JPH06286773A - Freshness preserving film and manufacture thereof - Google Patents

Abstract

PURPOSE:To provide a freshness preserving film which does not allow bacteria and miscellaneous germs to transmit, can control permeable amounts of oxygen gas, carbon dioxide gas and vapor and also can adsorb gas such as vapor and ethylene. CONSTITUTION:A freshness preserving film comprises an organic resin film 160, two or more kinds of numerous ceramic particles 165,168 having different hardness dispersed on the film 160, numerous recesses 167 formed on the film 160 having fine opening width and a remaining thin film 171 formed on a part of the film 160 located at a bottom of the recess 167. At least ceramic particles 165 having higher hardness of the ceramic particles has adsorbing ability for high gas and vapor, while numerous hair cracks 169 through the remaining thin film 171 are formed in the vicinity of the ceramic particles 168 having lower hardness dispersed on the remaining thin film 171.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a freshness keeping film and a method for producing the same.

[0002]

2. Description of the Related Art Generally, a modified atmosphere (MA; Modified Atomosphere) is used for keeping freshness of fruits and vegetables.
re) placing fruits and vegetables in a controlled atmosphere (C
A; Controlled Atomosphere
It is known to put vegetables and fruits in e). In the former method, when the fruits and vegetables are hermetically wrapped with a plastic film, the oxygen concentration in the packaging material decreases and the carbon dioxide concentration increases due to the breathing action of the fruits and vegetables themselves, so the oxygen content decreases and the carbon dioxide concentration increases. Thus, the respiration of the fruits and vegetables is suppressed and the freshness of the fruits and vegetables is maintained. The latter method controls the growth (deterioration) of the fruits and vegetables by controlling the amount of oxygen permeated from the outside through the packaging material into the inside and the amount of carbon dioxide gas that the stored fruits and vegetables breathe out. It delays and maintains the freshness of fruits and vegetables. Furthermore, the freshness-keeping film is required to have a structure in which water vapor evaporated from fruits and vegetables is transmitted or adsorbed to prevent dew condensation on the surface of the film which causes decay.

By the way, as a conventional freshness-keeping film, there is known a polyethylene film in which Oya stone, zeolite and coral stone are dispersed. This freshness-maintaining film mainly aims at the MA effect, and easily gives the CA effect. However, the freshness-keeping film does not have a sufficient CA effect even if the gas permeability is slightly higher than that of the polyethylene film. Further, most of the particles such as Otani stone are dispersed in the film, and only a few are exposed on the surface, so that there is a problem that the water adsorption effect is poor.

Recently, a P-Plus film aiming at the CA effect has been known as a freshness keeping film. This film was developed in the UK and is to be sold daily by Sumitomo Bakelite.The gas permeation rate suitable for the fruits and vegetables to be packaged is calculated in advance, and laser irradiation is applied to an organic resin film such as polyethylene film. This is a through hole having a diameter of the order of several μm. However, the P-Plus film is not only slightly controlled in the amount of permeation of water vapor, but also has no function of adsorbing water vapor or the like. Therefore, if water vapor is generated when the fruits and vegetables are hermetically packaged in the film, the water vapor may condense on the surface of the film, and the portions of the fruits and vegetables that come into contact with the dew drops may rot.

On the other hand, there is known an antifogging film in which a surfactant is applied to the surface of an organic resin film such as a biaxially oriented polypropylene film or a surfactant is kneaded therein. This film is used for open packaging of fruits and vegetables, and allows water vapor evaporated from the fruits and vegetables to flow down on the surface of the packaging agent without dew condensation. However, the anti-fogging film merely prevents the occurrence of dew condensation, and water drops flow down and accumulate at the bottom of the packaging material. Therefore, fruits and vegetables come into contact with the water drops and putrefaction occurs at the contact points. Further, the antifogging film cannot expect the CA effect.

[0006]

The object of the present invention is to prevent the permeation of bacteria and germs, to control the permeation amount of oxygen gas, carbon dioxide gas and water vapor, and to adsorb the gas such as water vapor and ethylene. And a freshness-keeping film. Another object of the present invention is to provide a method capable of producing the freshness-keeping film having the above-mentioned excellent properties with good reproducibility and in mass production.

[0007]

The freshness-keeping film according to the present invention comprises an organic resin film, a large number of two or more kinds of ceramic particles having different hardnesses dispersed in the film, and a large number of particles formed on the film. A recess having a fine opening width, and a residual thin film portion formed in the film portion located at the bottom of the recess,

At least the ceramic particles having high hardness among the ceramic particles have high gas and water vapor adsorption properties and penetrate the residual thin film around the low hardness ceramic particles dispersed in the residual thin film portion. It is characterized in that a large number of hair cracks are formed. The organic resin film preferably has a thickness of 5 μm to 3 mm.

Examples of the organic resin include polyolefin such as polyethylene and polypropylene, polyester such as polyethylene terephthalate, polyvinyl chloride, ethylene-vinyl acetate copolymer, fluororesin, polyamide, polycarbonate, polyimide, polyether ether ketone, Polyetherketone, elastomer,
Examples thereof include polyurethane and a mixed resin of two or more selected from these resins.

Examples of the ceramic particles include zeolite particles, Otani stone particles, coral stone particles, diatomaceous earth particles and the like. Among these ceramic particles, zeolite particles have higher hardness than other ceramic particles,
It also has high gas and moisture adsorption. Further, the diatomaceous earth particles have considerably lower hardness than the zeolite particles, and have high gas and water vapor adsorption properties similar to the zeolite particles. Examples of the two or more kinds of ceramic particles having different hardness include a combination of zeolite particles and at least one kind of particles selected from the group of Otani stone particles, coral stone particles and diatomaceous earth particles.

The ceramic particles are required to have a particle size smaller than the thickness of the organic resin film, and may be appropriately selected according to the thickness of the organic resin film. Specifically, among the ceramic particles, ceramic particles having high hardness have an average particle diameter of 0.1 to 30 μm, and ceramic particles having low hardness have a particle diameter of 0.1 to 10 μm.
It is preferred to have an average particle size of μm.

The amount of the ceramic particles dispersed in the organic resin film is preferably 0.1 to 3% by weight, more preferably 0.2 to 0.5% by weight. This is due to the following reasons. When the amount of the ceramic particles dispersed is less than 0.1% by weight, it becomes difficult to impart water adsorption and to form hair cracks in the residual thin film portion. On the other hand, if the amount of the ceramic particles dispersed exceeds 3% by weight, the original properties of the film, such as transparency, strength, and soft feel, may be impaired.

The mixing ratio of the ceramic particles having different hardnesses is such that the ceramic particles (A) having a high hardness and a high adsorbability of gas and water and the ceramic particles (B) having a low hardness are used.
In that case, it is preferable to set the range of A: B = 1: 9 to 8: 2. If the ratio of the ceramic particles having high hardness and water adsorption is less than 1, it becomes difficult to obtain a freshness-keeping film having good gas and water adsorption. On the other hand, when the ratio of the ceramic particles having a high hardness and a high gas and moisture adsorption property exceeds 8, the ratio of the ceramic particles having a low hardness relatively decreases to form a large number of hair cracks in the remaining thin film portion. It becomes difficult, and it becomes difficult to obtain a freshness-keeping film in which the permeation amount of gas and water vapor is controlled.

The opening width of the concave portion formed in the organic resin film is 0.5 depending on the use of the freshness keeping film.
It is arbitrarily selected within the range of 150 μm. It is preferable that the plurality of recesses have the same opening width.

The number of the recesses formed in the organic resin film is 1 cm ² depending on the relationship with the opening width of the recesses and the use of the freshness keeping film. 50 to 200,0 per
It is arbitrarily selected in the range of 00. It is desirable that the large number of recessed holes be uniformly dispersed in the organic resin film.

It is desirable that the thickness of the remaining thin film portion of the organic resin film located at the bottom of the recess is arbitrarily selected within the range of 15 μm or less, more preferably 10 μm, depending on the use of the freshness maintaining film.

In the method for producing a freshness-keeping film according to the present invention, a large number of ceramic particles having different hardness are kneaded and dispersed in an organic resin, and a film is formed to obtain a long organic resin in which the ceramic particles are dispersed. Forming a film;

While rotating a first roll having a large number of particles having a Mohs hardness of 5 or more having sharp corners attached to the surface and a second roll having a smooth surface in opposite directions, the first and second rolls are rotated. While passing the long organic resin film in between, by applying a constant pressure to the film passing between the rolls so as to be uniform over the entire film surface in contact with the rolls, the first The film which is located between the sharp corners of the particles and the second roll at the same time by making the long organic film bite the sharp corners of the particles on the roll surface to form a large number of fine recesses. A step of crushing low hardness ceramic particles dispersed in a portion to form a large number of hair cracks around the crushed ceramic particles;

The ceramic particles need to have a particle size smaller than the thickness of the organic resin film, and may be appropriately selected according to the thickness of the organic resin film. Specifically, the ceramic particles having a high hardness among the ceramic particles have an average particle diameter of 0.1 to 30 μm, and the ceramic particles having a low hardness crushed in the recess forming step have a particle diameter of 0.1 to 0.1 μm. It is preferred to have an average particle size of 30 μm.

The first roll has a structure in which a large number of particles having a Mohs hardness of 5 or more having sharp corners on the surface of a metal roll body are electrodeposited or attached by an organic or inorganic binder. Examples of the particles having a Mohs hardness of 5 or more include cemented carbide particles such as tung ten carbide, silicon carbide particles, boron carbide particles, sapphire particles, cubic boron nitride (cBN) particles, natural or synthetic diamond particles, and the like. Can be mentioned. In particular,
Synthetic or natural diamond particles having characteristics such as hardness and strength are desirable. The particles have a particle size of 5 to 5.
It is desirable to use one having a particle size variation of 5% or less at 350 μm. The large number of particles has a concave portion of 1 cm ^{2 in the} long organic resin film. 50 to 200,000 per
From the viewpoint of forming zero rolls, it is desirable to deposit 50% or more on the surface of the roll body.

As the second roll, for example, an iron roll, an iron-based alloy roll, an iron roll whose surface is subjected to Ni plating or Cr plating, a stainless steel roll, or a metal roll main body is coated with a polymer resin layer on the surface thereof. What was done can be used. As the polymer resin, various resins can be used, but urethane resin, silicone rubber, fluorine rubber, etc., which have a high buffering effect on the long organic resin film, are particularly preferable.

In the step of forming the recesses in the long organic resin film, a low hardness ceramic dispersed in the film portion located between the sharp roll of the Mohs hardness of 5 or more and the second roll. Although the particles are crushed to form a large number of hair cracks around the particles, the high-hardness ceramic particles dispersed in the film are not crushed and the original shape is maintained.

[0023]

The freshness keeping film according to the present invention comprises an organic resin film such as polyethylene or polypropylene,
A large number of two or more kinds of ceramic particles having different hardnesses dispersed in the film, a large number of concave portions having a fine opening width formed in the film, and a residue formed in the film portion located at the bottom of the concave portion. And a thin film part,
At least high hardness ceramic particles among the ceramic particles have high gas and water vapor adsorption, and a large number of hairs penetrating the residual thin film are provided around the low hardness ceramic particles dispersed in the residual thin film portion. The structure has cracks.

When the fruits and vegetables are hermetically packaged with the freshness-keeping film having such a structure, the residual remains around the low-hardness ceramic particles dispersed in the residual thin film portion of the organic resin film located at the bottom of the recesses. Since many hair cracks penetrating the thin film portion are formed, the amount of oxygen gas permeated from the outside in the remaining thin film portion, the amount of carbon dioxide gas generated from the fruits and vegetables and the water vapor evaporated from the fruits and vegetables. The amount of transmission can be controlled. As a result, the above-mentioned CA effect, that is, the growth (deterioration) of the fruits and vegetables can be delayed to maintain the freshness of the fruits and vegetables.

Further, the amount of water vapor permeated from the fruits and vegetables can be controlled by the remaining thin film portion of the organic resin film in which the many hair cracks are formed. Moreover, due to the low hardness ceramic particles dispersed around the hair crack and the ceramic particle having high hardness and high gas and moisture adsorbability, through the many cracks formed in the film and the hair crack of the remaining thin film portion. Water vapor and gases such as ethylene that are permeated can be adsorbed. As a result, by controlling the amount of water vapor permeation and adsorbing gas with water vapor or ethylene, when the fruits and vegetables are hermetically packaged, the water vapor evaporated from the fruits and vegetables can escape to the outside or be adsorbed by the packaging material itself, so that the packaging material surface It is possible to prevent the occurrence of dew condensation and prevent the fruits and vegetables from decaying due to contact with water drops.

Therefore, according to the freshness-keeping film of the present invention, the freshness of fruits and vegetables can be maintained by the above-mentioned CA effect, and the occurrence of dew condensation can be prevented to prevent the spoilage due to the contact of the fruits and vegetables with water droplets. Produces the effect of (1) Since the permeation amount of water vapor can be controlled and it has a function of adsorbing, antifogging processing is not required. (2) Since the amount of gas permeation is controlled not by through holes but by hair cracks, invasion of bacteria and miscellaneous bacteria can be completely eliminated. (3) Since the permeation amount of gas and water vapor can be controlled over the entire surface of the film, the size and shape of the hermetically-sealed packaging material can be arbitrarily set when the sealed packaging material is manufactured.

(4) When the amount of the ceramic particles dispersed in the organic resin film is regulated within the range of 0.1 to 3% by weight, the original characteristics of the organic resin film, such as transparency, softness and strength, can be maintained. It is possible to maintain the freshness of fruits and vegetables without damaging them.

According to the method for producing a freshness-keeping film according to the present invention, a large number of ceramic particles having different hardness are kneaded and dispersed in an organic resin and then formed into a film to form a long organic material in which the ceramic particles are dispersed. Form a resin film,
While rotating a first roll having a large number of particles having a Mohs hardness of 5 or more having sharp corners adhered to the surface and a second roll having a smooth surface in the opposite directions, the first roll and the second roll are separated from each other. While passing a long organic resin film, by applying a constant pressure to the film passing between the rolls so as to be uniform over the entire film surface in contact with the rolls, the first roll surface The sharp corners of a large number of particles can be eaten into the long organic film to form a large number of fine recesses, and at the same time, the film corners located between the sharp corners of the particles and the second roll can be formed. The dispersed low hardness ceramic particles can be crushed to form many hair cracks around them. However, the ceramic particles having high hardness dispersed in the film located between the sharp corners of the particles and the second roll are not substantially crushed and the original shape is maintained. As a result, the freshness-keeping film having the above-described function can be manufactured with good reproducibility and in mass production.

[0029]

Embodiments of the present invention will now be described in detail with reference to the drawings.

FIG. 1 is a front view showing a manufacturing apparatus of a freshness-keeping film used in this embodiment, FIG. 2 is a side view showing a main part of the manufacturing apparatus of FIG. 1, and FIG. 3 is a III-III line of FIG. 4 is a front view for explaining an operation of forming a concave portion on a long organic resin film by a freshness-keeping film manufacturing apparatus, and FIG. 5 is an enlarged main part of a first roll in the manufacturing apparatus of FIG. 1. FIG.

Reference numeral 101 in the drawing is a bed. A table 102 is provided on the upper surface of the bed 101 except near the right end. Two key-shaped frames 103 are installed on the table 102 at predetermined intervals in the width direction of the table 102. The frame 103 includes a lower plate 103a, side plates 103b and an upper plate 1.
It is formed from 03c. First bearings 104 are built in the middle of the side plates 103b of each frame 103.
The boxes 105 are fixed. A first roll 106 is arranged between the frames 103. As shown in FIGS. 2 and 5, the first roll 106 has, for example, a large number of particles with a Mohs hardness of 5 or more (for example, synthetic diamond particles) 107 having a grain size of 40 to 60 μm and sharp corners at 70% or more on the surface. Electrodeposition layer 10 with area ratio
It is composed of an iron roll main body 108 attached via 8a, and a shaft 109 penetrating the center of the main body 108 and protruding from both end surfaces of the main body 108. Both protruding ends of the shaft 109 are respectively supported by bearings 104 in the first box 105. A shaft 109 on one end side (for example, a left end side) of the first roll 106 penetrates the box 105, and a gear 111 that meshes with a gear of a drive shaft of a motor (not shown) is provided on a protruding portion of the shaft 109. It is pivoted. Therefore, the first roll 106 is rotated in the clockwise direction, for example, by driving the motor. Also, the gear 11
A gear 110 is mounted on the protruding portion of the shaft 109 located between the left side surface of the box 105 and the left side of the box 105.

Rails 112 and 113 are formed on the side plates 103b of the frames 103 located below and above the first box 105, respectively.
As shown in FIG. 3, sliders 114 (the other slider is not shown) are vertically movably arranged on the lower rails 112, respectively. Each slider 11
Second boxes 116 each having a bearing 115 built therein are fixed to the shafts 4, and can be vertically moved along the rails 112. A second roll 117 is disposed between the frames 103 so as to face the first roll 106 below the first roll 106. The second roll 117 is composed of a roll main body 118 having a hard surface made of, for example, stainless steel, and a shaft 119 penetrating the center of the main body 118 and protruding from both end surfaces of the main body 118. Both protruding ends of the shaft 119 are axially supported by bearings 115 in the second box 116. One end side of the second roll 117 (for example, the left end side)
Of the shaft 119 protrudes through the second box 116, and a gear 120 that meshes with the gear 110 of the shaft 109 of the first roll 106 is mounted on the protruding portion of the shaft 119. . Therefore, the second roll 117 may include the second box 116 and the slider 1.
It is arranged by 14 so as to be vertically movable along the rail 112. The first roll 106 is driven by the motor.
By rotating the shaft 109 of the shaft 109 in the clockwise direction, the shaft 119 having the gear 120 meshing with the gear 110 of the shaft 109 rotates in the counterclockwise direction, and as a result, the second roll 117 is rotated counterclockwise. It is designed to rotate in a clockwise direction.

As shown in FIG. 3, sliders 121 (the other slider is not shown) are vertically movably arranged on the upper rails 113, respectively. A third box 123 having a bearing 122 built therein is fixed to each of the sliders 121, and can be moved up and down along the rails 113. In addition, the third roll 124 is provided between the respective frames 103, and the first roll 10
6 are arranged so as to face each other. The third roll 124 is an iron roll body 1 whose surface is coated with a polymer resin layer 125 such as urethane resin.
26 and the main body 12 through the center of the main body 126.
6 and shafts 127 projecting from both end surfaces thereof. Both protruding ends of the shaft 127 are axially supported by the bearings 122 in the third box 123. The shaft 12 on one end side (for example, the left end side) of the third roll 124
The seventh portion protrudes through the third box 123, and a gear 128 that meshes with the gear 110 of the shaft 109 of the first roll 106 is attached to the protruding portion of the shaft 127. Therefore, the third roll 124 is vertically movably arranged along the rail 113 by the third box 123 and the slider 121. Further, the shaft 109 of the first roll 106 is driven by the motor.
By rotating the shaft 109 clockwise,
Shaft 127 having said gear 128 meshing with said gear 110 rotates counterclockwise, resulting in said third gear
The roll 124 is adapted to rotate counterclockwise.

The two frames 103, the two first boxes 105, the first roll 106, the two sliders 112 and 113, the two second boxes 116, the second roll 117, and the two second rolls. The three boxes 123 and the third roll 124 constitute a recess forming unit 129.

The lower wall of the two second boxes 116 has a cylindrical body 13 having upper and lower flanges 130 and 131.
2 are arranged respectively. Each of the cylindrical bodies 132 is
As shown in FIG. 3, from the upper flange 130 to the second
A plurality of screws 133 screwed to the lower wall of the box 116 are fixed to the second box 116. A disc 135 having a hole 134 in the center thereof is disposed on the lower flange 131 of each of the cylindrical bodies 132,
Further, each of the discs 135 is fixed by a plurality of screws 136 screwed to the lower flange 131 from each of the discs 135. A coil spring 137 is housed in each of the cylindrical bodies 132 so as to apply an elastic force in the vertical direction. A rod 139 having a pressure sensor 138 attached to the upper end thereof is inserted into each of the cylindrical bodies 132 through a hole 134 of the disc 135.
The pressure sensors 138 are in contact with the lower ends of the coil springs 137, and can detect the pressing force applied to the coil springs 137 due to the rise of the rods 139. A disk-shaped guide 140 for smoothly moving the rod 139 up and down is attached to the rod 139 portion below each sensor 138. A ball screw 14 is attached to the lower end of each rod 139.
1 is inserted respectively. Each ball screw 1
41 penetrates the lower plate 103a of the frame 103 and projects into the recesses (not shown) of the bed 102. A casing (the other casing is not shown) 142 having a threaded engagement plate (not shown) is provided in each of the recesses. A lower end protruding portion of the ball screw 141 is screwed into the engagement plate in each casing 142. Worm shafts (not shown) that engage with the lower end protrusions of the ball screws 141 are inserted into the respective casings 142 from the horizontal direction, and a handle is provided at one end of each worm shaft (the other handle is a (Not shown) 143 are provided respectively. Therefore, when the handle 143 is rotated, the ball screw 141 engaging with the worm shaft of the handle 143 is rotated, and the rod 139 having the ball screw 141 inserted therein is moved up (or down). ing. In this case, when the rod 139 is lowered by a certain distance or more, the disc-shaped guide 140 attached to the rod 139 comes into contact with the inner surface of the disc 135 below the cylindrical body 132 to lower the cylindrical body 132 itself. Let Therefore, the second box 116 fixed to the upper end of the cylindrical body 132 is lowered by the slider 114 along the lower portion 112 of the rail.

The two cylindrical bodies 132, the two discs 135, the two coil springs 137, the two pressure sensors 138, the two rods 139, the two discoid guides 140, and the two ball screws. 14
1, the two casings 142, the two worm shafts (not shown), and the two handles 143 apply a pressing force to the long organic resin film passing between the first and second rolls 106 and 117. The first pressure adjusting means 144 for adjusting is configured.

A cylindrical body 14 having upper and lower flanges 145 and 146 is provided on the upper walls of the two third boxes 123.
7 are arranged respectively. Each of the cylindrical bodies 147 is
As shown in FIG. 3, from the lower flange 146 to the third
The plurality of screws 148 screwed to the upper wall of the box 123 are fixed to the third box 123. On the upper flange 145 of each of the cylinders 147, there is arranged a disc 150 having a hole 149 in the center,
In addition, each of the disks 150 is fixed by a plurality of screws 151 screwed from the disks 150 to the upper flange 145. A coil spring 152 is housed in each of the cylindrical bodies 147 so as to apply an elastic force in the vertical direction, and the lower end of each coil spring 152 is brought into contact with the upper wall of the third box 123. There is. A rod 154 having a pressure sensor 153 attached to the lower end thereof is provided in each of the cylindrical bodies 147.
It is inserted through 50 holes 149. The pressure sensors 153 are in contact with the upper ends of the coil springs 152, and the coil springs 152 are moved by lowering the rods 154.
It is possible to detect the pressing force to. A disc-shaped guide 155 for smoothly moving the rod 154 up and down is provided on the rod 154 above the sensors 153.
Are attached respectively. Ball screws 156 are inserted into the upper ends of the rods 154, respectively. Each of the ball screws 156 penetrates the upper plate 103c of the frame 103 and passes through the upper plate 103c.
Projecting above. On the upper surface of each of the upper plates 103c, a casing (the other casing is not shown) 157 in which a threaded engagement plate (not shown) is incorporated is provided. The upper end protruding portion of the ball screw 156 is screwed into the engagement plate in each casing 157. Worm shafts (not shown) that engage with the upper end protrusions of the ball screws 156 are respectively inserted into the casings 157 from the horizontal direction, and a handle is provided at one end of each worm shaft (the other handle is a (Not shown) 158 are provided respectively. Therefore, when the handle 158 is rotated, the ball screw 156 engaging with the worm shaft of the handle 158 is rotated, and the ball screw 15 is rotated.
6 descends (or ascends) the rod 154 with the inserted 6
It is supposed to do. In this case, when the rod 154 is raised above a certain distance, the disc-shaped guide 155 attached to the rod 154 causes the cylindrical body 147 to move.
The cylindrical body 147 itself is raised by contacting the inner surface of the upper disk 150. Therefore, the third box 123 fixed to the lower end of the cylindrical body 147 is attached to the slider 12.
1 raises along the rail 113.

The two cylindrical bodies 147, the two discs 150, the two coil springs 152, the two pressure sensors 153, the two rods 154, the two discoid guides 155, and the two ball screws. 15
6, by the two casings 157, the two worm shafts (not shown) and the two handles 158, the pressing force to the long organic resin film passing between the first and third rolls 106 and 124 is applied. The second pressure adjusting means 159 for adjusting is configured.

A winding roll (not shown) of a long organic resin film is provided in front of the recess forming unit 129.
The long organic resin film 160 of the winding roll is disposed between the first and second rolls 106 and 117 of the unit 129 and between the first and third rolls via two feed rolls 161. It is supplied between 106 and 124. In the subsequent stage of the unit 129, static electricity removing means 16
2 are arranged. The static electricity removing means 162 is installed on the table 102 and holds a container 16 containing pure water.
3 and an ultrasonic wave generation member (not shown) for applying ultrasonic waves to the pure water. Unit 1
In order to convey the long organic resin film that has passed between the first and third rolls 106 and 124 between 29 and the static electricity removing means 162, inside the container 163 and at the subsequent stage of the container 163. 5 of the feed rolls 161 are arranged. It should be noted that the contact roll 1 is attached to the two feed rolls 161 located at the front and rear stages of the container 163.
64 are arranged respectively. The static electricity removing means 16
In the subsequent stage of 2, a plurality of hot air jetting members for drying the long organic resin film that has passed between the feed roll 161 and the reliance roll 164 and a winding roll (all not shown) are sequentially arranged. Has been done. Example 1

The first and second recess forming units 129 in the freshness keeping film manufacturing apparatus having the above-described structure.
A method for producing a freshness-keeping film by forming recesses in a long organic resin film made of low-density polyethylene having a thickness of 30 μm in which zeolite particles and Otaniishi particles described later are dispersed between rolls 106 and 117 is shown in FIG. 4 and 6
~ It demonstrates with reference to FIG.

First, linear low density polyethylene (LLDP
E) Otaniishi particles having an average particle size of 15 μm and an average particle size of 1
As shown in FIG. 6, zeolite particles 165 and Otaniishi were formed by adding 5 μm of zeolite particles (mixing weight ratio 2: 8) in a total amount of 0.5% by weight, kneading and dispersing, and then forming a film by an inflation method. A long organic resin film 160 having a thickness of 30 μm in which the particles 166 were dispersed was produced. Subsequently, the long organic resin film 160
Was wound into a wound roll.

Next, the two handles 14 of the first pressure adjusting means 144 in the manufacturing apparatus having the structure shown in FIGS.
For example, by rotating 3 in the counterclockwise direction,
Each second box 116 of the recess forming unit 129 connected to the upper end of each cylindrical body 132 is moved down along each rail 112 of each frame 103 by the slider 114, so that the bearing 115 in each second box 116 can be moved. The second roll 117 supported by the shaft is attached to the first roll 10 thereon.
Keep sufficient distance from 6. Further, by rotating the two handles 158 of the second pressure adjusting means 159, for example, in the clockwise direction, the respective third boxes 123 connected to the lower ends of the respective cylindrical bodies 147 are moved by the sliders 121 to the rails 113 of the respective frames 103. Respectively, and the third roll 124 pivotally supported by the bearing 122 in each of the third boxes 123 is lifted along the first roll 10 underneath.
Keep sufficient distance from 6. In this state, a long organic resin film 160 having a thickness of 30 μm made of PPDPE having a thickness of 30 μm in which zeolite particles and Otaniishi particles are dispersed from the above-mentioned winding roll is supplied to the unit 129 by the two feed rolls 161. After passing between the first and second rolls 106 and 117, between the feed roll 161, and between the first and third rolls 106 and 124, the four feed rolls 161 pass through the inside of the container 163 of the electrostatic elimination means 162. Then, the tip of the long organic resin film 160 is wound around a winding roll (not shown). In addition,
In the step, the long film 160 is formed into the first,
When passing between the third rolls 106 and 124, the long organic resin film 160 is prevented from coming into contact with the surface of the first roll 106 as shown in FIG.

Then, after the leading end of the long film 160 is wound on a winding roll, the first pressure adjusting means 14 is used.
By rotating the two handles 143 of No. 4 in the clockwise direction, the second handles connected to the upper ends of the cylindrical bodies 132
Box 116 with slider 114 for each frame 1
No. 2 of each of the second boxes 116, which are respectively supported by the bearings 115 in the second boxes 116.
The roll 117 is brought into contact with the first roll 106 thereon. Further, by rotating the respective handles 143 in the same direction, the respective coil springs 137 thereon are compressed by the respective sensors 138 at the upper ends of the respective rods 139. Due to the compression of each coil spring 137, a pressing force is applied to the lower wall of each second box 116, and the second roll 11 pivotally supported by the bearing 115 in the second box 116.
7 and the pressing force between the first roll 106 increase. At this time, the pressure sensor 138 causes the second roll 11 to move.
7 and the first roll 106, the pressing force (compressing force) is detected, and the rotation of each of the handles 143 is adjusted in the forward and reverse directions, whereby the second and first rolls 117 and 106 are adjusted.
The pressing force on the long film 160 located between them is adjusted. By the pressing adjustment of the unit 129 by the first pressure adjusting means 144, a constant pressing is performed over the entire width direction of the long film 160 located between the second and first rolls 117 and 106. Pressure (eg 1
00 kg / m) is applied, and the preparation for the recess forming operation is completed.

After the preparation for the recess forming operation is completed, ultrasonic waves are applied to the pure water contained in the container 163 of the static electricity removing means 162 by an ultrasonic wave generating member (not shown). Next, by rotating the winding roll and the drive shaft of a motor (not shown) at the same time, the gear of the drive shaft and the gear 1 of the shaft 109 of the first roll 106 are rotated.
By the rotation transmission of 11, the first roll 106 is rotated in the clockwise direction. When the first roll 106 rotates, the gear 110 of the shaft 109 and the second roll 117
The second roll 117 is rotated counterclockwise by the rotation transmission of the gear 120 of the shaft 119. In this case, since the third roll 124 is disposed above the first roll 106 with sufficient separation, the third roll 1
24 and the gear 128 of the shaft 127 and the first roll 1
The meshing of the gear 110 of the shaft 109 in 06 is released,
The third roll 124 is not driven by the rotation of the motor and is free to rotate. By thus rotating the first and second rolls 106 and 117, the long film 1 passing between the rolls 106 and 117 is obtained.
A recess is formed in 60.

That is, the first roll 106 has a grain size of 40 to 60 having sharp corners as shown in FIGS.
A large number of synthetic diamond particles 107 of μm 70
The structure is provided with the iron roll main body 108 attached via the electrodeposition layer 108a at an area ratio of at least%. The second roll 117 has a structure including a roll body 118 having a hard surface such as stainless steel. Therefore, when the long organic resin film 160 passes between the first and second rolls 106 and 117, as shown in FIG. 7, many synthetic diamond particles 107 on the surface of the first roll 106 are sharp. The corners were uniformly bite into the long organic resin film 160 for mechanical perforation, and a large number of recesses 167 having an inverted conical shape were formed. At the same time, Otani stone particles 166 with low hardness dispersed in the film 160 portion located between the synthetic diamond particles 107 and the second roll 117 are crushed, and a large number of hair cracks around the crushed pieces 168. 169 was formed. However, the film 160
The high hardness zeolite particles 165 dispersed therein were not substantially crushed and the shape was maintained as it was.

Then, the long organic resin film (long freshness-keeping film) 170 in which the recesses and the hair cracks have been formed by the unit 129 is moved by the five feed rolls 161 and the two contact rolls 164 to remove the static electricity. It passes through and is conveyed in the container 163 of 162. The long organic resin film 1 by the unit 129
The formation of the concave portion in 60 is performed by the first and second rolls 106,
Since the friction of 117 is the main component, a large amount of static electricity is generated on the surface of the long freshness-keeping film 170 after the recess forming process, and the surrounding dust is attached. The long freshness-keeping film 170 after the recess forming process is passed through a container 163 of the static electricity removing means 162 in which pure water is stored, and ultrasonic waves are applied to the pure water by an ultrasonic wave generation member (not shown). The dust adhering to the long freshness maintaining film 170 is washed away. Subsequently, the long freshness-keeping film 170 is passed through a plurality of hot air jetting members (not shown) to volatilize and remove water on the surface, and then the film is wound up on a winding roll (not shown).

As shown in FIG. 8, the long freshness-keeping film 170 manufactured by the method of the first embodiment as described above has an average opening in the long organic resin film 160 made of low-density polyethylene having a thickness of 30 μm. 10,000 fine recesses 167 with a width of about 20 μm / cm ² The recesses were formed in large numbers and uniformly at a density of. In addition, the recess 16
The average thickness of the remaining thin film portion 171 of the long organic resin film 160 located at the bottom of No. 7 was about 10 μm.
Further, in the remaining thin film portion 171, crushed pieces of Otani stone particles crushed by the recess forming operation (average particle diameter 5 μm) 16
A large number of hair cracks 169 penetrating the remaining thin film portion 171 were formed around 8 and the high hardness zeolite particles 165 were dispersed in the organic resin film 160 in the same shape without being substantially crushed. . Example 2

Low density polyethylene (LDPE) and ethylene-vinyl acetate copolymer (EVA) were mixed in a weight ratio of 5: 5 to a mixed resin, Otani stone particles having an average particle diameter of 15 μm, and zeolite particles having an average particle diameter of 15 μm ( A blending weight ratio of 9: 1) was added in a total amount of 1.0% by weight, and after kneading and dispersing, a film was formed by an inflation method to obtain a thickness 30 in which zeolite particles and Otani stone particles were dispersed.
A long organic resin film having a thickness of μm was produced. This long organic resin film was treated in the same manner as in Example 1 to produce a long freshness-keeping film. Example 3

Linear low density polyethylene (LLDPE) and ethylene-vinyl acetate copolymer (EVA) were mixed with 7: 3.
0.15 wt% of Otaniishi particles having an average particle size of 15 μm and zeolite particles having an average particle size of 15 μm (blending weight ratio 2: 1) were added in a total amount of 0.15% by weight to the mixed resin mixed after kneading and dispersing. The film was formed by the inflation method to prepare a long organic resin film having a thickness of 25 μm in which the zeolite particles and Otaniishi particles were dispersed.
This long organic resin film was treated in the same manner as in Example 1 to produce a long freshness-keeping film. Comparative example

5.0% by weight of Otani stone particles having an average particle diameter of 15 μm was added to low density polyethylene (LDPE) and kneaded.
After dispersion, a film was formed by an inflation method to produce a long organic resin film (freshness-keeping film) having a thickness of 30 μm in which Otaniishi particles were dispersed.

The freshness-keeping films obtained in Examples 1 to 3 and Comparative Example were evaluated for oxygen permeability, moisture permeability and transparency. The results are shown in Table 1 below. In addition, regarding Examples 1 to 3, the oxygen transmission amount, the moisture permeability and the transparency of the film before the recess formation treatment (before processing) are also shown in Table 1 below.

[0052]

[Table 1]

As is clear from Table 1, Examples 1 to 3
It can be seen that the freshness-keeping film obtained by the above-mentioned method has remarkably increased oxygen permeation amount and moisture permeability as compared with the organic resin film in which unprocessed zeolite particles and Otaniishi particles are dispersed.

On the other hand, the freshness-keeping film, which is commercially available as a freshness-keeping film and is made of LDPE in which only Otaniishi particles are simply dispersed, has a relatively high moisture permeability,
It can be seen that since Otaniishi particles are included in a large amount of 5.0% by weight, the particles become cloudy and opaque.

A wrapping material was prepared from the freshness keeping path film of Example 1, and a bundle of spinach was placed in the wrapping material and the opening was closed. Also, a packaging material was prepared from a freshness-keeping film in which only Otaniishi particles of Comparative Example were simply dispersed, and a similar bundle of spinach was housed in the packaging material and the opening was closed. Each of the packaging materials in which the bundle of spinach was stored and sealed was left at room temperature for 1 week, and then the state of the spinach was observed. As a result, most of the spinach stored in the packaging material of the comparative example turned yellow and was in a state of on the verge of decay. On the other hand, the spinach stored in the packaging material made of the freshness keeping film of Example 1 had a fresh green color before being stored in the packaging material.

[0056]

As described above, according to the present invention, the permeation amount of oxygen gas, carbon dioxide gas and water vapor can be controlled without permeating bacteria and miscellaneous bacteria, and the gas such as water vapor and ethylene can be adsorbed. It is possible to provide a freshness-keeping film capable of holding the freshness of various fruits and vegetables for a long period of time.

Further, according to the present invention, it is possible to provide a method for producing a freshness-keeping film capable of producing the freshness-keeping film having the above-mentioned excellent characteristics with good reproducibility and in mass production.

[Brief description of drawings]

FIG. 1 is a front view showing an apparatus for producing a freshness-keeping film used in an example of the present invention.

FIG. 2 is a side view showing a main part of the manufacturing apparatus in FIG.

FIG. 3 is a sectional view taken along the line III-III in FIG.

FIG. 4 is a front view for explaining a recess forming operation on a long organic resin film by the manufacturing apparatus of FIG.

5 is an enlarged cross-sectional view of a main part of a first roll in the manufacturing apparatus of FIG.

FIG. 6 is a cross-sectional view showing a long organic resin film in which ceramic particles produced in Example 1 are dispersed.

7 is an enlarged sectional view of an essential part for explaining a step of forming a recess and a hair crack in a long organic resin film in which ceramic particles are dispersed by the manufacturing apparatus of FIG.

8 is an enlarged cross-sectional view showing a freshness keeping film manufactured by the recess forming operation of FIG.

[Explanation of symbols]

101 ... Bed, 106 ... First roll, 107 ... Synthetic diamond particles, 117 ... Second roll, 124 ... Third roll, 129 ... Recess forming unit, 144 ... First pressure adjusting means, 159 ... Second pressure adjusting means , 160 ... Long organic resin film, 162 ... Electrostatic removal means, 165 ... Zeolite particles, 166 ... Otani stone particles, 167 ... Recesses, 1
68 ... Crushed pieces, 169 ... Hair cracks, 170 ... Long freshness-keeping film, 171 ... Residual thin film portion.

Claims (4)

[Claims] 1. An organic resin film, a large number of two or more kinds of ceramic particles dispersed in the film having different hardness, a large number of concave portions having a fine opening width formed in the film, and a bottom portion of the concave portion. And a residual thin film portion formed in the film portion located at, ceramic particles having at least high hardness among the ceramic particles have high gas and water vapor adsorption and are dispersed in the residual thin film portion. A freshness-retaining film, wherein a large number of hair cracks penetrating the remaining thin film are formed around the ceramic particles having low hardness. 2. The freshness-keeping film according to claim 1, wherein the ceramic particles having different hardnesses are zeolite particles and Oyaishi stone particles. 3. The freshness-keeping film according to claim 1, wherein the thickness of the remaining thin film portion of the organic resin film located at the bottom of the recess is 15 μm or less. 4. A step of kneading and dispersing a large number of ceramic particles having different hardness in an organic resin and forming a film to form a long organic resin film in which the ceramic particles are dispersed; having a sharp corner portion. While the first roll having a large number of particles having a Mohs hardness of 5 or more adhered to the surface and the second roll having a smooth surface are rotated in opposite directions, the long organic resin is provided between the first and second rolls. While passing through the film, by applying a constant pressure to the film passing between the rolls so as to be uniform over the entire film surface in contact with the rolls, the sharpness of a large number of particles on the surface of the first roll is sharpened. The corners are bitten into the long organic film to form a large number of fine recesses, and at the same time, the hard particles dispersed in the film portion located between the sharp corners of the particles and the second roll. A method for producing a freshness-retaining film, comprising the step of crushing low-grade ceramic particles to form a large number of hair cracks around them.