Recording method and packaging method

Abstract

To provide a recording method not requiring a jig to be set each time according to the size and shape of a container and a shrink film.SOLUTION: A recording method for recording on a shrink film with radiation-curable inks. The recording method includes forming an image on the shrink film with a first radiation-curable ink by an inkjet method, and forming a fixing pattern by applying a second radiation-curable ink to a surface of the shrink film that is to come into contact with an object to be wrapped.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a recording method and a packaging method. [Background technology]

[0002] In the packaging of beverages, food products, condiments, cosmetics, and other goods, films are frequently used to cover containers made of materials such as resin or glass. These films are attached to the container by shrinking, creating a tight, airtight seal, and are also known as shrinkable films (or shrink film). Shrink film is often printed with designs specific to the product, and this printing is typically done before the film is attached to the container, i.e., before it shrinks.

[0003] For example, Patent Document 1 discloses a method of performing inkjet printing on a heat-shrinkable film using a radiation-curable ink containing a colorant, a radical polymerizable compound, a polymerization initiator, etc., and then curing the ink by irradiation with ultraviolet light or other radiation. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2003-285540 [Overview of the project] [Problems that the invention aims to solve]

[0005] The shrink film is applied to containers and other packaging objects by positioning the shrink film around the packaging object and then shrinking it to conform to the shape of the container's outer circumference through heating or other means. During this shrinking process, jigs or other tools may be used to align the shrink film and the packaging object to prevent misalignment.

[0006] On the other hand, printing on shrink film using radiation-curing inkjet inks has a need for printing shrink film for small batches of diverse product containers. In this case, it was necessary to set up jigs for each product type to match the size and shape of the container and shrink film. Furthermore, during shrinkage, it was time-consuming to adjust the positioning of the container, shrink film, and jigs. [Means for solving the problem]

[0007] One aspect of the recording method according to the present invention is: A recording method that uses radiation-curing ink to record on shrink film, The process involves forming an image on the shrink film using a first radiation-curing ink by an inkjet method, The process involves applying a second radiation-curing ink to the surface of the shrink film that comes into contact with the packaged object to form a fixing pattern. Includes.

[0008] One aspect of the packaging method according to the present invention is: This includes packaging the object to be packaged using the shrink film recorded by the recording method described above. [Brief explanation of the drawing]

[0009] [Figure 1] A perspective view showing an example of a serial inkjet printer. [Figure 2] A schematic diagram of an example in which an image using a first radiation-curable ink and a fixing pattern using a second radiation-curable ink are formed on shrink film. [Figure 3] A schematic diagram showing a packaged item with shrink film applied, viewed from the side. [Figure 4] A schematic diagram showing the shrink film placed on the packaged object, viewed from above. [Figure 5] A schematic diagram showing an example of the arrangement of fixing patterns. [Figure 6] A schematic diagram showing an example of the arrangement of fixing patterns. [Figure 7] Schematic diagram showing an example of the arrangement of the fixing pattern. [Figure 8] Schematic diagram showing a side view of the state where the shrink film of the conventional example is arranged on the object to be packaged. [Figure 9] Schematic diagram showing the dimensions of the sample used in the example.

Mode for Carrying Out the Invention

[0010] Hereinafter, embodiments of the present invention will be described. The embodiments described below illustrate examples of the present invention. The present invention is not limited to the following embodiments, and also includes various modified forms implemented within the scope of not changing the gist of the present invention. Note that not all of the configurations described below are essential configurations of the present invention.

[0011] 1. Recording method The recording method according to the present embodiment is a recording method in which recording is performed on a shrink film with a radiation-curable ink, and includes a step of forming an image on the shrink film by an inkjet method using a first radiation-curable ink, and a step of attaching a second radiation-curable ink to the surface of the shrink film on the side in contact with the object to be packaged to form a fixing pattern.

[0012] 1.1. Shrink film and object to be packaged The shrink film is not particularly limited. For example, a film having a property of shrinking by 10% or more in at least one direction when heated to 80°C is used. It is more preferable that the shrink film shrinks by 15% or more, further preferably by 20% or more, and particularly preferably by 30% or more. The temperature for heating for the shrinkage of the shrink film is not particularly limited.

[0013] The shrinkage rate when shrink film is heated can be calculated using the following formula. The shrinkage rate can be measured in any direction, and in this embodiment, it is sufficient that the shrinkage rate in at least one direction where the most shrinkage occurs is within the above range. A stretched film, in which an unstretched film is stretched and the resin is oriented in the stretching direction, has the property that when heated, the stress based on molecular orientation is relieved and it shrinks to the dimensions before stretching. The shrinkage rate and its direction can be adjusted, for example, by the stretching process when manufacturing the shrink film, and the shrinkage direction is not particularly limited and may be in the mechanical direction, the width direction, or both. Shrinkage rate (%) = (Length before shrinkage - Length after shrinkage) / Length before shrinkage

[0014] The resin that makes up the shrink film is not particularly limited, but examples include polyolefin resins, polyester resins, polystyrene resins, and polyvinyl chloride resins. As an example, a polyester resin that makes up the shrink film is obtained by condensation polymerization of a dicarboxylic acid component and a polyhydric alcohol component.

[0015] The dicarboxylic acid component is not particularly limited, but examples include aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, naphthalene-1,4- or -2,6-dicarboxylic acid, and 5-sodium sulfisoisophthalic acid; ester-forming derivatives of aromatic dicarboxylic acids such as dialkyl esters and diaryl esters; or aliphatic dicarboxylic acids such as dimer acid, glutaric acid, adipic acid, sebacic acid, azelaic acid, oxalic acid, and succinic acid.

[0016] In addition, oxycarboxylic acids such as p-oxybenzoic acid, and polyvalent carboxylic acids such as trimellitic anhydride and pyromellitic anhydride may also be used.

[0017] The polyhydric alcohol component is not particularly limited, but examples include alkylene glycols such as ethylene glycol, diethylene glycol, dimergol, propylene glycol, triethylene glycol, 1,4-butanediol, neopentyl glycol, 1,3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 2-methyl-1,5-pentanediol, 2,2-diethyl-1,3-propanediol, 1,9-nonanediol, and 1,10-decanediol, ethylene oxide adducts of bisphenol compounds or their derivatives, trimethylolpropane, glycerin, pentaerythritol, polyoxytetramethylene glycol, and polyethylene glycol.

[0018] In addition, polyhydric alcohols such as limethylolpropane, trimethylolethane, glycerin, diglycerin, and pentaerythritol may also be used.

[0019] Furthermore, while there are no particular limitations on the polystyrene-based resins, examples include polystyrene, poly(p-, m- or o-methylstyrene), poly(2,4-, 2,5-, 3,4- or 3,5-dimethylstyrene), poly(p-tert-butylstyrene), and other poly(alkylstyrenes), poly(p-, m- or o-chlorostyrene), poly(p-, m- or o-bromostyrene), poly(p-, m- or o-fluorostyrene), poly(o-methyl-p-fluorostyrene), and other poly(halogenated styrenes). Examples include poly(halogen-substituted alkylstyrenes) such as methylstyrene, poly(p-, m- or o-methoxystyrene), poly(alkoxystyrenes) such as poly(p-, m- or o-ethoxystyrene), poly(carboxyalkylstyrenes) such as poly(p-, m- or o-carboxymethylstyrene), poly(alkyl ether styrenes) such as poly(p-vinyl benzyl propyl ether), poly(alkylsilyl styrenes) such as poly(p-trimethylsilyl styrene), and poly(vinyl benzyl dimethoxy phosphate).

[0020] The shrink film may contain a rubber component. Such rubber components are not particularly limited, but examples include rubber in which the butadiene portion of a styrene-butadiene block copolymer is partially or completely hydrogenated, styrene-butadiene copolymer rubber, styrene-isoprene block copolymer, rubber in which the butadiene portion of a styrene-isoprene block copolymer is partially or completely hydrogenated, methyl acrylate-butadiene-styrene copolymer rubber, methyl methacrylate-alkyl acrylate-butadiene-styrene copolymer rubber, and the like.

[0021] The shrink film is preferably a stretched film. The stretching process may be either uniaxial stretching or biaxial stretching. The stretching method is not particularly limited, but for example, one method may include a stretching step in which the unstretched film is stretched by 2.0 to 8.0 times, preferably 2.5 to 6.0 times, in the direction that gives it shrinkability, within a temperature range of Tg-20°C to Tg+40°C based on the glass transition temperature (Tg) of the resin constituting the shrink film. After the stretching step, heat treatment may be performed at a temperature of 50 to 110°C while stretching by 0 to 15% or relaxing by 0 to 15%.

[0022] The objects to be wrapped in shrink film are not limited, but include containers made of resin or glass, such as PET bottles, polyolefin bottles, and glass bottles. The objects to be wrapped may be a single object or multiple objects. If there are multiple objects to be wrapped, they may be bundled together with shrink film. The shape of the objects to be wrapped is also not limited.

[0023] 1.2. Image Formation Process In this process, an image is formed on the shrink film before shrinkage using an inkjet method with a first radiation-curing ink.

[0024] 1.2.1. First type of radiation-curable ink The first radiation-curable ink hardens when exposed to radiation. Examples of radiation include ultraviolet light, electron beams, infrared light, visible light, and X-rays. Ultraviolet light is preferred because radiation sources are readily available and widely used, and materials suitable for curing by ultraviolet radiation are readily available and widely used.

[0025] The components included in the first radiation-curable ink are not particularly limited, but examples include polymerizable compounds, polymerization initiators, polymerization inhibitors, sensitizers, surfactants, colorants, and dispersants. The first radiation-curable ink does not need to contain all of these components; it may contain only some of them. The components that may be included in the first radiation-curable ink are described below.

[0026] (1) Polymerizable compound Substances containing polymerizable functional groups are collectively called polymerizable compounds. Polymerizable compounds may include monofunctional monomers having one polymerizable functional group and polyfunctional monomers having multiple polymerizable functional groups. Polymerizable compounds may be used individually or in combination of two or more types.

[0027] The weighted average of the glass transition temperatures of the polymerizable compounds contained in the first radiation-curable ink is 20 to 70°C, preferably 25 to 65°C, more preferably 30 to 60°C, and even more preferably 40 to 50°C. A weighted average of 20°C or higher for the glass transition temperature further improves blocking resistance. Furthermore, a weighted average of 20°C or higher for the glass transition temperature tends to further improve curability. Moreover, a weighted average of 70°C or lower for the glass transition temperature further improves shrinkage properties (resistance to cracking and color unevenness due to shrinkage of the ink-cured coating).

[0028] The "glass transition temperature of the polymerizable compound" means the glass transition temperature of the homopolymer of the polymerizable compound. Further, the weighted average of the glass transition temperature of the polymerizable compound can be adjusted according to the glass transition temperature of the homopolymer of the polymerizable compound used and the mass ratio of the polymerizable compound used.

[0029] Here, the calculation method of the weighted average of the glass transition temperature of the homopolymer in the polymerizable compound will be described. Let the value of the weighted average of the glass transition temperature of the homopolymer be Tg All The glass transition temperature of the homopolymer of each polymerizable compound is Tg N The mass ratio of the polymerizable compound is X N (wt%). N is numbered sequentially from 1 according to the type of polymerizable compound contained in the first radiation-curable ink. For example, when three types of polymerizable compounds are used, Tg1, Tg2, and Tg3 occur. The weighted average Tg All of the glass transition temperature of the homopolymer is the sum of the products of the glass transition temperature Tg N of the homopolymer calculated by each polymerizable compound and the mass ratio X N . Therefore, the following formula (1) holds. Tg All =Σ(Tg N ×X N ) ···(1)

[0030] Also, the measurement method of the glass transition temperature of the homopolymer of the polymerizable compound can be carried out by differential scanning calorimetry (DSC) in accordance with JIS K7121. As the measuring device, for example, the type "DSC6220" manufactured by Seiko Instruments Inc. can be used, and as the sample, a monomer polymerized to such an extent that the glass transition temperature of its homopolymer becomes constant can be used.

[0031] The polymerizable compound content is preferably 55% to 85% by mass, more preferably 60% to 80% by mass, and even more preferably 65% ​​to 75% by mass, relative to the total amount of the first radiation-curable ink. When the polymerizable compound content is within the above range, blocking resistance, shrink properties, or curability tend to be improved.

[0032] (1-1) Monofunctional monomers The monofunctional monomers are not particularly limited, but examples include nitrogen-containing monofunctional monomers, aromatic group-containing monofunctional monomers, and monofunctional monomers having an alicyclic structure. In addition, other monofunctional monomers may be included as needed, either in place of or in addition to these.

[0033] The monofunctional monomer content is preferably 30% by mass or more, and more preferably 40% by mass or more, relative to the total amount of polymerizable compounds. A monofunctional monomer content of 30% by mass or more tends to further improve blocking resistance.

[0034] The following are examples of monofunctional monomers, but are not limited to these.

[0035] (1-1-1) Nitrogen-containing monofunctional monomers The polymerizable compound preferably contains a nitrogen-containing monofunctional monomer. This tends to improve the adhesion and blocking resistance of the resulting coating film.

[0036] Examples of nitrogen-containing monofunctional monomers include nitrogen-containing monofunctional vinyl monomers such as N-vinylcaprolactam (n-VC), N-vinylformamide, N-vinylcarbazole, N-vinylacetamide, vinylmethyloxazolidinone (VMOX), and N-vinylpyrrolidone; nitrogen-containing monofunctional acrylate monomers such as acryloylmorpholine (ACMO); and nitrogen-containing monofunctional acrylamide monomers such as (meth)acrylamide, N-hydroxymethyl(meth)acrylamide, diacetoneacrylamide, N,N-dimethyl(meth)acrylamide, and dimethylaminoethyl acrylate benzyl chloride quaternary salt.

[0037] Among these, it is preferable to include either a nitrogen-containing monofunctional vinyl monomer or a nitrogen-containing monofunctional acrylate monomer, more preferably a monomer having a nitrogen-containing heterocyclic structure such as vinylmethyloxazolidinone, acryloylmorpholine, or N-vinylcaprolactam, and even more preferably vinylmethyloxazolidinone. Including such a nitrogen-containing monofunctional monomer tends to further reduce the viscosity of the ink composition, thereby improving the discharge stability. Furthermore, including such a nitrogen-containing monofunctional monomer tends to further improve blocking resistance, shrink properties, or curability. Moreover, since vinylmethyloxazolidinone is a monomer with low viscosity at room temperature, including vinylmethyloxazolidinone tends to further improve the discharge stability.

[0038] The nitrogen-containing monofunctional monomer content is preferably 15% to 45% by mass, more preferably 20% to 40% by mass, and even more preferably 25% to 35% by mass, relative to the total amount of the first radiation-curable ink. When the nitrogen-containing monofunctional monomer content is within the above range, blocking resistance, shrinkage properties, or curability tend to be further improved.

[0039] (1-1-2) Aromatic group-containing monofunctional monomers The aromatic group-containing monofunctional monomers are not particularly limited, but examples include phenoxyethyl (meth)acrylate (PEA), benzyl (meth)acrylate, alkoxylated 2-phenoxyethyl (meth)acrylate, ethoxylated nonylphenyl (meth)acrylate, alkoxylated nonylphenyl (meth)acrylate, p-cumylphenol EO-modified (meth)acrylate, and 2-hydroxy-3-phenoxypropyl (meth)acrylate.

[0040] Among these, phenoxyethyl (meth)acrylate and benzyl (meth)acrylate are preferred, phenoxyethyl (meth)acrylate is more preferred, and phenoxyethyl acrylate (PEA) is even more preferred. By using such aromatic group-containing monofunctional monomers, the solubility of the polymerization initiator tends to be further improved, and the curability of the ink composition tends to be further improved. In particular, solubility tends to be good when using acyl phosphine oxide-based polymerization initiators or thioxanthone-based polymerization initiators.

[0041] The content of aromatic group-containing monofunctional monomers is preferably 25% to 55% by mass, more preferably 30% to 50% by mass, and even more preferably 35% to 45% by mass, relative to the total amount of the first radiation-curable ink. When the content of aromatic group-containing monofunctional monomers is within the above range, blocking resistance, shrink properties, or curability tend to be further improved.

[0042] (1-1-3) Monofunctional monomers having an alicyclic structure Monofunctional monomers having an alicyclic structure are not particularly limited, but examples include monomers having monocyclic hydrocarbon groups such as tert-butylcyclohexanol (meth)acrylate (TBCHA), 3,3,5-trimethylcyclohexyl (meth)acrylate (TMCHA), and 2-(meth)acrylic acid-1,4-dioxaspiro[4,5]decy-2-ylmethyl; monomers having unsaturated polycyclic hydrocarbon groups such as dicyclopentenyl (meth)acrylate and dicyclopentenyloxyethyl (meth)acrylate; and monomers having saturated polycyclic hydrocarbon groups such as dicyclopentanyl (meth)acrylate and isobornyl (meth)acrylate (IBXA).

[0043] Among these, isobornyl (meth)acrylate, tert-butylcyclohexanol acrylate, and trimethylcyclohexyl (meth)acrylate are preferred, with isobornyl acrylate being more preferred. Using monofunctional monomers having such alicyclic structures tends to improve blocking resistance, shrink properties, or curability.

[0044] Furthermore, the content of monofunctional monomers having an alicyclic structure is preferably 15% to 45% by mass, more preferably 20% to 40% by mass, and even more preferably 25% to 35% by mass, relative to the total amount of the first radiation-curable ink. When the content of monofunctional monomers having an alicyclic structure is within the above range, blocking resistance, shrink properties, or curability tend to be further improved.

[0045] (1-2) Polyfunctional monomers The polyfunctional monomer is not particularly limited, but examples include vinyl group-containing (meth)acrylates and polyfunctional (meth)acrylates. However, the polyfunctional monomer is not limited to these, and multiple types may be used.

[0046] The polyfunctional monomer content in the first radiation-curable ink is preferably 40% by mass or more, more preferably 50% by mass or more, and even more preferably 60% by mass, relative to the total amount of polymerizable compounds. This range of polyfunctional monomer content further improves blocking resistance. Examples of polyfunctional monomers are given below, but the invention is not limited to these.

[0047] (1-2-1) Vinyl group-containing (meth)acrylate The vinyl group-containing (meth)acrylate is not particularly limited, but examples include compounds represented by the following formula (I). Including such a vinyl group-containing (meth)acrylate tends to improve blocking resistance, shrink properties, or curability. H2C=CR 1 -CO-OR 2 -O-CH=CH-R 3 ... (I) (In the formula, R 1 R is a hydrogen atom or a methyl group, 2 R is a divalent organic residue with 2 to 20 carbon atoms. 3 (This refers to a hydrogen atom or a monovalent organic residue with 1 to 11 carbon atoms.)

[0048] In the above equation (I), R 2 Examples of divalent organic residues having 2 to 20 carbon atoms represented by include linear, branched, or cyclic alkylene groups having 2 to 20 carbon atoms, optionally substituted; alkylene groups having 2 to 20 carbon atoms, optionally substituted; and divalent aromatic groups having 6 to 11 carbon atoms, optionally substituted. Among these, alkylene groups having 2 to 6 carbon atoms, such as ethylene, n-propylene, isopropylene, and butylene groups, and alkylene groups having 2 to 9 carbon atoms, such as oxyethylene, oxy-n-propylene, oxyisopropylene, and oxybutylene groups, which have oxygen atoms in their structure due to ether bonds, are preferred. Furthermore, from the viewpoint of further reducing the viscosity of the ink composition and further improving the curability of the ink composition, R2 However, compounds having glycol ether chains in which an alkylene group having 2 to 9 carbon atoms and containing an oxygen atom via an ether bond in the structure of an oxyethylene group, oxy-n-propylene group, oxyisopropylene group, or oxybutylene group is more preferred.

[0049] In the above equation (I), R 3 As monovalent organic residues having 1 to 11 carbon atoms, linear, branched, or cyclic alkyl groups having 1 to 11 carbon atoms, which may be substituted, and aromatic groups having 6 to 11 carbon atoms, which may be substituted, are preferred. Among these, alkyl groups having 1 to 2 carbon atoms, such as methyl or ethyl groups, and aromatic groups having 6 to 8 carbon atoms, such as phenyl and benzyl groups, are even more preferred.

[0050] If any of the above organic residues are groups that may be substituted, the substituents can be divided into groups containing carbon atoms and groups that do not contain carbon atoms. First, if the substituent is a group containing carbon atoms, that carbon atom is counted in the number of carbon atoms of the organic residue. Examples of groups containing carbon atoms include, but are not limited to, carboxyl groups and alkoxy groups. Next, examples of groups that do not contain carbon atoms include, but are not limited to, hydroxyl groups and halo groups.

[0051] Specific examples of compounds of formula (I) are not particularly limited, but include, for example, 2-vinyloxyethyl (meth)acrylate, 3-vinyloxypropyl (meth)acrylate, 1-methyl-2-vinyloxyethyl (meth)acrylate, 2-vinyloxypropyl (meth)acrylate, 4-vinyloxybutyl (meth)acrylate, 1-methyl-3-vinyloxypropyl (meth)acrylate, 1-vinyloxymethylpropyl (meth)acrylate, 2-methyl-3-vinyloxypropyl (meth)acrylate, and 1,1-dimethyl-2-vinyloxypropyl (meth)acrylate. Cyethyl, 3-vinyloxybutyl (meth)acrylate, 1-methyl-2-vinyloxypropyl (meth)acrylate, 2-vinyloxybutyl (meth)acrylate, 4-vinyloxycyclohexyl (meth)acrylate, 6-vinyloxyhexyl (meth)acrylate, 4-vinyloxymethylcyclohexylmethyl (meth)acrylate, 3-vinyloxymethylcyclohexylmethyl (meth)acrylate, 2-vinyloxymethylcyclohexylmethyl (meth)acrylate, p-vinyloxymethylphenylmethyl (meth)acrylate, (meth)acrylic acid m-vinyloxymethylphenylmethyl methacrylate, o-vinyloxymethylphenylmethyl methacrylate, 2-(2-vinyloxyethoxy)ethyl methacrylate, 2-(2-vinyloxyethoxy)ethyl acrylate (VEEA), 2-(vinyloxyisopropoxy)ethyl methacrylate, 2-(vinyloxyethoxy)propyl methacrylate, 2-(vinyloxyethoxy)isopropyl methacrylate, 2-(vinyloxyisopropoxy)propyl methacrylate, 2-(vinyloxyisopropyl) methacrylate (Poxy)isopropyl, (meth)acrylate 2-(vinyloxyethoxyethoxy)ethyl, (meth)acrylate 2-(vinyloxyethoxyisopropoxy)ethyl, (meth)acrylate 2-(vinyloxyisopropoxyethoxy)ethyl, (meth)acrylate 2-(vinyloxyisopropoxyisopropoxy)ethyl, (meth)acrylate 2-(vinyloxyethoxyethoxy)propyl, (meth)acrylate 2-(vinyloxyethoxyisopropoxy)propyl, (meth)acrylate 2-(vinyloxyisopropoxyethoxy)propyl,(meth)acrylate 2-(vinyloxyisopropoxyisopropoxy)propyl, (meth)acrylate 2-(vinyloxyethoxyethoxy)isopropyl, (meth)acrylate 2-(vinyloxyethoxyisopropoxy)isopropyl, (meth)acrylate 2-(vinyloxyisopropoxyethoxy)isopropyl, (meth)acrylate 2-(vinyloxyisopropoxyisopropoxy)isopropyl, (meth)acrylate 2-(vinyloxyethoxyethoxyethoxy)ethyl, (meth)acrylate 2-(vinyloxy Examples include ethyl thylene(2-vinyloxyethoxy)ethyl acrylate, 2-(isopropenoxyethoxy)ethyl meth)acrylate, 2-(isopropenoxyethoxyethoxy)ethyl meth)acrylate, 2-(isopropenoxyethoxyethoxyethoxy)ethyl meth)acrylate, 2-(isopropenoxyethoxyethoxyethoxy)ethyl meth)acrylate, polyethylene glycol monovinyl ether meth)acrylate, and polypropylene glycol monovinyl ether meth)acrylate. Among these specific examples, 2-(2-vinyloxyethoxy)ethyl acrylate is particularly preferred because it allows for a good balance between the curability and viscosity of the first radiation-curable ink. In this embodiment, 2-(2-vinyloxyethoxy)ethyl acrylate may also be referred to as VEEA.

[0052] The content of vinyl group-containing (meth)acrylate is preferably 1.0% to 10% by mass, more preferably 2.0% to 8.0% by mass, and even more preferably 4.0% to 6.0% by mass, relative to the total amount of the first radiation-curable ink. When the content of vinyl group-containing (meth)acrylate is within the above range, blocking resistance, shrinkage properties, or curability tend to be further improved.

[0053] (1-2-2) Polyfunctional (meth)acrylate The polyfunctional (meth)acrylate is not particularly limited, but examples include dipropylene glycol di(meth)acrylate (DPGDA), diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, dipropylene glycol dimethacrylate, tripropylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, dimethylol-tricyclodecane di(meth)acrylate, bisphenol A EO (ethylene oxide) adduct di(meth)acrylate, and bisphenol A PO (propylene Examples include difunctional (meth)acrylates such as phenyl oxide adduct di(meth)acrylate, hydroxypivalate neopentyl glycol di(meth)acrylate, and polytetramethylene glycol di(meth)acrylate; and polyfunctional (meth)acrylates with three or more functions, such as trimethylolpropane tri(meth)acrylate, EO-modified trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, glycerin propoxy tri(meth)acrylate, caprolactone-modified trimethylolpropane tri(meth)acrylate, pentaerythritol ethoxytetra(meth)acrylate, and caprolactam-modified dipentaerythritol hexa(meth)acrylate.

[0054] Among these, dipropylene glycol diacrylate (DPGDA) is more preferred. Using such a polyfunctional (meth)acrylate tends to improve curability and abrasion resistance, and further reduce viscosity.

[0055] The polyfunctional (meth)acrylate content is preferably 2.5% to 17.5% by mass, more preferably 5.0% to 15% by mass, and even more preferably 7.5% to 12.5% ​​by mass, relative to the total amount of the ink composition. When the polyfunctional (meth)acrylate content is within the above range, the curability tends to be further improved and the viscosity tends to be further reduced.

[0056] (2) Polymerization initiator The polymerization initiator is not particularly limited as long as it is a photopolymerization initiator that generates active species when irradiated with radiation, but known polymerization initiators such as acylphosphine oxide polymerization initiators, alkylphenone polymerization initiators, titanocene polymerization initiators, and thioxanthone polymerization initiators can be used. Among these, acylphosphine oxide polymerization initiators and thioxanthone polymerization initiators are preferred, and acylphosphine oxide polymerization initiators are more preferred. Using such polymerization initiators tends to further improve the curability of the first radiation-curable ink. The polymerization initiator may be used alone or in combination of two or more types.

[0057] The polymerization initiator content is preferably 2.5% to 17.5% by mass, more preferably 5% to 15% by mass, and even more preferably 7.5% to 12.5% ​​by mass, relative to the total amount of the first radiation-curable ink. When the polymerization initiator content is within the above range, the curability of the composition tends to improve.

[0058] Acylphosphine oxide polymerization initiators are not particularly limited, but examples include 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, and bis-(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine oxide.

[0059] Commercially available acylphosphine oxide polymerization initiators include, but are not limited to, Omnirad 819 (bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide), IRGACURE 1800 (a mixture of bis-(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine oxide and 1-hydroxy-cyclohexyl-phenyl ketone in a mass ratio of 25:75), Speedcure TPO (2,4,6-trimethylbenzoyldiphenylphosphine oxide), and others.

[0060] (3) Sensitizers The first radiation-curable ink may contain a sensitizer. The sensitizer is not particularly limited, but examples include thioxanthone compounds. The thioxanthone compounds are not particularly limited, but examples include thioxanthone, diethylthioxanthone, isopropylthioxanthone, and chlorothioxanthone.

[0061] Commercially available thioxanthone-based polymerization initiators include, but are not limited to, Speedcure DETX (2,4-diethylthioxanthen-9-one), Speedcure ITX (2-isopropylthioxanthone) (both manufactured by Lambson), and KAYACURE DETX-S (2,4-diethylthioxanthone) (manufactured by Nippon Kayaku Co., Ltd.).

[0062] If a sensitizer is included, its content is preferably 0.5% to 7.5% by mass, more preferably 1.5% to 5.0% by mass, and even more preferably 2.5% to 3.5% by mass, relative to the total amount of the first radiation-curable ink. The curability of the composition tends to improve when the sensitizer content is within the above range.

[0063] (4) Polymerization inhibitors The first radiation-curable ink may contain a polymerization inhibitor. Examples of polymerization inhibitors, but not limited to, include p-methoxyphenol, hydroquinone monomethyl ether (MEHQ), 4-hydroxy-2,2,6,6-tetramethylpiperidine-N-oxyl, hydroquinone, cresol, t-butylcatechol, 3,5-di-t-butyl-4-hydroxytoluene, 2,2'-methylenebis(4-methyl-6-t-butylphenol), 2,2'-methylenebis(4-ethyl-6-butylphenol), and 4,4'-thiobis(3-methyl-6-t-butylphenol), hindered amine compounds, 2,2,6,6-tetramethylpiperidinyl-1-oxyl, 2,2,6,6-tetramethyl-4-hydroxypiperidine-1-oxyl (LA-7RD), or derivatives of 2,2,6,6-tetramethylpiperidinyl-1-oxyl.

[0064] If a polymerization inhibitor is included, its content is preferably 0.1% to 0.7% by mass, and more preferably 0.2% to 0.5% by mass, relative to the total amount of the first radiation-curable ink. Having the polymerization inhibitor content within the above range tends to further improve the storage stability of the first radiation-curable ink.

[0065] (5) Surfactants The first radiation-curable ink may contain a surfactant. The surfactant is not particularly limited, but examples include acetylene glycol-based surfactants, fluorine-based surfactants, and silicone-based surfactants.

[0066] Examples of acetylene glycol-based surfactants include 2,4,7,9-tetramethyl-5-decine-4,7-diol and alkylene oxide adducts of 2,4,7,9-tetramethyl-5-decine-4,7-diol, as well as 2,4-dimethyl-5-decine-4-ol and alkylene oxide adducts of 2,4-dimethyl-5-decine-4-ol.

[0067] Examples of fluorinated surfactants include perfluoroalkyl sulfonates, perfluoroalkyl carboxylates, perfluoroalkyl phosphate esters, perfluoroalkyl ethylene oxide adducts, perfluoroalkyl betaines, and perfluoroalkylamine oxide compounds.

[0068] Examples of silicone-based surfactants include polysiloxane compounds, polyester-modified silicones, or polyether-modified organosiloxanes. Examples of polyester-modified silicones include BYK-347, 348, BYK-UV3500, 3510, and 3530 (all manufactured by BYK Additives & Instruments), while an example of a polyether-modified silicone is BYK-3570 (manufactured by BYK Additives & Instruments).

[0069] If a surfactant is included, its content is preferably 0.1% to 1.0% by mass, and more preferably 0.2% to 0.8% by mass, relative to the total mass of the first radiation-curable ink. When the surfactant content is within the above range, the wettability of the first radiation-curable ink tends to improve.

[0070] (6) Colorants The first radiation-curable ink may further contain a colorant. By containing a colorant, the first radiation-curable ink can be used as a colored ink. The colorant can be at least one of pigments and dyes. Examples of usable colorants are given below.

[0071] As inorganic pigments, carbon blacks (CI (Colour Index Generic Name) Pigment Black 7) such as furnace black, lamp black, acetylene black, and channel black, as well as iron oxide and titanium dioxide can be used.

[0072] Examples of organic pigments include azo pigments such as insoluble azo pigments, condensed azo pigments, azo lakes, and chelate azo pigments; polycyclic pigments such as phthalocyanine pigments, perylene and perinone pigments, anthraquinone pigments, quinacridone pigments, dioxane pigments, thioindigo pigments, isoindolinone pigments, and quinophthalone pigments; dye chelates (e.g., basic dye type chelates, acid dye type chelates, etc.); dye lakes (basic dye type lakes, acid dye type lakes); nitro pigments; nitroso pigments; aniline black; and daylight fluorescent pigments.

[0073] The total amount of colorant can be appropriately changed depending on the purpose, but is preferably 0.5% to 15% by mass, more preferably 1.0% to 10% by mass, and even more preferably 1.5% to 5.0% by mass, relative to the total amount of the first radiation-curable ink. The first radiation-curable ink may also be a clear ink that does not contain colorant, or contains colorant to an extent that is not intended for coloring (for example, 0.1% by mass or less).

[0074] The dyes are not particularly limited, but examples include acid dyes such as CI Acid Yellow, CI Acid Red, CI Acid Blue, CI Acid Orange, CI Acid Violet, and CI Acid Black; basic dyes such as CI Basic Yellow, CI Basic Red, CI Basic Blue, CI Basic Orange, CI Basic Violet, and CI Basic Black; direct dyes such as CI Direct Yellow, CI Direct Red, CI Direct Blue, CI Direct Orange, CI Direct Violet, and CI Direct Black; reactive dyes such as CI Reactive Yellow, CI Reactive Red, CI Reactive Blue, CI Reactive Orange, CI Reactive Violet, and CI Reactive Black; and disperse dyes such as CI Disperse Yellow, CI Disperse Red, CI Disperse Blue, CI Disperse Orange, CI Disperse Violet, and CI Disperse Black. The above dyes may be used individually or in combination of two or more.

[0075] (7) Other ingredients The first radiation-curable ink may further contain, if necessary, colorants such as pigments and dyes, and additives such as dispersants for pigments.

[0076] 1.2.2. Recording by inkjet method The process of forming an image with the first radiation-curable ink is carried out by an inkjet method. The inkjet method can be performed by applying the first radiation-curable ink to the apparatus exemplified below and using shrink film before shrinkage as the recording medium.

[0077] As an example of an inkjet device, Figure 1 shows a perspective view of a serial printer. As shown in Figure 1, the serial printer 20 comprises a transport unit 220 and a recording unit 230. The transport unit 220 transports the recording medium F fed into the serial printer to the recording unit 230 and discharges the recorded recording medium outside the serial printer. Specifically, the transport unit 220 has feed rollers and transports the fed recording medium F in the sub-scanning direction T1.

[0078] Furthermore, the recording unit 230 includes an inkjet head 231 that ejects a composition onto the recording medium F sent from the transport unit 220, a radiation source 232 that irradiates the attached ink composition with radiation, a carriage 234 on which these are mounted, and a carriage movement mechanism 235 that moves the carriage 234 in the main scanning directions S1 and S2 of the recording medium F.

[0079] In a serial printer, the inkjet head 231 is equipped with a head that is shorter than the width of the recording medium, and the head moves, performing recording in multiple passes (multipass). In a serial printer, the head 231 and radiation source 232 are mounted on a carriage 234 that moves in a predetermined direction, and the head moves along with the movement of the carriage, ejecting the composition onto the recording medium. This allows for recording in two or more passes (multipass). A pass is also called a main scan. A sub-scan is performed between passes to transport the recording medium. In other words, main scans and sub-scans are performed alternately.

[0080] Although Figure 1 shows a configuration in which the radiation source is mounted on a carriage, the system is not limited to this configuration, and the radiation source may be mounted on a carriage or not.

[0081] Furthermore, the inkjet device is not limited to the serial-type printer described above, but may also be a line-type printer.

[0082] 1.3. Process for forming a fixing pattern In this process, a second radiation-curing ink is applied to the side of the shrink film that comes into contact with the packaged object to form a fixing pattern. This process is performed on the shrink film before it shrinks.

[0083] The side of the shrink film that comes into contact with the packaged object may be the side on which the first radiation-curable ink is recorded, or it may be the reverse side. In other words, the fixing pattern is formed on the side of the shrink film that comes into contact with the packaged object, regardless of whether or not the first radiation-curable ink coating is present.

[0084] 1.3.1. Second type of radiation-curable ink The coating film of the second radiation-curable ink after curing has tackiness (adhesion) compared to the coating film of the first radiation-curable ink after curing. The second radiation-curable ink is the same as the first radiation-curable ink except that the amount of "(1-1) monofunctional monomer" among the "(1) polymerizable compounds" described above is greater than that of the first radiation-curable ink. Therefore, the same composition is explained in the section "1.2.1. First radiation-curable ink" above by substituting the first radiation-curable ink with the second radiation-curable ink.

[0085] In the second radiation-curable ink, the content of monofunctional monomers among the polymerizable compounds is preferably 50% by mass or more, more preferably 60% by mass or more, and even more preferably 65% ​​by mass or more. This content improves the tackiness (adhesion) of the coating film after curing of the second radiation-curable ink. As a result, the shrink film before shrinkage can be fixed to the packaged object by utilizing the tackiness of the coating film after curing of the second radiation-curable ink.

[0086] 1.3.2. Method of attachment The second radiation-curable ink may be applied to the shrink film by an inkjet method, or by a brush, stamp, or the like. When using an inkjet method, for example, the inkjet apparatus described above can be used.

[0087] 1.3.3. Fixing Pattern Figure 2 schematically shows an example in which an image 301 made with a first radiation-curable ink and a fixing pattern 302 made with a second radiation-curable ink are formed on a shrink film 300. In the example in Figure 2, the image 301 and the fixing pattern 302 are formed on both the front and back surfaces of the shrink film 300.

[0088] The shrink film 300 is cut into a rectangle, and a bonding portion 303 is provided near the end in the direction of the longer side. The shrink film 300 is then folded along the crease 304, and the end with the bonding portion 303 is bonded to the other end, so that it is folded into an annular shape with the side to which the fixing pattern 302 is attached facing inward.

[0089] The shrink film 300 shown in Figure 2 has its longitudinal direction as the shrinking direction. Therefore, when the shrink film 300 is processed to form a ring, heating it with the object to be packaged placed inside the ring causes it to shrink in the shrinking direction, and the shrink film 300 tightly fastens and attaches the object to be packaged.

[0090] 1.4. Other processes The recording method may also include other steps such as a curing step, a lamination step, and a processing step.

[0091] The curing process involves irradiating at least one of the first radiation-curable ink and the second radiation-curable ink attached to the shrink film with radiation to form a cured coating. When radiation is applied, the polymerization reaction of the polymerizable compound begins, causing the ink to harden and a coating to be formed. At this time, if a polymerization initiator is present, it generates active species (initiators) such as radicals, acids, and bases, and the polymerization reaction of monomers is promoted by the function of these initiators. In addition, if a photosensitizer is present, it absorbs radiation and enters an excited state, and by coming into contact with the polymerization initiator, it promotes the decomposition of the polymerization initiator, thereby achieving a more effective curing reaction.

[0092] The radiation source for the first radiation-curable ink may be a radiation source located downstream of the inkjet head. Similarly, when the second radiation-curable ink is applied by the inkjet method, it may also be irradiated by a radiation source located downstream of the inkjet head. On the other hand, the first and second radiation-curable inks may be irradiated simultaneously or separately by a radiation source outside the inkjet device.

[0093] While there are no particular restrictions on the radiation source, examples include ultraviolet light-emitting diodes (LEDs). Using such a radiation source allows for miniaturization and cost reduction of the device. Because ultraviolet light-emitting diodes are small, they can be installed inside inkjet printers.

[0094] The recording method according to this embodiment may further include a lamination step in which the obtained recording material is stacked such that the recording surface to which the first radiation-curable ink is attached faces the non-recording surface to which the first radiation-curable ink is not attached. Such a lamination step may be performed by winding a long recording material into a roll.

[0095] In industrial applications, recording materials are typically wound into rolls. However, within these rolls, the ink-coated recording surface and its reverse side are pressed together, and the material may be stored and transported in this state.

[0096] Furthermore, the recording method according to this embodiment may include a processing step for processing the obtained recording. The processing step may include, for example, cutting and bonding the recording. The processing step may also include a step of shaping the recording so that it forms an annular shape with the surface to which the second radiation-curable ink is attached as the inner surface.

[0097] Furthermore, the processed recordings may be stacked for storage and transport. Within the stacked processed recordings, the coatings of the first radiation-curable ink, the coatings of the second radiation-curable ink, and / or the shrink film surface may be pressed together, and the recordings may be stored and transported in this state.

[0098] 2. Packaging method The packaging method according to this embodiment includes packaging an object to be packaged using shrink film recorded by the recording method described above.

[0099] Figure 3 is a schematic side view of the shrink film of the embodiment attached to the packaged object. Figure 4 is a schematic top view of the shrink film of the embodiment arranged around the packaged object. Figures 3 and 4 show the state before the shrink film shrinks.

[0100] Figures 3 and 4 illustrate a PET bottle 400 as the object to be packaged. The PET bottle 400 is placed upright on a flat surface, and the shrink film 300 is positioned to surround the PET bottle 400. When the PET bottle 400 is upright, the shrink film 300 is subjected to a downward force due to gravity. However, in this embodiment, a fixing pattern 302 is formed on the surface of the shrink film 300 that is in contact with the PET bottle 400, and the fixing pattern 302 has tackiness (adhesion) to the surface of the PET bottle 400, so even when the PET bottle 400 is upright, downward sliding due to gravity is suppressed.

[0101] As shown in Figures 3 and 4, by shrinking the shrink film 300 while the PET bottle 400 and shrink film 300 are positioned, the shrink film 300 can be attached to the predetermined position for packaging.

[0102] 3. Variations of fixing patterns The fixing patterns can be formed on the side of the shrink film 300 that is in contact with the packaged object, and their size, position, and number are all arbitrary. Figure 5 is a schematic diagram showing some examples of positions for forming the fixing patterns.

[0103] Examples of the arrangement of the fixing patterns include those shown in Figures 5(a) to 5(f). The arrangement of the fixing patterns may be any combination of these arrangements. Furthermore, although not shown, the fixing patterns may be formed on the entire surface of the side that comes into contact with the packaged object.

[0104] Furthermore, the fixing pattern may be positioned to overlap with the image created by the first radiation-curable ink. In this case, it is particularly preferable to use a clear ink for the second radiation-curable ink that forms the fixing pattern, as this does not impair the visibility of the image created by the first radiation-curable ink.

[0105] Furthermore, when the packaged object is positioned upright and the shrink film 300 is placed as shown in Figure 3, the fixing pattern is positioned so that the direction of shrinkage is horizontal. In this case, it is more preferable that the fixing pattern be provided within the lower half of the shrink film 300, as shown in Figures 5(a), (c), and (d). In other words, it is more preferable that the fixing pattern be formed in the area below the center line C, which is parallel to the shrinkage direction of the shrink film 300. This makes it easier to further suppress misalignment, such as the shrink film 300 sliding off the packaged object, when the shrink film 300 is shrunk.

[0106] Figure 6 is a schematic diagram showing another example of the arrangement of the fixing patterns. Figure 7 is a schematic diagram showing the shrink film 300 shown in Figure 6 folded at the crease 304. When folding the shrink film 300 at the crease 304, it is more preferable that the fixing patterns are formed in positions where they do not overlap each other, as shown in Figures 6(g), (h) and 7.

[0107] This is because the fixing pattern has tackiness (adhesion), and for example, when the film is molded to form an annular shape with the side on which the fixing pattern is formed facing inward, and then laminated and stored, the fixing patterns can be prevented from touching each other. As a result, even when annular shrink films are laminated and stored, they are easier to open to form a ring, which improves workability, for example.

[0108] Furthermore, the fixing pattern may not only be recorded as a solid block of the second radiation-curable ink within the area, but may also be recorded in a way that forms dot-like irregularities, for example. This makes it easier to generate frictional force when in contact with the packaged object due to the irregularities, further suppressing displacement of the shrink film 300.

[0109] 4. Effects and Effects According to the recording method of this embodiment, a fixing pattern is formed on the surface that comes into contact with the packaged object, so that misalignment between the shrink film and the packaged object can be suppressed when the shrink film is shrunk. As a result, misalignment between the shrink film and the packaged object can be reduced when the shrink film is shrunk, even without using jigs or the like to position the shrink film relative to the packaged object. Furthermore, when using small lots of multiple types of shrink film, it is not necessary to manufacture jigs or the like for each type, and the man-hours required for the process of setting up jigs or the like for shrinking can be reduced.

[0110] Figure 8 is a schematic diagram of a conventional shrink film placed on a packaged object, viewed from the side. As shown in Figure 8, the conventional shrink film 500 does not have a fixing pattern formed on it. Therefore, conventionally, a jig 700 is used to place the conventional shrink film 500 in a predetermined position on the PET bottle 400. Such a jig 700 needs to be manufactured each time depending on the size of the PET bottle 400 and the position where the shrink film 500 is attached. In contrast, according to the recording method of this embodiment, when using small lots of multiple types of shrink film, it is not necessary to manufacture jigs etc. for each type, and the man-hours for the process of setting up jigs etc. for shrinkage can be reduced.

[0111] Furthermore, according to the packaging method of this embodiment, a fixing pattern is formed on the side of the shrink film that comes into contact with the packaged object, so that misalignment between the shrink film and the packaged object can be suppressed when the shrink film is shrunk. As a result, packaging with reduced misalignment between the shrink film and the packaged object can be performed without using jigs or the like to position the shrink film relative to the packaged object. In addition, when using small lots of multiple types of shrink film, it is not necessary to create jigs or the like for each type, and the process of setting up jigs and the like can be reduced.

[0112] 5. Examples, etc. 5.1. Preparation of radiation-curable inks Each example of radiation-curable ink was obtained by placing the components into a mixing tank to achieve the composition shown in Table 1, mixing and stirring, and then filtering through a 5 μm membrane filter. Each example of radiation-curable ink corresponds to the second radiation-curable ink in the embodiments described above. Unless otherwise specified, the numerical values ​​of each component shown in the table represent mass percent.

[0113] [Table 1]

[0114] The abbreviations and product ingredients used in Table 1 are as follows: [Polymerizable compound] (Monofunctional monomer) ACMO (Acryloylmorpholine, manufactured by KJ Chemicals Co., Ltd.) PEA (Phenoxyethyl acrylate, manufactured by Osaka Organic Chemical Industry Co., Ltd.) (Polyfunctional monomers) VEEA (manufactured by Nippon Shokubai Co., Ltd., 2-(2-vinyloxyethoxy)ethyl acrylate) DPGDA (Dipropylene glycol diacrylate, manufactured by Sartomer Co., Ltd.) [Polymerization initiator] Irgacure819 (Omnirad 819, manufactured by IGM, bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide) TPO (Omnirad TPO, manufactured by IGM, 2,4,6-trimethylbenzoyldiphenylphosphine oxide) DETX (KAYACURE DETX-S (2,4-diethylthioxanthone) (manufactured by Nippon Kayaku Co., Ltd.)) [Polymerization inhibitors] MEHQ (product name "p-methoxyphenol", manufactured by Kanto Chemical Co., Ltd., hydroquinone monomethyl ether)

[0115] Furthermore, each component was placed in a mixing tank to obtain the following composition, mixed and stirred, and then filtered through a 5 μm membrane filter to obtain a radiation-curable ink containing a colorant. This radiation-curable ink corresponds to the first radiation-curable ink in the above-described embodiment. PEA (20% by mass) ACMO (19% by mass) VEEA (26% by mass) DPGDA (16% by mass) Irgacure819 (6% by mass) TPO (4.3% by mass) DETX (4% by mass) MEHQ (0.2% by mass) BYK UV3500 (0.5% by mass) (slip agent) Carbon black (3% by mass) (colorant) Solsperese 36000 (1% by mass) (dispersant) Furthermore, the ratio of monofunctional monomers to total monomers in this ink is 0.48.

[0116] [Surfactants] BYK-UV3500 (manufactured by BYK Additives & Instruments, a silicone-based surfactant) [Dispersion] Dispersant: Solsperse 36000 (Lubrizol, polymer dispersant)

[0117] 5.2. Evaluation Method For the shrink film, we prepared Bonset PET-G (50 μm thick, glycol-modified polyethylene terephthalate). A test pattern was printed on one side of the shrink film using an inkjet method with a radiation-curing ink containing the above-mentioned colorant.

[0118] Subsequently, using a radiation-curable ink that does not contain colorants, a fixing pattern was formed on the other side of the shrink film by inkjet printing, filling a 20 mm x 5 mm area. In the comparative example, no fixing pattern was formed. The shrink film of each example was processed into an annular shape so that the fixing pattern was on the inside.

[0119] Figure 9 shows a schematic of the samples used in the evaluation method. As shown in Figure 9, the fixing patterns of the shrink films for each example were placed in a 500 mL cylindrical PET bottle (height: 210 mm, diameter: 65 mm) so that they were in close contact with each other, and the behavior of the shrink films was observed and evaluated according to the following criteria. The results are listed in Table 1. Evaluation Criteria A: The shrink film does not fall from the PET bottle for more than 1 minute. B: The shrink film adhered tightly to the PET bottle, but fell off within 20 seconds, or within 1 minute. C: The shrink film adhered tightly to the PET bottle, but it fell off within 20 seconds. D: The shrink film does not adhere to the PET bottle.

[0120] The embodiments, examples, and modifications described above are merely examples and are not limiting. For example, it is possible to combine each embodiment and example as appropriate.

[0121] The present invention includes configurations substantially identical to those described in the embodiments, for example, configurations with the same function, method, and results, or configurations with the same purpose and effect. Furthermore, the present invention includes configurations in which non-essential parts of the configurations described in the embodiments are replaced. Furthermore, the present invention includes configurations that produce the same effects or achieve the same purpose as those described in the embodiments. Finally, the present invention includes configurations that add known technology to the configurations described in the embodiments.

[0122] The following can be derived from the embodiments and modifications described above.

[0123] The recording method is: A recording method that uses radiation-curing ink to record on shrink film, The process involves forming an image on the shrink film using a first radiation-curing ink by an inkjet method, The process involves applying a second radiation-curing ink to the surface of the shrink film that comes into contact with the packaged object to form a fixing pattern. Includes.

[0124] This recording method forms a fixing pattern on the surface that contacts the packaged object, thus suppressing misalignment between the shrink film and the packaged object when the shrink film is shrunk. As a result, misalignment between the shrink film and the packaged object can be reduced when shrinking the shrink film without using jigs or other fixtures to position the shrink film relative to the packaged object. Furthermore, when using small batches of multiple types of shrink film, it is not necessary to create jigs or other fixtures for each type, and the process of setting up jigs or other fixtures for shrinking can be reduced.

[0125] In the above recording method, The second radiation-curable ink may be a clear ink.

[0126] This recording method makes it possible to further reduce the influence of the fixing pattern on the visibility and other aspects of the image of the first radiation-curable ink.

[0127] In the above recording method, The shrink film is arranged so that the direction of shrinkage is horizontal when it is shrunk. The fixing pattern may be provided in the lower half of the shrink film in the arrangement described above.

[0128] This recording method makes it easier to suppress misalignment, such as the shrink film slipping off the packaged object, when the shrink film is being shrunk.

[0129] In the above recording method, The second radiation-curable ink may contain 60% by mass or more of monofunctional polymerizable compounds relative to the total amount of polymerizable compounds contained.

[0130] According to this recording method, increasing the monofunctional monomer content improves the adhesion of the second radiation-curable ink to the packaged material, thus making the effect of suppressing misalignment when shrinking the shrink film more pronounced.

[0131] In the above recording method, The first radiation-curable ink may contain a polyfunctional polymerizable compound in an amount of 50% by mass or more relative to the total amount of polymerizable compounds contained.

[0132] According to this recording method, by including a large amount of polyfunctional monomers in the first radiation-curable ink, undesirable blocking of the first radiation-curable ink can be suppressed.

[0133] The packaging method includes packaging the object to be packaged using the shrink film recorded by one of the recording methods described above.

[0134] This packaging method forms a fixing pattern on the side of the shrink film that comes into contact with the packaged object, thereby suppressing misalignment between the shrink film and the packaged object when the shrink film is shrunk. As a result, packaging with reduced misalignment between the shrink film and the packaged object can be performed without using jigs or other fixtures to position the shrink film relative to the packaged object. Furthermore, when using small batches of multiple types of shrink film, it is not necessary to create jigs or other fixtures for each type, thus reducing the process of setting up jigs and other fixtures. [Explanation of symbols]

[0135] 20...Serial printer, 220...Transport unit, 230...Recording unit, 231...Inkjet head, 232...Radiation source, 234...Carriage, 235...Carriage movement mechanism, F...Recording medium, 300...Shrink film, 301...Image, 302...Fixing pattern, 303...Bonding unit, 304...Fold, 400...PET bottle, 500...Conventional shrink film example, 700...Jig, C...Center line, S1, S2...Main scanning direction, T1...Sub-scanning direction

Claims

1. A recording method that uses radiation-curing ink to record on shrink film, The process involves forming an image on the shrink film using a first radiation-curing ink by an inkjet method, The process includes the step of applying a second radiation-curing ink to the surface of the shrink film that comes into contact with the packaged object to form a fixing pattern, The shrink film is arranged so that the direction of shrinkage is horizontal when it is shrunk. A recording method wherein the fixing pattern is provided in the lower half of the shrink film in the arrangement described above.

2. A recording method according to claim 1, wherein the second radiation-curable ink is a clear ink.

3. In claim 1, The recording method wherein the second radiation-curable ink contains 60% by mass or more of monofunctional polymerizable compounds relative to the total amount of polymerizable compounds contained.

4. In claim 1, A recording method wherein the first radiation-curable ink contains 50% by mass or more of a polyfunctional polymerizable compound relative to the total amount of polymerizable compounds contained.

5. A packaging method comprising packaging the object to be packaged using the shrink film recorded by the recording method described in claim 1.

Images