JPH09202361A - Resin composition for preserving freshness and film sheet or container for preserving freshness molded by using the composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively adsorb and remove ethylene gas generated by aspiration of a agricultural food or cut flowers, provide a germicidal effect to suppress propagation of microorganisms by application of far infrared rays to preserve freshness for a long time by blending a specific wt.% of crushed Natsume-stone powder into synthetic resin. SOLUTION: A thermoplastic resin which is easy to mold into a film or a sheet and easy to obtain an arbitrary shape may be preferably used. A ratio of crushed Natsume-stone powder to be blended into the synthetic resin is 2 to 300wt.% based on 100wt.% of the synthetic resin. The crushed Natsume-stone powder adsorbs ethylene gas and further odorant such as ammonia and also can preserve freshness of agricultural food such as vegetables and fruits and cut flowers by far infrared rays emitted from the crushed stone powder. However, less than 2wt.% of the powder cannot obtain a required effect for maintaining freshness, and more than 300wt.% may cause a packing material or a container for maintaining freshness which has been hardened after melting and kneading to be fragile or poor in moldability.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a resin composition for keeping freshness, which is used as a packaging material or container for agricultural foods and retains its freshness for a long period of time, and a film for keeping freshness formed by using the resin composition. -It relates to a sheet or a container for keeping freshness.

[0002]

2. Description of the Related Art Agricultural foods such as vegetables and fruits have a limited harvesting time, and are consumed by respiration in the time lapse from when the agricultural foods are harvested in the field until they are sold. The value of the food will gradually decrease as it progresses.

In fact, among agricultural foods, fruits and vegetables breathe for a while after harvesting, and exhaustion due to breathing progresses with time, and by this breathing, metabolites such as water and carbon dioxide accumulate, and with the passage of time. The overheated state facilitates the growth of microorganisms, and the carbon dioxide generated by itself reduces the vitality of fruits and vegetables.

In particular, this phenomenon is prominent in fruits with green peel such as Sudachi and Kabosu, and fruits such as peach, loquat and strawberry which have a short pain and a short duration.

Some vegetables, such as leafy vegetables, have a "wilting phenomenon" such as lettuce, spinach or broccoli when they are separated from the plant body, and pain such as cucumber and tomato after harvesting. However, there are some vegetables that have a short shelf life.

For this reason, attempts have been made to preserve the harvested agricultural food for a long period of time while maintaining the freshness at the time of harvesting.

[0007] For example, recently, new technologies such as CA storage for increasing the concentration of carbon dioxide gas in agricultural food stores and packaging, or reduction of oxygen concentration to suppress breathing have been put to practical use, and the preservation period of agricultural foods is extended. It has become possible to do.

However, CA storage cannot be used easily because of the problem of carbon dioxide gas damage in some cases.

[0009] Further, a method has been proposed in which fresh agricultural products are stored at a low temperature in order to maintain the freshness, or are stored in that state after being rapidly frozen, but this method will be established in the future with the establishment of a cold chain. It is speculated that practical application will further develop. In other words, in this case, the temperature is lowered to suppress respiration, thereby suppressing metabolism and maintaining freshness for a long period of time.

However, low-temperature preservation or freezing preservation remarkably impairs the texture of agricultural foods. Therefore, even when it is stored at low temperatures or frozen, the color and taste deteriorate, and the quality is considerably poor after storage and it is fresh. It may have a completely different texture. Further, in such a state, the storage stability after that is remarkably affected, and the discoloration and the offensive odor are accelerated. Furthermore, it should be noted that some vegetables may cause low temperature damage when the temperature is low, and moreover, like vegetables, vegetables have a transpiration effect of water during storage, which often reduces the food value.

[0011] In particular, the above-mentioned storage method is not only large-scaled and costly, but also cannot be adequately dealt with in the process of food distribution and long-term storage of food in ordinary households.

Therefore, recently, Japanese Examined Patent Publication No. 64-215, Japanese Unexamined Patent Publication No. 1-207339, and Japanese Unexamined Patent Publication No. 64-3.
1838, JP-A-63-309136, JP-A-63-280744, JP-A-1-28222.
No. 6, JP-A-63-183367, and JP-A-Sho 6
JP-A-3-161818 and JP-A-63-151451.
As disclosed in Japanese Unexamined Patent Application Publication No. 2003-242242, packaging materials for keeping the freshness of agricultural foods have been proposed.

Of these, in particular, JP-A-63-151
As disclosed in Japanese Patent No. 451 gazette, a thermoplastic resin layer and a thermoplastic resin layer containing 2 to 50% by weight of a porous powder as a packaging material for maintaining freshness of agricultural foods such as vegetables and fruits are constituent layers. Is proposed to include at least two layers.

In this case, the particle size of the porous powder is, for example, 100-3000 mesh, preferably 200-3000 mesh.
The material is 2000 mesh, and as the material, for example, zeolite, shirasu, silica, activated alumina, montmorillonite, activated carbon, Otaniishi or cristobalite is used.

The porous powder is adapted to adsorb and remove a small amount of ethylene gas generated during storage of vegetables and fruits, and to adsorb and remove offensive odor gases such as ammonia.

[0016]

The above-mentioned packaging material for keeping freshness adsorbs and removes ethylene gas which promotes spoilage of vegetables and fruits, thereby maintaining the freshness of agricultural products. In addition to insufficient adsorbing power for the product gas such as ethylene gas, there are the following problems.

That is, the cause of spoilage of agricultural foods is not only the deterioration of freshness due to ethylene gas, but also the propagation of microorganisms in the time course from when agricultural foods are harvested in the field to when they are sold. To do. At this time, the taste is changed or a strange odor is generated, which makes it difficult to eat.

For example, most agricultural foods contain starchy substances or sugars, and their decomposed products contain many aldehydes and alcohols in addition to organic acids, and sourness can be used to detect spoilage.

Microorganisms related to spoilage of agricultural foods are bacteria, but fungi can also propagate in foods and cause spoilage, especially in humid places such as Japan.

Microorganisms are roughly classified into three types: bacteria, yeasts and filamentous fungi. Bacteria have a spherical shape, a rod shape, a spiral shape, and are proliferated by division. As typical spoilage bacteria, there are Bacillus subtilis, potato fungus, or morphobacterium, and there are bacteria that anaerobically spoil, and , Some spoilage bacteria make spores.

[0021] Yeast is an elliptic single cell, and some yeasts act on sugars to produce off-flavor substances and also spoil pickles and liquors.

Further, the filamentous fungus is a microorganism which is called a fungus, which grows and propagates hyphae. A sporangium is formed at the tip of the hypha, and the spores proliferate.

As described above, spoilage of agricultural foods is caused by the reproduction of microorganisms. However, conventional packaging materials for maintaining freshness cannot prevent the reproduction of microorganisms, and therefore can be used for maintaining the freshness of agricultural foods. As a packaging material, was not completely satisfactory.

According to the present invention, by blending Natsume crushed stone powder with a synthetic resin to adsorb ethylene gas due to the Natsume crushed stone powder and further offensive odor substances such as ammonia, the far infrared rays irradiated from Natsume crushed stone powder produce vegetables. It is an object to provide a resin composition for maintaining freshness that retains the freshness of agricultural foods such as fruits and fruits or cut flowers for a long period of time, and a film / sheet for maintaining freshness or a container for maintaining freshness formed by using the resin composition. To do. Thus, after harvesting the agricultural foods and cut flowers, the freshness of the agricultural foods and cut flowers is suppressed from decreasing during storage and during their distribution period, and further during storage of the agricultural foods and cut flowers at home.

That is, the present inventor has conducted various studies on packaging materials that can maintain the freshness of agricultural foods and cut flowers for a long period of time, and as a result, effectively adsorbs and removes ethylene gas generated by respiration of agricultural foods and cut flowers. In addition, it was found that the irradiation of far infrared rays exerts a bactericidal effect and an effect of suppressing the growth of microorganisms, and as a result, the freshness of agricultural foods and cut flowers can be maintained for a long period of time.

[0026]

In order to achieve the above object, the resin composition for maintaining freshness according to the present invention contains 2 to 300 parts by weight of Natsume crushed stone powder with respect to 100 parts by weight of synthetic resin. Is characterized by.

The resin composition for maintaining freshness of the present invention will be described in more detail as follows. The synthetic resin used in the present invention can be formed into a film or a sheet as described below, or can be packaged with agro-foods such as box-shaped or bottomed cylinders or cut flowers, or by molding, a container for agro-foods or cut flowers. Although a thermoplastic resin or a thermosetting resin may be used as long as the above can be obtained, a thermoplastic resin is preferable because it can be easily formed into a film or a sheet and a container having an arbitrary shape can be easily obtained.

Specifically, for example, polyethylene (PE)
(Bottom density polyethylene, high density polyethylene), polyethylene terephthalate (polyester), methacrylic resin, polymethylpentene, polypropylene, polystyrene (polystyrene for general use, polystyrene for impact, polystyrene foam), polyvinyl chloride, polyvinylidene chloride, ABS resin , AS resin, butadiene resin, ethylene / vinyl acetate copolymer, nylon (polyamide), polybutene-1, polycarbonate, ethylene vinyl alcohol copolymer, ionomer and the like.

In the present invention, Natsume crushed stone powder is blended with the synthetic resin. The blending ratio of the Natsume crushed stone powder is preferably 2 to 300 parts by weight with respect to 100 parts by weight of the synthetic resin, If it is less than 2 parts by weight, it is difficult to obtain the desired freshness-retaining effect. On the other hand, if it exceeds 300 parts by weight, the freshness-retaining packaging material or container that has been cured after melt-kneading becomes brittle, or the melt composition is It is not preferable because various adverse effects such as poor fluidity and poor moldability occur.
Therefore, within this range, it is more preferable to add 3 to 150 parts by weight of Natsume crushed stone powder to 100 parts by weight of the synthetic resin, and most preferably 5 to 100 parts by weight.

The crushed Natsume crushed stone powder used in the present invention is not particularly limited in particle size as long as it has good dispersibility with the synthetic resin, but is generally 50 μm or less, preferably 0.01 to 10 μm. This Natsume crushed stone powder has fine pores of several angstroms to several hundred angstroms, has an extremely high adsorbing ability for generated gases such as ethylene gas and ammonia, and irradiates far infrared rays with a wavelength of 4 to 15 microns. It is a thing.

In the present invention, it is preferable to use a coupling agent in order to enhance the binding force and affinity between the synthetic resin and Natsume crushed stone powder. This coupling agent is blended with the synthetic resin and Natsume crushed stone powder. Although it is good, by coating Natsume crushed stone powder with a coupling agent in advance and blending Natsume crushed stone powder coated with this coupling agent and synthetic resin, the amount of coupling agent used can be reduced. It is more preferable for further enhancing the binding force and affinity between Natsume crushed stone powder and synthetic resin.

As a method for coating Natsume crushed stone powder with a coupling agent, for example, the coupling agent is dissolved or dispersed in water or an organic solvent, and Natsume crushed stone powder is immersed in this solution, or this solution is added to Natsume crushed stone powder. It is possible to employ a method of spraying or attaching to the surface of the Natsume crushed stone powder and then drying.

The coupling agent is not particularly limited as long as it enhances the affinity and binding force between Natsume crushed stone powder and synthetic resin, and a silicone coupling agent,
Examples thereof include at least one selected from organic titanium-based coupling agents, phosphoric acid esters, phosphonates, phosphorous acid esters, polyphosphoric acid or metal salts thereof, boric acid or borax.

As the silicone coupling agent, vinyltrichlorosilane, vinyltris (βmethoxyethoxy) silane, vinyltriethoxysilane, vinyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, β- (3,4 epoxy). Cyclohexyl) ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, N-β (aminomethyl) γ-aminopropyltrimethoxysilane, N-β (aminomethyl) γ-aminopropylmethyldimethoxysilane, γ-
Aminopropyltriethoxysilane, N-phenyl-γ
Examples thereof include -aminopropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-chloropropylmethoxysilane, vinyltriacetoxysilane and the like.

Examples of the organotitanium coupling agent include alkyl titanate, titanium acylate and titanium chelate. Among these, alkyl titanate which exhibits particularly excellent crosslinkability is preferable.

Examples of the alkyl titanate include tetraisopropyl titanate, tetraisopropyl titanate polymer, tetrabutyl titanate, tetrabutyl titanate polymer, tetrastearyl titanate, 2-ethylhexyl titanate, a mixture of tetraisopropyl titanate and tetrastearyl titanate, or dibutyl titanate. Examples thereof include polymers, and examples of the titanium acylate include isopropoxytitanium stearate, and examples of the titanium chelate include titanium acetylacetonate and titanium lactate.

Examples of the phosphoric acid ester include ethyl phosphate, butyl phosphate or isoamyl phosphate, and examples of the phosphonate include diphenylphenylphosphonate, dimethylmethylphosphonate, diethylethylphosphonate and bis- (2- Examples thereof include ethylhexyl) -2-ethylhexylphosphonate and dibutylbutylphosphonate, and examples of the phosphite include dimethyl phosphite, diethyl phosphite, diisopropyl phosphite, dioctyl phosphite, and the like.

The amount of the coupling agent added is preferably 10% by weight or less, and particularly preferably 0.01 to 10% by weight, based on the Natsume crushed stone powder. It is not preferable because the effect of the agent cannot be sufficiently obtained. On the other hand, when it exceeds 10% by weight, it is meaningless and economically disadvantageous, and the adsorbability of the product gas such as ethylene gas and ammonia decreases. It is not preferable because it may occur.

Further, in the present invention, Natsume crushed stone powder 100
For parts by weight, Otani stone, zeolite, cristobalite, clinoptilolite, calcium silicate, acid clay,
1 to 30 parts by weight of at least one adsorbent selected from activated clay, bentonite, diatomaceous earth, sulfur stone, perlite, activated alumina or talc may be added.

It is meaningless to mix the adsorbent in an amount of less than 1 part by weight per 100 parts by weight of Natsume crushed stone powder,
On the other hand, if the amount exceeds 30 parts by weight, irradiation of far infrared rays will be hindered, and in any case, it is not preferable.

In the present invention, colorants such as pigments and dyes, antiaging agents, tackiness regulators, tackiness improvers, defoamers, thickeners, modifiers, antifungal agents, antibacterial agents, sterilizers. Although addition of other additives such as agents, deodorants or deodorants is not hindered, in this case, the amount of addition is such that the synthetic resin 100
It is preferably 0.05 to 10 parts by weight with respect to parts by weight, if less than 0.05 parts by weight, the effect of the addition becomes poor, it is not preferable, while if more than 10 parts by weight, ethylene gas It is not preferable because it may adversely affect the adsorptivity of the produced gas such as ammonia and ammonia, or may hinder the irradiation of far infrared rays.

In the resin composition for maintaining freshness of the present invention, synthetic resin and Natsume crushed stone powder are essential components, or synthetic resin and Natsume crushed stone powder, and further the above-mentioned coupling agent or adsorbent of generated gas. Although at least one of them is blended, no special kneading device or kneading method is required for mixing these components, and a conventional kneading device or kneading method may be used. Specifically, the compositions may be mixed with each other, for example, by dry blending, or may be uniformly kneaded while being heated and melted with, for example, a kneader.

When these components are mixed, kneaded while being heated and melted, and then cured, it is possible to prevent the components from being scattered to the surroundings, and it is preferable for securing a predetermined composition. Of course, when curing the resin composition for maintaining freshness that has been heated and melted, it is formed or molded into various shapes such as powder, granules, fibers, pellets, agglomerates, sheets and strips, and it is easy to transfer and handle. In addition, it may be easier to store and manage, and it can be melted again at the construction site, and can be wrapped in a film, sheet, box, bottomed tube, or any other shape to maintain freshness. The material or container may be formed.

When the freshness-retaining resin composition of the present invention is used to form a freshness-keeping packaging material or container having an arbitrary shape,
It is possible to directly use the melt-kneaded freshness-keeping resin composition obtained in the process of producing the freshness-keeping resin composition, and also powder, granular, fibrous, pellets, lumps, sheets and strips. It is possible to melt-knead the freshness-maintaining resin composition formed or molded into various shapes such as a body using a suitable pot, pot, kneader, etc., and use it.

The freshness-preserving film / sheet of the present invention comprises:
In order to achieve the above object, the resin composition for keeping freshness of the present invention is used and molded into a film or a sheet.

In the present invention, the method of molding the resin composition for maintaining freshness and molding it into a film or sheet is not particularly limited, and specifically,
For example, known methods such as extrusion molding method such as T-die method, calendar method, mold casting, and the like, in which a synthetic resin is molded into a sheet or plate shape, can be mentioned.

The thickness of the freshness-preserving film / sheet of the present invention is not particularly limited, but generally 5 to 20.
The thickness is preferably about 00 μm, especially about 10 to 500 μm. If the thickness is too thin, less than 5 μm, it may be damaged during handling or packaging of agricultural foods or cut flowers, while if it is too thick as 2000 μm. Not only is the handleability remarkably reduced, but packaging of agricultural foods and cut flowers becomes difficult, which is not desirable.

Using this freshness-preserving film sheet,
A heat-sealing or an adhesive may be used to form a bag, and the bag may contain agricultural products and cut flowers.

The freshness-keeping film / sheet of the present invention may be formed in a porous form, but this porous freshness-keeping film / sheet controls humidity in the package and causes dew condensation. The maximum pore size is 30 μm or less, especially for fruits and vegetables, which is 15 μm or less.

When the maximum pore size of the porous freshness-keeping film / sheet exceeds 30 μm, the strength of the film or sheet is remarkably reduced, and the film or sheet is partially broken during its handling. In the case of making a bag by heat sealing, an adhesive or the like, it is not preferable because the sealing strength may decrease and peeling may occur.

In this case, the maximum pore size can be measured by the Coulter Electronics Coulter
It is based on the bubble point method using a porometer.

The thickness of the porous freshness-keeping film or sheet is not particularly limited, but the moisture permeability of the film or sheet as well as the permeability of carbon dioxide and oxygen, strength, heat fusion, etc. From the viewpoints of workability, handleability, etc., the thickness is preferably 1000 μm or less, particularly about 10 to 500 μm, and further preferably 15 to 100 μm.

A known method is used to form the porous freshness-keeping film or sheet. After a film or sheet is produced from a synthetic resin, a soluble substance is extracted from the film or sheet. Or, or stretch the film or sheet, further extract the soluble substance from the stretched film or sheet,
There is no particular limitation as long as a film having a maximum pore diameter of 30 μm or less can be obtained by various methods such as perforating a film or sheet with an ultrafine needle to make it porous.

That is, the polyolefin resin is melt-stretched, then heat-treated and re-stretched. It is a method in which a soluble liquid or solid is mixed with a synthetic resin, a film is formed from this, and then the mixed liquid or solid is extracted. A film is formed from a synthetic resin, and this is perforated with an ultrafine needle to make it porous. A filler is added to a synthetic resin, a melt film is formed, and at least uniaxially stretched, or after at least uniaxially stretched, a soluble filler is extracted with water, an acid or an alkali.

Of these, particularly in the above cases, polyolefin resin is preferable as the synthetic resin because of its good productivity and low cost.

Examples of the polyolefin-based resin include homopolymers or copolymers of polyethylene, polypropylene, polybutadiene and the like, or blend polymers of these. Particularly, polypropylene (PP),
High density polyethylene (HDPE) and linear low density polyethylene (L·LDPE) are preferable from the above viewpoint.

Inorganic and organic fillers are used as the filler, and calcium carbonate is used as the inorganic filler.
Talc, clay, kaolin, silica, diatomaceous earth, magnesium carbonate, barium carbonate, magnesium sulfate, barium sulfate, calcium sulfate, aluminum hydroxide, zinc oxide, magnesium hydroxide, calcium oxide, magnesium oxide, titanium oxide, alumina, mica, asbestos Powder, glass powder, shirasu balloon, zeolite, silicate clay, etc. are used, especially calcium carbonate, talc, clay,
Silica, diatomaceous earth, barium sulfate and the like are suitable.

On the other hand, examples of the organic filler include wood powder, pulp, melamine powder, silicone resin powder and the like.

The filler has an average particle size of 10 μm or less, preferably from 0.5 to 5 μm, particularly from the viewpoint of compatibility with a synthetic resin and homogenization of a film.
Moreover, the addition amount is 10 parts with respect to 100 parts by weight of the synthetic resin.
It is preferably 0 parts by weight or less, particularly 25 to 75 parts by weight.

In this porous freshness-keeping film / sheet, the water vapor transmission rate is 100 g / m ² · 24 although the water vapor transmission rate is specified by the pore size and the degree of hydrophilicity of the film.
It is desirable to be more than hrs, 100 g / m ² · 24 hrs
If it is less than 1, the moisture permeability is too low, and depending on the type and amount of the agricultural food, the inside of the package may become over-humidified and dew condensation may be partially formed, which is not preferable. By the way, this moisture permeability is J
It is measured by IS Z-0208.

That is, in the freshness-keeping film sheet of the present invention, the oxygen concentration and the carbon dioxide gas concentration in the package can be improved by combining the porous freshness-keeping film sheet and the non-porous freshness-keeping film sheet. To identify
It is also possible to control the humidity in the package to prevent the formation of dew condensation water as much as possible, and prevent the contamination of agricultural foods and cut flowers.

When packaging the agricultural food or cut flowers using the freshness-preserving film / sheet of the present invention, when the oxygen concentration and carbon dioxide concentration in the packaging are specified, the freshness-preserving film / sheet can be used as an agricultural food or The type of cut flowers varies depending on the packaging amount, but as a result, the carbon dioxide concentration in the package (bag) is 0.5 to 10%, and the oxygen concentration is 18% or less, preferably 2 to 15%. It is a thing.

As described above, in order to control the concentration of carbon dioxide and oxygen in the freshness-keeping film / sheet, the carbon dioxide permeability is generally 3000 at a temperature of 25 ° C.
ml / m ² · 24 hrs · 1 atm or more, preferably 4000 to 20
0000 ml / m ² , 24 hrs, 1 atm, particularly preferably 50
00-100,000 ml / m ² · 24 hrs · 1 atm, oxygen permeability of 3000 ml / m ² · 24 hrs · 1 atm or more, preferably 3
^{500~250000ml / m 2 · 24hrs · 1atm} , particularly preferably it is desirable to use a film of ^{4000~20000ml / m 2 · 24hrs · 1atm} .

The synthetic resin for producing the freshness maintaining film / sheet is not particularly limited, and examples thereof include polyethylene, polypropylene, polystyrene, cellophane, polyvinyl chloride, polyester, polyamide, polypinyl alcohol, Examples thereof include vinylidene chloride and ethylene-vinyl acetate copolymer.

In this case, when the permeability of carbon dioxide and oxygen is in the range of 2000 to 15000 ml / m ² , 24 hrs, 1 atm, one film or sheet is used, and a mixed gas permeability tester GPM-200 manufactured by LYSSY is used. Is a value measured by a gas chromatograph isobaric method. or,
In the range exceeding 15000 ml / m ² , 24 hrs, 1 atm, change the thickness or superimpose two or more films, and adjust to the above range, and the transmittance of one film will be the value obtained. It is a value obtained by multiplying by the number of sheets.

However, for spinach, lettuce and the like whose deterioration is remarkably promoted by sealing, that is, when it is better to make the oxygen concentration in the package a little lower than the oxygen concentration in the air, the porous It is preferred to use a quality freshness retaining film sheet.

In the freshness-keeping film / sheet of the present invention, when a porous freshness-keeping film / sheet and a non-porous freshness-keeping film / sheet are combined, a water-absorbing agent layer is provided between the two films or sheets. Is preferably interposed.

That is, this water absorbing agent layer is
When the agricultural food and cut flowers breathe into the air, it absorbs water vapor to prevent the formation of dew condensation water and to prevent abnormal wetting of the agricultural food and cut flower surfaces. The agent layer has the ability to absorb water and release the absorbed moisture in reverse, and keeps the humidity suitable for agricultural foods and cut flowers by repeating absorption and release of water in the packaging, thereby It can prevent pain and decrease in sugar content of fruits.

Examples of the water-absorbing agent layer used in the present invention include a layer formed of a water-absorbing composition comprising the water-absorbing polymer and an inorganic water-absorbing agent. The inorganic water-absorbing agent is the water-absorbing agent layer. It is not particularly limited as long as it improves the hygroscopic ability of the adsorbent and adsorbs gas such as ethylene, but specifically, in addition to the adsorbents described above, activated carbon, zeolite-based porous material, cristobalite or silica. Examples thereof include porous materials.

Further, in this water absorbing agent layer, in order to further improve the effect of maintaining freshness, an antibacterial agent, a deodorizing agent, a fungicide and the like are contained in the water absorbing agent layer in an amount of 0.1 to 10% by weight, preferably Is desirably contained in the range of 1 to 5% by weight.

If desired, in order to improve the adhesiveness between the non-porous freshness-keeping film / sheet and the porous freshness-keeping film / sheet, the water-absorbing agent layer may be added as desired.
It is desirable to add a hydrophilic adhesive such as a polyurethane adhesive or a cellulose adhesive. in this case,
The amount of the adhesive added is preferably 250 parts by weight or less with respect to 100 parts by weight of the water-absorbent polymer.

In the present invention, it is preferable that the non-porous freshness keeping film / sheet and the porous freshness keeping film / sheet are subjected to hydrophilic treatment with a hydrophilicity-imparting agent. The hydrophilicity-imparting agent is a film. It is not particularly limited as long as it is provided on the surface of and improves the hydrophilicity of the film, and polyhydric alcohols such as glycerin, polyglycerin, ethylene glycol and polyethylene glycol, or various surfactants may be used. Can be mentioned.

As the method for hydrophilically treating the freshness-keeping film / sheet with the hydrophilicity-providing agent, a method of incorporating the hydrophilicity-providing agent into the freshness-keeping film / sheet and a freshness-keeping film / sheet are used. Examples thereof include a method of applying a hydrophilicity-imparting agent on the surface of the sheet, a method of dipping the film in an aqueous solution of the hydrophilicity-imparting agent, and a method of spraying the aqueous solution on the film.

In the freshness-preserving film / sheet of the present invention, when a water-absorbing agent layer is interposed, the water-absorbing amount and oxygen and carbon dioxide gas can be reduced by partially interposing the water-absorbing agent layer. It is preferable because the transmittance can be adjusted.

The freshness-preserving film sheet of the present invention, which is provided with a water-absorbing agent layer, of the freshness-preserving film.
The oxygen permeability of the sheet is 2000 ml / m ²
・ 24hrs ・ 1atm or more, preferably 2000-2000
00 ml / m ² , 24 hrs, 1 atm, and further 2000-150
A volume of 00 ml / m ² , 24 hrs, 1 atm is particularly desirable. The oxygen permeability was measured by the method described above.

That is, the oxygen permeability is 2000 ml / m ²
・ If it is less than 24 hrs ・ 1 atm, the carbon dioxide concentration in the packaging will increase due to the breathing of agricultural foods and cut flowers, and carbon dioxide gas obstruction may occur depending on the type of agricultural foods and cut flowers. On the other hand, 200,000 ml / m ^If it exceeds ² / 24hrs.1atm, oxygen permeability is good and the respiration of agricultural foods and cut flowers cannot be suppressed sufficiently, that is, metabolism cannot be suppressed, and the freshness of agricultural foods and cut flowers can be kept for a long time. It is not preferable because it may not be retained.

By the way, in the case where spinach or the like has an oxygen concentration substantially equal to the oxygen concentration in the air and is susceptible to the adverse effect of carbon dioxide gas when sealed, the freshness-keeping film or sheet is made porous to have an oxygen permeability. Is 20000
It may exceed 0 ml / m ² , 24 hrs, 1 atm.

No special technique or equipment is required to produce the film / sheet for keeping freshness provided with the water-absorbing agent layer of the present invention, and it can be obtained by a conventional method. Specifically, for example, a water-absorbing polymer, or a water-absorbing agent or an adhesive agent on the surface of either one of the non-porous freshness-keeping film and sheet or the porous freshness-keeping film / sheet is used. After coating the coating solution prepared by mixing the gravure method, the roll coating method, or the silk screen method, either the non-porous freshness-keeping film sheet or the porous freshness-keeping film sheet, or the other. Examples of the method include laminating films or sheets of the above.

In this case, from the viewpoint of the adhesive force between the non-porous freshness-keeping film sheet and the porous freshness-keeping film sheet, the water absorption amount, the moisture absorption capacity, the oxygen and carbon dioxide gas permeability, etc. May be provided entirely or partially on the film or sheet.

By packaging agricultural foods and cut flowers using the freshness-preserving film / sheet of the present invention, Natsume crushed stone powder adsorbs and removes produced gas such as ethylene gas and ammonia gas, and Natsume crushed stone. The far infrared rays emitted from the powder prevent the growth of microorganisms.

That is, far-infrared rays are electromagnetic waves having a peculiar wavelength region, and maintain the water retention rate in cell tissues by suppressing the growth of microorganisms and converging the plasma membrane in cell tissues of agricultural foods and cut flowers. As a result, it is possible to prevent dew condensation on the surface of fresh foods and cut flowers, and prevent spoilage and rot by sterilization and inhibition of enzyme activity. As a result, the freshness of fresh foods and cut flowers can be maintained for a long period of time.

The freshness maintaining container of the present invention is formed into a bag shape using the freshness maintaining film / sheet of the present invention. The bag can be manufactured by the method described above.

Further, in the freshness-retaining container of the present invention,
Using the resin composition for maintaining freshness of the present invention, by a known method,
It may be formed in a box shape or a bottomed cylindrical shape. With such a configuration, it can be used as a returnable box or container for keeping the freshness of agricultural products and cut flowers.

Further, in the freshness-keeping film sheet of the present invention, the water-absorbing agent layer is interposed between the non-porous freshness-keeping film sheet and the porous freshness-keeping film sheet to make it porous. While controlling the humidity in the packaging between the agricultural products and cut flowers and the water-absorbing agent layer through the freshness-preserving film / sheet to prevent the formation of dew condensation water, the non-porous freshness-preserving film / sheet and water-absorption By controlling the oxygen concentration and carbon dioxide concentration in the package, especially the oxygen concentration by the combination of the agent layers, this can control the respiration of agricultural foods and cut flowers and suppress their metabolism, resulting in the freshness of agricultural foods and cut flowers. Can be retained for a longer period of time.

As described above, since the freshness of the agricultural food or the cut flowers can be maintained for a long period of time by controlling the respiration of the agricultural food or the cut flowers to suppress the metabolism thereof, it is possible to maintain the freshness of the agricultural food or the cut flowers after harvesting. During storage and distribution of agricultural foods,
Further, as a result of further suppressing the deterioration of the freshness of the agricultural food or the like during storage at home, from this viewpoint, the freshness of the agricultural food or cut flowers can be retained for a longer period of time.

[0086]

The present invention will be described below in detail with reference to examples, but the present invention is not limited to these examples.

Production of the freshness-keeping film of the present invention Example 1 Non-porous freshness-keeping film Linear low-density polyethylene (density 0.927 g / cm ³ , MI =
2.0) 100 parts by weight of Natsume crushed stone powder (average particle size 3.
5 μm) 15 parts by weight are added, and this is melted and kneaded to form a uniform composition, and then a film is formed to give a thickness of 15 μm.
Freshness-preserving film (oxygen permeability: 18000 ml / m ²
・ 24hrs ・ 1atm, carbon dioxide permeability… 35000ml / m ²
・ 24hrs ・ 1atm) was obtained.

Each of the freshness-preserving films was lengthwise 3
It was cut into a square of 0 cm and a width of 30 cm, these cut pieces were overlapped and the three peripheral edges were heat-sealed to obtain a packaging bag with one end open.

Broccoli (500 g) was placed in this packaging bag and stored at a temperature of 5 ° C., and its change with time was observed. As a result, no abnormality such as yellowing or wilting was observed even after 8 days, but yellowing was observed in a small part on the 10th day.

Also, store the broccoli in the packaging bag, and
After a lapse of days, the produced gas such as ethylene gas and ammonia was measured by gas chromatography. As a result, ethylene gas was measured at about 1 to 2 ppm, but other produced gas such as ammonia was not confirmed.

Example 2 Porous Freshness-Preserving Film Linear low-density polyethylene (density 0.927 g / cm ³ , MI =
2.0) 100 parts by weight of Natsume crushed stone powder (average particle size 3.
(5 μm) 15 parts by weight are added, and the mixture is melted and kneaded to form a uniform composition, which is then formed into a film and then stretched to have a thickness of 30 μm and a water vapor transmission rate of 1100 g / m ² · 24 hr.
A freshness-maintaining film having a maximum pore size of 0.1 μm was obtained.

Next, in order to improve the water absorption of the freshness-keeping film, a 10% by weight isopropyl alcohol solution of a phenolic surfactant (MTN-F684, manufactured by Marubishi Yuka Co., Ltd.) was dipped on the film surface. It was applied by a method and subjected to a hydrophilic treatment. Thus, the porous freshness-keeping film of the present invention was obtained.

Each of the freshness-preserving films was lengthwise 3
It was cut into a square of 0 cm and a width of 30 cm, these cut pieces were overlapped and the three peripheral edges were heat-sealed to obtain a packaging bag with one end open.

Broccoli (500 g) was placed in this packaging bag, stored at a temperature of 5 ° C., and changes over time were observed. As a result, the same results as in Example 1 were obtained.

Also, store the broccoli in the packaging bag, and
After a lapse of days, the produced gas such as ethylene gas and ammonia was measured by gas chromatography. As a result, ethylene gas was measured at about 1 ppm, but other produced gas such as ammonia was not confirmed.

Example 3 Film for Keeping Freshness with Water-Absorbing Agent Layer Starch-polyacrylic acid graft copolymer as a water-absorbing polymer (manufactured by Sanyo Kasei Co., Ltd., Sunwet IM = 300)
Is used as a urethane adhesive and Dainippon Ink
80 parts by weight of this urethane-based adhesive and 100 parts by weight of a water-absorbent polymer were mixed at a low speed with a homomixer using (EPS-75A) manufactured by Co., Ltd., and the thickness was 15 μm.
The surface of the freshness-keeping film of 1. was coated with a gravure roll so that the amount of the water-absorbing polymer was 7.5 g / m ² to form a water-absorbing agent layer, and then the above-mentioned porous material was formed on the water-absorbing agent layer. The freshness-keeping film of 1. was laminated and adhered to obtain a freshness-keeping film having the water absorbing layer of the present invention.

The freshness keeping film had an oxygen permeability of 15,000 ml / m ² · 24 hrs · 1 atm and a carbon dioxide gas permeability of 29000 ml / m ² · 24 hrs · 1 atm.

Next, this freshness keeping film and Example 2 were used.
The porous freshness-keeping film used in
Cut into squares of 0 cm and 30 cm in width, and stack these cut pieces so that the porous freshness-keeping films overlap each other, and heat-seal the three peripheral edges to open one end. The obtained packaging bag was obtained.

Broccoli (500 g) was placed in this packaging bag and stored at a temperature of 5 ° C., and its change with time was observed. As a result, no abnormalities such as yellowing and wilting were observed even after 11 days, but yellowing was observed in a small part on the 12th day.

Also, store the broccoli in the packaging bag, and
After a lapse of days, the produced gas such as ethylene gas and ammonia was measured by gas chromatography. As a result, ethylene gas was measured at about 1 ppm, but other produced gas such as ammonia was not confirmed.

Comparative Example 1 A freshness keeping film was obtained in the same manner as in Example 1 except that zeolite (200 mesh) was used in place of the Natsume crushed stone powder.

Using this freshness-keeping film, Example 1
When a packaging bag was manufactured in the same manner as in Example 1 and the same test as in Example 1 was performed, yellowing and wilting were confirmed on a part of the broccoli after 3 days had passed.

Broccoli was placed in a packaging bag, and after 3 days, the produced gas such as ethylene gas and ammonia was measured by gas chromatography to find that ethylene gas was 11 ppm and ammonia was 11.5 ppm. Product gas was confirmed.

Example 4 78 g of spinach was washed with water, simply shaken up and down to remove water, then wrapped in the trumpet-like film with the freshness-keeping film obtained in Example 3, and stored at a temperature of 5 ° C. for 10 days. No condensed water was observed, and no abnormalities such as wilting, discoloration, and drying were observed.

Comparative Example 2 Using the freshness-keeping film obtained in Comparative Example 1, the same test as in Example 4 was carried out. After 2 days of storage, dew condensation water was generated at a large number of places on the inner surface of the packaging material. It was confirmed that the product value was remarkably reduced due to partial wilting and color change.

Example 5 500 g of ginseng was washed with water, simply shaken up and down to drain, and then sealed in a 2000 ml packaging bag formed of the freshness-keeping film obtained in Example 3, and kept at a temperature of 20 ° C. for 1 month. When stored for a while, no dew condensation water was observed, and no abnormalities such as color change and drying were observed.

Comparative Example 3 Using the freshness-keeping film obtained in Comparative Example 1, the same test as in Example 5 was carried out. After 15 days of storage, dew condensation water was generated at many places on the inner surface of the packaging bag. It was confirmed that a part of the carrot had a mold-like part on its neck, and the color of the carrot partially changed, resulting in a significant decrease in the commercial value.

Example 6 After harvesting 50 chrysanthemums, the freshness-keeping film obtained in Example 3 was wrapped in a trumpet shape and stored at a temperature of 10 ° C. for 10 days. No dew condensation was observed, and , Wilt,
No abnormalities such as color change and drying were observed.

Comparative Example 4 Using the freshness-keeping film obtained in Comparative Example 1, the same test as in Example 6 was carried out. After 3 days of storage, dew condensation water was generated at many places on the inner surface of the packaging material. It was confirmed that the product value was remarkably reduced due to partial wilting and color change drying.

From the above results, in the freshness-keeping film of the present invention, and by using the freshness-keeping film / sheet of the present invention to package agricultural foods, cut flowers, etc. Adsorption and removal of produced gas such as ammonia gas, and far infrared rays emitted from Natsume crushed stone powder prevent the growth of microorganisms.

That is, far-infrared rays are electromagnetic waves having a peculiar wavelength region, and maintain the water retention rate in cell tissues by suppressing the growth of microorganisms and converging the plasma membrane in cell tissues of agricultural foods and cut flowers. As a result, it is possible to prevent dew condensation on the surface of fresh foods and cut flowers, and prevent spoilage and rot by sterilization and inhibition of enzyme activity. As a result, the freshness of fresh foods and cut flowers can be maintained for a long period of time.

Further, in the film for keeping freshness of the present invention, the humidity in the package is kept constant, and the oxygen concentration and the carbon dioxide concentration are controlled to suppress the respiration of agricultural foods and cut flowers. It is recognized that the freshness of cut flowers and cut flowers can be preserved for a long period of time.

[0113]

EFFECTS OF THE INVENTION The freshness-preserving film / sheet of the present invention is obtained by adding Natsume crushed stone powder to a synthetic resin to adsorb ethylene gas by this Natsume crushed stone powder and further offensive odor substances such as ammonia, and also Natsume crushed stone powder. The far-infrared rays emitted from the glass have the effect of maintaining the freshness of agricultural foods such as vegetables and fruits or cut flowers for a long period of time.

That is, the freshness-preserving film / sheet of the present invention effectively adsorbs and removes ethylene gas generated by respiration of agricultural foods and cut flowers, and suppresses the bactericidal effect and the growth of microorganisms by irradiation with far infrared rays. Therefore, the freshness of agricultural products and cut flowers can be maintained for a long period of time.

Since the freshness-preserving film / sheet of the present invention is inexpensive and easy to handle, it is further packaged with the film / sheet after harvesting agricultural foods or cut flowers during storage or during their distribution period. It has the effect of suppressing the deterioration of freshness of agricultural products and cut flowers stored at home.

Further, in the freshness-keeping film sheet of the present invention, when a water-absorbing agent layer is interposed between the freshness-keeping film sheet of the present invention and the porous freshness-keeping film sheet of the present invention, dew condensation occurs. While preventing the formation of water, the combination controls the oxygen concentration and carbon dioxide concentration in the package, especially the oxygen concentration, which can control the respiration of agricultural foods and cut flowers to suppress its metabolism. As a result of quickly controlling the humidity inside, the freshness of agricultural foods and cut flowers can be maintained for a longer period of time.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location C09C 3/00 PBP C09C 3/00 PBP

Claims (11)

[Claims] 1. A resin composition for maintaining freshness, characterized in that 2 to 300 parts by weight of Natsume crushed stone powder are mixed with 100 parts by weight of synthetic resin. 2. The resin composition for keeping freshness according to claim 1, wherein 0.01 to 10 parts by weight of a coupling agent is added to 100 parts by weight of Natsume crushed stone powder. 3. The resin composition for maintaining freshness according to claim 2, wherein the Natsume crushed stone powder is previously coated with a coupling agent. 4. Otani stone, zeolite, cristobalite, clinoptilolite, calcium silicate, acid clay, activated clay, bentonite, diatomaceous earth, sulfur stone, perlite, activated alumina or talc per 100 parts by weight of Natsume crushed stone powder. At least one selected adsorbent 1-30
A resin composition for maintaining freshness, which is blended with parts by weight. 5. The resin composition for maintaining freshness according to claim 4, wherein the adsorbent is previously coated with a coupling agent. 6. A freshness-keeping film or sheet formed by using the resin composition for freshness-keeping according to claim 1 to be formed into a film or a sheet. 7. The freshness-keeping film according to claim 6,
A freshness-preserving film with a porous sheet
Sheet. 8. A freshness-retaining material in which a water-absorbing agent layer is interposed between the non-porous freshness-keeping film sheet according to claim 6 and the porous freshness-keeping film sheet according to claim 7. Film sheet. 9. A freshness-keeping container formed in a bag shape using the freshness-keeping film sheet according to any one of claims 6 to 8. 10. A container for freshness-keeping, which is formed in a box shape by using the resin composition for freshness-keeping according to any one of claims 1 to 5. 11. A freshness-retaining container formed by using the resin composition for freshness-retention according to any one of claims 1 to 5 and molding it into a bottomed tubular shape.