JPH10114356A - Container for seal-packaging, and seal-packaged body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sealing method which is simple, and can be produced at a low cost, and is easily openable by a method wherein the surface of a flange part of a plastic container main body, by which a lid member is heat- sealed, a downward slope from the internal edge to the external edge, is provided at a location where the container main body is opened upward, and the downward slope is made a surface to be heat-sealed. SOLUTION: As a surface to be heat-sealed 3 where a lid member is heat- sealed on a flange part 1, on the surface of the flange part 1, a slope which descends from the internal edge 7 (closer to a container main body) to the external edge 5 (away from the container main body), is provided. Or, a protruding part of which the cross sectional surface has a triangular protuberance, is provided, and the external slope is made the surface to be heat-sealed 3. By heat-welding the lid member on these slopes, the peeling strength from the internal side of the main body lid becomes larger than that from the external side, and an unsealing from the external side becomes easier. The material of the container main body may be anything as long as it is a material which is welded on the opening flange part 1 with the container main body, and a special processing is not required.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a container for hermetically sealed packaging, and more particularly, to a plastic container body having an opening flange portion for heat-sealing a lid material, in which contents are stored. Then, when the lid material is heat-sealed to form a sealed package, the peel strength of the lid from the inside of the package is large enough to withstand, for example, an increase in internal pressure and drop impact during retort sterilization, The present invention relates to a hermetically sealed packaging container capable of maintaining a peel strength from the outside of a package at a seal strength capable of being opened by hand.

[0002]

2. Description of the Related Art The peel strength of a lid from the inside of a sealed package satisfies the seal strength regulation of retort foods (2.3 kgf / 15 mm width), and from the outside, an easily openable sealing method or a sealed container is, for example, (1) An annular cut is provided in the peelable innermost layer of the multi-layer container, and the cover material is 0.5% of the cut.
A container that can be easily peeled (opened) from the inside by peeling off from the inside by heat sealing at the outside of 10.0 mm (JP-A-63-44467). A material is attached, and the lid material is heat-sealed with the intermediate material. The intermediate material has a multilayer structure in which an easy peel is provided on the container side and a tight seal is provided on the lid material side. In addition, the tight seal position is controlled so that it is shifted to the outside of the container from the easy peel position, so that it is difficult to peel off from the inside, and easily peeled from the outside (opening).
A container that can be made (Japanese Patent Laid-Open No. 1-29446), and
(3) A convex strip is provided on the heat plate for heat sealing, and a concave strip is formed in the heat sealing portion of the container by applying heat and pressure during sealing. The convex cross-sectional shape is a smooth shape, and the height is gradually increased from the outer edge to the inner edge. A container which is difficult to peel off from the inside and can be easily peeled off (opened) from the outside due to the concave line of the heat sealing portion corresponding to this convex line (JP-A-61-244)
703) and the like are known, but all of them are methods in which performance is not exhibited unless a third substance is incorporated or delicate control is performed, which is a complicated and cost-increasing factor.

[0003]

SUMMARY OF THE INVENTION According to the present invention, a sealing method or an easy-to-open (easy-opening) method which can easily cope with the high-level and high-cost method of the prior art described in the preceding section at a simple and low cost with conventional equipment. (Openability) It is intended to provide a sealed package.

[0004]

As a result of various studies to achieve the above-mentioned object, the present inventor adhered a gum tape on a stainless steel inclined plate and measured the peeling strength of the tape with a force gauge. Then, there is a difference between the peel strength from above to below and the peel strength from below to above,
The former was found to be greater than the latter (see Example 1 below), and the present invention was completed based on such findings.

That is, the present invention relates to a plastic container main body having an opening flange for heat-sealing a lid material, wherein the surface of the flange has an inner edge at a position where the container main body is opened upward. A container for hermetically sealed packaging, characterized in that the container has a slope descending from the bottom to the outer edge, and the descending slope is a heat sealing surface; Further, the present invention relates to a hermetically sealed package characterized in that a lid material is heat-welded on the heat sealing surface.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.

The container body of the container for hermetic packaging according to the present invention is a plastic container having an opening flange portion for heat-sealing a lid material, and is characterized by a heat-sealing surface of the flange portion. That is, when the container body is placed with its opening facing upward and crosses the flange, the shape of the surface of the flange in the cross section thereof is far from the inner edge (closer to the container body) of the flange (far from the container body). A) having a hatched portion descending toward the outer edge, so that when the container body is in the same position, the flange portion has a ramp descending from its inner edge toward the outer edge, and this descending ramp is covered with a lid; It is used as a heat sealing surface for materials. This downward slope may extend over the entire width of the flange surface,
It may occupy a part of it. Of course, this descending slope is provided over the entire circumference of the flange portion, and it is preferable that the width thereof is made as constant as possible over the entire circumference of the flange portion from the viewpoint of obtaining uniform sealing strength over the entire circumference of the container opening. Needless to say.

[0008] Such a sealed packaging container of the present invention includes:
A plastic container body having an opening flange portion to be heat-sealed with a lid material, wherein the flange portion has a ridge having a shape having a triangular protrusion on a surface thereof, and the outer slope of the ridge is formed by removing an outer slope of the ridge. A hermetically sealed container characterized by having a heat sealing surface is included. That is, in the hermetically sealed container of this aspect, when the flange portion is cut at right angles to the direction of heat sealing, the shape caused by the intersection of the surface of the flange portion and the cut surface has a triangular projection. Therefore, the flange portion has a corresponding ridge on the surface thereof. Then, when the contents are stored in such a container body to form a sealed package, heat welding of the lid material is performed.
This is performed on the outer slope of the ridge.

Next, the heat sealing surface of the flange portion of the sealed packaging container of the present invention will be described in more detail.

First, the case where the flange portion has a ridge having a projection having a triangular cross section on the surface, and the outer slope of the ridge is a heat sealing surface will be described with reference to FIG. FIG.
FIG. 4 is a cross-sectional view of such a flange portion (a conceptual diagram in which the flange portion is partially enlarged). 1 is the flange, 2
Indicates a triangular vertex, and 3 indicates a convex outer slope (heat sealing surface).
, 4 represents the inner slope of the ridge, and 5 represents the outer edge of the flange.

The practical inclination angle (α) of the convex ridge outer slope (3) from the inner edge to the outer edge of the flange portion is in the range of 10 to 60 °. At a gentle angle of 10 ° or less, it is the same as that of a flat surface with no ridges on the flange surface, and at 60 ° or more, it is too steep and difficult to heat weld with the lid material. . Also, the inner slope of the ridge (4)
The lowering inclination angle (β) is preferably in the range of 30 to 90 °, which is a preferable practical range for thermally welding the lid material on the outer slope of the ridge. In addition, the height of the ridge line of the ridge, that is, the height (h) of the triangular apex generated when the flange portion was cut at a right angle to the direction of heat sealing, was that no ridge was provided on the surface of the flange portion. 0 from the flange surface assuming
5 to 3 mm is suitable for forming no wrinkles in the sealing portion of the lid material at the time of heat welding and for forming the two slopes (in the case of a sealed package having an inner volume of about 50 to 500 ml, When the flange width is 5 to 30 mm).

In the container for hermetic packaging according to the present invention, an inclined surface descending from the inner edge to the outer edge is provided on the surface of the flange portion as a heat sealing surface on which the lid material is to be heat-sealed on the flange portion. In the above method, the lid material is heat-welded to form a hermetically sealed package in which the peel strength from the inside of the lid of the sealed package is larger than the peel strength from the outside (in other words, the opening strength).

Such a condition is satisfied even if the triangular vertices shown in FIG. 1A are not strictly triangular vertices, or as shown in FIG. (A) Even if it is flat (b), it is satisfied as long as it has the inclined surface (3) to be a heat-sealing surface. This includes vertices that are flat or flat.

Further, the following various flange portions are provided from the essential feature of the present invention that the difference in peel strength between the inside and outside of the lid of the sealed package is provided by providing the inclined surface to be the heat sealing surface. Is possible.

First, for example, as shown in FIG. 3, the shape of the surface of the flange portion in the cross-sectional view starts from the outer edge portion (5) of the flange portion and proceeds horizontally, and then the heat sealing surface. After ascending the slope (3) to be traversed, it can proceed horizontally again without descending, and can take a structure directly connected to the container body (see Example 3 described later). In FIG. 3, reference numeral 6 denotes the position of the lid after heat sealing.

As shown in FIG. 4, the shape of the surface of the flange should be horizontal in the cross-sectional view, starting from the outer edge (5) of the flange, and then to the heat sealing surface. After ascending the slope (3), it is possible to take a structure in which it descends sharply in a curved line and is directly connected to the container body (see Example 4 described later). In FIG. 4, reference numeral 6 denotes the position of the lid after heat sealing.

Still further, as shown in FIG. 5, the shape of the surface of the flange portion in the cross-sectional view thereof starts from the outer edge portion (5) of the flange portion, progresses horizontally, and then becomes the heat sealing surface. After ascending the slope (3), passing through the apex (2) of the triangular shape and descending the slope (4), the situation shown in FIG. 1 is assumed. Instead, a structure that is immediately connected to the container body can be taken.

In all of these cases, the rising angle of the inclined surface (3) on the flange surface, in other words, the angle (α) at which the inclined surface (3) descends from the inner edge to the outer edge of the flange. Is 10 to 60 degrees, as in the case described with reference to FIG.

In FIG. 1A and FIGS. 2 to 5 described above, the slope (3) to be the heat sealing surface is a flat surface.

However, according to the knowledge underlying the present invention described above, it is clear that the slope (3) to be the heat sealing surface does not necessarily have to be flat. For example, the shape of the surface of the flange portion may not be a straight line but may be an upward or downward convex curve in the cross-sectional view thereof. This is shown in FIGS. 1 (b) and (c) corresponding to FIG. 1 (a). In the figure, the dashed line shows the case where the slope is flat for reference.

In short, as described above, in the hermetically sealed container of the present invention, the lid member is heat-sealed on the flange portion as a heat-sealing surface on the flange portion from the inner edge to the outer edge. The present invention is characterized in that a descending inclined surface is provided, and the lid material is heat-sealed on the inclined surface. All of the hermetically sealed containers satisfying such conditions are within the scope of the present invention. It is to be noted that this inclined surface does not need to be a plane as described above.

Those skilled in the art can easily produce a plastic container body having a slope to be a heat-sealing surface as described above on the surface of the flange portion, by those skilled in the art.

The material of the container body may be any polyolefin-based material, filler-filled material, vinyl chloride, or any other plastic which can be thermally welded. The heat sealing method can also be applied to hot plate welding, impulse sealing, high frequency sealing and the like.

The lid may be made of any material that can be welded between the container body and the opening flange, and the peel strength can be varied inside without special processing. In order to improve the properties, a so-called easy peel material is preferably used for the sealant layer.

The shape of the seal head for welding the lid material to the container body is not particularly limited as long as the lid material can be welded on the outer slope of the ridge of the heat sealing surface of the container body flange. There is no limitation, and for example, a seal head used for heat welding on a conventional flat surface may be used depending on the angle of the outer slope.

[0026]

The present invention will be further described below with reference to examples.

Example 1 The following experiment was conducted to set the direction of the tilt angle and the magnitude of the angle.

(A) A stainless steel inclined plate (upward inclination angle θ30 °, inclined length 10 cm) shown in FIG. 6 is prepared, and a gum tape 8 is adhered as shown in FIG. 6, and the peeling strength of the tape is reduced. It was measured with a force gauge. The adhesive length of the gum tape is l, m of three planes of the inclined plate shown in FIG.
And n were each 10 cm, and a load of 30 kg was uniformly applied to the entire surface of the adhesive at the time of adhesion. When peeling the gum tape from below upward, the tip of the length n of the gum tape adhesive surface on the plane below the inclined surface shown in the figure, and when peeling the gum tape downward from above, the adhesive surface on the inclined surface After the end of 1 was connected to the arm connected to the force gauge, the gum tape was pulled at a pulling speed of 300 mm / min such that the gum tape to be pulled always maintained a vertical direction, and the gum tape adhesive surface was peeled off. The measurement of the tensile strength with a force gauge was performed 10 times each while the distances of l, m and n were peeled off. The measurement accuracy was the average peeling strength ± 20%.

The peeling strength from the upper side to the lower side was about 1000 g weight at l and n in the upper and lower horizontal planes, about 2000 g weight on the inclined plane m, which was about double that on the horizontal plane. On the other hand, the peeling strength from below to above was about 1000 g weight for both l and n on the horizontal plane and m on the inclined plane.

The peel strength from the upper side to the lower side on the inclined surface corresponds to the peel strength from the inside of the container of the sealed package according to the present invention, and the peel strength from the lower side to the upper part is the peel strength from the outside ( Opening strength).

(B) When the same test was conducted with the upper inclination angle α changed to 60 °, the peeling strength from the upper side to the lower side was approximately the same in both upper and lower horizontal planes as in (a).
Although it weighed 1,000 g, it was about 4000 g weight on an inclined surface, about four times that of a horizontal surface. On the other hand, the peel strength from the lower side to the upper side was 1000 g weight as in (a) through both the horizontal plane and the inclined plane.

(C) From the results of (a) and (b) above,
The greater the angle of inclination of the heat sealing surface, the greater the peel strength (opening strength) from the outside of the lid in the sealed package, but the greater the peel strength from the inside, such as when internal pressure is generated during retort. Can be easily predicted.

(D) In the sealed packaging container of the present invention, it is important that the slope to be the heat sealing surface provided on the surface of the flange portion descends from the inner edge to the outer edge of the flange portion. As shown in FIG. 7, when it rises conversely (FIG. 3 '), as can be easily predicted from the results of (a) and (b) above, from the outside of the lid in the hermetically sealed package. Although it is difficult to open, the result is easy peeling from the inside, and the object of the present invention cannot be achieved. In order to confirm this prediction, the stainless steel inclined plate shown in FIG. 6 was turned upside down, and the peel strength was measured using the back surface according to the operation shown in (a) above.
In this case, since the inclined surface is downward from the outer edge toward the inner edge, the lower inclination angle is set to −θ with respect to the upper inclination angle θ.

The above (a) to (d) are summarized in Table 1 below.

[0035]

[Table 1]

(Embodiment 2) FIG.
150 ml of tap water is contained as a content in a polypropylene container body (sheet thickness 0.7 mm) containing a filler having the shape shown in (a), and a lid material (PET / AL / O-NY / PP) is placed outside the convex portion on the flange surface. Welding was performed on a slope (inclination angle α = 30 °) (seal condition: 210 ° C. × 1.5 seconds × 4 kg / cm) to produce a sealed package of the present invention.

From this sealed package, a right angle to the direction of heat sealing is obtained from 14 seal portions at the opening indicated by the arrow in FIG.
A test piece having a width of 15 mm was cut out and subjected to an openability test (seal strength measurement conditions: 15 mm width, tensile speed 300 mm / min). In FIG. 8, the arrow indicates the cutout position of the test piece in the opening, and the arrow pointing from the inside to the outside indicates that the test piece at that position measured the peel strength from the inside of the container, and from the outside to the inside. The arrow heading indicates that the opening strength of the test piece at that position was measured from the outside, and the numerical value listed at the base end of the arrow indicates the sealing strength (Kgf / 15 mm width).

As can be seen from FIG. 8, the peel strength from the inside of each of the seven places completely clears the seal strength regulation (2.3 kgf / 15 mm width) of the retort food to a large width (minimum).
3.4Kgf / 15mm width, average 4.6Kgf / 15mm width), while the maximum opening strength from the outside is 3.7Kgf / 15mm width, and the average is 2.2Kgf
/ 15 mm width, which confirms that the sealed package of the present invention has a good difference between the inside and outside peel strengths (the peel strength from the inside is significantly larger than the strength from the outside when opened).

Example 3 150 ml of tap water was contained as contents in a polypropylene container main body (sheet thickness 0.7 mm) having a filler having a cross section of the shape shown in FIG. 3 and a lid material (PET / AL / O). -NY / PP) was welded (seal condition: 210 ° C. × 1.5 seconds × 4 kg / cm) on the inclined surface (3) (inclination angle: 45 °) as a heat sealing surface to prepare a sealed package of the present invention.

A test piece having a width of 15 mm was cut out from this sealed package at a right angle to the direction of heat sealing from 14 seal portions of the opening indicated by an arrow in FIG. Tested (seal strength measurement conditions: 15mm
Width, tensile speed 300mm / min).

As a result, the peel strength from the inside of the seven places was determined by the seal strength regulation of the retort food (2.3 kgf).
/ 15mm width) completely clear (3.5Kgf / 15 minimum)
mm width, average 5.3 kgf / 15 mm width), while the maximum opening strength from the outside is 3.4 kgf / 15 mm width and average 2.1 kgf / 15 mm width. (The peel strength from the inside is remarkably large compared to the opening strength from the outside).

(Example 4) 150 ml of tap water was contained as contents in a polypropylene container body (sheet thickness 0.7 mm) containing a filler having a flange section having a cross section shown in FIG. 4, and a lid material (PET / AL / O). -NY / PP) was welded on the inclined surface (3) (inclination angle: 20 °) as a heat sealing surface (seal condition: 210 ° C. × 1.5 seconds × 4 kg / cm) to produce a sealed package of the present invention.

As in the case of Example 2, a test piece having a width of 15 mm was cut out from the sealed portion 14 at the opening indicated by an arrow in FIG. 8 at right angles to the direction of heat sealing. Tested (seal strength measurement conditions: 15mm
Width, tensile speed 300mm / min).

As a result, the peel strength from the inside of each of the seven locations was regulated by the seal strength regulation of the retort food (2.3 kgf).
/ 15mm width) completely (minimum 2.6Kgf / 15mm width,
On the other hand, the opening strength from the outside is 2.8 Kgf / 15 mm width and the average is 2.0 Kgf / 15 mm width, and the sealed package of the present invention has a good difference between inside and outside peeling strength (from outside). (The peel strength from the inside is remarkably large with respect to the unsealing strength).

[0045]

According to the present invention, unlike the high-level and high-cost methods of the prior art, an excellent (easy-opening) sealing method or (easy-opening properties) that is simple, low-cost, and can be adequately handled by conventional equipment. ) A sealed package can be provided.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view (conceptual view) of a flange portion of a container for hermetically sealed packaging according to the present invention.

FIG. 2 is a cross-sectional view (conceptual diagram) of the container flange portion for hermetic packaging of the present invention.

FIG. 3 is a cross-sectional view (conceptual diagram) of the flange portion of the container for hermetically sealed packaging according to the present invention.

FIG. 4 is a cross-sectional view (conceptual diagram) of the sealed packaging container flange portion of the present invention.

FIG. 5 is a cross-sectional view (conceptual diagram) of the flange portion of the container for hermetically sealed packaging according to the present invention.

FIG. 6 shows an outline of a test method in Example 1.

FIG. 7 exemplifies a flange portion whose heat sealing surface is an inclined surface opposite to that of the present invention.

FIG. 8 shows the results of an openability test in Example 2.

[Explanation of symbols]

 1. Flange part 2. Triangular vertex 3. Convex outside slope (slope as heat sealing surface) 3 '... Reverse slope 4. Convex inside slope 5. Flange outside edge 6 ..Position of heat-sealed lid material 7.Flange inner edge 8.Gum tape

Claims (3)

[Claims] 1. A plastic container main body having an opening flange portion to be heat-sealed with a lid member, wherein the surface of the flange portion has an inner edge to an outer edge at a position where the container main body is opened upward. A hermetically sealed container having a slope descending toward the bottom, wherein the descending slope is a heat sealing surface. 2. A plastic container body having an opening flange for heat-sealing a lid material, said flange having a projection having a triangular cross section on its surface. A container for hermetically sealed packaging, wherein the outer slope of the strip is a heat sealing surface. 3. A hermetically sealed package wherein the contents are stored in the container body according to claim 1 or 2, and a lid material is heat-welded to the container flange portion on the heat sealing surface.