JP2021088410A - Method for printing food packaging material and food packaging material - Google Patents

Abstract

To provide surface printing with an aqueous inkjet ink to a food packaging material which is made of a plastic film and increase a speed in a printing step.SOLUTION: In printing a pattern and/or a character 1 at a surface positioned on a front side of a plastic film S to constitute a food packaging material, a method for printing a food packaging material includes the steps of; printing a pattern and/or a character by jetting an inkjet ink; and then printing with a transparent UV ink by causing the ink to overlap on the printing region.SELECTED DRAWING: Figure 1

Description

The present invention relates to a plastic film packaging material used for a packaging bag for accommodating a food product and a lid of a food container, and more particularly to a printing method for the packaging material.

Today, when distributing food products, instead of face-to-face sales in which food products prepared on the spot are packaged and sold, packaged food products prepared in advance at food factories, such as processed foods, breads, and confectionery, are used as convenience products. The method of selling at retail stores such as stores and supermarkets is becoming mainstream.

In the above-mentioned sales method, the packaged food is displayed on a display shelf in a retail store, and the customer picks it up and examines it when purchasing. Therefore, it is necessary to devise a design for the packaging itself so as to attract customers'purchasing motivation and make it easier for customers to see.

In the above case, since the main purpose of the packaging bag or the lid of the food container itself is to wrap food, it is not possible to change the shape so as to impair its function, and the design and the design applied to the surface The role of / or characters (hereinafter referred to as "designs, etc.") is very important.

Printing is generally used as a means for applying the above-mentioned patterns to the lids of packaging bags and food containers, and when printing on the lids of packaging bags and food containers, printing is performed on the back side of these (back printing). There are two types of printing methods, one is to print on the front side and the other is to print on the front side (front printing). In this case, in food packaging materials, the Food Sanitation Law prohibits printing ink from coming into contact with food, so when printing on the back side of these, the packaging function is provided on the printing layer side of the plastic film. The plastic film had to be laminated.

On the other hand, when printing on the front side of the packaging material, there are no restrictions as described above, but since the printing layer is exposed, it is printed on the back side of the film when it is printed on the packaging bag or lid. Care must be taken to prevent the printed layer from becoming unclear due to physical friction or solvent (alcohol or oil) due to contact with other packaging materials or articles during distribution or exhibition, or with human fingers. did not become.

In the above case, since the plastic film is a base material that does not easily absorb liquid unlike paper, gravure printing using gravure ink having high coating adhesion and flexographic printing using flexo ink have been adopted for printing. (For example, Patent Document 1).

By the way, inkjet printing, which does not require plate making for printing and can generate images for printing from digital data, has excellent on-demand properties and should be originally useful for food packaging materials that must print various patterns at any time. However, it could not be adopted.

The reason is that the water-based inkjet ink capable of inkjet printing does not have various physical properties such as abrasion resistance, alcohol resistance, oil resistance, and water resistance, and the ink easily falls off and the coating film adhesion is weak. In this case, since the viscosity of the gravure ink and the flexographic ink having high coating film adhesion is too high, it cannot be used in the inkjet printing in which the ink is ejected from the nozzle and adhered because it cannot be smoothly ejected from the nozzle.

JP 2000-273379

Improves production efficiency for food packaging materials that are consumed in a short period of time rather than fixed durable consumer goods with fixed types of patterns, and that require printing of a wide variety of patterns according to the contents at any time. Therefore, speeding up printing was indispensable.

However, gravure printing and flexographic printing, in which plates must be prepared for new designs and set on the production line each time, take time in the process to start printing, and there is a limit to speeding up. It was.

For example, in the case of food packaging materials in which patterns are printed by gravure printing, it takes a total of 12 days for the work required before printing (block copy submission + plate making) and printing, and other post-processing (film lamination, finishing processing). ), Which took 6 days and a total of 18 days.

Further, as described above, since gravure printing requires time and effort for color separation and plate making, the minimum order lot is inevitably large, and the customer has no choice but to purchase more packaging material than necessary, resulting in waste loss.

On the other hand, it is easy to choose to adopt inkjet printing when printing on the back side of a bag or lid, but this requires a process of laminating a plastic film on the printing layer side of the plastic film, which requires cost and time. A problem that requires

The present invention has been created for the purpose of providing a printing method for a food packaging material and a food packaging material that solves the above-mentioned problems.

That is, the method for printing a food packaging material made of a plastic film of the present invention uses an inkjet ink to print a pattern and / or characters on a surface located on the front side of the plastic film to be composed of the food packaging material. It is characterized in that after the design and / or characters are inkjet printed, a transparent UV ink (ultraviolet curable ink) is overprinted on the printing area.

The invention according to claim 2 is characterized in that, in the method for printing a food packaging material made of a plastic film, the transparent UV ink is printed on the entire surface of the film.

The invention according to claim 3 is characterized in that, in the method for printing a food packaging material made of a plastic film, the inkjet ink for printing a pattern and / or characters is a water-based inkjet ink or an oil-based inkjet ink. To do.

Further, the invention according to claim 4 is characterized in that, in the method for printing a food packaging material made of a plastic film, the food packaging material is for forming a food packaging bag.

Further, the invention according to claim 5 is characterized in that, in the method for printing a food packaging material made of a plastic film, the food packaging material is for forming a lid of a food container.

Further, the food packaging material made of a plastic film for a food packaging bag according to claim 6 has a printing layer of patterns and / or characters by inkjet ink and a printing layer by transparent UV ink that covers the surface of the printing layer. Is provided on the surface located on the outside of the bag when the bag is made.

Further, the food packaging material for the lid of the food container according to claim 7 is covered with a printing layer of patterns and / or characters by inkjet ink and a printing layer by transparent UV ink covering the surface of the printing layer. It is characterized in that it is provided on the surface located on the front side of the lid when the lid is closed.

According to the printing method of a food packaging material made of a plastic film of the present invention, when printing a pattern or the like on a surface located on the front side of a packaging bag or a lid of a food container, inkjet printing is performed using an aqueous inkjet ink. However, since the transparent UV ink is overprinted on the print area and cured to protect the print layer such as a pattern, the print layer such as a pattern is not exposed. Therefore, when printing on a packaging bag or lid and winding the film, it may come into contact with the back surface of the film, or it may come into contact with other packaging materials or articles during distribution or exhibition, or with human fingers. This prevents the printed layer from becoming unclear due to physical friction or a solvent (alcohol or oil).

Printing patterns and the like using UV ink is well known in other technical fields. However, when this is applied to a food packaging material made of a plastic film, which is a technical field of the present invention, it is cured on the surface of the packaging material in the usage of unwinding a roll and processing the material. The pattern or the like produced by the UV ink swells with respect to the non-printed portion, and the difference in rigidity is generated, so that the pattern is bent when it is wound on the roll. On the other hand, in the present invention, since the transparent UV ink is printed on the entire surface of the film, the thickness of the film is uniform and the rigidity is also uniform, so that the above situation is avoided.

Inkjet ink also has the advantage that the print expression is closer to gravure printing than UV ink.

In the above case, since printing is performed on the front surface of the food packaging material, there is no laminating step of a protective plastic film as in the case of printing on the back surface, and printing is performed on a single-layer film or a pre-laminated laminated raw fabric. It can be made into a product immediately.

Further, even if there is a barrier film, aluminum foil, or a base material that requires a retort function, it can be laminated first and then printed on the front.

On the other hand, since printing is completed by inkjet printing with excellent on-demand characteristics, we have to prepare a plate for new patterns and set it on the production line, and start printing like gravure printing and flexographic printing. It is possible to speed up the process without taking the time required for the process, and dramatically improve the production efficiency of food packaging bags, which must be printed with a wide variety of patterns according to the contents. be able to.

In addition, since printing is completed by inkjet printing with excellent on-demand characteristics, it is possible to receive orders in the smallest and smallest lots, customers do not have to purchase more packaging materials than necessary, there is no waste loss, and the global environment. Contribute to.

Further, since the UV ink is printed on the entire surface of the film, heat resistance can be obtained, and there is an advantage that it is most suitable for a food packaging material to be boiled in hot water or heated in a microwave oven.

The conceptual diagram which shows the process of the printing method of the food packaging material made of the plastic film of this invention. The conceptual diagram which shows the process of the printing method of the food packaging material made of the plastic film of this invention. The perspective view of the food packaging bag made by the food packaging material made of the plastic film of the present invention. FIG. 3 is a perspective view of a different aspect of a food packaging bag manufactured by the food packaging material made of a plastic film of the present invention. FIG. 3 is a perspective view of a food container having a lid formed of a food packaging material made of a plastic film of the present invention.

Hereinafter, specific examples of the present invention will be described with reference to the accompanying drawings. The food packaging material of the present invention is composed of a plastic film S.

Printing of a pattern, etc. 1 is performed on the plastic film S at the stage before processing it into a packaging bag or lid, and the inkjet printer is driven by the digital data of the image file such as the generated pattern to drive the plastic film packaging bag or the like. A pattern or the like 1 is printed on the surface that becomes the surface when the lid is processed using a water-based inkjet ink (Fig. 1).

Next, a transparent UV ink 2 is printed on the entire surface of the film S on which the pattern 1 is printed by flexographic printing or the like, and the liquid is cured to a solid by irradiating with ultraviolet rays (FIG. 2).

FIG. 3 is a diagram showing a gassho bag using the printed plastic film S, and the bag is made by heat-sealing one end portion H1 and the gassho portion H2 of the cylinder.

Similarly, FIG. 4 is a diagram showing a three-sided bag using the printed plastic film S, and the bag is made by heat-sealing the bottom portion H11 and both side portions H12 and H12.

FIG. 5 is a diagram showing a lid L using the printed plastic film S, and the plastic or paper container P is covered with the lid.

S Plastic film 1 Printing layer of patterns and / or characters (designs, etc.) with inkjet ink 2 Transparent printing layer with UV ink B1 Gassho bag B2 Three-way bag P container L lid

Claims (7)

When printing a pattern and / or characters on the front side of a plastic film that should form a food packaging material, the design and / or characters are inkjet printed using inkjet ink, and then transparent UV ink is overprinted. A printing method for food packaging materials made of plastic film, which is characterized by the fact that The method for printing a food packaging material made of a plastic film according to claim 1, wherein the transparent UV ink is printed on the entire surface of the film. The method for printing a food packaging material made of a plastic film according to claim 1 or 2, wherein the inkjet ink for printing a pattern and / or characters is a water-based inkjet ink or an oil-based inkjet ink. The method for printing a food packaging material made of a plastic film according to any one of claims 1 to 3, wherein the food packaging material is for forming a food packaging bag. The method for printing a food packaging material made of a plastic film according to claims 1 to 3, wherein the food packaging material is for forming a lid of a food container. A food product characterized in that a printing layer of patterns and / or characters using inkjet ink and a printing layer of transparent UV ink covering the surface of the printing layer are provided on a surface located on the outside of the bag when the bag is made. Food packaging material made of plastic film for packaging bags. A food product characterized in that a printing layer of patterns and / or characters using inkjet ink and a printing layer made of transparent UV ink covering the surface of the printing layer are provided on a surface located on the front side of the lid when covered. Food packaging material made of plastic film for lids of ink containers.

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