Synthetic resin film for vegetables and fruits freshness keeping storage bag, and vegetables and fruits freshness keeping storage bag

Abstract

To provide a long synthetic resin film capable of efficiently manufacturing a freshness keeping storage bag with a good yield without generating a reading mistake of a phototube mark during bag-making processing and automatic packaging, and capable of forming the freshness keeping storage bag which exhibits an excellent freshness keeping effect.SOLUTION: A long OPP film F of a predetermined thickness is irradiated with CO2 laser under a predetermined condition at predetermined intervals to form S-shaped transparent stripes L, L ..., and then is wound in a roll shape. Further, in parallel with the irradiation of the laser and at the same intervals as it, rectangular phototube marks M, M ... are intermittently printed on one end edge of the OPP film F. Then, by using the OPP film F and heat-sealing at the predetermined intervals on the basis of detection of the phototube marks M, M ... by a photoelectronic sensor, vegetables and fruits freshness keeping storage bags for storing vegetables and fruits are continuously manufactured.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a freshness-maintaining storage bag for fruits and vegetables, and a long synthetic resin film (film roll) used to form the freshness-maintaining storage bag for fruits and vegetables. [Background technology]

[0002] Known storage bags for storing various types of produce, such as leafy vegetables, fruit vegetables, root vegetables, fruits, and fungi, while maintaining their freshness include two-sided bags, three-sided bags, pillow bags, pouches, and gusset bags made of synthetic resin film. Such synthetic resin film storage bags are often formed by a bag-making process in which two sheets of synthetic resin film are stacked (or a single synthetic resin film is folded) and the periphery is heat-sealed (thermally bonded). Therefore, storage bags made of polyolefin film are widely used because of their ease of heat sealing (the ability to heat-seal at relatively low temperatures). Furthermore, because polyolefin film storage bags have low water vapor permeability, bags with fine permeable holes or slits to adjust the water vapor permeability have been developed to achieve a good freshness-maintaining effect for produce (Patent Document 1).

[0003] Storage bags made of polyolefin film having fine holes or slits as described above are usually produced by unrolling a film roll made of a long, fixed-width polyolefin film, forming fine holes or slits in the film by irradiating it with a laser (laser beam) or pricking it with a needle, and then temporarily winding up the long film with the holes or slits into a roll before subjecting it to bag-making processing. When producing storage bags made of polyolefin film having such holes or slits, a widely used method is to print photocell marks at regular intervals on one edge of the polyolefin film when the holes or slits are formed, and then heat-seal (fuselage-cut) the photocell marks when detected by a sensor during bag-making processing in order to efficiently produce storage bags of the same shape.

[0004] Another method for storing fruits and vegetables in storage bags made of polyolefin film with holes and slits is to use a pillow packaging machine or the like to punch holes and slits into a long piece of film with photocell marks printed at predetermined intervals, fold the film in half lengthwise, and heat-seal the edges to form a long cylindrical body, and then fill the long cylindrical body with fruits and vegetables while heat-sealing the bag when the photocell marks are detected by a sensor, thereby storing the fruits and vegetables at the same time as the bag is made (so-called automatic packaging). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2004-284654 Summary of the Invention [Problem to be solved by the invention]

[0006] However, when manufacturing storage bags made of polyolefin film with the above-described perforations or slits, depending on how the perforations or slits are formed, the film on the outside or inside of the perforations or slits of the wound film roll may be deformed. This deformation may lead to misreading of the photocell mark during the bag manufacturing process. This may result in irregularly shaped storage bags or reduced yields due to improperly heat-sealed bags. Furthermore, when packaging fresh produce automatically, improperly heat-sealed bags may result in portions of the produce being trapped in the heat seal. Furthermore, depending on how the perforations or slits are formed, the freshness-preserving effect of the storage bags may be poor when stacked with fresh produce stored inside.

[0007] The object of the present invention is to solve the problems of the above-mentioned conventional synthetic resin films used to form freshness-preserving storage bags for fruits and vegetables, to enable the efficient production of freshness-preserving storage bags with high yield without causing errors in reading the photocell mark during bag manufacturing or automatic packaging, and to provide a long synthetic resin film (film roll) that can be used to form freshness-preserving storage bags that exhibit good freshness-preserving effects even when stacked and used with fruits and vegetables stored inside. [Means for solving the problem]

[0008] Of the present inventions, the invention described in claim 1 is a long synthetic resin film used to form freshness-preserving storage bags for fruits and vegetables, which is made of biaxially oriented polypropylene film, and which has a portion that penetrates from the front to the back by irradiating it with a laser, and which has a lumpy portion formed around the penetrated portion due to thermal shrinkage, and which is characterized in that the average value of the angle of the top and the angle of the bottom of the lumpy portion at each point obtained by dividing the lumpy portion around the penetrated portion into five equal parts in the longitudinal direction is 30° or more and less than 100°, and the width of the lumpy portion at each point obtained by dividing the lumpy portion around the penetrated portion into five equal parts in the longitudinal direction is 100 μm or more and less than 300 μm.

[0009] The invention described in claim 2 is characterized in that, in the invention described in claim 1, the penetrating portion is a long penetrating wire of a constant width that is bent in an S-shape.

[0010] The invention described in claim 3 is characterized in that, in the invention described in claim 1, the thickness of the biaxially oriented polypropylene film is 5 to 50 μm.

[0011] The invention described in claim 4 is characterized in that, in the invention described in claim 1, the long, S-shaped, constant-width through-line (hereinafter referred to as the S-shaped through-line) has a width of 0.05 to 2.0 mm, a length of 2.0 to 20.0 mm, and a height of 1.0 to 15.0 mm.

[0012] The invention described in claim 5 is a freshness-preserving storage bag for fruits and vegetables, characterized in that it is formed from the synthetic resin film described in any one of claims 1 to 3. [Effects of the Invention]

[0013] The synthetic resin film for forming freshness-maintaining storage bags for fruits and vegetables according to claim 1 (hereinafter simply referred to as the film for forming freshness-maintaining storage bags) makes it easy to manufacture freshness-maintaining storage bags for fruits and vegetables with a high freshness-maintaining effect. Furthermore, the film for forming freshness-maintaining storage bags according to claim 1 has a specific shape in the block portion around the perforated portion caused by laser irradiation, which reduces the amount of deformation of the film on the outside and inside of the perforated portion when rolled up. This allows for good processing yield without misreading the photocell mark during bag production, and effectively prevents the fruit and vegetables from getting caught in the bag due to misreading the photocell mark during automatic packaging.

[0014] The film for forming freshness-keeping storage bags according to claim 2 has S-shaped perforated wires as the perforated portions, so that fruit and vegetable freshness-keeping storage bags with an extremely high freshness-keeping effect can be easily manufactured.

[0015] The film for forming freshness-preserving storage bags according to claim 3 is formed from a biaxially oriented polypropylene film having a predetermined thickness, and therefore, when wound up, the amount of deformation of the film on the outside and inside of the perforated portion can be significantly reduced, making it possible to prevent errors in reading the photocell mark with greater accuracy during the bag-making process.

[0016] The film for forming freshness-keeping storage bags according to claim 4 has S-shaped through-lines adjusted to a predetermined size and shape, making it possible to easily manufacture freshness-keeping storage bags for fruits and vegetables that have an extremely high freshness-keeping effect.

[0017] The freshness-keeping storage bag for fruits and vegetables according to claim 5 has a perforated portion, which allows it to exhibit an extremely high freshness-keeping effect for fruits and vegetables, and since there are no errors in reading the photocell mark during manufacturing (i.e., when making bags from a long film (film roll)), it can be manufactured cheaply and easily with a good yield. Furthermore, the freshness-keeping storage bag for fruits and vegetables according to claim 5 can exhibit an extremely good freshness-keeping effect even when stacked with fruits and vegetables stored inside (hereinafter, the freshness-keeping properties when stacked with fruits and vegetables stored inside will be referred to as the freshness-keeping properties when stacked). [Brief explanation of the drawings]

[0018] [Figure 1] An explanatory diagram showing the formation area of ​​the perforated portion (S-shaped perforated line) of the film for forming a freshness-keeping storage bag (a is a plan view, b is a cross-sectional view along line AA in a, and c is an explanatory diagram showing an enlarged view of the α portion in b). [Figure 2] FIG. 1 is an explanatory diagram (plan view) showing how a freshness-keeping storage bag for fruits and vegetables is made using a film for forming a freshness-keeping storage bag. [Figure 3] FIG. 1 is an explanatory diagram (plan view) showing a freshness-keeping storage bag manufactured from a film for forming a freshness-keeping storage bag. DETAILED DESCRIPTION OF THE INVENTION

[0019] The film for forming freshness-keeping storage bags according to the present invention is made of biaxially oriented polypropylene film (OPP film), and by irradiating it with a laser, a perforated portion (a hollow portion that penetrates the front and back of the film, an S-shaped line in FIG. 1) L is formed, as shown in FIG. 1, and a block portion (i.e., a portion that melts, shrinks, and solidifies due to the heat generated by the laser irradiation) B is formed around the perforated portion L. As will be described later, by irradiating the laser under predetermined conditions, a block portion B is formed, as shown in FIG. 1, whose cross section (a vertical cross section perpendicular to the longitudinal direction of the perforated portion) is approximately rectangular (a rectangle with rounded vertices). The film for forming freshness-keeping storage bags according to the present invention has an angle θ at the top of the block portion B. t and the bottom angle θ b The average value of θ a is adjusted to fall within a predetermined range, and the width W of the block portion B is adjusted to fall within a predetermined range. By irradiating the OPP film with a laser in this way, a perforated portion is formed, and the shape of the block portion B around the perforated portion (the average value θ of the angles of the upper and lower vertices) is also adjusted. a and width W) to a specific shape, it is possible to reduce the occurrence of errors in reading the photocell mark during bag production or automatic packaging, and to improve the freshness-keeping properties of freshness-keeping storage bags containing fruits and vegetables when stacked.

[0020] The film for forming freshness-maintaining storage bags according to the present invention must be made of OPP film. The thickness of the OPP film is not particularly limited, but is preferably in the range of 5 to 90 μm, and more preferably in the range of 20 to 70 μm. OPP film thicknesses below 5 μm are undesirable because they lack the so-called "rigidity" of the film, making them prone to wrinkling when formed into freshness-maintaining storage bags and used to store fruit and vegetables. They also lack volume, making them difficult to handle. Conversely, OPP film thicknesses above 90 μm are undesirable because they become too rigid, making it difficult to seal the freshness-maintaining storage bags after they have been formed into freshness-maintaining storage bags and used to store fruit and vegetables. The stretching ratio of the OPP film is also not particularly limited, and any stretching ratio can be used. However, it is preferable to use OPP film stretched 2 to 5 times in both the longitudinal direction (MD) and the transverse direction (TD), as this ensures that the resulting freshness-maintaining storage bags have appropriate flexibility and rigidity.

[0021] The film for forming freshness-keeping storage bags according to the present invention must have perforations formed at predetermined intervals along the longitudinal direction by irradiating it with a laser. The shape of the perforations is not particularly limited, and may be simple circular or elliptical holes, or polygonal holes such as triangular or rectangular holes, or may be straight or curved perforated lines. Furthermore, it is preferable to form the perforations in the shape of S-shaped perforated lines (i.e., long perforated lines of a constant width bent in an S shape), as this improves the freshness-keeping properties of the freshness-keeping storage bag containing fruits and vegetables.

[0022] Furthermore, as described above, when the shape of the through portion is an S-shaped through-line, the shape of the S is not particularly limited, but it is preferably formed by a continuous curve without any acute angles, and more preferably a shape in which the tip of the upper portion is bent downward and the tip of the lower portion is bent upward. In addition, when the shape of the through portion is an S-shaped through-line, the size of the S-shaped through-line is set to be 0.05 to 2.0 mm in width, 2.0 to 20.0 mm in length, and 1.0 to 15.0 mm in height (i.e., the maximum length of the S in the vertical direction), which makes it easier to adjust the inclination angle of the outer surface of the block portion B formed around the S-shaped through-line to a predetermined angle when forming a freshness-preserving storage bag, making it possible to more effectively prevent errors in reading the photocell mark and to achieve very good freshness-preserving properties of the freshness-preserving storage bag, which is preferable.

[0023] Furthermore, in the film for forming freshness-maintaining storage bags according to the present invention, it is necessary to adjust the block portion B formed around the perforated portion formed in the OPP film by the laser irradiation as described above to a specific shape. That is, in the film for forming freshness-maintaining storage bags according to the present invention, the angle θ of the top of the block portion B around the perforated portion is adjusted. t and the bottom angle θ b The average value of θ a (That is, at each of the points P1 to P5 that divide the entire circumference of the block portion B into five equal parts in the longitudinal direction, the angle θ t and the bottom angle θ b The angle θ is the average value of b and measure their inclination angles θ a1 ~θ a5 The average angle of the uppermost part of the block B (see Fig. 1(c)) must be adjusted to 30° or more and less than 100° (the angle θ t and the bottom angle θ b (Examples of the measurement method will be described later.) The angle θ between the top and bottom vertices of the block part B t ,θ b The average value of θ aIf the angle θ of the upper and lower vertices of the block portion B is less than 30°, the deformation of the film on the outside and inside of the perforated portion will be large when the block portion B is wound into a roll, which is undesirable because it will easily cause errors in reading the photocell mark during bag making and automatic packaging. t ,θ b The average value of θ a If the angle θ between the top and bottom vertices of the block portion B is 100° or more, when multiple freshness-preserving storage bags (or automatically packaged freshness-preserving storage bags) containing fruit and vegetables after bag making are stacked, the freshness-preserving storage bag located at the bottom will not be able to exhibit good freshness-preserving properties due to a decrease in the amount of water vapor that can pass through, which is not preferable. t ,θ b The average value of θ a It is more preferable that the angle is 40° or more and less than 90°.

[0024] Furthermore, the film for forming freshness-maintaining storage bags according to the present invention must have a width W of the chunky portion B surrounding the perforated portion adjusted to 100 μm or more and less than 300 μm. If the width W of the chunky portion B is less than 110 μm, when multiple freshness-maintaining storage bags (or automatically packaged freshness-maintaining storage bags) containing fruit or vegetables are stacked after bag formation, the lowermost freshness-maintaining storage bag will not exhibit good freshness-maintaining properties due to a decrease in the amount of water vapor and other permeability, which is undesirable. Conversely, if the width W of the chunky portion B is 300 μm or more, when the film is wound into a roll, the amount of deformation of the film on both the outside and inside of the perforated portion will be significant, which is undesirable because it will increase the likelihood of misreading the photocell mark during bag formation or automatic packaging. It is more preferable that the width of the chunky portion B be 140 μm or more and less than 220 μm.

[0025] In addition, the film for forming a freshness-keeping storage bag according to the present invention has an inclination angle θ of the outer surface of the block portion B around the perforated portion (i.e., the inclination angle θ of the upper outer surface of the block portion B relative to the horizontal plane at each of points P1 to P5 that divide the entire circumference of the block portion B into five equal parts in the longitudinal direction). u and the inclination angle θ of the lower outer surface of the block part B with respect to the horizontal plane dIf the inclination angle θ (inclination angles θ1 to θ5), which is the average of the angles θ1 to θ5, is measured and the average of these inclination angles θ1 to θ5 is calculated (see Figure 1(c)), and the inclination angle θ is adjusted to be between 25° and 80°, this is preferable because it prevents errors in reading the photocell mark during bag manufacturing and more stably prevents a decrease in the freshness-keeping properties of the freshness-keeping storage bag for the fruit or vegetable located at the bottom when multiple bags are stacked. In other words, if the inclination angle of the outer surface of the block portion B is less than 25°, when multiple freshness-keeping storage bags (or automatically packaged freshness-keeping storage bags) containing fruit or vegetable after bag manufacturing are stacked, the freshness-keeping storage bag located at the bottom will not be able to exhibit good freshness-keeping properties due to a decrease in the amount of water vapor and the like that can pass through, which is undesirable. On the other hand, if the inclination angle of the outer surface of the block portion B is 80° or more, the amount of deformation of the film on the outside and inside of the perforation portion will increase when the film is wound into a roll, which is undesirable as it will make it easier for errors to occur in reading the photocell mark during bag making and automatic packaging.More preferably, the inclination angle θ of the outer surface of the block portion B is 30° or more and less than 75°.

[0026] Furthermore, in the film for forming freshness-maintaining storage bags according to the present invention, if the difference between the height H of the chunks B around the perforated portion and the thickness of the film (i.e., the actual height of the chunks B) is adjusted to 110 μm or more and less than 500 μm, this is preferable because it prevents errors in reading the photocell mark during bag manufacturing and more consistently prevents a decrease in the freshness-maintaining properties of the freshness-maintaining storage bag for the fruit or vegetable located at the bottom when multiple bags are stacked. If the actual height of the chunks B is less than 110 μm, when multiple freshness-maintaining storage bags (or automatically packaged freshness-maintaining storage bags) containing fruit or vegetable after bag manufacturing are stacked, the freshness-maintaining storage bag located at the bottom will not be able to exhibit good freshness-maintaining properties due to a decrease in the amount of water vapor and the like that can pass through, which is undesirable. On the other hand, if the actual height of the lump portion B is 500 μm or more, the amount of deformation of the film on the outside and inside of the perforation portion will be large when the film is wound into a roll, which is undesirable because it will make it easier for errors to occur in reading the photocell mark during bag making processing or automatic packaging. It is more preferable that the actual height of the lump portion B be 120 μm or more and less than 350 μm.

[0027] To form the penetrating portions and massive portions B having the specific shapes described above, it is effective to irradiate the OPP film with a laser in a specific manner. Specifically, semiconductor lasers, carbon dioxide lasers, excimer lasers, YAG lasers, fiber lasers, and the like can be suitably used as lasers for drilling the penetrating portions. However, using a carbon dioxide laser (CO2 laser) is preferred because it enables a high-output laser with a small device to be obtained with no deviation in the optical axis, thereby increasing the dimensional accuracy of the penetrating portions formed and making it easier to adjust the shape of the massive portions B around the penetrating portions. Furthermore, the output and wavelength when forming the penetrating portions and massive portions B using a CO2 laser are not particularly limited, but adjusting the output to within a range of 10 to 40 W and the wavelength to within a range of 8.0 to 12.0 μm is preferred because it enables the penetrating portions and massive portions B having the specific shapes described above to be formed efficiently in a short time.

[0028] Furthermore, in order to form the perforated portion and block portion B of a specific shape, which is a requirement of the present invention, it is preferable to use a laser marker that can change the focal length in the thickness direction of the OPP film (for example, a three-dimensional control laser marker that can control the focal position in three dimensions along the X, Y, and Z axes) and irradiate the laser by adjusting the focal point so that it is 0.1 to 1.5 mm away from the surface of the OPP film (i.e., when irradiating the laser from above, the focal point is 0.1 to 1.5 mm below the surface of the OPP film), and it is even more preferable to adjust the focal point to be 0.3 to 1.2 mm away from the surface of the OPP film.

[0029] Furthermore, when forming a penetration portion by irradiating an OPP film with a CO2 gas laser, the inclination angle of the outer surface of the massive portion B around the penetration portion and the actual height of the massive portion B can be easily adjusted by adjusting the distance between the laser irradiation device and the OPP film to 50 to 300 mm, adjusting the scan speed to 500 to 2,500 mm / sec, and adjusting the number of irradiations to 1 to 6.

[0030] On the other hand, freshness-keeping storage bags manufactured using the film for forming freshness-keeping storage bags can achieve a water vapor permeability of 5g / (m 2 ·day.atm) or more 3,000g / (m 2 It is preferable to adjust the water vapor permeability of the freshness preservation storage bag to less than 5g / (m 2 -day.atm) or less than 3,000g / (m 2 If the temperature is higher than 100°C (1000°F / day, atm), it is not preferable because the good freshness-keeping properties cannot be exhibited.

[0031] In addition, the shape of the freshness-maintaining storage bag produced using the film for forming freshness-maintaining storage bags is not particularly limited, and various shapes are possible, such as a three-sided bag formed by heat-sealing the left, right, and bottom edges, a two-sided bag formed by heat-sealing the left and right edges of an OPP film folded in half, or a pillow bag formed by folding the left and right edges of an OPP film and heat-sealing the back. Furthermore, the size of the freshness-maintaining storage bag is not particularly limited as long as it is suitable for containing fruits and vegetables, but a width of 100 to 1200 mm and a height of 150 to 900 mm are preferred, as they provide good handling and freshness-maintaining properties for fruits and vegetables. The film for forming freshness-maintaining storage bags according to the present invention can be formed into two-sided bags, three-sided bags, pillow bags, and other shapes (containing various fruits and vegetables) by automatic packaging, which simultaneously forms the bags and stores the fruits and vegetables. [Example]

[0032] The film for forming a freshness-maintaining storage bag according to the present invention and the freshness-maintaining storage bag using the same will be described in detail below with reference to examples and comparative examples, but the film for forming a freshness-maintaining storage bag and the freshness-maintaining storage bag according to the present invention are not limited to the embodiments of the examples and can be modified as needed without departing from the spirit of the present invention. The methods for evaluating the properties in the examples and comparative examples are as follows.

[0033] <Inclination angle, top and bottom angles, width and height of the block part of the penetration part> Using a digital microscope VHX-1000 manufactured by Keyence Corporation, quick depth stacking & 3D was used to obtain 3D images of the penetrations formed in the film for forming freshness-preserving storage bags obtained in the Examples and Comparative Examples. Using the "interface angle" in the "3D measurement mode" of the "3D shape measurement software" (model VHX-H3M) installed in the digital microscope VHX-1000, the "interface angle" of two specified points on the outer surface of the block portion B around the penetrations was measured (i.e., the mid-height position (approximately 1 / 2 height) of block portion B in a vertical plane perpendicular to the outer surface of block portion B, and the base end (approximately horizontal portion) of block portion B), and the difference in inclination angle between the surfaces was determined as the inclination angle (interface angle) θ. The inclination angle (interface angle) θ was measured based on the inclination angle θ of the upper outer surface of block portion B relative to the horizontal plane. u and the inclination angle θ of the lower outer surface of the block part B with respect to the horizontal plane d and their inclination angles θ u and the inclination angle θ d The average value of these angles was calculated and used as the inclination angle θ. The inclination angle θ was measured by measuring the inclination angles θ1 to θ5 at points P1 to P5 (see Figure 1(a)) that divide the block portion B into five equal parts in the longitudinal direction in the three-dimensional image, and calculating the average of these measurements. Furthermore, the angle θ at the top of the block portion B was calculated using a similar image processing method. t (That is, the inclined surface S of the upper inner side of the block portion B in the vertical plane perpendicular to the longitudinal direction of the block portion B at each of the points P1 to P5 t1 and the upper outer slope S t2 The angle θ t ), the bottom angle θ b (That is, the inclined surface S of the lower inner side of the block portion B in the vertical plane perpendicular to the longitudinal direction of the block portion B at each of the points P1 to P5 b1 and the lower outer slope S b2 The angle θ b ), width W, and height H were measured (see Figure 1(c)). The actual height of the aggregate B was calculated by subtracting the film thickness from the measured height H of the aggregate B.

[0034] <Effect of preserving the freshness of fruits and vegetables (single product)> The freshness-preserving storage bags (pillow bags containing 350 g of broccoli automatically packaged) obtained in the examples and comparative examples were stored in an environment of 10°C x 40% RH for 7 days, after which the condition of the stored broccoli was subjected to a sensory evaluation on a 4-point scale in terms of the occurrence of off-flavors and discoloration. ◎: No strange odor or discoloration is observed (no difference from before packaging) ○: Very slight odor and discoloration are observed △: Unpleasant odor and discoloration are clearly observed ×: Overall, there is a strange odor and significant discoloration, and the product has lost its commercial value.

[0035] <Freshness preservation effect when stacked> Five freshness-preserving storage bags (pillow bags automatically packed with 350g of broccoli) obtained in the Examples and Comparative Examples were stacked one on top of the other and stored in an environment of 10°C x 40% RH for 7 days. After that, the condition of the pillow bag placed on the bottom layer and the broccoli stored in the pillow bag placed above it were subjected to a sensory evaluation using the same criteria as in the "effectiveness of preserving the freshness of fruits and vegetables" described above (the evaluation was based on the average of the two pillow bags).

[0036] [Example 1] A long OPP film (Toyobo Co., Ltd., biaxially oriented anti-fog polypropylene film P5573) with a thickness of 25 μm and a width of 620 mm was intermittently irradiated with a CO laser at predetermined intervals (200 mm intervals) using a 3Axis CO laser marker ML-Z9600 / 9610 manufactured by Keyence Corporation under the following conditions: a line speed of 40 m / min, an unwinding tension of 50 N, and a winding tension of 30 N. The perforated portions (S-shaped perforated lines) were then formed by intermittently irradiating the film with the perforated portions using a 3Axis CO laser marker ML-Z9600 / 9610 manufactured by Keyence Corporation under the following conditions. The long OPP film with the perforated portions formed was then wound into a roll. In parallel with the laser irradiation, rectangular (3.0 mm long x 5.0 mm wide) photoelectric cell marks were intermittently printed on one edge of the OPP film at the same intervals (200 mm intervals) to obtain a film for forming a freshness-keeping storage bag of Example 1. <Laser irradiation conditions> Output: 95 watts Scan speed: 1,450 mm / sec Number of times of printing (irradiation): 5 times (printing the same line 5 times) Depth direction (Z coordinate) focal length: 0.5 mm (focus point set approximately 0.5 mm below the film surface) Longitudinal (X-coordinate) focal length: 50mm Focal length in width direction (Y coordinate): -2.14mm

[0037] The resulting freshness-preserving storage bag-forming film (OPP film with perforations and a printed photocell mark) was then used to automatically package broccoli using a KSR Corporation reverse pillow packaging machine at a heat-sealing temperature of 160°C and a processing rate of 15 bags per minute, continuously producing 100 pillow bags (freshness-preserving storage bags for produce) containing 350g of broccoli. During automatic packaging, heat sealing was performed across the OPP film based on the detection of the photocell mark by a photoelectric sensor, but no errors were detected in the reading of the photocell mark. Figure 3 shows the resulting pillow bag (without broccoli inside). Pillow bag P measures 280mm high and 230mm wide, with the top and bottom edges heat-sealed and the center of the back surface (center in the width direction) heat-sealed vertically. Then, a predetermined length (10 mm) to the right of the center of the surface and a predetermined length (15 mm) above the bottom end, a perforated portion (S-shaped perforated line) L of a predetermined size (length = approximately 10.0 mm, height = 5.0 mm) that penetrates in an S-shaped, band-like shape with a constant width (0.4 mm) is formed with its longitudinal direction inclined at 63° relative to the width direction of the pillow bag P.

[0038] Furthermore, using the obtained film for forming freshness-keeping storage bags (OPP film with perforations and printed photocell marks), 100 pillow bags (freshness-keeping storage bags for fruits and vegetables) each measuring 165 mm wide x 210 mm high and containing 200 g of edamame were continuously produced by automatically packaging edamame at a heat-sealing temperature of 160°C and a rate of 30 bags / min using a vertical pillow packaging machine manufactured by Kawashima Seisakusho Co., Ltd. During automatic packaging, heat sealing was performed across the OPP film based on the detection of the photocell mark by a photoelectric sensor, and no errors were made in reading the photocell mark.

[0039] The obtained pillow bags were then used to evaluate the freshness-keeping properties of fruits and vegetables (broccoli) using the method described above. The evaluation results of the film for forming freshness-keeping storage bags and pillow bags of Example 1 are shown in Tables 1 and 2, along with the processing conditions and properties of the film for forming freshness-keeping storage bags.

[0040] [Example 2] The film for forming freshness-preserving storage bags of Example 2 was obtained by forming a perforated portion in the OPP film and printing a photocell mark on it and then rolling it up in the same manner as in Example 1, except that the laser irradiation conditions when forming the perforated portion were changed as follows. <Laser irradiation conditions> Output: 95 watts Scan speed: 1,450 mm / sec Printing (irradiation) count: 2 times (printing the same line twice) Depth (Z coordinate) focal length: 2.3 mm (focus point approximately 2.3 mm below the film surface) Longitudinal (X-coordinate) focal length: 50mm Focal length in width direction (Y coordinate): -2.14mm

[0041] Thereafter, 100 pillow bags containing 350 g of broccoli were continuously produced using the obtained film for forming freshness-maintaining storage bags by automatically packaging broccoli in the same manner as in Example 1. No errors in reading the photocell mark occurred during the automatic packaging. Furthermore, 100 pillow bags containing 200 g of edamame were continuously produced using the obtained film for forming freshness-maintaining storage bags by automatically packaging edamame in the same manner as in Example 1. No errors in reading the photocell mark occurred during the automatic packaging. The obtained pillow bags were then used to evaluate the freshness-maintaining properties of fruit and vegetables (broccoli) using the method described above. The evaluation results of the film for forming freshness-maintaining storage bags and pillow bags of Example 2 are shown in Tables 1 and 2, along with the processing conditions and properties of the film for forming freshness-maintaining storage bags.

[0042] [Example 3] The same procedure as in Example 1 was followed, except that the laser irradiation conditions for forming the perforated portion were changed as follows: a perforated portion was formed in the OPP film, a photocell mark was printed, and the film was rolled up to obtain the film for forming freshness-preserving storage bags of Example 3. <Laser irradiation conditions> Output: 78 watts Scan speed: 1,450 mm / sec Number of times of printing (irradiation): 6 times (printing the same line 6 times) Depth direction (Z coordinate) focal length: 0.5 mm (focus point set approximately 0.5 mm below the film surface) Longitudinal (X-coordinate) focal length: 50mm Focal length in width direction (Y coordinate): -2.14mm

[0043] The resulting film for forming freshness-maintaining storage bags was then used to automatically package broccoli in the same manner as in Example 1, continuously producing 100 pillow bags containing 350 g of broccoli. During the automatic packaging process, no errors occurred in reading the photocell mark. The resulting film for forming freshness-maintaining storage bags was also used to automatically package edamame soybeans in the same manner as in Example 1, continuously producing 100 pillow bags containing 200 g of edamame soybeans. During the automatic packaging process, no errors occurred in reading the photocell mark. The resulting pillow bags were then used to evaluate the freshness-maintaining properties of fruit and vegetables (broccoli) using the method described above. The evaluation results of the film for forming freshness-maintaining storage bags and pillow bags of Example 3 are shown in Tables 1 and 2, along with the processing conditions and properties of the film for forming freshness-maintaining storage bags.

[0044] [Example 4] The laser irradiation conditions for forming the perforated portion were changed as follows, and the shape of the perforated portion was changed to a circle with a diameter of 3.0 mm. Except for this, the same procedure as in Example 1 was used to form a perforated portion in the OPP film, print a phototube mark, and roll up the film, thereby obtaining the film for forming freshness-keeping storage bags of Example 4. <Laser irradiation conditions> Output: 78 watts Scan speed: 1,450 mm / sec Number of times of printing (irradiation): 6 times (printing the same line 6 times) Depth direction (Z coordinate) focal length: 0.5 mm (focus point set approximately 0.5 mm below the film surface) Longitudinal (X-coordinate) focal length: 50mm Focal length in width direction (Y coordinate): -2.14mm

[0045] The resulting film for forming freshness-maintaining storage bags was then used to automatically package broccoli in the same manner as in Example 1, continuously producing 100 pillow bags containing 350 g of broccoli. During the automatic packaging process, no errors occurred in reading the photocell mark. The resulting film for forming freshness-maintaining storage bags was also used to automatically package edamame soybeans in the same manner as in Example 1, continuously producing 100 pillow bags containing 200 g of edamame soybeans. During the automatic packaging process, no errors occurred in reading the photocell mark. The resulting pillow bags were then used to evaluate the freshness-maintaining properties of fruit and vegetables (broccoli) using the method described above. The evaluation results of the film for forming freshness-maintaining storage bags and pillow bags of Example 4 are shown in Tables 1 and 2, along with the processing conditions and properties of the film for forming freshness-maintaining storage bags.

[0046] [Comparative Example 1] The same procedure as in Example 1 was carried out except that the laser irradiation conditions for forming the perforated portion were changed as follows. A perforated portion was formed in the OPP film, a photocell mark was printed, and the film was then rolled up to obtain a film for forming freshness-preserving storage bags in Comparative Example 1. <Laser irradiation conditions> Power: 98 watts Scan speed: 1,450 mm / sec Printing (irradiation) count: 1 time Depth direction (Z coordinate) focal length: 0 mm (focus on the surface of the film) Longitudinal (X-coordinate) focal length: 50mm Focal length in width direction (Y coordinate): -2.14mm

[0047] The resulting film for forming freshness-maintaining storage bags was then used to automatically package broccoli in the same manner as in Example 1, continuously producing 100 pillow bags containing 350 g of broccoli. During the automatic packaging process, no errors occurred in reading the photocell mark. The resulting film for forming freshness-maintaining storage bags was also used to automatically package edamame soybeans in the same manner as in Example 1, continuously producing 100 pillow bags containing 200 g of edamame soybeans. During the automatic packaging process, no errors occurred in reading the photocell mark. The resulting pillow bags were then used to evaluate the freshness-maintaining properties of fruit and vegetables (broccoli) using the method described above. The evaluation results of the film for forming freshness-maintaining storage bags and pillow bags of Comparative Example 1 are shown in Tables 1 and 2, along with the processing conditions and properties of the film for forming freshness-maintaining storage bags.

[0048] Comparative Example 2 The same procedure as in Example 1 was carried out except that the laser irradiation conditions for forming the perforated portion were changed as follows. A perforated portion was formed in the OPP film, a photocell mark was printed, and the film was then rolled up to obtain a film for forming freshness-preserving storage bags in Comparative Example 1. <Laser irradiation conditions> Output: 95 watts Scan speed: 1,450 mm / sec Printing (irradiation) count: 1 time Depth direction (Z coordinate) focal length: 0.3 mm (focus point set approximately 0.3 mm below the film surface) Longitudinal (X-coordinate) focal length: 50mm Focal length in width direction (Y coordinate): -2.14mm

[0049] Subsequently, the resulting film for forming freshness-maintaining storage bags was used to automatically package broccoli in the same manner as in Example 1, continuously producing 100 pillow bags containing 350 g of broccoli. However, there were many errors in reading the photocell mark (yield = approximately 70%). Furthermore, the resulting film for forming freshness-maintaining storage bags was used to automatically package edamame soybeans in the same manner as in Example 1, continuously producing 100 pillow bags containing 200 g of edamame. No errors in reading the photocell mark occurred during automatic packaging. The resulting pillow bags were then used to evaluate the freshness-maintaining properties of fruits and vegetables (broccoli) using the method described above. The evaluation results of the film for forming freshness-maintaining storage bags and pillow bags of Comparative Example 3 are shown in Tables 1 and 2, along with the processing conditions and properties of the film for forming freshness-maintaining storage bags.

[0050] Comparative Example 3 The same procedure as in Example 1 was carried out except that the laser irradiation conditions for forming the perforated portion were changed as follows. A perforated portion was formed in the OPP film, a photocell mark was printed, and the film was then rolled up to obtain a film for forming freshness-preserving storage bags in Comparative Example 1. <Laser irradiation conditions> Output: 95 watts Scan speed: 1,450 mm / sec Number of times of printing (irradiation): 8 times (printing the same line 8 times) Depth direction (Z coordinate) focal length: 2.5 mm (focus point set approximately 2.5 mm below the film surface) Longitudinal (X-coordinate) focal length: 50mm Focal length in width direction (Y coordinate): -2.14mm

[0051] The resulting film for forming freshness-maintaining storage bags was then used to automatically package broccoli in the same manner as in Example 1, resulting in the continuous production of 100 pillow bags containing 350g of broccoli. However, there were frequent errors in reading the photocell mark (yield: approximately 70%). Furthermore, the resulting film for forming freshness-maintaining storage bags was used to automatically package edamame soybeans in the same manner as in Example 1, resulting in the continuous production of 100 pillow bags containing 200g of edamame. There were frequent instances of the edamame getting stuck in the pouch due to errors in reading the photocell mark (incidence rate: approximately 10%). The resulting pillow bags were then used to evaluate the freshness-maintaining properties of fruit and vegetables (broccoli) using the method described above. The evaluation results of the film for forming freshness-maintaining storage bags and pillow bags of Comparative Example 3, along with the processing conditions and properties of the film for forming freshness-maintaining storage bags, are shown in Tables 1 and 2.

[0052] Comparative Example 4 The same procedure as in Example 1 was carried out except that the laser irradiation conditions for forming the perforated portion were changed as follows. A perforated portion was formed in the OPP film, a photocell mark was printed, and the film was then rolled up to obtain a film for forming freshness-preserving storage bags in Comparative Example 1. <Laser irradiation conditions> Output: 95 watts Scan speed: 1,450 mm / sec Number of times of printing (irradiation): 8 times (printing the same line 8 times) Focal length in the depth direction (Z coordinate): 2.0 mm (focus point set approximately 2.0 mm below the film surface) Longitudinal (X-coordinate) focal length: 50mm Focal length in width direction (Y coordinate): -2.14mm

[0053] Subsequently, the resulting film for forming freshness-maintaining storage bags was used to automatically package broccoli in the same manner as in Example 1, resulting in the continuous production of 100 pillow bags containing 350 g of broccoli. However, there were frequent errors in reading the photocell mark (yield: approximately 70%). Furthermore, the resulting film for forming freshness-maintaining storage bags was used to automatically package edamame soybeans in the same manner as in Example 1, resulting in the continuous production of 100 pillow bags containing 200 g of edamame. There were frequent instances of the edamame getting stuck in the pouch due to errors in reading the photocell mark (incidence rate: approximately 25%). The resulting pillow bags were then used to evaluate the freshness-maintaining properties of fruit and vegetables (broccoli) using the method described above. The evaluation results of the film for forming freshness-maintaining storage bags and pillow bags of Comparative Example 4, along with the processing conditions and properties of the film for forming freshness-maintaining storage bags, are shown in Tables 1 and 2.

[0054] [Table 1]

[0055] [Table 2]

[0056] From Tables 1 and 2, the angle θ of the upper and lower vertices of the block part B around the penetration part t ,θ b The average value of θ a It can be seen that all freshness-maintaining storage bags (automatically packaged for fruits and vegetables) formed using a film for forming freshness-maintaining storage bags in which the width W of the block portion B satisfies the requirements of the present invention are good in both the effect of preserving the freshness of the fruits and vegetables and the effect of preserving the freshness when stacked (Examples 1 to 4).It can also be seen that when freshness-maintaining storage bags are manufactured using a film for forming freshness-maintaining storage bags that satisfies the requirements of the present invention, there were no errors in reading the photocell mark (Examples 1 to 4).

[0057] On the other hand, the angle θ of the upper and lower vertices of the block part B around the penetration part t ,θ b The average value of θ aHowever, it was found that a freshness-preserving storage bag (automatically packaged for fruits and vegetables) formed using a small film for forming freshness-preserving storage bags that did not meet the requirements of the present invention was prone to misreading of the photocell mark and had poor freshness-preserving effect when stacked (Comparative Example 4). t ,θ b The average value of θ a It can be seen that when a freshness-preserving storage bag is manufactured using a film for forming a freshness-preserving storage bag in which the width W of the block portion B around the S-shaped through-line is large and does not meet the requirements of the present invention, the freshness-preserving effect during lamination is poor (Comparative Examples 1 and 2). On the other hand, when a freshness-preserving storage bag is manufactured using a film for forming a freshness-preserving storage bag in which the width W of the block portion B around the S-shaped through-line is large and does not meet the requirements of the present invention, it can be seen that not only are misreading of the photocell markings likely to occur, but also that the freshness-preserving effect during lamination is poor (Comparative Example 3). [Industrial Applicability]

[0058] Because the film for forming freshness-maintaining storage bags according to the present invention has the excellent effects described above, it can be suitably used as a synthetic resin film for manufacturing freshness-maintaining storage bags for various fruits and vegetables, or for forming freshness-maintaining storage bags that contain various fruits and vegetables by automatic packaging.Furthermore, because the freshness-maintaining storage bag according to the present invention has the excellent effects described above, it can be suitably used as a package for maintaining the freshness of various fruits and vegetables. [Explanation of symbols]

[0059] F··Freshness-preserving storage bag forming film P··Freshness-preserving storage bag L··S-shaped through-holes (through-holes) M··Phototube mark B...Lumpy part θ u The angle of inclination of the upper outer surface of the block θ d The angle of inclination of the upper outer surface of the block θ t ··Angle of top of block θb ··Angle of the bottom of the block W: Width of the block H: Height of the block

Claims

1. A long synthetic resin film used to form freshness-preserving storage bags for fruits and vegetables, It is made of biaxially oriented polypropylene film, A portion that penetrates from the front to the back is formed by irradiating the laser, and a lump portion is formed around the penetration portion due to thermal contraction, The average value of the angle of the top and bottom of the massive portion at each of five equal points obtained by dividing the massive portion around the penetrating portion into five equal parts in the longitudinal direction is 30° or more and less than 100°, and A synthetic resin film for forming freshness-preserving storage bags for fruits and vegetables, characterized in that the width of the lumpy portion around the perforated portion at each of five equal points in the longitudinal direction is 100 μm or more and less than 300 μm.

2. 2. The synthetic resin film for forming a freshness-preserving storage bag for fruits and vegetables according to claim 1, wherein the through-holes are long, S-shaped through-holes of a constant width.

3. 2. The synthetic resin film for forming a freshness-preserving storage bag for fruits and vegetables according to claim 1, wherein the thickness of the biaxially oriented polypropylene film is 5 to 50 μm.

4. The synthetic resin film for forming freshness-preserving storage bags for fruits and vegetables according to claim 1, characterized in that the long, S-shaped, constant-width through-stripe has a width of 0.05 to 2.0 mm, a length of 2.0 to 20.0 mm, and a height of 1.0 to 15.0 mm.

5. A freshness-preserving storage bag for fruits and vegetables, formed from the synthetic resin film according to any one of claims 1 to 4.

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