JP2000309352A - Bag made of synthetic resin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To ensure a high seal tensile strength at a desired portion of a synthetic resin-make bag, prevent the bag from being peeled off and broken, and further keep a flexibility of the bag itself and various kinds of shutting functions. SOLUTION: Heat seal layers 40 provided at inner surface of the opposing two front and rear barrel films 1a, 1b are set as thin as possible as an entire bag. However, its seal tensile strength is set to have a range of 200 to 800 g/15 mm. A wall thickness of the heat seal layer for the desired portion of the heat seal requiring in particular the seal tensile strength is made thick to reinforce it and then the seal tensile strength of more than 200 to 800 g/15 mm is attained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a synthetic resin bag having a heat-sealed portion reinforced by a multilayer film having a heat-sealing layer on the inner surface of two facing body films. Things.

[0002]

2. Description of the Related Art A synthetic resin bag formed by heat-sealing three or four sides of a bag with a multilayer film having a heat seal layer on the inner surface of two facing body films is well known. .

[0003]

SUMMARY OF THE INVENTION A film in which a heat seal layer is thinly formed from a stretched film having heat sealability, a film having a resin coating on the surface of the film, or a multilayer film such as a co-extruded film. The seal tensile strength of the heat seal part is 200 to 80
When the thickness is set in the range of 0 g / 15 mm, although it can cope with the load to some extent, there is a surface which cannot completely prevent the occurrence of peeling and tearing at a specific location. That is, for example, when the bag body is used repeatedly, there is a problem that the seal portion peels and breaks due to the tensile force applied to the seal portions at both ends of the opening.

In order to solve this problem, the heat seal portion can be strengthened by increasing the thickness of the heat seal layer. However, in the bag body, the required sealing tensile strength is not uniform but is constant. There are cases where strong parts are required in some parts and not so strong in other parts. In such a case, if the thickness of the heat sealing layer is uniformly increased to enhance the sealing tensile strength, the flexibility of the bag itself is lost, and the bag is packed or stacked for display. However, there is a problem that the cost is high due to the lack of flexibility.

In order to maintain the flexibility of the bag itself, it is conceivable to secure the sealing strength and reduce the thickness of the film other than the heat sealing layer. This may lead to quality deterioration of the product.

SUMMARY OF THE INVENTION It is an object of the present invention to set a seal tensile strength of a heat seal layer within a necessary minimum range, and secure a strong seal tensile strength in a required portion requiring heat seal tensile strength. It is to provide.

[0007]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention relates to a synthetic resin bag formed by a multilayer film having a heat seal layer on the inner surface of two facing body films. The heat sealing layer is set so that the sealing tensile strength is in the range of 200 to 800 g / 15 mm, and the heat sealing portion which particularly requires the sealing strength is heat-sealed by strengthening the thickness. Is what you do.

Further, in a synthetic resin bag formed of a multilayer film having a heat seal layer on the inner surface of two facing body films, the heat seal layer has a seal tensile strength of 200 to 800 g / 15 mm. And the heat seal portions at both ends of the opening of the bag body are thickened and heat-sealed.

Further, in a synthetic resin bag formed of a multilayer film having a heat sealing layer on the inner surface of two facing body films, the heat sealing layer has a sealing tensile strength of 200 to 800 g / 15 mm. And heat-sealing the heat-sealing part by thickening the heat-sealing part of the pallet part, the hanging part, or the bottom part.

Furthermore, in a synthetic resin bag formed of a multilayer film having a heat seal layer on the inner surface of two facing body films, the heat seal layer has a sealing tensile strength of 200 to 800 g / g. 15mm
And a gusset portion formed of a multilayer film that is folded in a V-shape and has a heat seal layer on the surface in contact with the body film and is bonded to both sides or the bottom of the bag body. The gusset portion and the heat seal portion in the vicinity thereof are thickened and heat-sealed.

The thickening of the heat-sealed portion is provided as a projection or a strip connecting the left and right ends of the bag.

[0012] An occlusal tool of a concavo-convex type is provided on the inner surface on the opening side.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. The synthetic resin bag of the present invention is a multilayer film having a heat seal layer 40 set on the inner surface of two facing body films 1a and 1b facing each other so that the seal tensile strength is in the range of 200 to 800 g / 15 mm. Is a prerequisite component.

Examples of the multilayer film are as follows. However, it is not limited to this. (1) A thin heat seal layer (2-5μ)
m) is an integrally formed multilayer film, for example, a film made of polypropylene, polyester, saponified ethylene vinyl acetate copolymer, polyvinyl alcohol, or the like. (2) A multilayer film in which an adhesive resin is coated (0.5 to 2 μm) on one side or both sides of a stretched film, for example, polyvinylidene chloride-coated biaxially-stretched polypropylene or acrylic-coated biaxially-stretched polypropylene. Examples include a polyvinyl alcohol coat, an ionomer coat, a polyurethane coat, a polyamide coat, and a polyester coat. (3) The co-extruded multilayer film is a thin (3 to 10 μm) heat seal layer, for example, modified polypropylene / polypropylene / modified polypropylene, modified polypropylene / polypropylene / polyethylene, polypropylene / polyethylene / polypropylene, low density polyethylene / high density Polyethylene / low density polyethylene,
Polyester / polyethylene, polyvinyl alcohol /
Modified polypropylene and the like.

[0015]

EXAMPLE 1 As shown in FIGS. 1 and 2, a heat sealing layer 40 is set on the inner surfaces of two facing body films 1a and 1b so that the sealing tensile strength is in the range of 200 to 800 g / 15 mm. In the bag body 1 which is formed of a multilayer film having An arbitrary cross-sectional shape 1 that connects the left and right ends of the bag 1 to the opening 2 above the jaw 3
The protrusions 20 are provided, and both ends of the protrusions 20 are heat-sealed with the both side seals 5 to form a thick reinforcing portion 30.
Is formed. An opening notch 7 is engraved above the thickened portion 30, and the intended tearing direction is guided by the protrusion 20.

FIG. 3 shows a modification of the first embodiment, in which a strip 21 is used in place of the one projection 20 and both ends of the strip 21 are heat-sealed with both side seals 5 to strengthen the thickness. The portion 30 is formed.

[0017]

Second Embodiment FIGS. 4 and 5 show a second embodiment. The basic structure of the second embodiment is the same as that of the first embodiment. In the second embodiment, the protrusions 20 are formed by two upper and lower portions, and the two protrusions 2 are formed.
The two thickened portions 30 are formed by heat-sealing the two ends of both sides with the two side seals 5. An opening notch 7 is carved between the two projections 20 to guide an intended tearing direction between the two projections 20. In addition, the top seal 5a of the first embodiment is replaced with a bag-shaped opening. As shown in FIG. 5, the cross-sectional shape of the two protrusions 20 is square at the top and semicircular at the bottom, but as shown in FIG. 9, the top is square and the bottom is triangular. May be. The shape and the combination are arbitrary.

FIG. 6 shows a modification of the second embodiment, in which one projection 20 and a strip 21 are provided.
And the both ends of the band-shaped piece 21 are heat-sealed with the two side seals 5 to form the thickened portion 30.

[0019]

Third Embodiment FIGS. 7 and 8 show a third embodiment. In the third embodiment, a wide-width zipper tape 22 (a strip-shaped piece) is provided in the opening 2 above the jig 3, and both ends of the zipper tape 22 are heat-sealed with both side seals 5 to increase the thickness of the thickened portion 3.
0 is formed. An opening notch 7 is engraved above the chuck tape 22 to guide an intended tearing direction along the chuck tape 22.

[0020]

Fourth Embodiment FIGS. 11, 12 and 13 show a fourth embodiment. In FIG. 11, reference numeral 1 denotes a bag formed by two body films 1a and body films 1b facing each other, 2 denotes an opening, 3 denotes a jaw provided in the opening 2, and 4 denotes a film. It is a horizontal gusset (gusset portion) folded in a V-shape, is composed of a multilayer film having a heat seal layer on the surface in contact with the body films 1a and 1b, and is bonded to both sides 5 of the bag body 1. I have. This side gusset 4
The upper edge 4b of the horizontal gusset 4 has a length dimension in which the folding ridge line 4a is parallel to the line of the side 5 of the bag body 1 and the upper edge 4b of the horizontal gusset 4 is located below the jig 3. Is adhered 4c only to the inner surface of the one body film 1a side. The other body film 1b
It may be bonded to only one side of the two body films 1a, 1b.

The upper edge 4b of the horizontal gusset 4 is bonded only to the inner surface on the side of the one body film 1a, and has an adhesive property to the inner surface of the body film 1a and the inner surface of the horizontal gusset 4. They are adhered with a seal tape 8 (a strip). The sealing tape 8 is a series of tapes extending over the entire width L2 of the bag 1 including the side 5.

The sealing tape 8 has, on one side 8a, one side 8a of, for example, a linear low-density polyethylene having heat bonding property and a high melting point, and the other side 8b has a lower melting point than the one side 8a. And an inner film 11b of the horizontal gusset 4 and an inner film 10b of one of the body films 1a.
And a multi-layer of, for example, ethylene-vinyl acetate copolymer or low-density polyethylene having good heat adhesion. In the fourth embodiment, not only is the sealing tape 8 having heat sealing properties provided,
The gusset covered by the sealing tape 8 is strengthened by strengthening the thickness of the heat seal layer on one surface 8b.

[0023]

Fifth Embodiment FIGS. 14 and 15 show a fifth embodiment. The basic structure of the fifth embodiment is the same as that of the fourth embodiment. In the fifth embodiment, the sealing tape 8 (band-shaped piece) is a wide one in which the base portion of the jaw 3 on the female nail 3a side (or the male nail 3b side) is extended. The upper edge 4b is brought into contact with the inner surface of one of the body films, and is adhered. The base base itself has a multilayer structure, and an adhesive layer 8b for the body film and the horizontal gusset is considered. By doing so, the adhesion of the upper portion of the horizontal gusset and the vicinity thereof is strengthened.

In the figure, reference numeral 20 denotes a projection. As in the above-described embodiment, both ends of the projection 20 are heat-sealed by the two side seals 5 so that the thick reinforcing portions 30 are provided at both ends of the opening 2.
To form In the fifth embodiment, the horizontal gusset 4
The upper end edge 4b of the bag body may be brought closer to the opening 2 side than the jaw tool 3 to strengthen both ends of the bag opening.

[0025]

In the first embodiment, one projection 20 or a strip 21 is used. In the second embodiment, two projections 20 or one projection 20 and a strip 21 are used. In the third embodiment, a chuck seal tape 22 ( Example 4 is a sealing tape 8 (a strip), and Example 5 is a thick reinforcing portion 30 formed at one end by a single projection 20 and a sealing tape 8 with an occlusal tool (a strip). As shown in FIG. 10, both ends of the protrusion 20 provided on the thin heat seal layer 40 are pressurized by the two side seals 5 and heat-sealed to form the protrusion 2.
The both ends of 0 are melted and diffused to the periphery to form a thick sealing layer having a wide width W, and this becomes the thick reinforcing portion 30. In this operation, a thick sealing layer having a wide width W is formed in the same manner in the case of the strip 21, the chuck seal tape 22 (the strip) or the seal tape 8 (the strip), and the thick reinforcing portion 30 is formed.

Furthermore, as described in the fourth and fifth embodiments, the heat sealing layer of the sealing tape 8 (band-shaped piece) is considered (thickened), so that heat other than the side seals 5 can be obtained. The required portion of the seal (in this case, the gusset portion) also firmly increases the heat seal strength to prevent the bag from peeling and breaking.

[0027]

[Example of design change] In the case where the gusset portion is provided on the bag body, there is a method in which the heat sealing layer of the gusset portion itself is considered in addition to the method using the sealing tape as in the above embodiment. According to the method of strengthening the heat seal portion by making only the heat seal layer of the gusset itself relatively thicker than the main body, the effect of being somewhat inferior to the method using the seal tape in terms of maintaining the flexibility of the bag body It is possible to expect more advantages than the above-described method in terms of improving productivity and suppressing cost increase.

The case in which the gusset portion is provided on the bag body is generally not only provided on both sides of the bag body as in the above embodiment, but also provided on the bottom of the bag body for the purpose of self-support. Even in the latter case, peeling and breaking of the gusset portion becomes a problem, so it is desirable to strengthen the heat seal portion as described above.

Regarding the thickening of the heat seal portion,
Whether to adopt the form of the protruding portion or the form of the strip is appropriately selected in terms of the number and width. Of course, a mode in which the projection and the strip are used in combination may be selected. In short, a mode is considered in which a suitable heat sealing strength can be obtained for the required section.

In order to enhance the thickness of the heat seal portion, the form of a projection or a strip connecting the left and right ends of the bag is selected in consideration of the convenience of manufacture. However, the present invention is not limited to such an embodiment. It is not something to be done. For example, when the gusset portion is provided in the bag, the heat seal layer of the gusset itself is taken into consideration when the gusset portion is provided. good.

The heat-sealed portion of the support portion, the hanging portion, or the bottom portion is thickened as necessary. Thereby, the strength of the portion against the load can be enhanced. Further, in each of the above-described embodiments, the description has been made of the synthetic resin bag having the occluding tool, but the present invention can also be applied to a general bag without the occluding tool.

However, particularly in the case of a bag with an occlusal tool, both ends of the opening are liable to be damaged by rebound when opening the occlusal tool during repeated opening. As the thickness increases, the flexibility with respect to the internal and external pressures is reduced. In other words, the elasticity is liable to be affected by the internal and external pressures, and as a result, the jaw is opened by a slight impact. Therefore, it is preferable to consider the non-opening side of the jig so as not to lose its flexibility, that is, the overall thickening is problematic in such a case.

[0033]

As described above, according to the present invention, in a synthetic resin bag made of a multilayer film having a heat seal layer on the inner surface, the bag body has a thin heat seal layer having a minimum necessary sealing tensile strength. The heat seal layer is thickened and strengthened at the required portion of the bag body requiring the sealing tensile strength, and the bag is prevented from peeling and breaking from the portion. Specifically, especially in the opening part which is frequently opened and closed, the seal part at both ends is prevented from peeling and breaking, and the gusset part is reinforced by thickening the heat sealing layer of the gusset itself, or by using a sealing tape (band-like piece). By strengthening the cover of the gusset, peeling and breaking of the bag from the gusset is prevented, and the practicality is improved. In addition, since the heat seal layer is thin, the flexibility of the bag itself is maintained, so that the bag has flexibility when displayed in a box or stacked, and reduces the cost. Furthermore, the projections or strips serve as tear guides in the intended direction when tearing the opening and opening, and in addition to preventing tearing in unintended directions, the projections or strips remaining in the opening after tearing. The portion serves as a non-slip when the gripper is gripped with a fingertip to open the jaw, and the opening of the jaw is smooth.

[Brief description of the drawings]

FIG. 1 is a front view showing a bag according to a first embodiment of the present invention.

FIG. 2 is a sectional view taken along line AA of FIG. 1;

FIG. 3 is a sectional view taken along line AA of FIG. 1, showing a modification of the first embodiment;

FIG. 4 is a front view showing a bag according to a second embodiment of the present invention.

FIG. 5 is a sectional view taken along line BB of FIG. 4;

FIG. 6 is a sectional view taken along the line BB of FIG. 4 showing a modification of the second embodiment.

FIG. 7 is a front view showing a bag according to a third embodiment of the present invention.

8 is a sectional view taken along line CC of FIG. 7;

FIG. 9 is a cross-sectional view showing an example of the shape of a protrusion.

FIG. 10 is a cross-sectional view showing a thick reinforcing portion.

FIG. 11 is a front view showing Embodiment 4 of the bag of the present invention.

FIG. 12 is a sectional view taken along line EE of FIG. 11;

FIG. 13 is a sectional view taken along line DD of FIG. 11;

FIG. 14 is a front view showing Embodiment 5 of the bag of the present invention.

FIG. 15 is a sectional view taken along line GG of FIG. 14;

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 bag body 1a body film 1b body film 2 opening 3 jaw 4 side gusset 5 side seal 7 notch 8 seal tape (band-like piece) 20 projection 21 band-like piece 22 chuck tape (band-like piece) 30 thick reinforcing part 40 Heat seal layer

Claims (6)

[Claims] 1. A synthetic resin bag formed by a multilayer film having a heat sealing layer on the inner surface of two facing front and back body films, wherein the heat sealing layer has a sealing tensile strength of 200 to 800.
g / 15 mm, and a heat-sealing portion requiring particularly high sealing strength is thickened and heat-sealed to provide a heat-sealing portion. 2. A synthetic resin bag formed by a multilayer film having a heat sealing layer on the inner surface of two facing body films facing each other, wherein the heat sealing layer has a sealing tensile strength of 200 to 800.
The synthetic resin bag according to claim 1, wherein the thickness is set to be within a range of g / 15mm, and the heat seal portions at both ends of the opening of the bag are strengthened and heat-sealed. 3. A synthetic resin bag formed by a multilayer film having a heat seal layer on the inner surface of two facing front and back body films, wherein the heat seal layer has a sealing tensile strength of 200 to 800.
g / 15 mm, and heat-sealing by thickening and strengthening the heat-sealing portion at the grip portion, the hanging portion, or the bottom portion. Synthetic resin bag. 4. A synthetic resin bag formed by a multilayer film having a heat sealing layer on the inner surface of two facing front and back body films, wherein the heat sealing layer has a sealing tensile strength of 200 to 800.
g / 15 mm, and a gusset made of a multilayer film which is folded in a V-shape on both sides or the bottom of the bag and has a heat seal layer on the surface in contact with the body film, and is bonded. 4. A synthetic resin bag according to claim 1, wherein a gusset portion or a heat seal portion in the vicinity thereof is heat-sealed by thickening. 5. The synthetic resin bag according to claim 1, wherein the thick wall of the heat seal portion is formed as a protrusion or a strip connecting the left and right ends of the bag. 6. The synthetic resin bag according to claim 1, further comprising a concave-convex occlusal type jaw on the inner surface of the opening.