JP2018012219A - Primer ink for ink jet recording and ink set for inkjet recording - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a primer ink for inkjet recording and an ink set for inkjet recording, which has excellent storage stability and enhanced adhesiveness with various medium to be recorded formed of a plastic film, and can improve adhesiveness, bleeding property, unevenness resistance and water resistance of images when printed with an ink composition for inkjet recording.SOLUTION: There is provided a primer ink for inkjet recording applied on a recording medium formed of a plastic film, comprising a water-soluble polyvalent metal salt as an (A) component, a hydrazine derivative having at least 2 hydrazine residues as a (B) component, at least one of an acrylic emulsion or a vinyl acetate emulsion as a (C) component, and water as a (D) component.SELECTED DRAWING: None

Description

  The present invention relates to a primer ink for inkjet recording and an ink set for inkjet recording. More specifically, the present invention has excellent storage stability, improved adhesion to various recording media made of plastic film, and image adhesion and bleeding when printed with an ink composition for inkjet recording. The present invention also relates to an ink jet recording primer ink and an ink set for ink jet recording that can improve unevenness and water resistance.

  As an image recording method for forming an image on a recording medium such as paper based on an image data signal, an electrophotographic method, a sublimation type / melting type thermal transfer method, an ink jet method and the like are known. Among these, the ink jet method can be implemented by an inexpensive apparatus, and can directly form an image on a recording medium by ejecting ink only to a required image portion. Therefore, the ink jet method can use ink efficiently, can reduce running cost, has low noise, and is excellent as an image recording method.

  However, the ink (inkjet recording ink) used in the inkjet method is mainly water-based ink. Therefore, inkjet recording ink is suitable for printing on ink-absorbing materials such as paper, but materials that are not ink-absorbing, such as synthetic resins and metals, and materials that have low ink-absorbing properties. It is not suitable for printing on (non-ink-absorbing material). Therefore, ink jet recording primer inks that can be printed on non-ink-absorbing materials such as synthetic resins and metals have been proposed.

  Patent Document 1 discloses a primer comprising at least one polymer selected from chlorinated polyolefin, vinyl acetate / acrylic copolymer, polyester, acrylate vinyl acetate copolymer, etc., on a recording medium made of a plastic film. A recording sheet has been proposed in which a layer is provided and an ink receiving layer mainly composed of a water-soluble resin or an absorbent resin is provided on the layer. Further, in Patent Document 2, a recording paper has a propylene resin film as a support, and the surface layer has a hydrazine derivative having at least two hydrazine residues and a carbonyl group-containing acrylic copolymer as a main component. A room temperature crosslinkable acrylic aqueous emulsion comprising an aqueous dispersion was applied and dried to provide a primer coating layer of a nitrogen group-containing acrylic resin layer, and an ink receiving layer was further provided on the surface of the primer coating layer. Inkjet recording paper has been proposed. Patent Document 3 proposes a recording method for printing a water-based pigment ink composition after forming a base film by applying a cyclic amide compound, a thermoplastic resin, and a main solvent to a recording medium made of a plastic film. Has been. Further, Patent Document 4 discloses that a recording medium made of polyolefin includes a fluorine / acrylic composite resin, a silicone / acrylic composite resin, a vinyl chloride / acrylic composite resin, an ethylene-vinyl chloride copolymer resin, and a chlorinated polyolefin. A recording method for printing an aqueous pigment ink composition after applying a primer layer for inkjet recording containing at least one resin selected from the group consisting of water, an organic solvent, and forming a primer layer is proposed. ing.

JP-A-10-309863 Japanese Patent Laid-Open No. 10-119428 JP 2006-281570 A Japanese Patent Application Laid-Open No. 2015-168996

  However, in the methods described in Patent Document 1 and Patent Document 2, it is necessary to provide an intermediate layer and an ink receiving layer on a recording medium made of a plastic film. In addition, this method is insufficient in bleeding and unevenness of printed matter. Further, the methods described in Patent Document 3 and Patent Document 4 do not have adhesiveness to various plastic films, and are insufficient in drying property and bleeding property of printed matter.

  The present invention has been made in view of such conventional problems, and has excellent storage stability, improved adhesion to various recording media made of a plastic film, and printing with an ink composition for inkjet recording. An object of the present invention is to provide an ink jet recording primer ink and an ink set for ink jet recording that can improve the adhesion, bleeding, unevenness and water resistance of the image when the ink is applied.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that a water-soluble polyvalent metal salt and at least two water-soluble polyvalent metal salts are used as ink-jet recording primer ink compositions to be applied to various recording media made of plastic films. In combination with a hydrazine derivative having a hydrazine residue and at least one of an acrylic emulsion or a vinyl acetate emulsion, adhesion to various recording media made of a plastic film is improved, and for inkjet recording The present invention has been completed by finding that the image printed with the ink composition is excellent in adhesion, bleeding, unevenness and water resistance. That is, the ink jet recording primer ink and ink jet recording ink set of the present invention that solve the above-described problems mainly include the following configurations.

  (1) A primer ink for ink jet recording provided on a recording medium made of a plastic film, which has a water-soluble polyvalent metal salt as component (A) and at least two hydrazine residues as component (B). A primer ink for ink jet recording comprising a hydrazine derivative, at least one of an acrylic emulsion or vinyl acetate emulsion as component (C), and water as component (D).

  According to such a configuration, the ink-jet recording primer ink has excellent storage stability. Also, by providing a primer layer with this ink jet recording primer ink, the adhesion to various recording media made of plastic film is improved, and the adhesion and bleeding of images when printed with an ink composition for ink jet recording , Unevenness and water resistance are improved.

(2) The content of the component (A) is 0.5 to 10% by mass in terms of solid content with respect to the whole primer ink for inkjet recording, and the content of the component (B) is the inkjet The amount of the component (C) is 0.5 to 10% by mass in terms of solid content with respect to the whole recording primer ink, and the content of the component (C) is 0.00 on a solid basis with respect to the whole ink jet recording primer ink. The primer ink for inkjet recording according to (1), which is 5 to 10% by mass.

  According to such a configuration, the inkjet recording primer ink is more excellent in storage stability. In addition, by providing a recording layer made of a plastic film with a primer layer made of this ink-jet recording primer ink, adhesion to various recording media made of a plastic film is improved, and printing is performed with an ink composition for inkjet recording. In this case, the adhesion, bleeding, unevenness and water resistance of the image are further improved. Furthermore, the sharpness of the obtained printed matter is improved.

  (3) The component (C) includes at least one of acrylic emulsion, styrene-acrylic emulsion, acrylic-vinyl chloride emulsion, acrylic-vinyl acetate emulsion, or vinyl acetate emulsion, (1) or (2) The primer ink for ink jet recording described in the above.

  According to such a configuration, the adhesion of the image when printed with the ink composition for ink jet recording is further improved by providing the recording medium made of the plastic film with the primer layer using the ink jet recording primer ink. .

  (4) An ink set for ink-jet recording comprising the primer ink for ink-jet recording according to any one of (1) to (3) and an ink composition for ink-jet recording.

  According to such a configuration, a recording medium made of a plastic film is provided with a primer layer using this ink-jet recording primer ink, and then printed with the ink-jet recording ink composition, whereby the adhesion of the image obtained is obtained, Bleeding and water resistance are improved.

  (5) The ink set for ink jet recording according to (4), wherein the ink composition for ink jet recording is an aqueous pigment ink jet recording ink composition.

  According to such a configuration, the water-based pigment-type ink jet recording ink composition is safer and easier to handle than the UV curable ink jet ink composition, and compared with the solvent-based ink jet ink composition. Thus, it is odorless and VOC can be reduced.

  (6) The water-based pigment-type ink jet recording ink composition includes the pigment coated with an alkali-soluble resin, a basic compound, a resin emulsion, and a water-soluble organic solvent, according to (5). Ink set.

  According to such a configuration, the aqueous pigment-type ink jet recording ink composition has high ejection reliability.

  (7) The water-based pigment-type ink jet recording ink composition includes a pigment coated with a resin obtained by crosslinking an alkali-soluble resin with a bifunctional or higher functional crosslinking agent, a basic compound, a resin emulsion, and a water-soluble organic compound. The ink set for inkjet recording according to (5) or (6), comprising a solvent.

  According to such a configuration, the aqueous pigment-type ink jet recording ink composition has high ejection reliability, good bleeding, and a high color gamut.

  According to the present invention, the storage stability is excellent, the adhesion with various recording media made of a plastic film is improved, and an image of an image when printed with an ink composition for inkjet recording on a recording medium made of a plastic film. It is possible to provide an ink jet recording primer ink and an ink jet recording ink set that can improve adhesion, bleeding, and water resistance.

[Primer ink for inkjet recording]
The ink jet recording primer ink (hereinafter also referred to as primer ink) according to an embodiment of the present invention is provided on a recording medium made of a plastic film. The primer ink comprises a water-soluble polyvalent metal salt as component (A), a hydrazine derivative having at least two hydrazine residues as component (B), and an acrylic emulsion or vinyl acetate emulsion as component (C). At least any one of these and water which is (D) component.

<(A) component>
The primer ink contains a water-soluble polyvalent metal salt as the component (A). Examples of the water-soluble polyvalent metal salt include dissociable salts of alkaline earth metals such as Ca and Mg. Specifically, the water-soluble polyvalent metal salt includes calcium nitrate, CaCl ₂ , Ca (OH) ₂ , (CH ₃ COO) ₂ Ca, MgCl ₂ , Mg (OH) ₂ , (CH ₃ COO) ₂ Mg, (HCOO) ₂ Ca, MgSO _{4 and the} like are exemplified. Among these, the water-soluble polyvalent metal salt is preferably a calcium salt, and may be calcium nitrate, CaCl ₂ , Ca (OH) ₂ , (CH ₃ COO) ₂ Ca, (HCOO) ₂ Ca, or the like. More preferred.

  The content of the water-soluble polyvalent metal salt is not particularly limited. As an example, the content of the water-soluble polyvalent metal salt is preferably 0.5% by mass or more, more preferably 1% by mass or more in terms of solid content in the primer ink. The content of the water-soluble polyvalent metal salt is preferably 10% by mass or less, more preferably 5% by mass or less in terms of solid content in the primer ink. When the content of the water-soluble polyvalent metal salt is less than 0.5% by mass, the resulting printed matter is liable to decrease in sharpness and bleeding. On the other hand, when the content of the water-soluble polyvalent metal salt exceeds 10% by mass, the printed matter obtained tends to have poor water resistance.

<(B) component>
The primer ink contains a hydrazine derivative having at least two hydrazine residues as component (B). Examples of the hydrazine derivative having at least two hydrazine residues include the following dicarboxylic acid dihydrazides containing 2 to 10, particularly 4 to 6 carbon atoms. Among these, hydrazine derivatives having at least two hydrazine residues are acid dihydrazide, malonic acid dihydrazide, succinic acid dihydrazide, glutaric acid dihydrazide, adipic acid dihydrazide, sebacic acid dihydrazide, maleic acid dihydrazide, fumaric acid dihydrazide and / or Itaconic acid dihydrazide, aliphatic water-soluble dihydrazine having 2 to 4 carbon atoms, such as ethylene-1,2-dihydrazine, propylene-1,3-dihydrazine and butylene-1,4-dihydrazine are preferred Of these, adipic acid dihydrazide, isophthalic acid dihydrazide, and sebacic acid dihydrazide are more preferable.

  The content of the hydrazine derivative having at least two hydrazine residues is not particularly limited. For example, the content of the hydrazine derivative having at least two hydrazine residues is preferably 0.5% by mass or more and preferably 1% by mass or more in terms of solid content in the primer ink. More preferred. In addition, the content of the hydrazine derivative having at least two hydrazine residues is preferably 10% by mass or less, more preferably 5% by mass or less in terms of solid content in the primer ink. When the content is less than 0.5% by mass, the primer ink tends to have poor adhesion to the polyolefin film. On the other hand, if it exceeds 10% by mass, the hydrazine derivative is not completely dissolved, and the storage stability of the primer ink tends to be lowered.

<(C) component>
The primer ink contains at least one of an acrylic emulsion and a vinyl acetate emulsion as the component (C). In the present embodiment, those acrylic emulsions or vinyl acetate emulsions having good stability even in the presence of a water-soluble polyvalent metal salt can be used.

  The content of the component (C) is not particularly limited. As an example, the component (C) is preferably 0.5% by mass or more, more preferably 1% by mass or more in terms of solid content in the primer ink. Further, the component (C) is preferably 10% by mass or less, more preferably 5% by mass or less in terms of solid content in the primer ink. When the content of the component (C) is less than 0.5% by mass, the primer ink tends to have poor adhesion to a polyester film and a nylon film. On the other hand, when the content of the component (C) exceeds 10% by mass, the storage stability of the primer ink tends to decrease.

  The acrylic emulsion preferably has good stability even in the presence of a water-soluble polyvalent metal salt. For example, the acrylic emulsion is an acrylic emulsion, a styrene-acrylic emulsion, an acrylic-vinyl acetate emulsion, an acrylic-vinyl chloride emulsion, an acrylic-silicone emulsion, an acrylic-colloidal silica emulsion, or the like. Among these, acrylic emulsions having a glass transition temperature of −10 to 50 ° C. are more preferable from the viewpoint of good adhesion to the recording medium.

  The vinyl acetate emulsion preferably has good stability even in the presence of a water-soluble polyvalent metal salt. Among these, a vinyl acetate emulsion having a glass transition temperature of −10 to 50 ° C. is more preferable from the viewpoint of good adhesion to a recording medium.

  Among these, since the component (C) has good adhesion to the recording medium, acrylic emulsions are acrylic emulsion, styrene-acrylic emulsion, acrylic-vinyl acetate emulsion, acrylic-vinyl chloride type. It is preferable to include at least one of an emulsion and a vinyl acetate emulsion.

<(D) component>
The primer ink contains water as component (D). The water content is not particularly limited. The water content may be the remainder of the primer ink other than the components (A) to (C) and the optional components described below.

<Optional component>
In addition to the components (A) to (D) described above, the primer ink may contain optional components as necessary. Examples of optional components include emulsions such as chlorinated polyolefin emulsions, water-soluble organic solvents, and various additives. Examples of the additive include a surfactant, a storage stability improver, and an antifoaming agent.

  As the chlorinated polyolefin emulsion, a polyolefin resin is chlorinated and emulsified. Examples of the chlorinated polyolefin include chlorinated polypropylene resins and chlorinated polyethylene resins. In the present embodiment, a chlorinated polyolefin emulsion having good stability even in the presence of a water-soluble polyvalent metal salt is used. The chlorine content in the chlorinated polyolefin resin is not particularly limited. For example, the chlorine content is preferably 1% by mass or more, and more preferably 10% by mass or more with respect to the entire resin. Moreover, it is preferable that chlorine content is 40 mass% or less, and it is more preferable that it is 30 mass% or less.

  Examples of the water-soluble organic solvent include monoalcohols, polyhydric alcohols, polyhydric alcohol lower alkyl ethers, ketones, ethers, esters, nitrogen-containing compounds, and the like. These may be used in combination. In addition, it is preferable that the water-soluble organic solvent is not used from the viewpoint of the drying property of the primer layer obtained.

  Examples of the surfactant include acetylene diol and derivatives thereof, silicone surfactants, fluorine surfactants and the like.

Examples of the preservability improver include hindered amines, ultraviolet absorbers and antioxidants. Examples of hindered amines include N—CH ₃ type, N—H type, and N—OR type. Examples of UV absorbers include benzophenone UV absorbers, benzotriazole UV absorbers, salicylate UV absorbers, hydroxyphenyltriazine UV absorbers, cyanoacrylate UV absorbers, nickel complex UV absorbers, and the like. The Examples of the antioxidant include phenol-based antioxidants, amine-based antioxidants, sulfur-based antioxidants and phosphorus-based antioxidants.

  Examples of antifoaming agents include silicone antifoaming agents and pluronic antifoaming agents.

  Returning to the description of the entire primer ink, the method for producing the primer ink of this embodiment is not particularly limited. As an example, the primer ink comprises a water-soluble polyvalent metal salt (A) as a component (D), a hydrazine derivative having at least two hydrazine residues as a component (B), C) It can be produced by adding at least one of an acrylic emulsion or vinyl acetate emulsion as a component, a water-soluble organic solvent or various additives as necessary, and stirring and mixing with a disper or the like.

  The above primer ink is excellent in storage stability. In addition, by providing a recording layer made of a plastic film with a primer layer made of this ink-jet recording primer ink, adhesion to various recording media made of a plastic film is improved, and printing is performed with an ink composition for inkjet recording. In this case, the adhesion, bleeding and water resistance of the image are improved.

[Ink set for inkjet recording]
An ink set for ink jet recording (hereinafter also referred to as an ink set) according to an embodiment of the present invention includes a primer ink for ink jet recording and an ink composition for ink jet recording (hereinafter also referred to as an ink composition). The primer ink for inkjet recording is the same as the primer ink described in detail in the above embodiment.

  The above-described primer ink is used for the ink set of this embodiment. Therefore, by providing a recording medium made of a plastic film with a primer layer of primer ink and then printing with an ink composition for ink jet recording, the adhesion, bleeding and water resistance of the resulting image are improved.

<Ink composition for inkjet recording>
The ink composition for ink jet recording (hereinafter also referred to as ink composition) is not particularly limited. The ink composition of the present embodiment is preferably an aqueous pigment-type ink jet recording ink composition in that it is highly safe, odorless, and can reduce VOC. Further, the composition of the ink composition is not particularly limited. Hereinafter, as an example, the case where the ink composition is an aqueous pigment-type ink jet recording ink composition will be described.

  The ink composition preferably contains a pigment, a basic compound, a resin emulsion, and a water-soluble organic solvent. Such an ink composition has high ejection reliability.

(Pigment)
The pigment may be a pigment not coated with an alkali-soluble resin, or a pigment coated with an alkali-soluble resin. The pigment of this embodiment is preferably a pigment coated with an alkali-soluble resin in terms of excellent storage stability. Furthermore, the pigment is preferably a pigment coated with a resin obtained by crosslinking an alkali-soluble resin with a bifunctional or higher functional crosslinking agent.

  Examples of the pigment include various inorganic pigments and organic pigments that are generally used in ink jet inks. Inorganic pigments include colored pigments such as titanium oxide, bengara, antimony red, cadmium yellow, cobalt blue, ultramarine blue, bitumen, carbon black, and graphite (including achromatic pigments such as white and black), and calcium carbonate. And extender pigments such as kaolin, clay, barium sulfate, aluminum hydroxide, and talc. Examples of organic pigments include soluble azo pigments, insoluble azo pigments, azo lake pigments, condensed azo pigments, copper phthalocyanine pigments, and condensed polycyclic pigments. These may be used in combination.

  Further, as the pigment, C.I. can be expressed in that a clear hue can be expressed. I. Red pigments such as CI Pigment Red 5, 7, 12, 57: 1, 122, 146, 202, 282; I. Blue pigments such as CI Pigment Blue 1, 2, 15: 3, 15: 4, 16, 17, 60; I. Purple pigments such as Pigment Violet 19; I. Pigment Yellow 12, 13, 14, 17, 74, 83, 93, 128, 139, 151, 154, 155, 180, 185, 213 and the like yellow pigments; C.I. I. Black 7 (carbon black) and the like are preferable.

  The method for producing the pigment coated with the alkali-soluble resin is not particularly limited. For example, a pigment coated with an alkali-soluble resin may be obtained by subjecting a dispersion obtained by dispersing a pigment in an aqueous solution in which the alkali-soluble resin described below is dissolved in the presence of a basic compound to an acid precipitation method. Or by precipitating an alkali-soluble resin on the pigment surface by the ion exchange means or phase inversion emulsification method described in WO2005 / 116147, and filtering, washing with water, and drying if necessary. Can be obtained.

  The pigment coated with the alkali-soluble resin is neutralized by including in the ink a basic compound necessary for neutralizing a part of the acid group of the anionic group of the pigment coated with the alkali-soluble resin. It can be re-dispersed in an aqueous medium using various dispersers. The ratio of acid groups to be neutralized is preferably 50% or more, and more preferably 60% or more. Further, the ratio of acid groups is preferably 90% or less, and preferably 80% or less. Thereby, the dispersion stability of the obtained pigment can be improved.

  As the alkali-soluble resin, a copolymer resin that is used for dispersing pigments in ordinary inks and paints and is soluble in an aqueous medium in the presence of a basic compound can be used. For example, the alkali-soluble resin is a monomer having a carboxyl group, a monomer containing a hydrophobic group for improving the adsorptivity with a pigment, preferably an alkyl group having 12 to 24 carbon atoms. And a copolymer with a monomer having an aromatic cyclic hydrocarbon group, or a copolymer obtained by reacting these monomers with other polymerizable monomers as necessary. The

  As a monomer having a carboxyl group, acrylic acid, methacrylic acid, crotonic acid, itaconic acid, maleic acid, fumaric acid, 2-carboxyethyl (meth) acrylate, 2-carboxypropyl (meth) acrylate, maleic anhydride, Examples include maleic acid monoalkyl esters, citraconic acid, citraconic anhydride, citraconic acid monoalkyl esters, and the like.

  As a monomer containing a hydrophobic group for improving the adsorptivity with the pigment, a monomer having a long chain alkyl group, carbon of a radically polymerizable unsaturated carboxylic acid such as (meth) acrylic acid, etc. Alkyl esters having a number of 8 or more (for example, 2-ethylhexyl (meth) acrylate, octyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, 2-hydroxystearyl (meth) acrylate, etc.)), carbon number 8 or more alkyl vinyl ethers (for example, dodecyl vinyl ether), vinyl esters of fatty acids having 8 or more carbon atoms (for example, vinyl 2-ethylhexanoate, vinyl laurate, vinyl stearate, etc.), alicyclic Cyclohexyl (meth) acrylate as a monomer having a hydrocarbon group As a monomer having an aromatic hydrocarbon group, a styrene monomer such as benzyl (meth) acrylate, styrene, α-styrene, vinyltoluene, or the like, preferably an alkyl group having 12 to 24 carbon atoms. And a copolymer with a monomer having an aromatic cyclic hydrocarbon group.

  Other polymerizable monomers used as needed include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, (meth) Examples thereof include (meth) acrylic acid such as butyl acrylate and hexyl (meth) acrylate, hydroxyethyl (meth) acrylate, acrylamide and N-methylolacrylamide.

  The acid value of the alkali-soluble resin is preferably 40 mgKOH / g or more, and more preferably 70 mgKOH / g or more. Further, the acid value of the alkali-soluble resin is preferably 300 mgKOH / g or less, and more preferably 250 mgKOH / g or less. When the acid value of the alkali-soluble resin is less than 40 mgKOH / g, the dispersion stability of the aqueous dispersion of the pigment coated with the obtained alkali-soluble resin tends to be lowered. On the other hand, when the acid value of the alkali-soluble resin exceeds 300 mgKOH / g, the hydrophilicity becomes too high, so that the storage stability and water resistance are likely to be lowered.

  The molecular weight (weight average molecular weight) of the alkali-soluble resin is preferably 3000 or more, and more preferably 7000 or more. Moreover, it is preferable that the weight average molecular weight of alkali-soluble resin is 200000 or less, and it is more preferable that it is 100000 or less. When the weight average molecular weight of the alkali-soluble resin is less than 3000, the dispersion stability of the pigment and the scratch resistance of the obtained printed matter are likely to be lowered. On the other hand, when the weight average molecular weight of alkali-soluble resin exceeds 200000, a viscosity becomes high and handling property tends to fall.

  In this embodiment, the acid value is calculated based on the number of mg of potassium hydroxide theoretically required to neutralize 1 g of the alkali-soluble resin, based on the composition of the monomer used to synthesize the alkali-soluble resin. This is the theoretical acid value that was determined in an experimental manner.

  The weight average molecular weight can be measured by a gel permeation chromatography (GPC) method. For example, the weight average molecular weight is chromatographed using Water 2690 (manufactured by Waters) as a GPC apparatus and PLgel 5μ MIXED-D (manufactured by Polymer Laboratories) as a column, and the weight average in terms of polystyrene. It can be determined as molecular weight.

(Basic compound)
Basic compounds include inorganic basic compounds such as sodium hydroxide and potassium hydroxide, ammonia, methylamine, ethylamine, monoethanolamine, N, N-dimethylethanolamine, N, N-diethylethanolamine, N , N-dibutylethanolamine, diethanolamine, N-methyldiethanolamine, triethanolamine, morpholine, N-methylmorpholine, organic basic compounds such as N-ethylmorpholine, and the like. Among these, basic compounds are monoethanolamine, N, N-dimethylethanolamine, N, N-diethylethanolamine, N, N-dibutylethanolamine, diethanolamine, N-methyl because of excellent pigment dispersibility. Alkanolamines such as diethanolamine and triethanolamine are preferred. Basic compounds may be used in combination.

(Pigment coated with a resin obtained by crosslinking an alkali-soluble resin with a bifunctional or higher functional crosslinking agent)
The method for producing a pigment coated with a resin obtained by crosslinking an alkali-soluble resin with a bifunctional or higher functional crosslinking agent is not particularly limited. For example, such a pigment is prepared by first dissolving or dispersing an alkali-soluble resin in which an acid group is neutralized with a basic compound and a pigment in an aqueous solvent, and then salting out the alkali-soluble resin. Etc. to make the resin insolubilized and adhere to the pigment surface. The insolubilized resin thus adhered is neutralized with 50 to 90% of acid groups, and the resulting pigment coated with the alkali-soluble resin is dispersed to obtain a dispersion. (Specific examples of the bifunctional or higher functional epoxy compound include Epolite 40E, 100E, 200E, 400E, 70P, 200P, 400P, 1500NP, 1600, 80MF (manufactured by Kyoeisha Chemical Co., Ltd.), Denacol EX-201, EX-211. , EX-212, EX-313, EX-314, EX-321, EX-411, EX-421, EX-512, EX-521, EX-611, EX-612, EX-614, EX-614B, EX -622 (manufactured by Nagase ChemteX Corp.) etc. The amount of the bifunctional or higher functional crosslinking agent used is 50 to 90 of the acid group of the alkali-soluble resin. Is preferably neutralized with a basic compound and 10 to 100%, preferably 20 to 80%, of the remaining acid groups are crosslinked. Thus, the coated pigment can be produced by crosslinking and insolubilizing the alkali-soluble resin covering the pigment surface.

(Resin emulsion)
The resin emulsion is preferably contained in order to improve the friction resistance of the obtained printed matter. As the resin emulsion, a resin having a glass transition temperature of 20 ° C. or lower is preferable. Among them, resin emulsions are acrylic resin emulsions having a glass transition temperature of 20 ° C. or less, styrene-acrylic resin emulsions, polyester resin emulsions, polyurethane resin emulsions, polyvinyl acetate resin emulsions, polyvinyl chloride resin emulsions. Examples thereof include polybutadiene resin emulsions and polyethylene resin emulsions. Among these, the resin emulsion is preferably a styrene-acrylic resin emulsion in that the appearance and various resistances of the obtained printed matter are excellent. By using a resin emulsion having a glass transition temperature of 20 ° C. or lower, the resin emulsion tends to have good drying properties of the resulting printed film and good adhesion to a recording medium made of a plastic film.

  The content of the resin emulsion is preferably 1% by mass or more, more preferably 2% by mass or more in terms of solid content in the ink composition. Further, the content of the resin emulsion is preferably 10% by mass or less, more preferably 5% by mass or less in terms of solid content in the ink composition. When the content of the resin emulsion is less than 1% by mass in terms of solid content, the appearance and various resistances of the obtained printed matter are likely to be reduced. On the other hand, when the content of the resin emulsion exceeds 10% by mass in terms of solid content, ink ejection tends to become unstable.

In the present embodiment, the glass transition temperature is a theoretical glass transition temperature obtained by the following wood equation.
1 / Tg = W1 / Tg1 + W2 / Tg2 + W3 / Tg3 + ... + Wx / Tgx
(Wherein Tg1 to Tgx are the glass transition temperatures of the respective homopolymers of monomers 1, 2, 3,... X constituting the alkali-soluble resin, and W1 to Wx are the monomers 1, 2, 3,. Each polymerization fraction of x, Tg represents a theoretical glass transition temperature (the glass transition temperature in the wood equation is an absolute temperature).

(Water-soluble organic solvent)
Water-soluble organic solvents can be used as an aqueous medium with water. Examples of water include ion-exchanged water or distilled water from which metal ions and the like have been removed. Further, by containing a water-soluble organic solvent, the ink composition can be improved in storage stability, ejection stability, ink flying property, and the like.

  Examples of the water-soluble organic solvent include monoalcohols, polyhydric alcohols, polyhydric alcohol lower alkyl ethers, ketones, ethers, esters, nitrogen-containing compounds, and the like. These may be used in combination.

  Monoalcohols include methanol, ethanol, n-propanol, n-butanol, n-pentanol, n-hexanol, n-heptanol, n-octanol, n-nonyl alcohol, n-decanol, or isomers thereof, Examples include cyclopentanol and cyclohexanol. Among these, the monoalcohol is preferably an alcohol having an alkyl group having 1 to 6 carbon atoms.

  The polyhydric alcohols include ethylene glycol, propylene glycol, 1,3-butylene glycol, 1,4-butylene glycol, 1,2-pentanediol, 1,5-pentanediol, neopentyl glycol, 1,2-hexane. Diol, 1,6-hexanediol, 1,2-cyclohexanediol, heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, glycerin, pentaerythritol, diethylene glycol, dipropylene glycol , Triethylene glycol, tetraethylene glycol, polyethylene glycol, polypropylene glycol, thiodiglycol and the like.

  The lower alkyl ethers of polyhydric alcohols include ethylene glycol monomethyl ether, ethylene glycol dimethyl ether, ethylene glycol monoethyl ether, ethylene glycol diethyl ether, ethylene glycol monopropyl ether, ethylene glycol isopropyl ether, ethylene glycol monobutyl ether, ethylene glycol isobutyl. Ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, dipropylene glycol mono-n-propyl ether, dipropylene glycol Roh -n- butyl ether and the like.

  Examples of ketones include acetone, methyl ethyl ketone, methyl butyl ketone, methyl isobutyl ketone, diisopropyl ketone, cyclopentanone, and cyclohexanone.

  Examples of ethers include isopropyl ether, n-butyl ether, tetrahydrofuran, tetrahydropyran, 1,4-dioxane and the like.

  Esters include propylene carbonate, methyl acetate, ethyl acetate, propyl acetate, isopropyl acetate, butyl acetate, isobutyl acetate, amyl acetate, ethyl lactate, ethyl butyrate, dibutyl phthalate, dioctyl phthalate, and ε-caprolactone, ε-caprolactam And the like.

  Examples of nitrogen-containing compounds include urea, 2-pyrrolidone, N-methyl-2-pyrrolidone, octyl pyrrolidone and the like.

  The content of the water-soluble organic solvent is preferably 20 to 40% by mass in the ink composition. When the content of the water-soluble organic solvent is less than 20% by mass, nozzle clogging is likely to occur. On the other hand, when the content of the water-soluble organic solvent exceeds 40% by mass, the drying property on the film tends to be lowered.

(Additive)
The ink composition of the present embodiment includes a known pigment dispersant, a surfactant, an antifungal agent, a rust preventive agent, a thickener, an antioxidant, an ultraviolet absorber for adjusting the surface tension as appropriate according to the purpose. Additives such as agents, preservability improvers, antifoaming agents, and pH adjusters may be added.

  Examples of the surfactant include at least one selected from an acetylene glycol compound, a compound obtained by adding ethylene oxide to an acetylenic diol compound, a silicone surfactant, and a fluorine surfactant.

  Antifungal agents include organic sulfur, organic nitrogen sulfur, organic halogen, haloallylsulfone, iodopropargyl, N-haloalkylthio, benzothiazole, nitrile, pyridine, 8-oxyquinoline , Isothiazoline, dithiol, pyridine oxide, nitropropane, organotin, phenol, quaternary ammonium salt, triazine, thiadiazine, anilide, adamantane, dithiocarbamate, brominated indanone, benzyl Examples include bromoacetate and inorganic salt.

  Examples of the rust inhibitor include benzotriazole.

  Examples of the thickener include various synthetic polymers, polysaccharides, polysaccharide derivatives, inorganic thickeners and the like.

  Examples of the antioxidant include phenol-based antioxidants, amine-based antioxidants, sulfur-based antioxidants and phosphorus-based antioxidants.

  Examples of the ultraviolet absorber include benzophenone-based, benzotriazole-based, salicylate-based, cyanoacrylate-based, p-aminobenzoic acid esters and oxalic acid anilide-based ultraviolet absorbers.

Examples of the preservability improver include hindered amine. Examples of hindered amines include N—CH ₃ type, N—H type, and N—OR type.

  Examples of antifoaming agents include silicone compounds (silicone antifoaming agents) and pluronic compounds (pluronic antifoaming agents).

  Examples of the pH adjuster include sodium hydroxide, potassium hydroxide, potassium dihydrogen phosphate, disodium hydrogen phosphate and the like.

  Returning to the description of the entire ink composition, the method for producing the ink composition of the present embodiment is not particularly limited. For example, the ink composition comprises (1) an aqueous resin varnish in which an alkali-soluble resin is dissolved in water in the presence of a pigment and a basic compound, and a pigment dispersant as necessary. (Ball mill, attritor, roll mill, sand mill, agitator mill, etc.) After dispersing the pigment, a method of adding the remaining material, (2) Alkali-soluble resin in water in the presence of pigment and basic compound Aqueous resin varnish dissolved in, mixed with pigment dispersant as required, and then dispersed with various dispersers (ball mill, attritor, roll mill, sand mill, agitator mill, etc.) And a pigment in which an alkali-soluble resin is precipitated on the surface of the pigment by means of ion exchange or phase inversion emulsification described in WO2005 / 116147. Next, the pigment on which the alkali-soluble resin is deposited on the obtained pigment surface is neutralized with a basic compound, re-dispersed in water using various dispersers (such as a high-speed stirrer), and the remaining materials are added. , A method for preparing an aqueous pigment-type ink jet recording ink composition, (3) a pigment, an aqueous resin varnish obtained by dissolving an alkali-soluble resin in water in the presence of a basic compound, and a pigment dispersant if necessary Thereafter, the pigment is dispersed using various dispersing machines such as a ball mill, an attritor, a roll mill, a sand mill, an agitator mill, etc., and then an acid precipitation method or ion exchange means or phase inversion emulsification described in the republished WO 2005/116147. The pigment obtained by depositing an alkali-soluble resin on the surface of the pigment is obtained by the method or the like, and then the pigment obtained by depositing the alkali-soluble resin on the obtained pigment surface is made alkaline. 50-90% of the acid groups of the functional resin are neutralized with a basic compound, re-dispersed in water using various dispersing machines (high-speed stirrer, etc.), and then a bifunctional or higher functional crosslinking agent is added. Examples include a method of preparing an aqueous pigment-type inkjet ink composition by heating at 0 ° C., crosslinking, and adding the remaining materials.

  The obtained ink composition preferably has an initial viscosity adjusted to 2.0 mPa · s or more, and more preferably adjusted to 3.0 mPa · s or more. The initial viscosity of the ink composition is preferably adjusted to 10.0 mPa · s or less, and more preferably adjusted to 7.0 mPa · s or less. The static surface tension of the ink composition is preferably adjusted to 27 to 32 mN / m.

  An ink set comprising the above ink composition is provided with a primer layer made of a primer ink on a recording medium made of a plastic film, and then printed with the ink composition, whereby the adhesion, bleeding and water resistance of the resulting image are obtained. Improves.

[Printing method of ink set for inkjet recording]
A method for printing an ink set for inkjet recording according to an embodiment of the present invention (hereinafter also referred to as a printing method) is a method for printing on a recording medium using an ink set containing a primer ink and an ink composition.

  Examples of the recording medium include plastic films such as polyolefin films, polyester films, and nylon films. The primer ink is provided on the recording medium by coating or inkjet printing on the recording medium made of a plastic film.

  The coating method is not particularly limited. The coating can be performed using various conventionally known coating apparatuses. For example, the coating can be performed by using various coating apparatuses such as a blade coater, an air knife coater, a roll coater, a bar coater, a gravure coater, a rod blade coater, a lip coater, a curtain coater, and a die coater.

  The ink jet printing method is not particularly limited. For example, the primer ink can be ejected from a nozzle onto a recording medium after being accommodated in an ink cartridge and mounted in an ink jet recording apparatus such as a single pass system. In addition, the ink composition is accommodated in an ink cartridge, mounted on an ink jet recording apparatus such as a single-pass method, and then ejected from a nozzle onto a recording medium. At this time, the ejected primer ink is appropriately dried to form a primer layer. Thereafter, the ink composition is jetted onto the primer layer. As a result, an image can be formed on the recording medium.

  According to the above printing method, an image excellent in adhesion, bleeding and water resistance can be formed on a recording medium made of a plastic film.

  Hereinafter, the present invention will be described more specifically with reference to examples. The present invention is not limited to these examples. Unless otherwise specified, “%” means “mass%” and “parts” means “mass parts”.

The raw materials used and the preparation methods are shown below.
Component (A) (water-soluble polyvalent metal salt):
(A-1) Calcium acetate (A-2) Calcium formate (A-3) Calcium nitrate (A-4) Calcium chloride (A-5) Magnesium chloride (B) component (hydrazine having at least two hydrazine residues Derivatives):
(B-1) Adipic acid dihydrazide (B-2) Sebacic acid dihydrazide (C) component (acrylic emulsion or vinyl acetate emulsion):
(C-1) Acrylic emulsion (Viniblanc 2687, manufactured by Nissin Chemical Industry Co., Ltd.)
(C-2) Styrene-acrylic emulsion (NeoCryl XK-88, manufactured by DSM Neoresins)
(C-3) Acrylic-vinyl chloride emulsion (Viniblanc 711, manufactured by Nissin Chemical Industry Co., Ltd.)
(C-4) Acrylic-vinyl acetate emulsion (Vinibrand A70J9, manufactured by Nissin Chemical Industry Co., Ltd.)
(C-5) Acrylic-silicone emulsion (Charine R-170S, manufactured by Nissin Chemical Industry Co., Ltd.)
(C-6) Vinyl acetate emulsion (Viniblanc 1129, manufactured by Nissin Chemical Industry Co., Ltd.)
(Other ingredients)
Surfactant: Olfine E1010 (solid content 100%, HLB13, manufactured by Nissin Chemical Industry Co., Ltd.)

<Preparation of primer ink>
According to the mass ratio shown in Table 1 below, the components (A) to (D) and the surfactant were stirred and mixed to prepare primer inks of Examples 1 to 24 and Comparative Examples 1 to 4.

<Preparation of ink composition 1>
(Water-based resin varnish)
25 parts by mass of acrylic acid / lauryl acrylate / benzyl methacrylate / styrene copolymer having a glass transition temperature of 40 ° C., a weight average molecular weight of 30000 and an acid value of 185 mg KOH / g, 3.9 parts by mass of potassium hydroxide and 71.1 parts by mass of water And an aqueous resin varnish having a solid content of 25% was prepared.

(Preparation of aqueous black ink base)
48 parts by mass of water was added to 32 parts by mass of the aqueous resin varnish and mixed to prepare a resin varnish for pigment dispersion. To this varnish, 20 parts by mass of carbon black (trade name Printex 90, manufactured by Degusa (currently Orion Engineered Carbons, hereinafter the same)) is added, and after stirring and mixing, the mixture is mixed with a wet circulation mill. An aqueous black ink base was prepared.

  After diluting the above black ink base with water so that the pigment concentration is 5%, 5% of cation exchange resin (DOWEX MONOSPHERE (H) 650C, manufactured by Dow Chemical Co., Ltd.) is added to the diluted solution and stirred. Then, ion exchange was performed until the pH was less than 4, to obtain a resin-coated pigment. Thereafter, the ion exchange resin was filtered through a mesh and suction filtered to prepare a water-containing cake (solid content 25%) containing a resin-coated pigment.

(Production of aqueous pigment dispersion)
Sodium hydroxide required for neutralizing 80% of the alkali-soluble resin acid value in the resin-coated pigment and water required for the pigment concentration to be 12% are added to the water-containing cake, and a high-pressure emulsifying dispersion device (Gorin homogenizer) is added. (APV GAULIN INK.)) To obtain an aqueous pigment dispersion.

  Next, 34 parts by mass of the above aqueous pigment dispersion, 7 parts by mass of a resin emulsion (Neoacryl A-1092 (solid content 48.5%, styrene-acrylic emulsion, manufactured by DSM Neoresins, glass transition temperature 6 ° C.)), 25 parts by mass of propylene glycol, 0.5 parts by mass of a surfactant (Olfin E1010 (100% solids, HLB13, manufactured by Nissin Chemical Industry Co., Ltd.)) and 33.5 parts by mass of water were mixed with stirring. Ink composition 1 was prepared.

<Preparation of ink composition 2>
(Water-based resin varnish)
25 parts by mass of a copolymer of acrylic acid / lauryl acrylate (LA) / styrene = 25/30/45 having a weight average molecular weight of 30,000 and an acid value of 185 KOH mg / g was added to 4.9 parts by mass of potassium hydroxide and 70. An aqueous resin varnish having a solid content of 25% was obtained by dissolving in a mixed solution with 1 part by mass.

(Water-based pigment-based ink)
48 parts by mass of water was added to and mixed with 32 parts by mass of the aqueous resin varnish (solid content: 25%) to prepare a resin varnish for pigment dispersion. To this varnish, 20 parts by mass of carbon black (trade name Printex 90, manufactured by Degussa (currently Orion Engineered Carbons)) is added, and after stirring and mixing, the mixture is kneaded with a wet circulation mill to produce an aqueous black base. An ink was prepared.

(Manufacture of pigment coated with alkali-soluble resin)
After diluting the base ink with water so that the pigment concentration becomes 5%, 5% of cation exchange resin (DOWEX MONOSPHERE (H) 650C, manufactured by Dow Chemical Co., Ltd.) is added to the diluted solution and stirred. Ion exchange was performed until the pH was less than 4, and a resin-coated pigment was obtained. Thereafter, the ion exchange resin was filtered through a mesh and then suction filtered to obtain a water-containing cake (solid content 25%) containing a resin-coated pigment.

(Aqueous pigment dispersion) (Resin: Pigment = 8: 20)
After adding sodium hydroxide that neutralizes 65% of the alkali-soluble resin acid value in the resin-coated pigment and water with a pigment concentration of 12% to the water-containing cake containing the resin-coated pigment, high-pressure emulsification dispersion Apparatus: The mixture was stirred with a gorin homogenizer (manufactured by APV GAULIN INK.) To obtain an aqueous pigment dispersion.

(Crosslinked particle aqueous dispersion)
75 parts by weight of an aqueous pigment dispersion, 1.2 parts by weight of a bifunctional or higher functional crosslinking agent (Epolite 1600) and 23.8 parts by weight of water are added and heated at 60 ° C. for 24 hours. Obtained.

(Ink composition 2)
Next, 40 parts by mass of an aqueous pigment dispersion, 10 parts by mass of a resin emulsion (Neoacryl A1091), 21 parts by mass of propylene glycol, 1 part by mass of a surfactant (Surfinol 440, manufactured by Air Products), 28 of water The ink composition 2 was obtained by stirring and mixing parts by mass.

<Formation of primer layer>
The primer inks prepared in Examples 1 to 24 and Comparative Examples 1 to 4 were mixed with polypropylene film (P2161, 25 μm, manufactured by Toyobo Co., Ltd.), nylon film (N1100, 15 μm, manufactured by Toyobo Co., Ltd.), PET film. (E5100, 12 μm, manufactured by Toyobo Co., Ltd.) was applied with a # 4 bar coater and dried by heating to prepare a primer ink solid print (primer layer). At this time, the thickness of the primer layer was 1 μm.

(Printed matter)
On each primer layer, each ink composition was ejected and printed using an ink jet printer (PX-105) manufactured by Seiko Epson Corporation, and heated and dried. Printed materials of Comparative Examples 1 to 4 were produced.

  The storage stability of each primer ink prepared in Examples 1 to 24 and Comparative Examples 1 to 4 was evaluated according to the following evaluation method. Moreover, about each printed matter, the adhesiveness, bleeding, and water resistance were evaluated according to the following evaluation methods. The results are shown in Table 1.

<Storage stability>
Each primer ink was filled in a glass bottle and allowed to stand at 60 ° C. for 7 days. Then, separation and precipitation were observed, and storage stability was evaluated according to the following evaluation criteria.
(Evaluation criteria)
○: The primer ink was uniform without separation of liquid phase and precipitates.
Δ: In the primer ink, separation of liquid phase and slight deposits were observed.
X: In the primer ink, separation of liquid phase and precipitates were observed, and the primer ink was non-uniform.

<Adhesion>
The adhesive layer side surface of an adhesive sheet (Cellotape (registered trademark)) manufactured by Nichiban Co., Ltd. was attached to the surface of each printed material and peeled off. The adhesion was evaluated according to the following evaluation criteria.
(Evaluation criteria)
○: The printed matter did not peel at all.
Δ: A part of the printed material was peeled off.
X: The whole printed matter of the part which affixed the adhesive sheet peeled.

<Bleed>
A thin line of about 0.3 mm was printed on the surface of each printed matter, the thickness due to bleeding was observed, and bleeding was evaluated according to the following evaluation criteria.
(Evaluation criteria)
○: The printed matter was free from bleeding and could be printed with the same thickness.
(Triangle | delta): Although thickening was seen partially in the printed material, 2 times or more of thickening was not observed.
X: The printed material was observed to be twice as thick as a whole.

<Water resistance>
Letters were printed on the surface of each printed material, the state of the printed material was observed after rubbing 20 times with a wet cotton swab, and water resistance was evaluated according to the following evaluation criteria.
(Evaluation criteria)
○: Printing was not faint.
Δ: The print was slightly faint, but the characters were clearly readable.
×: Printing was faint and characters could not be read.

  As shown in Table 1, the primer compositions of the present invention containing the components (A) to (D) all have good storage stability, and the obtained printed matter has good adhesion, bleeding, and water resistance. The property was excellent. On the other hand, in the ink set containing the primer composition of Comparative Example 1 that does not contain the water-soluble polyvalent metal salt that is the component (A), a lot of bleeding occurred in the obtained printed matter. Moreover, the ink set containing the primer composition of Comparative Example 2 that does not contain the component (C) was particularly inferior in adhesion to nylon or PET film. Furthermore, the ink set containing the primer composition of Comparative Example 3 which does not contain a hydrazine derivative having at least two hydrazine residues as the component (B) was particularly inferior in adhesion to a polypropylene film. In addition, the ink set containing the primer composition of Comparative Example 4 that does not contain the component (A) and the component (C) not only bleeds when applied to various recording media, but particularly nylon. And adhesion to PET film was poor.

Claims (7)

It is a primer ink for inkjet recording provided on a recording medium made of a plastic film,
(A) a water-soluble polyvalent metal salt as a component;
(B) a hydrazine derivative having at least two hydrazine residues as a component;
(C) at least one of an acrylic emulsion or a vinyl acetate emulsion as a component;
(D) Primer ink for inkjet recording containing water which is a component. The content of the component (A) is 0.5 to 10% by mass in terms of solid content with respect to the whole primer ink for inkjet recording,
Content of the said (B) component is 0.5-10 mass% in conversion of solid content with respect to the said whole primer ink for inkjet recording,
2. The ink jet recording primer ink according to claim 1, wherein the content of the component (C) is 0.5 to 10% by mass in terms of solid content with respect to the whole ink jet recording primer ink.   The component (C) includes at least one of an acrylic emulsion, a styrene-acrylic emulsion, an acrylic-vinyl chloride emulsion, an acrylic-vinyl acetate emulsion, or a vinyl acetate emulsion. Primer ink for inkjet recording.   An ink set for inkjet recording, comprising the primer ink for inkjet recording according to any one of claims 1 to 3 and an ink composition for inkjet recording.   The ink set for ink jet recording according to claim 4, wherein the ink composition for ink jet recording is an aqueous pigment ink jet recording ink composition.   6. The ink set for ink jet recording according to claim 5, wherein the aqueous pigment type ink jet recording ink composition comprises a pigment coated with an alkali-soluble resin, a basic compound, a resin emulsion, and a water-soluble organic solvent.   The ink composition for water-based pigment type inkjet recording includes a pigment coated with a resin obtained by crosslinking an alkali-soluble resin with a bifunctional or higher functional crosslinking agent, a basic compound, a resin emulsion, and a water-soluble organic solvent. The ink set for inkjet recording according to claim 5 or 6.