JPS593338B2 - Fruit and vegetable bags and their manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fruit and vegetable bag and a method for manufacturing the same, and more particularly to a fruit and vegetable bag made of biaxially oriented polystyrene film that maintains good freshness and can be sealed, and a method for continuously manufacturing the same.

Fruits and vegetables continue to function as living organisms even after they are harvested from the field.

After harvesting, they cannot receive nutritional support, so they continue to perform respiration activities while depleting their own body components. The magnitude of this respiration effect differs significantly depending on the type of fruits and vegetables, as shown in Tables 1 and 2, and it is said that the more intense the respiration effect is, the faster the quality declines and the shorter the shelf life. 25 Table 1 Respiration rate of various vegetables (1952, Ogata) In addition, fruits and vegetables generally have a high moisture content (75-95%).
Wilting occurs due to moisture evaporation, reducing commercial value.

In general, the water transpiration rate of fruits and vegetables is high for leafy vegetables, and slow for stem vegetables, fruit vegetables, and root vegetables, in that order. Furthermore, as shown in Table 3, transpiration has a close relationship with the epidermal structure.

Next, when fruits and vegetables with a large respiration rate are sealed and packaged in a bag made of biaxially stretched polystyrene film, the 02 in the bag is consumed and reduced by the respiration of the fruits and vegetables, while the CO2 produced by oxidation accumulates. The process progresses as shown in FIG. 1 and reaches a steady state.

That is, the concentration of 02 in the bag rapidly decreases, and then settles at a constant concentration that is limited by the amount of 02 that permeates into the bag from the outside through the film. Furthermore, although the CO2 concentration rises rapidly, it diffuses into the outside world through the film, and as the CO2 concentration decreases, the respiratory action also gradually decreases, so as shown in the figure, the CO2 concentration gradually decreases after reaching the maximum value. When the CO2 concentration of fruits and vegetables is too high or the 02 concentration is too low, gas problems occur and the freshness of fruits and vegetables decreases. That is, as shown in Table 4, there is a limit value for the 02 concentration depending on the type, and below this concentration, normal respiratory action becomes impossible. In order to converge the 02 and CO2 concentration in the bag to values suitable for various fruits and vegetables, it is necessary to use a film that has a permeability of 02 and CO2 that is compatible with the respiration of the fruits and vegetables sealed in the bag. There is.

As shown in Table 5, biaxially oriented polystyrene film has a relatively high gas permeability, so when the above-mentioned fruits and vegetables that breathe heavily are sealed and packaged, the amount of CO in the bag is reduced. , 0, the concentration is automatically controlled to an appropriate value and an excellent freshness preservation effect can be exhibited. As shown in Tables 1 and 2, fruits and vegetables that have a relatively large respiration rate and, as shown in Table 3, have a high transpiration rate and therefore a large loss of freshness, are placed in biaxially stretched polystyrene film bags. If the bag is sealed and packaged inside the body, the CO2, 02 concentration and the amount of transpiration within the bag can be automatically and appropriately adjusted to maintain freshness.

In addition, as shown in Table 5, biaxially oriented polystyrene film has a higher moisture permeability than other films, so when packaging fruits and vegetables that undergo rapid transpiration, the water vapor inside the bag will radiate out of the bag. Although there is some weight loss, the fruit and vegetables do not get steamy and have an excellent effect of keeping fruits and vegetables fresh. The present invention has been made based on the above findings, and its gist is that
0-75μ biaxially stretched polystyrene film [thickness 25
Moisture permeability at μ is 100V/24hrs/DatlO
O'F' 90%R. H. (ASTME96MethO
dEL) or slightly higher, gas permeability Cc/
Mil/77! ″/24hrs/1aTm/73'
FO%R. H. (ASTM Dl434) is 02 gas 26
00~7700, CO2 gas 10000~26000
A rectangular bag body consisting of a polystyrene film, wherein the three periphery edges of the bag body are adhered by a hot-melt adhesive layer, and the inner surface of the opening of the other periphery is bonded to a temperature lower than the heat shrinkage start temperature of the biaxially stretched polystyrene film. A sealable bag for fresh fruits and vegetables coated with a hot-melt adhesive that can be thermally bonded at low temperatures and does not block at room temperature, and a bag made of the above-mentioned biaxially stretched polystyrene film with a thickness of 10 to 75 μm. A hot-melt adhesive that can be thermally bonded at a temperature lower than the thermal shrinkage start temperature of the film and does not block at room temperature is applied in a direction perpendicular to the running direction of the film at a position corresponding to the opening to be formed, and then cooled. Then, after applying hot melt adhesive in a U-shape to the positions where the other three peripheries of the bag are to be formed, the same films as above are stacked and pressed together, and the formed bag is cut to make a sealable rectangular fruit or vegetable product. This is a continuous method for manufacturing bags.

The present invention will be explained in detail below with reference to the drawings.

As shown in Figs. 2 to 4, two biaxially oriented polystyrene films 1 and 1, each having a thickness of 10 to 75 μm are glued together in a □ shape with a hot melt adhesive to form a bag with an opening 4 on one side. That is.

The adhesive parts are 2-1, 2-2, 2-3 in Figures 2 to 4.
Indicated by The thickness of this adhesive layer is about 10 to 60μ, and the width is 3
~6m7! It is about L. The adhesive strength of the bonded portion using the hot melt adhesive is about 800 to 2500 f/15 at room temperature.

Further, the inner surface of the film in the opening 4 is coated with a low-temperature hot-melt adhesive that can be thermally bonded at a temperature lower than the thermal contraction start temperature of the polystyrene film (the coated layer is indicated by 3).
)do. This low-temperature hot-melt part is sealed by heat-bonding after fruits and vegetables are inserted into the bag (FIG. 4). The adhesive strength of this opening is about 500 to 1500 f/151 m. Heating is done within the temperature range at which the stretched polystyrene film does not shrink due to heat (practically about 95 to 105 degrees Celsius)
It will be held in Furthermore, the low-temperature hot melt layer 3 must not cause blocking with the stretched polystyrene film v, thereby impairing the opening property. The thickness of the biaxially oriented polystyrene film is 10-75μ.

If it is less than 10μ, the strength of the film will be insufficient, and if it exceeds 75μ, storage stability will be poor.

Hot melt adhesives used in the present invention include, for example, Hamatite M-470 and M-410 manufactured by Yokohama Rubber Co., Ltd., and 2812 manufactured by Hirodine Industries, Ltd., which have a temperature lower than the thermal shrinkage start temperature of biaxially stretched polystyrene film. Examples of hot melt adhesives that can be thermally bonded and do not block at room temperature include 4600 and 4 manufactured by Hirodyne Industries Co., Ltd.
Some of them, such as 610, are solid at room temperature and become liquid when heated. In addition, there are adhesive hot melts, reactive hot melts, and the like as hot melt adhesives. Furthermore, an emulsion latex type in which the above-mentioned hot melt is suspended in water, a solvent type in which the hot melt is dissolved in a solvent, etc. can also be used. However, in that case, a step to remove the solvent and moisture is required. Further, the stretching ratio of the biaxially stretched polystyrene film is 2 to 40. Biaxially oriented polystyrene films also include films made of synthetic resins selected from the group consisting of polystyrene, polystyrene copolymers, and mixtures of polystyrene and polystyrene copolymers.

Fresh shiitake mushroom packaging will be described as an example and comparative example showing the excellent freshness preservation effect of sealed packaging using the above-mentioned stretched polystyrene film. Table 6 shows 18 raw shiitake mushrooms.
It shows the results of a storage test at ~22°C and humidity of 62-78% RH. Stretched polystyrene film (Stylo Film 8 manufactured by Asahi Tau Co., Ltd.) with a thickness of 30 μm (1 section x 80 μm (2 sections)), commercially available PP film (3 sections), and high-density PE film (4 sections) sealed in a bag. and commercially available P
We compared the shelf life with E-net bag packaging (5th section). In area 1, the weight loss rate was 4.2% on the 4th day, and the marketability was 3.2, indicating that the product value was sufficiently maintained.

In Wards 3 and 4, the weight loss rate was very low at 0.9 to 1.3% on the 4th day, but a strange odor developed on the 3rd day and the product lost its marketability.

Because the gas permeability of PP film and high-density PE film is low, the CO2 concentration inside the bag becomes excessive.
It is presumed that this is because the concentration was below the limit value and a state of anaerobic respiration occurred, and because PP film and high-density PE film have low water vapor permeability, the inside of the bag became humid and the raw shiitake mushrooms became stuffy. The PE net stuffing in District 5 had a remarkable weight loss rate, reaching 54.1% on the 4th day, and browning and white mold occurred, reaching marketability level 2 on the 3rd day, and it had no commercial value at all.

In this test, when the thickness of the biaxially stretched polystyrene film was less than 10 μm, the bag broke due to insufficient strength of the film.

In addition, when the thickness exceeds 75 μm, a strange odor occurs as in Sections 3 and 4, and the preservation advantage is lost. In the present invention, bags are made by adhesion using a hot melt adhesive (
b) A bag body with relatively high adhesive strength can be obtained (mouth)
This is because the bag-making process can be performed at a relatively high speed, so the bag-making process cost can be reduced, and two characteristics can be exhibited.

In addition, when a biaxially stretched polystyrene film is bonded by heat sealing, the bonding strength is as low as about 200y/15mm, and the edges (adhesive end surfaces) tend to break, making it impractical for practical use. An embodiment of a preferred continuous bag making method for biaxially oriented polystyrene film according to the present invention is shown in FIG. In FIG. 5, the upper raw material 5 of the biaxially stretched polystyrene film is
The film 6 fed out passes through a low-temperature hot melt applicator 7 and passes through a second film 6 in a direction perpendicular to the running direction of the film 6.
A low temperature hot melt coating layer 3 as shown in the figure is applied. In the coating machine 7, 7-1 is a hot melt bath, 7-2 is a heating heater equipped with a temperature controller, 7-3 is a low-temperature hot melt, 7-4 is a scraping roll, 7-5 is a doctor knife, 7-1 6 is mesh roll, 7-7 is letterpress roll,
7 and 8 are presser rolls. The temperature of each roll is adjusted appropriately depending on the performance of the low-temperature hot melt. The film 61 coated with the low-temperature hot melt is appropriately cooled by cold air from the air cooler 8. 9, a printing machine performs necessary printing on the film 6-1 that has passed the low-temperature hot melt coating process.

10 is a printing ink dryer, and 11 is a hot melt coating machine.

The coating machine 11 is similar to the low temperature hot melt coating machine 7 in the bath 1.
1-1, heater 11-2, hot melt 11-3, scraping roll 11-4, doctor knife 11-5, mesh roll 11-6, letterpress roll 11-7, presser roll 11-8, and has undergone a printing process. Hot melt is applied to the film 6-2 in a U-shape. The film 6-3 coated with hot melt is immediately transferred to the pressure roll 12-1,
At step 12-2, the film is overlapped and pressed with the biaxially stretched polystyrene film 13 supplied from the lower raw film 14 to form a bag as shown in FIGS. 2-4. The film 13 is fed from the lower original film 14 through a heating roll 15 . Letterpress roll J of low-temperature hot melt coating machine 7, gravure roll 9-1 of printing machine 9, letterpress roll 11- of hot melt coating machine 11
7 rotates mechanically or electrically in conjunction with each other, and printing or hot melt coating is performed at a predetermined position. Reference numeral 16 denotes a slitter which cuts the film in the machine direction in the case of a multiple type.

Reference numeral 17 uses a rotary cutter to cut each bag at right angles to the film flow direction to obtain a sealable rectangular bag.

18 is an integrating device.

This example shows a 150 x 170 m biaxially stretched polystyrene film used in the raw shiitake mushroom preservation test shown in Table 6.
It was possible to make 50,000 bags per hour at a rate of 60,000 bags per hour (4-unit system), and it was able to exhibit an excellent effect in reducing bag-making processing costs.

[Brief explanation of drawings]

Fig. 1 is a diagram showing the relationship between CO2 gas concentration and time when fruits and vegetables with a large respiration rate are sealed and packaged in a stretched polystyrene film bag, and Fig. 2 is a plan view showing an example of the bag body of the present invention. , FIG. 3 is a sectional view of FIG. 2, FIG. 4 is a sectional view showing the state after sealing, and FIG. 5 is a schematic diagram showing an embodiment of the continuous manufacturing method for bags of the present invention. 1, V, 6, 13...Stretched polystyrene film, 2...Hot melt adhesive layer, 3...
・Hot melt adhesive coating layer, 4...Opening, 6, 13...Film, 7, 11...
・Hot melt adhesive applicator, 16...Sliver 1 17...Rotary cutter 1.

Claims (1)

[Claims] 1 Biaxially stretched polystyrene film with a thickness of 10 to 75μ [moisture permeability at 25μ thickness is 100g/24hrs/m^
2at100°F90%R. H. (ASTME96Me
thodEL) or slightly higher, gas permeability c
c/mil/m^2/24/hrs/atm/73°F
0%R. H. (ASTMD1434) is O_2 gas 26
00~7700, CO_2 gas 10000~26000
is a rectangular bag body consisting of ], the three periphery edges of the bag body are adhered by a hot melt adhesive layer, and
The other one of the sealable fruit and vegetable bags is coated on the inner surface of the peripheral opening with a hot-melt adhesive that can be thermally bonded at a temperature lower than the thermal contraction start temperature of the stretched polystyrene film and does not block at room temperature. 2 Biaxially stretched polystyrene film with a thickness of 10 to 75μ [moisture permeability at 25μ thick is 100g/24hrs/m^
2at100°F90%R. H. (ASTME96Me
thodEL) or slightly higher, gas permeability c
c/mil/m^2/24hrs/1atm/73°F
0%R. H. (ASTMD1434) is O_2 gas 60
0 to 7,700, and CO_2 gas 10,000 to 26,000] at a position corresponding to the opening where the upper bag is to be formed.
A hot-melt adhesive that can be thermally bonded at a temperature lower than the thermal contraction start temperature of the film and does not block at room temperature is applied in a direction perpendicular to the running direction of the film and cooled, and then the other three peripheral edges of the bag are formed. A sealable rectangular fruit or vegetable bag characterized by applying a hot melt adhesive in a U-shape to the desired position, then overlapping and pressing the same film as above, and cutting the formed bag. continuous manufacturing method.