG. 2, and the lid 3 is indicated by a two-dot chain line and the flange 23 and the seal part 4 are indicated by a solid line as in FIG. 2.

  Moreover, the sum (W1 + W2) of the seal width along the direction orthogonal to the opening direction of the lid 3 can also be adjusted by appropriately setting the angle formed by the two sides 41a1 and 41a2 forming the throat portion 41a. In this case, although it depends on the shape of the flange 23 and the width (length extending in the horizontal direction), the angle θ formed by the outer edge of the container on each side is set to 90 to 120 °. Is preferred.

  Further, the total seal width (W1 + W2) along the direction orthogonal to the opening direction of the lid 3 is the opening start portion 41 so that the lid 3 can be opened and peeled more smoothly at the opening start portion 41. It is preferable to make it smaller at the tip end portion 411 side than at the base portion 412 side.

  Thereby, the force required to peel off the lid 3 at the opening start portion 41 is small on the distal end portion 411 side of the opening start portion 41 and gradually increases toward the base portion 412 of the opening start portion 41, In the vicinity of the boundary between the opening start portion 41 and the other seal portion 42, a rapid increase in the peeling force is suppressed, and the resistance when the lid body 3 is peeled is continuously observed in the process of peeling and opening the lid body 3. Can be changed.

In this case, in the opening direction of the lid 3 at the tip 411 of the opening start portion 41 with respect to the total seal width (W1b + W2b) along the direction orthogonal to the opening direction of the lid 3 on the base 412 side of the opening start portion 41. The ratio (Wa / (W1b + W2b)) of the maximum value Wa of the seal width along the orthogonal direction is preferably 0.3 to 0.9, more preferably 0.5 to 0.7.
Here, the total seal width (W1b + W2b) along the direction orthogonal to the opening direction of the lid 3 on the base 412 side of the opening start portion 41 is the most different without including the other seal portions 42 as described above. It is assumed that the seal width is measured at a portion near the boundary with the seal portion 42.

  Further, in order to avoid a change in the peeling force in the vicinity of the boundary between the opening start portion 41 and the other seal portion 42, along the direction orthogonal to the opening direction of the lid 3 on the base 412 side of the opening start portion 41. The unsealing start portion 41 and the other so that the sum of the seal widths (W1b + W2b) and the sum of the seal widths (W1c + W2c) along the direction orthogonal to the unsealing direction of the lid 3 in the other seal portions 42 do not differ greatly. It is preferable that the sealing portion 42 is continuous at the boundary between the two.

Thus, in this embodiment, the opening width | variety start part 41 provided with the opening part 41a was formed in a part of seal | sticker part 4, and the seal | sticker width along the direction orthogonal to the opening direction of the cover body 3 in the opening start part 41 By adjusting the sum total (W1 + W2) of the lid 3, the lid 3 can be smoothly peeled and opened while achieving both easy opening and sealing, but the opening 41a provided in the opening start portion 41 is shown in FIG. As shown in the example shown in FIG. 1, one side 41a1 and the other side 41a2 are formed with respect to a center line C that equally divides the angle formed by the outer edges of the two sides 41a1 and 41a2 forming the mouth part 41a. And the seal width W1 on one side along the direction perpendicular to the center line C is preferably equal to the seal width W2 on the other side.
Thereby, the opening direction can be controlled so that the lid 3 is peeled and opened along the center line C, and the smooth peeling and opening of the lid 3 can be made more reliable.

In the present embodiment, when the lid 3 is heat-sealed to the flange 23, the sealing portion 4 as described above is formed with a sealing surface having a shape corresponding to the sealing portion 4 to be formed. The sheet may be sealed using the seal head under the heat sealing conditions as described above, but a protrusion for forming the seal portion 4 may be formed on the flange 23 in advance.
That is, when the lid 3 is heat-sealed to the flange 23, for example, the protrusion formed in the same planar shape as the seal portion 4 shown in FIG. 2 and the heat seal layer 31 of the lid 3 are joined, The sealing part 4 as described above may be formed. In this case, the seal head does not need to be specially processed, and a seal head having a flat seal surface or a seal surface having a curved surface with a curvature radius of about 5 to 30 mm can be used.

  In this embodiment, the material for forming the container body 2 includes polyolefin resins such as polyethylene and polypropylene, polyamide resins such as polyamide 6, polyamide 66, and polyamide 46, or polyethylene terephthalate (PET) and polybutylene. Polyester resins such as terephthalate, polycarbonate, polyarylate, cyclic olefin copolymers and the like can be used.

  A known plastic compounding agent, for example, an antioxidant, a heat stabilizer, an ultraviolet absorber, an antistatic agent, a filler, a colorant, and the like can be blended with the thermoplastic resin. For the purpose of making the container body 2 opaque, fillers such as calcium carbonate, calcium silicate, alumina, silica, various clays, gypsum, talc and magnesia, titanium white, yellow iron oxide, bengara, ultramarine blue, chromium oxide Inorganic pigments and organic pigments such as can be blended.

  The container body 2 can also be provided with various functions by adopting a multilayer structure in which other layers such as a gas barrier layer and an oxygen-absorbing resin layer are appropriately laminated on these thermoplastic resin layers. . The other layers can be used as an inner layer or an outer layer in a two-layer configuration, or can be used as an intermediate layer in a three-layer configuration.

  The gas barrier layer is formed of any known material such as ethylene-vinyl alcohol copolymer (EVOH), nylon resin (Ny), gas barrier polyester resin (BPR), cyclic olefin copolymer, and the like. However, a layer made of a metal foil such as an aluminum foil, a tin foil, a steel foil, or a tin foil may be used.

  As the oxygen-absorbing resin layer, a layer containing a metal-based oxidation catalyst and an oxidizing organic component is used. The oxidizing organic component is a resin that is oxidized by oxygen in the air by the catalytic action of a transition metal catalyst, and includes (i) a carbon side chain (a) and a carboxylic acid group in the main chain or side chain. A resin containing at least one functional group (b) selected from the group consisting of a carboxylic acid anhydride group, a carboxylic acid ester group, a carboxylic acid amide group and a carbonyl group, (ii) a polyamide resin, and (iii) an ethylene-based resin An unsaturated group-containing polymer is used.

  As the metal-based oxidation catalyst, Group VIII metal components of the periodic table such as iron, cobalt and nickel are preferable, but other Group I metals such as copper and silver: Group IV metals such as tin, titanium and zirconium , Va group V, chromium and other group VI, and manganese and other group VII metal components. Among these metal components, the cobalt component is particularly suitable because of its high oxygen absorption rate. The transition metal catalyst is generally used in the form of a low-valent inorganic acid salt, organic acid salt or complex salt of the transition metal. These catalysts are preferably used in an amount of 100 to 1000 ppm per resin.

  Furthermore, the container body 2 may have any other resin layer in addition to the layer made of the thermoplastic resin and the gas barrier layer. For example, when there is no thermal adhesiveness between the thermoplastic resin layer and the gas barrier layer, an adhesive resin layer can be interposed between the two resin layers. The adhesive resin is not particularly limited, and acid-modified olefin resins such as maleic anhydride grafted polyethylene and maleic anhydride grafted polypropylene can be used.

  In the present embodiment, the lid 3 heat-sealed to the container body 2 has a specific configuration as long as the lid 3 has flexibility and sealing properties and has a heat-sealing layer 31 on the inner surface. Is not particularly limited. For example, metal foil such as aluminum foil, tin foil, steel foil, tin foil, high oxygen barrier resin film such as ethylene-vinyl alcohol copolymer, vinylidene chloride resin, nylon resin, biaxially stretched polyethylene terephthalate film, biaxial Taking a stretched nylon film, a thermoplastic resin film such as a polycarbonate film, various papers, or a laminate of these as a base material, considering the heat sealability with the container body 2 on the inner surface of such a base material, for example, Further, the heat seal layer 31 made of a heat seal resin appropriately selected from polyolefin resin, polyester resin, or the like can be provided. The heat seal layer 31 can be adjusted to easily openable heat seal strength by blending various modifiers with the heat seal resin.

  Next, the present invention will be described in more detail with specific examples (Examples 1 to 3 and Comparative Examples 1 to 4).

[Container body]
By ordinary co-extrusion sheet molding, outer layer: polypropylene (PP, MI = 0.5) + titanium white pigment (400 μm) / adhesive layer: maleic anhydride modified polypropylene (20 μm) / barrier layer: ethylene-vinyl alcohol copolymer A multi-layer sheet of 3 types and 5 layers (lamicon sheet) comprising union (60 μm) / adhesive layer: same as above (20 μm) / inner layer: PP (400 μm) was prepared with a total thickness of 0.9 mm.
Using the multilayer sheet thus obtained, a rectangular container with a flange having a container outer dimension of 156 mm × 133 mm and a height of 29 mm (inner volume of about 340 ml) was formed by a normal vacuum / pressure forming machine.

[Lid]
A lid having a structure of outer layer: biaxially stretched polyester film (12 μm) / intermediate layer: biaxially stretched nylon film (15 μm) / inner layer: polypropylene-based composite material (50 μm) was produced by an ordinary dry lamination method.

After filling the container body with 200 g of cooked rice in an aseptic packaging and filling line, the lid body was heat sealed to a flange under heat sealing conditions of a sealing temperature of 180 ° C., a sealing pressure of 15 MPa, and a time of 1.5 seconds.
At this time, the seal shape of the opening start part in Examples 1 to 3 and Comparative Examples 1 to 4 was as follows.

[Examples 1 and 2]
As shown in FIG. 2, the seal shape at the opening start portion was a mouth shape formed by two straight and tapered sides.

[Example 3]
As shown in FIG. 3, the seal shape at the opening start portion is a lip shape having two sides that are linear and tapered, and the center in the longitudinal direction of the two sides is tapered from the base side toward the tip portion. I pulled it out. As for the hollow width on the base side, the width orthogonal to the longitudinal direction was 1 mm.

[Comparative Example 1]
As shown in FIG. 5, the seal shape at the opening start portion was a curb shape composed of two sides having the same width and a curved shape formed by combining an arc having a curvature radius of 50 mm and an arc having a curvature radius of 20 mm.

[Comparative Examples 2 and 3]
As shown in FIG. 6, the seal shape at the opening start portion is a lip shape that is straight and has two sides of the same width.

[Comparative Example 4]
As shown in FIG. 7, the seal shape at the opening start portion is a mouth shape having two curved sides formed by combining an arc having a curvature radius of 50 mm and an arc having a curvature radius of 20 mm, and the tip width W is 2 mm. Thus, it was set as the shape similar to the comparative example 1 except narrowing down the front-end | tip part.

  4 to 6 for explaining the seal shapes of Comparative Examples 1 to 4 are enlarged views of the main part similar to FIG. 2 for explaining the embodiment according to the present invention described above. Similarly to FIG. 3 is indicated by a two-dot chain line, and the flange 23 and the seal portion 4 are indicated by a solid line. Moreover, about the structure corresponding to embodiment based on this invention, the same code | symbol is attached | subjected for convenience.

(1) Tip width W [unit: mm] of the opening start portion in Examples 1 to 3 and Comparative Examples 1 to 4
(2) Seal width W0 [unit: mm] at the base of the opening start portion
(3) Angle θ [unit: °] formed by the outer edges of the two sides of the mouth shape
(4) Maximum value Wa [unit: mm] of the seal width along the direction orthogonal to the opening direction at the tip of the opening start portion.
(5) Total seal width (W1b + W2b) [unit: mm] along the direction orthogonal to the direction orthogonal to the opening direction at the base of the opening start portion
(6) Ratio of Wa to (W1b + W2b) (Wa / (W1b + W2b))
(7) Maximum value and minimum value [unit: mm] of the sum (W1 + W2) of the seal width along the direction orthogonal to the opening direction at the opening start portion
Is shown in Table 1.

  In each of Examples 1 to 3 and Comparative Examples 1 to 4, the following evaluation tests were performed on the obtained filled containers. The results are also shown in Table 1.

[Evaluation Test 1]
Using 20 arbitrarily selected filled containers, a sensory test was conducted on the opening feeling of the lid.
[Evaluation Test 2]
The temperature of 20 arbitrarily selected filling containers was adjusted to 5 ° C., and a drop test was performed by dropping 10 times in an inverted state from a height of 1.2 m, and the presence or absence of damage was examined.
The values shown in Table 1 are the number of damaged containers.

As shown in Table 1, in Examples 1 to 3, in which the seal shape at the opening start portion is a straight and tapered two-sided shape, the force required to peel off the lid at the initial stage of opening is small. Since the resistance when the lid was peeled off did not change greatly, it could be opened very smoothly and the opening feeling was good.
On the other hand, the conventional seal shapes of Comparative Examples 1, 2, and 4 have a large force required to peel off the lid at the initial stage of opening, or the resistance when the lid is peeled off increases rapidly. Therefore, it was difficult to peel and open the lid.

  Also in the drop test, Examples 1 to 3 were not damaged and there was no problem in strength, but in Comparative Examples 3 and 4 in which the seal width was narrowed in consideration of openability, damage occurred and the difference became clear. It was.

  Although the present invention has been described with reference to the preferred embodiment, it is needless to say that the present invention is not limited to the above-described embodiment, and various modifications can be made within the scope of the present invention. .

  For example, in the above-described embodiment, the rectangular container is taken as an example, but the container shape is not particularly limited, and various shapes used for this type of container can be adopted.

  In the above-described embodiment, the opening start portion 41 is formed at the corner portion of the container 1, but the position and number of the opening start portion 41 can be determined according to the shape and size of the container 1. 3 can be arbitrarily set so that the peeling and opening of 3 can be easily performed.

  Moreover, the number of the opening part 41a with which the opening start part 41 is provided is not restricted to one, but as shown in FIG. 4, the opening start part 41 may be provided with the two opening parts 41a, and shall be three or more. You can also.

  Moreover, in embodiment mentioned above, although the thing in which the flange for heat sealing was formed along the periphery of an opening part was mentioned as an example, this invention is applicable also to the container in which the flange is not formed.

  As described above, the present invention provides an easily openable container capable of smoothly peeling and opening a lid heat-sealed to a container body and a method for manufacturing the same while ensuring sufficient sealing strength. .

It is a figure which shows the outline of one Embodiment of the easily openable container which concerns on this invention. It is a principal part enlarged view which shows the outline of an example of the seal shape of the opening start part in the easily openable container which concerns on this invention. It is a principal part enlarged view which shows the outline of the other example of the seal shape of the opening start part in the easily openable container which concerns on this invention. It is a principal part enlarged view which shows the outline of the other example of the seal shape of the opening start part in the easily openable container which concerns on this invention. It is a principal part enlarged view which shows the outline of the conventional example (comparative example 1) of the seal shape of an opening start part. It is a principal part enlarged view which shows the outline of the conventional example (comparative examples 2 and 3) of the seal shape of an opening start part. It is a principal part enlarged view which shows the outline of the conventional example (comparative example 4) of the seal shape of an opening start part.

Explanation of symbols

1 Sealed container 2 Container body 23 Flange (opening edge)
DESCRIPTION OF SYMBOLS 3 Cover body 31 Heat seal layer 4 Sealing part 41 Opening start part 41a Front part 41a1 One side which forms a front part 41a2 The other side which forms a front part 411 Front part 412 Base part 42 Other sealing part W Top part cover Length along the body opening direction W1, W2 Seal width along the direction orthogonal to the opening direction of the lid Wa Maximum seal width along the direction orthogonal to the opening direction of the lid at the tip of the opening start portion Value W1b, W2b Seal width along the direction orthogonal to the opening direction of the lid at the base of the opening start portion θ Angle formed by the outer edges of the two sides forming the mouth portion

Claims (9)

A lid having a heat seal layer on the inner surface, an easy-open container formed by heat-sealing the heat seal layer against the opening periphery of the container body,
In the seal part between the lid and the opening peripheral edge part, an opening start part having a mouth part that is convex toward the outside of the container is formed,
The easily openable container characterized in that the sum of the seal widths along the direction orthogonal to the opening direction of the lid in the portion excluding the tip of the opening start portion is 5 to 10 mm.   The easily openable container according to claim 1, wherein two sides forming the mouth portion are formed in a tapered shape.   The easily openable container according to claim 1 or 2, wherein a part of the seal portion in the opening start portion is hollowed out.   The easy-open container according to claim 1, 2 or 3, wherein an angle formed by the outer edges of the two sides forming the mouth portion is 90 to 120 °.   The easily openable container according to any one of claims 1 to 4, wherein a length of the tip of the opening start portion along the opening direction of the lid is 1.5 to 3.5 mm.   The total of the seal width along the direction orthogonal to the opening direction of the lid at the opening start portion is smaller on the tip side than the base side of the opening start portion. Easy-open container as described.   The seal width along the direction orthogonal to the opening direction of the lid at the tip of the opening start portion relative to the total seal width along the direction orthogonal to the opening direction of the lid on the base side of the opening start portion The ratio of the maximum value of is an easily openable container according to claim 6, which is 0.3 to 0.9.   The one side and the other side are symmetric with respect to a center line that equally divides the angle formed by the outer edges of the two sides forming the mouth portion. Easy-open container as described in Crab. A lid having a heat seal layer on its inner surface is placed with the heat seal layer facing the opening peripheral edge of the container body, and the lid and the opening peripheral edge are heated and pressurized to form a seal portion. According to the manufacturing method of the easy-open container formed by heat-sealing the lid body to the container body,
The seal portion,
While an opening start portion having a mouth portion that is convex toward the outside of the container is formed,
A method for producing an easily openable container, characterized in that a total sum of seal widths along a direction orthogonal to the opening direction of the lid body in a portion excluding the tip of the opening start portion is 5 to 10 mm. .

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