JP2002165555A - Wrapping film for vegetable/fruit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wrapping film for vegetable/fruit, suitable for MA wrapping, having excellent gas permeability with no reduction due to the water content transpired from vegetable/fruit, slightly clinging to the vegetable/fruit under such a wide range of temperature from low level to relatively high level so that water leak resulting in water rot of vegetable/fruit is hard to be caused. SOLUTION: This wrapping film for vegetable/fruit comprises a thermoplastic resin composition containing an anti-fogging agent and a specific uneven configuration comprising substantially continuous convex parts and discontinuous concave parts partitioned by the convex parts is formed on the surface of the film with which the vegetable/fruit comes in contact.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a packaging film for suppressing a decrease in freshness of fruits and vegetables, in particular, has an appropriate gas permeability even after packaging of fruits and vegetables, has little adhesion to fruits and vegetables, and hardly causes water rot. The present invention relates to a film for packaging fruits and vegetables.

[0002]

2. Description of the Related Art Conventionally, as a method for suppressing a decrease in freshness of fruits and vegetables, a method of controlling a gas composition of a storage atmosphere of fruits and vegetables has been known.
A (Controlled Atmosphere) storage is commonly performed. In recent years, also in packaging, in order to maintain the freshness of fruits and vegetables, the gas permeability of the packaging film is balanced with the respiratory volume of the fruits and vegetables, and the gas concentration in the packaging film in which the fruits and vegetables are hermetically sealed (hereinafter referred to as “MA”). (Modified Atmo
sphere) state)) (MA) (Modified Atmo
sphere Packaging) is in the limelight.

[0003] The gas permeability of a packaging film varies depending on the material and thickness of the film, and a technique of providing pores in the film to bring the inside of the packaging film into the MA state is disclosed in Japanese Patent Application Laid-Open No. 61-259982. JP-A-02-085
181 and Japanese Patent Application Laid-Open No. 05-329947. In the case of these fruits and vegetables packaging films, the water vapor evaporating from the fruits and vegetables enters the pores, thereby closing the pores and lowering the gas permeability, and the possibility that various bacteria may enter the pores. There was a problem.

As a method for improving the gas permeability of a packaging film without providing pores, JP-A-7-21536 discloses a method.
No. 7 discloses a technology of a film for maintaining freshness of fruits and vegetables by an ethylene-based polymer using a single-site catalyst, but since the thickness of a packaging film is as thin as 15 to 25 μm,
In addition to insufficient strength, rigidity (lumbar) is also insufficient, and there is a problem that packaging is difficult when using an automatic packaging machine.

[0005] On the other hand, water vapor evaporating from the fruits and vegetables is condensed on the inner surface of the packaging film, and the dew condensation water drops on the fruits and vegetables, causing a phenomenon that the fruits and vegetables rot (water rot). A technique for preventing this is disclosed in Japanese Patent Application Laid-Open No. 63-102634. No. 6,086,045. Certainly, if the fruit and vegetable packaging film is provided with anti-fogging properties, when water vapor evaporating from the fruit and vegetable condenses on the inner surface of the packaging film, the water film becomes uniform and looks beautiful at first glance. A water film intervenes with the inner surface of the container, whereby the fruits and vegetables and the packaging film adhere to each other, and water rot proceeds from the adhered portion.

Further, in order to maintain the freshness of fruits and vegetables,
Fruits and vegetables are stored and distributed in a temperature range of about 10 ° C., and there are cases where they are displayed at an environmental temperature of about 5 ° C. even when they are lined up at stores. Under such a low-temperature environment, the anti-fogging property is difficult to develop, and the decrease in transparency due to the adhesion of water droplets due to poor anti-fogging property not only lowers the commercial value, but also water droplets condensed on the inner surface of the packaging film fall to fruits and vegetables. This is a cause of promoting the water rot.

[0007]

DISCLOSURE OF THE INVENTION The present invention relates to a fruit and vegetable in a wide temperature range from a low temperature to a relatively high temperature, while having excellent gas permeability, without a decrease in gas permeability due to moisture evaporated from the fruit and vegetable. It is an object of the present invention to provide a film for packaging fruits and vegetables suitable for MA packaging, which has little adhesion to water and hardly causes water wetting which causes water rot of the fruits and vegetables.

[0008]

Means for Solving the Problems As a result of intensive studies, the present inventors have found that a substantially continuous convex portion is formed on a surface of a film made of a thermoplastic resin composition containing an anti-fogging agent, in contact with fruits and vegetables. The present inventors have found that a fruit and vegetable packaging film having a specific uneven shape formed of discontinuous concave portions partitioned by the convex portions achieves the above object, and completed the present invention based on this finding.

The present invention is constituted by the following. 1. On at least one surface of a film made of a thermoplastic resin composition containing an antifogging agent, an uneven shape composed of substantially continuous convex portions and discontinuous concave portions partitioned by the convex portions is formed, and the uneven shape is formed. Satisfies the following condition. 1) A thickness d _a is 0.003~0.05mm recess, the ratio d _a / d _b of thickness d _a of the concave portion to the thickness d _b of the projecting portion
Is 0.05 ≦ d _a / d _b ≦ 0.8. 2) the ratio S _a / S _b of the surface area S _a of the concave portion to the total surface area S _b of the irregularities formed film plane, 0.1 ≦
S _a / S _b ≦ 5.

[0010] 2. 1. The film in which the unevenness is formed has a light transmittance of 80 to 99% and a haze of 1 to 10%. The film for packaging fruits and vegetables according to the above item.

3. The thermoplastic resin is a polypropylene resin or a polyethylene resin, and has an oxygen permeability of 1,500 to 30,000 nmol / m ² · s · 100.
kPa, carbon dioxide permeability 6,000 to 120,000
0 nmol / m ² · s · 100 kPa, water vapor permeability at 40 ° C. is 10 to 200 g / m ² · 24 h.
Item or 2. A film for packaging fruits and vegetables according to the above.

4. (1) The thermoplastic resin film having an uneven shape is a stretched film stretched at an area magnification of 4 to 60 times. ~ 3. Any one of the terms
The film for packaging fruits and vegetables according to the above item.

[0013]

Embodiments of the present invention will be described below. Examples of the thermoplastic resin used in the thermoplastic resin composition for producing the fruit and vegetable packaging film of the present invention include polyolefin resins, polystyrene resins, polyvinyl chloride resins, polyester resins such as polyethylene terephthalate and polyethylene naphthalate, and urethane resins. ,
An acrylic resin, a polyamide resin, a polycarbonate resin, a fluorine resin, and the like are given.

Among them, polyolefin resins represented by polyethylene resins and polypropylene resins are preferred from the viewpoint of processability and economic efficiency. Further, when used in an automatic packaging machine for fruits and vegetables, the film needs to have a certain degree of rigidity, so that a polypropylene resin is preferred.

Examples of the polyethylene resin include an ethylene homopolymer, a binary or more random or block copolymer of ethylene with a monomer other than ethylene as a main component, and a mixture of two or more thereof. Can be In the present invention, the main component refers to a component that is the most common. Examples of the monomer other than ethylene include, but are not particularly limited to, α-olefins having 3 to 12 carbon atoms such as propylene, 1-butene, 1-pentene, 1-hexene, and 1-octene, and vinyl esters such as vinyl acetate. And acrylates such as ethyl acrylate, methacrylates such as methyl methacrylate, and carbon monoxide. These may be used alone or in combination of two or more.

In the present invention, the polypropylene resin may be a homopolymer of propylene, a binary or more random or block copolymer of propylene with a monomer other than propylene as a main component, or two or more of these. And mixtures thereof. Examples of the monomer other than propylene include, but are not particularly limited to, ethylene, 1-butene,
-Carbon number 2 of pentene, 1-hexene, 1-octene, etc.
To 12 α-olefins. These may be used alone or in combination of two or more.

The antifogging agent used in the present invention includes a nonionic surfactant, a cationic surfactant, an anionic surfactant, an amphoteric surfactant and the like. Specific examples include partial carboxylic acid esters of polyhydric alcohols such as sorbitan fatty acid ester, glycerin fatty acid ester, polyglycerin fatty acid ester, and sucrose fatty acid ester, polyoxyethylene sorbitan fatty acid ester, and polyoxyethylene glycerin fatty acid ester. Examples include polyoxyethylene derivatives of partial carboxylic acid esters of alcohols, amines and fatty acid amides.

Among them, the anti-fogging agent is selected from compounds represented by the following formula (1) and their neutralized salts with organic acids.
When the seeds or two or more kinds are used, the obtained fruit and vegetable packaging film exhibits excellent anti-fogging property at low temperatures, and therefore has a particularly excellent anti-fogging property due to a synergistic effect with the effect of improving the anti-fogging property by forming the uneven shape. It shows good transparency.

[0019] (Wherein R ₁ is an alkyl group, alkenyl group or acyl group having 8 to 22 carbon atoms, R ₂ and R ₃ are independently a hydrogen atom or an acyl group, a and b are independently a +
b is an integer of 1 or more to be 2 to 20, c is 0 or 1 to 1
An integer of 0, n represents 2 or 3. )

The compound represented by the above formula (1) includes
Amine compounds such as polyoxyethylene (8 mol) stearylamine, polyoxyethylene (2 mol) laurylamine, and polyoxyethylene (2 mol) tallowamine; amide compounds such as polyoxyethylene lauramide and polyoxyethylene stearylamide; And fatty acid esters of these amine compounds and amide compounds with fatty acids such as lauric acid, stearic acid, behenic acid and oleic acid. In addition, examples of the organic acid include carboxylic acid, sulfonic acid, phenol carboxylic acid and the like, and among them, carboxylic acid is preferable in view of reactivity and stability with the compound. Specific examples include lauric acid, stearic acid, behenic acid, oleic acid, and benzoic acid.

The antifogging agent is used singly or in combination of two or more, and exhibits antifogging properties on at least the surface of the film for packaging fruits and vegetables in contact with the fruits and vegetables. It is desirable that the content of the anti-fogging agent in the thermoplastic resin composition used for producing a film for packaging fruits and vegetables is 0.1 to 5% by weight, preferably 0.5 to 3% by weight. If the content is less than 0.1% by weight, the desired antifogging effect cannot be obtained, and if it exceeds 5% by weight, a large amount of the antifogging agent precipitates on the film surface, and However, there is a problem that it is difficult to open the container due to close contact, and it is difficult to package fruits and vegetables.

The thermoplastic resin composition contains commonly used antioxidants, hindered amine weathering agents, ultraviolet absorbers, surfactants such as antifogging agents and antistatic agents, antiblocking agents, slip agents, antibacterial agents and the like. Agents, fungicides, pigments, and the like can be added as necessary. However, in some cases, the film for packaging fruits and vegetables requires transparency so that the freshness of the contents can be confirmed. Therefore, according to ASTM-D1003. The measured light transmittance and haze (haze) are desirably 80 to 99% and 1 to 10%, respectively, and inorganic fillers such as calcium carbonate and talc having a refractive index significantly different from that of the thermoplastic resin. Is not preferred to be added in a large amount.

Further, an ethylene-diene elastic copolymer polymerized with a single-site catalyst or a known multi-site catalyst in order to improve gas permeability or flexibility,
An elastic copolymer such as an ethylene-propylene elastic copolymer or a styrene-butadiene-based elastic copolymer may be added.

In the fruit and vegetable packaging film of the present invention, the surface of the thermoplastic resin film in contact with the fruit and vegetable has a concavo-convex shape consisting of substantially continuous convex portions and discontinuous concave portions partitioned by the convex portions. The concave portion is formed in a shape of a square, a parallelogram, a rhombus, a circle, an ellipse, or the like surrounded by the convex portion. In the present invention, for the formation of a seal layer, bag making, and the like, when a discontinuous portion is partially provided in the convex portion within a range that does not impair the film strength or rigidity, the convex portion is substantially continuous. Consider

The uneven shape is determined depending on the type and quantity of the fruits and vegetables to be packaged, the storage environment temperature, and further considering the stretching ratio and the total average thickness when the thermoplastic resin film or sheet is stretched. From the standpoint of improving the film strength and rigidity, and at the time of stretching, the network pattern is preferred from the viewpoint of workability.

The following effects can be obtained by forming the irregularities. The contact area between the fruits and vegetables at the time of packaging is reduced, and the moisture evaporated from the fruits and vegetables and condensed on the inner surface of the packaging film is less likely to intervene between the fruits and vegetables packaging film and the fruits and vegetables, and water rot hardly occurs.

It is possible to easily control the gas permeability and the moisture permeability while maintaining the strength and rigidity of the film for packaging fruits and vegetables, and also to measure the gas permeation due to the evaporation of moisture from the fruits and vegetables after packaging the fruits and vegetables. Since there is no decrease in the degree, the film design for optimizing the gas concentration inside the packaging film becomes easy.

The unevenness of the surface of the fruit and vegetable packaging film makes it difficult for water droplets to be generated, thereby suppressing water rot. In addition, the transparency is maintained even in a low-temperature region where antifogging properties are difficult to develop, so that the commercial value of the fruit and vegetable is improved. I do.

Since the gas permeability is not controlled by forming pores such as a hot needle or a laser, invasion of various bacteria after packaging can be prevented.

The gas permeability and moisture permeability of the fruit and vegetable packaging film of the present invention are determined by the type and weight of the fruit and vegetable to be packaged, the environmental temperature conditions for storing and distributing the fruit and vegetable, the thickness and the vertical and horizontal dimensions of the packaging bag, and the packaging bag. The oxygen permeability is determined by the empty volume and the like, and is not particularly limited.
500-30,000 nmol / m ² · s · 100 kP
a, preferably 2,500 to 10,000 nmol / m
A range of ² · s · 100 kPa is desirable for forming the MA environment.

A commonly used film for packaging fruits and vegetables using the above-mentioned polypropylene-based resin or polyethylene-based resin and having no unevenness has an oxygen permeability of 1,000 to 3,000 nmol / m ² · s ·.
Although it is about 100 kPa, even if the film for packaging fruits and vegetables of the present invention is a film using the polypropylene-based resin or the polyethylene-based resin due to the formation of the above-mentioned uneven shape, the oxygen permeability is 1,500 to 30. , 0
100 nmol / m ² · s · 100 kPa, carbon dioxide permeability is 6,000 to 120,000 nmol / m ² · s
-The moisture permeability at 100 kPa and 40 ° C is 10 to 200.
g / m ² · 24 h can be controlled over a wide range, and it can have a sufficient function as a fruit and vegetable packaging film.

In the present invention, as a method of forming the uneven shape, a thermoplastic resin film is produced by a known processing technique such as a calendering device, a T-die device or an inflation device, and then the thermoplastic resin film is heated by a pair of heating devices. A method of sandwiching and cooling between embossing roll units, a method of melting and softening the thermoplastic resin film and pressing and cooling between a pair of cooling embossing roll units, and a method of extruding a thermoplastic resin into a molten state with an extruder or a calender roll. A method in which the material is pressed between a pair of cooling embossing roll units to cool the material is exemplified.

In the case where the irregular shape is provided only on one surface of the thermoplastic resin film, one having a concave and convex shape opposite to the film surface is formed on one roll surface, and the other roll is formed of a metal roll or rubber roll having a smooth surface. When forming irregularities on both surfaces of the thermoplastic resin film by using the above, two embossing rolls having irregularities are used.

When the film for packaging fruits and vegetables requires further rigidity and tensile strength, a uniaxial stretching or biaxial stretching technique is used. In this case, it is desirable to previously form irregularities on the thermoplastic resin film or sheet before stretching, and to form the irregularities on the stretched film, it is necessary to re-melt the film, In some cases, the effect of stretching is lost and the desired rigidity and tensile strength cannot be obtained.

In the biaxial stretching method, the thermoplastic resin film or sheet having the uneven shape is usually
The film is stretched at a stretching ratio of 2 to 8 times (area ratio of 4 to 60 times) in each of the biaxial directions of the machine direction and the transverse direction,
A simultaneous biaxial stretching method in which stretching is performed in the biaxial direction at the same time, a stretching method in which the film is stretched in the longitudinal direction and then in the horizontal direction, or a sequential stretching method in which the film is stretched in the horizontal direction and then stretched in the vertical direction may be used. If the area magnification is less than 4 times, uniform stretching cannot be performed.
If it exceeds 0 times, it tends to break during stretching. Also,
The stretched film thus obtained may be subjected to a relaxation treatment in a heating environment at a melting temperature or lower for the purpose of removing internal residual strain.

The thickness of the concave and convex portions formed on the film for packaging fruits and vegetables of the present invention varies depending on the required gas permeability, the area ratio of the concave and convex portions, and the like. the thickness d _a is, 0.003～0.05Mm preferably 0.004～0.03Mm, more preferably from 0.004～0.01Mm. The thickness of the recess is 0.0
When the thickness is less than 03 mm, stretching breaks or holes are easily formed in the concave portions, and when the thickness is more than 0.05 mm, the desired gas permeability as a fruit and vegetable packaging film becomes difficult to obtain.

[0037] The ratio d _a between the thickness d _b of the thickness d _a and the convex portion of the concave portion
/ D _{b is, 0.05 ≦ d a / d b} ≦ 0.8, preferably _{0.05 ≦ d a / d b ≦} 0.6, more preferably 0.1 ≦
d _a / d _b ≦ 0.4. The thickness ratio d _a / d _b is 0.8
When it is more than 0.05, it is difficult to obtain a gas permeability suitable for fruit and vegetable packaging, and when it is less than 0.05, the strength of the concave portion may be insufficient, or a hole may be formed during film formation or stretching. .

[0038] The thickness d _b of the convex portion is a range of values obtained from the thickness d _a and the thickness ratio d _a / d _b of the concave portion, is preferably 0.02~0.2mm When the thickness of the convex portion is less than 0.02 mm, breakage or the like is liable to occur at the time of forming an unstretched film or at the time of stretching a stretched film. The rigidity may be too high.

The ratio S _a / S _b of the concave area S _a and the convex area S _{b on} the surface of the film for packaging fruit and vegetables of the present invention on which the uneven shape is formed is 0.1 ≦ S _a / S _b ≦ 5. , Preferably 0.3 ≦ S _a / S _b ≦ 4, more preferably 0.5 ≦ S
S _a / S _b ≦ 3. When the ratio S _a / S _b is less than 0.1, the effect of improving gas permeability of the present invention cannot be obtained,
In addition, since the width of the convex portion is increased, the contact area with the fruits and vegetables is also increased, and it is difficult to obtain the effect of preventing the fruits and vegetables from being putrefactive.
When S _a / S _b exceeds 5, the width of the convex portion becomes narrow, which is preferable for the effect of improving the gas permeability and the effect of preventing rot of fruits and vegetables. However, the formation of the uneven shape on the embossing roll is preferable. It becomes difficult.

In the uneven shape of the thermoplastic resin film, the pitch of the concave portions or the convex portions (see FIG. 1) is 1 to 50.
mm, preferably 5 to 25 mm. When the pitch is more than 50 mm, the recesses easily come into contact with the fruits and vegetables, and the effect of reducing the contact area between the fruits and vegetables and the packaging film of the present invention is hardly obtained. When the thickness is less than 1 mm, the visibility of the fruits and vegetables in the packaging film is difficult to confirm because the transparency of the packaging film is poor.

When the film for packaging fruits and vegetables of the present invention is used for packaging fruits and vegetables, the film is formed such that the surface of the film on which the uneven shape is formed is the inner surface of the packaging bag, and the film on which the uneven shape is formed is formed. The fruits and vegetables are packaged so that they come into contact with each other, but depending on the shape and properties of the fruits and vegetables, the surface having the uneven shape may be packaged as the outer surface of the packaging bag unless the object of the present invention is impaired. Further, the packaging film is made into a packaging bag by a method such as heat sealing, ultrasonic sealing, high frequency sealing, etc. In order to facilitate heat sealing and the like, the surface of the fruit and vegetable packaging film is subjected to a co-extrusion method, a wet lamination method. The seal layer may be formed by a known method such as a dry lamination method.

[0042]

EXAMPLES The present invention will be described below in more detail with reference to Examples and Comparative Examples, but the present invention is not limited thereto. In addition, the test and evaluation of the characteristic of the film for fruit and vegetables packaging in an Example and a comparative example were implemented by the following method.

<Evaluation of Various Characteristics of Fruit and Vegetable Packaging Film> Light transmittance and haze (haze); ASTM-D100
Measured according to 3. Gas permeability: Measured for oxygen and carbon dioxide according to the method A of JIS-K-7126 "Test method for gas permeability of plastic films and sheets". Moisture Permeability: Measured in accordance with JIS-Z-0208 "Method for Testing Moisture Permeability of Moisture-Proof Packaging Material" Condition B.

Low temperature anti-fogging property; inclination 10 degrees, diameter 7.6 cm
Using a water bath having a skylight, a film sample was fixed to the skylight of the water bath.
The sample was allowed to stand for 2 days at a temperature of 15 ° C. and a water temperature of 15 ° C., and the antifogging property of the surface of the sample on the water bath side was visually determined based on a five-point standard, and the low-temperature antifogging property was evaluated. The larger the five-step number,
Excellent low-temperature anti-fog properties. Low-temperature anti-fog evaluation criteria Evaluation 5: Form a uniform water film without adhesion of water droplets. Evaluation 4: Adhesion of water droplets is less than 15%. Evaluation 3: Adhesion of water droplets is less than 40%. Evaluation 2: Adhesion of water droplets is less than 65%. Evaluation 1: Adhesion of water droplets is 65% or more.

<Evaluation of Fruit and Vegetable Freshness Preservation> Using the various films obtained in Examples and Comparative Examples, a heat-sealed three-sided bag for packing fruits and vegetables of 200 mm in width and 300 mm in length was used. Were separately placed in 200 g each, sealed by heat sealing, and then stored at 10 ° C., and the following four items (1) to (4) were evaluated. (1). Date of occurrence of decay: The day when rot began to occur on a part of the fruits and vegetables after storage was started was regarded as the date of occurrence of decay. When no rot was observed even after 15 days from the storage, it was determined as "none".

(2). Off-flavor generation date;
Each of the packaging bags after 6, 9, 12, and 15 days was opened, and the day on which an unusual odor was felt was regarded as the off-odor occurrence day. After storage 1
When no decay was observed even after 5 days, it was determined as "none". (3). Gas concentration in bag; The oxygen concentration and carbon dioxide concentration inside the packaging bag after 6 days from the start of storage are determined by PBI Da.
The measurement was performed using CheckMate 9900 manufactured by nsensor.

(4) Transparency: After 6 days of storage, the inside of the packaging bag was observed from the outside of the packaging bag, and the transparency was evaluated according to the following criteria. The fact that the fruits and vegetables inside the packaging bag are clearly visible is an important function of the fruits and vegetables packaging film because the freshness and the deterioration state of the fruits and vegetables can be confirmed. A: Condensation water forms a water film on the inner surface of the packaging bag, and fruits and vegetables inside the packaging bag are clearly visible. ：: Water drops are partially formed on the inner surface of the packaging bag, but fruits and vegetables inside the packaging bag can be identified. Δ: The inside of the packaging bag becomes cloudy due to condensation and fruits and vegetables inside the packaging bag are difficult to see. ×: Fruits and vegetables inside the packaging bag are hardly visible.

Examples 1-3 Melt flow rate (190 ° C., 21.18 N) = 1.
Ethylene-octene copolymer resin (trade name: Affinity PL1) having a density of 0.908 g / cm ³ at 0 g / 10 min.
840, manufactured by Dow Chemical Japan Co., Ltd.) and mixed with 2.0% by weight of polyoxyethylene stearylamine monostearate as an anti-fogging agent at 40 mm.
The mixture was melt-kneaded with an extruder and extruded into a film from a T-die to form a molten film. Next, the molten film-like material, the depth, width and vertical and horizontal pitch of the concave portion are 0.05 mm, 1.0 mm,
Cooling by sandwiching between an iron embossing roll, which is 5 mm, and a convex-concave shape having a square convex shape arranged in the machine direction (MD) of the roll surface, and a rubber roll coated with a Teflon (registered trademark) tube. The product was solidified to obtain a fruit and vegetable packaging film having a recess thickness of 0.01, 0.03, and 0.05 mm, respectively, and a basis weight of 25, 43, and 62 g / m ² , respectively.

Example 4 Example 4 was carried out in the same manner as in Example 2 except that diglycerin monostearate was used instead of polyoxyethylene stearylamine monostearate as an antifogging agent.

Comparative Examples 1 to 3 The same procedures as in Example 1 were carried out except that a mirror-made iron roll was used instead of the embossing roll.
8, 0.068 mm and the basis weight is 25,
43, 62 g / m ² of fruit and vegetable packaging film was obtained.

Comparative Example 4 The same operation as in Comparative Example 2 was carried out except that diglycerin monostearate was used instead of polyoxyethylene stearylamine monostearate as the antifogging agent.

Examples 5 to 7 Melt flow rate (230 ° C., 21.18 N) = 1.
8 g / 10 min, density = 0.90 g / cm ³ ethylene-
Propylene copolymer resin (trade name: Chisso Polypro XF)
1800, manufactured by Chisso Co., Ltd.)
0 wt%, melt flow rate (230 ° C, 21.18
N) = 3.5 g / 10 min, hydrogenated styrene-butadiene copolymer rubber having a density = 0.89 g / cm ³ (trade name: DYNARON1320P, Nippon Synthetic Rubber Co., Ltd.)
A thermoplastic resin composition containing 20% by weight of polyoxyethylene stearylamine monostearate as an antifogging agent and 2.0% by weight of the antifogging agent is melt-kneaded by a 65 mm extruder, and extruded from a T-die into a film. A molten film was obtained.

Next, the depth, width and vertical and horizontal pitches of the recesses are 0.8 mm, 0.8 mm and 3 m, respectively.
m, which is cooled and solidified by being sandwiched between an iron embossing roll and a mirror-finished iron roll in which irregularities having a square convex shape are arranged in the machine direction of the roll surface, and heat having a basis weight of 670 g / m ² . A plastic resin sheet was used. After heating the obtained thermoplastic resin sheet so that the sheet temperature becomes 140 ° C., the longitudinal stretching ratio × the transverse stretching ratio is 3 × 4 times (area magnification 12 times) and 5 × 6 times (area magnification). 30 times), biaxially stretched under the conditions of 7 × 8 times (area magnification 56 times), and the recess thicknesses are 0.02 and 0.00, respectively.
8, 0.004 mm, and the basis weight is 5
7, 22, and 12 g / m ² of fruit and vegetable packaging films were obtained.

Comparative Examples 5 to 7 The same operation as in Example 5 was carried out except that a mirror-finished iron roll was used instead of the embossing roll.
For the case of biaxial stretching of 0 times, the thickness is 0.062,
0.024 mm with a basis weight of 57, 22 respectively
A g / m ² film for packaging fruits and vegetables was obtained. When the area magnification was 56 times, the film was frequently torn during stretching, and could not be stretched.

Example 8 The same operation as in Example 5 was carried out except that 6% by weight of calcium carbonate having an average particle size of 0.3 μm was added to the thermoplastic resin composition.

As shown in Tables 1 and 2, Examples 1 to 7
Is sufficient to satisfy the gas permeability required for MA packaging, and
Since the area of contact with fruits and vegetables was reduced, the occurrence of decay was dramatically improved.

[0057]

[Table 1]

[0058]

[Table 2]

[0059]

Industrial Applicability The fruit and vegetable packaging film of the present invention has a thermoplastic resin containing an anti-fogging agent having a specific uneven shape formed on at least one surface thereof and optionally monoaxially or biaxially stretched. It is a film made of a resin composition. This film not only has the gas permeability necessary for maintaining the freshness of the fruits and vegetables, but also can prevent the moisture evaporating from the fruits and vegetables from sticking to each other by being interposed between the fruits and vegetables and the film, so that the decay of the fruits and vegetables can be prevented. Suppression is possible. By using this film to package fruits and vegetables with the uneven surface facing the fruits and vegetables, it is possible to prevent the fruits and vegetables from rotting during the distribution stage and storage at home, and to maintain the freshness of the fruits and vegetables. It can greatly contribute.

[Brief description of the drawings]

FIG. 1 shows an example of a film for packaging fruits and vegetables of the present invention.

FIG. 2 shows an example of a concave shape when the fruit and vegetable packaging film of the present invention is viewed from above an uneven surface.

[Explanation of symbols]

 1... Recesses in the fruit and vegetable packaging film. 2... Protrusion of film for packaging fruits and vegetables. 3 ... width of the concave portion of the fruit and vegetable packaging film. 4: The pitch of the film for packaging fruits and vegetables. 5: Thickness of the convex part of the film for packaging fruits and vegetables. 6 ... thickness of the concave portion of the fruit and vegetable packaging film.

 ──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Takayuki Nishitani 5-1, Goi Kaigan, Ichihara City, Chiba Prefecture Chisso Petrochemical Co., Ltd. Processed Products Development Laboratory F term (reference) 3E067 AA11 AB09 BA17A BB14A BC04A CA03 CA11 GB01 GD01 3E086 AB01 BA02 BA15 BA44 BB01 BB90 CA17 CA18 DA03 3E096 BA27 CA11 CB02 EA04X FA08 GA01 4B069 AB04 HA09 KD07

Claims (4)

[Claims] An at least one surface of a film made of a thermoplastic resin composition containing an anti-fogging agent has an uneven shape formed of substantially continuous convex portions and discontinuous concave portions partitioned by the convex portions. Wherein the uneven shape satisfies the following condition. 1) A thickness d _a is 0.003~0.05mm recess, the ratio d _a / d _b of thickness d _a of the concave portion to the thickness d _b of the projecting portion
Is 0.05 ≦ d _a / d _b ≦ 0.8. 2) The ratio S _a / S _b of the concave area S _a and the convex area S _{b on} the surface of the film on which the irregularities are formed is 0.1 ≦ _Sa /
S _b ≦ 5. 2. The film for packaging fruits and vegetables according to claim 1, wherein the light transmittance of the film having the unevenness is 80 to 99% and the haze value is 1 to 10%. 3. The thermoplastic resin is a polypropylene resin or a polyethylene resin, and has an oxygen permeability of 1,5.
00 to 30,000 nmol / m ² · s · 100 kP
a, Carbon dioxide permeability is 6,000-120,000n
^{mol / m 2 · s · 100kPa} , 40 fruits and vegetables packaging film according to claim 1 or 2, wherein the moisture permeability is 10 to 200 g / m ² · 24h at ° C.. 4. The packaging for fruits and vegetables according to claim 1, wherein the thermoplastic resin film having the uneven shape is a stretched film stretched at an area magnification of 4 to 60 times. the film.