JP2019209580A - Flexographic printing machine, method for manufacturing printing film with use of the printing machine, and printing film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a printing machine capable of high-quality printing for a long period of time even on a film base material which has not been subjected to corona discharge treatment. SOLUTION: In a center drum type flexo printing machine 1 provided with a center drum 2 along which a film substrate is provided, and a plurality of printing units 20 and 30 installed around the center drum 2, a plurality of printing operations are performed. Of the units 20 and 30, one or a plurality of printing units 20 located on the upstream side has a rubber plate, and the printing unit 30 located on the downstream side of the one or a plurality of printing units 20 has a resin plate. Since the printing unit 20 located on the upstream side includes the rubber plate, even the anchor coating agent containing the solvent for swelling the resin plate can be applied to the film base material by the printing unit 20. [Selection diagram] Figure 1

Description

  The present invention relates to a flexographic printing machine, a printing film manufacturing method using the printing machine, and a printing film.

  Products such as cup noodles, lactic acid bacteria beverages, and dry batteries are usually provided and sold in a state of being packaged with a plastic film or the like. There are various forms of such packaging, and examples of the form of automatic packaging on a production line include shrink packaging (heat shrink packaging).

  Shrink wrapping (heat shrink wrapping) can be packaged with various merits (for example, packaging with the film in close contact with the packaged article, regardless of the shape of the packaged article, etc., even with multiple articles fixed and held together Etc.), the adoption of various articles to be packaged is progressing. In order to improve the appearance and the advertising effect, various designs and letters are printed on the heat-shrinkable film itself to be packaged.

As a material for the heat-shrinkable film, a polyolefin-based resin that is easily heat-sealed and heat-shrinkable is usually employed. Among them, a polypropylene-based resin that exhibits high gloss when formed into a film is preferably employed.
However, when the surface (printing surface) of the heat-shrinkable film is a polyolefin-based resin, particularly a polypropylene-based resin layer, there is a problem that ink fixability is lowered. Therefore, when printing on the polyolefin-based resin layer, a method is adopted in which the film is previously subjected to corona discharge treatment to improve the wettability of the polyolefin-based resin layer.

The corona discharge treatment improves the printability of the film, but has a problem of reducing the heat sealing property. At the time of shrink wrapping, the heat-shrinkable film is cut into an appropriate size so as to cover the packaged article, and the edges are heat-sealed.
When the printing surface and the surface to be heat-sealed are different (in the case of so-called front printing), the heat-sealed surface is not subjected to corona discharge treatment, so that the strength of the heat-sealed portion is maintained. However, since printing is located on the outermost surface of the shrink package, the print may be peeled off or damaged when the package is transported. When the printed surface and the surface to be heat-sealed are the same (in the case of so-called back printing), printing is not located on the outermost surface of the shrink package, and there is a low risk that the printing will peel off or be damaged. However, the surface to be heat sealed is subjected to corona discharge treatment, and the strength of the heat sealed portion is weakened. In addition, there is a problem that the heat seal portion opens immediately after packaging or in a shrinking tunnel thereafter.
In order to solve such a problem, it was also considered to perform a corona discharge treatment except for a portion to be heat-sealed in a subsequent process. However, in the corona discharge treatment, it is possible to set a portion not to be processed in parallel with the film flow direction because of its structural characteristics, but accurately set an unprocessed portion in parallel with the film width direction. I couldn't.

Conventionally, in order to solve the above problems, an anchor coat agent (polyolefin-based resin dissolved in a solvent) is intermittently applied to the printing surface of the film base, except for a portion to be heat-sealed in a subsequent process. There has been proposed a printing method in which an anchor coat layer is provided and an ink layer is formed on the anchor coat layer (for example, Patent Document 1).
In Patent Document 1, a gravure printing machine is used to form an anchor coat layer containing a chlorinated polyolefin resin on a heat-shrinkable polyolefin film, and a design print layer containing a urethane resin is formed on the anchor coat layer. A forming technique is disclosed.

Japanese Patent Laid-Open No. 2014-141403

  Incidentally, flexographic printing and gravure printing are generally employed for film printing. Because flexo printing uses a resin-made resin plate, it is good at printing fine characters and sharp expressions, and the printing machine that uses a center drum has better registration accuracy and printing speed than gravure printing. . On the other hand, gravure printing can clearly print shades, and is good at printing shadows, textures, gradations, and other expressions. Since a metal metal plate is used, the durability of the plate is superior to flexographic printing using a resin resin plate.

The technology of Patent Document 1 has problems such as difficulty in reproducing fine characters and sharp expressions compared to flexographic printing, and uses a large amount of ink compared to flexographic printing, so the amount of solvent used is also large. Therefore, there is a problem that it becomes difficult to comply with environmental regulations.
The anchor coat layer disclosed in Patent Document 1 is formed of a coating liquid in which a chlorinated polyolefin resin is dissolved in an organic solvent such as toluene. Since the resin plate of a flexographic printing machine is easily swelled by an organic solvent such as toluene, when the coating liquid described in Patent Document 1 is applied to a film substrate with a flexographic printing machine, the resin plate immediately swells to a desired level. It becomes impossible to apply an amount of the coating liquid.

  Also, since the anchor coating agent is transparent, the applied position cannot be detected by a sensor or the like and the deviation of the applied position cannot be corrected. Therefore, with the technique disclosed in Patent Document 1, it is difficult to accurately register (position) the anchor coat layer and the design print layer. A thin heat-shrinkable film may cause a slight elongation between the printing units, and is particularly difficult to register.

  In view of the above circumstances, an object of the present invention is to provide a printing machine that can perform high-quality printing over a long period of time even on a film substrate that has not been subjected to corona discharge treatment. Moreover, it aims at provision of the manufacturing method of the printing film using this printing machine. Furthermore, it is an object of the present invention to provide a printing film on which high quality printing has been performed and which has a good heat sealing property.

(Flexo printing machine)
A flexographic printing machine according to a first aspect of the present invention is a center drum type flexographic printing machine comprising: a center drum for aligning a film base; and a plurality of printing units installed around the center drum. Among the printing units, one or a plurality of printing units positioned on the upstream side includes a rubber plate, and a printing unit positioned on the downstream side of the one or a plurality of printing units includes a resin plate.
(Printing film manufacturing method)
The manufacturing method of the printing film of 2nd invention is a manufacturing method of the printing film using the flexographic printing machine of 1st invention, Comprising: On one surface of a film base material, using the printing unit provided with the said rubber plate, An anchor coating agent coating step for applying an anchor coating agent, and an ink coating for applying ink on the anchor coating layer formed by the anchor coating agent coating step using a printing unit including the resin plate. And a construction process in order.
The method for producing a printed film of the third invention is characterized in that, in the second invention, the film substrate is not subjected to corona discharge treatment.
In the second invention or the third invention, the method for producing a printed film according to a fourth invention is the film substrate, wherein the one surface is formed of a polyolefin layer containing a polyolefin resin, and the anchor coating agent is It contains a polyolefin resin and a solvent for dissolving the polyolefin resin.
The method for producing a printed film according to a fifth aspect of the present invention is characterized in that, in the fourth aspect, the solvent contains an ester solvent and / or an ether solvent as a main component.
The method for producing a printed film according to a sixth aspect of the present invention is the method according to the fourth or fifth aspect, wherein the polyolefin resin contained in the anchor coating agent is a chlorinated polyolefin having a chlorination degree lower than 35%, The molecular weight is 30,000 or more and 200,000 or less.
(Print film)
In the printed film of the seventh invention, a printed layer composed of an anchor coat layer and an ink layer is intermittently formed on the polyolefin layer of a film base provided with a polyolefin layer containing a polyolefin-based resin on at least one surface. In the printed film, the anchor coat layer is a chlorinated polyolefin having a chlorination degree lower than 35%, and has a weight average molecular weight of 30,000 to 200,000.
The print film of an eighth invention is characterized in that, in the seventh invention, the film substrate has a thickness of 5 μm to 150 μm.
In the seventh invention or the eighth invention, the printed film of the ninth invention is characterized in that the film substrate is a heat-shrinkable film.

(Flexo printing machine)
According to the first invention, since the printing unit located on the upstream side includes the rubber plate, even the anchor coating agent containing a solvent that swells the resin plate can be applied to the film substrate by the printing unit. it can. Further, since the printing unit located on the downstream side is provided with a resin plate, fine characters and sharp expressions can be printed by applying ink with the printing unit. Further, by adopting the center drum system, the elongation of the film base material is suppressed, and even a transparent anchor coating agent can be applied without causing a positional shift.
(Printing film manufacturing method)
According to the second aspect of the invention, a printed film having an anchor coat layer between the film base and the ink layer can be produced, so that the ink can be appropriately fixed on the film base. In addition, since the anchor coating agent is applied with a rubber plate, the swelling of the plate is suppressed, and printing can be performed continuously for a long period of time.
According to the third invention, since the film substrate is not subjected to corona discharge treatment, the resulting printed film has good heat sealability, and when the packaged article is packaged, the heat seal portion is difficult to open (peeling off). hard).
According to the 4th invention, since the layer by which the anchor coating agent of a film base material is coated and the anchor coating agent both contain polyolefin resin, the anchor coating agent can be appropriately fixed to the film base material. it can.
According to the fifth invention, since the solvent contained in the anchor coating agent is mainly composed of an ester solvent and / or an ether solvent, it is possible to reduce the burden on the worker and the environmental burden.
According to the sixth invention, since the polyolefin resin contained in the anchor coat agent has predetermined physical properties, the polyolefin resin is appropriately dissolved in the ester solvent and / or the ether solvent, particularly the ester solvent. And the ink can be firmly fixed on the film substrate.
(Print film)
According to the seventh invention, on one surface of the film substrate, since the printing layer consisting of the anchor coat layer and the ink layer is intermittently formed, using the portion where the printing layer is not provided, The printed film can be heat sealed well. Further, since the anchor coat layer has predetermined physical properties, the ink can be reliably fixed to the film substrate.
According to the eighth aspect of the invention, it is possible to appropriately form a printed layer regardless of whether the film base is thin or thick.
According to the ninth aspect of the invention, it is possible to perform shrink wrapping that is excellent in design and heat sealability.

It is a schematic explanatory drawing of the printing film F of this embodiment. (A) is schematic explanatory drawing of the flexographic printing machine 1 of this embodiment provided with the printing units 20 and 30, (B) is the rubber | gum arrange | positioned around the center drum 2 of the flexographic printing machine 1 of this embodiment. 2 is a schematic explanatory diagram of a plate printing unit 20. FIG.

  The flexographic printing machine of this embodiment is a facility that prints a pattern or the like on one surface of a film substrate, and even if the surface is a polyolefin layer, the pattern or the like is appropriately printed without being subjected to corona discharge treatment. be able to.

  First, before describing the specific structure of the flexographic printing machine 1 of the present embodiment, the printing film F manufactured using the flexographic printing machine 1 will be described.

<Print film F>
FIG. 1 shows a schematic cross-sectional view of a printing film F manufactured using the flexographic printing machine 1 of the present embodiment.
As shown in FIG. 1, the printing film F has a film base f and a printing layer PL printed on the printing surface fs of the film base f.

(Film base material f)
The film substrate f of the printing film F is a sheet-like film member, and one surface fs (hereinafter, this surface is referred to as a printing surface fs) of the film substrate f is formed of a polyolefin layer POL.

The polyolefin layer POL of the film substrate f is not particularly limited as long as it is a layer containing a polyolefin resin.
Examples of the polyolefin resin include polyethylene resins such as ethylene homopolymers, ethylene and α-olefin copolymers, propylene homopolymers, random copolymers of propylene and ethylene, and propylene and ethylene. Examples thereof include polypropylene resins such as block copolymers, terpolymers of propylene, ethylene and butene, and modified polyolefin resins obtained by modifying these polymers.
The polyolefin layer POL may contain other resins as long as it contains a polyolefin-based resin. For example, examples of other resins include polybutene resins and polyolefin elastomers.

  In addition, when the printing film F is used as a heat-shrinkable film, it is desirable that the polyolefin layer POL contains a polypropylene resin as a main component from the viewpoint of shrinkage characteristics and glossiness of the film.

The film substrate f is not particularly limited as long as it has the polyolefin layer POL as described above.
The film substrate f may be a single-layer film, for example, as shown in FIG. 1, may have a structure in which a base B and a polyolefin layer POL are laminated, and includes another resin layer between the base B and the polyolefin layer POL. The structure may be sufficient, and also the structure by which the other resin layer was laminated | stacked on the surface on the opposite side to the polyolefin layer POL of the base B may be sufficient.

The material of the base B of the film base material f is not particularly limited.
For example, the same material as the polyolefin layer POL may be used, a polyolefin resin different from the polyolefin layer POL may be included, or a resin other than the polyolefin resin may be used as the material. Examples of resins other than polyolefin resins include polyamide resins and polyester resins.

Moreover, as the film base material f, the thing of various uses can be used.
For example, a heat-shrinkable film used for shrink packaging, a wrap film for food packaging, a film for decorating building materials, a stretched film used for lamination, and the like can be used as the film substrate.

The thickness of the film substrate f is not particularly limited.
When the flexographic printing machine 1 of the present embodiment is employed, good printing can be performed from a thin film of about 5 μm to a thick film of about 150 μm. When using the printing film F obtained by the flexographic printing machine 1 of this embodiment as a heat-shrinkable film, the thickness of the film substrate f is preferably 5 μm to 90 μm, particularly 8 μm to 15 μm.

  In the flexographic printing machine 1 of the present embodiment, the film base material f is printed and conveyed in a state along the center drum, and therefore the film base material f is difficult to extend between the printing units. Therefore, even if it is a thin film whose film base material f is less than 10 micrometers, it can print suitably.

  Moreover, as for the film base material f used for the flexographic printing machine 1 of this embodiment, it is desirable that the corona discharge process is not performed. When the corona discharge treatment is performed, it is difficult to heat seal the printing film F when packaging the packaged article.

(Print layer PL)
The printing layer PL of the printing film F includes an anchor coat (hereinafter abbreviated as “AC”) layer ACL and an ink layer IcL laminated on the printing surface fs of the film base material f. The AC layer ACL functions as a layer for fixing the ink layer IcL to the film base material f.

In the printing film F of the present embodiment, the AC layer ACL contains a polyolefin resin.
Examples of the polyolefin resin include chlorinated polyethylene resin, acrylic modified polyethylene resin, polypropylene resin, chlorinated polypropylene resin, and acrylic modified polypropylene resin. Among them, chlorinated polyolefin resins such as chlorinated polyethylene resins and chlorinated polypropylene resins are excellent in the function of fixing the ink layer IcL to the film base f, and are AC agents used for forming the AC layer ACL described later. The solubility in the ester solvent and / or ether solvent which is a solvent is also good.

  When the polyolefin layer POL of the film substrate f is mainly composed of a polypropylene resin, the AC layer ACL preferably includes a chlorinated polypropylene resin and an acrylic modified polypropylene resin, and particularly includes a chlorinated polypropylene resin. Is desirable.

The chlorine content in the chlorinated polyolefin resin is not particularly limited as long as it can be dissolved in a solvent having a reduced influence on the environment, such as an ester solvent and / or an ether solvent.
However, the degree of chlorination is preferably 35% or less, more preferably 20% to 35%. When the degree of chlorination is lower than 20%, it is easy to adhere to the film substrate f, but it is difficult to dissolve in a solvent. On the other hand, if the degree of chlorination is higher than 35%, it becomes easy to dissolve in a solvent, but it becomes difficult to adhere to the film substrate f.
Therefore, from the viewpoints of solubility in a solvent and adhesion to the film base f, the chlorination degree of the polyolefin resin contained in the AC layer ACL is preferably 35% or less, more preferably 20% to 35%. is there. Particularly, from the viewpoint of environment and workability, the chlorination degree of the polyolefin resin is adjusted to 30% or less, preferably 25% to 30%.
In this case, it is desirable that the solvent for the AC agent used for forming the AC layer is mainly composed of an ester solvent. The ester solvent may be a chlorinated polyolefin resin having a low chlorine content, but can be appropriately dissolved and maintain the adhesion to the film substrate f. When using an ether solvent, it is desirable to use it mixed with an ester solvent.

The weight average molecular weight of the polyolefin resin contained in the AC layer ACL is not particularly limited as long as it can be dissolved in the solvent of the AC agent described later.
For example, the weight average molecular weight of the polyolefin resin is preferably 30,000 to 200,000, more preferably 30,000 to 150,000. When the weight average molecular weight is lower than 30,000, the cohesive force is lowered, so that the adhesive force is lowered. On the other hand, when the weight average molecular weight is larger than 200,000, the compatibility is lowered, so that the solubility in a solvent is lowered.
Therefore, from the viewpoints of adhesive strength and solubility, the polyolefin resin contained in the AC layer is preferably adjusted to have a weight average molecular weight of 30,000 to 200,000, more preferably 30,000 to 150,000.

  In particular, from the viewpoint of environment and workability, the polyolefin resin is adjusted so that the weight average molecular weight is 30,000 to 200,000, more preferably 30,000 to 150,000. In this case, even if the solvent of the AC agent described later is a solvent having reduced environmental influences such as an ester solvent and / or an ether solvent, the above-mentioned polyolefin resin is appropriately dissolved and the film base material is dissolved. Can be glued.

  The ink layer IcL of the printing layer PL is a layer constituting a product name of a packaged object such as cup noodles, lactic acid bacteria beverages, dry batteries, beverage bottles, foods, pictures of products, images and the like.

The ink layer IcL can be formed by printing one color or a plurality of colors of ink containing a binder resin, a colorant, and the like. Examples of the binder resin include nitrified cotton, polyamide resin, and polyurethane resin.
Examples of the colorant include known pigments and dyes.
Furthermore, the ink used for forming the ink layer IcL can employ a water-soluble solvent (for example, isopropyl alcohol, ethyl alcohol) or the like as a solvent.

The thickness of the printing layer PL is not particularly limited.
For example, the printing layer PL can be formed to have a thickness of 1 μm to 20 μm. The thickness of the AC layer ACL and the ink layer IcL of the printing layer PL is not particularly limited, but the thickness of the AC layer ACL is 0.5 μm to 5 μm, and the thickness of the ink layer IcL is 0.5 μm to 5 μm per color. Can be formed. For example, when the thickness of the AC layer ACL is 1 μm and the ink layer IcL is two-color printing with a thickness of 1 μm, the printed layer PL with a thickness of 3 μm can be formed.

  The printing film F of this embodiment is provided with a printing layer intermittently. That is, the print film F includes a portion where neither the AC layer ACL nor the ink layer IcL is laminated. Since the polyolefin layer POL appears on the surface of the portion, good sealing strength can be obtained by heat sealing at the portion.

  Moreover, although the shape of the AC layer ACL and the ink layer IcL is the same in the printed film F of FIG. 1, these sizes may be different. If the ink layer IcL is not in contact with the film base material f and the AC layer ACL is interposed between them, for example, there may be a portion where only the AC layer ACL is laminated on the film base material f. For example, the AC layer ACL may be solid-printed except for a portion to be heat-sealed in a subsequent process, and the ink layer IcL may be printed according to the design.

<Flexographic printing machine 1>
Next, the flexographic printing machine 1 of this embodiment will be specifically described.
FIG. 2A shows an outline of a flexographic printing machine 1 (hereinafter simply referred to as a flexographic printing machine 1) of the present embodiment. The flexographic printing machine 1 is a center drum type facility, and includes a center drum 2 and a printing unit 10.

As shown in FIG. 2 (A), the center drum 2 of the flexographic printing machine 1 is a cylindrical roll, and if the supplied film base material f is rotated, the film base material f is rotated. It can be transported to the opposite side to the supplied side.
In FIG. 2A, the center drum 2 rotates counterclockwise around the rotation axis.

In the vicinity of the center drum 2, a film base material supply roller and a film discharge roller are provided.
Specifically, in order to supply the film base material f along the surface of the center drum 2, a film base material supply roller (a roller positioned second from the top of the paper surface in FIG. 2A) is provided. Yes. On the other hand, a film discharge roller (a roller located at the top of the paper surface in FIG. 2A) is provided downstream of the position where the print film F on which the print layer PL is formed is discharged from the center drum 2. Such a roller supports and conveys the printing film F from the non-printed surface.

The flexographic printing machine 1 includes a printing unit 10 that applies an AC agent or ink to a printing surface fs of a film base material f on a center drum 2.
The printing unit 10 includes a printing unit (hereinafter abbreviated as “rubber plate printing unit”) 20 including a rubber plate disposed along the circumferential direction of the center drum 2 and a printing unit (hereinafter referred to as “resin”) including a resin plate. Plate printing unit ”) 30).
In the flexographic printing machine 1 of the present embodiment, the rubber plate printing unit 20 is located at an upstream location where the film base material f is supplied, and the resin plate printing unit 30 is disposed downstream of the rubber plate printing unit 20. Is done.
Even if this rubber plate printing unit 20 is an AC agent using an ester solvent and / or an ether solvent, it can be applied over a long period of time. The resin plate printing unit 30 can form high-quality printing on the AC layer ACL.

The number of the printing unit 10 is not particularly limited as long as it has one or more rubber plate printing units 20 on the upstream side and one or more resin plate printing units 30 on the downstream side.
For example, as shown in FIG. 2A, the printing unit 10 includes one unit of the rubber plate printing unit 20 and three units of the resin plate printing unit 30 (resin plate printing units 30A, 30B, and 30C). can do. The printing unit 10 may be configured to include two units of the rubber plate printing unit 20 and three units of the resin plate printing unit 30 (resin plate printing units 30A, 30B, and 30C). In this case, the rubber plate printing unit 20 may be continuously arranged on the upstream side to which the film base material f is supplied, and then the resin plate printing units 30A, 30B, and 30C may be arranged.

  There is no structural difference between the rubber plate printing unit 20 and the resin plate printing unit 30 except that the printing plate is made of rubber and resin. Therefore, in the following, the rubber plate printing unit 20 will be referred to as the printing unit 20, This will be described as 30 representatives.

  As shown in FIG. 2B, the rubber plate printing unit 20 includes a printing unit 21 that applies a coating liquid to the printing surface fs of the film base f, and a supply unit 25 that supplies the coating liquid to the printing unit 21. And.

  As shown in FIG. 2, the printing unit 21 of the rubber plate printing unit 20 includes a cylindrical roller 23 and a sheet-like printing plate 22 that is wound around and fixed around the roller 23. The printing unit 21 rotates in the opposite direction to the center drum 2. For example, when the center drum 2 rotates counterclockwise, the printing unit 21 is arranged to rotate clockwise.

  The printing plate 22 of the printing unit 21 is a rubber plate whose surface is made of rubber. The rubber plate includes those in which the entire plate is made of rubber, and those in which the surface is made of rubber and the other base layer is made of resin. The printing plate 22 is preferably made of rubber as a whole from the viewpoint of improving durability against organic solvents.

As the material of the rubber used for the printing plate 22, those used for conventional rubber plates can be used without any particular limitation.
Examples of such rubbers include chloroprene rubber, ethylene propyl rubber, chlorosulfonated polyethylene rubber, styrene butadiene rubber, silicon rubber, fluorine rubber, nitrile butadiene rubber, and butyl rubber.

  The printing plate 22 preferably has a structure that can be detachably fixed to the roller 23. In this case, the printing plate 22 can be replaced according to the application.

  As shown in FIG. 2, the supply unit 25 of the rubber plate printing unit 20 includes a supply roll that supplies the coating liquid to the printing plate 22 of the printing unit 21, and a chamber that supplies the coating liquid to the supply roll. Prepare.

The supply roll of the supply unit 25 rotates in the direction opposite to the printing plate 22 of the printing unit 21. For example, the supply roll is a member having the same function as an anilox roll used in a known flexographic printing facility. If the supply roll is provided so as to be detachable, the image quality can be easily adjusted.
The chamber of the supply unit 25 has a structure capable of supplying the retained coating liquid to the supply roll while retaining the coating liquid inside.

  The printing unit 21 of the rubber plate printing unit 20 corresponds to the printing unit of the resin plate printing unit 30. Further, the printing plate 22, the roller 23, and the supply unit 25 of the rubber plate printing unit 20 correspond to the printing plate, the roller, and the supply unit of the resin printing unit 30, respectively, and the supply roll and the chamber of the supply unit 25 are supplied by each. It corresponds to the supply roll and chamber of the part.

  The coating liquid contains the AC agent when used in the rubber plate printing unit 20, and the ink when used in the resin plate printing unit 30.

The printing plate 22 in the rubber plate printing unit 20 is made of rubber as described above. In the resin plate printing unit 30, the surface material of the printing plate is resin.
The resin used for the printing plate in the resin plate printing unit 30 is desirably a photosensitive resin in consideration of ease of plate production, printing accuracy, and the like. Among these, a photosensitive resin composed of a mixture of a prepolymer, an acrylate oligomer, an acrylate monomer, and a photopolymerization inhibitor, a photopolymerization initiator, and the like having an acrylate main skeleton such as urethane, polyester, and polybutadiene is preferable. Used.

<Method for producing printing film F>
Since the flexographic printing machine 1 of the present embodiment has the above-described configuration, the film F described above can be manufactured by the following method by using the flexographic printing machine 1.
The manufacturing method of the printing film F of this embodiment includes an anchor coating agent coating process in which an anchor coating agent is applied to one surface of a film substrate f using a printing unit 20 including a rubber plate, and the anchor coating An ink coating step of coating ink using a printing unit 30 having a resin plate on an anchor coat layer formed by an agent coating step is provided.

  Prior to printing, the film substrate f is first supplied from the film substrate supply roller side of the flexographic printing machine 1 to the surface of the center drum 2, further discharged from the discharge roller side, and installed on the surface of the center drum 2. In addition, the printing film F discharged | emitted from the film discharge roller is wound up by the winding part which is not shown in figure.

  Next, when the center drum 2 of the flexographic printing machine 1 is operated, the film substrate f supplied from the film substrate supply roller side is guided to the discharge roller side by the rotation of the drum 2. At that time, the film base f passes between the printing plates of the printing units 20 and 30 and the center drum 2, and the AC agent and ink are printed on the printing surface fs.

  As shown in FIG. 2A, in the flexographic printing machine 1, a rubber plate printing unit 20, a resin plate printing unit 30A, a resin plate printing unit 30B, and a resin plate printing unit 30C are arranged in this order from the film substrate supply roller side. In the case where it is provided, the AC agent is first applied to the printing surface fs of the film base material f by the rubber plate printing unit 20 to form the AC layer ACL (AC agent application step). Next, ink is applied and printed on the AC layer ACL by the resin plate printing units 30A, 30B, and 30C to form the ink layer IcL (ink coating process).

  Since the flexographic printing machine 1 of the present embodiment employs the center drum system as described above, the ink layer IcL can be printed on the AC layer ACL so as not to deviate from each other (see FIG. 1). . That is, if the flexographic printing machine 1 is used, the printing film F with improved registration accuracy can be manufactured. For this reason, the printing film F excellent in quality can be produced efficiently.

  Here, as the solvent for the AC agent, an organic solvent capable of dissolving the polyolefin-based resin as described above is used.

  In general flexographic printing, since the printing plate is made of resin, printing the AC agent used in the flexographic printing machine 1 of the present embodiment causes problems such as swelling of the printing plate due to the solvent contained in the AC agent. . If printing is performed using a printing plate in which such a problem has occurred, the coating property of the AC agent is deteriorated, and problems such as the coating amount being unstable and printing in a desired shape are likely to occur. And since such swelling advances by use of several times-dozens of times, the problem that a printing plate must be replaced | exchanged in a short space | interval arises.

However, in the printing film manufacturing method of this embodiment, since the AC agent is applied using the rubber plate printing unit 20, the above-described problems can be solved.
The AC agent can be applied without exchanging the printing plate 22 for a period equivalent to flexographic printing when using a conventional water-soluble ink. Therefore, workability is greatly improved.

In particular, when an ester solvent and / or an ether solvent are employed as the solvent for the AC agent, it is possible to reduce the burden on the worker and the environmental burden during the manufacture as compared with a solvent such as toluene.
Moreover, since the swelling of the printing plate 22 of the rubber plate printing unit 20 can be suppressed more appropriately, the use period of the printing plate 22 can be extended and the production efficiency can be increased.

  When an ester solvent and / or an ether solvent are used as the solvent for the AC agent, the above-mentioned physical properties (chlorination degree, weight average molecular weight) are used as the polyolefin resin contained in the AC agent. Thus, the ink can be dissolved more appropriately, and the ink can be firmly fixed by the film base material f.

<Swelling test>
Resin plates A to D and rubber plates A and B made of a photosensitive resin were immersed in normal propyl acetate. After 1 hour, 4 hours, and 24 hours after immersion, the weight change of each plate was confirmed. Table 1 shows the rate of weight increase.

  The solvent to be immersed was changed to methylcyclohexane, and the same test was performed. The results are shown in Table 2. Moreover, the solvent to be immersed was changed to normal heptane, and the same test was conducted. The results are shown in Table 3.

  It was confirmed that the resin plates A to D swelled only by being immersed in normal propyl acetate for 1 hour, and the weight increased by 20% by weight or more. Further, it was confirmed that the rubber plate was less likely to swell than the resin plate, and in particular, it was difficult to swell into normal propyl acetate.

<Printing test>
It was confirmed that by using the printing machine of the present invention, a printing film in which ink was fixed with an AC agent could be produced.

In the experiment, a center drum type flexographic printing machine in which the printing unit (first printing unit) located on the most upstream side is provided with a rubber plate and the other printing units are provided with resin plates was used.
As the film base material used in the experiment, a single-layer heat-shrinkable film (thickness: 13 μm, width: 925 mm) made of polypropylene resin not subjected to corona discharge treatment was used.

In the experiment, the AC agent was prepared as follows.
80 L of normal propyl acetate as a solvent was supplied to the container, and further chlorinated polypropylene (chlorination degree 26, weight average molecular weight 100,000) was charged. In addition, a weight average molecular weight shows the value measured on condition of the following by gel permeation chromatography (GPC) method.
Measuring device: High-speed GPC device (“HLC-8220GPC” manufactured by Tosoh Corporation)
Column: The following columns manufactured by Tosoh Corporation were connected in series.
"TSKgel G5000" (7.8 mm ID x 30 cm) x 1 "TSKgel G4000" (7.8 mm ID x 30 cm) x 1 "TSKgel G3000" (7.8 mm ID x 30 cm) x 1 “TSKgel G2000” (7.8 mm ID × 30 cm) × 1 detector: RI (differential refractometer)
Column temperature: 40 ° C
Eluent: Tetrahydrofuran (THF)
Flow rate: 1.0 mL / min Injection amount: 100 μL (tetrahydrofuran solution with a sample concentration of 0.4 mass%)
Standard sample: A calibration curve was prepared using the following standard polystyrene.
(Standard polystyrene)
"TSKgel standard polystyrene A-500" manufactured by Tosoh Corporation
"TSKgel standard polystyrene A-1000" manufactured by Tosoh Corporation
"TSKgel standard polystyrene A-2500" manufactured by Tosoh Corporation
"TSKgel standard polystyrene A-5000" manufactured by Tosoh Corporation
"TSKgel standard polystyrene F-1" manufactured by Tosoh Corporation
"TSKgel standard polystyrene F-2" manufactured by Tosoh Corporation
"TSKgel standard polystyrene F-4" manufactured by Tosoh Corporation
"TSKgel standard polystyrene F-10" manufactured by Tosoh Corporation
"TSKgel standard polystyrene F-20" manufactured by Tosoh Corporation
"TSKgel standard polystyrene F-40" manufactured by Tosoh Corporation
"TSKgel standard polystyrene F-80" manufactured by Tosoh Corporation
"TSKgel standard polystyrene F-128" manufactured by Tosoh Corporation
"TSKgel standard polystyrene F-288" manufactured by Tosoh Corporation
"TSKgel standard polystyrene F-550" manufactured by Tosoh Corporation
The chlorination degree was measured according to JIS-K7229.
The ink used in the experiment was XS-716 507 primary color indigo (SO), XS-716 709 white (SO) (manufactured by DIC Graphics Co., Ltd.).

[Example 1]
The AC agent is applied in the first unit provided with the rubber plate, and then the ink (XS-716 507 indigo) is applied in the second printing unit provided with the resin plate, and further applied to the third printing unit provided with the resin plate. Ink (XS-716 709 white) was applied to produce a printed film. The printing speed was 150 m / min.

[Example 2]
A printing film was produced in the same manner as in Example 1 except that the printing speed was 300 m / min.

About the film obtained in the Example, (1) Tape peeling test, (2) Scratch test, (3) Scratch test with nail | claw were evaluated in the following ways, and the adhesiveness of ink was evaluated.
[Tape peeling test]
Sellotape (registered trademark) no. 405 is applied, and the tape is lightly pressed once with the belly of the finger, and then the tape is immediately peeled off (the peeling speed is slow). Affixing and peeling the tape five times at the same location, sticking the peeled tape to black paper, and calculating the ratio of the peeled area.
The percentage of peeled area is less than 10% 10 points, 10% to less than 15% 9 points, 15% to less than 20% 8 points, 20% to less than 30% 7 points 30% or more and less than 40%, 6 points, 40% or more and less than 50%, 5 points, 50% or more and less than 60%, 4 points, 60% or more and less than 70%, 3 points, 70 % And less than 80% are evaluated as 2 points, and 90% and more are evaluated as 1 point.

[Fir test]
Cut the printed film into a rectangle with a width of 2.5 cm and a length of 10 cm, half-fold with the printed surface of the film inside, and then half-fold (four-fold), and rub the printed surfaces 50 times. Thereafter, the ratio of the peeled area is calculated.
In the same manner as in the tape peeling test, the ratio of the peeled area is evaluated by a score.
[Scratch test with nail]
Nail the nail 50 times at the same location. A cutter mat is used for the base.
In the same manner as in the tape peeling test, the ratio of the peeled area is evaluated by a score.

  The printed films obtained in Examples 1 and 2 were evaluated after 1 day from printing and after 7 days from printing. The evaluation results are shown in Table 4. In addition, the printed film after 1 day from printing was evaluated by shrinking it at 170 ° C. by 30%. The results are shown in Table 5. Furthermore, the printed film after 1 day from printing was evaluated after shrinking by 50% at 180 ° C. The results are shown in Table 6. In any of the tests, 6 to 7 points is a criterion, and those exceeding it are acceptable.

  It was confirmed that the ink fixability was sufficient before and after heat shrinkage. Further, from Table 4, it was confirmed that the fixing property of the ink was improved with time. Further, from Tables 4 to 6, it was confirmed that the ink fixing property was improved by thermally shrinking the film. Furthermore, from the results of Tables 5 and 6, it was confirmed that the sample was firmly fixed on the film base material after 30% shrinkage and after 50% shrinkage for the sample one day after printing. did it.

DESCRIPTION OF SYMBOLS 1 Flexo printing machine 2 Center drum 10 Printing part 20 Printing unit provided with rubber plate 30 Printing unit provided with resin plate B Base of film base f Film base F Printing film PL Print layer of film POL Polyolefin layer of POL film base ACL Anchor layer of printing layer IcL Ink layer of printing layer

Claims (9)

In a center drum type flexographic printing press comprising a center drum for aligning a film substrate and a plurality of printing units installed around the center drum,
Among the plurality of printing units, one or more printing units positioned on the upstream side include a rubber plate, and a printing unit positioned on the downstream side of the one or more printing units includes a resin plate. Flexographic printing machine. A method for producing a printing film using the flexographic printing machine according to claim 1,
On one surface of the film substrate, using a printing unit comprising the rubber plate, an anchor coating agent coating step of applying an anchor coating agent;
On the anchor coat layer formed by the anchor coating agent coating step, an ink coating step of coating ink using a printing unit including the resin plate, in order, is provided. Production method. The method for producing a printed film according to claim 2, wherein the film substrate is not subjected to corona discharge treatment. The film base is formed of a polyolefin layer containing the polyolefin resin on the one surface,
The anchor coating agent is
The method for producing a printed film according to claim 2 or 3, comprising a polyolefin resin and a solvent for dissolving the polyolefin resin. The method for producing a printing film according to claim 4, wherein the solvent contains an ester solvent and / or an ether solvent as a main component. The polyolefin resin contained in the anchor coating agent is
6. The method for producing a printed film according to claim 4 or 5, wherein the chlorinated polyolefin has a chlorination degree lower than 35% and has a weight average molecular weight of 30,000 to 200,000. In a printed film in which a printed layer consisting of an anchor coat layer and an ink layer is intermittently formed on the polyolefin layer of a film substrate comprising a polyolefin layer containing a polyolefin-based resin on at least one surface,
The anchor coat layer is
A chlorinated polyolefin having a chlorination degree lower than 35%, and having a weight average molecular weight of 30,000 to 200,000. The thickness of the said film base material is 5 micrometers-150 micrometers, The printed film of Claim 7 characterized by the above-mentioned. The printed film according to claim 7 or 8, wherein the film substrate is a heat-shrinkable film.

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