Method for manufacturing a recording object and packaging method for a package

Abstract

Provided is a recording material manufacturing method and a package manufacturing method, which are excellent in blocking resistance and shrinkage properties. A recording material manufacturing method includes: an adhering step of adhering a radiation-curable ink composition to a shrink film; and a curing step of irradiating the radiation-curable ink composition adhered to the shrink film with radiation to form a cured coating film, thereby obtaining a recording material, wherein the weighted average of the glass transition temperatures of the polymerizable compounds contained in the radiation-curable ink composition is 20°C or higher and 70°C or lower.

Description

TECHNICAL FIELD

[0001] The present application relates to a recording material manufacturing method and a package manufacturing method. BACKGROUND

[0002] An inkjet recording method is capable of recording a high-fine image by a simple device, and has been rapidly developed in various aspects. In this connection, a method of recording on various packages by inkjet has been studied. As a film for a package, a shrink film is used, but in the case where a shrink film printed by inkjet is used as a label, there is a problem that the heat resistance of ink is low, and a high-quality printed image cannot be obtained due to dissolution, discoloration, or the like of ink or, at the time of radiation curing, the shrink film is heated due to reaction heat accompanying curing, and unevenly heat shrinks in a heat treatment at the time of mounting on a bottle.

[0003] In view of such a problem, in Patent Literature 1, a shrink film for inkjet recording is disclosed, which uses a resin having a prescribed glass transition temperature (Tg), and has a heat shrinkage rate at the time of heat shrinking for one minute in hot air at 70°C and a heat shrinkage rate at the time of heat shrinking for one minute in hot air at 140°C after further heat shrinking for one minute in hot air at 70°C after shrinking for one minute in hot air at 70°C, which are prescribed values.

[0004] PRIOR ART DOCUMENTS

[0005] PATENT LITERATURE

[0006] Patent Literature 1: Japanese Patent Application Laid-Open No. 2003-285540 SUMMARY

[0007] PROBLEMS TO BE SOLVED BY THE INVENTION

[0008] Generally, packaging with respect to a packaged body such as a plastic bottle is performed by heat shrinking a shrink film. At the time of heat shrinking thereof, depending on the physical properties of a radiation-curable ink composition adhered to the shrink film, there is a possibility that a problem such as wrinkle generation on the coating film occurs.

[0009] TECHNICAL SOLUTION FOR SOLVING THE PROBLEM

[0010] The recording material manufacturing method of the present application comprises: an adhering step of adhering a radiation-curable ink composition to a shrink film; and a curing step of irradiating radiation to the radiation-curable ink composition adhered to the shrink film to form a cured coating film, thereby obtaining a recording material, and the weighted average of the glass transition temperatures of the polymerizable compounds contained in the radiation-curable ink composition is 20°C or higher and 70°C or lower.

[0011] The package manufacturing method of the present application comprises a heating step of heating a recording material obtained by the above-described recording material manufacturing method in a state where the recording material covers a packaged body. Attached Figure Description

[0012] Figure 1 This is a perspective view showing the serial inkjet device of this embodiment.

[0013] Explanation of reference numerals in the attached figures

[0014] 20: Serial printer; 220: Transport section; 230: Recording section; 231: Inkjet head; 232: Radiation source; 234: Carriage; 235: Carriage moving mechanism; F: Recording medium; S1, S2: Main scanning direction; T1: Sub-scanning direction. Detailed Implementation

[0015] The following, as needed, will be referenced in the appendix. Figure 1 The embodiments of the present invention (hereinafter referred to as "this embodiment") will be described in detail, but the present invention is not limited thereto, and various modifications can be made without departing from its spirit. Furthermore, in the accompanying drawings, the same reference numerals are used for the same elements, and repeated descriptions are omitted. In addition, for positional relationships such as up, down, left, and right, the positional relationships shown in the accompanying drawings are used as a reference unless there are special limitations. Moreover, the scale of the accompanying drawings is not limited to the scale shown in the illustrations.

[0016] 1. Methods for manufacturing recordings

[0017] The method for manufacturing a record in this embodiment includes: an attachment step, in which a radiation-curable ink composition is attached to a shrink film; and a curing step, in which the radiation-curable ink composition (hereinafter referred to as "ink composition") attached to the shrink film is irradiated with radiation to form a cured coating film, thereby obtaining a record, wherein the weighted average glass transition temperature of the polymeric compound contained in the radiation-curable ink composition is 20°C or more and 70°C or less.

[0018] In recordings obtained by attaching an ink composition to a shrink film as the recording medium, the ink composition coating cannot completely follow the heat shrinkage of the shrink film, sometimes resulting in wrinkles on the recording surface of the shrunken film. Furthermore, recordings with ink compositions on shrink films are typically stored in a rolled-up manner; during this rolling process, the recording surface of the shrink film comes into contact with the non-recording surface, and there is a tendency for them to stick together.

[0019] In contrast, in the manufacturing method of the recording material of the present embodiment, by adjusting the weighted average of the glass transition temperatures of the polymerizable compounds contained in the radiation-curable ink composition, it is possible to further suppress the generation of wrinkles on the coating film at the time of heat shrinkage of the shrink film, and also to make it less likely to stick when stored in a wound manner. Furthermore, in the following, the case where the generation of wrinkles on the coating film at the time of heat shrinkage is suppressed is referred to as "excellent shrinkage properties", and the case where the sticking of the recording surface to the non-recording surface is suppressed is referred to as "excellent blocking resistance".

[0020] Hereinafter, each process of the manufacturing method of the recording material of the present embodiment will be described in detail, and then the radiation-curable ink composition will be described in detail.

[0021] 1.1. Attachment process

[0022] In the attachment process, the radiation-curable ink composition is attached to the shrink film. The attachment method is not particularly limited, and for example, in addition to the inkjet method, gravure printing, intaglio printing, lithographic printing, and hole printing can be listed. Among them, the inkjet method in which the radiation-curable ink composition is ejected from the inkjet head and attached to the shrink film is preferred. More specifically, the pressure generating unit is driven to cause the composition filled in the pressure generating chamber of the inkjet head to be ejected from the nozzle. By using the inkjet method, it is possible to more easily obtain a high-quality recording material. Furthermore, in the following, the manufacturing method of the recording material of the present embodiment will be described taking the inkjet method as an example, but the manufacturing method of the recording material of the present embodiment is not limited thereto.

[0023] In the inkjet method, the ink composition is ejected from the inkjet head and attached to the recording medium, but more specifically, the pressure generating unit can also be driven to cause the composition filled in the pressure generating chamber of the inkjet head to be ejected from the nozzle.

[0024] As the inkjet head 10 used in the attachment process, a line head that performs recording by the line method and a serial head that performs recording by the serial method can be listed.

[0025] In the line method using the line head, for example, an inkjet head having a width of the recording width of the recording medium or more is fixed to an inkjet device. Then, the recording medium is moved in the sub-scanning direction (the longitudinal direction of the recording medium, the conveying direction), and ink droplets are ejected from the nozzles of the inkjet head in conjunction with this movement, whereby an image is recorded on the recording medium.

[0026] In the serial method using the serial head, for example, the inkjet head is mounted on a carriage that can be moved in the width direction of the recording medium. Then, the carriage is moved in the main scanning direction (the lateral direction of the recording medium, the width direction), and ink droplets are ejected from the nozzle openings of the inkjet head in conjunction with this movement, whereby it is possible to record an image on the recording medium.

[0027] In the adhering step, as the amount of the radiation-curable ink composition adhered to the shrink film, the maximum film thickness of the cured coating film is preferably 7.5 μm or less, more preferably 5 μm or less, and further preferably 1.0 to 5.0 μm. By making the maximum film thickness of the cured coating film 7.5 μm or less, the film thickness of the coating film is thinned when the recording material is wound in the later-described laminating step or the like, and accordingly the volume of the roll can be reduced, so that there is a tendency that the storage efficiency is further improved. In addition, by making the maximum film thickness of the cured coating film 1.0 μm or more, wrinkles are easily generated on the coating film at the time of heating shrinkage, so that the present application is particularly effective.

[0028] In the present embodiment, the shrink film refers to a film having a property of shrinking by 10% or more in at least one direction when heated to 80°C, preferably by 15% or more, more preferably by 20% or more, and further preferably by 30% or more. The higher the shrinkage of the shrink film, the more wrinkles are easily generated on the coating film at the time of heating shrinkage, so that the present application is particularly effective.

[0029] In addition, the shrinkage of the shrink film when heated to 80°C can be calculated by the following formula. The shrinkage can be measured in any direction, and in the present embodiment, the shrinkage in at least one direction in which the shrinkage amount is the largest is within the above-described range. A stretched film obtained by stretching an unstretched film so that the resin is oriented in the stretching direction has a property of shrinking to the size before stretching by relaxing the stress based on the molecular orientation at the time of heating. The shrinkage and the direction thereof can be adjusted by the later-described stretching step, and the shrinkage direction is not particularly limited, and can be the machine direction, the width direction, or both.

[0030] Shrinkage (%) = (length before shrinkage - length after shrinkage) / length before shrinkage

[0031] As the resin constituting the shrink film, there is no particular limitation, and for example, polyolefin-based resins, polyester-based resins, polystyrene-based resins, and polyvinyl chloride-based resins can be exemplified. As an example, the polyester-based resin constituting the shrink film can be exemplified by a polyester-based resin obtained by polycondensation of a dicarboxylic acid component and a polyhydric alcohol component.

[0032] As the dicarboxylic acid component, there is no particular limitation, and for example, aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, naphthalene-1,4- or -2,6-dicarboxylic acid, and sodium m- phthalic acid-5-sulfonate; 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 can be exemplified.

[0033] In addition, in addition to these, hydroxycarboxylic acids such as p-hydroxybenzoic acid, trimellitic anhydride, and pyromellitic anhydride can also be used.

[0034] As the polyol component, there is no particular limitation, and examples include ethylene glycol, diethylene glycol, dipolyol, 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, 1,10-decanediol, and the like alkylene glycols, an oxirane adduct of a bisphenol compound or a derivative thereof, trimethylolpropane, glycerol, pentaerythritol, polyoxytetramethylene glycol, polyethylene glycol, and the like.

[0035] In addition, a polyol other than the above, such as trimethylolpropane, trimethyloloethane, glycerol, diglycerol, pentaerythritol, and the like, can also be used.

[0036] In addition, as the polystyrene-based resin, there is no particular limitation, but examples include polystyrene, poly(p-, m- or o-methylstyrene), poly(2,4-, 2,5-, 3,4- or 3,5-dimethylstyrene), poly(alkylstyrene) such as poly(p-, m- or o-tert-butylstyrene), poly(p-, m- or o-chlorostyrene), poly(p-, m- or o-bromostyrene), poly(p-, m- or o-fluorostyrene), poly(halogenated styrene) such as poly(o-methyl-p-fluorostyrene), poly(halogen-substituted alkylstyrene) such as poly(p-, m- or o-chloromethylstyrene), poly(alkoxystyrene) such as poly(p-, m- or o-methoxystyrene) and poly(p-, m- or o-ethoxystyrene), poly(carboxyalkylstyrene) such as poly(p-, m- or o-carboxymethylstyrene), poly(alkyl ether styrene) such as poly(p-vinylbenzyl propyl ether), poly(alkylsilylstyrene) such as poly(p-trimethylsilylstyrene), and the like.

[0037] The shrink film can also contain a rubber component. As such a rubber component, there is no particular limitation, and examples include a rubber that is a part of or completely hydrogenated from the butadiene portion of a styrene-butadiene block copolymer, a styrene-butadiene copolymer rubber, a styrene-isoprene block copolymer, a rubber that is a part of or completely hydrogenated from the butadiene portion of a styrene-isoprene block copolymer, a methyl methacrylate-butadiene-styrene copolymer rubber, a methyl methacrylate-alkyl acrylate-butadiene-styrene copolymer rubber, and the like.

[0038] The shrink film is preferably a stretched film. As the stretching treatment, either one of uniaxial stretching or biaxial stretching can be adopted. The stretching method is not particularly limited, and for example, a method having a stretching step in which an unstretched film is stretched by 2.0 to 8.0 times, preferably 2.5 to 6.0 times, in a direction having shrinkability at a temperature ranging from Tg - 20°C to Tg + 40°C, where Tg is the glass transition temperature of the resin constituting the shrink film, can be exemplified. After the stretching step, heat treatment can be performed at a temperature of 50 to 110°C while allowing the film to expand by 0 to 15% or relaxing by 0 to 15%.

[0039] 1.2. Curing Step

[0040] In the curing step, a radiation-curable ink composition attached to the shrink film is irradiated with radiation, and a cured coating film is formed, thereby obtaining a recorded matter. When the radiation is irradiated, the polymerization reaction of the polymerizable compound is initiated, and thereby the ink composition is cured to form a coating film. At this time, if a polymerization initiator is present, a radical, an acid, and a base, and the like, active species (initiating species) are generated, and the polymerization reaction of the monomer is promoted by the function of the initiating species. In addition, if a photosensitizer is present, it is excited by absorbing the radiation, and the decomposition of the polymerization initiator is promoted by contacting with the polymerization initiator, and thereby the curing reaction can be further achieved.

[0041] Here, as the radiation, ultraviolet rays, infrared rays, visible rays, X-rays, and the like can be exemplified. As the radiation source, the ink composition is irradiated with a radiation source provided downstream of the inkjet head. As the radiation source, there is no particular limitation, and for example, an ultraviolet light emitting diode can be exemplified. By using such a radiation source, downsizing of the device and reduction of the cost can be achieved. Since the ultraviolet light emitting diode as the ultraviolet source is a small-sized structure, it can be installed in the inkjet device.

[0042] For example, the ultraviolet light emitting diode can be installed in a carriage (along both ends in the medium width direction and / or the medium conveying direction side) on which an inkjet head that ejects a radiation-curable ink composition is mounted. Moreover, low-energy and high-speed curing caused by the components of the above-described radiation-curable ink composition can be achieved.

[0043] 1.3. Laminating Step

[0044] The manufacturing method of the recorded matter of the present embodiment can further have a laminating step in which the obtained recorded matter is overlapped in a manner that a recording surface to which the radiation-curable ink composition is attached faces a non-recording surface to which the radiation-curable ink composition is not attached. Such a laminating step can also be performed by winding the elongated recorded matter in a roll shape.

[0045] In industrial use, the recording material is usually wound in a roll shape, but the inside of the recording material wound in a roll shape is in a state in which the recording surface of the ink-attached coating film and the back surface thereof are pressed, and is stored in this state. In this state, particularly, blocking becomes a problem. Therefore, the present application is particularly effective.

[0046] 2. Packaging method of packaging body

[0047] The packaging method of the packaging body of the present embodiment has a heating step in which the recording material is heated in a state in which the recording material obtained as described above covers the packaging body. Thereby, the recording material after covering the packaging body is heat-shrunk, and by this shrinkage, the packaging body can be packaged.

[0048] Further, at this time, the recording surface can be brought into contact with the packaging body, or the non-recording surface can be brought into contact with the packaging body.

[0049] The condition of the heating step is not particularly limited, and the heating temperature is preferably 70 to 180°C, more preferably 80 to 150°C, and further preferably 90 to 150°C. In addition, the heating time is preferably 3 to 90 seconds, more preferably 5 to 60 seconds, and further preferably 10 to 30 seconds.

[0050] 3. Radiation-curable ink composition

[0051] The radiation-curable ink composition of the present embodiment is cured by irradiation of radiation. As the radiation, ultraviolet rays, electron beams, infrared rays, visible rays, X-rays, and the like can be exemplified. From the aspects that the radiation is easily obtained from a radiation source and is widely used, and that a material suitable for curing by ultraviolet radiation is easily obtained and is widely used, ultraviolet rays are preferable.

[0052] As the components contained in the radiation-curable ink composition of the present embodiment, for example, a polymerizable compound, a polymerization initiator, a polymerization inhibitor, a sensitizer, a surfactant, a color material, and a dispersant, and the like can be exemplified. In addition, the ink composition does not necessarily contain all of these components, and can contain only a part thereof. Hereinafter, the components that can be contained in the radiation-curable inkjet composition to which the present embodiment pertains will be described.

[0053] 3.1. Polymerizable compound

[0054] In the present embodiment, a compound having a polymerizable unsaturated bond is collectively referred to as a polymerizable compound. Furthermore, the polymerizable compound can contain a monofunctional monomer having one polymerizable functional group and a polyfunctional monomer having a plurality of polymerizable functional groups. The polymerizable compound can be used alone or in combination with two or more kinds.

[0055] The weighted average of the glass transition temperature of the polymerizable compounds contained in the radiation-curable ink composition is 20 to 70°C, preferably 25 to 65°C, more preferably 30 to 60°C, and further preferably 35 to 60°C. By making the weighted average of the glass transition temperature 20°C or higher, the blocking resistance is further improved. In addition, by making the weighted average of the glass transition temperature 20°C or higher, there is a tendency that the curing property is further improved. Also, by making the weighted average of the glass transition temperature 70°C or lower, the shrinkage property is further improved.

[0056] Further, the "glass transition temperature of the polymerizable compound" refers to the glass transition temperature of the homopolymer of the polymerizable compound. In addition, the weighted average of the glass transition temperature of the polymerizable compound can be adjusted by using the glass transition temperature of the homopolymer of the polymerizable compound and the contained mass ratio of the polymerizable compound.

[0057] Here, the calculation method of the weighted average of the glass transition temperature of the homopolymer of the polymerizable compound is described. The value of the weighted average of the glass transition temperature of the homopolymer is set to Tg All The glass transition temperature of the homopolymer of each polymerizable compound is set to Tg N The contained mass ratio of the polymerizable compound is set to X N (wt%). N is a number from 1 in order according to the kind of the polymerizable compound contained in the radiation-curable inkjet ink composition. For example, in the case where three kinds of polymerizable compounds are used, Tg1, Tg2, and Tg3 are generated. The weighted average Tg All of the glass transition temperature of the homopolymer is the sum of the product of the glass transition temperature Tg N of the homopolymer calculated from each polymerizable compound and the contained mass ratio X N . Therefore, the following formula (1) holds.

[0058] Tg All =∑Tg N ×X N (1)

[0059] In addition, the measurement method of the glass transition temperature of the homopolymer of the polymerizable compound can be performed by differential scanning calorimetry (DSC) according to JIS K7121. As a measurement device, for example, "DSC6220" manufactured by Advantest Corporation can be used, and as a sample, a sample in which a monomer is polymerized to the extent that the glass transition temperature of the homopolymer thereof is constant can be used.

[0060] The content of the polymerizable compound is more preferably 55 to 85 mass%, more preferably 60 to 80 mass%, and further preferably 65 to 75 mass%, relative to the total amount of the ink composition. By setting the content of the polymerizable compound within the above range, there is a tendency for the blocking resistance, the shrinkage property, or the curing property to further improve.

[0061] 3.1.1. Monofunctional monomer

[0062] The monofunctional monomer is not particularly limited, but for example, a nitrogen-containing monofunctional monomer, an aromatic group-containing monofunctional monomer, a monofunctional monomer having an alicyclic structure, and the like can be exemplified. In addition, other monofunctional monomers can be included as needed instead of or in addition to the above.

[0063] The content of the monofunctional monomer is more preferably 50 mass% or more, more preferably 60 to 95 mass%, further preferably 65 to 90 mass%, and particularly preferably 70 to 85 mass%, relative to the total amount of the polymerizable compound. By setting the content of the monofunctional monomer to 50 mass% or more, there is a tendency for the shrinkage property to further improve. In addition, by setting the content of the monofunctional monomer to 95 mass% or less, there is a tendency for the blocking resistance to further improve.

[0064] Hereinafter, monofunctional monomers will be exemplified, but the monofunctional monomers of the present embodiment are not limited by the following.

[0065] 3.1.1.1. Nitrogen-containing monofunctional monomer

[0066] The polymerizable compound preferably contains a nitrogen-containing monofunctional monomer. Thereby, the hardness of the obtained coating film further improves, and there is a tendency for the blocking resistance to further improve.

[0067] The nitrogen-containing monofunctional monomer is not particularly limited, but for example, a nitrogen-containing monofunctional vinyl monomer such as N-vinylcaprolactam (n-VC), N-vinylformamide, N-vinylcarbazole, N-vinylacetamide, vinylmethyl oxazolidinone (VMOX), and N-vinylpyrrolidone; a nitrogen-containing monofunctional acrylate monomer such as acryloyl morpholine (ACMO); a nitrogen-containing monofunctional methacrylamide monomer such as (meth)acrylamide, N-hydroxymethyl(meth)acrylamide, diacetone acrylamide, N,N-dimethyl(meth)acrylamide, dimethylaminoethyl acrylate benzyl chloride quaternary salt, and the like can be exemplified.

[0068] Among these, it is more preferable to contain either of a monofunctional vinyl monomer containing nitrogen or a monofunctional acrylic ester monomer containing nitrogen, more preferably a monomer having a heterocyclic structure containing nitrogen such as vinyl methyl oxazolidinone, acryloyl morpholine or N-vinyl caprolactam, and further preferably to contain vinyl methyl oxazolidinone. By containing such a monofunctional monomer containing nitrogen, there is a tendency that the jetting stability is further improved because the viscosity of the ink composition is further reduced. In addition, by containing such a monofunctional monomer containing nitrogen, there is a tendency that the blocking resistance, the shrinkage property or the curing property is further improved. Also, since vinyl methyl oxazolidinone is a monomer having a small viscosity at ordinary temperature, by containing vinyl methyl oxazolidinone, there is a tendency that the jetting stability is further improved.

[0069] The content of the monofunctional monomer containing nitrogen is more preferably 15 to 45 mass%, more preferably 20 to 40 mass%, and further preferably 25 to 35 mass% with respect to the total amount of the ink composition. By making the content of the monofunctional monomer containing nitrogen within the above range, there is a tendency that the blocking resistance, the shrinkage property or the curing property is further improved.

[0070] 3.1.1.2. Monofunctional monomer having an aromatic group

[0071] As the monofunctional monomer having an aromatic group, there is no particular limitation, and for example, (meth)acrylic acid phenoxyethyl ester (PEA), (meth)acrylic acid benzyl ester, alkoxylated 2-phenoxyethyl (meth)acrylate, ethoxylated nonyl phenyl (meth)acrylate, alkoxylated nonyl phenyl (meth)acrylate, p-cumyl phenol EO-modified (meth)acrylate and (meth)acrylic acid 2-hydroxy-3-phenoxypropyl ester can be exemplified.

[0072] Among these, (meth)acrylic acid phenoxyethyl ester, (meth)acrylic acid benzyl ester are more preferable, and (meth)acrylic acid phenoxyethyl ester is further preferable. By using such a monofunctional monomer having an aromatic group, there is a tendency that the solubility of the polymerization initiator is further improved, and the curing property of the ink composition is further improved. Especially, in the case of using an acyloxyphosphine-based polymerization initiator or a thioxanthone-based polymerization initiator, there is a tendency that the solubility thereof is made good.

[0073] The content of the monofunctional monomer having an aromatic group is more preferably 25 to 55 mass%, more preferably 30 to 50 mass%, and further preferably 35 to 45 mass% with respect to the total amount of the ink composition. By making the content of the monofunctional monomer having an aromatic group within the above range, there is a tendency that the blocking resistance, the shrinkage property or the curing property is further improved.

[0074] 3.1.1.3. Monofunctional monomer having an alicyclic structure

[0075] As the monofunctional monomer having an alicyclic structure, there is no particular limitation, but for example, a monomer having a monocyclic hydrocarbon group such as t-butylcyclohexyl (meth)acrylate (TBCHA), 3,3,5-trimethylcyclohexyl (meth)acrylate (TMCHA), 2-(meth)acrylic acid-1,4-dioxaspiro[4,5]dec-2-ylmethyl ester, a monomer having an unsaturated polycyclic hydrocarbon group such as dicyclopentenyl (meth)acrylate, dicyclopentenyl oxyethyl (meth)acrylate, a monomer having a saturated polycyclic hydrocarbon group such as dicyclopentyl (meth)acrylate, isobornyl (meth)acrylate (IBXA), and the like can be exemplified.

[0076] Among these, isobornyl (meth)acrylate, t-butylcyclohexyl acrylate, trimethylcyclohexyl (meth)acrylate are more preferable, and isobornyl acrylate is further preferable. By using such a monofunctional monomer having an alicyclic structure, there is a tendency that the blocking resistance, the shrinkage property, or the curing property is further improved.

[0077] Further, the content of the monofunctional monomer having an alicyclic structure is more preferably 15 to 45 mass%, more preferably 20 to 40 mass%, and further preferably 25 to 35 mass% with respect to the total amount of the ink composition. By making the content of the monofunctional monomer having an alicyclic structure within the above range, there is a tendency that the blocking resistance, the shrinkage property, or the curing property is further improved.

[0078] 3.1.2. Multifunctional monomer

[0079] As the multifunctional monomer, there is no particular limitation, but for example, a vinyl group-containing (meth)acrylate, a multifunctional (meth)acrylate can be exemplified. Further, the multifunctional monomer is not limited by the above.

[0080] The content of the multifunctional monomer is more preferably 5 mass% or more, more preferably 10 to 30 mass% or more, and further preferably 15 to 20 mass% with respect to the total amount of the polymerizable compound. By making the content of the multifunctional monomer 5 mass% or more, there is a tendency that the blocking resistance is further improved. Further, by making the content of the multifunctional monomer 40 mass% or less, there is a tendency that the shrinkage property is further improved.

[0081] Hereinafter, a multifunctional monomer is exemplified, but the multifunctional monomer of the present embodiment is not limited by the following.

[0082] 3.1.2.1. Vinyl group-containing (meth)acrylate

[0083] As the (meth)acrylate containing a vinyl group, there is no particular limitation, but for example, a compound represented by the following formula (I) can be cited. By containing such a (meth)acrylate containing a vinyl group, there is a tendency that the anti-blocking property, the shrinkage property, or the curing property is further improved.

[0084] H2C=CR 1 -CO-OR 2 -O-CH=CH-R 3 (I)

[0085] (in the formula, R 1 is a hydrogen atom or a methyl group, R 2 is a divalent organic residue having 2 to 20 carbon atoms, and R 3 is a hydrogen atom or a monovalent organic residue having 1 to 11 carbon atoms).

[0086] In the above formula (I), as the divalent organic residue having 2 to 20 carbon atoms represented by R 2 , a linear, branched, or cyclic, substitutable alkylene group having 2 to 20 carbon atoms; a substitutable alkylene group having 2 to 20 carbon atoms having an ether bond and / or an ester bond in the structure; and a substitutable divalent aromatic group having 6 to 11 carbon atoms can be cited. Among these, an alkylene group having 2 to 6 carbon atoms such as ethylene, n-propylene, iso-propylene, and butylene; an alkylene group having 2 to 9 carbon atoms having an ether bond in the structure such as ethylene oxide, n-propylene oxide, iso-propylene oxide, and butylene oxide are preferable. Furthermore, from the viewpoint that the ink composition can be further lowered in viscosity and the curing property of the ink composition can be further improved, a compound having a glycol ether chain in which R 2 is an alkylene group having 2 to 9 carbon atoms having an ether bond in the structure such as ethylene oxide, n-propylene oxide, iso-propylene oxide, and butylene oxide is more preferable.

[0087] In the above formula (I), as the monovalent organic residue having 1 to 11 carbon atoms represented by R 3 , a linear, branched, or cyclic, substitutable alkyl group having 1 to 10 carbon atoms; and a substitutable aromatic group having 6 to 11 carbon atoms are preferable. Among these, an alkyl group having 1 to 2 carbon atoms such as a methyl group or an ethyl group; and an aromatic group having 6 to 8 carbon atoms such as a phenyl group and a benzyl group are preferable.

[0088] In the case where each of the above-mentioned organic residues is a substitutable group, the substituent can be classified into a group containing a carbon atom and a group not containing a carbon atom. First, in the case where the above-mentioned substituent is a group containing a carbon atom, the carbon atom is counted as the number of carbon atoms of the organic residue. As the group containing a carbon atom, there is no limitation, but for example, a carboxyl group, an alkoxy group can be cited. Next, as the group not containing a carbon atom, there is no limitation, for example, a hydroxyl group, a halogen group can be cited.

[0089] As specific examples of the compound of the formula (I), there are no particular limitations, but for example, 2-vinyloxyethyl (meth)acrylate, 3-vinyloxypropyl (meth)acrylate, 1-methyl-2-vinyloxyethyl (meth)acrylate, 2-vinyloxypropyl (meth)acrylate, 4-vinylobutyl (meth)acrylate, 1-methyl-3-vinyloxypropyl (meth)acrylate, 1-vinyloxymethylpropyl (meth)acrylate, 2-methyl-3-vinyloxypropyl (meth)acrylate, 1,1-dimethyl-2-vinyloxyethyl (meth)acrylate, 3-vinylobutyl (meth)acrylate, 1-methyl-2-vinyloxypropyl (meth)acrylate, 2-vinylobutyl (meth)acrylate, 4-vinylocyclohexyl (meth)acrylate, 6-vinyloxyhexyl (meth)acrylate, 4-vinyloxymethylcyclohexylmethyl (meth)acrylate, 3-vinyloxymethylcyclohexylmethyl (meth)acrylate, 2-vinyloxymethylcyclohexylmethyl (meth)acrylate, p-vinyloxymethylphenylmethyl (meth)acrylate, m-vinyloxymethylphenylmethyl (meth)acrylate, o-vinyloxymethylphenylmethyl (meth)acrylate, 2-(2-vinyloxyethoxy)ethyl (meth)acrylate, 2-(2-vinyloxyethoxy)ethyl acrylate, 2-(vinyloxyisopropoxy)ethyl (meth)acrylate, 2-(vinyloxyethoxy)propyl (meth)acrylate, 2-(vinyloxyethoxy)isopropyl (meth)acrylate, 2-(vinyloxyisopropoxy)propyl (meth)acrylate, 2-(vinyloxyisopropoxy)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-(vinyloxyethoxyethoxyethyl)ethyl (meth)acrylate, 2-(vinyloxyethoxyethoxyethoxyethyl)ethyl (meth)acrylate, 2-(isopropenyloxyethoxy)ethyl (meth)acrylate,(2-ethenyl-oxymethyloxyethyloxyethyloxy)ethyl (meth)acrylate, polyethylene glycol monoethylenyl ether (meth)acrylate, and polypropylene glycol monoethylenyl ether (meth)acrylate. Among these specific examples, 2-(2-ethenyl-oxymethyloxyethyloxy)ethyl acrylate is particularly preferable in terms of easily achieving a balance between the curability and the viscosity of the ink composition. Furthermore, in the present embodiment, 2-(2-ethenyl-oxymethyloxyethyloxy)ethyl acrylate can also be referred to as VEEA.

[0090] The content of the ethylene-containing (meth)acrylate is preferably 1.0 to 10% by mass, more preferably 2.0 to 8.0% by mass, and further preferably 4.0 to 6.0% by mass, relative to the total amount of the ink composition. By setting the content of the ethylene-containing (meth)acrylate within the above range, there is a tendency for the anti-blocking property, the shrinkage property, or the curability to be further improved.

[0091] 3.1.2.2. Polyfunctional (Meth)acrylate

[0092] There is no particular limitation on the polyfunctional (meth)acrylate, but for example, difunctional (meth)acrylates such as 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, EO (oxirane) adduct of bisphenol A di(meth)acrylate, PO (propylene oxide) adduct of bisphenol A di(meth)acrylate, neopentyl glycol di(meth)acrylate of hydroxyneopentanoic acid, and polytetramethylene glycol di(meth)acrylate; and trifunctional or higher polyfunctional (meth)acrylates such as trimethylolpropane tri(meth)acrylate, EO-modified trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, di(trimethylolpropane) tetra(meth)acrylate, glycerol propoxy tri(meth)acrylate, caprolactone-modified trimethylolpropane tri(meth)acrylate, pentaerythritol ethoxy tetra(meth)acrylate, and caprolactam-modified dipentaerythritol hexa(meth)acrylate.

[0093] Among these, more preferable is dipropylene glycol diacrylate (DPGDA). By using such a multifunctional (meth)acrylate, there is a tendency that the curability and the scratch resistance are further improved, and the viscosity is further reduced.

[0094] The content of the multifunctional (meth)acrylate is more preferably 2.5 to 17.5 mass%, more preferably 5.0 to 15 mass%, and further preferably 7.5 to 12.5 mass% relative to the total amount of the ink composition. By making the content of the multifunctional (meth)acrylate within the above range, there is a tendency that the curability of the composition is further improved, and the viscosity is further reduced.

[0095] 3.2. Polymerization initiator

[0096] As the polymerization initiator, there is no particular limitation as long as an active species can be generated by irradiation of a radiation, and for example, known polymerization initiators such as an acyloxyphosphine-based polymerization initiator, an alkylphenyl ketone-based polymerization initiator, a titanocene-based polymerization initiator, a thioxanthone-based polymerization initiator, and the like can be exemplified. Among these, an acyloxyphosphine-based polymerization initiator and a thioxanthone-based polymerization initiator are more preferable, and an acyloxyphosphine-based polymerization initiator is further preferable. By using such a polymerization initiator, there is a tendency that the curability of the composition is further improved. The polymerization initiator can be used alone or in combination with two or more.

[0097] The content of the polymerization initiator is more preferably 2.5 to 17.5 mass%, more preferably 5 to 15 mass%, and further preferably 7.5 to 12.5 mass% relative to the total amount of the ink composition. By making the content of the polymerization initiator within the above range, there is a tendency that the curability of the composition is further improved.

[0098] As the acyloxyphosphine-based polymerization initiator, there is no particular limitation, but for example, 2,4,6-trimethylbenzoyldiphenylphosphine, bis(2,4,6-trimethylbenzoyl)-phenylphosphine, bis-(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine, and the like can be exemplified.

[0099] As a commercial product of such an acyloxyphosphine-based polymerization initiator, there is no particular limitation, but for example, Omnirad 819 (bis(2,4,6-trimethylbenzoyl)-phenylphosphine), IRGACURE 1800 (a mixture of bis-(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine and 1-hydroxy-cyclohexyl-phenyl ketone at a mass ratio of 25:75), Speedcure TPO (2,4,6-trimethylbenzoyldiphenylphosphine), and the like can be exemplified.

[0100] 3.3. Sensitizer

[0101] As the sensitizing agent, there is no particular limitation, but for example, thioxanthone-based compounds can be listed. As the thioxanthone-based compound, there is no particular limitation, but for example, thioxanthone, diethyl thioxanthone, isopropyl thioxanthone, and chlorothioxanthone can be listed.

[0102] As the commercially available product of such a thioxanthone-based polymerization initiator, there is no particular limitation, but for example, Speedcure DETX (2,4-diethyl thioxanthone-9-ketone), Speedcure ITX (2-isopropyl thioxanthone) (manufactured by Lambson Co.), KAYACURE DETX-S (2,4-diethyl thioxanthone) (manufactured by Nippon Kayaku Co., Ltd.) can be listed.

[0103] The content of the sensitizing agent is more preferably 0.5 to 7.5% by mass, more preferably 1.5 to 5.0% by mass, and further preferably 2.5 to 3.5% by mass, relative to the total amount of the ink composition. By making the content of the sensitizing agent within the above range, there is a tendency that the curability of the composition is further improved.

[0104] 3.4. Polymerization Inhibitor

[0105] As the polymerization inhibitor, there is no particular limitation, but for example, 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-tetramethylpiperidyl-1-oxyl, 2,2,6,6-tetramethyl-4-hydroxypiperidine-1-oxyl (LA-7RD), or derivatives of 2,2,6,6-tetramethylpiperidyl-1-oxyl, and the like can be listed.

[0106] The content of the polymerization inhibitor is more 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 ink composition. By making the content of the polymerization inhibitor within the above range, there is a tendency that the storage stability of the ink composition is further improved.

[0107] 3.5. Surfactant

[0108] As the surfactant, there is no particular limitation, but for example, acetylenic diol-based surfactants, fluorine surfactants, and silicone-based surfactants can be listed.

[0109] As the acetylene diol-based surfactant, there is no particular limitation, but for example, 2,4,7,9-tetramethyl-5-decyne-4,7-diol and an oxyalkylene adduct of 2,4,7,9-tetramethyl-5-decyne-4,7-diol, and 2,4-dimethyl-5-decyne-4-ol and an oxyalkylene adduct of 2,4-dimethyl-5-decyne-4-ol can be exemplified.

[0110] As the fluorine-based surfactant, there is no particular limitation, but for example, perfluoroalkyl sulfonate, perfluoroalkyl carboxylate, perfluoroalkyl phosphate, perfluoroalkyl oxirane adduct, perfluoroalkyl betaine, perfluoroalkyl amine oxide compound can be exemplified.

[0111] As the silicone-based surfactant, polysiloxane-based compounds, polyester-modified silicone or polyether-modified organosiloxane, and the like can be exemplified. As the polyester-modified silicone, BYK-347, 348, BYK-UV 3500, 3510, 3530 (all manufactured by BYK Additives & Instruments Co., Ltd.), and the like can be exemplified, and as the polyether-modified silicone, BYK-3570 (manufactured by BYK Additives & Instruments Co., Ltd.), and the like can be exemplified.

[0112] The content of the surfactant is more preferably 0.1 to 1.0% by mass, and even more preferably 0.2 to 0.8% by mass, relative to the total mass of the ink composition. By setting the content of the surfactant within the above range, there is a tendency for the wettability of the ink composition to further improve.

[0113] 3.6. Color material

[0114] The ink composition according to the present embodiment can further include a color material. By including a color material in the ink composition according to the present embodiment, it can be used as a colored ink composition. The color material can use at least one of a pigment and a dye.

[0115] As the inorganic pigment, carbon black (C.I. (Colour Index Generic Name: color index generic name) Pigment Black 7) such as furnace black, lamp black, acetylene black, channel black, iron oxide, titanium oxide can be used.

[0116] As the organic pigment, azo pigments such as insoluble azo pigments, condensed azo pigments, azo lakes, chelate azo pigments, phthalocyanine pigments, perylene and perinone pigments, anthraquinone pigments, quinacridone pigments, dioxane pigments, thioindigo pigments, isoindolinone pigments, quinophthalone pigments, polycyclic pigments such as dye chelates (for example, basic dye type chelates, acid dye type chelates, and the like), dyed lakes (basic dye type lakes, acid dye type lakes), nitro pigments, nitroso pigments, aniline black, daylight fluorescent pigments can be exemplified.

[0117] The total content of the color material is preferably 0.5 to 15% by mass, more preferably 1.0 to 10% by mass, and further preferably 1.5 to 5.0% by mass, relative to the total amount of the ink composition, but can be appropriately changed depending on the kind of ink targeted. In addition, the ink composition according to the present embodiment can not contain a color material or contain a color material to an extent (e.g., 0.1% by mass or less) that does not aim at coloring as a transparent ink.

[0118] As the dye, there is no particular limitation, but for example, acid dyes such as C.I. Acid Yellow, C.I. Acid Red, C.I. Acid Blue, C.I. Acid Orange, C.I. Acid Violet, C.I. Acid Black; basic dyes such as C.I. Basic Yellow, C.I. Basic Red, C.I. Basic Blue, C.I. Basic Orange, C.I. Basic Violet, C.I. Basic Black; direct dyes such as C.I. Direct Yellow, C.I. Direct Red, C.I. Direct Blue, C.I. Direct Orange, C.I. Direct Violet, C.I. Direct Black; reactive dyes such as C.I. Reactive Yellow, C.I. Reactive Red, C.I. Reactive Blue, C.I. Reactive Orange, C.I. Reactive Violet, C.I. Reactive Black; and disperse dyes such as C.I. Disperse Yellow, C.I. Disperse Red, C.I. Disperse Blue, C.I. Disperse Orange, C.I. Disperse Violet, C.I. Disperse Black can be exemplified. One of the above dyes can be used alone, or two or more of them can be used in combination.

[0119] 3.7. Other Components

[0120] The radiation-curable inkjet composition according to the present embodiment can further contain, as needed, a color material such as a pigment, a dye, a dispersant such as a pigment, and an additive.

[0121] 4. Inkjet Apparatus

[0122] As an example of the inkjet apparatus, a perspective view of a serial printer is shown in Figure 1 FIG. 1. As shown in FIG. 1, the serial printer 20 is provided with a conveyance section 220 and a recording section 230. The conveyance section 220 conveys a recording medium F supplied to the serial printer to the recording section 230 and discharges the recorded recording medium to the outside of the serial printer. Specifically, the conveyance section 220 has each conveyance roller that conveys the recording medium F conveyed to the recording section 230 in a sub-scanning direction T1. Figure 1 In addition, the recording section 230 is provided with an inkjet head 231 that ejects a composition to the recording medium F conveyed from the conveyance section 220, a radiation source 232 that irradiates the adhered ink composition with radiation, a carriage 234 that mounts these, and a carriage moving mechanism 235 that moves the carriage 234 in a main scanning direction S1, S2 of the recording medium F.

[0123] In addition, the recording section 230 is provided with an inkjet head 231 that ejects a composition to the recording medium F conveyed from the conveyance section 220, a radiation source 232 that irradiates the adhered ink composition with radiation, a carriage 234 that mounts these, and a carriage moving mechanism 235 that moves the carriage 234 in a main scanning direction S1, S2 of the recording medium F.

[0124] In the case of a serial printer, an inkjet head 231 having a length smaller than the width of the recording medium is provided, and recording is performed in multiple passes by moving the inkjet head. In the serial printer, the inkjet head 231 and the radiation source 232 are mounted on a carriage 234 that moves in a predetermined direction, and the inkjet head moves along with the movement of the carriage to thereby eject the composition onto the recording medium. Thus, recording is performed in two or more passes. Further, a pass is also referred to as a main scan. A sub-scan in which the recording medium is transported between passes is performed. That is, the main scan and the sub-scan are alternately performed.

[0125] Further, the radiation source mounted on the carriage as shown in Figure 1 is not limited thereto, and the radiation source can not be mounted on the carriage.

[0126] Further, the inkjet device of the present embodiment is not limited to the serial printer described above, and can be the line printer described above.

[0127] Example

[0128] Hereinafter, the present application will be further specifically described using examples and comparative examples. The present application is not limited to any of the examples below.

[0129] 1. Preparation of ink composition

[0130] Each component was put in a mixture tank and mixed and stirred, and further filtered using a 5-μm membrane filter, thereby obtaining the ink composition of each example, in accordance with the components described in Table 1. Further, the values of each component shown in the table indicate wt% unless otherwise specified.

[0131] [Table 1]

[0132]

[0133] The abbreviations used in Table 1 and the product components are shown below.

[0134] [Polymerizable compound]

[0135] (Monomer having one functional group)

[0136] VMOX (Vinyl methyl oxazolidinone, manufactured by BASF Corporation)

[0137] ACMO (manufactured by KJ Chemicals Co., Ltd., acryloylmorpholine)

[0138] n-VC (manufactured by ISP Japan Co., Ltd., N-vinyl caprolactam)

[0139] PEA (manufactured by Osaka Organic Chemical Industry, Ltd., phenoxyethyl acrylate)

[0140] IBXA (manufactured by Osaka Organic Chemical Industry, Ltd., isobornyl acrylate)

[0141] (multifunctional monomer)

[0142] VEEA (manufactured by Japan Catalyst Co., Ltd., 2-(2-vinyloxyethoxy)ethyl acrylate)

[0143] DPGDA (manufactured by Sartomer Co., Ltd., dipropylene glycol diacrylate)

[0144] (polymerization inhibitor)

[0145] LA-7RD (manufactured by ADEKA Corporation, trade name 2,2,6,6-tetramethyl-4-hydroxypiperidine-1-oxyl radical)

[0146] MEHQ (trade name "p-methoxyphenol", manufactured by Showa Denko K.K., hydroquinone monomethyl ether)

[0147] (polymerization initiator)

[0148] Omnirad 819 (manufactured by IGM Resins, bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide)

[0149] Speedcure TPO (manufactured by LAMBSON, 2,4,6-trimethylbenzoyl diphenyl phosphine oxide)

[0150] (sensitizer)

[0151] Speedcure DETX (manufactured by LAMBSON, 2,4-diethylthioxanthone-9-ketone)

[0152] (surface active agent)

[0153] BYK-UV3500 (manufactured by BYK Additives & Instruments, organosilicon surface active agent)

[0154] (dispersion)

[0155] dispersant: Solsperse 36000 (manufactured by Lubrizol, high molecular dispersant)

[0156] Bk pigment: carbon black

[0157] 2. Evaluation method

[0158] 2.1. Curing property

[0159] The above obtained radiation-curable ink composition was applied on a PET film with a bar coater so that the film thickness (as the thickness of the cured film) was 10 μm. Irradiation was performed with a UV-LED (peak wavelength 395 nm, irradiation intensity 60 mW / cm 2 ) to find the irradiation energy until the tack-free state was reached. The irradiation energy [mJ / cm 2 ] was a value found from the product of the irradiation intensity [mW / cm 2 ] of the irradiated surface from the light source and the irradiation duration [s].

[0160] The measurement of the irradiation intensity was performed using an ultraviolet intensity meter UM-10, a light receiving portion UM-400 (both manufactured by KONICA MINOLTA SENSING, INC.). In addition, the tack-free state was judged according to the following conditions. That is, it was judged by whether the ink adhered to the cotton swab or the ink cured substance on the recording medium was scratched. At this time, the cotton swab used was a Johnson cotton swab manufactured by Johnson & Johnson. The number of strokes was ten times back and forth, and the strength of the strokes was 100 g load.

[0161] The curing property was evaluated according to the following evaluation criteria based on the irradiation energy until the tack-free state was reached.

[0162] (Evaluation Criteria)

[0163] A: The tack-free energy was less than 150 mJ / cm 2

[0164] B: The tack-free energy was 150 mJ / cm 2 or more and less than 250 mJ / cm 2

[0165] C: The tack-free energy was 250 mJ / cm 2 or more

[0166] 2.2. Blocking

[0167] An inkjet printer "PX-G5000" (product name, manufactured by Seiko Epson Corporation) was used to print on a PET film "Bonset" (product name, TAKIRON Corporation) as a recording medium at normal temperature and pressure at a recording resolution of 600 dpi x 600 dpi and a droplet weight of 20 ng under the condition of a solid image, that is, the dot generation amount was 50% to obtain a printed sample having a film thickness of 5 μm.

[0168] Further, the solid image is an image in which all the pixels of the pixel, which is the minimum recording unit region defined by the recording resolution, are recorded with ink dots. The printing described above is performed, and ultraviolet rays are irradiated from a UV-LED mounted in an ultraviolet irradiation device on the side of the carriage, to obtain a recording material in which a cured film of the ink composition having a film thickness of 5 μm is formed on the recording medium.

[0169] The recording material obtained as described above is wound in a manner that the cured film is on the inner side, and is processed into a cylindrical shape. The recording material is disposed around a container (a glass bottle) that is a packaging target and is preheated in a constant temperature tank, and is left for 10 seconds in a constant temperature tank at 90°C, to shrink the recording material and make it adhere to the container.

[0170] In the packaging of the packaging target described above, for the recording material that is shrunk and made to adhere to the packaging target, whether or not a trace of the cured film adhered to the container is transferred is visually observed, and thus the adhesion is evaluated, and the blocking resistance is evaluated in accordance with the following evaluation criteria.

[0171] (Evaluation Criteria)

[0172] A: The cured film is not adhered to the container

[0173] B: The cured film is slightly adhered to the container

[0174] C: The cured film is adhered to the container (peeling is present)

[0175] 2.2. Shrinkage Property

[0176] For the packaging of the packaging target prepared in the evaluation of the blocking resistance, the occurrence of wrinkles after shrinkage is visually observed, and the shrinkage property is evaluated in accordance with the following evaluation criteria.

[0177] (Evaluation Criteria)

[0178] A: The cured film has no wrinkles

[0179] B: The cured film has slight wrinkles

[0180] C: The cured film has significant wrinkles

Claims

1. A packaging method of a package, characterized by, It has the following processes: The recording medium is used to cover the packaged object, with the recording surface in contact with the packaged object. The recording medium is then heated, causing it to thermally shrink. The recording object is obtained by the following method of manufacturing a recording object, namely, The method for manufacturing the record includes: The adhesion process allows the radiation-curable ink composition to adhere to the shrink film; and In the curing process, the radiation-curable ink composition attached to the shrink film is irradiated with radiation to form a cured coating film, thereby obtaining the recording. The weighted average glass transition temperature of the polymeric compounds contained in the radiation-curable ink composition is above 20°C and below 70°C. The content of monofunctional monomers in the radiation-curable ink composition is 50% to 85% by mass relative to the total amount of the polymeric compound. Polymerizable compounds contain nitrogen-containing monofunctional monomers. The nitrogen-containing monofunctional monomer comprises vinylmethyloxazolidinone.

2. The packaging method for the packaging body according to claim 1, characterized in that, In the adhesion process, the radiation-curable ink composition is adhered to the shrink film such that the maximum film thickness of the cured coating is less than 5 μm.

3. The packaging method for the packaging body according to claim 1, characterized in that, The method for manufacturing the recording further includes a lamination process in which the recording surface with the radiation-curable ink composition attached is overlapped with the non-recording surface without the radiation-curable ink composition attached.

4. The packaging method for the packaging body according to claim 3, characterized in that, The lamination process is performed by winding the record into a roller shape.

5. The packaging method for the packaging body according to claim 1, characterized in that, In the adhesion process, the radiation-curable ink composition is ejected from the inkjet head and adhered to the shrink film.

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