JP2005187062A - Antibacterial film and antibacterial packaging bag - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an antibacterial film and packaging bag that suppress the propagation of bacteria and continuously exhibit the effects in sustaining the quality of the contents. <P>SOLUTION: The antibacterial film is formed such that a barrier layer, a moisture absorbent layer, and an antibacterial layer are bonded together in that order. In addition, at least part of the packaging bag is formed from the antibacterial film so that the antibacterial layer is disposed inside the packaging bag. The thickness of the antibacterial layer 2 is, for instance, 10 to 30 μm, preferably about 15 to 25 μm. The thickness of the moisture absorbent layer is, for example, about 5 to 200 μm, preferably about 10 to 50 μm. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an antibacterial film and a packaging bag using the film. Such a packaging bag is used for maintaining the quality of foods such as cheese and ham, confectionery, and pharmaceuticals.

In recent years, in response to the increasing demand for maintaining the freshness (quality maintenance) of food packaging, as a method of maintaining the quality, a filling technique such as vacuum packaging or gas replacement with CO ₂ in the packaging bag can be used, Techniques such as enclosing a functional material such as a desiccant or an oxygen scavenger in a packaging bag or providing a film having a function similar to that of the functional material in one layer of the packaging bag are performed. According to these methods, in addition to preventing the deterioration of the taste of food, it has the effect of making it difficult to generate bacteria and fungi that cause spoilage, but once opened, for example, there is no deoxygenation effect, and after resealing The antibacterial action of is lost or significantly reduced.

  On the other hand, it is known that by providing a layer in which an antibacterial agent is kneaded in one layer of the packaging bag, an action of sterilizing and preventing proliferation of bacteria and molds generated in the food and in the packaging bag can be obtained ( For example, see Patent Documents 1 to 4). However, in order to improve the sustainability and effect of the sterilization and proliferation preventing action, it is necessary to use other freshness-keeping agents or the like together (for example, see Patent Document 4).

JP-A-6-65011 JP-A-6-72816 JP 2000-63219 A JP 2002-309105 A

It is an object of the present invention to provide an antibacterial film and a packaging bag that do not require a separate desiccant or freshness retaining agent sachet, can suppress the growth of bacteria, and can continuously exert the content retaining effect of the contents. It is in.
Another object of the present invention is to provide an antibacterial film and a packaging bag that can exhibit an excellent antibacterial action even after resealing.

  As a result of intensive studies to achieve the above object, the inventors of the present invention have found that, according to the packaging bag using the laminated film in which the water absorption layer and the antibacterial layer are provided inside the barrier layer, the moisture present in the packaging bag It was found that the microorganisms can be effectively sterilized and proliferated, and the freshness and quality of the contents can be stably maintained over a long period of time, thereby completing the present invention.

  That is, this invention provides the antibacterial film laminated | stacked in order of the barrier layer, the water absorption layer, and the antibacterial layer.

  Moreover, this invention provides the packaging bag in which at least one part is formed with the antimicrobial layer inside by the antimicrobial film of the said invention.

  According to the present invention, since the antibacterial layer is provided on the content side (inner side) of the film, bacteria and mold in the packaging bag can be sterilized and prevented from growing, and further, the water absorbing layer is essential for the growth of bacteria and mold. The moisture in the packaging bag can be absorbed more effectively to prevent the growth of bacteria, and the barrier layer hardly absorbs moisture from the outside and can improve the hygroscopicity from one direction inside. It can be kept stable for a period.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic sectional view showing an example of the antibacterial film of the present invention. In the antibacterial film 1 shown in FIG. 1, an antibacterial layer 2, a water absorption layer 3, and a barrier layer 4 are laminated in this order.

  The antibacterial layer 2 can be composed of an antibacterial agent and a thermoplastic resin. As the antibacterial agent, an inorganic antibacterial agent or an organic antibacterial agent can be used. Examples of the inorganic antibacterial agent include halogen compounds containing chlorine, bromine and iodine; glass containing copper arsenite, cuprous oxide, silver nitrate, silver and copper; crystalline aluminum silicate (zeolite), Examples include amorphous aluminum silicates such as amorphous synthetic aluminum silicate; zirconium phosphate carrying ions such as Ag, Cu, Zn; zinc oxide compounds; magnesium oxide compounds; calcium hydroxide compounds. Examples of the organic antibacterial agent include nitrogen compounds such as amines and triazines; organometallic compounds such as arsenic, copper, mercury, tin, and zinc; organosulfur compounds such as isothiazolone and pyrithione thiocyanate; alkyldimethylbenzylammonium compounds And quaternary ammonium compounds such as chlorinated phenol, bisphenol, O-phenylphenol, and the like. Moreover, antibacterial agents derived from natural products such as hinokitiol, wasaolo, chitin chitosan, etc. can also be used. Among these, inorganic antibacterial agents are preferable from the viewpoint of safety, and zinc oxide compounds and amorphous synthetic aluminum silicate compounds disclosed in Patent Document 3 are particularly preferable from the viewpoint of handleability. . These antibacterial agents can be used alone or in combination of two or more.

  The amount of the antibacterial agent in the antibacterial layer 2 can be appropriately set according to the antibacterial degree of the antibacterial agent, and is, for example, about 1 to 10% by weight, preferably about 2 to 6% by weight.

  As the thermoplastic resin, a resin having moisture permeability (moisture permeable resin) is used in order to secure the water absorbing function in the water absorbing layer 3 outside the antibacterial layer 2. Examples of moisture permeable resins include low density polyethylene (LDPE), linear low density polyethylene (LLDPE), ethylene-propylene copolymer, polybutene-1, ethylene-butene-1 copolymer, ethylene-propylene-butene- Examples thereof include olefin-based resins such as 1 copolymer, polymethylpentene-1, ethylene-vinyl acetate copolymer (EVA), and ionomer. When the antibacterial layer 2 constitutes the innermost layer at the time of forming the packaging bag and is used as a sealant, the antibacterial layer 2 is preferably composed of a resin having heat sealability, and LDPE, LLDPE, EVA, etc. are particularly preferably used. .

The antibacterial layer 2 has moisture permeability that does not hinder the water absorption function of the water absorption layer 3. Specifically, it is preferable that the water vapor permeability of the antibacterial layer 2 is 20 g / m ² · 24 h · atm or more (based on JIS Z 0208) because the water absorption performance of the water absorption layer 3 can be improved. The water vapor permeability can be adjusted by appropriately selecting the type of resin constituting the antibacterial layer 2, the thickness of the layer, etc., or making the layer porous.

  The antibacterial film of the present invention is used for packaging food or the like such that the antibacterial layer 2 is on the inner surface side. When forming the packaging bag, the inner surface of the antibacterial layer 2 may be subjected to a treatment for enhancing antibacterial properties. As the treatment, an embossing treatment for expanding the contact area between the surface of the antibacterial layer 2 and the contents, and a state in which the antibacterial agent in the antibacterial layer 2 is likely to bleed (a state in which the antibacterial agent is exposed on the surface). Examples include corona treatment. The thickness of the antibacterial layer 2 is, for example, about 10 to 30 μm, preferably about 15 to 25 μm. When the thickness of the antibacterial layer 2 is less than 10 μm, sufficient heat seal strength cannot be obtained when the antibacterial layer 2 constitutes the innermost layer of the packaging bag and is used as a sealant. Tends to decrease.

The water absorbing layer 3 can be composed of a water absorbing agent and a thermoplastic resin. The water-absorbing agent is not particularly limited, and examples thereof include known water-absorbing agents, for example, metal sulfates such as magnesium sulfate, cobalt sulfate and copper sulfate, desiccants such as calcium carbonate, silica gel, zeolite and activated alumina. These water absorbing agents are used alone or in combination of a plurality of types. For example, as the film used for forming the pouch bag, a water absorbing agent having a small volume change due to water absorption is preferably used. In addition, when used for food packaging, a water-absorbing agent containing at least magnesium sulfate is preferably used from the viewpoint of safety, water absorption, etc., for example, magnesium sulfate alone, a mixture of magnesium sulfate and silica, etc. are particularly preferable. . Magnesium sulfate is represented by the formula: MgSO ₄ · nH ₂ O (n is an integer of 0 to 3). As magnesium sulfate, anhydrous magnesium sulfate (n = 0) or low water content magnesium sulfate (n = 1 or 2) is preferable.

  Although the particle size of a water absorbing agent is not specifically limited, For example, it is about 1-20 micrometers (preferably 3-10 micrometers). The amount of the water absorbing agent used is, for example, about 5 to 50 parts by weight, preferably about 10 to 40 parts by weight with respect to 100 parts by weight of the thermoplastic resin constituting the water absorbing layer. If the amount of the water-absorbing agent exceeds 50 parts by weight, the dispersibility in the resin is lowered, and the economical efficiency is inferior. If it is less than 5 parts by weight, it is difficult to obtain sufficient water absorption and water retention.

  The thermoplastic resin is not particularly limited, and a wide range of thermoplastic resins can be used. As a typical example, in addition to the moisture-permeable resin exemplified in the antibacterial layer 2, for example, medium density polyethylene, ethylene- (meth) Examples thereof include olefin resins such as acrylate copolymers, polycarbonate, polyamide, polyvinyl chloride, polystyrene, polyester, polyacrylate, and the like. These thermoplastic resins may be used alone or in combination of two or more. What added tackifying resin, such as petroleum resin, to these may be used.

  Among the above thermoplastic resins, a resin having a certain degree of moisture permeability is preferable in order to ensure the water absorption function, and examples thereof include those exemplified as the moisture permeable resin in the antibacterial layer 2. Of these, LDPE, LLDPE, EVA and the like are preferably used, and EVA is particularly preferable because it is suitable for extrusion molding. The thermoplastic resin constituting the water-absorbing layer 3 may be the same as or different from the resin constituting the antibacterial layer 2, but is preferably the same resin in terms of compatibility.

The water vapor permeability of the water absorbing layer 3 is preferably, for example, 20 g / m ² · 24 h · atm or more (based on JIS Z 0208). The water vapor permeability can be adjusted by appropriately selecting the type of resin constituting the water-absorbing layer 3, the thickness of the layer, etc., or making the layer porous. When the antibacterial layer 2 and the water absorption layer 3 are made of the same thermoplastic resin, and the antibacterial layer 2 constitutes the innermost layer of the packaging bag and is used as a sealant, the water vapor permeability of the antibacterial layer 2 is the water absorption layer. Preferably, the water vapor permeability is lower than 3. When the water vapor permeability of the antibacterial layer 2 is too high, there is a disadvantage that the heat seal strength is lowered because the density of the layer is lowered. According to the study by the present inventors, the heat seal strength of the antibacterial layer 2 is significantly reduced even when a large amount of a hygroscopic agent is added to the antibacterial layer 2. On the other hand, according to the antibacterial film 1 of the present invention, since the antibacterial layer 2 and the water absorbing layer 3 are provided as different layers, the antibacterial layer 2 constitutes the innermost layer of the packaging bag, as well as being excellent in hygroscopicity and antibacterial properties. In this case, high heat seal strength can be exhibited.

  The water absorption performance of the water absorption layer 3 is exhibited according to the water vapor transmission rate of the antibacterial layer 2 disposed inside the water absorption layer 3. Specifically, when the water vapor permeability of the antibacterial layer 2 is high, the water absorption layer 3 can exhibit high water absorption performance, so that the humidity inside the packaging bag can be adjusted to a low range. On the other hand, when the water vapor permeability of the antibacterial layer 2 is low, the water absorption performance of the water absorption layer 3 is reduced, so that the humidity inside the packaging bag can be adjusted to a high range. Since the packaging bag of the present invention can adjust the humidity in the packaging bag to a range suitable for maintaining the quality of the contents as described above, it can be used as a bag for packaging various contents.

  The thickness of the water absorbing layer 3 is appropriately selected according to the form of the packaging bag, the type of constituent material of the water absorbing layer, the water absorbing performance, and the like, and is, for example, about 5 to 200 μm, preferably about 10 to 50 μm.

  The barrier layer 4 may be any layer that blocks water vapor, and is preferably a layer that blocks oxygen and light. Examples of layers that block water vapor include metal foils such as aluminum foil; vapor deposition layers such as silica and alumina, vapor deposition film layers obtained by depositing aluminum, silica, alumina, etc. on appropriate films, polyvinylidene chloride coating layers, and high density Polyolefin (HDPE) film layer, polypropylene (PP), olefinic film such as cyclic olefinic polymer, ethylene-vinyl alcohol copolymer (EVOH) film, stretched polyamide (O-Ny) film, polyvinylidene chloride film or these The sheet | seat etc. can be used.

  The barrier layer 4 may be a layer in which a layer that blocks oxygen and light is laminated on the layer that blocks water vapor. Examples of the layer for blocking oxygen include, for example, ethylene-vinyl alcohol copolymer, polyamide resin [for example, polyamide 6, polyamide 6,6, polyamide 6 / 6,6 copolymer, metaxylylene adipamide (MXD6 ), Etc.], films made of an oxygen barrier resin such as polyvinylidene chloride resin, polyvinyl alcohol, the oxygen barrier resin coating layer, a metal foil such as aluminum foil; a vapor deposition layer such as silica or alumina, aluminum, silica or alumina. The vapor deposition film layer etc. which vapor-deposited etc. on the suitable film are mentioned.

  In the case of packaging food, the barrier layer usually has a gas barrier property that does not allow gas (oxygen, ethylene, etc.) that tends to lower the freshness of the food, and a water vapor barrier property that does not allow water vapor to permeate the food. ing. Of these, aluminum foil, a vapor deposition layer, and the like are preferable in terms of light shielding properties. In particular, in the case of the water absorbing layer 3 that is whitened after water absorption, the aluminum foil is preferably used because the whitening is less noticeable. The barrier layer 4 may be a single layer or a plurality of layers.

  The thickness of the barrier layer 4 is appropriately selected according to the form of the packaging container and the type of constituent material of the barrier layer, and is, for example, about 0.01 to 300 μm. More specifically, when the barrier layer is composed of a vapor deposition layer, the thickness is 0.01 to 0.2 μm, the coating layer is 3 to 30 μm, a film or sheet (including metal foil, vapor deposition film, and multiple layers). Then, it is about 5-300 micrometers.

  In addition to the above, the antibacterial layer 2, the water absorption layer 3, and the barrier layer 4 may each contain an additive. For example, the water absorption layer 3 may contain a gas absorbent such as an ethylene absorbent or an oxygen absorbent.

  The antibacterial film of the present invention may have other layers. As other layers, for example, a printed layer, a surface base material, an overcoat layer, etc. are provided outside the barrier layer 4 when used as a packaging bag, and an anchor coat layer, a primer coat layer, an adhesive layer, etc. are provided between the layers. Can do. Examples of the front substrate include polyethylene terephthalate (PET), nylon (ONY), polypropylene (OPP), and the like. The total thickness of the antibacterial film is, for example, about 60 to 150 μm, preferably about 80 to 120 μm. The antibacterial film may be either a film shape or a sheet shape.

  The typical layer structure of the antibacterial film is, from the outside to the inside, in the order of barrier layer / water absorption layer / antibacterial layer, barrier layer / gas absorbent-containing water absorption layer / antibacterial layer, barrier layer / water absorption layer / antibacterial layer / heat. Seal layer, barrier layer / gas absorbent-containing water absorption layer / antibacterial layer / heat seal layer, surface base material / barrier layer / water absorption layer / antibacterial layer, surface base material / barrier layer / water absorption layer / antibacterial layer / heat seal layer, Examples include a surface base material / printing layer / barrier layer / water absorption layer / antibacterial layer, and a surface base material / printing layer / barrier layer / water absorption layer / antibacterial layer / heat seal layer. In addition, the heat seal layer provided inside the water-absorbing layer and the antibacterial layer is preferably one that does not inhibit water absorption and antibacterial properties.

  The antibacterial film 1 of the present invention can be produced by laminating at least the antibacterial layer 2, the water absorbing layer 3 and the barrier layer 4 using a conventional laminating method such as coextrusion or laminating. In addition, when forming the laminated body of the antibacterial layer 2 and the water absorption layer 3, when using the method of carrying out lamination etc. after forming each film, until the film after film formation is used for the next process, transportation At times, there are many opportunities to come into contact with the atmosphere during the manufacturing process such as laminating, so that antibacterial and moisture-proof management is required. On the other hand, according to the method of obtaining a laminated film by co-extrusion of the resin composition constituting the antibacterial layer 2 and the resin composition constituting the water absorbing layer 3, management after film forming is easy to perform and during production and production. It is preferable because later antibacterial and moisture-proof effects can be prevented from being reduced. Moreover, since the antibacterial layer 2 exhibits antibacterial properties at the site where the kneaded antibacterial agent is in contact, it is not necessary to increase the film thickness, and it is desirable to reduce the film thickness in terms of cost. A method by coextrusion is preferred.

  The packaging bag of the present invention is at least partially formed by the antibacterial film of the present invention with the antibacterial layer inside. That is, the packaging bag of the present invention may be formed of the antibacterial film of the present invention alone, or may be formed of a combination of the antibacterial film and other packaging materials. The packaging bag of the present invention has a sealing layer on the peripheral edge, for example, a pouch having a packaging form (four-side sealing form) in which two packaging films are combined and sealed on four sides, and a gusset part on the bottom or side. Any of pouches (standing pouches, etc.), re-sealable forms in which members such as fasteners are provided, or a blister pack or the like may be used. The packaging bag which has the said form can be manufactured using a well-known thru | or usual method.

  FIG. 2 (a) is a schematic perspective view showing an example of the packaging bag of the present invention, and (b) is a schematic cross-sectional view taken along line AA in a state where an article is put in (b). The packaging bag shown in FIG. 2 (a) has three sides of a rectangular antibacterial film 1 and another laminated film 5 of the same shape sealed with heat seal (seal part 7), and a fastener on one side. (Chuck) 8 is attached. As shown in FIG. 2 (b), the packaging bag includes a pair of members 8a (on the inner surface side of the antibacterial film 1 and a laminated film 5 at positions facing each other across the article 6). It can be resealed by a fastener composed of (concave portions) and 8b (convex portions).

  The antibacterial film 1 and the laminated film 5 have antibacterial layers 2 and 2 ′ on the surface in contact with the article 6. The antibacterial film 1 has a configuration shown in FIG. 1, and the laminated film 5 has a configuration in which a barrier layer 4 ′ is laminated outside the antibacterial layer 2 ′. The antibacterial layer 2 ′ and the barrier layer 4 ′ have forms exemplified in the antibacterial layer 2 and the barrier layer 4, respectively. The total thickness of the laminated film 5 composed of the antibacterial layer 2 ′ and the barrier layer 4 ′ is, for example, about 60 to 150 μm, preferably about 80 to 120 μm. The fastener 8 is not particularly limited as long as it can be re-sealed (resealable) after opening, for example, a configuration in which continuously formed concave portions and convex portions are engaged (FIG. 2 (B)) or A configuration in which a plurality of tooth-shaped portions formed on both sides are alternately engaged can be utilized, and the resin fastener member can be attached to the bag body by a method such as heat fusion.

For example, the packaging bag with a fastener is formed into a film by co-extrusion of the resin composition constituting the antibacterial layer 2 and the resin composition constituting the water absorption layer 3, and the barrier layer 4 is laminated on the outer side of the water absorption layer 3. The laminated film 5 obtained by laminating the antibacterial film 1 obtained, the antibacterial layer 2 'and the barrier layer 4' is provided with fastener members 8a and 8b on the surface end portions on the antibacterial layers 2 and 2 'side of both films After that, the antibacterial layers 2 and 2 'are arranged so as to be on the inner surface side, sealed on three sides to form a bag, and after opening the fastener 8 and putting in the article, it is sealed by closing the fastener. Can be produced. If necessary, the inside of the packaging bag can be sucked or replaced with nitrogen or CO ₂ before sealing.

  According to the packaging bag of the present invention, the barrier layer prevents permeation of gas, water vapor and the like from the outside, the moisture absorption layer removes moisture inside the packaging bag, and further, the antibacterial layer provides an antifungal and antibacterial action. The quality of the contents can be kept stable for a long time. That is, since the inside of the packaging bag is maintained in a low-humidity environment in which microorganisms do not easily grow due to the water absorption layer, it is possible to suppress the growth of a wider variety of microorganisms as well as microorganisms that have an antibacterial effect due to the antibacterial layer. In particular, when used for packaging food, the freshness of the food can be maintained at a high level. In addition, the antibacterial layer 2 exhibits antibacterial properties at the site where the antibacterial agent contained in the layer comes into contact. For example, after opening a resealable packaging bag as shown in FIG. The antibacterial effect can be continuously obtained even when it is done.

  The contents (packaged items) enclosed in the packaging bag of the present invention do not contain a large amount of water and require antibacterial properties for quality control, such as food (processed products such as cheese and ham). , Confectionery, pharmaceuticals, cosmetics, luxury goods, precision equipment, machine parts, and the like. Moreover, these contents may have any form, such as a semi-liquid substance and a solid substance.

  Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited to these examples.

Example 1
Linear low density polyethylene (LLDPE) containing 5% by weight of a zinc oxide compound (antibacterial agent; trade name “SEABIO”, manufactured by Seawater Chemicals) and an ethylene-vinyl acetate copolymer (EVA) containing 30% by weight of magnesium sulfate ) And an antibacterial layer (LLDPE layer; thickness 30 μm, water vapor transmission rate 20 g / m ² · 24 h · atm) and water absorption layer (EVA layer; thickness 30 μm, water vapor transmission rate 150 g / m ² · 24 h · atm) A laminated sheet comprising: an aluminum foil (thickness: 7 μm) as a barrier layer, and a polyethylene terephthalate (PET) film (thickness: 30 μm) as a base material layer on the water absorption layer using an adhesive. A sheet having a layer structure of PET / aluminum foil / EVA / LLDPE was formed. After stacking the two obtained sheets so that the antibacterial layer is on the inside and sealing in three directions to produce a bag-like sheet, 20 g of cheese is left in the bag-like sheet and then left. One side was sealed to prepare an antibacterial pouch.
The antibacterial pouch containing the contents was allowed to stand at room temperature for 3 days, and then taken out and evaluated by visual inspection, fragrance, etc., and there was no decaying odor or discoloration and no mold was generated.
The cheese taken out is put in a pouch again, sealed with a seal, and then left for another 3 days at room temperature. After that, it is taken out and evaluated by visual inspection, aroma, etc. There is no smell or discoloration and no mold is generated. It was.

Comparative Example 1
In Example 1, an antibacterial pouch was produced in the same manner as in Example 1 except that a water absorbing layer was not provided and a barrier layer was provided on a sheet obtained by extruding the antibacterial layer alone.
The antibacterial pouch enclosing the contents was allowed to stand at room temperature for 3 days, and then taken out and evaluated by visual observation, fragrance, etc. As a result, it had a rotting odor and partially generated mold.
The cheese taken out is put in a pouch again, sealed with a seal, then left at room temperature for an additional 3 days, then taken out and evaluated visually, with fragrance, etc. There is a decaying odor and mold is generated on the entire surface. It was.

It is a schematic sectional drawing which shows an example of the antibacterial film of this invention. (A) is a schematic perspective view which shows an example of the packaging bag of this invention, (B) is an AA line schematic sectional drawing of the state which put the article | item in (A).

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Antibacterial film 2,2 'Antibacterial layer 3 Water absorption layer 4,4' Barrier layer 5 Laminated film 6 Contents 7 Seal part 8 Fastener 8a Recessed part (fastener member)
8b Convex part (fastener member)

Claims (2)

An antibacterial film in which a barrier layer, a water absorption layer and an antibacterial layer are laminated in this order. A packaging bag, at least part of which is formed of the antibacterial film according to claim 1 with the antibacterial layer inside.

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