JPS62233232A - Manufacture of permeable packaging material - Google Patents

Abstract

PURPOSE:To manufacture a packaging material which is superior in water resistance and easy in adjusting permeability, by a method wherein a large number of small holes is formed on a laminated material obtained by welding an outside film and permeable inside sheet thermally to each other through a heat seal layer and then thermocompression bonding of a heat sealing film with which a large number of small holes which is larger than an opening rate of the outside film is provided is applied to the inside sheet. CONSTITUTION:As a heat seal film having permeability, the same material as a heat seal layer 2 is used. Then a laminated material A is formed by welding thermally an outside film 1 composed of a plastic film and a permeable inside sheet 3 to each other through the heat seal layer 2. A large number of small holes 6 is formed on the three-layer laminated material A. Then the heat seal film 4 is laminated on the permeable inside seal sheet 3 surface and formed into the film 4. A small hole 5 is preset so that an opening rate of the same becomes larger than that of the outside film 1 even if the same is deformed thermally at the time of a laminating process. With this construction, permeability of a packaging material is controlled by the opening rate of the outside film 1 and stabilized opening degree is secured.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application] The present invention relates to a method for producing a breathable packaging material used for packaging oxygen absorbers, freshness-preserving agents, and other drugs.

[Conventional technology]

Breathable packaging materials are used to package various drugs such as desiccants, insect repellents, oxygen scavengers, and freshness preservation agents, but if the drug to be packaged is used in the food field, breathable packaging materials are used. In addition to breathability, water resistance, breakage resistance, safety and hygiene, etc. have become important requirements.

For example, as a packaging material for oxygen absorbers, a laminate of paper and perforated polyethylene film has conventionally been used, and the air permeability in this case has been adjusted by the porosity of the polyethylene film. However, when an oxygen absorber packaged with this packaging material is applied to foods with a high moisture content, the packaging material has poor water resistance, so the packaging bag for the oxygen absorber may become damp and damaged, or the perforated polyethylene packaging bag may be damaged. Oxygen absorbers and the like may seep out through the pores, which is unfavorable in terms of food safety and hygiene, and furthermore, the rate of oxygen absorption may slow down due to water wetting.

Furthermore, in adjusting the air permeability, there were drawbacks such as the air holes being deformed during thermal bonding during the production of the packaging material, making the air permeability unstable and causing variations in the oxygen absorption rate.

JP-A-53-51096 and JP-A-53-50065
discloses a packaging material in which two plastic films with different melting points (perforated) are stacked together or laminated and bonded with paper sandwiched between them.

In these cases, since the surface is a plastic film, the water resistance is improved compared to paper, but since there is an adhesive layer such as polyethylene between the perforated film and the paper, air permeability is actually inhibited. It is extremely difficult to control air permeability by changing the number of holes.

In addition, as a packaging material similar to this, a plastic film is laminated with an adhesive layer such as a polyethylene film, then perforated, a heat-sealable perforated film is prepared, and paper is placed between the two. Those integrated by heat welding are already commonly used as packaging materials for oxygen absorbers.

However, when this packaging material is thermally welded, the hole may be deformed by the heat, gas deposits generated during drilling, or convex parts around the hole may partially block the hole due to the heat during thermal welding. Controlling air permeability is extremely difficult, and it is virtually impossible to ensure constant air permeability.

In JP-A-56-124440, two sets of sheets made of laminated plastic film and paper with perforated holes were prepared.
A packaging material is disclosed in which two paper surfaces are integrated via an adhesive layer.

However, this packaging material also has drawbacks such as the presence of an adhesive layer such as ethylene/vinyl acetate copolymer in the middle, which impairs air permeability, and it is extremely difficult to adjust air permeability through openings.

Furthermore, JP-A-56-12.144j discloses a sheet in which plastic film filter paper is laminated with perforated holes, and a sheet in which a plastic film and paper having an oxygen permeability of 300C1+//i・24Hratm or more are laminated. Prepare,
A packaging material is disclosed in which two paper surfaces are integrated via an adhesive layer.

However, this packaging material has a film layer made of non-porous polyethylene and an adhesive layer made of two-handed polyvinyl acetate copolymer, which hinders air permeability and makes it extremely difficult to adjust air permeability. .

In any case, it has been extremely difficult with conventional techniques to control air permeability well through openings.

[Problem that the invention seeks to solve]

It is an object of the present invention to overcome the drawbacks of the above-mentioned conventional techniques and to provide a method for manufacturing a packaging material that has excellent water resistance and allows easy control of air permeability.

[Means for solving problems]

That is, the present invention involves a method of heat-sealing an outer film made of a plastic film to an air-permeable inner sheet through a heat-sealing layer to form a laminate; forming a large number of small holes reaching at least the inner sheet; thermo-compression bonding a heat-sealing film provided with a large number of small holes with an aperture ratio larger than that of the outer film to the inner sheet side of the laminate; The present invention provides a method for producing a breathable packaging material, comprising the steps of:

The present invention further includes the step of heat-sealing an outer film made of a plastic film to an air-permeable inner sheet through a heat-sealing layer to form a laminate; forming a large number of small holes in the circumferential body from the outer film side to at least the inner sheet; laminating and heat-sealing a heat sealing film on the inner sheet side of the laminate; heat sealing. A large number of small holes are formed so as to at least penetrate the second heat sealing film from the side of the heat sealing film, have a depth that does not penetrate the inner sheet, and have an aperture ratio greater than that of the outer film. The present invention provides a method for producing a breathable packaging material, comprising the steps of:

In the present invention, the outer film made of a plastic film preferably has a high strength from the viewpoint of manufacturing or use of the package, and for example, films of polyethylene terephthalate, polyamide, polypropylene, polycarbonate, cellophane, etc. are used.

Among these, polyethylene terephthalate film or polyamide film is preferred in consideration of strength, ease of handling during manufacture, and the like.

The thickness of the outer film is preferably 50 microns or less, most preferably 10 to 20 microns, from the viewpoint of ease of handling during production.

In addition, there are no particular restrictions on the breathability of this outer film, but
Oxygen permeability j OOOCI:, /rim 24Hr・a
tm or less, especially 500cc/IF/・24H
``・ATM or less film is generally used.

When printing on the outer film, printing on the back side prevents the printing ink from coming into direct contact with the food, making it sanitary and safe.

Furthermore, it is also possible to apply peta printing on top of letter printing, and even if the contents ooze out onto the breathable inner sheet, there will be solid printing, that is, concealment printing, so the package will not be damaged. It does not spoil the appearance.

The heat-sealing layer is used to bond the outer film and the breathable inner sheet when manufacturing the package, and examples of the heat-sealing layer include polyethylene, polyethylene-vinyl acetate copolymer, ionomer resin, polybutadiene,
Alternatively, a plastic film such as vinyl chloride or a heat sealant is used.

As the heat sealing agent in this case, for example, a conventional hot melt agent, hot melt emulsion, ionomer latex, ionomer emulsion, polyethylene emulsion or ethylene vinyl acetate emulsion can be used.

If the heat sealing layer is a plastic film, the film thickness is generally 10-70 microns, preferably 15-40 microns.

Additionally, the amount of heat sealant applied is generally 0°59/lr.
l~509/rl, preferably 5g/d~20f
l, ll.

The heat-sealing layer is used by being laminated or coated in close contact with an outer film made of a non-porous, non-porous plastic film. The heat sealing layer is not limited to one layer, but two sealing layers may be used depending on the adhesion between the outer film and the breathable inner sheet 6 during bag making.

In the present invention, a breathable internal sheet is used.

Paper or non-woven fabric is used. In this case, the paper used can be Japanese paper, rayon mixed Japanese paper, Western paper, etc.
Is possible.

Also, the paper used has a basis weight of 15 to 100 g/rII.
are commonly used.

Any nonwoven fabric such as wet type, dry type or spunbond type nonwoven fabric can be used as the nonwoven fabric, and various materials such as polyamide, polyethylene terephthalate, and rayon can be used.

Note that in order to impart water repellency or oil repellency to these papers or nonwoven fabrics, it is possible to use paper or nonwoven fabrics coated with a water repellent or oil repellent.

In the present invention, the air-permeable heat-sealing film used is made of polyethylene, polyethylene-vinyl acetate copolymer, ionomer, polybutadiene, vinyl chloride, or the like, similar to the heat-sealing layer.

According to the method of the present invention, first, as shown in FIG. 1, an outer film 1 and a breathable inner sheet 6 are heat-sealed to each other via a heat-sealing layer 2 to form a laminated film. As for this lamination method, these three materials may be laminated and then thermo-compressed, or the heat-sealing layer 2 may be poured in a hot molten state between the outer film 1 and the breathable inner sheet 3, and then laminated by applying the heat-sealing layer 2 with a cooling roll. An extrusion method may also be used. Alternatively, after laminating the outer film 1 and the heat sealing layer 2 in advance, the breathable inner sheet 3 may be laminated and thermocompressed.

The thus obtained three-layer laminated film is perforated from the outer film 1 side with a needle to form a large number of small holes 6. The needles in this case may be dowels or hot needles, and the size of the holes, size and number of holes per unit area are appropriately selected depending on the desired air permeability. The size of the small hole 6 is usually set so that its major axis is 0.
The selection is made within the range of 1 to 3 dragons, and the aperture ratio is selected within the range of 304 or less.

Note that the depth of the opening formed in this laminated layer must be at least such that it reaches from the surface of the outer film 1 to the inside of the breathable inner sheet 3.

Moreover, when considering the ease of this perforation process, it is preferable to perforate the laminate so as to completely penetrate it.

Next, a heat-sealing film 4 is laminated on the air-permeable inner sheet 3 of this laminate A. In this case, the heat-sealing film 4 is pre-perforated to form small holes 5. It may be heat-sealed, or it may be laminated to the breathable inner sheet 3 of the laminated sheet by any method and then perforated. If this latter method is adopted, it is desirable that the depth be at least as deep as not penetrating the air-permeable inner sheet 3. Note that the position of the small hole 5 is the same as the small hole 6.
It is preferable to provide it in a position that does not directly communicate with the The size of the small hole formed in this heat sealing film 4 is, if the hole is oval in shape, the major axis is usually 0.02fl~
It is desirable that the porosity is in the range of 5 to 30, and that the porosity is substantially larger than that of the outer film 1 even when thermal deformation occurs during lamination. It is desirable to set it to . For example, the aperture ratio of the heat sealing film 4 is set to be 1.5 or more of the aperture ratio of the outer film 1. Therefore, the air permeability of the air permeable packaging material of the present invention is controlled by the aperture ratio of the outer film 1.

Any method such as heat lamination, extrusion lamination, dry lamination, wet lamination, etc. can be used to laminate the non-porous heat sealing film 4 on the 3 sides of the breathable interior sheet of the laminated material.

The air-permeable packaging material 7 obtained in this manner is made into a package by heat-sealing the peripheral edge of the heat-sealing film 4 inside the packaged contents 8 such as an oxygen absorber, as shown in FIG. is formed.

The air-permeable packaging body using the packaging material according to the present invention is used for various types of enclosures such as oxygen absorbers, desiccants, insect repellents, and alcohol-based freshness-preserving agents.

In particular, it is important to control the air permeability of oxygen absorbers, and the method of the present invention makes it possible to produce packaging materials suitable for oxygen absorbers.

When the breathable packaging material obtained by the method of the present invention is used as an oxygen scavenger, the oxygen scavengers include sulfites, bisulfites, dithionites, hydroquinone, catechol, resorcinol, pyrogallol, gallic acid, Oxygen absorbers containing Rongalite, ascorbic acid and/or its salts, isoascorbic acid and/or its salts, sorbose, glucose, lignin, dibutylhydroxytoluene, butylhydroxyanisole, or metal powders such as ferrous salts or iron powders. Further, a carbon dioxide gas generating type oxygen absorber or a carbon dioxide gas absorbing type oxygen absorber or the like is used.

[Operations and Effects] According to the method of the present invention as described above, there is no fear that the openings formed in the outer film for controlling air permeability will be deformed or clogged, and a stable degree of opening can be ensured. be.

Furthermore, since the breathable packaging material obtained by the present invention does not have a non-porous seal layer or a non-porous adhesive layer, its breathability is not inhibited, and it can be easily changed by changing the porosity of the laminate. It is possible to control breathability.

Furthermore, in the case of the method of the present invention, a large number of extremely small holes can be made in the outer material, so that the resulting packaging material has very good water resistance.

〔Example〕

The present invention will be explained in more detail with reference to Examples below.

Example 1 A laminated film made by extruding and laminating 15 micron thick polyethylene (heat sealing layer 2) on a 12 micron thick polyethylene terephthalate film (outer film 1) with text printing and 61 colors of white solid printing on the back side, Holes with hole diameters of 0 and 2 fi were drilled in a sheet C laminated with Japanese paper (breathable inner sheet 3) with a basis weight of 5017/I, distributed at 5-hole intervals in the vertical and horizontal directions (opening ratio 0° 12%).
.

After laminating 30 micron polyethylene (heat-sealing film 4) on this, small holes with a hole diameter of a and 2 ms were bored in the heat-sealing film 4 with a needle at intervals of 2.5fi vertically and 1°5iIIIl horizontally. Breathability (opening ratio 0.83
%), the width of the heat sealing film 4 is 10
A laminated packaging material of 01111 was prepared. The small hole in the heat-sealing film 4 was formed by adjusting the length of the probe so that it could not penetrate the upper surface of the inner sheet 3.

This packaging material is led to a three-sided seal automatic filling packaging machine, and while filling the inside of the heat-sealing film 4 with 1.5 g of iron-based oxygen scavenger, it is sealed from the outside of the outer film 1 with a bar heater, and then cut. An oxygen absorber package with dimensions of 50×50fi was obtained.

As a comparative example, pure white paper (basis weight 50fI/j) and height 2.51
11B spacing, horizontal 1.51111 spacing, hole diameter 0, 211
Iron-based oxygen absorber 1.5. ji
A 50 x 501 EIL oxygen absorber package was obtained.

Place these oxygen absorbing packages on a water-containing line made by soaking 2 g of absorbent cotton with 10 ml of water, and place them in KOP/PR with 500 cc of air.
It was sealed in a bag and stored in a constant temperature bath at 35°C.

The oxygen concentration after 2 days was analyzed, and the condition of the oxygen scavenger on the 14th day was observed. The results are shown in Table 1.

Table 1 Example 2 A polyamide film with a thickness of 15 microns (outer film 1) with text printing and 61 colors of white solid printing on the back, and a pure white roll paper with a basis weight of 409/' and an oil-resistant finish (breathable 15 micron polyethylene (
A laminated sheet 2) was obtained by laminating the heat sealing layer 2).

This sheet has pore diameters of 0.111 and various porosity ratios as shown below.
After drilling the through holes 1, laminate 30 micron polyethylene (thermal sealing film 4) on this paper surface, and then pierce the film 4 with a needle at 2.5 mm intervals, 1.51 mm.
Small holes with a hole diameter of 0.2 mm were bored at a pitch of 11 to obtain a breathable packaging material provided with a heat-sealing film 4 having breathability.

Note that this small hole was formed so as not to penetrate through the breathable inner sheet 3. The breathable packaging material slit to a width of 1001 m is guided to a three-sided seal automatic filling packaging machine, and while filling 3 g of iron-based oxygen absorber into the inside of the heat sealing film 4, it is heated from the outside of the outer film 1 using a bar heater. It was sealed and cut to obtain an oxygen scavenger package with dimensions of 50 x 5 Qgl.

These oxygen absorber packages are packed in KOP/
It was sealed in a PE bag and left in a constant temperature bath at 25°C, and the oxygen concentration was measured over time to examine the relationship between the number of small holes on the outer material side and oxygen absorption.

The survey results are shown in Table 2 and Figure 3.

As described above, it was confirmed that the oxygen absorption rate of the oxygen absorber package was controlled by the porosity of the outer film side.

Example 3 A 12 micron thick polyethylene terephthalate film [outer film 1] with character printing, white solid printing and yellow solid printing on the back side (!: 20 micron polyethylene film [heat sealing layer 2] and tsubo 4135 g/ r
RL polyethylene terephthalate nonwoven fabric [inner sheet 3] heat-laminated laminate (holes with a hole diameter of 0.2 mm were bored in the sword at intervals of 5 in the vertical and horizontal directions (opening ratio o, 12
%).

Holes with a hole diameter of 0.2 fins were drilled in this at an interval of 2 fins vertically and horizontally (
A laminated packaging material with a width of 100 mm was prepared by thermally laminating a polyethylene vinyl acetate copolymer (heat sealing film 4) with an open area ratio of 0.784) of 40 microns.

Note that this small hole was formed so as not to penetrate through the breathable inner sheet 3.

This packaging material is led to a three-sided seal automatic filling packaging machine, and while filling 1.5 g of iron-based oxygen absorber into the inside of the heat-sealing film 4, it is sealed from the outside of the outer film 1 with a bar heater, and then cut. An oxygen absorber package with dimensions of 50 x 50 mm was obtained.

KO this oxygen absorber package with soO,@'s castella
It was sealed in an N/Pg film bag and left at 25°C.

After 2 days, the oxygen concentration in the KON/PE film bag became 0%, and even after being left for one month, the castella cake did not develop mold and its quality was well maintained. It was confirmed that there was no bleeding on the exterior of the oxygen absorber package.

As a comparative example, when only castella cake was left sealed in a KON/PE film bag, mold grew on the surface of the castella cake after one week.

Example 4 In Example 1, the pore diameter of the heat sealing film 4 was set to 0.2.
0 instead of m, 1m11. O,! 1m and 0.
Three types of air-permeable packaging materials were prepared, and experiments similar to those in Example 1 were conducted. The results are shown in Table 3.

Table 3 As shown in Table 3, the oxygen scavenger was in good condition in all cases.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a breathable packaging material obtained by the method of the present invention, and FIG. 2 is a sectional view showing an example of a breathable packaging body formed using the packaging material of FIG. 1. 1 Outer film 2 Heat-sealing layer 3 Breathable inner sheet 4 Heat-sealing film 5 Small holes 6 Small holes 7 Breathability 8 Inclusion Figure 3 is a line showing the relationship between the porosity of the outer film layer and the deoxidation time. It is a diagram. Patent applicant Mitsubishi Gas Chemical Co., Ltd. Agent Patent attorney Sadafumi Kobori

Claims (2)

[Claims] (1) Outer film made of plastic film,
forming a laminate by mutually heat-sealing the air-permeable inner sheet through a heat-sealing layer; forming a large number of small holes in the laminate that reach at least the inner sheet from the outer film side; and a step of thermo-compression bonding a heat-sealing film provided with a large number of small holes with an aperture ratio larger than that of the outer film to the inner sheet side of the laminate. A method for producing a breathable packaging material. (2) forming a laminate by heat-sealing an outer film made of a plastic film with an air-permeable inner sheet through a heat-sealing layer; forming a large number of small holes reaching the sheet; laminating a heat-sealing film on the inner sheet side of the laminate; at least penetrating the heat-sealing film from the heat-sealing film side; a step of forming a large number of small holes with a depth that does not penetrate the inner sheet and with an aperture ratio greater than that of the outer film; and a breathable packaging material characterized by comprising: manufacturing method.