Method for manufacturing printed plastic film and tubular plastic film

Abstract

To provide a method for producing a printed plastic film that minimizes friction between the film and an ink head, facilitating clear printing, when printing by directly spraying microdroplet ink onto the surface of a cylindrical plastic film.SOLUTION: A method for producing a printed plastic film includes at least a printing step where, with the inner surfaces 1a of a cylindrical plastic film 1 blocked together, ink is applied to the outer surface 1b of the cylindrical plastic film 1 by the inkjet printing technique, thus forming a printed layer.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an inkjet printing method in which it is not necessary to prepare an underplate, such as gravure printing or offset printing, and for example, ink droplets are directly sprayed onto a plastic film for printing. The present invention also provides a tubular plastic film that can be preferably used in the above inkjet printing method.

Background Art

[0002] Conventionally, in printing on plastic films, particularly multi-layer plastic films, gravure printing has been the mainstream. In contrast, inkjet printing, which can achieve high-definition and high-resolution printing, has been adopted in the film industry since around 2007. Different from gravure printing, inkjet printing does not require the preparation of an underplate, and thus has the characteristic of low manufacturing costs. Also, by directly spraying ink droplets atomized by the inkjet method for printing, vivid and beautiful printing is possible. Furthermore, it is possible to print in small lots of various varieties, for example, to provide packages with different patterns for each season.

[0003] In inkjet printing, it is important to keep the distance between the film and the ink head as close as possible for clear printing. In such inkjet printing, conventionally, printing is often performed on flat films. However, when printing on a tubular (tube-shaped) film, the tubular film bulges due to air pockets on the inner surface, etc., and rubbing between the film and the ink head occurs, which may cause printing defects. In conventional gravure printing, since the film is pressed against the plate cylinder for printing, even if there are some air pockets in the film, rubbing with the ink head does not pose a problem. However, in inkjet printing, since the film is conveyed only by guide rolls for continuous printing, when air pockets or the like occur in the film, there is no mechanism to suppress rubbing with the ink head.

[0004] To eliminate friction between the film and the ink head, it is common to increase the distance between the film and the ink head. For example, Patent Document 1 discloses a method for manufacturing printed materials that enables stable ink ejection even when the distance between the film and the ink ejection port of the inkjet head is increased. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2020-62784 [Overview of the Initiative] [Problems that the invention aims to solve]

[0006] However, in the method described in Patent Document 1, the distance from the ink ejection port of the ink head to the film surface is long, which, as mentioned above, makes it easy for the print to become unclear or develop streaks. For this reason, there is a need for a printing method that minimizes friction between the film and the ink head and enables clear printing.

[0007] Therefore, the object of the present invention is to provide a method for manufacturing a plastic film printed material that minimizes friction between the film and the ink head when printing by directly spraying droplet-formed ink onto the surface of a tubular plastic film, and enables clear printing. Furthermore, the object of the present invention is to provide a tubular plastic film suitable for manufacturing the above-mentioned plastic film printed material. [Means for solving the problem]

[0008] As a result of diligent research to achieve the above objective, the inventors of this invention have found that by printing with the inner surfaces of tubular plastic films blocked from each other, friction between the film and the ink head is less likely to occur when printing on the surface of the tubular plastic film using an inkjet printing method, and that clear printing is possible. This invention was completed based on these findings.

[0009] In other words, the present invention provides a method for manufacturing a printed plastic film, comprising a printing step of applying ink to the outer surface of a tubular plastic film by inkjet printing while the inner surfaces of the tubular plastic films are blocked from each other, thereby forming a printed layer.

[0010] In the above-described blocking state, the peel strength between the inner surfaces is preferably 20 to 50 N.

[0011] It is preferable that the inner surfaces of the tubular plastic film are bonded together at both ends in the TD direction.

[0012] It is preferable that the inner surfaces of the above-mentioned tubular plastic film are bonded together in the TD direction.

[0013] In the tubular plastic film described above, it is preferable that the region where the inner surfaces are bonded together extends in the MD direction.

[0014] The above manufacturing method may include a molding step of forming the tubular plastic film by co-extrusion inflation.

[0015] The above manufacturing method may include, after the printing step, an internal peeling step to eliminate the blocking in the tubular plastic film and separate the inner surfaces from each other.

[0016] Furthermore, the present invention relates to a tubular plastic film in which the inner surfaces are blocked from each other, wherein the inner surface layer of the tubular plastic film contains an antiblocking agent, the content ratio of the antiblocking agent in the layer is 0.1 to 1.4% by mass, and the density of the layer is 0.905 to 0.930 g / cm³. 3 The present invention provides a tubular plastic film for inkjet printing. Preferably, the peel strength between the inner surfaces in the blocked state is 20 to 50 N. [Effects of the Invention]

[0017] According to the method for manufacturing a cylindrical plastic printed matter of the present invention, when printing on the surface of a cylindrical plastic film by an inkjet printing method, rubbing between the film and the ink head is unlikely to occur. Further, since rubbing is unlikely to occur and the distance between the film and the ink head can be shortened, clear printing can be performed on the outer surface of the cylindrical plastic film.

Brief Description of Drawings

[0018] [Figure 1] A TD-direction cross-sectional view showing a state where the inner surfaces of a cylindrical plastic film are blocked in a printing process is shown. [Figure 2] A TD-direction cross-sectional view showing a state where the inner surfaces of a cylindrical plastic film are not blocked in a printing process is shown. [Figure 3] A top view of an embodiment of a cylindrical plastic film in a printing process is shown. [Figure 4] A schematic cross-sectional view for explaining a method of measuring the peel strength between inner layers performed in an example is shown. [Figure 5] A schematic cross-sectional view for explaining a method of evaluating an air pocket performed in an example is shown.

Modes for Carrying Out the Invention

[0019] The method for manufacturing a cylindrical plastic film printed matter of the present invention includes at least a printing step of applying ink on the outer surface of the cylindrical plastic film by inkjet printing to form a printing layer in a state where the inner surfaces of the cylindrical plastic film are blocked.

[0020] (Printing step) In the above printing process, the cylindrical plastic film is transported with its inner surfaces blocking each other, and printing is continuously performed on the outer surface of the cylindrical plastic film by inkjet printing while the opening of the cylinder faces the MD direction. Figure 1 shows a cross-sectional view of the cylindrical plastic film in the TD direction with its inner surfaces blocking each other, and the positional relationship between the cylindrical plastic film and the ink head. As shown in Figure 1, the inner surfaces 1a of the cylindrical plastic film 1 are blocked during printing. This makes it difficult for air pockets to form inside the cylindrical plastic film 1, and when printing on the outer surface 1b of the cylindrical plastic film 1, friction is less likely to occur even when the distance to the ink head 2 is short. On the other hand, as shown in Figure 2, when the inner surfaces 1a of the cylindrical plastic film 1 are not blocked each other, air pockets form inside the cylindrical plastic film 1, and friction occurs between the cylindrical plastic film 1 and the ink head 2.

[0021] The peel strength between the inner surfaces in the blocked state described above is preferably 20N or more, and more preferably 30N or more. When the peel strength is 20N or more, the blocking during printing is sufficiently maintained. The peel strength is preferably 50N or less, and more preferably 40N or less, from the viewpoint of being able to easily peel the inner surfaces together when the blocking in the tubular plastic film is resolved and the inner surfaces are separated in the inner surface peeling process described later. The peel strength is the value measured under the conditions of a peeling angle of 180°, room temperature, peeling speed of 300 mm / min, and sample measurement area of ​​50 mm × 100 mm.

[0022] The above-mentioned blocking refers to a state where the inner surfaces are in close contact with each other, yet can be easily separated by interfacial delamination. However, if the adhesion is such that separation occurs simply by contact, without intentional separation, then it is not considered blocking. Specifically, for example, the delamination strength between the inner surfaces is 15N or less. In contrast, "adhesion," as described below, refers to a state where the inner surfaces are bonded together and cannot be easily separated, such as by cohesive failure during delamination. The above-mentioned blocking may be formed during the molding of the tubular plastic film, or it may be formed by pressing with a conveyor roll or the like. Furthermore, the above-mentioned blocking only needs to be formed in a part of the surface; it may be formed over the entire inner surface of the tubular plastic film, or only partially. In particular, it is preferable that 50% or more (preferably 60% or more, more preferably 80% or more, even more preferably 90% or more, and especially preferably 95% or more) of the entire TD direction area is formed when ink is applied from the ink head. When 50% or more is formed, air is less likely to accumulate on the inner surface, further reducing the possibility of friction with the ink head during printing. If the pressure is below 50%, air tends to accumulate inside, increasing the likelihood of it rubbing against the print head during printing.

[0023] The tubular plastic film described above preferably has its inner surfaces bonded together at both ends in the TD direction, and more preferably has its inner surfaces bonded together so as to extend (continuously) in the MD direction at both ends in the TD direction. Since air pockets tend to form inside the tubular plastic at both ends in the TD direction, bonding the inner surfaces at both ends can further suppress the occurrence of such problems at both ends. The bonding can be carried out by known or conventional methods, such as heat sealing and hot melting. Among these, heat sealing is preferred from the viewpoint that only the inner surfaces at both ends can be selectively bonded together. Furthermore, the heat-sealed portion can be the end of a bag obtained by cutting the tubular plastic film.

[0024] The tubular plastic film described above preferably has its inner surfaces bonded together in the TD direction, and more preferably in the center of the TD direction. Furthermore, it is even more preferable that the bond extends (continuously) in the MD direction within the TD direction (especially in the center of the TD direction). Bonding the inner surfaces within the TD direction further suppresses the occurrence of air pockets within the TD direction. The bonding can be carried out by known or conventional methods, such as heat sealing and hot melting. Among these, heat sealing is preferred from the viewpoint of selectively bonding the inner surfaces of the films. The heat-sealed portion can be the end of the bag obtained by cutting the tubular plastic film. The bonded portion within the TD direction may be only one location or two or more locations, and it is preferable that each location extends in the MD direction. The more bonded locations there are, the less likely friction with the ink head is to occur, but the number of bonded locations should be formed according to the resulting bag.

[0025] From the standpoint of production efficiency, it is preferable to have areas where the inner surfaces are bonded together in the TD direction. In tubular plastic films, if there are no bonded areas between the inner surfaces, printing can only be done in one row in the MD direction. However, if there are multiple continuous bonded areas in the MD direction, excluding both ends, and especially if there are two or more bonded areas, multiple rows can be printed at once, increasing production efficiency.

[0026] Figure 3 shows a top view of a tubular plastic film during the printing process. The tubular plastic film 1 is transported in the MD direction so that the opening surface is in the MD direction. In the tubular plastic film 1, both ends 11 and 12 in the TD direction are heat-sealed to extend in the MD direction, forming a heat-sealed portion 14, where the inner surfaces are bonded together. In addition, in the tubular plastic film 1, the central portion 13 in the TD direction has a heat-sealed portion 14 formed to extend in the MD direction, where the inner surfaces are bonded together. In the embodiment shown in Figure 3, the TD direction ends 11 and 12 and the central portion 13 are heat-sealed portions 14, and there is one continuous bonded portion in the MD direction in the TD direction (central portion 13), excluding both ends. Therefore, it is possible to print the same or different designs in two rows: the non-adhesive region 15a between the TD direction end 11 and the central portion 13, and the non-adhesive region 15b between the TD direction end 12 and the central portion 13, resulting in higher production efficiency compared to printing in only one row.

[0027] The shortest distance between the tubular plastic film and the ink head is not particularly limited, but is preferably 2 mm or less, and more preferably less than 2 mm. The smaller the shortest distance, the clearer the printing. Furthermore, since friction with the ink head is less likely to occur according to the manufacturing method of the present invention, printing can be done with a shorter shortest distance than in conventional methods. Other printing conditions such as the transport speed in the printing process are not particularly limited.

[0028] The tubular plastic film to be printed in the above printing process can be any shape that is tubular. Examples include a seamless tubular film that does not have any connecting parts such as film laminations or joints in the circumferential direction of the tubular body, a tubular film in which the ends of multiple flat films are laminated together, and a tubular film in which both ends of a single flat film are laminated together. Among these, a seamless tubular film is preferred. Examples of the above seamless tubular film include a tubular film formed into a tubular shape by a resin melt extrusion method such as the inflation method. Among these, a tubular film formed into a tubular shape by the inflation method (inflation film) is preferred, and furthermore, an inflation film manufactured by a water-cooling method (water-cooled inflation film) is particularly preferred from the viewpoint of the inner surface being easily blocked.

[0029] The tubular plastic film described above may be single-layered or multi-layered. In the case of a single-layered tubular plastic film, the single layer provides the inner and outer surfaces of the tubular plastic film. In the case of a multi-layered tubular plastic film, it is preferable that the tubular plastic film is formed by a co-extrusion method (particularly the co-extrusion inflation method).

[0030] The structure of the tubular plastic film described above is, in principle, independent of the number of layers constituting the multilayer film, the type of resin constituting the layers, and the relative thicknesses of the layers. Preferably, the tubular plastic film has at least three layers, with a sealant layer (inner layer), an intermediate layer, and an outer layer laminated in that order. Preferably, the outer layer contains at least one selected from the group consisting of polyamide (nylon), polyester, polyolefin, and polystyrene. Examples of polyamide include 6-nylon, 66-nylon, 6-66 nylon, 12-nylon, 6-12 nylon, and amorphous nylon. Examples of polyester resin include polyethylene terephthalate and polybutylene terephthalate. Examples of polyolefin include polyethylene and polypropylene.

[0031] The inner layer of the tubular plastic film (the inner layer if the tubular plastic film is multilayered) preferably contains a polyolefin. The polyolefin is preferably polyethylene, and more preferably linear low-density polyethylene (LLDPE). The polyolefin content in the inner layer is preferably 80% by mass or more, more preferably 90% by mass or more, and even more preferably 95% by mass or more. Each of the layers may consist of only one type of resin, or two or more types.

[0032] The density of the layer providing the above-mentioned inner surface is not particularly limited, but is typically between 0.895 and 0.940 g / cm³. 3 Preferably, and more preferably, 0.905 to 0.930 g / cm³ 3 Therefore, if the density of the above layers is within the above range, blocking between inner surfaces is more likely to occur in a moderate manner.

[0033] The layer providing the above-mentioned inner surface preferably contains an antiblocking agent. Including an antiblocking agent makes it easier to separate the inner surfaces from each other after the printing process. One type of antiblocking agent may be used, or two or more types may be used.

[0034] As the antiblocking agent described above, known or conventional antiblocking agents used in films can be used, as long as they do not impair the effects of the present invention. Examples include inorganic particles such as silica, zeolite, talc, smectite, vermiculite, mica, kaolin, and other clay compound particles; organic particles such as acrylic resins like PMMA, polyolefin resins like ultra-high molecular weight PE, polystyrene resins, polyurethane resins, polyester resins, silicone resins, fluororesins, and copolymers of monomers constituting these resins.

[0035] The amount of the antiblocking agent is appropriately adjusted according to the components that make up the layer providing the inner surface. For example, if the layer providing the inner surface is a resin layer, the amount is appropriately adjusted according to the type of resin. The content ratio of the antiblocking agent in the layer providing the inner surface is, for example, 0.1 to 1.4% by mass of the total amount of the layer. If the content ratio is 0.1% by mass or more, the inner surfaces can be separated more easily after the printing process. If the content ratio is 1.4% by mass or less, the blocking can be maintained more sufficiently during the printing process.

[0036] If the layer providing the inner surface of the cylindrical plastic is a resin layer, the resin layer may contain other components besides the resin and antiblocking agent. Examples of these other components include antioxidants, ultraviolet absorbers, light stabilizers, lubricants (slip agents), flame retardants, fillers, and colorants. Including the lubricant can suppress re-blocking after the blocking has been resolved. Each of these other components may be used individually or in combination of two or more.

[0037] The method for blocking the inner surface of the tubular plastic film described above is not limited to the addition of anti-blocking agents or other additives, or the adjustment of their amounts. The degree of blocking is due to various factors, such as the total thickness of the film and the stiffness of the film. In addition, for a tubular film formed by laminating two ends of a single flat film, pressure may be applied to the film at the same time as the ends are laminated to form blocking between the inner surfaces. For tubular films that do not have internal blocking or tubular films with relatively weak blocking, appropriate pressure or heat may be applied to the film as needed to form moderate internal blocking between the inner surfaces.

[0038] The total thickness of the tubular plastic film described above (distance from the outer surface to the inner surface) can be appropriately adjusted according to the mass of the liquid to be filled into the bag, impact resistance, and cost, and is, for example, 20 to 200 μm, preferably 40 to 100 μm.

[0039] The tubular plastic film described above is preferably an unstretched film. In this specification, "unstretched film" refers to a film that has not been intentionally stretched during the manufacturing process, and includes films that have been slightly stretched as a result of roll-to-roll transport or winding (for example, with a stretch ratio of 1.05 or less).

[0040] The above manufacturing method may include other steps besides the printing step. Examples of these other steps include a step of forming a tubular plastic film from a resin composition (molding step), and a step of removing the blocking in the tubular plastic film after the printing step and separating the inner surfaces (inner surface peeling step).

[0041] (molding process) The molding method in the above molding process can be a known or conventional molding method. Among these, the resin melt extrusion method is preferred, the inflation method is more preferred, and the water-cooled inflation method is even more preferred. These methods make it possible to easily produce seamless tubular plastic films in which the inner surfaces are easily blocked.

[0042] When the tubular plastic film is multilayered, it is preferable to form the tubular plastic film by co-extrusion in the molding process. That is, it is preferable to form the tubular plastic film by co-extrusion inflation (particularly co-extrusion water-cooled inflation) in the molding process. The molding conditions such as heating temperature, cooling temperature, and winding speed in the molding process are adjusted as appropriate depending on the structure of the tubular plastic film and are not particularly limited.

[0043] (Internal peeling process) In the above-mentioned internal peeling process, the blocking between the internal surfaces that was maintained in the above-mentioned printing process is eliminated and the internal surfaces are separated from each other. This peeling can be carried out by known or conventional methods, such as blowing air into the inside of a tubular plastic film.

[0044] Furthermore, the process may include steps for partially bonding the inner surfaces of the tubular plastic film that has undergone the printing process, or for cutting it. The bonding and cutting can be performed in the TD direction and the MD direction, respectively, depending on the desired shape. For example, the bottom of the resulting bag can be formed by bonding (e.g., heat sealing) the tubular plastic film that has undergone the printing process in the TD direction and cutting along the bonded portion in the TD direction. Alternatively, the sides of the resulting bag can be formed by bonding the inside of the tubular plastic film in the TD direction along the MD direction and cutting along the bonded portion in the MD direction. In this way, by appropriately combining the bonding process with a cutting process, individual bags that are tubular plastic films with a bottom can be manufactured from the tubular plastic film.

[0045] According to the present invention's method for manufacturing a tubular plastic film, friction between the film and the ink head is less likely to occur when printing on the surface of the tubular plastic film using an inkjet printing method. Furthermore, because friction is less likely to occur and the distance between the film and the ink head can be shortened, clear printing can be achieved on the outer surface of the tubular plastic film. [Examples]

[0046] The present invention will be described in more detail below based on examples, but the present invention is not limited to these examples. Table 1 shows the film layer thickness, the type and density of the inner layer resin, and the amount of antiblocking agent blended.

[0047] The conditions for co-extrusion using the co-extrusion water-cooled inflation method are as follows: <Conditions for the inflation method> • Extrusion equipment: Co-extrusion water-cooled inflation unit Extrusion temperature: 200°C (linear low-density polyethylene), 250°C (nylon 6), 180°C (maleic anhydride-modified polyolefin) ·Cooling water temperature: 10~60℃

[0048] Example 1 Nylon 6 (6NY) was used as the raw material for the outer layer. A maleic anhydride-modified polyolefin resin was used as the raw material for the adhesive layer. As the raw material for the inner layer, a mixture of linear low-density polyethylene and synthetic zeolite (spherical, average particle size: 7 μm) as an antiblocking agent (AB agent) was used. Using the raw materials for each layer prepared as described above, tubular co-extruded films were fabricated by the water-cooled co-extrusion inflation method.

[0049] The above tubular co-extruded film was flattened by crushing, and both ends in the TD direction were heated at 200°C to form an adhesive region with a width of 8 mm. A multilayer co-extruded side seal film of Example 1 was then produced, consisting of a laminated structure of [outer layer 16 μm / adhesive layer 7 μm / inner layer 47 μm] (total thickness 70 μm).

[0050] Example 2 A multilayer co-extruded side seal film of Example 2 was prepared in the same manner as in Example 1, except that the amount of synthetic zeolite in the inner layer was changed as shown in Table 1, with a laminated structure of [outer layer 16 μm / adhesive layer 7 μm / inner layer 47 μm] (total thickness 70 μm).

[0051] Example 3 A multilayer co-extruded side seal film of Example 2 was fabricated in the same manner as in Example 1, except that a continuous adhesive region in the MD direction was formed not only at both ends in the TD direction but also in the central part, and the process was carried out in the same manner as in Example 1. The laminate structure consisted of [outer layer 16 μm / adhesive layer 7 μm / inner layer 47 μm] (total thickness 70 μm).

[0052] Example 4 A multilayer co-extruded tube film of Example 3 was prepared in the same manner as in Example 1, except that the ends in the TD direction were not heated and no adhesive regions were formed. The laminate structure consisted of [outer layer 16 μm / adhesive layer 7 μm / inner layer 47 μm] (total thickness 70 μm).

[0053] Example 5 A dry laminating adhesive was applied to a 15 μm thick biaxially oriented polyamide film (hereinafter referred to as ONY film), dried in an 80°C oven for 1 minute, and the amount of adhesive applied after drying was 3.0 g / m². 2 The material was then laminated with a multilayer co-extruded film consisting of a laminated structure of [outer layer 17 μm / adhesive layer 5 μm / inner layer 28 μm] (total thickness 50 μm) to produce a laminated product. Subsequently, the sides were sealed to form a tube, and a multilayer co-extruded tube film of Example 5 was produced, consisting of a laminated structure of [outer layer 17 μm / adhesive layer 5 μm / inner layer 28 μm / adhesive / ONY film 15 μm] (total thickness 70 μm).

[0054] Comparative Example 1 A multilayer co-extruded side seal film of Comparative Example 1 was prepared in the same manner as in Example 1, except that the amount of synthetic zeolite in the inner layer was changed as shown in Table 1, with a laminated structure of [outer layer 16 μm / adhesive layer 7 μm / inner layer 47 μm] (total thickness 70 μm).

[0055] Comparative Example 2 A multilayer co-extruded tube film of Comparative Example 1 was prepared in the same manner as Comparative Example 1, except that the ends in the TD direction were not heated and no adhesive regions were formed. The laminate structure consisted of [outer layer 16 μm / adhesive layer 7 μm / inner layer 47 μm] (total thickness 70 μm).

[0056] (evaluation) Each film (tubular film) obtained in the examples and comparative examples was evaluated as follows. The results are shown in Table 1.

[0057] (1) Delamination strength between inner layers From each tubular film obtained in the examples and comparative examples, a section was cut so that the area where the inner surfaces were in close contact was 50 × 100 mm, thereby obtaining a measurement sample in which the inner layers of two films were in close contact. As shown in Figure 4, the end of the measurement sample S was peeled off so that the measurement length L was 100 mm, and the resistance force (peel strength) was measured when one film Sa peeled off at one end and the other film Sb peeled off at the other end were simultaneously pulled in a 180° direction (direction of the arrow shown in Figure 4) at a peeling speed of 300 mm / min. As a result, although the peel strength of the comparative example test sample could be measured, it peeled off immediately after the start of the measurement, and it was determined that no blocking had been formed.

[0058] (2) Air pocket Each of the long tubular films obtained in the examples and comparative examples was transported for 500m in the direction indicated by arrow D to a printing press equipped with ink heads 2a-2c and guide rolls 3a-3d, as shown in Figure 5. During this process, the presence or absence of air pockets inside the tubular film 1 was visually checked. Even if air pockets were not observed immediately after transport, they gradually accumulated, so the condition was checked after a certain length of transport. Air pockets are usually easily observed just before the guide roll 3a (indicated by P). The condition was evaluated as follows: ◎ if the air pockets had been eliminated, ○ if there were some air pockets but they did not affect printing, and × if there were air pockets that rubbed against the ink heads.

[0059] [Table 1]

[0060] As shown in Table 1, when the tubular film of the example in which blocking was formed on the inner surface was transported by the printing press, the occurrence of air pockets was suppressed, and it was evaluated that friction against the ink head could be prevented. On the other hand, when the tubular film of the comparative example in which blocking was determined not to be formed on the inner surface was transported by the printing press, air pockets occurred, and friction against the ink head occurred.

[0061] The following describes variations of the invention relating to this disclosure. [Note 1] A method for manufacturing a printed plastic film, comprising a printing step of applying ink to the outer surface of a tubular plastic film by inkjet printing while the inner surfaces of the tubular plastic films are blocked from each other to form a printed layer. [Note 2] The method for manufacturing a plastic film printed material according to Note 1, wherein the peel strength between the inner surfaces in the blocked state is 20 to 50 N. [Note 3] A method for manufacturing a plastic film printed article according to Note 1 or 2, wherein the inner surfaces of the tubular plastic film are bonded together at both ends in the TD direction. [Appendix 4] The method for manufacturing a plastic film printed material according to Appendix 3, wherein the inner surfaces of the tubular plastic film are bonded together inside in the TD direction. [Note 5] The method for manufacturing a plastic film printed article according to Note 3 or 4, wherein the region in the tubular plastic film where the inner surfaces are bonded together extends in the MD direction. [Appendix 6] A method for manufacturing a plastic film printed material according to any one of Appendix 1 to 5, comprising a molding step of forming the tubular plastic film by co-extrusion inflation. [Note 7] A method for manufacturing a plastic film printed article according to any one of Notes 1 to 6, comprising an internal peeling step after the printing step to eliminate the blocking in the tubular plastic film and separate the inner surfaces from each other. [Note 8] It is a tubular plastic film with its inner surfaces blocked together. The layer providing the inner surface of the tubular plastic film contains an antiblocking agent, and the content ratio of the antiblocking agent in the layer is 0.1 to 1.4% by mass. The density of the aforementioned layer is 0.905 to 0.930 g / cm³. 3 This is a tubular plastic film for inkjet printing. [Note 9] The tubular plastic film as described in Note 8, wherein the peel strength between the inner surfaces in the blocked state is 20 to 50 N. [Explanation of symbols]

[0062] 1. Tubular plastic film 1a Inner Self 1b External surface 11,12 TD direction end 13 Center part in TD direction 14 Heat seal section 15a,b Non-adhesive area 2,2a,2b,2c Inkhead 3a,3b,3c,3d guide roll

Claims

1. A method for manufacturing a printed plastic film, comprising a printing step of applying ink to the outer surface of a tubular plastic film by inkjet printing while the inner surfaces of the tubular plastic films are blocked from each other, thereby forming a printed layer.

2. A method for manufacturing a plastic film printed article according to claim 1, wherein the peel strength measured between the inner surfaces in the blocked state under the conditions of a peel angle of 180°, room temperature, peel speed of 300 mm / min, sample measurement area of ​​50 mm × 100 mm, and measurement length L of 100 mm is 20 to 50 N.

3. A method for manufacturing a plastic film printed article according to claim 1 or 2, wherein the inner surfaces of the tubular plastic film are bonded together at both ends in the TD direction.

4. The method for manufacturing a plastic film printed article according to claim 3, wherein the inner surfaces of the tubular plastic film are bonded together inside in the TD direction.

5. The method for manufacturing a plastic film printed article according to claim 3, wherein the region in the tubular plastic film where the inner surfaces are bonded together extends in the MD direction.

6. A method for manufacturing a plastic film printed article according to claim 1 or 2, comprising a molding step of forming the tubular plastic film by a co-extrusion inflation method.

7. A method for manufacturing a printed plastic film according to claim 1 or 2, further comprising an internal peeling step after the printing step, which removes the blocking in the tubular plastic film and separates the inner surfaces from each other.

8. It is a tubular plastic film with its inner surfaces blocked together. The layer providing the inner surface of the tubular plastic film contains an antiblocking agent, and the content of the antiblocking agent in the layer is 0.1 to 1.4% by mass. The density of the aforementioned layer is 0.905 to 0.930 g / cm³. ３ This is a tubular plastic film for inkjet printing.

9. The tubular plastic film according to claim 8, wherein the peel strength measured between the inner surfaces in the blocked state is 20 to 50 N under the conditions of a peel angle of 180°, room temperature, peel speed of 300 mm / min, sample measurement area of ​​50 mm × 100 mm, and measurement length L of 100 mm.

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