Recording method

Abstract

To provide an ink set that is excellent in laminate peeling strength and blocking resistance of a recorded material.SOLUTION: An ink set according to one embodiment of the invention includes a colored ink composition, which contains a pigment and is a water-based inkjet ink, and a water-based resin liquid composition which contains a resin, in which the resin liquid composition contains a urethane resin having an alicyclic structure or an aromatic ring structure and an acid value of 50 to 100 mg KOH / g.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to an ink set and a recording method. [Background technology]

[0002] Inkjet recording is a method of ejecting small droplets of ink from fine nozzles and depositing them on a recording medium to perform recording. This method is characterized by the ability to record high-resolution, high-quality images at high speed using a relatively inexpensive device. Inkjet recording requires a great many considerations, including the properties of the ink composition used, the stability during recording, and the quality of the resulting image, and research is being actively conducted not only on inkjet recording devices but also on the inkjet inks used.

[0003] In recent years, attempts have been made to apply inkjet inks to non-absorbent media (recording media) that are difficult for ink to adhere to, such as flexible packaging films. Such flexible packaging films are supplied as long roll media, and are wound up and collected after printing. The printed flexible packaging film is then laminated with a sealant film as a base film for use as a packaging material.

[0004] For example, Patent Document 1 discloses an inkjet ink composition intended for printing on soft packaging films, which contains a white or non-white pigment and a urethane resin having an acid value of 5 to 30 mgKOH / g. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2018-123255 A Summary of the Invention [Problem to be solved by the invention]

[0006] However, there are cases where blocking occurs, in which the recording surface sticks to the recording medium, and cases where the laminate peels off, and there are problems with the recorded matter being poor in laminate peel strength and blocking resistance. [Means for solving the problem]

[0007] One aspect of the ink set according to the present invention is An ink set comprising a colored ink composition which is a water-based inkjet ink containing a pigment, and a water-based resin liquid composition which contains a resin, The resin liquid composition contains a urethane resin having an alicyclic structure or an aromatic ring structure and an acid value of 50 to 100 mgKOH / g.

[0008] One aspect of the recording method according to the present invention is to a color ink composition applying step of applying the color ink composition to a recording medium by an ink jet method; and a resin liquid composition applying step of applying the resin liquid composition to the recording medium. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic cross-sectional view showing a configuration of an inkjet recording apparatus. [Diagram 2] FIG. 2 is a perspective view showing an example of a configuration around a carriage of an inkjet recording apparatus. [Diagram 3] FIG. 2 is a schematic plan view showing an example of an arrangement of nozzle groups in an inkjet head. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, an embodiment of the present invention will be described. The embodiment described below is an example of the present invention. The present invention is not limited to the following embodiment, and includes various modified forms that are implemented within the scope that does not change the gist of the present invention. Note that not all of the configurations described below are necessarily essential configurations of the present invention.

[0011] 1. Ink set An ink set according to one embodiment of the present invention comprises a colored ink composition which is a water-based inkjet ink containing a pigment, and a water-based resin liquid composition which contains a resin, and the resin liquid composition contains a urethane resin having an alicyclic structure or an aromatic ring structure and an acid value of 50 to 100 mgKOH / g.

[0012] When recording on a recording medium using a color ink composition containing a pigment, there is a problem that the laminate peel strength and blocking resistance of the recorded matter are poor. It is considered that such a problem occurs because pigments generally do not have adhesive properties. In particular, a recorded matter using a white ink containing a white pigment as a color ink composition tends to have poorer laminate peel strength, blocking resistance, and abrasion resistance, and among these, laminate peel strength is particularly likely to be poor. In white ink, one of the reasons for this is that the pigment content is high and the average particle size of the pigment is large. In addition, non-white inks containing non-white pigments also tend to have poor laminate peel strength and, in particular, poor blocking resistance.

[0013] Furthermore, if an attempt is made to obtain sufficient laminate peel strength and blocking resistance by increasing the amount of resin added to the ink, the viscosity of the ink will increase, which may reduce the ability to recover from clogging in the nozzles of the inkjet head, and this is not a simple matter.

[0014] The ink set according to the present embodiment is characterized by comprising a resin liquid composition containing a urethane resin having a specific structure and an acid value within a specific range (hereinafter also referred to as "specific resin"). According to an ink set comprising a resin liquid composition containing such a specific resin and a colored ink composition containing a pigment, it is possible to achieve both excellent laminate peel strength and blocking resistance of the recorded matter, and excellent clogging recovery properties.

[0015] By incorporating a specific resin into the resin liquid composition as in the ink set according to this embodiment and attaching it to a recording medium separately from the colored ink composition, it becomes possible to concentrate the specific resin at the interface in the colored ink composition layer, i.e., the interface between the recording medium and the colored ink composition layer and the interface between the colored ink composition layer and the air layer. This makes it possible to reduce the amount of pigment present at the interface of the colored ink composition layer, and it is presumed that this has prevented the deterioration of laminate peel strength and blocking resistance caused by the presence of the pigment.

[0016] On the other hand, when a specific resin is contained in a colored ink composition without using a resin liquid composition, in order to obtain sufficient laminate peel strength and blocking resistance, that is, to concentrate a sufficient amount of the specific resin at the interface in the colored ink composition layer, it is necessary to use a large amount of the specific resin relative to the colored ink composition. In this way, when a large amount of resin is contained in the colored ink composition, the viscosity of the ink tends to increase. In addition, in order to reduce the increase in viscosity, it is necessary to reduce the amount of organic solvent that can be contained, and the moisturizing effect of the organic solvent cannot be obtained sufficiently. Furthermore, it is speculated that one of the reasons is that the dispersion stability of both the specific resin and the pigment is easily reduced by containing a large amount of the specific resin. Therefore, when a specific resin is contained in a colored ink composition, it is not possible to achieve both print image quality and ejection reliability such as clogging recovery. In particular, when the colored ink composition is white, This problem becomes more pronounced in white inks that contain color pigments, because the pigment content in white inks is higher than that in non-white inks, and when a large amount of resin is added, the ink becomes more viscous, which tends to reduce clogging recovery properties.

[0017] In contrast, with the ink set according to this embodiment, the viscosity of the colored ink composition, particularly the white ink, can be maintained at an appropriate level, and it is possible to achieve both excellent laminate peel strength and blocking resistance as well as excellent ejection reliability, such as print image quality and clogging recovery properties.

[0018] An ink set is one in which the inks included in the ink set are used as a set for recording. In other words, an ink set refers to two or more inks used as a set for recording. The inks included in an ink set may each be contained in an individual ink container. Examples of ink containers include packs, bottles, and jars. They may also be cartridges that can be installed in a printer.

[0019] The resin liquid composition and colored ink composition constituting the ink set according to this embodiment, and recorded matter using the ink set according to this embodiment will be described below.

[0020] 1.1. Resin liquid composition The aqueous resin liquid composition constituting the ink set according to this embodiment contains a urethane resin having an alicyclic structure or an aromatic ring structure and an acid value of 50 to 100 mgKOH / g. Each component contained in the resin liquid composition will be described below.

[0021] 1.1.1.Urethane resin The urethane resin is a resin polymerized using polyisocyanate, and is polymerized using at least polyisocyanate, polyol and / or polyamine. In particular, it is polymerized using polyisocyanate and polyol. If necessary, it is polymerized using polyol or polyamine as a crosslinking agent or chain extender.

[0022] The urethane resin is a polyurethane containing one or more groups selected from a urethane bond (urethane group) formed by the reaction of an isocyanate group with a hydroxyl group, and a urea bond (urea group) formed by the reaction of an isocyanate group with an amino group, and may be linear or branched.

[0023] Furthermore, the term "polyurethane" includes those that have thermoplasticity regardless of whether they have a crosslinked structure, and those that have a crosslinked structure and therefore exhibit no or only a slight Tg or melting point.

[0024] The isocyanate group for forming the urethane bond is supplied from a compound containing an isocyanate group. Also, the hydroxyl group for forming the urethane bond is supplied from a compound containing a hydroxyl group. Then, in order to polymerize, a compound having two or more isocyanate groups and a compound having two or more hydroxyl groups are selected and polymerized.

[0025] In this specification, a compound having two or more isocyanate groups is sometimes referred to as a polyisocyanate, and a compound having two or more hydroxyl groups is sometimes referred to as a polyol. Of these, a compound having two isocyanate groups is sometimes referred to as a diisocyanate, and a compound having two hydroxyl groups is sometimes referred to as a diol.

[0026] In addition, the molecular chain between the isocyanate groups of the polyisocyanate and the hydro group of the polyol The molecular chain between the alkoxyl groups and the molecular chain between the amino groups of the polyamine become the parts other than the urethane bonds or urea bonds when the polyurethane is formed. In this specification, all or part of the parts other than the urethane bonds or urea bonds when the polyurethane is formed may be referred to as the skeleton. The skeleton may be linear or branched.

[0027] In addition, polyurethane may contain bonds other than urethane bonds and urea bonds, and examples of such bonds include urea bonds formed by the reaction of multiple isocyanate bonds with water, biuret bonds formed by the reaction of urea bonds with isocyanate groups, alphanate bonds formed by the reaction of urethane bonds with isocyanate groups, uretdione bonds formed by dimerization of isocyanate groups, and isocyanurate bonds formed by trimerization of isocyanate groups. These bonds can be actively formed or prevented by the reaction temperature, etc. Therefore, for example, when polyisocyanate, polyol, and polyamine coexist in the reaction system, polyurethane containing these bonds (groups) in addition to urethane bonds and urea bonds can be generated. By having an allophanate structure, a biuret structure, a uretdione structure, and an isocyanurate structure, adhesion to a recording medium is increased, film strength is increased, and abrasion resistance may be improved.

[0028] In this specification, a compound having two or more amino groups is also called a polyamine, and the term is used in the same manner as the above-mentioned polyisocyanates and polyols.

[0029] The urethane resin is a reaction product of a polyisocyanate and an active hydrogen compound. The urethane resin contained in the resin liquid composition used in the ink set according to this embodiment has an alicyclic structure or an aromatic ring structure. For this reason, it is obtained by polymerization using a component having an alicyclic structure or an aromatic ring structure. In particular, it is preferable to obtain it by polymerization using at least a polyisocyanate and a polyol having an alicyclic structure or an aromatic ring structure. It may also be polymerized using a polyamine, and further, polyols, polyamines, etc. as crosslinking agents or chain extenders may also be used as necessary. In addition, polyols and polyamines may be used as components having an alicyclic structure or an aromatic ring structure. The components of the urethane resin will be described below.

[0030] 1.1.1.1. Polyisocyanates Examples of polyisocyanates include polyisocyanate monomers and / or polyisocyanate derivatives. Examples of polyisocyanate monomers include aromatic polyisocyanates, alicyclic polyisocyanates, and aliphatic polyisocyanates. The urethane resin contained in the aqueous resin liquid composition constituting the ink set according to this embodiment has an alicyclic structure or an aromatic ring structure, and therefore, it is preferable to use at least one selected from aromatic polyisocyanates and alicyclic polyisocyanates as the polyisocyanate monomer. When the urethane resin contained in the resin liquid composition has an alicyclic structure or an aromatic ring structure, the wettability to a recording medium made of a polyolefin-based non-polar material tends to be improved, and the resin liquid composition can be applied uniformly. This makes it possible to reduce the pigment present in the interface between the colored ink composition layer and the recording medium, and to prevent a decrease in laminate peel strength and blocking resistance.

[0031] Examples of aromatic polyisocyanates include 2,4- or 2,6-tolylene diisocyanate or mixtures thereof (TDI), m-, p-phenylene diisocyanate or mixtures thereof, 4,4'-diphenyl diisocyanate, 1,5-naphthalene diisocyanate (NDI), 4,4'-, 2,4'-, or 2,2'-diphenylmethane diisocyanate or mixtures thereof (MDI), 4,4'-toluidine diisocyanate (TODI), 1,3- or 1,4-bis(isocyanatomethyl)benzene or mixtures thereof (XDI), 1,3- or 1,4-bis(isocyanatopropyl)benzene or mixtures thereof ( TMXDI), ω,ω'-diisocyanate-1,4-diethylbenzene, etc.

[0032] Examples of alicyclic polyisocyanates include 1,3-cyclopentane diisocyanate, 1,3-cyclopentene diisocyanate, 1,4-cyclohexane diisocyanate, 1,3-cyclohexane diisocyanate, isophorone diisocyanate (IPDI), 4,4'-, 2,4'-, or 2,2'-dicyclohexylmethane isocyanate, methyl-2,4-cyclohexane diisocyanate, methyl-2,6-cyclohexane diisocyanate, norbornane diisocyanate (various isomers or mixtures thereof) (NBDI), 1,3-, or 1,4-bis(isocyanate)methylcyclohexane, or mixtures thereof (H6XDI), and the like.

[0033] Examples of aliphatic polyisocyanates include ethylene diisocyanate, trimethylene diisocyanate, 1,2-propylene diisocyanate, tetramethylene diisocyanate, 1,2-butylene diisocyanate, 2,3-butylene diisocyanate, 1,3-butylene diisocyanate, 1,5-pentamethylene diisocyanate (PDI), and 1,6-hexamethylene diisocyanate (HDI).

[0034] These polyisocyanate monomers can be used alone or in combination of two or more kinds.

[0035] Examples of the polyisocyanate derivative include polymers of the above-mentioned polyisocyanate monomers, allophanate-modified products, polyol-modified products, biuret-modified products, urea-modified products, oxadiazinetrione-modified products, carbodiimide-modified products, uretdione-modified products, and uretonimine-modified products.

[0036] Further, examples of polyisocyanate derivatives include polymethylene polyphenylene polyisocyanate (also called polymeric MDI or crude MDI).

[0037] The urethane resin contained in the aqueous resin liquid composition constituting the ink set according to this embodiment is preferably one that uses one or more of these polyisocyanates selected from dicyclohexylmethane diisocyanate, isophorone diisocyanate, 1,3-bis(isocyanatemethyl)cyclohexane, m-bis(isocyanatepropyl)benzene, and m-bis(isocyanatemethyl)benzene as a constituent component. The phrase "used as a constituent component" means that the urethane resin is used as a raw material for synthesizing the urethane resin, and the urethane resin has a structure resulting from this. When the urethane resin contained in the resin liquid composition uses these polyisocyanates as constituent components, the wettability to a recording medium made of a polyolefin-based non-polar material tends to be improved. Therefore, the resin liquid composition can be applied more uniformly, and as a result, the laminate peel strength and blocking resistance tend to be improved.

[0038] Furthermore, dicyclohexylmethane diisocyanate may be a mixture of dicyclohexylmethane 4,4'-diisocyanate, dicyclohexylmethane 2,2'-diisocyanate and dicyclohexylmethane 2,4'-diisocyanate, or each of these may be used alone. Furthermore, it may be used as a polyfunctional isocyanate consisting of a dimer or more of any combination of these. A polyfunctional polyisocyanate has a structure consisting of two or more molecules of polyisocyanate, and reacts with OH groups or NH groups of polyols, polyamines, etc. 2 It is a compound having two or more isocyanate groups at the molecular terminals in order to react with the isocyanate group. These multifunctional polyisocyanates may contain at least one structure selected from the group consisting of an allophanate structure, a uretdione structure, an isocyanurate structure, and a biuret structure.

[0039] The multifunctional polyisocyanate is a structure consisting of two or more molecules of monomeric diisocyanate or polymeric polyisocyanate, and may have many branches in the molecule. Such a polymer having a structure consisting of a multifunctional polyisocyanate has a structure in which the molecules are three-dimensionally entangled in a complex manner and urethane bonds are densely packed. Therefore, even if the acid value is relatively low, it can be stably dispersed in the resin liquid composition. By using these polyisocyanates, the adhesion of the formed image to the recording medium may be improved.

[0040] The polyisocyanate may be a structure consisting of two or more molecules of polyisocyanate. The structure consisting of two or more molecules of polyisocyanate is, for example, a uretdione structure or an isocyanurate structure. If such a polyisocyanate is selected, the polyurethane will have a structure in which the molecules are three-dimensionally entangled in a complex manner and the urethane bonds are densely packed. Therefore, even if the polyurethane has a low acid value, it can be stably dispersed in the resin liquid composition.

[0041] In this specification, the skeleton of polyurethane refers to the molecular chain between functional groups. Therefore, the urethane resin contained in the aqueous resin liquid composition constituting the ink set according to this embodiment has a skeleton derived from the molecular chain of raw materials such as polyisocyanate, polyol, polyamine, etc. Other skeletons are not particularly limited, but may be, for example, substituted or unsubstituted saturated, unsaturated or aromatic chains, and such chains may have carbonate bonds, ester bonds, amide bonds, etc. In addition, the type and number of substituents in such skeletons are not particularly limited, and may include alkyl groups, hydroxyl groups, carboxyl groups, amino groups, sulfonyl groups, phosphonyl groups, etc.

[0042] 1.1.1.2. Polyols The urethane resin contained in the aqueous resin liquid composition constituting the ink set according to this embodiment can be obtained by using polyol as a raw material. There are no particular limitations on the polyol as long as it is a bifunctional or higher functional compound, i.e., a compound having two or more hydroxyl groups. Examples of the polyol include alkylene glycol, polyester polyol, polyether polyol, and polycarbonate diol.

[0043] Examples of alkylene glycols include ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol, 1,2-propylene glycol, 1,3-propanediol, tripropylene glycol, polypropylene glycol, polytetramethylene glycol, hexamethylene glycol, tetramethylene glycol, neopentyl glycol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1,2-pentanediol, 1,5-pentanediol, 1,2-hexanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 1, Examples of the polytetramethylene glycol include 2-cyclohexanediol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, 4,4-dihydroxyphenylpropane, 4,4-dihydroxyphenylmethane, glycerin, trimethylolethane, trimethylolpropane, 1,2,5-hexanetriol, 1,2,6-hexanetriol, pentaerythritol, trimethylolmelamine, polyoxypropylenetriol, dimethyl-1,3-pentanediol, diethyl-1,3-pentanediol, dipropyl-1,3-pentanediol, dibutyl-1,3-pentanediol, 2-butyl-2-ethyl-1,3-propanediol, etc. Commercially available polytetramethylene glycol products can be used, such as PTMG250, PTMG2000, PTMG3000, and PTMG4000 manufactured by Mitsubishi Chemical, and PTG and PTMG-L manufactured by Hodogaya Chemical.

[0044] Among these, the urethane resin contained in the aqueous resin liquid composition constituting the ink set according to this embodiment uses polytetramethylene glycol as a constituent component. When polytetramethylene glycol is used as a raw material for polyurethane, the polytetramethylene glycol penetrates into the three-dimensional network structure formed in the polyurethane and reacts with isocyanate to form urethane bonds, which tends to produce a urethane resin with a better balance of strength and flexibility. This tends to further improve laminate peel strength and blocking resistance.

[0045] In addition, when polytetramethylene glycol is used as a raw material for polyurethane, its number average molecular weight is preferably 200 to 4000, more preferably 500 to 3000, and particularly preferably 1000 to 2500. If the number average molecular weight is 500 or more, the density of the urethane bond in the polyurethane is not increased too much, and the rigidity of the molecular chain derived from polytetramethylene glycol can be suppressed. This increases the flexibility of the polyurethane and may improve the laminate peel strength. In addition, if the number average molecular weight of polytetramethylene glycol reacting with polyisocyanate is 3000 or less, the density of the urethane bond in the polyurethane is not too small, the extensibility of the molecular chain derived from polytetramethylene glycol is not increased too much, and the flexibility of the polyurethane is suppressed, so that tackiness is unlikely to occur and blocking resistance may be improved. Therefore, when the number average molecular weight of polytetramethylene glycol is 500 or more and 3,000 or less, the film (image) formed by the polyurethane has a good balance between strength and flexibility, which tends to further improve the laminate peel strength and blocking resistance.

[0046] In the present invention, the "number average molecular weight" is obtained by dividing the total weight of a polymer by the total number of molecules constituting the polymer, and is measured by the GPC method.

[0047] Examples of polyester polyols include acid esters. Examples of acid components constituting the acid ester include aliphatic dicarboxylic acids such as malonic acid, succinic acid, tartaric acid, oxalic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, alkyl succinic acid, linoleic acid, maleic acid, fumaric acid, mesaconic acid, citraconic acid, and itaconic acid, and alicyclic dicarboxylic acids such as phthalic acid, naphthalenedicarboxylic acid, biphenyldicarboxylic acid, tetrahydrophthalic acid, and aromatic hydrogenated products. Anhydrides, salts, alkyl esters, and acid halides of these acid components can also be used as the acid component. In addition, the alcohol component constituting the acid ester is not particularly limited, and the above-mentioned diol compounds can be exemplified.

[0048] Examples of polyether polyols include addition polymers of alkylene oxides and condensation polymers of polyols such as (poly)alkylene glycols. Examples of alkylene oxides include ethylene oxide, propylene oxide, butylene oxide, and α-olefin oxide. Examples of (poly)alkylene glycols include polyethylene glycol (polyoxyethylene glycol), polypropylene glycol (polyoxypropylene glycol), and polybutylene glycol. Among these, the use of polyoxypropylene glycol tends to improve the flexibility of polyurethane, and improve the abrasion resistance and gloss when printed on a film. Commercially available polyoxypropylene glycols can be used, such as the Exenol series manufactured by Asahi Glass Co., Ltd., the Newpol PP series manufactured by Sanyo Chemical Industries, Ltd., and the Uniol D series manufactured by NOF Corporation.

[0049] Polycarbonate diol contains two hydroxyl groups and a molecular chain with a carbonate bond.

[0050] Examples of polycarbonate diols that can be used as part or all of the polyol in this embodiment Examples of the polycarbonate diol include polycarbonate diols obtained by reacting a carbonate component such as alkylene carbonate, diaryl carbonate, or dialkyl carbonate, phosgene, and an aliphatic polyol component, and further include alkanediol-based polycarbonate diols such as polyhexamethylene carbonate diol. By using a polycarbonate diol as a starting material for polyurethane, the heat resistance and hydrolysis resistance of the polyurethane produced tends to be good.

[0051] By using a polycarbonate diol as the polyether, the polyurethane has a skeleton derived from the polycarbonate diol, and therefore the scratch resistance of the resulting image tends to be further improved.

[0052] Polycarbonate diols suitable as raw materials for the urethane resin contained in the aqueous resin liquid composition constituting the ink set according to this embodiment generally have two hydroxyl groups in the molecule, and can be obtained by transesterification of a diol compound with a carbonate ester. Examples of such diol compounds include 1,4-butanediol, 1,3-butanediol, 1,2-butanediol, 1,5-pentanediol, 1,2-pentanediol, 1,6-hexanediol, 1,5-hexanediol, 1,2-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,2-octanediol, 1,9-nonanediol, 1,10-decanediol, neopentyl glycol, 4-methyl-1,5-pentanediol, 2-methyl-1,3-propanediol, 2-methyl-1,3-propanediol, 2-methyl-1,4-propanediol, 2-methyl-1,5-propanediol, 2-methyl-1,6-propanediol, 2-methyl-1,7-propanediol, 2-methyl-1,5-propanediol, 2-methyl-1,6 ... 2-methyl-1,8-octanediol, 2-isopropyl-1,4-butanediol, 2-ethyl-1,6-hexanediol, 3-methyl-1,5-pentanediol, 2,4-dimethyl-1,5-pentanediol, 2,4-diethyl-1,5-pentanediol, 1,3-butanediol, 2-ethyl-1,3-hexanediol, 2-butyl-2-ethyl-1,3-propanediol, 1,4-cyclohexanedimethanol, 1,3-cyclohexanediol, 1,4-cyclohexanediol, etc. These can be used alone or in combination of two or more kinds. Among the above diols, neopentyl glycol, 4-methyl-1,5-pentanediol, 2-methyl-1,3-propanediol, 2-methyl-1,8-octanediol, 2-isopropyl-1,4-butanediol, 2-ethyl-1,6-hexanediol, 3-methyl-1,5-pentanediol, 2,4-dimethyl-1,5-pentanediol, and 2,4-diethyl-1,5-pentanediol are more preferable, as they are less likely to crystallize.

[0053] Carbonate esters usable for producing polycarbonate diols are not limited as long as they do not impair the effects of the present invention, and include dialkyl carbonates, diaryl carbonates, and alkylene carbonates. Among these, diaryl carbonates are preferred from the viewpoint of reactivity. Specific examples of carbonate compounds include dimethyl carbonate, diethyl carbonate, dibutyl carbonate, diphenyl carbonate, ethylene carbonate, etc., and diphenyl carbonate is more preferred.

[0054] Commercially available polycarbonate diols include, for example, NL1010DB, NL2010DB, NL3010DB, NL1010B, NL2010B, NL3010B, NL1050DB, NL2050DB, and NL3050DB from the BENEBiOL series manufactured by Mitsubishi Chemical, the DURANOL series from Asahi Kasei Chemicals, the NIPPOLAN series from Tosoh, polyhexanediol carbonate from Kuraray, the PLACCEL series and CDCD205PL manufactured by Daicel Chemical Industries, and the ETERNACOLL series manufactured by Ube Industries.

[0055] When a polyol is used as a raw material for the urethane resin contained in the aqueous resin liquid composition constituting the ink set according to this embodiment, it is more preferable that an acid group is present in the molecule of the polyol. Examples of suitable diols include dimethylolpropionic acid (DMPA), dimethylolbutanoic acid, and dimethylolbutyric acid. Of these, dimethylolpropionic acid and dimethylolbutanoic acid are more preferred. Since the resin liquid composition constituting the ink set according to this embodiment is water-based, it is more preferred that the polyurethane is polymerized using such an acid group-containing diol as a raw material.

[0056] The urethane resin polymerized using such components is mainly composed of two types of segments, hard segments and soft segments. The hard segments are composed of polyisocyanate, short-chain polyol, polyamine, crosslinking agent, chain extender, etc., and mainly contribute to the strength of the polyurethane. On the other hand, the soft segments are composed of long-chain polyol, etc., and are mainly said to contribute to the flexibility of the resin. Then, the resin liquid composition is attached to the recording medium, and the coating formed by the polyurethane has both strength and flexibility and has high elasticity because these hard segments and soft segments have a microphase separation structure. Such characteristics of the coating contribute to improving the laminate peel strength and blocking resistance of the recording material.

[0057] 1.1.1.3. Other components of urethane resin <Polyamine> The raw material of the urethane resin contained in the aqueous resin liquid composition constituting the ink set according to this embodiment may contain a polyamine. The polyamine is not particularly limited as long as it is a compound having a bifunctional or higher functional amino group.

[0058] Examples of polyamines include aliphatic diamines such as ethylenediamine, propylenediamine, 2,2-dimethyl-1,3-propanediamine, 2-methyl-1,5-pentanediamine, trimethylhexanediamine, 2-butyl-2-ethyl-1,5-pentanediamine, 1,8-octanediamine, 1,9-nonanediamine, and 1,10-decanediamine, diethylenetriamine, hexylenediamine, triethylenetetramine, tetraethylenepentamine, isophoronediamine, and xylylenediamine. , diphenylmethanediamine, hydrogenated diphenylmethanediamine, hydrazine, polyamidepolyamine, polyethylenepolyimine, 1-amino-3-aminomethyl-3,5,5-trimethylcyclohexane, dicyclohexylmethanediamine, bicycloheptane dimethaneamine, menthene diamine, diaminodicyclohexylmethane, isopropyltrimethylcyclohexyl-4,4'-diamine, 1,4-diaminocyclohexane, 1,3-bisaminomethylcyclohexane, and the like.

[0059] Many of the compounds commonly used as polyamines have molecular weights comparable to those of short-chain polyols, and basically form urea or biuret groups, which are hard segments of polyurethane. The polymer formed contains urea groups, so the polymer can be called a urea resin.

[0060] Polyamines can also be used as components to react with polyfunctional polyisocyanates, chain extenders, crosslinking agents, etc., but when an isocyanate group reacts with an amino group, a urea bond is formed. Therefore, when using polyamines, the amount used is determined so that the ratio of urea groups / urethane groups in the polyurethane is the desired ratio, and the physical properties of the polyurethane can be controlled.

[0061] <Crosslinking agents and chain extenders> The urethane resin contained in the aqueous resin liquid composition that constitutes the ink set according to this embodiment may contain a crosslinking agent and / or a chain extender.

[0062] Crosslinking agents are used during the synthesis of prepolymers, and chain extenders are used to extend the chain after the synthesis of prepolymers. The crosslinking agent and chain extender can be appropriately selected from the above-mentioned polyisocyanates, polyols, polyamines, etc., depending on the application such as crosslinking or chain extension.

[0063] The chain extender is, for example, a compound that reacts with the isocyanate group of the above-mentioned polyisocyanate that does not form a urethane bond. Examples of compounds that can be used as the chain extender include the above-mentioned polyols and polyamines. In addition, compounds that can crosslink polyurethane can also be used as the chain extender. Examples of compounds that can be used as the chain extender include low molecular weight polyols and polyamines with a number average molecular weight of less than 500.

[0064] In addition, the crosslinking agent may be a polyisocyanate, a polyol, or a polyamine having three or more functional groups. Examples of the polyisocyanate having three or more functional groups include a polyisocyanate having an isocyanurate structure, and a polyisocyanate having an allophanate or biuret structure. Examples of the polyol may include glycerin, trimethylolpropane, pentaerythritol, polyoxypropylenetriol, and the like. Examples of the polyamine having three or more functional groups include a trialcoholamine such as triethanolamine or triisopropanolamine, and an amine having three or more functional amino groups such as diethylenetriamine or tetraethylenepentamine.

[0065] The presence or absence of crosslinking in polyurethane can be determined by the gel fraction, which is calculated by calculating the ratio of gel to sol using the phenomenon that polyurethane having a crosslinked structure does not dissolve in a solvent and swells. The gel fraction is an index of the degree of crosslinking measured from the solubility of solidified polyurethane, and the higher the degree of crosslinking, the higher the gel fraction tends to be.

[0066] 1.1.1.4.Synthesis of urethane resin The urethane resin contained in the aqueous resin liquid composition constituting the ink set according to this embodiment may be resin particles. In this way, when the resin is particulate, that is, resin particles, as the resin liquid composition dries, the resin particles are fused and fixed to each other, so that the fixing property of the image part of the recorded matter tends to improve, and the laminate peel strength and blocking resistance may be further improved. The resin particles made of urethane resin can be obtained by using a known method. An example will be described below.

[0067] Polyisocyanate and compounds that react with it (polyol, and if necessary, polyamine, etc.) are reacted in amounts that increase the amount of isocyanate groups, and a prepolymer having isocyanate groups at the ends of the molecules is polymerized. If necessary, organic solvents with a boiling point of 100°C or less and no groups that react with isocyanate groups, such as methyl ethyl ketone, acetone, and tetrahydrofuran, may be used. This is generally known as the prepolymer method.

[0068] When an acid group-containing diol is used as a raw material, the acid group of the prepolymer is neutralized using a substance that serves as a counter ion, such as an organic base such as N,N-dimethylethanolamine, N,N-diethylethanolamine, diethanolamine, triethanolamine, triisopropanolamine, trimethylamine, or triethylamine, or an inorganic base such as sodium hydroxide, potassium hydroxide, or ammonia. The dispersion stability of the polyurethane is improved by using a neutralizing agent that preferably contains an alkali metal such as sodium hydroxide or potassium hydroxide. The neutralizing agent is used in an amount of preferably 0.5 to 1.0 mol, more preferably 0.8 to 1.0 mol, per mol of the acid group of the prepolymer, to prevent viscosity increase and improve workability.

[0069] The prepolymer is then added to a liquid containing a chain extender or crosslinking agent to carry out a chain extension reaction or crosslinking reaction. If an organic solvent is used, it is removed using an evaporator or the like to obtain a dispersion of resin particles of the urethane resin.

[0070] As catalysts used in the polymerization reaction of polyurethane, titanium catalysts, aluminum catalysts, zirconium catalysts, antimony catalysts, germanium catalysts, bismuth catalysts and metal complex catalysts are preferable. In particular, titanium catalysts are preferably tetraalkyl titanates such as tetrabutyl titanate and tetramethyl titanate, and metal oxalates such as potassium titanium oxalate. Other catalysts are not particularly limited as long as they are known catalysts, and include tin compounds such as dibutyltin oxide and dibutyltin dilaurate. As non-heavy metal catalysts, it has long been known that acetylacetonate complexes of transition metals such as titanium, iron, copper, zirconium, nickel, cobalt, and manganese have urethane-forming activity. In recent years, due to the increasing environmental awareness, low-toxicity catalysts that can replace highly toxic heavy metal catalysts are desired, and the high urethane-forming activity of titanium / zirconium compounds has been utilized. In particular, in the field of soft packaging, since plastic films account for a large proportion of food applications, it is highly likely that highly toxic metal catalysts will no longer be usable.

[0071] 1.1.1.5. Acid value of urethane resin The acid value of the urethane resin contained in the aqueous resin liquid composition constituting the ink set according to this embodiment is 50 mgKOH / g or more and 100 mgKOH / g or less, preferably 60 mgKOH / g or more and 95 mgKOH / g or less, more preferably 65 mgKOH / g or more and 90 mgKOH / g or less, more preferably 70 mgKOH / g or more and 85 mgKOH / g or less, and particularly preferably 75 mgKOH / g or more and 85 mgKOH / g or less. If the acid value of the urethane resin is less than 50 mgKOH / g, the laminate peel strength tends to be poor. This is presumed to be because the effect of improving adhesion by the acid group is insufficient. On the other hand, even if the acid value of the urethane resin is higher than 100 mgKOH / g, the laminate peel strength tends to be poor. This is presumed to be because a high acid value makes it easier for water absorption and moisture absorption to occur, and the urethane resin swells with water. In terms of blocking resistance, a high acid value of the urethane resin tends to result in poorer performance, and a lower acid value is preferable. Therefore, by setting the acid value of the urethane resin to 50 mgKOH / g or more and 100 mgKOH / g or less, it is possible to achieve both excellent laminate peel strength and blocking resistance.

[0072] The acid value of the polyurethane can be measured by titration. The acid value is measured using a titration device such as "AT610" manufactured by Kyoto Electronics Manufacturing Co., Ltd., and calculated by applying the value to the following formula (1).

[0073] Acid value (mg / g)=(EP1-BL1)×FA1×C1×K1 / SIZE ···(1) (In the above formula (1), EP1 is the titration volume (mL), BL1 is the blank value (0.0mL), FA1 is the factor of the titrant (1.00), C1 is the concentration conversion value (5.611mg / mL) (equivalent to potassium hydroxide in 1mL of 0.1mo1 / L KOH), K1 is the coefficient (1), and SIZE is the sample size (g).)

[0074] For example, the measurement can be performed according to JIS K0070. As a titration reagent, an ethanol solution of sodium hydroxide can be used.

[0075] The acid value of the polyurethane can be changed by, for example, adjusting the content of the skeleton derived from a carboxyl group-containing glycol (an acid group-containing polyol such as dimethylolpropionic acid). In order to make the polyurethane more easily dispersible, it is preferable to use a carboxyl group-containing glycol to obtain a polyurethane having a carboxyl group.

[0076] The aqueous resin liquid composition constituting the ink set according to this embodiment may contain multiple types of resins made of the above-mentioned polyurethane (urethane resin) and polyurea (urea resin). The polyurethane may be added in the form of an emulsion.

[0077] 1.1.1.6. Resin content The aqueous resin liquid composition constituting the ink set according to this embodiment may contain a plurality of types of the above-mentioned resins. The content of the urethane resin in the resin liquid composition is preferably 1% by mass or more as solid content. It is also preferably 15% by mass or less. It is further preferably 1% by mass or more and 15% by mass or less, and more preferably 2% by mass or more and 10% by mass or less. It is particularly preferably 3% by mass or more and 7% by mass or less. When the content of the resin in the resin liquid composition is within the above range, it tends to be possible to exhibit good laminate peel strength and blocking resistance while maintaining an appropriate viscosity of the resin liquid composition.

[0078] 1.1.2.Water The aqueous resin liquid composition constituting the ink set according to this embodiment contains water. In the present invention, "aqueous" means that water is one of the main solvents. Water is the main medium of the resin liquid composition, and is a component that evaporates and disperses when dried. The water is preferably pure water such as ion-exchanged water, ultrafiltered water, reverse osmosis water, distilled water, or other pure water or ultrapure water from which ionic impurities have been removed as much as possible. In addition, it is preferable to use water sterilized by ultraviolet irradiation or addition of hydrogen peroxide, etc., since this can suppress the growth of mold and bacteria when the resin liquid composition is stored for a long period of time.

[0079] The water content in the resin liquid composition is preferably 40% by mass or more, more preferably 45% by mass or more, even more preferably 50% by mass or more, and particularly preferably 60% by mass or more. The upper limit is preferably 99% by mass or less.

[0080] 1.1.3. Organic Solvents The aqueous resin liquid composition constituting the ink set according to the present embodiment may contain an organic solvent. By containing an organic solvent, the resin liquid composition can have excellent ejection stability when used in an inkjet method, and can effectively suppress evaporation of water from a recording head when left unused for a long period of time.

[0081] The organic solvent used in the resin liquid composition is preferably a water-soluble organic solvent. By using a water-soluble organic solvent, the drying property of the resin liquid composition becomes better, and an image having excellent image quality and abrasion resistance can be obtained.

[0082] The water-soluble organic solvent is not particularly limited, but examples thereof include alkanediols, polyols, nitrogen-containing solvents, esters, glycol ethers, and cyclic esters.

[0083] Examples of alkanediols include 1,2-alkanediols such as 1,2-pentanediol, 1,2-hexanediol, 1,2-octanediol, and 1,6-hexanediol. These can be used alone or in combination of two or more. Alkanediols are excellent in increasing the wettability of the resin liquid composition to the recording medium and wetting it uniformly. Among these, 1,2-alkanediols are particularly preferred. Examples of alkanediols include diols of alkanes having 5 or more carbon atoms. The number of carbon atoms of the alkane is preferably 5 to 9, and may be either linear or branched. The content of the alkanediols in the resin liquid composition is preferably from 1% by mass to 20% by mass, more preferably from 1.5% by mass to 15% by mass, and even more preferably from 2% by mass to 10% by mass.

[0084] Examples of polyols include ethylene glycol, propylene glycol, 1,2-propanediol, 1,2-butanediol, 1,3-propanediol, 1,4-butanediol, diethylene glycol, triethylene glycol, dipropylene glycol, 2-ethyl-2-methyl-1,3-propanediol, 2-methyl-2-propyl-1,3-propanediol, 2-methyl-1,3-propanediol, 2,2-dimethyl-1,3-propanediol, 3-methyl-1,3-butanediol, 2-ethyl-1,3-hexanediol, 3-methyl-1,5-pentanediol, 2-methylpentane-2,4-diol, trimethylolpropane, and glycerin. They can be used alone or in combination of two or more. Polyols are excellent in their moisturizing properties. The polyols are preferably alkanes having 4 or less carbon atoms and having 2 or more hydroxyl groups, and alkanes having 4 or less carbon atoms and having 2 or more hydroxyl groups, intermolecularly condensed with each other. The condensation product preferably has a condensation number of 2 to 4. Here, the polyols are compounds having 2 or more hydroxyl groups in the molecule, and in this embodiment, the number of hydroxyl groups is preferably 2 or 3. The content of the polyols in the resin liquid composition is preferably 1% by mass or more and 30% by mass or less, more preferably 2% by mass or more and 20% by mass or less, and even more preferably 3% by mass or more and 10% by mass or less.

[0085] Examples of the nitrogen-containing solvent include pyrrolidones such as N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, N-vinyl-2-pyrrolidone, 2-pyrrolidone, N-butyl-2-pyrrolidone, and 5-methyl-2-pyrrolidone. These can be used alone or in combination of two or more. The nitrogen-containing solvent acts as a good dissolving agent for resins, and tends to produce a recording material with excellent abrasion resistance.

[0086] Examples of the nitrogen-containing solvent include alkoxyalkylamides, such as 3-methoxy-N,N-dimethylpropionamide, 3-methoxy-N,N-diethylpropionamide, 3-methoxy-N,N-methylethylpropionamide, 3-ethoxy-N,N-dimethylpropionamide, 3-ethoxy-N,N-diethylpropionamide, 3-ethoxy-N,N-methylethylpropionamide, 3-n-butoxy-N,N-dimethylpropionamide, 3-n-butoxy-N,N-diethylpropionamide, 3-n-butoxy-N,N-methylethylpropionamide, 3-n- Examples of the propoxy-N,N-dimethylpropionamide include 3-n-propoxy-N,N-diethylpropionamide, 3-n-propoxy-N,N-methylethylpropionamide, 3-iso-propoxy-N,N-dimethylpropionamide, 3-iso-propoxy-N,N-diethylpropionamide, 3-iso-propoxy-N,N-methylethylpropionamide, 3-tert-butoxy-N,N-dimethylpropionamide, 3-tert-butoxy-N,N-diethylpropionamide, and 3-tert-butoxy-N,N-methylethylpropionamide.

[0087] The nitrogen-containing solvent may also be an amide-based solvent. The amide-based solvent is preferably a cyclic amide-based solvent or a non-cyclic amide-based solvent. The cyclic amide-based solvent may be the above-mentioned pyrrolidones. The non-cyclic amide-based solvent may be the above-mentioned alkoxyalkylamides.

[0088] When the resin liquid composition contains a nitrogen-containing solvent, the content of the nitrogen-containing solvent in the resin liquid composition is preferably 1 mass % or more, more preferably 5 mass % or more, and even more preferably 10 mass % or more.

[0089] On the other hand, the content of the nitrogen-containing solvent in the resin liquid composition is preferably not more than 30% by mass (30% by mass or less), preferably not more than 20% by mass, preferably not more than 10% by mass, more preferably not more than 5% by mass, even more preferably not more than 1% by mass, and particularly preferably not containing a nitrogen-containing solvent. When the organic solvent contains a nitrogen-containing solvent, good film-forming properties of the resin liquid coating film on the recording medium can be obtained, but it can also cause the resin to dissolve and melt in the inkjet head, and in particular, in the case of a resin liquid composition that does not contain a high-boiling point solvent such as glycerin, water is easily evaporated and the resin is easily dissolved and melted. Therefore, when the content of the nitrogen-containing solvent in the resin liquid composition is within the above range, good clogging recovery properties tend to be obtained.

[0090] Examples of esters include glycol monoacetates such as ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol monobutyl ether acetate, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, propylene glycol monomethyl ether acetate, dipropylene glycol monomethyl ether acetate, and methoxybutyl acetate; Examples of glycol diesters include ethylene glycol diacetate, propylene glycol diacetate, dipropylene glycol diacetate, ethylene glycol acetate propionate, ethylene glycol acetate butyrate, diethylene glycol acetate butyrate, diethylene glycol acetate propionate, diethylene glycol acetate butyrate, propylene glycol acetate propionate, propylene glycol acetate butyrate, dipropylene glycol acetate butyrate, and dipropylene glycol acetate propionate.

[0091] The glycol ethers may be monoethers or diethers of alkylene glycols, and alkyl ethers are preferred. Specific examples include ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monoisopropyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, triethylene glycol monobutyl ether, tetraethylene glycol monomethyl ether, tetraethylene glycol monoethyl ether, tetraethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol monopropyl ... alkylene glycol monoalkyl ethers such as ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dibutyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol dibutyl ether, diethylene glycol methyl ethyl ether, diethylene glycol methyl butyl ether, triethylene glycol dimethyl ether, triethylene glycol diethyl ether, triethylene glycol dibutyl ether, triethylene glycol methyl butyl ether, tetraethylene glycol dimethyl ether, tetraethylene glycol diethyl ether, tetraethylene glycol dibutyl ether, propylene glycol dimethyl ether, propylene glycol diethyl ether, dipropylene glycol dimethyl ether, dipropylene glycol di Examples of the alkylene glycol dialkyl ether include alkylene glycol dialkyl ethers such as ethyl ether and tripropylene glycol dimethyl ether, which can control the wettability of the resin liquid composition to a recording medium.

[0092] In addition, among the glycol ethers, diethers tend to dissolve or swell the resin in the resin liquid composition more easily than monoethers, and are therefore more preferred in terms of improving the abrasion resistance of the formed image. On the other hand, monoethers are more preferred because they have better wet spreadability. In addition, the content of glycol ethers in the resin liquid composition is preferably 1% by mass or more and 30% by mass or less, more preferably 2% by mass or more and 20% by mass or less, and even more preferably 3% by mass or more and 10% by mass or less.

[0093] Examples of the cyclic esters include cyclic esters (lactones) such as β-propiolactone, γ-butyrolactone, δ-valerolactone, ε-caprolactone, β-butyrolactone, β-valerolactone, γ-valerolactone, β-hexanolactone, γ-hexanolactone, δ-hexanolactone, β-heptanolactone, γ-heptanolactone, δ-heptanolactone, ε-heptanolactone, γ-octanolactone, δ-octanolactone, ε-octanolactone, δ-nonalactone, ε-nonalactone, and ε-decanolactone, as well as compounds in which the hydrogen of the methylene group adjacent to the carbonyl group is substituted with an alkyl group having 1 to 4 carbon atoms.

[0094] The content of the organic solvent is preferably 1% by mass or more, more preferably 3% by mass or more, more preferably 5% by mass or more, even more preferably 10% by mass or more, and particularly preferably 15% by mass or more, based on the total mass of the resin liquid composition. The content of the organic solvent is preferably 40% by mass or less, more preferably 35% by mass or less, and even more preferably 30% by mass or less, based on the total mass of the resin liquid composition. Further, it is more preferably 25% by mass or less, and particularly preferably 23% by mass or less. When the content of the organic solvent is within the above range, the clogging recovery property and abrasion resistance of the resin liquid composition are more excellent, which is preferable.

[0095] The normal boiling point of the organic solvent is preferably 160° C. or higher, more preferably 180° C. or higher, and even more preferably 200° C. or higher. The normal boiling point of the organic solvent is preferably 280° C. or lower, more preferably 270° C. or lower, and even more preferably 250° C. or lower. When the normal boiling point of the organic solvent is within the above range, the resin liquid composition has better clogging recovery properties and abrasion resistance, which is preferable.

[0096] In addition, polyol-based organic solvents having a standard boiling point of more than 280°C, such as triethylene glycol and glycerin, function as moisturizing agents, and thus suppress the drying of the inkjet head when contained, resulting in excellent clogging recovery. On the other hand, polyol-based organic solvents having a standard boiling point of more than 280°C may absorb moisture from the resin liquid composition, thicken the resin liquid composition near the inkjet head, or reduce the drying property of the resin liquid composition when attached to a recording medium. For this reason, in this embodiment, the resin liquid composition preferably does not contain more than 1.0% by mass of polyol-based organic solvents having a standard boiling point of more than 280°C, more preferably does not contain more than 0.8% by mass, and particularly preferably does not contain more than 0.1% by mass, based on the total mass of the resin liquid composition. In this case, the drying property of the resin liquid composition on the recording medium is increased, making it particularly suitable for recording on a poorly absorbent recording medium, and an image with excellent abrasion resistance can be obtained. Furthermore, it is more preferable that the content of organic solvents having a standard boiling point of more than 280°C, not limited to polyols, is within the above range, because an image with excellent abrasion resistance can be obtained.

[0097] Surfactants The aqueous resin liquid composition constituting the ink set according to this embodiment contains a surfactant. The surfactant is not particularly limited, but examples thereof include acetylene glycol surfactants, fluorine-based surfactants, and silicone-based surfactants. It is preferable to contain at least one of these, and it is more preferable to contain an acetylene glycol surfactant or a silicone-based surfactant among these. By containing an acetylene glycol surfactant or a silicone-based surfactant in the resin liquid composition, the dynamic surface tension of the resin liquid composition tends to decrease, and the clogging recovery property tends to be improved.

[0098] The acetylene glycol surfactant is not particularly limited, but examples thereof include Surfynol 104, 104E, 104H, 104A, 104BC, 104DPM, 104PA, 104PG-50, 104S, 420, 440, 465, 485, SE, SE-F, 504, 61, DF37, CT111, CT121, CT131, CT136, TG, GA, and DF110D (all trade names, manufactured by Air Products Japan Co., Ltd.), O Examples of such surfactants include Rufin B, Y, P, A, STG, SPC, E1004, E1010, PD-001, PD-002W, PD-003, PD-004, EXP.4001, EXP.4036, EXP.4051, AF-103, AF-104, AK-02, SK-14, and AE-3 (all trade names, manufactured by Nissin Chemical Industry Co., Ltd.), and Acetylenol E00, E00P, E40, and E100 (all trade names, manufactured by Kawaken Fine Chemical Co., Ltd.).

[0099] The silicone surfactant is not particularly limited, but a polysiloxane compound is preferred. The polysiloxane compound is not particularly limited, but for example, a polyether-modified organosiloxane is exemplified. Examples of commercially available polyether-modified organosiloxanes include BYK-306, BYK-307, BYK-333, BYK-341, BYK-345, BYK-346, BYK-348 (all trade names, manufactured by BYK Japan Co., Ltd.), KF-351A, KF-352A, KF-353, KF-354L, KF-355A, KF-615A, KF-945, KF-640, KF-642, KF-643, KF-6020, X-22-4515, KF-6011, KF-6012, KF-6015, KF-6017 (all trade names, manufactured by Shin-Etsu Chemical Co., Ltd.), Silface SAG503A, Silface SAG014 (all trade names, manufactured by Nissin Chemical Industry Co., Ltd.), and the like.

[0100] As the fluorosurfactant, it is preferable to use a fluorine-modified polymer, and a specific example thereof is BYK-340 (product name, manufactured by BYK Japan KK).

[0101] When the surfactant is contained, the content thereof is preferably 0.1% by mass or more and 1.5% by mass or less based on the total mass of the resin liquid composition.

[0102] 1.1.5. pH Adjusters In this embodiment, the resin liquid composition preferably contains a pH adjuster for the purpose of adjusting the pH. The pH adjuster is not particularly limited, but may be an acid, a base, a weak acid, a weak base, or a suitable combination thereof, for example, a tertiary alkanolamine such as triethanolamine or triisopropanolamine. When a pH adjuster is added, for example, the total amount of the resin liquid composition is preferably 0.01% by mass or more and 2% by mass or less, more preferably 0.1% by mass or more and 1% by mass or less, and even more preferably 0.2% by mass or more and 0.5% by mass or less.

[0103] Chelating agents In this embodiment, a suitable amount of a chelating agent may be added to the resin liquid composition in order to remove unnecessary ions in the resin liquid composition. Examples of the chelating agent include disodium dihydrogen ethylenediaminetetraacetate, or ethylenediamine nitrilotriacetate, hexametaphosphate, pyrophosphate, or metaphosphate, and other ethylenediaminetetraacetic acid salts and salts thereof. In the case where a chelating agent is added, the amount may be 0.01% by mass or more and 1% by mass or less with respect to the total amount of the resin liquid composition.

[0104] 1.1.7. Preservatives and antifungal agents In this embodiment, a preservative and an antifungal agent may be appropriately added to the resin liquid composition. Examples of the preservative and the antifungal agent include sodium benzoate, sodium pentachlorophenol, sodium 2-pyridinethiol-1-oxide, sodium sorbate, sodium dehydroacetate, 1,2-dibenzisothiazolin-3-one such as Proxel CRL, BDN, GXL, XL-2, TN, and LV sold by Lonza Japan Co., Ltd., and 4-chloro-3-methylphenol such as Preventol (registered trademark) CMK sold by Bayer Holding Ltd.

[0105] 1.1.8. Other components of the resin liquid composition The resin liquid composition may further contain, as components other than those described above, additives that can be typically used in inkjet inks, such as a rust inhibitor such as benzotriazole, an antioxidant, an ultraviolet absorber, an oxygen absorber, a dissolution aid, etc.

[0106] The resin liquid composition is not a composition used for coloring a recording medium, such as an ink composition described later. Therefore, the content of a coloring material such as a pigment in the resin liquid composition is preferably 0.2% by mass or less, more preferably 0.1% by mass or less, even more preferably 0.05% by mass or less, particularly preferably 0.01% by mass or less, and may be 0% by mass.

[0107] 1.1.9. Method for producing liquid resin composition The method for producing the aqueous resin liquid composition constituting the ink set according to this embodiment is not particularly limited, but it can be produced, for example, as follows. The resin particle dispersion or resin solution and the components of each of the above-mentioned resin liquid compositions are mixed in any order, and impurities are removed by filtration or the like as necessary. As a method for mixing each component, a method in which the materials are added sequentially to a container equipped with a stirring device such as a mechanical stirrer or a magnetic stirrer, and the materials are stirred and mixed is preferably used.

[0108] 1.1.10. Physical properties of resin liquid composition

[0109] From the viewpoint of the balance between image quality and reliability as an ink for inkjet recording, the aqueous resin liquid composition constituting the ink set according to this embodiment preferably has a surface tension of 20 mN / m to 40 mN / m, and more preferably 20 mN / m to 35 mN / m at 20° C. The surface tension can be measured, for example, by using an automatic surface tensiometer CBVP-Z (product name, manufactured by Kyowa Interface Science Co., Ltd.) to confirm the surface tension when a platinum plate is wetted with the resin liquid composition in an environment of 20° C.

[0110] From the same viewpoint, the viscosity of the aqueous resin liquid composition constituting the ink set according to this embodiment at 20° C. is preferably 1.5 mPa·s or more and 5.0 mPa·s or less, and more preferably 1.5 mPa·s or more and 3.6 mPa·s or less. The viscosity can be measured, for example, using a viscoelasticity tester MCR-300 (product name, manufactured by Pysica) in an environment of 20° C.

[0111] 1.2. Colored ink composition The colored ink composition, which is a water-based inkjet ink that constitutes the ink set according to this embodiment, contains a pigment.

[0112] The color ink composition contains a pigment and has an alicyclic structure or an aromatic ring structure. Except that it is not necessary to contain the urethane resin having a concentration of 100 mgKOH / g, it may contain the same components as the resin liquid composition, and the contents thereof may be similar.

[0113] As the pigment, either an organic pigment or an inorganic pigment can be used. There is no limitation on the pigment contained in the colored ink composition, and any color pigment of a white pigment or a non-white pigment (yellow, cyan, magenta, black, etc.) can be used.

[0114] In this way, any color pigment may be used in the color ink composition, and therefore the color ink composition constituting the ink set according to this embodiment may comprise a white ink containing a white pigment and a non-white ink containing a non-white pigment. According to the ink set according to this embodiment, even when both a white ink and a non-white ink are included, it is possible to achieve both excellent laminate peel strength and blocking resistance of the recorded matter, and excellent clogging recovery properties.

[0115] On the other hand, as described above, when the pigment contained in the color ink composition is a white pigment, the laminate peel strength, blocking resistance, and clogging recovery properties are particularly poor. According to the ink set according to this embodiment, even with such a white ink, it is possible to achieve both excellent laminate peel strength and blocking resistance and excellent clogging recovery properties, and from the viewpoint of being able to enjoy the effects of the present invention more effectively, it is more preferable that the color ink composition is a white ink containing a white pigment.

[0116] Hereinafter, each component contained in the colored ink composition will be described separately for the white ink and the non-white ink.

[0117] 1.2.1.White ink The white ink contains a white pigment. The components contained in the white ink will be described below.

[0118] 1.2.1.1. White pigment In this embodiment, examples of white pigments for white ink include CI Pigment White 1, which is basic lead carbonate, CI Pigment White 4, which is made of zinc oxide, CI Pigment White 5, which is made of a mixture of zinc sulfide and barium sulfate, CI Pigment White 6, which is made of titanium dioxide, CI Pigment White 6:1, which is made of titanium dioxide containing other metal oxides, CI Pigment White 7, which is made of zinc sulfide, CI Pigment White 18, which is made of calcium carbonate, CI Pigment White 19, which is made of clay, CI Pigment White 20, which is made of titanium mica, CI Pigment White 21, which is made of barium sulfate, CI Pigment White 22, which is made of gypsum, CI Pigment White 26, which is made of magnesium oxide and silicon dioxide, CI Pigment White 27, which is made of silicon dioxide, and CI Pigment White 28, which is made of anhydrous calcium silicate. Among these, it is preferable to use CI Pigment White 6, which has excellent color development and hiding power.

[0119] The average particle size of the white pigment is preferably 100 μm or more and 500 μm or less, more preferably 50 μm or more and 450 μm or less, and even more preferably 200 μm or more and 400 μm or less. By making the average particle size of the white pigment within this range, ejection stability from an inkjet head tends to be ensured. In addition, hiding power tends to be improved.

[0120] In this specification, unless otherwise specified, the "average particle size" refers to the cumulative distribution of This refers to the volume-based particle size distribution, which is the particle size at 0 vol%. The average particle size is measured by the dynamic light scattering method or the laser diffraction method described in JIS Z8825. Specifically, a particle size distribution meter that uses the dynamic light scattering method as the measurement principle (for example, "Microtrac UPA" manufactured by Nikkiso Co., Ltd.) can be used.

[0121] In this specification, the term "white" when referring to white ink, white pigment, etc. does not refer only to perfect white, but also includes chromatic and achromatic colors that are slightly colored or glossy, as long as they are visible as white. For example, in CIELAB, a color with L* of 80 or more and a* and b* of ±10 or less is preferable. Furthermore, a color with L* of 90 or more and a* and b* of ±50 or less is preferable.

[0122] The content (solid content) of the white pigment in the white ink is 5% by mass to 20% by mass, preferably 7% by mass to 20% by mass, more preferably 9% by mass to 15% by mass, and even more preferably 12% by mass to 15% by mass. If the content of the white pigment is within the above range, nozzle clogging of the inkjet recording device is unlikely to occur, and hiding properties such as whiteness can be fully satisfied.

[0123] Dispersants It is preferable that the white pigment can be stably dispersed in water, and therefore a dispersant may be used for dispersion. The dispersant may be any of a surfactant, a resin dispersant, etc., and is selected from those that can improve the dispersion stability of the white pigment in the white ink. The white pigment may also be used as a self-dispersing pigment by modifying the surface of the pigment particles by oxidizing or sulfonating the pigment surface with, for example, ozone, hypochlorous acid, fuming sulfuric acid, etc.

[0124] Examples of the resin dispersant include (meth)acrylic resins and salts thereof, such as poly(meth)acrylic acid, (meth)acrylic acid-acrylonitrile copolymer, (meth)acrylic acid-(meth)acrylic acid ester copolymer, vinyl acetate-(meth)acrylic acid ester copolymer, vinyl acetate-(meth)acrylic acid copolymer, and vinylnaphthalene-(meth)acrylic acid copolymer; styrene-(meth)acrylic acid copolymer, styrene-(meth)acrylic acid-(meth)acrylic acid ester copolymer, styrene-α-methylstyrene-(meth)acrylic acid copolymer, and styrene-α-methylstyrene-(meth)acrylic acid copolymer. Examples of the water-soluble resins include styrene resins and salts thereof, such as styrene-based (meth)acrylic acid ester copolymers, styrene-maleic acid copolymers, and styrene-maleic anhydride copolymers; urethane resins and salts thereof, which are polymeric compounds (resins) containing urethane bonds formed by the reaction of an isocyanate group and a hydroxyl group and may be linear and / or branched, and may have a crosslinked structure; polyvinyl alcohols; vinyl naphthalene-maleic acid copolymers and salts thereof; vinyl acetate-maleic acid ester copolymers and salts thereof; and vinyl acetate-crotonic acid copolymers and salts thereof. Among these, preferred are copolymers of a monomer having a hydrophobic functional group and a monomer having a hydrophilic functional group, and polymers made of a monomer having both a hydrophobic functional group and a hydrophilic functional group. The copolymers may be in the form of any of random copolymers, block copolymers, alternating copolymers, and graft copolymers.

[0125] Commercially available styrene-based resin dispersants include, for example, X-200, X-1, X-205, X-220, and X-228 (manufactured by Seiko PMC Corporation), Nopcosperse (registered trademark) 6100 and 6110 (manufactured by San Nopco Ltd.), Joncryl 67, 586, 611, 678, 680, 682, and 819 (manufactured by BASF), DISPERBYK-190 (manufactured by BYK Japan KK), N-EA137, N-EA157, N-EA167, N-EA177, N-EA197D, N-EA207D, and E-EN10 (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.).

[0126] Commercially available acrylic resin dispersants include BYK-187, BYK-190, BYK-191, BYK-194N, and BYK-199 (manufactured by BYK-Chemie Co., Ltd.), Aron A-210, A6114, AS-1100, AS-1800, A-30SL, A-7250, and CL-2 (manufactured by Toagosei Co., Ltd.).

[0127] Further, commercially available urethane resin dispersants include BYK-182, BYK-183, BYK-184, BYK-185 (manufactured by BYK-Chemie Co., Ltd.), TEGO Disperse710 (manufactured by Evonic Tego Chemi), Borchi (registered trademark) Gen1350 (manufactured by OMG Borschers), and the like.

[0128] The dispersant may be used alone or in combination of two or more. The total content of the dispersant is preferably 0.1 to 30 parts by mass, more preferably 0.5 to 25 parts by mass, even more preferably 1 to 20 parts by mass, and even more preferably 1.5 to 15 parts by mass, relative to 60 parts by mass of the white pigment. By having the content of the dispersant in the above range or more, the dispersion stability of the white pigment can be further improved. In addition, if the content of the dispersant is in the above range or less, the viscosity of the obtained dispersion can be kept low.

[0129] Among the above-listed dispersants, it is more preferable to use a resin dispersant, particularly at least one selected from acrylic resins, styrene resins, and urethane resins. In this case, it is more preferable that the weight average molecular weight of the dispersant is 500 or more. By using such a resin dispersant as a dispersant, it is possible to reduce odor and further improve the dispersion stability of the white pigment.

[0130] 1.2.1.3.Water The white ink contains water, which is similar to that of the resin liquid composition and will not be described further.

[0131] Resin The white ink may contain a resin other than the urethane resin contained in the resin liquid composition described above. By containing a resin in the white ink, the adhesion of the image formed by the white ink adhered to the recording medium can be improved, and blocking resistance may be improved.

[0132] Examples of resins other than the urethane resin contained in the above-mentioned resin liquid composition include urethane-based resins, acrylic-based resins, fluorene-based resins, polyolefin-based resins, rosin-modified resins, terpene-based resins, polyester-based resins, polyamide-based resins, epoxy-based resins, vinyl chloride-based resins, vinyl chloride-vinyl acetate copolymers, ethylene-vinyl acetate-based resins, etc. These resins are often handled in the form of emulsion, but may also be in the form of powder. In addition, the resins may be used alone or in combination of two or more.

[0133] The urethane resin is a general term for resins having a urethane bond. In addition to the urethane bond, the urethane resin may be a polyether type urethane resin containing an ether bond in the main chain, a polyester type urethane resin containing an ester bond in the main chain, or a polycarbonate type urethane resin containing a carbonate bond in the main chain. As the urethane resin, a commercially available product may be used, for example, Superflex 460, 460s, 840, E-4000 (trade names, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), Resamine D-1060, D-2020, D-4080, D-4200, D-6300, D-6455 (trade names, manufactured by Dainichi Seiyaku Chemicals Co., Ltd.), Takelac WS-6021, W-512-A-6 (trade names, manufactured by Mitsui Chemicals Polyurethanes, Inc.), etc. Alternatively, it may be selected from commercially available products such as SANKYU 2710 (trade name, manufactured by LUBRIZOL), and PERMALIN UA-150 (trade name, manufactured by SANYO CHEMICAL INDUSTRIES, LTD.).

[0134] Acrylic resin is a general term for polymers obtained by polymerizing at least an acrylic monomer such as (meth)acrylic acid or a (meth)acrylic acid ester as one component, and examples thereof include resins obtained from acrylic monomers and copolymers of acrylic monomers and other monomers. Examples thereof include acrylic-vinyl resins, which are copolymers of acrylic monomers and vinyl monomers. Further examples thereof include copolymers with vinyl monomers such as styrene.

[0135] As the acrylic monomer, acrylamide, acrylonitrile, etc. can also be used. For the resin emulsion using an acrylic resin as a raw material, a commercially available product may be used, and may be selected from, for example, FK-854 (trade name, manufactured by Chuo Rika Kogyo Co., Ltd.), Mowinyl 952B, 718A (trade names, manufactured by Nippon Synthetic Chemical Industry Co., Ltd.), Nipol LX852, LX874 (trade names, manufactured by Nippon Zeon Co., Ltd.), etc.

[0136] In this specification, the acrylic resin may be a styrene-acrylic resin. In addition, in this specification, the term "(meth)acrylic" means at least one of acrylic and methacrylic.

[0137] Styrene-acrylic resins are copolymers obtained from styrene monomers and acrylic monomers, and examples thereof include styrene-acrylic acid copolymers, styrene-methacrylic acid copolymers, styrene-methacrylic acid-acrylate copolymers, styrene-α-methylstyrene-acrylic acid copolymers, and styrene-α-methylstyrene-acrylic acid-acrylate copolymers. The styrene-acrylic resin may be a commercially available product, and may be selected from, for example, JONCRYL 62J, 7100, 390, 711, 511, 7001, 632, 741, 450, 840, 74J, HRC-1645J, 734, 852, 7600, 775, 537J, 1535, PDX-7630A, 352J, 352D, PDX-7145, 538J, 7640, 7641, 631, 790, 780, 7610 (trade names, manufactured by BASF), Mowinyl 966A, 975N (trade names, manufactured by Nippon Synthetic Chemical Industry Co., Ltd.), Vinyblan 2586 (manufactured by Nissin Chemical Industry Co., Ltd.), and the like.

[0138] The polyolefin resin has an olefin such as ethylene, propylene, butylene, etc. in the structural skeleton, and a known one can be appropriately selected and used. As the olefin resin, a commercially available product can be used, and for example, it may be selected from among Arrowbase CB-1200, CD-1200 (product name, manufactured by Unitika Ltd.), etc.

[0139] Among these resins, it is preferable that the white ink contains an acrylic resin, since the white ink contains an acrylic resin, which tends to improve the adhesion of the image formed by the ink adhered to the recording medium, and tends to improve blocking resistance.

[0140] The resin may be supplied in the form of an emulsion. Examples of commercially available resin emulsions include Microgel E-1002 and E-5002 (product names of Nippon Paint Co., Ltd., styrene-acrylic resin emulsions), Boncoat 4001 (product name of DIC Corporation, acrylic resin emulsion), Boncoat 5454 (product name of DIC Corporation, styrene-acrylic resin emulsion), Polysol AM-710, AM-920, AM-2300, AP-4735, AT-860, PSASE-4210E (acrylic resin emulsion), Polysol AP-7020 (styrene-acrylic resin emulsion), Polysol SH-502 (vinyl acetate resin emulsion), Polysol AD-13, AD-2 , AD-10, AD-96, AD-17, AD-70 (ethylene-vinyl acetate resin emulsion), Polyzol PSASE-6010 (ethylene-vinyl acetate resin emulsion) (trade name, manufactured by Showa Denko KK), Polyzol SAE1014 (trade name, styrene-acrylic resin emulsion, manufactured by Nippon Zeon Co., Ltd.), Cybinol SK-200 (trade name, acrylic resin emulsion, manufactured by Cyden Chemical Co., Ltd.), AE-120A (trade name, acrylic resin emulsion, manufactured by JSR Corporation), AE373D (trade name, carboxy-modified styrene-acrylic resin emulsion, manufactured by E-Tech Co., Ltd.), Seikadine 1900W (trade name, ethylene-vinyl acetate resin emulsion, manufactured by Dainichi Seika Kogyo Co., Ltd.), Vinibran 2682 (acrylic resin emulsion), Vinibran 2886 (vinyl acetate-acrylic resin emulsion), Vinibran 5202 (acrylic acetate resin emulsion) (trade name, manufactured by Nissin Chemical Industry Co., Ltd.), Elitel KA-5071S, KT-8803, KT-9204, KT-8701, KT-8904, KT-0507 (trade name, polyester resin emulsion, manufactured by Unitika Ltd.), Hi-Tech SN-2002 (trade name, polyester resin emulsion, manufactured by Toho Chemical Co., Ltd.), Takelac W-6020, W-635, W-6061, W-605, W-635, W-6021 (trade name, urethane resin emulsion, manufactured by Mitsui Chemicals Polyurethane Co., Ltd.), Superflex 870, 800, 150, 420, 460, 470, 610, 700 (trade name, urethane resin emulsion, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), Permalin UA-150 (manufactured by Sanyo Chemical Industries, Ltd., urethane resin emulsion), Sun Cure 2710 (manufactured by Nippon Lubrizol Corporation, urethane resin emulsion), NeoRez R-9660, R-9637, R-940 (manufactured by Kusumoto Chemicals, Ltd., urethane resin emulsion), Adeka Bon Titer HUX-380,290K (ADEKA Corporation, urethane resin emulsion), Mowinyl 966A, Mowinyl 7320 (Nippon Synthetic Chemical Industry Co., Ltd.), Joncryl 7100, 390, 711, 511, 7001, 632, 741, 450, 840, 74J, HRC-1645J, 734, 852, 7600, 775, 537J, 1535, PDX-7630A , 352J, 352D, PDX-7145, 538J, 7640, 7641, 631, 790, 780, 7610 (all manufactured by BASF), NK Binder R-5HN (manufactured by Shin-Nakamura Chemical Co., Ltd.), Hydran WLS-210 (non-crosslinked polyurethane: manufactured by DIC Corporation), Joncryl 7610 (manufactured by BASF), etc. may be selected and used.

[0141] The glass transition temperature (Tg) of the resin is preferably -50.0°C or more and 200.0°C or less, more preferably 0.0°C or more and 150.0°C or less, and even more preferably 50.0°C or more and 100.0°C or less. When the glass transition temperature (Tg) of the resin is within the above range, the durability and clogging resistance tend to be more excellent. The glass transition temperature is measured, for example, using a differential scanning calorimeter "DSC7000" manufactured by Hitachi High-Tech Science Corporation in accordance with JIS K7121 (Method of measuring transition temperature of plastics).

[0142] The Tg of the resin can be adjusted by adjusting the type and composition ratio of the monomers during resin polymerization, focusing on the individual Tg of each monomer used. This allows the adjustment of the Tg of the entire resin. The acid value of the resin can also be adjusted by adjusting the type and composition ratio of the monomers, and this allows the adjustment of the adhesion between the resin and the recording medium. The coagulation property of the white ink can be adjusted by considering the coagulation property of each substance such as the resin, white pigment, and pigment dispersant, and the coagulation properties that are correlated with each other.

[0143] When a resin is contained in the white ink, the content, in terms of solid content, relative to the total mass of the white ink, is from 0.1% to 20.0% by mass, preferably from 1.0% to 15.0% by mass, and more preferably from 2.0% to 10.0% by mass.

[0144] 1.2.1.5.Other components of white ink White ink contains organic solvents, surfactants, pH adjusters, chelating agents, preservatives, antifungal agents, rust inhibitors, antioxidants, UV absorbers, oxygen absorbers, dissolving agents, and other additives. These components are the same as those in the liquid resin composition, and therefore the description thereof will be omitted.

[0145] 1.2.1.6. Manufacturing method and properties of white ink The method for producing the white ink is the same as that for the resin liquid composition, and therefore a description thereof will be omitted.

[0146] From the viewpoint of further improving clogging recovery properties, the viscosity of the white ink at 20°C is preferably from 1.5 mPa·s to 15.0 mPa·s, more preferably from 1.5 mPa·s to 5.0 mPa·s, and even more preferably from 1.5 mPa·s to 3.6 mPa·s.

[0147] The surface tension of the white ink at 25.0° C. is preferably 40.0 mN / m or less, preferably 38.0 mN / m or less, more preferably 35.0 mN / m or less, and even more preferably 30.0 mN / m or less. The surface tension can be measured by checking the surface tension when a platinum plate is wetted with the composition in an environment of 25.0° C. using an automatic surface tensiometer CBVP-Z (manufactured by Kyowa Interface Science Co., Ltd.).

[0148] 1.2.2.Non-white ink The non-white ink contains a non-white pigment. The components contained in the non-white ink are described below.

[0149] 1.2.2.1.Non-white pigments The non-white pigment contained in the non-white ink refers to a pigment other than the above-mentioned white pigment. The non-white pigment is preferably a color pigment such as cyan, yellow, magenta, or black. The pigment has excellent storage stability such as light resistance, weather resistance, and gas resistance, and from this viewpoint, it is preferable that the pigment is an organic pigment.

[0150] Specifically, the pigment may be an insoluble azo pigment, a condensed azo pigment, an azo lake, a chelate azo pigment, or other azo pigment, a phthalocyanine pigment, a perylene and perinone pigment, an anthraquinone pigment, a quinacridone pigment, a dioxane pigment, a thioindigo pigment, an isoindolinone pigment, a polycyclic pigment such as a quinophthalone pigment, a dye chelate, a dye lake, a nitro pigment, a nitroso pigment, an aniline black, a daylight fluorescent pigment, or a carbon black. The above pigments may be used alone or in combination of two or more. Furthermore, a glittering pigment may be used as a non-white pigment.

[0151] Specific examples of pigments include, but are not limited to, the following:

[0152] Examples of black pigments include No. 2300, No. 900, MCF88, No. 33, No. 40, No. 45, No. 52, MA7, MA8, MA100, No. 2200B, etc. (all manufactured by Mitsubishi Chemical Corporation), Raven 5750, Raven 5250, Raven 5000, Raven 3500, Raven 1255, Raven 700, etc. (all manufactured by Carbon Columbia), Rega1 400R, Rega1 330R, Rega1 660R, Mogul L, Monarch 700, Monarch 800, Monarch 880, Monarch 900, Monarch 1000, Monarch 1100, Monarch 1300, Monarch 1400, etc. (manufactured by CABOT JAPAN Co., Ltd.). KK)), Color Black FW1, Color Black FW2, Color Black FW2V, Color Black FW18, Color Black FW200, Color B1ack S150, Color Black S160, Color Black S170, Printex 35, Printex U, Printex Examples of carbon blacks include Special Black 6, Special Black 5, Special Black 4A, and Special Black 4 (all manufactured by Degussa).

[0153] Examples of yellow pigments include CI Pigment Yellow 1, 2, 3, 4, 5, 6, 7, 10, 11, 12, 13, 14, 16, 17, 24, 34, 35, 37, 53, 55, 65, 73, 74, 75, 81, 83, 93, 94, 95, 97, 98, 99, 108, 109, 110, 113, 114, 117, 120, 124, 128, 129, 133, 138, 139, 147, 151, 153, 154, 167, 172, and 180.

[0154] Examples of magenta pigments include CI Pigment Red 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 14, 15, 16, 17, 18, 19, 21, 22, 23, 30, 31, 32, 37, 38, 40, 41, 42, 48(Ca), 48(Mn), 57(Ca), 57:1, 88, 112, 114, 122, 123, 144, 146, 149, 150, 166, 168, 170, 171, 175, 176, 177, 178, 179, 184, 185, 187, 202, 209, 219, 224, 245, and CI Pigment Violet. 19, 23, 32, 33, 36, 38, 43, and 50.

[0155] Cyan pigments include, for example, CI Pigment Blue 1, 2, 3, 15, 15:1, 15:2, 15:3, 15:34, 15:4, 16, 18, 22, 25, 60, 65, and 66, and CI Vat Blue 4 and 60.

[0156] In addition, pigments other than magenta, cyan, and yellow are not particularly limited, but examples thereof include CI Pigment Green 7, 10, CI Pigment Brown 3, 5, 25, 26, and CI Pigment Orange 1, 2, 5, 7, 13, 14, 15, 16, 24, 34, 36, 38, 40, 43, and 63.

[0157] The pearl pigment is not particularly limited, but examples thereof include pigments having a pearlescent luster or an interference luster, such as titanium dioxide-coated mica, fish scale foil, and bismuth oxychloride.

[0158] The metallic pigment is not particularly limited, but examples thereof include particles of a simple substance such as aluminum, silver, gold, platinum, nickel, chromium, tin, zinc, indium, titanium, copper, or an alloy thereof.

[0159] The non-white pigment is preferably one that can be stably dispersed or dissolved in water, and may be dispersed using a dispersant as necessary. Examples of the dispersant include the same dispersants used to improve the dispersibility of the white pigment in the white ink described above.

[0160] The content of the non-white pigment is preferably from 0.3% to 20.0% by mass, more preferably from 0.5% to 15.0% by mass, even more preferably from 1% to 10% by mass, and particularly preferably from 2% to 5% by mass. The non-white pigment contained in the non-white ink may have either a high or low coagulation property, but a high coagulation property is preferred in terms of better bleeding resistance and the like.

[0161] The average particle size of the non-white pigment particles is preferably 10.0 nm or more and 200.0 nm or less, more preferably 30.0 nm or more and 200.0 nm or less, even more preferably 50.0 nm or more and 150.0 nm or less, and particularly preferably 70.0 nm or more and 120.0 nm or less. When the average particle size is within the above range, it is easy to obtain the desired pigment, and the pigment properties are preferable. This is preferable because it is easy to use.

[0162] Resin The non-white ink may contain a resin other than the urethane resin contained in the resin liquid composition described above. By containing a resin other than the urethane resin contained in the resin liquid composition, the non-white ink can improve the adhesion of the image formed by the ink attached to the recording medium, and blocking resistance may be improved. In addition, the non-white ink may contain the urethane resin contained in the resin liquid composition described above.

[0163] The resins contained in the liquid resin composition other than the urethane resin are the same as those described above, and therefore the description thereof will be omitted.

[0164] 1.2.2.3.Other components of non-white ink In addition to the non-white pigment, the non-white ink contains water and may contain other components such as organic solvents, surfactants, pH adjusters, chelating agents, preservatives, antifungal agents, rust inhibitors, antioxidants, UV absorbers, oxygen absorbers, dissolution aids, and other additives. These components are the same as those in the resin liquid composition, and so a description thereof will be omitted.

[0165] 1.2.2.4. Manufacturing method and properties of non-white ink The method for producing the non-white ink is the same as that for the resin liquid composition, and therefore a description thereof will be omitted.

[0166] From the viewpoint of further improving clogging recovery properties, the viscosity of the non-white ink at 20°C is preferably from 1.5 mPa·s to 15.0 mPa·s, more preferably from 1.5 mPa·s to 5.0 mPa·s, and even more preferably from 1.5 mPa·s to 3.6 mPa·s.

[0167] From the viewpoint of ensuring appropriate wetting and spreading properties on a recording medium, the non-white ink preferably has a surface tension of 40.0 mN / m or less, preferably 38.0 mN / m or less, more preferably 35.0 mN / m or less, and even more preferably 30.0 mN / m or less at 25.0° C. The surface tension is measured in the same manner as for the white ink.

[0168] 1.3. Printed matter using the ink set The ink set according to this embodiment can be suitably used for recording on a recording medium by the recording method described below.

[0169] The recording medium is not particularly limited, and may be an absorbent recording medium, a low absorbent recording medium, or a non-absorbent recording medium. Examples of the absorbent recording medium include absorbent paper and cloth.

[0170] Among these, low-absorption recording media or non-absorption recording media are preferred. With the ink set according to this embodiment, there is a tendency that recorded matter having excellent laminate peel strength and blocking resistance can be obtained even on such low-absorption recording media or non-absorption recording media.

[0171] In the present invention, a low-absorption recording medium or a non-absorption recording medium refers to a recording medium that does not absorb at all or hardly absorbs a resin liquid composition and a colored ink composition (hereinafter, both may be collectively referred to as "ink"). Quantitatively, the recording medium used in the present embodiment is a recording medium that "absorbs a small amount of ink within 30 msec from the start of contact in the Bristow method." 1 / 2 Water absorption up to 10mL / m 2 The Bristow method is the most widely used method for measuring the amount of liquid absorbed in a short period of time. This method has also been adopted by the Japan Tappi Technical Association. Details of the test method are described in Standard No. 51 "Paper and Paperboard - Liquid Absorbency Test Method - Bristow Method" of the "Japan Tappi Paper and Pulp Test Method 2000 Edition." Examples of recording media with this type of non-absorbent property include recording media that do not have an ink-receiving layer with ink absorbency on the recording surface, and recording media that have a coating layer with low ink absorbency on the recording surface.

[0172] The non-absorbing recording medium is not particularly limited, but examples thereof include a plastic film having no ink absorbing layer, a substrate such as paper coated with plastic, or a substrate having a plastic film adhered thereto, etc. Examples of plastics include polyvinyl chloride, polyethylene terephthalate, polycarbonate, polystyrene, polyurethane, polyethylene, polypropylene, etc.

[0173] The low-absorption recording medium is not particularly limited, but may be, for example, coated paper having a coating layer on the surface for receiving ink. The coated paper is not particularly limited, but may be, for example, printing paper such as art paper, coated paper, and matte paper.

[0174] Among these recording media, non-absorbent recording media mainly composed of polyolefin (polyethylene, polypropylene, etc.) and polyethylene terephthalate (PET) tend to be inferior in abrasion resistance and laminate peel strength, particularly non-absorbent recording media mainly composed of polyolefin. According to the ink set according to the present embodiment, even with such recording media, a recorded matter excellent in laminate peel strength and blocking resistance can be obtained, and from the viewpoint of enjoying the effects of the present invention, it is preferable to use these recording media.

[0175] Furthermore, from the viewpoint of enjoying the effects of the present invention, it is preferable that the ink set according to this embodiment be used after a recorded matter recorded using the ink set is subjected to a sealant film treatment on the recorded surface.

[0176] In the present invention, the term "sealant film treatment" refers to a treatment in which, after an image is formed on a recording medium, a sheet is adhered to at least the portion of the recording medium on which the image is formed. In this specification, the sheet used in the sealant film treatment may be referred to as a "laminating sheet" or simply as a "sheet". The sheet has, for example, a substrate and an adhesive layer. In addition to the substrate and the adhesive layer, the sheet may have a layer that exhibits another function. The laminating sheet may be provided on both sides of the recording medium, which can further enhance the effect of protecting the recording medium and the image.

[0177] Generally, when the sheet is used for thermal lamination, the adhesive layer (sometimes called glue layer, sealant layer, etc.) is made of a thermoplastic resin, which is softened and melted by heating to form a paste, which is then pressed onto the adherend. Examples of such thermoplastic resins include polyolefin resins such as polypropylene, low-density polyethylene (LDPE), linear low-density polyethylene, ethylene-vinyl acetate copolymer (EVA), ethylene-(meth)acrylic acid copolymer, ethylene-(meth)acrylic acid ester copolymer, ionomer resin (IO), ethylene-α-olefin copolymer, and amorphous polyester, polyester resins, and modified products thereof. The thickness of the adhesive layer can be, for example, 15 μm or more and 100 μm or less. The thermoplastic resin may be applied to the recording surface of the recording material.

[0178] The laminating sheet may be a commercially available one, but it may be produced by forming a substrate and an adhesive layer using a commonly used method such as tandem extrusion lamination, sandwich extrusion lamination, dry lamination, etc. In this case, the processing temperature is The temperature is preferably 150 to 300° C., and more preferably 200 to 280° C. In such processing, for example, an operation such as ozone treatment may be added between the substrate and the adhesive layer.

[0179] 2. Recording method A recording method according to one embodiment of the present invention includes a color ink composition applying step of applying the color ink composition to a recording medium by an inkjet method, and a resin liquid composition applying step of applying the resin liquid composition to the recording medium.

[0180] The recording method according to this embodiment is a method of ejecting the colored ink composition and the resin liquid composition constituting the ink set according to one embodiment of the present invention from an inkjet recording head to record an image on a recording medium. According to this recording method, it is possible to achieve both excellent recovery from nozzle clogging and excellent laminate peel strength and blocking resistance of the recorded matter.

[0181] An example of the recording method according to this embodiment will be described below in the order of the inkjet recording apparatus, the inkjet recording method, and each step of the recording method.

[0182] 2.1. Inkjet recording device An example of an inkjet recording apparatus in which the recording method according to the present embodiment is implemented will be described with reference to the drawings.

[0183] Fig. 1 is a schematic cross-sectional view showing the configuration of an inkjet recording device. Fig. 2 is a perspective view showing an example of the configuration of the periphery of a carriage of an inkjet recording device. As shown in Figs. 1 and 2, the inkjet recording device 1 includes an inkjet head 2, an IR heater 3, a platen heater 4, a heating heater 5, a cooling fan 6, a pre-heater 7, a ventilation fan 8, a carriage 9, a platen 11, a carriage moving mechanism 13, a motor 14 as a conveying means, and a control unit CONT. In the inkjet recording device 1, the control unit CONT shown in Fig. 2 controls the overall operation of the inkjet recording device 1.

[0184] The inkjet head 2 is a means for recording on the recording medium 10 by discharging and depositing ink from a nozzle (see FIG. 3). In this embodiment, the ink discharged from the nozzle of the inkjet head 2 is a collective term for the above-mentioned resin liquid composition and colored ink composition (hereinafter, also collectively referred to as "ink"). The inkjet head 2 may be either a line-type inkjet head (hereinafter, also referred to as "line head") or a serial-type inkjet head (hereinafter, also referred to as "serial head"). In the case of a line head, an image can be recorded on the recording medium by fixing the head and moving the recording medium 10 along the sub-scanning direction (T1-T2 direction in FIG. 2) and discharging ink droplets from the nozzle of the line head in conjunction with this movement. In the case of a serial head, an image can be recorded on the recording medium 10 by moving the serial head along the main scanning direction (S1-S2 direction in FIG. 2) and discharging ink droplets from the nozzle of the serial head in conjunction with this movement. This is called a main scan, or simply a scan, or a pass. In this embodiment shown in the figure, a serial head is used as the inkjet head 2. The inkjet head 2 is mounted on a carriage 9 shown in Fig. 2. The inkjet head 2 is scanned multiple times in the main scanning direction relative to the recording medium 10 by the operation of a carriage movement mechanism 13 that moves the carriage 9 in the main scanning direction of the recording medium 10.

[0185] Here, the main scanning direction (hereinafter also referred to as "MS") is the direction in which the carriage 9 carrying the inkjet head 2 moves. In FIG. 1, the conveyance of the recording medium 10 indicated by the arrow X It is a direction that intersects with the sub-scanning direction (hereinafter also referred to as "SS"), which is the feed direction. In FIG. 2, the width direction of the recording medium 10, that is, the direction S1-S2, is the main scanning direction, and the direction T1-T2 is the sub-scanning direction. Note that scanning is performed in either the main scanning direction, that is, the left or right direction of the inkjet recording device 1, in one scan. Recording is performed on the recording medium 10 by alternately repeating the main scan of the inkjet head 2 and the sub-scan, which is the transport of the recording medium 10. Note that the transport of the recording medium 10 in the sub-scanning direction is also referred to as the sub-scanning.

[0186] The ink ejection method in the inkjet head 2 can be a conventionally known method. For example, a method of ejecting ink by utilizing a change in the volume of an ink storage section caused by mechanical deformation of a piezoelectric element, or a method of ejecting ink by generating bubbles in the ink using an electrothermal conversion element such as a heating resistor, can be used. In this embodiment, a method of ejecting ink by mechanical deformation of a piezoelectric element is used. Details of the peripheral configuration of the inkjet head 2 and the carriage 9 will be described later.

[0187] The inkjet recording apparatus 1 includes an IR heater 3 and a platen heater 4 for primary heating, that is, for heating the recording medium 10 when the ink is ejected from the inkjet head 2. In this embodiment, at least one of the IR heater 3 and the platen heater 4 may be used to heat the recording medium 10 in the resin liquid composition application step and the ink-receiving composition application step.

[0188] By using the IR heater 3, the recording medium 10 can be heated from the inkjet head 2 side. As a result, the inkjet head 2 is also likely to be heated at the same time, but compared to heating the recording medium 10 from the back side thereof using a platen heater 4 or the like, the temperature can be increased without being affected by the thickness of the recording medium 10. Furthermore, by using the platen heater 4 when heating the recording medium 10, the recording medium 10 can be heated from the side opposite the inkjet head 2 side. As a result, the inkjet head 2 is relatively less likely to be heated. The surface temperature of the recording medium 10 when heated using the IR heater 3 or platen heater 4 is also referred to as the primary heating temperature.

[0189] The upper limit of the surface temperature of the recording medium 10 by the IR heater 3 or the platen heater 4 is preferably 50° C. or less, more preferably 45° C. or less, even more preferably 40° C. or less, and particularly preferably 38° C. or less. The lower limit of the surface temperature of the recording medium 10 is preferably 25° C. or more, more preferably 28° C. or more, even more preferably 30° C. or more, and particularly more preferably 32° C. or more. It is further preferably 35° C. or more, and more preferably 40° C. or more.

[0190] This reduces or eliminates the radiant heat received from the IR heater 3 and the platen heater 4, thereby suppressing drying and composition fluctuation of the ink in the inkjet head 2 and suppressing adhesion of the ink and resin to the inner wall of the inkjet head 2. Furthermore, the ink can be fixed early, improving image quality.

[0191] The heater 5 dries and solidifies the ink attached to the recording medium 10, that is, it is a heater for secondary heating. When the heater 5 heats the recording medium 10 on which an image has been recorded, the moisture contained in the ink evaporates and dissipates more quickly, and an ink film is formed by the resin contained in the ink. In this way, the ink film is firmly fixed or adhered on the recording medium 10, resulting in excellent film-forming properties, and a high-quality, highly abrasion-resistant image can be obtained in a short time. The upper limit of the surface temperature of the recording medium 10 by the heater 5 is preferably 120°C or less, more preferably 100°C or less, and even more preferably 90°C or less. The lower limit of the surface temperature of the recording medium 10 is 60°C or more. It is preferable that the temperature is 70° C. or higher, more preferably 70° C. or higher, and even more preferably 80° C. or higher. By keeping the temperature within the above range, a high-quality image can be obtained in a short time. The surface temperature of the recording medium 10 when heated by the heater 5 is also called the secondary heating temperature.

[0192] The inkjet recording apparatus 1 may have a cooling fan 6. After the ink recorded on the recording medium 10 is dried, the ink on the recording medium 10 is cooled by the cooling fan 6, whereby an ink coating film with good adhesion can be formed on the recording medium 10.

[0193] The inkjet recording apparatus 1 may also include a preheater 7 that preheats the recording medium 10 before the ink is applied to the recording medium 10. Furthermore, the inkjet recording apparatus 1 may also include a ventilation fan 8 so that the ink applied to the recording medium 10 can be dried more efficiently.

[0194] Below the carriage 9, there are provided a platen 11 on which the recording medium 10 is transported, a carriage movement mechanism 13 that moves the carriage 9 relatively to the recording medium 10, rollers that transport the recording medium 10 in the sub-scanning direction, and a motor 14 as a transport means that drives the rollers. The operations of the carriage movement mechanism 13 and the motor 14 are controlled by a control unit CONT.

[0195] In this embodiment, the inkjet head 2 ejects and deposits ink onto the recording medium 10 while moving in accordance with the movement of the carriage 9. In this manner, in this embodiment, the inkjet head 2 performs recording by scanning multiple times in the main scanning direction relative to the recording medium 10.

[0196] In this embodiment, the cartridge 12 that supplies ink to the inkjet head 2 is made up of a plurality of independent cartridges. The cartridge 12 is detachably mounted on a carriage 9 on which the inkjet head 2 is mounted. Each of the plurality of cartridges 12 is filled with a different type of ink, and ink is supplied from the cartridge 12 to each nozzle. Note that, although this embodiment shows an example in which the cartridge 12 is mounted on the carriage 9, the present invention is not limited to this, and the cartridge 12 may be provided at a location other than the carriage 9 and ink may be supplied to each nozzle by a supply pipe (not shown).

[0197] Fig. 3 is a schematic plan view showing an example of the arrangement of nozzle groups on a nozzle surface of an inkjet head. As shown in Fig. 3, the inkjet head 2 has a nozzle surface 2a including a plurality of nozzles for ejecting ink. In the example shown in Fig. 3, the nozzle surface 2a of the inkjet head 2 has a plurality of colored ink nozzle groups 15a, 15b, 15c, and 15d in which nozzles for ejecting colored ink compositions are arranged in the sub-scanning direction (SS direction in Fig. 3), and a resin liquid nozzle group 16 for ejecting a resin liquid composition. In Fig. 3, the plurality of colored ink nozzle groups 15a, 15b, 15c, and 15d and the resin liquid nozzle group 16 are each composed of two nozzle rows shifted by a half pitch in the sub-scanning direction, but are not limited thereto. There is no problem if only some of the color ink nozzle groups 15a, 15b, 15c, and 15d are used, and a configuration may be adopted in which white ink or non-white ink (for example, color ink compositions such as black ink, cyan ink, magenta ink, and yellow ink) is ejected from some of the color ink nozzle groups 15a, 15b, 15c, and 15d. There may be a plurality of resin liquid nozzle groups 16. In the example shown in FIG. 3, there is one resin liquid nozzle group 16. The color ink nozzle groups 15a, 15b, 15c, and 15d and the resin liquid nozzle group 16 are arranged in parallel at intervals in the main scanning direction (MS direction in FIG. 3).

[0198] Furthermore, in the present embodiment, in the example of the arrangement of the nozzle groups shown in FIG. In the example shown, the resin liquid nozzle group 16 is at the left end in the main scanning direction in the figure, but the resin liquid nozzle group 16 may be arranged at the right end opposite the left end in the main scanning direction. Also, the resin liquid nozzle group 16 may be arranged at the left end and the right end in the main scanning direction in Fig. 3. Also, the resin liquid nozzle group 16 may be arranged between the color ink nozzle groups 15a, 15b, 15c, and 15d in Fig. 3.

[0199] 2.2. Inkjet recording method Either a line head or a serial head may be used as the inkjet head. The recording method according to this embodiment is a serial type recording method using the inkjet recording device 1 equipped with the above-mentioned inkjet head 2, and recording is performed by alternately repeating main scanning, in which the inkjet head 2 moves relatively in the main scanning direction of the recording medium 10 while ejecting ink to adhere to the recording medium 10, and sub-scanning, in which the recording medium 10 is transported (see FIG. 2).

[0200] In the case of a serial printing method, the number of main scans in which a nozzle group of a specific ink used for printing passes opposite to the printing position on the printing medium 10 is called the number of main scans of the ink. The number of main scans is determined for each nozzle group. For example, when one nozzle group in FIG. 3 is filled with ink and used for printing, if the distance of one sub-scan is half the length of the nozzle group in the sub-scan direction, the number of main scans of the ink is two. The number of main scans can be increased by shortening the distance of one sub-scan, and can be decreased by lengthening the distance. A larger number of main scans is preferable in that the total amount of ink to be applied can be increased and that the ink can be applied in parts by multiple main scans. On the other hand, a smaller number of main scans is preferable in that the printing speed is high. The number of main scans is also called the number of passes.

[0201] In this embodiment, the maximum distance of one main scan is preferably 50 cm or more. The "maximum distance of one main scan" refers to the distance that one point of the inkjet head 2 faces the recording medium 10 when recording is performed from one end to the other in the main scanning direction of the recording medium 10 in one main scan. The distance is preferably 50 to 500 cm, more preferably 50 to 400 cm, even more preferably 55 to 300 cm, and even more preferably 60 to 200 cm. Also, it is particularly preferably 70 to 190 cm, more particularly preferably 100 to 180 cm, and even more particularly preferably 130 to 170 cm. By having the distance of 50 cm or more, a recorded product that is useful for display purposes and the like can be obtained. The upper limit of the distance is not particularly limited, but is preferably 500 cm or less from the viewpoint of the configuration of the inkjet recording device 1. When recording, scanning that is shorter than the maximum distance of one main scan may be performed depending on the image to be recorded.

[0202] It is more preferable to use a recording medium 10 in which the width of the main scanning of the recording medium 10 is within the above-mentioned maximum distance range. In this case, it is preferable in that the maximum distance of one main scanning pass can be set to the above-mentioned range.

[0203] 2.3. Resin liquid composition adhesion process The resin liquid composition application step is a step of applying the resin liquid composition constituting the ink set according to one embodiment of the present invention to a recording medium. The method of applying the resin liquid composition is not particularly limited, but in this embodiment, from the viewpoint of miniaturization of the inkjet recording device 1, it is preferable to eject the resin liquid composition from the inkjet head 2 using an inkjet method.

[0204] In the recording method according to the present embodiment, a resin liquid composition application step is provided in addition to the color ink composition application step described later. This allows the resin liquid composition to be applied directly to the recording medium to form a base layer (undercoat), or the color ink composition layer applied to the recording medium can be formed by applying the resin liquid composition directly to the recording medium. Furthermore, the resin liquid composition can be applied from above to form an overcoat. In this way, the resin liquid composition can be concentrated at the interface of the colored ink composition layer, reducing the pigment present at the interface and tending to prevent a decrease in laminate peel strength and blocking resistance. Even when the resin liquid composition is used as an undercoat, the resin liquid composition migrates to the air-layer interface of the colored ink composition layer. Even when the resin liquid composition is used as an overcoat, the resin liquid composition migrates to the interface of the colored ink composition layer with the recording medium. The amount of adhesion of the resin liquid composition can be controlled independently of the amount of adhesion of the colored ink composition, making it easy to adjust the amounts of adhesion of both.

[0205] The recording medium is not particularly limited, but is preferably a low-absorption recording medium or a non-absorption recording medium, and is particularly preferably a non-absorption recording medium. The recording medium is the same as that described in the ink set above, and therefore the description thereof will be omitted.

[0206] In this embodiment, the resin liquid composition application step may be performed before or after the colored ink composition application step described later, or may be performed simultaneously. In the arrangement of the nozzle group shown in FIG. 3, the resin liquid composition is applied using all the nozzles of the resin liquid nozzle group, and the colored ink composition is applied using only the nozzles on the downstream side in the sub-scanning direction of the colored ink nozzle group, so that the resin liquid composition can be applied before or simultaneously with the colored ink composition. In addition, for example, the resin liquid composition is applied using only the nozzles on the upstream side in the sub-scanning direction of the resin liquid nozzle group, and the colored ink composition is applied using only the nozzles on the downstream side in the sub-scanning direction of the colored ink nozzle group, so that the resin liquid composition can be applied before the colored ink composition.

[0207] In the recording method according to the present embodiment, it is more preferable that the resin liquid composition application step is performed before the colored ink composition application step. By adopting such an order, the resin liquid composition can be applied directly to the recording medium. In this case, the resin liquid composition tends to be concentrated at the interface of the colored ink composition layer, particularly with the recording medium, and the pigment present at the interface can be further reduced, and the decrease in laminate peel strength and blocking resistance can be more effectively prevented. In addition, the urethane resin contained in the resin liquid composition has an alicyclic structure or an aromatic ring structure, and tends to improve wettability to a recording medium made of a polyolefin-based non-polar material. Therefore, if the resin liquid composition application step is performed before the colored ink composition application step, the resin liquid composition can be uniformly applied even when a polyolefin-based non-polar material is used for the recording medium. As a result, the resin liquid composition tends to be concentrated at the interface of the colored ink composition layer, particularly with the recording medium, and the pigment present at the interface can be further reduced, and the decrease in laminate peel strength and blocking resistance can be more effectively prevented.

[0208] It is preferable that the recording medium 10 is heated by a preheater 7 shown in FIG. 1 before the resin liquid composition application step, or by an IR heater 3 or a platen heater 4 shown in FIG. 1 during the resin liquid composition application step. By applying the resin liquid composition onto the heated recording medium 10, the resin liquid composition discharged onto the recording medium 10 is easily spread on the recording medium 10 or on the colored ink composition applied in the colored ink composition application step described below, and the resin liquid composition can be applied uniformly. In this way, the pigment present at the interface of the colored ink composition layer can be reduced, and a decrease in laminate peel strength and blocking resistance can be more effectively prevented.

[0209] Here, the surface temperature of the recording medium 10 when the resin liquid composition is applied can be set independently of the preferred range of surface temperatures of the recording medium 10 when the colored ink composition is applied, which will be described later. For example, the surface temperature of the recording medium 10 when the resin liquid composition is applied is preferably 50° C. or lower, more preferably 45° C. or lower, and even more preferably 38° C. or lower. In addition, the surface temperature of the recording medium 10 when the resin liquid composition is applied can be set independently of the preferred range of surface temperatures of the recording medium 10 when the colored ink composition is applied. The lower limit of the temperature is preferably 25° C. or higher, more preferably 28° C. or higher. It is further preferably 30° C. or higher, more preferably 35° C. or higher, and even more preferably 40° C. or higher. When the surface temperature of the recording medium 10 when the resin liquid composition is applied is within the above range, the resin liquid composition can be applied uniformly to the recording medium 10, and the abrasion resistance and image quality can be improved. In addition, the effect of heat on the inkjet head 2 can be suppressed.

[0210] 2.4. Colored ink composition application step The color ink composition application step is a step of applying the color ink composition constituting the ink set according to one embodiment of the present invention described above to a recording medium by an inkjet method.

[0211] In this embodiment, the color ink composition applying step may be performed prior to or after the resin liquid composition applying step described above, or may be performed simultaneously with the resin liquid composition applying step.

[0212] In addition, in the recording method according to the present embodiment, it is preferable to apply the color ink composition and the resin liquid composition to the recording medium in an overlapping manner. By applying them in an overlapping manner in this manner, the resin liquid composition can be concentrated at the interface of the color ink composition layer, and the pigment present at the interface can be reduced, which may further prevent the deterioration of the laminate peel strength and blocking resistance.

[0213] When the color ink composition is applied to the recording medium so as to overlap a part or all of the area to which the resin liquid composition is applied, the color ink composition may be applied so as to overlap at least a part of the area to which the resin liquid composition is applied. Specifically, the color ink composition is preferably applied so as to overlap 50% or more of the area to which the resin liquid composition is applied, more preferably so as to overlap 60% or more, and even more preferably so as to overlap 70% or more.

[0214] In addition, when the resin liquid composition is applied to the recording medium so as to overlap a part or all of the area to which the colored ink composition is applied, the resin liquid composition may be applied so as to overlap at least a part of the area to which the colored ink composition is applied. Specifically, the resin liquid composition is preferably applied so as to overlap 50% or more of the area to which the colored ink composition is applied, more preferably so as to overlap 60% or more, and even more preferably so as to overlap 70% or more.

[0215] In this specification, the term "region" refers to a portion occupying a certain area on a recording medium where the amount of ink applied to the region is approximately constant. A region is a region that can be visually recognized as having the same color, for example, 1 mm 2 Furthermore, the amount of adhesion is approximately constant means that, for example, when the duty is low, the amount of ink adhesion differs strictly between positions where ink dots land and positions where ink dots do not land, but the area is a macroscopic (macro) range larger than the area of ​​one dot, and macroscopically the amount of ink adhesion is constant within the area, and unevenness in the amount of adhesion due to the presence or absence of adhesion of ink dots is ignored.

[0216] In addition, when the duty is low, even in a region where both the resin liquid composition and the colored ink composition are attached, there may be a portion where the resin liquid dot and the colored ink dot do not overlap microscopically (for example, on the scale of a droplet (landed dot) in an inkjet method), but it is assumed that the ink is laminated macroscopically, and the presence of a portion where the dots do not overlap when viewed on a dot-by-dot basis is ignored. Therefore, the attached region here is considered to be the region where the resin liquid composition and the colored ink composition are laminated as the entire region.

[0217] In this specification, the term "Duty" refers to a value calculated by the following formula (1). Duty(%)={actual print dot count / (vertical resolution x horizontal resolution)} x 100 …(1) (In the formula, "actual print dot number" is the number of actual print dots per unit area, and "vertical resolution" and "horizontal resolution" are the resolutions per unit area, respectively.)

[0218] Furthermore, in the recording method according to the present embodiment, in the color ink composition application step, a non-white ink containing a non-white pigment and a white ink containing a white pigment may be used as the color ink composition, and the non-white ink and the white ink may be applied in a layered manner. Note that "adhering in a layered manner" has the same meaning as above. According to the recording method according to the present embodiment, even in such a form, it is possible to achieve both excellent nozzle clogging recovery and excellent laminate peel strength and blocking resistance of the recorded matter.

[0219] Examples of such a form in which non-white ink and white ink are deposited in an overlapping manner include depositing white ink followed by depositing non-white ink, and depositing white ink followed by depositing non-white ink.

[0220] Among these, it is particularly preferable to apply the white ink after applying the non-white ink, from the viewpoint of obtaining the effects of the present invention more effectively. This type of recording method is called reverse printing, and generally, recording is performed on a transparent medium, and the recorded matter is used by viewing it from the reverse side of the recorded surface.

[0221] The color ink composition applying step may include a heating step (hereinafter also referred to as a "primary heating step") of heating the recording medium 10 with an IR heater 3 or a platen heater 4 before or simultaneously with the color ink composition applying step, and is preferably performed on the recording medium 10 that has been heated in the primary heating step. The primary heating step allows the color ink composition to be quickly dried on the recording medium 10, suppresses bleeding, and allows the formation of an image with excellent image quality.

[0222] The upper limit of the surface temperature of the recording medium 10 when the colored ink composition is attached to the recording medium 10 by the primary heating step is preferably 50° C. or less, more preferably 45° C. or less, and even more preferably 40° C. or less. When the surface temperature of the recording medium when the colored ink composition is attached is within the above range, the influence of heat on the inkjet head 2 can be suppressed, and clogging of the inkjet head 2 and the nozzles can be prevented. In addition, the lower limit of the surface temperature of the recording medium 10 during inkjet recording is preferably a temperature higher than room temperature, preferably 28° C. or more, more preferably 30° C. or more, and even more preferably 32° C. or more. When the surface temperature of the recording medium when the colored ink composition is attached is within the above range, the colored ink composition on the recording medium 10 can be quickly dried and fixed early, bleeding can be suppressed, and an image with excellent image quality can be formed.

[0223] 2.5.Drying process The recording method according to the present embodiment may include a step of drying the applied ink after the color ink composition application step or the resin liquid composition application step. Drying may be performed at room temperature, or may be performed by heating the recording medium 10 to which the ink is applied. The heating step is hereinafter also referred to as a "secondary heating step", and may be, for example, a drying step in which the recording medium 10 to which the ink is applied is heated by a heater 5 shown in FIG. 1.

[0224] Heating can be performed by, for example, a radiation method such as an IR heater that radiates radiation that generates heat toward the recording medium 10, a transmission method that conducts heat from a member in contact with the recording medium 10 to the recording medium 10, or a blowing method that blows hot air onto the recording medium 10. This causes the resin contained in the ink on the recording medium 10 to melt and form an ink film, which is firmly fixed on the recording medium 10 and has excellent film-forming properties, making it possible to obtain a high-quality image with excellent abrasion resistance in a short period of time, which is preferable.

[0225] The upper limit of the surface temperature of the recording medium 10 due to drying is preferably 120° C. or less, more preferably 110° C. or less, and even more preferably 100° C. or less. The lower limit of the surface temperature of the recording medium 10 is preferably 60° C. or more, more preferably 70° C. or more, and even more preferably 80° C. or more. By keeping the temperature within the above range, clogging recovery is ensured, and a high-quality image with excellent abrasion resistance can be obtained in a short period of time.

[0226] After the drying step, a step of cooling the ink on the recording medium 10 by the cooling fan 6 shown in FIG. 1 may be included.

[0227] 2.6.Other processes

[0228] The recording method according to this embodiment may include a cleaning step in which ink is discharged by means other than a pressure generating means for ejecting ink for recording, that is, by a mechanism other than the mechanism for ejecting ink for recording provided in the inkjet head 2.

[0229] The mechanism for ejecting ink for recording provided in the inkjet head 2 includes a piezoelectric element or a heater element provided in a pressure chamber (not shown) for applying pressure to the ink. This cleaning step may be a step of applying pressure from the outside to the inkjet head 2 to eject the ink from the nozzles. By providing this step, even if there is a concern that the resin may be melted onto the inner wall of the inkjet head 2, this can be suppressed, and ejection stability can be further improved.

[0230] Other mechanisms in the above cleaning process include applying negative pressure and applying positive pressure from the upstream of the inkjet head 2. These are not flushing, that is, ink discharge by the function of the inkjet head 2 itself. In other words, they are not discharged by using a function to eject ink from the inkjet head 2 during recording.

[0231] 3. Working Example The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. In the following, "%" is based on mass unless otherwise specified.

[0232] 3.1.Synthesis of urethane resin Each urethane resin emulsion was prepared as follows.

[0233] <Preparation of Urethane Resin Emulsion A1> In a reaction vessel equipped with a stirrer, reflux condenser and thermometer, 220g of polytetramethylene glycol (PTMG2000 manufactured by Mitsubishi Chemical: number average molecular weight 2000), 140g of 2,2-dimethylolpropionic acid (DMPA) and 130g of methyl ethyl ketone (MEK: bp 79.6°C) were charged under a nitrogen stream and heated to 65°C to dissolve the DMPA. 330g of 4,4'-dicyclohexylmethane diisocyanate (MCHDI) and 0.26g of urethane catalyst XK-614 (manufactured by Kusumoto Chemicals) were added and heated to 75°C. The urethane reaction was carried out over 5 hours to obtain an isocyanate-terminated urethane prepolymer.

[0234] The reaction mixture was then cooled to 70°C, and 40 g of triethanolamine was added to it. From the mixture, 800 g was taken out and added to a mixed solution of 540 g of water and 40 g of triethanolamine under strong stirring. Then, 160 g of ice was added, and 28 g of a 35 wt% aqueous solution of bicycloheptane dimethanamine (BCHDMA) was added to carry out a chain extension reaction, resulting in a solid. Methyl ethyl ketone and a portion of the water were distilled off so that the liquid concentration became 30%, to obtain a urethane resin emulsion A1 (urethane resin component 30%, water 70%, acid value 80 mgKOH / g).

[0235] <Preparation of Urethane Resin Emulsion A2> In producing urethane resin emulsion A1, 280 g of isophorone diisocyanate (IPDI) was used instead of 330 g of 4,4'-dicyclohexylmethane diisocyanate (MCHDI), the amount of polytetramethylene glycol (PTMG2000 manufactured by Mitsubishi Chemical: number average molecular weight 2000) was 260 g, and the amount of 2,2-dimethylolpropionic acid (DMPA) was 138 g. In the same manner, urethane resin emulsion A2 (urethane resin component 30%, water 70%, acid value 80 mgKOH / g) was obtained.

[0236] <Preparation of urethane resin emulsion A3> In the production of urethane resin emulsion A1, 235 g of 1,3-bis(isocyanatomethyl)cyclohexane (BIMCH) was used instead of 330 g of 4,4'-dicyclohexylmethane diisocyanate, and the amounts of PTMG2000 and DMPA were changed to 275 g and 130 g, respectively, to obtain urethane resin emulsion A3 (urethane resin component 30%, water 70%, acid value 80 mgKOH / g).

[0237] <Preparation of Urethane Resin Emulsion A4> In producing urethane resin emulsion A2, 300g of m-bis(isocyanatepropyl)benzene (BICPB) was used instead of 280g of isophorone diisocyanate (IPDI), 200g of polytetramethylene glycol (PTMG2000 manufactured by Mitsubishi Chemical: number average molecular weight 2000), 130g of 2,2-dimethylolpropionic acid (DMPA), and 55g of aqueous bicycloheptane dimethanamine (BCHDMA) solution were used, and the same procedure was used to obtain urethane resin emulsion A4 (urethane resin component 30%, water 70%, acid value 80mgKOH / g).

[0238] <Preparation of Urethane Resin Emulsion A5> In producing urethane resin emulsion A1, 208 g of m-bis(isocyanate methyl)benzene (BICMB) was used instead of 280 g of 4,4'-dicyclohexylmethane diisocyanate (MCHDI), the amount of polytetramethylene glycol (PTMG2000 manufactured by Mitsubishi Chemical: number average molecular weight 2000) was 157 g, and the amount of 2,2-dimethylolpropionic acid (DMPA) was 125 g. In the same manner, urethane resin emulsion A5 (urethane resin component 30%, water 70%, acid value 80 mgKOH / g) was obtained.

[0239] <Preparation of Urethane Resin Emulsion A6> In producing urethane resin emulsion A2, 194 g of polytetramethylene glycol (PTMG3000, manufactured by Mitsubishi Chemical; number average molecular weight 3000) and 16 g of polytetramethylene glycol (PTMG250, manufactured by Mitsubishi Chemical; number average molecular weight 250) were added instead of 260 g of polytetramethylene glycol (PTMG2000, manufactured by Mitsubishi Chemical; number average molecular weight 2000), and the average molecular weight of polytetramethylene glycol was set to 450. A polyether-based urethane resin emulsion A6 (urethane resin component 30%, water 70%, acid value 80 mgKOH / g) was obtained in the same manner.

[0240] <Preparation of Urethane Resin Emulsion A7> In the preparation of urethane resin emulsion A2, 520 g of polytetramethylene glycol (PTMG4000 manufactured by Mitsubishi Chemical: number average molecular weight 4000) was used instead of 260 g of polytetramethylene glycol (PTMG2000 manufactured by Mitsubishi Chemical: number average molecular weight 2000) and 117 g of 2,2-dimethylolpropionic acid (DMPA) was used. An ether-based urethane resin emulsion A7 (urethane resin component 30%, water 70%, acid value 55 mgKOH / g) was obtained.

[0241] <Preparation of Urethane Resin Emulsion A8> In producing the urethane resin emulsion A2, 260 g of polytetramethylene glycol (PTMG2000 manufactured by Mitsubishi Chemical: number average molecular weight 2000) was replaced with 253 g of polyoxypropylene glycol (PPG2000: number average molecular weight 2000) and 1 g of trimethylolpropane (TMP) was added, and the same procedure was repeated to obtain a polyether-based urethane resin emulsion A8 (urethane resin component 30%, water 70%, acid value 80 mgKOH / g).

[0242] <Preparation of Urethane Resin Emulsion A9> A urethane resin emulsion A9 (urethane resin component 30%, water 70%, acid value 89 mgKOH / g) was obtained in the same manner as in the production of the urethane resin emulsion A2, except that 210 g of 1,6-hexamethylene diisocyanate (1,6-HDDI) was used instead of 280 g of isophorone diisocyanate (IPDI).

[0243] <Preparation of Urethane Resin Emulsion A10> In producing urethane resin emulsion A2, the same procedure was repeated except that the amount of 2,2-dimethylolpropionic acid (DMPA) was reduced from 138 g to 115 g, the amount of isophorone diisocyanate (IPDI) was reduced from 280 g to 210 g, the amount of polytetramethylene glycol (PTMG2000 manufactured by Mitsubishi Chemical: number average molecular weight 2000) was reduced from 260 g to 125 g, and the amount of 35 wt % aqueous bicycloheptane dimethanamine (BCHDMA) solution was reduced to 7 g, to obtain urethane resin emulsion A10 (urethane resin component 30%, water 70%, acid value 102 mgKOH / g).

[0244] <Preparation of Urethane Resin Emulsion A11> In the production of urethane resin emulsion A2, the amount of 2,2-dimethylolpropionic acid (DMPA) was reduced from 138 g to 40 g, the amount of isophorone diisocyanate (IPDI) was reduced from 280 g to 100 g, and the amount of bicycloheptane dimethanamine (BCHDMA) aqueous solution was reduced from 7 g, and a urethane resin emulsion A11 (urethane resin component 30%, water 70%, acid value 49 mgKOH / g) was obtained in the same manner.

[0245] The above urethane resin emulsions A1 to A11 are summarized in the following Table 1. The unit of the added amount shown in the following Table 1 is g.

[0246] [Table 1]

[0247] 3.2. Preparation of resin liquid composition and colored ink composition Each component shown in Table 2 below was mixed and thoroughly stirred, and then filtered under reduced pressure using a microfilter (Millipore) with a pore size of 5.0 μm to prepare each resin liquid composition. Each component was mixed and stirred so as to obtain the blending ratio shown in Table 3 below, filtered using a membrane filter with a pore size of 10 μm, and degassed using a vacuum pump to obtain each colored ink composition. The composition of each resin liquid composition and each colored ink composition is shown in Table 2 below.

[0248] In Table 2, the contents of the resin liquid composition and the colored ink composition are in mass%, and the contents of the pigment and the urethane resin emulsion are expressed as solid content equivalents. The remaining amount of ion-exchanged water indicates that the amount added is such that the total mass of the composition becomes 100% by mass.

[0249] For the pigments (PB15:3 and PW6) used in the preparation of the colored ink compositions, pigment dispersions were prepared in advance as described below, and these were used in the preparation of the colored ink compositions.

[0250] <Preparation of white pigment dispersion> First, 4 parts by mass of acrylic acid-acrylic acid ester copolymer (weight average molecular weight: 25,000, acid value: 18) was added as a resin dispersant to 155 parts by mass of ion-exchanged water in which 0.1 parts by mass of 30% aqueous ammonia solution (neutralizer) was dissolved, and dissolved. 40 parts by mass of titanium dioxide (CI Pigment White 6) as a white pigment was added thereto, and dispersion treatment was performed for 10 hours in a ball mill using zirconia beads. Then, centrifugal filtration was performed using a centrifuge to remove impurities such as coarse particles and dust, and the concentration of the white pigment was adjusted to 20% by mass, thereby obtaining a white pigment dispersion. The particle diameter of the white pigment was 350 nm in average particle diameter.

[0251] <Preparation of non-white pigment dispersion> First, 7.5 parts by mass of acrylic acid-acrylic acid ester copolymer (weight average molecular weight: 25,000, acid value: 180) was added as a resin dispersant to 160.5 parts by mass of ion-exchanged water in which 2 parts by mass of 30% aqueous ammonia solution (neutralizer) was dissolved, and dissolved. 30 parts by mass of CI Pigment Blue 15:3 was added as a cyan pigment, and dispersion treatment was performed for 10 hours using a ball mill with zirconia beads. Then, centrifugal filtration was performed using a centrifuge to remove impurities such as coarse particles and dust, and the cyan pigment concentration was adjusted to 15% by mass, to obtain a non-white pigment (cyan pigment) dispersion. The particle diameter of the cyan pigment at that time was 100 nm in average particle diameter.

[0252] [Table 2]

[0253] Details of the components in Table 2 above are as follows: <Pigments> PB15:3 (CI Pigment Blue 15:3, non-white pigment) · PW6 (CI Pigment White 6, white pigment) <Other> Acrylic resin (styrene-acrylic resin, product name "Joncryl 62J", manufactured by BASF Japan Ltd.) 1,2-HD (1,2-Hexanediol) ·PG (Propylene Glycol) 2P (2-pyrrolidone, nitrogen-containing solvent) SAG503A (product name "Silface SAG503A", product name of Nissin Chemical Industry Co., Ltd., silicone-based surfactant) · TiPA (triisopropanolamine, pH adjuster) ·EDTA (ethylenediaminetetraacetic acid disodium salt, a chelating agent)

[0254] 3.3. Preparation of Recorded Materials for Evaluation Each of the colored ink compositions and resin liquid compositions obtained above was filled in an ink cartridge, and the ink cartridge was installed in an inkjet printer. As the inkjet printer, a modified inkjet printer (product name "PX-G930") manufactured by Seiko Epson Corporation was used (modified "PX-G930"). A heater was attached to the platen section to make it possible to heat the recording medium during printing. The order in which the colored ink compositions and resin liquid compositions were printed on the recording medium and the inks used were as described in Tables 3 to 5 below, and the recording medium surface temperature in the platen area was set to 45°C. Printing was performed with a dot density of 1440 dpi x 1440 dpi so that the recording duty was 100%. Note that "recording duty is 100%" refers to the recording duty of a solid image recorded under the condition that one ink droplet with a mass of 14 ng ± 10% per droplet is applied to a unit area of ​​1 / 1440 inch x 1 / 1440 inch. A corona-treated PET film (manufactured by Futamura Chemical, product name "FE-2001", 50 μm thick) was used as the recording medium. The environment around the printer during printing was a temperature of 23°C and a relative humidity of 55%. After the ink and other materials were attached, the recording medium was heated and dried in an oven at a recording medium surface temperature of 75°C for 3 minutes to obtain a recorded matter.

[0255] In Tables 3 to 5, "resin liquid (undercoat)" refers to conditions for printing a resin liquid composition on a recording medium before ink is applied. In Tables 3 to 5, "first layer ink" refers to an ink that is applied first, and when a resin liquid composition is applied in "resin liquid (undercoat)", refers to conditions for applying a colored ink composition over the resin liquid composition and printing. In Tables 3 to 5, "second layer ink" refers to an ink that is applied second, and refers to conditions for applying a second colored ink composition over the colored ink composition applied in "first layer ink" and printing. In Tables 3 to 5, "resin liquid (overcoat)" refers to conditions for applying a resin liquid composition over the colored ink composition applied in "first layer ink" or "second layer ink" and printing.

[0256] [Table 3]

[0257] [Table 4]

[0258] [Table 5]

[0259] 3.4. Evaluation method 3.4.1.Laminate peel strength test Toyo Morton's aliphatic ester-based TM-569 (base agent) and CAT-10L (hardener) were applied at a coating weight of 2.5 g (non-volatile content) / m2 using a test laminator (Musashino Machinery Co., Ltd.). 2 The diluted solution was applied to each of the recorded materials obtained above so as to become as follows: and the diluted solution was dried by evaporating the dilution solvent with a dryer.

[0260] The adhesive surface of each recording material coated with the adhesive composition was laminated with a sealant film (PE film, manufactured by Mitsui Tocello, product name "TUX-HCE", 60 μm thick). The adhesive composition was then cured by aging the laminated film at 40° C. for 3 days to obtain a laminated film sheet.

[0261] A sample of each laminated film was cut to a width of 15 mm and subjected to a peel strength test using a tensile tester "TENSILON RTG1250" manufactured by A&D Co., Ltd. A 50N load cell was used and the test was performed at a speed of 5 mm / s. The sample was folded 180°, peeled 25 mm from the test plate, and fixed to a chuck. The first 25 mm after the measurement was ignored, and the measurement value was measured over a length of 50 mm from that point onward three times. The average value was used to determine the laminate peel strength according to the following evaluation criteria. (Evaluation Criteria) A: The average value of three measurements was 3N / 15mm or more. B: The average value of three measurements was greater than 1N / 15mm and less than 3N / 15mm. C: The average value of three measurements was 0.5N / 15mm or more and less than 1N / 15mm. D: The average value of the measurements was less than 0.5N / 15mm.

[0262] 3.4.2. Clogging recovery test The inkjet printer was filled with the colored ink composition and the resin liquid composition, and it was confirmed that the composition was discharged from all the nozzles in the nozzle row. The printer was then left for 2 days under an environment of 40°C temperature and 20% relative humidity. After the printer was left standing, the colored ink composition and the resin liquid composition were discharged from all the nozzles, and cleaning was repeatedly performed, and the number of cleanings was measured. Based on the number of cleanings, the clogging recovery was evaluated according to the following evaluation criteria. (Evaluation Criteria) A: Ink was ejected from all nozzles after one or two cleanings. B: Ink was ejected from all nozzles after three or four cleanings. C: There were nozzles that did not eject even after four cleanings.

[0263] 3.4.3. Blocking resistance evaluation test A sample was prepared by overlapping the printed surface of the recorded material obtained in "3.3. Preparation of Recorded Material for Evaluation" above with the non-printed surface of the recorded material (non-corona treated). The sample was used to measure 5 kgf / cm2 using a "Blocking Tester CO-201" manufactured by Tester Sangyo Co., Ltd. 2 (50 mmφ) and left at 50° C. for 24 hours. After leaving the film, the overlapped films were peeled off and the blocking resistance was evaluated according to the following criteria. (Evaluation Criteria) A: No transcription at all. B: Faintly transferred. C: Clearly transcribed.

[0264] 3.5.Evaluation Results The results of the evaluation tests are shown in Tables 2 to 5 above.

[0265] From the above evaluation results, each of the Examples was excellent in laminate peel strength and blocking resistance, whereas each of the Comparative Examples was inferior in either laminate peel strength or blocking resistance.

[0266] More specifically, from Examples 1 and 15, when the colored ink composition was a white ink, the laminate peel strength was slightly decreased, and when the colored ink composition was a non-white ink, the blocking resistance was slightly decreased.

[0267] From Examples 1 and 10, when a nitrogen-containing solvent was contained in the resin liquid composition, the laminate peel strength was improved, but the clogging recovery property was slightly decreased.

[0268] From Examples 1 and 11, even when a white ink was used, if the ink composition directly overlapping the resin liquid composition was a non-white ink, the laminate peel strength was improved.

[0269] From Examples 11 and 12, it was found that when the resin liquid composition was not directly applied to the recording medium, the laminate peel strength decreased.

[0270] From Examples 12 and 13, it can be seen that when the urethane resin emulsion A1 was contained in the non-white ink, the laminate peel strength was improved.

[0271] From Examples 4 and 14, it was found that when the white ink contained an acrylic resin, the blocking resistance improved, but the laminate peel strength decreased.

[0272] In Example 19, the lamination strength and blocking resistance were excellent. When the urethane resin emulsion A1 was contained in the white ink, the clogging recovery performance was reduced.

[0273] In contrast, in Comparative Examples 1 and 2, since no resin liquid composition containing a urethane resin having an alicyclic structure or aromatic structure was used, the laminate peel strength and blocking resistance were poor.

[0274] In Comparative Examples 3 to 8, the acid value of the urethane resin contained in the liquid resin composition was outside the prescribed range, and therefore the laminate peel strength and blocking resistance were poor.

[0275] From Comparative Example 9, it was found that even if the resin liquid composition was not used and the urethane resin emulsion A1 was contained in the colored ink composition, the effect of improving the laminate peel strength and blocking resistance could not be obtained.

[0276] The following can be derived from the above-described embodiment.

[0277] One embodiment of the ink set is An ink set comprising a colored ink composition which is a water-based inkjet ink containing a pigment, and a water-based resin liquid composition which contains a resin, The resin liquid composition contains a urethane resin having an alicyclic structure or an aromatic ring structure and an acid value of 50 to 100 mgKOH / g.

[0278] In the above ink set embodiment, The urethane resin may contain at least one component selected from dicyclohexylmethane diisocyanate, isophorone diisocyanate, 1,3-bis(isocyanatemethyl)cyclohexane, m-bis(isocyanatepropyl)benzene, and m-bis(isocyanatemethyl)benzene.

[0279] In the above ink set embodiment, The color ink composition may include a white ink containing a white pigment and a non-white ink containing a non-white pigment.

[0280] In the above ink set embodiment, The colored ink composition may be a white ink containing a white pigment.

[0281] In the above ink set embodiment, The white pigment content of the white ink may be 5 to 20% by mass.

[0282] In the above ink set embodiment, The urethane resin may contain polytetramethylene glycol as a constituent component.

[0283] In the above ink set embodiment, The polytetramethylene glycol may have a number average molecular weight of 500 to 3,000.

[0284] In the above ink set embodiment, The colored ink composition may contain a resin other than the urethane resin.

[0285] In the above ink set embodiment, The colored ink composition may contain an acrylic resin.

[0286] In the above ink set embodiment, The content of the urethane resin in the liquid resin composition may be 1 to 15% by mass.

[0287] In the above ink set embodiment, The urethane resin may be resin particles.

[0288] In the above ink set embodiment, The resin liquid composition may contain no more than 10% by mass of a nitrogen-containing solvent.

[0289] In the above ink set embodiment, It may be used for recording on low absorption or non-absorption recording media.

[0290] In the above ink set embodiment, The recorded matter recorded using the ink set of the above embodiment may be used after a sealant film treatment is applied to the recorded surface.

[0291] One aspect of the recording method is a color ink composition applying step of applying the color ink composition to a recording medium by an ink jet method; and a resin liquid composition applying step of applying the resin liquid composition to the recording medium.

[0292] In the above recording method, The colored ink composition and the resin liquid composition may be applied to the recording medium in an overlapping manner.

[0293] In the above recording method, The resin liquid composition applying step may be performed prior to the colored ink composition applying step.

[0294] In the above recording method, In the color ink composition applying step, a non-white ink containing a non-white pigment and a white ink containing a white pigment may be used as the color ink composition, and the non-white ink and the white ink may be applied in an overlapping manner.

[0295] In the above recording method, In the colored ink composition applying step, the white ink may be applied after the non-white ink is applied.

[0296] The present invention is not limited to the above-described embodiments, and various modifications are possible. For example, the present invention includes configurations that are substantially the same as those described in the embodiments, such as configurations with the same functions, methods, and results, or configurations with the same purpose and effect. The present invention also includes configurations in which non-essential parts of the configurations described in the embodiments are replaced. The present invention also includes configurations that achieve the same effects as the configurations described in the embodiments, or configurations that can achieve the same purpose. The present invention also includes configurations in which publicly known technology is added to the configurations described in the embodiments. include. [Explanation of symbols]

[0297] DESCRIPTION OF THE REFERENCE NUMERALS 1...inkjet recording device, 2...inkjet head, 2a...nozzle surface, 3...IR heater, 4...platen heater, 5...heating heater, 6...cooling fan, 7...pre-heater, 8...ventilation fan, 9...carriage, 10...recording medium, 11...platen, 12...cartridge, 13...carriage moving mechanism, 14...motor as transport means, 15a, 15b, 15c, 15d...colored ink nozzle group, 16...resin liquid nozzle group, CONT...control unit.

Claims

1. A recording method performed using an ink set including a colored ink composition that is an aqueous inkjet ink containing a pigment and an aqueous resin liquid composition containing a resin, the method comprising: a colored ink composition adhesion step of adhering the colored ink composition to a recording medium by an inkjet method; a resin liquid composition adhesion step of adhering the resin liquid composition to the recording medium, wherein in the recording medium, the colored ink composition and the resin liquid composition are adhered in an overlapping manner, the recording medium is a low-absorption recording medium or a non-absorption recording medium, the recorded matter recorded by the recording method is used after being subjected to a sealant film treatment on the recording surface, the resin liquid composition contains a urethane resin having an alicyclic structure or an aromatic ring structure and an acid value of 50 to 100 mgKOH / g, the recording method, wherein the urethane resin is resin particles.

2. The recording method according to claim 1, wherein the urethane resin is one using at least one selected from dicyclohexylmethane diisocyanate, isophorone diisocyanate, 1,3-bis(isocyanatomethyl)cyclohexane, m-bis(isocyanatopropyl)benzene, and m-bis(isocyanatomethyl)benzene as constituent components.

3. The recording method according to claim 1 or claim 2, wherein the ink set includes, as the colored ink composition, a white ink containing a white pigment and a non-white ink containing a non-white pigment.

4. The recording method according to claim 1 or claim 2, wherein the colored ink composition is a white ink containing a white pigment.

5. The recording method according to claim 3 or claim 4, wherein the content of the white pigment in the white ink is 5 to 20% by mass.

6. The recording method according to any one of claims 1 to 5, wherein the urethane resin is one using polytetramethylene glycol as a constituent component.

7. The recording method according to claim 6, wherein the number average molecular weight of the polytetramethylene glycol is 500 to 3000.

8. The recording method according to any one of claims 1 to 7, wherein the colored ink composition contains a resin other than the urethane resin.

9. The recording method according to claim 8, wherein the colored ink composition contains an acrylic resin.

10. The recording method according to claim 8, wherein the content of the resin other than the urethane resin is 10% by mass or less based on the total mass of the colored ink composition.

11. The recording method according to any one of claims 1 to 10, wherein the content of the urethane resin in the resin liquid composition is 1 to 15% by mass.

12. The recording method according to any one of claims 1 to 11, wherein the resin liquid composition does not contain a nitrogen-containing solvent in an amount exceeding 10% by mass.

13. The recording method according to any one of claims 1 to 12, wherein the step of applying the resin liquid composition is performed prior to the step of applying the colored ink composition.

14. The recording method according to any one of claims 1 to 3, wherein in the step of applying the colored ink composition, a non-white ink containing a non-white pigment and a white ink containing a white pigment are used as the colored ink composition, and the non-white ink and the white ink are applied in an overlapping manner.

15. The recording method according to claim 14, wherein in the step of applying the colored ink composition, the white ink is applied after the non-white ink has been applied.

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