JP2008280054A - Degassing valve for package and manufacturing method of the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a degassing valve and a manufacturing method of the same that opens at a low inside pressure while ensuring a positive sealing function as a valve which is a degassing valve for discharging excessive gas inside a package, does not require a complicate application of oil immediately before the adhesion of the valve, is easy to use, saves amount of materials used, and reduces burdens of saving resources and burdens for environment. <P>SOLUTION: Recessed portions are continuously formed in a plastic sheet at both of the outer circumference and the inner circumference, the recessed portion having a flat portion at a bottom surface, and the flat portion having liquid pool. An air hole is formed in a center portion of the plastic sheet, and after that, a liquid having a sealing function is applied onto the flat portion. A valve film punched in a shape of the recessed portions is stacked onto the plastic sheet so as to cover the liquid-coated flat portion and the air hole. Then, the outer circumference is punched out leaving a flange portion for adhering to the package. Each of the degassing valves, supplied into a filling package machine in a continuous tape shape, is cut off from the tape, and is adhered to the package by melting or adhesive. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a degassing valve for suppressing excessive internal pressure by sticking to a package and letting the gas inside the package escape.

[Prior art and its problems]
Contents that excessively increase the pressure inside the package due to the gas generated during storage, such as roasted coffee beans, agricultural chemicals, miso, etc., and packaging bags that are cooked such as bento and side dishes Alternatively, a valve label having a degassing mechanism has been proposed for packaging containers.

  For example, JP-A-56-32244 discloses that a valve sheet, a cover film, and a reinforcing sheet are laminated with an adhesive on a substrate sheet provided with an adhesive layer and covered with a release liner, and then half-cut into a circle or a rectangle. Valve labels have been proposed. When the pressure of the air in the packaging bag with the valve label affixed to the outer surface with an adhesive increases, the gap surrounded by the valve substrate and the valve film opens, and the air in the bag is perforated by the bag. It is a mechanism that discharges to the outside through the air hole of the valve label board that communicates, and after releasing the air, it is possible to shut off the air from the outside by the silicone oil interposed in this gap, so the valve function is obtained. It is done.

  However, the valve label by this method may cause the silicone oil to ooze out from the gap between the substrate and the valve film and impair the stickiness, making it difficult to stick to the packaging bag. There is a need to apply oil. In addition, since the amount of oil is kept low so that the applied oil does not stain the adhesive surface before the applied oil oozes and is applied, the surface tension due to the oil between the substrate and the valve film tends to be high, and the pressure at which the valve opens There is a disadvantage that (open pressure) becomes high.

  As a solution to this drawback, there is a degassing valve that is used by inserting a film or sheet into a recess formed by injection molding with silicone oil interposed therebetween to provide a valve function, and by thermally welding the outer periphery to the inner surface of the packaging film. Are known. However, in injection molding, there is a limit to thin molding, so the thickness of parts increases, the amount of material used increases, and cooling takes time, resulting in poor productivity and high price. is there. Moreover, since thickness is as thick as about 4 mm, a protrusion | protrusion becomes a problem and is not used when sticking on the outer surface of a package.

As a solution to these problems, the present inventor has provided a valve label in Japanese Patent Application Laid-Open No. 2006-298410 that requires less material usage by thermoforming a plastic film or sheet. However, the present invention is further simplified. The base film is omitted, and in addition, it is improved so that it can be used by being attached to both the inner and outer surfaces of the package.
JP 56-32244 JP 2006-298410 A

  The present invention has been made to solve the above-described problems. The valve is opened even at a low internal pressure while ensuring a reliable sealing function as a valve, and the valve purchaser immediately before applying the oil The purpose is to provide a degassing valve for packaging and a method for manufacturing the same, which can save the amount of material used without the complexity of having to apply, and contribute to resource saving and reduction of environmental burden And

  In this invention, a flat part having a liquid reservoir and an air hole are provided on both the outer periphery and the inner periphery on the bottom surface of a recess formed in a plastic sheet, and a liquid having a sealing function is applied onto the flat part, and from above The present invention provides a gas venting valve in which a valve film is laminated so as to cover a flat portion and an air hole, and is formed so as to be fixed to a package by a flange portion on the outer periphery of a concave portion.

  Furthermore, a step of continuously forming a recess having a flat portion having a liquid reservoir on both the outer periphery and the inner periphery on the bottom surface in a plastic sheet, a step of punching air holes, and a liquid having a sealing function A process of applying on the flat part, a process of laminating the valve film punched in conformity with the shape of the concave part so as to cover the flat part and the air hole to which the liquid is applied, and fixing the outer periphery of the concave part to the package The manufacturing method of the valve for gas venting which consists of the process of punching leaving the flange part of is provided.

  According to the present invention, a thin plastic sheet can be used to continuously perform the steps of forming the recesses, punching the air holes, applying the liquid, and laminating the valve film. Productivity is high compared to, and material consumption can be saved. Further, since the liquid having a sealing function is applied in advance, there is no trouble that the purchaser of the valve has to apply the oil immediately before application. Even when the sealing liquid to be applied to the flat part is excessively applied, the excess liquid stays in the liquid reservoir and does not flow out to the flange part. Compared with this, a larger amount of sealing liquid can be applied, so that the opening pressure can be lowered. Furthermore, by changing the bottom shape of the recess, the base film used in JP-A-2006-298410 is omitted, and the valve film is laminated directly on the flat portion of the recess, so that the process can be simplified and the materials used can be saved. Furthermore, since the bottom part shape of the concave part is a flat part, a liquid reservoir, and a simple shape of the air hole, the thickness of the valve can be reduced, and it can be attached to the outer surface of the package. Since it is continuously formed into a thin sheet, it can be supplied in a continuous tape form, and can be separated and pasted in the filling and packaging machine process, simplifying the pasting process and parts feeders used in injection molded products The apparatus for aligning is not necessary. The air inside the package enters the valve from the air hole in the recess, passes through the gap between the valve film and the flat portion, and is released, so that excessive pressure generated inside the package is eliminated. Since the external air is blocked by the liquid having a sealing function interposed between the base film and the valve film and cannot flow into the bag, the contents can be protected from oxidation and moisture absorption.

The degassing valve of the present invention can be attached to both the inner surface and the outer surface of the package simply by changing the outer peripheral flange shape. The degassing valve for inner surface sticking can be attached by heat-welding the upper flange part of the outer periphery of the recess to the package, so there is no need for a release liner to be discarded when sticking with adhesive, saving resources and environment It is possible to contribute to reducing the load. As for the degassing valve for outer surface sticking, a method of sticking to the outer surface of the package body using an adhesive is often used. However, although there is a demerit that requires a release liner, it can be applied to packages of various surface substrates. In addition, there is a merit that it can be easily applied only by pressure bonding without using a heat seal device.
As described above, according to the present invention, a simple degassing valve and a method for manufacturing the same, in which the drawbacks of the conventional methods are solved, are provided, which can contribute to saving resources and reducing the burden on the environment.

Embodiments of the venting valve and the manufacturing method thereof according to the present invention will be described.
FIG. 1 shows a schematic view and a sectional view of a degassing valve used by being attached to the inner surface of the package.
As a plastic sheet 1 for forming the recess 2, a single-layer or multi-layer sheet of relatively rigid plastic such as polypropylene, polyester, polystyrene, polycarbonate, etc. having a thickness of 150 μm to 600 μm is used for welding to a package. Uses a sealant layer of 20 to 50 μm if necessary. The concave portion 2 has a circular shape with a diameter of 10 to 30 mm or a rectangular shape with a similar bottom area, and can be formed using a general-purpose forming method such as vacuum forming or a forming method using a press die. If the sheet is too thin, the recesses are easily deformed, and a thick sheet is not only economical but also uneconomical. The bottom surface of the recess is provided with a flat portion 5 and liquid pools 4 and 6 on the inner and outer circumferences thereof. The unevenness on the bottom surface prevents the excessively applied liquid from flowing out to the flange portion and prevents liquid from flowing into the flat portion. Although there is an effect of reinforcing the rigidity of the bottom surface at the same time, the necessary strength can be obtained with a thinner sheet. The flat portion 5 forms an air passage with the valve film 8 that is covered with the sealing liquid 7 and prevents the ingress of external air. Therefore, the flat portion 5 needs to be flat with the valve film. The width of the flat portion 5 corresponding to the length is desirably 2 mm to 8 mm. If this width is short, the contact between the valve film and the flat part is difficult to be maintained when the recess is deformed, and there is a risk of the entry of external air. Conversely, if it is too long, the valve becomes large and more material is required. Not only will the pressure (opening pressure) in the package in which the valve operates become higher. A surface tension is exerted between the valve film 8 and the flat portion 5 by closely interposing the sealing liquid 7 in the gap, and the pressure of the air entering from the air hole 3 in the recess is included in the surface tension. When this happens, air passes through the gap between the valve film and the flat portion, and excess air in the package is released. The surface tension increases as the length of the flat portion increases and the gap between the valve film and the flat portion (the thickness of the intervening liquid) decreases, so that the open pressure, that is, the valve functions to release air. As a result, the pressure to start releasing excessive air in the package becomes high. This is why the opening pressure increases when the amount of the interstitial sealing liquid is small. The shallower the depth of the concave portion, the smaller the thickness of the sheet. However, the valve film laminated over the flat portion does not hinder the movement of releasing air, and considering the accuracy of the molding process and the rigidity of the sheet, it is 0. It is desirable to select a range of 3 to 3 mm. The shape of the air hole 3 provided on the bottom surface of the recess can be variously changed and the hole diameter can be selected according to the amount of air to be discharged, but in the case of a 150 to 500 g coffee bean packaging bag, a 1 to 8 mm hole is provided in the center. Individual holes are drilled, or holes of 2 mm or less are drilled at a plurality of locations to form air passages in the bag. When a plurality of small hole diameters are used, when the contents are powder or small particles, there is an effect of preventing them from entering the valve. In order to prevent the powder from entering between the base film and the valve film and impairing the valve function, there is a method in which the nonwoven fabric 9 is welded so as to cover the air holes to act as a filter.

  The valve film 8 releases excess air that raises the pressure inside the bag from the gap with the flat part, and after release, it works again to prevent intrusion of outside air. A film having a thickness of 25 to 100 μm such as polyester, polypropylene, polystyrene, or polycarbonate is used. The valve film 8 whose outer periphery is punched in conformity with the shape of the concave portion is laminated on a flat portion coated with a non-volatile liquid 7 in order to have a valve function. The liquid 7 having a sealing function is preferably non-volatile in order to avoid changes over time, and silicone oil is preferably used. However, other oils and alcohols having a boiling point higher than 70 ° C., which is a temperature assumed during distribution, are used. Can also be used. Select one that does not volatilize during distribution, has excellent sealing properties that allow the valve film to adhere to the base film, can easily float when air is released, and that does not adversely affect the contents of the bag. When it is necessary to prevent the valve film from falling off, as in the case of sticking to the outside of the package, cover the recess with a plastic film with perforations for releasing air to the outside and weld it to the upper surface of the upper flange. The protective cover 12 is used. Since the valve film adheres to the flat part of the bottom surface of the recess due to the surface tension of the sealing liquid, it is rare that the valve film will drop off naturally. Can do. In this case, the presence or absence of the valve film may be confirmed visually or with a detector such as a photoelectric tube immediately before the filling and packaging machine is attached. Further, when a colored valve film is used, it is possible to easily detect the dropout of the valve. Similarly, if a liquid having sealing properties is colored, the presence or absence of the liquid can be easily confirmed.

The process and material flow will be described with reference to FIG.
First, the recesses 2 are continuously formed on the plastic sheet 1 at regular intervals. Vacuum forming or press forming for forming a film between male and female molds is suitable as a forming method. As the molding die, one processed so that the flange portion 10 can be formed on the outer periphery, and the outer peripheral liquid reservoir 6, the flat portion 5, and the inner peripheral liquid reservoir 4 can be formed on the bottom surface of the recess, respectively. Next, an air hole 3 is drilled in the center of the recess (a). When there is a possibility that the contents are clogged with powder, the non-woven fabric 9 punched on the outer surface of the bottom of the recess is welded so as to cover the air holes. Next, a liquid 7 having a sealing function is applied on the flat portion 5 on the bottom surface of the concave portion, and then a valve film 8 punched in accordance with the inner shape of the concave portion is laminated (b). Next, if necessary, the recess is covered with a plastic film having perforations for preventing the valve film from falling off, and is welded to the upper surface of the flange portion to form the protective cover 12 (c). The plastic sheet obtained by these steps, in which a flat portion having a liquid reservoir on the outer periphery and inner periphery and a concave portion in which a valve film is laminated via a liquid having a sealing property, is continuously formed. The outer periphery is punched out (d) and welded to the package with a filling and packaging machine. In the case of supplying in a continuous tape form, the punching depth is partially adjusted to be shallow so that a part remains without being cut off, thereby forming the continuous portion 16. In the filling and packaging machine, the continuous portion 16 of the valve to be supplied in the form of a tape is cut off, supplied to a predetermined position of the package provided with air holes in advance, and welded to the package by heat applied to the flange portion or ultrasonic waves. The outer periphery of the flange can be punched with a filling and packaging machine, but it is easier to separate the gas venting valve with the filling and packaging machine if most of it is punched just before winding it into a tape. . When the degassing valve is completely punched, it is aligned using a parts feeder, supplied to a predetermined position of the filling and packaging machine, and welded to the package.
Excessive gas in the package that has entered the air holes in the recesses is lifted by the surface tension between the flat part and the valve film that are in close contact with each other via the sealing liquid when the pressure exceeds the open pressure, and flows out from the gap. The air is discharged to the outside through the air holes of the package.

In the case of the degassing valve used by sticking to the outer surface of the package illustrated in FIG. 2, the shape of the outer peripheral flange is different from the case of applying to the inner surface of the package illustrated in FIG. There is. That is, after forming a valve by laminating a valve film on a flat portion on the bottom surface of the recess through a liquid having sealing properties, the recess is covered with a plastic film having perforations and welded to the upper surface of the flange portion. In the case of a valve for sticking to the outer surface, the valve film is exposed to the outside of the package and is used as a cover 12 for protection thereof. Furthermore, in order to expand the sticking area, the outer periphery of the flange is made larger than in the case of sticking on the inner surface, and a lower flange portion 11 having a bottom surface extending to the same position as the bottom surface of the recess is provided. The plastic sheet with the valve is welded at the position of the lower flange portion 11 to the adhesive sheet in which the adhesive 14 is applied to the plastic film substrate 13 and the release liner 15 is laminated after the protective cover is welded to the upper surface of the upper flange portion. Then, an adhesive layer is formed on the bottom surface. The adhesive sheet is previously punched at a position corresponding to the air hole 3 on the bottom surface of the recess. After forming the adhesive layer, the plastic sheet on which the valve is formed half-cuts the outer periphery of the lower flange portion, and a continuous valve label is obtained by a release liner. When using a baseless material in which an adhesive is simply laminated on a release liner as the adhesive sheet, a plastic sheet on which a valve is formed is directly laminated on the adhesive surface and half-cut. The valve label obtained in this manner is supplied to the filling and packaging machine and stuck to a position covering the air holes provided in the package.
Excessive gas that has entered the air hole of the recess through the air hole of the package will lift the valve film against the surface tension between the flat part and the valve film that are in close contact with each other through the sealing liquid when the pressure exceeds the open pressure. Then, it flows out of the gap and is discharged to the outside through the perforations of the plastic film covering the recess.

Using a polypropylene sheet having a thickness of 0.4 mm, circular recesses having a diameter of 18 mm and a depth of 2 mm were continuously formed at a pitch of 25 mm by vacuum forming. At the bottom of the concave portion, the bottom surface is made shallow so that the depth of the portion of 14 to 8 mm from the center is 1 mm, and a liquid pool is provided on the flat portion and its outer periphery, and 6 to 4 mm from the center corresponding to the inner periphery of the flat portion. The portion was set to a depth of 1 mm, and a liquid reservoir was provided on the inner periphery of the flat portion. In the center, four holes were drilled using a 0.5 mm diameter needle to form air holes. Next, silicone oil was applied on the flat portion, and a 50 μm polyester valve film punched to a diameter of 17 mm was laminated thereon. The amount of the silicone oil was adjusted so that when the valve film was laminated, the oil covered the entire surface of the flat portion and did not flow out beyond the liquid reservoir. Subsequently, a flange portion having a width of 2 mm was provided on the outer periphery of the concave portion and punched to a diameter of 22 mm. However, a part of the punching depth was adjusted to be shallow so that it was not partly separated and continued to be taped. Winded up. The venting valve configured as described above was supplied to the filling and packaging machine, the remaining part of the continuous portion was cut off, aligned with the air holes of the packaging bag, and heat-welded to the inner surface of the bag.
When a bag sealed with air is inflated and sealed in a packaging bag with a degassing valve welded to the inner surface, the valve film lifts up on the flat part that is in close contact with oil. It was confirmed that the air in the bag was discharged from the generated gap, and after discharge, the valve film was brought into close contact again and had a valve function. The weight per 100 of these venting valves was a little less than 20 g, and the amount of material used could be greatly reduced compared to 80 g or more of commercially available injection molded valves.

Using a polypropylene sheet having a thickness of 0.4 mm, circular recesses having a diameter of 18 mm and a depth of 1 mm were continuously formed at a pitch of 27 mm by vacuum forming in the same manner as in Example 1. At the bottom of the recess, the bottom surface was shallow so that the depths of 14 to 8 mm and 6 to 4 mm from the center were 0.5 mm, and liquid pools were provided on the flat part and its outer and inner circumferences. The upper flange portion on the outer periphery of the concave portion had a width of 1 mm, and a lower flange portion having a width of 2 mm was formed on the outer periphery thereof on the same surface as the bottom surface of the concave portion. A hole with a diameter of 2 mm was drilled in the center to form an air hole. As in Example 1, after applying silicone oil on the flat part and laminating the valve film, the concave part is covered with a 20 mm diameter plastic film having perforations and welded to the upper surface of the upper flange part for protection. It was. As this plastic film, a perforated film of 12 μ polyester and 30 μ polypropylene was used. Then, after welding the lower flange part of a recessed part outer periphery to the adhesive sheet which uses a 100 micrometer polypropylene as a base material, it half-cut to diameter 24mm and wound up as a valve label. The valve label configured as described above was supplied to the filling and packaging machine, aligned with the air holes of the packaging bag, and attached to the outer surface of the bag.
When a bag sealed with air is inflated and sealed in a packaging bag with a gas vent valve welded to the outer surface and pressed with both hands, the valve film on the flat part that is in close contact with the oil rises. It was confirmed that the air in the bag was discharged from the generated gap, and after discharge, the valve film was brought into close contact again and had a valve function. The weight per 100 of these venting valves was a little less than 30 g, and the amount of material used could be greatly reduced compared to 80 g or more of commercially available injection molded valves. Since oil was previously applied to the valve label, there was no trouble in applying the oil in the filling and packaging process, and the stickiness was not impaired by the oil bleeding.

It is the top view explaining the structure of the valve for gas venting by this invention, and its sectional drawing. It is sectional drawing explaining the structure of the valve of this invention in the case of sticking and using on the outer surface of a package body. The example of the schematic diagram explaining the flow of the process of this invention method is shown. In (a), air holes are provided in the sheet formed with the recesses, in (b) the punched valve film is laminated with a liquid having a sealing function, and in (c), the recesses are covered with the perforated film and the flange portion is formed. The state which welds to an upper surface is shown, (d) is the valve for degassing cut | disconnected within the filling packaging machine.

Explanation of symbols

1 Plastic sheet
DESCRIPTION OF SYMBOLS 2 Recessed part 3 Air hole provided in the recessed part 4 Inner peripheral liquid reservoir 5 Flat part 6 Perimeter peripheral liquid reservoir 7 Liquid having a sealing function 8 Valve film 9 Non-woven fabric 10 Upper flange part 11 Lower flange part 12 Protective cover 13 Adhesive sheet base material 14 Adhesive 15 Release liner 16 Continuous location

Claims (2)

  A flat part having a liquid pool on both the outer and inner circumferences and air holes are provided on the bottom surface of the recess formed in the plastic sheet, and a liquid having a sealing function is applied onto the flat part, and the valve film is flattened from above. A gas venting valve, which is laminated so as to cover the part and the air hole, and is formed so that it can be fixed to the package body at the flange part on the outer periphery of the concave part.   A step of continuously forming a concave portion having a flat portion having a liquid reservoir on both the outer periphery and the inner periphery on the bottom surface in a plastic sheet, a step of punching air holes, and a liquid portion having a sealing function. A step for applying the upper portion, a step for laminating a valve film punched in accordance with the shape of the recess so as to cover the flat portion and the air hole to which the liquid is applied, and a flange for fixing the outer periphery of the recess to the package A method for producing a venting valve, comprising a step of punching out a part.