Plastic container

Abstract

To provide a plastic container with a printing portion that achieves both recyclability and productivity.SOLUTION: A plastic container according to the present disclosure comprises a container body 10 and at least one printing portion 20 which includes a primer layer 21 with alkali detachability and an ink layer 22 provided on the primer layer, all ink cured materials 22a are positioned on primer cured materials 21a, and at least one of the printing portions is an ink amount regulating printed portion 20A, which has a first contour p1 of the printing area of the primer layer and a second contour p2 of the printing area of the ink layer, and includes a contour overlap portion 31 in which the shortest distance between the first contour and the second contour is 0 mm, and / or a contour adjacent portion 32 in which the first contour is outside the second contour and the shortest distance between the first contour and the second contour is in the range of more than 0 mm and less than 2 mm.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates to plastic containers. [Background technology]

[0002] There is a growing trend to conserve resources, and there is a demand to reduce single-use plastics. Labels on plastic containers, including PET bottles, are discarded after their intended use is completed, and plastic labels in particular are difficult to recycle, leading to a very high disposal rate. In order to achieve a label-less environment, a technology has been developed for directly printing on plastic containers (see, for example, Patent Document 1). Patent Document 1 proposes a technology for directly printing necessary product information, such as the product name, ingredients, content, expiration date, and manufacturer, on the bottle.

[0003] In recent years, product information such as that engraved in Patent Document 1 is increasingly being recorded in one- or two-dimensional codes, and devices have been proposed that inspect whether the one- or two-dimensional code information printed on bottles is printed correctly (see, for example, Patent Document 2). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2011-11819 A [Patent Document 2] WO2020 / 071188 publication Summary of the Invention [Problem to be solved by the invention]

[0005] In order to meet the recyclability requirements of label-less plastic containers, it is necessary to reduce the total amount of ink applied to the printed part. On the other hand, as part of efforts to differentiate in the market, the printed part may be required to have a highly aesthetic design image or a large printed area, and measures are required to reduce the total amount of ink applied to the entire printed part, including the design image and product information. In the case of stamp printing as in Patent Document 1, the printing color is only white, and the aesthetic quality of the design image is insufficient. In addition, when a one-dimensional code or two-dimensional code is printed by stamp printing, the code part becomes white, and the code may not be properly identified by a print inspection device that determines the quality of printing by a binary threshold value as in Patent Document 2.

[0006] In recent recycling systems, containers such as PET bottles are crushed and pulverized, and then separated by gravity separation into crushed containers with a high specific gravity and crushed lids with a low specific gravity. This separation is carried out, for example, by an alkaline cleaning process in which the containers are immersed in an alkaline cleaning solution (e.g., an alkaline aqueous solution). When directly printing on the outer surface of a plastic container, it is required that the printed portion be peeled off and separated from the plastic that constituted the container in the alkaline cleaning process.

[0007] In order to ensure the releasability of the ink in the alkaline cleaning process, the printing part may have a primer layer having alkali releasability provided on the outer surface of the plastic container, and an ink layer expressing a predetermined print such as an information image or a design image, such as a one-dimensional code or two-dimensional code, on the primer layer. When the ink layer is printed by the inkjet method, the flight trajectory of the minute ink droplets discharged from the inkjet print head may be affected by air currents, etc., causing a deviation in the landing position on the printed material, and the ink droplets for forming the ink layer may land outside the printing area of ​​the primer layer at the edge of the printing area of ​​the printing part. In such a case, if the ink for forming the ink layer does not have alkali releasability, there is a problem that the printing part does not peel off in the alkaline cleaning process. This problem can be solved by forming the primer layer larger than the printing area of ​​the ink layer, but if the printing area of ​​the primer layer is too large, there is a problem that the amount of primer ink used for the primer layer increases or the application time increases, which reduces productivity, or the amount of peeled off material from the printing part in the alkaline cleaning process increases, causing clogging in the part for draining the cleaning liquid, reducing the recycling workability. A relationship between the printed area of ​​the primer layer and the printed area of ​​the ink layer that can achieve both recyclability and productivity has not yet been found.

[0008] The present disclosure aims to provide a plastic container having a printed portion that is both recyclable and productive. [Means for solving the problem]

[0009] The plastic container according to the present invention is a plastic container comprising: a container body having a mouth and a body connected to the mouth; and at least one printed section including a primer layer having alkali releasability provided on the outer surface of the body and an ink layer provided on the primer layer, wherein the primer layer includes a primer cured product that is a cured product of an active energy ray-curable ink-jet ink for forming a primer layer, the ink layer includes an ink cured product that is a cured product of an active energy ray-curable ink-jet ink for forming an ink layer, and all of the ink cured products are located on the primer cured product, and at least one of the printed sections is an ink amount regulating printed section, which has a first contour of a printed area of ​​the primer layer and a second contour of a printed area of ​​the ink layer, and includes a contour overlap section in which the shortest distance between the first contour and the second contour is 0 mm, and / or a contour adjacent section in which the first contour is outside the second contour and the shortest distance between the first contour and the second contour is in the range of more than 0 mm and not more than 2 mm.

[0010] In the plastic container according to the present invention, it is preferable that all of the printed portions are the ink amount regulating printed portions, which can further improve recyclability and productivity.

[0011] In the plastic container according to the present invention, it is preferable that the total area of ​​the printed region of the ink layer in all of the printed parts is 50 to 95% of the total area of ​​the printed region of the primer layer in all of the printed parts, thereby making it possible to further improve recyclability and productivity. Effect of the Invention

[0012] According to the present disclosure, it is possible to provide a plastic container having a printed portion that is both recyclable and productive. [Brief description of the drawings]

[0013] [Figure 1] 1 is an image showing an example of a plastic container according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a schematic plan view illustrating an example of a printing unit. [Diagram 3] FIG. 3 is a schematic end view taken along line AA in FIG. 2. [Figure 4] FIG. 4 is a schematic enlarged view of a portion of a contour adjacent portion of a printed portion. [Diagram 5] FIG. 11 is a schematic plan view showing another example of a printing unit. [Figure 6] FIG. 6 is a schematic end view taken along line AA in FIG. 5. [Figure 7] FIG. 2 is a schematic plan view showing an example of a body portion. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] The embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited to these descriptions. Various modifications of the embodiments may be made as long as the effects of the present invention are achieved.

[0015] The plastic container 1 according to this embodiment is a plastic container comprising a container body 10 having a mouth portion 11 and a body portion 12 connected to the mouth portion 11, as shown in FIG. 1, and at least one printed portion 20 including a primer layer 21 having alkali releasability provided on the outer surface of the body portion 12 and an ink layer 22 provided on the primer layer 21, as shown in FIG. 2 or FIG. 3, in which the primer layer 21 includes a primer cured product 21a that is a cured product of an active energy ray-curable inkjet ink for forming the primer layer, and the ink layer 22 includes an ink layer 22 formed on the ink layer 22, as shown in FIG. The ink cured product 22a is a cured product of the ink layer 22a, and all of the ink cured product 22a is located on the primer cured product 21a. At least one of the printed parts 20 is an ink amount regulating printed part 20A, and the ink amount regulating printed part 20A has a first contour p1 of the printed area of ​​the primer layer 21 and a second contour p2 of the printed area of ​​the ink layer 22, and includes a contour overlapping part 31 in which the shortest distance between the first contour p1 and the second contour p2 is 0 mm, and / or a contour adjacent part 32 in which the first contour p1 is outside the second contour p2 and the shortest distance between the first contour p1 and the second contour p2 is in the range of more than 0 mm and 2 mm or less. FIG. 1 shows a form in which a one-dimensional code is printed on a solid white print as an example of the printed part 20, and FIG. 2 shows an arbitrary shape for convenience of explanation, but the present invention is not limited to the shape shown in the figure.

[0016] The thermoplastic synthetic resin that is the material of the plastic container 1 is not particularly limited, but examples thereof include polyethylene terephthalate resin (PET), polybutylene terephthalate resin, polyethylene naphthalate resin, polyethylene resin, polypropylene resin (PP), cycloolefin copolymer resin (COC, cyclic olefin copolymer), ionomer resin, poly-4-methylpentene-1 resin, polymethyl methacrylate resin, polystyrene resin, ethylene-vinyl alcohol copolymer resin, acrylonitrile resin, polyvinyl chloride resin, polyvinylidene chloride resin, polyamide resin, polyamideimide resin, polyacetal resin, polycarbonate resin, polysulfone resin, or tetrafluoroethylene resin, acrylonitrile-styrene resin, and acrylonitrile-butadiene-styrene resin. Among these, PET is particularly preferred. The capacity of the plastic container 1 is not particularly limited, and is, for example, 280 ml to 2000 ml.

[0017] The method for molding the plastic container 1 is not particularly limited, but may be, for example, a blow molding method. Specifically, first, a preform is manufactured by injection molding a thermoplastic resin, and then the preform is blow molded to manufacture the plastic container 1 having a shape in which a mouth portion 11 and a body portion 12 are connected in order as shown in FIG.

[0018] The container body 10 has an internal space for accommodating contents. The contents are not particularly limited, but may be, for example, liquids such as beverages, alcoholic beverages, and seasonings, foods, medicines, or industrial products. The beverages may be, for example, white beverages such as milk, yogurt beverages, lactic acid bacteria beverages, milk beverages, and alcoholic beverages, colored and transparent beverages such as straight tea, lemon tea, green tea, fruit juice beverages, carbonated beverages, and beer, cloudy beverages such as milk tea and coffee, or transparent beverages such as sports drinks, water, carbonated water, and chuhai.

[0019] The mouth 11 is a filling port and a pouring port for the contents. A cap (not shown) is attached to the mouth 11 to seal the bottle. A neck support ring may be formed at the lower end of the mouth 11.

[0020] The body 12 is a portion connected to the lower end of the mouth 11, and may have, in order from the mouth 11 side, an upper body 12a whose diameter increases from the lower end of the mouth 11 downward, a cylindrical body main body 12b, and a lower body 12c that is connected to the body main body 12b and has a ground surface with approximately the same diameter as the body main body 12b. The upper body 12a is sometimes called a shoulder due to its shape. The body main body 12b is, for example, cylindrical or regular n-sided cylindrical (where n is an integer of 4 or more). The lower body 12c becomes the bottom of the container body 10.

[0021] The printed section 20 is provided on at least one part of the upper body 12a, the body main body 12b, and the lower body 12c. In FIG. 1, an example is shown in which an identification code section showing a one-dimensional code is provided on the body main body 12b as the printed section 20, but the present invention is not limited to this. When the body 12 has ribs, it is preferable to provide the identification code section in a portion that avoids the ribs. The printed section 20 may include a character string (not shown) or a design image section (not shown) in addition to the identification code section. The character string includes product information such as the product name, raw material name, content amount, expiration date, and manufacturer. The design image section includes, for example, a logo showing the product name or company name, or an image for enhancing design such as a color, a painting, a photograph, an illustration, or a pattern.

[0022] The region where the printed part 20 is provided may be only one or two or more. The printed part 20 is preferably provided in a light-transmitting part of the body 12. The light-transmitting form includes, for example, achromatic and colorless transparent having a visible light transmittance to the extent that the other side of the body 12 can be seen through, chromatic and colorless transparent having a visible light transmittance to the extent that the other side of the body 12 can be seen through, semi-transparent having a visible light transmittance to the extent that the characters on the other side of the body 12 can be read by the light transmitted through the body 12, or opaque having a visible light transmittance to the extent that the characters on the other side of the body 12 cannot be read by the light transmitted through the body 12 but the silhouette can be seen. The container in which at least a part of the body 12 is light-transmitting includes, but is not limited to, a general PET bottle in which the entire body 12 is colorless and transparent, and a foamed PET bottle in which at least a part of the body 12 is semi-transparent or opaque having a visible light transmittance.

[0023] As shown in FIG. 3, the printed portion 20 has a primer layer 21 and an ink layer 22 in this order from the outer surface side of the body portion 12.

[0024] The primer layer 21 is a layer for ensuring adhesion between the body 12 and the ink of the printed portion 20, and is a layer for enabling the entire printed portion 20 to be peeled off and separated from the body 12 when recycling the plastic container 1 due to its alkali peelability. The primer layer 21 has alkali peelability. For example, in a recycling system, containers such as PET bottles are crushed and pulverized, and then sorted into crushed containers having a high specific gravity and crushed lids having a low specific gravity by a specific gravity separation method. This sorting is performed, for example, by immersing the container in a treatment liquid (for example, an alkaline aqueous solution). The primer layer 21 having alkali peelability can make the container excellent in recyclability. The alkali peelability refers to the property that the primer layer 21 peels off from the body 12 when immersed in an alkaline solution. The alkali peelability may be, for example, that the primer layer 21 dissolves in an alkali and peels off from the body 12, or that the primer layer 21 does not dissolve in an alkali and peels off at the interface between the body 12 and the primer layer 21 in the alkaline solution. In this embodiment, the primer layer 21 is preferably such that, for example, when a region of the plastic container 1 including at least the printed portion 20 is immersed and stirred in a 1.5 mass % sodium hydroxide aqueous solution at 85° C. or higher and 90° C. or lower for 15 minutes, at least a portion of the printed portion 20 peels off from the body portion 12. The thickness of the primer layer is not particularly limited, but is preferably 6 to 26 μm, and more preferably 11 to 15 μm.

[0025] The primer layer 21 is a coating film of an active energy ray-curable inkjet ink for forming a primer layer, and includes a cured primer material 21a which is a cured product of the active energy ray-curable inkjet ink for forming a primer layer. The primer layer 21 may consist of only the cured primer material 21a, or may include additives such as a filler or a colorant such as a pigment or dye in addition to the cured primer material 21a.

[0026] The active energy ray curable inkjet ink preferably contains, for example, a polymerizable monomer and a polymerizable surfactant. From the viewpoint of alkali peelability, the polymerizable monomer preferably contains at least a polyfunctional monomer. The polyfunctional monomer is not particularly limited as long as it is a monomer having two or more polymerizable groups. From the viewpoint of curability, the polyfunctional monomer is preferably a polyfunctional radical polymerizable monomer, more preferably a polyfunctional ethylenically unsaturated monomer, for example, 3-methyl-1,5-pentanediol di(meth)acrylate, triethylene glycol di(meth)acrylate, 1,10-decanediol di(meth)acrylate. The polymerizable monomer may further contain a monofunctional monomer in addition to the polyfunctional monomer. The monofunctional monomer is not particularly limited as long as it is a monomer having one polymerizable group. From the viewpoint of curability, the monofunctional monomer is preferably a monofunctional radical polymerizable monomer, more preferably a monofunctional ethylenically unsaturated monomer. Examples of the monofunctional ethylenically unsaturated monomer include monofunctional (meth)acrylate, monofunctional (meth)acrylamide, monofunctional aromatic vinyl compound, monofunctional vinyl ether and monofunctional N-vinyl compound, such as cyclic trimethylolpropane formal (meth)acrylate, 2-(meth)acryloyloxyethyl succinic acid, stearyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate. Examples of the polymerizable surfactant include polymerizable silicone surfactant, polymerizable fluorine surfactant, and polymerizable acrylic surfactant. Commercially available polymerizable silicone surfactants include, for example, BYK-UV3500, 3505, 3530, 3570, 3575, and 3576 (manufactured by BYK), Tegorad 2100, 2200, 2250, 2300, 2500, 2600, 2700, 2800, 2010, and 2011 (manufactured by Evonik), EBECRYL 350 and 1360 (manufactured by Daicel-Allnex Corporation), and KP-410, 411, 412, 413, 414, 415, 416, 418, 420, 422, and 423 (manufactured by Shin-Etsu Silicones), and other silicone surfactants having a (meth)acryloyl group.Examples of the polymerizable fluorosurfactant include compounds having a perfluoroalkyl group and a polymerizable group. Examples of commercially available polymerizable fluorosurfactants include fluorosurfactants having a (meth)acryloyl group, such as Megafac RS-56, RS-72-K, RS-75, RS-76-E, RS-65-NS, RS-78, and RS-90 (manufactured by DIC Corporation). Examples of the polymerizable acrylic surfactant include compounds having a polymerizable group bonded to the side chain of a poly(meth)acrylic structure. Examples of commercially available polymerizable acrylic surfactant include CN821 (manufactured by Sartomer Corporation). The active energy ray curable inkjet ink may contain at least one type of polymerization initiator. The polymerization initiator is preferably a radical polymerization initiator that generates radicals, such as bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide or 1,3-di({α-[1-chloro-9-oxo-9H-thioxanthen-4-yl)oxy]acetylpoly[oxy(1-methylethylene)]}oxy)-2,2-bis({α-[1-methylethylene)]}oxymethyl)propane.

[0027] The ink layer 22 is formed on the primer layer 21 and includes a colored print layer showing letters, numbers, or symbols (hereinafter, letters, numbers, or symbols may be collectively referred to as letters, etc.) and / or design images such as illustrations or icons. Although the ink layer 22 is shown in FIG. 3 as a form consisting of only one layer as an example, the present invention is not limited to this, and may be a form consisting of two or more layers (not shown). The form consisting of two or more layers is, for example, a form having, in order from the primer layer 21 side, a solid print layer and a colored print layer showing letters, etc. and / or design images.

[0028] The ink layer 22 is a coating film of the active energy ray-curable inkjet ink for forming the ink layer, and includes an ink cured product 22a that is a cured product of the active energy ray-curable inkjet ink for forming the ink layer. The ink layer 22 may or may not have alkali releasability. In this embodiment, it is more preferable that the ink layer 22 does not have alkali releasability. The ink layer 22 may consist of only the ink cured product 22a, or may include a colorant such as a filler or a pigment or dye in addition to the ink cured product 22a.

[0029] The actinic radiation curable inkjet ink for forming the ink layer has the same structure as the actinic radiation curable inkjet ink exemplified as a preferred embodiment of the composition for forming the primer layer, except that it contains a colorant. Examples of the colorant include dyes and pigments. From the viewpoint of durability such as heat resistance, light resistance, and water resistance, the colorant is preferably a pigment. As the pigment, any of organic pigments and inorganic pigments that are usually commercially available can be used. Examples of the pigment include the pigments described in "Dictionary of Pigments" edited by Seijiro Ito (published in 2000), "Industrial Organic Pigments" by W. Herbst and K. Hunger, JP-A No. 2002-12607, JP-A No. 2002-188025, JP-A No. 2003-26978, and JP-A No. 2003-342503. The color of the colorant may be any color, such as black, white, blue, red, green, yellow, orange, etc., and is not particularly limited, but when printing the information image portion of the identification code portion, it is preferable that the colorant be black, blue, or green. Also, when printing the background printing portion 22B, it is preferable that the colorant be white, red, yellow, or orange. The black pigment is, for example, carbon black. The white pigment is, for example, titanium dioxide.

[0030] The entire ink cured product 22a is located on the primer cured product 21a. This eliminates any portion where the ink layer 22 is in direct contact with the outer surface of the body 12, ensuring alkali peelability over the entire area including the center of the printed part 20. The primer cured product 21a is preferably in the form of a continuous film that does not have pinholes through which the ink cured product 22a can penetrate. Such a continuous film-like primer cured product 21a can be formed during the manufacture of the printed part 20 by leveling after the active energy ray-curable inkjet ink for forming the primer layer is applied to the body 12 and before irradiation with active energy rays.

[0031] The ink amount regulating printed portion 20A integrally includes a contour overlapping portion 31 and / or a contour adjacent portion 32. As shown in FIG. 2 and FIG. 3, the contour overlapping portion 31 is a portion where the shortest distance between a first contour p1, which is the contour of the printed region of the primer layer 21, and a second contour p2, which is the contour of the printed region of the ink layer 22, is 0 mm. The contour overlapping portion 31 is a portion where the shortest distance t1 between the first contour and the second contour is 0 mm, as shown at the left end of FIG. 3, for example, and can also be said to be a portion where the first contour p1 and the second contour p2 overlap. The contour adjacent portion 32 is a portion where the first contour p1, which is the contour of the printed region of the primer layer 21, is outside the second contour p2, which is the contour of the printed region of the ink layer 22, and where the shortest distance between the contour (first contour) p1 of the printed region of the primer layer 21 and the contour (second contour) p2 of the printed region of the ink layer 22 is in a range of more than 0 mm and 2 mm or less. The contour adjacent portion 32 is a portion where the shortest distance t2 between the first contour and the second contour exceeds 0 mm and is 2 mm or less, as shown at the right end in FIG. 3, for example. The ink amount regulating printed portion 20A may have only the contour overlapping portion 31, only the contour adjacent portion 32, or both the contour overlapping portion 31 and the contour adjacent portion 32. The ink amount regulating printed portion 20A may further include a contour remote portion 33 integrally in addition to the contour overlapping portion 31 and / or the contour adjacent portion 32. The contour remote portion 33 is a portion where the first contour p1 is outside the second contour p2 and where the shortest distance between the first contour p1 and the second contour p2 exceeds 2 mm. The contour remote portion 33 is a portion where the shortest distance t3 between the first contour p1 and the second contour p2 exceeds 2 mm, for example, in FIG. 2. In this specification, the shortest distance between the first contour p1 and the second contour p2 refers to the shortest length from an arbitrary point on the first contour p1 to the second contour p2 as a reference point. If there is a reference point where this shortest length is 0 mm or is in the range of more than 0 mm but not more than 2 mm, the printing unit 20 is the ink amount regulating printing unit 20A.In the case where the ink layer 22 is composed of a plurality of separated segments, such as a one-dimensional code including a group of bars or a two-dimensional code including a group of cells as shown in FIG. 1, a character string such as product information, or a design with small images scattered in adjacent positions, and the distance between adjacent segments is 2 mm or less, in this embodiment, the printing area of ​​the ink layer 22 is an area that covers the plurality of segments, and the second contour p2 is the contour of the area that covers the plurality of segments. For example, when the ink layer 22 shows a character string such as product information, the printing area of ​​the ink layer 22 is an area that includes the entire character string, and the second contour p2 is the outer contour of the character string among the contours of the characters located at the outermost position of the character string. Alternatively, when the ink layer 22 shows a character string such as product information, the printing area of ​​the ink layer 22 is an area within an encircling line that surrounds the entire character string, and the second contour p2 is the contour of the encircling line. The encircling line is a straight line, a curved line, or a combination thereof that passes through the outer contour of the character string among the contours of the characters located at the outermost position of the character string. Furthermore, when the ink layer 22 shows a character string such as product information and the vicinity of the character string is surrounded by a frame line, the printing area of ​​the ink layer 22 is the area inside the frame line including the frame line, and the second contour p2 is the contour of the frame line. In this embodiment, in the ink amount regulation printing unit 20A, it is preferable that the first contour p1 has a shape that follows the second contour p2, and it is more preferable that the first contour p1 has a shape that follows the second contour p2 at a distance of more than 0 mm and not more than 2 mm all around.

[0032] FIG. 4 is a diagram showing a schematic enlargement of a part of the print part near the contour. In FIG. 4, for the convenience of explanation, the ink cured product 22a of the ink layer 22 is shown as a blank circle, and the ideal outline L2 of the ink layer 22 based on image data is shown as a broken line. In addition, in FIG. 4, the primer cured product 21a of the primer layer 21 is omitted, and only the ideal outline L1 of the primer layer 21 based on image data is shown. In the inkjet recording method, a printed matter is formed by minute ink droplets discharged from an inkjet print head landing on a printed matter and curing. Therefore, as shown in FIG. 4, each ink cured product 22a is in the form of a dot formed by the curing of the minute ink droplets, and the ink layer 22 is formed as a cured film in which the dot-shaped ink cured products 22a are collected. The outline (second outline) p2 of the ink layer 22 has minute unevenness due to dots when observed under magnification with a magnifying glass or a digital microscope, but the size of each ink cured product 22a is so small that the human eye cannot distinguish the dots, and the outline of the printed area of ​​the ink layer 22 when visually observed (hereinafter, the outline when visually observed may be referred to as the visual outline) generally coincides with the ideal outline L2. Note that although the primer cured products 21a are not shown in FIG. 4, each of the primer cured products 21a also has a dot shape like the ink cured products 22a, and the primer layer 21 is formed as a cured film in which the dot-shaped primer cured products 21a are gathered. The visual outline of the printed area of ​​the primer layer 21 generally coincides with the ideal outline L1. In this embodiment, the outline (first outline) p1 of the printed area of ​​the primer layer 21 is the visual outline of the printed area of ​​the primer layer 21, and the outline (second outline) p2 of the printed area of ​​the ink layer 22 is the visual outline of the printed area of ​​the ink layer 22. The contour (first contour) p1 of the printed area of ​​the primer layer 21 and the contour (second contour) p2 of the printed area of ​​the ink layer 22 can be regarded as ideal outlines L1 and L2 based on image data, respectively.

[0033] In the inkjet recording method, when the flight trajectory of minute ink droplets discharged from an inkjet print head is affected by air currents or the like and causes a deviation in the landing position on a printed material, some of the multiple ink cured products 22a may land outside the printing area P beyond the ideal outline L2, as in the ink cured product 22a designated by reference numeral 22a1 in Fig. 4. In this embodiment, taking into consideration the range of such landing deviation, attention is paid to the distance between the contour (first contour) p1 of the printing area of ​​the primer layer 21 and the contour (second contour) p2 of the printing area of ​​the ink layer 22, and it has been found that the ink usage amount of the primer layer 21 can be minimized by setting the shortest distance between the contour (first contour) p1 of the printing area of ​​the primer layer 21 and the contour (second contour) p2 of the printing area of ​​the ink layer 22 in the contour adjacent portion 32 to a range of more than 0 mm and 2 mm or less, thereby completing the present invention. The shortest distance between the contour (first contour) p1 of the printed region of the primer layer 21 and the contour (second contour) p2 of the printed region of the ink layer 22 in the contour vicinity portion 32 is preferably 0.2 to 1.0 mm.

[0034] In this embodiment, it is preferable that at least a part of the ink amount regulating printed section 20A is a contour adjacent section 32 rather than a configuration in which the entire circumference of the ink amount regulating printed section 20A is a contour overlapping section 31, and it is preferable that the entire circumference of the ink amount regulating printed section 20A is a contour adjacent section 32 as shown in Fig. 5. The presence of the contour adjacent section 32 prevents the ink layer 22 from protruding from the primer layer 21 even if there is a landing deviation of the ink in the ink layer 22, and it is possible to minimize the amount of ink used in the primer layer 21 while ensuring recyclability.

[0035] In this embodiment, the number of the printing section 20 is not particularly limited, and may be one as shown in FIG. 1, or may be two or more as shown in FIG. 7. Here, the number of the printing section 20 is the number of printing areas of the primer layer 21. For example, when the ink layer 22 is composed of a plurality of separated segments, such as a one-dimensional code including a group of bars or a two-dimensional code including a group of cells as shown in FIG. 1, a character string such as product information, or a design including small images scattered in adjacent positions, a separate primer layer 21 may be provided for each segment of the ink layer 22, or the primer layer 21 may be provided collectively so as to cover the plurality of segments of the ink layer 22. When the interval between adjacent segments is 2 mm or less, it is preferable that the primer layer 21 is provided collectively so as to cover the plurality of segments of the ink layer 22. In this embodiment, when there are two or more printing sections 20, the printing section 20 may include other printing sections in addition to the ink amount regulation printing section 20A. The other printed portion is, for example, a printed portion 20B (sometimes called a non-ink amount regulated printed portion or a normal printed portion) that does not have a contour overlap portion 31 or a contour adjacent portion 32, and has only a contour remote portion 33 in which the shortest distance between the contour (first contour) p1 of the printed area of ​​the primer layer 21 and the contour (second contour) p2 of the printed area of ​​the ink layer 22 exceeds 2 mm.

[0036] In the plastic container 1 according to this embodiment, it is preferable that all of the printed portions 20 are the ink amount regulating printed portions 20A, which can further improve the recyclability and productivity.

[0037] In the plastic container 1 according to this embodiment, the total area of ​​the printed region of the ink layer 22 in all of the printed parts 20 is preferably 50 to 95%, and more preferably 55 to 90%, of the total area of ​​the printed region of the primer layer 21 in all of the printed parts 20. This can further improve recyclability and productivity.

[0038] The total amount of the dry ink adhesion of the printed part 20 is 2.5% by mass, preferably 2.4% by mass or less, more preferably 0.7% by mass or less, and even more preferably 0.6% by mass or less, based on the total mass of the container body 10 and the printed part 20. The lower limit of the total amount of the dry ink adhesion of the printed part 20 may be appropriately set according to the mass of the container body, and is not particularly limited, but is, for example, 0.17% by mass or more based on the total mass of the container body 10 and the printed part 20. The total amount of the dry ink adhesion of the printed part 20 is the sum of the dry mass of the primer layer 21 and the dry mass of the ink layer 22. For example, when there is only one printed part 20, it is the dry mass of the primer layer 21 and the dry mass of the ink layer 22 in the printed part 20. When there are two or more printed parts 20, it is the sum of the dry mass of the primer layer 21 and the dry mass of the ink layer 22 in each printed part 20. The total amount of the dry ink adhesion of the printed part 20 can be obtained, for example, as follows. The mass (mass W1) of the entire plastic container 1 is measured in advance, and the mass (mass W2) of the container body 10 is measured after at least the area including the printed part 20 of the plastic container 1 is immersed in an alkaline solution (for example, a 1.5% by mass sodium hydroxide aqueous solution at 85°C to 90°C) to peel off and remove the printed part 20 and dry it. The difference (W1-W2) between the mass W1 and the mass W2 is the total amount of dried ink attached to the printed part 20. The mass of the container body 10 is the mass of the container body 10 itself before the printed part 20 is provided, and is the mass W2. The total mass of the container body 10 and the printed part 20 is the mass of the container body 10 plus the total amount of dried ink attached to the printed part 20, and is the sum of the mass W1 and the mass W2 (W1+W2). By having the printing unit 20 with the ink amount regulating printing unit 20A as in this embodiment, the dry mass of the primer layer 21 can be reduced to the minimum necessary, thereby reducing the total amount of dried ink adhered to the entire plastic container 1.

[0039] An example of a method for forming the printed part 20 will be described. First, an active energy ray curable inkjet ink is ejected from an inkjet head as a composition for forming a primer layer and adhered to the outer surface of the body part 12. Thereafter, active energy rays are irradiated to form a cured film. This cured film is the primer layer 21. Next, an active energy ray curable inkjet ink is ejected from an inkjet head as a composition for forming an ink layer and adhered to the primer layer 21. Thereafter, active energy rays are irradiated to form a cured product. When the ink layer 22 is two or more layers, the ink is repeatedly applied and cured. The obtained cured product is the ink layer 22. The active energy rays are not particularly limited, and are, for example, gamma rays, beta rays, electron beams, ultraviolet rays, or visible rays. Of these, it is preferable that the active energy rays are ultraviolet rays. [Explanation of symbols]

[0040] 1. Plastic container 10 Container body 11 Mouth 12 Torso 12a Upper torso 12b Body 12c lower torso 20 Printing Department 20A Ink volume control printing unit 20B Non-ink quantity regulated printing section, normal printing section 21 Primer layer 21a Primer hardened material 22 Ink layer 22a Ink cured product 31 Contour overlap 32 Contour adjacent area L2 Ideal outline of the ink layer L1 Ideal outline of primer layer p1 Contour of the printing area of ​​the primer layer (first contour) p2 Contour of the printing area of ​​the ink layer (second contour) t1, t2, t3 Shortest distance between the first and second contours

Claims

1. a container body having a mouth and a body connected to the mouth; At least one printed portion including a primer layer having alkali releasability provided on the outer surface of the body and an ink layer provided on the primer layer; A plastic container comprising: the primer layer includes a primer cured product that is a cured product of an active energy ray-curable inkjet ink for forming a primer layer, the ink layer includes an ink cured product that is a cured product of an active energy ray-curable inkjet ink for forming the ink layer, and all of the cured ink is located on top of the cured primer, At least one of the printing units is an ink amount regulation printing unit, The ink amount regulating printed portion has a first contour of the printed area of ​​the primer layer and a second contour of the printed area of ​​the ink layer, and includes a contour overlap portion where the shortest distance between the first contour and the second contour is 0 mm, and / or a contour adjacent portion where the first contour is outside the second contour and the shortest distance between the first contour and the second contour is in the range of more than 0 mm and not more than 2 mm.

2. 2. The plastic container according to claim 1, wherein the entirety of the printed portion is the ink amount regulation printed portion.

3. The plastic container according to claim 1 or 2, characterized in that the total area of ​​the printed area of ​​the ink layer in all of the printed parts is 50 to 95% of the total area of ​​the printed area of ​​the primer layer in all of the printed parts.

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