JP2007098628A - Laminated film for minute boring - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a laminated film for minute boring which is excellent in boring process aptitude and boring accuracy even when a plastic film to be bored is thin, or initial tensile stress is weak and can smoothly obtain a bored film without the adhesion of a contaminant such as an adhesive and a method for producing the bored film using the laminated film. <P>SOLUTION: A substrate sheet is laminated on at least one side of the plastic film to be bored whose initial tensile stress per 15 mm width is 1.0 N/% or below through an adhesive layer easily soluble in water to make the laminated film for minute boring whose initial tensile stress per 15 mm width is at least 1.2 N/%. After boring is carried out in a state of the laminated film, an aqueous solvent is acted on the adhesive layer, the adhesive layer is dissolved, and a bored film layer is isolated. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

The present invention relates to a laminated film. More specifically, the present invention relates to a plastic film having a small initial tensile stress (hereinafter abbreviated as a plastic film to be perforated) to be perforated through an easily water-soluble adhesive layer. The present invention relates to a laminated film for fine perforation in which a base sheet is laminated to reinforce an initial tensile stress.

In general, many plastic films are transparent, water and solvent resistant, and are useful as various packaging materials and structural materials because air and liquid permeation are blocked. However, depending on the application, water resistance and solvent resistance may be required, but liquid permeability and air permeability may be required. For example, agricultural house films, separator films used inside fuel cells, ions For applications such as base materials and core materials such as exchange membranes, a perforated film obtained by appropriately perforating a water-resistant or solvent-resistant plastic film is used.

  Among the above-mentioned typical perforated films [hereinafter abbreviated as perforated films], in the case of house films, generally inexpensive polyethylene and polypropylene films are used, and the thickness is thick and the structural strength is high. It is not necessarily required to be large and have high drilling accuracy. Therefore, as a drilling method, for example, if the required hole diameter is formed substantially evenly, it can be used practically. There are a method of pressurizing and punching a transparent synthetic resin film selected in advance on a needle roll in which a forming needle to be pierced is implanted, and a hole forming pin heated at a predetermined interval. It is disclosed that a mass production method such as a method of forming a hole by bringing it into contact with an implanted hole pin planting roll can be applied. (Patent Document 1)

  On the other hand, in the case of the separator film and core material used inside the fuel cell, the position and shape of the perforations greatly affect the characteristics of the fuel cell. In order to further improve the performance as a battery, the separator A film or the like that is as thin as possible is required. As a typical example, fine holes having a diameter of 0.1 to 0.5 mm are tightly perforated on the entire surface of a PPS (polyphenylene sulfide) film having a thickness of 10 to 20 μm, for example. In such a case, as a method for punching a large number of holes in a sheet, for example, a laser method, a drill method, a press method using a concavo-convex mold or the like is known, and a hole shape is accurately punched in a plastic film. As a method, a pressing method using a concavo-convex mold that combines a convex mold in which thin rods having a cross-sectional shape in a hole are usually arranged at a perforation position and a concave mold placed on the back of the film to be perforated is preferable. Applied. Since it takes time and cost to manufacture such a complex and high-precision concavo-convex mold, practically using a press machine with one or a small number of concavo-convex cavities to move the position of the mold In some cases, a predetermined array of perforations is performed.

  In that case, when the thickness of the plastic film to be perforated is thin or the initial tensile stress is small, pulling wrinkles are likely to occur during handling, and when trying to perforate continuously while unwinding from the winding roll through the perforating device, If the film surface is stretched by the tension applied to the plastic film to be perforated and the film surface is waved, or if the paper is passed with a weak tension to avoid this, the plastic film to be perforated swings in the width direction. In particular, when the mold uses a pair of concave and convex molds and the mold position is moved in the width direction and the length direction of the film to perforate at a specified position, such a thin plastic film to be perforated is In this way, not only does the drilling position become a predetermined position and there is no commercial value at all, but the convex mold is pushed down during each drilling cycle. Thereafter, when the convex mold is pulled up, the thin plastic film is pulled by the convex bar and lifts up and moves up and down, so that the perforation operation cannot be continued smoothly. As a method of avoiding such behavior, a method of concealing defects due to this thinness only at the time of drilling by laminating a carrier film etc. on the back of a thin plastic film to reinforce the thickness and tensile stress, and a method of peeling after drilling is conceived. The

The carrier film is formed by forming a pressure-sensitive adhesive on the surface of the base sheet, and is attached to the back surface of the plastic film to be perforated through the pressure-sensitive adhesive layer to reinforce it. In this case, since the plastic film to be perforated is thin when the carrier film is peeled and removed after perforation, it is easy for wrinkles to occur due to the stress due to the peel strength. About this point, depending on the thickness of the plastic film to be perforated, it can be avoided to some extent by adjusting the peeling strength (lightness at the time of peeling) of the pressure-sensitive adhesive layer of the carrier film to be low.

However, the carrier film adhesive is generally an acrylic, urethane, or silicone adhesive, and the adhesive protrudes into the inside of the hole when perforated, or the carrier of the perforated film upon peeling after perforation. Part of the adhesive residue tends to remain on the film side surface, and it remains as an impurity in the fuel cell as a precision instrument. The above-mentioned pressure-sensitive adhesive is usually water-insoluble and cannot be dissolved and removed with an aqueous solvent, and even if it is water-soluble, it is not easily dissolved in an aqueous solvent and is dissolved under hot water conditions or immersed for a long time. It was necessary and not practical.
Japanese Patent Laid-Open No. 10-210870

The present invention solves the above-mentioned problems, and even when the thickness of the plastic film to be perforated is thin or when the initial tensile stress is small, the perforation process suitability and the perforation accuracy are excellent, and contamination such as an adhesive is present. Provided are a finely perforated laminated film capable of smoothly obtaining a perforated film without adhesion of a substance, and a method for producing a perforated film using the finely perforated laminated film.

  The first gist of the present invention is that a base sheet is laminated on one or both sides of a plastic film to be perforated having an initial tensile stress of 1.0 N /% or less per 15 mm width via a water-soluble adhesive layer. The initial tensile stress is 1.2 N /% or more per 15 mm width.

And the second gist of the present invention is characterized in that after the perforation treatment is performed in the state of the above laminated film, an aqueous solvent is allowed to act on the adhesive layer, and the perforated film layer is isolated by dissolving the adhesive layer. And a method for producing a perforated film.

  Even if the initial tensile stress per 15 mm width of the plastic film to be perforated is 1.0 N /% or less, the fine perforation according to the present invention in which a base sheet is laminated on one or both sides with a water-soluble adhesive The laminated film for use in this laminated film state is excellent in perforation process suitability and perforation accuracy by being perforated, and after perforation, an aqueous solvent is applied to the adhesive layer to dissolve the adhesive layer. The base sheet can be peeled and removed with almost no stress, and the remaining adhesive can be easily and completely removed by washing with an aqueous solvent such as water. A perforated film having no adhesion can be obtained smoothly.

The laminated film of the present invention is formed by laminating a base sheet on one or both sides of a plastic film to be perforated.

The material of the plastic film to be perforated is not particularly limited as long as it can be perforated by a perforation method described later. For example, polyolefin resins such as polyethylene and polypropylene; polyethylene terephthalate, polybutylene Polyester resins such as terephthalate and polyethylene naphthalate; Polyamide resins such as 6-nylon, 6-6 nylon and 6-12 nylon; Polyurethane resins; Polyacrylic resins; Fluorine resins; Silicone resins; Polyimide resins ; Polyphenylene resin: Rubber resin; Vinyl chloride resin; Other resins or those usually used as plastic films produced by blending these resins can be applied, and paper, cellophane, etc. Even materials that are water poor also include those subjected to water-resistant treatment of the extent to withstand water immersion.

The thickness of the plastic film to be perforated is not particularly limited as long as it can be perforated by a perforation method described later, but when the base sheet is perforated alone without being laminated. Is effective in the case of a thin plastic film to be perforated with an initial tensile stress per 15 mm width of 1.0 N /% (elongation) or less, and further 0.8 N /% (elongation) or less, which causes undulation in the perforation process. Is particularly prominent and has practical value. The thickness varies depending on the material constituting the plastic film to be perforated, but is generally 40 μm or less, further 30 μm or less, and depending on the material, it is 20 μm or less.

  As the material constituting the base sheet, in addition to the materials listed as the plastic film to be perforated, there are water-resistant and perforated materials, but the base sheet is only a secondary material. Therefore, an inexpensive and easy-to-handle material is practical, and among them, a polyester-based resin film can be suitably used from the viewpoint of price and handling. The thickness of the laminated film is 1.2 N /% (elongation) or more per 15 mm width, preferably 1.5 N /% per 15 mm width by laminating via a water-soluble adhesive. (Elongation) The thing of the grade which can be reinforced more than is mentioned. In terms of thickness, the thickness is usually 30 μm or more, preferably 50 μm or more from the viewpoint of inexpensiveness and ease of handling. The upper limit of the thickness is not particularly limited as long as it has perforation properties, but from the viewpoint of cost and the like, it is usually 500 μm or less, and practically 100 μm or less, and the diameter of the hole to be perforated. From the standpoint of balance, the diameter is preferably twice or less the diameter of the hole.

The adhesive used for laminating the base sheet on the plastic film to be perforated is an adhesive that does not peel between the plastic film to be perforated and the base sheet when performing a perforating process in a later step. For example, the peel strength in the dry state between the plastic film layer to be perforated and the base sheet layer is 0.01 N / cm or more, preferably 0.02 N / cm or more, and The perforated film and the base sheet can be easily separated by wetting the adhesive layer with an aqueous solvent, that is, the perforated film and the base sheet can be easily peeled by a stress that does not cause wrinkles in the perforating process. A material that can obtain a degree of solubility, that is, an easily water-soluble adhesive is preferably used.

In particular, the peel strength in the dry state is the peel strength when measured while always maintaining the adhesive layer at the peel interface between the plastic film layer to be perforated of the laminated film and the base sheet layer in a dipped state. Substantially 0.3 N / cm or less, preferably 0.2 N / cm or less, more preferably 0.15 N / cm or less. As the above-mentioned easily water-soluble adhesive, specifically, a plastic film to be perforated and a material selected from the materials constituting the base sheet are appropriately selected from known adhesives. As specific examples of commercially available water-soluble adhesives, water-soluble urethane resin-based "Paramillion AF-36" and "Paramillion FL-34" (both trade names, manufactured by Ohara Palladium Co., Ltd.) are preferably used. Although it can mention, it is not limited to these.

The aqueous solvent includes all solvents that are normally recognized as aqueous solvents in addition to water. For example, a water-soluble organic solvent such as methanol, ethanol, propanol, or glycols is added to 100 parts by mass of water. The mixed solvent which mix | blended 100 mass parts or less can be mentioned. Moreover, although the temperature of the solvent at the time of immersion is desirably normal temperature, it may be slightly higher than 45 ° C.

The method for forming the laminated film by laminating the plastic film to be perforated and the base sheet can be performed by known means. For example, when a heat-adhesive adhesive such as the above-mentioned Paramillion AF-36 is used as the adhesive, it is usually necessary to prevent excessive stress on the plastic film to be perforated. An adhesive solution is applied to the surfaces to be bonded and dried to obtain a base sheet having an adhesive layer, and a plastic film to be perforated should be bonded to the surface of the adhesive layer of the base sheet having the adhesive layer A method of laminating the surfaces with heat lamination is exemplified. In the above laminating process, it is preferable that the plastic film to be perforated should not be tensioned as much as possible. For example, when continuously manufacturing a long product, a device such as a tension cutter is used together. It is preferable to take this into consideration.

The concentration of the adhesive solution is appropriately set according to the type and characteristics of each adhesive, but is usually 2 to 50% by mass, but in the case of a laminated film with this base sheet of the present invention. The coating amount of the adhesive is usually 0.1 to 5 μm, and practically about 0.2 to 1 μm as the thickness after drying, and may be relatively small. 10% by weight is sufficient. Moreover, although said drying conditions are suitably set by the kind of used adhesive agent, the density | concentration of a solution, and the application quantity, it is about 30 to 180 second normally in a hot air of 80-100 degreeC.

  In the above laminated film, even if the base sheet layer is omitted by increasing the thickness of the adhesive layer, if the perforation processing suitability is excellent, that is, the initial configuration is based on the configuration of only the plastic film to be perforated and the adhesive layer. When the tensile stress is 1.2 N /% (elongation) or more per 15 mm width, the base sheet layer can be omitted. In this case, an adhesive layer is provided on one or both sides of the plastic film to be perforated. In such a configuration, the peeling operation is unnecessary, and the aqueous solvent for the adhesive layer acts on the entire coated surface of the adhesive layer, so that the adhesive cleaning process is simple.

  In the laminated film in which the above base sheet is omitted, the thickness of the adhesive layer is usually 20 to 100 μm, preferably 30 to 80 μm, practically combined with one or both sides of the plastic film in consideration of the degree of the reinforcing effect. Specifically, the thickness is 40 to 60 μm. In this case, the concentration of the adhesive solution used for forming the adhesive layer is usually 20 to 50% by mass and practically 30 to 40% by mass in view of the thick adhesive layer.

The method of laminating the above thick adhesive layer on the surface of the plastic film is usually to first prepare a separate release sheet to avoid excessive stress on the thin plastic film to be perforated. An adhesive solution is applied to the surface and dried to form an adhesive layer on the surface of the release sheet. Next, the surface to be bonded of the plastic film to be perforated is superposed on the surface of the adhesive layer and laminated by heating. After cooling, the above-mentioned release sheet is peeled off. As a result, since the plastic film to be perforated is reinforced with a thick adhesive layer, a large stress is not applied to the plastic film portion to be perforated and no wrinkle is generated. The above adhesive layer can be laminated on both sides of the plastic film to be perforated by repeating the same steps as necessary.

In order to reinforce the plastic film to be perforated by the adhesive layer, even in the case of a laminated film having an adhesive layer provided on one or both sides of the plastic film to be perforated by omitting the base sheet layer In this case, it is preferable that the peel strength (when dried) between the plastic film to be perforated and the adhesive layer is 0.01 N / cm or more. The method for measuring the peel strength is the same as that in the case where a peel opening is formed between the plastic film layer to be perforated and the adhesive layer, and the base film is laminated by grasping the ends of both layers. If the peel strength can be measured, the method may be used. If the method cannot measure the peel strength, for example, an adhesive tape with high adhesive strength (polyester adhesive tape 31B, manufactured by Nitto Denko Corporation) is attached to the surface of the adhesive layer. At the same time, the peel strength can be measured in the same manner as in the case of laminating the base film by grasping both ends of the end of the plastic film to be perforated and the end of the adhesive tape. In this case, if peeling occurs at the interface between the pressure-sensitive adhesive tape and the adhesive, the peel strength between the plastic film to be perforated and the adhesive layer is greater than the above measured value.

  Plastic film layer to be perforated / adhesive layer / base sheet layer, base sheet layer / adhesive layer / plastic film layer to be perforated / adhesive layer / base sheet layer, perforation obtained as described above The laminated film having the configuration of the plastic film layer / adhesive layer to be punched or the adhesive layer / plastic film layer to be punched / adhesive layer has a low initial tensile stress of the plastic film to be punched. In addition, since the tensile stress is reinforced, the laminated film is suitable for the perforating process. By perforating in the state of the laminated film, the perforating process is stabilized and the accuracy of the perforating position is excellent.

  The means for perforating the laminated film is not particularly limited, and known means can be applied. For example, a tip-shaped convex shape corresponding to the target perforated shape and a concave shape corresponding thereto And press-type perforation by a concavo-convex mold arranged in a desired pattern. In particular, a punching device that uses a pair of concave and convex molds and appropriately controls the drilling position from the side of the punching device can be suitably used.

  From the laminated film perforated by the above means, the target perforated film is isolated by removing and / or peeling off the laminated adhesive layer and base material layer. At this time, particularly when the perforations are dense and the area ratio of the perforated portions is large, the remaining non-perforated portions are usually elongated and the area ratio is small. Therefore, it is preferable to handle with care so that the perforated laminated film is not stressed as much as possible.

In the method of removing and / or peeling the adhesive layer and the base sheet layer of the laminated film perforated by the above means, an aqueous solvent is allowed to act on the adhesive layer of the laminated film perforated. Examples of the method include peeling or removing in a state in which the perforated film is not subjected to strong stress by substantially reducing the peel strength by swelling or dissolving. Specific examples of such a method include, for example, a method of forming a peeling opening at the end of a perforated laminated film and then immersing it in a water bath at room temperature, peeling the film while keeping the peeling opening in water, and taking it out of the water bath. I can do it. The speed of taking out from the water bath is appropriately adjusted depending on conditions such as the water solubility of the adhesive used and the degree of perforation. The perforated film thus isolated can be washed by rinsing and rinsing the remaining adhesive, if necessary, in the above-mentioned aqueous solvent bath or its flow, if necessary in a warm bath or its flow. A perforated film having a uniform perforation pitch and no residue of an adhesive or the like can be easily obtained.

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to the following examples.
In the examples and comparative examples, the evaluation methods for various characteristics were based on the following criteria.

(1) Peel strength before drilling (N / cm)
A test piece having a width of 15 mm and a length of 200 mm is taken from the laminate sheet before punching, and a peeling opening is provided between the plastic film to be punched and one of the end parts having a width of 15 mm, and each end thereof. The peel strength when peeled at a peel distance of 100 mm and peel speed of 300 mm / min by the peel angle 180 degree method was used.

(2) Presence / absence of adhesive / adhesive residue on the surface of the perforated film after washing with water The plastic film to be perforated isolated by the above-described peel strength test before perforation is immersed in water filled in a 500 ml beaker for 30 seconds. After that, hold it in warm water of 45 ° C filled in a 500 ml beaker with tweezers, rinse it for 10 seconds, press gauze to wipe off the water, observe the surface with a 100x microscope, and adhesive / adhesive The presence or absence of agent residues was observed.

(3) Peel strength (N / cm) when the adhesive layer / adhesive layer at the peeling interface is wet
A test piece having a width of 15 mm and a length of 200 mm was taken from the laminate sheet before punching, and a peeling opening was provided at the interface between the plastic film layer to be punched and the base sheet layer on one end of the 15 mm width. With each of the peeling ends fixed to both grips of the measuring apparatus, water at room temperature was poured into the pressure-sensitive adhesive layer / adhesive layer at the peeling interface with a dropper, and the peeling distance was 100 mm. The peel strength when peeled at a peel speed of 300 mm / min by the peel angle 90 ° method was used.

(4) Presence or absence of vertical movement of the film during the punching process
A roll-wrapped laminated film with a width of 48 mm as a laminated film for punching, which has a pair of convex and concave rods corresponding to a 0.5 mmφ circular hole, and is intermittently press-pierced in the width and length directions by controlling the drive unit The film was passed through a press-type punching machine, and the presence or absence of vertical movement of the film during the punching process was observed when the laminated film was punched at 36 mm with a 1 mm pitch in the width direction and 1000 mm with a 1 mm pitch in the length direction.

(5) Accuracy of perforation position of perforated film The accuracy of perforation position such as the uniformity of the hole pitch of the perforated film obtained by the perforation process was evaluated.

[Example 1]
The base material is an adhesive solution in which 100 parts by mass of Paramillion AF-36 (easily water-soluble urethane resin system, solid content 35% by mass, manufactured by Ohara Palladium Co., Ltd.) as an adhesive is dissolved in 600 ml of an organic solvent IPA (isopropyl alcohol). It is applied to Lumirror 38S10 (polyester film, manufactured by Toray Industries, Inc.) having a thickness of 38 μm as a sheet so that the thickness after drying is 0.5 μm and dried in hot air at 100 ° C. for 2 minutes to form an adhesive layer An attached base sheet was prepared. A PPS (polyphenylene sulfide) film having a thickness of 12 μm was superposed on the surface of the base material sheet on the adhesive layer side, and laminated using a roll laminator having a roll temperature of 80 ° C. to obtain a laminated film. For the obtained laminated film, based on the evaluation method described above, peel strength before perforation, presence or absence of adhesive residue after washing, peel strength when the peel interface adhesive layer is wet, and vertical movement of the film during the perforation process The accuracy of the punching position, such as the presence or absence and uniformity of the hole pitch of the punched film, was evaluated, and the results are shown in Table 1 together with the type of adhesive and other main factors.

[Comparative Example 1]
As a reinforcing adhesive tape, a commercially available re-peeling adhesive tape CT100 (trade name, for weak adhesive, manufactured by Panac Co., Ltd.), in which an acrylic adhesive is applied to a polyester film, was used in Example 1 for this adhesive tape. A PPS (polyphenylene sulfide) film having the same thickness of 12 μm was superposed and laminated using a roll laminator at room temperature to obtain a laminated film. About the obtained laminated film, based on the above evaluation method, peel strength before perforation, presence / absence of pressure-sensitive adhesive / adhesive residue after washing, peel strength when the pressure-sensitive adhesive layer / adhesive layer at the peeling interface is wet, perforation The accuracy of the punching position, such as the presence or absence of vertical movement of the film during the process and the uniformity of the hole pitch of the punched film, was evaluated, and the results are shown in Table 1 together with the adhesive / adhesive formulation and the main elements of the examples. . In addition, although the perforation treatment was almost carried out, the adhesive residue could not be removed even after washing with water on the back of the perforated film that was isolated by peeling off the base film, and used for precision instruments. As it was not usable.

[Comparative Example 2]
In Comparative Example 1, Comparative Example 1 except that a commercially available re-peeling adhesive tape ST100 (trade name, for weak adhesive, manufactured by Panac Co., Ltd.) in which an acrylic adhesive was applied to a polyester film was used as the reinforcing adhesive tape. In the same manner as above, the peel strength before perforation, the presence or absence of adhesive / adhesive residue after washing with water, the peel strength when the adhesive layer / adhesive layer at the peeling interface is wet, the presence or absence of vertical movement of the film during the perforation process, The accuracy of the perforation position, such as the uniformity of the hole pitch of the perforated film, was evaluated, and the results are listed in Table 1 together with the adhesive formulation and the main elements of the examples. In addition, as in Comparative Example 1, the perforation treatment was almost performed, but the surface of the perforated film that was isolated by peeling off the base film remained unremovable even after washing with water, It could not be used as a perforated film for precision equipment.

[Comparative Example 3]
In Example 1, with the plastic film to be perforated without providing the base sheet layer, based on the above evaluation method, the presence or absence of vertical movement of the film during the perforation process, the uniformity of the hole pitch of the perforated film, etc. The accuracy of the drilling position was evaluated, and the results are shown in Table 1. It should be noted that the perforation process could not be continued because the film was pulled up and down by the upper convex rod during perforation and the film did not move away from the mold.

＊１ 穿孔時にフィルムが上部凸型の棒に引っ張られてフィルムが上下し、型から離れないため穿孔処理を続けることが出来なかった。 Table 1

* 1 During punching, the film was pulled up and down by the upper convex rod, and the film moved up and down.

(Summary of experimental results)
As is clear from the results in Table 1, when the plastic film to be perforated is thin, waviness and vertical movement of the film are easily caused by slight tension, and the perforation process is not stabilized as it is (Comparative Example 3). Even in the case of plastic film that cannot be perforated, the base film is laminated with a water-soluble adhesive during the perforation process and reinforced in the form of a laminated film, so that the film has a stable and correct pitch in the perforation process. In addition, it is possible to perforate at the same time, and after the perforation, it is possible to reduce the peel strength by pouring water into the adhesive layer at the peeling interface, etc., so that the laminated film is not subjected to a large peeling stress that causes the thin perforated film to be wrinkled. The base sheet and adhesive can be easily removed from the substrate by rinsing the surface of the perforated film in a water bath after peeling. Perforation pitch uniform, it was possible to easily obtain a perforated film remaining is not an impurity such as an adhesive.

The laminated film of the present invention can be used even if the plastic film to be perforated is thin or the initial tensile stress is small, even when waviness or wrinkles are easily generated with a slight stress. By reinforcing in the form of a laminated film for fine perforation, for example, the perforation process using a concave and convex mold stabilizes the film in the perforation process, and the perforation process can be performed at the correct pitch. As a result, the perforation pitch is uniform. In addition, it is possible to easily obtain a perforated film having no residual impurities such as an adhesive and an adhesive, and the industrial applicability is great.

Claims (4)

A base sheet is laminated on one or both sides of a plastic film to be perforated having an initial tensile stress of 1.0 N /% or less per 15 mm width via a water-soluble adhesive layer, and the initial tensile stress is 15 mm in width. A laminated film for fine perforation characterized by being 1.2 N /% or more per unit.
2. The laminated film for fine perforation according to claim 1, wherein a peel strength in a dry state between the plastic film layer to be perforated and the base sheet layer is 0.01 N / cm or more.
Peel strength is substantially 0.3 N / cm or less when measured while the adhesive layer at the peeling interface between the plastic film layer to be perforated and the base sheet layer is always kept wet. The laminated film for fine perforations according to claim 1 or 2.
After perforating in the state of the laminated film according to any one of claims 1 to 3, an aqueous solvent is allowed to act on the adhesive layer to dissolve the adhesive layer to isolate the perforated film. A method for producing a finely perforated film.