JP7085411B2 - A flexographic printing machine and a method for manufacturing a printing film using the printing machine. - Google Patents

Description

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

Products such as cup noodles, lactic acid bacteria beverages, and dry batteries are usually provided and sold in a state of being wrapped in 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 wrapping (heat shrink wrapping).

Shrink wrapping (heat shrink wrapping) has various merits (for example, it is possible to wrap a film in close contact with an article to be packaged regardless of the shape of the article to be packaged. Even a plurality of articles can be fixedly held and packaged together. Since it has the ability to do so, etc.), it is being increasingly adopted for packaging various items to be packaged. Then, in order to improve the appearance and obtain the advertising effect, various patterns and characters are printed on the heat-shrinkable film itself to be wrapped.

As the material of the heat-shrinkable film, a polyolefin-based resin that is easily heat-sealed and heat-shrinked is usually used, but a polypropylene-based resin that becomes highly glossy when formed into a film is preferably used.
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 the fixability of the ink is lowered. Therefore, when printing on the polyolefin-based resin layer, a method is adopted in which the film is subjected to a corona discharge treatment in advance 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 lowering the heat sealing property. During shrink wrapping, the heat-shrinkable film is cut to a suitable size to cover the packaged article and the edges are heat-sealed.
When the printed surface and the heat-sealed surface are different (in the case of so-called front printing), the heat-sealed surface is not subjected to the corona discharge treatment, so that the strength of the heat-sealed portion is maintained. However, since the print 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 heat-sealed surface are the same (in the case of so-called back printing), the print is not located on the outermost surface of the shrink package, and the risk of the print being peeled off or scratched is low. However, the surface to be heat-sealed is subjected to the corona discharge treatment, and the strength of the heat-sealed portion is weakened. Then, there is a problem that the heat-sealed portion opens immediately after packaging or in a shrinking tunnel after that.
In order to solve such a problem, it was also considered to perform corona discharge treatment except for the part to be heat-sealed in the subsequent process. However, due to its structural characteristics, the corona discharge treatment can set a portion that is not processed in parallel with the flow direction of the film, but an unprocessed portion is set accurately in parallel with the width direction of the film. I couldn't.

Conventionally, in order to solve the above problem, an anchor coating agent (a polyolefin resin dissolved in a solvent) is intermittently applied to the printed surface of the film substrate except for the portion to be heat-sealed in the subsequent step. A printing method has been proposed in which an anchor coat layer is provided by processing 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 printing layer containing a urethane resin is formed on the anchor coat layer. The technique of forming is disclosed.

Japanese Unexamined Patent Publication No. 2016-141403

By the way, flexographic printing and gravure printing are generally adopted for film printing. Since flexographic printing uses a resin plate made of resin, it is good at printing fine characters and sharp expressions, and in a printing machine that uses a center drum, register accuracy and printing speed are superior to gravure printing. .. On the other hand, gravure printing is good at printing expressions such as shadows, textures, and gradations because it can clearly print shades. Since a metal plate made of metal is used, the durability of the plate is superior to that of flexographic printing using a resin plate made of resin.

The technique of Patent Document 1 has problems such as difficulty in reproducing fine characters and sharp expressions compared to flexographic printing, and also uses a large amount of ink compared to flexographic printing, so that a large amount of solvent is used. There is also the 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 the flexographic printing machine is easily swollen by an organic solvent such as toluene, when the coating liquid described in Patent Document 1 is applied to the film substrate by the flexographic printing machine, the resin plate immediately swells, which is desired. It becomes impossible to apply the amount of coating liquid.

Further, since the anchor coating agent is transparent, it is not possible to detect the coated position with a sensor or the like and correct the deviation of the coated position. Therefore, in the technique disclosed in Patent Document 1, it is difficult to accurately register (align) the anchor coat layer and the design print layer. The heat-shrinkable film of the thin film may have some elongation between the printing units, and it is particularly difficult to register the film.

In view of the above circumstances, an object of the present invention is to provide a printing machine capable of performing high-quality printing for a long period of time even on a film substrate that has not been subjected to corona discharge treatment. Another object of the present invention is to provide a method for manufacturing a printing film using the printing machine .

(Flexographic printing machine)
The flexo printing machine of the first invention is a center drum type flexographic printing machine including a center drum for aligning a film substrate and a plurality of printing units installed around the center drum. Among the printing units, one or a plurality of printing units located on the upstream side are provided with a rubber plate, and a printing unit located on the downstream side of the one or a plurality of printing units is provided with a resin plate.
(Manufacturing method of printing film)
The method for producing a printing film of the second invention is a method for producing a printing film using the flexographic printing machine of the first invention, wherein a printing unit provided with the rubber plate on one surface of a film substrate is used. Anchor coating agent coating process for applying an anchor coating agent and ink coating for applying ink on an anchor coating layer formed by the anchor coating agent coating process using a printing unit provided with the resin plate. It is characterized by preparing the construction process in order.
The method for producing a printing film of the third invention is characterized in that, in the second invention, the film substrate is not subjected to the corona discharge treatment.
In the method for producing a printing film of the fourth invention, in the second invention or the third invention, the film base material has one surface formed of a polyolefin layer containing a polyolefin resin, and the anchor coating agent is a method. It is characterized by containing a polyolefin-based resin and a solvent for dissolving the polyolefin-based resin.
The method for producing a printing film of the fifth invention is characterized in that, in the fourth invention, the solvent contains an ester solvent and / or an ether solvent as a main component.
In the method for producing a printing film of the sixth invention, in the fourth invention or the fifth invention, the polyolefin-based resin contained in the anchor coating agent is a chlorinated polyolefin having a degree of chlorination of less than 35%, and the weight average. It is characterized by having a molecular weight of 30,000 or more and 200,000 or less.

(Flexographic printing machine)
According to the first invention, since the printing unit located on the upstream side is provided with a rubber plate, even an anchor coating agent containing a solvent that swells the resin plate can be applied to the film substrate by the printing unit. can. Further, since the printing unit located on the downstream side is provided with a resin plate, it is possible to print fine characters and sharp expressions by applying ink with the printing unit. Further, by adopting the center drum method, the elongation of the film base material is suppressed, and even a transparent anchor coating agent can be coated without causing misalignment.
(Manufacturing method of printing film)
According to the second invention, since a printing film having an anchor coat layer between the film base material and the ink layer can be manufactured, the ink can be appropriately fixed on the film base material. Further, since the anchor coating agent is applied by the rubber plate, the swelling of the plate is suppressed, and continuous printing can be performed for a long period of time.
According to the third invention, since the film base material is not subjected to the corona discharge treatment, the heat-sealing property of the obtained printed film is good, and the heat-sealing portion is difficult to open (peeling) when the packaged article is packaged. hard).
According to the fourth invention, since the layer to which the anchor coating agent of the film base material is applied and the anchor coating agent both contain the polyolefin resin, the anchor coating agent can be appropriately fixed to the film base material. can.
According to the fifth invention, since the solvent contained in the anchor coating agent contains an ester solvent and / or an ether solvent as a main component, it is possible to reduce the burden on the operator and the environmental load.
According to the sixth invention, since the polyolefin-based resin contained in the anchor coating agent has predetermined physical properties, the polyolefin-based resin is appropriately dissolved in an ester-based solvent and / or an ether-based solvent, particularly an ester-based solvent. The ink can be firmly fixed by the film base material .

It is a schematic explanatory drawing of the printing film F of this embodiment. (A) is a schematic explanatory view of the flexo printing machine 1 of the present embodiment provided with the printing units 20 and 30, and (B) is a rubber arranged around the center drum 2 of the flexo printing machine 1 of the present embodiment. It is a schematic explanatory drawing of a plate printing unit 20.

The flexographic printing machine of the present embodiment is a device for printing a pattern or the like on one surface of a film base material, and even if the surface is a polyolefin layer, the pattern or the like can be appropriately printed without corona discharge treatment. be able to.

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

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

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

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

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

The film base material f is not particularly limited as long as it has the polyolefin layer POL as described above.
The film base material f may be a single-layer film, for example, as shown in FIG. 1, a structure in which a base B and a polyolefin layer POL are laminated, and another resin layer is provided between the base B and the polyolefin layer POL. It may be configured such that another resin layer is laminated on the surface of the base B opposite to the polyolefin layer POL.

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

Further, as the film base material f, those having various uses can be used.
For example, a heat-shrinkable film used for shrink wrapping, a wrap film for food packaging, a film for decorating building materials, a stretched film used for laminating, and the like can be used as a film base material.

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

In the flexographic printing machine 1 of the present embodiment, since the film base material f is printed and conveyed along the center drum, it is difficult for the film base material f to stretch between the printing units. Therefore, even a thin film having a film base material f of less than 10 μm can be suitably printed.

Further, it is desirable that the film base material f used in the flexographic printing machine 1 of the present embodiment is not subjected to the corona discharge treatment. When the corona discharge treatment is applied, it becomes difficult to heat-seal the print film F when packaging the packaged article.

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

In the printing film F of the present embodiment, the AC layer ACL contains a polyolefin-based 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, the chlorinated polyolefin-based resin such as the chlorinated polyethylene-based resin and the chlorinated polypropylene-based resin has an excellent function of fixing the ink layer IcL on the film base material f, and is an AC agent used for forming the AC layer ACL described later. It also has good solubility in an ester solvent and / or an ether solvent which is a solvent.

When the polyolefin layer POL of the film base material f contains a polypropylene-based resin as a main component, it is desirable that the AC layer ACL contains a chlorinated polypropylene-based resin and an acrylic modified polypropylene-based resin, and particularly contains a chlorinated polypropylene-based resin. Is desirable.

The chlorine content in the chlorinated polyolefin resin may be any one that can be dissolved in a solvent having a reduced impact 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%. If the degree of chlorination is lower than 20%, it is easy to adhere to the film base material f, but it is difficult to dissolve in the solvent. On the other hand, when the degree of chlorination is higher than 35%, it becomes easy to dissolve in the solvent, but it becomes difficult to adhere to the film base material f.
Therefore, from the viewpoint of solubility in the solvent and adhesiveness to the film substrate f, the degree of chlorination of the polyolefin resin contained in the AC layer ACL is preferably 35% or less, more preferably 20% to 35%. be. In particular, from the viewpoint of environment and workability, the degree of chlorination of the polyolefin resin is adjusted to be 30% or less, preferably 25% to 30%.
In this case, it is desirable that the solvent of the AC agent used for forming the AC layer contains an ester solvent as a main component. The ester solvent may be a chlorinated polyolefin resin having a low chlorine content, but it can be appropriately dissolved and the adhesiveness to the film substrate f can be maintained. When using an ether solvent, it is desirable to mix it 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 and the adhesive force is lowered. On the other hand, when the weight average molecular weight is larger than 200,000, the compatibility is lowered and the solubility in the solvent is lowered.
Therefore, from the viewpoint of adhesive strength and solubility, it is preferable to adjust the weight average molecular weight of the polyolefin resin contained in the AC layer to be 30,000 to 200,000, more preferably 30,000 to 150,000.

In particular, from the viewpoint of environment and workability, the weight average molecular weight of the polyolefin resin is adjusted to be 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 an ester solvent and / or a solvent having a reduced influence on the environment such as an ether solvent, the above-mentioned polyolefin resin is appropriately dissolved and the film substrate is used. You will be able to bond.

The ink layer IcL of the printing layer PL is a layer constituting a product name, a photograph of a product, a design such as an image diagram, or the like of a packaged body such as cup noodles, lactic acid bacteria beverages, dry batteries, beverage bottles, and foods.

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

The thickness of the print layer PL is not particularly limited.
For example, the print layer PL can be formed so that the thickness is 1 μm to 20 μm. Further, the thicknesses of the AC layer ACL and the ink layer IcL of the print layer PL are 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 into. For example, if the thickness of the AC layer ACL is 1 μm and the ink layer IcL is printed in two colors with a thickness of 1 μm, a print layer PL having a thickness of 3 μm can be formed.

The printing film F of the present embodiment is provided with a printing layer intermittently. That is, the print film F has a portion in which 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 the portion.

Further, in the print film F of FIG. 1, the shapes of the AC layer ACL and the ink layer IcL are the same, but the sizes thereof may be different. If the ink layer IcL and the film base material f do not come into contact with each other 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 printed solidly except for the portion to be heat-sealed in the subsequent process, and the ink layer IcL may be printed according to the pattern.

<Flexographic printing machine 1>
Next, the flexographic printing machine 1 of the present embodiment will be specifically described.
FIG. 2A shows an outline of the flexographic printing machine 1 (hereinafter, simply referred to as the 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. 2A, the center drum 2 of the flexographic printing machine 1 is a cylindrical roll, and if the film base material f is rotated along the supplied film base material f, the film base material f can be obtained. It can be transported to the side opposite to the side to which it was supplied.
In FIG. 2A, the center drum 2 rotates counterclockwise about the axis of rotation.

A film base material supply roller and a film discharge roller are provided in the vicinity of the center drum 2.
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 located second from above the paper surface in FIG. 2A) is provided. There is. On the other hand, a film ejection 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 forming the print layer PL is ejected from the center drum 2. The roller supports and conveys the printing film F from the non-printed surface.

The flexographic printing machine 1 includes a printing unit 10 for applying an AC agent or ink to the printing surface fs of the film base material f on the center drum 2.
The printing unit 10 includes a printing unit (hereinafter, abbreviated as “rubber plate printing unit”) 20 having a rubber plate arranged along the circumferential direction of the center drum 2 and a printing unit (hereinafter, “resin”) including a resin plate. (Abbreviated as "plate printing unit") 30 and.
In the flexographic printing machine 1 of the present embodiment, the rubber plate printing unit 20 is located on the upstream side where the film base material f is supplied, and the resin plate printing unit 30 is arranged downstream of the rubber plate printing unit 20. Will be done.
The rubber plate printing unit 20 can be coated for a long period of time even with an AC agent using an ester solvent and / or an ether solvent. Further, 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 rubber plate printing unit 20 and three resin plate printing units 30 (resin plate printing units 30A, 30B, 30C). can do. Further, the printing unit 10 may be configured to include two rubber plate printing units 20 and three resin plate printing units 30 (resin plate printing units 30A, 30B, 30C). In this case, two rubber plate printing units 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 characteristic 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 is referred to as the printing unit 20. It will be described as a representative of 30.

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 substrate f, and a supply unit 25 that supplies the coating liquid to the printing unit 21. And have.

As shown in FIG. 2, the printing unit 21 of the rubber plate printing unit 20 includes a cylindrical roller 23 and a sheet-shaped printing plate 22 wound and fixed around the roller 23. Then, the printing unit 21 rotates in the direction opposite to that of the center drum 2. For example, when the center drum 2 rotates counterclockwise, the printing unit 21 is arranged so as 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 a plate whose entire plate is made of rubber and a plate whose surface is made of rubber and whose other base material layer is made of resin. The printing plate 22 is preferably made entirely of rubber from the viewpoint of improving the durability against organic solvents.

The rubber material used for the printing plate 22 is not particularly limited to that used for the conventional rubber plate.
Examples of such rubber include chloroprene rubber, ethylene propyl rubber, chlorosulfonated polyethylene rubber, styrene butadiene rubber, silicon rubber, fluororubber, 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 depending on the application.

As shown in FIG. 2, the supply unit 25 of the rubber plate printing unit 20 has a supply roll for supplying the coating liquid to the printing plate 22 of the printing unit 21 and a chamber for supplying the coating liquid to the supply roll. Be prepared.

The supply roll of the supply unit 25 rotates in the direction opposite to that of the printing plate 22 of the printing unit 21. For example, the supply roll is a member having the same function as the anilox roll used in a known flexographic printing facility. If this supply roll is provided so as to be removable, the image quality can be easily adjusted.
The chamber of the supply unit 25 has a structure capable of supplying the held coating liquid to the supply roll while holding 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 supply, respectively. Corresponds to the supply roll and chamber of the part.

Further, the coating liquid contains the AC agent when used in the rubber plate printing unit 20, and contains 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, but in the resin plate printing unit 30, the surface material of the printing plate is resin.
As the resin used for the printing plate in the resin plate printing unit 30, it is desirable to use a photosensitive resin in consideration of ease of plate production, printing accuracy, and the like. Among them, a photosensitive resin composed of a mixture of a prepolymer, an acrylate oligomer, and an acrylate monomer having an acrylate as a main skeleton such as urethane, polyester, and polybutadiene, and a photopolymerization inhibitor, a photopolymerization initiator, and the like is preferable. Used.

<Manufacturing method of printing film F>
Since the flexographic printing machine 1 of the present embodiment has the above configuration, the above-mentioned film F can be manufactured by the method shown below by using the flexographic printing machine 1.
The method for producing the printing film F of the present embodiment includes an anchor coating agent coating step of applying an anchor coating agent to one surface of the film base material f using a printing unit 20 provided with a rubber plate, and the anchor coating. The anchor coat layer formed by the agent coating step is characterized by sequentially comprising an ink coating step of coating ink by using a printing unit 30 provided with a resin plate.

Prior to printing, the film base material f is first supplied to the surface of the center drum 2 from the film base material supply roller side of the flexographic printing machine 1, further discharged from the discharge roller side, and installed on the surface of the center drum 2. The print film F discharged from the film discharge roller is wound by a take-up portion (not shown).

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

As shown in FIG. 2A, in the flexo printing machine 1, the rubber plate printing unit 20, the resin plate printing unit 30A, the resin plate printing unit 30B, and the resin plate printing unit 30C are arranged in this order from the film substrate supply roller side. If so, the printing surface fs of the film substrate f is first coated with an AC agent by the rubber plate printing unit 20 to form an AC layer ACL (AC agent coating step). Then, ink is applied and printed on the AC layer ACL by the resin plate printing units 30A, 30B, and 30C to form an ink layer IcL (ink coating step).

Since the flexographic printing machine 1 of the present embodiment employs the center drum method as described above, the ink layer IcL can be printed on the AC layer ACL so as not to be displaced 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. Therefore, the printing film F having excellent quality can be efficiently produced.

Here, as the solvent of 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, when the AC agent used in the flexo printing machine 1 of the present embodiment is printed, the printing plate causes problems such as swelling due to the solvent contained in the AC agent. .. If printing is performed using a printing plate in which such a problem occurs, problems such as poor coatability of the AC agent, unstable coating amount, and inability to print in a desired shape are likely to occur. Moreover, since such swelling progresses after several to several tens of uses, there arises a problem that the printing plate must be replaced at short intervals.

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

In particular, if an ester solvent and / or an ether solvent is used as the solvent for the AC agent, it is possible to reduce the burden on the operator and the environmental load during manufacturing as compared with a solvent such as toluene and the like.
Further, since the swelling of the printing plate 22 of the rubber plate printing unit 20 can be suppressed more appropriately, the usage period of the printing plate 22 can be extended and the production efficiency can be improved.

When an ester solvent and / or an ether solvent is used as the solvent for the AC agent, the polyolefin resin contained in the AC agent has the above-mentioned physical properties (degree of chlorination, weight average molecular weight). For example, it 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 photosensitive resin were immersed in normal propyl acetate. The weight change of each plate was confirmed 1 hour, 4 hours, and 24 hours after the immersion. The rate of increase in weight is shown in Table 1.

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

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

<Printing test>
It was confirmed that by using the printing machine of the present invention, it is possible to produce a printing film in which ink is fixed by an AC agent.

In the experiment, a center drum type flexographic printing machine was used in which the printing unit (first printing unit) located at the most upstream was equipped with a rubber plate and the other printing units were equipped with a resin plate.
As the film substrate used in the experiment, a single-layer heat-shrinkable film (thickness 13 μm, width 925 mm) made of a polypropylene-based resin that had not been subjected to corona discharge treatment was used.

In the experiment, the AC agent was prepared as follows.
80 L of normal propyl acetate was supplied to the container as a solvent, and chlorinated polypropylene (chlorination degree 26, weight average molecular weight 100,000) was further added. The weight average molecular weight indicates a value measured under the following conditions by a 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 and used.
"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 This "TSKgel G2000" (7.8 mm ID x 30 cm) x 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% by 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 degree of chlorination was measured according to JIS-K7229.
The inks used in the experiment were XS-716 507 primary color indigo (SO) and XS-716 709 white (SO) (manufactured by DIC Graphics Corporation).

[Example 1]
The AC agent is applied to the first unit equipped with the rubber plate, then the ink (XS-716 507 indigo) is applied to the second printing unit equipped with the resin plate, and further to the third printing unit equipped with the resin plate. Ink (XS-716 709 white) was applied to produce a printing 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 set to 300 m / min.

The films obtained in the examples were subjected to (1) tape peeling test, (2) fir test, and (3) scratch test with nails in the following manner to evaluate the adhesion of ink.
[Tape peeling test]
Cellotape (registered trademark) No. on the printed surface. After applying 405 and lightly pressing the tape with the pad of a finger once, the tape is immediately peeled off (the peeling speed is slow). The tape is attached and peeled to the same place 5 times, and the peeled tape is attached to black paper to calculate the ratio of the peeled area.
The percentage of peeled area is 10 points for less than 10%, 9 points for 10% or more and less than 15%, 8 points for 15% or more and less than 20%, and 7 points for 20% or more and less than 30%. , 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 A score of% or more and less than 80% is evaluated as 2 points, and a score of 90% or more is evaluated as 1 point.

[Fir test]
Cut the printing film into a rectangle with a width of 2.5 cm and a length of 10 cm, fold it in half with the printing side of the film inside, then fold it in half (fold in four), and rub the printed surfaces 50 times. After that, the ratio of the peeled area is calculated.
Similar to the tape peeling test, the percentage of peeling area is evaluated by points.
[Scratch test with nails]
Rub the same spot 50 times with your nails. A cutter mat is used as the base.
Similar to the tape peeling test, the percentage of peeling area is evaluated by points.

The printing films obtained in Examples 1 and 2 were evaluated one day after printing and seven days after printing. The evaluation results are shown in Table 4. Further, the printed film one day after printing was shrunk at 170 ° C. by 30% and then evaluated. The results are shown in Table 5. Further, the printed film one day after printing was shrunk at 180 ° C. by 50% and then evaluated. The results are shown in Table 6. In each test, 6 to 7 points are the criteria, and those exceeding that are passed.

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

1 Flexographic printing machine 2 Center drum 10 Printing unit 20 Printing unit with rubber plate 30 Printing unit with resin plate B Base of film base material f Film base material F Printing film PL Film printing layer POL Film base material polyolefin layer ACL Anchor coat layer of the print layer IcL Ink layer of the print layer

Claims (6)

In a center drum type flexographic printing machine including 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 a plurality of printing units located on the upstream side are provided with a rubber plate, and a printing unit located on the downstream side of the one or a plurality of printing units is provided with a resin plate. Flexographic printing machine. A method for manufacturing a printing film using the flexographic printing machine according to claim 1.
An anchor coating agent coating process in which an anchor coating agent is applied to one surface of a film substrate using a printing unit provided with the rubber plate.
A printing film characterized by sequentially comprising an ink coating step of coating ink on an anchor coat layer formed by the anchor coating agent coating step by using a printing unit provided with the resin plate. Production method. The method for producing a printing film according to claim 2, wherein the film substrate is not subjected to a corona discharge treatment. One of the surfaces of the film base material is formed of a polyolefin layer containing a polyolefin resin.
The anchor coating agent is
The method for producing a printing film according to claim 2 or 3, further comprising a polyolefin-based resin and a solvent for dissolving the polyolefin-based 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
The method for producing a printing film according to claim 4 or 5, wherein the chlorinated polyolefin has a degree of chlorination of less than 35% and has a weight average molecular weight of 30,000 or more and 200,000 or less.

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