JPH044841A - Wrapping material for keeping freshness of vegetable and fruit, wrapping method and wrapped body - Google Patents

Abstract

PURPOSE:To improve the subject freshness effect with keeping an equilibrium state and suppressing respiration by using a synthetic resin film comprising a copolymer of ethylene and alpha-olefin and having specific values of a permeating coefficient of carbon dioxide gas and a permeating coefficient of moisture vapor. CONSTITUTION:For instance, the aimed wrapping material is composed of a synthetic resin film comprising a copolymer of preferably ethylene and 3-12C alpha-olefin (e.g., ethylene-butene-1 copolymer) and low-density polyethylene and preferably having 20 - 40 mum thickness, >=15 X 10<-10> cm<3> (STP) cm/(cm<2> .s . cmHg) permeating coefficient of carbon dioxide gas: PCO2 at 27 deg.C, >=4.2 ratio of permeating coefficient of carbon dioxide gas: PCO2 to permeating coefficient of oxygen: PO2 and 80 X 10<-9> cm<3> (STP) cm/(cm<2> . s . cmHg). Besides, vegetables and fruits are wrapped with the wrapping material to obtain a wrapped body to keep freshness.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a packaging method, packaging material, and packaging body for preserving the freshness of fruits and vegetables using special packaging materials.

[Prior Art] Various attempts have been made to maintain the freshness of fruits and vegetables. Various methods have been proposed, including using oxygen agents to suppress respiration and adsorbing ethylene gas to prevent overripening.

For example, Japanese Patent Publication No. 38-2757 describes the use of high-pressure polyethylene film to package and refrigerate fruits and vegetables to prevent moisture evaporation and overripening.

Furthermore, Japanese Patent Application Laid-Open No. 61-216640 describes that fruits and vegetables can be stored by packaging them using a synthetic resin film with a permeability ratio of carbon dioxide to oxygen (CO2102) of 3 to 4 to control respiration. ing. However, even when such a film is used, a sufficient effect of preserving the freshness of fruits and vegetables cannot be obtained.

[Problem to be solved by the invention] Conventional techniques have not been able to satisfactorily solve the problem of preserving freshness because the fundamental problem of why fruits and vegetables lose their freshness has not been sufficiently elucidated. .

According to the research conducted by the present inventors, fruits and vegetables exhibit biological reactions even during storage, including respiration and the actions of plant hormones and enzymes. Therefore, for example, if ethylene gas is present in the storage atmosphere, aging hormones are actively secreted and aging is accelerated. In addition, the composition of the storage atmosphere changes due to the respiration of fruits and vegetables, and when there is too little oxygen and too much carbon dioxide gas, alcohol fermentation progresses, producing aldehydes and ammonia, and the freshness decreases. If there is too much oxygen, respiration will be intense and ripening will proceed.To maintain the freshness of fruits and vegetables, it is necessary to control not only the amount of carbon dioxide gas but also the amount of oxygen to an appropriate value.

Most fruits and vegetables have a high water content of 80 to 95%, and when they are left in low humidity, water evaporates rapidly from tissues such as the pericarp and leaves, and this water loss quickly occurs. It causes wilting and reduces freshness.Usually, when more than 5% of moisture is lost, some change in appearance occurs.

The present inventors focused on the physiology of such plants and conducted research on adjusting the gas composition of the storage atmosphere.

As a result, in order to maintain the freshness of fruits and vegetables, it is necessary to (1) suppress moisture transpiration, (2) adjust the amount of oxygen in the storage atmosphere, and keep it in the range of 1 to 16%, preferably 2 to 12%. (2) It is necessary to minimize the amount of carbon dioxide gas present in the storage atmosphere, within the range of 0 to 20%, preferably 2 to 15%.

[Means for Solving the Problems] The composition of the storage atmosphere changes due to the respiration of fruits and vegetables, and the composition moves in the direction of maintaining an equilibrium state, thereby maintaining an equilibrium state. If this equilibrium state is such that there is no anaerobic respiration, the secretion of aging hormones is low, there is no acceleration of aging, and there is respiration, but the amount of respiration is small, the freshness of fruits and vegetables will be maintained for a long time. In other words, fruits and vegetables are put into a dormant state by releasing as much carbon dioxide gas generated by breathing the storage atmosphere to the outside, and by introducing an appropriate amount of oxygen into the storage atmosphere from the outside to balance the storage atmosphere within the above range. This maintains freshness.

As a result of various studies to create such a state, the present inventors obtained new knowledge that it is not possible to put fruits and vegetables into a dormant state unless the packaging material is improved.The present inventors improved the packaging material and developed the present invention. completed.

The present invention provides r1. Carbon dioxide permeability coefficient Pco2 at 27°C
However, 15 X 10-10■3 (STP)■/(■2S1
country Hg) and above, the ratio of carbon dioxide permeability coefficient Pco2 to oxygen permeability coefficient Po2 is 4.2 or more, and water vapor permeability coefficient PH2
0 is 240X10-'co' (STP) cm/ (cm
2S, ■Hg) A packaging material for preserving the freshness of fruits and vegetables, consisting of the following synthetic resin film.

2. Synthetic resin film contains ethylene and carbon number 3 to 12
The fruit and vegetable freshness-keeping packaging material according to claim 1, characterized in that it is composed of a copolymer of α-olefin.

3. Synthetic resin film contains ethylene and carbon number 3 to 12
A blend of two or more copolymers of α-olefins or one or more copolymers of ethylene and α-olefins having 3 to 12 carbon atoms and low-density polyethylene. The fruit and vegetable freshness-keeping packaging material according to claim 1, characterized in that:

4. Copolymers of edil/n and α-olnofine having 3 to 12 carbon atoms are ethyl/n-butene-1 copolymers, ethylene-hexene-1 copolymers, ethyl/n-methylbentene-1 copolymers, etc. The packaging material for preserving the freshness of fruits and vegetables according to any one of claims 1 to 3, characterized in that the packaging material is one or more selected from a polymer and an ethylene-octene 1 copolymer.

5. The fruit and vegetable freshness-preserving packaging material according to any one of claims 1 to 4, wherein the copolymer of ethyl/one and α-ol/fin having 3 to 12 carbon atoms is ultra-low density polyethylene. .

6. Carbon dioxide permeability coefficient Pc of fruits and vegetables at 27°C
o2 is 15 x 10-”13” (STP) a! l/
(on2s, aIIIHg) and above, the ratio of carbon dioxide permeability coefficient Pco2 to oxygen permeability coefficient PO2 is 4.2 or more, and water vapor permeability coefficient PH2
0 is 240X10-'cz' (STP)■/(■2S,■
Hg) Packed with the following packaging material made of synthetic resin film, carbon dioxide gas is released from the inside of the package to the outside to suppress anaerobic respiration of fruits and vegetables, and - control the amount of aerobic permeation into the inside of the package. A method for preserving the freshness of fruits and vegetables by suppressing breathing.

7. Synthetic resin film contains ethylene and carbon number 3-12
7. The freshness-keeping packaging method for fruits and vegetables according to claim 6, characterized in that the method is made of a copolymer of α-olefin.

8. The synthetic resin film has ethyl chloride and 3 to 1 carbon atoms.
Consisting of a blend of two or more copolymers of α-olefins selected from 2 or a blend of one or more copolymers of ethylene and α-olefins having 3 to 12 carbon atoms and low-density polyethylene. 7. The freshness-keeping packaging method for fruits and vegetables according to claim 6.

9. Copolymers of ethylene and α-olefins having 3 to 12 carbon atoms are ethylene-butene-1 copolymers, ethylene-hexene-1 copolymers, ethylene-methylbentene-1 copolymers, etc.
The freshness-keeping packaging method for fruits and vegetables according to any one of claims 6 to 8, characterized in that the packaging method is one or more selected from a copolymer and an ethylene-octene-1 copolymer.

10. The freshness-keeping packaging method for fruits and vegetables according to claim 6t or 9, wherein the copolymer of ethylene and α-olefin having 3 to 12 carbon atoms is ultra-low density polyethylene.

11. Carbon dioxide permeability coefficient Pc of fruits and vegetables at 27°C
o2 is 15 x 10-”am’ (STP) txr/
(ca?s, czHg) and above, the ratio of carbon dioxide permeability coefficient Pco2 to oxygen permeability coefficient PO2 is 4.2 or more, and water vapor permeability coefficient PH2,0 is 240 x 10-5■3 (STP)■/ ((to) 2
S, ■Hg) or less i! 1. A freshness-preserving package for fruits and vegetables, characterized in that it is packaged with a packaging material to release carbon dioxide gas to the outside to suppress anaerobic respiration, and to suppress respiration by controlling the amount of permeation of aerobic gas into the interior.

12. Synthetic resin film contains ethylene and 3 to 1 carbon atoms
12. The fruit and vegetable freshness-keeping package according to claim 11, characterized in that the package is made of a copolymer of α-olefin No. 2.

13. Synthetic resin film contains ethylene and 3 to 1 carbon atoms
Consisting of a blend of two or more copolymers of α-olefins selected from 2 or a blend of one or more copolymers of ethylene and α-olefins having 3 to 12 carbon atoms and low-density polyethylene. 12. The fruit and vegetable freshness-keeping package according to claim 11.

14. Copolymers of ethylene and α-olefins having 3 to 12 carbon atoms are ethylene-butene-1 copolymers, ethylene-butene-1 copolymers,
Hexene-1 copolymer, ethylene-methylpentene-1
Claim 11 characterized in that it is one or more selected from a copolymer and an ethylene-octene-1 copolymer.
The fruit and vegetable freshness-keeping package described in any one of items 1 to 13.

15. The fruit and vegetable freshness-keeping package according to any one of claims 11 to 14, wherein the copolymer of ethylene and an α-olefin having 3 to 12 carbon atoms is ultra-low density polyethylene.

First, the carbon dioxide permeability coefficient Pco2 of the film is 15x
10-1OQllS(STP) cs/ (an2.
s, cxnHg) Otherwise, no matter how you change other conditions, the storage atmosphere will not be satisfactory.

Next, it is necessary that the ratio between the carbon dioxide gas permeability coefficient Pco2 and the oxygen permeability coefficient PO2 is 4.2 or more.

If it is less than 4.2, the concentration of carbon dioxide and oxygen cannot be sufficiently controlled, and fruits and vegetables cannot be kept in a dormant state.

In addition, water vapor permeability "Ir (fh RP 82.0 is 24
0 X 10-9>” (STP) al!/ (c
m2, s, amHg) or less, a large amount of water will be released to the outside of the packaging material, and the fruits and vegetables inside the packaging will undergo rapid water evaporation, causing wilting, and thus the freshness of the fruits and vegetables cannot be maintained.

Therefore, in the present invention, all of the above conditions are combined with each other to produce a synergistic effect.

Next, the synthetic resin film used in the present invention will be explained.

A synthetic resin film that satisfies the requirements for transmittance characteristics of the present invention can be formed from a single synthetic resin, but it is also possible to form a synthetic resin film from a plurality of synthetic resins because it is necessary to independently satisfy the requirements with different characteristics described above. Typical examples of such synthetic resins include ethylene and α-carbon atoms having 3 to 12 carbon atoms.
Olefin copolymers, such as ethylene-butene-1 copolymer, ethylene-hexene-1 copolymer, ethylene-4
Examples include methylpentene-1 copolymer and ethylene-octene-1 copolymer, and it is preferable to use a blend of at least two or more selected from these resins. Blends of these ethylenes, α-olefin copolymers having 3 to 12 carbon atoms, and low density polyethylene can also be used. In order to obtain a particularly high carbon dioxide permeability coefficient, low-density ethylene-α-olefin copolymers with a relatively high copolymerization ratio of α-olefins or so-called ultra-low density ethylene-α copolymers with a high copolymerization ratio of α-olefins are recommended. - It is preferable to use an olefin copolymer as the main component, and in order to obtain a high selective permeation ratio,
At least two types of resins composed of different monomers from the above resin group, such as low density polyethylene and ethylene-hexene-1 copolymer, ethylene-butene-1 copolymer, etc.
It is preferable to select and use a combination such as 1 copolymer and ethylene-hexene-1 copolymer.

In addition, as another method for obtaining a synthetic resin film that satisfies the requirements for permeation properties of the present invention, an ethylene-vinyl acetate copolymer ( EVA),
Ethylene copolymers such as ethylene-acrylic acid copolymers, ethylene-methyl methacrylate copolymers, ethylene or α-olefin-propylene-nonconjugated genter polymers, or styrene/butadiene block copolymers, styrene/isoprene block copolymers It is also possible to use a blend of resins such as hydrogenated polymers.
When these resins are used as a single resin as shown in the example of fIi, it is difficult to satisfy all the permeability requirements of the present invention, so the ratio of 90:10 to 90:10 to the above base polymer is difficult. It is necessary to use a blend ratio of 50:50.

The detailed reason why blending resins with different repeating units increases the permselectivity ratio between carbon dioxide and oxygen is unknown, but it is probably because molecular chains with different molecular mobility exist at different concentrations. It is presumed that this is because there is a region, and the permeability of both gases in that region changes depending on the concentration of molecule n.

These resin films contain antioxidants or heat stabilizers such as phenolic, W'IK yellow, organic nitrogen, and organic phosphorus, as well as metallurgicals and other fatty acids, according to known formulations. Lubricants such as esters and other fatty acid derivatives, antifogging agents, antistatic agents, calcium carbonate, white carbon,
Compounding agents such as titanium white, magnesium carbonate, magnesium silicate, carbon black, various clays, inorganic fillers such as natural or synthetic zeolites, and other coloring agents can be blended in known blending ratios.

The thickness of these resin films should be determined appropriately depending on the type of resin used and its physical strength, as well as the relationship between the content and surface area of the bag used, and in some cases, the type of fruits and vegetables to be packaged, storage temperature, etc. Generally, it is appropriate to set the thickness to about 15 to 50 μm, preferably 20 to 40 μm.

Melt index (M
There is no particular limit to I), but for example, the MI value is 0.1~
It is preferable to use one with a rate of about 10 g/10 minutes (according to JISK6760).

The resin film of the present invention can be formed using a method known per se, such as an inflation method or a T-die method, and in the case of a bag with a relatively large capacity, the former method is used, and the pillow-type film described in a later example is used. The latter method is advantageous in the case of packaging. Furthermore, as long as the requirements for permeation characteristics of the present invention are satisfied, it can be used in the form of coextrusion with other resins or laminates such as resin films and sheets.

The packaging material according to the present invention can be applied to fruits and vegetables in various forms, and there are no particular limitations on the form of use. 1. For example, when used in the form of a bag, the bottom of a tube-shaped film is sealed, or a sheet-shaped film is sealed on three sides, and fruits and vegetables are filled in the bag, or the back and bottom seals are used. Place the fruits and vegetables in the sealed bag and seal the entrance.

As a sealing method, a sealing method known per se, such as an impulse seal, a high frequency seal, an ultrasonic seal, etc., can be used. Also, in the case of bags, tape the opening.
It is also possible to seal with a rubber band, wire ribbon, etc. so as to maintain a substantially sealed state. Furthermore, the opening of a large tray made of polystyrene, polyvinyl chloride, or the like can be heat-sealed with this film.

When using the packaging material according to the invention, it is possible to use in conjunction with means known per se that are effective for preserving the freshness of fruits and vegetables.

For example, gas adsorbents are used to prevent gases such as ethylene and aldehydes from fruits and vegetables, and humectants and moisture absorbers are used to control moisture in bags.
Alternatively, oxygen scavengers, carbon dioxide removers, and the like may be even more effective in preserving freshness.

These adjuvants are usually used in the form of a separate bag inside the packaging material of the present invention, but in some cases, it is also effective to coat the packaging material of the present invention.

[Function] In order to explain the action of the present invention in an easy-to-understand manner, fruits and vegetables are shown below. Yes, asparagus, broccoli (V) peach, (Vl) strawberry,
Bamboo shoots are classified into 6 groups, and the storage requirements are a: cold storage, b = moisturizing, C: atmosphere, d: ethylene removal,
e: Antibacterial and compared. As a result, it was found that in group <I), abc had a large effect, and b had a particularly strong influence.

In group (I[), ac has a large effect and d also has an influence, but it was found that the influence of C is particularly strong.

It was found that aC had a large effect on group <m>.

It was found that group (TV) was strongly influenced by ab.

It was found that croup (V) is strongly affected by a and also by d.

It was found that group (V[) was affected by ab and strongly influenced by e.

As described above, the fresh preservation of fruits and vegetables is influenced by the preservation requirements of a%e, and among these, it is understood that a: cold storage and C: atmosphere have a large influence.

A brief explanation will be given of the movement of gas generated between the atmosphere inside the package and the outside air during the storage of fruits and vegetables.

Carbon dioxide gas C○2 generated by the respiration of fruits and vegetables passes through the packaging film and is released into the outside air. On the other hand, oxygen O2 consumed by the respiration of fruits and vegetables passes through the packaging film from the outside air and enters the package. Here, the key to creating an atmosphere that keeps fruits and vegetables in a dormant state is to reduce the amount of carbon dioxide gas in the package as much as possible by dissipating it into the outside air, and by controlling the amount of oxygen that enters. It is understood that it is important to control the amount of breathing to the minimum necessary.

Furthermore, another effect of using the packaging material of the present invention is that the packaging material of the present invention has high gas permeability and releases ethylene gas generated by fruits and vegetables to the outside very efficiently. It suppresses the increase in waste concentration and has the effect of preventing the aging of fruits and vegetables.

Detailed effects are shown in the Examples section along with comparative tests, but
By adjusting the atmosphere of the present invention, compared to conventional packaging,
It was observed that the fresh shelf life was extended by more than 50%.

In the packaging material of the present invention, the carbon dioxide gas permeability coefficient Pco2, the ratio of the carbon dioxide permeability coefficient Pco2 to the oxygen permeability coefficient P02, and the water vapor permeability coefficient PH2,0 must be within a specific range of numerical values. A typical film used in the present invention, which will be explained in detail in the following Examples section for ease of understanding, is formed from a composition that is a blend of an ethylene low density polymer and an ethylene-α-olefin copolymer. The following Table A clearly shows the performance of this synthetic resin film along with other conventionally used packaging materials, showing that this film satisfies the above conditions.

(Left below) It is clear that in the past, packaging materials that met the requirements for fresh preservation of fruits and vegetables were not used, and as a result, it was not possible to preserve fresh fruits and vegetables satisfactorily. be understood.

[Example code] Next, examples will be given and concretely explained in comparison with comparative examples.

First, I will explain transparency.

Evaluation of gas and water vapor permeation characteristics at 27°C of various films used in the following examples were evaluated by the method described below.

For gas permeability measurement, we used a mixed gas permeability measuring device (LYSSY GPE-20) that uses a commercially available gas chromatography as a detector.
0) was used. A mixture of carbon dioxide and air with a volume ratio of 1:4 was flowed to the upstream I side of the film at normal pressure.
Using helium gas as a carrier gas on the dOWnStreal side, the gas composition on the downstream side is measured moment by moment, the count number of each gas is corrected using a calibration curve created, the permeation amount at each time is determined, and the Find the slope using the least squares method from the point, and taking into account the thickness of the film used and the effective area of the transmission cell, calculate the transmission coefficient Pco2, PO2■3 (STP) ctn /
((m 2 , S , anH(]) was calculated.

Also, from these two values, the permeability coefficient ratio P c O2/P
.

I asked for 2. All measurements were performed while keeping the permeation cell and chamber at a constant temperature of 27°C.

A commercially available water vapor permeability tester (LYSSY18
0-4000 type) and 25μ as a standard sample.
A biaxially stretched polyethylene terephthalate film having a diameter of 1.5 mm was used after its permeability was measured in advance by the cup method. According to this method, the water vapor permeability is tr/<rrr・da
It is determined in units of y). Therefore, from this measurement value, we will use the film thickness and water vapor pressure at 27°C (2,6
7■HQ) using ■3 (STP)■/(dos・
■Converted to the unit of H(]), it was used as an index of the water vapor permeability of the film.For example, the permeability is 148 at a thickness of 30 μm.
In the case of a film of g/ (rrr-daV), the conversion is 240X10-'am3(STP)■/(-・S-■
This is the transmission number of H(]).

5? Case of refusal 1.

Flat bags with dimensions of 25 x 20 x 2 were made by heat sealing from films having various permeability and compositions and film thicknesses shown in Table 1. Approximately 1 kg of freshly harvested kabosu (average number: 15) was placed in each bag, and the openings were sealed by heat sealing. These packaging bags are kept at room temperature (2
5±2°C) and a relative humidity of 65%.
Changes in the appearance of the kabosu, such as changes in the pericarp, browning of the pericarp, softening, mold growth, and wilting (weight loss), were observed. Furthermore, for the bags to which a stopcock for collecting gas inside the bag was attached in advance, the gas composition (CO2, 02) inside the bag was measured by gas chromatography.

Approximately 150 kabosu (kabosu) in 10 bags of each aging group were inspected for each test No. 1, 1 month and 2 months after storage, and the waste composition was determined as the average value of 3 bags. shows the number of non-defective products determined by visual inspection, details of defects, number of defects, and gas composition.

According to the results of storage tests, when unwrapped, the initial green color of kabosu and the firmness of the peel changed to partial yellowing of the peel and an unmarketable appearance after about two weeks, whereas when wrapped with film, In some cases, depending on the transmission characteristics of the film, each exhibited a characteristic storage stability and appeared as a change in appearance. In other words, when the carbon dioxide gas permeability coefficient is smaller than the range of the present invention (Test Nos. 31-6 to 9), the concentration of carbon dioxide in the bag increases significantly, although there are some differences in each case. Many defects occur due to browning of the pericarp due to gas disturbance. In addition, in this case, the oxygen concentration inside the bag was at an extremely low level, resulting in an alcohol odor due to anaerobic respiration, and the unique scent of kabosu was lost. In addition, in this case, the lower the carbon dioxide permeability coefficient or the lower the permeability coefficient ratio, the worse the storage stability tended to be. On the other hand, when the carbon dioxide permeability coefficient is extremely large, for example in test No. 1-5, the permeability coefficient ratio is small because the film is porous.
While the carbon dioxide concentration inside the bag can be maintained at a fixed position, the oxygen concentration inside the bag is not much different from the outside air. Therefore, there is almost no respiratory suppressing effect, and aging progresses quickly. ,t,
Even when the film is not porous and the permeability 31jJ coefficient ratio is smaller than the range of the present invention (Test No. 1-4), the storage period is slightly extended, but it is still insufficient. Furthermore,
In the case of rubber-based film, it has a significantly high water vapor permeability corresponding to carbon dioxide gas permeability, so it passed test No. 1-3.
In addition to yellowing of the pericarp due to insufficient respiratory suppression,
Many defects due to wilting due to excessive water transpiration do not occur.

When using at least two or more ethylene and α-olefin copolymers shown in Table 1 as a film material that satisfies all requirements for permeability properties of the present invention (Test No. 1-1,
1-2, 1-10 to 1-13) have a moderate oxygen permeability in addition to a somewhat high carbon dioxide permeability, so they have a good respiratory suppressing effect and there is no yellowing or browning of the pericarp. Furthermore, since the water vapor permeability was relatively low, wilting due to water evaporation was completely prevented, and it was possible to maintain a fresh green color for a long period of time.

Example 2゜Dimension 30 from a film consisting of each composition and film thickness shown in Table 2
X20■? A flat bag was made by heat sealing. Approximately 1 kg of green plums (average number of 235 pieces), which had been pre-cooled by leaving them in a pre-cooling cabinet at 5°C for 8 hours after harvest, were placed in these bags, and the openings were tied and sealed with a rubber band.

These packaging bags are kept at room temperature (25±2℃), relative temperature 65%
The green plums were stored in an atmosphere for a period of time, and changes in the appearance of the green plums, such as yellowing of the pericarp, browning of the pericarp, appearance of spots, softening, mold growth, and depressions, were observed. In addition, the gas composition inside the bag was appropriately evaluated as in the previous example.

Approximately 350 green plums (approximately 350 green plums) in 10 bags of each aged group for each test No. 3 were visually inspected 4 days and 1 week after storage, and the gas composition was determined as the average value of the three bags.

According to the results of storage tests, in the case of unpackaged green plums, the original green color, skin tension, and pulp hardness were lost in about 3 days, yellowing and softening occurred, and the marketability was significantly reduced. On the other hand, in the case of film packaging, as described below, the film according to the present invention is used, which has a high selective permselectivity ratio to ensure high carbon dioxide gas permeability and appropriate oxygen permeability, and keeps water vapor permeability below a certain level. This showed good storage stability. In other words, general low-density polyethylene (Test No.
, 2-1), because the carbon dioxide gas permeability coefficient or permeation coefficient ratio is small, especially in the case of green plums, which have remarkable respiration at room temperature, the carbon dioxide concentration in the bag is extremely high and the oxygen concentration is almost zero, resulting in an airless state. It became respirable, and some browning occurred after 4 days of storage, and browning, softening, and an alcohol odor were observed almost entirely on the 7th day of storage. In contrast, by blending low-density polyethylene with a relatively low-density ethylene-butene-1 copolymer above a certain level, a permeability coefficient ratio corresponding to high carbon dioxide permeability and appropriate oxygen permeability can be obtained. (Test No. 2)
-3), when ethylene-hexene-1 copolymer is used as a base polymer, it shows relatively high carbon dioxide gas permeability, but with a single composition, the permeability coefficient ratio is small, and therefore the oxygen permeability coefficient is large, making it difficult to breathe. Since inhibition was incomplete, storage stability was also somewhat insufficient (Test No. 2-4).

However, by blending a relatively low-density ethylene-octene-1 copolymer with this base polymer, the carbon dioxide gas permeability coefficient becomes even higher, and the permeability coefficient ratio also increases, resulting in a loss of dirt inside the bag. The concentration was maintained at an appropriate composition and showed good storage stability (Test No. 2-5)
~2-7.1゜ (blank below) Example 3゜ Approximately 140 g (7 to 8 mushrooms) of freshly harvested shiitake mushrooms were arranged face up on a commercially available tray made of foamed resin with dimensions of 10 x 15 x 2. So-called pillow-type packaging was carried out using a heat sealing method using films having the compositions and film thicknesses shown in Table 3. The surface area of this package, excluding the seal, was approximately 13 x 20 x 2. The changes in the appearance of the caps, such as blackening, dryness, mold growth, and softening, were observed. In addition, the gas composition inside the bag was appropriately evaluated as in the previous example.

Approximately 74 to 80 raw shiitake mushrooms (total number of 74 to 80 fresh shiitake mushrooms, 10 bags for each aging group for each test No. 0) were visually inspected on the 3rd and 5th day after storage, and the gas composition was the average value of the 3 bags. I asked for it as.

According to the results of the storage test, in the case of unpackaged products, the appearance changed due to drying after about 1.5 days, and in particular, the nail parts became hard, clearly indicating a decline in marketability.

On the other hand, in the case of film packaging, the use of the film of the present invention, which has a high permselectivity ratio to ensure high carbon dioxide gas permeability and appropriate oxygen permeability, and suppresses water vapor permeability below a certain level, can achieve good results. It showed good shelf life. In other words, in the case of ethylene-vinyl acetate copolymer, when the content of vinyl acetate is low (Test No. 3-1), it exhibits permeability similar to that of low-density polyethylene, has a low carbon dioxide permeability coefficient, and is highly selective. Because the permeability coefficient ratio was low, the inside of the bag had a significantly high concentration of carbon dioxide, was accompanied by an alcohol odor due to anaerobic respiration, and tended to lose its tension and become soft. When the vinyl acetate content was 10% (Test No. 3-2), although the storage stability was somewhat improved compared to the previous example, there was still a slight lack of oxygen, and some softened with a slight alcohol odor. Furthermore, when the vinyl acetate content is high (Test No. 3-3), the carbon dioxide gas permeability coefficient and permselectivity ratio are values suitable for maintaining the appropriate gas composition within the bag.
-The water vapor permeability coefficient becomes significantly large.

As a result, fresh shiitake mushrooms no longer softened, but many of them tended to dry out, and many of them became hard after 5 days of storage. In addition, when the vinyl acetate content is 20% (Test No.
, 3-4), since the water vapor permeability coefficient becomes even larger,
Furthermore, there is a tendency for changes in appearance to occur more often as a result of drying. In addition, during the drying process, blackening and mold growth were observed on the umbrellas. In other words, it has not been possible to obtain an ethylene-vinyl acetate copolymer film that satisfies all requirements for permeation characteristics suitable for storage stability.

On the other hand, if an ethylene-hexene-1 copolymer is used as a base polymer and then a relatively low-density ethylene-octene-1 copolymer (Test No. 013-5) or an ethylene-vinyl acetate copolymer (vinyl acetate-containing amount 10%)
(Test No. 3-6), it satisfies all the requirements for permeation properties, makes it possible to maintain a good gas composition in the bag, and shows good storage stability.

(Left below) Example 4 Commercially available dimensions 6x12aII! Place 2 kabosu (approximately 130 to 140 g) immediately after harvest on each tray made of foamed resin.
), and using films having the respective compositions and film thicknesses shown in Table 4, low packaging was performed using the heat sealing method in the same manner as in Example 3 above.

The surface area of this package excluding the seal is approximately 8 x 16 x
It was 2dl. These tray packages are stored at low temperature (5±1℃
), the kabosu was stored in an atmosphere of 85% relative humidity over time, and changes in the appearance of the kabosu were observed, while the gas composition of the tray was appropriately evaluated as in the previous example.

For each test No. 9, 50 bags of each aged group, 100 kabosu were examined for appearance 3 months and 5 months after storage, and the gas composition was determined as an average value of 3@.

According to the results of the storage test, in the case of unpackaged kabosu, after about 1.5 months of storage, there was a lot of partial yellowing of the peel of the kabosu, and wilting due to dryness due to water evaporation, whereas Table 4
When the packaging film of the present invention shown in Figure 1 is used, the selective permselectivity ratio for carbon dioxide permeability and moderate oxygen permeability is kept to a certain level, and the water vapor permeability is also suppressed to a low level, so the tray The gas composition inside the packaging was well maintained and water evaporation was suppressed, resulting in almost perfect shelf life in the 3 month period, and although there was a slight difference due to the permeability of the film in the 5 month period. It also showed satisfactory storage stability. In particular, in this case, it is better to use a copolymer of ethylene and α-olefin as the base polymer than low-density polyethylene, and to use a styrene-butadiene or styrene-isoprene block copolymer as a blend resin to increase the permselectivity ratio. The use of a copolymer of ethylene and α-olefin in which the base polymer and comonomer were different showed somewhat better storage stability than the hydrogenated product of the polymer.

(Hereinafter in the margin) [Effects] As mentioned above, the present invention uses a packaging material with special performance to achieve an extremely excellent effect of preserving the freshness of fruits and vegetables, which was previously impossible to achieve.

Wataru Fukasawa, Commissioner of the Japan Patent Office1, Indication of the case, Patent Application No. 103131 of 1990,2, Name of the invention, Packaging material for preserving the freshness of fruits and vegetables, packaging method, and packaging body3, Person making the amendment, Relationship with the case, Address of the patent applicant. 3-13-17 Nagasaki, Toshima-ku, Tokyo Name
Yasushi Kuwahara 4, Agent 107 (Telephone 3582-7211)
Address: 4-13-5-5 Akasaka, Minato-ku, Tokyo, Specification subject to amendment 6, Contents of amendment (1) The scope of claims is amended as shown in the attached sheet.

(2) The '240J description on page 10, line 9, page 12, line 2, page 13, line 19, and page 15, line 19 of the specification is corrected to "80".

Attachment Claim 1, carbon dioxide permeability coefficient Pco2 at 27°C is 15 X 10-Io-10a STP) am/
(cIn2s, cmHg) and the ratio of carbon dioxide permeability coefficient Pco2 to oxygen permeability coefficient PO2 is 4.2 or more, and water vapor permeability coefficient PH2
0 is 80X10-9on3 (STP) am/ (oo2S,
■Hg) A packaging material for preserving the freshness of fruits and vegetables made of the following synthetic resin film.

2. Synthetic resin film contains ethylene and carbon number 3 to 12
The fruit and vegetable freshness-keeping packaging material according to claim 1, characterized in that it is composed of a copolymer of α-olefin.

3. Synthetic resin film contains ethylene and carbon number 3 to 12
or a blend of one or more copolymers of ethylene and α-olefins having 3 to 12 carbon atoms and low-density polyethylene. Claim 1 characterized in that
Packaging materials for preserving the freshness of fruits and vegetables, as described in .

4. Copolymers of ethylene and α-olefin having 3 to 12 carbon atoms include ethylene-butene-1 copolymer, ethylene-hexene-1 copolymer, ethylene-methylpentene-1 copolymer, and ethylene-octene-1 copolymer. Copolymer, selected from 1
The fruit and vegetable freshness-keeping packaging material according to any one of claims 1 to 3, characterized in that the packaging material is one or more types.

5. Claims 1 to 4 which are a copolymer of ethylene and an α-olefin having 3 to 12 carbon atoms or ultra-low density polyethylene.
The packaging material for preserving the freshness of fruits and vegetables as described in any one of the above.

6. Carbon dioxide permeability coefficient P of fruits and vegetables at 27°C
co2 is 15 x 10-”■3 (STP) mouth/(■2S,
■Hg) and the ratio of carbon dioxide permeability coefficient Pco2 to oxygen permeability coefficient PO2 is 4.2 or more, and water vapor permeability coefficient PH2
0 is 80 X 10-'■3 (STP)■/(■2S,
■ Hg) Packed with the following packaging material made of synthetic resin film, carbon dioxide gas is released from inside the package to the outside to suppress anaerobic respiration of fruits and vegetables, while controlling the amount of oxygen permeating inside the package. A method for preserving the freshness of fruits and vegetables by suppressing breathing.

7. Synthetic resin film contains ethylene and carbon number 3 to 12
7. The freshness-keeping packaging method for fruits and vegetables according to claim 6, characterized in that the method is made of a copolymer of α-olefin.

8. Synthetic resin film contains ethylene and carbon number 3 to 12
or a blend of one or more copolymers of ethylene and α-olefins having 3 to 12 carbon atoms and low-density polyethylene. 7. The freshness-keeping packaging method for fruits and vegetables according to claim 6.

9. Copolymers of ethylene and α-olefin having 3 to 12 carbon atoms include ethylene-butene-1 copolymer, ethylene-hexene-1 copolymer, ethylene-methylpentene-1 copolymer, ethylene-octene-1 copolymer 9. The freshness-keeping packaging method for fruits and vegetables according to any one of claims 6 to 8, characterized in that the packaging method uses one or more copolymers selected from the following.

10. The freshness-keeping packaging method for fruits and vegetables according to claim 6, wherein the packaging material is a copolymer of ethylene and an α-olefin having 3 to 12 carbon atoms or ultra-low density polyethylene.

11. Carbon dioxide permeability coefficient Pc of fruits and vegetables at 27°C
o2 or 15 X 10-” mouth 3 (STP>■/(■2S,
Hg) and above, the ratio of carbon dioxide permeability coefficient Pco2 to oxygen permeability coefficient Po2 is 4.2 or more, and water vapor permeability coefficient PH2
0 is DanOX 10-9aL13 (STP) CEI/ (
am2s, czHg) or less, and releases carbon dioxide to the outside to suppress anaerobic respiration, while controlling the amount of oxygen that permeates into the interior to suppress respiration. A package for preserving the freshness of fruits and vegetables.

12. Synthetic resin film contains ethylene and 3 to 1 carbon atoms
12. The fruit and vegetable freshness-keeping package according to claim 11, characterized in that it is composed of a copolymer of α-olefin of No. 2.

13. Synthetic resin film contains ethylene and 3 to 1 carbon atoms
Consisting of a blend of two or more copolymers of α-olefins selected from 2 or a blend of one or more copolymers of ethylene and α-olefins having 3 to 12 carbon atoms and low-density polyethylene. 12. The fruit and vegetable freshness-keeping package according to claim 11.

14. Copolymer of ethylene and α-olefin having 3 to 12 carbon atoms, ethylene-butene-1 copolymer, ethylene-
Hexene-1 copolymer, ethylene-methylpentene-1
Claim 11 characterized in that it is one or more selected from a copolymer and an ethylene-octene-1 copolymer.
The fruit and vegetable freshness-keeping package described in any one of items 1 to 13.

15. The fruit and vegetable freshness-keeping package according to any one of claims 11 to 14, wherein the copolymer of ethylene and α-olefin having 3 to 12 carbon atoms is ultra-low density polyethylene.

Claims (15)

[Claims] The carbon dioxide gas permeability coefficient Pco_2 at 1.27℃ is 15×10^-^1^0cm^3 (STP) cm/(c
m^2. s. cmHg) and above, the ratio of carbon dioxide permeability coefficient Pco_2 to oxygen permeability coefficient Po_2 is 4.2 or more, and water vapor permeability coefficient P
H_2O is 240X10^-^9cm^3 (STP) cm/(cm
^2. s. cmHg) A packaging material for preserving the freshness of fruits and vegetables, which is made of a synthetic resin film having the following properties. 2. 2. The freshness-keeping packaging material for fruits and vegetables according to claim 1, wherein the synthetic resin film is composed of a copolymer of ethylene and α-olefin having 3 to 12 carbon atoms. 3. The synthetic resin film is a blend of two or more selected from copolymers of ethylene and α-olefin having 3 to 12 carbon atoms, or one type selected from copolymers of ethylene and α-olefin having 3 to 12 carbon atoms. The fruit and vegetable freshness-keeping packaging material according to claim 1, characterized in that it is made of a blend of the above and low-density polyethylene. 4. Copolymers of ethylene and α-olefin having 3 to 12 carbon atoms include ethylene-butene-1 copolymer, ethylene-hexene-1 copolymer, ethylene-methylpentene-1 copolymer, and ethylene-octene-1 copolymer. Polymer, selected from 1
The fruit and vegetable freshness-keeping packaging material according to any one of claims 1 to 3, characterized in that the packaging material contains one or more kinds of fruits and vegetables. 5. The freshness-keeping packaging material for fruits and vegetables according to any one of claims 1 to 4, wherein the copolymer of ethylene and α-olefin having 3 to 12 carbon atoms is ultra-low density polyethylene. 6. The carbon dioxide permeability coefficient Pco of fruits and vegetables at 27°C
_2 is 15 x 10^-^1^0cm^3 (STP) cm/(c
m^2. s. cmHg) and above, the ratio of carbon dioxide permeability coefficient Pco_2 to oxygen permeability coefficient Po_2 is 4.2 or more, and water vapor permeability coefficient P
H_2O is 240 x 10^-^9cm^3 (STP) cm/(cm
^2. s. cmHg) The fruits and vegetables are packaged with a packaging material made of a synthetic resin film as follows: carbon dioxide gas is released from the inside of the package to the outside to suppress anaerobic respiration of fruits and vegetables, while the amount of oxygen that permeates into the package is controlled to prevent respiration. A packaging method for preserving the freshness of fruits and vegetables, which is characterized by suppressing 7. 7. The freshness-keeping packaging method for fruits and vegetables according to claim 6, wherein the synthetic resin film is composed of a copolymer of ethylene and α-olefin having 3 to 12 carbon atoms. 8. The synthetic resin film is a blend of two or more selected from copolymers of ethylene and α-olefin having 3 to 12 carbon atoms, or one type selected from copolymers of ethylene and α-olefin having 3 to 12 carbon atoms. Claim 6: The product is made of a blend of the above and low density polyethylene.
The freshness-preserving packaging method for fruits and vegetables described in . 9. Copolymers of ethylene and α-olefin having 3 to 12 carbon atoms include ethylene-butene-1 copolymer, ethylene-hexene-1 copolymer, ethylene-methylpentene-1 copolymer, and ethylene-octene-1 copolymer. Polymer, selected from 1
9. The method for preserving the freshness of fruits and vegetables according to any one of claims 6 to 8, characterized in that the packaging method comprises one or more kinds of fruits and vegetables. 10. Claim 6 or 9 wherein the copolymer of ethylene and α-olefin having 3 to 12 carbon atoms is ultra-low density polyethylene.
The freshness-preserving packaging method for fruits and vegetables described in . 11. Carbon dioxide permeability coefficient Pco of fruits and vegetables at 27℃
_2 is 15 x 10^1^0cm^3 (STP) cm/(cm^
2. s. cmHg) or more, and the ratio of carbon dioxide permeability coefficient Pco_2 to oxygen permeability coefficient Po_2 is 4.2 or more, and water vapor permeability coefficient PH_2O is 240×10^-^9cm^3 (STP) cm/(cm
^2. s. cmHg) or less, the product is packaged with a packaging material made of a synthetic resin film and releases carbon dioxide gas to the outside to suppress anaerobic respiration, while controlling the amount of oxygen that permeates into the interior to suppress respiration. , fruit and vegetable freshness preservation packaging. 12. Synthetic resin film contains ethylene and carbon number 3 to 12
12. The fruit and vegetable freshness-keeping package according to claim 11, characterized in that it is composed of a copolymer of α-olefin. 13. Synthetic resin film contains ethylene and carbon number 3 to 12
A blend of two or more selected from copolymers of α-olefins, or a blend of one or more copolymers of ethylene and α-olefins having 3 to 12 carbon atoms and low-density polyethylene. 12. The fruit and vegetable freshness-keeping package according to claim 11. 14. Copolymers of ethylene and α-olefin having 3 to 12 carbon atoms include ethylene-butene-1 copolymer, ethylene-hexene-1 copolymer, ethylene-methylpentene-1 copolymer, and ethylene-octene-1 copolymer. The fruit and vegetable freshness-keeping package according to any one of claims 11 to 13, characterized in that it is one or more selected from polymers. 15. The fruit and vegetable freshness-keeping package according to any one of claims 11 to 14, wherein the copolymer of ethylene and α-olefin having 3 to 12 carbon atoms is ultra-low density polyethylene.