JPH11193054A - Pressure regulating body for packaging container - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a packaging container from exploding and breaking even when a pressure which cannot be allowed is generated in the internal space of the packaging container, and prevent various kinds of bacteria and bugs or the like from entering the packaging container from the outside by a method wherein an adhesive layer is provided on the rear surface of an anti-stress relaxing sheet, and at the same time, a slit is provided on the anti-stress relaxing sheet. SOLUTION: For this pressure regulating body 1, on the rear surface of an anti-stress relaxing sheet 3 where a slit 2 is formed, an adhesive layer 4 is provided. The pressure regulating body 1 is used by affixing it on a ventilation port 11 which is formed on a packaging container 10 in a manner to cover the ventilation port 11 with the adhesive layer 4. The anti-stress relaxing sheet 3 which is used for the pressure regulating body 1 is constituted of a material equipped with an anti-stress relaxing property by which the slit 2 formed on the sheet 3 is normally closed, and the slit 2 is opened when a pressure exceeding an allowable value is applied from the inside of the packaging container 10, and the slit 2 returns to the original closed state when the pressure returns to the allowable value or less. The anti-stress relaxing property is preferable to be 40% of the tensile stress relaxing rate Rr (24 hours) to 100% of Rr (24 hours).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention has an object to provide a pressure regulator for a packaging container capable of preventing the packaging container from being ruptured or damaged even when an unacceptable internal pressure is generated in the internal space of the packaging container. And

[0002]

2. Description of the Related Art If a hermetically sealed packaging container such as a packaging bag for food such as confectionery is directly heated in a microwave oven, unacceptable pressure is applied to the internal space of the packaging container due to expansion of air inside the packaging container. May burst or break. In addition, when the roasted coffee is filled into a sealed packaging container, carbon dioxide is generated from the roasted coffee, so that an unacceptable pressure is applied to the internal space of the packaging container and the packaging container bursts. , And could be damaged. As a method of solving this problem, a method of opening an arbitrary vent in the hermetically sealed packaging container or a method of making the sealing of the packaging container incomplete have been adopted. Although this method is very simple, it has a disadvantage that various bacterial species, insects, and small animals enter through the vent and contaminate the food in the packaging container. Therefore, as disclosed in Japanese Patent Publication No. 59-34585, a pressure valve device composed of a composite layer of a flexible sheet and an adhesive layer is attached to a packaging container, whereby air inside the sealed packaging container expands. Methods have been proposed in which the resulting unacceptable pressure in the interior space of the packaging container is equivalent to the external pressure.

[0003]

However, the above-mentioned method using a pressure valve can prevent various bacterial species, insects, and small animals from entering from outside the packaging container by using a pressure valve that closes an air vent. In addition to the complicated structure, the pressure valve is basically in communication with the outside, so that a special means must be added to prevent oxidation. The present invention has been made in view of the drawbacks of the related art, and even when a pressure that cannot tolerate the internal space of the packaging container due to the expansion of air inside the packaging container is applied, the packaging container is ruptured and damaged. It is an object of the present invention to provide a pressure regulator for a packaging container which can prevent various kinds of bacteria, insects, small animals, and the like from entering the ventilation container from outside the packaging container.

[0004]

SUMMARY OF THE INVENTION In order to achieve the above object, a pressure regulator for a packaging container according to the present invention is provided with an optional pressure regulating device for the packaging container to equalize the pressure inside the packaging container with the pressure outside the packaging container. A pressure regulator used to cover an open vent, wherein an adhesive layer is provided on the back surface of the stress relaxation sheet, and a slit is provided in the stress relaxation sheet. In the pressure regulator of the packaging container according to the second aspect, the stress relaxation resistant sheet has a tensile stress relaxation rate Rr (24) of 40% or more.
Further, the pressure regulator of the packaging container according to claim 3 is characterized in that the stress relaxation resistant sheet is a self-adhesive material.
Further, in the pressure regulator of the packaging container according to claim 4, the stress relaxation-resistant sheet has a two-layer structure with an adhesive layer interposed therebetween, and the slit is provided at a communication position through the adhesive layer. Features. According to a fifth aspect of the present invention, in the pressure adjusting body for a packaging container according to the fourth aspect, the adhesive layer on the back surface is removed at a peripheral portion of the slit.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIGS. 1 and 2 are cross-sectional views schematically showing one embodiment of a pressure regulator of a packaging container according to the present invention, wherein 1 shows a pressure regulator and a slit. 2, an adhesive layer 4 is provided on the back surface of the stress relaxation resistant sheet 3 on which
FIG. 2 shows a state in which the adhesive layer 4 is adhered so as to cover the ventilation port 11 formed in the packaging container 10 via the adhesive layer 4.

FIG. 7 is a cross-sectional view schematically showing another embodiment of the pressure regulator of the packaging container of the present invention.
In the figure, reference numeral 1 denotes a pressure regulator, and the stress relaxation-resistant sheet 3
With a two-layered stress-relief sheet 3 with an adhesive layer 5
3, the slit 2 is provided at a communicating position via the adhesive layer 5, and various kinds of bacteria, insects, small animals, etc. can be vented from outside the packaging container 10 by the interposition of the adhesive layer 5 between the slits 2, 2. This makes it possible to surely prevent entry from 11. As shown in FIG. 8, when the adhesive layer 4 on the back side is removed from the periphery of the slit 2 as shown in FIG. 8, various bacterial species, insects, small animals, etc. enter from the vent 11 from outside the packaging container. In addition, it is possible to reliably prevent the rupture and breakage of the packaging container.

[0007] As shown in FIG. 1, the stress relief sheet 3 used in the pressure adjusting body 1 has a slit 2 formed in the sheet 3 which is always closed.
As shown in FIG. 2, when a pressure exceeding the allowable value is applied from within 0, the slit 2 opens, and when the pressure returns to within the allowable value, the slit 2 returns to its original closed state. It is necessary to be composed of a material having For example, polyethylene, polypropylene, polyvinyl chloride, polyester, polyacrylate, polyacrylic acid, polymethacrylate, polymethacrylic acid, polyamide,
Polymer compounds such as ethylene-vinyl acetate copolymer, ethylene-acrylate copolymer, polyvinyl acetal, polyvinyl butyral, atactic polypropylene, ethyl cellulose, cellulose triacetate, hydroxypropyl cellulose, polyphosphazene, natural rubber and poly Isobutylene, acrylonitrile-butadiene copolymer, styrene-isoprene block copolymer,
It is preferable to use various synthetic rubbers such as polybutadiene, silicone rubber, urethane rubber, fluorine rubber, nitrile rubber, butyl rubber, ethylene-propylene rubber, styrene-butadiene rubber, chloroprene rubber, and various thermoplastic rubbers.

The stress relaxation resistance of the pressure regulator according to the present invention can be evaluated by using JIS K6263. The shape and dimensions of the test pieces are specified in 4.3 of JIS method K6263.
1. Sample width 10 mm, total length 60 mm, distance between grips 20
mm, according to the strip-shaped No. 2 type. Here, regarding the thickness of the sample piece, the stress relaxation resistance was evaluated based on the thickness of the stress relaxation resistant material actually used. Unless otherwise specified, the test temperature was 23 ± 1 ° C., the test time was 24 hours, and the tensile strain was 5%. The tensile stress relaxation rate Rr (t) can be represented by the following equation. Rr (t) = {F ₀ −F (t)} / F ₀ × 100 = {f ₀
−f (t)｝ / f ₀ × 100 where Rr (t): tensile stress relaxation rate after t time (%) F ₀ : initial tensile force (N) F (t): tensile force after t time (N) f ₀ : Initial stress (MPa) f (t): Tensile stress after t time (MPa) The tensile stress relaxation rate is usually expressed as Rr (24) 80%. Here, (24) indicates the test time of 24 hours,
80% represents the measurement result. The tensile stress relaxation rate determined under the above conditions was used as an evaluation standard for stress relaxation resistance of the pressure regulator according to the present invention. The stress relaxation resistance of the pressure regulator according to the present invention is preferably in the range of 40% Rr (24) to 100% Rr (24), and more preferably 60% Rr (24) to 100% Rr (24). Is preferable. When the stress relaxation resistance is less than 40% of Rr (24), the pressure inside the packaging container can be made equal to the pressure of the outside air. After being deformed and opened, it cannot be closed again because of its low stress relaxation resistance. After the pressure regulating body is deformed, at least Rr (2
4) A stress relaxation resistance of 40% or more, preferably 60% or more of Rr (24) is required. Further, this pressure adjusting body may be adhered to the inside of the closed packaging container 10 so as to cover the ventilation port 11 opened in the closed packaging container 10.

When a self-adhesive material such as polyvinyl chloride, polyurethane, polyvinyl butyral, and silicone resin is used, the confidentiality in the closed state of the slit 2 can be improved. Is preferred. Further, the material having stress relaxation resistance according to the present invention may be, if necessary, a pigment, a dye, a coloring agent such as carbon, a plasticizer such as dioctyl naphthalate and dibutyl sebacate, titanium oxide, zinc oxide, and zirconium oxide. , Aluminum oxide, calcium oxide, calcium carbonate, inorganic fine powders such as silica, higher fatty acids, polyvinylidene fluoride,
Organic fine powder such as polyethylene, iron, copper, aluminum,
Metal powders such as cobalt, nickel, and silver, and further, a weather resistance improver and a light resistance improver can be added. It should be noted that the present invention is not limited by these specific examples.

The vent 11 formed in the packaging container 10
As shown in FIGS. 3 (a) to 3 (j), any shape and size are selected according to the contents to be housed in the packaging container 10. As shown in FIG. 4A to FIG.
According to the shape of the container, the allowable value of the internal pressure in the packaging container 10, the shape and dimensions of the vent 11 formed in the packaging container 10,
Arbitrary shapes and dimensions are selected. In other words, as long as the shape and dimensions are such that they are always kept closed, open when the internal pressure exceeds the allowable value, and return to the closed state when the internal pressure returns to the allowable value, any shape and size Things are selected.

The adhesive constituting the adhesive layer 4 may be polyvinyl chloride, polyurethane, polyester,
Examples include polyacrylic acid ester, polyacrylic acid, polymethacrylic acid ester, polymethacrylic acid, polydimethylsiloxane, polystyrene, polycarbonate, polyamide, and epoxy resin.

[0012]

EXAMPLES The present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples. First, an evaluation device and an evaluation method for a pressure regulator according to the present invention will be described with reference to FIG. FIG. 9 shows a pressure evaluator, which has an opening on one side, a thickness of 5 mm,
Two cylindrical stainless steel chambers 12a and 12b having a diameter of 50 mm and an internal volume of 500 cm ³ were prepared. The opening surface was adjusted to the opening surface to improve the sealing, width 2 mm,
2 mm thick polyisopropylene rubber packing 13
a and 13b were attached. Each chamber 12
Digital pressure gauges 14a and 14b are attached to the first and second chambers 12a and 12b to evaluate the internal pressure.
Was provided with a gas inlet 16 from an air compressor 15. This was used as a pressure evaluation device. A sample consisting of a packaging container 10 to which the pressure regulator 1 is attached is placed in a chamber 12a, 1
The mold was cut out in accordance with the opening surface of the chamber 2b, and the sample was attached to the opening surface of the chamber 12a. Then, the sample was fitted and fixed to the opening surfaces of the two chambers 12a and 12b via the packings 13a and 13b. The evaluation of the pressure regulator 1
After fixing the sample, the internal pressure of both chambers 12a and 12b was set to 1020 hPa, and the gas inlet 1
Air was introduced from 6 by an air compressor 15 to increase the internal pressure of the chamber 12b, and two minutes later, the pressure in each of the chambers 12a and 12b was measured. As the packaging container 10, a packaging container 10 made of a polyethylene terephthalate film having a diameter of 50 mm and a thickness of 25 μm and having a ventilation opening 11 opened by an etching plate was used.

(Example 1) Rr (24)
Stress relaxation resistant sheet 3 obtained by cutting a urethane rubber having a thickness of 75% and a thickness of 80 μm into a circle having a diameter of 2.54 cm.
Then, a pressure-sensitive adhesive containing polyacrylic acid n-butyl ester as a main component was applied to a thickness of 20 μm to form an adhesive layer 4. The slit 2 was opened by an etching plate on the stress relaxation-resistant sheet 3 on which the adhesive layer 4 was formed, and the pressure regulator 1 was formed. This was affixed so as to completely cover the vent 11 of the previously prepared packaging container 10, and was adhered by applying pressure. This sample was fixed to the pressure evaluation device,
The pressure inside each of the chambers 12a and 12b is set to 1020
Hectopascal. Next, the internal pressure of the chamber 12b on the side of the gas inlet 16 was increased to 1250 hPa. After 2 minutes, the respective chambers 12a, 1
When the pressure in 2b was measured, both were 1250 hPa. Thereafter, the internal air was allowed to flow off from the gas inlet 16 and the pressure in the chamber 12b on the gas inlet 16 side was adjusted to 1020 hPa.
Two minutes later, when the pressure in the pair of chambers 12a was measured, it remained at 1250 hPa (FIGS. 5, 6, and 9).
reference).

(Example 2) The stress relaxing material of Example 1 was changed to silicone rubber having a thickness of Rr (24) 70% and 80 μm, and the pressure regulator 1 was manufactured in the same manner as in Example 1. Created. This sample was fixed to a pressure evaluation device, and the pressure in each of the chambers 12a and 12b was set to 1020 hectopascal. Next, the internal pressure of the chamber 12b on the gas inlet 16 side was increased to 1150 hPa. Two minutes later, the respective chambers 12a and 12b
The internal pressure was measured to be 1150 hPa. Thereafter, the internal air was made to flow away from the gas inlet 16 and the pressure in the chamber 12b on the gas inlet 16 side was adjusted to 1020 hPa. Two minutes later, the pressure in the pair of chambers 12a was measured.
130 hectopascals.

(Embodiment 3) Rr (24)
Two 90% polyester sheets 3 and 3 each having a thickness of 50 μm and 25 μm, respectively, through an adhesive layer 5 made of a pressure-sensitive adhesive mainly composed of n-butyl polyacrylate having a thickness of 20 μm. A two-layer structure, which is cut into a circle having a diameter of 2.54 cm, is provided on one surface (on the side of the polyester sheet having a thickness of 25 μm) of the stress relaxation resistant sheets 3 and 3 with n-butyl polyacrylate as a main component The resulting pressure-sensitive adhesive was applied to a thickness of 20 μm to form an adhesive layer 4. On the surface of the stress relaxation resistant sheets 3, 3 on which the adhesive layer 4 is formed, on which the adhesive layer 4 is not formed, at a communication position via the adhesive layer 5 interposed between the sheets 3, 3,
The slits 2 and 2 were opened by the etching plate to prepare the pressure regulator 1 (with the configuration shown in FIG. 7). This sample was fixed to the pressure evaluation device, and the pressure in each of the chambers 12a and 12b was set to 1020 hPa. Next, the internal pressure of the chamber 12b on the gas inlet 16 side was increased to 1200 hectopacal. Two minutes later, the pressure in each of the chambers 12a and 12b was measured and found to be 1200 hPa. Then, the internal air is caused to flow off from the gas inlet 16,
The pressure of the chamber 12b on the gas inlet 16 side is increased to 1020.
Adjusted to be hectopascal. Two minutes later, the pressure in the pair of chambers 12a was measured and found to remain at 1200 hPa.

(Embodiment 4) Rr (24)
Two 90% polyester sheets 3 and 3 each having a thickness of 50 μm and 25 μm, respectively, through an adhesive layer 5 made of a pressure-sensitive adhesive mainly composed of n-butyl polyacrylate having a thickness of 20 μm. A two-layer structure was formed, and this was cut into a circle having a diameter of 2.54 cm to obtain a stress relaxation resistant sheet. A slit 2 having a length of 5 mm was opened at the center of the stress relaxation-resistant sheet (the side of the polyester sheet having a thickness of 50 μm) by an etching plate.
A pressure-sensitive adhesive mainly composed of n-butyl polyacrylate having a thickness of 25 μm
(Polyester sheet side of FIG. 8) A pressure adjuster 1 was formed by applying a circle having a diameter of 7 mm from the center to form an adhesive layer 4 around the slit 2 where no pressure-sensitive adhesive was applied (see FIG. 8). thing). This sample was fixed to the pressure evaluation device, and the pressure in each of the chambers 12a and 12b was set to 1020 hPa. Next, the internal pressure of the chamber 12b on the side of the gas inlet 16 is increased to 132
0 hectopalccal. Two minutes later, the pressure in each of the chambers 12a and 12b was measured.
It was 320 hPa. Then, gas inlet 1
6, the internal air was made to flow away, and the pressure in the chamber 12b on the gas inlet 16 side was adjusted to 1020 hPa. Two minutes later, the pressure in the pair of chambers 12a was measured and found to be 1320 hPa.

COMPARATIVE EXAMPLE 1 The stress relaxation-resistant sheet of Example 1 was replaced with a 30% Rr (24), 80 μm thick vinyl acetate / butyl acrylate copolymer having no stress relaxation resistance. The pressure regulator 1 was prepared in the same manner as in Example 1 except that the pressure regulator 1 was changed. This sample was fixed to a pressure evaluator, and the pressure in each of the chambers 12a and 12b was set to 10
It was 20 hPa. Next, the internal pressure on the chamber 12b side on the gas inlet 16 side was increased to 1250 hPa. After 2 minutes, each chamber 12
When the pressures inside a and 12b were measured, both were 1250.
Hectopascal. After that, the internal air is caused to flow away from the gas inlet 16 and the chamber 1 on the gas inlet 16 side.
The pressure of 2b was adjusted to 1020 hPa. Two minutes later, the pressure in the pair of chambers 12a was measured to be 1020 hPa. As a result of comparing Examples 1 to 4 with Comparative Example 1, the pressure regulator used in Examples 1 to 4 makes the pressure inside the packaging container equivalent to the pressure of the outside air, and further increases the confidentiality inside the packaging container. I found that I could do it. However, when a material having low stress relaxation resistance is used for the pressure regulator as in Comparative Example 1, the pressure regulator is deformed due to an increase in the pressure inside the packaging container, and after opening, the stress relaxation resistance is low. Will never close again. As a result, it was found that it was impossible to increase the confidentiality inside the packaging container.

[0018]

As described above, according to the present invention, an unacceptable pressure is applied to the internal space of the packaging container due to the expansion of the air inside the packaging container, thereby preventing the packaging container from being ruptured or damaged. A pressure regulator for a packaging container is obtained that can prevent various bacterial species, insects, small animals, and the like from outside the container from entering through the vent. In particular, when the stress relaxation-resistant sheet has a two-layer structure with an adhesive layer interposed therebetween and the slit is provided at a communication position through the adhesive layer, various types of bacteria, insects, A pressure regulator for a packaging container that can reliably prevent small animals and the like from entering through the vent is obtained. Further, in this case, if the adhesive layer on the back side is removed at the periphery of the slit, various bacterial species, insects, small animals, etc. from outside the packaging container can be reliably prevented from entering from the vent, and the packaging container can be prevented. A pressure regulator that can reliably prevent rupture and breakage of the pressure regulator can be obtained.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view schematically showing an embodiment of a pressure regulator (closed state) of a packaging container of the present invention.

FIG. 2 is a cross-sectional view schematically showing an embodiment of the pressure regulator (opened state) of the packaging container of the present invention.

3 (a) to 3 (j) are plan views of vents arbitrarily opened in a packaging container using the pressure regulator of the packaging container of the present invention.

FIGS. 4A to 4F are plan views of slits formed in a pressure adjusting body of the packaging container of the present invention.

FIG. 5 is a plan view of an embodiment of the pressure regulator of the packaging container of the present invention.

FIG. 6 is a perspective view of an embodiment of the pressure regulator of the packaging container of the present invention.

FIG. 7 is a cross-sectional view schematically showing another embodiment of the pressure regulator (closed state) of the packaging container of the present invention.

FIG. 8 is a cross-sectional view schematically showing still another embodiment of the pressure regulator (closed state) of the packaging container of the present invention.

FIG. 9 is a front view of the evaluation device for the pressure regulator of the packaging container of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Pressure regulator 2 Slit 3 Stress relaxation sheet 4 Adhesive layer 5 Adhesive layer 10 Packaging container 11 Vent 12a, 12b Chamber 13a, 13b Packing 14a, 14b Digital pressure gauge 15 Air compressor 16 Gas inlet

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI B65D 81/34 B65D 81/34 V

Claims (5)

[Claims] 1. A pressure adjuster used to cover a ventilation port arbitrarily opened in the packaging container so as to make the pressure inside the packaging container equivalent to the pressure outside the packaging container, wherein the stress relaxation-resistant sheet is used. A pressure-adjusting body for a packaging container, wherein an adhesive layer is provided on the back surface of the container and a slit is provided in the stress relaxation-resistant sheet. 2. The pressure regulator for a packaging container according to claim 1, wherein the stress relaxation-resistant sheet has a tensile stress relaxation rate Rr (24) of 40% or more. 3. The pressure regulator of a packaging container according to claim 1, wherein the stress relaxation-resistant sheet is a self-adhesive material. 4. The stress relief sheet according to claim 1, wherein the sheet has a two-layer structure with an adhesive layer interposed therebetween, and the slit is provided at a communication position with the adhesive layer interposed therebetween. A pressure regulator for a packaging container according to any of the claims. 5. The pressure regulating body for a packaging container according to claim 4, wherein the adhesive layer on the back side is removed at a peripheral portion of the slit.