JPH1189548A - Antibacterial water-absorbing sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prepare the subject sheet useful for improving quality keeping of a food such as a perishable food and free from giving ill effect on a human body by applying a cyclodextrin adduct of an antibacterial component on a water-absorbing sheet under specific conditions. SOLUTION: A cyclodextrin adduct of an antibacterial component having antibacterial activity and volatility such as an isocyanic acid ester, and calcium particles are dispersed in a mixed liquid prepared by mixing a natural resin binder to an alcoholic solvent, and the obtained suspension is applied to a water- absorbing sheet member. This process affords a water-absorbing sheet preferable in view of food sanitation by evenly applying the cyclodextrin adduct.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antibacterial water-absorbing sheet used for improving the shelf life of foods such as fresh foods.

[0002]

2. Description of the Related Art Conventionally, antibacterial sheets have been widely used as a freshness retaining material for fresh foods. Examples of the antibacterial sheet include Japanese Unexamined Utility Model Publication No. 3-111198,
As disclosed in JP-A-222437 and JP-A-6-153779, cyclodextrin clathrates (hereinafter referred to as CD clathrates) of antibacterial components such as isothiocyanates having antibacterial properties and volatile properties are disclosed. Are sometimes scattered inside the sheet material, or those in which a urethane-based resin binder or the like is provided as a coating layer on the surface or between the sheet materials or dispersed between the sheet materials. Have been.

[0003] These antibacterial sheets are laid in a packaging container for packaging fresh food, and when the packaging container is sealed with a wrap or the like, the antibacterial component is diffused as gas and the antibacterial component diffuses as a gas. Fill the container. From this, it is said that the growth of microorganisms on the surface of the fresh food that is not in contact with the antimicrobial sheet can be suppressed by the antimicrobial component.

[0004] As a method for producing such an antibacterial sheet, a urethane resin or a thermoplastic resin is used.
After mixing the D clathrate, or dispersing the CD clathrate in a solution in which the thermoplastic resin is dissolved in a solvent such as ethyl acetate, isopropyl alcohol, or toluene, apply the mixture to paper or a film, and then volatilize the solvent. Although the method is a general method, as a method of kneading into a thermoplastic resin, there is a method of forming a master batch and then making it into a film with an extruder or the like. However, the oily antibacterial component in the CD clathrate diffuses, and the oily antibacterial component does not remain.

[0005] Further, C containing oily antibacterial agent inside the sheet
There is a method of dispersing the D clathrate, etc. However, it is very difficult to disperse the CD clathrate containing the oily antibacterial agent uniformly, there is a lot of variation between sheets, and it is difficult to obtain a uniform product. there were. In addition, problems such as separation of the CD inclusion particles from the fibers also occurred.

Japanese Patent Application Laid-Open No. 9-224560 discloses a method in which a cyclodextrin clathrate containing a urethane resin and an oily antibacterial is dissolved in a solvent and processed into a film or the like. Further, in this method, a solvent such as ethyl acetate, isopropyl alcohol, and toluene is used, and it is said that there is an advantage that it can be uniformly applied to the coated surface as compared with the above-mentioned dispersing method.

[0007]

However, since the above-mentioned antibacterial sheet uses a solvent such as ethyl acetate, isopropyl alcohol, and toluene, a part of the solvent is included in cyclodextrin, and the inclusion It has been found that these solvents have the serious disadvantage that they evaporate during use. For example, when a sheet containing ethyl acetate is used for sashimi such as tuna, there is a problem in food hygiene that reddish sashimi such as tuna changes to earthy color due to the ethyl acetate volatilized during use. I have. Furthermore, since the urethane-based resin is used, it cannot be used so as to come into direct contact with food, and even when not used, the effects of residual monomers, free isothiocyanate, etc. are of concern in food hygiene.

[0008]

SUMMARY OF THE INVENTION In view of the above circumstances, the present invention provides an antibacterial sheet using a cyclodextrin clathrate of an antibacterial component such as isothiocyanate having antibacterial properties and volatile properties. , Heating or even C
D. A solvent which does not include a step of using water for promoting the release of the antibacterial component from the clathrate, and which may cause the above-mentioned problems in food hygiene, and a urethane-based solvent which may cause similar problems The present inventors have made intensive studies to obtain an antibacterial water-absorbing sheet coated with the above-mentioned CD clathrate uniformly without using a resin or the like. That is, the present invention disperses a cyclodextrin clathrate containing an oily antibacterial agent having antibacterial properties and volatility and calcium particles in a mixture obtained by mixing a natural resin binder with an alcohol solvent, and the dispersion Is applied to a water-absorbent sheet-like member.

The water-absorbing sheet-like member used in the present invention is not particularly limited as long as it has a water-absorbing property. Paper, cloth made of natural fibers such as pulp and cotton, and synthetic fibers such as polyester and acrylic, Water-permeable and water-absorbing sheets, such as nonwoven fabrics, can be mentioned. Further, a sheet in which water-absorbing resin particles are held by entanglement between fibers in the sheet, a sheet in which water-absorbing resin particles are dispersed between the sheets, or a synthetic resin foam having open cells such as polyurethane foam There is one that clamps the body.

Examples of the water-absorbing resin include starch-acrylate graft polymer, carboxymethylcellulose crosslinked product, vinyl alcohol-acrylate copolymer, polyacrylonitrile hydrolyzate, crosslinked polyacrylate, modified polyvinyl Examples include alcohols, acrylic acid polymers, acrylate / acrylamide copolymers, isobutylene / maleic anhydride copolymers, etc., but are not particularly limited as long as they are water-absorbing materials.

The oily antibacterial agent having antibacterial properties and volatility used in the present invention is an extract containing isothiocyanates which are volatile at normal temperature and have a bactericidal or bacteriostatic action as an antibacterial action. Things. The reason why such an isothiocyanate is used is that an extract containing an isothiocyanate as a main component is recognized as an existing additive in food hygiene and has an antibacterial property. .

Extracts containing isothiocyanate as a main component include allyl isothiocyanate (CH ₂ = CHCH ₂ NCS), which is a pungent component of mustard and wasabi, phenyl isothiocyanate, methyl isothiocyanate, ethyl isothiocyanate, Extracts mainly containing propyl isothiocyanate, isopropyl isothiocyanate, butyl isothiocyanate, isobutyl isothiocyanate, isoamyl isothiocyanate, benzyl isothiocyanate, cyclohexyl isothiocyanate, and the like can be used.

As the cyclodextrin for inclusion of the oily antibacterial agent, α-cyclodextrin, β-cyclodextrin and γ-cyclodextrin can be used. However, since the oily antibacterial agent has good inclusion and economical efficiency, β-cyclodextrin is preferred. The above-mentioned cyclodextrin is used because cyclodextrin has high safety in food hygiene and has a property of stably and more effectively exerting the antibacterial action of the oily antibacterial agent. That is, cyclodextrin is chemically stabilized in the inclusion compound of the oily antibacterial agent,
It is intended to ensure long-term stability and effectiveness of the encapsulated oily antibacterial agent by eliminating emission, deodorizing, preventing oxidation, and suppressing photolysis.

Furthermore, since the cyclodextrin containing the above-mentioned oily antibacterial agent promotes the emission of the above oily antibacterial agent in the presence of water such as drip or the like, the oily antibacterial agent is first placed on the food. Is dissipated and the concentration of the oily antibacterial agent can be efficiently increased, so that the concentration of the oily antibacterial agent can be controlled. Moreover, the cyclodextrin clathrate containing the above oily antibacterial agent is less hygroscopic than inorganic carriers such as zeolite, so that it is not affected by the atmospheric humidity in the food packaging, A stable volatile concentration can be obtained, and an unpleasant odor generated from food can be removed by the deodorizing effect.

The natural resin binder used in the present invention is soluble in an alcohol-based solvent and includes, for example, shellac and copal resin. Such a natural resin binder is preferable because it can be used directly in contact with food without being affected by residual monomers and the like. Among these, shellac is particularly preferred from the viewpoint of solubility in ethyl alcohol.

The cyclodextrin clathrate containing the oily antibacterial agent may be applied to the water-absorbent sheet member in an amount of 100 to 400 parts by weight based on 100 parts by weight of the natural resin binder. preferable. this is,
When the cyclodextrin clathrate containing the above-mentioned oily antibacterial agent is less than 100 parts by weight, the cyclodextrin clathrate containing the oily antibacterial agent is covered with the natural resin binder, and the oily antibacterial agent that is clathrated hardly dissipates. If the amount is more than 400 parts by weight, the cyclodextrin clathrate containing the oily antibacterial agent cannot be held in the water-absorbing sheet member.

Examples of the alcohol solvent that can be used in the present invention include solvents such as ethyl alcohol, cinnamyl alcohol and decanol. The alcohol-based solvent has safety in food hygiene and has a property that the solvent itself can exert an antibacterial action, and ethyl alcohol is particularly preferable.

The calcium particles used in the present invention include bone charcoal, calcined calcium, uncalcined calcium, tricalcium phosphate, calcium hydrogen phosphate and the like.
The purpose of using such calcium particles is to prevent the cyclodextrin clathrate containing the oily antibacterial agent from being coalesced in a mixture of a natural resin binder and an alcoholic solvent to improve dispersibility. It is. Among them, those containing at least one calcium particle selected from bone charcoal and calcined calcium are particularly preferable. Also,
The calcium particles preferably have an average particle size of 0.1 to 20 μm.

As a method for applying a mixed solution containing a cyclodextrin clathrate containing an oily antibacterial agent as described above to a water-absorbing sheet-like member, a gravure coater, a roll coater, a reverse roll coater, a kiss coater Etc. can be preferably used. In particular, a gravure coater is preferable from the viewpoint of coating stability. In the present invention, the amount of cyclodextrin inclusion complex inclusion complex of oily antibacterial agent for water-absorbent sheet-like member is preferably 0.01 to 10 g / m ^2, more preferably 0.1-5 g / m ^2. When the compounding amount is less than 0.01 g / m ² , the antibacterial effect is reduced, and when the compounding amount exceeds 10 g / m ² , it is difficult to stably maintain the water-absorbing sheet member. Because it becomes.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described below in detail with reference to examples and the like. (Production Example 1) Allyl isothiocyanate, which is an oily antibacterial agent having antibacterial properties and volatility, was dissolved in a solvent [water /
An ethanol mixture (mixing ratio of 1: 9)] was mixed to obtain 20 parts by weight of allyl isothiocyanate with respect to 100 parts by weight of β-CD, and then the mixture was dried under reduced pressure. The solvent was removed to obtain β-CD inclusion particles in which the allyl isothiocyanate was included in β-CD.

Example 1 1.5 kg of shellac resin was dispersed in 5.5 kg of ethanol, and the β-
2.7 kg of CD clathrate particles were charged and dispersed. Then
0.3 kg of calcium particles was dispersed in the above mixture to obtain a mixed dispersion. 5 g / m ² of the obtained mixed dispersion was applied to a natural pulp sheet by a gravure coater to obtain an antibacterial water-absorbing sheet.

Comparative Example 1 An antibacterial water-absorbing sheet was obtained in the same manner as in Example 1 except that 5.5 kg of ethanol was changed to 5.5 kg of ethyl acetate.

Comparative Example 2 An antibacterial water-absorbing sheet was obtained in the same manner as in Example 1 except that 5.5 kg of ethanol was changed to 5.5 kg of toluene.

Using the antibacterial water-absorbing sheets obtained in Example 1 and Comparative Examples 1 and 2, the effect on sashimi was examined by the following method. First, the above antibacterial water-absorbing sheet cut into about 7 cm squares was laid under the cut of the red tuna, and the diameter was 95 mm.
And placed in a petri dish having a height of 10 mm, sealed and sealed with parafilm, and stored in a refrigerator at a temperature of 5 ° C. for 12 hours. At this time, the color, taste, and odor in the tray at the start of storage and after 12:00 were each subjected to a sensory test and evaluated. Table 1 shows the results.

[0025]

[Table 1]

Thus, it is clear that the solvent used is included in the cyclodextrin, and in particular, in the case of ethyl acetate, it has been found that the product has a fatal effect such as discoloration of tuna. The concentration of ethyl acetate in the petri dish of Comparative Example 1 was 330 ppm as measured by gas chromatography.

(Example 2) A solution containing 15 kg of shellac resin per 70 kg of ethanol solution was prepared as follows:
Mixed particles 1 in which the β-CD clathrate particles and calcium particles obtained in Production Example 1 were blended in a weight ratio of 9: 1.
0 kg was dispersed. The results of determining the stability of the mixed dispersion by changing the mixing ratio of the shellac resin and the mixed particles as shown in Table 2 are also described. The liquid stability was determined by the presence or absence of separation of the ethanol layer. When the separation of the mixed dispersion liquid is severe, when coating with a gravure coater, not only will not be able to obtain the target coating amount because only the ethanol liquid is applied at the start, but also if the coating is continued The solid content becomes rich, the application amount to the water-absorbing sheet becomes larger than the target application amount, and finally, if the liquid viscosity is high, it will not be able to get on the gravure coater.

[0028]

[Table 2]

Comparative Example 5 A solution containing 15 kg of shellac resin per 55 kg of ethanol solution was
Only the β-CD clathrate particles obtained in Production Example 1 were mixed and dispersed, but the β-CD clathrate particles tended to form agglomerates and could not be dispersed.

In order to mix and disperse a cyclodextrin clathrate containing an oily antibacterial agent under the condition of an ethanol solution having a shellac resin ratio of about 20% as a natural resin binder, calcium particles are added. It is essential that the amount of natural resin binder is 1
Even if the mixed particles are 100 parts by weight or less or 400 parts by weight or more with respect to 00 parts by weight, the dispersion is not stable.

The antibacterial water-absorbing sheet prepared in Example 1 was subjected to an antibacterial test. The emission amount of allyl isothiocyanate from the sheet was measured and found to be 0.1 mg / l. E. coli K12 strain (IFON) was added to 9 ml of physiological saline.
o. 3301) was added, and 10 antibacterial water-absorbing sheets cut into 1 × 1 cm were put. As a control, the same untreated water-absorbing sheet as used in Example 1 was similarly used.
One containing 0 sheets was prepared and cultured at 35 ° C. and 110 rpm, and the number of bacteria after 6 hours was measured. Table 3 shows the results.
The number of bacteria was indicated by the number of bacteria per ml.

[0032]

[Table 3]

As described above, the antibacterial water-absorbing sheet of Example 1 is used for food trays in which fresh foods, for example, tuna cuts are placed, wrapped and sealed, and arranged and stored in a refrigerated display case or the like. When used in a laid state, the portion of the fresh food that comes into contact with the antibacterial water-absorbing sheet is antimicrobial by the oily antibacterial agent scattered from the CD clathrate containing the antibacterial and volatile oily antibacterial agent, and is harmful. The growth of microorganisms such as bacteria is suppressed.

Further, the drip flowing out of the fresh food is antibacterial by directly contacting the oily antibacterial agent radiated from the CD inclusion particles, thereby preventing the generation of an odor caused by microorganisms in the drip. In addition, since it is absorbed between natural pulp in the water-absorbing sheet, contact with fresh food is prevented, and discoloration of the fresh food due to contact with drip can be avoided.

Furthermore, the portion of fresh food that does not come into contact with the antibacterial water-absorbing sheet is also antibacterial by the CD inclusion particles. That is, the allyl isothiocyanate included in the CD inclusion particles is diffused from the antibacterial water-absorbing sheet and fills the food tray in the closed state. As a result, the allyl isothiocyanate reaches the non-contact portion of the fresh food with the antibacterial water-absorbing sheet, so that the antibacterial action is exerted on the non-contact portion.

[0036]

As described above, the antibacterial water-absorbing sheet of the present invention is an antibacterial sheet using a cyclodextrin clathrate of antibacterial components such as isothiocyanates having antibacterial properties and volatile properties. In addition, a solvent that does not include a step of using water that promotes the release of the antibacterial component from the heating and, furthermore, the CD clathrate and that may cause a food hygiene problem as described above, Without using a urethane-based resin or the like which may cause the problem of
An antibacterial water-absorbing sheet coated with D clathrate uniformly can be obtained.

Further, since CD inclusion particles and calcium particles are mixed and dispersed with a natural resin binder using an alcoholic solvent, and this mixed dispersion is applied to a water-absorbent sheet, tuna and the like are used. The growth of harmful microorganisms such as psychrotrophs in fresh food can be significantly suppressed not only in the area that comes into contact with the antibacterial water-absorbent sheet, but also in the areas that do not come in contact with it. Even in this case, it is possible to obtain an antibacterial water-absorbing sheet that is not harmful to food such as tuna and the human body and is safe for food hygiene.

Further, in the embodiment using allyl isothiocyanate or cyclodextrin as an oily antibacterial agent, or a natural resin binder, ethyl alcohol or the like as an alcohol-based solvent, all natural products or food-safe compounds are used as constituent materials. Since it is used, it can be used for a tray or the like on which food is placed and packed, and further, it can be used in direct contact with food. Specifically, by laying a fresh food or the like on a water-absorbent sheet in a food tray wrapped in a wrap, the oily antibacterial agent is diffused from the cyclodextrin clathrate and is applied to the surface of a non-contact portion of the fresh food or the like. It can also exhibit high antibacterial properties. Therefore, it can be suitably used for storing fresh food in the food tray.

──────────────────────────────────────────────────の Continuation of the front page (51) Int.Cl. ⁶ Identification symbol FI B65D 81/26 B65D 81/26 H 85/50 85/50 A (72) Inventor Tetsuharu Hirota 7-3-Mitsugaoka, Nerima-ku, Tokyo 7-1109 Hikarigaoka Park Town (72) Inventor Shigeru Ozaki 13-10-1 Minamikamodai, Kamo-cho, Soraku-gun, Kyoto (72) Inventor Hitomi Kawakubo 1808-6, Shiromachi, Yama-gun, Yamato-gun, Nara Prefecture

Claims (2)

[Claims] 1. A cyclodextrin clathrate containing an oily antibacterial agent having antibacterial properties and volatility and calcium particles are dispersed in a mixture obtained by mixing a natural resin binder with an alcohol-based solvent, and the dispersion is dispersed. An antibacterial water-absorbing sheet, which is applied to a water-absorbing sheet-like member. 2. The antibacterial according to claim 1, wherein the cyclodextrin clathrate is applied to the sheet-like member in an amount of 100 to 400 parts by weight based on 100 parts by weight of the natural resin binder. Water absorbing sheet.