KR20020068468A - Preparation Method of Film for Vacuum Package Having Air Channels - Google Patents

Abstract

PURPOSE: A method for manufacturing a vacuum package film with channels is provided to simplify the process thereof and to reduce a cost of manufacture by forming the channels without a separate embossing process, and to adjust the shape of the channel and a distance between the channels. CONSTITUTION: The method for manufacturing a vacuum package film(40) with channels comprises a step for forming a heat sealing resin layer on an air impermeable substrate(10) by supplying the air impermeable substrate and the heat sealing resin to a laminating unit comprised of a laminating roll and a cooling roll(20). By virtue of plural grooves(21) formed according to a predetermined pattern along the circumference of the cooling roll, the heat sealing resin is formed with the plural air discharge channels defined by plural projections corresponding to the grooves of the cooling roll. The boundary of the channels are defined according to a distance between the projection.

Description

Preparation method of film for vacuum packaging having flow channel {Preparation Method of Film for Vacuum Package Having Air Channels}

The present invention relates to a method for producing a film for vacuum packaging. More specifically, the present invention provides a method for manufacturing a vacuum packaging film made of a heat sealable resin layer having an air discharge passage having a pattern determined by a groove of a cooling roll on a base layer of an air impermeable material, and the same. It relates to a vacuum packaging bag manufactured using.

In the United States and other countries, foods containing meat or processed meat products that require long-term storage are stored in a plastic bag that can be vacuumed to prevent air deterioration. Vacuum treatment using the method and sealing the inlet has been widely used.

The general structure of a bag used for such vacuum packaging is shown in FIG. According to the figure, the bag is a bag body 110, both sides are composed of a plastic film (111, 112); A sealing portion 120 in which left and right ends and bottom ends of the bag main body 110 are heat-sealed to form an inner space for storing contents to be stored; And an opening part 130 formed at an upper end of the bag body 110 to discharge the air inside the bag after the contents are introduced. In this case, the bag main body 110 may be melted by heat like polyethylene, and has a material of a thermoplastic resin that is harmless to a human body.

Therefore, after putting the food to be stored through the opening portion 130 of the bag and then evacuating the air inside the bag by using an air pump or other vacuum device and vacuum-sealed by applying heat above a certain temperature to the opening to seal This becomes possible.

However, in the case of the vacuum packaging bag of this type, the air in the vicinity of the vacuum apparatus is temporarily discharged while the bag body 110 is temporarily discharged in the process of putting the contents and extracting the air filled therein using the vacuum apparatus. Vinyls 111 and 112 on both sides of the constituent are brought into close contact with each other, and thus there is a problem in that air existing on the lower side of the bag is not discharged and remains.

In order to overcome the above problems, a technique has been developed to form a flow path through which an air can flow by embossing a sheet manufactured according to a general manufacturing method. This technique forms a flow path on one or both sides of the film constituting the bag body, and the air present in the lower part of the bag by being sucked along the flow path in the process of sucking the air filled inside the bag using a vacuum device It uses the principle of easy suction and discharge.

US Pat. No. 2,778,173 discloses a rudimentary form using this principle. The patent includes a first sheet portion having an air discharge opening and a second sheet portion overlapping with the first sheet portion, wherein the plurality of protrusions are disposed in at least one of the sheet portions. Is disclosed to form an airtight wrapping paper which forms a passage for airflow connected to the opening, and is described as being capable of forming a protrusion having a pyramid shape, a hemispherical shape, and the like. In the case of the above patent, a heated male and female die or a tool is used to deform the shape of the film itself constituting the sheet to form a protrusion or insert a strip having a protrusion between the first sheet portion and the second sheet portion of the plane. To form. However, the sealing method disclosed in the patent is a step of first sealing the left and right ends and the lower end except for the opening after overlapping the film forming the protrusion; Inserting contents into it and sealing the opening; And through the opening connected to the flow path formed by the protrusion to inhale and discharge the air, and then closing the opening after the discharge of the air is completed. It has many disadvantages such as having to go through.

Therefore, while having the structure of the general vacuum packaging bag as shown in FIG. 1, the technique which comprises the main body of a bag by laminated | multilayer film and embossing at least one of the said both surfaces by the embossing metal mold | die is known.

Figure 2 is a perspective view schematically showing the structure of a conventional vacuum packaging bag, one of which is embossed on both sides. The vacuum packaging bag in which the flow path is formed as shown in FIG. 1 is embossed on one layer 113 of double-sided laminated film layers 113 and 114 constituting the bag main body 110 of the conventional vacuum packaging bag shown in FIG. By processing to form a flow path 115 between the protrusion 116 and the protrusion is configured to facilitate the intake of air. Such technology is described in US Pat. 34,929. That is, each panel consists of first and second panels overlapping each other, and each panel having a uniform thickness is sealed at left and right ends and lower ends except for an opening to accommodate contents. In addition, each of the first and second panels is composed of a heat sealable inner layer having a uniform thickness and an air impermeable outer layer having a uniform thickness, the interior of at least one of the first and second panels And a plurality of protrusions are formed on the outer surface, having a regular waffle pattern (see FIGS. 6 and 7 of the patent). In the case of the patent, an embossed pattern of female and male form is formed on the hot roller, and the flow path 115 is formed by supplying a laminated film made of an air impermeable sheet and a heat sealable sheet to the hot roller and embossing under heating. ) And protrusions 116. However, when the protrusions and the flow paths are forcibly formed by heat of a film having a constant thickness, the film thickness of the stretched portion becomes thin because the film between the flow paths and the protrusions is stretched. Therefore, the film is torn during the embossing process, or a pinhole is formed in the film due to the re-stretching of the film during the process of adding the contents and applying the vacuum, thereby causing air to communicate with the outside. In addition, the embossing mold has a disadvantage in that the mold is frequently replaced because it damages the film due to abrasion when used for a long time.

On the other hand, a technique having other types of protrusions is disclosed in US Pat. No. 5,554,423 and the corresponding EP 0 648 688 B1. That is, the tube member for manufacturing the vacuum packaging bag of the patent has a first sheet composed of a gas impermeable outer layer and a heat sealable inner layer, and a second sheet composed of a gas impermeable outer layer and a heat sealable inner layer. The upper and lower edges of the are bonded to each other to have a space for accommodating the contents. In particular, a plurality of heat sealable strand members are thermally bonded to the inner layer surface of any one of the first sheet and the second sheet in a direction parallel to the bonding portions of the upper and lower edges, and spaced apart at regular intervals to thereby adjoin the adjacent strands. The space between the members serves as a channel for air discharge. In this regard, a process of arranging and thermally bonding a plurality of heat sealable strand members on a sheet according to the patent is schematically illustrated in FIG. 3. In the case of the above patent, a plurality of heat sealable strand members 4 are arranged at regular intervals from the extrusion head 2 for strand production on the heat sealable layer of the laminated sheet 1 composed of a gas impermeable layer and a heat sealable layer. By means of pressure rollers 3, 3 '. However, separate equipment for producing the strands is required and a complicated and precise process of thermally bonding the plurality of strands on the heat sealable inner layer at regular intervals is required. In addition, it is difficult to form a film having a thinner thickness because only a strand shape is possible to form a flow path, so that various flow path patterns cannot be formed, and after forming a heat sealable inner layer, the strand member for flow path formation must be bonded again. Do.

On the other hand, a method is known in which a flow path is directly formed on a heat sealable inner layer using a co-extrusion method by blowing, and at the same time laminated with an air impermeable outer layer. In this regard, Figure 4 shows a schematic principle of the process.

That is, in the method, a protrusion 5 is formed on the inner coextrusion ring, and a flow path is formed by the protrusion in the process of manufacturing the vacuum packaging film by blowing from the bottom up. However, the above technique also has a limitation in forming various and superior air discharge passages because the flow path in the vacuum packaging film has only a stripe shape regardless of the shape of the projection. In particular, the method has a limitation in reducing the gap between the flow path and the flow path as shown in the characteristic of the blowing method. Therefore, due to the close contact between the sheet surface constituting the bag body during vacuum packaging, there is a problem that the smooth vacuum formation is difficult because the air discharge performance in the bag is reduced.

Therefore, there has been an increasing demand for a method of manufacturing a film for vacuum packaging, which can form various flow path patterns more easily than in the prior art.

Accordingly, the present inventors when laminating while supplying a heat-sealing resin melt-extruded from the air-impermeable base layer and the nozzle portion in order to produce a film for vacuum packaging while feeding between the lamination roll and the cooling roll formed with a groove of a predetermined pattern, It has been found that it is easier to overcome the problems caused in the prior art.

Accordingly, it is an object of the present invention to provide a method for producing a film for vacuum packaging, which can effectively prevent pinhole generation and improve vacuum property by creating an accurate flow path.

Another object of the present invention is to provide a method for manufacturing a film for vacuum packaging that can be provided with a variety of flow path patterns by a simpler method.

Still another object of the present invention is to provide a method for producing a film for vacuum packaging, which has a thin thickness and excellent physical properties compared to the conventional method.

Still another object of the present invention is to provide a vacuum packaging bag manufactured from the laminated film according to the above method.

In order to achieve the above object, a method for manufacturing a vacuum packaging film according to an aspect of the present invention by supplying a substrate of an air impermeable material to a lamination unit consisting of a lamination roll and a cooling roll with a heat-sealing resin to be melt-extruded, And forming a heat sealable resin layer on the substrate of the air impermeable material, wherein the heat-extruded heat sealability is extruded by a plurality of grooves in which a predetermined pattern is formed along the circumferential surface of the cooling roll in the lamination process. The resin is cooled and molded so that an air discharge passage is formed in the heat sealable resin layer, the air discharge passage being bounded by a gap between the plurality of protrusions corresponding to the grooves and the adjacent protrusions.

In addition, the vacuum packaging bag according to another aspect of the present invention is composed of a first sheet and a second sheet overlapping each other, each sheet includes an air impermeable base material layer and a heat sealable resin layer as the inner layer. In the vacuum packaging bag consisting of a laminated film, the lower edges of the first sheet and the second sheet, and the left and right corners are bonded to each other to accommodate the contents, among the first sheet and the second sheet. At least one is characterized in that the film for vacuum packaging produced according to the method.

1 is a perspective view showing a schematic structure of a typical vacuum packaging bag.

Figure 2 is a perspective view schematically showing the structure of a conventional vacuum packaging bag, one of which is embossed on both sides.

FIG. 3 is a diagram showing a prior art for arranging and adhering a plurality of heat sealable strand members on a heat sealable layer of a laminated sheet composed of a gas impermeable layer and a heat sealable layer.

4 is a diagram illustrating a prior art for forming a flow path using a coextrusion method by blowing.

FIG. 5 is a view schematically showing a process for forming a heat-sealing resin layer having protrusions and an air discharge passage on an air impermeable substrate layer according to an embodiment of the present invention.

6 is a view showing in more detail the principle of the process for forming a heat-sealing resin layer having a protrusion and an air discharge passage on the air impermeable substrate layer according to an embodiment of the present invention.

FIG. 7 is a bottom perspective view of the extruder shown in FIG. 5. FIG.

8 is a plan view of a vacuum packaging film according to an embodiment of the present invention.

9 is a plan view of a film for vacuum packaging according to another embodiment of the present invention.

10 is a perspective view schematically showing the structure of a vacuum packaging bag according to an embodiment of the present invention.

* Description of the symbols for the main parts of the drawings *

1: laminated sheet 2: extrusion head for strand production

3, 3 ': pressure roller 4: strand

5: flow path forming groove 10: base material

20: cooling roll 21: groove

20 ': lamination roll 30: extruder

31 nozzle part 32 nozzle

40: film for vacuum packaging 41: protrusion

42: Euro 50: bag for vacuum packaging

51: First Sheet 52: Second Sheet

111, 112: plastic film 110: bag body

120: suture 130: opening

Hereinafter, the present invention may be described in more detail with reference to the accompanying drawings, but the present invention is not limited thereto but is only illustrated to assist in understanding the present invention.

FIG. 5 is a view schematically showing a process for forming a heat-sealing resin layer having protrusions and an air discharge passage on an air impermeable substrate layer according to an embodiment of the present invention.

In the figure, the lamination roll 20 'and the cooling roll 20 constituting the lamination unit are arranged at regular intervals so that the heat-sealing resin extruded on the air impermeable substrate can be laminated while cooling. The material of the lamination roll and the cooling roll is not particularly limited, but a material such as steel or rubber is used. The interval between the lamination roll and the cooling roll is adjusted in consideration of the specifications (thickness and the like) of the film for vacuum packaging. At this time, the cooling roll is preferably maintained at about -15 ~ -10 ℃ so that the resin is melt-extruded on the substrate layer as described later, the temperature of the cooling roll may vary depending on the lamination conditions .

On the other hand, the cooling rolls typically have a larger diameter (for example, about 1.5 to 3 times) than the lamination rolls, but are not necessarily limited thereto.

The air impermeable substrate 10 is supplied between the cooling roll 20 and the lamination roll 20 'under the drive of a supply means (not shown). The material of the base material is polyester, polyamide, EVOH, and the like, and is preferably made of a material that can maintain mechanical properties even when heated together with the thermosetting resin layer in a subsequent air sealing process.

The heat-sealing resin is a thermoplastic resin, in which the contact surface is relatively firm when the inner surface of the facing layer is pressed under heating after putting the contents to be contained in the vacuum packaging bag manufactured using the laminated film of the present invention and vacuuming. It should be glued to prevent penetration between the inside and outside of the bag. In particular, it is preferable to use polyethylene (PE) suitable for storage of food and the like and harmless to the human body.

According to the above embodiment, the extruder 30 is provided to supply the extruded heat-sealing resin between the cooling roll 20 and the lamination roll 20 'to be laminated on the base layer. In this figure, the heat sealable resin is supplied through the nozzle part 31 of the extruder 30. At this time, the sealing resin is extruded from the nozzle unit 31, the temperature varies depending on the type of resin used, but is typically in the range of about 200 ~ 250 ℃, depending on the thickness of the heat sealable resin layer on the base layer laminated unit Extrusion amount supplied to is determined.

In the present invention, the cooling roll 20 is formed with a predetermined pattern of grooves along the circumferential surface. In the embodiment according to FIG. 5, there is shown a vacuum packaging film having a pattern of an exemplary groove which can be applied according to the invention and a heat sealable resin layer formed with corresponding protrusions and flow paths. As such, the present invention utilizes a method in which the heat-sealed resin melt-extruded in the extruder is supplied from the nozzle of the extruder and naturally molded by the grooves of the cooling roll while being cooled. Therefore, the heat-sealing resin melt-extruded together with the substrate is supplied to a lamination unit including a cooling roll and a lamination roll in which grooves are formed in a predetermined pattern, and the heat-sealing resin is cooled and laminated on the substrate to correspond to the grooves. A vacuum packaging film 40 having a heat sealable resin layer in which protrusions and a flow path are formed can be manufactured. Since the pattern of the groove can be variously expressed in a straight line and / or curve according to the shape of the desired flow path, there is no particular limitation on the flow path pattern that can be expressed on the vacuum packaging film. As such, when the melt-extruded heat sealable resin is adopted to be cooled / molded by grooves, unlike the post-embossing treatment method, even if the thickness of the heat sealable resin layer is formed relatively thin, there is no problem in vacuum performance.

The formation principle of the flow path described above is illustrated in more detail in FIG. 6, and in FIG. 7, a bottom perspective view of an extruder in which a heat sealable resin is melt extruded is illustrated. As shown in FIG. 7, the heat sealable resin is extruded and supplied to the lamination unit through the nozzle 32 provided in the nozzle unit 31.

Looking at the manufacturing process of the vacuum packaging film according to the present invention in more detail with reference to FIGS. 5 to 7, first, the substrate 10 is supplied between the cooling roll 20 and the lamination roll 20 ′ in the lamination unit. At this time, the groove 21 of the predetermined pattern is formed on the surface of the cooling roll 20 as described above. In the above embodiment, grooves having a plurality of uneven patterns are formed along the circumference of the cooling roll 20, and are mutually symmetric with the adjacent grooves.

As shown in the figure, the extruder 30 is disposed between the cooling roll 20 and the lamination roll 20 'on which the grooves 21 of a specific pattern are formed, and extruded from the nozzle 32 of the extruder 30. When the heat-sealing resin is pressed together with the substrate 10 by the cooling roll and the laminating roll of the lamination unit, the protrusions of the pattern corresponding to the grooves are formed on the heat-sealing resin layer located on the vacuum packaging film 40. Molded. At this time, an air discharge passage is formed in a portion of the heat sealable resin layer that is not formed as a protrusion by the groove 21 on the cooling roll 20.

In the present invention, for example, the flow path may be formed so that a plurality of stripe patterns extend in the longitudinal direction of the film, but is not necessarily limited thereto, and may be applicable in a vacuuming process of a vacuum bag, such as a lattice pattern. It is sufficient that the flow path pattern can be formed.

In this regard, according to FIGS. 5 and 6, grooves of a plurality of uneven patterns are formed along the circumference on the cooling roll, and accordingly, a gap between the plurality of adjacent protrusions on the heat sealable resin layer is formed. The boundary is defined to function as a movement path of air, and in the present invention, the shape of the flow path can be freely expressed by adjusting the pattern of the groove formed in the cooling roll. On the contrary, a cooling roll in which the uneven pattern protrudes may also be used, and in this case, the pattern of the flow path to be formed has a uneven shape.

8 is a plan view of a film for vacuum packaging manufactured according to the above embodiment, in which a plurality of protrusions of the uneven pattern are formed, and an interval between adjacent protrusions corresponds to a flow path and extends along the length direction of the film. . As such, the vacuum may be discharged up to the air remaining deep inside the packaging bag along the flow path formed as described above.

An alternative embodiment of the vacuum packaging film produced according to the invention is shown in FIG. 9. According to the optional embodiment, a plurality of wave pattern grooves are formed along the circumference of the cooling roll, and thus the flow path that is bounded by the spacing of the formed protrusions also has a plurality of wave patterns.

On the other hand, the thickness of the protrusion formed in the resin layer of the laminated film 40 is determined according to the depth of the groove 21 formed in the cooling roll 20, the width of the flow path is determined according to the interval between the adjacent grooves. . As such, the shape, width, and thickness of the air discharge passage defined by the distance between the adjacent protrusions may be changed by freely adjusting the variable for the groove of the cooling roll according to the use of the laminated film. In particular, the narrower the width of the flow path (the spacing between adjacent protrusions) in the later vacuuming process, the better.

As described above, in the heat sealable resin layer in which the flow path is formed, the thickness of the flow path is, for example, about 40 to 100 µm, the thickness of the protrusion is about 150 to 300 µm, and the thickness of the base layer is about 30 Although it is typical that it is -200 micrometers, it is not necessarily limited to this.

Meanwhile, according to the present invention, the base layer may be composed of one layer or two or more layers, and the multilayer structure of the base layer may be configured within the allowable total thickness of the base layer described above.

The vacuum packaging film manufactured according to the present invention may be used to manufacture a vacuum packaging bag by a conventional method, and one embodiment is illustrated in FIG. 10. As shown in the figure, the vacuum packaging bag 50 is a stack of the first sheet 51 and the second sheet 52 overlap each other, the flow path pattern formed on one of the first sheet and the second sheet It is made of a film, wherein the material of the resin layer and the base layer constituting each sheet is typically the same, but not necessarily. At this time, the heat sealable resin layer forms an inner layer and the base layer forms an outer layer. In addition, the bottom edges of the first sheet and the second sheet, and the left and right edges, which overlap each other to accommodate the contents, are bonded to each other. At this time, in the case of the sheet in which a flow path is not formed, it is typical to have thickness of about 50-150 micrometers, for example. Although the drawing illustrates an example in which a flow path of a predetermined pattern is formed on one of the first sheet and the second sheet, it is also possible to use a film in which the flow path is formed in both the first sheet and the second sheet. In addition, various types of vacuum packaging bags may be manufactured using the laminated film molded with the flow path of the present invention.

The present invention can be more clearly understood by the following examples, which are only intended to illustrate the present invention and are not intended to limit the scope of the invention.

Example 1

As shown in FIG. 5, a substrate layer having a width of 1200 mm and a thickness of 75 μm of polyamide material was supplied to the lamination unit at a speed of 80 m / min. At this time, both the lamination roll and the cooling roll were made of steel, and the diameters were 250Φ and 500Φ, respectively, and the depth of the grooves on the cooling roll was 0.8 mm. The gap between the lamination roll and the cooling roll was maintained at 100 μm, and an extruder was disposed between the lamination roll and the cooling roll to extrude the melted polyethylene resin (trade name CA-110 of SK Corporation) at 220 ° C. from the nozzle of the extruder. To the lamination unit. At this time, the temperature of the cooling roll was maintained at -12 ℃. In the vacuum packaging film manufactured as described above, the substrate layer had a thickness of 75 μm, the protrusion part had a thickness of 250 μm, and the flow path had a thickness of 25 μm. The vacuum packaging film manufactured as described above was used as the first sheet, and a vacuum packaging bag of 300 × 400 mm was prepared using the second sheet made of the same material. At this time, no flow path was formed in the second sheet, the thickness of the substrate layer was 75 μm, and the thickness of the heat sealable resin layer was 25 μm. After the sample was put in the vacuum packaging bag, the vacuum packaging machine (trade name: Foodsaver 550) was used for complete vacuum packaging. After preparing 100 vacuum-packed samples by the above method, the number of samples released after 100 hours was measured, and the results are shown in Table 1 below.

Comparative Example 1

The performance was evaluated in the same manner as in Example 1 except for using the trade name Foodsaver ^® manufactured by Tilia Inc .. The results are shown in Table 1 below.

Comparative Example 2

The performance was evaluated in the same manner as in Example 1 except for using the trade name MAGIC VAC manufactured and sold by Flaemnouva. The results are shown in Table 1 below.

division Example 1 Comparative Example 1 Comparative Example 2 Number of vacuumed samples 0 20 5

As can be seen in Table 1, in the case of Example 1 according to the present invention, the vacuum holding period was much better than that of the conventional vacuum packing bag.

In the method for manufacturing a vacuum packaging film according to the present invention, when forming a protrusion by naturally forming by a groove formed in a cooling roll during the process of laminating a heat sealable resin on an air impermeable substrate, a flow path may be formed without a separate embossing treatment. Since the process can be simplified, and a separate embossing mold is not required, the cost reduction effect is large. In addition, by adjusting the pattern of the groove formed on the cooling roll, it is possible to form a variety of flow path patterns and has the advantage of adjusting the flow path spacing. Therefore, compared to the prior art, the productivity of the vacuum packaging film can be improved by about 50%.

Simple modifications and variations of the present invention can be readily used by those skilled in the art, and all such variations or modifications can be considered to be included within the scope of the present invention.

Claims (8)

Supplying a substrate of an air impermeable material to a lamination unit comprising a lamination roll and a cooling roll together with a heat sealable resin that is melt-extruded to form a heat sealable resin layer on the substrate of the air impermeable material; And a plurality of protrusions corresponding to the grooves in the heat sealable resin layer by cold forming the heat-extruded heat sealable resin by a plurality of grooves formed in a predetermined pattern along the circumferential surface of the cooling roll in the lamination process. A method for manufacturing a vacuum packaging film, characterized in that the air discharge passage is defined by the interval between the adjacent protrusions. The method of claim 1, wherein the air impermeable base layer is made of polyamide, polyester or EVOH. The method for manufacturing a vacuum packaging film according to claim 1, wherein the heat sealable resin layer is made of polyethylene. The method for manufacturing a vacuum packaging film according to claim 1, wherein grooves of a plurality of uneven patterns are formed along the circumference of the cooling roll. The method for manufacturing a vacuum packaging film according to claim 1, wherein grooves of a plurality of wave patterns are formed along the circumference of the cooling roll. The method of manufacturing a vacuum packaging film according to claim 1, wherein grooves of a stripe pattern are formed along the circumference of the cooling roll. The method of manufacturing a vacuum packaging film according to claim 2, wherein the base layer has one layer or two or more multilayer structures. Each sheet is composed of a first sheet and a second sheet overlapping each other, and each sheet is composed of a laminated film including a base layer of an air impermeable material as an outer layer and a heat sealable resin layer as an inner layer, so as to accommodate contents. In the vacuum packaging bag in which the bottom edges of the first sheet and the second sheet, and the left and right edges are bonded to each other, At least one of the first sheet and the second sheet is a vacuum packaging bag, characterized in that the vacuum packaging film produced according to claim 1.