JP6212431B2 - Perforated film - Google Patents

Description

  The present invention relates to a perforated film.

  There is a so-called perforated film in which holes are made in a sheet, a film, a metal foil or the like manufactured from a synthetic resin. This perforated film is used in various applications. For example, there are uses such as freshness preservation of vegetables and fruits, back sheets such as diapers and sanitary products, oxygen absorbers and hygroscopic agents. Depending on each application, the gas permeation amount of air, oxygen, hydrogen, water vapor or the like is controlled by the shape, size and number of holes provided in the perforated film.

  As a method of obtaining such a perforated film, there is a method of perforating an object to be perforated by a perforating apparatus having a pair of roll-shaped cutters (see, for example, Patent Document 1 and Patent Document 2). In this perforating apparatus, a plurality of first cutting blades continuously provided in the circumferential direction are arranged in the circumferential direction on the circumferential surface of one roll-shaped cutter, and the axial direction is arranged on the circumferential surface of the other rolled cutter. A plurality of second cutting blades provided continuously are arranged in the circumferential direction. By using this punching device, a sheet as a punched object is sandwiched between a pair of roll-shaped cutters, and the pair of roll-shaped cutters are rotated in directions opposite to each other, whereby the first cutting blade and the second cutting blade are The sheet is perforated at the intersection.

International Publication No. 2012/096020 French Patent Application Publication No. 1375711

  By the way, when processing a perforated film, tension may be applied in the length direction of the film or the width direction of the film. For example, tension may be applied in the longitudinal direction (MD: Machine Direction) of the film in laminating, coating, slitting, bag making, filling, molding, and the like. Moreover, in order to prevent the sealing failure which arises at the time of the heat seal at the time of sealing a filler, tension may be provided to the width direction (TD: Transverse Direction) of a film.

  In the perforated film formed by the perforating apparatus according to the examples described in Patent Document 1 and Patent Document 2, since the holes and the blade traces are arranged along the longitudinal direction and the width direction, the tensile force in the longitudinal direction and the width direction is determined. The strength is small. For this reason, when a tension is applied in the longitudinal direction or the width direction, the applied hole may tear and become larger, or the perforated film may break, resulting in a larger gas permeability than the designed perforated film. .

  Then, this invention aims at providing the perforated film which has a structure which can improve the tensile strength in a longitudinal direction or the width direction, without impairing gas permeability.

  A perforated film according to one aspect of the present invention is a perforated film provided with a plurality of holes. Each of the plurality of holes includes a first cut made on the plurality of first imaginary lines extending along the first direction, and a second cut made on the plurality of second imaginary lines extending along the second direction. The first direction is different from the width direction and the direction orthogonal to the width direction.

  As described above, tension may be applied to the perforated film in the width direction or the longitudinal direction in a processing step or the like. For this reason, in the perforated film, if the cuts and the holes are arranged along the width direction and the longitudinal direction, the tensile strength in that direction is lowered, so that breakage is likely to occur in the processing step or the like. On the other hand, according to the perforated film of one aspect of the present invention, the plurality of holes are arranged at the intersections of the first cut made on the first imaginary line and the second cut made on the second imaginary line. Therefore, they are arranged along the first imaginary line and the second imaginary line. And since the 1st imaginary line is prolonged in the 1st direction different from the direction (longitudinal direction) orthogonal to the width direction and the width direction, the arrangement of the hole along the 1st imaginary line is the width direction and the longitudinal direction. It is inclined with respect to it. Moreover, since the arrangement of the holes along the second imaginary line is different from at least the width direction and the longitudinal direction, the width direction and the longitudinal direction are compared with the configuration in which the holes are arranged along the width direction and the longitudinal direction. Among them, the tensile strength in a direction different from the second direction is improved. As a result, when a tension is applied in a direction different from the arrangement direction of the holes in the width direction and the longitudinal direction, the occurrence of breakage can be suppressed and workability can be improved. Further, the distance between two holes adjacent to each other along the first imaginary line and the distance between two holes adjacent to each other along the second imaginary line are arranged along the width direction and the longitudinal direction. In the case where the distance between two adjacent holes is the same, the number of holes per specified area (perforation rate) is not reduced.

  The second direction may be different from the width direction and the direction orthogonal to the width direction. In this case, the first imaginary line extends in the first direction different from the width direction and the direction orthogonal to the width direction (longitudinal direction), and the second imaginary line is the width direction and the direction orthogonal to the width direction (longitudinal direction). Since they extend in different second directions, the array of holes along the first imaginary line and the array of holes along the second imaginary line are inclined with respect to the width direction and the longitudinal direction. For this reason, since the arrangement of the holes in the perforated film is inclined with respect to both the width direction and the longitudinal direction, the width direction is compared with the configuration in which the holes are arranged along the width direction and the longitudinal direction. And the tensile strength in the longitudinal direction is improved. As a result, when a tension is applied in the width direction and the longitudinal direction, the occurrence of breakage can be suppressed, and the workability can be further improved.

  The first direction is inclined at an angle greater than 30 ° and less than 60 ° with respect to the width direction, and the second direction is inclined at an angle greater than 30 ° and less than 60 ° with respect to the width direction. May be. Since the first imaginary line extends in a first direction that is inclined at an angle greater than 30 ° and smaller than 60 ° with respect to the width direction, the first incision along the first imaginary line and the hole The array is inclined at an angle larger than 30 ° and smaller than 60 ° with respect to the width direction. Further, the second cuts along the second imaginary line and the arrangement of the holes also extend in the second direction inclined at an angle larger than 30 ° and smaller than 60 ° with respect to the width direction. For this reason, the tensile strength in the width direction and the longitudinal direction is improved by stress relaxation as compared with a configuration in which cuts and holes are arranged except for the above range. As a result, when a tension is applied in the width direction and the longitudinal direction, the occurrence of breakage can be suppressed, and the workability can be further improved. Further, since the tensile strength has been improved, the shape and size of the holes can be maintained in a uniform state, so that the amount of gas transmitted from the perforated film can be prevented from deviating from the design value.

  In the first direction, the ratio between the first cut length α and the hole diameter γ is 0 <α / γ ≦ 500, and in the second direction, the ratio between the second cut length β and the hole diameter γ. May be 0 <β / γ ≦ 500. By setting the lengths of the first cut and the second cut in the above range with respect to the diameter of the hole, it is possible to suppress a decrease in tensile strength when tension in the width direction and the longitudinal direction is applied. As a result, the occurrence of breakage during processing can be suppressed, and the workability can be further improved.

  The difference between the first angle that is the inclination angle with respect to the width direction of the first imaginary line and the second angle that is the inclination angle with respect to the width direction of the second imaginary line may be -5 ° or more and + 5 ° or less. In this case, since the holes are arranged symmetrically with respect to the width direction, the stability of the tensile strength of the perforated film is improved. As a result, when a tension is applied to the perforated film in the longitudinal direction, the hole shape and the deformation of the film can be reduced.

  The first virtual line and the second virtual line may be orthogonal. Even in this case, when tension is applied in a direction different from the arrangement direction of the holes in the width direction and the longitudinal direction, the occurrence of breakage can be suppressed, and the workability can be improved.

  The two holes arranged closest to each other among the plurality of holes may be arranged along a direction different from the width direction and the direction orthogonal to the width direction. The tensile strength in the perforated film decreases as the distance between two adjacent holes along the direction in which the tension is applied is smaller. For this reason, the fall of the tensile strength in the width direction and a longitudinal direction can be suppressed by arranging two holes arrange | positioned nearest along the direction different from the width direction and a longitudinal direction.

  According to the present invention, the tensile strength in the width direction and the longitudinal direction can be improved without impairing gas permeability.

It is a top view which shows roughly the structure of the perforated film which concerns on 1st Embodiment. It is a perspective view which shows roughly the structure of the manufacturing apparatus for manufacturing the perforated film of FIG. It is a perspective view for demonstrating the principal part of the manufacturing apparatus of FIG. (A) is an enlarged plan view schematically showing the hole in FIG. 1, and (b) is an enlarged perspective view schematically showing the hole in FIG. FIG. 5 is a partial cross-sectional view taken along line VV in FIG. The expanded sectional view of the recessed part periphery of a non-penetrating film is shown. (A) is a figure which shows arrangement | positioning of the hole in the perforated film of a comparative example, (b) is a figure which shows the example of arrangement | positioning of the hole in the perforated film of FIG. 1, (c) is another arrangement | positioning of the hole in the perforated film of FIG. It is a figure which shows an example. It is a top view which shows roughly the structure of the perforated film which concerns on 2nd Embodiment. It is a top view which shows roughly the structure of the perforated film which concerns on 3rd Embodiment. It is a top view which shows roughly the structure of the modification of the manufacturing apparatus of FIG. (A) is a figure which shows arrangement | positioning of the hole of the perforated film of Example 1, (b) is a figure which shows arrangement | positioning of the hole of the perforated film of Example 2, (c) is arrangement | positioning of the hole of the perforated film of Example 3. (D) is a figure which shows arrangement | positioning of the hole of the perforated film of the comparative example 1.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the description of the drawings, the same or equivalent elements will be denoted by the same reference numerals, and redundant description will be omitted.

[First Embodiment]
FIG. 1 is a plan view schematically showing a configuration of a perforated film according to the first embodiment. As shown in FIG. 1, the perforated film 1 is a long film extending in the direction A, and is provided with a plurality of holes 11. Direction A is the longitudinal direction (MD). A direction B orthogonal to the direction A is the width direction (TD). Perforated film 1 is, for example, permeation of vaporized substances such as insect repellent component permeation membrane, sterilization gas permeation such as ETO gas permeation membrane, permeation of perfume such as aroma component permeation membrane, content generation gas permeation such as fermented food gas permeable membrane It can be used for various purposes such as flexible substrates, filters, and steam removal during microwave cooking.

The perforated film 1 may be a roll-shaped wound body or a cut piece. The length and width of the perforated film 1 are not particularly specified, and are wound in facilities such as a film forming machine, a laminating machine, a slitting machine, and a filling machine that are manufactured and used in a roll-shaped wound body. It is preferable that the length and width can be set. As an example, if a roll-to-roll process using a slitting machine is performed, the length of the perforated film 1 is preferably 2000 m or less, and the width of the perforated film 1 is preferably 1500 mm or less. Moreover, the thickness of the perforated film 1 is, for example, about 6 μm to 200 μm. The perforation rate of the perforated film 1 can be set according to the application, and is, for example, about 1 × 10 ⁻⁶ to 1 × 10 ⁻¹ %. In the case of the perforated film 1 obtained by perforating about 1 × 10 ⁻³ % on a 40 μm biaxially oriented polypropylene film, the permeation film 1 has a nitrogen permeation amount of about 6.0 × 10 ⁶ cm ³ / m ² · day · atm. It is.

  Examples of the film material constituting the perforated film 1 include polyethylene terephthalate (PET), biaxially stretched nylon (ONy), biaxially stretched polypropylene (OPP), polyimide, ethylene-vinyl alcohol copolymer (EVOH), low Density polyethylene (LDPE), linear low density polyethylene (LLDPE), etc. may be used. In addition, as the perforated film 1, metal foil such as aluminum foil and copper foil, cellophane, paper, non-woven fabric and the like can be used.

  Perforated film 1 has one surface 1a and the other surface 1b opposite to one surface 1a. The perforated film 1 has a side 1c and a side 1d facing each other in the direction B (width direction). The side 1c and the side 1d extend along the direction A (longitudinal direction).

  The hole 11 is a hole penetrating the perforated film 1 and has, for example, a circular shape or a rectangular shape. The diameter of the hole 11 is, for example, about 10 μm to 0.2 mm (200 μm). The holes 11 are regularly arranged. Each of the holes 11 includes, for example, a plurality of cuts made on a plurality of imaginary lines VL1 (first imaginary lines) extending along the direction D1 (first direction) and a direction D2 (second direction). It is arranged at an intersection with a cut made on the virtual line VL2 (second virtual line) (the cut will be described later).

The direction D1 is different from the direction A and the direction B, and is inclined with respect to the direction B at an angle θ ₁ (first angle). That is, the virtual line VL1 is inclined at an angle theta ₁ with respect to the direction B. The direction D2 is different from the direction A and the direction B, and is inclined at an angle θ ₂ (second angle) on the opposite side to the direction in which the direction D1 is inclined with respect to the direction B. That is, the virtual line VL2 is inclined at an angle theta ₂ with respect to the direction B. Angle θ ₁ and angle θ ₂ are larger than 0 °, preferably smaller than 90 °, more preferably larger than 30 ° and smaller than 60 °. Further, the angle θ ₁ and the angle θ ₂ are the same or substantially the same, and the difference between the angle θ ₁ and the angle θ ₂ is, for example, about −5 ° to + 5 °. In the example of FIG. 1, the angle θ ₁ is 45 ° and the angle θ ₂ is 45 °. The virtual line VL1 and the virtual line VL2 are orthogonal to each other.

  The plurality of virtual lines VL1 are arranged at a constant pitch P1, and the pitch P1 is, for example, about 0.5 mm or more. The plurality of virtual lines VL2 are arranged at a constant pitch P2, and the pitch P2 is, for example, about 0.5 mm or more. In the example of FIG. 1, since the pitch P1 and the pitch P2 are the same, a plurality of squares are formed by the virtual line VL1 and the virtual line VL2. One diagonal of the square is along the direction A, and the other diagonal is along the direction B. The hole 11 is located at the apex of each square. Note that the pitch P1 and the pitch P2 are not limited to 0.5 mm or more, and may be set to less than 0.5 mm as necessary.

  FIG. 2 is a diagram schematically showing a configuration of a manufacturing apparatus 2 for manufacturing the perforated film 1. FIG. 3 is a diagram for explaining a main part of the manufacturing apparatus 2. As shown in FIGS. 2 and 3, the manufacturing apparatus 2 includes a roll cutter 21 and a roll cutter 22.

  The roll cutter 21 and the roll cutter 22 are cylindrical or columnar cutters. The roll cutter 21 and the roll cutter 22 are arranged to face each other. The axis of the roll cutter 21 and the axis of the roll cutter 22 are parallel to each other, and the roll cutter 21 and the roll cutter 22 are separated so as to sandwich the drilled object. Support portions 24 are provided at both ends of the roll cutter 21 in the axial direction, and the roll cutter 21 is supported by the frame 23 via the support portion 24 so as to be rotatable around the axis. Support portions 25 are provided at both ends of the roll cutter 22 in the axial direction, and the roll cutter 22 is supported by the frame 23 via the support portion 25 so as to be rotatable around the axis. The roll cutter 21 and the roll cutter 22 rotate in conjunction with each other, and the rotation direction C1 of the roll cutter 21 is opposite to the rotation direction C2 of the roll cutter 22.

A cutting blade 211 is provided on the peripheral surface of the roll cutter 21. The cutting blade 211 is continuously provided in the circumferential direction inclined at an angle θ ₁ with respect to the axial direction of the roll cutter 21, and a plurality of cutting blades 211 are provided at a pitch P 1. A cutting blade 221 is provided on the peripheral surface of the roll cutter 22. Cutting edge 221 is provided continuously inclined at an angle theta ₂ with respect to the axial direction of the roll cutter 22 in the circumferential direction, it is provided with a plurality at a pitch P2. The cutting blade 211 and the cutting blade 221 are inclined in the same direction with respect to the axial direction. Moreover, the cutting blade 211 and the cutting blade 221 may be intermittently given by the pitch P1 and the pitch P2, and may be given spirally.

  Next, an example of the manufacturing method of the perforated film 1 is demonstrated using FIGS. 4A is an enlarged plan view schematically showing the periphery of the hole 11, and FIG. 4B is an enlarged perspective view schematically showing the periphery of the hole 11. FIG. 5 is a partial cross-sectional view taken along line VV in FIG.

  As shown in FIG. 3, first, a film 10 that is an object to be punched is prepared. For example, as the film 10, a long film such as a roll film can be used. Then, one end of the film 10 is sandwiched between the roll cutter 21 and the roll cutter 22 of the manufacturing apparatus 2. At this time, the cutting blade 211 of the roll cutter 21 contacts the one surface 10 a of the film 10, and the cutting blade 221 of the roll cutter 22 contacts the other surface 10 b of the film 10. In this state, by rotating the roll cutter 21 and the roll cutter 22 in conjunction with each other, the film 10 is conveyed along the longitudinal direction of the film 10, and the film 10 is wound into a roll shape.

In the manufacturing apparatus 2, the cutting blade 211 is pressed against the one surface 10a of the film 10, and a line L1 that is a trace of the cutting blade 211 is formed on the one surface 10a. Further, the cutting edge 221 is pressed against the other surface 10b of the film 10, and a line L2 which is a trace of the cutting edge 221 is formed on the other surface 10b. Line L1, when viewed from the one surface 10a side of the film 10, inclined at an angle theta ₁ with respect to the width direction of the film 10 extends in the longitudinal direction of the film 10, is a plurality formed at a pitch P1. When viewed from the one surface 10 a side of the film 10, the line L < _b > ₂ is inclined at an angle θ < _b > ₂ on the side opposite to the direction in which the line L < _b > 1 is inclined with respect to the width direction of the film 10 and extends in the longitudinal direction of the film 10. A plurality of them are formed at the pitch P2.

  As shown in FIG. 4, in the vicinity of the portion where the cutting blade 211 and the cutting blade 221 intersect, that is, in the vicinity of the portion where the line L1 and the line L2 intersect in plan view, the film 10 has one surface 10a and the other surface 10b. Are simultaneously pressurized. Therefore, a cut (first cut) 11a is formed on one surface 10a of the film 10, and a cut (second cut) 11b is formed on the other surface 10b of the film 10. This cut 11a is a portion cut toward the other surface 10b, and the amount of cut gradually increases toward the portion where the cutting blade 211 and the cutting blade 221 intersect. The cut 11b is a portion cut toward the one surface 10a, and the amount of cut gradually increases toward a portion where the cutting blade 211 and the cutting blade 221 intersect. Since these cuts 11a and 11b have a shape in which the cut amount gradually increases, resistance and pressure loss when gas, liquid, and viscous body permeate are reduced, and gas permeability and liquid permeability are improved. The film 10 is penetrated in the thickness direction at the portion where the cutting blade 211 and the cutting blade 221 intersect to form the hole 11.

  Thus, the hole 11 is continuously formed in the film 10 in the part which the cutting blade 211 and the cutting blade 221 cross | intersect, and the perforated film 1 is produced. The line L1 formed in the manufacturing process of the perforated film 1 matches the virtual line VL1 (see FIG. 1), and the line L2 matches the virtual line VL2 (see FIG. 1).

  The cutting blade 211 provided on the circumference of the roll cutter 21 and the cutting blade 221 provided on the circumference of the roll cutter 22 abut on the film 10 at a portion where the line L1 and the line L2 intersect. For this reason, the pressure from the one surface 10 a of the film 10 and the pressure from the other surface 10 b are equally applied to the film 10. Thereby, irregularities such as burrs and burrs are less likely to occur in the vicinity of the hole 11, and the perforated film 1 having a flat surface can be obtained even after the hole 11 is formed. Even if the perforated film 1 is wound into a roll, wrinkles and bumps are not easily generated, the winding shape is good, no winding marks are formed, and a good product is obtained.

  Further, in order to maintain the film strength that can withstand the tension during processing, the ratio of the length 11 of the cut 11a and the diameter γ of the hole 11 is preferably in the range of 0 <α / γ ≦ 500. The ratio of the length β of the cut 11b and the diameter γ of the hole 11 is preferably in the range of 0 <β / γ ≦ 500. Further, it is more preferable that 0 <α / γ ≦ 300 and 0 <β / γ ≦ 300. The cuts 11a and 11b always occur when the manufacturing apparatus 2 shown in FIG. 2 is used. When α / γ or β / γ is larger than 500, the length of the cut 11a or 11b becomes larger than the diameter γ of the hole 11. In this case, the distance between the cuts 11a or the cuts 11b made in the adjacent holes 11 is reduced, and the cuts 11a or the cuts 11b are easily connected during processing. Therefore, there is a possibility that the induction rate of film breakage is increased.

  Further, as shown in FIG. 5, the hole 11 is located between the cut 11a located on the one surface 10a side of the film 10, the cut 11b located on the other surface 10b side, and the cut 11a and the cut 11b. And a region 11c. The cut 11a, the cut 11b, and the region 11c communicate with each other. When the thickness direction of the film 10 is a direction C, the center of the cut 11a, the center of the cut 11b, and the center of the region 11c may overlap each other along the direction C.

  The notch 11a has a shape that opens on one surface 10a of the film 10 and widens from the other surface 10b side toward the one surface 10a. At least one cross section of the cut 11a is widened so as to draw a substantially circular arc shape from the other surface 10b side toward the one surface 10a. The notch 11a may be located on the one surface 10a side rather than the thickness direction center side of the film 10. The maximum depth of the cut 11a is, for example, about 0.5 μm to 100 μm. The diameter d1 which is the maximum diameter of the cut 11a along the direction D1 is, for example, about 100 μm to 6000 μm. The diameter d2 that is the minimum diameter of the cut 11a along the direction D1 is, for example, about 0.5 μm to 200 μm.

  The cut 11b has a shape that opens to the other surface 10b and expands from the one surface 10a side toward the other surface 10b. At least one cross section of the notch 11b extends so as to draw a substantially trapezoidal cross section from the one surface 10a side toward the other surface 10b. The cut 11b may be located on the other surface 10b side than the thickness direction center side of the film 10. The maximum depth of the cut 11b is, for example, about 0.5 μm to 100 μm. The diameter d3 that is the maximum diameter of the cut 11b along the direction D1 is, for example, about 50 μm to 3000 μm, and is shorter than the diameter d1 of the cut 11a. The diameter d4 that is the minimum diameter of the cut 11b along the direction D1 is, for example, about 0.5 μm to 200 μm.

  The region 11c is located between the cut 11a and the cut 11b in the direction C and has a substantially rectangular cross section. The region 11c has, for example, a rectangular parallelepiped shape, a cubic shape, or various polyhedrons. The depth of the region 11c is, for example, about 0.1 μm to 100 μm. The diameter d5 of the region 11c along the direction D1 is, for example, about 2 μm to 200 μm. The diameter d3 of the region 11c is substantially the same as the diameter d2 of the cut 11a and the diameter d4 of the cut 11b.

  The above is the description of the perforated film 1 in which the holes 11 are provided in the film 10. However, even if a non-penetrating film having a plurality of recesses (hereinafter referred to as a non-penetrating film) is manufactured without forming the region 11c. Good. FIG. 6 shows an enlarged cross-sectional view around the recess of the non-penetrating film.

  As shown in FIG. 6, the non-penetrating film 1 </ b> Z is formed by forming a large number of fine linear concave portions on the film 10. By increasing the clearance between the support portions 24 provided at both ends of the roll cutter 21 shown in FIG. 2 and the support portions 25 provided at both ends of the roll cutter 22, the non-penetrating film 1Z can be manufactured. The shape of the recess in the non-penetrating film 1Z is such that the film 10 has one surface 10a and the other in the vicinity of the portion where the cutting blade 211 and the cutting blade 221 intersect, that is, the portion where the line L1 and the line L2 intersect in plan view. Pressure is applied simultaneously from the direction 10b. For this reason, the notch 11d is formed in the one surface 10a of the film 10, and the notch 11e is formed in the other surface 10b of the film 10. The cut 11d is a portion cut toward the other surface 10b, and the cut amount gradually increases toward a portion where the cutting blade 211 and the cutting blade 221 intersect. The cut 11b is a portion cut toward the one surface 10a, and the amount of cut gradually increases toward a portion where the cutting blade 211 and the cutting blade 221 intersect. The cut 11d made from one surface 10a of the film 10 and the cut 11e made from the other surface 10b are not in contact with each other, and the film 10 remains in the thickness direction. That is, a hole penetrating in the thickness direction is not formed in the film 10. In the non-penetrating film 1Z, the cut 11d is formed as a recess on the one surface 10a, and the cut 11e is formed as a recess on the other surface 10b.

  The non-penetrating film 1Z is provided with a large number of fine linear recesses (cuts 11d, 11e), and can maintain the strength and tension that the film 10 originally has. In addition, by forming the recesses in the film 10, the wettability of the non-penetrating film 1Z is improved, and an anchor effect (throwing effect) is generated with respect to the coating liquid, adhesive, ink, etc., and the adhesiveness is improved. Can be done. Moreover, since the film 10 is non-penetrating, it is possible to improve gas permeability without allowing bacteria and bacteria to pass through. Moreover, since the non-penetrating film 1Z is also excellent in water pressure resistance, it can be developed for applications requiring waterproofness and moisture permeability.

  Furthermore, when a composite film formed by laminating a film having a large elastic deformation (for example, a PET film) and a film having a small elastic deformation (for example, an LLDPE film) is simultaneously pressed from one side and the other side, the elastic deformation Cuts occur in large films, and cuts do not easily occur in films with small elastic deformation. For this reason, it is possible to adjust gas permeability. For example, a PET film has a property that it is difficult to transmit oxygen and easily transmit water vapor. On the other hand, the LLDPE film has a property of being easily permeable to oxygen and hardly permeable to water vapor. Usually, by bonding the two kinds of films, a composite film having a property of hardly transmitting oxygen and water vapor is obtained. However, when a non-penetrating film in which only a plurality of cuts are made in only the PET film of the composite film, the film has a property of being easily permeable to oxygen and hardly permeable to water vapor. That is, a non-penetrating film capable of selectively permeating gas can be formed. Moreover, since the non-penetrating film is multilayered, it can be handled as a package, for example, like a bag or a container lid.

  Next, the function and effect of the perforated film 1 will be described. 7A is a diagram showing the arrangement of the holes 111 in the perforated film 100 of the comparative example, FIG. 7B is a diagram showing an example of the arrangement of the holes 11 in the perforated film 1, and FIG. It is a figure which shows the other example of arrangement | positioning of the hole 11 in the perforated film 1. FIG.

  As shown in FIG. 7A, in the perforated film 100, holes 111 are arranged at intersections of the plurality of virtual lines VL <b> 101 and the plurality of virtual lines VL <b> 102. The plurality of virtual lines VL101 extend along the direction A that is the longitudinal direction of the perforated film 100, and the plurality of virtual lines VL102 extend along the direction B that is the width direction of the perforated film 100. Further, the pitch of the virtual line VL101 and the pitch of the virtual line VL102 are equal to each other and S. In this perforated film 100, the distance between two holes 111 adjacent to each other along the direction A is S, and the distance between two holes 111 adjacent to each other along the direction B is S.

As shown in FIG. 7B, in the perforated film 1, the plurality of virtual lines VL <b> 1 are different from the direction A that is the longitudinal direction of the perforated film 1 and the direction B that is the width direction of the perforated film 1. The plurality of virtual lines VL2 extend along a direction D2 different from the direction A and the direction B. The virtual line VL1 is inclined at 45 ° with respect to the direction B. The virtual line VL2 is inclined at 45 ° on the opposite side to the direction in which the virtual line VL1 is inclined with respect to the direction B. The virtual line VL1 and the virtual line VL2 are orthogonal to each other. In addition, the pitch P1 of the virtual line VL1 and the pitch P2 of the virtual line VL2 are equal to each other and S. In this perforated film 1, the distance between the two holes 11 adjacent to each other along the direction A is 2 ^1/2 × S, and the distance between the two holes 11 adjacent to each other along the direction B is 2 ^1/2 × S. It becomes. Therefore, in the perforated film 1, compared to the perforated film 100, the distance between the two holes 11 adjacent to each other along the direction A and the direction B can be increased. For this reason, the perforated film 1 can improve the tensile strength in the longitudinal direction and the width direction as compared with the perforated film 100. On the other hand, the number of holes (perforation rate) per specified area of the perforated film 1 is the same as the perforation rate of the perforated film 100. Therefore, the perforated film 1 has the same gas permeability (breathability) as the perforated film 100.

  As shown in FIG. 7C, in the perforated film 1, the virtual line VL1 is inclined with respect to the direction B at an angle θ (30 ° <θ <60 °), and the virtual line VL2 is in the direction B. On the other hand, when the virtual line VL1 is inclined at an angle θ opposite to the direction in which the virtual line VL1 is inclined, the distance between the two holes 11 adjacent to each other along the direction A is 2Ssinθ, and 2 adjacent to each other along the direction B. The distance between the two holes 11 is 2S cos θ. When the angle θ is larger than 30 °, the distance between the two holes 11 adjacent to each other along the direction A is larger than S, so that the two adjacent to each other along the direction A compared to the perforated film 100. The distance between the holes can be increased. For this reason, it becomes possible to improve the tensile strength in the longitudinal direction as compared with the perforated film 100.

  Further, when the angle θ is smaller than 60 °, the distance between the two holes 11 adjacent to each other along the direction B is larger than S, so that they are adjacent to each other along the direction B as compared with the perforated film 100. The distance between the two holes can be increased. For this reason, it becomes possible to improve the tensile strength in the width direction as compared with the perforated film 100. From the above, in the perforated film 1, when the angle θ is larger than 30 ° and smaller than 60 °, two holes adjacent to each other along the direction A and the direction B are compared with the perforated film 100. , And the tensile strength in the longitudinal direction and the width direction can be improved. On the other hand, the perforation rate of the perforated film 1 is 1 / sin 2θ (> 1) times the perforation rate of the perforated film 100. For this reason, in the perforated film 1, since the perforation rate is increased with respect to the perforated film 100, the gas permeability (breathability) can be improved.

  Further, when the pitch P1 and the pitch P2 are adjusted so that the gas permeability of the perforated film 1 is approximately the same as the gas permeability of the perforated film 100, the pitch P1 and the pitch P2 are the pitch of the virtual line VL101 of the perforated film 100. And the pitch of the virtual line VL102 is larger. For this reason, since the distance between the adjacent holes 11 can be further increased, the tensile strength in the longitudinal direction and the width direction can be further improved.

  As described above, in the perforated film 1, the plurality of holes 11 are arranged along the virtual line VL1 and the virtual line VL2. Since the virtual line VL1 extends in the direction D1 different from the direction A and the direction B and the virtual line VL2 extends in the direction D2 different from the direction A and the direction B, the arrangement of the holes 11 along the virtual line VL1 and the virtual line The arrangement of the holes 11 along the VL2 is inclined with respect to the direction A and the direction B. Further, the distance between the two holes 11 adjacent to each other along the direction A is larger than that of the perforated film 100 shown in FIG. The distance is large compared to the perforated film 100. For this reason, in the perforated film 1, the tensile strength in the direction A and the direction B is improved. As a result, when a tension is applied in the direction A and the direction B, the occurrence of breakage can be suppressed and workability can be improved.

In perforated film 1, and the angle theta ₁ is an inclined angle relative to the direction B of the virtual line VL1, the difference between the angle theta ₂ is a tilt angle with respect to the direction B of the virtual line VL2 is -5 ° to + 5 ° or less. In this case, since the holes 11 are arranged symmetrically with respect to the direction B, the stability of the tensile strength of the perforated film 1 is improved. As a result, when a tension is applied to the perforated film 1 in the direction A, the hole shape and the deformation of the film can be reduced.

[Second Embodiment]
FIG. 8 is a plan view schematically showing the configuration of the perforated film according to the second embodiment. As shown in FIG. 8, the perforated film 1A is different from the perforated film 1 of the first embodiment described above in the direction D2 in which the plurality of virtual lines VL2 extend.

The direction D2 is the same direction as the direction B. That is, the plurality of virtual lines VL2 extend along the direction B. And the virtual line VL1 and the virtual line VL2 intersects at an angle theta _1. The angle θ ₁ is larger than 0 ° and smaller than 90 °. The angle θ ₁ may be 10 ° or more in order to improve the tensile strength in the length direction, and may be 80 ° or less in order to improve the tensile strength in the width direction. For this reason, a plurality of parallelograms are formed by the virtual line VL1 and the virtual line VL2. The hole 11 is located at the apex of each parallelogram.

  By changing the shape of the cutting edge 221 of the roll cutter 22 in the manufacturing apparatus 2, the perforated film 1A is obtained. More specifically, in the manufacturing apparatus 2 for the perforated film 1A, the cutting blades 221 of the roll cutter 22 are provided continuously in the axial direction of the roll cutter 22, and a plurality of them are provided at a pitch P2 in the circumferential direction. .

  In the above perforated film 1A, since the virtual line VL1 extends in the direction D1 different from the direction A and the direction B, the arrangement of the holes 11 along the virtual line VL1 is inclined with respect to the direction A and the direction B. Yes. For this reason, since the arrangement of the holes 11 in the perforated film 1A is inclined with respect to the direction A, the tensile strength in the direction A is improved as compared with the perforated film 100 shown in FIG. The As a result, when a tension is applied in the direction A, the occurrence of breakage can be suppressed, and workability can be improved.

Specifically, in the perforated film 1A, when the pitch P1 of the virtual line VL1 and the pitch P2 of the virtual line VL2 in the perforated film 1A are equal to the pitch of the virtual line VL101 and the virtual line VL102 in the perforated film 100, the direction B The distance between the two holes 11 adjacent to each other along the line is S / sin θ ₁ . For this reason, in the perforated film 1A, compared to the perforated film 100, the distance between two holes adjacent to each other along the direction B can be increased, and the tensile strength in the width direction can be improved.

  Further, in the perforated film 1A, since the holes 11 are not arranged along the direction A, when a tension is applied in the longitudinal direction, forces acting on the two adjacent holes 11 are dispersed. For this reason, it becomes possible to improve the tensile strength in the longitudinal direction as compared with the perforated film 100.

Further, the perforation rate of the perforated film 1 </ b> A is 1 / sin θ ₁ times (> 1) the perforation rate of the perforated film 100. For this reason, in the perforated film 1A, since the perforation rate is increased with respect to the perforated film 100, the gas permeability (breathability) can be improved.

[Third Embodiment]
FIG. 9 is a plan view schematically showing the configuration of the perforated film according to the third embodiment. As shown in FIG. 9, the perforated film 1B includes the perforated film 1 of the first embodiment described above in the direction D1 in which the plurality of virtual lines VL1 extend, the direction D2 in which the plurality of virtual lines VL2 extend, the pitch P1, and the pitch P2. Is different.

Direction D1 is different from the direction A and direction B, and inclined at an angle theta ₁ with respect to the direction B. That is, the virtual line VL1 is inclined at an angle theta ₁ with respect to the direction B. Direction D2 is different from the direction A and direction B, and inclined at an angle theta ₂ to the side opposite to the direction in which the direction D1 is tilted with respect to the direction B. That is, the virtual line VL2 is inclined at an angle theta ₂ with respect to the direction B. The angle θ ₁ and the angle θ ₂ are larger than 30 ° and smaller than 60 °. The angle θ ₁ and the angle θ ₂ may be 10 ° or more in order to improve the tensile strength in the longitudinal direction, and may be 80 ° or less in order to improve the tensile strength in the width direction. Further, the angle θ ₁ and the angle θ ₂ are different.

  The plurality of virtual lines VL1 are arranged at regular intervals, and the pitch P1 is, for example, about 0.5 mm or more. The plurality of virtual lines VL2 are arranged at regular intervals, and the pitch P2 is, for example, about 0.5 mm or more. The pitch P1 and the pitch P2 are different. For this reason, a plurality of parallelograms are formed by the virtual line VL1 and the virtual line VL2. The hole 11 is located at the apex of each parallelogram. Note that the pitch P1 and the pitch P2 are not limited to 0.5 mm or more, and may be set to less than 0.5 mm as necessary.

By changing the angle theta ₂ of the cutting edge 221 of the angle theta ₁ and roll cutter 22 of the cutting edge 211 of the roll cutter 21 in the manufacturing apparatus 2 at a desired angle, perforated film 1B is obtained.

  Even with the above perforated film 1B, the same effects as the perforated film 1 described above are exhibited.

  In addition, the perforated film which concerns on this invention is not limited to the said embodiment. For example, in the perforated films 1 and 1B, the two holes 11 arranged closest to each other among the plurality of holes 11 may be arranged along a direction different from the direction A and the direction B. The tensile strength in the perforated films 1 and 1B decreases as the distance between the two holes 11 adjacent to each other along the direction in which the tension is applied decreases. For this reason, the fall of the tensile strength in the direction A and the direction B can be suppressed by arranging the two holes 11 arranged closest to each other along a direction different from the direction A and the direction B.

In the perforated film 1A and the perforated film 1B, the pitch P1 and the pitch P2 may be the same or different. In the perforated film 1B, the angle θ ₁ and the angle θ ₂ may be the same or different.

  Moreover, it is good also as a multilayer film by laminating the perforated film 1,1A, 1B. That is, it is good also as a multilayer film by bonding the perforated film 1 to a non-perforated film.

  As shown in FIG. 10, the manufacturing apparatus 2 may include a plurality of sets of roll cutters 21 and roll cutters 22 arranged in the axial direction. The plurality of sets of roll cutters 21 and roll cutters 22 may be arranged in a staggered manner along the axial direction. That is, each set of the roll cutter 21 and the roll cutter 22 may be alternately arranged on two lines extending along the axial direction. According to this manufacturing apparatus 2, a perforated film 1 having a hole 11 having the same hole diameter and having a larger width can be obtained. For example, when a pair of long roll cutters and roll cutters having a relatively small diameter are used, the perforated film is deformed by a load acting on the pair of roll cutters, and the perforated film is bent. This is because the amount of deflection of the perforated film is inversely proportional to the fourth power of the roll diameter of the roll cutter. In order to reduce the amount of deflection of the perforated film, it is necessary to increase the roll diameter of the roll cutter. When a roll cutter with a large diameter is prepared, it is conceivable that it is difficult to secure the installation space for the roll cutter even if it is to be attached to existing equipment. In addition, when a roll cutter having a large diameter is used, a set of roll cutters may be distorted by its own weight. In this case, a difference occurs in the pressure when the film is nipped. As a result, there is a difference in the size of the holes formed in the film between the center and the end of the roll cutter, which may affect the gas permeability of the perforated film. On the other hand, by providing a plurality of sets of roll cutters 21 and roll cutters 22, the diameter of at least one of the roll cutters 21 and 22 can be reduced and the roll width can be reduced. Thereby, the roll cutters 21 and 22 can be made compact, and it becomes easy to attach to a part of existing manufacturing equipment. Moreover, the distortion of the roll cutter 21 and the roll cutter 22 can be reduced, and the formation accuracy of the hole 11 can be improved. Further, by reducing one of the roll cutters 21 and 22, the lengths of the cuts 11a and 11b applied to the film 10 can be reduced. Thereby, reduction of film strength can be controlled.

  Next, examples of the present invention will be described. The present invention is not limited to the following examples.

  11A is a diagram showing the arrangement of the holes in the perforated film of Example 1, FIG. 11B is a diagram showing the arrangement of the holes in the perforated film of Example 2, and FIG. FIG. 11D is a diagram showing the arrangement of holes in the perforated film of Example 3, and FIG. 11D is a diagram showing the arrangement of holes in the perforated film of Comparative Example 1.

[Example 1]
As shown in (a) of FIG. 11, the perforated film of Example 1, and the virtual line VL1 that is inclined at an angle theta ₁ with respect to TD, opposite to the direction in which the virtual line VL1 is inclined with respect TD and the virtual line VL2 which is tilted at an angle theta _2, intersection holes 11 are arranged in. The pitch P1 of the virtual line VL1 is 5 mm, the pitch P2 of the virtual line VL2 is 5 mm, the angle θ ₁ is 45 °, and the angle θ ₂ is 45 °.

[Example 2]
As shown in (b) of FIG. 11, the perforated film of Example 2, and the virtual line VL1 that extends along the MD, and the virtual line VL2 inclined at an angle theta ₂ with respect to TD, intersection hole 11 Arranged. Pitch P1 of the virtual line VL1 is 5 mm, the pitch P2 of the virtual line VL2 was 5 mm, the angle theta ₂ and 45 °. That is, the angle θ ₁ formed by the virtual line VL1 and TD is 90 °.

[Example 3]
As shown in (c) of FIG. 11, the perforated film of Example 3, a virtual line VL1 that is inclined at an angle theta ₁ with respect to TD, opposite to the direction in which the virtual line VL1 is inclined with respect TD and the virtual line VL2 which is tilted at an angle theta _2, intersection holes 11 are arranged in. The pitch P1 of the virtual line VL1 is 5 mm, the pitch P2 of the virtual line VL2 is 5 mm, the angle θ ₁ is 45 °, and the angle θ ₂ is 60 °.

[Comparative Example 1]
As shown in (d) of FIG. 11, in the perforated film of Comparative Example 1, holes 111 were arranged at the intersections of the virtual line VL101 extending along MD and the virtual line VL102 extending along TD. The pitch P1 of the virtual line VL101 is 5 mm, and the pitch P2 of the virtual line VL102 is 5 mm. In other words, the angle theta ₁ is 90 ° formed between the virtual line VL101 and TD is, the angle theta ₂ formed between imaginary line VL102 and TD are is 0 °.

(1) Appropriate evaluation of perforation processing Using a perforation apparatus equipped with a roll blade capable of perforation processing according to Examples 1 to 3 and Comparative Example 1, the hole diameter is set to 10 μm, and the film is perforated. The speed during processing and the presence or absence of film breakage were confirmed. As a film to be processed, a polyethylene terephthalate (PET) film having a thickness of 12 μm and a biaxially oriented polypropylene (OPP) film having a thickness of 30 μm were used.

The determination method is as follows.
A: Processing is possible at a processing speed of 80 m / min or more. ○: Processing is possible at a processing speed of less than 80 m / min. Δ: Processing is possible at a processing speed of less than 40 m / min. X: Processing is possible at a processing speed of less than 20 m / min. Cannot be processed due to breakage

  As shown in Table 1, when a PET film having a thickness of 12 μm was used as Comparative Example 1, breakage was likely to occur and drilling could not be performed. Further, when an OPP film having a thickness of 30 μm was used as Comparative Example 1, although punching was possible, the film was broken at a processing speed of 40 m / min or more. On the other hand, in Examples 1 to 3, no breakage occurred when any film was used, and drilling could be performed without any problem even at a processing speed of 80 m / min or more.

(2) Measurement of hole diameter after drilling The actual hole diameter of the OPP film punched by setting the hole diameter to 10 μm in (1) was measured using a microscope.

(3) Tensile strength evaluation The tensile strength of MD and TD was measured according to JIS K7127. As the film to be measured, the OPP film that was perforated by the above-described perforation processing appropriate evaluation was used. The unperforated OPP film had a MD tensile strength of 50 N / 15 mm and a TD tensile strength of 75 N / 15 mm.

(4) Gas permeability evaluation The oxygen permeability and water vapor permeability of the OPP film perforated in (1) were measured. The oxygen permeation of the unperforated OPP film is 1000 cc / m ² · day · atm, and the water vapor permeability is 5 g / m ² · day.

  As shown in Table 2, when the actual hole diameter was measured, Examples 1 to 3 had a hole diameter almost as set. On the other hand, in Comparative Example 1, the actual hole diameter was about four times as large as the set 10 μm. In Comparative Example 1, it is considered that the hole was torn during drilling and the hole diameter was increased. In Comparative Example 1, both MD and TD had low tensile strength, which was about 70% lower than that of the unperforated OPP film. In Example 1 and Example 3, the tensile strength of MD and TD was reduced by about 30% compared to the unperforated OPP film. In Example 2, holes are arranged along the MD. For this reason, in Example 2, although the tensile strength of TD was low, the tensile strength of MD was substantially equivalent to Example 1 and Example 3.

  When oxygen permeability and moisture permeability were measured, Examples 1 to 3 had permeability according to the perforated area. On the other hand, although Comparative Example 1 had the same perforation area as Example 1, it had a permeability of about 3 times or more. Also from this result, it is considered that the hole diameter was large in Comparative Example 1.

  According to the above evaluation results, each of Examples 1 to 3 is more suitable for drilling than Comparative Example 1, can reproduce the designed hole diameter and gas permeability, and has a high MD tensile strength. It was confirmed. Moreover, in Example 1 and Example 3, it was confirmed that the tensile strength of TD is larger than Comparative Example 1. According to the first to third embodiments, the distance between the two holes 11 adjacent to each other along the MD can be made larger than the distance between the two holes 111 adjacent to each other along the MD in the comparative example 1. . As a result, it is possible to improve perforation processing appropriateness and MD tensile strength. According to Example 1 and Example 3, the distance between the two holes 11 adjacent to each other along the TD can be made larger than the distance between the two holes 111 adjacent to each other along the TD in the comparative example 1. . As a result, the tensile strength of TD can be improved.

(5) Gas permeability measurement of a perforated film and a non-penetrating film A perforated film in which a through hole having a hole diameter of 10 μm and a cutting length of 100 μm is provided in the same position as in Example 1 on a 30 μm thick OPP film, and the thickness direction An oxygen permeability and a water vapor permeability were measured using a non-penetrating film having a cut length of 100 μm provided with a non-penetrating region of about 5 μm. The raw OPP film has an oxygen permeability of 1000 cc / m ² · day · atm, and a water vapor permeability of 5 g / m ² · day.

  As shown in Table 3, since the perforated film has through holes compared to the unprocessed film, high gas permeability is shown. Moreover, although the non-penetrating film was not provided with through holes, the non-penetrating film had higher gas permeability than the unprocessed film.

  According to the above evaluation results, it was confirmed that the gas permeation amount can be controlled by providing a through hole or providing a non-penetrating region in the film. Further, by controlling the length of the non-penetrating region of the non-penetrating film, it is possible to further adjust the gas permeability according to the use and purpose.

1, 1A, 1B ... perforated film, 11 ... hole, 11a ... cut (first cut), 11b ... cut (second cut), A ... direction, B ... direction (width direction), D1 ... direction (first direction) ), D2 ... direction (second direction), VL1 ... virtual line (first virtual line), VL2 ... virtual line (second virtual line), θ ₁ ... angle (first angle), θ ₂ ... angle (second) Angle), α, β ... length, γ ... diameter.

Claims (6)

A perforated film provided with a plurality of holes,
Each of the plurality of holes includes a first cut made on a plurality of first imaginary lines extending along a first direction and a second cut made on a plurality of second imaginary lines extending along a second direction. Placed at the intersection of
Said first direction, unlike the direction perpendicular to the width direction and the width direction,
The second direction, that is different from the direction perpendicular to the width direction and the width direction, perforated film. The first direction is inclined at an angle larger than 30 ° and smaller than 60 ° with respect to the width direction;
The second direction is inclined at an angle larger than 30 ° and smaller than 60 ° with respect to the width direction.
The perforated film according to claim 1 . In the first direction, the ratio of the first cut length α and the hole diameter γ is 0 <α / γ ≦ 500,
In the second direction, the ratio of the length β of the second cut and the diameter γ of the hole is 0 <β / γ ≦ 500.
The perforated film according to claim 1 or 2 . A difference between a first angle that is an inclination angle of the first imaginary line with respect to the width direction and a second angle that is an inclination angle of the second imaginary line with respect to the width direction is −5 ° to + 5 °. ,
The perforated film as described in any one of Claims 1-3 . The first virtual line and the second virtual line are orthogonal to each other,
The perforated film as described in any one of Claims 1-4 . The two holes arranged closest to each other among the plurality of holes are arranged along a direction different from the width direction and a direction orthogonal to the width direction.
The perforated film according to any one of claims 1 to 5 .

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