JPH0799992B2 - Vegetable and fruit packaging paper and packaging container using this paper - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wrapping paper for maintaining the freshness of fruits and vegetables and a container made of this paper.

[0002]

2. Description of the Related Art Various attempts have heretofore been made to maintain the freshness of fruits and vegetables. For example, it is packed with a non-breathable packing material to prevent moisture from escaping, the storage temperature is lowered, an oxygen scavenger is used to support breathing, and ethylene gas is adsorbed to prevent ripening. Various methods have been proposed.
For example, Japanese Examined Patent Publication No. 38-2757 describes that a high-pressure polyethylene film is used to wrap vegetables and store them in a refrigerator to prevent water from evaporating and ripening to be preserved.
In Japanese Patent Laid-Open No. 61-216640, fruits and vegetables are packaged using a synthetic resin film having a carbon dioxide gas to oxygen permeability ratio (CO ₂ / O ₂ ) of 3 to 4 and stored under controlled respiration. It is stated. However, even if the film is used as described above, a sufficient freshness preservation effect of fruits and vegetables cannot be obtained.

[0003]

The problem with the prior art is that the basic problem of the loss of freshness of fruits and vegetables has not been fully elucidated, so the problem of preservation of freshness could not be solved to a satisfactory degree. .

According to the research conducted by the present inventors, fruits and vegetables exhibit a life reaction during storage, and when they breathe, plant hormones and enzymes also act. Therefore, for example, if ethylene gas is present in the storage atmosphere, aging hormone is actively secreted and aging is promoted. In addition, the composition of the storage atmosphere changes due to the respiration of fruits and vegetables, and when the oxygen content becomes too low and carbon dioxide gas increases, ateless breathing occurs and alcohol fermentation progresses, producing aldehydes and ammonia, and the freshness decreases. However, on the other hand, when there is a lot of oxygen, breathing is performed vigorously and maturation proceeds. As described above, the composition of the preservation atmosphere plays an important role in maintaining the freshness of fruits and vegetables, and not only the carbon dioxide gas but also the amount of oxygen must be controlled to an appropriate value.

Most fruits and vegetables are 80-95.
%, The water content is high, and when these are left under low humidity, water evaporates more violently than tissues such as pericarp and leaves, and this water loss immediately causes wilting and the freshness decreases.
Loss of 5% or more of water usually causes some change in appearance.

The present inventors paid attention to the physiology of such plants and studied to adjust the composition of gas in the preservation atmosphere. As a result, in order to maintain the freshness of fruits and vegetables, the evaporation of water is suppressed, the amount of oxygen present in the storage atmosphere is adjusted to be in the range of 1 to 16%, preferably 2 to 12%. It has been clarified that it is necessary to minimize the existing amount of carbon dioxide gas in the range of 0 to 20%, preferably 2 to 15%.

The inventor of the present invention uses a carbon dioxide gas permeability coefficient P at 27 ° C. as a packaging material for forming the above-mentioned storage atmosphere.
co ₂ is 15 × 10 ⁻¹⁰ cm ³ (STP) cm /
(Cm ² · S · cmHg) or more, the ratio of the carbon dioxide gas permeability coefficient Pco ₂ to the oxygen permeability coefficient Po ₂ is 4.2 or more, and the water vapor permeability coefficient PH ₂ O is 80 × 10 ⁻⁹ cm.
The invention of a freshness-maintaining packaging material for fruits and vegetables, which is made of a synthetic resin film having ³ (STP) cm / (cm ² · S · cmHg) or less, has been completed. This is the invention of Japanese Patent Application No. 2-103131.

The inventor of the present invention further conducts research to improve the paper to be the most widely used packaging material, that is, the paper, which has the ability to form the above-mentioned preservation atmosphere, so as to have a fresh preservation effect of fruits and vegetables. succeeded in.

Further, it has been clarified that a sealed container such as a bag, a box or a tray using this paper and a corrugated cardboard container using this paper as an outer liner also show excellent storability.

[0010]

[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 the equilibrium state and the equilibrium state is maintained. If this equilibrium does not cause atelectasis, there is little secretion of aging hormones, there is no acceleration of aging, and breathing is possible, the freshness of fruits and vegetables is maintained for a long time. In other words, by releasing as much carbon dioxide gas as possible generated by breathing in the preservation atmosphere to the outside, and introducing an appropriate amount of oxygen from the outside into the preservation atmosphere to balance the preservation atmosphere within the above range, the fruits and vegetables are made dormant. It keeps the freshness.

As a result of various researches for producing such a state, the present inventors have obtained a new finding that fruits and vegetables cannot be put into a dormant state unless the packaging material is improved, and have improved the wrapping paper. The present invention has been completed.

According to the present invention, (A) the paper must be coated with a resin layer, but in view of the wrapping property, ethylene and α having 3 to 12 carbon atoms have a low density of 0.917 g / cm ³ or less. The need to use a copolymer of olefins,

(B) The resin layer coated on the paper has a carbon dioxide gas permeability coefficient Pco ₂ of 8 × 10 ⁻¹⁰ cm.
³ (STP) cm / (cm ² · S · cmHg) or more, the storage atmosphere cannot be satisfied no matter how the other conditions are changed. Next, the carbon dioxide gas permeability coefficient Pco ₂ and the oxygen permeability coefficient Po
_It is necessary that the ratio of ₂ be 3.5 or more, and if it is 3.5 or less, the concentration of carbon dioxide and oxygen cannot be sufficiently controlled, and fruits and vegetables cannot be kept in a dormant state. The coefficient PH ₂ O is 80 × 10 ⁻⁹ c
If it is not less than m ³ (STP) cm / (cm ² · S · cmHg), the amount of moisture released to the outside of the packaging material will increase, and the moisture of the fruits and vegetables in the packaging will evaporate vigorously, causing withering and keeping the fruits and vegetables fresh. Things impossible. By clarifying the above, a wrapping paper invention having excellent preservation of freshness was completed.

Therefore, the present invention provides a synergistic effect of fresh preservation of fruits and vegetables by combining all of the above conditions with each other.

The present invention provides "1. A copolymer of ethylene and an α-olefin having 3 to 12 carbon atoms having a density of 0.917 g / cm ³ or less,
Carbon dioxide permeability coefficient at 27 ° C. is 8 × 10 ⁻¹⁰ cm
³ (STP) cm / (cm ² · S · cmHg) or more,
Water vapor permeability coefficient is a permeability coefficient ratio _Pco 2 / Po ₂ is 3.5 or higher ^{80 × 10 -9 cm 3 (STP} ) cm / (c
A fruit and vegetable wrapping paper having a resin layer of m ² · S · cmHg) or less coated on at least one side. 2. The fruit and vegetable packaging paper according to claim 1, wherein the copolymer of ethylene and an α-olefin having 3 to 12 carbon atoms is an ultra-low density LLDPE having a density of 0.912 or less. 3. A fold-proof wrapping paper for fruits and vegetables comprising the resin-coated wrapping paper according to claim 1 or 2. 4. A vegetable and fruit packaging paper container using the packaging paper according to claim 1 or 2 on a container wall. 5. A cardboard box for storing fruits and vegetables, which uses the wrapping paper according to claim 1 or 2 as at least an outer liner material. Regarding

In the present invention, the coating resin layer is as described above,
It contains an ethylene-α-olefin copolymer having a density of 0.917 g / cm ³ or less, and has a carbon dioxide gas permeability coefficient Pco.
₂ is 8 × 10 ⁻¹⁰ cm ³ (STP) cm / (cm ²
It is necessary that the ratio of the carbon dioxide gas permeability coefficient Pco ₂ to the oxygen permeability coefficient Po ₂ is 3.5 or more at S.cmHg) or more.

The water vapor permeability coefficient PH ₂ O is 80 × 1.
^{0 -9 cm 3 (STP) cm} / (cm 2 · S · cmH
g) Must be less than or equal to

Next, the resin layer used in the present invention will be described. The resin layer satisfying the requirements of the transmission characteristics of the present invention can be formed of a single synthetic resin, but it is necessary to independently satisfy the requirements of different characteristics described above, so that it is composed of a plurality of synthetic resins. desirable. Typical examples of such synthetic resins include ethylene and α-olefin copolymers having 3 to 12 carbon atoms, such as ethylene-butene-1 copolymer, ethylene-hexene-1 copolymer and ethylene-4-.
Methylpentene-1 copolymer and ethylene-octene-
One copolymer or the like can be used, and it is preferable to use it as a blend of at least two kinds selected from these resins. Also, these ethylene and C3 to C12
It is also possible to use a blend of the α-olefin copolymer and low density polyethylene. To obtain a particularly high carbon dioxide permeability coefficient, a low-density ethylene-α-olefin copolymer having a relatively high α-olefin copolymerization ratio, or
It is preferable to use a so-called ultra-low density ethylene-α-olefin copolymer having a high copolymerization ratio of α-olefin as a main component. At least two types of resins to be constituted, for example, a combination of low density polyethylene and ethylene-hexene-1 copolymer, ethylene-butene-1 copolymer and ethylene-hexene-1 copolymer, etc. are selected and used. Is preferred.

Further, as another method for obtaining a resin layer satisfying the requirement of the transmission characteristics of the present invention, the above-mentioned resin alone or a blend of a plurality of resins is used as a base polymer, while ethylene-vinyl acetate copolymer is used. United (EVA),
Ethylene-acrylic acid copolymers, ethylene copolymers such as ethylene-methyl methacrylate copolymers, ethylene or α-olefin-propylene-non-conjugated diene terpolymers, or styrene / butadiene block copolymers, styrene / isoprene blocks A resin such as a hydrogenated product of a copolymer may be blended and used. When these resins are used as a single resin as shown in Examples below, it is difficult to meet all the requirements of the permeability of the present invention, the laminating strength with paper is decreased, and the bending process after laminating is performed. As a result, cracks and breakages tend to occur.
It is necessary to use a blending ratio of 0:10 to 50:50.

Although the detailed reason why the selective permeation ratio of carbon dioxide gas and oxygen is increased by blending the resins having different repeating units is not clear, the present inventor has found that molecular chains having different molecular motility are used. This is because there are regions that exist at different concentrations and the permeability of both gases in that region changes depending on the molecular chain concentration.

In these resin layers, phenolic, organic sulfur, organic nitrogen, organic phosphorus, and other antioxidants or heat stabilizers, metallic soaps, and other fatty acids are used according to a method known per se. Lubricants such as esters and fatty acid derivatives, antifogging agents, antistatic agents, calcium carbonate, white carbon, titanium white, magnesium carbonate, magnesium silicate, carbon black, various clays, inorganic fillers such as natural or synthetic zeolites, or Other colorants and other compounding agents can be compounded in a compounding ratio known per se.

The thickness of the coating resin layer depends on the type of resin used and its physical strength, and the relationship of the properties of the paper used,
Depending on the case, it is necessary to properly set it in consideration of the types of fruits and vegetables to be packaged, the storage temperature, etc.
-60 μm, preferably 10-40 μm.

The melt index (MI) of the resin used in the present invention is not particularly limited.
It is preferable to use one having a value of about 0.1 to 10 g / 10 minutes (according to JIS K6760).

The resin layer of the present invention can be formed by extrusion or laminating a resin film, a sheet or the like. Further, for the purpose of improving the adhesiveness to paper and the surface characteristics of the resin coating layer, lamination using a multi-layer die or a multi-layer film formed in advance by a multi-layer die can be used. In this case, these multi-layer resin layers Needless to say, it satisfies the transparency specified in the claims.

It is of course preferable to print on the surface of these resin layers, from the viewpoint of ensuring the aesthetic appearance of the packaging container, and it is also possible to print before forming the resin layer on the paper. Since the thickness of the printing layer is thin and it is not a continuous film, the influence on the permeability is extremely slight. Particularly in the former case, it is effective to perform treatment such as corona discharge treatment by a generally known method after resin coating or before coating in the case of film, from the viewpoint of increasing ink adhesion and preventing scratch resistance. Is.

The paper of the present invention is a paper made from cellulose pulp, such as kraft paper, art paper, general printing paper or roll paper, thin paper, or liner, corrugated cardboard base paper such as core, Manila ball, white ball, etc. So-called paperboard such as white paperboard can be used, and paper in which synthetic resin fibers such as polyethylene are mixed with pulp can also be used. The wrapping paper of the present invention may be wrapped by sealing fruits and vegetables like a normal wrapping paper by sealing and sealing the joint part of the wrapping paper, and storing the fruits and vegetables as a bag or a box-shaped container and opening the opening. It may be sealed or covered with a lid. When sealed in this way, the atmosphere inside becomes proper and the freshness of fruits and vegetables is maintained.

When the wrapping paper of the present invention is used, it is possible to use a publicly known means effective for preservation of freshness of fruits and vegetables. For example, when a gas adsorbent against ethylene, aldehyde, etc. generated from fruits and vegetables, a moisturizer or a hygroscopic agent to control the moisture content of the bag, or an oxygen scavenger or a carbon dioxide gas remover is more effective in maintaining freshness. There is. These auxiliaries are usually used in the form of another bag inside the packaging paper of the present invention, but may be coated on the packaging paper of the present invention or impregnated with pulp or the like during papermaking. Alternatively, a method of mixing papers, or mixing with a resin is also effective.

[0028]

[Operation] The movement of gas generated between the atmosphere in the package and the outside air during storage of fruits and vegetables will be briefly described. Carbon dioxide gas CO ₂ generated by respiration of fruits and vegetables permeates the packaging paper and is diffused to the outside air. On the other hand, oxygen O ₂ consumed by respiration of fruits and vegetables penetrates the wrapping paper from the outside air and penetrates into the package. Here, in order to form an atmosphere that keeps fruits and vegetables in a dormant state, the carbon dioxide gas in the package is diffused to the outside air as much as possible to reduce the existing amount, and the invading oxygen is controlled to control the existing amount. It is important to control the amount so that the minimum necessary breathing is performed.

As another effect of using the wrapping paper of the present invention, the wrapping paper of the present invention has a high gas permeability and releases ethylene gas generated by fruits and vegetables very efficiently to the outside. It has the effect of suppressing the increase of ethylene gas concentration inside and preventing the aging of fruits and vegetables. The detailed operation and effects will be shown together with a comparative test in the section of Examples. By adjusting the atmosphere of the present invention, an extension of the fresh preservation days of 150% or more was recognized as compared with the conventional package.

The packaging paper of the present invention has a carbon dioxide gas permeability coefficient P.
and co _2, carbon dioxide gas permeability coefficient Pco ₂ and the oxygen permeability coefficient P
The ratio of o ₂ and the water vapor transmission coefficient PH ₂ O must all be within a certain range of numerical values. This is explained in detail in the Examples section below.

Further, the wrapping paper of the present invention is excellent in the bending workability, and even if the folding work is performed, the gas permeability and the water vapor permeability are not adversely affected. This performance is very effective for forming containers such as boxes.

Next, the present invention will be specifically described with reference to Examples.

[0033]

EXAMPLES First, the evaluation of the gas and water vapor permeation characteristics at 27 ° C. of various films used in the following examples will be described.

(1) For gas permeability measurement, a mixed gas permeability measuring device (LYSSY GPM-20) using a commercially available gas chromatography as a detector.
0) was used. Carbon dioxide gas and air were flowed to the inflow side of the film at normal pressure at a volume ratio of 1: 4, and helium gas was used as the carrier gas on the exhaust side, and the gas composition on the exhaust side was measured moment by moment. Correct the gas count number with a calibration curve created in advance, determine the permeation amount at each time, obtain the gradient by the least squares method from those points, and consider the thickness of the film used and the effective area of the permeation cell. Permeability coefficient Pco ₂ , Po ₂ (cm ³ (STP) cm
⁻² cm ⁻¹ s ⁻¹ cmHg ⁻¹ ) was calculated. Also,
The transmission coefficient ratio Pco ₂ / Po ₂ was obtained from these two values. Both measurements were performed at 27 ° C in the transmission cell and chamber.
Was kept constant.

(2) Water vapor permeability A commercially available water vapor permeability tester (LYSSY L
80-4000 type) and 25 as a standard sample
A biaxially stretched polyethylene terephthalate film having a thickness of μm was used by measuring the moisture permeability in advance by the cup method. According to this method, the water vapor permeability is g / (m ² · da
It is calculated in units of y). Therefore, here, from this measured value, the film thickness and the water vapor pressure at 27 ° C. (2.67
cm Hg), cm ³ (STP) cm / (cm ²
・ S · cmHg) was converted to the unit of water vapor permeability of the coated paper. For example, the thickness is 20 μm and the transmittance is 5
In the case of 0 g / (m ² · day) coated paper, it is 5 when converted
4 × 10 ⁻⁹ cm ³ (STP) cm / (cm ² · S · c
It becomes a transmission coefficient of mHg).

The permeability of the actual package can be estimated by using the permeability data of the resin-coated paper obtained by measuring by the above method. For example, the corrugated board of Example 1 described later (length L = 288, width W = 190, height H = 1
15 mm outer size), the effective surface area excluding the part used for sealing the end or corner is 1650 cm ²
And the pressure difference between carbon dioxide and oxygen inside and outside the package is 0.
When 2 atm, when using the resin-coated paper of the present invention 1 examples, Pco ₂ 86 as the transmission characteristics of the package
cc (STP) hr, Pco ₂ / Po ₂ 3.7, PH ₂
Calculated as O 2.5 g / day. On the other hand, this package was sealed in an empty state, and then the transmission characteristics were measured at 27 ° C. In the case of carbon dioxide gas, the inside of the package is filled with nitrogen 80:
After replacing with a mixed gas of carbon dioxide gas 20 (volume ratio), the permeability at a pressure difference of 0.2 atm was determined from the curve obtained by measuring the time change of this gas composition by gas chromatography. Further, in the case of oxygen, after completely replacing the inside with nitrogen, a time change curve of oxygen concentration was measured by the same method to determine the permeability at a pressure difference of 0.2 atm. For water vapor, the relative temperature (RH) is 97% at 27 ° C.
The package with a saturated salt solution that can be maintained at 27 ℃ RH
The sample was allowed to stand in a 25% chamber, its time change in weight was measured, and the difference in water vapor concentration was converted to obtain the transmittance. It is confirmed that the actual measurement value thus obtained and the previously calculated value are in good agreement with the difference of 10% at the maximum, and the permeation characteristic of the package can be estimated more accurately than the permeation characteristic of the resin-coated paper used. It was

(3) Permeability after low temperature bending process The folding processability of resin coated paper is JIS Z1514.
Polyethylene processed paper, 6.5 According to the evaluation method of cold resistance,
The test was carried out on a 100 × 100 mm test piece with the resin-coated surface facing outside. After bending in two directions at right angles, gas permeability and water vapor permeability were measured by the methods described above. In any of the above measurements, the arithmetic mean value of three measurements was taken as the measured value. [Example 1]

Present Invention 1 On the surface of a liner base paper for corrugated board having a basis weight of 280 g / m ² ,
Low density polyethylene LDPE (density ρ = 0.918) polymerized by the high pressure method and so-called ultra-low density LLDPE (ρ = 0.90) copolymerized from ethylene and butene-1.
The resin mixture having a weight ratio of 60:40 of 5) was applied to a resin film thickness of 15 μm.
Extrusion lamination was performed at 13.7 g / m ^{2 in} terms of m and weight per unit area. As conditions, the resin temperature directly below the die is 320 to 325 ° C., and the laminating speed is 100 m /
min, liner surface corona treated 5 kW was used. Comparative Example 1 LDPE (density ρ = 0.918) for comparison Comparative Example 2 Poly 4-methylpentene 1: TPX Comparative Example 3 Polyethylene terephthalate: PET was extruded according to the above conditions so that the resin film thickness was 15 μm. Lamination was done. Gas and water vapor permeation characteristics of these resin-coated liner materials were evaluated by the above-described method, while using the water-based bond by a corrugator with these resin-coated liners as the outer surface, the basis weight was 180 g / m ² The core and the inner surface of the core were coated with LDPE (density ρ = 0.918) at a film thickness of 20 μm, and a liner having a basis weight of 280 g / m ² was attached to each to obtain corrugated paperboard. For these paperboards,
Ordinary die-cutting was performed and the joints were joined using a hot melt adhesive, and A-1 specified in JIS Z1507 was used.
Shaped cardboard, (length L = 288, width W = 190, height H
= 115 mm) was created.

For 5 kinds of the above-mentioned corrugated board to which conventional corrugated board without resin coating was added for comparison, 2 kg each of blue plum (variety: Minamitakaume) pre-cooled for 8 hours in a pre-cooling box at 10 ° C. after harvest Then, using an adhesive tape made of biaxially oriented polypropylene with a width of 40 mm as a base material, the lap ends including the upper and lower flap abutting parts and the corner parts are sealed in an H shape, and the end part of the splice margin is further sealed. Was completely sealed. Ten cases were prepared for each type and stored in an atmosphere of 20 ° C. and 65% RH. After harvest 3
5 cases a day, 5 days a day, and the remaining 5 cases were opened, and the yellowing, browning or softening of blue plum and the weight loss rate were evaluated. , Was the percentage (%) of changes in pericarp in all individuals, and the percentage was (%) based on the total initial weight. The results are shown in Table 1.

[0040]

[Table 1]

^* Pco ₂ × 10 ¹⁰ cm ³ (STP)
cm / (cm ² · S · cmHg), PH ₂ O × 10 ⁹ c
m ³ (STP) cm / (cm ² · S · cmHg)

According to the results shown in Table 1, when the poly-4-methylpentene 1 having a large carbon dioxide gas permeability coefficient of Comparative Example 2 was used for coating, the oxygen permeability was considerably high because of the small permeability coefficient ratio. Further, since the film is cracked and cracked by the low temperature bending process, Pco ₂ is large, and Pco ₂ is large.
/ Po ₂ tended to become smaller. Reflecting this permeation property, in the storage test on corrugated cardboard, there was almost no suppression of respiration, so it was observed that yellowing occurred 3 days after harvesting.
In the 6th day, as much as 70% of yellowing occurred in the 6th plot. This tendency was effective in preventing the weight loss due to transpiration as compared with the case of Comparative Example 4 not coated with resin, but the yellowing was prevented. There was almost no effect. In the polyethylene terephthalate coating, carbon dioxide permeability is remarkably low, while PH ₂₀ is remarkably large, as is apparent from Comparative Example 3, and craze-like minute cracks were generated in the low temperature bending process, and the permeability was slightly changed, but the film cracked. Was not enough to cause. In this case, the carbon dioxide concentration in the corrugated cardboard became extremely high, atelectasis occurred, browning of the peel frequently occurred 3 days after harvesting, and most of them became gas-injured fruits 6 days later. In addition, a significant weight reduction was shown, reflecting the fact that the water vapor transmission rate is extremely large. In the low density polyethylene (LDPE) coating by the high pressure method, which is usually found in Comparative Example 1, the more effective Pco ₂ , P
It was difficult to achieve the co ₂ / Po ₂ ratio, and a slight change in the permeability due to the slight craze in the low-temperature bending process was also observed. A slight browning fruit occurred 3 days after harvesting, and further 6 days later, It showed a tendency to increase. Here, when the fruit evaluated when the cardboard was opened was left at room temperature for about 3 days,
Many of the fruits that appeared to be healthy turned brown, and it was revealed that the effects of respiratory disorders were still significant.

On the other hand, LDPE of the present invention 1 and ultra-low density LL
The coating made of the DPE blend had a high carbon dioxide permeability and a suitable oxygen supply due to the high Pco ₂ / Po ₂ ratio, so that even after 6 days of harvesting, yellowing was considerably suppressed and browning occurred. There was no occurrence, the weight loss was extremely small, a well-balanced storability was secured, and no sign of respiratory disorder was observed even when left after opening. Further, this coating resin was also excellent in bending workability, and almost no change in permeability was observed after working. Example 2 The present invention 2 uses an 80:20 blend of LDPE (ρ = 0.918) and ultra-low density LLDPE on the surface of the liner base paper for corrugated board having a basis weight of 220 g / m ² , and the present invention 3 The ratio of the above blend is 60:40,
The present invention 4 uses a blend having a blend ratio of 40:60, and the present invention 5 uses a super low density LLDPE (C4, ρ
= 0.903) was used to perform extrusion lamination according to the method of Example 1 with a film thickness of 25 mm. Gas and water vapor permeation characteristics of these resin-coated liner materials were evaluated. On the other hand, these were used as an outer liner, and LDPE was used for the inner core and the inner core of a basis weight of 180 g / m ^2.
(Density ρ = 0.918) was coated with an inner liner having a basis weight of 220 g / m ² coated with a film thickness of 25 μm by an aqueous bond (Konishi # 645) to obtain a corrugated paperboard. Further, die-cutting and box-making are performed by the method described above, and A-1 type corrugated board (length L = 288, width W = 190, height H = 115
mm) was created. On the other hand, as a comparative example, Comparative Example 6 is an LD
PE (ρ = 0.918) and LLDPE (C8, ρ = 0.
Comparative Example 7 uses LDPE (ρ = 0.918) and ultra low density LLDPE, using a 60:40 blend with 927).
A 90:10 blend with (C4, ρ = 0.903) was used. Further, for 7 types including the conventional corrugated board comparative example 5 without resin coating for comparison, after leasing and precooling the Cabos (variety, Oita No. 1) harvested in mid-September,
Using an adhesive tape containing 2 kg of each and having a width of 40 mm as a base material of biaxially oriented polypropylene, seal the lap ends including the upper and lower flap abutting parts and the corner parts into an H-shape, and further splice The ends were sealed and completely sealed, and stored at 5 ° C. and 60% RH. After storage for about 2 months, the quality of the opened cabos was determined as follows: Yellowing, B.I. Pitting, C.I. Browning, D.I. The rate of occurrence of mold and other defects (%), and the rate of weight change (%) based on the initial weight per box were evaluated (storage section I). Then, for good storage, assuming the distribution using this box, the container was sealed again by the above method, left at 20 ° C. and 65% RH for 2 weeks, and then reopened for quality evaluation. (Storage area II).

Table 2 shows a summary of the transmission characteristics of the respective resin-coated papers and the results of the storage test of kabos made of corrugated board using the papers.

[0045]

[Table 2]

^* Pco ₂ × 10 ¹⁰ cm ³ (STP)
cm / (cm ² · S · cmHg), PH ₂ O × 10 ⁹ c
m ³ (STP) cm / (cm ² · S · cmHg) ^** A. Yellowing, B.I. Pitting, C.I. Browning, D.I. Mold, other (%)

In the conventional corrugated cardboard without the resin coating of Comparative Example 5, almost all of the corrugated products were yellowed even at low temperature storage because the respiration could not be suppressed, and a considerable weight reduction was shown. Also,
As a coating resin of Comparative Example 6, LDPE is a conventional LLDP.
Even if E is blended or the comparatively small amount of ultra-low density LLDPE of Comparative Example 7 is blended, the permeability coefficient of carbon dioxide is remarkably low, and the processing causes microcracks in the coating layer, resulting in a small permeability coefficient ratio. , It was difficult to sufficiently suppress the respiration of fruits and vegetables in a sealed container. For this reason, when stored in kabos, pitting and browning often occur due to breathing problems. The fruit was remarkably increased, and the quality was remarkably deteriorated, such as the formation of mold due to the softening of the skin.

On the other hand, when a certain amount or more of ultra-low density LLDPE is blended and used as the composition of the coating resin layers of the present inventions 2 to 5, relatively large carbon dioxide gas permeation coefficient and permeation coefficient ratio are obtained, There is little change in those values due to processing. For this reason, even in the storage of Kabos, it is possible to maintain the respiration-suppressed state in the sealed corrugated cardboard container using these resin-coated papers, and practically satisfactory preservability is obtained in any storage section. . [Example 3] LDP as Invention 6 was applied to the surface of a mixed paper made of pulp having a basis weight of 400 g / m ² and PE synthetic pulp.
E (ρ = 0.918) and ultra low density LLDPE (C6, ρ
= 0.910) 40:60 blend, and LDPE (ρ = 0.918), ultra-low density LLDPE (C6, ρ = 0.910) and SB copolymer water added as Invention 7. Using a blend of 40:30:30 of the product, LDPE (ρ = 0.918) and ultra low density LL according to the present invention 8.
Extrusion lamination was performed according to the method of Example 1 using a blend of DPE (C6 ρ = 0.910) and ethylene vinyl acetate copolymer (VA 20%) at 40:30:30 at a film thickness of 20 μm. I did. Gas and water vapor permeation characteristics of these resin-coated papers were evaluated according to the above method, while a tray having a heat-sealing flange was formed by a press molding method (width 110 mm, length 160 m).
m, height 30 mm). Comparative Example 9LLDP
About 5 kinds of coated paper obtained by using E (C4, ρ = 0.920) at a film thickness of 20 μm in the same manner as in Example 1 and further adding tray comparative example 8 without resin coating for comparison. , 300 g of yellow peach (variety, Sato Nishiki) immediately after harvest
First, 40 μm thick ultra-low density LLDPE (ρ = 0.9
05): LLDPE (ρ = 0.920), the tray flange was heat-sealed using a film having an antifogging property of 70:30. 22 trays of each type n = 10
The product was stored in an atmosphere at a temperature of 65 ° C and a relative temperature of 65% for 10 days. evaluated.

When the ordinary tray not coated with the resin of Comparative Example 8 is used, breathing is actively carried out, and after 10 days of storage, wilting and accompanying shaft effects proceed, and a large number of shaft dropouts occur, resulting in a large weight. It showed a tendency of aging, and the commercial property was completely lost. In addition, when general LLDPE was used as the coating resin of Comparative Example 9, the press moldability was poor, and the coating resin layer tended to crack at the curved surface of the corner of the tray, and microcracks were generated by the bending process, resulting in transmission characteristics. In particular, changes such as a decrease in the selective permeation ratio were observed. Reflecting these characteristics, the carbon dioxide concentration in the package became significantly high in the storage test, and many browning of the pericarp due to respiratory disorder was remarkable. Alcoholic odor was generated, and mold was also observed due to softening of the pulp, and the commercial value was lost.

On the other hand, in the present inventions 6 to 8 in which the ultra-low density LLDPE is used as a component of the coating resin, the press moldability is excellent, the carbon dioxide gas permeability is high, and the high selective permeation ratio required for proper oxygen supply. As a result, it showed a good storability that allows appropriate respiratory depression of the contents. In particular, when a hydrogenated product of a styrene / butadiene block copolymer or an ethylene / vinyl acetate copolymer of the present invention 8 (vinyl acetate content 20 mol%) is used as a component of the coating resin of the present invention 7, a selection is made. Perhaps because of the increased transmission ratio, the effect of improving storage stability was confirmed. The test results are shown in Table 3.

[0051]

[Table 3]

^* Pco ₂ × 10 ¹⁰ cm ³ (STP)
cm / (cm ² · S · cmHg), PH ₂ O × 10 ⁹ c
m ³ (STP) cm / (cm ² · S · cmHg) ^** A. Yellowing, B.I. Pitting, C.I. Browning, D.I. Mold, etc. (%) [Example 4] LDP is applied to a thin paper imitation paper having a basis weight of 50 g / m ^2.
E (ρ = 0.919) and ultra low density LLDPE (C4, ρ
= 0.905) in a 50:50 blend was extruded and laminated according to the method of the previous example so as to obtain a coating film thickness of 15 μm. The permeability of this coated paper is Pc
o ₂ : 15.6 × 10 ⁻¹⁰ cm ³ (STP) cm /
(Cm ² · S · cmHg), Pco ₂ / Po ₂ : 3.
7, PH ₂ O: 13.2 × 10 ⁻⁹ cm ³ (STP) c
It was m / (cm ² · S · cmHg). Using this coated paper as a lid material, LLDPE (C4, 120 μm thick)
ρ = 0.918) A package capable of filling spherical fruits and vegetables having a diameter of 60 mm prepared by vacuum forming from a film is filled with pre-cooled and pre-borrowed cabos, and -50 cm.
Heat sealing was performed under degassing of Hg.

When 500 packages of these packages were stored at 5 ° C. for 3 months, the non-defective product ratio was 98.6%, which was very good although there was a defective product due to a scratch on the peel at a part of harvesting.
Next, pack 10g of this package into cardboard,
After transporting by a mixed cargo of 00km trucks and storing at room temperature for 2 weeks assuming distribution conditions, there is no defect such as pinholes in the packaging, especially lid material, and the green color of Kabos can be maintained and freshness is maintained. Very effective for [Example 5] Three dimensions are adhered with the coated paper of Example 4 to measure the dimensions,
Create a bag containing 3 pieces with a length of 280 mm and a width of 120 mm,
After filling with cabos and degassing, the mouth of the bag was wrapped with an adhesive tape and sealed. Permeability of the coated paper _Pco 2: 15.
6 × 10 ⁻¹⁰ cm ³ (STP) cm / (cm ² · S ·
_{cmHg), Pco 2 / Po 2} : 3.7, PH 2 O: 1
3.2 × 10 ⁻⁹ cm ³ (STP) cm / (cm ² · S
-CmHg).

When these 500 packages were stored at 5 ° C. for 3 months, the rate of non-defective products was 98.6%, which was extremely good although there were defective products due to scratches on the pericarp at the time of partial harvesting.
Next, pack this package in cardboard boxes at a rate of 10 kg, and
After transporting by 000km truck mixed loading flight and storing at room temperature for 2 weeks assuming distribution conditions, there is no defect such as pinholes in the packaging and the green color of the kabos can be maintained sufficiently to maintain freshness. The effect was recognized.

[0055]

EFFECTS OF THE INVENTION By using the wrapping paper of the present invention, fruits and vegetables are kept in a dormant state and the fresh state is maintained, and the storage period is greatly extended.

Claims (5)

[Claims] 1. A copolymer containing ethylene and an α-olefin having 3 to 12 carbon atoms and having a density of 0.917 g / cm ³ or less, and a carbon dioxide gas permeability coefficient at 27 ° C. of 8 × 10 ⁻¹⁰ c.
m ³ (STP) cm / (cm ² · S · cmHg) or more, the permeability coefficient ratio Pco ₂ / Po ₂ is 3.5 or more, and the water vapor permeability coefficient is 80 × 10 ⁻⁹ cm ³ (STP) cm /
A fruit and vegetable wrapping paper obtained by coating at least one surface with a resin layer of (cm ² · S · cmHg) or less. 2. An ultra-low density LL in which a copolymer of ethylene and an α-olefin having 3 to 12 carbon atoms has a density of 0.912 or less.
The fruit and vegetable wrapping paper according to claim 1, which is DPE. 3. A wrapping paper for fruits and vegetables for folding, which comprises the resin-coated paper according to claim 1 or 2. 4. A vegetable and fruit packaging paper container using the packaging paper according to claim 1 or 2 as a container wall. 5. A cardboard box for storing fruits and vegetables, which uses the wrapping paper according to claim 1 or 2 as at least an outer liner material.