JP3121887B2 - Sterilization and freshness-keeping pressure-sensitive adhesive sheet for packaged articles and sterilization and freshness-keeping method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bacteriostatic, bactericidal, and freshness preserving pressure-sensitive adhesive sheet in which an isothiocyanate ester is efficiently held by an adhesive, and a method of sterilizing and maintaining the freshness using the same. It is intended for the prevention of bacteria, fungi, microorganisms, etc., of a wide range of items to be packaged, including foods such as fruits and vegetables, fresh foods, dried foods and shells.

[0002]

2. Description of the Related Art Conventionally, as means for maintaining freshness, a vacuum pack or Ageless (registered trademark) has been used to prevent oxidation and propagation of bacteria.
Although a vacuum pack requires a special device, and an age-less package requires packaging in a packaging material together with the article to be packaged. In addition, many foods such as bread, fish, meat, and bento are packaged with a Saran film, a polyethylene (PE) film, or the like, or are simply placed in containers made of such materials. in this case,
Naturally, the shelf life was poor at room temperature, and it had to be stored in a refrigerator or the like.

By the way, isothiocyanates contained in mustard and wasabi have bacteriostatic and bactericidal activities, and they are bactericidal and bactericidal even at a very small vapor concentration of tens of ppm to hundreds of ppm irrespective of synthesis or nature. It is known that an effect can be obtained. Since this was reported, so far, isothiocyanates have been adsorbed on porous supports such as clay minerals or adsorbed on the surface of films and sheets to industrially control this bactericidal and bactericidal action. Attempts have been made to utilize, and some of them have been commercialized, for example, as freshness retaining materials.

[0004]

However, the conventional methods described above have not been able to make full use of the bacteriostatic and bactericidal actions of isothiocyanates. This is because, in these methods, many of the isothiocyanates are volatilized during the production process or storage and cannot carry an effective amount due to the high volatility of the isothiocyanates. In particular, when adsorbing on a porous carrier, it is necessary to provide a means for putting the bag into a bag having a sustained release property because the release rate is greatly dependent on the temperature, and it is also adsorbed on the surface of the film or sheet. In such a case, there are problems that it is difficult not only to impregnate the isothiocyanate in a sufficient amount to exert the effect but also to control the sustained release.

[0005]

Means for Solving the Problems As a result of intensive studies, the present inventors have found that by using a polymer that dissolves in or swells with isothiocyanates as an adhesive, The present inventors have found that it is possible to effectively impregnate and hold isothiocyanates while maintaining physical properties, and have overcome the above problems.

That is, the pressure-sensitive adhesive sheet for sterilizing and maintaining freshness of the packaged article of the present invention, as shown in FIG. 1, is on the base sheet 1 having a lower permeability to isothiocyanates than the packaging material of the packaged article. And a pressure-sensitive adhesive layer 2 impregnated with isothiocyanates.

In the drawing, a substrate sheet 1 having a polyethylene terephthalate (PET) film 1a provided with an Al vapor-deposited film 1b on one surface and having almost no permeability to isothiocyanates is used. still,
In the drawing, reference numeral 3 denotes an isothiocyanate-barrier release sheet provided with a silicone release treatment layer 3b on one side of a PET film 3a.

The pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer for impregnating and holding the isothiocyanates is (meth)
N-butyl acrylate, hexyl (meth) acrylate,
2-diethylbutyl (meth) acrylate, isooctyl (meth) acrylate, 2-methoxyethyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, decyl (meth) acrylate, dodecyl (meth) acrylate,
One or more (meth) acrylates such as tridecyl (meth) acrylate and (meth) acrylic acid, itaconic acid, maleic acid, maleic anhydride, hydroxyethyl acrylate copolymerizable with the esters. , Hydroxypropyl acrylate, acrylamide, dimethylacrylamide, methylaminoethyl methacrylate,
Acrylic adhesives such as copolymers with functional monomers such as methoxyethyl (meth) acrylate, vinyl adhesives such as ethyl vinyl ether, propyl vinyl ether, butyl vinyl ether, and 2-ethylhexyl vinyl ether; natural rubber; Isoprene-styrene block copolymer rubber, styrene-butadiene rubber,
There is a rubber-based adhesive containing a synthetic rubber such as polybutene rubber and butyl rubber as a main component. The above acrylic, rubber, and vinyl adhesives can be selectively used, but it is preferable to select and use acrylic adhesives. In particular, alkyl (meth) acrylates having 4 or more carbon atoms in the alkyl group can be used. A copolymer of the monomer and a copolymerizable monomer is preferred, and a crosslinked type is more preferred. In the pressure-sensitive adhesive, if necessary, a tackifier such as a terpene-based resin or a petroleum-based resin, liquid paraffin, animal or vegetable oil (eg, olive oil, soybean oil, beef oil, tongue fat), polybutene, lower isoprene, wax, etc. , A filler such as titanium oxide, zinc oxide, aluminum metasilicate, calcium sulfate, calcium phosphate, water and an emulsifier (eg, sorbitan monooleate, sodium lauryl sulfonate), and an emulsifier (eg, stearin) Magnesium oxide, aluminum stearate) and the like can also be blended. It is also soluble in isothiocyanates.
Isothiocyanates by dissolving or swelling
Any other adhesive that can be impregnated with
The adhesive can also be used.

As the isothiocyanate, various esters can be used regardless of an aliphatic ester such as an allyl ester or an alkyl ester of isothiocyanate, or an aromatic ester. In this case, it is preferable to use natural isothiocyanates contained in mustard extract and the like.

The above-mentioned isothiocyanates are preferably impregnated and held in an amount of about 0.1 to 50% by weight with respect to the pressure-sensitive adhesive layer.
/ M ² or more. When the pressure-sensitive adhesive layer is impregnated with an isothiocyanate, a solvent having good compatibility with the pressure-sensitive adhesive or a mixture of a fat or oil and an isothiocyanate can also be impregnated.

The pressure-sensitive adhesive sheet substrate for sterilizing and maintaining the freshness of the article to be packaged is selected in relation to the packaging material, but it is preferable to use a completely isothiocyanate-barrier substrate. . Examples of such a substance include polyethylene terephthalate, polycarbonate, vinylidene, acrylonitrile, a copolymer of ethylene polyvinyl alcohol, and metal foil.

In order to produce the pressure-sensitive adhesive sheet for sterilizing and maintaining freshness of the packaged object, for example, a base sheet having a barrier property against isothiocyanates such as an Al vapor-deposited PET film is mixed with an isothiocyanates. It can be produced by applying a pressure-sensitive adhesive that quickly dissolves or swells due to its compatibility to form a pressure-sensitive adhesive layer, and impregnated with an isothiocyanate ester. Isothiocyanates can be supported without waste. The method for impregnating the pressure-sensitive adhesive layer with the isothiocyanate is not particularly limited, such as gravure coating, Meyer bar coating, spray coating, curtain coating, stripe coating from a nozzle, and dipping. The step of impregnation is preferably performed at a temperature of the atmosphere including the pressure-sensitive adhesive layer at room temperature or lower.

Further, the method for sterilizing and maintaining freshness of a packaged object of the present invention is characterized in that the pressure-sensitive adhesive sheet is attached to an outer surface of a packaging material of the packaged item. That is, it is possible to sterilize or maintain freshness of the packaged object without destroying the packaging material.
The packaging material is not particularly limited as long as it is made of a composition having a lower barrier property than the pressure-sensitive adhesive sheet substrate with respect to isothiocyanate esters. By appropriately selecting the size of the pressure-sensitive adhesive sheet, the place of application, the time of application, and the amount of isothiocyanate impregnated and retained, extremely appropriate sterilization or freshness can be maintained.

[0014]

The present invention takes advantage of the fact that it adheres to everything the adhesive has by means of the above means, and the vapor of isothiocyanates can be introduced into the packaging of foods and the like without the need for special equipment. , It is possible to use a wide range of effects such as preserving the freshness of foods and the like, preventing fungi and preventing germs.

[0015]

Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples. Example 1 Allyl isothiocyanate was converted to 2-ethylhexyl acrylate (97% by weight) and acrylic acid 3
10% by weight of the copolymer acrylic pressure-sensitive adhesive
A pressure-sensitive adhesive sheet containing a weight% was prepared. Also, after putting bread and rice in a PE bag (120 mm x 85 mm x 0.08 mm) and sealing, the adhesive sheet is 2 cm x 2
After cutting to a size of cm, the release sheet was peeled off, affixed to a PE bag from the outside, and left at room temperature. After 2 weeks, no change was observed in the bread, and dew was observed on the inside of the bag. It was just.

As a control, bread and rice were put in a bag made of PE and sealed in the same manner as in Example 1, and then left at room temperature without sticking the pressure-sensitive adhesive sheet. After 10 days, it had spread almost all over the bread. In addition, the rice became moldy after about 4 days, and after 10 days, it became spoiled and could not keep its original shape.

Example 2 Three packs of boiled udon were placed at the center of the outer side of the PE package.
The same adhesive sheet as in Example 1 was cut into a square of 5 cm, and then the release sheet was peeled off and adhered. Separately, three packs without the adhesive sheet were prepared as controls. These six packs were stored at room temperature, and the change in freshness seven days after each treatment was compared. The observation results were as shown in Table 1 below. As shown in Table 1, a clear freshness-retaining effect by sticking the pressure-sensitive adhesive sheet containing allyl isothiocyanate was confirmed.

[0018]

[Table 1]

Example 3 Twelve sacks containing PE bags were divided into four groups of three sacks.
The group was set as a control (untreated group), and the other three groups were treated as in Example 1.
Table 2 shows the same pressure-sensitive adhesive sheet containing allyl isothiocyanate as described in Table 2.
Under the conditions shown in (1) above.

[0020]

[Table 2]

Then, each sample was stored at room temperature for a long time, and the following items were tested. 1) Mold generation status: 1, 3, and 7 days after application 2) Residual wasabi odor: 1 and 7 days after application The test results are shown in Table 3.

[0022]

[Table 3]

As described above, in the group to which the allyl isothiocyanate-containing pressure-sensitive adhesive sheet was adhered, generation of mold was suppressed in proportion to the size of the sheet. On the other hand, the wasabi smell only one day later ~
Although confirmed in all the groups, it was already reduced to an undetectable level after 7 days, suggesting that there was almost no effect on taste.

[0024]

In the case of a conventional vacuum pack or Ageless (registered trademark), it is necessary to perform packaging simultaneously with the article to be packaged on a packaging line, and the package is required to have hermeticity and airtightness. However, in the present invention using an adhesive sheet using isothiocyanates, even if there is a slight leak, the isothiocyanates are replenished from the adhesive sheet, so that even if the airtightness is small, sufficient sterilization and freshness maintaining effects can be obtained. Demonstrate. Furthermore, the time when this sheet is attached does not necessarily need to be on the production line, and the same effect can be obtained even if a general purchaser attaches the food after purchasing it.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a pressure-sensitive adhesive sheet for sterilizing and maintaining freshness of an article to be packed according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Substrate sheet 1a PET film 1b Al vapor deposition film 2 Adhesive layer 3 Barrier release sheet 3a PET film 3b Silicon release layer

Continuation of the front page (72) Inventor Yuichi Mizukami 3-2-1 -62-907, Minatojima Nakamachi, Chuo-ku, Kobe-shi, Hyogo (72) Inventor Shuzo Nakagawa 5-32-21, Inari, Soka-shi, Saitama (72) Inventor Hideaki Okabe 7-7-3 Tsuji, Urawa-shi, Saitama Prefecture Lintec Urawa Second Dormitory 506 (72) Inventor Kazuya Kato 7-7-3 Tsuji, Urawa-shi, Saitama Lintec Urawa Third Dormitory 210 (72) Inventor Nagaki Hiroshi 1-8-2, Kaedaoka, Hatoyama-cho, Hiki-gun, Saitama Prefecture (56) References Hikaru 3-111984 (JP, U) (58) Fields studied (Int. Cl. ⁷ , DB name) B65D 81 / 28 B65D 65/14 B65D 65/42

Claims (4)

(57) [Claims] 1. An article to be packaged comprising an adhesive layer impregnated with isothiocyanates and held on a base sheet having a lower permeability to isothiocyanates than a packaging material of the article to be packaged. Pasteurizing sheet for sterilization and freshness maintenance. 2. The pressure-sensitive adhesive layer wherein the alkyl group has 4 carbon atoms.
2. The pressure-sensitive adhesive sheet for sterilization and freshness maintenance according to claim 1, comprising a copolymer of the alkyl (meth) acrylate monomer and a monomer copolymerizable with the monomer. 3. The pressure-sensitive adhesive sheet for sterilization and freshness maintenance according to claim 1, wherein an isothiocyanate-barrier release sheet is adhered onto the pressure-sensitive adhesive layer. 4. A method for sterilizing and maintaining freshness of an article to be packaged, wherein the pressure-sensitive adhesive sheet for sterilizing and maintaining freshness of the article to be packaged according to claim 1 is attached to an outer surface of a packaging material of the article to be packaged.