JP2015124278A - Inkjet ink composition for water pressure transfer and printed matter using the composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink composition that can give a high-precision pattern even on an ink-receiving layer for a water pressure transfer process without degrading discharge performance and easy maintenance property of an inkjet ink, and that can impart high-quality decoration to a three-dimensional shape.SOLUTION: The inkjet ink composition for water pressure transfer is an ink composition to be used for forming a pattern by inkjet printing on a water pressure transfer film which comprises a water-soluble or water-swellable film and an ink-receiving layer that is laminated on one surface of the water-soluble or water-swellable film and has enough flexibility to follow deformation of the film. The ink composition comprises at least a pigment, a binder resin, and an organic solvent; and the organic solvent comprises at least a first organic solvent having a boiling point of 120°C or higher and lower than 200°C, and a second organic solvent having a boiling point of 200°C or higher.

Description

  The present invention relates to a non-aqueous ink jet ink composition for forming a pattern on a hydraulic transfer film by ink jet printing and a printed film printed using the ink composition.

  With hydraulic transfer, a water-soluble or water-swellable film printed with decorative patterns such as wood grain or marble pattern is floated on the surface of the water, and the transferred image is pressed by pressing the transferred object with the film softened. Since this is a transfer method and can be transferred even to a three-dimensional shape having a curved surface, it is used for providing a pattern to a three-dimensional object that cannot be handled by a flat printing apparatus.

  Currently used decorative patterns on transfer films are mainly formed by the gravure printing method. While the gravure printing method is suitable for large-scale printing of the same pattern, small-volume printing is not suitable because the ratio of the plate making cost to the printing cost becomes high. For this reason, in the case of low-volume, multi-product printing that is difficult to handle by gravure printing, an ink-jet printing method that does not require plate making costs is suitable. As shown in Patent Document 1, ink-jet printing is suitable for on-demand production because the decoration pattern can be easily changed, and can respond quickly to individual design requirements.

  In gravure printing, the viscosity of the ink itself to be printed is high and solidifies without flowing even after printing, so that a pattern can be formed directly on a water-soluble or water-swellable film. On the other hand, in ink-jet printing, the ink viscosity used is low and the solid content concentration is low, so the droplets wet and spread before drying and solidification, and draw the pattern directly on the water-soluble or water-swellable film. It is difficult. Therefore, in order to solidify while maintaining a state close to the droplet landing diameter immediately after landing, it is necessary to provide an ink receiving layer on the surface of the transfer film to be printed.

  The original purpose of the ink receiving layer is as described above, but from the current application of hydraulic transfer, it must not only absorb ink but also have sufficiently extensible material properties. This is a cause of deterioration in the quality of the pattern if the transfer object is pressed against the transfer film and is not closely adhered along the shape of the transfer object. In order to impart extensibility to materials, it is necessary to design materials such as softening the molecular structure, reducing the molecular weight, and suppressing intermolecular interactions. In other words, increasing the flexibility tends to weaken the film strength, so that the resistance to the solvent is weakened, and there is a concern that the ink having strong solubility may be eroded. Thus, it is necessary to recognize that the ink receiving layer for hydraulic transfer is different from the ink receiving layer of general inkjet paper, and the transfer film can be adjusted by adjusting the ink composition to match the ink receiving layer. High quality picture can be realized on top.

Japanese Patent No. 3952748

  Ink jet inks suitable for water pressure transfer are required to have not only stable ink jet ejection performance but also print quality capable of realizing high-definition printing on a transfer film having an ink receiving layer. Many inks with good ejection properties that are less likely to cause nozzle clogging have been proposed and are also sold for commercial inkjet printers.

  However, when printing is performed on a transfer film with a conventional ink jet ink having good ejection properties, sufficient print quality cannot be obtained because the color is blurred or the color is faint. This is because the resin structure is optimized by the material design that emphasizes the extensibility of the ink receiving layer suitable for the hydraulic transfer process, and as a result, the ink receiving layer of general inkjet paper has a low ink permeability and solvent power. This is because the influence is different.

  Ink-jet ink is dropped onto the ink receiving layer, and the colored pigment is fixed by absorbing the solvent component. However, in order to withstand the subsequent hydraulic transfer process, the ink between the fixing pigment and the surface of the ink receiving layer is fixed. Adhesion is also an important factor, and dedicated ink composition design is indispensable. In that case, it is necessary to perform printing with a general-purpose printer and to have sufficient maintenance.

  Inkjet printing on a hydraulic transfer film in this way requires an ink design that is different from conventional inkjet printing, and it is based on an existing water-soluble film and has an ink receiving layer. It was difficult to obtain an ink-jet ink capable of performing good ink-jet printing on a film.

  The present invention has been made in view of the above-mentioned conventional problems, and the object thereof is not to impair the ejection performance and ease of maintenance of ink-jet ink, and the high-definition pattern also in the ink receiving layer for hydraulic transfer. And providing an ink composition capable of giving a high-quality decoration to a three-dimensional shape.

  In order to solve the above problems, an ink composition according to the present invention comprises a water-soluble or water-swellable film and a flexible ink-receiving layer that can follow deformation of the film on one side of the film. An ink composition for forming a pattern by ink jet printing with respect to the hydraulic transfer film formed, wherein the ink composition contains at least a pigment, a binder resin, and an organic solvent, The organic solvent includes at least a first organic solvent having a boiling point of 120 ° C. or higher and lower than 200 ° C. and a second organic solvent having a boiling point of 200 ° C. or higher.

  The ink composition has a viscosity at 20 ° C. of 2 mPa · s or more and 4 mPa · s or less, and contains 8 wt% or more and 11 wt% or less of a solid content containing the pigment and the binder resin. One organic solvent may include a glycol ether-based and / or glycol ester-based organic solvent, and the second organic solvent may include a glycol ether-based organic solvent.

  The ink receiving layer may be made of an acrylic resin, and the binder resin may be made of methyl methacrylate.

  The organic solvent may include at least one of propylene glycol monomethyl ether acetate and ethylene glycol monomethyl ether acetate and / or diethylene glycol-n-butyl ether.

  In addition, the printed matter according to the present invention is a flexible ink-jet ink composition according to any one of the above that can follow the deformation of the film on a water-soluble or water-swellable film and one side of the film. A decorative pattern is formed by inkjet printing on a hydraulic transfer film obtained by laminating an ink receiving layer having the above.

  By using the non-aqueous inkjet ink composition for hydraulic transfer according to the present invention, the inkjet ink ejection performance and ease of maintenance are not impaired, and a high-definition pattern can be obtained in the ink-receiving layer for hydraulic transfer. The original shape can be decorated with high quality.

It is a cross-sectional schematic diagram of the film for hydraulic transfer which formed the decorative design of this invention. It is a schematic diagram of the inkjet printing to the film for hydraulic transfer.

  The non-aqueous inkjet ink composition according to the present invention contains at least components of a pigment, a binder resin, and a solvent, and may contain a dispersant for dispersing the pigment. Hereinafter, each component will be described.

(Pigment)
The pigment used in the non-aqueous inkjet ink composition is not particularly limited, and an inorganic pigment or an organic pigment can be appropriately selected.

  Inorganic pigments include carbon black, titanium oxide, zinc oxide, iron oxide, kaolinite, barium sulfate, calcium carbonate, silica, alumina, brown, chrome vermilion, chrome lead, chrome yellow, cadmium yellow, titanium yellow, and chrome oxide. , Cobalt green, cobalt blue, ultramarine, and bitumen.

  Organic pigments include monoazo pigments, diazo pigments, diazo condensation pigments, azomethine pigments and other azo pigments, isoindolinone pigments, isoindoline pigments, quinophthalone pigments, anthraquinone pigments, quinacridone pigments, imidazolone pigments, benzimidazolone pigments, and perinone pigments. Perylene pigments, indigo pigments, thioindigo pigments, oxazine pigments, dioxazine pigments, polycyclic pigments such as phthalocyanine pigments, and the like.

  Specifically, for example, Pigment Yellow 1, 3, 12, 13, 14, 17, 34, 35, 37, 42, 53, 65, 74, 81, 83, 93, 94, 95, 110, 111, 128 129, 138, 150, 151, 153, 154, 155, 157, 175, 180, Pigment Blue 15, 15: 1, 15: 3, 15: 4, 15: 6, 17: 1, 27, 29, 60 Pigment Green 7, 36, Pigment Red 5, 17, 22, 48: 1, 48: 2, 48: 3, 48: 4, 49: 1, 53: 1, 57: 1, 101, 112, 122, 146 177, 178, 179, 185, 202, 254, 255, Pigment Violet, 19, 23, 50, Pigment Orange 13, 16, Pigment Black 7, Pigment White , And the like 18 and 21. These pigments can be used alone or in combination of two or more.

  The average primary particle diameter of the pigment after the dispersion treatment is preferably 50 to 200 nm, more preferably 60 to 150 nm in consideration of dispersibility and dischargeability. When the average primary particle diameter of the pigment is smaller than the above range, the cohesiveness increases or the color developability deteriorates. On the other hand, if it is larger than the above range, nozzle clogging is likely to occur, and the discharge performance becomes unstable.

  The blending amount in the ink composition is preferably 1 to 15% by weight, and more preferably 2 to 10% by weight. When the amount of the pigment is less than the above range, the color developability deteriorates and only a light color can be expressed. Conversely, when it exceeds the above range, the viscosity stability of the ink composition itself deteriorates and the ink quality is sufficiently maintained. It ’s gone. Furthermore, in the hydraulic transfer method of transferring the film while extending the film to the curved surface, particularly when the blending amount of the pigment component in the ink composition is less than 3%, a sufficient image density cannot be obtained. 3 to 6% is particularly desirable.

  In order to effectively disperse these pigments in an organic solvent effectively with a pigment dispersant, it is better to have reactive functional groups (hydroxyl group, carboxy group, sulfonic acid group, etc.) on the surface of the pigment. The interaction with the pigment dispersant is preferably increased. Even if there is no reactive functional group, the reactive functional group can be introduced by performing surface treatment such as oxygen plasma treatment or UV irradiation treatment.

(Pigment dispersant)
As the pigment dispersant used in the non-aqueous ink jet ink composition, an ionic surfactant, an anionic or cationic polymer compound, or the like can be used. In particular, a polymer compound in which a basic functional group is contained in a molecular chain is preferable because it has a good adsorptivity on a pigment surface in an organic solvent and provides a stable dispersion effect.

  Specifically, as commercial products, Disperbyk-161, 162, 163, 166, 182, 183, 184, 185, 2000, 2050, 2150, manufactured by BYK Chemie, Ajinomoto Fine Techno Co., Ltd., Ajisper PB-821, 822, 881, Dispalon DA-703-50 manufactured by Enomoto Kasei Co., Ltd., and the like.

  The pigment dispersant must be appropriately selected according to the type of pigment and the type of organic solvent to be used. The blending ratio of the pigment dispersant contained in the ink composition is preferably 1 to 10% by weight, more preferably 1.5 to 8% by weight in the case of an organic pigment, and preferably 0 in the case of an inorganic pigment. It is added at 5 to 8% by weight, more preferably 1 to 5% by weight. If it is smaller than the above range, the desired dispersion performance is not exhibited and the agglomeration property becomes high. Conversely, if it is larger than the above range, the viscosity becomes high and the discharge property becomes unstable or nozzle clogging occurs.

(Binder resin)
As the resin contained in the non-aqueous inkjet ink composition used in the present invention, the constraint conditions required from the viewpoint of inkjet ejection properties and the constraint conditions required from the viewpoint of drawability on a hydraulic transfer film are compatible. Is essential.

  With respect to the ejection performance, first, it must be in a viscosity range suitable for ejection corresponding to the ink jet apparatus, with little variation in ejection state and high stability over time. For this purpose, it is desirable that the resin has a molecular weight that is not too high and that has little variation in molecular structure and degree of polymerization. In order to improve the followability of the landing shape with respect to the extension behavior of the flexible ink receiving layer, it is important that the resin has a high molecular weight and a high degree of freedom in molecular design. As the flexible ink receiving layer, acrylic resin is excellent in structural design. In this case, in consideration of the necessity of molecular design of the ink composition, an acrylic resin is suitable as the binder resin used in the present invention. Among them, methyl methacrylate is most preferable because of its high uniform solubility in the ink solvent. Is suitable.

  Other acrylic resins can be obtained by copolymerizing a single monomer or a plurality of monomers by known radical polymerization. Examples of the monomer include acrylic acid esters such as methyl acrylate, ethyl acrylate, isopropyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, ethyl methacrylate, isopropyl methacrylate, butyl methacrylate, isobutyl methacrylate, methacrylic acid. And methacrylic acid esters such as cyclohexyl acid, 2-ethylhexyl methacrylate, lauryl methacrylate, and stearyl methacrylate. In addition, monomers having a functional group can also be used, for example, carboxyl group-containing monomers such as acrylic acid, methacrylic acid, maleic acid, and fumaric acid, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, and the like. Hydroxyl group-containing acrylic acid ester, hydroxyl group-containing methacrylate ester such as 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, amide group-containing monomers such as acrylamide, methacrylamide, maleic acid amide, and fumaric acid amide, methacrylic acid And tertiary amino group-containing monomers such as dimethylaminoethyl and diethylaminoethyl methacrylate. These monomers may be used alone or in combination of two or more.

  The weight average molecular weight of the acrylic resin used in the present invention is preferably in the range of 5000 to 20000, and more preferably 7000 to 15000. When the weight average molecular weight is smaller than the above range, the film forming property, color fixing property, and glossiness which are desired to be imparted with a resin cannot be obtained. On the other hand, if it is larger than the above range, nozzle clogging is likely to occur, and the discharge performance becomes unstable.

  The blending amount in the ink composition is preferably 1 to 15% by weight, and more preferably 2 to 8% by weight. When the amount of the resin is less than the above range, there is a problem that the shape retention after landing is weak or the fixability of the pigment is deteriorated. Conversely, when the amount is more than the above range, the viscosity of the ink composition is high. Thus, the ejection stability of the ink jet is deteriorated.

  In addition to the above resins, ester resins, urethane resins, rosin resins, alkyd resins, styrene-acrylic resins, cellulose resins, etc. can be used in combination as long as the discharge performance and drawing performance do not deteriorate. It is also possible to complement the characteristics such as the landing shape and color development.

(solvent)
The main solvent contained in the non-aqueous ink-jet ink composition of the present invention is an organic solvent that can dissolve the above-mentioned pigment, a dispersant for dispersing the pigment, and a resin, and can provide solution properties suitable for ink-jet ejection. Is used. Among these, from the viewpoint of viscosity and boiling point as an ink-jet ink solvent, it is desirable to use a glycol ether or glycol ester solvent alone or in combination. In this description, the organic solvent has a boiling point of 200 ° C. or higher as a high boiling point, 120 ° C. or higher and lower than 200 ° C. as a medium boiling point, and lower than 120 ° C. as a low boiling point.

  Among glycol ethers, those having a boiling point of 180 ° C. or higher are low in volatility at room temperature and have a large ink drying inhibiting effect. Furthermore, in view of the drying suppression effect, the temperature is preferably 200 ° C. or higher.

  Considering that the viscosity of the solvent is increased by adding a pigment, a pigment dispersant, and a resin in addition to the solvent in preparing the ink, it is preferable to use a solvent of 1 to 10 mPa · s at 20 ° C.

  Examples of glycol ether solvents that have a boiling point of 200 ° C. or higher and a viscosity of 1 to 10 mPa · s at 20 ° C. are shown below. The numerical value in parentheses after the solvent name indicates the boiling point.

  For example, diethylene glycol monoethyl ether (202 ° C.), diethylene glycol-n-butyl ether (230 ° C.), diethylene glycol butyl methyl ether (212 ° C.), diethylene glycol dibutyl ether (256 ° C.), triethylene glycol monomethyl ether (249 ° C.), triethylene Glycol dimethyl ether (216 ° C.), triethylene glycol monoethyl ether (256 ° C.), dipropylene glycol-n-propyl ether (212 ° C.), dipropylene glycol-n-butyl ether (229 ° C.), tripropylene glycol monomethyl ether (242) ° C), tripropylene glycol dimethyl ether (215 ° C), and the like.

  Among them, diethylene glycol-n-butyl ether is suitable as an ink solvent because it has a high boiling point, can prevent nozzle sticking due to drying, has a low viscosity, and provides stable characteristics as an inkjet ink.

  Among glycol ether solvents, those having a low viscosity at 20 ° C. of 3 mP · s or less and a boiling point of 120 ° C. or higher and lower than 200 ° C. include, for example, ethylene glycol monomethyl ether (124 ° C.), ethylene glycol mono Examples include ethyl ether (135 ° C), propylene glycol monomethyl ether (121 ° C), propylene glycol monoethyl ether (133 ° C), propylene glycol mono-n-propyl ether (150 ° C), diethylene glycol diethyl ether (189 ° C), and the like. .

  Glycol ester solvents are preferred for stable dispersion of binder resins because of their good resin solubility, and those having a low viscosity at 20 ° C. of 3 mP · s or less and a boiling point of 120 ° C. or more include, for example, ethylene Glycol monomethyl ether acetate (146 ° C), ethylene glycol monoethyl ether acetate (156 ° C), ethylene glycol mono-n-butyl ether acetate (192 ° C), diethylene glycol monoethyl ether acetate (218 ° C), propylene glycol monomethyl ether acetate (146 ° C), dipropylene glycol monomethyl ether acetate (213 ° C) and the like.

  In view of reducing the viscosity of the whole ink, propylene glycol monomethyl ether acetate or ethylene glycol monomethyl ether acetate having a viscosity as low as about 1.2 mP · s is desirable.

(Ink manufacturing method)
The non-aqueous ink jet ink composition of the present invention can be obtained by stirring and dispersing the above-described material components using a dispersing machine such as a bead mill, a ball mill, a sand mill, an attritor, or a roll mill. The stirred and dispersed ink composition is filtered through a filter such as a membrane filter or a cartridge filter, and large particles are removed to obtain a target non-aqueous ink jet ink composition.

  In the above-described material component, the amount of the solid content including the pigment and the binder resin in the ink composition is preferably 2 to 15% by weight, and more preferably 8 to 11% by weight.

  As the organic solvent, an organic solvent having at least a boiling point of 120 ° C. or higher and lower than 200 ° C. and an organic solvent having a boiling point of 200 ° C. or higher is used. More preferably, as the organic solvent having a boiling point of 120 ° C. or more and less than 200 ° C., a glycol ether or glycol ester organic solvent having a single viscosity at 20 ° C. of 3 mPa · s or less is used alone or in combination. More preferably, a glycol ether type and glycol ester type organic solvent having a unit viscosity at 20 ° C. of 3 mPa · s or less is used in combination. The organic solvent at 200 ° C. or higher desirably contains a glycol ether organic solvent.

  Furthermore, the inkjet ink composition containing all of the above-described material components is adjusted so that the viscosity at 20 ° C. is 2 mPa · s or more and 4 mPa · s or less.

(Inkjet printing on hydraulic transfer film)
Ink jet printing on a hydraulic transfer film using the non-aqueous ink jet ink composition according to the present invention is formed by ejecting fine droplets of the ink composition by an ink jet apparatus and landing on the ink receiving layer. The As the ink jet device, various ink jet driving methods such as an electrostatic suction type, a piezoelectric method, and a bubble jet (registered trademark) method can be adopted.

  FIG. 1 is a schematic cross-sectional view of a hydraulic transfer film on which a decorative pattern is formed by inkjet printing. As the hydraulic transfer film 1 for printing, an ink receiving layer 3 is coated on a water-soluble or water-swellable film 2. As the water-soluble or water-swellable film 2, for example, a film in which a resin such as polyvinyl alcohol, polyvinyl pyrrolidone, dextrin, hydroxyethyl cellulose, acetylbutyl cellulose or the like is formed is used, and among them, polyvinyl alcohol is preferable. The ink receiving layer 3 is flexible so as to be able to follow the deformation of the film 2, and an acrylic resin or the like is used in consideration of ink absorbability. The pattern layer 4 is formed by the ink composition ejected from the ink jet apparatus landing on the ink receiving layer 3, the solvent component of the ink composition being absorbed by the ink receiving layer 3, and the solid content remaining on the ink receiving layer 3. It is formed.

  EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention further more concretely, this invention is not limited by these Examples.

(Ink adjustment method)
Hereinafter, an example of an ink adjustment method will be described. The ink is prepared by mixing a pigment dispersion obtained by mixing a pigment and a pigment dispersant, a binder resin liquid, and various solvents.

  When preparing an ink in which propylene glycol monomethyl ether acetate is the main solvent, first, Pigment Blue 15: 4 is 10% by weight as a pigment, Disperbyk-2001 manufactured by BYK Chemie is used as a pigment dispersant, 8% by weight, and propylene glycol monomethyl ether A pigment dispersion product is obtained by charging into a bead mill at a ratio of 82% by weight of acetate and dispersing for 10 hours.

  Next, a binder resin solution of an acrylic copolymer having a weight average molecular weight of 9800 obtained by radical polymerization using a monomer of propylene glycol monomethyl ether acetate and monomers of butyl acrylate and diethylaminoethyl methacrylate was added to a solid content concentration of 50%. I got it.

  When preparing an ink using ethylene glycol monoethyl ether as a main solvent, first, Pigment Blue 15: 4 is 10% by weight as a pigment, Disperbyk-2001 manufactured by BYK Chemie is used as a pigment dispersant, 8% by weight, and ethylene glycol monoethyl. It is charged in a bead mill at a ratio of 82% by weight of ether and dispersed for 10 hours to obtain a pigment dispersion.

  Next, a resin solution of an acrylic copolymer having a weight average molecular weight of 9800 obtained by radical polymerization using a monomer of butyl acrylate and diethylaminoethyl methacrylate in a solvent of ethylene glycol monoethyl ether at a solid content concentration of 50%. Obtained.

(Examples 1-6)
Examples 1 to 6 were prepared by mixing the pigment dispersion, the binder resin liquid, and various solvents at appropriate ratios to prepare a final composition having a weight% as shown in Table 1.

(Comparative Examples A to G)
In the same manner as in Examples 1 to 6, the pigment dispersion, the binder resin liquid, and various solvents were mixed in an appropriate ratio to prepare a final composition having a weight% as shown in Table 1, and Comparative Examples A to G were produced. did.

  In Examples 1 to 4 and 6, the solid content (the sum of the pigment, the pigment dispersant, and the binder resin) is 11%, whereas in Example 5, the solid content is 8%, and in Comparative Example A, the solid content is 7%. Example B has a solid content of 6%. Further, Comparative Example C is an ink which does not contain a glycol ester solvent and consists only of an ether solvent. Comparative Example D is an ink that does not contain diethylene glycol-n-butyl ether (230 ° C.), which is a high-boiling glycol ether solvent. Comparative Example E is an ink containing low-boiling ethylene glycol dimethyl ether as a main solvent and not containing high-boiling diethylene glycol-n-butyl ether. Comparative Example F is an ink containing high-boiling diethylene glycol-n-butyl ether using low-boiling ethylene glycol dimethyl ether as a main solvent. Comparative Example G is an ink containing 5% of high boiling point diethylene glycol-n-butyl ether.

<Ink evaluation 1>
The following evaluations related to the stability of inkjet printing were performed on the non-aqueous inkjet ink compositions shown in the above Examples and Comparative Examples.

(1) Adhesion prevention property Since the present ink has a high solid content ratio including the binder resin, there is a concern that the waste ink may adhere to an ink jet printer maintenance unit (nozzle wiper, suction cap) or the like. Therefore, 0.5 cc of ink was dropped onto silicon rubber and the state after being left at 35 ° C. for 48 hours was evaluated. The evaluation criteria are as follows. As the evaluation result shows that the solidification is less, there is less possibility of the waste ink sticking to the surface of the nozzle wiper or the suction cap, which is desirable for stable operation of the ink jet printer.

Evaluation criteria ○: Not solidified △: Semi-solidified but can be wiped off with main solvent ×: Solidified and cannot be easily wiped off

(2) Stable ejection performance The ink jet printer is left for 3 hours in a state where the nozzle surface is not capped at 25 ° C. and a humidity of 40%, and after that, a reference pattern for drawing whether all nozzles are ejected is drawn, The presence or absence of nozzle clogging and flight direction disturbance were confirmed. The evaluation criteria are as follows.

Evaluation criteria:
○: No problem with 95% or more nozzles △: No problem with 60% or more nozzles ×: Less than 60%

<Ink evaluation 2>
The following evaluations relating to the printability on the hydraulic transfer film were performed on the non-aqueous ink jet ink compositions shown in the above Examples and Comparative Examples. In addition, about the hydraulic transfer film with an ink receiving layer used for ink evaluation, it produced as follows.

  Applying a resin coating solution of a copolymer of butyl acrylate and methyl (meth) acrylate using ethyl acetate as a solvent to a commercially available polyvinyl alcohol film for hydraulic transfer with a thickness of 30 μm, followed by drying. An ink receiving layer made of an acrylic resin is formed on the surface.

More specifically, an acrylic resin dispersion having a solid content of 20% by weight made of an ethyl acetate solvent is prepared, and the acrylic resin dispersion is used on a water-soluble film cut to A3 size using a wire bar (No. 14). The film was dried in an oven at 70 ° C. for 5 minutes to obtain a hydraulic transfer film with an ink receiving layer having a thickness of 5 μm.

  In addition, by adding a small amount (~ 1%) of an isocyanate solution diluted with an ethyl acetate solvent to the coating solution, the ink absorption layer partially forms a three-dimensional network structure with isocyanate groups, improving the receiving characteristics. I am letting. Alternatively, as another manufacturing method, a water-soluble film wound in a roll is uniformly coated with a gravure coater, then introduced into a drying furnace in-line, and dried to form an ink receiving layer having a thickness of 5 μm. It can also be produced by winding it into a roll.

  Inkjet printing is carried out by ejecting the ink prepared in Examples and Comparative Examples by Muto Kogyo VJ-1324 onto the ink receiving layer side of the film.

  FIG. 2 shows an example of a configuration for printing on a hydraulic transfer film having an ink receiving layer formed in a roll shape. The hydrostatic transfer film 1 is softened by heating and is likely to be wrinkled. In particular, in the film having the ink receiving layer on one side, the thermal expansion coefficient of the water-soluble film of the base material and the material of the ink receiving layer is increased. Due to the difference, the occurrence of wrinkles becomes significant. On the other hand, in ink jet printing, the distance between the nozzle surface of the ink jet head 5 and the printed medium is as small as about 1 to 3 mm, and it is desirable that the medium be free of wrinkles and slack. Therefore, in the ink jet printing according to this embodiment, the ink pressure printing film 1 is transported in the transport direction 8 after the ink jet printing is completed without heating the film to which the ink droplets 6 are dropped, Heating is separately performed by the hot air 7 generated from the generator 9. In other words, since it becomes a form in which heat drying is performed after a certain period of time after performing inkjet printing, the printed image is maintained for a certain period of time without performing drying after performing inkjet printing, and even after drying It is necessary to design the ink so that the image quality is maintained as much as possible.

(3) Image Adhesiveness of Printed Film The film after ink-jet printing and drying has a form in which the pigment constituting the image is fixed on the ink receiving layer with a binder resin. If the degree of fixing is poor, there is a risk of problems such as peeling during the transfer operation. The adhesion of the pattern was evaluated according to the following criteria.
Evaluation criteria:
○: Does not peel even if the cellophane tape is applied and peeled three times. Δ: The cellophane tape is peeled and peeled off within three times. ×: Partially peeled.

(4) Image fineness after printing and drying A predetermined image is ink-jet printed on a hydraulic transfer film with an ink-receiving layer, and after 30 minutes, the bleeding of the heat-dried pattern is confirmed with a magnifier (5x) The evaluation was made according to the following criteria.
Evaluation criteria:
○: The dot shape is clear and the density in the dot is constant, and the image definition is high. Δ: Some blurring occurs and the image definition deteriorates. ×: The image has many blurring and is blurred.

(5) Bleeding of pattern after application of processing agent for transfer The hydraulic transfer film dried by inkjet printing is coated with an organic solvent on the surface of the ink receiving layer on which the pigment and binder are fixed. Transcription is performed. Specifically, the water-soluble film side with an ink receiving layer is floated on the water surface, and after a predetermined time has passed, xylene, butyl acetate, ethylbenzene, methoxybutyl acetate, propylene glycol monobutyl ether acetate is formed on the ink receiving layer side which is the upper surface. An organic solvent composed of ethyl ethoxypropylate, etc. is applied by a spray gun method, and the ABS resin as a transfer object is pressed from the ink receiving layer side of the hydraulic transfer film to transfer the pattern. In the solvent application step, it is necessary that the pigment and the binder resin do not flow while being fixed on the surface of the ink receiving layer. When it flows, it looks like a blurred pattern.

Therefore, a predetermined organic solvent was applied to the printed water-soluble film, and the degree of bleeding of the pattern on the surface was confirmed with a magnifying glass (5 times), and evaluation was performed according to the following criteria.
Evaluation criteria:
○: No bleeding is observed Δ: Slight bleeding is observed, but the pattern is maintained ×: Pattern is blurred

(Evaluation results)
The evaluation results for Examples 1 to 6 and Comparative Examples A to G are shown in Table 2.

In the ink compositions of Examples 1 to 6, good results were obtained for all the evaluation items (1) to (5).

  In Comparative Example A, the solid content of pigment, dispersant and binder resin is 7%, and in Comparative Example B, the solid content is 6%. As the solid content decreased, it was found that (3) the adhesion of the pattern of the printed film and (5) the bleeding of the pattern after application of the transfer treatment agent deteriorated. This is presumably because the adhesion between the pigment and the surface of the ink receiving layer is reduced due to a decrease in the binder resin that serves as an adhesive layer between the pigment and the surface of the receiving layer. In particular, it became clear that bleeding appears significantly in the application of an organic solvent during transfer.

  In Comparative Example C, the ink does not contain propylene glycol monomethyl ether acetate, which is a glycol ester solvent, and in this case, (5) a slight problem was observed in the bleeding of the pattern after application of the transfer treatment agent. The ink receiving layer of the hydraulic transfer film of this example functions as an ink receiving layer by absorbing and swelling the organic solvent component. The glycol ester solvent is considered to have an effect of facilitating the fixing of the pigment and the binder resin to the surface of the ink receiving layer because the solubility and uniform dispersibility in the resin are higher than the glycol ether solvent. On the other hand, it was found that a glycol ester solvent having a low boiling point has a strong solubility in the ink receiving layer resin and tends to cause cracks in the ink receiving layer by absorbing and swelling the organic solvent component. Therefore, the ink desirably contains a glycol ester solvent having a medium boiling point (120 ° C. or higher and lower than 200 ° C.).

  Comparative Example D is an ink that does not contain diethylene glycol-n-butyl ether, which is a high boiling glycol ether solvent. Comparative Example G is an ink having a content of diethylene glycol-n-butyl ether of 5%. In these inks, some problems were observed in (1) anti-sticking property and (2) ejection stability. On the other hand, as in Example 6, those containing 10% of diethylene glycol monoethyl ether, which is a high-boiling glycol ether solvent, gave good results. As a result, it has been found that it is useful for stable operation of an ink jet printer to contain about 10% of a high boiling glycol ether solvent having a high boiling point and a low vapor pressure in an ink containing a large amount of solids. The high-boiling glycol ether solvent to be added in an amount of 10% or more is preferably diethylene glycol-n-butyl ether from the viewpoint of viscosity and boiling point.

  Comparative Examples E and F are inks using ethylene glycol dimethyl ether (boiling point 85 ° C.), which is a low-boiling glycol ether solvent, as a main solvent, and exhibit stable operation as an inkjet printer (1) anti-sticking property, (2 ) Problems were found in stable ejection properties and (4) image fineness after printing and drying of the printed film. Since an organic solvent having a low boiling point and a fast drying property is used as the main solvent, it can be assumed that there are problems in (1) and (2).

  Further, (4) image fineness after printing and drying is a specific problem in the printing process of the hydraulic transfer film, and using an organic solvent having a low boiling point as the main solvent is also unfavorable for the following reasons. it is conceivable that.

  Since the ink receiving layer used for inkjet printing absorbs the ink solvent in the thickness direction, the thickness of the ink receiving layer that can be sufficiently absorbed is usually set from the ink droplet capacity and the ink absorbing power. Specifically, the thickness of the ink receiving layer is generally desired to be 20 to 30 μm or more. However, when viewed as a hydraulic transfer application, the ink-transfer-printed hydraulic transfer film with an ink-receiving layer has a process of transferring following a curved surface in a later process, which causes problems such as wrinkles in transfer. As a requirement not to be achieved, the thickness of the ink receiving layer is limited, and the thickness is limited to several μm to 10 μm.

  On the other hand, in order to perform ink-jet printing with a general-purpose and inexpensive ink-jet printer, the viscosity of the ink-jet ink needs to be in the range of about 2 to 4 mP · s, so the solid content concentration that causes the viscosity to increase is increased. Therefore, it is necessary to design many solvent components. As a result, in ink jet printing using an ink composed of an organic solvent and a hydraulic transfer film formed with an ink receiving layer that absorbs the ink, the ink receiving layer does not absorb all of the organic solvent of the ink immediately after printing. The ink receiving layer absorbs a part of the organic solvent of the landed ink, thereby relatively increasing the viscosity of the landed ink and keeping the ink from flowing on the surface. In addition to improving the adhesion between the ink receiving layer and the pigment, the ink containing the binder resin tends to increase in viscosity in a quadratic function as the ratio of the binder resin to the solvent component increases. By adding a binder resin to the ink receiving layer, only the solvent component is absorbed in the ink droplets landed on the ink receiving layer, the viscosity of the undried ink remaining on the surface of the ink receiving layer is increased, and the flow is further suppressed. Have.

  In addition, a hydraulic transfer film with an ink-receiving layer is heated in the immediate vicinity of ink jet printing, which causes wrinkles on the film as described above and makes ink jet printing unsuitable. Therefore, it is necessary to perform ink-jet printing at a temperature around room temperature that does not depend on the temperature and dry the ink for a while. If the ink is naturally dried on the surface of the ink-receptive layer before drying, the pattern is not applied as a uniform surface due to the coffee ring phenomenon, and the pattern is dried like a circle. It is. Therefore, the ink droplets on the ink receiving layer that are dripped onto the ink receiving layer and remain thick in an undried state are maintained in a state where drying is suppressed at room temperature, and are dried at once by subsequent heating. It is desirable. That is, in a hydraulic transfer film having an ink-receiving layer that absorbs an organic solvent, it is desirable that the ink-jet ink is not a low boiling point but a medium boiling point organic solvent as a main solvent, and further contains a binder resin and has a high boiling point. It is more desirable to include a part of the organic solvent.

  The effects of the present invention are summarized and summarized as follows.

[Embodiment 1]
The ink composition according to the first aspect of the present invention is a hydraulic transfer film comprising a water-soluble or water-swellable film and a flexible ink receiving layer that can follow the deformation of the film on one side of the film. On the other hand, an ink composition for forming a pattern by inkjet printing, wherein the ink composition contains at least a pigment, a binder resin, and an organic solvent, and the organic solvent has at least a boiling point. Includes a first organic solvent having a temperature of 120 ° C. or higher and lower than 200 ° C. and a second organic solvent having a boiling point of 200 ° C. or higher.

  By using the ink having such a configuration, the color pigment on the ink receiving layer can be firmly adhered to the surface of the receiving layer by the binder resin. In addition, by using an organic solvent having a boiling point of 120 ° C. or more and less than 200 ° C. as a main solvent, uneven drying of the ink on the printing surface immediately after ink-jet drawing is suppressed, and the binder resin and coloring pigment are strengthened by gently drying. It can be adhered. In addition, by containing an organic solvent having a boiling point of 200 ° C. or higher, it is possible to prevent the waste ink containing the binder resin from being easily fixed on the surface other than the printing surface, for example, a maintenance station cap of an ink jet printer. It is possible to suppress sticking to a part or the like.

[Embodiment 2]
In addition to the first invention, the ink composition according to the second invention has a viscosity at 20 ° C. of 2 mPa · s to 4 mPa · s, and the solid content containing the pigment and the binder resin is 8% by weight or more. The first organic solvent includes a glycol ether-based and / or glycol ester-based organic solvent, and the second organic solvent includes a glycol ether-based organic solvent.

  By using the ink having such a configuration, in addition to the action of the first invention, the colorability of the printing surface is improved by increasing the color pigment, and the pigment is applied to the surface of the receiving layer by increasing the binder resin. Even if the ink has a high solid content and improves the adhesion, a low-viscosity ink can be obtained, and printing can be performed with a general-purpose inkjet head and inkjet printer.

[Embodiment 3]
In the ink composition according to the third invention, in addition to the first or second invention, the ink receiving layer is made of an acrylic resin, and the binder resin is made of methyl methacrylate.

  In such a configuration, in addition to the action of the first or second invention, the surface of the receiving layer and the color pigment are adhered well and semi-dissolved in the subsequent hydraulic transfer process. Also, the receiving layer and the binder resin can be treated with the same treatment liquid.

[Embodiment 4]
In the ink composition according to the fourth invention, in addition to any one of the first to third inventions, the organic solvent is at least one of propylene glycol monomethyl ether acetate and ethylene glycol monomethyl ether acetate and / or diethylene glycol-n. -Contains butyl ether.

  With such a configuration, diethylene glycol-n-butyl ether serves to suppress the drying of the landing ink on the ink droplets and the receiving layer, and propylene glycol monomethyl ether acetate or ethylene glycol monomethyl ether acetate is a coloring pigment and A good inkjet ink that can improve the adhesion of the binder resin to the ink receiving layer can be obtained.

[Embodiment 5]
A printed film according to a fifth aspect of the present invention is the ink composition according to any one of the first to fourth aspects of the present invention, which can follow the deformation of the film on one side of the water-soluble or water-swellable film and the film. It is a film printed matter in which a decorative pattern is formed by ink jet printing on a hydraulic transfer film formed by laminating a flexible ink receiving layer.

  By setting it as such a structure, it becomes possible to obtain the favorable inkjet printing film for hydraulic transfer.

  As described above, the non-aqueous inkjet ink composition for hydraulic transfer according to the present invention does not impair the inkjet ink ejection performance and ease of maintenance, as described with reference to the above-described Examples and Comparative Examples. Even in the ink receiving layer, a high-definition pattern can be obtained and a high-quality decoration can be applied to the three-dimensional shape.

  INDUSTRIAL APPLICABILITY The present invention enables formation of a high-quality picture layer on a film for hydraulic transfer by ink jet printing, and can be widely used as a three-dimensional decoration technique with high on-demand characteristics.

DESCRIPTION OF SYMBOLS 1 Hydraulic transfer film 2 Film 3 Ink receiving layer 4 Picture layer 5 Inkjet head 6 Ink droplet 7 Hot air 8 Transport direction 9 Hot air generator

Claims (5)

A pattern is formed by inkjet printing on a water-soluble or water-swellable film and a hydraulic transfer film that has a flexible ink-receiving layer that can follow the deformation of the film on one side of the film. An ink composition for
The ink composition includes at least a pigment, a binder resin, and an organic solvent,
The organic solvent includes at least a first organic solvent having a boiling point of 120 ° C. or higher and lower than 200 ° C. and a second organic solvent having a boiling point of 200 ° C. or higher. The ink composition has a viscosity at 20 ° C. of 2 mPa · s to 4 mPa · s,
The solid content containing the pigment and the binder resin is 8 wt% or more and 11 wt% or less,
The first organic solvent includes a glycol ether-based and / or glycol ester-based organic solvent,
The non-aqueous ink jet ink composition according to claim 1, wherein the second organic solvent contains a glycol ether organic solvent. The ink receiving layer is made of acrylic resin,
The non-water-based inkjet ink composition according to claim 1, wherein the binder resin is made of methyl methacrylate.   The non-aqueous inkjet ink composition according to any one of claims 1 to 3, wherein the organic solvent contains at least one of propylene glycol monomethyl ether acetate and ethylene glycol monomethyl ether acetate and / or diethylene glycol-n-butyl ether. object. The ink composition for inkjet according to any one of claims 1 to 4, comprising a water-soluble or water-swellable film and a flexible ink receiving layer capable of following the deformation of the film on one side of the film. A film printed matter in which a decorative pattern is formed by inkjet printing on a hydraulic transfer film formed by laminating layers.